Hitachi Industrial Equipment Systems Co., Ltd.

Yuuji Itou

Toshiaki Yabe

Tomoo Suzuki

Kohei Sakai

Takashi Nakajima

Hiroshi Horiuchi

Masayuki Kasahara

Kazumasa Kanai

Yuki Ishizuka

Provided is an air compressor that suppresses a rise in delivery temperature due to a change in atmospheric pressure, and consequently improves the life of parts. The air compressorincludes a motor, a compressor main bodydriven by the motorto compress air, a delivery pressure sensorthat senses a delivery pressure of the compressor main body, an atmospheric pressure sensorthat senses an atmospheric pressure, and a controller. The controllercompares the delivery pressure sensed by the delivery pressure sensorwith a set pressure, and performs operation control based on a result of the comparison. The controllercorrects the set pressure such that a ratio between the atmospheric pressure sensed by the atmospheric pressure sensorand the set pressure becomes a set value set in advance.

Air compressor

Compressor

In order to reduce operation in a rotation-prohibited frequency range and to prevent resonance in a gas compressor wherein inverter control is performed, this gas compressor has: a compressor main body that compresses a gas; a motor that rotationally drives the compressor main body; an inverter that changes the rotational speed of the motor; a check valve arranged downstream from the compressor main body; a pressure detection means that detects load-side pressure downstream from the check valve; and a control device that, in accordance with the pressure detected by the pressure detection means, controls the frequency output by the inverter. The control device performs a control whereby compressed gas having a prescribed pressure is generated/maintained by increasing/decreasing the frequency, and when the frequency that generates the compressed gas having the prescribed pressure includes a specific frequency, the inverter's output frequency is increased or decreased when the pressure detected by the pressure detection means reaches a pressure corresponding to a frequency that has a more constant pressure width than the prescribed pressure and does not include the specific frequency.

Gas compressor

A screw rotor which is hollow has improved performance against heat, pressure, rust, and the like. A screw rotor includes a screw portion of which an outer periphery has teeth and grooves having a helical shape and extending by a predetermined length in an axial direction. A radial cross section of at least a part of the screw portion includes a cross section of an outer surface portion forming the teeth and the grooves, a cross section of an axial center portion, a cross section of a support portion that connects an axial center side of the outer surface portion and an outer diameter side of the axial center portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial center side inner surface of a tooth bottom or a tooth tip. In at least the radial cross section of the screw portion, different members are continuously joined as an integral structure in a cross section of at least one of the axial center portion and the support portion and the outer surface portion.

Screw rotor and screw-type fluid machine main body

The invention prevents a decrease in strength of a screw rotor including a hollow portion and improves cooling performance. There is provided a screw rotor having a helical tooth on an outer periphery, the helical tooth extending by a predetermined length in an axial direction, in which a radial cross section of the screw rotor includes a cross section of a tooth portion, a cross section of an axial portion, a cross section of a support portion connected to an axial side of a tooth bottom or a tooth tip in the cross section of the tooth portion and an outer diameter side of the axial portion, and a cross section of a hollow portion formed by the support portions adjacent to each other in a rotational direction and an axial side inner surface of the tooth bottom or the tooth tip, and an axial longitudinal cross section of the screw rotor is a cross section in which the axial portion, the support portion, the axial side of the tooth bottom or the tooth tip, and an axial end portion of the screw rotor are continuously connected to each other as an integral structure by a three-dimensional fabrication method or the like.

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Tokyo, Japan

Yuuji Itou