EMS Inc. / Alberta / Canada / Case Studies / Cross-Head Bushing Failure Diagnoses

Cross-Head Bushing Failure Diagnoses

Unit: Gemini B452 Compressor – 600 Bhp Driver

Reciprocating Compressor Analysis data was taken from a machine that has been a long term candidate on a CdM program and is an example of one of the leading benefits of evaluating reciprocating machinery health with this type of data.  There were no indications of an issue prior to this diagnosis with all pressures and oil sample trends stable.  Data analysis showed a distinct change in vibration pattern over the samples and indicated a problem developing.  The analysis results were immediately communicated to the client and a service was performed to inspect the unit.

 There is no question that the resultant downtime would have been much greater and the extent of the damage much worse had the unit continued to run to a crash situation.  The piston rod and connecting rod assembly were re-used in this case with downtime minimized and planned.

The grey sample represents data from the previous analysis on throw #2 cross-head.  The red sample is data from the failure diagnoses and the blue sample is the post repair baseline data sample.

Reciprocating Compressor Analysis - Condition Monitoring - Cross head pin bushing
Cross Head pin bushing trend data.

By employing an experienced EMSi analyst and implementing regular condition monitoring intervals, this failure was caught prior to any incidental damage being caused other than the repair of the cross-head assembly itself.  This unit is on a regular PM program with oil analysis and does have standard vibration shutdown mechanisms installed.  The ability of having a trained analyst to decipher the data collected in this case was well in advance of any other types of regular PM program or vibration sensor technology to shut the unit down.  Planned downtime is far more cost effective than having crash maintenance performed.