referring to the drawings in particular , fig1 schematically shows a longitudinal section of a connection head 1 with a valve means 2 and with an absorber 4 accommodated in a pivotable mount 3 . fig2 schematically illustrates the connection area between the connection head 1 and the absorber 4 . the connection head 1 has a housing 5 with a connection piece 6 for connection to an anesthetic breathing system , not shown more specifically in fig2 ; a guide sleeve 7 , which accommodates the valve means 2 , and an annular locking element 8 within the housing 5 with a release button 9 . the mount 3 , which receives the absorber 4 , has a barb 10 , which snaps into a wall section 11 of the locking element 8 . to connect the absorber 4 to the connection head 1 , the absorber 4 is pushed into the mount 3 and pivoted in the direction of the connection head 1 . reference is made in this connection to the disclosure of de 10 2004 020 133 b3 , which is part of this specification ( and is incorporated by reference and corresponding u . s . patent application ser . no . 11 / 058 , 624 filed feb . 15 , 2005 , is also hereby incorporated by reference . the absorber 4 has an inner gas duct 12 with an inner valve crater 13 and an outer gas duct 14 arranged concentrically thereto with an outer valve crater 15 . the gas ducts 12 , 14 describe the flow paths through the absorber 4 . the inner gas duct 12 passes within the connection head 1 through the interior space of the valve means 2 , and the outer gas duct 14 in an annular space between the valve means 2 and the guide sleeve 7 . a sealing ring 16 , which has an outer sealing lip 17 directed towards the absorber 4 , and an inner sealing lip 18 , which is in contact with an outer ring section 19 of the valve means 2 , is located on the underside of the guide sleeve 7 . the ring section 19 is located between a first cylindrical wall section 20 of the valve means 2 with the larger cross section and a second cylindrical wall section 21 with a smaller diameter , which latter wall section adjoins same . the wall sections 20 , 21 and the ring section 19 together form a valve housing 201 of the valve means 2 . the inner sealing lip 18 and the ring section 19 form a second sealing area 24 and are designed to interrupt the gas flow in the annular space as a shut - off means when the absorber 4 has been removed from the connection head 1 . the second wall section 21 is provided with an elastomer ring 22 at its free end , which extends in the direction of the absorber 4 . when the absorber 4 is pivoted in the direction of the connection head 1 , the outer sealing lip 17 lies on the outer valve crater ( seat ) 15 and forms a first sealing area 23 . the elastomer ring 22 is located on the inner valve crater 13 in this position of the absorber 4 . a flow valve 31 with a valve body 25 , which is in contact with a sealing lip 26 , is located on the top side of the first wall section 20 of the valve means 2 . the valve body 25 is pressed by a compression spring 27 against the sealing lip 26 . the valve body 25 is in contact with a projection 29 of the housing 5 via spacers 28 . due to the fixation by means of the spacers 28 , the valve body 25 always has a fixed position in relation to the housing 5 . the flow valve 31 opens when the valve housing 201 is displaced in the direction of the spacers 28 . in the position of the absorber 4 shown in fig2 , the path of gas 30 extends via the inner gas duct 12 through the free spaces between the spaces 28 to the outer gas duct 14 . fig3 shows the connection head 1 with the connected absorber 4 . fig4 shows the connection area between the connection head 1 and the absorber 4 corresponding to fig3 in a longitudinal section . identical components are designated by the same reference numbers as in fig1 and 2 . the barb 10 has snapped into the wall section 11 of the spring element 8 in the coupled state . the outer valve crater 15 is in contact with the outer sealing lip 17 . the inner valve crater 13 is located at the elastomer ring 22 and presses the valve housing 201 of the valve means 2 upward against the force of the compression spring 27 . since the valve body 25 is supported at the projection 29 via the spacers 28 and thus remains in its original position , the sealing lip 26 lifts off from the valve body 25 and the flow valve 31 is opened . at the same time , the ring section 19 separates from the inner sealing lip 18 and the second sealing area 24 is opened . the path of gas 30 from the anesthetic breathing system now leads via the opened flow valve 31 in the inner gas duct 12 and to the absorber 4 . the backflow takes place via the outer gas duct 14 , the opened second sealing area 24 and