Give descriptive Idea about the pump for engineering students

3.  Pump is a mechanical device which conveys liquid from
one place to another.
 It can be also define as a machine that transfer the
mechanical energy of a motor or engine into potential
kinetic and thermal energy pump belongs to the category
of power absorbing machines.

4.  A pump is also defined as a device, which raises or transfer
liquids at the expense of power input.
 Application area of pump the municipal water works,
power plants, agriculture, transport and many other utility
services and industries.

5.  The pump can be classified according to principle by
which the energy is added to the fluid and their design
feature as shown below:
 (A) positive displacement pumps
 (B) roto-dynamic pump
 (C) other pumps

6.  These pump operate on the principle of a definite quantity
of liquid is discharged or displaced due to the positive or
real displacement of working elements.
1) Reciprocating pump
[i] piston pumps [ii] plunger pump [iii] bucket
pump(hand-pump)
2) Rotary pump
[i] gear pump [ii] vane pump [iii] screw pump

7. These pumps operate on the principle of the rise in
pressure energy of liquid by dynamic action of liquid. The
dynamic action of liquid is carried out by revolving wheel
which has curved vanes on it. This wheel is known as
impeller.
(1) Centrifugal pump
(2) Propeller pump
(3) Mixed flow pump

8.  This pump does not belong to the category of roto-dynamic
pump or positive displacement pump.
(1) jet pump
(2) air lift pump etc.

9. 1)Head:- In the pumps, different forms of energy are
expressed in terms of height which is called “head”.
2)Suction Head:- It is the vertical height of centre line of
pump shaft above the surface of liquid or it is energy
required to lift liquid from sump to pump.
3)Delivery Head:- It is the vertical height measured from
the centre line of pump shaft to where the liquid is
delivered, or energy required to lift the liquid from pump
to end of delivery pipe.
4)Static Head:- It is sum of suction and delivery head.
Hst=hs+hd

10. 5)Velocity Head:- It is kinetic energy carried away by the
liquid at the end of delivery pipe.
hv=V²/2g, where V=velocity of liquid in pipe
6)Manometric Head:-It is the total head required to be
developed by the pump.
Hm=hs+hd+hfs+hfd+hfp+hv
7)Water Power:- It is the power required by pump to handle
the liquid to develop manometric head.
Pw=ρgQHm
8)Shaft power:-Power input to shaft of the pump by motor.
9)Efficieny of pump:-Ratio of water power to shaft power.
ηp=Pw/Ps x 100 %

11. Reciprocating pump is a positive displacement pump. In this
pump , the liquid is discharged due to the simple to and fro
motion or reciprocating motion of the piston working in the
cylinder of the pump. Hence it is called as a reciprocating
pump.

12. (1) According to type of reciprocating member of pump:-
i)Piston pump:-In this pump piston is a
reciprocating member.
ii)Plunger pump:- In this pump plunger is a
reciprocating member.
iii)Bucket pump:-When non return valve is fitted
on the piston, the piston is called the Bucket and
the pump is called bucket pump.

13. (2) According to action of liquid upon the piston ends:-
i)Single acting pump:-In this pump liquid acts on one
side of the piston only. Suction as well as delivery
takes place at alternate stroke on the same side of the
cylinder.
ii)Double acting pump:- In this pump liquid acts on
both the side of the piston. Suction and delivery strokes
occur simultaneously on the opposite side of piston.

14. (3) According to method of drive:-
i) Direct acting pump :- this pump is driven by steam
engine.
ii) Power pump:-This pump is driven by electric motor or
I.C. engine or steam turbine through a rotating crank.

15. The different components and their function in a reciprocating
pump as follows:
 Suction pipe: Connects source of liquid to the cylinder.
 Suction valve: Opens during suction stroke and closes at the
beginning of delivery stroke.
 Cylinder: Accommodates liquid during suction stroke and
discharge during delivery stroke of piston.
 Piston or Plunger: This is a reciprocal part which creates
negative and positive pressure due to its ‘to’ and ‘fro’ motion.

