api-581, liquid ring vacuum pumps and compressors for petroleum, services

8/11/2019 API-581, Liquid Ring Vacuum Pumps and Compressors for Petroleum, Services

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API

S T D * b h l

9 6 m 0732290

0550612 27L

Liquid Ring Vacuum Pum ps and

Compressors

for

Petroleum,

Chemical, and

Gas Industry

Services

API

STANDARD 681

FIRST EDITION,

FEBRUARY 1996

American

Petroleum

Institute

YRIGHT 2002; American Petroleum Institute Document provided by IHS Licensee=Sincor Venezuela/5934214100, User=,08/14/2002 13:03:08 MDT Questions or comments about this message: please call

the Document Policy Management Group at 1-800-451-1584.



~~

A P I

STD*68L

96 m 0732290

0 5 5 0 6 3 3 0 8

Liquid Ring Vacuum Pum ps and

Compressors for Petroleum,

Chemical, and Gas Industry

Services

Manufactur ing, Distr ibut ion and Market ing Department

API STANDARD 681

FIRST EDITION, FEBRUARY 1996

American

Petroleum

Institute

YRIGHT 2002; American Petroleum Institute Document provided by IHS Licensee=Sincor Venezuela/5934214100, User=,08/14/2002 13:03:08 MDT Questions or comments about this message: please callthe Document Policy Management Group at 1-800-451-1584.



SPECIAL

NOTES

l .

API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERA L

NATURE. W ITH RESPECT TO PAR TICULAR CIRCUM STANCES, LOCAL, TATE,

AND FEDERAL LAWS

A N D

REGULATIONS SHOULD BE REVIEWED.

2.

API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANU-

F AC TUR ER S , OR S UP P LIER S TO W AR N AN D P R OP ER LY TR AIN AND EQUIP

T H E I R E M P L O Y E E S , A N D O T H E R S E X P O S E D , C O N C E R N IN G H E A L T H A N D

S F E T Y

RISKS AND PRECAUTIONS,NOR UNDERTAKING THEIR OBLIGATIONS

UNDE R LOCAL , STATE, OR FEDERA L LAWS.

3. INF OR MATION C ONC ER NING S AF ETY AND HEALTH R IS KSAND PROPER

P R EC AUTIONS W ITH R ES P EC T TO P AR TIC ULAR MATER IALS AND C ONDI-

TIONS SHOULD BE OBTAINED FROM THE EMPLOYER, THEF A C T U R E R

OR S UP P LIER OF HAT MA ER IA L, OR THEMATERIAL SAFETY DATA SHEET.

4. NOTHING CONTAINED

IN NY

API PUBLICATION IS TO BE CONSTRUED AS

GRANTING ANY RIGHT, BY IMPLICATIONOR OTHERWISE, FOR THE

MANU-

FACTURE, SALE, ORUSE OF ANY METHOD , APPARATUS, OR PRODU CT COV-

ER ED B Y LETTE R S P ATENT. NEITHER S HOULD ANYTHING C ONTAINED IN

ITY FOR INFRINGEMENT

OF

LET TER S PATENT.

5. GENER ALLY,APIS TANDAR DSAR ER EVIEW EDA N DREVISED,REAF-

TIME EXTENSION OF UP TO TWO YEARS W ILL BE ADDED TO THIS REVIEW

TER ITS PUBLICATION D ATE AS AN OPERATIVE A PI STANDARD OR, WHERE

AN EXTENSION HAS BEEN GRANTED, UPON REPUBLICATION.TATUS OF THE

THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL-

FIRMED, ORWITHDRAWN AT LEA ST EVERY FIV YEARS.

SOMETIMES

A ONE-

CYCLE. THIS PUBLICATION WILLNO LONGER B E IN EF F EC T

I V

YEARS AF-

PUBLICATION CAN BE ASCERTAINED FROM TH E API A UTHORING EPART-

MEN T [TELE PHON E (202) 682-8000]. A CATALOG

OF

API PUBLICATIONS AND

MATERIALS IS PUBLISHED ANNUALLY AND UPDATED QUARTERLY BY API,

1220 L STREET,N.W., WASHINGTON, D.C. 20005.

All rights reserved.No part of this work may be reproduced, stored ina retrieval system,

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r

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wise, without prior written permission from the publisher. Contact PI Publications

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Street,

N.W.,

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D.C.

20005.

Copyright

O 1996

American Petroleum Institute

YRIGHT 2002; American Petroleum Institute Document provided by IHS Licensee=Sincor Venezuela/5934214100, User=,

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A P I

S T D * b 8 L 96

0732290 0550615

T 8 0 m

FOREWORD

This standard requires the purchaser to specify certain details and features. Although it

is recognized that the purchaser may d esire to modify, delete, or amplify sections

of

the

standard, it

s

strongly recommended that such modifications, deletions,nd amplifications

be made by supplementing this standard rather thany rewriting

or

incorporating sections

of this standard into another complete standard.

Suggested revisions are invited and should be submitted to the directorf the Manufac-

turing, Distribution and Marketing Department, A merican Petroleum Institute, 1220 L

Street, N.W., Washington , D.C. 20005.

iii


08/14/2002 13:03:08 MDT Questions or comments about this message: please call




~~ ~

API STD*b81 9 6

m

0732290 0550616 917

W

CONTENTS

Page

SECTION 1-GENERAL

1.1 Scope ................................................................................................................. 1

1.2

Alternativeesigns

...........................................................................................

1

1.3

Conflictingequirements .................................................................................. 1

1.4efinition

of

Terms ........................................................................................... 1

1.5eferences

.........................................................................................................

3

1.6 Unitonversion

.................................................................................................

5

SECTION 2-BASIC DESIGN

2.1eneral

..............................................................................................................

6

2.2asings

..............................................................................................................

7

2.3asingonnections ........................................................................................... 7

2.4 xternalorcesndMoments ........................................................................... 8

2.5otatinglements .............................................................................................

8

2.6Mechanicalhafteals

.....................................................................................

9

2.7ynamics

...........................................................................................................

9

2.8Bearings,BearingHousings, and Lubrication .................................................. 11

2.9aterials

............................................................................................................

12

2.10Nam eplate and RotationArrows

.......................................................................

14

SECTION 3-SYSTEM DESIGN

3.1 ingiquidystem

...........................................................................................

15

3.2 ontrolsndnstrumentation ............................................................................ 16

3.3Driversndransmissions ................................................................................ 19

3.4CouplingsndGuards

.......................................................................................

20

3.5eltrives

.........................................................................................................

20

3.6Mountinglates ................................................................................................. 21

3.7

Piping ................................................................................................................ 22

3.8pecial

Tools

..................................................................................................... 23

SECTION 4 INSPECTION, TESTING, AND

4.1eneral .............................................................................................................. 23

4.2nspection .......................................................................................................... 24

PREPARATION FOR SHIPMENT

4.3 Testing ............................................................................................................... 25

4.4reparationorhipment .................................................................................. 27

SECTION 5-VENDOR'S DATA

5.1eneral

..............................................................................................................

28

5.2roposals ........................................................................................................... 29

5.3 Contractata

.....................................................................................................

30

APPEN DIX A-LIQUID RING VACUUM PUM P AND CO MPRE SSOR

SYSTEM DATA SH EETS

...............................................................

31

APPEN DIX B-LIQUID RING VACUUM PUMP SCHEMATIC ........................... 57

APPEN DIX C-SHAFT DEFLE CTIONSCHEMATIC ........................................... 59

APPEN DIX D-LIQUID RING VACUUM PUM P RING LIQUID FL OW

APPENDIX E-MECHANICAL SEAL AND P IP ING AR R ANGEMENT

SCHEMATICS ................................................................................ 61

SCHEMATICS

................................................................................

65

APP EN DIX F-MATERIAL LIST ............................................................................ 69

V




~~

A P I STD*bAL 9b m 0 7 3 2 2 9 0 5 5 0 6 3 7 5 3

Page

APPEND IX G-LIQUID RING VACUUM PUMPS AND COM PRESSORS

VENDOR DRAWING AND DATA REQUIREM ENTS ................

APPEND IX H-SYSTEM CONSIDERATIONS. OPERATING VARIABLES.

AND TEST PERFORMANCE CONVERSION

............................

Figure

1-Illustration of Terms

.........................................................................................

2-Bearing-Housing Vibration Limits (Antifriction Bearings) .............................

B-1-Liquid Ring Vacuum Pum p Schem atic .........................................................

C-1-Shaft Deflectio n Schem atic ..........................................................................

D-1-Liquid Ring Vacuum Pum p Ring LiquidFlow Schematics .........................

E-1-Typical Mech anical Seal Arrang ements

.......................................................

E-2-Piping for Single-Seal Arran gemen ts nd Primary Seals of

Tandem Seal Arrangements ..........................................................................

E-3-Piping

for

Throttle Bushing, Auxiliary Seal Device,andem

Seals, or Double Seals ..................................................................................

Tables

1-Driver Trip Spee ds ............................................................................................

2-Cooling Water Design Parameters

....................................................................

3-Maximum Coup ling End Floats

.......................................................................

4-Maximum Severity of Defects in Castings .......................................................

5-Performance Tolerances ...................................................................................

F-1-Material List ..................................................................................................

71

75

2

11

58

60

62

66

67

68

3

6

20

25

27

70

vi





Liquid RingVacuum Pumps

and

Compressors for Petroleum,

Chemical, and Gas Industry Services

SECTION 1 GENER A L

1.1cope

1.1.1 This standard covers the minimum requirements for

liquid ing acuum ump nd om pressor ystems or

service in the petroleum, chemical, and gas industries. This

includesbothvacuumpump and compressordesign and

system design.

1.1.2 The design of the system is critical to the successful

operation of the liquid ring vacuum pump or comp ressor.

Close attention must be paidot only to the designf the ring

liquid system b ut also to how it is integrated into the user 's

process.

1.1.3 Althoughhis tandard oversminimum equire-

ments appropriate for petroleum refinery service, purchasers

may wish to consider pumps, compressors, and systems that

do not meet all the requirements of this standard, based on

specific nonflammable, nontoxic service conditions.

Note: A bullet

o )

at the beglnning of

a

paragraph indicates that a decision

by the purchaser

1s

required . These ecisions should be indicated on the data

sheet (see Appendix A); othenvlse, they should be stated in the quotation

request

or

In the order.

1.2AlternativeDesigns

Thevendor may offer lternativedesigns.Equivalent

metric dimensions, fasteners, nd flanges may be substituted

as mutually agreed upon by the purchaser and the vendor.

1.3

Conf l ic t ing Requirements

In case of conflict between this standard and the inquiry,

or order, the information includedn the order shall govern.

1.4 Definit ion of Terms

Terms used in this standard are defined in 1.4.1 through

1.4.26

(refer to Figure

1).

1.4.1 The alarm point is a preset value of a parameter at

which an alarm sactuated owar n of a condition hat

requires corrective action.

1.4.2 The

compressor rated point

is the point on the

100

percent speed curve at the highest capacityf any specified.

1.4.3 Hydrodynamicbearings arebearings hatuse he

principles

of

hydrodynamic lubrication. Their surfaces are

oriented

so

that elativemotion orms an oil wedge to

support the load without journal-to-bearing contact.

1

1.4.4 Inlet cubicfeetper minute (ICFM ) refers to the flow

rate determined at the conditions

of

pressure, temperature,

compressibility, and gas composition, including moisture, at

the compresso r inlet flange. Actua l cubic feet per minute

(ACF M) may be used to efer o flow atanumber of

locations and should therefore not be used interchangeably

with inlet cubic feet per minute.

1.4.5

A

liquid ring vacuumpump, or compressol; isa

rotary positive-displacement machinen which gas compres-

sion

is achieved by the action of a radially bladed impeller

mo unted in an eccentric or elliptical casing whichs partially

filled with liquid.

1.4.6 Maximum llowable ifferential ressure ishe

maximum differential pressure for which the m anufacturer

has designed the equipment for continuous operation.

1.4.7 Muximum allowable speed (revolutions p er m inute)

is the highest speedat which the manufacturer's design will

permit continuous operation.

1.4.8 Maximumallowable emperature is hemaximum

continuous emperature orwhich hemanufacturerhas

designed the equipment (or any part to which the term

is

referred) when handling the specified fluid at the specified

pressure.

1.4.9 Maximum llowable acuum ishemaximum

vacuumminimumuction ressure)orwhichhe

manufacturer has designed the equipmen t, corrected for

thevaporpressure of theseal iquidat heoperat ing

temperature.

1.4.10 Maximumllowable working pressure ishe

maximum continuous pressure for which the manufacturer

has designed the equipment (orny part to w hich the term is

referred) when handling the specified fluid at the specified

temperature.

1.4.1 Maximumontinuouspeed (revolutions per

minute) is the speed at least equal to105percent of the rated

speed.Maximumontinuouspeedoronstant-speed

drivers shall be equal to the 100-percent speed.

1.4.12 Maximumdifferentialpressure is hemaximum

discharge pressure minus the minimum suction pressure that

the pump is ab le to develop when operating at the specified

speed, specific gravity, andpumping temperature.






A P I STD+b8L 96 m 0732290

0550619

626 m

2 API STANDARD 681

x

1.1

point

I I Stabilityange

F-Turndown range-bl

I I I I

I I I I

Inlet capacity

Notes:

1. Exceptwhere pecif ic umer~calelat ionships re tated,he

relat ive values implied in this f igure are assumed valuesor ~l lus t r a t ion

only.

2 . The 100 percent speed curve is determined f rom the op erat ing point

requir ing the highest head; point A in the i l lus t rat ion.

3.

The compressor rated point (CRP) s he Intersect ion on he 100

percent speed l ine corresponding to the highest f low of any operat ing

point ; point C i n the illustration.

4. Thehead-capaci tycurveat 100 percentspeedshallextend oat

leas t 115 percent of the capaci ty of the CRP. Head-capaci ty curves at

other speeds shal l be extended to equivalent capaci ty at each speed.or

example, the head-capacity curve at 105 percent speed shall e extend-

ed to at least 1.05 t imes 1.15 t imes the capaci tyof the CRP; the head-

capaci ty curve at 90 percent speed shal l be extended o at eas t 0.9

t imes 1.15 t imes capaci ty of the CRP; and

so

on. These points def ine

the approximate capaci ty l imit curve.

5. Refer to the appl icable s tandard for the compressor dr iver such as

API Standard

612

(Steam Turbine)

or

API Standard 616 (Gas Turbine)

for t r ip speed and minimum operat ing speed l imits .

6 . Refer to 2.7 for al lowable margins of cr i t ical speeds to operat ing

speeds .

l

S ee 1.4.4.

Figure 1-Illustration

of

Terms




A P I STD*bflL 96

0732290 550620

348

LIQUID RING VACUUMUMPSNDOMPRESSORS

FOR

PETROLEUM,HEMICAL,ND GAS INDUSTRYERVICES

3

1.4.13 Ma xim um discharge ressure

ishemaximum

suction pressure

plus

the maximum differential pressure that

the pump is able to develop when operating at the specified

speed, specific gravity, and pum ping temperature.

1.4.14

Maximum

sealing pressure

is the highest pressure

expected at the seals d uring ny specified static or operating

condition and during start-up and shutdown.

1.4.15

Minimum allowable temperature

is he minimum

continuous emperature orwhich hemanufacturerhas

designed the equipmen t (or any part to which the term is

referred).

1.4.1

6 Normal operating point

is the p oint at w hich usual

operation is expected and optimum efficiency is d esired.

1.4.17 The

casing

is the composite of all stationary pres-

sure-containing parts of the unit, including all nozzles, seal

glands, and other attached parts ut excluding the stationary

and rotating members of mechanical seals (see Figure E- 1,

Appendix

E).

1.4.18

Radiallyplit

refersoasingointshatre

transverse to the shaftenterline.

1.4.19

Rateddischarge pressure

is thehighestpressure

required to meethe conditions specifiedy the purchaser for

the intended service.

1.4.20

The

rated operating point

is the point at which the

vendorcertifies hatperformance is within he olerances

stated in this standard. Performan ce includes the following

factors: capacity, power, efficiency, rotative speed, and rated

suction and discharge pressures.

1.4.21 The

shutdown point

is a preset valueof a parameter

at which automatic or manual shutdown of the system s

required.

1.4.22

StandardJEow

s the flow rate expressed in volume

flow rate. IS0 standard flow rate is cubic meters per hour or

minute (m3/hor m3/m in) at an absolute pressureof 1.0 13 bar

[

14.7 pounds per square inchpsi)] and a temperatureof 0°C

(32°F). Customary units are standard cubic feet per minute

(SCFM) or million standard cubic feet per day (MMSCFD)

at an absolute pressure of

14.7

pounds per square inch and a

temperature of 60°F.

1.4.23

Total indicated runout

(TIR), alsoknownas otal

indicator reading, is the runout

of

a diameter or face deter-

mined by m easurement with a dial indicator. The indicator

reading implies an out-of-squareness equal tohe reading or

an eccentricity equal tohalf the reading.

1.4.24

Trip speed

(revolutions per m inute) is the speed at

which the independent emergency overspeed device operates

to shut down a variable speed prime mover (seeable 1).

Table

1-Driver

Trip Speeds

Trip Speed

(%

of Maximum

Driver Type Contmuouspeed)

Steam turbme

NEMA Class Aa 115

NEMA Classes

B, C,

D a

110

Gas turbine

105

Varlable speed motor

110

Reciprocatmg engme

110

'Indmte s governor class

as

specified

In

NEMA SM

23

1.4.25

Unit responsibility

refers to the esponsibility or

coordinating the technical aspects of the equipment and all

auxiliary ystems ncluded n he scope of theorder. t

includes esponsibility or eviewing such factorsas he

power requirem ents, speed, rotation, general arrangement,

couplings, ynamics, oise,ubrication, ealing ystem,

material test reports, instrumentation, piping, and testing of

components.

1.4.26 A

wet critical speed

is a rotor resonant frequency

calculated considering the additional support and damping

produced by the action of the pumped liquid within internal

running clearances at the operating conditions and allowing

for flexibility and damp ing within the bearings.

1.5 References

1.5.1 Thistandardakeseference tomerican

standards; other international or national standards may be

used as mutuallyagreedbetweenpurchaserandvendor

provided it can e shown that these standards eet or exceed

the American standards referenced.

1.5.2 Th e editions of he following standards, codes, and

specifications that are in effect at the time of publication of

this standard shall, to the extent specified herein,orm a part

of this standard. Th e applicability of chan ges in standards,

codes, and specifications that occur after the inquiry shall be

mutually agreed upon by the purchaser and the vendor.

AFBMA'

Std

7

Shaft and Housing Fits for Metric

Radialallndollerearings

(Except Tapered Rollerearings)

Conforming to Basic Boundary Plans

Std 9

Load Ratingsand Fatigue

L e f or

Ball Bearings

Std

19

Tapered RollerBearings-Radial nch

Design

I Antl-Frichon Be anng Manu facturers Association, 1235 Jefferson Davis

Hlghway, Arlington, Vlrgmia 22202.





A P I STDrb8L 96

W

0732290

0550b2L 284 W

4 API

STANDARD

681

Std 19.1

Std 20

AG MA^

9000-C90(1990)

9002

Tapered Roller Bearings-Radial

Metric Design

Radial Bearings of Ball, Cylindrical

Roller and Spherical Roller Types,

Metric Design: Conforming to Basic

BoundaryPlans:BoundaryDimen-

sions, Tolerances and Ident cation

Code.

Flexible Couplings-PotentialUnbal-

ance Class cation

Bores and Keyways for Flexible

Couplings (Inch Series)

AISC3

Manual of Steel Construction

ANSI4

B1. l

B1.20.1

B 1.20.3

B 16.1

B 16.5

B16.11

B

16.42

B73.1

B73.2

S2.19

API

Spec

5L

RP 500A

Unijìed Inch Screw Threads (UN and

UN R Thread Form)

Pipe Threads, General Purpose (I nch )

Dryseal Pipe Threads (Inc h)

Cast Iron Pipe Flanges and Flanged

Fittings, Class 2 5, 125 , 250, and 800

Pipe Flanges and Flanged Fittings,

Steel Nickel Alloy and Other Special

Alloys

Forged S teel Fittings, Socket- Welding

and Threaded

Ductile Iron Pipe Flanges and

Flanged Fitting, Class 150 and 300

Specification for Horizontal End

Suction Centrifugal Pumps fo r Chem -

ical Processes

Specijìcation for Vertical In-line

Centrijìugal Pumps for Chemical

Services

Mechanical Vibration-Balance Qual-

ity

of Rigid Rotors-Part l , Deter-

mination of Permissible Residual

Unbalance

Spe cgc ation for ine Pipe

Classijìcation of Locations for

Electrica l nstallations n Petroleum

Refineries

’American

Gear

Manufacturers Association,

1500

King Street, Suite 201,

Alexandria, Virginia 22314-2730.

American Institute of Steel Construction, 1 East Wacker Drive, Suite

3

100,

Chicago, Illinois

60601

2001.

American National Standards Institute, 11 West 42nd

Street,

New Y ork,

New York 10036.

RP 520

Std 526

Std

550

Std 610

Std 61 1

Std 615

Std 660

Std 670

Std 677

Sizing,Selection and Installation of

Pressure Relieving Devices n Refin-

eries

Flanged Steel Safety Relief Valves

Manual on Installation of Refinery

Instruments and Control Systems

(oop)

Centrifugal Pum ps fo r General Refin-

ery Service

General-Purpose Steam Turbines for

Refinery Services

Sound Control of Mechanical Equip-

men t o r Re nery Services (oop)

Shell-and-Tube Heat Exchangers fo r

General Refinery Services

Vibration, Axial-Position, and Bear-

ing-Temperature Monitoring Systems

General Purpose Gear Units fo r

Refinery Service

Manual of Petroleum Measurement Standards,

Chapter

15, Guidelines or the Use of the

International System of Units (SI) in

the Petroleum and Allied Industries”

. .

