Introduction to the selection of vacuum valve materials

Vacuum valve material selection

(1) The pressure resistance grade, service temperature and corrosion resistance of the valve body should not be lower than the requirements of the process connection pipe, and the manufacturer's styling products should be preferred.

(2) Water vapor or wet air containing more water and flammable and explosive medium should not be used.

(3) When the ambient temperature is lower than -20 °C (especially in the north), it is not suitable to use cast iron valves.

(4) For the rectangular arc coordinates of the medium temperature and pressure difference where the cavitation and erosion are more serious, the temperature is 300 ° C, and the pressure difference is 1.5 MPa. Abrasion resistant materials such as cobalt-based alloys or surface-welded Struers.

(5) For highly corrosive media, select the corrosion-resistant alloy according to the type, concentration, temperature and pressure of the medium, and choose the appropriate corrosion-resistant material.

(6) The valve body and the throttle member are treated separately, the throttle wall of the valve body has a small throttle speed and allows corrosion, and the corrosion rate can be about 1 mm/year; the throttle member is subjected to high-speed erosion and corrosion will bow [increasing leakage The corrosion rate should be less than 0.1mm/year.

(7) When the lining material (rubber, plastic) is selected, the temperature, pressure and concentration of the working medium satisfy the use range of the material, and consider physical and mechanical damage (such as shear failure) when the valve is operated.

(8) Vacuum valve should not be used to line the rubber and plastic structure of the valve body.

(9) The two-way shut-off valve of the water treatment system should not be made of rubber-lined material.

(10) Typical corrosion resistant alloy material selection for typical media: