초록 ▼

A vapor compression refrigeration system is which a self heated thermistor is located in the suction line downstream of the evaporator to directly sense the quality of the refrigerant flowing thereover. Appropriate circuitry measures the voltage drop across the thermistor and this drop is used to va

A vapor compression refrigeration system is which a self heated thermistor is located in the suction line downstream of the evaporator to directly sense the quality of the refrigerant flowing thereover. Appropriate circuitry measures the voltage drop across the thermistor and this drop is used to vary the duty cycle of the system\s expansion valve thereby controlling the superheat of the evaporator.

대표청구항 ▼

A system for refrigerating or conditioning air in a compartment comprising: (a) pump means having an inlet and outlet and operative for compressing a charge of refrigerant gas and discharging the compressed gas at said outlet; (b) exothermic heat exchanger means connected for receiving a flow of sai

A system for refrigerating or conditioning air in a compartment comprising: (a) pump means having an inlet and outlet and operative for compressing a charge of refrigerant gas and discharging the compressed gas at said outlet; (b) exothermic heat exchanger means connected for receiving a flow of said compressed refrigerant from said pump means outlet and operative to cool and condense said gas to liquid; (c) expansion valve means connected for receiving said liquid at the inlet thereof and operative upon electrical energization to provide a pressure drop in said liquid refrigerant and to control flow thereof to the valve outlet; (d) endothermic heat exchanger means connected for receiving a flow of said liquid refrigerant from said expansion valve means outlet and operative to absorb sufficient heat from the compartment to be refrigerated or conditioned to heat said refrigerant and to cause said refrigerant to vaporize and including conduit means returning said vaporized refrigerant to the inlet of said pump means; (e) temperature sensing means including resistance means disposed to directly sense the temperature of said refrigerant discharging from said endothermic heat exchanger for returning to said pump inlet means; (f) means operative to provide a limited electrical current through said resistance means; (g) first circuit means operative to sense the voltage drop across said resistance means responsive to said current with said refrigerant flowing thereover and operative to determine the change in resistance thereof; (h) second circuit means operative in response to said change in resistance of said resistance means to generate an electrical pulse signal having the pulse time or width thereof corresponding to said resistance; (i) driver circuit means operative in response to receiving said pulse time signal to generate a periodic control signal having the ratio of “ON”time and “OFF”time in said period determined from said pulse time and a predetermined table of values, for a desired amount of superheat of refrigerant flowing over said temperature sensing means including means operative to apply said control signal to said expansion valve means for controlling refrigerant flow to modulate superheat about said desired value.