16.  Delivery valve: Closes during suction stroke and opens at
the beginning of delivery stroke.
 Crank and connecting rod: Converts the rotary motion of
the prime movers into the reciprocating motion of the
piston.
 Delivery pipe: Connects pump cylinder to the storage
tank.
 Prime movers: To drive the pump.

18. This pump consist of piston or piston or plunger, cylinder,
suction pipe with suction valve, deliver pipe with delivery
valve and prime mover which drives the pump.
1)FORWARD STROKE (SUCTION STROKE) : the piston
moves towards right, crank moves from 0° to 180 °. This
creates vacuum in cylinder on the left side of piston
causing the suction valve to open. The liquid enters the
cylinder and fills it.

19. 2)REVERSE STROKE (DELIVERY STROKE) : The piston
moves towards left, crank moves from 180 ° to 360 ° .
This causes increase of pressure in the left side of
cylinder. The delivery valve open and the liquid is forced
to delivery pipe
- The suction and delivery valves are non-return valve, they
opens or closes automatically according to pressure
difference across theme.

22.  In this pump, suction and delivery takes place
simultaneously on opposite sides of piston.
1) FORWARD STROKE : The piston moves toward
left side of cylinder, the liquid is sucked from sump
through suction valve (SA) .At this moment, the liquid on
right side of piston is compressed, the delivery valve (DB)
opens and liquid is discharged through this valve.

23. 2) REVERSE STROKE : the piston moves towards left side
of cylinder, the liquid is sucked from sump through
suction valve SB .At this moment, the liquid on left side of
piston is compressed and delivered through valve DA.
The double acting pump give more uniform discharge
than single acting pump, as fluid is delivered in both
strokes of piston.

25. A hand operated plunger pump consists of plunger,
stuffing box, suction valve, delivery valve and handle. The
pump is operated by handle. In order to prevent the leakage
of the liquid, the stuffing box, gland and packings are used.
Non-return valves are fitted at the suction and delivery
pipes preventing back flows.
1)Intake stroke: Plunger moves up, vacuum is created in the
cylinder, suction valve opens and liquid enters into cylinder.
2)Discharge stroke: Plunger moves down, suction valve
closes and delivery valve opens through which high pressure
liquid is delivered to the delivery pipe.

27. A bucket pump is single acting vertical reciprocating
pump. It consists of an open cylinder and a piston with
bucket type valve. A bucket type valve works as a non-return
valve.
1)Intake stroke: Piston moves up the bucket valve
remains closed. During this stroke liquid enters into the
cylinder through suction valve. Simultaneously, the liquid
above the bucket is forces into delivery pipe through
delivery valve.
2)Discharge stroke: Piston moves down, the bucket valve
open. In this stroke neither suction nor delivery of liquid
takes place, but the liquid which previously sucked in
cylinder moves on upper side of piston.

29. 1)Discharge(Q)
Q=Volume displaced in delivery stroke x No. of cycle per
second
Q=LA x (N/60) For single acting pump.
Q=LA x (2N/60) For double acting pump.
L=Length of stroke , A=Cross sectional area of
piston.
N=speed of pump in rpm

30. 2) Power required to drive pump:
P=Discharge x Pressure to be developed
= Q x ρgHm
Considering the frictional losses and leakage losses, the
power required by pump is as,
P= ρgQHm/ηP x 1000 kW
Power required at motor shaft to drive the pump
P= ρgQHm/ηo x 1000 kW

31. 3)Co-efficient of discharge(Cd):
It is the ratio of actual discharge to theoretical
discharge. Cd=Qa/Q.
4)Slip:
It is the measure of return of liquid through the valve or the
leakage of liquid from the delivery to the suction end.
Slip=Q-Qa

