The high temperature ball valve is a metal seal structure, the sealing form is metal to metal seal, metal seal ring can be changed to metal seal, stainless steel plate and graphite composite plate seal ring are metal sealed. The driving form of the hard seal butterfly valve is manual, worm drive, pneumatic and so on, besides electric power. The butterfly plate of a high temperature ball valve is installed in the direction of the diameter of the pipe. In the cylindrical channel of the hard sealing ball valve body, the disc shaped butterfly plate revolves around the axis, the rotation angle is 0 degrees ~90 degrees, when the rotation is 90 degrees, the valve is fully opened.
At present, corrosion resistant ball valve and hard seal butterfly valve are widely used in many fields, such as petroleum, chemical industry, metallurgy, hydropower and so on, as a part of pipeline system's on-off and flow control. In the known butterfly valve technology, the sealing structure is mostly sealed, the sealing material is rubber, polytetrafluoroethylene and so on. Because of the limitation of structural features, it is not suitable for high temperature, high pressure, corrosion resistance and wear resistance industries. A more advanced butterfly valve is a three eccentric metal hard seal butterfly valve. The valve body and valve seat are joined components, and the valve seat sealing surface layer is overlaid with temperature and corrosion resistant alloy materials. Multilayer soft stacked ring fixed in the valve plate, this butterfly valve compared with the conventional high temperature, easy operation, open and close without friction, closed with the transmission of the torque increases to compensate for seal, to improve a butterfly valve sealing performance and durability advantages.