Excessive bearing temperature is a common harmful failure of rotating equipment, which will reduce the service life of the bearing and increase maintenance costs. When the temperature rises rapidly and exceeds the standard, it is easy to lead to unplanned shutdown or load reduction of the unit, which has a great impact on economic benefits.
Therefore, quickly determining the cause of the failure and taking corresponding measures to solve it is the guarantee of continuous and safe operation of the equipment.
What causes a bearing temperature to be too high?
Top1. Common causes
1) Poor lubrication, such as insufficient or excessive lubrication, unqualified lubricating oil quality, deterioration or impurities;
2) Insufficient cooling, such as pipeline blockage, improper selection of cooler, poor cooling effect;
3) Bearing abnormalities, such as bearing damage, poor bearing assembly process, and the clearance adjustment of each part of the bearing seat does not meet the requirements;
4) Large vibration, such as the misalignment process of the coupling does not meet the requirements, the rotor has dynamic and static imbalance, poor foundation stiffness, ground foot weakness, rotary stall and surge.
5) The ambient temperature at the customer's site is too high.
The bearing temperature rises, if it is allowed to rise, the bearing will lock, and in severe cases, the compressor will be damaged; High bearing temperatures can affect bearing service life. Bearing damage can lead to damage to the associated accessories. This issue deserves attention.
Top2. Settle
When the bearing temperature is high, the problem should be solved from the following aspects:
1) Improper oil injection, too little or too much grease.
The bearing housing should be regularly oiled according to the engineering requirements. Sometimes the bearing temperature is higher after oil injection, mainly due to excessive oil injection. At this time, the temperature continues to rise. After reaching a certain point (generally about 10 °C ~ 15 °C higher than the normal working temperature), the temperature will remain unchanged and then gradually decrease.
2) The grease added to the bearing is not compliant or is contaminated.
Improper selection of grease makes it difficult to form a uniform lubricating oil film and cannot reduce the internal wear and wear of the bearing. Due to insufficient lubrication, the bearing temperature rises. When mixing different types of greases, chemical reactions may occur, causing the grease to deteriorate and agglomerate, reducing the lubrication effect. Oil contamination can also increase bearing temperatures. During the lubrication process, dust will fall, causing oil contamination, causing the oil in the bearing housing to deteriorate, damaging bearing lubrication and raising the temperature.
Therefore, the appropriate grease should be selected. During maintenance, the bearing housing and bearings should be cleaned, and the oil injection pipeline should be checked and unclogged. Different types of grease should not be mixed. If other types of grease are replaced, the original grease should be cleaned first; During operation and maintenance, grease should be added regularly. Grease should be kept properly and moisture-proof and dust-proof measures should be taken.
3) Insufficient cooling.
Check whether the pipeline is blocked, and whether the oil inlet temperature and return water temperature exceed the standard. If the cooler is not properly selected, the cooling effect is poor, and it cannot meet the requirements of use, the new cooler should be replaced in time or installed in parallel. The axial induced draft fan should also check the heat preservation and sealing of the core cylinder.
4) After confirming that there are no above problems, check the alignment of the coupling and bearing.
The alignment of the coupling should meet the process standards. In the alignment of axial induced draft fans and fluid couplings, the thermal expansion of the equipment in operation should also be considered. Thermal expansion on the impeller side of the induced draft fan causes the bearing housing to rise; When the temperature of the fluid coupling rises during operation, the bearing housing expands and the bearing rises. Therefore, the alignment motor should be higher, and the reserved amount should be determined according to the characteristics of the equipment and the temperature parameters during operation.
First of all, the air compressor should be maintained normally and use grease that matches the motor. The air compressor workplace should maintain a ventilated environment to facilitate heat dissipation.