the annular gap between the valve means 2 and the guide sleeve 7 back to the anesthetic breathing system . the outer sealing lip 17 is designed in this embodiment as a lip seal with a large deformation area in order to reduce the sealing forces that must be overcome when the mount 3 is coupled with the connection head 1 and to compensate differences in height in the form of manufacturing tolerances . with the absorbed 4 uncoupled , the sealing ring 16 is pulled off from the guide sleeve 7 downward for cleaning purposes and the valve means 2 can be removed and taken apart for cleaning purposes . no tool is necessary for disassembly . the components of the connection head 1 may be manufactured from plastic according to the injection molding process and can be manufactured at a very low cost as a result . fig5 shows a bottom view of the connection head 1 with the valve means 2 removed and with the bracket 3 removed in view “ a ” according to fig2 . the mount 3 is fastened pivotably in the bushes 32 of the housing 5 . the locking element 8 has spacing elements 33 , which are in contact with a leaf spring 36 , the leaf spring 36 being supported at projections 34 of the housing 5 . fig6 shows the locking element 8 in a perspective view . the locking element 8 comprises a rigid frame 35 , to which the likewise rigid spacing elements 33 are fastened . when pressure is applied to the release button 9 , the frame 35 deforms and the wall section 11 is displaced in the direction of arrow 37 against the spring force of the leaf spring 36 , fig5 . the stroke of the locking element 8 is limited by a contact surface 38 , which is in contact with the housing 5 , fig5 , at maximum deflection . when pressure is applied to the release button 9 , the barb 10 , fig2 , is released . fig7 illustrates the absorber 4 in a perspective view . a guide plate 40 is fastened to the top side of an absorber housing 39 , and guide grooves 41 , 42 arranged opposite each other are provided between the guide plate 40 and the absorber housing 30 . the guide plate 40 has upper positioning grooves 43 , 44 arranged opposite each other in the area of the guide grooves 41 , 42 and lower positioning grooves 45 , 46 extending flush with the upper positioning grooves 43 , 44 . fig8 shows the absorber 4 in the area of the guide plate 40 in a perspective view . identical components are designated by the same reference numbers as in fig7 . fig9 shows the absorber 4 before insertion into the mount 3 of the connection head 1 . the connection head 1 has centering pins 47 , 48 , which are arranged opposite each other and of which only the front centering pin 47 is shown in fig9 . the centering pins 47 , 48 are designed as pins tapering in a wedge - shaped manner towards the free end . to connect the absorber 4 to the mount 3 , the absorber is pushed into the underside 50 of the mount 3 along arrow 49 . the underside 50 is beveled for this inwardly , so that the guide plate 40 is held by the underside 50 . the guide grooves 41 , 42 extend in the area of the centering pins 47 , 48 . fig1 shows the mount 3 with the absorber 4 pushed in . fig1 shows the mount 3 with the absorber 4 inserted , the mount being cut open along the section lines 51 , 52 . the centering pin 47 is located in the area of the upper positioning groove 44 of the guide plate 40 . identical components are designated by the same reference numbers as in fig8 and 9 . the mount 3 is fastened such that it can be pivoted about a pin joint 53 fastened to the connection head 1 . fig1 shows the mount 3 connected to the connection head 1 . the front centering pin 47 is located completely within the upper positioning groove 44 and lies with its tip within the lower positioning groove 46 . the rear centering pin 48 , not shown in fig1 , is located within the rear upper positioning groove 43 and lies with its tip within the lower positioning groove 45 . the free ends of the centering pins 47 , 48 taper in a wedge - shaped manner , and the inner walls of the upper positioning grooves 43 , 44 and of the lower positioning grooves 45 , 46 are designed corresponding thereto , so that the absorber 4 has only a very small clearance in relation to the connection head 1 . while a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention , it will be understood that the invention may be embodied otherwise without departing from such principles .
a carbon dioxide absorber for a rebreathing system can be connected to a connection head of the rebreathing system in a simple manner . a centering device , provided in the area of a guide plate of the absorber , can be caused to mesh with centering pins pointing in the direction of the absorber from the connection head .