fig1 - 2 illustrate an assembly of the invention . reference numeral 1 is used to generally designate a filling device . the filling device 1 includes a filling head 2 , which can be inserted in an attachment point 4 included in an evaporator 3 . the attachment point 4 can be provided e . g . in the form of a socket , which is the case in the illustrated embodiment . the filling device 1 and the evaporator 3 are provided with conduits 5a , 5b and 6a , 6b for carrying an anesthetic from a transport container into a liquid tank included in the evaporator and for delivering a substituting gas from the liquid tank of the evaporator into the transport container . for the sake of clarity , an anesthetic transport container 15 and an evaporator liquid tank 16 are only shown in principle in fig1 . for a person skilled in the art , these features represent totally conventional technology and , thus , such features are not described in further detail in this context . the exemplary embodiment shown in the figures further comprises a clamping implement 7 for tightening the filling head against a wall of the socket serving as the attachment point 4 for the evaporator 3 . reference numerals 8 and 9 are used to generally designate valve elements , which are only adapted to open when the filling head 2 is in a position tightened against the wall of the evaporator attachment point 4 and hence to only allow a flow of anesthetic into the liquid tank of an evaporator and a flow of substituting gas into the anesthetic transport container when the filling head 2 is in a position tightened against the wall of the attachment point 4 . the assembly according to the illustrated example comprises a hydraulic container 10 , which is fitted with a first piston element 11 for the regulation of pressure existing within the hydraulic container 10 , a second piston element 12 connected to the filling - head tightening implement 7 , and a third piston element 13 connected to the valve elements 8 , 9 which control the flow of anesthetic and substituting gas . upon increasing the pressure in the hydraulic container 10 , the second piston element 12 is adapted to tighten the filling head 2 against the wall of the evaporator attachment point 4 before the third piston element 13 commences , as a result of the increase of pressure in the hydraulic container , the process of opening the valve elements 8 , 9 for allowing the flow of anesthetic and substituting gas and , respectively , upon decreasing the pressure in the hydraulic container 10 , the third piston element 13 is adapted to close the valve elements 8 , 9 before the second piston element 12 commences the process of loosening the tightening of the filling head 2 from a position compressed against the wall of the attachment point 4 . it should be noted that the third piston element can also be adapted to apply only to the liquid - conduit valve element 9 . thus , the assembly can even be fitted with a fourth piston element , which applies to the gas - conduit valve element 8 , or the gas - conduit valve element can be controlled by some other appropriate means . fig1 depicts the condition , wherein the filling head 2 is tightened against a wall of the attachment point 4 . on the other hand , fig2 depicts the condition , wherein the filling of an evaporator is completed . the second and third piston element 12 , 13 can be preferably designed as spring - loaded elements in such a manner that a spring 12a included in the second piston element 12 is adapted to develop a lesser force than a spring 13a included in the third piston element 13 . the above - described selection of springs can be used to accomplish in a preferred manner said tightening of the filling head and opening of the valve elements occurring in a proper sequence and , respectively , closing of the valve elements and release of the filling - head tightening . operation of the assembly will be described in more detail as follows . as pointed out above , the exemplary solution depicted in the figures is based on a liquid - or fluid - containing hydraulic container 10 , which is fitted with three separate hydraulic pistons , piston elements 11 , 12 , 13 . one piston 11 is linked to an actuator 11a , capable of operating the first piston element 11 and thus of regulating pressure existing in the container 10 . in the illustrated example , the second piston element 12 is connected to a spring - returnable tightener for the filling head 2 . the third piston element 13 is connected to a likewise spring - returnable filling valve 14 , which is provided with the previously mentioned valve elements 8 , 9 . the tightening - or clamping - piston spring 12a is dimensioned to be lighter than the valve - piston spring 13a . as a result of this , upon using the actuator 11a to supply more pressure into the hydraulic system , the clamping piston 12 tightens the filling head 2 against the wall of the attachment point 4 prior to opening of the filling valve , i . e . valve elements 8 , 9 . however , the clamping piston does not necessarily require a spring at all provided that the pistons have kinetic