Waste Water Engineering Multiple Choice Questions on “Pumps & Pumping Stations – 1”.
1. An apparatus for raising, driving or compressing fluids or gases is called _________
a) Piston
b) Pump
c) Compressor
d) Force drive
Answer: b
Clarification: A pump is a device used to transfer or force the liquid or gas against gravity. There are different types of pumps based on the requirements and the pumps are designed for different loads.
2. ________ pumps produce a head and a flow by increasing the velocity of the liquid with the help of the rotating vane impeller.
a) Displacement pumps
b) Positive pumps
c) Centrifugal pumps
d) Rotating pumps
Answer: c
Clarification: Centrifugal pumps produce a head and a flow by increasing the velocity of the liquid with the help of the rotating vane impeller. Centrifugal pumps include radial, axial and mixed flow units.
3. What are the pumps that operate by alternately filling a cavity and then displacing a given volume of liquid called?
a) Centrifugal pump
b) Rotating pump
c) Positive displacement pump
d) Roto-dynamic pump
Answer: c
Clarification: A positive displacement pump alternately fills a cavity and then displaces a given volume of liquid. For each cycle, this pump delivers a constant volume of liquid independent of discharge pressure or head.
4. The two types of pumps behave very differently regarding pressure head and flow rate.
a) True
b) False
Answer: a
Clarification: There are two types of basic pumps. One is the centrifugal pump and the other one is positive displacement pump. Centrifugal pump is also called as a roto-dynamic pump. These two pumps behave very differently with respect to flow rates and pressure head.
5. A steam pump is a type of centrifugal pump.
a) True
b) False
Answer: b
Clarification: There are different types of centrifugal pumps such as end suction pumps, in-line pumps, axial-flow pumps, regenerative pumps, etc. Steam pump is a type of positive displacement pump.
6. In a centrifugal pump, the flow is _______ when the viscosity is increased.
a) Reduced
b) Increased
c) Greater
d) Same
Answer: a
Clarification: In a centrifugal pump, the flow is reduced when the viscosity is increased. This is because the viscosity of any fluid restricts its capacity to flow easily. On thickening the solution or liquid, the flow is reduced.
7. What are the pumps with one or more impellers called?
a) ANSI process pumps
b) API process pumps
c) Centrifugal pumps
d) Positive displacement pumps
Answer: c
Clarification: The general name for pumps with one or more impellers is called centrifugal pumps. Many types and configurations of centrifugal pumps are used for different applications.
8. Why are booster pumps used?
a) Higher flow
b) Boost pressure
c) Chop solids
d) Maintain flow
Answer: b
Clarification: Booster pumps are used to further boost the pressure in a system. It may be in-line circulator, horizontal split case, or vertical turbine in a can type of pump. Chopper Pumps are designed to chop up solids and stringy material as it pumps.
9. Why are cryogenic pumps used?
a) Boost pressure
b) Handle low temperature liquids
c) Handle high temperature liquids
d) Pump small quantities of liquids
Answer: b
Clarification: Cryogenic pumps are used to handle very low temperature liquids. Booster pumps are used to further boost the pressure in a system. Drum pumps are used to pump out small quantities of liquid of out of drums and carboys.
10. End suction pumps are the common type of _________ pumps.
a) Drum pumps
b) Centrifugal pumps
c) Positive displacement pumps
d) Grinder pumps
Answer: b
Clarification: End suction pumps are the common type of centrifugal pump. It has a horizontal shaft with an overhung impeller. The flow goes in the end of the casing, and out the top.
11. Which pump among the ones mentioned below can be located above the suction reservoir without an external priming system?
a) Slurry pumps
b) Self-priming pumps
c) Submersible pumps
d) Trash pumps
Answer: b
Clarification: Self-Priming pumps are a type of centrifugal that can be located above the suction reservoir without an external priming system. It has an end suction configuration but an enlarged case to support priming.
12. Which type of pump is designed to handle rocks and other solids?
a) Trash pumps
b) Submersible pumps
c) Slurry pumps
d) Self-priming pumps
Answer: a
Clarification: Trash pumps are a type of submersible centrifugal pump designed to handle rocks and other solids while dewatering. It is used in dewatering construction sites, mines, and utility pits.
13. Which type of pump should be used in order to handle low viscosity fluids?
a) Centrifugal Pump
b) Displacement Pump
c) Submersible Pump
d) End Suction Pump
Answer: a
Clarification: Centrifugal pumps can pump liquids which are of low viscosity. It cannot handle liquids such as oil. The liquid that is pumped by centrifugal pumps should be free from air.
14. Which type of pump should be selected in order to pump the sewage from a septic tank to the water treatment system?
a) Vertical Sump Pump
b) Progressive Cavity Pump
c) Submersible Pump
d) Screw Pump
Answer: c
Clarification: Submersible pumps are used to handle liquids with solids. Also, these are non-clog pumps which are fully or partially submerged in the tanks. In cases where the pump is partially submerged the motor is above the water level and the motor is connected to the pump by an extended shaft.
15. In an activated sludge process which type of pump is used to recirculate the sludge?
a) Booster Pump
b) Centrifugal Pump
c) Vane Pump
d) Vertical Turbine Pump
Answer: b
Clarification: The activated sludge does not contain any solids. Also, it is not very viscous. Hence a centrifugal pump can be used for this application.
16. Which type of pump is used while handling the sludge disposal system?
a) Screw Pump
b) Multistage Pump
c) Self-priming Pump
d) Vertical Pump
Answer: a
Clarification: Screw Pumps utilize intermeshing screws driven by timing gears in order to move the viscous liquids. These pumps are used to pump thick liquids. Hence it is suitable to handle sludge.