Patent ID: 9568001
Date: 2017-02-14
CPC Classifications: F04C,F16J

Claim:
1. An oil-cooled screw compressor system comprising: an oil-cooled screw compressor; a tooth surface lubricating fluid supply system that supplies a tooth surface lubricating fluid to the oil-cooled screw compressor; a bearing lubricating fluid supply system that supplies a bearing lubricating fluid to the oil-cooled screw compressor, in addition to the tooth surface lubricating fluid; and a separation gas supply system that supplies separation gas different from target gas compressed by the oil-cooled screw compressor to the oil-cooled screw compressor, wherein the oil-cooled screw compressor includes: a housing in which a screw chamber, discharge side seal chambers connected to one end of the screw chamber, intake side seal chambers connected to the other end of the screw chamber, bearing chambers in communication with the screw chamber via either the discharge side seal chambers or the intake side seal chambers, respectively, a tooth surface lubricating fluid flow path through which the tooth surface lubricating fluid is supplied to the screw chamber, and a bearing lubricating fluid flow path through which the bearing lubricating fluid is supplied to the bearing chambers, are defined; male and female screw rotors each including: a screw that is disposed in the screw chamber and forms a compression chamber; and shafts that coaxially extend from both ends of the screw to be disposed in the discharge side seal chambers and intake side seal chambers and the bearing chambers; a plurality of bearings that are disposed in the bearing chambers, and rotatably support the respective shafts; and seal devices that are disposed in each of the discharge side seal chambers and the intake side seal chambers, and each seal a circumference of a corresponding one of the shafts, wherein the discharge side seal chambers are positioned on a discharge side of the compression chamber, and the intake side seal chambers are positioned on an intake side of the compression chamber, the seal devices each include: a first seal unit that is disposed on a side of the screw chamber in each of the discharge side seal chambers and the intake side seal chambers; and a second seal unit that is disposed on a side of the bearing unit in each of the discharge side seal chambers and the intake side seal chambers, the second seal unit and the first seal unit defining a separation gas supply gap therebetween, in the housing, a separation gas supply path through which the separation gas is supplied into the separation gas supply gap, and a pressure balancing path through which an area closer to the screw chamber than the first seal unit in the discharge side seal chamber is in communication with the compression chamber under a pressure higher than an inlet pressure of the target gas sucked into the oil-cooled screw compressor and lower than a discharge pressure of the target gas discharged from the oil-cooled screw compressor, are defined in addition to the tooth surface lubricating fluid flow path and the bearing lubricating fluid flow path, and a check valve that restricts a flow of a fluid in a direction from the screw chamber to the discharge side seal chamber is disposed in the pressure balancing path.