Ball valve is evolved from the plug valve. It has the same 90 degree rotation action, except that the plug body is a sphere with a circular through hole or passage through its axis. The ratio of the sphere to the channel should be such that when the sphere is rotated 90 degrees, the sphere should be fully spherical at the inlet and outlet to cut off the flow. Ball valve only need to rotate 90 degrees of operation and a small turning moment can be closed tight. The completely equal body cavity provides a medium-sized, straight-through runner with low resistance. Ball valves are generally considered to be the most suitable for direct opening and closing, but recent developments have designed the ball valve to be throttling and controlling flow. The main features of the ball valve is its compact structure, easy operation and maintenance, suitable for general working media such as water, solvents, acids and natural gas, but also for media with bad working conditions such as oxygen, hydrogen peroxide, methane and ethylene. Ball valve body can be a whole, it can be combined.