How to select the triple eccentric butterfly valve and double eccentric butterfly valve?

The sealing pair of the sealed butterfly valve has a metal-to-metal hard seal and a metal-to-rubber or plastic soft seal. The sealing ring can be placed on the butterfly plate or on the valve body. According to the position of the butterfly plate in the valve, butterfly valves are divided into centerline butterfly valves, single eccentric butterfly valves, double eccentric butterfly valves, and triple eccentric butterfly valves. This article will briefly introduce their structural characteristics and applications.