METAL SEATED BALL VALVE
With such features as small fluid resistance, smooth flow channel, rapid opening and closing, and easy automatic control, the ball valve has been widely used. But the seat of regular ball valves is generally made of PTFE and other nonmetal materials. Limited by seat materials, the regular valves cannot be used under the service condition of high temperature. Therefore, the use of regular ball valves is limited to a certain degree. The series of new style practical metal seated ball valve products are newly designed to solve the above problem, and have been widely applied in petroleum, chemical industry, e electric power, metallurgy, light industry and etc.
The metal seated ball valve is used to cut off or connect the media in various pipelines. It is suitable for severe service conditions containing solid granules, slurry, coal power, cinder and etc.
1. Advanced Ball And Seat Hardening Technology
The ball and seat of the metal seated ball valve absolutely adopts the sealing mode of metal to metal. According to different service conditions and requirements of users, various advanced ball and seat hardening technologies can be adopted, including HVOF coating, nickel-base alloy spray welding, high nickel alloy spray welding, nickel-base alloy tungsten carbide alloy spray welding, cobalt-base hard alloy spray welding, etc. Generally, the heat resistance of the sealing face material can reach 540℃～60 with the maximum value of 980℃. The sealing face material has also good wear resistant and impact resistant performances.
2. Flexible Valve Opening And Closing
Under the service condition of high temperature, the ball and seat will expand too much because of thermal expansion, and thus causing that the valve cannot be opened. The ball valve adopts the disc spring or spring loaded sealing structure so that thermal expansion of parts under high temperature can be absorbed by the disc spring or spring, and it is ensured that the valve will be flexibly opened and closed under high temperature without expanding too much under high temperature.
3. Fireproof Structure Design
In the metal to metal sealing structure for the valve, the gasket is the stainless steel + flexible graphite and the packing is the flexible graphite. Therefore, reliable sealing of the valve can be ensured even in case of fire.
4. Double Block And Bleed(metal Seated Trunnion Ball Valve)
The metal seated trunnion ball valve usually adopts the sealing structure before the ball. When the valve is closed and the middle cavity is emptied through the discharge valve, the upstream and downstream seats will independently block the fluid at the inlet and outlet to realize double block function.
The metal seated floating ball valve usually adopts the sealing structure after the ball. Unidirectional sealing is generally adopted with flow direction marked on the body. If users have special requirements, bidirectional sealing structure can be adopted.
5. Reliable Sealing Performance
The unique ball grinding technology is adopted. Through rotation of the ball and the grinder at different positions, the ball surface will achieve high roundness and fineness. The low pressure sealing of valve seat is realized by spring pre-tightening. In addition, the position effect of valve seat is designed reasonably, which realizes high pressure sealing by the pressure of the medium itself. The sealing level of the valve meets the requirement of level IV B16.104.