Ball valve is a kind of valve that the ball rotates around the center line of the valve body to open and close. Ball valves are mainly applied in pipeline to cut off, distribute and change the flow direction of medium. Fluid resistance is small, and its resistance coefficient is equal to that of the same length pipe. Tight and reliable, the sealing surface material is plastics, with good sealing performance and has been widely used in vacuum systems. Easy to operate, quick to open and close, only need to rotate 90 degrees from full open to full close, easy to control over long distances. When fully open or fully closed, the sealing surface of the ball and seat is isolated from the medium. When the medium passes through, it won’t cause the erosion of the sealing surface.