Method and apparatus for recovering the refrigerant from an air conditioning system

Abstract

An apparatus for recovering refrigerant ( 230 ) from an air conditioning system includes a collector for connecting hydraulically a high pressure branch and a low pressure branch, provided in the air conditioning system, with a fluid feeding duct of the fluid into the apparatus. The apparatus also has an evaporator arranged to separate the refrigerant from impurities, through an evaporation of residual liquid fractions of the refrigerant obtaining a purified refrigerant that rises towards an upper part of the evaporator, from impurities that are concentrated in a lower part of the evaporator.

1 . An apparatus for recovering a refrigerant from an air conditioning system, said apparatus comprising:
 a collector hydraulically connected to a high pressure branch and a low pressure branch of the air conditioning system with a fluid feeding duct in said apparatus;   an evaporator arranged to separate said refrigerant from impurities through an evaporation of residual liquid fractions of said refrigerant, in order to obtain a purified refrigerant that evaporates and rises towards an upper part of the evaporator, and to obtain impurities that are concentrated in a lower part of said evaporator;   a suction unit for circulating the purified refrigerant exiting from said evaporator, said suction unit being in hydraulic connection with said feeding duct through said evaporator, said suction unit comprising a compressor;   a condenser in hydraulic connection with said suction unit, said condenser arranged to condense the refrigerant exiting from said suction unit;   a storage container in hydraulic connection with said condenser, said storage container arranged to contain the refrigerant condensed by said condenser;   
       wherein upstream of said evaporator an auxiliary compressor means is provided arranged in parallel to said feeding duct, said auxiliary compressor means configured to boost the flow rate of said refrigerant towards said evaporator and for assisting a progressive pressure reduction of said refrigerant in said air conditioning system in cooperation with said suction unit. 
     
     
         2 . The apparatus according to  claim 1 , wherein said feeding duct comprises a first portion, downstream of said collector, and a second portion consecutive to said first portion and arranged upstream of said evaporator, and said auxiliary compressor means is arranged in parallel to said second portion, wherein in said second portion a feed valve is arranged movable between an open position and a closed position, so that, when the pressure in said first portion is higher than a threshold value, said auxiliary compressor means is turned off and said feed valve is in open position, and so that, when the pressure in said first portion is less than said value, said auxiliary compressor means is turned on and said feed valve is in closed position, so that the refrigerant is fed to said evaporator through said auxiliary compressor means, which cooperates with said suction unit for lowering further the pressure on said first portion of said feeding duct. 
     
     
         3 . The apparatus according to  claim 2 , wherein said auxiliary compressor means for lowering the pressure of said refrigerant on said first portion of said feeding duct comprises a vacuum generation device. 
     
     
         4 . The apparatus according to  claim 3 , wherein said vacuum generation device is connected hydraulically with said evaporator by a three-way valve, said three-way valve arranged to connect selectively said vacuum generation device with said evaporator, or with a purge duct, in order to cause said vacuum generation device to work selectively either as auxiliary compressor means or as purge means, for purging the refrigerant that cannot be regenerated and still residually present in said air conditioning system. 
     
     
         5 . The apparatus according to  claim 2 , wherein said auxiliary compressor means for reducing the pressure of said refrigerant on said first portion of said feeding duct comprises a dry-operating compressor, and wherein upstream of said dry-operating compressor a vacuum generation device is arranged to purge the refrigerant that cannot be regenerated from said apparatus for recovering refrigerant. 
     
     
         6 . A method for recovering and regenerating a refrigerant from an air conditioning system, said method comprising the steps of:
 feeding a refrigerant through a collector into a recovering and regenerating apparatus, said collector arranged to connect hydraulically a feeding duct of said apparatus with a high pressure branch and a low pressure branch of said air conditioning system;   evaporating residual liquid fractions of said refrigerant from an evaporator arranged to separate said refrigerant from impurities obtaining a purified refrigerant that evaporates rising towards an upper part of the evaporator and obtaining impurities that are concentrated in a lower part of said evaporator;   causing a suction and circulation of the refrigerant through the apparatus by a suction unit, said suction unit being in hydraulic connection with said feeding duct through said evaporator;   condensing the refrigerant exiting from said suction unit by a condenser in hydraulic connection with said suction unit;   accumulating refrigerant condensed by said condenser into a container in hydraulic connection with said condenser;   
       wherein said step of causing a suction and circulation of the refrigerant through the apparatus is carried out by said suction unit in combination with an auxiliary compressor means that operates upstream of said evaporator, and that increases the flow rate of said refrigerant towards said evaporator for assisting a reduction of the pressure of said refrigerant in said air conditioning system.