Eccentric Butterfly Valve

1.Concentric Butterfly Valve

Feature: the axis of the shaft, the center of the disc, and the center of the body are in a line.

This structure is simple and is easy to be manufactured. However, the disc and seat are always in a state of compression and scratching, resulting in a large resistance distance and fast wear.

2.Single-offset Butterfly Valve

To solve the problem of compression between the disc and the seat of the concentric butterfly valve, a single eccentric butterfly valve has been developed, which is characterized by the deviation of the shaft axis from the center of the disc, so that the upper and lower ends of the disc no longer become the axis of rotation, dispersing and reducing the excessive compression between the upper and lower ends of the disc and the seat. However, due to the fact that the single eccentric structure does not eliminate the scratch between the disc and the seat during the entire opening and closing process of the valve, and is similar in application field to concentric butterfly valves, it is not widely used.

3.Double-offset Butterfly Valve

Feature: the shaft axis is offset from the body center line and the disc center line.

It is further improved based on the single-offset butterfly valve. This design enables the disc to quickly detach from the seat after the valve is opened, greatly eliminating unnecessary excessive compression and scratching between the disc and the seat, reducing wear and improving the service life of the seat. The significant reduction in scratching and the use of metal seats in double eccentric butterfly valves have improved their application in high-temperature fields.

4.Triple-offset Butterfly Valve

Feature: the shaft axis is offset from the body center line and the disc center line; the conical axis of the disc sealing surface is deviated from the cylindrical axis of the body.

Metal-to-Metal Sealing: The valve uses a metal-to-metal sealing mechanism, typically with a laminated stainless steel or graphite seal ring. This type of sealing provides excellent resistance to high temperatures, pressures, and corrosive media.

Bi-Directional Sealing: The triple-offset butterfly valve can provide a bi-directional sealing capability, allowing it to be installed in either flow direction. This flexibility is particularly useful in applications where the flow direction may change.

Low Torque Operation: The design of the valve reduces the operating torque required to open and close the valve. This feature makes it easier to operate the valve, especially in larger sizes or high-pressure applications.