To prevent the working fluid from the pump leak out or prevent outside intrusion into the pump or air impurities inside the device or measures as sealing, sealed medium is generally liquid, gas or dust.

　　Leakage caused by two main reasons: First, seal the surface of a gap. Second, the difference pressure on both sides of sealing parts, eliminate or reduce any of these factors can prevent or reduce leakage to achieve the purpose of sealing. Pump design pressure and operating pressure is an objective reality can not be reduced, so the pump seal is the solution to eliminate or reduce the gap between the sealing surface. This space includes the space between the sealing surface and seals the internal clearances Bunsen.

　　Pump seal including two categories: static seal and dynamic seal. Static sealing gaskets are usually sealed, O-ring seal, thread sealing type. Dynamic seal are mainly soft packing seals, oil seals, labyrinth seals, screw seal, dynamic seals and mechanical seals.