Symmetrical axis of the valve, flange connection structure of the neutral, and can be used for the end of the pipeline: its simple structure, excellent performance, widely used, easy accessibility,rubber vulcanization in the body wall, and contacts with the body wall no leakage: solid rubber lining to prevent its movement during assembly and redundancy, the reliability and durability.Needed can be equipped with handles, turbine, pneumatic and electric drive and remote controldevice to achieve