Is there any relationship between the oil pressure in the expander of an air separation unit and the speed of the expander?
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I have a question for everyone. Recently, in the air separation industry, I encountered a situation where the speed of the operating expander suddenly dropped to around 1000 revolutions per minute; at the same time, the oil pressure also decreased by about 0.1 MPa. The gas flow rate and pressure fluctuated as a result. No obvious abnormalities were found upon inspection. Later, by slightly opening the nozzle, the parameters returned to their normal values. (Preliminarily suspected that the expander nozzle is moving, but it cannot be confirmed yet.) ) Is there an inevitable connection between the decrease in the speed of the expander here and the subsequent drop in oil pressure? Please ask an expert in air separation to answer our questions and clear up our doubts. Thank you! :)
As the rotor speed increases, the relative friction with the bearings rises, which causes a certain increase in temperature of the lubricating oil. The viscosity of the oil decreases, and the oil pressure also drops to some extent; therefore, manual adjustment is sometimes necessary. Of course, a constant pressure valve can be used to maintain stable oil pressure~~
The main oil pump is driven by the expander gearbox; when its speed decreases, the speed of the oil pump also decreases, and consequently the oil pressure drops
As the rotation speed decreases, the centrifugal force on the rotor diminishes; the gap between the rotor and the bearing shells increases. As a result, more oil can flow through, and the oil pressure will certainly drop
The expansion oil pump is not a shaft-mounted pump; it is driven by a separate motor, so there is no issue with a decrease in the pump’s rotation speed~~
I’ve never seen it; which manufacturer makes the expander? Personally, I don’t think there should be such a large difference.