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.
Patent No.:
Date of Patent:
Oct. 08, 2002
Filed:
Mar. 02, 2001
Roy M. Yabuki, Arlington, TX (US);
Derek Y. Kamemoto, Seattle, WA (US);
Virender Jain, Lake Forest, CA (US);
Richard L. Kenyon, Irvine, CA (US);
Parker-Hannifin Corporation, Cleveland, OH (US);
Abstract
Apparatus for detecting low charge of a working fluid in a heat transfer system of the type having a fluid circuit comprising a compressor for pressurizing working fluid received from an evaporator, a condenser and condenser fan for cooling the working fluid received from the compressor, and an expansion device for controlling flow of the working fluid between the condenser and the evaporator, the apparatus comprising: a working fluid state sensor operative in response to a control signal and disposed in the fluid circuit on the outlet side of the evaporator to produce a working fluid state signal; and a control circuit for providing the control signal to the sensor and for controlling operation of the heat transfer system based on a comparison of the working fluid state signal with a state set point; the control circuit detecting a low charge condition of the working fluid when the state signal indicates the working fluid superheat exceeds a first predetermined threshold over a first predetermined time with the expansion device in a fully open condition.