PUMPS SUMARY
1. The moving part of a centrifugal pump is a…………
A. Impeller
B. Diffuser
C. Volute
D. Suction nozzle
2. Throttling the delivery valve of a pump results in
A. Increase head
B. Increase power
C. Decrease head
D. Both A and B
3. Installing larger diameter pipe in pumping system results in reduction in
A. Static head
B. Frictional head
C. Both A and B
D. None of the above
4. What is the impact on flow and pressure when the impeller of a pump is trimmed?
A. Flow decreases with increased pressure
B. Both flow and pressure increase
C. Both flow and pressure decrease

D. None of the above

5. Friction losses in a pumping system is
A. Proportional to 1 / Q
B. Proportional to 1 / Q2
C. Proportional to 1 / Q3

D. Proportional to 1 / Q4

6. For high flow requirement, pumps are generally operated in

A. Parallel
B. Series
C. Both A and B
D. None of the above
7. The operating point in a pumping system is identified by
A. Point of intersection of system curve and efficiency curve
B. Point of intersection of pump curve and theoretical power curve
C. Point of intersection of pump curve and system curve
D. Cannot be determined by the pump characteristic curves
8. If the speed of a centrifugal pump is doubled, its power consumption increases by _________ times
A. No change
B. Two
C. Four
D. Eight
9. Using the affinity laws in the centrifugal pump, if the speed of a centrifugal pump is doubled, its head increases
by _________ times
A. 2
B. 4
C. 6
D. 8
10. In centrifugal pumps, a change in the diameter of the impeller can reducing the diameter to about
____________ of maximum size
A. 25%
B. 50%
C. 75%
D. None of the above
11. Small by-pass lines are sometimes installed to
A. Control the flow rate
B. Control the pump delivery head
C. Reduce pump power consumption

D. Prevent the pump from running at zero flow
12. Centrifugal pumps have a minimum operating flow rate, below which the pump should not be run for long
periods without sacrificing reliability. From the standpoint of long term reliability and operating efficiency, it is
the best to operate pumps close to
A. Maximum head
B. Maximum flow rate
C. Minimum flow rate
D. Their BEP
13. When packing is used to seal the shaft on a centrifugal pump:
A. the packing will prevent the pump from getting too hot
B. the packing must be adjusted daily
C. the packing will wear out quickly
D. some leakage is necessary along the shaft for good lubrication
14. The capacity of a pump is usually rated:
A. In GPM
B. In SCFM
C. in foot pounds per inch
D. in metric measure
15. Which of the following measures pump capacity?


A. Barrels per day
B. Pounds per square inch
C. Static head
D. Standard cubic feet per minute
16. In a centrifugal pump, normally ring packing is lubricated by:
A. a gravity flow oil system
B. a drip oil system

C. a mechanical lubricator


D.The liquid being pumped
17. Normally, ring packing is lubricated by:
A. the liquid being pumped
B. outside oil systems
C. mechanical lubricators
D. hand
18. Which of these will result in an increase in flow from a pump?
A. Decreasing the impeller diameter
B. Increasing the RPM of the shaft
C. Increasing the required NPSH
D. Increasing the length of the shaft
19. In a centrifugal pump, liquid flows:
A. from the rim of the impeller to the suction eye of the impeller
B. from the outlet of the vanes to the suction eye of the impeller
C. from the suction eye to the inlet piping
D. From the suction eye to the rim of the impeller
20. Casing wear rings of a centrifugal pump:
Answer: must allow no flow from the impeller back to the suction
21. If the liquid level to be pumped by a centrifugal pump is below the pump level:
A. the pump will not pump
B. the pump will only pump the liquid to a height equal to the liquid level below the pump
C. the pump must be primed before start-up
D. the pump must be lowered so that it is positioned below the liquid to be pumped
22. If the suction head of a pump is 8 feet and the vapor pressure of the liquid in the pump (changed to equivalent
head) is 9 feet, the liquid will:
A. Condense
B. fill the casing completely
C. burst the pump casing
D. vaporize

23. Which of these pump arrangements increases head?

A. A
B. B
C. Neither, since head is not related to pump line-ups
24. Which of the pump line-ups below will create the most head?

