Combined Journal and Thrust Bearing Solve End Loading FailuresSeptember 24, 2010
One of the principal failure modes of Babbitt bearings is end loading. This occurs for several reasons:
- Journals are tapered when hot and in service, and when they trip out and run down, the tapered journal rubs against a bearing that was set for non-tapered journal, and wears the end of the bearing, often wiping the Babbitt.
- When sliding pedestals or standards slide and twist instead of sliding straight, or tilt due to broken grout, the bearings are no longer aligned to the journals, and the bearings wear or wipe, depending upon severity.
TRI provided a “Turnkey” Solution to this Problem.
Over the years, the overhung combined journal and thrust bearing of this steam turbine suffered repeated failures of the bearing which damaged the journal surface. It was known that the front standard tilted and slid irregularly, and that the soleplate was bowed. After trying the typical first solutions, without success, of improving the greasing of the standard, and then changing the loading on the bearing first higher loading and then lower loading, also without success, TRI was approached to resolve the problem. TRI’s engineering and experience rapidly developed this solution:
- Remove Standard and Soleplate
- Recondition the Sliding Surfaces
- Carefully Level and Regrout the Soleplate
- Reinstall the Sliding Standard
- Install a new Combined TRI Align-A-Pad® journal bearing and fully equalizing thrust bearing
TRI Consulting Engineering services designed the complete bearing for this application and directed the site activities during the outage, from how to support and lift the turbine shell prior to removing the standard and soleplate through start-up. TRI Shops built the Combined Journal and Thrust Bearing and performed the reconditioning work during the outage. Now many years have gone by with no more issues.