ASME’

B 1.20.1

B 16.47

B31.3

A S T M ~

A 105

A

106

A 120

A 153

A 181

Pipe Threads, General Purpose (In ch )

Large DiameterSteel Flanges: NPS

26 through NPS 60

Chemical Plant and Petroleum Refin-

ery Piping Boiler and Pressure Vessel

Code, Section V, “Non-destructive

Examination”;Section

VIII,

“Rules

for Construction of Pressu re Vessels”;

and Section X, “Welding and

Brazing

Qualifications”

Specification for Ca rbo n Steel Forg-

ings fo r Piping C omponents

Specification for SeamlessCarbon

Steel Pipe for High-Temperature

Service

Specification for Black andHot-

Dipped Zinc-Coated (Galvanized)

Welded and Seamless Steel Pipe fo r

Ordinary Uses

Specijìcation for Zinc Coating (Hot

Dip} on Iron and Steel Hardware

Spec ìcation for Carbon Steel Forg-

ings

fo r General Purpose Piping

American Soclety

of

Mechanical Englneers,

345

East 47th Street, New

American Society

foc

Testing and Materials,

1916

Race Street, Philadel-

York, New York 10017 .

phia, Pennsylvania 1910 3





A P I

S T D I b 8 1 96 m

0732290

0 5 5 0 b 2 2 110 m

LIQUID RING VACUUM

PUMPS

AND

COMPRESSORS FOR PETROLEUM, CHEMICAL, AND GAS

INDUSTRY

SERVICES 5

A 193

A 194

A

197

A 247

A 269

A 278

A 338

A 395

A 515

A 524

A 536

E 94

E

125

E 142

E 709

AWS7

E E M U A ~

D1. l

151

HEI^

Specifications for Alloy-Steel and

Stainless Steel Bolting M aterials fo r

High - Temperature Service

Specijìcation for Carbon and Alloy-

Steel Nuts for Bolts fo r High-pressure

and High-Temperature Service.

Specijìcation for Cupola Malleable

Iron

Method for Evaluating the Micro-

structure

of

Graphite in Iron Castings

Specification fo r Seamless and Welded

Austenitic Stainless Steel Tubing fo r

General Service

Specification for Gray Iron Castings

for Pressure Containing Parts for

Temperatures up to 650°F

Specijìcation for Malleable Iron

Flanges,ipe Fittings, and Valve

Parts fo r Railroad, Marine and Other

Heavy Duty Service at Temperatures

up to

650°F

3 4 5 ° C )

Specijìcation

for

Ferrite Ductile Iron

Pressure-retaining Castings fo r Use

at E levated Temperatures

Specijìcation for Carbon Steel Pres-

sure Vessel Plates for Intermediate

and Higher-Temperature Service

Specijìcation for Seamless Carbon

Steel Pipe fo r Atmospheric and Lowe r

Temperatures

Specijìcation for Ductile Iron

Castings

Guides

or

Radiographic Testing

Reference Photographs

for

Magnetic

Particle Indications on Ferrous

Castings

Method for Controlling Quality

of

Radiographic Testing

Practice fo r Magnetic Particle Exam-

ination

Structural Welding Code-Steel

Liquid Ring Vacuum Pumps and

Compressors

Pe ~o rm an ce tandard for Liquid Ring Vacuum Pumps

American Welding Society, 550 N.W. LeJeume Road, PO . Box 351040,

Miami , Hond a 33135.

TheEng ineerin g Equipment and Materials Users Assoclation,

14-15

Belgrave Square, London, U.K. WIXBPS.

Heat Exchange Institute,

1230

Keith Building, Cleveland, Ohio 441 15.

NACE'O

MR-01-75 Sulfide Stress Cracking Resistent

Metallicaterial For Oil Field

Equipment

Corrosion Engineer's Reference Book

NEMA"

SM

23 Steam Turbines fo r Mechanical Drive

Service

NFPA

70 National Electrical Code, Articles

500

and 501

496 Purged and Pressurized Enclosures

fo r Electrical Equipment

OS HA^^

29

Code

of

Federal Regulations Part

1910

PNEUROP 661214

Acceptance Specijìcation and Pe ormance Tests fo r

Liquid Ring Vacuum Pum ps

SSPC

TEMA^^

SP 6 Commercial Blast C leaning

Standard of Tubular ExchangersManufacturers Asso-

ciation

1.5.3

The purchaser and the vendor shall mutually deter-

mine the measures that must be taken to comp ly with any

governmental codes, regulations, ordinances, or rules hat

are applicable to the equipment.

1.5.4

It is the vendor's responsibility

to

invoke all applica-

ble specifications to each subvendor.

1.6

Unit Conversion

The factors in Chapter 15of the API Manual

of

Petroleum

Measurement Standards were used to convert from customary

to SI units; the resulting exact I units were then rounded

ff.

I NACE International, P.0 Box

218340,

Houston, Texas 77218-8340.

I Nauonal Electncal Manufacturers Associatlon, 2101 L. Street, N.W.,

Washmgton, D.C. 20037.

l

National Fire Protection Association, Batterymarch Park, Quincy. Massa-

chusetts 02269.

l 3

Occupational Safety and H ealth Standards.

l

European Co mmittee of Manufacturers of Compresso rs, Vacuum Pumps

and Pneuma tic Tools, c/o Britlsh Compressed Air Society, Leicestor House

& Leicestor Street, London, U

K.

WCZH 7NN.

Steel Structures Paintmg Council, 4 400 Fifth Avenue, Pittsburgh, Penn-

sylvanla 15213-2683.

l

Tubular Exchanger Manufacturers Associatlon, 25 North Broadway,

Tarrytown, New York 10591.





API STD*bl L 96

0732290

0550623

057

6 API

STANDARD 681

SECTION 2-BASIC

DESIGN

2.1 General

2.1.1 The equipment (including auxil iaries) covered by

this tandard hallbedesignedandconstructed or a

minimum service l i fe of 20 years and at least three years

of uninterrupted operation. It is recognized that this is a

design criterion.

2.1.2 Th e vendor shall assume unit responsibilityof all the

equipment and all auxiliary systems includedn the scope

of

the order.

2.1.3 The purchaser will specify heequipment'snormal

and rated operating po ints on the data sheets. T he purch aser

will also specify any other anticipated operating conditions.

2.1.4 Control of the oundpressure evel (SPL) of all

equipment furnished shall be a joint effort of the purchaser

and the vendor. The equip men t furnis hed y the vendor shall

conform o hemaximumallowablesoundpressure level

specified by the purchaser.

2.1.5 Cooling water design co nditions will be specified by

the purchaser. Note that cooling water design parameters are

particularly critical to the perform ance

of

liquid ring ma-

chines . T he lowest available cooling water temperature will

result in the best perform ance, namely, capacity and suction

pressure. The cond itions n Table 2 are suggested guidelines.

Table

2 Cool ing

Water

Design Parameters

Parameters

SI English

Cond ltions Units Unlts

Veloclty over heat exchang e

surfaces 1.5-2.5

d s

5 8

fus

Maxlmum allowable workmg

pressure

2 5.2 bara

75 psig

Test pressure

2 1 5 x MAWP

I15 psig

Maximum pressure drop

I

bar

15

psi

Maxlmu m Inlet temperature

30°C

90°F

Maxim um outlet temperature

50°C

120°F

Maxlmum temperature

rlse

20K

30°F

Minimum temperature rise'

1OK

20°F

Foulmg

factor

on

water slde 0.35m2K/kW 0.002 hr-ftZ F/Btu

Shell corrosion allowance

3

O

mm

0.125

in

Note: The vendor shall notlfy the purchaser if the cnte na form mim um em-

perature nse and velocity over heat exc hang e surfaces result in

a

conflicting

design. The criterion for veloclty over heat exchanger surfaces is Intended

to minimize water-slde fo ulmg, the criterion for minimum temperature rise

is intended to minimize the use of coolmg water. It is accepted that the

specified mm imum temperature rise may be oo restnctive

for

vacuum

pumps handlmg c onden sable vapors The purchaser will approve the final

selectlon

iGauge pressure

'Lower temperature nse may be necessary depending upon conditions and

pending purchaser approval.

Provision shall bemade for completeenting and draining

of the system.

2.1.6 Equipment shall be designed to run to the trip speed

and relief valve settings without damage.

2.1.7 Th e arrangement of the equipment, including piping

and auxiliaries, shall be developed jointly by the purchaser

and hevendor.Thearrangementshallprovideadequate

clearance areas and safe access for operation and m ainte-

nance. Any special clearance or safe acce ss areas located o n

the skid will be specified by the p urchaser.

2.1.8 Motors, electrical components, and electrical nstal-

lationsshallbesuitable for theareaclassification class,

group, and division or zone) specified by the purchaser on

the data sheets and shall meet the requirementsf NFPA 70,

Articles

500,

501,502, and

504

as well as local codes speci-

fied and furnished by the p urchaser.

2.1.9 Housings that enclose moving lubricated parts (such

as bearings, shaft seals, highly polished parts, instrum ents,

and control elements) shall be designed to minimize contam-

ination by moisture, dust, and other foreign matter during

periods of operation and idleness.

2.1.10 All equipmentshallbedesigned opermit apid

andeconomicmaintenance.Majorparts uchascasing

components and bearing housings shall be designed (shoul-

dered or cylindrically doweled) and manufactured to ensure

accurate alignment on reassembly.

2.1.1 1 The m achineand its driver shall perform on the est

stand and on their permanent foundation within the specified

acceptance criteria. After installation, the performancef the

combinedunits hall be the joint responsibility of the

purchaser and the vendor who has nit responsibility.

2.1.12 In designing the liquid ring unit, the vendor shall

take into account that many factors (such as piping loads,

alignment at operating conditions, supporting structure, and

handling during shipment and nstallation) may adversely

affect site performance.

2.1.13

Th e purchaser will specify whether the installation

is indoors (heated or unheated) or outdoors (with or without

a roof), as well as the w eather and environmental conditions

in which the equipment m ust operate (including maximum

andminimum emperatures,unusualhumidity,anddusty

or corrosive conditions). Th e unit and its auxiliaries shall

be suitable for operation u nder these specified conditions.

For purchaser's guidance, the vendor shall list in the pro-

posal any special protection that the purchaser is required

to supply.

2.1.14 All equipm ent hallbeadditionally uitable or

running onairduringcommissioning.Thevendorshall

provide air performance curves, operating guidelines, and

any additional features required.

Note:

It

may

he

necessary

to

use

a

different

ring

liquid to run on

ir.





LIQUID

RING

VACUUM PUMPS AND COMPRESSORS FOR PETROLEUM,HEMICAL,ND GAS INDUSTRYERVICES 7

2.1.15 Spare partsor themachine nd all furnished

auxiliaries shall meet the criteriaf this standard.

2.1.16 Whe n specified, the equipment feet shall be provid-

ed with vertical jackscrew s and shall be drilled with pilot

holes that

are

accessible for use n final doweling.

2.1.17 A guide to liq uid ring vacuum pump and compres-

sor nomenclature will be foundn Appendix B.

2.2

Casings

2.2.1 The stress used in design for any given material shall

not exceed the values given for that material in SectionIII,

Division 1 , of the ASM E Code.For cast materials, the factor

specified in the code shall be applied. Pressure casings of

forged steel, rolled and welded plate, or seam less pipe with

welded cover shall comply with the applicable rulesof Sec-

tion

VIII,

Division 1, of the AS ME Code . Manufacturer’s

data report forms and stamping, as specifiedn the code, are

not required.

2.2.2 Themaximum allowableworkingpressure of the

casing shall be at least equal o he specified relief valve

setting.

2.2.3 Wh ere m ore than o ne compression stage is incorpo-

rated within a single casing, the wholef that casing shall be

designed for the maxim um allowable working pressure of

the higher pressure stage.

2.2.4 Casings and supports shall be designed to have suf-

ficientstrengthand igidity to limit any change of shaft

alignment at the coupling flange, causedy the worst combi-

nation of allowable pressure, torque, and piping forces and

moments, to 50 micrometers (0.002 nch) at staticcondi-

tions. Under dynamic conditions, the calculated shaft deflec-

tion at the coupling flange shall n ot exceed

25

microinches

(0.005

inch).Supportsandalignmentboltsshall be rigid

enoug h to perm it th e mach ine o be moved by the use of its

lateral and axial jackscrews (see AppendixC).

2.2.5 The use of tappedholes

in

vacuum and pressure

parts shall be minimized. To prevent leakage in vacuum and

pressure sections of casings, metal equal

in

thickness to at

least half the nominal bolt diameter,

n

addition to the allow-

ance for corrosion, shall be left around andelow the bottom

of drilled and tapped holes. The depth of the tapped holes

shall b e at least on e an d on e alf times the stud diameter.

2.2.6 Bolting hallbe urnished s pecified in 2.2.6.1

through 2.2.6.4.

2.2.6.1 Thedetails of threading hallconform oANSI

B1. l .

O

2.2.6.2 Studsare preferred ocapscrewsandshallhave

thefirstoneand one half threadsremovedat both ends .

When specified, studs shall be supplied.

2.2.6.3 Materialgrademarkingsshallbe ocated on the

nut end of the exposed stud.

2.2.6.4 Adequateclearance hallbeprovidedatbolting

locations to permit the use of socket or box wrenches.

2.2.6.5 Slottednut,orspanner-typeboltingshallnotbe

used unless spec ifically approv ed by the purchas er.

O 2.2.7 Jackscrews and cylindrical casing alignment dowels

or shoulders shall be provided to facilitate disassembly and

reassembly. When jackscrews are specified or required as

a

means of parting contacting faces, one of the faces shall be

relieved (counterbored or recessed) to prevent a leakingoint

or improper fit caused by marring

of

the face.

O

2.2.8 When specified, hold-down or founda tion bolt holes

shall be spot faced

o

a diameter three times thatf the hole.

2.3

CasingConnect ions

2.3.1 Casings with double flow inlet or discharge connec-

tionsshall, unless specifiedotherwise,be urnishedwith

manifolds to

a

single terminal point connection. The m ani-

folds shall be designed for the same vacuum and maximum

allowable working pressure as the casing.

2.3.2 Inlet nd utlet onnections hall be flanged r

machinedandstudded,oriented

as

specified on thedata

sheets,andsuitable or hemaximumallowableworking

pressure of the casing

as

defined in 1.4.10.

2.3.3 Casing openings for piping connections shall be at

least NPS

h

and for flammab le or oxic service shall be

flangedor machinedand tudded,or hreadedand eal

weldcd.Whenhreadedonnections are approvedor

nonflammable, nontoxic service, they shall comply with the

requirements of 2.3.3.1 through 2.3.3.5.

2.3.3.1 ThreadedconnectionsshallbeNPS

Yi

through

1% nominal pipe sizes on1.y.

O

2.3.3.2 When specified,

a

pipe nipple, preferably not more

than

150

millimeters

(6

inches) long, shall be screwed into

the threaded opening and shall comply withhe requirements

of 2.3.3.2.1 hrough2.3.3.2.3.Additional ittingsmay be

used if space

is

restricted.

2.3.3.2.1 The pipe nipple shall meet the minimum sched-

ules listed

in

Table 3.

2.3.3.2.2 The pipe nipple shall be provided with a flange

at its outer end.

2.3.3.2.3 The nipple and flange materials shall meet he

requirements of 2.3.5.

2.3.3.3

Tapped openings and bosses for pipe threads shall

conform toANSI B 16.5.




8

API STANDARD 681

2.3.3.4 Pipe threads shall be taper threads conform ing to

ANSI

B

1.20. .

2.3.4 Forlammablendoxicervicehehreaded

connection shall be seal welded; however,eal welding is not

permitted on cast ron equipment, for nstrument connec-

tions,

or

wheredisassemb ly is required ormaintenance.

Seal-weldedoints hall e

in

accordancewithASME

B

31.3.

2.3.5

Connectionswelded to thecasing shall meet he

material requirementsof the casing, including impact values,

rather than the requirem ents of the connected piping (see

2.3.3.2.3 and 2.9.3.5).

2.3.6 Openings for NPS l ,2%, 3%, 5 7, and

9

shall not

be used.

2.3.7 Tappedopeningsnotconnected to piping shall be

pluggedwith olid lugsurnished

in

accordancewith

ASME B16.1 l . As a m inimum, these plugs shal l meet the

material requirem ents of the casing. Plugs that may later

require remo val shall be of corrosion resistant material. A

lubricant that m eets heproper emperaturespecification

shall be used on all threaded co nnections. T ape shall not be

applied to threads of plugs inserted into oil passages. Plastic

plugs are not permitted.

2.3.8 Flanges shall conform to ASME B16.1, B 16.5, or

B 16.42 as applicable, except as specified n

2.3.8.1

through

2.3.8.4.

2.3.8.1 Cast iron flanges shall be flat-faced.

2.3.8.2 Flat-faced langeswith full raised-face hickness

are acceptable on casings other than cast iron.

2.3.8.3 Flanges hat are hicker or havea argeroutside

diameter han hat required by ASM E B 16.5

or

B 16.47

Series “B”

are

acceptable.

2.3.8.4 Connectionsother han hosecovered by ASME

B16.5, B16.47 Series “B” require the purchaser’s approval.

Unless otherwise specified, mating parts for these nonstand-

ard flanges shall be furnished by the vendor.

2.3.9 Machin ed and studded connections shall conform to

the facing and drilling requirementsf ASME

B

16.1,

B

16.5,

or B16.42. Stud s and nuts shall be furnished installed. The

first one and onehalf threads at b oth ends f each stud shall

be emoved.Connectionsargerhanhose overed by

ASME shall meet the requirementsf 2.3.8.4.

2.3.10 All

of

the purchaser’s connections shall be acces-

sible for disassembly without the machine being moved.

2.3.11 Casings shall be provided with a vent connection

unless theyare self-venting by the arrangem ent f the piping.

2.3.12 Casings shall be provided with sufficient drains to

ensure complete drainage.

2.3.13 Welded branches of one inch nominal size

or

less

shall be reinforced by gusset plates or otherwise adequately

supported to avoid a fatigue failure at the point of attach-

ment, particularly where a valve or other mass is supported

from the branch.

2.4 External Forces and Mom ents

The manufacturershall specify the maximum allowable ex-

ternal forces and mom entshat the compressor r vacuum pump

casing will withstand. These shall be at least equal to the values

calculated in accordance with NEMA SM -23. The allowable

forces and m oments shall be shown on the outline drawing.

2.5 Rotat ingElements

2.5.1 Rotating ssemblies shall bedesigned to be stiff

enough to prevent contact between the rotor and the casing

when perating at themaxim um llowable differential

pressure for all possibleoperatingconditions.Calculated

deflection of the haft at the eals shall notexceed

50

micrometers (0 .002 inches).

2.5.2

The imp eller shall be either secured to the shaft

by

an interference

fit

or ,keyed, and be capablef transmitting a

torque not less than 2.5 times that required for any specified

duty, and provided with an arrangem ent for positive axial

location.

2.5.3 Solid otors are preferred.Hollow otors will be

acceptable only if furnished in complianc e with one of the

requirements specified n 2.5.3.1 or 2.5.3.2.

2.5.3.1 The rotor is continuously self-venting.

2.5.3.2 The rotorsrovidedwithlug to allow

complete venting of any accumulated gas before beginning

any maintenance activity.

2.5.4 Shafts shall be m ade of one piece, forged steel or hot

rolledbar tock ndbe of ample ize to transmit he

maximum orque equiredunderany pecifiedoperating

conditions and to withstand continuously all stresses result-

ing from supported weights, thrusts, and starting, including

direct-on-line motor starting.

2.5.5

Shafts shall be providedwithenewablehaft

sleeves (that are removable without machining) in the sh aft

sealing areas. The sleeves shall be of wear-, co rrosion-, and

erosion-resistant material. Sleeves shall be ground and po l-

ished on their outside surface or finished for thepecific seal

application. Sleeves shall be positively located on the shaft

and shall be not less than 2.5 millimeters

O.

1 inches) thick.

2.5.6 With the purchaser’s approval, sleeves may be om it-

ted provided the proposal

so

states and the shaft

s

construct-

ed of an equivalent m aterial and has equal inish to that of a

sleeve. Shafts or stub shafts shall include centers to permit

refinishing.






LIQUID RING VACUUM PUMPS AND COM PRESSORS FOR

2.5.7 Forshafts hat equiresleevegaskets opassover

threads, the threads shall bet least 2 millimeters H6 inches)

less than the internal diameter f the gasket, and the diameter

transition shall be cham fered 15-20 degrees tovoid damage

to the gasket.

2.5.8 Shaft leeves hallbe ealed atoneend,and he

shaft-sleeve assembly shall extend at least 3 mill imeters

IA nches) beyond the outer facef the seal end plate. Lea k-

age between the shaft and th e sleeve thus can not be confused

with leak age throu gh the mechanical seal aces.

2.5.9 Shaftshall emachinednd properly finished

throughout heir ength so that here is no more than

25

microm eters 0.001 nches) otal ndicated un-ou t.Shaft

sleeves hallhave nomore than 50 micrometers (0.002

inches) total indicated run-out n the outside diameter.

2.6

Mechanical Shaf t

Seals

2.6.1

Mechan ical seals shall be furnished. When specified,

cartridge type seals shall be furnished.

2.6.2

The mech anical seal shall minimize leakage from or

into the vacuum pump or compressorver the entire range f

specifiedoperatingconditions,duringshut-down,start-up

and period s of idleness and shall also be suitable for opera-

tion of the machine on ir.

2.6.3 Seals hallwithstandhemaximum vacuum and

maximum allowable working pressure. Component parts of

the seals shall be suitable for the specified service conditions.

