单项选择题
A.non-pulsating B.pulsating C.positive D.non-positive
The emergency bilge suction or bilge （） is used to prev...
单项选择题The emergency bilge suction or bilge （） is used to prevent flooding of the ship.
A.injection valve B.relief valve C.discharge valve D.inlet filter
In （） pump a closed discharge valve will not cause exce...
单项选择题In （） pump a closed discharge valve will not cause excessive pressure to build up.
A.gear B.vane C.screw D.centrifugal
Centrifugal pumps are non-positive and a fairly （） unit...
单项选择题Centrifugal pumps are non-positive and a fairly （） unit.
A.low pressure B.low discharge C.low speed D.high pressure
