The Best Solution for Heating When Bearings Are In Use

Time：2021.06.17  Source：Roller Bearings Suppliers

High bearing temperature is a common and harmful fault of rotating equipment, which will reduce the service life of bearings and increase maintenance costs. When the temperature rises quickly and exceeds the standard, it is easy to lead to unplanned outage or load reduction 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 of the continuous and safe operation of the equipment.

Common causes of excessive bearing temperature

1) Improper amount of oil, too little or too much lubricating grease

The bearing box shall be regularly refueled according to the requirements of the work.The bearing will sometimes have high temperature after refueling, mainly because of too much refueling.At this time, the phenomenon is that the temperature continues to rise, and after reaching a certain point (generally about 10℃~15℃ higher than the normal operating temperature), it will remain unchanged, and then it will gradually decline.

2) The grease added to the bearing does not meet the requirements or is polluted The selection of lubricating oil is not appropriate, it is not easy to form a uniform lubricating oil film, can not reduce the internal friction and wear of the bearing, insufficient lubrication, and the bearing temperature rises.When different types of grease are mixed, chemical reactions may occur, resulting in deterioration and caking of the grease, reducing the lubrication effect.Oil pollution will also increase the bearing temperature. Dust falls into the grease in the process of greasing, resulting in oil pollution, deterioration of the oil inside the bearing box and damage to bearing lubrication, and the temperature rises.Need WSBC 22310 E,Click here to learn more.

Therefore, appropriate grease should be selected. The bearing box and bearings should be cleaned during maintenance, and the refueling pipeline should be checked and dredged. 

Different types of grease are not allowed to be mixed.Add grease regularly during operation and maintenance, and the grease should be properly kept for moisture-proof and dust-proof measures.

3) Insufficient cooling

Check whether the pipeline is blocked and whether the inlet oil temperature and return water temperature exceed the standard.If the cooler is not selected properly, the cooling effect is poor, and the operation requirements cannot be met, it should be replaced in time or a new cooler should be installed in parallel.The axial induced draft fan should also check the heat preservation and sealing of the core barrel.

4) Check the alignment of the coupling and the bearing after confirming that the above problems do not exist

The coupling must be found according to the process standard.In the alignment of axial induced draft fan and hydraulic coupler, the problem of thermal expansion of equipment in operation should also be considered.The impeller side of the induced draft fan expands due to heat, and the bearing box rises;The temperature of the hydraulic coupler increases in the operation of the bearing box, the bearing rises, so the alignment motor should be higher, and the size of the reserve should be based on the characteristics of the equipment and the temperature parameters in the operation.

The inspection of bearings mainly includes the following points:

1) Quality of bearings

During the disintegration of the bearing box, first of all, check whether the lubricating grease has deteriorated, agglomeration, impurities and other undesirable conditions, which is an important basis for judging the cause of bearing damage.Secondly, check whether the bearing is bitten and worn;Check the surface finish of the inner and outer ring of the bearing, the rolling body and the cage as well as whether there are defects such as cracks, rust, peeling, pits, overheating and discoloration, and measure whether the bearing clearance exceeds the standard;Check whether the shaft sleeve is worn, pits, peeling, if the above situation should be replaced with a new bearing.Click here to learn more about WSBC 22219-E1.

2) Bearing matching

When the bearing is installed, the match between the inner diameter of the bearing and the shaft, the outer diameter and the shell is very important. When the match is too loose, the match surface will produce relative sliding called creep.Once the creep occurs, it will wear the mating surface, damage the shaft or the shell, and the wear powder will invade the bearing interior, causing heating, vibration and damage.When the interference is too large, it will cause the outer diameter of the outer ring to become smaller or the inner diameter of the inner ring to become larger, reducing the internal clearance of the bearing.In order to choose suitable match for the purpose, the nature of bearing load, size, temperature conditions, the rotation of the inner and outer rings should be considered.

3) Adjustment of the fit clearance of each part of the bearing

Bearing clearance is too small, because the oil in the clearance shear friction loss is too large, will also cause bearing fever, at the same time, clearance is too small, the amount of oil will reduce, too late to take away the heat generated by friction, will further improve the temperature rise of the bearing.However, if the clearance is too large, the dynamic characteristics of the bearing will be changed and the rotor operation will be unstable.Therefore, it is necessary to select the verified bearing clearance for different equipment and use conditions.