Vacuum valve in vacuum system of function
1. Open and close the air loop. When valve 1 and valve 4 are closed and valve 2 is opened, the mechanical vacuum pump vacuums three pairs of vessels, and the air flow flows through the pre-vacuum pumping circuit. When valve 2 is closed and valve 4 is opened, the mechanical pump can independently vacuum the diffused pump. When valves 1 and 4 are opened simultaneously, the diffusion pump and the mechanical pump can work simultaneously to empty the container and the air flow through the diffusion pump. The role of the valve in this operation is to switch the air path and change the flow path of the air flow.
2. Control air flow and adjust vacuum degree. In Figure 1, the cover opening Angle of regulator 1 regulates the flow of air through the line. Shutoff valves 2 and 4. The inlet of the mechanical pumps can be discharged into the atmosphere through the vent valve 3. The vacuum in the container can be adjusted by exhaust valve 5.
3. Quantitative inflation: There is a small hole of a certain size in the plunger of the glass valve. When the hole turns to the right and is connected with the high-pressure gas cylinder, the hole can be filled with high-pressure gas. When it turns to the left and is connected to the vacuum vessel, it puts this volume of high-pressure gas into the vessel, thus acting as a quantitative aerator.
Vacuum system requirements for valves
For most vacuum systems, vacuum valves should have the following broad properties.
1. Rust resistance
Materials in contact with the vacuum environment must have good rust resistance. Therefore, aluminum, copper and stainless steel are widely used to manufacture vacuum isolation parts.
2. The working pressure ranges from 0 to 2.5×105Pa
Relatively wide pressure range, will make the use of a wider range of products, and the valve plate sealing had better be two-way, at least in the valve plate against atmospheric pressure can also be sealed.
3. Low leakage rate
In the high vacuum field, the leakage rate should be less than 10-7pa · L · S-1. The lower leakage rate is conducive to improving the efficiency of the system and is very effective in reducing the production cost.
4. Low vibration and small impact on the system during starting.
5. Compact structure and light weight
6. Obvious valve position indication
7. The valve opening and closing signal controller is optional for programming and automatic control.
8, high flow conductance
9. Bellows are adopted as the displacement dynamic seal
No dynamic leakage, no grease pollution, high reliability, relative to rubber seal, higher reliability and can avoid particle pollution.
10. Avoid using vacuum grease for the vacuum part.
11. Minimize the useless space in the vacuum parts to ensure less time for vacuum.
12. Reduce power consumption as much as possible