Vacuum valves used in the electronics industry

Along with our country the development of electronic industry, vacuum unit in order to meet the new production process, the complex of the vacuum system USES many valve to control, in order to make the system pipe length is shorten, improve the ability to guide, simplifying the system structure, and convenient for operation and manufacturing, has been gradually moving towards the combination valve, a valve is used to replace several valve work, and centralized control. Applied to vacuum unit combination valve (also called multiple block valve) structure, in this valve, vacuum, high vacuum, such as charge, discharge gas valve, and according to the operation needs, can be conveniently used three handle, control of high vacuum pump, vacuum pump, gas storage barrel of gas (male), inflatable bottle (or pipe) and container (refer to the vacuum chamber) pathway on or off, to make them separate, connected with the container or series, or completely isolated, thus is advantageous to the various process operations. The working vessel may be mounted on the upper part of the valve body or on the side.
Valves are used in vacuum units to separate parts of the system. According to its working characteristics, it can be divided into pre-vacuum valve and high-vacuum valve.

The main difference between them is the size of the inlet diameter and the vacuum seal structure. Exit diameter of the former, generally at about 15-20 millimeter, multi-purpose vacuum rubber gasket seal, used for vacuum part, while the latter is the diameter of 65, 100, 150, 180 mm or more, multi-purpose metal sealing pad (especially for ultra-high vacuum valve), only limit vacuum below 10 to 6 when, with rubber seal is more. They are widely used in materials, such as brass, steel, stainless steel, etc., because of the porosity of casting, vacuum valves do not need casting.

For the valve stem and the cap or with the main body of sealing, nothing more than two kinds of rubber, metal bellows, film (refers to the valve with bronze or nickel skins, thickness 0.1 0.15 mm film seal lined, generally the reciprocating stroke for 2-4 mm) with less.

The sealing at the valve hole, usually with a vacuum rubber. With conical valve plate (made from soft material, nickel silver or brass) and round to form the seat (with hardened steel) of the linear fit closely sealed, due to its poor durability (such as valve plate to slightly skewed, seating surface processing is flawed, and excessive pressure valve plate and squeeze the seat, can make the valve no longer closely and repairs). Only used in ultra high vacuum. Oil seal and liquid metal seal have few applications except some systems with high vacuum degree and small pipe size.

When designing the vacuum valve, the working characteristics, reasonable design structure and technical conditions should be paid full attention to. The following main requirements should be met:

1) no air leakage shall be allowed anywhere in the valve.

2) the connection part of the valve and the sealing of the valve when it is closed shall ensure the vacuum tightness and reliability. The sealed parts are best replaceable.

3) the inlet and outlet of the valve and the valve cavity should be as straight as possible, so that the air flow should be less turned, and when the valve is opened, there should be enough large space for air supply to flow through and good permeability.

4) the switch operation of the valve should be light and convenient, and the pole position (on, off, air release…) ) the operation sequence and rotation direction shall be marked and positioned.

5) all metal parts of the valve (especially the inner surface) shall be corrosion resistant, steam driven down and surface smooth.

6) the valve structure should be simple and easy to manufacture, and the welding seam should be reduced to the minimum. Use less or avoid structures (such as vacuum welding) that are difficult to process under special processing and conditions at your own plant.