Positive displacement pump is to rely on working elements in the pump cylinder for reciprocating or rotary motion, so that work volume alternately increase and decrease, in order to achieve liquid inhalation and discharge. The reciprocating motion of the working elements of the positive displacement pump called the reciprocating pump, known as rotary motion rotary pump. The former suction and discharge process alternately in the same pump cylinder, and by the suction valve and the discharge valve to control; the latter is through the gear, screw, leaf rotor or slide and other working elements of the rotation, forcing the liquid from inhalation Side to the discharge side. Volumetric pump at a certain speed or reciprocating frequency of the flow is certain, almost no change with the pressure; reciprocating pump flow and pressure pulsation, the need to take appropriate measures to reduce pulsation; rotary pump generally no pulsation or only a small Pulsation; with self-suction capacity, the pump can be started immediately after the suction of liquid in the suction pipe; start the pump must be completely open the discharge pipe valve; reciprocating pump for high pressure and low flow; rotary pump for small and medium-sized flow And higher pressure; reciprocating pump suitable for conveying clean liquid or gas-liquid mixture.
