Gas Compressor

Abstract

A bearing oil feeding amount is appropriately controlled with respect to specifications of a discharge pressure (bearing load) and a rotation speed. A gas compressor has: a compressor main body that compresses gas and has a rotor; a bearing for supporting the rotor onto a compressor main body casing; an oil case that stores a lubricating oil to be supplied to the bearing; a lubricating oil pipe through which the lubricating oil is circulated from the oil case to the bearing; an oil pump that pumps the lubricating oil from the oil case to the bearing via the lubricating oil pipe; a flow amount control means for adjusting an amount of lubricating oil that circulates through the lubricating oil pipe; an electric motor that supplies power to the rotor; an inverter that outputs a rotation frequency of the electric motor; a pressure sensor that detects the discharge pressure of the compressor main body; and a control unit that determines a lubricating oil supply amount to the bearing on the basis of the load on the bearing corresponding to the pressure detected by the pressure sensor and the rotation speed of the rotor corresponding to the rotation frequency output by the inverter, and that controls the flow amount control means on the basis of the lubricating oil supply amount.

1 . A gas compressor comprising:
 a compressor main body having a rotor configured to compress gas;   a bearing configured to support the rotor on a compressor main body casing;   a storage part in which lubricating oil to be supplied to the bearing is stored;   a lubricating oil pipe through which lubricating oil flows from an oil case to the bearing;   an oil pump configured to pump lubricating oil from the oil case to the bearing through the lubricating oil pipe;   flow amount control means configured to adjust an amount of lubricating oil flowing through the lubricating oil pipe;   an electric motor configured to supply power to the rotor;   an inverter configured to output electric power of a predetermined rotation frequency to the electric motor;   a pressure sensor configured to detect a discharge pressure of the compressor main body; and   a control unit configured to control a low-pressure high-flow operation in which a rotation speed of the electric motor is increased with the same power consumption of the electric motor as when discharged gas of a specific pressure and a specific flow is produced, and discharged gas of a pressure lower than the specific pressure and a flow higher than the specific flow is discharged by the compressor main body;   the control unit   determines an amount of lubricating oil to be supplied to the bearing from a load on the bearing corresponding to the pressure detected by the pressure sensor and a rotation speed of the rotor corresponding to the rotation frequency of electric power output by the inverter, and controls the flow amount control means on the basis of the amount of lubricating oil to be supplied, and   determines the amount of lubricating oil to be supplied to the bearing from a load on the bearing corresponding to the specific pressure and the rotation speed of the rotor corresponding to the increased rotation speed, and controls the flow amount control means on the basis of the amount of lubricating oil to be supplied during the low-pressure high-flow operation.   
     
     
         2 . The gas compressor according to  claim 1 , further comprising an oil drain pipe through which lubricating oil returns from the lubricating oil pipe to the storage part, wherein
 the flow amount control means is a two-way solenoid valve, and   the two-way solenoid valve is disposed on the oil drain pipe.   
     
     
         3 . The gas compressor according to  claim 2 , wherein the oil pump is driven by power from the electric motor. 
     
     
         4 . The gas compressor according to  claim 1 , wherein the oil pump is driven by another electric motor different from the electric motor. 
     
     
         5 . The gas compressor according to  claim 1 , wherein
 the control unit stores in advance a correspondence table of the amount of lubricating oil to be supplied to the bearing associated with the load on the bearing corresponding to a pressure of compressed gas discharged by the compressor main body and the rotation speed of the bearing corresponding to the rotation frequency output by the inverter, and   with reference to the correspondence table, the control unit controls the flow amount control means on the basis of the amount of lubricating oil corresponding to an input value of at least one of the pressure detected by the pressure sensor and the rotation frequency output by the inverter.