CONTROL ANALYSIS OF OIL RETURN RATE OF OIL DIFFUSION PUMP

With the continuous development of vacuum technology, vacuum equipment has been widely applied in metallurgical industry. As the main pump of most high vacuum systems, oil diffusion pump has many advantages, such as simple structure, high pumping rate, easy to obtain high vacuum and so on. However, it is difficult to solve effectively in production practice for many years. In this paper, how to control the oil return rate of oil diffusion pump in order to obtain high vacuum system is discussed from the design principle of oil diffusion pump and the experience accumulated in production practice.

THE STRUCTURE AND WORKING PRINCIPLE OF OIL DIFFUSION PUMP:

The oil diffusion pump carries the gas through the oil vapor jet to achieve the goal of vacuum pumping. Oil diffusion pump structure. It is mainly composed of pump body, draft tube, fractionating ring and heater. Oil as working fluid in the oil pan below, heated by heater into oil vapor, rises along the diversion pipe, when oil vapor to the first, second and third-class nozzle, due to the sudden reduction of the cross-section of the nozzle, the speed of steam flow increases, high-speed oil vapor flow from the nozzle ejected, forming an umbrella, as long as the gas molecules touch Oil vapor is easily carried away, and then reaches the inner wall of the pump, the pump wall is cooled by cooling water, so oil vapor is condensed into oil droplets, along the pump wall into the oil pan, gas molecules can not be condensed out; oil is heated, evaporated into oil vapor, the first level of the gas molecules from the A1 zone to A2 zone A3 It is then sent to the exhaust port and pumped by the front stage pump to achieve exhaust.