PHEP Ch 6

Question 1

Excessive vapors in the inlet or suction side of a liquid pump will cause the pump to

• Slow down
• reverse
• lose prime
• speed up

Answer 1

C: Lose Prime

Question 2

The most efficient type of impellar to use for conditions of small capacities and high heads would generally be the:

Answer 2

A: Radial

Question 3

Specific speed refers to or indicates

Answer 3

C: the speed a model of a given design would operate to discharge one gallon per minute against one foot head

Question 4

In a constant speed centrifugal pump any increase in flow rate beyond that for which the pump is designed to handle will normally cause

Answer 4

a drop in both efficiency and discharge pressure

Question 5

which one of the following conditions would normally act to increase the total pump head?Installation of new

• clearance or wearing rings
• replacing old discharge piping with new piping
• extending the length of discharge piping
• repairing cavitation areas in impellars

Answer 5

Installation of new clearance or wearing rings
replacing old discharge piping with new piping
extending the length of discharge piping
repairing cavitation areas in impellars

E: all of the above

Question 6

One foot of pump head is a static force exerted by a column of water one foot high on an area of one square inch. it is equal to how many pounds of pressure?

Answer 6

C: .434

Question 7

the head generated by the centrifugal pump is always expressed in?

Answer 7

C: feet of liquid

Question 8

in what part of a centrifugal pump is the kinetic energy in the fluid converted to potential or pressure energy?

Answer 8

B: the Casing

Question 9

the function of a latern ring in the stuffing box of a centrifugal pump is to?

Answer 9

A: Distribute sealing or lubricating water around the pump shaft

Question 10

The purpose of wearing or labyrinth rings in centrifugal pumps is to

• Control inter-stage losses
• reduce recirculation losses
• reduce maintenance costs

Answer 10

• Control inter-stage losses
• reduce recirculation losses
• reduce maintenance costs

D: all of the above

Question 11

inter-stage leakage in multi-stage centrifugal pumps is most usually controlled by the use of

• wearing rings
• mechanical seals
• packing
• All of the above

Answer 11

A: Wearing rings

Question 12

The laws governing the temperature pressure relations of the liquids explain why a force must be used to cause a liquid to flow into a pump and relate most nearly to

Answer 12

A: Net positive suction head

Question 13

the purpose of the volute type of casing or diffusion vanes of centrifugal pumps is to

Answer 13

C: reduce the velocity and increase the pressure of the discharging fluid

Question 14

what type of pump is best suited for the handling of dirty water

Answer 14

A: non positive displacement

Question 15

what type of pump operates on the velocity restriction principle

Answer 15

D: ejector

Question 16

what type of pump can be operated with the discharge valve closed

Answer 16

D: centrifugal

Question 17

check valves are sometimes installed in the suction line of pumps to

Answer 17

B: preventing suction loss or shutdown

Question 18

fluid density, height fluid must be raised, pipe friction, and static pressure all relate to

Answer 18

A: Total pump head

Question 19

the motion exerted by pumps on the fluids pumped may be due to

• reciprocating action
• centrifugal action
• jet action
• all of the above

Answer 19

• reciprocating action
• centrifugal action
• jet action

D: all of the above

Question 20

the work of pumping consists of discharging a quantity of liquid or gas against an?

Answer 20

C: resistance