Telescopic butterfly valve disc to install the pipe diameter direction. In the cylindrical channel of the valve body, disc-shaped disc around the axis of rotation, the rotation angle between 0 ° ~ 90 ° rotation to 90 ° when the valve is open all license conditions. This valve is generally horizontal mounting. The characteristics of the new high-life stainless steel butterfly valves and butterfly valves in the course of problems 
 Telescopic butterfly valve as a kind used to achieve piping system off and flow control components, has been in the petroleum, chemical, metallurgy, water, electricity and many other fields to be very widely used. Butterfly valve technology has been known in its sealed form of the use of the seal structure, the sealing material such as rubber, PTFE. Due to the limitations of structural features, not suited to high temperature, high pressure and corrosion resistance, abrasion resistance, and other industries. A more advanced existing butterfly valve is a triple eccentric metal hard seal butterfly valve and valve seat the Siamese components, the seat sealing surface layer welding temperature, corrosion resistant alloy material. Multi-layer soft stacked seals in the valve plate, this butterfly with the traditional butterfly valve compared with the high temperature, easy operation, open and close without friction, is turned off with the increase of transmission of the torque to compensate for seal and improve the butterfly valve sealing performance 
 Telescopic butterfly valve still exists in the course of the following questions: 
 , Due to the soft and hard stacked ring fixed in the valve plate when the valve plate is normally open state media sealing surface to form a positive erosion subject to erosion, soft seal with the sheet metal sandwich, direct impact on seal performance. 
 Second, the structural conditions limit the structure do not meet the following diameter DN200 valve, because the overall structure of the valve plate is too thick, the flow resistance. 
 Third, due to the principle of eccentric structure, the sealing surface of the valve plate and valve seat seal on the transmission of torque to the valve plate pressure to the valve seat. Positive flow state, the higher the pressure medium sealed tight squeeze. Countercurrent flow medium with the media pressure between the valve plate and seat unit is pressure less than medium pressure seal started to leak. 
 High-performance soft sealing butterfly valve, characterized in that: said valve seat ring by the soft T-shaped seal ring on both sides of multi-layer stainless steel sheet. The valve plate and valve seat sealing surface of the oblique cone structure of the welding temperature of the surface of the valve plate oblique cone, corrosion resistant alloy material; fixed to the structure of the adjustment bolt assembly on the spring plate adjustment between the ring plate. This structure effectively compensate for the elastic deformation of the sleeve and the valve between the tolerance zone and the stem in the media pressure to solve the sealing problem of the valves in the two-way transmission medium of exchange process. T-soft on both sides of multi-layer stainless steel sheet to form a ring, has the dual advantages of a metal seal and soft seal with zero leakage sealing performance, both in the case of low and high temperature. The test proved positive Chi flow state (medium flow direction and the rotation of the disc in the same direction), the sealing surface pressure torque transmission device and media pressure on the valve plate to produce. Positive media pressure increases when the valve plate oblique cone surface with the valve seat sealing surface tight squeeze, sealing the better. When the counter-current state, the seal between the valve plate and valve seat by the drive torque to the valve plate to the seat. Reverse media pressure between the valve plate and seat unit is pressure to less than medium pressure spring adjustment ring deformation under load, store, compensation for the valve plate and valve seat sealing surface of the tight The pressure to play the role of automatic compensation. Therefore, the present invention, unlike existing technologies, as in the valve plate to install the software and hardware multi ring, but directly installed on the body, an additional plate and the middle seat adjustment ring is the ideal way hard sealing . It will replace the gate valve, ball valve durability advantages telescopic butterfly valve performance several categories 

 1, classification by structure 

 (1) center sealing butterfly valve 

 (2) a single eccentric sealed coal valve 

 (3) double eccentric sealing butterfly valve 

 (4) three eccentric seal stamped valve