This set of Hydraulic Machines Multiple Choice Questions & Answers (MCQs) focuses on “Discharge of Reciprocating Pumps”.
1. In a positive displacement pump, what gets displaced?
a) Fluid
b) Volume
c) Pressure
d) Temperature
View Answer
Explanation: Reciprocation pump is a type of positive displacement pump. It has a piston pump, plunger and diaphragm. Reciprocating pumps have a good life provided that they are not left untouched. The fluid gets displaced in a positive displacement pump.
2. What happens to the reciprocating pump when left untouched?
a) Efficiency decreases
b) Wear and tear
c) Surface expansion
d) Pressure change
View Answer
Explanation: When left untouched over a period of time, the reciprocating pump undergoes wear and tear. Reciprocating pumps have a good life provided that they are not left untouched.
3. Positive displacement pumps are capable of developing ______ pressures, in _______ suction pressure.
a) High, low
b) Low, high
c) High, high
d) Low, low
View Answer
Explanation: Positive displacement pumps are capable of developing high pressures, in low suction pressure. Reciprocation pump is a type of positive displacement pump.
4. When is a reciprocating pump used?
a) When quantity of liquid is small
b) When quantity of liquid is large
c) To pump high pressure
d) To pump low pressure
View Answer
Explanation: Reciprocating pump is more favourable for small liquid quantities. As the chamber in the liquid is trapped, it has a stationary cylinder which contains a piston and a plunger.
5. Positive displacement pumps are also called as__________
a) Constant pressure pump
b) Pressure drag pumps
c) Constant volume pumps
d) Constant head pumps
View Answer
Explanation: Positive displacement pumps are also called as constant volume pumps. Positive displacement pumps are capable of developing high pressures, in low suction pressure. Reciprocation pump is a type of positive displacement pump.
6. At high pressure, the voids can generate ______
a) Drag force
b) Mass density
c) Shock waves
d) Flow speed
View Answer
Explanation: At high pressure, the voids can generate shock waves. Cavitation usually occurs due to the changes in pressure. The pressure change is so rapid that it leads to formation of liquid free layers or cavities that start to affect the overall performance.
7. In centrifugal pumps, their capacity is affected due to___________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Pressure
View Answer
Explanation: In centrifugal pumps, their capacity is affected due to the presence of pressure that works against the pump they operate.
8. A quantity of fluid that leaks from a higher pressure discharge to a lower pressure discharge is called______
a) Slip
b) Heat
c) Friction
d) Enthalpy
View Answer
Explanation: Slip is defined as the quantity of fluid that leaks from a higher pressure discharge to a lower pressure discharge.
9. Positive displacement pumps regulate the flow by varying its ________
a) Drag force
b) Cyclic stress
c) Shock waves
d) Flow speed
View Answer
Explanation: Positive displacement pumps regulate the flow by varying its flow speed. This happens by the pump or by the process of recycling. Positive displacement pumps are also called as constant volume pumps.
10. Positive displacement pumps are divided into two types.
a) True
b) False
View Answer
Explanation: Yes, Positive displacement pumps are divided into two types. The two types are reciprocating pumps and rotary pumps. Both these pumps differ in their working and construction.
11. Centrifugal pump is less efficient than a reciprocating pump because of its _______
a) Temperature
b) Speed
c) Heat
d) Cost
View Answer
Explanation: Centrifugal pump is less efficient than a reciprocating pump because of its cost of maintenance. Cost factor plays an important role in determining the efficiency.
12. Simplest example of single acting reciprocating pump is _______
a) Mineral ores
b) Whirl wheels
c) Bicycle tires
d) Syringe
View Answer
Explanation: Simplest example of single acting reciprocating pump is a syringe. Power operated pump in which only one side engages the fluid displacement is called as single acting reciprocating pump. It consists of piston in only one side of the fluid being displaced.
13. Rotary pumps do not function well under _______
a) High Vaporisation
b) High Sedimentation
c) High viscosity
d) Excavation
View Answer
Explanation: Rotary pumps do not function well under high viscosity fluid. Theses pumps are normally limited to services during the increase of such parameters.
14. The parameter that disturbs the working of the rotary pump is______
a) High Vaporisation
b) High Sedimentation
c) Low flow rate
d) Excavation
View Answer
Explanation: The parameter that disturbs the working of the rotary pump is low flow rate and a high viscosity. Theses pumps are normally limited to services during the increase of such parameters.
15. In a double acting reciprocating pump, the piston carries suction and expulsion at the same time.
a) True
b) False
View Answer
Explanation: Yes, it is true. In a double acting reciprocating pump, the piston carries suction and expulsion at the same time. It consists of piston in both the side of the fluid being displaced.
Sanfoundry Global Education & Learning Series – Hydraulic Machines.
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