Types of pumps

Question 1

Which of the following types of pumps require internal valves (that is, valves which are part of the pump)?

A) Rotary lobe
B) Rotary gear
C) Reciprocating
D) Centrifugal
E) Sliding vane

Answer 1

C) Reciprocating

Question 2

A rotary pump:

1. Is a variety of dynamic unit
2. Does not have discharge pulsations
3. Should be equipped with a relief valve
4. Has the highest capacity of any pump
5. Never requires casing lubrication

A) 3, 5
B) 1, 3
C) 2, 3
D) 1, 2
E) 3, 4

Answer 2

C) 2, 3

Question 3

The vertical distance from the liquid surface up to the pump center-line plus the vertical distance from the pump center-line up to the surface of the liquid in the discharge tank is:

A) Suction lift
B) Total static head
C) Static suction head
D) Static discharge head
E) Total discharge head

Answer 3

B) Total static head

Question 4

Rotary pumps:

1. Have tight clearances on all moving parts
2. Are normally used for boiler feed pumps
3. Are positive displacement units
4. Should not be started with discharge closed

A) 1, 2, 3
B) 1
C) 1, 2
D) 2, 3
E) 1, 3, 4

Answer 4

E) 1, 3, 4

Question 5

Liquid in a centrifugal pump leaves the impeller and enters the:

A) Baffle chamber
B) Vibration housing
C) Suction line
D) Volute casing
E) Pump seal

Answer 5

D) Volute casing

Question 6

Centrifugal pumps do not develop good suction lift because:

A) Their internal component clearances are too high
B) They favour pressure rather than volume
C) Atmospheric pressure is usually too low
D) The speed is too low
E) The pumped medium relative density is too high

Answer 6

A) Their internal component clearances are too high

Question 7

Pumps handling cryogenic materials operate:

A) As staged units
B) At extremely low temperatures
C) Nearly always as dynamic units
D) As tandem units
E) As high speed units

Answer 7

B) At extremely low temperatures

Question 8

The general construction of a centrifugal pump consists of:

A) An impeller surrounded by a casing
B) Gears rotating in a housing
C) A pulsating disc
D) A piston moving back and forth in a cylinder
E) Sliding vanes

Answer 8

A) An impeller surrounded by a casing

Question 9

A volute type of pump:

A) Is a positive displacement pump
B) Is more costly than diffuser pumps
C) Casing has an increasing cross-sectional area
D) Reduces the velocity in the discharge nozzle
E) Is a regenerative type pump

Answer 9

C) Casing has an increasing cross-sectional area

Question 10

The purpose of stationary diffuser vanes in a centrifugal pump is to:

A) Create smooth transition to the pump discharge
B) Increase the velocity of flow
C) Convert velocity to pressure
D) Reverse rotation of the fluid
E) Increase resistance to flow

Answer 10

C) Convert velocity to pressure