2.6.4

Where eal ace eakagemust becontained,dual

seals or single seals plus auxiliary shaft sealing devicesay

be specified by the purchaser. Venting, flushing, or blanket-

ing the space between the primary mechanical seal and the

auxiliary sealing device, or between mechanical seals, shall

be accomplished by means of tapped openings of the appro-

priate size but not less than NPS h,unless agreed to by the

purchaser. Thearrang emen t of seal fluid pipingshallbe

approved by the purchaser.

2.6.5 Sealshall eemovablewithoutemovinghe

vacuum pump or com pressor endousing, inlet or discharge

piping, or disturbing thedriver.

2.6.6 Mechan ical seal materials shall be proposed by the

vendor and approved by the purchaser.

2.6.7 The seal end plate component parts shallbe satisfac-

tory for at least the maximum design vacuum or m aximum

allowable working pressure and o perating temperature and

shallhave ufficient igidity to avoid anydistortion that

would imp air seal operation, including distortion that may

occur du ring tightening of the bolts to set gasketing. Provi-

PETROLEUM,HEMICAL,ND GAS INDUSTRYERVICES

9

shoulder shallbe provided to prevent axial movement of the

mechanical seal seat as a result of cham ber under or over

pressure. Seal end plate bolting shall be b ased on specified

operating emperature ndmaximum llowableworking

pressure and shall be in accordance w ith Section VIII, Divi-

sion I, of the

ASME

Code, except that no fewer than four

bolts shall be used.

2.6.8 Glandlateonnectionshall be identified by

stamping on the seal end plate the seal fluid inlet and outlet

and vent and drain connections. When required by seal de-

sign, directionof rotation shall be shownn each glandlate.

O 2.6.9 The vendor shall furnish all mechanical seal piping

and accessories as specified by the purchaser. See Ap pend ix

E

for typical seal flush plans.he seal piping system,nclud-

ingpipe,ubing , ittings,valves, trainers,orifices, and

separators, etc., shall be as specified in 3.7. The seal manu-

facturer and the vacuum pump or com pressor vendor shall

jointly establish the seal chamber circulation rate and shall

advise the purchaser of the condition required in the seal

chamber to ensure proper seal operation. In vacuum service,

the seal design shall be suitable to seal against atm ospheric

pressure w hen the pum p is not operating.

2.6.10

When specified for flamm able fluids, a non-spark-

ing throttle bushing shall be providedo minimize leakage in

the event of a co mplete seal failure. The diametral clearance

at the bushing bore shall not be mo re than 650 micrometers

(0.025 inches).

o 2.6.11 When pecifiedor equired, the ealglandplate

mating joint shall incorporate a fully confined gasket.

2.7

Dynamics

2.7.1

CRITICAL

SPEEDS

2.7.1.1 Critical speeds correspond to resonant frequencies

of the rotating assembly/bearing support system. The basic

identification of criticalspeeds s mad efrom he natural

frequencies of the system and the forcing p henom ena. If the

frequency of any harmonic component

of

a periodic forcing

phenomenon is equal to, or approx imates , the frequency of

any mod e of the rotating assembly vibration, a condition of

resonance may exist.f resonance exists at a finite sp eed,hat

speed is called a critical speed.

2.7.1.2 A rotor-bearing support system in resonance will

have its ormal ibration isplaceme ntmplified. The

magnitude of amplificationand he ate of phaseangle

change are related to the amount of damping in the system

and the m ode shape taken y the rotor.

be made for

centering lhe

end 'late

stuffing

Note: Lateral crltlcal speeds are not usually a matter of concern

for

liquid

box

bore

with either an inside diameter

Or

an outside diame-

nng com pressors and vacuum pumps, as thelr

first

lateral c n t d peed (dry)

ter regist er it.

A

minimum of 3-millimeter

O.

125-inch) thick

is

usually above

their

operating speed





API STDxbAL 96

0732290

0 5 5 0 b 2 7 7 T 2

10 API STANDARD 681

2.7.1.3 An exciting frequency may be less than, equal to,

or greater than the rotational speed of the rotating assembly.

Potential exciting frequencies that re to beonsidered in the

design of rotor-bearing systems shall nclude, but are not

limited to, the following sources:

a.

b.

d .

e .

f.

g.

C.

Unbalance in the rotating assembly system.

Internal rubs.

Blade or vane, passing frequencies.

Gear-tooth m eshing and side bands.

Coupling misalignment.

Loose rotating assembly system components.

Ball and race frequencies of antifriction bearings.

2.7.1.4 Resonance

of

structural upport may adversely

affect the rotor vibration amplitude. Resona nce of support

systems w ithin the ven dor’s sco pe of supply shall not occur

at the operating speed of a fixed speed machine or at any

speedwithinhe peratingange of a ariablepeed

machine.

2.7.1.5 Th e vendor who is specified to have unit responsi-

bility shall assure that the drive-train (turbine, gear, motor,

and the like) critical speeds (rotating assembly lateral, sys-

tem torsional, impeller blade mode s, and the like) will not

excite any critical speedof the m achinery being supplied and

that th e entire train is suitable for h e specified operating

speed range, including ny starting-speed detent (hold-point)

requirements of the rain.

A

list of all undesirable speeds

from zero to trip shall be subm itted

to

the purchaser for his

review ndncluded in thenstructionmanualor his

guidance.

2.7.1.6 Rotatingassemb lies hall be designed uch that

their first dry critical speed is at east 120 percent of the

maximum continuous or trip speed (whichevers greater).

Note Wet crltlcal speeds are not of

a

concern slnce they occur at speeds

higher than dry critical speeds.

2.7.1.7 When specified, the equipment vendor shall make

a lateral critical speed analysis

to

determine that the crltical

speeds of the driver and compressorhacuumpump are com-

patible and to assure acceptable amplitudes of vibration at

any speed rom ero to trip.Whenmutually greed o

between the vendor and pu rchaser,

a

typical lateral critical

speedanalysismaybeprovided or he electionbeing

offered.

2.7.1.8 Excitationsfndampedorsional natural

frequencics may come from many sources, w hich should e

considered in the analysis. These sources may include, but

are not limited to, the following:

a. Gear effects su ch as pitch line runout.

b. Start-up conditions such as speed detents (under inertial

impedances) and other torsional oscillations.

c. T orsional transients uch as start-ups of synchronous

electric motors.

d. Torsional excitation from drivers such as electric motors

and reciprocating engines.

e. Hydraulic governor and electronic feedback and control

loop resonances from variable-frequency motors.

f. Unbalance.

2.7.1.9 The undamped torsional natural frequencies of the

complete train shall be at least 10 percent above or 10 per-

cent belowany possible excitation frequency t the operating

speed of a fixed speed machin e or within the operating speed

range of a variable speed machine.

2.7.1.10 In addition omultiples of running speeds, tor-

sional excitations that arenot a function of operating speeds

or that are nonsynchronous in nature shall be considered in

the torsional analysis when applicable and shall be shown to

have no adverse effect. Identification of these frequencies

shall be the mutual responsibility of the purchaser and the

vendor.

2.7.1.1 1 When torsional resonances are calculated to fall

within the margin specifiedn 2.7.1.9, (and the purchaser and

vendor have agreed that all efforts to remo ve the critical from

within the limiting frequency range have been exhausted) a

stress analysis shall be performed o demonstrate hat he

resonances have no adverse effect on the complete rain. The

acceptance criteria for this analysis shall be mutually agreed

upon by the purcha ser an d the vendor.

2.7.1.12 When specified, he vendor shall perform a tor-

sional vibration analysis of the complete coupled train and

shall be responsible for directing the modifications necessary

to

meet the requirements of 2.7.1.8 through 2.7. l . 11.

2.7.2 VIBRATIONAND BALANCING

2.7.2.1 Rotating components shall be statically or dynam-

ically balanced

in

accordancewithendor’standard

requirements.

2.7.2.2 T he unfiltered vibra tionorllnti-friction

bearing vacuum pum ps and comp ressors, measured in any

direction on the bearing housing during he shop test and

field operation at rated speed and specified operating pres-

sures, shall not exceed the velocity or disp lacem ent values,

whichever are mo re restrictive, shown in Figure 2. Filtered

vibration hallbemeasured at running-speed requency,

vane passingrequency rrequencies,nd any other

frequencies specified by the purchaser.

2.7.2.3 When specified by the p urchaser, the vendor shall

demo nstrate that the vacuum pump or co mpresso r can oper-

ate at the quoted maximum and minimum pressure ratios and

capacity w ithout exceeding the limits specified n 2.7.2.2.






A P I

S T D * b B L 9 6 m 0732290 0550b28

639

m

LIQUID INGACUUMUMPSND OMPRESSORS FOR PETROLEUM, HEMICAL,NDGASNDUSTRY ERVICES

11

2.8

Bearings, Bearing Hou sings , and

Lubricat ion

2.8.1

BEARINGS

2.8.1.1

Bothadialndhrustearingshallehe

vendor’s standard antifriction design (ball or roller).

2.8.1.2 Antifrictionbearings hallbe elected o give a

minimum L,, life of

50,000

hours in continuous operation at

norm al o perating duty ut not

less

than

32,000

hours at max-

imum axial and radial loads and normal speed. (The

10

life

is the numb er of ho urs at the rated bearing load and speed

that 90 percent of

a

group of identical bearings will complete

or exceedbefore the first evidence of failure.)

2.8.1.3 Bearingsshallbesized orcontinuousoperation

underhemost dv erse pecified perating onditions.

Calculationsof he oadsshall nclude, but shall not be

limited to, the following factors:

a. Fo uling and variation in clearances up to twice th e des ign

internal clearances.

h. Step thrust from

all

diameter changes.

c. Stage differential pressure.

5.0

4.0

3.0

2.5

2.0

1 o

0 8

0.6

0.5

0.4

0 3

0.2

o.1

1

Pump speed (revolutions per minutes)

d. Variations in inlet and discharge pressure.

e. External loads from the driving equipment.

2.8.1.4 Thrustbearingsshall be arranged oallowaxial

positioning of each rotor relative o the casing and setting f

the bearings’ clearance or preload.

2.8.1.5 Antifriction bearings shall be retained

on

the shaft

and fitted into housings n accordan ce w ith the requirem ents

ofAFB MA Standard 7; however, the device used to lock ball

thrust bearings to the shaft shall e restricted b y a nut w ith a

tongue-type lock washer, for example, SeriesW.

2.8.1.6 Unlesstherwisepecifiedrequired,on-

angular ontact ype ntifrictionbearingswith AFBMA

symbol 3 internal clearances (C3) shall be provided.

Single or doub le ow bearings shall be of the Co nrad type

(no filling slots). Pumps or compressors using other than

3

clearance bearings shall have a stainless steel plate on each

bearing housing, clearly showing the bearing identification

and the AFB MA internal clearance symbol.

Note: Beanngs wi th AFBMA symbol

O

(normal) internal clearance

CO)

may be requlred to mamtain proper rotor axial position relative to the casing

to prevent metal to metal contact.

O0.2

Vibration velocity,

peak (inches per second)

Figure 2-Bearing-Housing Vibration Limits (Antifriction Bearings)





A P L

S T D J b A L

9 6

0732290 0550629

575

12 API STAh

2.8.2 BEARING HOUSINGS

2.8.2.1 Bearing ousings hall e quipped with laby-

rinth-type ealsor ip-type ealswhere he haftpasses

through the housing.

2.8.2.2 Bearinghousings orgrease ubricatedbearings

shall be provided with stainless steel pressure ype grease

fittings for filling w hile operating and a visible d ischarge p ort

for observing the displaced grease.

2.8.2.3 Where thegasor iquid s lammableor oxic,

cantileveredshaftsupportstructuresbolted osteelcases

shall also be steel.

2.8.2.4 When specified, bearing housings for o il-lubricat-

ed non-pressure-fed bearings shall be provided with tapped

and plugged

fill

and drain openings at least ‘/2 inch National

PipeThread NPT) in size.Tapeshallnot be applied to

threads of plugs nserted ntooilpassages. Th e housings

shall be equippedwithconstant-levelsight-feedoilersat

least 0.1 liter s (4 oun ces) n size, w ith a pos itive level posi-

tioner (not

a

set screw), heat resistant containers (not subject

to sunlight-or heat nd uced opacity or deterioration ), and

protective wire cages. When specified, the oilers shall meet

the purchaser’s preference. A permanent ndication of the

properoil evel hallbe ccurately ocated nd learly

marked on the outside of the bearing housing with perma-

nent metal ags,marks nscribed in thecastings or other

durable means.

2.8.2.5 Whenpecified,earingousingshall be

equippedwith eplaceableabyrinth-type nd eals nd

deflectors shall be provided. h e seals and deflectors shall be

made of nonspar king m aterials. The design of the seals an d

deflectors halleffectively etain oil in thehousingand

prevent entry of foreign material into the housing.

2.8.2.6 Wh en specified, rovisionshall be madeor

mountingoneradialvibration ransducer in eachbearing

hous ing. The ransducer location shall be as specified in API

Standard 670 (see 3.2.4.6).

2.8.2.7 When specified,hrustearingsndadial

bearings hall e ittedwith earing-metalemperature

sensors installed in accordance with API Standard70.

2.8.3UBRICATION

2.8.3.1 Unlessotherwisespecified,bearings and bearing

housings shall be arrang ed for grease lubrication.

2.8.3.2

When pecified,bearings ndbearinghousings

shall be arranged for h ydrocarbo n il lubrication.

2.8.3.3 Anypoints hat equiregrease ubrication hall

haveuitablextensionineso ermitccess uring

IDARD 681

2.8.3.4 When specified,provisions hall bemade for a

circulating or an oil mist system. The system design and

arrangement shall be agreed upon by the purchaser and the

vendor.

2.9 Materials

2.9.1ENERAL

2.9.1.1 Materials of construction shall be the manufactur-

er’s standard for the specified operating cond itions, except as

required or prohibited by the data sheets r this stan dard (see

3.7 for requirementsor piping material). ee Appendix F for

typical materials. The m etallurgy of all major compo nents

shall be clearly stated in the vendor’s pro posal.

2.9.1.2 Pressure etainingparts of machines hatare n

flammable or toxic services shall be steel.

2.9.1.3 Materials shall be dentified n he proposal with

theirapplicableASTM,AISI,ASME,or SAE’numbers,

including hematerialgrade seeAppendix F). Whenno

such designation s available, the vendor’s material specifica-

tion, giving physical properties, chemical composition, and

test requ iremen ts shall be included in the pr oposal.

2.9.1.4 The vendor shall specify the AS TM optional tests

and inspection procedures that may be necessary to ensure

that materials are satisfactory for the service.Such tests and

inspections shall be listed n he proposal. The purch aser

may considerspecifyingadditional estsand n spections,

especially ormaterialsused ncriticalcomponents see

5.2.3, Item i).

2.9.1.5 Minor parts hat are not dentified (such as nuts,

springs,washers,gaskets,andkeys)shall have corrosion

resistance at least equal o that of specified parts in the same

environment.

2.9.1.6 Th e purchaser will specify any corrosiveagents

present i n the gas and ring liquid and in the environm ent,

includingonstituents that mayausetressorrosion

cracking.

2.9.1.7 If parts exposed to conditions that promote inter-

granular corrosion are to be fabricated, hard faced, overlaid,

or repaired by welding, they shall be made of low carbon or

stabilized g rades of austenitic stainless s teels.

Note. Overlays or hard surfaces that contain more than

O . IO

percent carbon

can sensitize both low-carbon and stabilized grades

of

austenitlc stalnless

steel, unless a buffer layer that

is

not sensltw e to mtergranular

corrosion

IS

applied.

2.9.1.8 Where m ating parts such as studs and nuts of AISI

Standard Type 300 stainless steel or materials with similar

’ Society of Automotive Eng ineers, 400 Commonwealth Dnve, Warrendale,

operation.

Pennsyivania

15096.






LIQUID

RING

VACUUM UMPS NDCOMPRESSORS FOR PETROLEUM,CHEMICAL, ND GAS INDUSTRY ERVICES

13

galling tendencies are used, they shall be lubricated with an

antiseizure compound of the proper temperature specifica-

tion and be compatible with the gas.

Note. Torque loadin g values will be considerably different wlth and without

antlsemng compound.

2.9.1.9

Materials xposedo sour environment wet

H2S)

as defined by N ACE M R-0 1-75 shall be in accordance

with the requirements of that standard. Ferrous materials ot

covered by NACE MR -01- 75 shall be limited oa yield

strength not exceed ing 6 200 bar (90,0 00 pounds per square

inch) and

a

hard ness not exceeding Rockwell C22.

Compo nents hatare abricated by welding hallbe

post-weld heat treated, if required, so that both welds and

heat-affected zones meet the yield strength and hardness

requirements,Thepurch aser will specify on thedata

sheets the presen ce of H2S in the process gas.

e

2.9.1.10 When dissimilarmaterials with significantly

differentelectricalpotentialsareplaced in contact in the

presence of an electrolytic solution, galvanic couples hat

can result in serious corrosion of the less noble materialmay

be created. If su ch conditions exist, the purchaser and the

vendor should select materials in accordance with the NACE

Corrosion Engineer’s ReferenceBook.

2.9.1.1

1

Ma terials, casting factors, and the quality of any

welding shall be equal o hose required by Section VIII,

Division 1, of the ASM E Code. The manufacturer’sdata

repo rt form s, as pecified in the code, are not required.

2.9.1.12 Th e use of ASTM A 5 15 steel is prohibited. Low

carbon steels can be notch sensitive and susceptible to britlle

fracture atamb ient or low temperatures.Thercfore, only

fully killed, normalized steelsmad e to fine grain practice are

acceptable.

e 2.9.1.13 Copper andcopperalloys excludingMonelor

its equivalent, bearing babbitt, and precipitation hardened

stainless steels) shall not e used for parts of vacuum pum ps,

compressors or auxiliaries in contact with corrosive gas or

with gases capab le of form ing explosive copper compounds.

It will be the responsibility of the purchaser to note such gas

characteristics on the inquiry data sheets.

2.9.2 CASTINGS

2.9.2.1 Castin gs shall be sound and free from porosity, hot

tears, shrink holes, blow holes, cracks, scale, blisters, and

simila r injurious efects.Surface s of castings hall be

cleaned by san dblas ting, shotblasting, chemical cleaning, or

any other standard m ethod . Mold-parting fins and remains of

gates and risers shall be chipped, filed, or ground flush.

free (plating permitted) and

of

a composition compatible

with the casting.

2.9.2.3 Ferrous castings shall not b e repaired by w elding,

peening, plugging, burning in, or impregnating, exc ept as

specified in 2.9.2.3.1 and 2.9.2.3.2.

2.9.2.3.1 Weldable grades of steelastingsmay be

repaired by welding, using a qualified welding procedure

based on the requirements of Section VIII, Division 1 and

Section IX of the AS ME Code.

2.9.2.3.2 Cast gray iron or nodular iron may be repaired

by plugging within the limits specified in A ST M A 2 78, A

395, or A 536. The holes drilled for plugs shall be carefully

examined, using liquid penetrant, o ensur e that all defective

material has been removed. All repairs that are not covered

by ASTM specifications shall be subject to the purchaser’s

approval.

2.9.2.4 Fully enclosed cored voids, including voids closed

by plugging, are prohibited.

2.9.2.5

When specified, nodular iron castings shall be

produced in accordance with ASTM A 395. The production

of the castings shall also onform to he conditions specified

in

2.9.2.5.1 through 2.9.2.5.5.

2.9.2.5.1 Aminimum of oneet (threeamples) of

Charpy V-notch impact specim ens at one hird the thickness

of the test block shall be ma de fro m the aterial adjacent to

the tensile specimen on each keel

or

Y block. These speci-

mens shall have a minimum imp act value of 14.0 jou les (10

foot pounds) at room temperature.

2.9.2.5.2 The Keel o rY block cast at the end of the pour

shall be at least as thick as the thickest section of the main

casting.

2.9.2.5.3

Integrally cast test bosses, preferably at least 25

millimeters (1 inch) in height and diameter, shall be provided

for all critical areasof the casting for subs equen t emoval for

the purposes of hardness testing and microscopic examina-

tion. Critical reas are typicallyheavy ections, ection

changes, high stress points, flanges, and other points agreed

upon by the purchaserand the vendor. Classification of

graphite no dules shall be in accordance w ith AS TM A 24 7.

2.9.2.5.4 An as-cast sam ple rom ach ladle shall be

chemically analyzed.

2.9.2.5.5 Brinell hardness readings shall be ma de on the

actual casting at feasible locations including section hang es

and langes.Sufficientsurfacematerialshall be removed

beforehardness eadingsare mad e to elimin ate any skin

effect. Readings shall also be madeat the extremities of the

casting at locations that representhe section poured first and

2.9.2.2 Th e use of chaplets in pressure castings shall be

last. The se shall be made in addition to Brinell readings on

held to aminimum. The chapletshall be clean and corrosion

the keel or Y blocks.






A P I STDJhAL

96

m 0732290 0550b31 L23 m

14 API STANDARD

681

2.9.3

WELDING

2.9.3.1 Welding of piping and pressure containing parts,

as well as any d issimilar m etal welds a nd w eld repairs, sh all

be perform ed and nspected by personn el and procedures

qualified in accordan ce with Section VIII, Division 1 and

Section IX of the ASM E Code.

2.9.3.2 Th e vend or shall be respons ible for the review of

all repairs and repair welds to ensure that they are properly

heat reated and nondestructively examined for soundness

and compliance with the applicable qualified procedures (see

2.9. l . 1 1). Rep air welds s hall be nondestructively tested by

the same method used to detect the original law. As a mini-

mum, thenspection hall be y themagnetic article

method, in accordance with 4.2.2.4 for magnetic material

and by the iquidpenetrantmethod in accordancewith

4.2.2.5 for nonmagnetic material.

