What is the sealing principle of wedge gate valve?

The sealing principle of the wedge gate valve is sealed by the tight combination of the two sealing surfaces on the wedge disc and the two sealing surfaces on the valve body when wedging. The purpose of using the wedge disc is to increase the auxiliary sealing load, so that the metal-sealed wedge gate valve can seal both high medium pressure and low medium pressure. When closing, rotate the valve stem clockwise to make the sealing surface of the valve disc and the sealing surface of the valve body close to achieve sealing. 

However, the sealing specific pressure at the inlet end produced by the wedging action of the metal-sealed wedge gate valve is often insufficient to achieve the inlet end sealing due to the force of the medium. Therefore, the metal-sealed wedge gate valve is a single-sided forced seal.

More details of wedge gate valves, please go to  https://www.mingpinmetals.com/Gate-Valve-pl3117724.html