A food products company used lubricated screw compressors to produce its compressed air for the plant. Due to tight budgets, the plant maintenance manager decided to stretch the maintenance intervals on the compressors as long as he could, but this led to unexpected disaster.
Within each lubricated screw compressor is an oil separator filter. This filter removed the compressor lubricant that is mixed with the compressed air as it exits the compressor screw element. Over time, this separator gets plugged up with dust and debris that is sucked into the compressor through the inlet filter.
As the separator becomes loaded, the pressure drop across it increases, causing higher than normal power consumption. Eventually, the increase in power will cause the compressor to trip off, but sometimes the separator element will suddenly fail, releasing most of the lubricant within the compressor to flow into the plant.
This is exactly what happened in the food processing plant. A slug of compressor lubricant was propelled down the line, ruining main line filters and contaminating air dryers and pipework. This resulted in a costly cleanup exercise, adding up to far more time and money wasted than the stretched maintenance intervals had saved.
Needless to say, the compressor maintenance frequency has now been adjusted back to normal.