2.9.3.3 Unless otherw ise specified, all welding other than

that covered by Section VIII, Division1, of the ASME Code

andASME B31.3,suchaswelding on base-plates,non-

pressure ucting,agging, nd ontrol anels, hall be

performed in accordance with AWS D l. 1.

o

2.9.3.4

When sp ecified, pressure containing casings made

of wrought materials or combinations of wrought and cast

materialshallonform to theonditio ns specified in

2.9.3.4.1 through 2.9.3.4.4.

2.9.3.5.2 Auxiliarypipingwelded o hromium -molyb-

denum alloy steel or 12 percent chrome steel components

shall be of the same m aterial, except that chromium -molyb-

denum alloy steel pipe may be substituted for 12 percent

chrome steel pipe.

2.9.3.5.3 Whenheat reatment is required,pipingwelds

shall be made before the component is heat treated.

2.9.3.5.4 When pecified, roposed onnection esigns

shall be submitted to the purchaser for approval before fabri-

cation. The drawings shall show weld designs, size, m aterial,

and pre- and post-weld heat treatments.

2.9.3.5.5

Allwelds shallbe heat treated in accordance

with Section VIII, Division

1,

UW -10 and UW-40,

of

the

ASME Code.

o

2.9.4

LOW TEMPERATURE

For operating temperatures below30°C (-20°F) o r when

specified for other low ambient emperatures, steels shall

have, at the lowest specified temperature,n impact strength

sufficient toqualifyunder heminimumCharpy V-notch

impactenergy equirements of SectionVIII,Division 1,

UG-84, of the A SME code.or materials and thicknesses not

covered by the code, the purchaser will specify the require-

ments on the data sheets.

2.9.3.4.1

Platedgeshall be inspected by mag netic

particleor iquidpenetrant xamination s equired by Sec- 2.10 Nameplate and Rotation Arrows

tion VIII, Division 1, UG-93 (d)(3), of the ASM E Code.

2.1 0.1 A nameplate shall be securely attached a t a readily

2.9.3.4.2

Accessibleurfacesfweldshall be inspected

location

O n

the

equipment and On any Other major

by magneticparticleor iquidpenetrantexaminationafterpiece of auxiliaryequipment.

back chipping or gouging andagainafterpost-weldheat

treatment.

2.10.2 Rota t ion a rrows sha l l be cas t in o r a t tached to

each major i tem of rotat ing equipment a t a readily visi-

2.9.3.4.3 Pressure-containingwelds,ncluding welds of leocation.Nameplatesndotat ionrrowsif t-

the case to horizontal-ndertical-jointlanges, shall be tac he d)hall be oftandard Type 300

full-penetrationelds. steelrickel-copperlloyMonel or i tsquiva lent ) .

Attachment pins shal l be of the same m ateria l . Welding

2.9.3.4.4

Casingsfabricatedfrommaterials hat,accord-

ing to Section VIII, Division 1, of the ASM E code, require

post-weld heat treatment shall be heat treated regardless of

thickness.

o 2.9.3.5 When specified, connectionswelded opressure

casings shall be nstalled as specified in 2.9.3.5.1 hrough

2.9.3.5.5.

2.9.3.5.1 In addition o he equirem ents of 2.9.3.1, he

purchaser may specify that magn etic particle inspection or

liquid penetrant inspection of welds

is

required.

is not permitted.

o

2.10.3 Theurchaser’stemumber ,heendor’s

name, the machine’s se r ia l number , and the m achine’s

s ize and type , a s we l l as i t s minimum and maximum a l -

lowable design imits and rat ing data (including pres-

sures ,empera tures ,peeds ,ndower) ,ma x i mum

allowableworkingpressuresand emperatures,hydro-

stat ic test pressures, and cri t ical speeds, shal l appear on

the machine’s namepla te or da ta p la te . The purchase r

wil l specify on the data sheets whether customary or S I

units are to be shown.






LIQUIDRING ACUUM UMPS ND COMPRESSORS

FOR

PETROLEUM. HEMICAL.ND GAS INDUSTRY

SERVICES 15

SECTION 3-SYSTEM DESIGN

3.1 Ring

L iqu id

System

3.1.1 GENERAL

e 3.1.1.1 Unless therwisepecified,ystemhall e

furnished to supply the ring liquid

t

a suitable pressure and

temperature to the vacuum pumporcompressor.Typical

systemsare hown nAppendix D. The purchaser will

specify the system required.

Note: A liquid ring pump or compressor requlres

a

ring liqutd to operate.

Typically, the system requlred to provlde this llquld is furnished by the

vendor. The extent of the vendor’s scope of supply depends upon how the

vacuum pump

or

compressor is integrated into the user’s process.

3.1.1.2 Th e ring liquid system may include, but need not

be imited to the ollowingcomponents,as pecified or

required (see 3.1.2 through3.1.8):

a.

Separator to disengage the ring liquid from the discharge

gas stream . This sepa rator ay also serve as a storage v essel.

b. Cooler.

c. Strainer or filter.

d. Ring liquid pump.

e. Interconnecting piping.

f.Checkvalves.

g. Ring liquid purge system.

3.1.1.3 The ring liquid used shall be m utually agreedpon

by thepurchaserand he vendor. Purchaser will provide

composition and propertiesof the ring liquid.

3.1.1.4 Theystem shalleesignedoupplyhe

required quantity of ring liquid for all specified operating

conditions including start up and ”run-in”n air. The system

shall be designed and arranged to insure correct ring liquid

level during start-up and operation.

O 3.1.1.5 The purch aser will specify whether the ring liquid

components are to be mounted on the machine base or on a

separate skid.

3.1.1.6 Unless otherwise specified, the ring liquid system,

its arrangem ent (see 2.1.7), and controls shall be subject to

purchaser review.

e 3.1.1.7 Coolers, ilters,separators,drain raps,andother

pressure vessels within the scope

f

Section VIII, Division 1,

of the ASME Code shall conform to the code and,f specified

by the purchaser, shall be code stamped.

3.1.2 RING

LIQUID

SEPARATOR

O 3.1.2.1 If a separator s specified, t shall be designed o

separate the discharge gas rom the ring liquid. Vendor shall

advise the actual gasvelocity in the separator vapor space.

e 3.1.2.2 When specified, the vendor shall state the quantity

of

the ring iquid which will rema in entrained n he gas

delivered rom he eparator ateach specifiedoperating

condition. The purchaserwill pecifyany im itations

on

liquid carryover from the system.

Note: Translent conditions

such

as start-up and shutdown

may

cause unusu-

al carryover condltions.

e 3.1.2.3 When liquid-liquid separation is specified, the sys-

tem shall be designed to separate condensed process vapors

from the ring liquid and allow their removal. The purchaser

shall advise the separation time.

Note: Llquld-hquid separation is usually accomplished in a vessel designed

for

this purpose

or

In

the

same vessel used for liquid-gas separa tion.

3.1.2.4

Unlessotherwisespecified, an anti-vortexdevice

shall be installed in the draw-off nozzle for the ring liquid

that is recycled to the machine.

e

3.1.2.5 The purchaser will provide he vendor with suffi-

cient data to estimate the extent to which theapor may be

expected to condense within the machine. The vendor shall

account for this in the design of the machine and separator

and, if necessary,provide acilities for he emov al of

condensate. The purchaser will specify the pressure in the

system into which the condensate is toe discharged.

3.1.3RING LIQUID COOLER

3.1.3.1

Unlessotherwisespecified, hecoolershallbea

water-cooled, shell-and-tube type, with cooling water on the

tube side.

3.1.3.2 Unlesstherwisepecified,oolershalle

constructed and arranged to allow removal of the t ube bun-

dles without dismantling piping or machine components.

3.1.3.3 A rem ovable-bundle design is required for coolers

with mo re than 0.45 square m eters (5 square feet)f surface,

unless otherwise specified. Removable-bundle coolers shall

be in accordance w ith TEMA Class and shallbe construct-

ed with a removable channel cover. Tubes shall not have an

outside diameterof less than 15 millime.ters

(%

inch), and

the

tube wall shall not have hickness of less han1.25

millimeters

[18

BW G (0.0049 inch)]. U-bend tubes are not

permitted. Coolers shall be equipped with vent and drain

connections on their shell and tube sides.

3.1.3.4 Th e vendor shall include in the proposal complete

details of any proposed air-cooled heat exchanger.

e 3.1.3.5 When specified, water-cooled shell-and-tube cool-

ersshallbe designedandconstructed in accordance with

TEMA Class C or R, as specified. When TEMA Class R is





A P I

S T D * b A L

96

m

0732290

0 5 5 0 6 3 3 T T 6 m

16

API STA1VDARD 681

specified, the heat exchanger shall ben accordance withAPI

Standard 660.

3.1.4 RING LIQUID FILTER

3.1.4.1 Th e ring liquid system shall contain as a minimum

ay -ty pe strainer with a 40-mesh or finer) screen.

3.1.4.2 When p ecified,orwhen ecommended by the

vendor,a ing iquid filter shall be supplied,designed o

remove solid particles down to the stated size.

3.1.4.3 When specified, he filter shall be the replaceable

cartridge,duplex ypearranged oronline,uninterrupted

changeover.

3.1.5 RING LIQUID PUMPS

3.1.5.1

If aingiquid pum p is required,t hall be

centrifugal and n accordance with AN SI

B73.1

or B73.2,

unless otherwise specified.

3.1 S.2 The purc haser may specify a pump in accordance

with API 610.

3.1.6 RING LIQUID PIPING

3.1.6.1 Ring liquid piping shall be i n accordance with the

requirements of 3.7.

3.1.6.2 When specified by the purchaser, he vendor shall

make provision for manual

or

automatic makeup and drain-

ing of the ring liquid while the equipment

s

operating.

3.1.7 CHECK VALVES

3.1.7.1 A check v alve is required at the inlet to the vacuum

pump or compressor. Th e purchaser will specify if the valve

is to be provided y the vendor.

Note: Low-pressure-drop check valves

are

required for proper operatLon

of

the system.

3.1.7.2 Alternate designs, such as a quick acting isolating

valve activated on loss of driver power, may be provided as

mutually agreed upon by the purchaser and the endor.

a 3.1.7.3 When specified, the vendorhallrovide

discharge check valve and pressure reliefalve.

3.1.8 RING LIQUID PURGE SYSTEM

A ring liquid purge system shall be provided when speci-

fied or when required to reduce d issolved solids, gases,

or

conden sed vapors to an acceptable level.

3.2

Controlsand Inst rum entat ion

3.2.1 GENERAL

3.2.1.2 Unlessotherwise pecified, o ntrols nd nstru-

mentation shall be su itable for outdoo r installation.

3.2.1.3

Th e vendor hallprovide ufficientperformance

data for the acuum pump komp ressor to enable the purchas-

er todesign a control system for startup and or all specified

operating onditions.When pecified,he endor hall

review the purchaser’s overall control system for compatibil-

ity with vendor furnished control equipment.

3.2.2CONTROL SYSTEMS

3.2.2.1 Th e purchaser will specify he method of control,

the sourceof the control signal, its sensitivity and range, and

the equipm ent to be furnished by the vendor.

3.2.2.2 Unlesspecifiedtherwise,ontrolledecycle

bypass from discharge to suction is required. When speci-

fied, this shall be supplied by the vendor.

Note, Bypass control can be used for suction pressure control, start-up, and

pump protectlon from cavitation For ce rta ~n pplications,

a

vacuum relief

valve may be acceptable.

3.2.2.3

For

a variable-speed drive, the control signal shall

act oadjust he etpoint of thedriver’s peed-control

system. Unless otherwise specified, the control range shall

be from 105 percent

of

the speed required to maintain ring

liquid stability at hespecifiedcontrolparametercondi-

tions) to maximu m continuou s speed. Vendor sha ll advise

the minimum speed required to maintain ring liquid stability.

Note. A combmatlon

of

control modes may be requlred

on

dnves wlth

a

limlted speed range and on m ultlservlce o r multlstream appllcatlons.

3.2.2.4 For ariable-speed rive,he quipment nd

control ystem hallbeequippedwith an overspeed rip

device independent of the sp eed co ntrol sy stem.

3.2.2.5 Th e full range of the specified control signal shall

correspond o he equiredoperating ange of thedriven

equipment. Unless otherwise specified, the maximum con-

trol signal hallcorrespond o hemaximumcontinuous

speed or the maxim um flow.

3.2.2.6 Actuation of the control signalor failure of the sig-

nal or actuator shall neither prevent the speed control system

from limiting the speed to the maxim um continuous speed

nor prevent manual regulation with the hand speed changer.

3.2.3 NSTRUMENT AND CONTROL PANELS

3.2.3.1 When pecified, anel hall be provided nd

shall include all pan el-moun ted instrumen ts for the driven

equipment and thedriver. Such panels shall be designed and





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A P I S T D * b L 9 6 m 0732290 O550634 932

LIQUIDRING ACUUM UMPS NDCOMPRESSORS FOR PETROLEUM,CHEMICAL, ND GAS INDUSTRY ERVICES 17

fabricatedn ccordancewithhepurchase r’s pecification. 3.2.4.4 Thermocoup les and Resistance

Theurchaser willpecifyhetherheanelsoeree- Temperature Detectors

standing, located on the baseof the unit, or in another loca-

tion, The instruments on the panel shall be clearly visible to

the operator from the driver control point.

A

lamp test push

button shall be provided. The instruments tobe mounted on

the panel shall be specified on the data sheets.

Wherepractical, hedesignand ocation of thermo-

couplesandresistance emperaturedetectorsshallpermit

replacement while the unit is operating. Th e lead wires of

thermocouples and resistance temperature detectors shallbe

installedascontinuous eadsbetween the hermowellor

3.2.3.2 Panels hall be com pletely ssembled, equiringdetector nd he erminalbox.Conduit uns from hermo-

only connection o hepurchaser’sexternalpipingandcoupleheads to apullboxorboxes ocatedon thebaseplate

wiring circuits. When mo re than one wiring point is required shall be provided.

on a unit for control or instrum entation, the wiring to each

switch or instrument shall be provided from a single terminal 3.2.4.5 Pressure Gauges

box with terminal posts, mounted on the unit (or its base,f

any).Wiringhall be installed in metalonduitsrnclo-

shall be furnished with

Type

316 steel Bourdon

ressure gauges (excluding built-in instrument

ir

gauges)

sures.All eadsandposts on terminal trips, witches,and ubesand stainless steel movements, llO-millimeter 41/2-

instruments shall be tagged for identification.

inch) dials and NPS %-inch male alloy steel connections.

Black printing on a white background

s

standard for gauges.

3.2.4NSTRUMENTATION Whenpecified,iquid-filledaugeshall be furnishedn

locations subject to vibration.Gauge ranges shall preferably

3.2.4.1 Minimum Instrumentation

be selected so that the normal operating pressure is in the

middle third of the gaug e’s range. In no case, owever, shall

Vendor shall submit his recommendations for instrumen- the maximum reading on the dial be less than the applicable

tation to ensu re safe and reliabl e operation. The follow ing, as relief valve setting plus 10 percent. Each pressure gauge

a minimum,shallbe ncluded.Refer oAppendix D. shallbeprovidedwithadevicesuch as adisc nsert or blow-

a.

b.

d.

e.

f.

C.

~~

out back designed to relieve excess ase pressure.

3.2.4.6 Vibration Detectors

Gas inlet pressure.

Gas inlet temperature.

Ring liquidgas outlet pressure.

Ring l iqu idgas outletemperature.

O

3.2.4.6.1 Whenpecified,ccelerometershall be

Ringiquidupplyemperature.upplied,nstalled,ndalibrated

in

accordanceithPI

Ringiquid level in separatornotequiredor ncc- tandard 70.

through or partial recirculation systems).

g. Ring liquid supply pressure, or flow.

3.2.4.2 Temperature Gauges

3.2.4.2.1 Dial-typeempera ture auges hall be heavy

duty and corrosion resistant. They shall be at least25 milli-

meters

(5

inches) in diameter and bim etallic type or liquid

filled. Black printing on a white background is standard for

gauges.

3.2.4.2.2

The ensing lements of temperature auges

shall be in the flowing fluid.

Note:

Thls 1s

particularly u nportant for lmes

that

may run par t~al lyull

3.2.4.3 Thermowells

O 3.2.4.6.2 Whenpecified,monitorshall be supplied,

installed, and calibrated n accordance with API Standard

670.

3.2.4.7 Solenoid Valves

3.2.4.7.1 Direct olenoid-operatedvalves hall be used

only in clean, dry instrument-air service, shall have Class

F

insulationorbetter,and hallhaveacontinuous ervice

rating. When required for other services, the solenoid shall

act as a pilot valve.

3.2.4.7.2 Solenoid valves shall not be us ed in continuou s

services that may affectnormaloperations.Theymay be

used

in

intermittent instrument services.

3.2.4.8 Pressure ReliefValves

Temperature sensing devices that aren contact with flam-

3.2.4.8.1 The vendor shall furnish the relief valves that are

mable or toxic fluids or that are located in pressurized or

to be installed on equipm ent or in piping that the vendor is

flooded lines shall be furnished with

NPS

)/4 AIS1 Standard

supplyin g Other relief v alves will be furnished by the pur-

Type 300 stainless steel separable solid-bar thermowells.

chaser. Relief valves for all operating equipment shall meet






A P I S T D * b L 96 0732290 0550635

8 7 9

m

18 API STANDARD 681

the limiting relief valve requirements defined in API Recom-

mended Practice 520, Parts I and II, and in API Standard 526.

The vend or shall determin e the size and set pressure of all

relief valves related to the equipmen t for the purchaser’s

approv al. Th e vendor’s quotation shall list all relief valves

and shall clearly indicate thoseo be furnishedby the vendor.

Relief valve settings, including accumulation, shall take into

consideration all possible typesof equipment failure and the

protection of piping systems (see5.2.3, Item j).

3.2.4.8.2 Unlessothe rwis e pecifi ed, relief valves shall

have steel bodies.

3.2.4.8.3 Whe n pecified, herm al relief valves shall be

provided for com ponents that m ay be blockedn by isolation

valves.

3.2.5ALARMSANDSHUTDOWNS

3.2.5.1 General

Switches, control devices, and annunciator display units

shall be furnished and moun ted by the vendor as specified

and may include those listed below. Th e alarm setting shall

precede the shutdown setting.

a. High gas ou tlet temperature.

b. High gas outlet pressure.

c. High ring liquid outlet temperature.

d. Low ring liquid flow.

e. Low ring liquid level in separator.

f. High ring liquid level separator.

g.

High bearing hou sing vibration.

h. Low m echanical seal fluid pressure.

3.2.5.2 Annunciator

The vendor shall furnish a first-out annunciator when an

annunciatorystemspecified.The nnunciatorhall

contain approxim ately 25 percent spare points and, when

specified, shall be arranged for purging. Connections shall be

provided for actuation of a remote signal when ny function

alarmsor rips. The equen ce of operation hallbe s

specified in 3.2.5.2.1 through 3.2.5.2.3.

3.2.5.2.1

Alarm indication shall consist of the flashing

of

a light and the soundingof an audible device.

3.2.5.2.2 The alarm cond ition shall be acknowledged by

operating an alarm-silencing button comm on to all alarm

functions.

3.2.5.2.3 When healarm is acknowledged, heaudible

device shall be silenced,ut the light shall remain steadily lit

as long as the alarm condition exists. Th e annunciator shall

be capable of indicating a new alarm (with a flashing light

andsoundinghorn) if another unction eaches an alarm

condition, even if the previousalarmconditionhasbeen

acknowledged but still exists.

3.2.5.3 Alarm and Trip Switches

3.2.5.3.1

Eachalarm witchand each hutdown witch

shall be furnished in a separate housing located to facilitate

inspectionandmaintenance.Hermetically ealed, ingle-

pole, double-throw switches with

a

minimum capacity of 5

amperes at 120volts

AC

and

1 2

ampere at 120 voltsDC hall

be used. Mercury switches shall not be used.

3.2.5.3.2 Unless therwisepecified,lectricwitches

that open (de-energize) to alarm and close (en ergize) to trip

shall be furnished by the vendor.

3.2.5.3.3 Alarm ndripwitchettingshall not be

adjustable from outside the housing. Alarm and trip switches

shall be arranged o permit esting of the control circuit,

including , when possible, heactuatingelement,without

interferingwithnormaloperation of theequipment.The

vendor shall provide a clearly visible light

on

the panel to

indicate when trip circuits are n a test bypass mode. Unless

otherwise pecified, hutdown ystems hallbeprovided

with switches or another suitable means o permit esting

without shutting down the unit.

3.2.5.3.4 The vendor hall urnishwith heproposala

complete description of the alarm and sh utdow n facilities to

be provided (see 5.2.3, Item).

3.2.5.3.5

Pressure-sensing elements shall be ofAISI Stan-

dard Type 300 stainless steel. Low pressure alarms, which

are activated by falling pressure, shall be equip ped with a

valved bleed or vent connection to allow co ntrolled depres-

surizing

so

that the operator can note the alarm set pressure

on theassociatedpressuregauge.Highpressurealarms,

which are activatedby risingpressure,shallbe equipped

with valved test connections so that

a

portable test pump can

be used to raise the pressure.

o

3.2.5.4 Replacement of Instruments and Controls

When specified, all instrumen ts and controls other than

shutdown sensing devices shall be installed with sufficient

valving to permit their replacement while the system is in

operation. When shutoff valves are specified for shutdow n

sensing devices, the vendor shall provide aeans of locking

the valves in the open position.

3.2.5.5 Housings for Arcing-Type Switches

Particular attention is called to the requirements of 2.1.8

concerning he characteristics of housings for arcing-type

switches outlined in the applicable codes.





