1. What is
meant by Pump?
A pump is
device which converts mechanical energy into hydraulic energy.
2. Define a centrifugal pump
If the mechanical energy is
converted into pressure energy by means of centrifugal force cutting on the
fluid, the hydraulic machine is called centrifugal pump.
3. Define suction head (hs).
Suction head is the vertical
height of the centre lines of the centrifugal pump above the water surface in
the tank or pump from which water is to be lifted. This height is also called
suction lift and is denoted by hs.
4. Define delivery head (hd).
The vertical distance between the
center line of the pump and the water surface in the tank to which water is
delivered is known as delivery head. This is denoted by hd.
5. Define static head (Hs).
The sum of suction head and
delivery head is known as static head. This is represented by 'Hs' and is
Hs = hs+
main components of Centrifugal pump.
Suction pipe,strainer & Foot valve
iv) Delivery pipe & Delivery valve
7. What is meant by Priming?
The delivery valve is closed and the suction pipe,
casing and portion of the delivery pipe upto delivery valve are completely
filled with the liquid so that no air pocket is left. This is called as
8. Define Manometric head.
It is the
head against which a centrifugal pump work.
9. Describe multistage pump with
impellers in parallel b. impellers in
series. In multi stage centrifugal pump,
a. when the
impellers are connected in series ( or on the same shaft) high head can be
b. When the
impellers are in parallel (or pumps) large quantity of liquid can be
10.. Define specific speed of a centrifugal pump
The specific speed of a
centrifugal pump is defined as the speed of a geometrically circular pump which
would deliver one cubic meter of liquid per second against a head of one meter.
It is denoted by 'Ns'.
11. What do you understand by characteristic
curves of the pump?
Characteristic curves of
centrifugal pumps are defined those curves which are plotted from the results
of a number of tests on the centrifugal pump.
12. Why are centrifugal pumps used sometimes in
series and sometimes in parallel?
The centrifugal pumps used sometimes in series
because for high heads and in parallel for high discharge
13.Define Mechanical efficiency.
t is defined as the ratio of the power actually
delivered by the impeller to the power supplied to the shaft.
14. Define overall efficiency.
It is the
ratio of power output of the pump to the power input to the pump.
15. Define speed ratio, flow ratio.
Speed ratio: It is the ratio of peripheral speed
at outlet to the theoretical velocity of jet corresponding to manometric head.
Flow ratio: It is the ratio of the velocity of
flow at exit to the theoretical velocity of jet corresponding to manometric
Mention main components of Reciprocating
# Piton or
and delivery pipe
# Crank and
17.. Define Slip of reciprocating pump. When the
negative slip does occur?
The difference between the theoretical discharge and actual
discharge is called slip of the pump.
But in sometimes actual discharge may be higher then
theoretical discharge, in such a case coefficient of discharge is greater then
unity and the slip will be negative called as negative slip.
18. What is indicator diagram?
Indicator diagram is nothing but a graph plotted
between the pressure head in the cylinder and the distance traveled by the
piston from inner dead center for one complete revolution of the crank
19. What is meant by Cavitations?
It is defined phenomenon of formation of vapor bubbles of a
flowing liquid in a region where the pressure of the liquid falls below its vapor
pressure and the sudden collapsing of theses vapor bubbles in a region of high
20. What are rotary pumps?
Rotary pumps resemble like a centrifugal pumps in
appearance. But the working method differs. Uniform discharge and positive
displacement can be obtained by using these rotary pumps, It has the combined
advantages of both centrifugal and reciprocating pumps.