Features of triple eccentric butterfly valve

The traditional hard-sealing butterfly valve has no guarantee of sealing performance and may have a large leakage. In order to improve this situation, the hard-sealing butterfly valve has been reformed many times, and the triple offset butterfly valve has been born. 

What is Triple offset butterfly ？

The axial center of the valve stem is simultaneously deviated from the center of the disc and the center of the body, and the rotation axis of the valve seat has a certain angle with the axis of the valve body passage, which is called a triple offset butterfly valve.

What are three eccentricities of triple offset butterfly valve?

The first eccentricity is that the valve shaft is located behind the valve plate shaft, allowing the seal to fully surround the entire seat.

The second eccentricity is that the center line of the valve shaft deviates from the center line of the pipeline and the valve to avoid the interference of the opening and closing of the valve.

The third eccentricity is that the cone axis of the seat deviates from the centerline of the spindle. In this way, friction can be eliminated in the process of closing and opening, and uniform compression sealing effect around the whole valve seat can be achieved.

What is the feature of triple offset butterfly valve?

Tri-eccentric butterfly valve is widely used in metallurgical, electric power, petrochemical, water supply and drainage, municipal construction and other industrial pipelines with medium temperature ≤425℃. Material is divided into: cast iron, cast steel, stainless steel, its main features are:

The biggest feature of this third eccentricity is that it fundamentally changes the sealing structure, 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 relies on the contact surface pressure of the valve seat to achieve the seal. The effect solves the problem of zero leakage of the metal valve seat in one fell swoop, and the contact surface pressure is proportional to the medium pressure, and the high pressure and high temperature are also solved.

Since its inception, the three-offset disc valve has undergone a process of self-improvement and continuous development in order to meet the increasingly severe working conditions. Even the most basic zero leakage, theoretically three offset disc valves can be achieved, but in fact depends on careful design and precision manufacturing.