单项选择题
A.Piston pump B.Screw pump C.Diffuser pump D.Water-ring pump
The pump discharge pressure will be considerably higher...
单项选择题The pump discharge pressure will be considerably higher than the pressure at the （）.
A.pump entry branch B.outlet pipe C.impeller D.None of the above is true
What is the purpose of a relief valve?（）A.to fill 2 tan...
单项选择题What is the purpose of a relief valve?（）
A.to fill 2 tanks at the same time B.to use pump at a higher pressure C.to return liquid to suction side if discharge valve is closed D.All of the above are true
A （） pump is that where the volume of the pump chamber ...
单项选择题A （） pump is that where the volume of the pump chamber is alternately increased to draw the liquid in and then decreased to force the liquid out.
A.injector B.positive displacement C.centrifugal D.centripetal
