At present, the butterfly as a piping system used to implement off and flow control components, has been in the petroleum, chemical industry, metallurgy, water, electricity and many areas are very widely used. In the butterfly valve has been publicly known technology, glue stick the seal forms a sealed structure, sealing material for rubber, PTFE and so on.
As the structural characteristics of the restriction is not suitable for high temperature, high pressure and corrosion resistance, abrasion resistance and other industries.
Present a more sophisticated three eccentric butterfly valve is metal seal butterfly valve, valve and seat components for the piece, the valve seat sealing surface layer welding temperature,glue gun corrosion resistant alloy material. Multi-layer soft-stacked ring fixed in the valve plate, this butterfly valve in comparison 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.
However, this butterfly is still in the course of the following problems:
First, the soft and hard stacked ring fixed in the valve plate, when the valve plate normally open state media, the formation of the front sealing surface erosion, and metal sheets laminated in the soft seal by brushing with a direct impact on seal performance.
Second, by the structural constraints of the structure do not meet the following valves DN200 diameter, because the overall structure of thick disc, large flow resistance.
Third, because the principle of three eccentric structure, the valve plate sealing surface and the seal between the valve seat is on the transmission of torque to the valve plate to the seat. Positive flow state, the higher the pressure medium sealed tight squeeze. When the flow upstream medium with medium pressure valve plate and seat the pressure between the units is less than the medium pressure, the seal began to leak.
High-performance three-eccentric hard sealing butterfly valve, characterized in that: as described in T-shaped valve seat ring seal ring by the soft layers on both sides of stainless steel sheet. Valve plate and seat sealing surface for the oblique cone structure, oblique cone surface in the valve plate welding temperature, corrosion resistant alloy materials; fixed in the regulation of the spring between the ring plate and the plate with the adjusting screw assembly structure.
This structure effectively compensate for tolerances between the sleeve and the valve stem in the medium zone and the elastic deformation under pressure to solve the two-way valve in the transmission medium of exchange exist in the process of sealing problems. On both sides by T-soft stainless steel sheet composed of multi-ring, with a metal seal and soft seal the dual advantages of both low and high temperature conditions, both with zero leakage sealing performance.
Test proved positive Chi flow state (flow direction of medium and disc rotation in the same direction), the sealing surface pressure is the transmission of torque and media pressure on the valve plate efficacy. Positive medium pressure valve plate oblique cone surface and the valve seat sealing surface squeezed more tightly, sealing the better. When the counter state, the valve plate and seat the seal between the drive torque to the valve plate to the seat. With the reverse media pressure, the valve plate and seat the pressure between the units is less than the medium pressure, the adjustment ring in the spring under load to compensate for the deformation stored in the valve plate and valve seat sealing surface of the tight pressure to play the role of automatic compensation. Therefore, this utility model, unlike existing technologies, as the valve plate to install software and hardware multi ring, but directly installed on the body, the middle seat in the platen and an additional adjustment ring is a very good way of two-way seal . It can replace the gate valve and ball valve.