Patent Publication Number: US-2020284465-A1

Title: Exhaust pipe system

Description:
The invention relates to an exhaust pipe system for conducting exhaust gas from a combustion device to an exhaust system, having an exhaust pipe with an inlet end and an outlet end, which is formed to be connectable to the exhaust system, wherein within the first exhaust pipe a locking member which is movable between a closed position which closes a passage from the inlet end to the outlet end and an open position which opens the passage is arranged. 
     The starting point for the invention are known exhaust pipe systems in apartment buildings. These known exhaust pipe systems connect a combustion device existing in an apartment of an apartment building with an exhaust system which leads to a chimney and to which all combustion devices of the individual apartments are connected. For such an installation situation it has to be considered that it can happen that the flats are ready for occupancy at different times, so that a combustion device of one flat is already in operation and the exhaust gas is led to the chimney via the common exhaust system, while in another flat an exhaust pipe is connected to the exhaust system, but the combustion device is not yet installed. In such case it is known that a cover cap closes an inlet end of the already installed exhaust pipe connected to the exhaust system so that no exhaust gas which is conveyed from another flat to the exhaust system from a combustion device in operation there reaches the flat where no combustion device is yet connected to the exhaust pipe. Such cover caps will also be used when maintenance work is carried out on a combustion device which requires the exhaust pipe between the exhaust system and the combustion device to be disassembled. Such cover cap is not attached particularly securely to the exhaust pipe leading to the exhaust system, so that there is a risk that the cover cap could come loose and exhaust gas could enter the flat. 
     The invention is, therefore, based on the object of providing an exhaust pipe system of the above-mentioned type which does not have the mentioned risk and which provides a locking member which automatically closes an exhaust pipe if necessary. 
     This object is achieved, according to the invention, by an exhaust pipe system for conducting exhaust gas from a combustion device to an exhaust system. The exhaust pipe system according to the invention comprises a first exhaust pipe with an inlet end and an outlet end, which is formed to be connectable to the exhaust system, and a second exhaust pipe with a first line end and a second line end, which is designed to be connectable to the combustion device. The inlet end of the first exhaust pipe is connectable to the first line end of the second exhaust pipe via a detachable coupling connection, wherein within the first exhaust pipe a locking member is arranged which is movable between a closed position closing a passage from inlet end to outlet end and an open position opening the passage. When the coupling connection is canceled, the locking member is automatically arranged in the closed position. According to the invention, the second exhaust pipe has an actuating member which, when the coupling connection has been established, urges the locking member in the open position. 
     Advantageous and suitable designs and further developments of the invention will emerge from the subclaims. 
     The invention provides an exhaust pipe system which is characterized by a simple and functional construction to avoid the above-mentioned risk. The exhaust pipe system according to the invention consists of a first exhaust pipe and a second exhaust pipe, wherein the locking member arranged within the first exhaust pipe can only be moved from its closed position into its open position if the second exhaust pipe is connected to the first exhaust pipe via the coupling connection. Because only in this case the actuating member of the second exhaust pipe is able to act on the locking member and move the locking member into the open position. Therefore, the exhaust pipe system according to the invention consists of two exhaust pipes matched to each other, wherein the locking member can only be moved into the open position with the aid of the second exhaust pipe with the actuating member, which is not possible with any other conventional exhaust pipe. The invention is, therefore, a set of exhaust pipes, wherein the locking member is arranged in the exhaust pipe, which is already installed in a wall of a building, wherein only the second exhaust pipe matching this exhaust pipe is capable of moving the locking member into the open position when a coupling connection is established and thereby opening the passage to the exhaust system. As long as the coupling connection is established, the locking member is in the open position. The locking member is only arranged in the closed position if the second exhaust pipe is not connected to the first exhaust pipe. 
     The invention is designed in such a way that the locking member is formed as a rotatably mounted and axially displaceable butterfly valve. The design of the butterfly valve has the advantage of a low flow resistance compared to other shut-off means. 
