Service unit for vehicle air-conditioning systems and method for removing the coolant or a coolant/compressor oil mixture from a vehicle air-conditioning system

Abstract

The invention relates to a service unit for vehicle air-conditioning systems, which is provided with an emptying and filling device for removing the coolant or a coolant/compressor oil mixture from a vehicle air-conditioning system and replenishing the vehicle air-conditioning system with coolant and optionally with compressor oil. The device can include at least one tank for coolant and a vacuum pump for generating a negative pressure in the vehicle air-conditioning system emptied of coolant or coolant/compressor oil mixture for a subsequent intake of coolant and optionally compressor oil into the vehicle air-conditioning system to be replenished. A chimney-like gas-collecting chamber having upper and lower openings can be arranged inside the service unit and is otherwise sealed off from the surrounding atmosphere.

1 . A service unit for vehicle air-conditioning systems,
 having a drainage device and a filling device for removing the coolant or a coolant/compressor oil mixture from a vehicle air-conditioning system and for refilling the vehicle air-conditioning system with coolant and where necessary with compressor oil,   having at least one tank ( 126 ) for coolant and   having a vacuum pump ( 132 ) for producing an underpressure in the vehicle air-conditioning system which has been drained of coolant or coolant/compressor oil mixture for a subsequent extraction of coolant and where necessary compressor oil in the vehicle air-conditioning system to be refilled,   characterised in that   a chimney-like gas collection chamber ( 110 ) having upper and lower openings ( 110 A,  110 B) is arranged inside the service unit ( 100 ) and is otherwise sealed off from the ambient atmosphere, and   an active fan ( 120 ) is provided for the flow of ambient air through the chimney-like gas collection chamber ( 110 ) from top to bottom.   
     
     
         2 . The service unit according to  claim 1 , characterised in that at least the unit parts of the active fan ( 120 ) and/or any additional active fans to which electrical voltage is applied and/or the control system thereof are arranged outside or on the outer side of the service unit. 
     
     
         3 . The service unit according to  claim 1 , characterised by an additional active fan ( 134 ) for loading a vacuum pump ( 132 ) arranged inside the chimney-like gas collection chamber ( 110 ) with ambient air. 
     
     
         4 . The service unit according to  claim 1 , characterised in that at least one, in particular a customary, vacuum pump ( 132 ) is used in the air-conditioning service unit, in which the electrical unit part of the vacuum pump ( 132 ) comes into contact with the gas to be evacuated. 
     
     
         5 . The service unit according to  claim 1 , characterised by an additional active fan ( 136 ) for loading a condenser ( 130 ) arranged inside the chimney-like gas collection chamber ( 110 ) with ambient air. 
     
     
         6 . The service unit according to  claim 1 , characterised in that the air streams of all the active fans can be conducted as an aggregate air stream ( 140 ) via a bottom exit opening ( 110 B) of the chimney-like gas collection chamber ( 110 ). 
     
     
         7 . The service unit according to  claim 1 , characterised in that additional storage tanks ( 124 A,  124 B,  124 C) of the service unit are sealed off fluidically from the chimney-like gas collection chamber ( 110 ) by at least one sealing wall ( 118 ). 
     
     
         8 . The service unit according to  claim 1 , characterised in that in particular all the regions of the service unit which come or can come into contact with the gas of the coolant systematically or owing to leakages are or can be fluid-connected to the chimney-like gas collection chamber and shut off from the remaining ambient atmosphere. 
     
     
         9 . The service unit according to  claim 1 , characterised in that any further fans, the electric motor of any vacuum pump and/or a compressor are preferably connected in such a manner that they can generally only start up if the downward air stream in the chimney-like gas collection chamber  110  is active. 
     
     
         10 . A method for removing the coolant or a coolant/compressor oil mixture from a vehicle air-conditioning system and for refilling the vehicle air-conditioning system with coolant and where necessary with compressor oil by means of a service unit having at least one tank for coolant and having a vacuum pump for producing an underpressure in the vehicle air-conditioning system which has been drained of coolant or coolant/compressor oil mixture for subsequent extraction of coolant and where necessary of compressor oil into the vehicle air-conditioning system to be refilled,
 characterised in that   a chimney-like gas collection chamber having upper and lower openings is provided inside the service unit and is shut off from the remaining ambient atmosphere, and   ambient air flows through the chimney-like gas collection chamber from top to bottom, in particular by means of at least one active fan.   
     
     
         11 . The method according to  claim 10 , characterised in that the at least one active fan for the chimney-like gas collection chamber remains switched off during stoppage phases or phases in which the service unit is not used, and the gases are left to sink downwards inside the chimney-like gas collection chamber, so that they exit the chimney-like gas collection chamber through the lower opening towards the ambient atmosphere. 
     
     
         12 . The method according to  claim 10 , comprising a separation step for coolant/compressor oil mixture, characterised in that residues are drained from the coolant circuit system of the vehicle air-conditioning system by means of a vacuum pump, and the coolant circuit system is fluid-connected to a separation stage for coolant/compressor oil mixture via the vacuum pump for the purpose of recovering coolant from the residue drainage of the coolant circuit system.