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:
Sep. 25, 2001
Filed:
May. 31, 2000
Derek Y. Kamemoto, Seattle, WA (US);
Red Dot Corporation, Seattle, WA (US);
Abstract
Apparatus for monitoring a refrigerant state in a refrigeration system includes a charge sensor and a controller. The sensor is positioned adjacent to the outlet of an evaporator. The sensor produces a voltage output signal in response to an input signal from the controller. The controller compares the output signal to a predetermined set point chosen to correspond to a predetermined refrigerant state. The sensor is preferably a self-heated thermistor positioned adjacent to flow exiting the evaporator through the outlet. The controller preferably compares the output signal to a set point at preset intervals and computes an average for a predetermined time duration. This helps to avoid false readings due to transitory conditions. The apparatus may be used in various types of refrigeration systems but is contemplated to be used primarily in mobile air conditioning systems in order to detect a reduced refrigerant charge in such systems. In such applications, the input signal is preferably an at least substantially constant voltage applied to a voltage divider circuit. Input from elements in addition to the charge sensor may be used to enhance the accuracy of detection.