Vacuum valve is a valve whose working pressure is lower than the standard atmospheric pressure.
Vacuum valve refers to the vacuum system component, which is used to change the direction of the air flow, adjust the size of the gas flow, cut off or connected to the pipeline. Vacuum valve closures are sealed with rubber seals or metal seals.
Two Common Forms of Connection
1. Looped flange connection:
This the most used form of connection in the valve. According to the shape of the combination, it can be divided into the following:
(1) Smooth type: Valves used for low pressure.
(2) Concave-convex type: The working pressure is high, and the medium hard washer can be used.
(3) Tongue and groove: The gasket with large plastic deformation can be used widely in corrosive medium, and the sealing effect is better.
(4) Trapezoidal groove: Use an oval metal ring as a gasket for valve with a working pressure of more than 64 kg/cm, or a high temperature valve.
(5) Lens type: Gasket is a lens shape and made of metal, for working pressure ≥100 kg/cm high pressure valve, or high temperature valve.
(6) O-ring type: This is a newer form of flange connection, and the sealing effect is more reliable than the average flat washers.
2. Threaded Connection
This is a simple connection method, often used in small valves:
(1) Direct seal: Internal and external threads directly from the sealing effect. In order to ensure that the connections do not leak, and often filled with lead oil, linen and PTFE tape. PTFE which has good corrosion resistance, excellent sealing effect, easy to use and save, can be completely removed when disassembled.
(2) Indirect seal: Thread tightening force, passed to the gasket between the two planes, so that the gasket sealing effect.
3.Quick-release flange connection
Use the clamp to seal the O-ring with the body flange to achieve a better seal.
1. Nominal diameter
Nominal diameter mean outside diameter, and the identification mark is “DN”, which is the general diameter of various pipes and pipe fittings. Pipe and pipe fittings with the same nominal diameter can be connected with each other and are interchangeable. It is not the actual pipe diameter or inner diameter. Although its value is close to or equal to the pipe inner diameter, in order to make the connection dimensions of pipes and fittings uniform, the nominal diameter is adopted. Each nominal diameter, corresponding to an outer diameter, the diameter of the value varies with the thickness of different.
2. Nominal pressure
The identification mark is “PN”, and maximum working pressure permitted under certain temperature. The control valve on the carbon steel body refers to the application of the following 200 ℃ maximum allowable working pressure. Cast iron body, the maximum working pressure allowed under 120℃. When the working temperature increases the pressure of the valve body decreases. Therefore, the nominal pressure control valve to determine not only based on the maximum working pressure, but also based on the highest working temperature and material properties, not just to meet the nominal pressure greater than the working pressure.
Electromagnetic vacuum charging valve and Electromagnetic vacuum pressure differential valve are specially used to prevent the mechanical vacuum pump from returning to the oil. The vacuum valve is mounted on the intake port of the mechanical vacuum pump and synchronized with the pump on and off.
Flapper valve is used in the angle connector and T-connector of vacuum pipe. Drive mode (Manual, pneumatic, electromagnetism, electric) is determined by the user. With a wide range of application, the GDC-J electromagnetic high vacuum baffle valve is sealed by metal bellows, and it can be used as inflation valve. Also, the GDC-J electromagnetic high vacuum baffle valve can be installed wherever needed.
Gate valve is used in situation which needs high vacuum or large pipe size. With bidirectional sealing, the drive mode (Manual, pneumatic, electric) is determined by the user, and both pneumatic mode and electric mode have signal feedback device.
Diaphragm valves and ball valves are all straight-through type valves, and they can be used in situation which holds positive pressure and vacuum both. Drive mode (Manual, pneumatic, electric) is determined by the user.
Butterfly valve is a kind of straight-through type valve, the drive mode (Manual, pneumatic, electric) is determined by the user. Manual opening angle of butterfly valve is adjustable, the opening angle of intelligent pneumatic mode and electric mode is adjustable too.
Operating Conditions of The Valve
1.The medium is pure air or non-corrosive gas.
2.The temperature of the medium is determined by the extreme temperature of the rubber used.