Hitachi Industrial Equipment Systems Co., Ltd.

Akira Iyozumi

Hideharu Tanaka

Takashi Nakajima

Hiroshi Ohta

Hiroyuki Matsuda

Shigeyuki Yorikane

Kazumasa Kanai

Toshiyuki Toyonaga

Kenji Morita

Masahiko Takano

Masakazu Hase

Shinji Urata

Ryusuke Oshiro

Zhijia Ren

Yoshihiko Sagawa

Hayato Adachi

A communication control system for a number of gas compressors where one gas compressor is set as a master gas compressor that controls communication with N slave gas compressors. A cycle of communication with the N slave compressors in N communication sets is defined as a total compressor number communication cycle. In first to Nth communication sets, a first response request is transmitted to each of the first to Nth gas compressors. When a response is received from one of the gas compressors, the system determines that connection with the one gas compressor has succeeded. When no response is received, the system determines that connection has failed. In following communication cycles, a second response request is transmitted to the slave compressors with which communication has succeeded. The first response request is then transmitted to the slave compressors with which the communication connection has failed using a different timing sequence.

Gas compressor

A technique is provided that can further reduce power at the time of 'unload operation control' in a gas compressor that generates a compressed gas at a set pressure by constant-speed control. The gas compressor includes a compressor main unit, a drive source, an intake throttle valve, a gas release valve, rotation speed converting means, a pressure detecting device that detects a discharge pressure, and a controller that, the relationship between an upper-limit pressure H and a lower-limit pressure L being H&#x3e;L, carries out opening the intake throttle valve and closing the gas release valve and operating the drive source at a full-load rotation speed until the discharge pressure reaches the upper-limit pressure H. The controller carries out at least one of closing the intake throttle valve and opening the gas release valve to reduce the discharge pressure to within a predetermined range when the discharge pressure reaches the upper-limit pressure H. The controller carries out switching to load operation when the discharge pressure drops to the lower-limit pressure L. In the gas compressor, the controller outputs a command of a lower rotation speed than the full-load rotation speed to the rotation speed converting means when the discharge pressure rises and reaches the upper-limit pressure H. The controller outputs a command of the full-load rotation speed to the rotation speed converting means when the discharge pressure drops and reaches the lower-limit pressure L.

Control unit for air compressor with graphical user interface

Control unit for air compressor

Air compressor

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Tokyo, Japan

Akira Iyozumi