Domed valves rely on compressed air to achieve a tight sealing effect of the special valve, suitable for handling dust-laden gases, abrasive cut bulk material. Dome valves are widely used in almost all industries. The unique closure and sealing action of the dome valve allows it to operate continuously and reliably under special conditions of wear, heat, corrosion or stickiness, which conventional valves can not do well. We can first understand its working process: dome valve closing process - when the dome valve ring is completely relaxed (not inflated) state, there is a certain gap between the valve core and seat. Spool rotation, the material with the spool rotation, some through the gap into the container, and some remain in the gap. When the spool is rotated to the closed position, the ring begins to inflate and tightly wrap the various shapes of particles in the gap to the edge of the spool. The dome valve is fully closed. Dome Valve Opening Process - Before the valve is opened, the seal is degassed until completely relaxed. Between the spool and the valve seat back to the original gap, the spool began to rotate to open position. We used the traditional valve, there are generally two forms of seal: one is a hard seal, one is a soft seal. This hard seal valve is by increasing the machining accuracy of the mating surface, and enhance the hardness of the valve seat and valve body material, by the surface of the crushing material particles sealed. This frequent with the valve open, the sealing surface wear gradually increased until it can not be used; and traditional soft-sealed valves used in the flexible ring is not by expansion, but by the bite force to seal, poor wear resistance, the role of small compensation . The dome valve is sealed by an inflatable seal. When the spool rotates, there is a reasonable gap between the spool and the seat, so there is almost no wear on the spool and seat. When the valve is closed, the particles in the gap are tightly wrapped by the expanded sealing ring and adhered to the edge contacting the valve seat by the pressure difference between the inside and outside of the sealing ring to completely cut off the stationary or flowing material. There is no relative movement between the material particles and the sealing ring, which greatly reduces the wear of the sealing ring. Moreover, the sealing ring can automatically compensate for wear and tear under the condition of inflation due to its elastic effect. Therefore, the use of the sealing ring is greatly enhanced. Temperature valve (<200 ℃) and high temperature valve (280 ℃ ~ 350 ℃), semi-high temperature valve (200 ℃ ~ 280 ℃); According to the installation position can be divided into: inlet valve Non-standard flange, the import flange for the standard flange) and the discharge valve (for the pipeline, import and export flanges are standard flanges) can be divided according to the use of pressure: PN1.0, PN1.6, ANSI150 ; According to the material can be divided into: cast iron A278, 304 stainless steel, 316 stainless steel, lined with Teflon. Therefore, the dome valve can be applied to different temperature and pressure conditions, can transport a variety of solid materials (general materials, corrosive materials, abrasive material), and a variety of installation forms. In addition, for some explosion-proof places and higher temperature conditions, but also special custom. Dome valve because of its unique structure and processing technology, reliable performance, under normal operating conditions, each operation only needs 1 million maintenance time. Seals are the only wear parts. Sealing ring is a flexible part, located between the support ring and the top plate, fastened by fasteners, very easy to remove and overhaul. To ensure the dome valve work, the seal must take care of certain internal and external pressure, otherwise it will lead to leakage of air between the seal and the valve core, seriously damaging other parts of the dome valve.