Method for transferring coolant from a loading unit to an air conditioning system

Abstract

Method for transferring coolant fluid from a loading unit/station ( 20 ) to an air conditioning system ( 10 ), via at least one high pressure HP valve ( 7 ) and duct ( 15 ), for the introduction of liquid coolant, and at least one low pressure LP valve ( 8 ) and duct ( 17 ), for the suction and the recovery of the coolant-vapour in the system ( 10 ). It is provided for executing the step of transferring the fluid also maintaining the low pressure circuit branch ( 17 ) open/active, through relative LP valve. Part of the coolant loaded during the transfer step passes through a valve for the expansion of the system and it is suctioned, as vapour, by the station through LP: the net amount that enters into the system is always positive given that there is more loaded coolant with respect to the suctioned coolant.

1 . Method for transferring coolant fluid from a tank ( 11 ) of a loading unit/station ( 20 ) to an air conditioning system ( 10 ), said air conditioning station ( 20 ) comprising:
 a. a coolant tank ( 11 ),   b. a cut off valve ( 12 ) for opening and closing at least one duct ( 13 ) for the exit of coolant fluid,   c. a HP high pressure connection ( 14 ) connectable in a relative high pressure HP branch ( 15 ) to the air conditioning system ( 10 ), so as to be connected with a high pressure liquid coolant, or a fitting/valve ( 8 );   d. a LP low pressure connection ( 16 ) and which can be connected through a low pressure branch ( 17 ) to the air conditioning system ( 10 ), by means of a fitting/valve ( 7 ), arranged after an expansion valve ( 5 ) of the air conditioning system ( 10 );   e. a suctioning group ( 18 ) which, through compressor means, draws/extracts the coolant from the air conditioning system ( 10 ), through the low pressure branch ( 17 ), and takes it into the tank ( 11 ), by means of ducts ( 19 ), so as to empty the system;   the method comprising:
 transferring the fluid maintaining the low pressure circuit branch ( 17 ) open/active, through relative low pressure (LP) valve; the activation/opening of the low pressure LP branch which connects the air conditioning station to the LP valve of the air conditioning system, occurring at least partly simultaneously with the activation/opening of the high pressure HP branch which connects the air conditioning station to the HP valve of the air conditioning system; 
 passing part of the coolant loaded during said transferring through the valve ( 5 ) for the expansion of the system and suctioning it, as vapour, by the station through (LP) so that the net amount that enters into the system is always positive and more coolant is loaded with respect to the suctioned coolant, 
 recovering and re-introducing in the tank ( 11 ) the amount of coolant suctioned through LP, contributing to keeping loading pressure high, 
   the method further comprising:
 continuing the charge, without interruption, suctioning from the LP side and producing the evaporation of refrigerant in the system with consequent cooling and lowering of pressure, so that the system ( 10 ) is always at a lower pressure than that of the tank  11  of the loading station ( 20 ), 
 stopping the loading phase when a quantity QC of refrigerant loaded is greater than a nominal amount NA that is to be charged (namely the quantity that must be actually loaded), 
 continuing the recovering by the LP low pressure valve; during said recovering phase, measuring the quantity of refrigerant recovered and sent to the tank  11 , 
 continuing said recovering until said measured refrigerant is equal to the excess of refrigerant, namely QC minus NA.