SUBMITTED BY: John H. Williams
TITLE: Vibration Analyst
EQUIPMENT: 700 HP Frick ammonia compressors.
TECHNOLOGIES APPLIED:
Vibration analysis and Ultrasound.
PROBLEM DESCRIPTION:
Vibration readings came into alarm on #6 Frick ammonia high stage compressor. Vibration readings taken on the outboard side of the male and female compressor screw bearings continued to rise. Readings went into alarm in April. Work order was written to repair compressor. Work was submitted for approval. Unit was shut down until work was completed.
INVESTIGATION:
Base line reading on male screw conveyor 12/14/2005
Readings into alarm on 4/14/2006
Readings after repairs 11/6/06
CONCLUSION: Compressor refurbished and bearings replaced. New readings were taken above. The unit was able to be repaired in place with significant costs savings versus sending compressor out for repairs. Problem was located before any damage happened to screws or compressor head. Bearings were found to have significant wear after 10 years of running time and poly metallic bearing cages had broken down. A spacer for the thrust bearings was found to be in backwards also.
Thrust Bearing Bearing Cage Gone
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IN SUMMARY:
When suspect readings show up, you can check bearings for cage failure by shutting down the compressor and turning machine coupling over by hand. Listen with mechanic’s stethoscope and you should hear the rollers hitting as the shaft turns over. The bearing cage is usually the first thing to fail on these compressors.
It’s much better to locate the problem now before catastrophic failure.
{ 1 comment… read it below or add one }
I would like to have opportunity to talk to your vibration specialist.
I have important information to share with them.
I can be reached at xxx xxx xxxx.
Luc Pellerin