PUMPS AND EDUCTORS
1.How is water traveling along the shaft of a centrifugal pump prevented from entering the shaft bearing?
2.Which of the listed types of pumps is NOT likely to be installed in a main drainage or evacuation system?
C.High pitch rotary vane pump
3.Why are removable sleeves installed on centrifugal pump shafts?
A.They make it easier to replace the pump shaft packing.
B.They can be economically replaced as they wear out.
C.They can be removed when it is necessary to lighten the weight of the pump.
D.They increase the strength of the shaft.
4.A boiler forced draft pressure gage indicates 15 cms of water. This corresponds to a pressure of ____________.
A.150 mm WG
5.An inadequate reciprocating bilge pump discharge is most often caused by ___________.
A.Loss of suction
C.scarred cylinder walls
D.clogged drain valves
6.Increasing the speed of a rotary pump above its rated speed will result in which of the following conditions to occur?A.defective intake valves
B.clogged suction strainers
7.Propeller pumps are used primarily where there is a need to move a large volume of liquid. However, their use is limited by a maximum total head of ____________.
A.6 to 12 metres
B.10 to 17 metres
C.12 to 20 metres
D.17 to 24 metres
8.If a centrifugal pump is driven by a constant speed electric motor and produces a discharge pressure less than designed, the cause is probably _______________.
A.excessive pump speed
B.excessive suction head
C.worn wearing rings
D.gross pump misalignment
9.Which features of a centrifugal pump reduce the need for renewing worn impellers and pump casings?
A.Close radial clearance between impeller hub and casing
B.Low rotational speed of impeller
C.Removable end plate
D.Replaceable impeller and casing wearing rings
10.A centrifugal pump may fail to deliver water when first started if the _________.
A.water seal pipe is plugged
B.pump is not primed
C.seal ring is improperly located
D.impeller is flooded