Method for providing lubricant to thrust bearing

In a rotary screw compressor having a compressor housing with an inlet for flowing a gas to the compressor, a discharge port for flowing compressed gas and a lubricant from the compressor;

• a first rotor mounted on a first shaft;
• a second rotor mounted on a second shaft, said rotors and shafts being enclosed by the compressor housing;
• a first thrust bearing located along the first shaft;
• and a second thrust bearing located along the second shaft;
• a separator means for separating the lubricant and compressed gas said separator means having a sump portion and a sump discharge port, an apparatus for supplying the lubricant to the thrust bearings and compressor rotors, the apparatus comprising:
• a) first valve for controlling flow of lubricant to the apparatus;
• b) second valve connected to the discharge port of the sump of the separator means the second valve means for supplying lubricant from the sump to the rotors;
• c) temperature sensing means for sensing the temperature of the lubricant supplied to the rotors;
• d) pressure sensing means for measuring the pressure of the compressed gas discharged from the compressor;
• e) speed sensing means for detecting the operating speed of the rotors;
• f) electronic control means responsive to signals received from the temperature sensing means, the pressure sensing means and the speed sensing means for selectively opening and closing the second valve to optimize the volume of lubricant supplied to the compressor rotors, said control means also for controlling the first valve for controlling the flow of lubricant to the thrust bearings;
• g) pressure regulator means for controlling the supply of lubricant to the thrust bearings in response to input signals received from the electronic control means, said pressure regulator being flow connected to each thrust bearing by an independent lubricant supply line to thereby alter the pressure of each thrust bearing independent of the other thrust bearing.