Gas rate of oil diffusion pump
The pumping speed of the oil diffusion pump remains unchanged within a wide range of inlet pressure. At this time, the pumping speed of the pump is independent of inlet pressure. However, under low and high inlet pressure, the pumping speed of the pump tends to decrease.
In the low inlet pressure range, with the decrease of pressure, the reverse diffusion of the gas from the front stage through the steam jet increases and the pumping speed decreases. In addition, under low inlet pressure, the steam flow from the boiler releases gas and the pump wall release gas also start to affect the pump pumping speed. When the steam condensate returns, the compressed gas dissolves in the condensate and returns to the boiler together, releasing it as the re-vaporized steam returns to the high vacuum nozzle. This part of gas greatly affects the limit pressure of the pump and reduces the pumping speed. When the total amount of gas released by the diffusion gas and steam flow and the gas released by the pump wall is equal to the gas pumped out by the pump, the pumping speed is close to zero.
When the inlet pressure of the pump within the scope of work, pump pumping the gas in the smoke from the container quantity is bigger, at this time due to the diffusion, pump wall is deflated and release of gas from oil condensation reflux gas volume compared with the swept volume of the pump has been negligible, thus the pumping speed and inlet pressure of the pump has nothing to do at this time.
Extraction, to start the pump inlet pressure is higher, swept volume is also a large number of gas molecules into the steam jet molecular collision and steam flow, make the directional movement of steam jet velocity attenuation, the results of the steam flow shock waves moving in the direction of nozzle, the steam jet pump with wall. At this point, the gas will flow back from the front stage side, so that the pump pumping speed is lower, close to the pumping speed of the front stage pump.
Pump pumping speed is affected by many factors, such as the type and temperature of the gas being pumped. Geometric dimensions of the pump; The type of pump oil and the state of steam jet (related to nozzle structure and heating power, etc.) as well as pump outlet pressure.
(The article comes from the Internet. If reprinting is not allowed, please contact our company to delete it.)