| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an oil-free screw compressor achieving improved startup reliability. <P>SOLUTION: In the multi-stage oil-free screw compressor including: a suction throttle valve for controlling an intake amount into the compressor; a piston device for operating the suction throttle valve; and a structure for supplying a working pressure to the piston device, in order to reduce startup load at startup of the compressor, the suction throttle valve is fully closed while a secondary side of a compressor body is opened to the atmosphere. When a negative pressure and the atmospheric pressure, that provide the working pressure, are used for slightly opening the suction throttle valve in order to switch the compressor to a loaded mode after a motor for driving the compressor is accelerated to its top speed, the atmospheric pressure is provided by a control pipe line that is defined by the same pipe line that forms a drain pipe line. This permits the control pipe line to be opened to the atmosphere as needed during the startup time. Thus the oil-free screw compressor achieving improved startup reliability is provided. <P>COPYRIGHT: (C)2012,JPO&INPIT |
