Oil flow protection scheme

An oil protection system for a compressor comprising:

• a compressor operable to compress a compressible fluid and having a discharge, a rotor and a bearing;
• an oil supply system including a first oil line operably connected to and providing lubricant to the rotor and a second oil line operably connected to and providing lubricant to the bearing;
• an orifice located in either of the first or second oil lines and controlling flow therethrough;
• a first sensor located in the discharge so as to measure a condition representative of the temperature of the compressible fluid discharged by the compressor and provide a representative signal to the controller;
• a second sensor located proximal the orifice so as to measure a differential pressure across the orifice and provide a representative signal to the controller;
• a third sensor located proximal the oil line lacking the orifice, the third sensor measuring the presence or absence of liquid and providing a representative binary signal to the controller;
• and
• a controller operably connected to and receiving the signals from the first, second, and third sensors and operable to control the operation of the compressor and in response thereto, the controller using the first sensor signal to determine the quality of lubricating fluid, the second sensor signal to verify actual flow of the lubricating fluid, and the third sensor signal to distinguish between a liquid state of the lubricant and a vaporous state of the compressible fluid.

A method of protecting a compressor lubrication system comprising the steps of:

• sensing differential pressure in a compressor lubrication line to verify lubricant flow;
• sensing the discharge temperature of the compressor to verify lubricant concentration;
• and
• sensing the level of foaminess in a lubrication feed line to the compressor to verify lubricant quality.