Screw pump is widely used in chemical industry, pharmaceutical, brewing, paper, food, and other units. It can transport contains particles with high concentration and viscosity < 10000 PaS and suspended slurry. Its transmission fluid flow is stable, no over flow, pulse and stirring shear grout phenomenon. Discharge pressure is nothing to do with speed, low flow can also keep the high excretion pressure. Flow speed is direct proportion with variable speed. Through speed exchanger institutions or high-speed motor can realize flow adjusting. Self-priming ability is high; the liquid flow direction is changed by the pump rotation, applicable for occasion of positive flush. It has the advantages of smooth operation, and vibration, low noise.