Instruments, Valves, and Controls

Thank You for Attending Today’s Webinar:

Glass Level Gages 101

Your HostMike DeLacluysePresidentLesman Instrument Comiked@lesman.com

Featured SpeakerRob BolinProduct Manager Jerguson (Clark-Reliance)rbolin@clark-reliance.com

Follow the Conversation LIVE@Lesman_Inst #LesmanWebinar

Level Gage & Valve Maintenance Training

Why Use a Gage Glass?When systems fail…….”seeing is believing”

Even the most advanced fly-by-wire aircraft in the world have windows, would you fly blind?

Why Use a Gage Glass?• Level Verification

• Start-Up• Operations Confirmation• Upset Condition• Plant Emergency

• Instrument Calibration• “Safety Valve” of Level

Measurement

Gage Types• Reflex Glass

– Molded Prisms on One Side

– 1 piece of Glass per gage section

– Clean Service– Higher Pressure

Ratings– Economical Advantage– Silver / Black

Indication

Reflex Gage Components

Gage Types• Transparent Glass

– Glass is Flat, Ground & Polished on both sides

– 2 pieces of Glass per gage section

– May add shields– Allows User to See

Fluid Characteristics– Used for Interface

Applications

Transparent Gage Components

Glass Materials• Borosilicate

– Up to 600°F (315°C)– Up to 300 WSP– Over 300 WSP, Mica

Protected Transparent• HP Borosilicate

– Up to 600°F (315°C)– Higher Tolerances

• Aluminosilicate– Up to 800°F (426°C)

Glass Sizes – Industry Std (34mm)• Size 1 thru 9

Size Length Typical Visible Range1 4‐1/2'' (115mm) 3‐3/4'' (95mm)2 5‐1/2'' (140mm) 4‐3/4'' (121mm)3 6‐1/2'' (165mm) 5‐3/4'' (146mm)4 7‐1/2'' (190mm) 6‐3/4'' (171mm)5 8‐5/8'' (220mm) 7‐7/8'' (200mm)6 9‐7/8'' (250mm) 9‐1/8'' (232mm)7 11'' (280mm) 10‐1/4'' (260mm)8 12‐5/8'' (320mm) 11‐7/8'' (302mm)9 13‐3/8'' (340mm) 12‐5/8'' (321mm)

Gasket MaterialsSeal vs. Cushion Gasket– Seal Gasket is wetted &

must be compatible with the process conditions

– Cushion Gasket prevents metal-to-glass contact

– Cushion is IFG-5500 Material as Standard

• Many Customers Upgrade to Grafoil to Match Seal Gasket

– This eliminates the potential for errors during repairs

Gage Lengths• Two methods to vary gage

length:• Change glass size• Add more sections

• Multiple Sections ALWAYS on one chamber

• Do not use pipe nipples to join multiple single section gages –this will result in failure!

(1) Section Gage

(3) Section Gage

Jerguson Safety Ball Check Valves

• Also known as:– Automatic Shutoff Valve– Excess Flow Valve

• All 90-degree valves• Must be installed horizontal• Uses kinetic energy of fluid to

activate ball check• Engage at ~5 psi-differential

pressure

Importance of Ball Check Valves• In the unlikely event of gasket

failure or glass breakage the pressure differential will cause the ball check to seat preventing gas/fluid from further leakage

• Minimizes the potential for physical injury, or loss of product

• Provides a means to isolate the gage from service

If properly maintained, a glass gage will provide reliable service.

CommissioningSafety Ball Check Valves

Ball Check Valve Operation• Partially open valves

prevent the ball check from seating

• Rapid opening of isolation valves can cause glass breakage • Valves should be

periodically inspected for build up which can prevent the ball check from seating properly

Gage Inspection• Gages should be routinely

inspected for signs of wear:• Cloudy glass• Cracks or fractures • Pitted chambers / gasket surface• Excessive deterioration or rust

• Bolts torque is vital in ensuring proper operation of the gage • Gage should be isolated and

torques inspected periodically• Gaskets can relax over a period of

time and cause loss of torque

Gage Glass & Mica Shields• Mica shields protect

transparent gages in steam service

• Glass can become steam etched which can lead to potential catastrophic failures

• High quality mica enables you to see the fluid more clearly

• Proper blowdown procedure is critical in determining life of a mica shield

• Excessive condensate formation results in reduced life of mica shield

Steam etching

High Quality Mica

Low Quality Mica

Step 1Isolate gage from service, relieve internal

pressure and drain.

Disassembly

Step 2Loosen end bolts first, then work towards the center,

alternating from top to bottom and following the

sequence for tightening in reverse.

Step 3Removal and disposal of

componentsNever re-use gaskets or glass!

Step 4Clean Chamber

Step 5 Thorough Inspection

Step 6Thoroughly inspect chamber gasket surface seating area. Remove any pitting damage, steam cuts, gouges, or scars on a milling

machine. The minimum dimension shown in Figure A must be maintained.

Recessed Gasket Surface

No Recess Recessed

• Provides positive location of the seal gasket during both assembly and field repair

• Makes it possible to repair a Jerguson gage while it is mounted to a vessel

• Safety feature in the fact that it contains the gasket and helps prevent lateral movement which could lead to a gasket blow-out

Reflex Gage Assembly

• Place seal gasket on recessed surface of chamber, and cushion gasket on cover

• Lay glass prism side up on top of the cover cushion gasket

• Place chamber on top of reflex glass.

• Insert U-Bolts around chamber into the holes along the back of the cover, and carefully roll chamber over.

! Ensure gasket stays aligned throughout the process !

• Finger tighten the nuts onto the U-Bolts. Ensure bearing face of nut is against the cover

• Working from the middle set of nuts alternate outward with torque wrench in 5-ft-lb increments.

Transparent Gage Assembly • Lay back cover face up on

the table and insert T-Bolts into holes

• Flip the back cover over like shown

• Place seal gasket on recessed surface of chamber, cushion gasket on recessed surfaces of covers

• Place transparent glass on the cover

• Place the chamber on top of the glass

• Place the second set of glass on top of the chamber

• Place front cover on top of T-Bolts

! Ensure gasket stays aligned throughout the process !

• Finger tighten the nuts onto the T-Bolts. Ensure bearing face of nut is against the cover

• Working from the middle set of nuts alternate outward with torque wrench in 5-ft-lb increments. You will need to hold a wrench on the hex head for to prevent the nut from spinning.

Glass Gage Maintenance

LumaStar EPL-100 LED Illuminator

Features:• Cover up to 4 Sz. 9 Sections

with One Illuminator• LED’s have 10 year nominal

life rating• Easy clamp-on Installation• Maintenance Free – No bulb

changes• No Heat Generation• Fits Variety of Gages

Safe+View• Personnel Protection

from glass failure• Impact Resistant• High Temperature or

Caustic Service• Fits Jerguson and other

gage glasses• Field Installable

• No disassembly required!

Questions?

Instruments, Valves, and Controls

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