# Environmental Engineering Questions and Answers – Centrifugal Pump

This set of Environmental Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Centrifugal Pump”.

1. The impeller in the volute pump is surrounded by _____________
a) Discharge pipe
b) Throat
c) Suction pipe
d) Volute chamber

Explanation: The impeller in the volute pump is surrounded by a spiral shaped casing called as volute chamber. The shape of the casing is such that the sectional area of flow around impeller increases from the tongue to delivery tube.

2. The advance version of volute chamber is designed by _____________
a) V. Richardson
b) J. Thomson
c) Darcy Weisbach
d) Bernoulli

Explanation: The advance version of volute chamber is designed by J. Thomson where a circular chamber called vortex chamber is provided between the impeller and the volute chamber.

3. Consider the following statements regarding vortex chamber.
i. Reduce the velocity of the pump
ii. Convert pressure energy into kinetic energy
iii. Decrease the efficiency of the pump
Which of the above statement is correct?
a) Only i
b) Only ii
c) Only iii
d) i, ii, iii

Explanation: The vortex chamber reduces the velocity of pump, converts the kinetic energy into pressure energy and increase the efficiency of the pump.

4. A diffuser pump is also called as _______ pump.
a) Reciprocating pump
b) Volute pump
c) Turbine pump
d) Rotary pump

Explanation: A diffuser pump is a reverse pump, so it is also called a turbine pump. It contains a series of guide vanes surrounding the impeller.

5. Depending on the number of impellers, the centrifugal pump is divided into ______________ types.
a) Two
b) Three
c) Four
d) Six

Explanation: The centrifugal pump is divided into a single stage and multistage pump depending on the number of impellers.

6. The each stage in centrifugal pump increase the head by ______________
a) 10m
b) 20m
c) 30m
d) 60m

Explanation: The each stage in centrifugal pump increase the head from 30 to 45m. There can be six stages in a centrifugal pump.

7. Radial flow pump is a pump classified on the basis of _____________
a) Direction of flow
b) Number of impellers
c) Number of entrances to the impeller
d) On the basis of shaft

Explanation: Depending on the basis of the direction of flow, the centrifugal pump is divided into the radial flow pump, mixed flow pump and axial flow pump.

8. Which of the following type of pump is based on the number of entrances to the impeller?
a) Single stage pump
b) Single suction pump
c) Mixed flow pump
d) Horizontal pump

Explanation: Based on the number of entrances to the impeller, the centrifugal pump is divided into single suction and double suction pump. In a single suction pump, the liquid enters from one side of the impeller.

9. The specific speed of a pump is given by _____________
a) NQ1/2 / H2
b) NQ1/2 / H3/4
c) NQ / H3/4
d) NQ 1/2 / H1/4

Explanation: The specific speed of a centrifugal pump is given by NQ1/2 / H3/4 Where, N is the rotational speed in rates per minute, Q is the discharge in litres/Sec and H is the head in metres.

10. When the specific speed of the pump is <2600, the type of pump is _____________
a) Reciprocating pump
b) Centrifugal pump
c) Mixed flow pump
d) Axial flow pump

Explanation: The specific speed of the pump is given by NS = NQ1/2 / H3/4 and when NS > 2600, the type of pump is centrifugal pump.

Sanfoundry Global Education & Learning Series – Environmental Engineering.

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