Download - maintenance pump
-
7/25/2019 maintenance pump
1/87
PUMPS
-
7/25/2019 maintenance pump
2/87
Defnition
-
A device whichadds energy to auid, causing anincrease in its
pressure andperhaps amovement o the
uid
Pump
-
7/25/2019 maintenance pump
3/87
rinciple Functions of pump
produce velocity overcome the fricti
on and fitting losses (shock losses)
overcome external
pressure
-
7/25/2019 maintenance pump
4/87
umping System
-Consists of a pump
-The suction branch
d aws flu id f om a sou ce
-The discharge branch
t anspo ts flu id to the dest inat i
on
-
7/25/2019 maintenance pump
5/87
Types of umps
isplacement pumps
! "eciprocating pumps
! "otary pumps "otordynamic pumps
! Centrifugal pump
! Propeller pump #et pumps
Axial Flow pump
-
7/25/2019 maintenance pump
6/87
isplacement umps
The liquid or gas is displacedfrom the suctionside to the discharge side of the pump by themechanical variation of the volumeof a chamber
or chambers.
They can be further subdivided into two classes :
1. eciprocating Piston or Plunger Pumps!. otary Pumps
-
7/25/2019 maintenance pump
7/87
isplacement umps
-
7/25/2019 maintenance pump
8/87
"eciprocating umps
Pumping done by plungeror pistonina li$uid cylinder
Suitable and better efficiency for handling small volumesand high differentialpressure
Suitable for any re$uired viscosity Self priming (self evacuating air from p
ump and suction line)
% & ' rea n
-
7/25/2019 maintenance pump
9/87
iston ump
The liquid or gas is displacedin and thenfrom the cylinder by the moving of piston
in a cylinder "mechanical variationof the volume#
$pplicationsMost suitable and e%cient for handlingsmall volumes and high di&erential pressure
Suitable to handle any required viscosity
-
7/25/2019 maintenance pump
10/87
iston ump
-
7/25/2019 maintenance pump
11/87
-
7/25/2019 maintenance pump
12/87
"eciprocating umps
oes not discharge a steady flow* instead in a series of pulsations
Therefore cause vibration and hammering at high speeds resulting in shockto pump and fittings
+sually fitted with air vessel to reduceeffects of unsteady flow of discharge
-
7/25/2019 maintenance pump
13/87
"otary umps
Pumping done by forcinga li$uid through the pum
p cylinder or casing by means of screws or gear Suitable forintermediate
range of volume* interme
diate differential pressureandlow or intermediate viscosity
Self priming
'ess efficient
-
7/25/2019 maintenance pump
14/87
"otary umps
Steady flow but less efficient than reciprocating pumps because of large are
as and running clearance ,ear increases the clearances nd results in loss in efficiency* espec
ially when handling low viscosity fluids
-
7/25/2019 maintenance pump
15/87
Screw ump
-
7/25/2019 maintenance pump
16/87
Screw ump
Screw pumps are rotary positive displacement pumps.
'low of liquid is a(ial
)iquid is carried between the screw threads ofrotors and displaced as the screws rotate.
Screw pumps themselves do not create pressure*they simply transfer a quantity of +uid from the inlet to
the outlet.
Pressure is built up on the outlet as a result of resistance+ow in the discharge line.
-
7/25/2019 maintenance pump
17/87
-ertical Screw ump
-
7/25/2019 maintenance pump
18/87
.ear ump
-
7/25/2019 maintenance pump
19/87
.ear ump
,ften called e(ternal gear pumps
Suitable for handling all clean liquids
particularly e&ective where the +uid has lubricatingproperties. They are often used as attached lubricating oil pumps inau(iliary engines and as transfer pumps in lubricatingand fuel oil systems.
Should not be run dry or else they will overheat andsei-e up
y/pass valve arrangement is required
-
7/25/2019 maintenance pump
20/87
.ear ump
-
7/25/2019 maintenance pump
21/87
-ertical .ear ump
-
7/25/2019 maintenance pump
22/87
-ane ump
-
7/25/2019 maintenance pump
23/87
-ane ump
Sliding vane pumps are light Simple in construction 0ompact
)ow/cost
They are particularly suitable for low and mediumpressure duties
0an handle both gases and liquids
,ften used as attached circulating water pumps ofau(iliary engines
0an also be used for air handling as rotary compressorsor e(hausters
-
7/25/2019 maintenance pump
24/87
'obe ump
-
7/25/2019 maintenance pump
25/87
'obe ump
,ften called internal gear pumps
More gentle than e(ternal gear pump
The generation of high localised pressures is avoided
Shear forces generated are substantially lower
Suitable for handling higher viscosity and shear/sensitive
+uids
$lthough it is equally suitable for handling low viscosityand even volatile liquids with suitable shaft seals
The normal range of pressure rising to !1 g2cm!
andcapacities up to 344 tonnes2hr
-
7/25/2019 maintenance pump
26/87
'obe ump
5ave two types nown as the Three/'our and Seven/6ight
The Three/'our are particularly suitable for handlinghigh/viscosity +uids such as heavy fuel oil and can runcomparatively slow speeds
The Seven/6ight types are designed to operate at higherspeeds of around 7!4 rev2min and are e%cient in handlin
lower viscosity +uids.
