Choice of vacuum pump in electronic industry
The vacuum is obtained by means of the vacuum pump. Different types of pump, it has certain working conditions and range, when choosing vacuum pump, it should take full consideration of its characteristics and specifications, and start from the following four conditions of the designed system.
(1) volume (including pipeline) and productivity requirements of the evacuated vacuum container.
(2) required vacuum degree.
(3) types of gases extracted.
(4) in the course of work, the release of the workpiece and the system of the gas olives and leakage.
At present, the basic types of vacuum pumps commonly used in China’s electronics industry are mainly mechanical pumps and oil diffusion pumps (sometimes with condensing Wells). The selection of these two types of vacuum pumps (metal) is briefly described as follows.
The basic principle of the mechanical pump is to use the rotor to compress and expand the working space of the mechanical pump periodically, so as to expel the gas from the container (which flows into the mechanical pump through the conduit).
Mechanical pumps can be divided into rotary vane vacuum pumps, fixed vane vacuum pumps, slide valve vacuum pumps, multiple vane direct air pumps and dual rotor vacuum pumps (roots pumps) according to their structural characteristics.
At present, rotary vane vacuum pump is widely used in China’s electronic industry. The performance of mechanical pump is affected by many factors, such as structure shape, machining precision, performance of mechanical pump oil, working environment, type of gas being pumped and wear of machine parts. Someone recently although in theory from the harmful space, air tightness and ultimate pressure of pump, extraction rate and life expectancy, etc after analysis, think the slide valve type, the best chip times, turning vane is poorer, but has yet to provide powerful evidence.
Vacuum pump machine city at present, the general has can reach 10-3 ~ 5 * 5 * 10-4 mm about mercury, and high vacuum degree requirements, simply by a mechanical pump is fulfilled, also must use diffusion pump (when the vacuum degree required 10-6 ~ 10 – mercury into more than 7 mm, still need to add with other parts of vacuum) to continue to complete the mechanical pump can achieve vacuum degree.
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