The BN series three eccentric butterfly valve adopts a three-dimensional eccentric structure for the valve plate. When opening and closing, there is almost no friction between the valve seat and the disc plate. The disc plate sealing ring is a multi-layer stainless steel and graphite composite plate sealing ring with excellent sealing performance. This valve has a large diameter, low operating torque, low flow resistance, and reliable sealing, making it suitable for working conditions with large diameters, low flow resistance, and small leakage.