frictions which are sufficiently low for returning the clamping piston by means of hydraulic suction . the opening of the filling valve 14 , i . e . valve elements 8 , 9 , does not occur until the movement of the clamping piston stops as it comes into contact with the filling head 2 immobilized in the attachment point 4 of the evaporator . a result of the dimensioning is also an automatic closure of the filling valve 14 if the filling head 2 is disengaged while the valve elements 8 , 9 are open and the clamping piston is able to freely advance deeper into the socket serving as the attachment point 4 . thirdly , the filling valve 14 does not open at all unless the filling head 2 is in its stationary position in the evaporator attachment point 4 when supplying pressure into the hydraulic system with the assistance of the actuator 11a , the clamping piston 12 pressing unimpededly into the socket serving as the filling - device attachment point 4 . in order to achieve the above - mentioned functions , the dimensioning of pistons and the displacements thereof must be effected by taking into consideration the volume changes of the hydraulic container 10 required for each piston . the volume change created by the filling - head 2 clamping piston , i . e . the second piston element 12 , between the extreme points of a displacement is at least equal to the maximum change produced by the pressure regulation piston , i . e . the first piston element 11 . the reason for this is that , if the filling head 2 is not immobilized in its position when the pressure regulation piston 11 is operated through the action of the actuator 11a , the entire volume change must be concentrated on the clamping piston 12 for maintaining the closed condition of the filling - valve piston , i . e . the third piston element 13 , and respectively , the filling valve 14 . on the other hand , the volume change produced by the filling - valve piston 13 must be lesser than that created by the pressure regulation piston 11 , subtracted by that volume change of the clamping piston 12 , which is maximally required for tightening the filling head 2 as it is immobilized in its position . the reason for this is that the available volume change is capable of both tightening the filling head 2 and still opening the filling valve 14 . the volume change produced by the pressure regulation piston is determined from the foregoing . in the commencing condition , the filling head 2 is fitted to the attachment point 4 included in an evaporator . when using the actuator 11a and the first piston element 11 for increasing pressure in the hydraulic container 10 , the second piston element 12 begins to inch upwards in the situation shown in the figures and presses the filling head 2 against a wall of the attachment point 4 , in other words , to the position shown in fig1 . after the filling head 2 has tightened itself in the position shown in fig1 and as pressure is increased further , the third piston element 13 begins to inch to the right in the situation shown in the figures and carries at the same time the filling valve 14 to the right , whereby the valve elements 8 , 9 open and allow the flow of an anesthetic liquid and a substituting gas , as described above , from a transport container 15 into an evaporator liquid tank 16 and , respectively , from the liquid tank 16 into the transport container 15 . when disengaging the filling head 2 from the attachment point , the pressure of the hydraulic container 10 is decreased , the third piston element 13 returning first to its initial position and at the same time closing the valve elements 8 , 9 and , only thereafter , the second piston element returns to its initial position and releases the compression of the filling head 2 against a wall of the attachment point 4 . one preferred embodiment for liquid - flow and substituting - gas flow valves , i . e . the valve elements 8 , 9 , is to include the same in the elongated filling valve 14 sequentially along a common axis to extend , for example , in the direction of the filling - head attachment point 4 included in an evaporator in the immediate vicinity of flow conduits . thus , the volume from the valve closing point to the filling head 2 is as small as possible . the invention relates essentially to an arrangement associated with the above - mentioned valves . said arrangement will be described in more detail hereinbelow . in terms of the opening sequence of the valve elements , it is essential that the gas - conduit valve element 8 not open prior to the liquid - conduit valve element 9 . if this should happen , it might lead to the congestion of the gas conduit by the anesthetic liquid to preclude the filling . in case the liquid - conduit valve element 9 opens first , the liquid shall flow thereby towards the evaporator liquid tank 16 so as to induce , by means of a liquid column , an overpressure in the evaporator and an underpressure in the gas conduit . the pressure difference starts a powerful liquid flow as soon as the gas - conduit valve element 8 opens . between the gas conduits of the hydraulic fluid container 10 and the