     It is particularly advantageous if the actuating member moves the butterfly valve in the direction of the outlet end when it moves into the open position. The edge of the butterfly valve rests on a sealing seat in the closed position, wherein the edge is provided with a sealing lip. The movement from the closed position to the open position is a rotary movement of the butterfly valve, whereby the sealing lip would be heavily loaded if it only rotated and there would be a risk that the sealing lip would fold over and that a movement back to the closed position would not produce a sufficient sealing effect. The fact that the butterfly valve, according to the invention, is also moved axially in the direction of the outlet end during its movement into the open position and axially in the direction of the inlet end on the sealing seat during its movement into the closed position means that this risk no longer exists. 
     In order to realize the axial movement and rotary movement of the butterfly valve, according to an embodiment the invention provides for two bearing pins arranged on opposite sides to be formed on the butterfly valve, each of which is guided by a guide track formed on the inside of the first exhaust pipe. 
     Constructively advantageous and for a compact structural shape, the design of the invention provides that the bearing pins extend in the direction of the outlet end and radially from the butterfly valve with respect to the closed position of the butterfly valve. 
     According to a first embodiment, the invention provides that a partial line within the first exhaust pipe is movably mounted in the direction of the outlet end and protrudes in portions from the inlet end. The partial line serves to move the butterfly valve, which is why the partial line is arranged movably within the first exhaust pipe. 
     It is particularly advantageous if, in another embodiment, two opposing movement recesses extending in the axial direction are formed in the partial line, in each of which a guide projection formed on the inside of the first exhaust pipe and between the butterfly valve and the inlet end is arranged. 
     The partial line is arranged in the closed position of the butterfly valve in a rear position with respect to the outlet end and is moved in the direction of the outlet end when the butterfly valve moves. The invention provides for the partial line to be mounted movably against the force of a mechanical resetting member along the respective guide projection in the direction of the outlet end. 
     With regard to the movement of the butterfly valve, the invention in another embodiment provides that two guide tracks are formed on the butterfly valve which, with respect to the closed position, are formed on the side of the butterfly valve facing the inlet end, wherein two pivot pins are formed on the end of the movement recesses on the partial line, which engage in the guide tracks of the butterfly valve, wherein when the butterfly valve moves from the closed position into the open position, the pivot pins are designed to move from one end of the assigned guide tracks to the other end of the assigned guide tracks and to move the butterfly valve first axially in the direction of the outlet end and then to be pivotable around the bearing pins. 
     A constructively favorable option for realising the movement of the partial line is provided in another embodiment in that a radially outwardly extending actuating collar is formed at the end of the partial line projecting from the inlet end, wherein the actuating member is formed as a radial web which, when a coupling connection is established, displaces the partial line in the direction of the outlet end and urges the locking member in the open position. 
     According to another embodiment, the invention provides that the butterfly valve is coupled to an actuating arm, located within the first exhaust pipe, wherein the actuating arm is located between the butterfly valve and the inlet end, and wherein the actuating arm is located in the closed position in a retracted holding position toward the inlet end and is moved toward the outlet end when the coupling connection is established, and is arranged to hold the butterfly valve in the open position. This embodiment is, therefore, more compact and does not require the partial line to move the butterfly valve. 
     In another design of the further embodiment, the invention provides for the actuating arm to be mounted axially movably in a guide rail formed on the first exhaust pipe. Consequently, there is no complex pivot movement but only an axial movement is provided for the actuating arm. 
     For the movement coupling with the butterfly valve, it is of structural advantage if the actuating arm has a pivot recess at the end into which a pivot pin is arranged to be movable and guided, wherein the pivot pin is formed with respect to the closed position on the side of the butterfly valve facing the inlet end. 
     Furthermore, it is provided in the design of another embodiment that the actuating member is in the form of a tappet or pusher which is formed on the inside of the second exhaust pipe and which arranges the actuating arm so as to move in the direction of the outlet end against the force of a mechanical resetting member. 
     For both embodiments, it is provided in the design of the invention that the detachable coupling connection is in the form of a threaded connection, a bayonet connection, a latching connection or a force-fitting and/or form-fitting clamping connection. These possibilities of formation ensure a safe and stable connection. 
