Oil-Free Air Compressor

Abstract

There is provided an oil-free air compressor that prevents oil from entering a compressor body by preventing a reverse rotation of the compressor body when the compressor is in shutdown, while improving the rust prevention effect, and that has improved reliability. An oil-free air compressor 100 includes an oil-free compressor body 1 that compresses air, and that outputs the compressed air; a cooler 5 that is connected to the compressor body, and that cools the compressed high-temperature air; a dry air supply mechanism for supplying dry air to an output side of the compressor body; and a mechanism for preventing a reverse rotation of the compressor body during a shutdown of the compressor.

1 . An oil-free air compressor comprising:
 an oil-free compressor body that compresses air, and that outputs the compressed air;   a cooler that is connected to the compressor body, and that cools the compressed high-temperature air;   a dry air supply mechanism for supplying dry air to an output side of the compressor body; and   a mechanism for preventing a reverse rotation of the compressor body during a shutdown of the compressor.   
     
     
         2 . The oil-free air compressor according to  claim 1 ,
 wherein the compressor body is an oil-free screw compressor.   
     
     
         3 . The oil-free air compressor according to  claim 1 ,
 wherein the mechanism for preventing the reverse rotation of the compressor body is a brake device.   
     
     
         4 . The oil-free air compressor according to  claim 1 ,
 wherein the mechanism for preventing the reverse rotation of the compressor body is a ratchet mechanism.   
     
     
         5 . The oil-free air compressor according to  claim 1 , further comprising:
 an oil pump that supplies lubricating oil to each bearing;   an opening-closing valve provided on a suction side of the oil pump; and   a single motor that drives the compressor body and the oil pump,   wherein the oil pump is a gear pump,   the motor, the compressor body, and the oil pump are connected to each other by gears, and   the opening-closing valve is closed during the shutdown of the compressor.   
     
     
         6 . The oil-free air compressor according to  claim 5 ,
 wherein the gear pump is a trochoid pump.   
     
     
         7 . The oil-free air compressor according to  claim 1 ,
 wherein, further, the dry air supply mechanism supplies the dry air to a suction side of the compressor body.   
     
     
         8 . The oil-free air compressor according to  claim 7 , further comprising:
 an unloader provided on the suction side of the compressor body and having a valve therein for throttling a path of the compressed air,   wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the compressor body.   
     
     
         9 . An oil-free air compressor comprising:
 an oil-free low-pressure stage compressor body and an oil-free high-pressure stage compressor body that compress air, and that output the compressed air;   an intermediate-stage pipe connecting the low-pressure stage compressor body and the high-pressure stage compressor body;   an intercooler that is provided in an intermediate stage, and that cools the compressed high-temperature air;   an aftercooler provided on an output side of the high-pressure stage compressor body;   a dry air supply mechanism for supplying dry air to the intermediate-stage pipe; and   a mechanism for preventing a reverse rotation of the low-pressure stage compressor body during a shutdown of the compressor.   
     
     
         10 . The oil-free air compressor according to  claim 9 ,
 wherein the low-pressure stage compressor body and the high-pressure stage compressor body are oil-free screw compressors.   
     
     
         11 . The oil-free air compressor according to  claim 9 ,
 wherein the mechanism for preventing the reverse rotation of the low-pressure stage compressor body is a brake device.   
     
     
         12 . The oil-free air compressor according to  claim 9 ,
 wherein the mechanism for preventing the reverse rotation of the low-pressure stage compressor body is a ratchet mechanism.   
     
     
         13 . The oil-free air compressor according to  claim 9 , further comprising:
 an oil pump that supplies lubricating oil to each bearing;   an opening-closing valve provided on a suction side of the oil pump; and   a single motor that drives the low-pressure stage compressor body, the high-pressure stage compressor body, and the oil pump,   wherein the oil pump is a gear pump,   the motor, the low-pressure stage compressor body, the high-pressure stage compressor body, and the oil pump are connected to each other by gears, and   the opening-closing valve is closed during the shutdown of the compressor.   
     
     
         14 . The oil-free air compressor according to  claim 9 ,
 wherein, further, the dry air supply mechanism supplies the dry air to a suction side of the low-pressure stage compressor body.   
     
     
         15 . The oil-free air compressor according to  claim 14 , further comprising:
 an unloader provided on the suction side of the low-pressure stage compressor body and having a valve therein for throttling a path of the compressed air,   wherein the dry air supply mechanism supplies the dry air to a pipe between the unloader and the low-pressure stage compressor body.