a valve guide bar 30 which is received in a hole 31 of the evaporator housing 32 in such a way that it can perform lifting movements the top side 33 of the valve plate 29 is pressed by means of a valve spring 34 against a sealing crater 35 of the filling valve 28 a guide ring 36 is connected with the valve plate 29 and can be displaced together with the valve plate 29 the filling system according to the present invention operates as follows when the bottle adapter 1 is plugged into the filling device 20 the o ring 6 first slides over the lead in bevel 24 and is in contact with the sealing surface 23 of the filler neck 22 the outer polygon 7 will later engage the inner polygon 27 and the bottle adapter 1 is centered in relation to the filling device 20 as a result the rods or bars 26 will then be located in the slots 9 of the outlet neck 8 and the outlet neck 8 will enter the area of the guide ring 36 due to the bottle adapter 1 being pressed the neck top side 10 of the bottle adapter is in contact with the top side 37 of the guide ring 36 and the filling valve 28 opens the adapter valve 12 is still closed if the pressure on the bottle adapter 1 is increased further the valve plate 29 is displaced against the force of the valve spring 34.