     The invention may be supplemented such that according to a design, the first exhaust pipe is surrounded by a first combustion air line, wherein the second exhaust pipe is surrounded by a second combustion air line, wherein the first combustion air line and the second combustion air line are formed to be connectable with each other, and wherein a circumferential gap is formed between the first and second combustion air lines and the first and second exhaust pipes for guiding combustion air in the direction of the second line end. Thus, for example, a concentric line assembly can be realized if the individual lines are tubular and circular in cross-section, wherein the exhaust pipes then represent a kind of inner pipe which is concentrically surrounded by an outer pipe formed by the combustion air lines, wherein the combustion air required for combustion is then conveyed to the combustion device through the annular gap. 
     For establishing and removal of the coupling connection, which can no longer be handled by a user from the outside in a concentric pipe assembly, the invention in an embodiment provides that an external thread is formed at the first line end of the second exhaust pipe, wherein the second combustion air line is connected to a connecting member at the end to be connected to the first combustion air line via a latching connection, which is arranged within the second combustion air line and has an internal thread, and wherein the internal thread of the connecting member can be brought into engagement with the external thread of the second exhaust pipe in such a way that the coupling connection can be produced or removed by actuation of the second combustion air line. 
     It is particularly advantageous if the latching connection is formed by latching hooks which alternately engage behind a first circumferential edge and a second circumferential edge of the connecting member. This makes it possible to move the second exhaust pipe in both axial directions. 
     Finally, it is provided in an embodiment of the invention that at least one connecting recess is formed on the connecting member, and wherein one of the latching hooks is arranged horizontally in the connecting recess in such a way that the connecting member and the second combustion air line are form-fittingly connected to one another. The form-fitting connection ensures that when the second combustion air line is rotated, the connecting member is also rotated to rotate the second exhaust pipe, which ultimately establishes or removes the coupling connection between the first exhaust pipe and the second exhaust pipe. 
     It should be understood that the features mentioned above and those still to be explained below can be used not only in the combination indicated but also in other combinations or in a unique position, without leaving the scope of the present invention. The scope of the invention is defined only by the claims. 
    
    
     
       Further details, features, and advantages of the subject-matter of the invention result from the following description in connection with the drawing, in which exemplary and preferred exemplary embodiments of the invention are presented. 
       In the drawing: 
         FIG. 1  shows a schematic side view of an apartment building, 
         FIG. 2  shows a perspective view of an exhaust pipe system according to the invention, according to a first embodiment, 
         FIG. 3  shows another perspective view of the exhaust pipe system shown in  FIG. 2 , in which a coupling connection between a first exhaust pipe and a second exhaust pipe is removed, 
         FIG. 4  shows a perspective sectional view of the second exhaust pipe, 
         FIG. 5  shows a sectional side view of the first exhaust pipe, with a locking member arranged inside and a partial line movably mounted on the first exhaust pipe, 
         FIG. 6  shows another sectional side view of the first exhaust pipe, 
         FIG. 7  shows a perspective sectional view of the partial line, 
         FIG. 8  shows a perspective representation of the partial line, 
         FIG. 9  shows a perspective view of the first exhaust pipe, 
         FIG. 10  shows a side representation of the partial line movably coupled with the locking member, 
         FIG. 11  shows a sectional side view of the first exhaust pipe with the locking member arranged in a closed position, 
         FIG. 12  shows a sectional side view of the first exhaust pipe which is connected to the second exhaust pipe via the coupling connection, wherein the locking member is arranged in an open position, 
         FIG. 13  shows a perspective view of an exhaust pipe system according to the invention, according to a second embodiment, 
         FIG. 14  shows another perspective view of the exhaust pipe system shown in  FIG. 13 , in which the coupling connection between the first exhaust pipe and the second exhaust pipe is removed, 
         FIG. 15  shows a perspective sectional view of the second exhaust pipe for the second embodiment, 
         FIG. 16  shows a sectional side view of the first exhaust pipe for the second embodiment, 
         FIG. 17  shows a perspective sectional representation of the first exhaust pipe for the second embodiment, 
         FIG. 18  shows a perspective view of the locking member and an actuating arm movably coupled with it according to the second embodiment, 
         FIG. 19  shows a sectional side view of the first exhaust pipe according to the second embodiment, wherein the locking member is arranged in the closed position, 
         FIG. 20  shows a sectional side view of the first exhaust pipe according to the second embodiment which is connected to the second exhaust pipe via the coupling connection, wherein the locking member is arranged in the open position, 
         FIG. 21  shows a concentric embodiment of the exhaust pipe system with a first combustion air line and a second combustion air line according to the invention, 
         FIG. 22  shows a sectional side view of the concentric embodiment of the exhaust pipe system according to the invention, 
         FIG. 23  shows a perspective representation of a connecting member of the concentric embodiment of the exhaust pipe system according to the invention, 
         FIG. 24  shows a perspective view of the second combustion air line, 
         FIG. 25  shows a perspective sectional view of the connecting member and the second combustion air line, and 
         FIG. 26  shows a rear view of the connecting member and the second combustion air line. 
