At present, butterfly valve, as a kind of components used to realize the pipe system breaking and flow control, has been widely used in many fields, such as oil, chemical, metallurgy, hydropower and so on. In the known butterfly valve technology, its sealing form mostly adopts the sealing structure, and the sealing material is rubber, polytetrafluoroethylene and so on. Due to the limitation of structural characteristics, it is not suitable for such industries as high temperature, high pressure, corrosion resistance and wear resistance.

A more advanced butterfly valve is three eccentric metal hard seal butterfly valve, the valve body and the seat are connected components, and the sealing surface layer of the seat is surfacing with temperature resistant and corrosion resistant alloy materials. The multi layer soft superimposed seal is fixed on the valve plate. This butterfly valve has the high temperature resistance compared with the traditional butterfly valve, the operation is light and open and closed without friction. The valve is compensated and sealed with the torque of the transmission mechanism in the closed, and improves the sealing performance of the butterfly valve and the advantages of prolonging the service life. Because the multilayer soft and hard laminated seal is fixed on the valve plate, when the valve plate is often open, the medium has a positive scour to its dense cover, and the soft sealing belt in the interlayer of the metal sheet is scoured, which directly affects the sealing performance.