32. In case of single acting pump, the flow in delivery pipe as
well as in suction pipe is not continuous. In double acting or
multi cylinder pump, the flow is continuous but velocity vary
in suction as well as delivery pipe.
The main objectives to use air chamber in single acting
reciprocating pumps are as follows:-

33. i) To obtain a continuous supply of liquid at a uniform rate.
ii) To save a considerable amount of work in overcoming
the frictional resistance in the suction and delivery pipe.
iii) To run the pump at a high speed without cavitation or
separation.
Air chamber is fitted to the suction pipe and to the delivery
pipe at a point close to the cylinder of a single acting
reciprocating pump. The top of the air chamber contains
compressed air which can contract or expand.
The chamber has an opening at its base through which the
liquid may flow in to or out of it.

34. During delivery stroke, suction
valve gets closed and flow from
the suction pipe is taken into the
air chamber fitted on suction
side of the cylinder where it is
temporarily stored. Similarly
during suction stroke, delivery
valve is closed but the delivery
of liquid too the discharge tank
is continuous by liquid
discharged form air chamber
fitted on discharge side.
Thus the air chamber works as a
intermediate reservoir
maintaining constant discharge
by maintaining constant velocity
of flow in suction and delivery
pipe.

35. If mechanical energy is converted into pressure energy by
means of centrifugal force acting on fluid, for conveying
liquid from one place to other such device is called a
centrifugal pump.
Main Parts of Centrifugal pump:
1)Impeller 2)Casing
3)Suction Pipe 4)Delivery Pipe

36. 1)Impeller:-It is rotating part of a centrifugal pump and
increases kinetic energy of liquid . It is mounted on a shaft
which is coupled to shaft of a electric motor.
2)Casing:-It is an air tight passage surrounding the impeller
and is designed in such a way that the kinetic energy of the
liquid discharged at the outlet of impeller is converted into
pressure energy before the delivery pipe. Types of casing:
i)Volute ii)Vortex iii)Casing with guide blades.
3)Suction pipe:-It is a pipe whose one end is connected to the
inlet of the pump and other end dips into liquid in a sump.
4)Delivery pipe:-A pipe whose one end is connected to the
outlet of the pump and other end is extended to deliver the
liquid at a required height is known as delivery pipe.

37. • According to types of Casing:-
1)Volute 2)Vortex 3)Diffuser
• According to number of stages:-
1)Single stage 2)Multi stage

38.  In this type of C pump,
impeller is surrounded by
the spiral casing know as
volute type .
 Volute chamber provides
a gradual increase in area
to discharge pipe .
 It is useful for effective
conversion of kinetic
energy of water coming
from impeller into
pressure energy.

39.  This pump is modified
type of volute casing.
 In this casing circular
chamber is inserted
between the impeller and
volute chamber.
 It is formed a
combination of spiral and
circular chamber
 It is also known as
“Whirlpool” chamber

40.  In this pump, impeller is
surrounded
 By a series of guide plates
mounted on a ring which is
known as diffuser.
 Velocity of water falls and the
pressure increases.
 In this type of pump more
pressure head is developed
compare to vortex type and
volute type pump.
 It has higher efficiency.

41.  If the pump has only one impeller then the pump is called
Single Stage Pump.
 It can not produce sufficient high pressure head efficiently.
 It is mostly used for lower head and lower discharge.

42.  Multi staging is done by connecting impellers in series and
parallel.
1)Impeller in series:-
 If the pump has more then one impeller and all the
impellers are keyed to a single shaft arranged serially one
after the other and the enclosed in the same casing is known
as impeller in series.
 It is used for high working pressure head.

43. 2) Impeller in parallel:-
 In this case impellers are arranged in parallel.
 It can be done by mounting one impeller on each shaft and
keeping the shafts parallel to one other.
 This pump is used where high discharge is required.

