Mechanical seal is also named as end surface seal, a pair of perpendicular to its axis of rotation of the face, the face in the fluid pressure and external elastic compensation under the action of mechanical, sealed with the aid dependent, and the other end to keep fit, and sliding, thereby preventing fluid leakage.

　　1. Common periodic leakage

　　The sealing surface of dry friction caused by insufficient lubrication or nap Seals

　　Periodic vibration of the rotor, because the stator and the upper and lower or did not cover the impeller and shaft unbalance, cavitation or bearing damage

　　2. The medium caused by the leakage

　　Medium particles, impurities into the sealing surface caused by seal failure; dynamic and static secondary seal ring loss of proper function due to the weak acid medium, weak base erosion.

　　3. The pressure generated by leakage

　　High-pressure and pressure waves caused by the mechanical seal leakage

　　As the spring pressure than the design pressure and is better than too large, sealed chamber when the pressure exceeds 3Mpa, will seal face pressure ratio is too large, difficult to form the film, seal face serious wear and tear, heat increased, resulting in thermal deformation of the sealing surface.

　　Run the vacuum caused by the mechanical seal leakage

　　Pump starting and stopping process, due to the pump inlet clogging, pumping medium containing gas and other reasons, there may appear negative pressure sealed chamber, thereby causing the sealing surface of dry friction.

　　4. other problems caused by the mechanical seal leakage

　　Mechanical seal design exists, selection, installation and other unreasonable