-
7/25/2019 maintenance pump
27/87
'obe ump
8oring procedures
-
7/25/2019 maintenance pump
28/87
'obe ump
Two types
Three/'ourSeven/6ight
-
7/25/2019 maintenance pump
29/87
ump Curve
-
7/25/2019 maintenance pump
30/87
ischarge Calculation
$ single acting reciprocating pump has a bore of 944 mmdiameterand piston stroe of !44 mm. f the cranshaft speed of the pump i94 rpm; it delivers nd the theoreticaldischarge; coe%cient of discharge and percentage of slip.
Solution:?iameter @ 944 mm Stroe @ !44 mm n @ 94 rpmAactual @
-
7/25/2019 maintenance pump
31/87
"otordynamic ump
Ability to handle large volume ow rates at regular delivery Ability to handle low to medium heads
Ability to handle liquids rom medium to lowviscosities
Ability to handle contaminated liquids Quiet in operations
ow care and maintenance requirements !omparatively lower cost" #o ability to sustain pressure when at rest" $he inductive action relies entirely on the impeller
motion
-
7/25/2019 maintenance pump
32/87
"otordynamic ump
-
7/25/2019 maintenance pump
33/87
Centrifugal ump
-
7/25/2019 maintenance pump
34/87
Centrifugal ump
-
7/25/2019 maintenance pump
35/87
Centrifugal ump
-
7/25/2019 maintenance pump
36/87
Principle functions of0entrifugal Pump
%ery simple design&oving part is only an
impeller attached to a shat
driven by a motor$wo main parts' impellerand di(user
A di(user or volutehouses the impeller and
captures the water o( theimpeller
-
7/25/2019 maintenance pump
37/87
Centrifugal ump
-
7/25/2019 maintenance pump
38/87
,orking rinciple of Centrifugal ump
)$he impeller with fxed blades *vanes+ is mounted ona rotating shat in a fxed casing"
)hen the impeller rotates, a high velocityis impartedto the liquid due to the centriugal orce"
)As the liquid ows radially outwards into the volute)shapedpump casing or a di(user, its high velocity is converted intostatic pressure")$he vacuumcreated at the pump inletenables theatmospheric pressure to orce more liquid into the inlet
opening")$his process will continueas long as rotating motion isprovided to the rotor and the supply o liquidis available"
-
7/25/2019 maintenance pump
39/87
/ow pressure is produced
in centrifugal pumpsFrom the -ernoullis equation, the total head o a liquid particle inmotion is the sum o its potential head, .inetic head and pressureheady"
v2 p
H /
Z 0 )))))) 0 ))))) 2g 1g
2n a centriugal pump, the sectionarea o a volute casing and
di(user is gradually increased"
!onsidering two sections 3 and 4"$he area o section3 is smaller,the area o section4 is bigger"
-
7/25/2019 maintenance pump
40/87
/ow pressure is produced
in centrifugal pumps$he -erloullis equation at section 3 and 4 is'
%34 53 %4
4 54630 )))))) 0 )))))) / 640 )))))) 0 ))))
4g 1g 4g 1g
63is equal to 64" From the continuity equation, a3%3/ a4%4
*a is the area o the section, % is the velocity at the section+"hen a4increases, then %4decreases" hen %4decreases
then 54increases"
$hereore the pressure is produced in centriugal pumps byconverting .inetic head to pressure head"
-
7/25/2019 maintenance pump
41/87
9? view of a centrifugalpump
-
7/25/2019 maintenance pump
42/87
-ertically 0ounted umps
$dvantages
6liminate the overhanging load on
wear rings ,ccupy lesser space )ess ha-ardous . less open +oors . easier mobility for engine room crew 6lectric motors are higher; less prone to
+ooding damage Simple support pump foundation )ower cost
-
7/25/2019 maintenance pump
43/87
-ertical Centrifugal ump
-
7/25/2019 maintenance pump
44/87
-ertical Centrifugal ump
ear 7ing
-
7/25/2019 maintenance pump
45/87
0ulti!stage ump
iming to get higher pressure
-
7/25/2019 maintenance pump
46/87
ropeller ump
)arge Eolume rate and low pressure provided
8xample 9se' &ain sea water cooling in steam condenser o turbine engin
-
7/25/2019 maintenance pump
47/87
Centrifugal Pump Components
Centrifugal Pump can be split into two main assemblies.
