The three eccentrics of the three-eccentric valve are: axial eccentricity, spherical eccentricity and sealed surface eccentricity. 

 Three eccentricity 

 (1) The offset of the valve plate relative to the center of the valve body; 

 (2) The offset of the valve shaft relative to the center line of the valve body; 

 (3) The center line of the valve shaft is offset from the axis of the cone angle of the valve seat. 

 Characteristics of three eccentric valves 

 (1) Good sealing performance: The sealing of the three-eccentric butterfly valve is achieved by squeezing between the sealing surfaces of the valve. The greater the closing torque, the higher the sealing level, and "zero leakage" can be achieved. 

 (2) Zero friction: It reduces the friction phenomenon of the valve during the switching process, greatly increasing the service life of the valve. 

 (3) Large flow rate: Due to the superiority of the three-eccentric structure, the circulation diameter of the valve is increased, and the valve has a high flow rate. 

 (4) Short stroke: When the valve is opened and closed, the valve shaft only needs to rotate between 70-90°, which shortens the opening and closing time of the valve and can achieve quick closing. 

 (5) Wide range of use: The three-eccentric metal sealed butterfly valve has a wide temperature and pressure adaptation range. The temperature can be from -196-650℃, and the pressure can be from PN10-PN160 (ANSI CL 150~CL900). 

 (6) Long service life: The three-eccentric metal sealing butterfly valve is a metal-to-metal sealed valve with good wear resistance and long-term work without deformation. In addition, at the moment of opening, the valve seat and the sealing ring are detached without friction, so the valve has an extremely long service life. 

 (7) Adjustment performance: The three-eccentric metal sealed butterfly valve has an adjustment function and is often used as a regulating valve.