pumps description functionalities and availability

description of pump

1. Pumps And Piping

190 FLuD MECHANICS

FIGURE ‘85
Pump flow system.

2. *PUMPS

3. A Centrifugal Pump

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4. SS

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D.
fn | :

4

5. Centrifugal

Plunger

Diaphragm

6. P.D Pumps

Piston pump
» Apply direct pressure to liquid by reciprocating piston
+ Contain stationary piston or plunger to displace liquid

oPiston pump
oPlunger pump
oDiaphragm pump

Centrifugal Pumps

Rotary pumps
* The chamber movies from inlet to discharge and back to the inlet

oGear pumps
oLobe pump
oVan pump

7. Positive Displacement Pump

Piston Pump
* Discharge pressure up to 50 atm...

+ It's application is areas where high pressure is required... itis not
necessary that every P.D pump be of 50 atm...

Discharge

Connecting rod

Piston
Crosshead

Discharge
valve

Crankshaft

Suction vale

Suction

8. Positive Displacement Pump

Plunger Pump
* Used to produce 1500 atm or more...
» Usually motor driven and single acting...

9. Positive Displacement Pump

Plunger Pump

» Used to produce 100 atm. These are employed for corrosive liquid

handling... Used for corrosive/toxic liquids... 2 >

MECHANICALLY DRIVEN PUMPS USE 1/3 rd.
THE ENERGY OF AIR DRIVEN "A.0.D.e.Ds"

10. » Efficiency For P.D » Volume efficiency
Pumps The ratio of the volume

For small pumps: 40 to 50 %...

+ For large pumps: 70 to 90%...

« Efficiency independent of speed
under normal conditions. ; =

+ Decrease slightly with a increase volumetric efficiency...
suction pressure.

Effect Of Leakages On Volumetric Efficiency

Volumetric efficiency is nearly constant with pressure but slightly decrease due
to leakages.

What Are Metering Pumps

Plunger and diaphragm pumps are “metering pumps” and can provide a
constant volumetric rate (adjustable) to the process system.

11. Rotary Pumps

The chamber movies from inlet to discharge and back to the inlet...

Gear Pump

+ Minimize leakage due to close tolerance between moving and stationary
parts...

* Liquid must be clean, moderately viscous fluids i.e. light lubricating oil...

13. Rotary Pumps
Peristaltic

* Use for small flow rates and constant flow rates...
+ No air leakage or possibility to air (leak proof)...

« Application

+ Production of biomedical, pharmaceuticals etc...

14. E

Downstream
"Pipe Flange
Driveshaft Flange
Rotating Direction -
Indicator *--.,

Pump Casing-+..

++ Impeller

"+. Upstream
Pipe Flange

15. impellers

Open Impeller Semi Open Closed

16. Closed Impellers

17. A Centrifugal Pump

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18. Rotary Pumps
Centrifugal

+ Increase of mechanical energy, pressure by centrifugal force...
+ Most commonly used in the industry...
* The impellers are curved backward...

1/4 th D

Scale agate -
of the dh

cenrtrifugal pump.

19. Rotary Pumps
Multi Stage Centrifugal Pumps

+ High energy centrifugal can generate a head of 200 m only.

+ To increase the head (>200 m), multistage centrifugal pumps is used where
multiple impeller is installed on a single shaft.

20. Rotary Pumps
Leak Proof Centrifugal Pumps

(Two types use which doesn’t contain any seals or stuffing boxes)

1) Canned-rotor pumps
canned like stainless steel structure cover the rotor which keep the pumped

fluid away from the rotor.

2) Magnetic-derive pump
mpeller carries magnetic is driven by the magnetic disk on the other side of

casing walls...

INNER MAGNETS ——,

| — MAGNETIC FIELD
OUTER MAGNETS. —,

| ROTATES IMPELLER
\

FLUIDO Bat.
FROM IMPELLER

finan an

7

IMPELLER
8 2
f notanon—! /
fo
CASING moron —/"

21. Pump Priming

@ NN — *

What is it?