     
    
    
       FIG. 1  schematically shows a side view of an apartment building  1  with three housing units  2 ,  3  and  4 . A combustion device  5  is installed in each of the individual housing units  2 ,  3  and  4 , wherein the respective combustion devices  5  of the lower and upper housing units  2  and  4  are connected to a central exhaust system  7  leading to a chimney  6 . The connection between the combustion device  5  and the exhaust system  7  is realized by means of an exhaust pipe system  8  according to the invention. The exhaust pipe system  8  thereby serves to conduct exhaust gas from the combustion device  5  to the exhaust system  7  and comprises a first exhaust pipe  9  and a second exhaust pipe  10 , wherein a locking member  11  not shown in  FIG. 1  is arranged inside the first exhaust pipe  9  and the first exhaust pipe  9  is permanently installed in the wall. For the housing units  2  and  4 , the respective locking member  11  is in an open position so that exhaust gas from the combustion device  5  can reach the exhaust system  7 . As can be seen from  FIG. 1 , for housing unit  3  the combustion device  5  is separated from the exhaust system  7  by dismantling the second exhaust pipe  10 . When the second exhaust pipe  10  is dismounted, the locking member  11  within the first exhaust pipe  9  automatically assumes a closed position so that no exhaust gas can escape from the exhaust system  7  into the housing unit  3 . The locking member  11  is formed as a rotatable and axially displaceable butterfly valve  23 , which will be discussed below. 
       FIGS. 2 to 12  show a first embodiment of the exhaust pipe system  8  according to the invention,  FIGS. 13 to 20  show a second embodiment of the exhaust pipe system  8  according to the invention and  FIGS. 21 to 26  show a concentric embodiment of the exhaust pipe system  8  according to the invention. In order to avoid repetitions, the commonalities for all embodiments are addressed below. The first exhaust pipe  9  and the second exhaust pipe  10  are tubular and circular formed in a cross-section, wherein other forms, such as an angular or an oval cross-section, are also conceivable. The first exhaust pipe  9  has an inlet end  12  and an outlet end  14  (see, for example,  FIGS. 3 and 14 ), wherein the outlet end  14  is designed to be connectable to the exhaust system  7 . The second exhaust pipe  10  has a first line end  15  and a second line end  16  (see, for example,  FIGS. 3 and 14 ), wherein the second line end  16  is formed to be connectable to the combustion device  5 . 
