The emergency cut-off ball valve ball is fixed and does not move under pressure. Fixed ball ball valve with floating seat, by the medium pressure, seat movement, so that the sealing ring on the ball, to ensure sealing. Usually equipped with bearings on the upper and lower shafts of the ball, with small operating torque, emergency cut-off ball valves are suitable for high pressure and large diameter valves. In order to reduce the operating torque of the ball valve and increase the reliability of the seal, the emergence of oil sealing ball valve, emergency cut off the ball valve not only in the sealing surface between the 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 large diameter ball valve.
The ball of the emergency cut-off ball valve is elastic. Ball and seat sealing ring are made of metal materials, sealing pressure is very large, relying on the pressure of the medium itself has not reached the requirements of sealing, must apply external forces. This valve is suitable for high temperature and high pressure medium. Elastic sphere is an elastic groove at the lower end of the inner wall of the sphere to obtain elasticity. When closing the access, the emergency cut-off ball valve USES the wedge head of the stem to expand the ball and squeeze the seat to seal. Stainless steel ball valve before rotating the ball first release the wedge head, the ball then restore the original shape, stainless steel ball valve makes a small gap between the ball and the seat, emergency cut off the ball valve can reduce friction and operating torque of the sealing surface.
Emergency cut-off ball valve is simple, easy to repair, sealing surface and sphere are often closed, not easy to be medium erosion, in various industries have been widely used. American standard ball valve enterprises need to change the existing production relations to strengthen technical innovation in the face of the increasingly serious homogenization problem, now the emergency cut off ball valve gradually in the wireless cycle into the escape of vicious competition. In this severe situation, valve companies need to clearly recognize that low cost, low technology valve products flooded the market, not only disrupt the consumer's judgment and purchase desire, American standard ball valves also hinder the mature transition of the valve market. Therefore, if the enterprise wants to improve the production efficiency, it must first change the existing production relationship, increase the investment in the modern production line, and strengthen the technical innovation.