Screw pump is a kind of rotarypump, when the outlet end is blocked, the pressure will gradually increase, so that more than a predetermined pressure value.
螺杆泵是一种容积式回转泵，当出口端受阻以后，压力会逐渐升高，以至于超过预定的压力值。
2
The rotary motion of a profiled impeller in combination with a shaped pump housing or volute applies centrifugal force to discharge fluids from the pump.
成型叶轮的旋转运动以及成型的泵壳或蜗壳产生离心力从泵中排出流体。
3
Rotary piston pump is a volume type vacuum pump and is applied widely, but there has been no method for exactly calculating dynamic balance of rotary piston up to the present.