All operators carry out preventative maintenance routines to protect against unexpected failures, but if the worst does happen the repair needs to completed quickly and efficiently. For one blue chip company, Sulzer was able to get operations back up and running swiftly using the experienced, local service center in Leeds.
In this particular case, the operator of the compressor required more air pressure and unfortunately believed this could be achieved by closing the surge valve.
The consequence of this action was to cause the rotor to become unbalanced and hit the top diaphragm, resulting in damage to the impellers and all of the labyrinth seals.
The compressor was originally manufactured by Sulzer and the operator made two calls with a view to having the equipment repaired – one to the local service center and the other to an alternative original equipment manufacturer (OEM). Sulzer agreed to be on site immediately to inspect the damage and offer a proposal for the repair. With time being a crucial element in this project, Sulzer was contracted to complete the repair.
The initial inspection took place at the operator’s site and it was immediately apparent that of the three stages, number two had suffered catastrophic damage, along with the labyrinth seals. The decision was taken to transfer the complete compressor to the Leeds Service Center, where the turbomachinery repair service operation has recently relocated to, so that the repair process could begin.
As the local point of contact for the client, the Leeds Service Center coordinated the project and as it progressed, kept the client up-to-date with progress and timings. Projects involving complex equipment may need to involve the expertise of several service centers and it is essential that all aspects of a repair are carefully monitored to ensure that the client’s expectations are met.
The damaged rotor was sent to Sulzer’s Rotterdam Service Center, which is equipped with specialist facilities for remanufacturing rotors. Here, a new stage-two impeller was manufactured along with new labyrinth seals and sleeves, while the remaining impellers were refurbished. Meanwhile, a new diaphragm for stage two was manufactured and installed in the Leeds facility.
Dale Jarvis about the compressor repaired
Dale Jarvis, Business Development Engineer for turbomachinery at Sulzer’s Leeds Service Center, comments: “During the communications with the client, our engineers recommended that the bearings in the gearbox should also be checked for damage following the original failure. Since this drivetrain was already out of operation, the client agreed and the subsequent inspection highlighted a need to replace the bearings. By looking at the bigger picture we were able to deliver a more reliable solution without adding to the overall downtime of the project.”
Having completed the rebuild of the compressor, the field services team together with the client’s maintenance team reinstalled it, which completed the commissioning. In all, the repair was completed in 8 weeks, a time frame that had been agreed with the client at the start of the project; the refurbished compressor now has a significantly increased service life.
As a result of this project, further work will be carried out on similar compressor drivetrains in the same area, with special attention being paid to the gearbox bearings which may be reaching the end of their service lives.