API STD*b&L

96

0732290 0 5 5 0 6 3 6

7 0 5 W

LIQUID

RING

VACUUM UMPS NDCOMPRESSORS

FOR

PETROLEUM,CHEMICAL, ND GAS INDUSTRY ERVICES

19

3.2.6

ELECTRICAL SYSTEMS

3.2.6.1

The characteristicsof electrical power supp lies for

motors, heaters, and nstrumentation shall be specified. A

pilot light shall be provided on the incoming side of each

supply circuit to indicate that the circuit is energized. The

pilot lights shall be installed n the c ontrol p anels.

3.2.6.2

Electrical equipment located on the

uni t

or on any

separate panel shall be suitable for the hazard classification

specified. Electrical starting and supervisory controlsay be

either

AC

or DC.

3.2.6.3

Powerandcontrolwiringwithin heconfines

of

the baseplate shall be resistant o oil, heat, moisture, and

abrasion. Stran ded con ductors shall be used within the con-

fines of the baseplate and n other areas subject to vibra tion.

Mea surement and rem ote-control panel w iringmay be solid

conductor. Thermoplastic insulation shall be used and shall

becovered by aNeopreneorequalsheath orabrasion

protection. Wiring shall be suitable for the environmen tal

temperatures specified.

19-millimeter %-inch)bronzehosewith our-wall nter-

locking construction and joints with packed-on (heatproof)

couplings shall be used.

3.2.6.8

For Division

2

locations, flexible metallic conduits

shall have a liquid tight thermosetting or thermoplastic outer

jacket and approvedfittings.ForDivision1 ocations, an

NFPA-approved connector shall be provided.

3.2.6.9 AC and DC circuitshall e learlyabeled,

connected oseparate erminalblocks,and solated rom

each other.

3.3

Drivers and Transm issions

3.3.1 The type of driver shall be specified. T he driver sha ll

be sized to meet the maxim um specified operating condi-

tions, including exte rnal transm ission losses, nd shall be

n

accordance with applicable specifications, as statedn the in-

quiry and order. The driver shall be suitable for satisfactory

operation under the utility and site conditions specified by

the purchaser.

3.2.6.6 Electrical materials, ncluding nsulation, shall be

corrosion resistant and non-hyg roscopic insofar as is p ossi-

ble. When specified for tropical location, materials shall be

given the treatments specified in 3.5.6.6.1 and 3.5.6.6.2.

3.2.6.6.1 Partssuch s oils ndwindings)hall be

protected from fungus attack.

3.2.6.6.2 Unpaintedurfaceshall be protectedrom

corrosion by plating or another suitable coating.

3.2.6.7

Control,nstrumentation,ndoweriring

(including temperature element leads) within the confinesf

the baseplate shall be installedn rigid metallic conduits nd

boxes, properly bracketed to minimize vibration, and isolat-

ed or shielded to prevent interference between voltage levels.

Condu its m ay terminate (and n the case of tempera ture ele-

ment heads, shall terminate) with a flexible metallic conduit

long enough to permit access to the unit for maintenance

without removal of the conduit.

f

temperature element heads

willbeexuosed o emneraturesabove60°C 140 F), a

suction at atmospheric pressure.

3.3.4

For motor driven units, the motor nameplate rating

(exclusive of the service factor) shallbe at least 110 percent

of themaximum owerequiredincluding earnd

coupling losses) for any of the specified operating condi-

tions. Conside ration shall be given ostartingconditions.

Equipment driven by induction motors shall be rated at the

actual motor speed for the rated load condition.

o 3.3.5

In thecase of electricmotordrives, hepurchaser

will specify he ype of m otor and ts characteristics and

accessories, including the following:

a. Electrical characteristics.

b. Starting conditions (including the expected voltage drop

on starting).

c. Type of enclosure.

d. Maximum allowable sound pressure level.

e. Area classification.

f.

Type of insulation.




~-

~

~~

A P I STD*b8L

96

m 0732290 0550637

bYL

m

20 API STA1

NDARD 681

g. Required service factor.

h. Ambient temperature and elevation above sea level.

i. Transmission osses.

j. Temp erature detectors, vibration sensors, and heaters, if

these

are

required.

k.Auxiliaries suchas

a

ventilationblower nd nstru-

mentation).

3.3.6 Themotor’s tarting-torque equirements hall be

me t at a specified reduced voltage, and the m otor shall accel-

erate to full speedithin a periodof time agreed upon y the

purchaser and the vendor.

Note: For most applications, the starting voltage is typlcally

80

percent of

the normal voltage, and the time requlred to accelerate to full speed is

generally less than

15

seconds.

3.3.7 Steam urbinedrivers hallconform o API

61

1.

Steam turb ine drivers shall b e sized to deliver continuously

110percent of the maximum ower required for the purchas-

er’s specified conditions while operating at a co rresponding

speed of the specified steam conditions. Co nsideration shall

be given to starting conditions.

3.3.8 Gears shall conform to A PI Standard 677.

3.3.9 For drivers hatweighmore han 450 kilograms

(1000 pounds), the driver feet shalle provided with vertical

jackscrews.

3.4

Coupl ingsand

Guards

3.4.1

Unlessotherwise pecified, lexible ouplings n d

guards etween rivers nd riven quipment hall e

supplied by the manufacturer of the driven equipment.

3.4.2 Couplinghubs hall be steel.Flexible-discypes

shall have discs of corrosion-resistant material. The m ake,

model, materials, service factor, and m ounting arrangement

of couplings w ill be specified by the purchaser. A spacer

coupling shall be used unless otherwise specified. The spacer

shallhaveanomin al ength of at least

125

millimeters

5

inches) ndhall ermitemoval of the oupling,

bearings,and ealswithoutdisturbing hedriver or the

suction and discharge piping.

Note: When flexible-element couplingsre specified, consideration

should

be given

to

designs that will retain the spacer if

a

flexible element

ruptures.

3.4.3 Information on shafts, keyway dimensions (if any),

and shaft end movements due to end play and thermal effects

shall

be

furnished to the endor supplying the coupling.

3.4.4 Couplingsandcoupling-to-shaft uncturesshall

be

rated for at least the m axim um driver power, including any

motor service factor.

3.4.5 Couplingsshallbe keyed.Keys,keyways,andfits

shallconform oAGMA 9002. Couplinghubs hall be

furnished with tapped puller holes at least % inch (10 milli-

meters) in size to aid removal.

3.4.6 When specified, the coupling surfaces normally used

for checking alignment shall be concentric with the axis of

coupling ubotationwithinheollowingimits:

0.5

microm eters total indicated runout per millimeter of shaft

diameter (0.0005 inch per inch), with a maximum

of

100

micrometers (0.003 inches) total indicated runout. All other

diameters not used for location, registration, or alignm ent

shall be to the coupling manufacturer’s standard, provided

balance requirements are met.

O

3.4.7 When specified, couplings shall be manufactured o

meet he balance requirements of

AGMA

9000, Class 8.

When specified by the purchaser or recomm ended by the

vendor, couplings shall be dynam ically balanced in accor-

dance withAGMA 9000.

For

dynamic balancing, the AGMA

balance class shall be mutually agreed upony the purchaser

and the vendor.

3.4.8 Whenpecified,imited-end-floatouplingswith

maximum coupling end floats as specified

n

Table 3 shallbe

suppliedwithhorizontal-sleeve-bearing motors oprevent

the motor rotor from rubbing stationary motor parts.

Note: Couplings with

axial

elastic centering forces

are

usually satisfactory

without these precautions.

3.4.9 When the vendor is not required to m ount the driver,

he shall deliver the fully machined half-coupling to the driver

manufacturer’s lant or any other esignatedocation,

together with he necessary nstructions for mounting he

half-coupling on the driver shaft.

3.4.10 Removable coupling guards shall be furnished and

shallbe in accordancewith heOccupationalSafetyand

Health Adm inistration’s requirements for coupling guards.

3.5BeltDrives

3.5.1 Belt drives shall only be used for equipmen t of 150

kilowatts (200 brake horsepower) or less and, un less other-

wisespecified,shallemploymultiple-Vbelts or positive

drive belts. Multiple V-belts shallbe urnished in either

matched setsor banded multi-V designs. All belts shall be oil

resistant (that is, they shall have a core of Neo pren e or an

equivalentmaterial)andshallbe of the static-conducting

type. The service factor shall not e less than 1.75 times the

driver nameplate power rating.

Table

3-Maximum Coupling

End

Floats

Minimum Motor

Rotor

Max lmum

Coupling

End

Float

End

Float

Millimeters

Inches Mllhmeters Inches

6

O 250 2

0.090

13

0.500

5

O 190





LIQUID RIN G VACUUMUMPSND OMPRESSORS FOR PETROLEUM, HEMICAL,ND GAS INDUSTRYERVICES 21

3.5.2 Th e vendor shall provide a positive belt-tensioning

deviceonallbeltdrives. This deviceshall ncorporatea

lateral adjustable base with guides and hold-down bolts, two

belt-tensioning screws, and locking bolts.

3.5.3

Th e vendor wh o has unit responsibility shall inform

the m anufacturer of the connected equipm ent when a belt

drive is to e used. Th e driver manufacturer shall e provided

with the belt drive’s radial-load. These characteristics shall

be taken into account w hen the driver s selected.

3.5.4 Beltdrivesshall meet the equirements of 3.5.4.1

through 3.5.4.7.

3.5.4.1

Thedistan ce between hecenters of thesheaves

shall not be ess han

1.5

times he diameter of the arge

sheave.

3.5.4.2 Th e belt wrap (contact) angle on the small sheave

shall not be less than

140

degrees.

3.5.4.3 The sh aft length on w hich the sheave hub is fitted

shall be greater than or equalo the width of the shea ve hub.

3.5.4.4 The length of

a

shaft key fitting used to mou nt a

sheave shall not be less than the lengthf the sheave bore.

3.5.4.5 The shea ve shall be m ounted on a tapered adapter

bushing.

3.5.4.6 To reduce bearing mom ent loading (belt tension),

the sheave overhang distance shall be minimized.

3.5.4.7 Wh en specified, heaves hallmeet hebalance

requirements of

ANSI

S2.19, Grade6.3.

3.5.5 Removable guards shall be furnished and shall be in

accordance with the Occupational Safety and Health Admin-

istrations requirements for guards.

3.6 Mounting Plates

3.6.1 GENERAL

3.6.1.1 The eq uipm ent shall be furnished with soleplate or

a baseplate as specified on the data sheets. The vendor shall

mount and align the driver and transmissionn the mounting

plate prior o shipment. The purchaser will specify either

continuously grouted or column mounting (see 3.6.1.2.4 and

3.6.2.4).

3.6.1.2 In 3.6.1.2.1 through 3.6.1.2.1 1, the term

mounting

plate refers to both baseplate and soleplates.

3.6.1.2.1 Th e upper surfaces of mounting plates used for

mounting heequipmentshallbe machinedparallel.The

maximum surface finish shall be 3 micrometers

125

micro-

inches) Ra.

3.6.1.2.2

Mou nting plates shall be equipped with vertical

jackscrews.

3.6.1 -2.3 Unless otherwise specified, alignment position-

ing screws shall be provided for each driver and gearbox that

weighs 225 kg

500

lb) or mo re o facilitate longitud inal an d

transversehorizontaladjustment. Th e ugs holding hese

jackscrews shall be attached

to

the mounting plates so that

they d o not interfere with th e installation o r rem oval of the

drive element or shim s.

3.6.1.2.4 Machinery supports shall be designed to limit a

change of alignment to50 micrometers (0.002 inches) at the

coupling flange, in addition o that allowed in

2 2 4

(see 2.4

for allowable piping forces).

3.6.1.2.5

When epo xy grout is specified, the vendor shall

commercially sandblast, in accordance with SSPC SP 6, all

the grouting surfaces of the mounting plates and shall pre-

coat these surfaces with a catalyzed epoxy primer.he epoxy

primer shall be compa tible with epoxy grout. The vendor

shall submit to the purchaser instructions for field prepara-

tion of the epoxy primer.

Note: Epoxy primers have a limited

life

after applicatlon. Thegrout

manufacturer should

be

consulted to ensure proper field preparation of the

mountlng plate for satisfactory bo nding of the grout.

3.6.1.2.6 Anch or bo lts shall not be used to fasten machin-

ery to the mounting plates.

3.6.1.2.7 Mou nting plates shall not be drilled for equip-

ment to be mounted by others. The outsid e corn ers of the

mounting p lates in contact with the grout shall have at least

50

millimeters ( 2 inch) radii in the plan view.

3.6.1.2.8 Machinedmountingurfaceshall xtend at

least 25 millimeters (1 inch) beyond the outer three sides of

equipment feet

to

facilitate alignment at installation.

3.6.1.2.9 All padsor rivers nd earboxes hall be

machine d to allow for the installation f shims at least m il-

limeters (% inch) hick under each comp onent. Wh en the

vendor mounts the components, a setf stainless steel shims

at least 3 millimeters

Y

inch) thick shall be furnished. All

shimpacks shall straddle heholddownboltsand any

vertical jackscrew s.

3.6.1.2.10 Anc hor o l t swi l l e u rn i she d y h e

purc ha se r .

3.6.2 BASEPLATE

3.6.2.1 When a baseplate or skid s pecified, he data

sheets will indicate the major equipment items to be mount-

ed on it.A baseplate shall be a single unit f fabricated steel

construction.

3.6.2.2 Unless therwisepecified,he aseplatehall

extend un der the pum p, driver, and gear.

3.6.2.3 Whenpecified,aseplatesrkidshall be

provided with levelling pads or targets protected by remov-






22 API STANDARD 681

able covers. The pads or targets hall be accessible or field 3 7

Pip ing

levelling after installation, with the equip men tmounted and

the

3.7.1

GENERAL

3.6.2.4 When column mounting is specified, the baseplate

shall be of sufficient rigidity to be suppo rted at the specified

pointswithoutontinuousroutingndertructural 3.7.1 -2 Piping systems are defined as f o ~ ~ o w s:

members. The baseplatedesignshall be mutually agreed

upon by the purchaser and the vendor.

3.7.1.1 Pipingdesign and joint fabrication,examination,

and inspection shall be

in

accordance with ANSI B31.3.

a. Group I:

l . Vapor piping.

3.6.2.5 Unless otherw ise pecified, fabricated baseplates

shall be designed in accordance with AISC Manual of Steel

Construction, Part

5 ,

Specifications and Codes.

3.6.2.6

Single-piecerain-rimrrain-panaseplates

shall be furnished. Th e rim or pan of the baseplate shall be

sloped a t least

1:120

toward the pum p end , where a tapped

drain opening at least

1

inch NP T in size shall be located to

affect complete drainage.

As

a m ínim um, the drain-rim or

drain-pan shall extend underneath the pump or compressor

to collect leakage. When specified, more extensive leakage

collection shall be provided.

3.6.2.7 The baseplateshall be provid ed with lifting lug s

for at least a four-po int lift. Lifting the baseplate comp lete

with all equip men t mounted shall not permanently distort or

otherwise dam age the baseplate or machinery mounted on it.

3.6.2.8 The bottom of the baseplate between structural

members shall be open. When the baseplate is installed on a

concrete foun dation , it shall be provided with at least one

grout hole having

a

clear area of at least 100 square centi-

meters (19 squar e inches) and no dimension less than 75 mil-

limeters (3 inches) in each bulkhead section. These holes

shall be located to permit grouting under all load-carry ing

structural membe rs. Wh ere practical, holes shall be accessi-

ble for grouting with equipment nstalled. The holes shall

have 13-millimeter (%-inc h) raised-lip ed ges, and if located

in

an area where liquids could impinge n the exposed grout,

metallic covers with a minimum thickness of

16

gauge shall

be provided. Vent holes at least

13

millimeters

S

nch)

in

size shall be provided a t the highest point in each bulkhead

section of the baseplate.

3.6.2.9 When specified, mounting pads on the bottom of

the baseplate shall be provided and shall be in o ne plane to

permit u se of a single-level f ounda tion.

2. Ring liquid.

3. Mech anical seal flushing fluid.

4. Drains and vents.

b. Group II:

l . Cooling water.

2.

Cooling water drains and vents.

3. Instrument air.

Systems shall comply with the requirements of Table 4.

Note:

Casing

connections are discussed I n 2.3

3.7.1.3 Piping systems shallncludeiping,solating

valves, control valves, relief valves, pressure reducers, ori-

fices, temperature gauges and thermowells, pressure gauges,

sight flow indicators, and all related vents and drains.

3.7.1.4 The vendor shall furnish all pipingystems,

including mounted appurtenances, located within the con-

fines of the main unit's base area, or any auxiliary base area.

Th e piping sha ll terminate with flanged co nnections at the

edge of the base. Th e purchaser will furnish only intercon-

necting piping between equip men t groupings and off-base

facilities (s ee 3.7.2.2).

3.7.1.5

The design of piping systems shallachieve the

following:

a. Proper support and protection o prevent damage from

vibration or from shipment, operation, and maintenance.

b. Proper flexibility and norm al accessibility for operation ,

maintenance, and thorough cleaning.

c. Installation in a neat and orderly arrangem ent adapted to

the contour of the machine without obstruction of access

openings.

d. Elimination

of

air pockets by the use of valved vents or

nonaccumulating piping arrangements.

e. Complete drainage through

low

points without disassem-

bly of piping.

3.7.1.6 Th e use of flanges and fittings shall be minimized.

-

3.6.2.1O Wh en specified, nonskid metal decking covering Piping shall preferably be fabricated by bending and weldin g

all walk and work areas shall be provided on baseplate top. to minim ize he use of flanges and fittings. Welde d flanges

are permitted only at equip men t connections, at the edg e of

3.6.2.1 1 Whenspecifie d, the baseplatemountingpads any base, and for ease of maintenance. Th e use of flanges at

shall be machined fter the baseplatesabricated. ther oints is permitted only with the purchaser's specific





API S T D x b d L 96 0732290 0550640 L36 m

LIQUIDRING ACUUM UMPS NDCOMPRESSORS

FOR

PETROLEUM.CHEMICAL. NDGASNDUSTRY ERVICES

23

approval. Othe r than tees and reducers, welded fittings are

permitted only to facilitate pipe layout in congested areas.

Pipe bushings shall not be used. Threaded connections shall

be held to a minimum.

3.7.1.7

Pipe hre ads shall be taper hreads n accordance

with ASME

B

1.20.1. Flanges shall be n accordance with

ANSI B 16.5. Slip-on flanges are permitted only with he

purchaser’sspecificapproval.Unlessotherwisespecified,

for socket-welded construction , a 1.6-millimeter (%-inch)

gap shall be left between the pipe end and the bottom f the

socket.

3.7.1.8 Connections,piping,valves,and ittings hatare

30millimeters (1% inches), 65 millimeters (2% inches), 90

millimeters (3% inches), 125 millimeters 5 inches), 175 mil-

limeters (7 inches), or 225 millimeters

9

inches) in size shall

not be used.

3.7.1.9

Where space does not permit the use of

NPS

Yi

Yi,

or 1 pipe, seamless tubing may be furnished in accor-

dance with Table . The make and model ofittings shall be

subject to purchaser’s approval.

3.7.1.10 Theminimumsize of any conne ctionshall be

NPS % nominal pipe size.

3.7.1.1 1 Piping systems furnished by the vendor shall be

fabricated, nstalled n heshop, and properlysupported.

Bolt olesor langed onn ections hall traddleines

parallel to the main horizon tal or vertical centerline of the

equipment.

3.7.1.12

Welding hallbeperformed by operators nd

procedures qualified in accordance with Section IX of the

ASME code.

3.7.1.1 3 Pipe plugs shall be in accorda nce with 2.3.7.

3.7.1.14 Thextent of andequirementsor rocess

piping to be supplied by the vendor shall be specified.

O 3.7.1.1 5 When pecified,he end or halleview all

piping,appurtenances,andvessels mm ediatelyupstream

and ownstream of thequipmentndupports.The

purchaser and the vendor shall mu tually agree on the scope

of this review.

3.7.2 INSTRUMENT PIPING

3.7.2.1 The vendorhallupply

all

necessary iping,

valves, and fittings for nstruments and nstrumen t panels

(see 3.2.3.2).

3.7.2.2 Connections on equipment and piping for pressure

instruments and test points shall con form to .7.1.4. Beyon d

the initial % -inch isolating valve, NPS % piping, valves, and

fittings may be used. Where convenient, acommon connec-

tion m ay b e used for emotelymounted nstruments hat

measurehe amepressure.Separate econdary %-inch

isolating valves are required for each instrument on a com-

mon connection. Where a pressure gauge is to be used for

testing ressure larm or hutdown witches, omm on

connections are required for pressuregauge and switches.

3.8

Special Tools

3.8.1 Whenpecialools ndixtures reequired to

disassemb le, assemb le, or maintain he unit, they shall be

included in the quotation and furnished as part of the initial

supply

of

themachine.Formulti-unit nstallations, he

requirem ents for quantities f special tools a nd fixtures shall

be mutually agreed upon by the purchaser and the vendor.

These or similar tools shall be used during shop assembly

and post-test disassemblyof the equipment.

3.8.2 When s pecial tools are provided, they shall be pack-

aged in a separate, rugged metal box or boxes and shall be

marked “special ools for (TagAtem Numb er).”Each tool

shall be stampe d or tagged to ind icate its intended use.

SECTION 4--INSPECTION, TESTING, A ND PREPARATIONFOR SHIPMENT

4.1

General

4.1.1 After advance notification of the vendor by the pur-

chaser, the purcha ser’s representative shall have entry to all

vendor and subvendor plants where manufacturing, testing,

or inspection of the equipm ent is

in

progress.

4.1.2 Th e vendor shall notify subvendors of the purchas-

er’s inspection and testing requirements.

4.1.3 The vendorshallprovidesufficientadvancenotice

(see 4.3.1.3) to the purchaser before conducting any inspec-

tion or test that the purchaseras specified tobe witnessed or

observed.

