Temperature compensating refrigerant charging device

Claim 2

A temperature compensating refrigerant charging device comprising a volumetric refrigerant charging pump controlled by a temperature-responsive timer assembly comprising a thermistorcontrolled, pulser-actuated counter wherein the thermistor is in heat-transfer communication with the refrigerant the rate of pulsing of the pulser is responsive to the temperature induced changes in the resistance of the thermistor whereby an increase in the temperature of the refrigerant causes a reduction in the rate of pulsing and a decrease in the temperature of the refrigerant causes an increase in the rate of pulsing and wherein the counter counts the number of pulses of the pulser whereby a pre-determined setting of the counter allows the volumetRic pump to discharge a constant weight of the refrigerant by controlling the time interval of the operation of the pump in inverse proportion to the temperature-induced changes in the density of the refrigerant being pumped.

Claim 3

A device according to claim 1 wherein the counter is an adjustable digital counter in combination with a switch wherein the switch is closed when the counter has a reading other than zero, the counter upon actuation by the pulser counts down to zero at which point the switch opens, and said switch controls the electrical energization of the refrigerant charging pump.

Claim 4

A temperature compensating refrigerant device comprising a refrigerant supply reservoir, a charging gun for fluid transmitting connection to the high and low sides of a refrigeration unit and a fluid transmission system between said reservoir and said gun comprising a volumetric refrigerant charging pump and an electrical circuit for selectively energizing said charging pump which circuit comprises an adjustable counter switch, an electronic pulser in electrical association with the counter switch whereby the counter counts down in response to the pulses of the pulser, and a temperature-responsive resistor unit in heat transfer association with the refrigerant being pumped and electrically connected to said pulser whereby an increase in the temperature of the refrigerant decreases he rate of pulsing and the corresponding countdown of the counter and a decrease in temperature of the refrigerant increases the rate of pulsing and corresponding rate of countdown of the counter and wherein the counter switch opens when the counter has counted to zero, whereby for any pre-determined counter setting, a constant weight of refrigerant will be pumped not withstanding temperature-induced changes in the density of the refrigerant.

Claim 5

A temperature compensating refrigerant device comprising a refrigerant supply reservoir, a charging gun for fluid transmitting connection to the high and low sides of a refrigeration unit and a fluid transmission system between said reservoir and said gun comprising a volumetric refrigerant charging pump and an electrical circuit for selectively energizing said charging pump which circuit comprises an adjustable counter switch, an electronic pulser in electrical association with the counter switch whereby the counter counts down in response to the pulses of the pulser, and a temperature-responsive resistor unit in heat transfer association with the refrigerant being pumped and electrically connected to said pulser whereby an increase in the temperature of the refrigerant decreases he rate of pulsing and the corresponding countdown of the counter and a decrease in temperature of the refrigerant increases the rate of pulsing and corresponding rate of countdown of the counter and wherein the counter switch opens when the counter has counted to zero, whereby for any pre-determined counter setting, a constant weight of refrigerant will be pumped not withstanding temperature-induced changes in the density of the refrigerant.

Claim 6

A temperature compensating refrigerant device according to claim 3 wherein an electrical heating unit is in heat transfer communication with said refrigerant reservoir, said fluid transmission system includes pressure responsive means for preventing movement of the refrigerant from said reservoir towards said gun until the refrigerant, in response to said heating unit, has attained a pressure at which it will be in a liquid phase throughout said fluid transmission system.

Claim 7

A device according to claim 4 wherein a heat exchange unit is positioned in said system between said pressure responsive means and said charging pump.

Claim 8

A device according to claim 3 comprising as an additional system in communication with said charging gun a vacuum pump, a conduit connecting the low pressure part of said pump with said charging gun and connector means associating said pump with said electrical circuit for operating said vacuum pump at least during the initial connection of said gun to said refrigeration unit until the latter is evacuated.

Claim 9

A device according to claim 6 wherein said additional system includes valve means for maintaining the association between said vacuum pump and the high and low sides of said refrigeration unit until said charging pump commences operation and thereupon disassociating said vacuum pump from said refrigeration unit.