Eccentric Half Ball Valve

Structural features

One of the eccentric semi-ball valve features is no friction at open-close. Because of the eccentric structure, the ball gradually goes closed to the seat ring, during the valve close, till getting completely contacted at the closed position and, during valve open, the ball leaves the sealed position, e.g. completely comes away, a small opening torque. The second feature is that the sealing face can carry out self-cleaning. When the ball comes away from the seat ring, the medium may rinse out the accumulated objects on the face and, for easily crystallized medium, the ball,  during valve close, can cut off the crystal and get to the purpose of sealing, avoiding the problem with other valves unable to be opened and closed. The third one comes as tight sealing. Both ball and seat ring are bi-metal and, by means of different technologies, the sealing face can be combined into corrosion-proof, wearable etc. various types to meet with different working conditions. The sealing is formed by the contact of the sphere connecting line and zero-leak is made realized by the two-dimensional eccentric.

Principle of work

When the eccentric semi-ball valve is driven by the stem to move around the rotary center the oriting of the ball is a cam-like eccentric and it goes downward into the valve to have the valve closed and kept sealed. Because of the available with the above principle of cam, the force of the closing part which acts at the seat ring will be gradually enlarge during open and close, that is the surface of the part contacts the seat ring from complete come-away and the specific pressure of sealing gets gradually enlarged till being completely sealed, vice versa. This makes the previous sealing state and effect of the ball valve greatly improved. The semi-ball valve is applicable for the cases of high temperature high pressure and easy crystallization and serious worn-out.

Applicable cases

Per the purpose, the semi-ball valve can be divided into: universal valve, pipeline valve, slurry used valve, gas used valve, petrochemical used valve, coal power spraying and blowing used valve six series, and used for petroleum, chemical, metallurgy, electric power, gas, ash discharge, coal powder spray etc. industries and as the update products for gate valves, stop valves and Y-type valves.