Operation labor-saving: the medium pressure on the ball to generate the force is transmitted to the upper and lower bearings, the ball will not move relative to the position, the two ends of the valve seat sealing force is uniform, low operating torque. Adopting spring pre-loaded movable metal seat structure, it can be applied to high temperature, high pressure and all kinds of media pipeline. According to the customer's requirements, it can be designed to apply to the media containing particles, slurry and so on. Widely used in food, medicine, petroleum, chemical, natural gas, steel, environmental protection, paper and other media pipeline.