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The pressure resistance level, operating temperature, and corrosion resistance of the valve body should not be lower than the requirements of the process connection pipeline, and priority should be given to selecting products that have been approved by the manufacturer.
Cast iron valves should not be used for steam or wet gases with high moisture content, as well as flammable and explosive media.
When the ambient temperature is below -20 ℃, cast iron valves should not be used.
In the Cartesian coordinate system composed of medium temperature and pressure difference with severe cavitation and erosion, when the temperature is 300 ℃ and the pressure difference is 1.5 mpa, the throttle sealing surface shall be made of wear-resistant materials, such as cobalt base alloy or surface surfacing stellite alloy.
For highly corrosive media, the selection of corrosion-resistant alloys must be based on the type, concentration, temperature, and pressure of the media, and appropriate corrosion-resistant materials must be selected.
The valve body and throttle components are treated separately. The throttle speed on the inner wall of the valve body is small and allows for a certain degree of corrosion, and the corrosion rate can be around 1mm/year; Throttling components may experience high-speed erosion and corrosion, leading to increased leakage. The corrosion rate should be less than 0.1mm/year.
When selecting lining materials, the temperature, pressure, and concentration of the working medium must meet the range of use of the material, and consider the physical and mechanical damage caused by valve action.
Vacuum valves should not be lined with rubber or plastic structures.
Rubber lined materials should not be used for the two position shut-off valves in water treatment systems.