Hitachi Industrial Equipment Systems Co., Ltd.

Ryusuke Oshiro

Hiroshi Ohta

Hideharu Tanaka

Hiroyuki Matsuda

Shigeyuki Yorikane

Akira Iyozumi

Tomoyuki Kado

Toshiyuki Toyonaga

Kazumasa Kanai

To prevent generation of drain reliably without depending on a difference in ambient temperature where a compressor is installed. Provided is a gas compressor: having a compressor main body compressing a gas, a drive source driving the compressor main body, a controller controlling the rotation speed of the drive source according to the discharge pressure of the compressor main body, and a temperature detector detecting the temperature of a discharge gas of the compressor main body; and performing no-load operation with the rotation speed of the drive source as a lower limit rotation speed when the discharge pressure reaches an upper limit pressure higher than a set pressure. When detecting that the temperature detected by the temperature detector is equal to or lower than a predetermined temperature during the no-load operation, the controller causes the lower limit rotation speed of the drive source to a lower limit rotation speed at which the temperature of the discharge gas is higher than the predetermined temperature and which is higher than a lower limit rotation speed when the detected temperature is higher than the predetermined temperature.

Gas compressor

To provide an air compressor capable of achieving energy saving. The air compressor is provided with a compressor body compressing air with injecting oil into a compression chamber; an air-pressure-operated intake throttle valve provided on an intake side of the compressor body; a separator provided on a delivery side of the compressor body and separating, from the compressed air delivered from the compressor body, a liquid contained in the compressed air; a compressed air system supplying the compressed air separated by the separator to a supply destination; an air release system connected to a primary side of a check valve in the compressed air system; an air-pressure-operated air release valve provided in the air release system; and an air-pressure operation circuit having a solenoid-operated three-way valve.

Air compressor

The invention is directed to reducing pressure-reduction time while preventing foaming in an oil-separation device during capacity control of a compressor, and to avoid startup congestion. This oil-supply-type compressor includes a main body, an oil-separation device, and an air-discharge passage for discharging compressed air during capacity control of the compressor. The air-discharge passage includes passages having large and small flow volumes, and when compressed air is discharged from the passage to the atmosphere during capacity control, the pressure in the oil-separation device is discharged using the large-flow-volume passage, until the pressure reaches or falls below a restarting-possible pressure, which is the pressure at which startup congestion does not occur when the compressor main body is restarted. When the pressure in the oil separation device reaches a prescribed pressure, which is less than or equal to the restarting-possible pressure and higher than a foaming pressure, the pressure is discharged using the small-flow-volume passage.

Oil supply type compressor

Growing community of inventors

Tokyo, Japan

Ryusuke Oshiro