The centerline butterfly valve has a simple structure and easy to manufacture, but due to its structure and material limitations, the application conditions are limited. In order to meet the requirements of actual application conditions, continuous improvements have been made on this basis, and then single eccentric butterfly valves, double eccentric butterfly valves, and triple eccentric butterfly valves have appeared. The biggest feature of this third eccentricity is that it fundamentally changes the sealing structure. It is no longer a positional seal, but a torsion seal, that is, it does not rely on the elastic deformation of the valve seat, but completely depends on the contact surface pressure of the valve seat. The sealing effect, therefore, solves the problem of zero leakage of the metal valve seat in one fell swoop, and because the contact surface pressure is proportional to the medium pressure, the high pressure and high temperature resistance is also easily solved.

Advantages of triple eccentric design

  1. The unique conical seal design ensures that the disc does not touch the sealing surface until the valve is closed-this leads to a repeatable seal and greatly extends the service life of the valve.

  2. The shape of the valve plate of the triple eccentric butterfly valve is an elliptical cone, and its surface is welded with hard alloy, which has excellent wear resistance. The floating U-shaped stainless steel seat has the function of automatically adjusting the center. When the valve is opened, the elliptical cone sealing surface valve disc is first separated from the U-shaped elastic valve seat, and then rotates; when closed, the valve disc rotates, and the valve disc automatically adjusts the center to the elastic valve seat under the action of the eccentric shaft. The seat applies pressure to deform the valve seat until the valve seat and the elliptical conical sealing surface of the valve disc closely match. When the valve is opened and closed, the butterfly disc 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, thereby eliminating the common jumping phenomenon when opening the valve.

  3. Metal-to-metal sealing ensures that the air bubbles are closed tightly to achieve zero leakage performance

  4. Suitable for harsh media-the all-metal structure provides corrosion and heat resistance that other butterfly valve designs with elastic seals do not have

  5. The geometric design of the sealing components can provide frictionless travel throughout the valve. This prolongs the life of the valve and allows the installation of lower torque actuators.

  6. There is no cavity between the sealing components, which will not cause blockage, reduce maintenance costs and extend valve life.

  7. Valve seat design can prevent the valve from overstroking