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Analysis on the Components and Principle of Vacuum Coating Machine

The chamber of vacuum coating machine – according to the difference of processing product requirements, the size of vacuum chamber is also different. Currently there are more applications such as 0.9 M、1.3M、1.5M、1.8M. The chamber is made of stainless steel, which requires no rust and solid, each part of the vacuum chamber has a valve link, which is used to link each pumping pump.

The auxiliary vacuum pumping system: the vacuum pumping system is an important part of the coating vacuum system, which consists of three parts: mechanical pump, booster pump / Roots pump and diffusion pump. This vacuum pumping system as: diffusion pump+ mechanical pump+ Roots pump+ low temperature cold trap+ polycold. Pumping flow: the mechanical pump first pumping the vacuum chamber to a low vacuum condition of less than 2.0*10-2 PA, which provides the premise for the subsequent vacuum pumping of the diffusion pump, and then when the diffusion pump is vacuuming, the mechanical pump is in series with the oil diffusion pump to complete the pumping action in this way.

Mechanical Principle and Classification of Vacuum Coating Machine:
Mechanical pump: also known as the front pump, mechanical pump is a widely used low vacuum pump which by oil to maintain the sealing effect and rely on mechanical methods to constantly change the volume of the suction chamber in the pump, so that the volume of gas in the pumped container expand to obtain vacuum.

one. Classification of mechanical pumps: There are many types of mechanical pumps, commonly used are sliding valve type (mainly used for large equipment), piston reciprocating type, fixed plate type and rotary plate type (this is widely used at present)

Two.The mechanical pump works from the atmosphere, its main parameters are ultimate vacuum, pumping speed, this is an important basis for the design and selection of mechanical pump, single stage pump can pump the chamber from the atmosphere to the ultimate vacuum of 1.0*10-1 PA, and the double stage pump can pumping the chamber from the atmosphere to 6.7*10-2 PA, or even higher. The pumping speed refers to the volume of gas that can be discharged in unit time when running at rated speed. It can be calculated by formula: Sth=2 nVsSth=2 nfsL. fs means the no loading chamber cross-sectional area at the end of suction, and the chamber length is L. The coefficient indicates that the rotor has two pumping processes per rotation. The effect of mechanical pump exhaust is also related to the number of motor rotation and belt tightness, when the motor belt is relatively loose, motor rotation is very slow; the mechanical pump pumping effect will also become worse, so regular maintenance, spot inspection are needed. And mechanical pump sealing effect also need regular spot inspection,if oil too little, can not achieve sealing effect, pump will leak;if oil too much, suction hole clogging, can not inhale and pumping. Generally under the oil level of 0.5 cm is ok.

Three. Mechanical pump is often used to remove dry air, but can not remove the gas of oxygen content too high, explosive and corrosive. Mechanical pump is generally used to remove long-lasting gas, but there is no good effect on water steam, so it can not remove water steam. The main components in the rotary vane pump are stator, rotor, shrapnel and etc. The rotor is inside the stator but is not concentric with the stator, like two inner tangent circles, the rotor slot is filled with two shrapnels, and the middle of the two shrapnel is equipped with a spring, which ensures that the shrapnel is tightly attached to the inner wall of the stator.

 


Post time: Mar-16-2020
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