Centrifugal Compressor End Thrust Bearing Maintenance
In order to ensure that centrifugal compressors operate safely and stably, regular maintenance is essential. The end thrust bearing is an important part of the centrifugal compressor, and its maintenance should not be ignored.
End thrust bearings refer to the bearings mounted at the ends of the centrifugal compressor rotor axis. It can support the axial force of the impeller and avoid the rotation due to the axial force of the impeller, but does not support the radial force of the rotor. The bearing has two directions: one end bears the axial force of the impeller and overturns the axis, and the other end prevents the impeller from moving backwards and maintains the axial action.
The first step of end thrust bearing maintenance is to check the axial force of the Running rotor. The precise value of the axial force should be measured with a dynamometer. If the measured value exceeds 15% of the nominal value, the end thrust bearing requires additional maintenance.
If the axial force of the rotor is too high, in addition to inspecting the end thrust bearing, you should also check the centering of the impeller and whether the parts have caused wear, corrosion or damage. If the concentricity of the impeller is checked and no parts are found to be worn, corroded or damaged, the gap between the bearing and the journal must be adjusted.
It is important to remember that when adjusting the gap, never loosen both ends of the end thrust bearing, as this will cause misalignment of the shaft and damage to the bearing. Therefore, it is necessary to loosen the end of the end thrust bearing where the axial force is excessively large and adjust only this gap; and the other end gap should remain unchanged.
In order to ensure the consistent accuracy of the end thrust bearing gap, it is necessary to check the gap in two directions: the axial direction and the circumferential direction. The axial direction gap should be between 0.020 and 0.032 inches, and the circumferential direction gap should be between 0.015 and 0.025 inches.
The maintenance of end thrust bearing also requires that the bearing is regularly lubricated. Lubrication of bearing includes two aspects: grease lubrication and oil lubrication. Grease lubrication is mainly used for the bearing at the drive end because of the lower temperature. The amount of grease for each bearing should not exceed 72kg. Oil lubrication should be used for the bearing at the driven end, and the lubricating oil should be filtered and of sufficient viscosity.
Before lubricating the end thrust bearing, it is necessary to confirm the type of bearing, bearing model and size, bearing model, bearing clearance, rotating speed, viscosity and oil temperature, etc. The lubricating oil should be filtered before lubricating the bearing, and the filtered lubricating oil should meet the requirements of the relevant industry standard. The lubrication of end thrust bearing shall be carried out when the main compressor is on. The amount of oil injection should not exceed the rated value of the bearing. The oil should be injected until the bearing is heated.
In summary, the maintenance of the end thrust bearing must be careful and well done or it is too easily damaged. The end thrust bearings must be regularly checked, and the appropriate lubrication should be applied to ensure the stable operation of the compressor.
