Why is the drive end bearing temperature of the cantilever pump very high?
Thread Content
The on-site machine pump is a single-stage cantilever pump, and the pump type is a sunken-drum petrochemical pump ZHA50-4450. There are two 7312BECB bearings on the driving end and one NU312EC bearing on the non-drive end. The medium is crude gasoline at 40°C, the pump inlet pressure is 0.17MPa, and the outlet pressure is 1.85MPa. Adopt oil mist lubrication + wet oil bath lubrication. Fault phenomenon: The temperature outside the drive end bearing box exceeds 70°C, and the temperature of the non-drive end bearing is 43°C. (Oil mist lubrication and bearing box lubricating oil levels are normal, and the bearings are not faulty) Relevant processing has been done: 1. Recalibration center, no improvement ； 2. Adjust the axial clearance between the drive end bearing gland and the bearing to 15 degrees. The operating temperature drops from 70°C to 65°C. Although there is an improvement, the temperature is still high (generally the temperature is 45-50°C). At this time, the ambient temperature is about 28°C. question: Please analyze the reasons for the high temperature of the drive end bearing and how to deal with it. Please provide a detailed solution?
Check whether there are reinforcement ribs on the back of the impeller or whether other gaps exceed the standard. Large axial force will cause this problem.
It is recommended to test the levelness of the equipment. In terms of process, check the density, pressure, flow temperature, etc. of the medium to see if it meets the conditions for use of the equipment.
Can't oil mist lubrication be used alone?
At the beginning, it was pure oil mist lubrication, and the temperature was also out of standard. After consulting the manufacturer, the device was changed to dry + wet lubrication. Although the situation improved, the temperature was still out of standard as mentioned above.
Bearing temperature is high and vibration is large?
Are the 7312 bearings installed back-to-back or face-to-face? How much is the bearing clearance adjustment after combined installation?
It is the axial force problem. It is recommended to consider whether the impeller has a balance hole and its hole diameter from the design aspect.
You can also consider using angular contact bearings with small contact angles such as the A series.