Oil-free dry-type mechanical vacuum pump working principle brief introduction

do mechanical oil-free vacuum pumps (also referred to as dry-type mechanical pump) is the atmospheric pressure from the pump exhaust start, while gas will be pumped directly into the atmosphere go, pumping cavity without oil or other medium, but also the limits of pump pressure and vacuum pump oil seal or near the same order of magnitude of the mechanical vacuum pump. At present, the use of vacuum in the industry are the majority of mechanical vacuum pump oil, water or other polymers, such as fluid pumps to serve as working media, in the pump from cooling, sealing, lubrication and many other roles. With the development of science and technology, as well as the expansion of the field of vacuum application, the original mechanical vacuum pump and its components of the exhaust system of the urgent need to address two questions: First, the work of medium reflux pump contaminated containers be selected, and such reflux in many cases the impact of product quality, quantity, increased equipment maintenance costs. Secondly, because of some process-reactive substances in the process of vacuum inside so that the serious deterioration of the medium, so that pumps can not work properly. For a general oil-free vacuum system, while the oil seal vacuum pump can be used together with the cold trap or trap Absorption like attachment to prevent reflux, but will not completely solve the problem, but the system seems complex. The use of appropriate types of dry-type mechanical vacuum pump, you can achieve the desired results. Do mechanical vacuum pumps are a wide range of applications, mainly in the following areas: 1) low-pressure chemical vapor deposition of polysilicon in the preparation process; 2) semiconductor etching process. In these production processes tend to use or generate corrosive gases and abrasive particles; 3) In addition to semiconductor process outside the particles produced in certain processes, do not want particles mixed with oil-pumping, and the hope that particulate emissions from pumps, the type used must Do the mechanical vacuum pump to meet the requirements; 4) In the chemical industry, medicine industry, food industry distillation, drying, defoaming, packaging and so on, to prevent pollution caused by organic solvents, suitable for dry-type vacuum pump; 5) to make general Clean oil-free vacuum pump system before class in order to prevent oil pollution. In recent years, dry-type mechanical vacuum pump has been rapid development, foreign companies have large vacuum developed a new type of dry-type mechanical vacuum pump. Domestic units have been much do mechanical vacuum pump to develop the job, such as Northeastern University, Shenyang Institute of Vacuum Technology, Shanghai Vacuum Pump Factory, etc.. At present, the dry-type Mechanical vacuum pumps are mainly classified into contact type and non-contact type. Contact type do have vane pump, cam-type, reciprocating piston, diaphragm-style and so on, the lower the speed of such pumps for small-capacity high compression ratio (single-stage compression ratio). Non-contact type do have Roots-type pump, claw-type, screw type, scroll type, etc., the higher the speed, the application of large-capacity, low compression ratio (referring to a single-stage compression ratio). Do different types of pump has its own characteristics. When used according to different uses to select