250+ TOP MCQs on Pumps and Answers

Dairy Engineering Multiple Choice Questions on “Pumps”.

1. Which of the following centrifugal pumps has higher specific speed than the others?
a) Axial flow
b) Radial flow
c) Mixed flow
d) All centrifugal pumps have same specific speed
Answer: a
Clarification: An axial flow pump is a type of centrifugal pump that uses an impeller with vanes that direct the flow axially. Axial flow pumps create less pressure as compared to radial flow centrifugal pumps, but they can produce much higher flow rates.

2. Pump transfers the mechanical energy of a motor or of an engine into _________ of a fluid.
a) Pressure energy
b) Kinetic energy
c) Either pressure energy or kinetic energy
d) Pressure energy, kinetic energy or both
Answer: d
Clarification: A pump is a machine used to convert mechanical energy (shaft movement) into hydraulic energy. Hydraulic energy could be in the form of pressure energy or kinetic energy or a combination of both. An electrical motor usually supplies the mechanical energy to the pump.

3. Which of the following is NOT a type of positive displacement pumps?
a) Reciprocating pump
b) Rotary displacement pump
c) Centrifugal pump
d) None of the mentioned
Answer: c
Clarification: Centrifugal pump is not a positive displacement pump. Reciprocating pumps move liquid by means of a constant back-and-forth motion of a piston, plunger, or diaphragm within a fixed volume or cylinder. Reciprocating pumps can handle viscous and abrasive fluids. They are low-speed machines when compared with centrifugal and rotary.

4. Rotary displacement pumps are suitable for handling ________
a) Oils
b) Gritty liquids
c) Both oils as well as gritty liquids
d) Granules
Answer: a
Clarification: Positive displacement rotary pumps rely on fine clearances between moving parts for their efficient operation. When used for lubricating oil and hydraulic systems, rotary displacement pumps benefit from the sealing effect and provision of lubrication between parts.

5. Which of the following is/are not example/s of rotary displacement pumps?
a) Gear pump
b) Vane pump
c) Rotary piston pump
d) Centrifugal pump
Answer: d
Clarification: Rotary-type positive displacement: internal gear, screw, shuttle block, flexible vane or sliding vane, circumferential piston, and flexible impeller, helical twisted or liquid-ring pumps.

6. ___________ pump is also called as velocity pump.
a) Reciprocating
b) Rotary displacement
c) Centrifugal
d) Screw
Answer: c
Clarification: Centrifugal pump is commonly known as velocity pump. A centrifugal pump imparts velocity to a liquid. This velocity energy is then transformed largely into pressure energy as the liquid leaves the pump.

7. Discharge capacity of the reciprocating pump is __________ that of the centrifugal pump.
a) Higher than
b) Lower than
c) Same as
d) Unpredictable
Answer: b
Clarification: The capacity of a pump has two components, the pump discharge rate and the discharge pressure. The discharge rate is normally measured in gallons per minute (gpm) in English units or liters per second (lps) in metric units. Discharge capacity of the reciprocating pump is less that of the centrifugal pump.

8. Which pump is more suitable for an application where very high pressure is required to be developed at moderate discharge?
a) Reciprocating pump
b) Centrifugal pump
c) Turbine
d) None of the mentioned
Answer: a
Clarification: Reciprocating pumps are generally designed to pump in low flow, high head applications. One of the most extreme of these applications is water jet cutting, where only a few gallons pass through the pump per minute, but exceed pressures of 10,000 PSI.

9. The process of filling the liquid into the suction pipe and pump casing up to the level of delivery valve is called as _________
a) Filling
b) Pumping
c) Priming
d) Leveling
Answer: c
Clarification: Most pumps are not self-priming. In other words, the pump casing must be filled with liquid before the pump is started, or the pump will not be able to function. In case the pump casing gets filled with vapors or gases, the pump impeller becomes gas-bound and incapable of pumping.

10. The volute pumps and vortex volute pumps are __________ pumps with _________ shaft.
a) Multistage, horizontal
b) Multistage, vertical
c) Single stage, horizontal
d) Single stage, vertical
Answer: c
Clarification: The volute pumps and vortex pumps are single stage pumps with horizontal shaft. They are both a type of centrifugal pumps.

11. Most widely used sanitary pumps in the dairy industry are?
a) Centrifugal pump
b) Liquid ring pump
c) Positive displacement pump
d) Suction pump
Answer: a
Clarification: Typical dairy pumps are the centrifugal, liquid-ring and positive displacement pumps. The three types have different applications. The centrifugal pump is the type most widely used in dairies.

12. Main application of centrifugal pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
Answer: a
Clarification: The centrifugal pump can be used for pumping of all liquids of relatively low viscosity which do not require particularly gentle treatment. It can also be used for liquids containing relatively large particles, provided of course that the particle size does not exceed the dimensions of the impeller channel.

13. Main application of liquid ring pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
Answer: b
Clarification: Liquid-ring pumps for the dairy industry are used where the product contains large quantities of air or gas, and where centrifugal pumps therefore cannot be used. The clearances between impeller and casing are small, and this type of pump is therefore not suitable for handling abrasive products.

14. Main application of positive displacement pump is in which of the following?
a) Low viscosity products
b) Heavily aerated liquids
c) Gentle treatment with high viscosity
d) Water treatment
Answer: c
Clarification: This type of pump has 100% volumetric efficiency (no slip) when the viscosity exceeds approximately 300 cP. Because of the sanitary design and the gentle treatment of the product, this type of pump is widely used for pumping cream with a high fat content, cultured milk products, curd/whey mixtures, etc.

15. Which of the following pump suitable for handling AMF in the dairy industry?
a) Centrifugal pump
b) Liquid ring pump
c) Diaphragm pump
d) Peristaltic pumps
Answer: d
Clarification: In Peristaltic pumps, during rotation, the medium (liquid or gas) inside the hose is transported to the lower outlet connection. This creates a vacuum on the suction side, and the product is drawn into the pump. The pump is self-priming and is therefore suitable for emptying barrels with juice concentrates and anhydrous milk fat (AMF).