The minimum stable pressure at the inlet end of the rotary vane vacuum pump is the limit vacuum of the pump.
Rotary vane vacuum pump is the same as general mechanical pump. The limit vacuum on the pump refers to the vacuum measured by absolute vacuum gauges such as rotary Maxwell gauge for permanent gas. It is usually 10-4 tonnage, and the best one can reach 10-6 tonnage. However, due to the influence of various vapors and oil and gas, the limit vacuum is only l0-2-10-3 Torr for all gases (equivalent to the pressure value measured by thermocouple). In order to improve its vacuum limit, water absorbent (such as phosphorus pentoxide, etc.), oil absorbent (such as 13X molecular sieve, activated alumina, etc.) or liquid nitrogen cold trap can be added between the pump and the pumped parts or the later stage high vacuum pump. Proper use of vacuum tanks can also be beneficial.
There are many factors affecting the ultimate vacuum, such as the structure of the pump, the performance of the oil, the amount of oil and the working temperature. After using for a period of time, the limit vacuum of the pump will be reduced a little. Of course, it can be recovered and improved by repairing and adjusting.
2. Pumping rate and characteristics of rotary vane vacuum pump
Pumping rate: At a certain pressure and temperature, the volume of gas pumped from the container in a unit time is called pumping rate.
The name brand gives the nominal pumping speed of the pump, that is, the theoretical pumping speed of the pump.
3. Design and Accounting Method of Geometric Parameters of Rotary Vacuum Pump
The design method of geometric parameters of rotary vane vacuum pump is often used in maintenance. Because some pump geometry size changes greatly in maintenance, parameters such as pumping rate should be estimated and corrected according to the actual data. At the same time, the size of some parts can be amended accordingly.
没有评论:
发表评论