| 摘要 |
926,256. Valves. GENERAL MOTORS CORPORATION. Dec. 6, 1961 [Dec. 13, 1960], No. 43680/61. Class 135. [Also in Group XIII] In a refrigerator in which a compartment is cooled by air circulated past an evaporator and through the compartment, the rate of air flow is variable by a valve the position of which is controlled by an electric circuit which includes a thermo-responsive device located in the compartment. As shown, a duct 62 has a valve 64 to control the air flow therethrough, the valve being hinged by a bi-metallic strip 66, Fig. 2, controlled by a heater 78 so as to open the valve as the temperature of the heater rises. The valve is connected at one end to an adjustable arm assembly 68 which permits the initial opening of the valve to be set. Two thermistors 80, 82 are connected in parallel and situated as shown, are connected in series with the heater 78 so that as the temperature rises in the compartment their resistance decreases and results in an increase in the current flowing through the heater 78. An adjustable resistance may be placed in series with the heater to allow for further adjustments of the valve. In a modification the bi-metallic strip is selfheating and zig-zag in form. Further modifications involve the use of thermistors with positive temperature co-efficient of resistance, the use of more than two thermistors or the use of a tensioned wire through which the electric current passes in place of the bimetallic strip.
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