Coupling Failure & Alignment of Turbine/Compressor Case Study

Problem

KHE secured a contract to investigate the cause of repetitive coupling failures on a steam turbine/refrigeration compressor system. The machine experienced three failures in nine months.

Solution

KHE examined the system and found evidence of high piping loads and high angular misalignment in the vertical direction. Analysis showed the last coupling failure was due to angular misalignment of the machine on the turbine side, caused by high piping loads on the turbine. KHE performed pipe stress analysis and communicated with the turbine manufacturer for their input.

Results

The vibration levels were reduced from .24 in/sec to .17 in/sec. Due to operational difficulties with a portable refrigeration unit, the schedule of the project was greatly accelerated. However, the equipment returned to reliable service with the remainder of the changes scheduled for the next turnaround.