Types of Vacuum Valves
1. According to the working pressure, there are low vacuum valves, high vacuum valves, and ultra-high vacuum valves.
2. According to the structural characteristics, there are vacuum flapper valve, gate vacuum valve, butterfly vacuum valve, ball valve, diaphragm valve, angle vacuum valve, straight-through valve, and three-way valve.
3. According to the transmission principle, there are manual, pneumatic, electric, and electromagnetic. Generally, pneumatic is the process of electromagnetic pilot and cylinder performing actions, and it can also be used to control the pilot valve cylinder to perform actions by hand. Electric for both hand and electricity, and can be operated manually when the power is cut off.
4. According to the material, there are valves with stainless steel, carbon steel, and aluminum alloy as the main material.
5. According to the material of the dynamic seal, it can also be divided into the metal seal and non-metal seal valve. The О-shaped rubber ring used for the shaft seal generally has a leakage rate of 10-4Pa.L/S, and the vacuum degree is not high during the shaft movement process, so it can be used under high vacuum conditions with low requirements; the shaft seal is a metal corrugated The tube is sealed with a leak rate of 10-7Pa.L/S, suitable for use under ultra-high vacuum conditions.
The flapper vacuum valve is often installed in the corner and tee placed in the vacuum pipeline. The driving mode is manual, pneumatic, electromagnetic, and electric.
The gate vacuum valve is used on occasions where the vacuum degree is high or the pipe size is required. The leakage rate of the valve is 10-7Pa.L/S, and it is sealed in both directions. Drive mode manual, pneumatic, electric. Both pneumatic and electric have signal feedback devices.
The diaphragm valve and ball valve are straight-through types and can be used in situations where positive pressure and vacuum coexist. The drive modes are manual, pneumatic, and electric.
The butterfly valve is a straight-through valve with three driving modes: manual, pneumatic, and electric. The manual butterfly valve opening angle is arbitrary
1. The valve should be kept clean and stored in a dry room.
2. Valves stored for a long time should be checked regularly to prevent moisture, rust, and aging of rubber parts.
3. Before installation, the surfaces of the valve in contact with the vacuum should be cleaned according to the vacuum hygiene requirements.
4. The flange connected to the valve must not have protruding weld scars in the connection hole, and the orifice must be chamfered.
5. When the valve is installed, it must be concentric with the flanges on both sides.
6. When the valve is not used for a long time and is stored, the valve should be in a slightly open state.
7. If the valve is overhauled and reassembled, the vacuum performance test must be carried out.
1. The connecting flanges should be consistent
2. It is best to check whether the valve is in good condition and whether the accessories are complete before the valve is in the hands of the user.
3. The air source pressure of the pneumatic valve is required to be 0.4~-0.6MPa.
4. The signal switch of the pneumatic valve cannot directly withstand AC220V, and there is a current limit. A relatively large resistance should be connected in series, greater than 1KQ. If DC is used, please pay attention to the correct polarity connection.
5. After the plug-in valve is closed, when one side of the valve plate is in a vacuum and the other side is in the atmosphere, it is not allowed to open the valve, otherwise it will damage the parts of the plug-in door or affect its sealing performance. Only when the pressure on both sides of the valve plate is basically balanced (the pressure difference is less than 2700Pa), the valve is allowed to open.
6. The allowable baking temperature of the valve body is less than or equal to 150℃.
7. The newly used pneumatic valve may encounter a high air source pressure required for closing, which is a normal phenomenon, and the air source pressure required for closing will drop after a large number of actions.
8. The electromagnetic vacuum belt inflation valve is allowed to work horizontally or vertically, but it should not be installed upside down.
9. For the welded diaphragm valve, the user must remove the valve body when welding to prevent the diaphragm from being damaged by high temperatures. At the same time, care should be taken not to have welding debris falling into the valve body cavity, which will affect the sealing performance.
10. The vacuum valve should be handled gently to prevent strong vibration and keep it clean and dry.
11. Pneumatic flapper vacuum valve can be installed in any direction below the nominal diameter of 160mm. The vacuum under the valve plate and the atmosphere above the valve plate can maintain a good vacuum seal. The flapper valve with a nominal diameter of more than 200mm should generally be installed vertically.