Reciprocating pump:
The reciprocating pump is a pump that uses the reciprocating motion of the piston to deliver liquid. The reciprocating motion of the piston transfers energy directly to the liquid in the form of static pressure energy. Since the liquid is incompressible, when the piston pressurizes the liquid, the liquid can be subjected to a high pressure, thereby obtaining a high head.
Rotor pump:
The rotor pump consists of a stationary pump casing and a rotating rotor. It has no suction valve and discharge valve. The side of the pump body where the rotor contacts the liquid directly acts on the liquid in the form of static pressure, and is squeezed by the rotating rotor The function discharges the liquid, while leaving a space on the other side, forming a low pressure, so that the liquid is continuously sucked. The head of the rotor pump is high, the flow rate is usually small, and the discharge is uniform. It is suitable for conveying liquids with high viscosity and lubricity, but without solid particles. Types include gear pumps, screw pumps, sliding vane pumps, flexible impeller pumps, roots pumps, rotary piston pumps, etc., of which gear pumps and screw pumps are the most common rotor pumps.
The screw pump is a type of rotor pump, which has the following advantages compared to reciprocating pumps: (1) It has the stability of centrifugal pump operation, no noise (only the sound of the motor is heard), no oil leakage, and no dirty oil recovery device And water cooling and other auxiliary equipment; (2) It has the characteristics of high efficiency of the volumetric pump, and the displacement is constant (fixed speed) when the pressure changes; (3) There are few leakage points, small maintenance, low maintenance cost, and short maintenance time. However, the screw pump is mainly used to transport high-viscosity oil products. The efficiency of transporting thin oil is relatively low, and the outlet pressure cannot be too high, otherwise the internal leakage will increase and affect the safe use of the pump. At the same time, the screw pump is poorly adapted to changes in flow rate. Pipes with large flow changes require additional equipment such as frequency converters to adjust the pump flow.
