A floating ball valve 

 The ball valve is floating in the medium pressure, the sphere can produce a certain displacement and pressed on the export side of the sealing surface to ensure that the Sealing. 
 Floating ball valve of simple structure, good seal, but the sphere to work under medium load all pass the export seals, and therefore to consider the ring material can stand the sphere medium work load. This structure is widely used in low-pressure ball valve. 

 Second, the fixed ball 

 The ball valve is fixed, the compression of the move. Fixed ball valve with a floating valve seat, by the media pressure, the valve seat to move, and seals pressed on the ball, in order to ensure sealing. Usually in with the ball in the upper and lower shaft fitted with bearings, operating torque, suitable for high pressure and large diameter valves. 

 Valve seals in order to reduce the operating torque of the ball valve and increase the reliability of the seal, in recent years both in the sealing surface pressure between the injection special lubricant to form a layer of film, which enhances the sealing, and reduce operating torque more suitable for high pressure large diameter ball valves. 

 , Elastic ball valve 

 The ball valve is flexible. Ball and the valve seat ring made of metallic materials, sealing pressure greatly rely on the pressure of the medium itself has reached less than sealing requirements, you must apply force. This valve is applicable to high temperature and pressure medium. 

 Elastic sphere is the bottom of the sphere wall to open a flexible tank, to obtain flexibility. When the channel is closed, the wedge-shaped head of the stem so that the sphere up to open to achieve compression seal with the valve seat. To release the wedge-shaped head before rotating sphere, the sphere followed by restoration of the original prototype, a small gap between the ball and valve seat sealing surface can reduce the friction and operating torque. 

 Ball valve according to the channel positions can be divided into straight-through, tee and rectangular type. The latter two ball valves for the distribution media and change the flow of media. 

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