This pump substitutes static seal for dynamic seal avoids medium leakage. Pump casing is mainly made of RPP. And it is a new product adopted excellent hydraulic model. The product has good corrosion-resistance, no leakage. It can be used to deliver liquid excluding iron tramp and hard solid particle whose viscosity is not more than 30cst. Especially it can deliver virulent, flammable, explosive, corrosive or other high-purity liquid too.