Application of high performance three eccentric two way hard sealing butterfly valve

                  Column:Technical article Time:2017-11-24
                  At present, the butterfly valve, as a component to realize the on-off and flow control of the pipeline system, has been widely used in many fields, such as petroleum, chemical industry, metallurgy, hydropower and so ...

                  At present, the butterfly valve, as a component to realize the on-off and flow control of the pipeline system, has been widely used in many fields, such as petroleum, chemical industry, metallurgy, hydropower and so on. In the known butterfly valve technology, the sealing form is mostly sealed structure, the sealing material is rubber, PTFE and so on. Due to the limitation of structural characteristics, it is not suitable for high temperature, high pressure and corrosion resistance, abrasion resistance and other industries. A more advanced butterfly valve is three eccentric metal hard seal butterfly valve, valve body and seat are conjoined components, valve seat sealing surface layer surfacing temperature resistance, corrosion resistant alloy material. 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. However, the butterfly valve in the use of the process still exist the following problems:


                  When the valve plate is normally open, the medium forms a positive erosion on its sealing face, and the soft seal in the metal sandwich layer is directly affected the sealing performance after being washed.


                  Two, limited by the structural conditions, the structure can not adapt to the diameter of DN200 below the valve, because the valve plate structure is too thick, large flow resistance.


                  Three, because of the principle of three eccentric structure, the sealing between the valve plate and the valve seat is driven by the torque of the drive plate to the valve seat. In the positive flow state, the higher the medium pressure, the tighter the sealing extrusion. When the flow medium counter flow, with the increase of medium pressure, the unit pressure between the valve plate and the valve seat is less than the pressure of the medium, the seal begins to leak.


                  The purpose of the utility model is to provide a high performance three eccentric two way hard sealing butterfly valve with zero leakage, flexible opening and closing, long service life, high temperature resistance, high pressure, corrosion resistance, abrasion resistance and wide application range.


                  The high performance three eccentric two way hard seal butterfly valve is characterized in that the seat seal ring is composed of multi-layer stainless steel sheets on both sides of the soft T seal ring. The sealing surface of the valve plate and the valve seat is an oblique cone structure, and the heat-resistant and corrosion-resistant alloy material is deposited on the inclined cone surface of the valve plate; the structure of the adjusting bolt assembled between the spring fixed on the adjusting ring plate and the pressing plate is assembled. This structure effectively compensates the tolerance between the sleeve and the valve body and the elastic deformation of the valve stem under the medium pressure, and solves the sealing problem existing in the process of bidirectional exchange of the medium in the valve.


                  The sealing ring made of soft T type multi layer stainless steel sheet has the dual advantages of metal hard seal and soft seal. It has zero leakage sealing performance both in low temperature and high temperature.


                  The test proves that the pressure of the sealing face is the effect of the torque of the transmission device and the medium pressure on the valve plate when the positive flow state of the tank is the same as the direction of the flow direction of the butterfly plate. When the positive medium pressure increases, the inclined cone surface of the valve plate and the sealing surface of the valve seat are squeezed more tightly, and the sealing effect is better.


                  When the counter flow state, the seal between the valve plate and the valve seat depends on the torque of the driving device to press the valve plate to the valve seat. With the increase of the reverse medium pressure, the unit positive pressure between the valve plate and the valve seat is less than the pressure of the medium, and the spring stored in the regulating ring can compensate the tight pressure of the valve plate and the sealing surface of the valve seat automatically after the load is stored. Therefore, the utility model does not install the soft and hard multi-layer sealing ring on the valve plate as the existing technology, but is directly installed on the valve body, and an adjusting ring is arranged between the pressing plate and the valve seat, which is an ideal bidirectional hard sealing mode. It can replace gate valve, globe valve and globe valve.

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