Hitachi Industrial Equipment Systems Co., Ltd.

Tomoyuki Kado

Kentaro Yamamoto

Yuki Taniyama

Ryusuke Oshiro

Norikazu Saitou

In the operation of a refueling screw compressor, when load conditions constantly fluctuate or when the rotation speed control of a cooling fan is performed, it is difficult to accurately perform a diagnosis predicted from measurement results of devices inside the compressor, so a diagnostic mode stably creates an operating condition under which an accurate diagnosis can be performed. In the refueling screw compressor, a discharge electric valve is provided downstream of an air cooler, and an air release electric valve and a dedicated orifice are provided to connect an oil separator inner space and a suction throttle valve space. In the diagnostic mode, the discharge electric valve is closed, the air release electric valve is opened, and while an upstream pressure of the oil separator is maintained at a specified pressure, a rotation speed control operation of a compressor body and the diagnosis of internal devices are performed.

Refueling screw compressor

A fluid machine that performs efficient cooling of a control system, such as a control device. The fluid machine is provided with: a fluid machine body; a drive source; a control device; a housing in which the fluid machine body, the drive source, and the control device are housed; and a cooling fan. The housing has a plurality of intake openings for introducing cooling air into the interior thereof and one exhaust opening, and includes a partition wall which partitions the interior of the housing into a first compartment and a second compartment and which has a communication portion providing communication between the first compartment and a part of the second compartment. A first intake opening among the plurality of intake openings is disposed in a housing wall of the first compartment in which at least the control device is disposed, and a second intake opening is disposed in a housing wall of the second compartment in which at least the drive source is disposed. The exhaust opening discharges the cooling air that has flowed from the first intake opening into the second compartment via the communication portion and that has cooled one of the fluid machine body and the drive source, and the cooling air that has been taken in via the second intake opening. A part of the control device is disposed facing an area of the first compartment downstream of the first intake opening and upstream of the communication portion.

Fluid machine

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.

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Tokyo, Japan

Tomoyuki Kado