What is a vacuum valve? The valve with nominal pressure lower than standard atmospheric pressure is called vacuum valve.
Vacuum valve can be divided into three categories according to working pressure, i.e. vacuum degree:
Low vacuum valve: the absolute pressure is 101325 ~ 0.133Pa
High vacuum valve: absolute pressure is 0.133 ~ 1.33 × 10-6pa
Ultra high vacuum valve: the absolute pressure is 1.33 × 10-6 ~ 1.33 × 10-10pa
① Vacuum valve for petrochemical industry
Vacuum valve for petrochemical industry, usually used in chemical fiber industry, high-grade grease refining and other equipment systems. It is required that the valve can be used in both low vacuum system and pressure system. The pressure of the vacuum system is usually 0.005~0.133Pa, and the pressure of the pressure system is 1.0~4.0MPa.
The structure is usually DC type, Y-type vacuum stop valve, which is basically the same as the ordinary Y-type stop valve.
② Vacuum valve for metallurgical machinery industry
The metallurgical machinery industry usually uses vacuum or high vacuum valve, which is used in vacuum smelting, vacuum deoxidation, vacuum heat treatment, vacuum casting, electrical insulation treatment and other equipment of high-grade alloy steel.
③ Vacuum valve for nuclear industry
In the field of nuclear industry, various kinds of vacuum valves are widely used. In the research of high-energy physics and controlled thermonuclear fusion, high vacuum and ultra-high vacuum valves are used; in the isotope separation plant, high vacuum and low vacuum valves are used.
In general, metal bellows or diaphragm are used as valve disc sealing elements, and vacuum stop (throttle) valve with high cleanliness is required.