The steel gate is composed of rubber water seal, locking beam and sliding block of gate frame. In addition to sealing water, locking beams are set at both left and right ends of the gate. When maintenance is required, the door is supported in the slot. The slide block is made of oil-based nylon, which has good corrosion resistance and friction coefficient, which is only one third of that of steel.
Steel gate internals mainly refer to the sealing surface, valve stem and bushing (upper seal seat) of valve closure parts. The selection principle of internal parts material is based on the main material, medium characteristics, structural characteristics and the role and stress of parts. For conventional general-purpose valves, the internal parts materials have been specified or several materials have been specified to be selected by the designer according to the specific conditions. For some valves with special requirements, such as high temperature, high pressure, medium corrosion and other working conditions, the internal material shall be selected according to the working conditions of steel gate.
The sealing surface of the closing part is one of the main working faces of the valve. Whether the material selection is reasonable and its quality directly affects the function and service life of the valve.
Working conditions of sealing surface of closure parts:
As the valve is widely used, the working conditions of valve sealing surface are very different. The pressure can be from vacuum to ultra-high pressure, the temperature can be from - 269 ℃ to 816 ℃, and some working temperature can reach 1200 ℃. The working medium ranges from non corrosive medium to strong corrosive medium such as acid and alkali. From the stress of the sealing surface, it is squeezed and sheared; from the point of view of friction, there are wear and tear, corrosion wear, surface fatigue wear, erosion and so on. Therefore, we should choose the appropriate sealing surface material according to different working conditions.