To remove the entrapped air inside the pump is called pump
priming

When we do it?

. First start up after a long time
. First start up after maintenance
. First start up for a new pump

How we do it?

If there is any air entrapped in the suction line, we need to
replace this air with liquid.

Air can be displaced by liquid from any tank into the suction
line and submerge the pump impeller...

22. Pump Priming
Priming of a pump is very essential step in start up of a
centrifugal pump.

Fact is that centrifugal pump are not capable of pumping air
or vapors.

Priming is the process in which the impeller of a centrifugal
pump will get fully sub merged in liquid without ce air trap
inside. This is especially required when there is a first start
up. But it is advisable to start the pump only after primping.

Liquid and slurry pumps can lose prime and this will require
the pump to be primed by adding liquid to the pump and inlet
pipes to get the pump started. Loss of "prime" is usually due
to ingestion of air into the pump. The clearances and
displacement ratios in pumps used for liquids and other more
viscous fluids cannot displace the air due to its lower density.

23. Pump Safety

A note about centrifugal pump is that it doesn't require a safety valve
while a P.D pump must have a safety valve because at certain pressure
C.F pump will stop producing any further pressure while the P.D pump will
continue to increase pressure with every stroke until or unless the safety
valve blows or the discharge is opened...

Turbulence

Turbulence may be generated in other ways than by flowing fluid in a pipe...
in general however it results from either of these scenarios, one is the
flowing fluid gets In contact with a solid boundary called as the wall

turbulence or two fluid layers moving with varying velocities contact called
as the free turbulence... Free turbulence is especially important in mixing...

24. Characteristic Curves

* The performance of a given pump is commonly illustrated by plots of actual
head, power consumption, and efficiency versus volumetric flow rate. These
plots are called characteristic curves.

+ AHis head capacity

« Pis power of the pump

+ [is the pump efficiency

Ideal (100%)

Total power, Py

AH

q
la)

FIGURE 8,12
Characteristic curves of a centrifugal pump: (a) head capacity; (b) power; (c) efficiency.

25. pinbyy 0 y 'H ‘poy ¡ploL

Flow rate, q, gal/min

Characteristic curves of a centrifugal pump operating at various
ds. (Bv permission from Perry's Chemical Eneineers' Handbool

FIGURE 8.10

Spee

26. * Pump Head

.

From an industrial point of view pump head is very important, for every
elbow/bend in pipe you have to add in a certain no. of head usually in feet
in order to accommodate the losses... i.e. 1elbow=2feet then you'd have
to add in 2 feet for every time that elbow appears in the piping...

Hu +?
En...
Pump ja
So, you can see RR omite causing us 2 feet loss in head every
time they appear so we have to add that in order to compensate the
losses... We also have 3 ft. loss in head due to the vertical piping, we
don't count in horizontal piping...

So, Total Head = 9ft. + 12ft. + some excess feet to be safe...

nu

27. + Cavitations And NPSH

+ Ifthe suction pressure is only slightly greater than the vapor
pressure some liquid may flash to vapor inside the pump a
process called as cavitations which greatly reduces the pump
capacity and causes severe erosion. If the suction pressure
is actually less than the vapor pressure there will be
vaporization in the suction line and no liquid can be drawn
into the pump.

+ To avoid the cavitations the pressure at pump inlet must
exceed the vapor pressure by a certain value called as the
net positive suction head. The required value of NPSH is
about 2 to 3 m (5 to 10 ft) for small centrifugal pumps but It
increases to 15m (50 ft) are recommended for larger pumps.

28. * How To Choose A Pump

» Usually we choose a pump on the basis of it's head which is basically a
generic term for all the force that a pump can muster up whether it in the
form of fluid velocity, pressure or something alike... let us draw a

diagram...
Mass Flow Rate 600kg/min
1

“eo

29. =

So, for very basic calculations we only need to know the flow rate
(gal/min or m*3/ min) and the friction caused by the pipe from a
table, add them up and you're good to go... basically equation
would be...