O 4.1.4 The purchaser w ill specify the extent of participation

in the inspectionand estingand theamou nt of advance

notification required.

4.1.4.1 When shop inspection and testing have been

speci-

fied by the purchaser, purchaser and vendor shall meet o

coordinate manufacturinghold points and inspectors’ isits.

4.1.4.2 Witnessed mean s that a hold shall be applied o the

production schedule and that the inspection or test shall be

carried out with the purchaser or his representative in atten-

dance.Formechanical unning or performance est, his

requires written notification of

a

successful preliminary test.





24 API STANDARD 681

4.1.4.3 Observed means that the purchaser shall be noti-

fied of the iming of the nspection or test; however, the

inspection or test shall be perform ed as scheduled, and f the

purchaser

or

hisrepresen tative s not present, hevendor

shall proceed to the next step. (Th epurchaser should expect

to

be in the factory longer than fora witnessed test.)

4.1.5 Equipment orhe pecifiednspection ndests

shall be provided by the vend or.

4.1.6 The purc haser’ s representativeshall have access o

the vendor’s quality prog ram for review.

4.2 Inspection

4.2.1 GENERAL

4.2.1.1 Th e vendor shall keep the following data available

for

at least five years

or

examination

or

reproduction by the

purchaser

or

his representative upon request:

a. Necessarycertification of materials, uch as mill test

reports.

b. Test data to verify that the requireme nts of the specifica-

tion have been met.

c.Results of documented tests and nspections, ncluding

fully identified recordsof all heat treatment and radiography.

d. When specified, final assembly m aintenance and running

clearances.

4.2.1.2 Pressure-containing parts shall not be painted until

the specified inspection of the parts is completed.

4.2.1.3 In dditionohe equirements of 2.9.3.1, the

purchaser may specify the following:

a. Parts that shallbesubjected osurface and subsurface

examination.

b. The type

of

examination equired, uch

as

magnetic

particle,iquidenetrant,adiographic, and ultrasonic

examination.

4.2.2 MATERIAL INSPECTION

4.2.2.1 General

4.2.2.1.1 When adiographic,ultrasonic,magneticparti-

cle,

or

liquid penetrant inspection of welds

or

materials is

required or specified, the criteria in 4.2.2.2 to 4.2.2.5 shall

apply unless other criteria are specified by the purchaser.

Cast iron may be inspected in accordance with 4.2.2.4 and

4.2.2.5.Welds,cast teel,andwroughtmaterialmaybe

inspected in accordance with 4.2.2.2 to 4.2.2.5.

4.2.2.1.2 It shall be the vendor’s respo nsibility to review

the design limits of all componen ts in the event that more

stringent requirementsare necessary. Defe cts that exceed he

limits imposed in 4.2.2 shall be remov ed to meet thequality

standardscited, as determined by the InspectionMethod

specified.

4.2.2.2 Radiography

4.2.2.2.1 Radiography shall be in accordance with ASTM

E 94 and ASTME

142.

4.2.2.2.2 The acceptance standard used for welded fabri-

cationsshallbeSectionVIII,Division

l ,

UW-52, of the

ASMECode.Theacceptance standardused forcastings

shall be Section VIII, D ivision 1, App endix 7, of the AS ME

Code.

4.2.2.3 Ultrasonic Inspection

4.2.2.3.1 Ultrasonicnspectionhall be in accordance

with Sec tion V, Articles 5 and 23 of the ASM E Code.

4.2.2.3.2 The acceptance standard used for welded fabri-

cations shall be Section VIII, Division, Appendix 12,of the

AS MECode.Theacceptance standardused for castings

shall be Section VIII, D ivision 1, Appendix 7, of the ASM E

Code.

4.2.2.4 Magnetic Particle Inspection

4.2.2.4.1 Both w et and dry methods of magnetic particle

inspection shall be in accordance with AST M E 7 09.

4.2.2.4.2 The acceptance standard used for w elded fabri-

cations shall be Section VIII, Division

l ,

Appendix 6 and

Section V, Article 25, of the AS ME Cod e. The cceptability

of

defects in castings shall be based on a comparison with the

photographs in ASTM E 125. For each type of defect, the

degree of severity shall not exceed he imits specified in

Table

4.

4.2.2.5 Liquid Penetrant Inspection

4.2.2.5.1 Liquidpenetrant nspection hallbe in accor-

dance with SectionV, Article 6, of the ASME Code.

4.2.2.5.2 Th e acceptance standard used for welded fabri-

cations shall be Section VIII, Division l , Appendix 8 and

Section V, Article 24, of the ASM E Code. The acceptan ce

standard used for castings shall be Section VIII, Division 1,

Appendix 7,

of

the ASME Code.

4.2.3 MECHANICAL INSPECTION

4.2.3.1 During assembly of the system and b efore testing,

each component (including cast-in passagesf these compo-

nents)and all pipingandappurtenancesshallbe cleaned

chemically or by anotherappropriatemethod o emove

foreign materials, corrosion products, and mill scale.





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LIQUIDRING ACUUM UMPS NDCOMPRESSORS FOR PETROLEUM, HEMICAL,ND GAS INDUSTRY ERVICES 25

4.2.3.2 When specified,hepurchaser may inspect or

cleanliness the e quipm ent and all piping and appurtenances

furnished by or th rough the vendor b efore heads are welded

to vessels, openin gs in vessel or exchangers are closed , or

piping is finally assembled.

4.2.3.3 When specified, the hardness of parts, welds, and

heat-affectedzones hall be verified as being within the

allowable values by testing of the parts,welds,or heat-

affected zones.The method, exten t, documentation, and

witness ing of the testing shall be mutually agreed upon by

the purchaser and the vendor.

4.3

Testing

4.3.1 GENERAL

4.3.1.1 Equip men t shall be tested in accordance with 4.3.2

and 4.3.3. Other tests that may be specified by the purchaser

are described in 4.3.4 and 4.3.5.

4.3.1.2 At least six weeks eforehe first scheduled

running test, the vendor shallsubm it to the purchaser, for his

review and com men t, detailed procedures for the mechanical

runnin g test and all specified running optional tests, includ-

ing accep tance criteria for all monitored parame ters.

4.3.1.3 The vendor shall notify the purchaser not less than

fiveworking days before the date the equipment will be

ready for testing. If th e testing is reschedu led, the vendor

shall notify th e purchaser not less than five working days

before the new test date.

4.3.2 HYDROSTATIC TEST

4.3.2.1 Pressure-c ontaining artsincludinguxiliaries)

shall be tested hydrostatically with liquid at a minimum of

1.5

times the maximum allowable working pressure but not

less than 1.5 bar gau ge (20 pou nds per square inch gauge).

The test iquidshall be at a higher emperature than the

nil-ductility transition empera ture of the material being

tested.

4.3.2.2 If the part tested is to operate at

a

temperature at

which the strength of a material is below the strength of that

material at room temperature, the hydrostatic test pressure

shall be multiplied by a factorobtained by dividing the

allowable working stress for the material a t room tempera-

ture by that at operating temperature. The stress values used

shall confo rm to those given in AS ME B3 1.3or piping or in

Section VIII, Division 1, of the AS ME Cod e or vessels. The

pressure thus obtained shall hen be the minim um pressure at

which hehydrostatic test shall be performed. The data

sheets shall list actual hydrostatic test pressures.

Table 4 aximum Severity of Defects in

Castings

TYPe Defect Max imum Severity Level

Lineriscontinuities

1

II Shrinkage

2

III Inclusions

2

IV

Chillsndhaplets

1

V

Porosity 1

VI Welds 1

4.3.2.3 Where applicable,ests hall be in accordance

with the ASM E Code . In the event that a discrepancy exists

between the code test pressure and the test pressure in this

standard, the higher pressure shall govern.

4.3.2.4 The chlo ride conten t of liquids used to test auste-

nitic stainless steel materials shall not exceed 50 parts per

million. To prevent deposition of chlorides as a result

of

evaporative drying, all residual liqui d shall be removed, and

tested parts shall be dried at the conclusion of the test.

4.3.2.5 Tests shall be maintained for a sufficient period of

time to permit complete examination f parts under pressure.

The hydrostatic test shall be considered satisfactory when

neither leaks nor seepage through the ca sing or casing joint

is observed for minimum of 30 minutes. Large, heavy cast-

ings may require a longer testing period-to be agreed upon

by the purchaser nd he vendor. Seep age past nternal

closures required for testing of segmented cases and opera-

tion of a test pump to maintain pressureare acceptable.

4.3.3 MECHANICAL RUNNING TEST

4.3.3.1

The requirements of 4.3.3.1.1 through4.3.3.1.3

shall be met before the m echanical running test is performed .

4.3.3.1.1 The contract shaft sealsandbearings hall be

used in the machine for the mechanical runn ing test.

4.3.3.1.2 All joints and connections shall be checked for

tightness, and any leaks shall be corrected.

4.3.3.1.3 All warning, rotective, and control evices

used during the test shall be checked, and adjustments shall

be made

as

required.

4.3.3.2 The vendor's standard mechanical running test of

the machine shall be conducted a t normal speed for

a

mini-

mum

of

one hour, andcorrectoperation of the control

system, if furnished, shall be demonstrated.

4.3.3.3 The requirements of 4.3.3.3.1 to 4.3.3.3.3 shall be

met during the mechanical running test.

4.3.3.3.1 Duringheechanical runnin g test,he

mech anical operation of all equipm ent being tested and the

operation of the test instrumentation shall be satisfactory.

Th e meas ured unfiltered vibration shall not exc eed th e lim its

of 2.1.2.2 and shall be recorded hroughou t the operating

speed range.




A P I STDmb8l

96 0732290 0 5 5 0 b 4 3 7 4 5

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API

STANDARD 681

4.3.3.3.2 When specified while he equipment s operat-

ing at maximu m continuous speed, and at all other speeds

that may have been specified n the test agenda, sweeps shall

be made for vibration amplitudes at frequencies other than

synchronous speed. As a minimum, these sweeps shall cover

a requency ange rom0.25 o

20

times hemaximum

continuous speed but not more than 3000 hertz (180,000

cycles per minute). f the a mplitude of any discrete, nonsyn-

chronousvibrationexceeds20percent of theallowable

vibration as defined in 2.7.2.2 the purch aser and the vendor

shallmutuallyagree on requirements or any additional

testing and on the equipment’s suitability for shipment.

4.3.3.3.3

When specified, recordings shall be made of all

real-timevibrationdata.When pecified,a copy of the

recordings shall be given to the purchaser.

4.3.3.3.4 If replacementormodification of bearingsor

seals or dismantling of the case to replace or modify other

partss equiredo orrectmechanicalorperformance

deficiencies, the initial test will not be acceptable, and the

shop tests shall be run after these replacements or corrections

are made.

4.3.3.4 Whenpecif ied, any of theequirements

of

4.3.3.4.1 through 4.3.3.4.7 shallbe met during the mechani-

cal running test.

4.3.3.4.1 All purchased vibration probes, transducers, and

accelerome ters shall be

in

use during the test. If vibration

probes are not furnished by the equipment vendor or

if

the

purchased probes are not compatibleith shop readout facil-

ities, then shop probes and readouts that meet the accuracy

requirements of API Standard 670 shall e used.

4.3.3.4.2 Shop test facilities shall include instrumentation

with the capability of continuously monitoring and plotting

rotational speed, vibration amplitude,and phase angle revo-

lutionsperminute,peak-to-peakdisplaceme nt and phase

angle (x-y-y’). Presentation of vibration displacemen t and

phase marker shallbe by oscilloscope.

4.3.3.4.3 The vibration characteristics determined by the

use of the instrumentation specifiedn 4.3.3.4.1 and 4.3.3.4 .2

shall serve as the basis for acceptance or rejection of the

machine.

4.3.3.4.4 When seismic test values are specified, vibration

data (minimumand maximum values) shallbe recorded and

located (clock angle) in a radial plane ransverse o each

bearing centerline (if possible), using shop instrumentation

during the test.

4.3.3.4.5 Testing with the contract coupling is preferred.

4.3.3.4.6 The m echanical run ning test shall verify that the

operating speed range is free

f

critical speeds.

4.3.3.4.7 Themec hanica l unnin g test of a fixed speed

machine shall be conducted at normal speed for a m inimum

O

of fou r hours, and correct operation of the control system

shall be demonstrated when applicable. In the ase of

variable speed units, the test program shall be agreed upon

by the purchaser and the vendor, and it shall include a period

of operation at maximum continuous speed

4.3.4GAS LEAKTEST

4.3.4.1 Eachompletelyssembledacuumumpr

compressor casing intended for toxic, hazardous, flammable,

orhydrogen-rich ervice hall be tested s pecified in

4.3.4.2.

4.3.4.2 Unlessotherwise p ecified, hecasing with he

end seals installed) shalle pressurized to the rated disc harge

pressure,

or

in the caseof vacuum pu mp s to 1 bar g

(1

5 psig),

held at thispressure or aminimum of 30minutes,and

subjected to a soap-bubb le test or another approved test to

check for gas leaks.

4.3.5PERFORMANCE

TEST

4.3.5.1 Liquiding vacuum pumpshall be tested in

accordance with HEI

Performance Standards

fo r

Liquid

Ring

Vacuum Pumps,

or PNEURO P 6612 standards, or as

mutually agreed to between purchaser and vendor.

4.3.5.2 When specified, the comp ressor, together with it’s

ring liquid system, shall be subjec ted to a pe rformance test,

the extentof which, and the applicable test methods, shall be

agreed to between purchaser and vendor.

4.3.5.3 Unlessotherwisespecified hemachineshall be

tested on dry air and water.

4.3.5.4

The performance test may be com bined with the

mechanical running test.

4.3.5.5 For vacuum pumps, test data shall be recorded at

one speed ative suction p ressures varying from atmosphe ric

pressures to m aximum vacuum. F or compressors, test data

shall be recordedatonespeedfrom minimum discharge

pressure omaximumdischargepressure.Thepointsare

subject to negotiation between purchaser and endor.

4.3.5.6

The dry air and water performance shall be within

the tolerancesgiven

in

Table 5.

4.3.5.7 Performanc e at the rated operating point shall be

calculated from test data in accordance with the vendor’s

standard procedures, or as otherwise specified. Where the

test is to be performe d und er different conditions or w ith dif-

ferent fluids from those specified, the method of converting

the test results to the specified conditions shall alsoe agreed

upon (see Appendix H).

4.3.5.8 If it is necessary to dismantle a pump or compres-

sor for a correction, such as improvem ent

of

efficiency, the

initial test will not b e acceptable, and the final hy drotest, gas




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INDUSTRYERVICES 27

O

leak test, and perform ance test shall be repeated after he

correction is made.

4.3.5.9 Theperform ance test hallbe onducted using

only one contract rotor, unless otherwise specified.

4.3.5.10 The vendorshallmaintainacomplete,detailed

log of all final tests and

shall

prepare the requircd number f

copies, including test curves and data, certified for correct-

ness. All preliminary tests and mechanical checks shall be

comp leted by the vendor before the purchaser’s witnessed

performance test.

4.3.5.1

1

Theequiremen ts of 4.3.5.1 l .

1

through

4.3.5.11.6 hall bemetbefore heperformance est is

performed.These temsapply only to machin eswithoil

lubricated bearings.

4.3.5.1 1.1 Th e con tract shaft seals and bearings shall be

used in the machineor the performance test. At the vendor’s

request, hepurchasermayapprove heuse of substitu te

seals for reasons such as incompatibilityf the contract seals

with the test fluid. The accep table level of leakage during

testing shall be mutually agreed upon by the purchascr and

the vendor.

4.3.5.1 1.2 Allubricating-oilndiquid-sealant res-

sures, viscosities, and temperatures shall beithin the range

of operating values recommended in the vendor’s operating

instructions for the specified unit being tested. For circulat-

ing ubrication ystems,oil flow rates or achbearing

housing shall be measured.

4.3.5.1 1.3 For circulating ubrication systems, est-stand

oil filtration hall be 10micronsnominalor better. Oil

system omponents ownstream of the filters shall be

cleanedprior to the test in accordancewith the vendor’s

criteria for field installation.

4.3.5.11.4 Bearing s used in oil mist ubricationsystems

shall be prelubricated.

4.3.5.1 1.5

All joints and connections shall bc checked for

tightness, and any leaks shall be corrected.

4.3.5.1 1.6 All warning,protective,andcontroldevices

used during the test shall be checked, and adjustments shall

be made as required.

o 4.3.6 OPTIONALTESTS

The

purchaser will specify in the inquiry or in the order

whe ther any of th e shop tests specified in 4.3.6.1 to 4.3.6.5

shall be performed.

o

4.3.6.1 Complete-Unit Test

Suchcomponents as compressors,gears,drivers, ing

liquid system, and auxiliaries that make up a complete unit

may be tested together

as

a

comp lete unit.

A

separate auxil-

Table 5-Performance Tolerances

Varlable Tolerance (%)

Ratednlet volume - 0

Rated power + 4

Rlng hquld

flow

rate * 10

Note:

Standard Industry tolerances are I n accordance wlth HEI performance

standards for hquld nng vacuum pump s. The se are m ore liberal than the

tolerances shown Ln Table 6, and

I f

used could result ln the selection

of

a

smaller machme

iary test may be performed with the pu rchaser’s approval.

When specified, orsional vibration measuremen ts shall be

made

to

verify thevendor’sanalysis. By agreem ent he

complete-unit est may be com bined with he mecha nical

running test of on e or mo re of the individual componen ts

specified by the purchaser.

o 4.3.6.2GearTest

The gear shall be tested with the machine un it during the

mechanical running test.

o 4.3.6.3Sound-LevelTest

The sound-level test shallbeperformed naccordance

with purchaser requirements.

o 4.3.6.4 Ring Stabil ity Test

For variable speed machines a test agreed to between the

purchaser and the vendor shall be conducted to establish the

operating limits of liquid ring stability.

o 4.3.6.5Auxiliary-EquipmentTest

Auxiliaryequipment uch as control ystems hallbe

tested in the vendor’s shop. Details

of

the auxiliary equip-

ment tests shall be developcd jointly by the purchas er and

the vendor.

4.4 Preparat ion orSh ipment

4.4.1 Equipment shall be suitably prepared for the type of

shipment specified. Th e preparation shall make the equip-

ment capable of withstanding six months of outdoor storage

from he ime of shipment, with

no

disassembly required

before operation, except for inspectionf bearings and seals.

If storage for a longer period is contemplated, the purchaser

will consultwith hevendor egarding hc ecommended

procedures to be fo llowed.

4.4.2 The equipment shall be prepared for shipment after

all testingand nspcctionhavebeencompletedand he

equipment has been released by the purchaser. The prepara-

tion shall include that specified in 4.4.2.1 through 4.4.2.1 .

4.4.2.1 Exterior urfaces, xcept or orrosion esistant

materials and machined surfaces, shall be given at least one






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28 API STANDARD 681

coat

of

themanufacturer’s tandardnon-lead ndnon-

chromate paint.

4.4.2.2 Exteriormachinedsurfaces,except orcorrosion

resistantmaterials, hall be coated with a uitable ust

preventative.

4.4.2.3 Exposedhaftsndhaftouplingshall be

wrapped with w aterproof, moldab le waxed cloth or vapor-

phase-inhib itor aper.Theeams hall be sealedwith

oil-proof adhesive tape.

4.4.2.4 Bearingassemblies shall be fullyprotected rom

the entryof moisture and dirt.

f

vapor-phase-inhibitor crys-

tals in bags are installed in large cavities to absorb moisture,

the bags must be attached

in

an ac cessible area for ease of

removal. Where applicable, bags shall be installed in wire

cages attached to flanged covers, and bag locations shall e

indicated by corrosion-resistant tags attached with stainless

steel wire.

4.4.2.5 The interior

of

the equipment shall be clean; free

fromcale,weldingpatter, ndoreign bjects; nd

sprayed or flushed with a suitable rust preventative that can

be removed with solvent. T he rust preven tative shalle ap-

plied hroughallopeningswhile hemachine is slow-

rolled.

4.4.2.6 Flangedopening s hall be provided with metal

closures at least millimeters (YÍ6 inch) thick,with elastomer

gaskets, and at east four full-diameter bolts. For studded

opening s, all nuts needed for the intended service shall be

used to secure closures.

4.4.2.7 Threadedopenings hallbeprovidedwith teel

caps or round-h ead steel plugs. In no case shall nonmetallic

(such as plastic) caps

or

plugs be used.

Note : These are shipping plugs; permanent plugs are covered in 2.3.7.

4.4.2.8 When a spare rotor is purchased, it shall be pre-

pared for unheated indoor storage for a period of at least

three years. The rotor sh all e treated with a rust preventa-

tive and shall be ho used in a vapor-barrier envelo pe with a

slow-release volatile-corrosion inhibitor. The rotor shall be

crated for domestic or export shipment, as specified.pur-

chaser-approved resilient material 3.0 millimeters (% inch)

thick [not T etrafluoroethylene (TFE)or Polytetrafluoroeth-

ylene (PTFE)] shall be used between the rotor and the cra-

dle at the support areas. The rotor shall not be supported at

journals.

4.4.2.9 Internal steel areas f bearing housings and carbon

steel oil systems’auxiliaryequipmentsuchas eservoirs,

vessels, and piping shall be coated with a su itable oil-solu ble

rust preventive.

4.4.2.10 Liftingpointsand ifting ugs hallbeclearly

identified on theequipmentorequipmentpackage.The

recommended ifting rrangement hallbe dentified on

boxed equipment.

4.4.2.1 1

The equipment shall be identified with item and

serial num bers. Material shipped separately shall be identi-

fied with ecurelyaffixed,corrosion-resistantmetal ags

indicating the item and serial number of the equipment for

which it is intended. In addition, crated equipment shall be

shipped with duplicate packing lists, one inside and one on

the outsideof the shipping container.

