单项选择题
A.circular B.elliptical C.rectangular D.hexagon
Throttling in the （） line of a centrifugal pump involve...
单项选择题Throttling in the （） line of a centrifugal pump involves the risk of the pump cavitation.
A.suction B.exhaust C.pressure D.discharge
A positive displacement pump is that where the volume o...
单项选择题A positive displacement pump is that where the volume of the pump chamber is alternately increased to （） and then decreased to （）.
A.draw the liquid in；force the liquid out B.force the liquid out；draw the liquid in C.suction；draw D.deliver；outlet
The amount of fluid delivered by a helical pump can be ...
单项选择题The amount of fluid delivered by a helical pump can be regulated by （）.
A.throttling the pressure line B.changing the speed of the rotor C.either A or B D.None of the above is tree