     With reference to  FIGS. 2 to 12  and thereby to the first embodiment, the inlet end  12  of the first exhaust pipe  9  is detachably connected to the first line end  15  of the second exhaust pipe  10  via a threaded connection  17 . In general, the threaded connection  17  represents a detachable coupling connection  18 , which is formed in the first embodiment by pins  19  on the outside and arranged opposite of each other, which are integrally formed on the first exhaust pipe  9 , and from the inside and arcuately extending recesses  20 , which are formed on the second exhaust pipe  10 . One of the two pins  19  is shown in  FIG. 3 , whereas one of the two recesses  20  is shown in  FIG. 4 . In  FIG. 2 , the coupling connection  18  between the first exhaust pipe  9  and the second exhaust pipe  10  is established, wherein with the established coupling connection  18  the locking member  11  is arranged compressed in the open position. The  FIG. 5  shows a sectional side view of the first exhaust pipe  9  with the locking member  11  arranged therein, which is arranged in a closed position closing a passage  21  of the first exhaust pipe  9  due to the removed coupling connection  18 , wherein  FIG. 5  also shows a partial line  22  movably mounted on the first exhaust pipe  9 . Two bearing pins  24 ,  25  arranged opposite of each other are formed on the locking member  11  or on the butterfly valve  23  (see, for example,  FIG. 10 ), via which the locking member  11  is movably mounted on the first exhaust pipe  9 . The two bearing pins  24 ,  25  extend with reference to the closed position of the locking member  11  or the butterfly valve  23  in the direction of the outlet end  14  and radially, i.e. laterally, from the butterfly valve  23 . The bearing pins  24 ,  25  of the butterfly valve  23  are each arranged in a guide track  26 . In the first embodiment, the guide track  26  runs in an axial direction and extends in the direction of the outlet end  14 . In  FIGS. 5, 6, 11 and 12  only one guide track  26  is shown, wherein the other guide track  26  is arranged opposite the shown guide track  26  and is formed on the inside of the first exhaust pipe  9 . The butterfly valve  23  is thereby mounted both rotatably and axially via its bearing pins  24 ,  25  in the guide tracks  26 . As it can be seen in particular from  FIGS. 6 and 27 , the guide track  26  is formed with a wider area in the direction of the outlet end  14 , wherein the bearing pins  24 ,  25  have a specific bearing contour. Due to this bearing contour, only axial movement is possible for the bearing pins  24 ,  25  at the respective end of the guide tracks  26  facing away from the outlet end  14 . If the respective bearing contour then reaches the extended area formed at the end of the guide track  26  facing the outlet end  14 , a rotary movement of the bearing pins  24 ,  25  is possible, but no other axial movement. 
     As shown in  FIG. 10 , the locking member  11  or the butterfly valve  23  is movably coupled with the partial line  22 , wherein the partial line  22  protrudes in portions from the inlet end  12  (see  FIG. 5 ). On the butterfly valve  23 , at the edge of the butterfly valve  23 , two opposite guide tracks or slotted guides  27  are formed, wherein in  FIG. 10  only the front guide track or slotted guides  27  can be seen. The guide tracks or slotted guides  27  are formed with reference to the closed position on the side of the butterfly valve  23  facing the inlet end  12 . Furthermore, two pivot pins  28  (see  FIGS. 8 and 10 ) are formed on the partial line  22 , which are formed on the ends of the coupling projections  29 , which are formed opposite of each other on the partial line  22  and which extend axially. A respective pivot pins  28  of the partial line  22  engages in the assigned guide track or slotted guides  27  of the butterfly valve  23 . 
     The partial line  22  is movably mounted within the first exhaust pipe  9  in the direction of the outlet end  14 . For this purpose, opposite movement recesses  30  are formed in the partial line  22  (see, for example,  FIGS. 8 and 9 ), which each extend in axial direction  31  to each coupling projection  29 . On the inside of the first exhaust pipe  9 , guide projections  32  (see, for example,  FIG. 6 ) are also formed, which are on opposite sides to each other and are formed between the butterfly valve  23  and the inlet end  12 . A respective guide projection  32  has a pin-shaped receptacle  33  for a compression spring which is fitted onto the pin-shaped receptacle  33  and which extends as far as a pin-shaped stopper which is formed in the movement recess  30  of the partial line  22 . The compression spring represents a mechanical resetting member, against whose force the partial line  22  is mounted on the first exhaust pipe  9  so that it can move along the respective guide projection  32  in the direction of the outlet end  14 . In addition, the movement of the partial line  22  is guided by two guide webs  34  (see, for example,  FIG. 9 ) which are formed inside the first exhaust pipe  9  and extend in the axial direction  31 , wherein the guide webs  34  are arranged horizontally in recesses  35  (see, for example,  FIG. 8 ) which are formed on the partial line  22 . The coupling projections  29 , which are coupled to the butterfly valve  23 , are guided in the manner of a carriage and can be moved against the force of the mechanical resetting member in the direction of the guide projections  32 , so that the partial line is guided in the direction of the outlet end  14  within the first exhaust pipe  9 . 
     If the partial line  22  moves within the first exhaust pipe  9  in the direction of the outlet end  14 , this leads to a movement of the butterfly valve  23  due to the coupling with the butterfly valve  23 , whereupon the following is discussed with reference to  FIGS. 11 and 12 . 
