Pump operations and Maintenance Flashcards
If a centrifugal pump losing its prime after starting may be caused by:
- Air leaks in the suction line or packing
- Too low of a suction head
- Entrained air in liquid
- Shaft misalignment
- Wrong rotation
A) 2, 3, 5 B) 2, 3, 4 C) 1, 2, 3 D) 1, 3 E) 1, 4, 5
C) 1, 2, 3
Two types of pump shaft misalignments are:
A) Axial and articulated B) Parallel and vertical C) Side and vertical D) Axial and angular E) Inner and outer
D) Axial and angular
A mechanical pump seal:
A) Is used in reciprocating pump service
B) Does not need cooling
C) Will have a substantial amount of leakage
D) Will cause more wear on the shaft than a packing seal
E) Is used for high pressure service
E) Is used for high pressure service
Mechanical seals:
- Are used where leakage is objectionable
- Replace stuffing boxes
- Provide a better seal than packing
- Are less costly than stuffing boxes
A) 2, 4 B) 2, 3 C) 1, 2, 3 D) 1, 2 E) 2, 3, 4
C) 1, 2, 3
A slight leakage is desired between the pump shaft and packing in the majority of pumps in order to:
A) Prevent the pump from vapour locking B) Prevent the ingress of air C) Increase pump capacity and efficiency D) Lubricate the surfaces E) Prevent wearing of the wear rings
D) Lubricate the surfaces
Mechanical seals:
A) Are less expensive than packing B) Require more maintenance than packing C) Eliminate shaft wear D) Can be run dry E) Use a lantern ring
C) Eliminate shaft wear
Compression type packing, used in pumps, is located in the:
A) Stuffing box B) Bearing pedestal C) Packing chamber D) Diffuser housing E) Impeller shroud
A) Stuffing box
Lantern rings:
- Prevent liquid leakage from the pump
- Are fed by a liquid
- Provide a seal to prevent air from entering the pump
- Prevent leakage between the impeller and casing
A) 1, 2 B) 2, 3, 4 C) 1, 2, 3 D) 2, 3 E) 3, 4
D) 2, 3
A stuffing box:
- Stops air leaking into the casing when the pressure is below atmospheric
- Decreases casing leakage when the pressure is above atmospheric
- Is always supplied with a lantern ring
- Is filled with packing
A) 2, 3 B) 2, 3, 4 C) 1, 2, 4 D) 1, 4 E) 1, 3
C) 1, 2, 4
If a centrifugal pump is located above the source of supply the suction line is equipped with a:
A) Suction globe valve B) Safety relief valve C) Priming connection D) Foot valve E) Wearing ring
D) Foot valve
If a stuffing box is to prevent the ingress of air, it is equipped with a/an:
A) A thrust collar B) A vacuum breaker C) A bushing D) A seal cage E) An anti air siphon
D) A seal cage
What size of packing would you use to repack a pump gland with a stuffing box bore of 8.6 cm and a pump shaft diameter of 6.7 cm?
A) 0.5 cm B) 0.675 cm C) 0.95 cm D) 1.9 cm E) 1.6 cm
C) 0.95 cm
The process of filling a pump and its suction line with liquid, prior to starting the pump, is known as:
A) Priming B) Aligning C) Wringing D) Distributing E) Brindling
A) Priming
Flexible couplings will compensate for:
A) Impeller imbalance B) Angular shaft misalignment C) Bearing failure D) Shaft eccentricity due to a badly bent shaft E) Overheating of packing
B) Angular shaft misalignment
Wear rings are usually constructed of:
A) Ceramics or aluminum B) Steel or alloy steel C) Wrought iron or pig iron D) Graphite or bronze E) Bronze or cast iron
E) Bronze or cast iron