A. A

B. B

C. Not enough information is given to make this evaluation

D. Since two equal sized pumps are used, the head will be the same for both line-ups
25. Which of the following is most likely to cause cavitation?

D. Both of them


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A. Worn bearings
B. Worn packing
C. Insufficient NPSH
D. Poor pump alignment
A multi-staged pump is used:
A. only for pumping heavy fluids
B. when you need increased capacity
C. only for pumping light fluids
D. only when higher pressure is required
Cavitation in a pump:
A. does little damage if the pump is kept running
B. means the pump casing has a cavity (or hole) in it
C. is the continual forming and collapsing of vapor bubbles in the liquid in a pump
D. is caused by corrosion
Cavitation in a pump creates so many undesirable effects out of the following, which is not an undesirable
effect created by cavitation?
A. Decrease in effect
B. Increase in thrust
C. Develops noise
D. Develops high pressure
If a centrifugal pump is operated too long with the discharge valve closed:

A. the pump may overheat, causing a vapor lock
B. the pump bearings will overheat and begin to wear
C. the discharge valve is likely to become damaged
D. the discharge valve will work its way open
When the discharge of one pump is fed into another pump's suction:
A. the pump will soon cavitate
B. the pumps are in parallel
C. the pumps are said to be operating in series
D. an increase in capacity and a decrease in discharge pressure will occur
Balancing drums are used on multi-stage pumps:
A. to reduce weight
B. to reduce axial thrust
C. to increase the total flow of liquid through the pump
D. to balance the speed of the driver to the speed of the pump
A multi-stage pump is used when you need:
A. increased capacity
B. increased head pressure
C. both increased capacity and higher head pressure
D. high velocity and lower pressure
Multi-stage centrifugal pumps are generally used for__________
A. high head
B. low head but high discharge
C. highly viscous liquid
D. slurries of high solid concentration
If the suction level is below the level of the pump, a centrifugal pump:
A. will not pump
B. will have to be primed before it will pump
C. will need to be lowered so that it will pump
D. None of these
A small amount of leakage between the packing and the shaft of a pump:

A. usually indicates that the wrong packing has been used


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B. should be stopped any leakage at all is too much
C. is necessary for proper lubrication
D. is an indication that a mechanical seal is needed
The speed of turbine-driven pumps can be controlled decreasing the speed of the pump will:
A. cause cavitation
B. increase the discharge pressure
C. increase the pump’s capacity
D. have the same effect as installing a smaller impeller
If a pump has lost its prime:

A. it must be replaced
B. it will need extensive repairs
C. it must be reprimed before it can be expected to pump again
D. it must be shut down long enough to cool off
If the pumps are taking suction from the same tank and pumping into a common discharge line:
A. neither pump will pump
B. they are said to be pumping in parallel
C. they will overpressure the discharge line
D. they are said to be pumping in series
To help eliminate axial thrust in large, multi-stage pumps, we often use:
A. sleeve bearings
B. wear rings
C. a balancing drum
D. rubber bumpers
The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the
pressure head at the …………………..
A. Discharge
B. Suction
C. suction minus vapor pressure of the liquid at suction temperature
D. discharge minus vapor pressure of the liquid at the discharge temperature
Net positive suction head (NPSH) of a centrifugal pump must be__________
A. greater than the vapour pressure of the liquid
B. less than the vapour pressure of the liquid
C. equal to the vapour pressure of the liquid
D. less than barometric pressure
To prevent pump from losing prime, foot valves provided in pumps are __________ valves
A. Relief
B. three/four way
C. pressure reducing
D. directional control

Head developed by a centrifugal pump depends on its________
A. Speed
B. impeller diameter
C. both speed and impeller diameter
D. neither speed nor impeller diameter
What causes cavitation in centrifugal pump?
A. High suction pressure
B. Low barometric pressure
C. Low suction pressure
D. High suction velocity
Answer: Low suction pressure
A centrifugal pump loses prime after starting. The reason of this trouble may be__________
A. incomplete priming
B. too high a suction lift
C. low available NPSH and air leaks in the suction pipe
D. all of these