This equation has two main things that need to be calculated...
Height from point 1 to point 2, in our case it is 22ft...
You also need to account for the head you're going to be losing because
of the friction and you need to accommodate that, you can calculate the
lost head due to friction by the use of tables, here you need to know the
nominal diameter of your pipe and flow rate in gal/min...... Now all you
have to do is add them up...

|

Also you ought to add a factor of 15-20 % for a commercial design to the
values of the table...
So that makes this 23.8898 7ft...

31. -PIPING

32. Tubing

Heavy walled, relatively large diameter in Thin walled and often comes in coils several
diameter and comes in moderate lengths of hundred feet long...

20-40 ft...

Rough Walls Smoother Walls

Joined by screwed, flanged or welded fittings... | Compression, flare or solder fittings...

Made by welding, welding or piercing a billet | Made by extrusion or cold drawing...
In a piecing mill...

33. Schedule Number

(Schedule number refers to the wall thickness of the pipe)

1.5in.
Schedule
40

So, this pipe with large dia. Will have greater
thickness at same schedule no. and will sustain
pressure equivalent to small one...

34. » Measurement
» Pipes and tubing are specified in terms of their diameter and their wall
thickness... Iron pipe size (IPS) or Normal pipe size (NPS)...

+ The designation “2 inch nickel IPS pipe” means nickel pipe having the
same outside diameter as standard 2 inch pipe...

Piping Tubing

Nominal diameters Sizing indicated by outside diameter...
1/8 till 30 inches The normal value is the actual outer

>12 inches nominal diameter = actual diameter | diameter, to within very close tolerances...

Wall thickness Wall thickness
Schedule numbers | Wall thickness is given by the BWG
10,20,30,40,60,80,120,140,160 are in use... (Birmingham Wire Gauge) number ranging

But for <8 inches 40,80,120,160 are common... | from 24 (very light) to 7(very heavy)...

35. us.
im salle
0109 2468
0083 1938
0.065 1.663
209 0.1380 1476 06777 3385 0303
a 12 Gm 0532 0220 01393 1447 O2 3456 0748
14 0083 0584 0174 0.1529 LISS DEME 4174 039
16 0065 0620 0140 01623 1061 09425 4713 0476
18 000 0652 0.08 01707 0962 1041 5205 0367
3 12 0109 0657 0.262 G.1720 098 1055 3275 0891
14 0083 0709 0207 01856 O13 1230 6150 070%
lé 0065 0745 0.165 01950 0735 130 6800 0561
18 0049 0777 0.127 02034 0.678 LA477 738.5 0432
1 10 0134 0732 036 01916 0763 LMO 6550 1237
12 018 0782 0305 02047 0667 149 7500 1037
14 0083 0834 02183 ass 170 8505 0813
16 0065 0870 019 02278 0338 1354 9210 0649
Cron Velocity.
Circumference, pact;
Pt rung ent un > pd =
Outside Micknen jade ares Inside pr A
diameter, metal, sectional) ———————___ US. us. ‘Water, Weight,
in im in? area, ft? Outside Inside gal/min gal/min Ib/h Ibihd
“ 10 QIX 0982 0470 000526 03272 02571 0424 2361 AIST 1598
12 010 1032 039 000581 03272 02702 038% 2.608
14 0083 1.084 0304 0.0061 03272 02838 0348 287
16 006% 1.120 0242 000684 0.3272 0292 0326 3070
4 10 O1M 1232 0575 00088 03927 03223 020 3716
12 0109 1.282 0476 000896 03927 0.3356 0249 4021
14 0083 1334 0370 000971 03927 03492 0229 4.358
2 10 014 1732 055 00 0.5236 0454 0136 7.360
12 0109 1782 06473 00173 0326 04665 0129 7.764

+ Condensed, by permission, from J. H. Perry (6d), Chemical Engineers” Handbook, Sth ed. p. 11-12. Copyright © 1973,
McGraw-Hill Book Company, New York.
1 For steel; for copper, multiply by 1.14; for brass, multiply by 1.06.

