The temperature of the main thrust bearing of the steam turbine is high
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In one turbine, the temperature of a single bearing pad responsible for the main thrust (Mitchell type) is high (while the temperatures of the other bearings are normal); as the load increases, this bearing pad’s temperature also rises, reaching up to 105°C at its highest. During the disassembly and inspection of the thrust bearing, significant wear was observed on the oil return sides of both the main and auxiliary thrust pads. Maintenance and adjustment: 1. Check for any deviation of the thrust disc, ensuring that the contact surfaces between the thrust pads and the thrust disc meet the required standards. II. Increasing and decreasing the return oil flow to the thrust bearings, as well as increasing the axial play, did not result in any improvement during testing. I seek advice from experts – what’s the problem?
In this case, the possible reason is uneven stress on the thrust bearings themselves; it is recommended to check whether there are any differences in thickness among those bearings； Parallelism between the thrust pad and the balance disc ； Pin tightening force.
The thickness of the tiles was measured, and new tiles were also replaced. The contact surface between the tile and the thrust disc was also inspected. I agree with you regarding the uneven stress on the bricks, but I’m not sure how to deal with it
Check the end-face runout of the thrust disc; it should be less than 0.02 mm, and the wobble should be less than 0.03 mm. Ensure that the contact area is evenly distributed on each thrust pad.
Check the end-face runout of the thrust disc; it should be less than 0.02 mm, and the wobble should be less than 0.03 mm. Ensure that the contact area is evenly distributed on each thrust pad.
In my opinion, the key issue lies in the levelness of the device itself; it might be a good idea to check its levelness.
I also measured the shaft diameter camber value on the exhaust side of the turbine, and there is a slight deviation in the camber. To adjust the lift, one must move the device itself; otherwise, no adjustment is possible. But this doesn’t seem to be the main factor
Because such devices consist of multiple main units connected by couplings. It is still better to conduct a comprehensive inspection. Additionally, check whether the levelness you have measured corresponds to the axial force; if it does, adjustments need to be made.
You can check the reasons for the issue with the bracket, such as whether there are any errors in the parallelism of the base ring and the thrust plate!
Both the wear plates at the main and auxiliary return oil ports are worn; I have ground the contact areas, and they are in good condition. But in actual operation, it feels like the tiles are not subjected to even stress
First, the thickness of the compacts in the same group. Second, the thrust disc runout value. Third, the parallelism between the base ring and the thrust disc. Fourth, the contact area between the tile and the thrust disc. If we set aside those other factors, I think next time you could replace the tile holder, or remove those two tiles that are more worn out, and then measure the thrust clearance again to see if there is any difference from the original measurement values