Reasons for the damage of the self-cooling bearing in German KSB heat transfer oil pumps after one day of use

Routine maintenance: 1. Shut down: Disconnect the power supply. Drain the liquid from the heat transfer oil pump, clean it, and regularly rotate the impeller 180 degrees to prevent shaft deformation, until the oil pump is completely cooled. 2. The heat transfer oil pump must be used with fuel of the appropriate grade. Generally, diesel grade 0 is used in summer, while -10 light diesel is used in winter. 3. The fuel used in the heat transfer oil pump must be clean, free of any impurities or moisture. 4. It is normal to have a slight leak at the beginning of operation of the heat transfer oil pump; after the sealing surfaces have been worn in for a certain period of time, the leakage will decrease or stop. Since the shaft of the heat transfer oil pump is equipped with a packing box at its front end, ensuring reliable sealing performance, and a mechanical seal is installed in the bearing housing, large-scale leaks are impossible; any minor leaks can be discharged and collected through the leak outlet. 5. The heat transferred from the medium being transported to the pump cover and bearings of the heat transfer oil pump is dissipated through the surfaces of the pump cover and bearing housings, thereby adjusting the temperature of the bearing housings to a level suitable for the shaft sealing performance. Therefore, when selecting the installation location for the heat transfer oil pump, it is necessary to ensure that the heat from the pump cover and bearing housing can dissipate easily, so that no heat accumulation occurs. 6. Two ball bearings are installed in the bearing housing; the ball bearing on the side of the pump impeller driven by the heat transfer oil pump is lubricated with the heat transfer oil being transported, while the ball bearing on the side of the coupling is lubricated with high-temperature grease. After 3000 hours of operation, each ball bearing must be removed, cleaned with diesel, and its contact surfaces checked for any damage. If damage is found, the bearing must be replaced. When installing the ball bearing on the impeller side, the side with the dust cover should face the impeller, and thermal oil should be poured in for lubrication before starting the machine. For the ball bearing on the side of the coupling, use a composite calcium-based high-temperature lubricant. When reinstalling this bearing, the side with the dust cover should also be oriented toward the impeller side, and lubricant should be filled during installation. After the bearing has been running for 48 hours, additional grease should be injected into the grease filling cup on the bearing cover using a grease gun. 7. Do not use the gate valve on the inlet pipe to adjust the flow rate, to avoid cavitation. 8. The heat transfer oil pump should not be operated continuously at a flow rate lower than 30% of its design flow rate. If operation under such conditions is necessary, a bypass pipe should be installed at the outlet to ensure that the flow rate remains above the aforementioned minimum value. 9. Regularly check whether the foundation bolts are loose, whether the temperature of the pump casing of the heat transfer oil pump matches the inlet temperature, the fluctuations in the outlet pressure gauge reading, and the vibration of the pump. 10. Pay attention to whether there are any abnormal noises during the operation of the heat transfer oil pump; if any abnormalities are detected, they should be addressed promptly.

A heat transfer oil pump is a regular hot oil pump; if it uses a dual-sealing system of mechanical seals and packing, the bearings at the end of the pump that are closer to it need to be lubricated with heat transfer oil. Additionally, the correct type of bearing must be selected, and considering high-temperature expansion, the clearance should be kept larger.

The heat transfer oil pump we used was originally lubricated with heat transfer oil, but it broke down within a few days. After replacing it with unlubricated oil (I forgot the grade), it performed well; although the usage time has not been very long, only about half a year, it is still much better than just a few days.

Based on practical experience with heat transfer oil pumps, it is best to use SKF bearings for the bearings. Considering high-temperature expansion, a larger clearance is necessary; bearings with a C4 clearance can be used

Please have the manufacturer provide clear oiling and maintenance guidelines; just follow those instructions