36. sectional
Nominal Outside Watt liée aren of Imide Surface nn ser Fire
pipe diameter, Schedule thickness, diameter, metal, sectional Mast US Water, weight
size, ln im mo im in im area, It Outside Inside gal/min Ibrh Ihr
á 0.405 40 0068 026 0071 000040 0106 00708 0179 02
30 0095 azıs 0093 000025 O106 00363 0113 ası
4 040 0 008 0364 0125 000072 al 0095 0323
so 0119 0.302 0.137 00050 ml 0079 02%
i os7s 40 009 0.493 0.167 00133 0177 0129 0596
30 0126 0423 0217 00008 GI77 OIL 040
+ 040 a0 ae 0.623 0350 00011 0220 nis 0943
so 9.147 0.546 0320 000163 0720 GI 0730
4 1050 40 0113 05 0333 900371 0275 0316 1663
0 0154 0.47 0433 00000 0273 019% 1345 6725
a 135 40 013 1.049 0494 OO 0344 0275 2690 1,345
so oi 0.957 on DO 0jé4 0230 2240 1,120
“4 1.660 40 0.140 1.380 0668 OD 0435 a 457 224
so aus 278 OSS 000891 0435 MS 399 1995
4 1900 40 0.145 1610 GE DIE 0497 0421 6H 3170
so 0.200 1.200 1069 001225 0497 03 549 2343
Esta Circumference, ft Capacity at 1 Nun
si Loir al or surface, f/f velocity Pipe
Nominal Outside Watt luside mrem Inside eh Gg ee
diameter, Schedule mess, diameter, metal, sectiomal us. ter, weight
ee me a int area, f Outside Inside gal/min t/t tite
154 2.087 1075 00230 0622 DSi 104$ Ss 365
: me | ous 1.939 1477 07050 as Ds 920 4600 Sum
2 2875 40 0203 2469 1.704 003322 0.753 0647 1492 1 m
so 0276 2323 324 oo 0733 m 1920 6600 766
3 2300 40 0216 3.068 225 900 ass am zum Ham 73
= 0.300 2900 3016 004387 0916 070 2055 102
4000 40 0.226 3,548 1047 0929 3080 15400 911
E so 0318 3364 1047 0881 2720 13830 1251
4 4500 +0 0.237 4.026 LT 164 me 19800 10m
so 0337 3326 LITR 1002 358 E tase
s ms Ss ss = oe Se
30 0375 4813 E E
6 6625 40 0250 6088 1734 1SEE 000 1897
30 0.432 S761 1734 1508 NL a”
2258 2089 1557 zus
= 2625 40 0322 7981 me dr u
#0 0.500 76253 2258 14 103 u
ee m iS 2 =
zo x 2
12 1235 a0 0408. 11.935 zu 11 M ns
so 0638 11,374 2338 208 ic

37. Selection Of Pipe Sizes

The optimum size of pipe depends upon the...

Relative cost of investment

Power

Maintenance

Stocking pipe

Fittings

Low velocities should be favored especially in gravity
flow from overhead tanks...

Let's talk Reynolds number here (Newtonian Fluids) according to
Reynolds transition of laminar flow to the turbulent flow depends upon
diameter of the tube, average linear velocity of the fluid,
density and it's viscosity.

Usually laminar flow is <2100 while from 2100-4000 is the transition
region, >4000 is turbulent region.

38. TABLE 8.1
Fluid velocities in pipe

Fluid Type of flow
Thin liquid Gravity flow
Pump inlet

Pump discharge
Process line
Viscous liquid Pump inlet
Pump discharge
Steam
Air or gas

Velocity range

ft/s

0.5-1
1-3
4-10
4-8
0.2-0.5
0.5-2
30-50

30-100

m/s

0.15-0.30
0.3-0.9
1.2-3
1.2-2.4
0.06-0.15
0.15-0.6
9-15
9-30