Patent ID: 6016661
Filing Date: 2000-01-25
Classification: F25B

Abstract:
A refrigerant recovery system for use in combination with a low pressure recovery reservoir to recover refrigerant from an evaporator and a condenser selectively operable in a plurality of system operating modes including a pressurized mode, a liquid refrigerant recovery mode and a vapor refrigerant recovery mode comprising a system control including a microprocessor to control the operation of the refrigerant recovery system and a plurality of control sensors to monitor a corresponding plurality of system operating parameters, a refrigerant processor operatively coupled to the low pressure recovery tank and the evaporator and the condenser by a fluid flow conduit network including a plurality of fluid conduit branches and a fluid flow control including a plurality of fluid flow control devices coupled to said microprocessor to receive control signals therefrom and operatively disposed relative to said fluid conduit network to selectively configure said fluid conduit network to control the flow of the refrigerant therethrough in a plurality of operating configurations corresponding to said plurality of system operating modes in response to the state of said plurality of system operating parameters sensed by said plurality of control sensors to transfer refrigerant from the evaporator and the condenser to the low pressure recovery reservoir, the low pressure recovery reservoir comprises a recovery tank including a liquid refrigerant recovery flow control device and a vapor refrigerant recovery flow control device to selectively control the flow of refrigerant therethrough, the evaporator includes a liquid refrigerant flow control device to selectively control the flow of refrigerant therethrough and the condenser includes a vapor refrigerant flow control device to selectively control the flow of refrigerant therethrough and said refrigerant recovery system being coupled between the evaporator and the condenser and the low pressure recovery reservoir by a plurality of vapor and liquid hoses said plurality of system sensors including a pressure sensor to monitor the pressure within the evaporator and to generate an evaporator pressure signal in response thereto fed to said microprocessor and a recovery pressure sensor to monitor the pressure within the recovery tank and to generate a recovery tank pressure signal in response thereto fed to said microprocessor, said microprocessor including logic means to compare the evaporator pressure with the recovery tank pressure and to generate system control signals in response thereto whereby refrigerant distribution will begin to equalize throughout said refrigerant recovery system and flow toward the recovery tank and after a first predetermined period of time of equalization, said microprocessor sends control signals to said fluid flow control devices to circulate refrigerant from the recovery tank of the low pressure recovery reservoir through said refrigerant processor to the condenser and evaporator causing the pressure in the recovery tank to decrease and the pressure in the evaporator and the condenser to increase, said refrigerant recovery system will continue to operate in the pressurization mode until a predetermined pressure differential between the recovery tank and said condenser is created, when said predetermined pressure differential is created between the evaporator and the recovery tank said microprocessor reconfigures said refrigerant recovery system from said pressurization mode to said liquid refrigerant recovery mode where liquid refrigerant travels from the evaporator through said fluid conduit network into the recovery tank where the liquid is transferred from the evaporator to the recovery tank, said microprocessor will reconfigure said refrigerant recovery system into said vapor recovery configuration when the liquid refrigerant is transferred from the evaporator to the recovery tank for operation in said vapor recovery mode where vapor is drawn from the condenser through said fluid conduit network through said refrigerant processor to condense the refrigerant and thence through said fluid conduit network to the recovery tank the vapor refrigerant recovery is completed.