The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 23, 2024

Filed:

Dec. 29, 2020
Applicant:

Hitachi Industrial Equipment Systems Co., Ltd., Tokyo, JP;

Inventors:

Tomoyuki Kado, Tokyo, JP;

Kentaro Yamamoto, Tokyo, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04C 28/28 (2006.01); F04C 18/16 (2006.01);
U.S. Cl.
CPC ...
F04C 28/28 (2013.01); F04C 18/16 (2013.01); F04C 2270/80 (2013.01); F04C 2270/90 (2013.01);
Abstract

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.


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