4.4.3 The vendor hallprovide hepurchaser with the

instructions necessary to preserve the integrityf the storage

preparation after the equipment arrives at the job site and

before startup.

4.4.4 Auxiliaryipingonnectionsurnished on the

purchased equipment shall be impression stamped

r

perma-

nently tagged to agree with the vendor’s connection table or

generalrrangementrawing.ervicendonnection

designations shall be indicated.

4.4.5 One copy of the manufacturer’s installation instruc-

tions shall be packed and shipped with the equipm ent.

4.4.6 Open ings hat have been beveled for welding shall

be provided with closures designed to prevent entrance of

foreign materialsand damage to the evel.

SECTION 5” VENDOR’S DATA

5.1

General

5.1.1 The nform ation o be furnished by thevendor s

specified in 5.2 and 5.3. The vendor shall complete and for-

ward the Vendor Drawing and Data Requirements

orm

(see

Appendix G ) o the addresses noted on the inquiry or order.

This form shall detail the schedule for transmissionf draw-

ings, curves, and data as agreed tot the timeof the proposal

or

order, as well as the number and type of copies required

by the purchaser.

5.1.2 Thedatashall be identified on transmittal cover)

letters and in title blocks

or

title pages with the following

information:

a . Pur chase rher ’s corporate name.

b. Job/project num ber.

c. Equipment item number and service name.

d. The inquiry or purchase order number.

e. Any otherdentificationpecified in thenquiry r

purchase order.





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A P I

S TD* b &L 76

m 0732270 0550b4b

b5Y

m

LIQUID

RING

VACUUM PUMPS ANDCOMPRESSORS

FOR

PETROLEUM,CHEMICAL, ND

GAS

INDUSTRYSERVICES

29

f.

Vendor’sdentifyingroposalumber,hoprder

number, serial number, or other reference required to identi-

fy return correspondence completely.

5.1.3

When pecified, a coordinationmeeting hall be

held,preferablyat hevendor’splant,within our osix

weeksafter hepurchasecommitment.Unlessotherwise

specified, the vendor shall prepare and distributean agenda

prior o hismeetingwhich,

as

a minimum, will nclude

review of the following items:

a. Purchas e order, scope of supply, unit responsibility, and

subvendor items.

b. Data sheets.

c.App licable pecifications and previously greed upon

exceptions.

d. Schedu les for transmittal of data, prod uction, and testing.

e. Quality assurance program and procedures.

f. Inspection, expediting, and testing.

g. Schem atics and b ills of material for auxiliary systems.

h. The physical orientation of the equipment, piping, and

auxiliary systems.

i. Coupling and seal selections.

j . Bearing ife.

k.

Sizing criteria for auxiliary equipment.

5.2

Proposals

5.2.1 GENERAL

The ven dor shall forward he original and the specified

number of copies of the proposal to the addressee specified

in the inquiry documents.As a minim um, the propo sal shall

include the data specifiedn 5.2.2 through 5.2.4 and a specif-

ic statemen t that the system and all its com ponen ts are

in

strict accordance with this standard.If the system and com-

ponents are no t n strict accordance, the vend or shall include

a list that details and exp lains each deviation. The vendor

shall provide details to enable the purchaser to evaluateny

alternative designs proposed. All correspondence shall be

clearly identified n accordance with 5.1.2.

5.2.2RAWINGS

5.2.2.1

Thedrawingsdescribed on the Vendor Drawing

and DataRequirements orm seeAppendix

G )

shallbe

included.As

a

minimum, hefollowingpreliminary data

shall be furnished:

a. A general arrangement or outline drawing for each major

skid or system showing estimated o verall dim ensions, nd

b. Cross-sectional drawings showing details f the proposed

equipment.

c. Piping and instrumentation diagrams (P&IDs) nd lists of

major components and instrumentation.

5.2.2.2

If “typical” rawing s, chem atics, and bills of

material are used, they shalle marked up to how estimated

weight and dimension data and o reflect the equipment and

scope proposed.

5.2.3 TECHNICAL DATA

The following data shalle included in the proposal:

a. The purchaser’s data sheet with complete vendor’s infor-

mation entered thereon and literature to fully describe detai

of the offering.

b. Completed purchaser’s noise data sheet or the form from

the appendixof API Standard 615.

c. The Vendor Draw ing and Data Requirements form (see

Appendix

G)

indicating the schedule according to which the

vendor agrees to transmit all the data specified as

art

of the

contract.

d. A schedule for shipmentf the equipment, in weeks after

receipt of the order.

e. A listof recomm ended spare parts for start-upnd normal

maintenance purposes.

f. A list of the special tools furnished for m aintenance. The

vendor shall statef metric items ar e include dn the offering.

g. A statementof any special p rotection required for startu p,

operation, and periods of idleness under the site conditions

specified on the data sheets. The list shall show the protec-

tion to be furnishe d by the purch aser,as well as hat included

in

the vendor’s scope of supply .

h. A com plete tabulation of utility requirem ents, such as

steam, water, electricity,air, and the nam eplate power rating

and perating ower equirements of auxiliary rivers.

(App roxim ate da ta shall be defined and clearly identified as

such.)

i.

A

description of the tests and inspection procedures for

materials,

as

required by 2.9.1.4.

j. A description of specialrequirements,specified in the

purchaser’snquiry and as utlined in 2.9.1.3, .1.2.1,

3.1.2.2, .1.3.4, .1.4.2, .2.1.3, .2.4.1, .2.4.8.1, and

3.2.5.3.4.

k. A list of similar machines installed and operating under

conditions analogous to those specifiedn the proposal.

1.

Any startup, shutdown, or operating restrictions required

to protect the in tegrity f the equipm ent.

m. List of vendor’s proposed manufacturers for auxiliary

equipment and instruments.

n . A description of proposed alarm and shutdown systems,

when included

in

vendor’s scope of supply.

o.

Method of calculation used to convert from performance

condition s on dry air an d water o he specified operating

conditions.

5.2.4URVES

5.2.4.1

The vendorshallprovideperformancecurves o

encompass the mapof operations, with any limitations indi-

cated hereon. Curves shall show volumetric capacity and

required poweras

a

function

of

discharge pressure (compres-




30 API

STANDARD

681

sors)or nletpressure vacuumpumps).Curvesshallbe

based on dry air at20°C (68°F) wit h wa ter at 15OC (60OF)as

the ring liqu id. For v ariable speed applications, cu rves hall

show the full range of operation from minimum speed o

maximum continuous speed.

5.2.4.2 Estimated performance curves based on the speci-

fied conditions for the process gas and ring liquid shall be

provided.

5.3

ContractData

5.3.1 GENERAL

5.3.1.1 Thecontr act information o be furnished by the

vendor s specified n Appendix

G.

Each draw ing, bill of

material, and data sheet shall have

a

title block in the lower

right hand corner hat shows he date of certification, he

reference to all identification data specifiedn

5.1.2,

the revi-

sion number and date, and the title (see 5.3.2nd 5.3.3).

5.3.1.2 The purchaser will promptlyreview hevendor’s

data whe n he receives them; however, this review shall not

constitute permission o deviate from any requirements

in

the order unless specifically agreed uponn writing. After he

data have been reviewed, the vendor shall furnish certified

copies in the quantity specified.

5.3.1.3 A com plete ist of vendor data shall be ncluded

with the first issue of major drawings. This list shall contain

titles, drawing numbers, and a schedule for transmission of

all data the vendor will furnish (see Appendix

G).

5.3.2RAWINGS

Th e drawings furnished shall contain sufficient informa-

tion so that with the drawings and the manuals specified in

5.3.6, the purchaser can properly install, operate, and main-

tain the ordered equipment. Drawings shall e clearly legible

and shall be identified in accordance with 5.3.1 l .As a min-

imum, each drawing shall include the details forhat drawing

listed

in

Appendix G.

5.3.3 TECHNICAL DATA

Data shall be subm itted in accordance with App endix

G

and dentified in accordan ce with 5.3.1.1. If any drawing

comm ents or specification revisions necessitate

a

change to

the data sheets, the vendor shall provide revised data which

will be used by the purchaser to correct the data sheets for

reissue as part of the order specifications.

5.3.4 PROGRESS REPORTS

Th e vendor shall submit progrcss reports to the pu rchaser

at

the

interval specified on the Vendor Drawing and Data

o 5.3.5PARTS LISTS AND RECOMMENDED

SPARES

5.3.5.1 Th e vendor shall submit com plete parts lists for ll

equipment and accessories supplied. Th e lists shall include

manufacturer’s unique part numbers, materials of construc-

tion,anddelivery imes.Materials hall be identified as

specified

in

2.9.1.3. Each part shall be completely identified

and show n on cross-sectional

or

assembly-type drawings so

that the purchaser may determine the interchangeability

of

the part with other equipment. Parts that have been modified

from standard dimensions and/or finish t o satisfy specific

performance requirements shall be uniquely dentified by

part number or nterchangeabilityand utureduplication

purposes. Standard purchased items shall be identifiedy the

original manufacturer’s name and part number.

5.3.5.2 Th e vendor shall ndicate on the above parts lists

which parts are recommended spares for startup and which

parts are recommended for norm al maintenance (see 5.2.3,

Item f ) . The vendor shall forward the lists to the purchaser

promptly after receipt of the reviewed draw ings and in tim e

to permit order and delivery f the parts before ield start-up.

The transmittaletter hall be identifiedwithhe ata

specified in 5.1.2.

5.3.6 NSTALLATION,OPERATION,AND

MAINTENANCE MANUALS

o 5.3.6.1 Th e vendor hall rovide ufficientwrittenn-

structions and aist of all drawin gs to enable the purchase r to

correctly install, operate, and maintain all of the equip ment

ordered. When specified, this information shall be compiled

in a m anual with a cover sheet containingall reference-iden-

tifying data required in 5.1.2, an index sheet that contains

section titles, and

a

comp lete list of referenced and enclosed

drawings by title and drawing number. When specified, the

manualshallbeprepared or hespecified nstallation;a

typical man ual is not acceptable.

5.3.6.2 Any special information required for prop er instal-

lation design (such as special piping, foundation, and grout-

ing procedu res) that is not on the draw ings shall be provide d

separate from he operating and maintenance nstructions.

This nformation hallbe orwardedata imemutually

agreed upon in the order, but not later than the inal issue of

prints. This information shall also be included in the Instal-

lation, Operation, and Maintenance Manual.

5.3.6.3 Manuals hallbe orwarded no more than two

weeks after all of the specified tests have been successfully

completed. When specified, manuals shall include a section

that provides special instructions for operation at specified

extreme environmental conditions, such as temperatures. As

a minimum, the m anual contents described in Appendix

G

Requirementsormseeppendix

G).

shalllsoencluded.





APPENDIX A-LIQUID RING VACUUM PUMP AND

COMPRESSOR SYSTEM DATA SHEETS

31





A P I S T D * h A L

96

m 0732290 0 5 5 0 b 4 9 363

LIQUID RING VACUUM

Page 1 of

Job

No.temo.

Purch.rdero.

PUMP AND COMPRESSOR

Inquiry NO. BY

SYSTEM DATA SHEET

Revision Date

Applicable

to: O

Proposal

O

Purchase

O

Asuiltervice:

INFORMATIONTOBECOMPLETED: BYPURCHASER Y MANUFACTURER BYPURCHASER

OR

MFR.

DESIGN, MANUFACTURE, INSPECTION, AND TESTING SHALL CONFORM TO SPECIFICATION:

4 For:

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A P I

STDvb8l

'76 m 0732290

0550b50 085 m

Page

2 of

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VACUUM

PUMP AND COMPRESSOR Revision Date

SYSTEM BY

Job

No.

Item No.

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Job No. Item No.

PUMP AND COMPRESSOR

Revision Date

SYSTEM DATA SHEET

BY

1

SPEEDS i SHAFT

LIQUID RING MACHINE CONSTRUCTION FEATURES

3

4

5

6

7

8

9

10

12

13

14

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19

20

O

Mfr:

O

Model:

Testress.kPa) - Helium:ydro:

6

O Type:

API

670

Max.esign

25

VIBRATION DETECTORS E m

Max.orking

24

Oil Pressure to be Greater than Coolant PressurePort PlateKone Material:

23

Oil Heater Electric Steam

Manifold Material:

2

Oil Viscosity

I S 0

Grade:

Thickness:mm);orr.

Allow.:

(mm)

1

1

1/2 NPS Minimum

Oil

Fill & Drain 2.8.2.4)

O

Material 2.9.2.5):

27

28

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PUMP

Revision

Date

SYSTEM BY

Job No. Item No.

35






A P I S T Da b 8 L 76

W

0732270 0550b53 894 m

LIQUID RING VA CUUM

Job

No.

Item No.

PUMP AND COMPRESSOR

Revision Date

SYSTEM DATA

SHEET

BY

1

Seal

Data

I

Seal Construct ion

MECHANICAL SEAUPACKING

3

4

5

6

7

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36






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A P I STD*hAL 9 h 0732290 0 5 5 0 6 5 4 7 2 0 W

LIQUID RING VACUUM

PUMPANDCOMPRESSOR Revision

SYSTEM DATA SHEET

Job No.

Item No.

Date

BY

1

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Page 7 of

LIQUID RING VACUUM

Job No.

Item

No.

PUMP AND COMPRESSOR

Revision Date

SYSTEM DATA SHEET

BY

1

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~~ ~

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A P I

STD*68L

96 W 0732290 0550656 5 ~ 3

Page 8

of

LIQUID RING VACUUM

PUMP

Revisionate

SYSTEM

BY

Job

No. Item No.

I I INSTRUMENTATIONICon’tl

42

Heaters:

kW

oordination Meetina Reauired (5.1.3)5

kWAuxiliaries):W

Yr. Retention of Final Assembly Clearances (4.2.1.1 e)

4

Instrumentir:

il

/hr

nits of Measure (Dwqs., Nameplates, etc.) 2.10.3):

43

kWDriver):W

46

49

48

Remarks:

7

I PurgeAirritrogen): m

B

/hr





LIQUIDINGACUUM

Job No.

PUMPANDCOMPRESSOR

Revision

SYSTEM DATA SHEET

Page 9

of

Item No.

Date

BY

RING LIQUID

COOLER

kW Cooler Item Number:

41

40

47

46

ASME code.

5

1)

Units exempt from code stamp hell have longitudinal weld seams spotexamined per Para. UW-52

of

4

Rl3. KS: 1)Outside tube area excluding area in tube sheets.

3

Channel Nozzle Flanges:hell Flanges: 42

Channel Flanges:hell:11 Shell:

I

Channel Flanaes:

I

I

42

43

Shell Flanges:

Rl3. KS: 1)Outside tube area excluding area in tube sheets.

W -

~

I ChannelNozzleFlanges:

44

1)

Units exempt from code stamp hell have longitudinal weld seams spotexamined per Para. UW-52

of

45

46

ASME code.

47

40

49

50

51

40





~~ ~~ ~

A P I S T D t b 8 l 76

0 7 3 2 2 7 0

0550b58

3 7 6

P a g e a o f

LIQUID RING VAC UUM Job. No. Item No.

PUMP A ND COMPRESSOR

Revision

Date

SYSTEM DA TA SHEET

BY

2

3

4

5

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Type:

43

Mfr.:

I

44

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49

50

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52

53

Lube:

Inletress.:

Other:

Customer/User:

Location:

ICustomer P.O.No.:

lltems

N o f s k

Eauio.

Nefs).:

This data sheet is provided courtesy of

Rev.:

Engineers, ASME B73.2M-1991

Issuedy:ate:

he American Society of Mechanical

Factoryrder

No(s).:

Pumperial No(s).:

41YRIGHT 2002; American Petroleum Institute Document provided by IHS Licensee=Sincor Venezuela/5934214100, User=,08/14/2002 13:03:08 MDT Questions or comments about this message: please callthe Document Policy Management Group at 1-800-451-1584.



LIQUID RING VA CUU M

PUM P A ND COMPRESSOR

SYSTEM DATA SHEET

Pase II of

Job. No. Item No.

Revision Date

BY

38 ManufacturerASIC DATA:

40

ameplate:Werviceactor

C.T. Description:

Voltageip

%

7

Self-Balance Primary-Current Method

Loaded Unloaded

6

PROTECTION:

Fulloltage Reducedoltage %

5

MOTOR ARRANGED FOR DIFFERENTIAL

TARTING:

4

In Separate Conduit Boxes

Temp.ise:C)boveC)Y:

3

In Same Conduit Box

Insulation:lassype

2

WINDING TEMP. DETECTOR& SPACE HEATER LEADS:

Synchronous RPM

1

( C)orAlarm C)orShutdown

39

Max. Stator Winding Temperatures:

Voltshaseertz

48

Extendedeads engthm)

49

50

42




A P I

STD * b8L

9 b

m

0 7 3 2 2 9 0 0550bb0 T 2 4

m

LIQUID RING VA CU UM

PUMP AN D COMPRESSOR

SYSTEM DATA

SHEET

P a g e L o f

Job. No.

Item No.

Revisionate

BY

43




A P I S T D * b A 1 96 m 0732290 0550663 960 m

Job No.

LIQU ID RINGACUUM Purch.rder No,

PUMPANDCOMPRESSOR Inquiry

NO.

SYSTEM DA TAHEET

Revision

Page

1 of

I tem No.

Date

BY

Date

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~~

A P I STD*bAL 9b

m

0732290 0550662 AT7

m

Page 2 of

LIQUID RING VACUUM

Job No.

Item No.

PUMP AND COMPRESSOR

Revision

Date

SYSTEM DATA SHEET

BY

1

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OPERATING CONDITIONS

NORMAL

A

TART

UP

ATED

OTHER CONDITIONS

(All Data On

Per

Unitasis)

B

r

Gas

I I

I

l I I

I

~~

SCFM (14.7 psia &

60

' dry)

Mass

Flow (Lb/min)

(wet/dry)

~ ~

INLET CONDITIONS

I I

45




API

S T D x b 8 1 9 6 W

0 7 3 2 2 9 0 0550663 7 3 3

LIQUIDINGACUUM Job

No.


SYSTEM DATA SHEET

Page 3 of

Item

No.

Date

BY

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~~

A P I

STDrb8L96 0732290 0550664 b7T

Page

4

of

LIQU ID RINGACUUM

Job

No. Item No.

PUMP AND C OMPRESSOR

Revision Date

SYSTEM DATA SHEET

BY

1

2

ating Ring

lan ed

osition

Rating

acing

Size

O.

onnection

3

$%nZor

sk t

StucPdedhreaded r

4

Machine Discharge

Machine Inlet

System Discharge

System Inlet

.3.8.4)

2.3)

Ring Liquid Inlet

1

Cooling Water

O

Machine Drain




~~ ~

A P I S T D x b d L 76 m 0732270 0550665

506

m

LIQUID RING VACUUM

Job No.

PUMPANDCOMPRESSOR

Revision

SYSTEM DATA SHEET

Page 5 of

Item No.

Date

BY




A P I

S T D + h d L

76 m 0732270

0 5 5 0 b b b

442

Page

6

of

Item No.

IQUID RING VACUUM

Job No.

PUMP AND COMPRESSOR

Revision Date

SYSTEM DATA

SHEET

BY

1 SEPARATOR

3.1.2)

I

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48

49

50

51

52

49






A P I

STDxb8L 9 6 W 0732270

0550667 389

LIQUIDINGACUUM

Job

No.

PUMP AND COMPRESSOR Revision

SYSTEM

DATA

SHEET

Page

of

Item No.

Date

BY

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

ALARM

& SHUTDOWN SWITCHES

(3.2.5.1)

(TABLE 2)

40

Pre-Alarm Shutdown I Pre-Alarmhutdown

47

48

49

50

50





API STD*b81

96

0732290 0550668 2 1 5 m

Page 8 of

Item No.

LIQUID RING VACUUM

Job No.

PUMP AND COMPRESSOR

Revision Date

SYSTEMDATASHEET

BY

1 INSTRUMENTATION Con’t)

2

Switch Closures:

3

AlarmContactsShall: pen lose

to

Sound Alarm and

be

Normally: nergized e-Energized

4 Shutdownontactshall: pen lose to Tripnde Normally: nergized e-Energized

5 Note:Normal Condition s whenCompressor is inOperation

G

47emarks:

48

49

50

51

52

51






LIQUIDINGACUUM Job No.


SYSTEM DATA SHEET

Page 9 of

Item No.

Date

BY

11

RING LIQUID COOLER 1

~

2

4

Supplier:

No.

Unitsequired:

Duty: Bt u h

Model Number:

~ ~~~~~

Coder Item Number:

5

OPERATING ONDITIONS

6 I Shell Side I Tube Side

30

NOZZLE SIZES

1

Weights (lbs) - Eachundle:undle

&

Shell: Full ofater:

I Shell Side

I

Tube Side

2

33

34

35

36

37

38

39

40

41

42

Shell:

I

Channellanges:

46

ASME code.

5

1)Units exempt from code stamp shell have longitudinal weld seamsspot examined per Para. UW-52 of

4

REMARKS: 1) Outside tube area excluding area in tube sheets.

3

Shell Flanges: Channelozzlelanges:

47

I

~

48

49

5

-

51

52

52




LIQUID RING VACUUM


SYSTEM DA TA SHEET

P a g e a o f

Job.

No. Item

No.

Revisionate

BY

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

Rev.:

Engineers,ASME

B73.2M-1991 53

IssuedBy: Date:

he American Society

f

Mechanical

2

Factoryrder No@).: Pumperial No@).:

his data sheet is provided courtesyf

1

Items

No@).:

Equip.

No(+

0

Customer

P.O.

