High standard fixed ball valve closing member ball rotates around the center line of the valve body to achieve opening and closing. The sealing member is embedded in the stainless steel valve seat, and the end of the metal valve seat is equipped with a spring. When the sealing surface is worn or burned, Under the action of the spring, the valve seat and the ball are pushed to form a metal seal. It has a unique automatic pressure relief function. When the medium pressure in the valve cavity exceeds the spring preload force, the valve seat at the outlet end retreats from the sphere to achieve the effect of automatic pressure relief. After pressure relief, the valve seat automatically resets. It is suitable for water, solvent, acid And natural gas and other general working media, but also suitable for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene, etc., are widely used in various industries.