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:
Jun. 15, 1976
Filed:
Nov. 25, 1974
Richard E Widdowson, Dayton, OH (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A piloted refrigerant valve for an air conditioning system to control refrigerant pressure within an evaporator to prevent frost accumulation on its exterior surfaces. The valve includes a disc-shaped hollow thermal sensor filled with water which solidifies and expands upon sensing the freezing temperature to cause a pilot valve to block a bleed port and thereby increase the fluid pressure above a reciprocally mounted piston valve. The pressure force produced on the piston valve moves it to a closed position to block refrigerant flow and resultantly to increase refrigerant pressure and temperature in the evaporator. After an initial start-up period of operation, the sensor maintains a position which locates the reciprocal piston valve so as to produce a substantially constant non-freezing temperature of refrigerant in the evaporator.