SPF series three-screw pump is self-priming three-screw pump. The surface-treated screw is covered with replaceable bushing. The starting screw is a hydraulic balance and the axial force of the working screw is absorbed by the bottom of the pump. Movement is also hydraulic. The helical surface almost does not transmit the torque generated by liquid friction, so the helical surface is not worn. All sliding parts are lubricated by medium. Shaft seal is mechanical seal, no leakage and no maintenance. The sealing chamber and the suction chamber are connected by an internal loop. The output pressure on the shaft seal is independent and only produces absorption pressure. Pump and motor are connected by bracket. When the spiral rotates, the three spirals of the seal chamber are axially complete Continuous movement The rotation of the spiral does not cause vibration. Outside the extrusion, the capacity of the seal chamber remains unchanged. The stability of structure design and operation ensures low noise and no pulsation of screw pump operation.