Chapter 23 Pump Operation & Maintenance

Question 1

Wear rings for a centrifugal pump can be installed on the:

a) Stuffing box
b) Pump shaft
c) Pump casing or shaft or both
d) Impeller or casing or both

Answer 1

d) Impeller or casing or both

Question 2

Packing in the stuffing box of a centrifugal pump:

a) Should not stop leakage entirely
b) Consists of ceramic and graphite components
c) Requires no lubrication
d) Should stop leakage entirely

Answer 2

a) Should not stop leakage entirely

Question 3

A centrifugal pump that has high suction lift and a resulting negative casing pressure will likely have:

a) Wear rings installed
b) A lantern ring or seal cage in the stuffing box
c) No leakage from a lantern equipped stuffing box
d) No need for a shaft sleeve

Answer 3

b) A lantern ring or seal cage in the stuffing box

Question 4

Priming of a centrifugal pump means:

a) Filling the casing with the fluid being pumped
b) Evacuating the casing of air
c) Filling the casing and suction line with the fluid being pumped
d) Installing a foot valve on the pump discharge line

Answer 4

c) Filling the casing and suction line with the fluid being pumped

Question 5

Wear rings are usually constructed of:

a) Ceramics or aluminium
b) Graphite or bronze
c) Bronze or cast iron
d) Steel or alloy steel

Answer 5

c) Bronze or cast iron

Question 6

Flexible couplings will compensate for:

a) Overheating of packing
b) Axial shaft misalignment
c) Shaft eccentricity due to a badly bent shaft
d) Impeller imbalance

Answer 6

b) Axial shaft misalignment

Question 7

Most pump failures and/or damage occurs:

a) After about 6 months of continuous service
b) Due to vapour-binding
c) During initial start-up
d) Because of inadequate operator training

Answer 7

c) During initial start-up