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The bearing gets hot again, what should we do?

Source:未知Author:HONBbearing06 Addtime:2020-06-18 Click:

The bearing gets hot again, what should we do?


High bearing temperature is a common and harmful fault of rotating equipment, which will reduce the service life of the bearing and increase the maintenance cost. When the temperature rises quickly and exceeds the standard, it will easily lead to unplanned shutdown or reduced load operation of the unit, which has a great impact on economic benefits.Therefore, to quickly determine the cause of the failure and take appropriate measures to solve it is the guarantee for the continuous safe operation of the equipment.(HONBbearing06)
After luoyang Hongyuan bearing technical personnel long-term summary of the following several, there may be a lot of we have not encountered, welcome everyone in the following message to inform, we will sort out one by one, sent to you collection.
Common causes of high bearing temperature
1) Poor lubrication, such as insufficient lubrication or excessive lubrication, the quality of lubricating oil does not meet the requirements, deterioration or debris;
2) Insufficient cooling, such as pipeline blockage, inappropriate use of cooler, and poor cooling effect;
3) The bearing is abnormal, such as bearing damage, poor bearing assembly process, and the gap adjustment of each part of the bearing box does not meet the requirements;
4) Large vibration, such as the poor alignment process of the coupling does not meet the requirements, the rotor has dynamic and static imbalances, poor foundation rigidity, virtual feet, rotating stall and surge.
When the bearing temperature is high, the problem should be solved from the following aspects:
1) Insufficient refueling amount, too little or too much lubricating grease
The bearing box should be refueled regularly in accordance with the requirements of the work. After the bearing is lubricated, sometimes the temperature will be high, mainly due to too much lubricating. At this time, the phenomenon is that the temperature continues to rise. After reaching a certain point (generally about 10 to 15 degrees Celsius higher than the normal operating temperature), it will remain unchanged, and then it will gradually decrease.
 
2) The grease added to the bearing does not meet the requirements or is contaminated
Inappropriate selection of lubricating grease, it is not easy to form a uniform lubricating film, can not reduce the friction and wear inside the bearing, insufficient lubrication, bearing temperature rise. When different types of grease are mixed, a chemical reaction may occur, causing the grease to deteriorate and agglomerate, reducing the lubrication effect. Contaminated grease will also increase the bearing temperature.
Therefore, suitable grease should be selected, and the bearing box and bearings should be cleaned during inspection and maintenance. The oil pipeline should be inspected and unblocked. Different types of grease are not allowed to be mixed. If other types of grease are replaced, the original grease should be cleaned first; Grease should be added regularly, and grease should be properly stored for moisture and dust prevention measures.
 
3) Not enough cooling
Check whether the pipeline is blocked, and whether the temperature of oil inlet and return water exceeds the standard. If the cooler is not selected properly, the cooling effect is poor, and the use requirements cannot be met, it should be replaced in time or a new cooler should be installed in parallel. The axial flow induced draft fan should also check the insulation and tightness of the core tube.
 
4) After confirming that the above problems do not exist, check the alignment of the coupling and the bearing
The alignment of the coupling must meet the process standards. When aligning axial flow induced draft fan, hydraulic coupler, etc., the problem of thermal expansion of the equipment during operation should also be considered. The bearing box rises on the impeller side of the induced draft fan due to heat; the temperature rises during the operation of the fluid coupling. The bearing box expands and the bearing rises. Therefore, the motor is higher when the timing is adjusted. The size of the reserve depends on the characteristics and Depending on the temperature parameter in operation.
The inspection of bearings mainly has the following points:
1) Bearings quality
During the disassembly of the bearing box, first of all, check whether the grease has bad conditions such as deterioration, agglomeration, and impurities, which is an important basis for judging the cause of bearing damage. Secondly, check the bearing for bite and wear; check the surface finish of the bearing inner and outer rings, rolling elements, cages and for defects such as cracks, rust, peeling, pits, overheating and discoloration, and measure whether the bearing clearance exceeds the standard; check Whether the bushing is worn, pitted, or peeled. If there is any of the above conditions, new bearings should be replaced.
 
2) Coordination of bearings
When the bearing is installed, it is very important to match the inner diameter of the bearing with the shaft, the outer diameter and the housing. When the fit is too loose, the mating surface will produce relative sliding called creep. Once the creep occurs, it will wear the mating surface and damage the shaft or casing, and the wear powder will invade the inside of the bearing, causing heat, vibration and destruction. When the interference is too large, the outer diameter of the outer ring will become smaller or the inner diameter of the inner ring will become larger, reducing the internal clearance of the bearing. In order to select the fit for the application, various factors such as the nature, size, temperature conditions of the bearing load, and the rotation of the inner and outer rings must be considered.
 
3) Adjustment of the fit clearance of each part of the bearing
If the bearing clearance is too small, due to the excessive shear friction loss of grease in the clearance, the bearing will also be heated. At the same time, if the clearance is too small, the amount of oil will be reduced, too late to take away the heat generated by the friction, will further increase the temperature rise of the bearing . However, if the gap is too large, it will change the dynamic characteristics of the bearing, causing unstable rotor operation. Therefore, it is necessary to select a suitable bearing clearance for different equipment and use conditions.

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