Oil free screw compressor

Number of patents in Portfolio can not be more than 2000

United States of America Patent

PATENT NO 8651839
APP PUB NO 20120164017A1
SERIAL NO

13192592

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Importance

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Abstract

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A multi-stage oil-free screw compressor includes: a suction throttle valve for controlling air intake into the compressor; a piston assembly for operating the suction throttle valve; and a structure for supplying a working pressure to the piston assembly. In order to reduce startup load at the time of 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 air 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 air 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 is provided the oil-free screw compressor achieving improved startup reliability.

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First Claim

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Patent Owner(s)

  • HITACHI INDUSTRIAL EQUIPMENT SYSTEMS CO., LTD.

International Classification(s)

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Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Fujimoto, Hideki Shizuoka, JP 73 655
Nishimura, Hitoshi Shizuoka, JP 84 875

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