Oil feed type air compressor

An oil feed type air compressor comprising:

• a compressor main body that compresses air while injecting oil into a compression chamber;
• a separator that separates the oil from compressed air discharged from the compressor main body;
• and
• an oil feeding system that feeds the oil separated by the separator into the compression chamber of the compressor main body, wherein
• the oil feeding system includes an oil cooler that cools the oil, a bypass pipe that bypasses the oil cooler, and a temperature control valve that adjusts a diversion ratio for the oil cooler and a diversion ratio for the bypass pipe according to a temperature of the oil, and
• the oil feed type air compressor further includes
• a first pressure sensor that is located in the oil feeding system and senses a pressure of the oil,
• a second pressure sensor that is located on a downstream side of the first pressure sensor in the oil feeding system and senses a pressure of the oil,
• a temperature sensor that senses a temperature of the air on a discharge side or an intake side of the compressor main body, and
• a controller that computes, when it is estimated that the diversion ratio for the oil cooler is 100% and the diversion ratio for the bypass pipe is 0% from the temperature sensed by the temperature sensor exceeding a predetermined value, a difference between the pressure sensed by the first pressure sensor and the pressure sensed by the second pressure sensor and determines a deterioration state of the oil in reference to the difference.