초록 ▼

A refrigerant control system employing a “self-heated”thermistor disposed in the high pressure refrigerant line to sense refrigerant temperature from the condenser as it enters the expansion valve or capillary. The voltage drop is detected across a resistor in series with the thermistor and converte

A refrigerant control system employing a “self-heated”thermistor disposed in the high pressure refrigerant line to sense refrigerant temperature from the condenser as it enters the expansion valve or capillary. The voltage drop is detected across a resistor in series with the thermistor and converted to saturation pressure from known refrigerant properties. A microprocessor de-energizes the compressor and turns on the condenser fan when excessive saturation pressure is detected. An optional second thermistor senses actual refrigerant temperature for comparison with the saturation temperature to determine sub-cooling and the microprocessor disables the compressor in the event of excessive or insufficient sub-cooling.

대표청구항 ▼

A compressor cut-out and condensor fan cycling system for controlling refrigerant flow between an exothermic and an endothermic heat exchanger comprising: (a) pump means operable upon energization to compress said refrigerant and discharge same under pressure; (b) conduit means operatively connectin

A compressor cut-out and condensor fan cycling system for controlling refrigerant flow between an exothermic and an endothermic heat exchanger comprising: (a) pump means operable upon energization to compress said refrigerant and discharge same under pressure; (b) conduit means operatively connecting the discharge of said pump means through said exothermic heat exchanger and said endothermic heat exchanger and return to the intake of said pump means to said endothermic heat exchanger; (c) expansion means disposed in said conduit means and operative to control flow of refrigerant between said exothermic heat exchanger and said endothermic heat exchanger; (d) a saturation thermistor disposed in said conduit between said exothermic heat exchanger and said expansion means for sensing the temperature of said refrigerant on the high pressure side of said expansion means; (e) resistance means in series electrically with said thermistor; (f) circuit means operable to effect a flow of current through said resistance means and said thermistor sufficient for effecting boiling of said refrigerant on said thermistor and including means operable to detect the voltage drop across said resistance means upon said flow of current; (g) fan means operable upon electrical energization to direct a flow of coiling air over said exothermic heat exchanger; (h) controller means operable in response to said voltage detection to energize said fan means when said detected voltage is greater than a first predetermined level and operable to de-energize said pump means when said detected voltage is greater than a second predetermined level.