What may be the probable reason of high temperature in slide shoe bearings of cement mill?

Question: What may be the probable reason of high temperature in slide shoe bearings of cement mill?

Reply: First thing to do is to check the position of the temperature sensor installed on the slide shoe. Second analyze the high/low pressure oil system. Look for manuals and see working range parameters for oil temp, oil pressure, initial high pump pressure, low pressure pump oil flow and speed, then observe those in operation. Once the mill is stopped for regular maintenance check with a portable thermometer the slide shoe from the outside, look for temperature highest point, look for temperature difference. Metal contact first come to mind. The root cause analysis might be tricky though. It might be high pump failure, you should see the development of pressure of the oil at the start up, if the max range pressure is reached or not. Pump failure for oil lack of cleanliness are frequent (you might control as well filters status here, or if the slide shoe bearing sealing is properly tight). Pumps just loose their prevalence and increase recirculation when damaged by dust, sand slowly. Go for over-sized pump, sturdy long life ones. Not having a proper sealing leave no choice to the cement or ground powder but to enter and clog your sys. Dust don't flow out easily, and rest in tanks forever. Make oil samples and analyze your results, looking for metal, especially the characteristic one made of your bearings. Consult the supplier of the bearing and ask for the limit in ppm when they should worrie about metal to metal contact. Contact the oil supplier and ask for chemical analysis of your oil, and ask them for limits as well, you will get a good insight of your system and oil quality though .Another way to check your sys, is to make sure during the start up the high pump are actually able to lift the mill (0.2-0.3 mm) before loosing pressure out of the slide shoes for increase of oil flow (use accurate tools which enable to measure this details. You can as well lift up your mill on a side, and observe the sliding parts, but indeed to do that in a proper and safe way you need some time, plus an expert to look at your bearings. It might also be that bearing shape is not properly done and oil doesn't flow around it. Check in this case the low pressure oil intake and outtake parts at shoe bearing boards, look for symmetric faces between them. Metal failure and lack of roughness are less frequent. You might check at the surface of yours, (with proper tools) in case you have the suggested metal roughness suggested by the bearing supplier with the right oil.