Mechanical Assembly Hydraulic Assembly
-
7/25/2019 maintenance pump
48/87
0entrifugal Pump $ssembly
&echanical Assembly
:hat seal:hat
-earings;ousing
Drive couple
;ydraulic Assembly
2mpeller:uction 2nlet
%olute
:eal 7ing
-
7/25/2019 maintenance pump
49/87
5ydraulic $ssembly 'unctions
mpeller
2t is a rotating component whichtransers energy rom the motor that
drives the pump to the uid being
pumped by orcing the uid outwardsrom the centre o rotation" 2mpellersare round discs with fns to push the
uid"
Suction nlet2t is the inlet where the water to be
pumped enters
Eolute 2t is the outlet where the water exit
Seal ing2t prevents the medium rom lea.ing
to the atmosphere
0omponents in a0entrifugal Pump
-
7/25/2019 maintenance pump
50/87
Centrifugal ump arts
Eolute0asing
mpeller Suction 0over
-
7/25/2019 maintenance pump
51/87
0omponents in a0entrifugal Pump
Mechanical $ssembly 'unctions
Shaft seal2t is to prevent the medium *liquid+ rom
lea.ing into the atmosphere"
Shaft2t is connected to the impeller to provide
the centriugal orce"
earings2t is used to provide the shat a rictionless
movement"
5ousing 2t holds the di(erent parts together in thepump"
?rive couple2t connects the motor shat and the
impeller shat" $he motor provides theimpeller with .inetic orce
Materials
-
7/25/2019 maintenance pump
52/87
MaterialsUsed
Component Materials used Materials properties
Pump Casing Cast iron It is low impact resistance, low ductility, good forcasting, easily machinable, good strength, hard.
Impeller Bronze It is less brittle than iron and has a lower casting temperature,low-friction properties, resistance to corrosion by sea water
Shaft Stainless steels It hasa higher resistance to oidation !rust" and corrosion in
many natural and man made en#ironments.
Bearing Carbon steels Fatigue resistance and ductile core provides toughness.
-
7/25/2019 maintenance pump
53/87
1alance xial Force
-
7/25/2019 maintenance pump
54/87
1alance xial Force
-
7/25/2019 maintenance pump
55/87
1alance xial Force
Mae a balance hole to balance a(ial force
'unction of wear ring: to prevent internal leaage
-
7/25/2019 maintenance pump
56/87
erformance Curves (/!%)
0entrifugal pumps are generally operated at constant speed andregardless of load
The characteristic curves of the head2volume delivery rate for a
given design speed can be drawn.
The theoretical H/Qcurve is a straight lineof negative slope.
The real operating characteristics lies below this line to the e(tentof losses within the pump. These losses are :
a# shoc and eddy losses due to the +ow into and out of the impellb# losses due to +uid friction and turbulence.
The losses should be minimum at the design operating point.
-
7/25/2019 maintenance pump
57/87
erformance Curves (/!%)
-
7/25/2019 maintenance pump
58/87
;)Q !urve
5rovided by
&anuacturer
-
7/25/2019 maintenance pump
59/87
2fficiency of ump
6%ciency is the ratio of +uid output power to input power
'luid power6%ciency @ /////////////////
nput power
'luid power can be calculated as the product of g A 5.
The e%ciency curve is conve(
The ma(imum e%ciency occurs at a point somewhat betweenma(imum and minimum discharge head and throughputconditions.
-
7/25/2019 maintenance pump
60/87
erformance Curves (/!%)
-
7/25/2019 maintenance pump
61/87
erformance Calculation
t is used to transfer water from one tan to another; in whichthe water level is D.4 m higher; through 144 m of 1=4 mm diametepipe with friction factor f @ 4.4!4and >ttings with total value of14.4.
?etermine the pump discharge and the power input.
?ischarge
"l2s#
4
-
7/25/2019 maintenance pump
62/87
erformance Calculation
Solution:Step 1:To draw the 5/A curve according the data given and the
e%ciency curve according to the data given.Step !: To calculate system head at each discharge point by using
5system@ 5s F 5mF 5f8here: 5system // System 5ead "Unit: m#
5s // Static 5ead "m#; here is Dm
5m // Minor )osses "m#
5f // 'riction )osses "m#
E!
5m@ G H //// here G H@14
!g ) E!
5f@ f // /// here [email protected]!4; )@144m
? !g
-
7/25/2019 maintenance pump
63/87
erformance Calculation
$rea of the pipea@"9.1323# d! @ " 9.1323#( [email protected]
-
7/25/2019 maintenance pump
64/87
erformance Calculation
ased on the system head at di&erent A point; draw a system cur
-
7/25/2019 maintenance pump
65/87
erformance Calculation
n the drawing; the intersection point between 5/A curve andystem curve is the ,P6$TIJ P,ITof the pump.
t the operating point; we can get:he discharge of the pump; A @ !1.= l2s
utput pressure head; 5 @ B.< m%ciency @
he power of the pump can be calculated by:
ower @ Kg A 5
@ 14!= g2m9( B.D1 m2s ( !1.= ( 14/9m92s ( B.