No.:

9

Location:

8

CustomedUser:

7

Other:

53




A P I S T D e b 8 L 96 0732290 0550b7L

B O T

m

LIQU ID RING VACUUM

PUM P A ND COMPRESSOR

SYSTEM DA TA SHEET

P a g e x o f

Job No. Item

No.

Revision Date

BY

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

ullol tage educed Voltage % PROTECTION:

46

oaded Unloaded

O Self-Balance Primary-Current Method

47

oltageip %

C.T. Description:

48

Extendedeads Length

(Ft.)

49

50

54




A P I

S T D * b d L

96 m

0732290 0550672 7Yb

m

LIQUID RING V A C U U M


SYSTEM DATA SHEET

P a g e z o f

Job.

No.

Item No.

R e v i s i o n Date

BY

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

37

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

AccelimeMtr. & Load & 85% Rated Volt ): Sec

3

AccelerationlmeMtrnly & Rated Volt.) Sec.

50

49

Total Shaft End Float:

8

Lubeil &

(psig)

7

Bearing:6

No. of

Starts per Hour:

5

Rotor/Fleld Wk2& Mtr. Shaft (Lb -Ft

’)

4

41

42

AccelimeMtr. & Load & 85% Rated Volt ): Sec

3

AccelerationlmeMtrnly & Rated Volt.) Sec.

50

49

Total Shaft End Float:

8

Lubeil &

(psig)

7

Bearing:6

No. of

Starts per Hour:

5

Rotor/Fleld Wk2& Mtr. Shaft (Lb -Ft

’)

4

55






A P I S T D * b 8 L

96 m 0732290 0550673 682 m

APPENDIX B-LIQUID RING VACUUM PUMP SCHEMA TIC

57






A P I S T D vb 8L 96

m 0732290 0550674 519 m

58 API

STANDARD

681

at discharge

port

connections

Radial Flow-Conical Design

The L iqu id Ring Pumping Act ion Ro t o r Imbalance

The rotor propels

a

band

of

ring llquid that rotates inside the cylindrical As can be seen In the above dlagrams and the previous paragraphs, the

body The rotor axis is offset from the body

a l s .

As ccntnfu gal force forms

liquid nng rotates

at

the same speed as the rotor but

IS

offset from the

a l s

the nng of liquid inside the body, it almost fills, then almost empties, each

of the rotor.

rotor cham ber during a single evo lution. This sets up the plston action.

If,

for example, the

rotor

has twenty chambers, twenty liquld pistons

Vacuum inlet ports and atmospheric discharge ports provide flow paths

at

complete an outward inlet and

an

Inward discharge stroke for each revolu-

the inner edges of he rotor chambers for the gas mixture being handled. tion of the rotor. The frequency of this imbalanced piston would be twenty

times the rotational

or

equal to the

vane

passlng frequency.

Because

of

the large mass and higher frequency

of the

llquld piston, the

rotor imbalance becomes

a

mmor factor, and the liquid piston imbalance

becomes

a

major factor in the vibration ch aractenstic s of the entire system.

Figure 8-1-Liquid Ring Vacuum Pump Schematic





~

A P I S T D * b 8 2

96

m 07322900550675455 m

APPENDIX C-SHAFT DEFL ECTION SCHEMA TIC

59






A P I STD*b8L

96

0732290

0 5 5 0 6 7 b

391

H

60 API STANDARD681

Notes: 2. Due to the operational characteristlcs

of

the liquid ring pump, a pressure

dif ferenti al e x m between the inlet and discharge of the pump. Th is pressure

1. As ln any machine, the static weight

“ W ’

of the liquid rlng pump shaft difference “ ’will deflect the shaft exten sion. This chang e in deflection at

and

rotor

will deflect the shaft downw ard. This results in an upw ard deflec- the extension

“X”

may be as much as 0.005 inch and will vary directly with

tion of the shaft extension. differential pressure.

Figure C-1 ”Sh aft Deflection Schematic




~ ~~ ~

A P I

S T D * b 8 1 76

m 0 7 3 2 2 7 0

0550677

228

m

APPENDIX D-LIQUID RING VACUUM PUMP RING L IQU ID

FLOW SCHEMATICS

61YRIGHT 2002; American Petroleum Institute Document provided by IHS Licensee=Sincor Venezuela/5934214100, User=,08/14/2002 13:03:08 MDT Questions or comments about this message: please callthe Document Policy Management Group at 1-800-451-1584.



API

STD*bBL

96 0732290

0 5 5 0 b 7 8 164

m

62

API

STANDARD 81

Rlng

llquld

121

Figure A-LRVP Oncehroughystemigure B-LRVP Partialecirculation

System

4 - Y

14

$

P

"

I

5 7

Y

See

Note

6

Figure C-LRVP Total Recirculation System

Figure D-1-Liquid Ring Vacuum Pump Ring Liquid Flow Schematics






Figures A & B 1. Optionalnletressureontrolalve.

l . Inlet isolating valve.

2. Inlet check valve.

3. Inlet pressure gauge.

4. Gauge isolation valve.

5. Gashing liquid separator.

6. Discharge check valve (see Note

2).

7. Pressure relief valve (see Note 2).

8. Ring liquid drain trap (see Note 3).

9. Inlet isolating valve.

10. Y Strainer.

11. Pilot operated automatic valve (see Note 4).

12. Flow regulating valve

01

orifice.

13. Ring liquid pressure gauge.

14. Gauge isolating valve.

15. Liquid ring pump and drive.

16. Inlet pressure control (see Note

1).

17. Partial ring liquid recirculation valve (Figure B only).

Figure C Additions

18. Levelgauge.

19.

Make-up valve.

20. Optional ring liquid recirculation pump.

2 l . Temperature gauge.

22. Heat exchanger.

23 Temperature gauge.

24. Drain valve.

2. Optional pressurized discharge check valve and pressure

relief valve. (Required n liquid ring compressors or vacuum

pumps with positive discharge toa contained system.)

3. Optional pressurized discharge ring liquid drain system.

(Required for compressors.)

4. Pilot operated isolating valve. Direct acting solenoiday

be substituted at purchaser’s discretion for small sizes.

5. Recirculation pump optionalased on purchaser’s

requirements or application details.

6. Optional level controlsmay be specified by purchaser.





~

API STD*b8L 96 m

0732290

0550680 812

m

APPENDIX E-MECHANICAL SEAL AND PIPING

ARRANGEMENT SCHEMATICS

65






A P I

S T D x b 8 3 9 b 0732290

0550683

759

66 API

STANDARD 81

Note2 Note 2

Seal chamber

(auxiliary sealing device)

Throat bushin

Shaft

SINGLE SEAL

Note 2

Note

2

(for forced

UNPRESSURIZED DUAL SEAL

Note 2 Note 2 Noie

2

* * >

PRESSURIZED DUAL SEAL

Legend: F-Flush-Quench

V-Vent

D-Dram B-Barrier

Figure E-1-Typical Mechanical Seal Arrangem ents




LIQUID RING VACUUM PUMPS

AND

COMPRESSORS FOR PETROLEUM, CHEMICAL, AND GAS INDUSTRY SERVICES 67

CLEAN PUMPAGE

ZT rr.7r

J

r .J

.

I 'L

Plugged connections

for possible future

.

circulatingluid

Plan 1

Integral (Internal) recirculation from

pump discharge to seal

Plan 2

Dead-ended seal chamber i th no

circulation of flushed fluid; water cooled

stuffing-box jacket and throat bushing

required when specified

Plan 11

Plan 12

Plan 13

Recirculation from pump case

Recirculation from pump case

RecirculatiÒn from sealchamber

through orifice to seal

through strainer and orifice to seal

through orificeand back to

pump suction

Plan 21

Plan 22

Plan 23

Recirculation from pump case through


Recirculation from seal with pumping

orifice and heat exchanger to seal

strainer, orifice, and heat exchanger

ring through heat exchanger and

to sealackoeal

DIRTY

OR SPECIAL PUMPAGE

Plan 31


cyclone separator delivering clean fluid

to seal and f luid with sol ids back

to pump suction

Plan 32

Injection to seal from external source

of clean fluid (see Note 3)

8

LEGEND

PS Pressure switch with block valve

Cyclone separator

@

Pressure gauge with block valve

ialhermometer

I

@ Flowndicator

I

Plan 41


cyclone separator delivering clean fluid

through heat exchanger

o

seal and

fluid with solids backo pump suction

++-

Y-typestrainer

-$& Flow-regulating alve

Block valve

Check valve

II- Orifice

Figure E-2 Piping for Single-Seal Arrangements and Primary Seals

f

Tandem-Seal Arrangements




API

STD*b8L 76 m 0732270 0550683

5 2 1 m

68 API STANDARD 681

Vent connection

Level gauge

* -

Reservoir

- Connection

Q

I O

I

+k -- Connection D

Plug

Plan

51

Dead-ended blanket (usual ly methanol,ee Note 3);

typical ly used with auxi l iary seal ing device

(single- or double-seal arrangement in Figure -1)

,

xternal pressure

.- i

ource

,

Plan 53

Presssurized external fluid reservoir (see Note)

with forced circulation; typically used ith

tandem-seal arrangement in Figure E-1

4

-

Plan 61

Tapped connections for purchaser's use; Note 3

applies when purchaser s to supply fluid (steam,

gas, water, etc.) to auxiliary sealing device

(single- or double-seal arrangement in Figure E-1)

- 1 . . Normallypen

When specified

- Fill plug

Level gauge

Reservoir

.When specified

(may be f in type)

Connection

B

'

* Drain valve

Plan 52

Nonpresssurized external fluid reservoir (see Note 3)

with forced circulation; typically used with

tandem-seal arrangement in Figure E-1

Plan

54

Circulation of clean fluid from external system

(see Note

3);

typically used with double-seal

arrangement in Figure E- i

From external

source

------.

L -

Plan 62

External fluid quench (steam, gas, water,tc.;

see Note

3);

typically used with throttle

bushing or auxiliary sealing device

(single- or double-seal arrangement in Figure E-1)

Notes:

1 These plans represent commonly used systems. Other variations and systems are available and should

be specified In detail by the purchaser or mutually agreed upon by the purchaser and the vendor.

2. See Figure

E-2

for explanation of symbols not specrfied here.

3 .

When supplemental seal flu d

is

provided, the purchaser will specify the fluid characteristics. Th e

vendor shall specify the volume, pressure, and tem perature required, where these a re factors.

Figure E-3-Piping forThrottle Bushing, Auxiliary Seal Device, Tandem Seals, or

ouble Seals




A P I STD*h8L

96

W

0732290

0550bdY

q h 8 m

APPENDIX F-MATERIAL LIST

69





Table F-1-Material

List

Major Part Location Material Specification

Cast parts-

castng s and internals Grey iron

Duc tde Iron

Austenitic ductile iron

Carbon steel

Statnless steel

N ~ ck l e& nlckle alloys

Fabricated parts-

casing s and internals Steel

Stainless steel

Nlckle & nlckle alloys

Shafts

Shafi sleeves

Steel

Mar tens~ t~ctainless steel

Austen~tlc stainless steel

Duplex stainless steel

Nickle

&

nickle

alloys

Martensitic stainless teel

Austenitic stainless teel

Nickle & nickle alloys

ASTM A48

AS 1830

DIN 1691

SIS

O1 15

BS 1452

ASTM A536

ASTM A395

DIN 1693

SIS

1407

BS 2789

ASTM A439

BS 3468

ASTM A2 16

ASTM A351, A743or A744

DIN 17445

SIS 2343 or 2353

BS 1504

Hastelloy B

Hastelloy C

ASTM A494

ASTM A36, A53, A203or A516

DIN 17100

BS 3100

ASTM A240 or A276

DIN 17440

BS 970

Hastelloy B

Hastelloy C

ASTM B333

ASTM B575

ASTM A29

or

AS76

DIN 17440

ASTM A276

DIN 17440

ASTM A276

DIN 17440

ASTM A572

DIN 17440

Hastelloy B

ASTM B335

Hastelloy C

ASTM B574

ASTM A276

DIN 17440

ASTM A276

DIN 17440

Hastelloy B

Hastelloy C

ASTM B335

ASTM B574

Grade

Class 20 min.

Grade T150 min.

G G l O

min.

MNC 7 05 min.

Grade 150 min.

60-45-12 min.

60-40-1

8

min.

WCA min.

CF3, CF3M, CF8, FBM, CA6NM , or CN7M

1.4581, 1.44406, 1.4410

Hastelloy B

Hastelloy C-4

CW-2M, CQ-7M

or

N12

A l

304,304L, 316,316Lor 316TL

Hastelloy B-2

Hastelloy C-276

NlOOOl min.

N 10276

I045

420 or 43

I ,402

1

303 , 304 , 316

or

329

1.4401

65

1

.O080

Hastelloy B

Hastelloy C-276

NlOOOl min.

N

10276

420

1.402

304 or 316

1.4401

Hastelloy B

Hastelloy C-276

NlOOOl min .

N 10276

Note: Temperature limitation

40'F

to 250'F






APPENDIX G-LIQUID RING VACUUM PUMPS AND

COMPRESSORS VENDOR DRAW ING AND ATA

REQUIREMENTS

71





LIQUID RING VACUUM PUMPS

AND COMPRESSORS

VENDOR DRAWING AND DATA REQUIREMENTS

JOB

NO. ITEM NO.

P URCHA S ERDER NO. DATE

REQU ISITION NO.ATE

INQUIRY

NO.

DATE

PAGE 1 O F 2 BY

FOR

REVIS ION

SITE UNIT

SERVICE

Proposalaidderhallurnishopies of data

for

alltemsndicated by an X.

I r

eviewb

Vendor shallurnishopiesndransparencies of drawingsndatandicated.

Finalb

T

Vendor shallurnishopiesndransparenciesfrawingsndatandicated.

Vendorhallurnishperatingndaintenanceanuals.

Final-Received from vendor

Due from vendor'

Review-Due from vendor'

I l I I I

I

LIQUIDRING PUMP OR COMPRESSOR

1. Certifiedimenslonalutlinerawingndst ofonnections.

~

aProposal drawings and data do not have to be certifiedr as-built.

bPurchaser will indicate n this column he time frame or submission of materials using the nomenclature given at the endf the form.

CBidder shall complete these

wo

columns to reflect his actual distribution schedule and include this form with his proposal.

72






A P I

S T D * b 8 L

96 m 0732290 0550688 003 m

JOB NO.

ITEM NO.

LIQUID RING VACUUMUMPS

PAGE 2

OF 2 BY

AND COMPRESSORS

DATE REV.

NO.

VENDOR DRAWING AND DATA REQUIREMENTS

Propo sal Bidder shallurnishopies of data forll itemsndicated

by

an X.

Reviewb Vendor shallurnishopiesndransparencies of drawingsndatandicated.

t

I

Finalh

Vendor shallurnishopiesndransparencies of drawingsndatandicated.

Vendor shallurnishperat ingndaintenanceanuals.

I I

Final-Received from vendor

Due from vendor'

Review-Due from vendor'

MOTOR

28. Certifled dlmenslonal outhne drawlng.

29. Cross-sectional drawing andblll of mater&.

30. As-bullt data sheets.

31. Performance data.

32. Certlfied drawmas f auxillary systems.

33. nstallatlon, operatlon, and mamtenance manuals

I

34.Spareparts ecommendations.

GEAR

I

I

I

I

I

I

I 35. Certifled dlmenslonal outline drawmgs and 1st of connectlons

I

I

I

I

36. Cross-sectlonal drawlng and blll of mate rlais.

I

37As-bulltdatasheets.

I I I 38.echanicalunnlnaest

loa.

I I I 39earanufacturer'standardest logs I I I I I I

40 Optlonal test data and reports.

41

Installation, operation, and maintenance manuals.

42. %are Darts recommendatlons.

aProposal drawmgs and data do not have to be certlfled or as-built.

bPurchaser w ~ l lndlcate In thls column theme frame for subrnlsslon

of

rnaterlals usmg the nomenclature given at the end of the form.

'Bidder

shall complete these two columns to reflect his actual dlstributlon schedule and include

hls form

wlth hls proposal.

Notes:

l . Send all drawings and data to

2.

All

drawings and data must show project, appropriation, purchase order, and item numbers in additiono the plant

location and unit. In additiono the copies specified above, one set f the drawings/instructions necessary for field

installation must be forwarded with the shipment.

3.

See expanded description of specif ied in items below.

Nomenclature:

S-number of weeks prior to shipment.

F-number of weeks after firm order.

D-number of weeks after receiptof approved drawings.

Date

Signature

(Signature acknowledges receiptof all instructions)

73




~~

A P I

S T D * b A L

9 6 m

0732290 0 5 5 0 b A 9

T 4 T m

APPENDIX H-SYSTEM CONSIDERATIONS, OPERATING VARIABLES, AND

TEST PERFORMANCE CONVERSION

H. l SystemConsideration-Factors

Affect ing Performance and Select ion

of

Liquid Ring Vacuum Pump and

Compressor Systems

Liquid ring vacuum ump and co mpressor performance in

the user's process

s

significantly influenced by process vari-

ables. Process variables which must be considered during

process development, design, and specification may include:

H. l .l VARIABLES

FOR

GAS INLETTO PUMPING

(OR

COMPRESSING) EQUIPMENT

H. l . l . l Temp erature, pressure, mass flows, and molecular

weights.

H.1.1.2 Saturationconditionsandheats of vaporization

and condensation.

H.1.1.3 Solu bility of gas es in the ring liquid fluid.

H.1.1.4 Presence of liquid or solid carryover, and particle

size if applicable.

H.1.1.5

Variationswith ime in processgasspecification

(that is, batch processes).

H.1.1.6 Pump-up or pump-down ime imitations.

H.1.1.7 Reactivity

of

the gas, or effects

of

the gas on the

ring liquid.

H.1.2 VARIABLES FOR GAS DISCHARGEDTO

PROCESS

OR

VENT SYSTEM

H.1.2.1 Maximum allowable) emperatures.

H.1.2.2 Pressures, ncludingmaximumallowable.

H.1.2.3 Gas mass flows required or desired downstream .

H.1.2.4 Permitted (or allowable) liquid carryover from the

system.

H.1.2.5 Permitted (or allowable) vapor carryover from the

system.

H.1.3 VARIABLES FOR RING LIQUID SYSTEM

H.1.3.1 Temperatures ndpressures t he nlet o he

system.

H.1.3.2 Temp eratures and pressures required (or desired)

at the discharge from the system.

H.1.3.3 Vapor pressureunderequilibriumconditions at

the pum p or com presso r suction and discharge within the

operating range.

H.1.3.4 Specific gravity in the operating range.

H.1.3.5

Viscosity n he operating range.

H.1.3.6 Reactivity with the gas stream , if applicable.

H.1.3.7 Miscibility/solubilitywith nlet iquids or on-

densed vapors.

H.1.3.8 Fouling otential.

H.1.3.9 Specific heat and thermal conductivity within the

operating ranges.

H.2 OperatingVariables-Checklist

H.2.1

Inlet mixture may be cooled in pump increasing net

capacity.

H.2.2 Inletmixturemayormaynotbe aturatedwith

condensable vapors.

H.2.3 Inletcondensablesmaybe miscibleor mm iscible

wtih other or with service liquid.

H.2.4 Inletcondensables may be partiallycondensed n

pump increasing net capacity.

H.2.5 Cooler service iquid emperature may ncrease net

capacity and lower effective vapor pressuref service liquid.

H.2.6

Lower service iquid effective vapor pressure may

increase net capacity.

H.2.7 Condensing aporsmayncreaseerviceiquid

temperature iseand ncreaseheat oad ooptionalheat

exchanger.

H.2.8

Service iquidspecificheat ower hanwatermay

increase temperature rise.

H.2.9 Service liquid specific gravity lower than water may

affect performanc e.

H.2.10 Service iquid specific viscosity ower han water

may decreaseBHP nd, in turn, educe erviceiquid

temperature rise.

H.2.11 Solubility of inlet gas in s ervice liquid may red uce

net capacity.

H.2.12 Inletvaporsmaycondenseandcontaminate he

serviceiquidodifyingtsharacteristics.Miscible

condensables may accum ulate in service liquid and become

a dominant factor in determining net effective vapor pres-

sure. Immiscible condensables with ower specific gravity

than service liquid may collect at gadliquid interface and

75




A P I STD*b8b 9 b 0732290 0550670 761

76 API STANDARD 681

become dominant factors in determining net effective vapor

pressure.

H.2.13 Net performance is generally determined by vapor

pressureateffectiveservice iquid emperature.For wo

stage pumps, the latter is the interstage temperature.

H.2.14 Higher service liquid rate may reduce temperature

rise and increase net capacity at rated conditions.

H.2.15 Serviceiquidype may determineffective

service liquid temperature and performance.

Once-throughgenerallyprovides owest e rvice iquid

temperature with higher effective service liquid temperature.

Fullecirculationermitsse of separateoolant

medium-generallywithigherffectiveerviceiquid

temperature.

A

minimal service liquid purge flow should be

used to control service liquid contamination.

H.2.16 Bac k ressu res ther than standard will affect

performance.

H.3

Conversion

of

Standard Test

Performance to Specif iedOperat ing

Condit ions

H.3.1 Since operating onditionswithespectonlet

gases,condensablevapors,service iquid,andother field

conditions are often different from hose

of

the Standard

Test, a conversio n must be carried out. Conversio ns of this

kind shall be based upon the manufacturer’s standard m ethod

andhall egreed pon efore-hand by the arties

involved.

H.3.2 A check list of operating variables will provide the

user with a better understanding f conversions to be made.

H.3.3 It shouldbenoted hat igorousmathematical

solution or conversion is generally not practicle.The equip-

ment selection procedure is usually a reiteration of a series

of approximations. The latter are ased upon a combination

of user and manufacturer ield experience, vendor laboratory

tests, and similarity.


api-581, liquid ring vacuum pumps and compressors for petroleum, services

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