What should We do if the pump bearing heats up?

High bearing temperature is a common and more harmful fault in rotating equipment, which reduces its service life and increases the cost of maintenance. The economic impact is huge. Therefore, it is important to quickly determine the cause of the failure and take appropriate measures to address it in order to operate the device with frequency and safety.

Common causes of excessive bearing temperatures

Poor lubrication, such as insufficient or excessive lubrication, the quality of the lubricating oil does not meet the requirements, deterioration or debris;

Insufficient cooling, such as pipeline blockage, improper selection of cooler, and poor cooling effect;

Abnormal bearing, such as bearing damage, poor bearing assembly process, and the gap adjustment of each part of the box does not meet the requirements;

Vibration is large, for example, the alignment process of the coupling does not meet the requirements, the rotor has a dynamic and static imbalance, the foundation rigidity is poor, and the ground is weak, resulting in rotational stall and surge.

Solution

When the temperature is high, the problem should be solved from the following aspects:

Too little or too much oil in the wrong quantity.

The bearing housing should be regularly refueled as required by the job. After it is led, sometimes the temperature will be high, mainly due to excessive 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 gradually decrease.

The grease added to the bearing does not meet the requirements or is contaminated

The selection of lubricating grease is not suitable, it is not easy to form a uniform lubricating oil film, it cannot reduce the friction and wear inside it, the lubrication is insufficient, and the temperature rises. When different types of grease are mixed, a chemical reaction may occur, causing the grease to deteriorate, agglomerate, and reduce the lubricating effect.

Contamination of the grease will also increase the temperature, and dust will fall into the grease during the process of adding grease, causing grease pollution, resulting in the deterioration of the grease inside the housing, destroying the lubrication, and increasing the temperature.

Therefore, appropriate grease should be selected, the housing should undergo maintenance, and the refueling pipeline should be checked and dredged. Different types of grease should not be mixed. If other types of grease are replaced, the original grease should be cleaned. Regularly add grease, grease should be properly stored for moisture-proof and dust-proof measures.

not cooling enough

Check to see if the pipe is blocked and if the temperature of the inlet oil and the temperature of the return water are above standard. If the choice of cooler is not suitable, the cooling is poor, and cannot meet the requirements of use, it should be replaced in time, or a new one should be installed in parallel.The axial flow-induced draft fanflow-induced checks the insulation and sealing of the core cylinder.

After confirming that the above problems do not exist, check the alignment of the coupling and bearings

The alignment of the coupling must meet the technological standards. Thermal expansion of the device during operation should also be taken into account when aligning the axial-flow-induced and the axial-flow-induced couplers.

The impeller side of the induced draft fan expands due to heat, and the box rises; during the operation of the hydraulic coupling, the temperature rises, the box expands, and it rises, so the motor should be higher when aligning, and the size of the reserved amount depends on the characteristics of the equipment and depends on the operating temperature parameters.

The inspection of bearings mainly includes the following points

Bearing quality

During the dismantling of the bearing housing, check whether the lubricating grease has bad conditions such as deterioration, agglomeration, impurities, etc., which is an important basis for judging the cause of Bearing damage

Secondly, check whether it is bitten and worn; Examine the surface finish of the inner and outer rings, the roll elements, and one of the cages for defects such as cracks, rust, flaking, pits, overheating, and discoloration, and measure whether the bearing clearance is above standard; Check to see if the bushing is worn, pitted, or peeling, and if any of the above is the case, replace it with a new bearing.

Bearing fit

The matching of the inner diameter of the bearing to the shaft, and the outer diameter to the housing, is very important when the bearing is fitted. When the fit is too loose, the mating surface creates a relative slip, known as creep. Once creep occurs, it can wear down the mating surface and damage it.