Track BALL valve according to the structure of the form can be divided: A floating ball valve: ball ball is floating, under the medium pressure, the ball can produce a certain displacement and tight pressure on the export end of the sealing surface, to ensure that the export end of the seal. The structure of the floating ball valve is simple and the sealing is good, but the ball bearing the load of the working medium is all passed to the outlet sealing ring, so it is necessary to consider whether the sealing ring material can withstand the working load of the sphere medium. This structure is widely used in low and medium pressure ball valves. Two, fixed ball valve: ball ball is fixed, pressure does not produce movement. Fixed ball valve with floating seat, by medium pressure, seat movement, so that the sealing ring pressed on the ball, to ensure sealing. Bearings are usually installed on the upper and lower shafts of the ball, and the operation torque is small. It is suitable for high pressure and large caliber valves. In order to reduce the operating torque of the ball valve and increase the reliability of the seal, in recent years, the oil seal ball valve has appeared, not only in the sealing surface pressure injection of special lubricating oil, to form a layer of oil film, that is to enhance the sealing, and reduce the operating torque, more suitable for high pressure and large caliber ball valve. Three, the elastic ball valve: the ball valve is elastic. Ball and seat ring are made of metal materials, sealing ratio pressure is very large, relying on the pressure of the medium itself has not reached the requirements of sealing, must apply external force. This valve is suitable for high temperature and high pressure media. The elastic sphere is an elastic groove at the lower end of the inner wall of the sphere, and the elasticity is obtained. When CLOSING THE CHANNEL, USE THE WEDGE TIP OF THE STEM TO OPEN THE BALL AND PRESS THE SEAT TO SEAL. By RELEASING THE WEDGE HEAD BEFORE TURNING THE BALL, THE BALL RETURNS TO ITS ORIGINAL SHAPE, ALLOWING A SMALL CLEARANCE BETWEEN THE BALL AND THE SEAT, REDUCING FRICTION AND OPERATING TORQUE ON THE SEALING SURFACE.