On the issue of temperature fluctuations in tilting pad bearings
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One of the centrifuge units in our factory uses tilting-pad bearings; the shaft journal has a 90 degree angle, the rotation speed is over 10,000 revolutions per minute, and it consists of a rigid shaft. It is common for the bearing temperature to rise rapidly, for example from 90°C to 100°C, before gradually falling again. As the temperature rises, vibration levels decrease; whereas when the temperature falls slowly, vibration levels increase. Instrument issues have been ruled out; it’s likely a mechanical problem. I hope everyone can help analyze what’s causing this issue. If the machine stops working, which components need to be checked, and which ones should be given priority?
This condition is a instability of the sliding oil film. As the oil temperature rises, the viscosity of the oil changes, which reduces the load-carrying capacity of the oil film and leads to instability in the operating trajectory of the shafting. Additionally, a similar situation occurs when there is a sudden change in the shafting load. Solution: 1. Check the bearing shell clearance. 2. Check the operating condition of other shaft systems. Note: Please indicate whether it is a centrifugal compressor or a material centrifugal liquid separator (commonly referred to as a centrifuge).
Generally, an increase in temperature and greater vibration are normal. Yours has become smaller; it definitely isn’t caused by mechanical friction. Then it comes down to the oil circuit issue; the oil film changes with temperature. Check the gap between the tiles and ensure that the oil flow is unobstructed. Check whether the quality of the lubricating oil has excessive machine impurities
It’s probably a problem with the lubricant; what type of compressor do you have?
From a process perspective as well, changes in the amount of air intake, its temperature, or its composition can affect the rotational balance of the rotor, which is reflected in the shaft temperature~~
I suggest you do two things: 1. Check the oil temperature and oil pressure； 2. Your tiles may not move freely or may have carbon buildup on their surfaces, which reduces the stability of the oil film!