Oil-free dry machinery Vacuum pump principle and introduction

An oil-free dry mechanical vacuum pump (also referred to as a dry mechanical pump) means that the pump can start to pump air from atmospheric pressure and discharge the pumped gas directly to the atmosphere. There is no oil or other working medium in the pump chamber, and The ultimate pressure of the pump is the same as or close to the mechanical vacuum pump of the oil-sealed vacuum pump.



At present, most mechanical vacuum pumps used in the vacuum industry use oil, water, or other polymer fluids as the pump's working medium, and play a variety of roles such as cooling, sealing, and lubrication within the pump. With the development of science and technology and the expansion of vacuum applications, there are two urgent problems to be solved in the existing mechanical vacuum pump and the pumping system it consists of: First, the backflow of the pump's working medium contaminates the pumped container. Flow affects the quality and quantity of the product in many cases and increases the maintenance cost of the equipment. Second, because of the reactive substances in some processes, the medium in the vacuum pump is seriously degraded, so that the pump cannot work normally.



For ordinary oil-free vacuum systems, although oil-sealed vacuum pumps can be used to prevent backflow by adding cold traps, adsorption traps, and the like, this does not completely solve the problem and makes the system appear complicated. With the use of an appropriate type of dry mechanical vacuum pump, the desired results can be achieved.



The application of dry mechanical vacuum pumps is extensive, mainly in the following aspects: 1) polysilicon production process in low pressure chemical vapor deposition; 2) semiconductor etching process. In these production processes, corrosive gases and abrasive particles are often used or generated; 3) Some processes that generate particulates, other than semiconductor processes, do not want particulates to be incorporated into pump oils, but they are expected to use particulate discharge pumps. The dry mechanical vacuum pump can meet the requirements; 4) in the chemical industry, pharmaceutical industry, food industry distillation, drying, defoaming, packaging, etc., to prevent organic solvent pollution, suitable for dry vacuum pump; 5) used as general Oilless vacuum system foreline pump to prevent oil contamination.



In recent years, dry mechanical vacuum pumps have developed rapidly. Many large vacuum companies in the world have developed new types of dry mechanical vacuum pumps. Many domestic units have also been working on the development of dry mechanical vacuum pumps, such as Northeastern University, Shenyang Vacuum Technology Institute, and Shanghai Vacuum Pump Plant. At present, dry mechanical vacuum pumps are mainly classified into contact type and non-contact type. Contact type dry pumps have vane type, cam type, reciprocating piston type, diaphragm type, etc. These pumps have low speed and are suitable for small capacity and high compression ratio (single stage compression ratio). Non-contact dry pumps include Roots type, claw type, screw type, vortex type, etc. They have higher speeds and are suitable for large capacity and low compression ratio (refer to single-stage compression ratio). Different types of dry pumps have their own characteristics. It can be selected according to different purposes when used.


For more information, please consult China Vacuum Pump Trading Network. (/)


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