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Three eccentric butterfly valve belongs to rotary valve. The third eccentricity is placed on the valve plate. In the process of valve manufacturing, the outer edge of valve plate adopts part of outer spherical structure. The surface roughness of the outer eccentric spherical surface is Ra0.4 after polishing, and the spherical surface is plated with chromium or overlaid with stellite alloy. The hardness is hrc45 ~ 60. The maximum pressure resistance of the three eccentric disc valve is 26 MPa, the temperature resistance is as low as - 196 ℃ and as high as 700 ℃, and the sealing reaches zero leakage. It can be seen that it is due to the innovative structural characteristics of triple eccentric butterfly valve that it has the following main characteristics.

(1) set regulation and cut-off in one, strong controllability.

The new type of triple eccentric butterfly valve adopts double safety structure. In order to prevent deformation of butterfly plate, dislocation of valve stem and occlusion of sealing surface caused by the influence of fluid pressure and temperature, two independent thrust rings are installed on the upper and lower sides of butterfly plate to ensure the normal operation of valve under any working conditions; in order to prevent sudden accidents caused by damage and flying out of valve stem, the valve is equipped with two independent thrust rings, At the lower end of the valve, the internal and external parts of the valve stem are designed with independent valve stem flying out prevention mechanism.

(2) no dead zone design, small opening torque.

The valve plate shape of triple eccentric butterfly valve is oval cone, and its surface is overlaid with cemented carbide. The floating U-type stainless steel seat has the function of automatic center adjustment. When the valve is opened, the valve plate with oval cone sealing surface first breaks away from the U-shaped elastic seat. Then rotate again; when closing, the valve plate rotates. Under the action of the eccentric shaft, the valve plate automatically adjusts the center to the elastic seat, and pressurizes the valve seat to deform the valve seat until the valve seat and the elliptical conical sealing surface of the valve plate are closely matched. When the valve is opened and closed, the butterfly plate does not scratch the valve seat, and the torque of the valve stem is directly transmitted to the sealing surface through the butterfly plate, and the opening torque is small, thus eliminating the common jumping phenomenon when opening the valve, that is, eliminating the dead zone (no band). The non dead zone design enables the triple eccentric butterfly valve to enter the adjustable area from 0 to 90. The maximum regulation ratio can be as high as 100:1, which is twice as high as that of ordinary butterfly valve.

(3) zero leakage, high temperature and high pressure resistance.

The biggest characteristic of three eccentricities is that it fundamentally changes the sealing structure, which is not position sealing, but torque sealing. That is, it does not rely on the elastic deformation of the valve seat, but completely relies on the contact surface pressure of the valve seat to achieve the sealing effect. This sealing structure enables the triple eccentric butterfly valve to achieve hard sealing class VI and achieve true zero leakage. At the same time, due to the selection of metal seat and the structural characteristics of face seal, the problem of high temperature and high pressure resistance is solved.

In addition, the triple eccentric butterfly valve adopts the body seat structure. It makes the valve structure more compact, reduces the chance of the valve seat directly contacting with the medium, reduces the erosion degree of the valve seat, and effectively prevents the influence of the small solid in the medium and the sealing surface occluding caused by thermal expansion, thus prolonging the service life of the valve seat.http://www.didlink-valve.com/

The valve seat of the new type three eccentric butterfly valve can be replaced, and the sealing surface of the butterfly plate is independent of the butterfly plate. The sealing surface of the butterfly plate can also be replaced, which greatly reduces the maintenance cost.