Principle: When fully opened, the unimpeded valves on both sides form a straight pipe channel and are sealed in both directions. The pneumatic O-ring ball valve has better self-cleaning performance, and is suitable for two position cutting occasions that are especially dirty and contain fiber media. The ball core always rubs with the valve during the opening and closing process of the valve. At the same time, the sealing between the valve core and the valve seat is achieved by the pre tight sealing force of the valve seat against the ball core. However, due to the excellent mechanical and physical properties of the soft seal valve seat, its sealing performance is particularly good.

Analysis of composition and characteristics of maintenance free rotary compensator
The maintenance free rotary compensator is composed of a reducer, an inner sleeve, a seal seat outer sleeve, flexible graphite packing, N compression spring combinations of nuts and bolts, a packing gland and a spring compression flange: a compression spring is arranged between the packing compression flange and the compression upper flange, and the longitudinal section of the compression flange is a U-shaped groove ring. The U-shaped groove ring and the two fixed rings on the right end face of the inner guide tube are provided with a ball type rolling ring which is matched with the reducer tube.
Maintenance free working principle: maintenance free rotary compensator and rotary compensator products are applied by the flexible packing in the packing chamber to stop sealing. During the application of the product, the packing will wear a little every time it rotates. When the wear reaches a certain value, the product will leak. The maintenance free rotary compensator has added a set of springs above the packing compression flange. When the packing shows slight wear, it will be compensated by the tension of the compression spring, thus extending the leakage time of the product (the leakage time is delayed by 3-5 years). When the amount of wear exceeds the amount of spring tension compensation, it is only necessary to tighten the nut above the spring compression flange. There is no need to stop air for repair. There is no limit on the number of operations, and leakage is not easy to occur, thus greatly improving the social and economic benefits of gas supply units and gas users. The product will not leak after 5000 times of compensation under the pressure of 4.0Mpa, and the sealing effect is excellent. Diameter of maintenance free rotary compensator: DN50-DN600 maintenance free thrust free rotary compensator is used for displacement compensation installation of heat supply network pipes, mainly composed of inner and outer pipes, sealing packing and bolt compression installation. The utility model is characterized in that the fit clearance between the bolt compression flange and the inner pipe is small by high-precision processing wrist. The utility model is applicable to two to three combination of absorption compensation for the axial displacement and axial thrust of the heat supply network pipe. The product has good sealing performance, no need to stop production and maintenance. Moreover, the product adopts fine processing, which makes the coordination between product parts more reasonable, the assembly more accurate, and ensures the product concentricity. Only when the product accepts angular and lateral displacement can it be greatly improved, and the stability is good, and the safety and sealing of the product are improved.