filling valve 14 are preferably fitted with both an actual piston packing 18 and also with a valve end packing 17 . the double packing is provided in order to preclude the mixing of hydraulic fluid with anesthetic liquid in case of damaged packing . a space between the packings 17 , 18 can be preferably provided with a ventilation opening wherethrough , in case of a possible packing leak fluid , the leak shall escape out and mixing is avoided . according to the basic concept of the invention , the valve elements included in gas and liquid conduits are modified relative to the prior art solutions in such a manner that , as the conduits between the transport container 15 and the evaporator liquid tank 16 are closed , i . e . as the valve elements 8 , 9 are shut off , the gas conduit 6a of a filling device closer to the transport container 15 and the corresponding liquid conduit 5a are connected to each other . in this context , the conduits 5a , 6a refer also to conduits included in the filling head 2 . in the illustrated embodiment , the conduits 5a , 6a are adapted to be connected to each other in the filling valve 14 . however , the conduits 5a , 6a can also be connected to each other not just in the filling valve , an example of this being a connection effected in the filling head in the vicinity of the valve elements 8 , 9 . in practice the connection of the conduits 5a , 6a is preferably effected as near the valve elements 8 , 9 as possible , since the evacuation shall then occur as quickly and completely as possible . fig2 depicts a situation , wherein the filling of the liquid tank 16 is completed but the filling head has not yet been released from compression . in this situation , the conduits between transport container 15 and the evaporator liquid tank 16 are closed and the gas conduit 6a and the liquid conduit 5a are in communication with each other in the filling valve 14 , as pointed out above . fig3 illustrates in an enlarged scale as to how the gas and liquid conduits are connected to each other inside the filling head in the example shown in fig1 and 2 . fig3 includes an arrow k to indicate a conduit connecting the gas and liquid conduit . fig2 includes a circle to indicate a detail depicted in fig3 . in the illustrated embodiment , as the conduits 5a , 6a between the transport container and the liquid tank are closed , i . e . as the valve elements 8 , 9 are shut off but the filling head continues to be clamped in the attachment point , a cut - off element 20 is adapted to open between the conduits for allowing the liquid to flow back into the transport container . the cut - off element 20 is in an open position in fig3 . the communication between the conduits 5a , 6a is closed whenever the cut - off element 20 squeezes against a packing 21 shown in fig3 . in an assembly of the invention , the filling valves develop no vacuum since , as the liquid flows along one conduit towards the transport container , a substituting gas is allowed to flow from the transport container towards the filling valve . fig2 includes arrows to indicate the flow of liquid and substituting gas in this situation . thus , the entire filling device drains itself quickly of the anesthetic liquid back into the transport container whereby , upon removing the filling device from the evaporator , the liquid retained between the filling device sealing and the filling valve cannot leak into the environment . however , the above - described exemplary embodiment is by no means intended to limit the invention but , instead , the invention can be modified with no restrictions within the scope of the appended claims . thus , it is obvious that an assembly of the invention or details thereof need not be exacly as depicted in the figures , but other types of solutions are conceivable as well . in the illustrated example , the invention is discussed in association with a certain type of solution . however , the invention is by no means limited to such an embodiment but , instead , the invention can be applied to any apparatus in which an evaporator is filled by connecting therewith a container carrying an anesthetic liquid .
a method and an assembly for filling an anesthetic evaporator , comprises a filling device connectable to a transport container and having a filling head which can be inserted in an attachment point included in an evaporator , the filling device and evaporator being provided with conduits for passing an anesthetic and a substituting gas between the transport container and the evaporator and the assembly comprising a clamping implement for tightening the filling head against a packing surface of the conduits arriving in the attachment point included in the evaporator and a valve element , adapted to open and thus to allow a flow of the anesthetic and the substituting gas . in view of eliminating leaks , the conduits included in the filling device and intended for the transfer of an anesthetic and the transfer of a substituting gas are adapted to be in communication with each other whenever the conduits between the filling container and the evaporator liquid tank are closed .