46. A centrifugal pump designed for handling water (μ = 1 cp) will deliver __________ when pumping a thicker oil
(μ = 30 cp)
A. less head & capacity
B. more head
C. more capacity
D. less head & more capacity
47. When the water is warm, the height to which it can be lifted by a pump__________
A. decreases due to reduced viscosity
B. decreases due to reduced vapour pressure
C. increases due to increased vapour pressure
D. decreases due to increased frictional resistance
Answer: decreases due to reduced vapour pressure

48. Consider a centrifugal pump having a specific impeller diameter, fixed impeller speed pumping a liquid of
constant density at a particular discharge capacity with decrease in the capacity of the pump, the __________
decreases
A. NPSH required
B. BHP required by the pump
C. head of the liquid pumped
D. all of these
49. Cavitation in a centrifugal pump can be avoided by keeping the__________
A. inlet pressure high
B. outlet pressure low
C. inlet pressure low
D. outlet pressure high
50. The phenomenon occurring during pumping of a liquid solution containing dissolved gases, which may come
out of the solution giving rise to gas pockets, is termed as__________
A. Evaporation
B. Cavitation
C. Sublimation
D. Stripping
51. While starting a centrifugal pump, its delivery valve should be kept__________
A. Opened
B. Closed
C. either opened or closed ; it does not make any difference
D. either opened or closed; depending on the fluid viscosity
52. Purpose of relief valve in a reciprocating pump is to__________
A. protect the pump against developing excessive pressure
B. facilitate unidirectional flow of liquid
C. reduce the discharge pressure
D. control the rate of discharge
53. Function of air vessel provided in a reciprocating pump is to_________
A. reduce discharge fluctuation

B. reduce the danger of cavitation
C. avoid the necessity of priming
D. increase the pump efficiency
54. Cavitation occurs in a centrifugal pump when the suction pressure is__________
A. less than the vapour pressure of the liquid at that temperature
B. greater than the vapour pressure of the liquid at that temperature
C. equal to the vapour pressure
D. equal to the developed head
55. In centrifugal pumps, cavitation occurs, when pressure of the impeller eye or vane becomes__________
A. less than atmospheric pressure
B. more than liquid vapor pressure


C. less than liquid vapor pressure
D. more than atmospheric pressure
56. Cavitation can be prevented by……………..
A. suitably designing the pump
B. maintaining the suction head sufficiently greater than the vapour pressure
C. maintaining suction head = developed head
D. maintaining suction head lower than the vapour pressure
57. The capacity of a centrifugal pump can be increased by increasing the__________
A. impeller diameter or speed
B. Number of pumps and joining them in series
C. Number of pumps and joining them in parallel
D. all of these Answer
58. Look at this drawing to answer questions, what kind of impeller does this pump have?

Answer: Open impeller
59. Look at this drawing to answer questions, what kind of impeller does this pump have?


Answer: Semi-open impeller
60. Look at this drawing to answer questions. What is the name of X?

A. Total Head
B. Static Head
C. Friction Head
D. Flow rate
61. Look at this drawing to answer questions. What is the name of A & C?


A. Shaft and suction end
B. Shaft and discharge end
C. Shaft and casing D. Shaft and impeller
62. Look at this drawing to answer questions. Which is the centrifugal pump?

