Hitachi, Ltd.

Junji Okita

Seiji Tsuru

Shinichi Hirose

Katsuaki Kikuchi

Tadashi Kaneki

Akira Suzuki

Mitsuru Fujiwara

Kazuya Kanazaki

A screw compressor system comprises a plurality of screw compressors the capacity of each of which is controlled by repeating load operation and no-load operation. Using a timer output corresponding to compressed gas consumption in a demander including gas consumption equipments, a parent controller determines the number of compressors to be operated among the plurality of compressors. Among the compressors determined to be operated, all compressors other than one are put in load operation. In accordance with a load factor of the excepted one screw compressor, the parent controller controls discharge pressure of each compressor. At this time, the control is made so that discharge pressure of the screw compressor system measured by a pressure gauge be lower than that upon the maximum gas consumption.

Screw compressor system and operating method thereof

Compressor bodies, an accelerator and a main motor are disposed on a base, while an innercooler, an aftercooler an oil cooler and a coolant cooler are disposed perpendicular to the axial direction of the motor so that the directions, in which the tube nests of the gas coolers are drawn out, are made to be the same. A control panel having a maintenance display is mounted on a front panel composed of panel portions which are mounted pivotally around respective remote or opposite side ends. Portions to be inspected daily are disposed near the front panel and one side panel adjacent thereto.

Package-type screw compressor

Compressor bodies, an accelerator and a main motor are disposed on a base, while an intercooler, an aftercooler, an oil cooler and a coolant cooler are disposed perpendicular to the axial direction of the motor so that the directions, in which the tube nests of the gas coolers are drawn out, are made to be the same. A control panel having a maintenance display is mounted on a front panel composed of panel portions which are mounted pivotally around respective remote or opposite side ends. Portions to be inspected daily are disposed near the front panel and one side panel adjacent thereto. The compressor bodies including rotors that have been coated with a melted and solidified substantially homogeneous and continuous layer of a tetrafluoroethylene-perfluoroalkylvinylether copolymer that is substantially devoid of pinholes.

Package-type screw compressor having coated rotors

In the screw compressing apparatus, by rotating paired male and female rotors as meshing with each other, a gas is suctioned from a suction chamber into a working space, and compressed in the working space. The compressed high pressure gas is exhausted from a exhaust chamber, and then cooled by an aftercooler, thereby producing a low temperature, high pressure gas. In the compression process, the temperature of the gas in the working space becomes high at the exhaust chamber side. When this exhaust gas temperature reaches a predetermined value, a part of the gas cooled by an aftercooler is injected into the working space for lowering the temperture in the working space.

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Ishioka, Japan

Junji Okita