The butterfly valve adopts a structure in which the valve plate rotates along the center line, so the valve is small in size. The valve can be opened by rotating the handle 90 degrees or driving by a worm gear to make the valve plate parallel to the medium flow direction. Therefore, the butterfly valve has the characteristics of simple structure, small size, light weight, small installation size, convenient operation, and rapid opening and closing. It also has sealing and flow regulation characteristics. However, due to the large resistance of the valve disc, the medium pressure has a great influence on the opening and closing of the valve, so it is not suitable for high-pressure environments. In the past, butterfly valves were restricted by technology and sealing materials, and most of the structures were soft seals of the center line type, that is, the valve seat was mostly rubber, plastic, and the butterfly plate was metal or metal covered with rubber or plastic. In recent years, with the rapid development of science and technology, butterfly valves have developed new structural types, and the eccentric metal sealing butterfly valve is one of them. The valve seat and butterfly plate sealing surface of the eccentric metal sealing butterfly valve are made of metal carbide materials, or the butterfly plate is made of soft and meatl materials, so that the butterfly valve can be resistant to high temperature, low temperature, abrasion, erosion, good sealing performance, and long service life, so it is widely used.