44.  The priming is an operation of filling passage ways (suction
pipe, casing and delivery pipe upto delivery valve) from
outside source with the liquid to be raised before starting the
pump.
Method of priming :
 Manually
 Priming with vacuum pump
 Priming with jet pump
 Priming with separator

45.  In this method of priming water is poured in the pump
through priming funnel as fig.
 When priming is being done, an escapes through air vent
valve.
 When all air is exhausted from the casing, suction pipe
and portion of delivery pipe, the water will flow out
through vent valve, indicating that priming is completed.
The air vent valve is closed once the priming is
completed.

47.  In this method, the small size reciprocating pump is used
to priming the main centrifugal pump. The suction line of
reciprocating pump is connected to the delivery line of
main centrifugal pump.
 When manually operated reciprocating pump is started,
this pump lifts the water from sump to suction line , casing
and portion of delivery line of centrifugal pump. If now
centrifugal pump is started , it will able to deliver the
water to desired level.

49.  In this method , water available at high head is allowed to
flow through a nozzle.
 The nozzle is so designed that at the jet outside the nozzle
the pressure is less than the atmospheric pressure so it is
possible to suck water from the sump.
 The jet pump is generally fixed in suction pipe of
centrifugal pump near the sump level.

51.  In this method, air separator is provided on the delivery of
pump and bent suction pipe portion is provided on the
delivery side of pump and bent suction pipe portion is
provided at the inlet of the pump.
 When the pump is started, the liquid in bent suction pipe
along with the air from rest of suction pipe is sucked into
impeller and is delivered to separator.
 Since head developed initially is not sufficient, no liquid is
delivered at delivery end.

53. Reciprocating pump Centrifugal pump
Work on principal of positive
displacement.
Work on principle of roto-dynamic.
Efficiency is low. Efficiency is high.
It produce much noise. Smooth operation without noise.
It is used only for lifting pure
It is used for lifting highly
water or loss viscous liquids.
viscous liquids.
Initial and maintenance cost is
high.
Initial and maintenance cost is
less compare to reciprocating
pump.

54.  It is a positive displacement pumps. It consists of gears,
vanes, lobes, screws, cams etc.
 CLASSIFICATION OF ROTARY PUMPS :
 Gear pump
 Vane pump
 Screw pump

55.  It consists of two or more gears which mesh each other.
The rotation of these gears provides pumping action.
 As shown fig two spur gears in mesh with each other and
one of the gear is driving gear and other driven gear. The
mechanical contact between the gear teethes and crasing
seal space between the teeths. The fluid fills the gear
space, forming closed chambers with the casing.

56.  When pump is primed, the liquid fills the space between
the teethes of gears at the suction side. When driving gear
rotates, other meshing gear rotates opposite direction. A
negative pressure is created on the suction side due to
rotation of gears. Due to pressure diffrence in fluid tank
and suction pipe causes the fluid run from tank to pump.

57.  It consists of stationary casing and a cylindrical rotor. The
cylindrical rotor contains the sliding vanes which fitted to
the radial grooves of rotor as fig. The rotor is mounted
eccentrically in relation to cylindrical casing. The vanes
are free to move away from the centre of the rotor due to
the spring action or due to gravity and centrifugal force of
rotation. These makes tight contact between vanes and
casing during rotation.
 When the rotor rotates, the liquid enters from the suction
side is entrapped in the pocket between the vanes and
casing. This liquid is carried on by the vanes and finally
discharged to the delivery side.

59.  Screw pump are special type of rotary positive
displacement pumps. It consists of pair of screws, one of
the screw rotor drives other screw rotor in the stationary
casing as fig.
 The liquid is carried between screw threads in pair of
screws rotates.

61. Pump Application
Piston pump For low head and more discharge.
Plunger pump For high head and less discharge and
for denser liquids.
Bucket pump For low head and suitable for manual
operation.
Centrifugal pump For continuous flow, high discharge
and low head
Multi stage centrifugal pump(Parallel) High discharge
Multi stage centrifugal pump(series) For high head
Rotary pump For viscous fluid like lubricating oil

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