A. A and C
B. A and B
C. B and C
D. None of above
63. In centrifugal pump, where are the stuffing box and mechanical seals placed?
A. At suction end
B. At discharge end
C. Between centrifugal pump and electric motor
D. None of above
64. The energy placed into the water by a pump can be expressed as an increase in ____________and
increase in______________
A. Pressure head
B. Velocity head
C. Pressure head and velocity head
D. Pressure head and BEP

65. Look at this drawing to answer questions. What is the name of X?

A. Mechanical seal

B. Packing seal

C. Impeller

D. Volute


66. What are the basic types of maintenance?
A. Preventive and breakdown maintenance
B. Preventive and predictive maintenance
C. Preventive, predictive and breakdown maintenance
D. Other
67. In centrifugal pump, the Best Efficiency Point (BEP) is defined as
A. The most stable condition at which the pump can operate
B. The worst stable condition at which the pump can operate
C. The unstable condition at which the pump can operate
D. The most stable condition at which the pump can not operate
68. Consequently most centrifugal pump users will attempt to operate their pumps within a range of
A. 10% to 30% of the BEP
B. 30% to 50% of the BEP
C. 50% to 70% of the BEP
D. 70% to 120% of the BEP
69. Look at this drawing to answer questions, what number indicates the discharge line of this pump?

A. 1
B. 4

C. 8
D. 2
70. Look at this drawing to answer questions, what number indicates the wear rings on this pump?

A. 2
B. 3
C. 9
D. What number indicates the wear rings on this pump?
71. Look at this drawing to answer questions, what kind of impeller does this pump have?


A. Open
B. Close
C. Partially open
D. Turbine
72. Look at this drawing to answer Questions, The packing on this pump:

A. is a mechanical seal

B. is indicated by the number 3

C. is indicated by the number 9

D. is not shown in this drawing
73. Look at this drawing to answer Questions, The centrifugal pump shown here is:

A. a double suction pump
B. a double volute pump



C. a multi-stage pump
D. a single-stage pump
74. The specific gravity of a fluid is a comparison of the weight of a specific volume of the liquid with an equal
volume of:
A. oil at 60 °F
B. Hydrogen
C. Water
D. 30 wt oil
75. What is the total head produced by this pump?

A. 30
B. 20
C. 10
76. The 43 PSIG in this drawing measures:

D. 40

A. the pressure produced by liquid head
B. the pressure added by atmospheric pressure on the liquid
C. atmospheric pressure
D. the total force on the bottom of the tank
77. What is the absolute pressure on the tank pictured below?

A. 57.7 psia
B. 43.7 psia
C. 54.7 psig
D. 14.7 psia
78. High vapor pressure will be more of a problem in which of these pumps?



A. A

B. B

C. The problem is identical for both

D.Neither Vapor pressure will not affect the pumps, only the tanks
79. A lantern ring is:
A. a ring through which light passes to show flow
B. a metal cage about the size of a packing ring in the packing box
C. a rubber ring used to seal the casing head of a pump
D. Several light beams in a circle used to measure the level in a tank
80. Which of those drawings illustrates the principle of the centrifugal pump?

A. A
B. B
C. C
D. None of these
81. Vapors need energy to escape from liquid this energy comes from
A. Heat
B. Radiation
C. pumping action
D. Electricity
82. Potential energy is:
A. energy of motion
B. electrical energy
C. stored energy
D. nuclear energy
83. Which of the pumps pictured below is a centrifugal pump?


A. A
B. B
C. C
D. None of these
84. If an electric driver for a centrifugal pump persistently kicks out or trips off:


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A. the pump will burn up
B. it usually means the motor is overloaded
C. it will have to be replaced
D. the pump has an obstruction in it and must be turned over by hand till the obstruction is cleared
Design of the casing of centrifugal pump should be such as to minimize the______
A. back flow through impeller
B. loss of kinetic head
C. loss of static head
D. none of these
Propeller type centrifugal pumps are most suitable for______
A. high capacity at high heads
B. high capacity at low heads

C. Low capacity at high heads
D. low capacity at low heads
a pump is a machine used
Answer: to move liquid through a piping system and to raise the pressure of the liquid
A pump can be further defined as a machine that uses several energy transformations
Answer: to increase the pressure of a liquid
The energy input into the pump is typically ……………….. This is electricity used to power an electric motor.
Answer: the energy source used to power the driver
……………….. is the driving force responsible for the movement of the fluid.
Answer: Pressure
………………… is the force that slows down fluid particles.
Answer: Friction
………………… is the amount of volume that is displaced per unit time
Answer: Flow rate