       FIG. 11  shows the first exhaust pipe  9  with the locking member  11  arranged in the closed position, which is the butterfly valve  23 . In the assembly shown in  FIG. 11 , the mechanical resetting member pushes the partial line  22  into a position in which the partial line  22  protrudes from the first exhaust pipe  9 . An edge  36  of the partial line  22  within the first exhaust pipe  9  is horizontally arranged between a sealing seat  37 , which is formed on the inside of the first exhaust pipe  9  and on which the butterfly valve  23  rests in its closed position, and the inlet end  12 . The bearing pins  24 ,  25  of the butterfly valve  23  are arranged within the guide track  26  and at one end of the guide track  26  which points away from the outlet end  14 . In  FIG. 11 , the coupling connection  18  is removed because the second exhaust pipe  10  is dismantled from the first exhaust pipe  9 . As a result, the mechanical resetting member pushes the partial line  22  in portions out of the inlet end  12 , wherein the butterfly valve  23  is automatically arranged in the closed position due to the movement coupling of partial line  22  and butterfly valve  23 . The pivot pins  28  of the coupling projections  29  are located at the respective ends of the guide recesses or slotted guides  27  of the butterfly valve  23 . 
     In  FIG. 12 , the second exhaust pipe  9  is connected to the first exhaust pipe  10  via the coupling connection  18 , wherein the locking member  11  and the butterfly valve  23 , respectively, are arranged in the open position. A radially outwardly extending actuating collar  38  is formed at the end of the partial line  22  that protrudes from the inlet end  12  (see  FIGS. 7 and 10 , for example). A radial and step-shaped web  39 , which represents an actuating member  40 , is formed on the second exhaust pipe  10  (see  FIG. 4 ). To establish the coupling connection  18 , the second exhaust pipe  10  is screwed onto the first exhaust pipe  9  via the threaded connection  17 . The actuating member  40  formed on the second exhaust pipe  10  presses against the actuating collar  38  formed on the partial line  22  and pushes the partial line  22  in the direction of the outlet end  14 . Consequently, when the coupling connection  18  is established, the actuating member  40  arranges the partial line  22  displaced in the direction of the outlet end  14 , wherein the partial line  22  thereby urges the locking member  11  in the compressed open position. As can be seen in  FIG. 12 , in the open position of the butterfly valve  23  the edge  36  of the partial line  22  is now arranged displaced in the direction of the outlet end  14  of the first exhaust pipe  9 , wherein in the open position of the butterfly valve  23  the edge  36  is arranged horizontally between the outlet end  14  and the sealing seat  37 . Due to the movement coupling of the partial line  22  with the butterfly valve  23  in the open position of the butterfly valve  23 , after the butterfly valve  23  has been moved out of the closed position and the partial line  22  has been moved against the force of the mechanical resetting member, the pivot pins  28  are arranged so as to move from one end of the assigned guide tracks or slotted guides  27  to the other end of the assigned guide track or slotted guide  27 . When the butterfly valve  23  moves out of the closed position in the direction of the open position, the actuating member  40  first moves the butterfly valve  23  axially in the direction of the outlet end  14  via the partial line  22 , wherein the bearing pins  24 ,  25  of the butterfly valve  23  are displaced in the direction of the outlet end  14 . The partial line  22  first moves the butterfly valve  23  away from the sealing seat  37  and translatorically in the direction of the outlet end  14 . This axial and purely translational movement is then followed by the rotary movement of the butterfly valve  23  or the bearing pins  24 ,  25 , whereby the butterfly valve  23  opens the passage  21 . The butterfly valve  23  is, therefore, firstly axially movable in the direction of the outlet end  14  and then pivotable formed around the bearing pins  24 ,  25 . In the open position, the bearing pins  24 ,  25  are arranged at one end of the respective guide track or slotted guide  27  facing the outlet end  14 . 
     With reference to  FIGS. 13 to 20 , in the second embodiment the inlet end  12  of the first exhaust pipe  9  is detachably connected to the first line end  15  of the second exhaust pipe  10  via a bayonet connection  41 . The bayonet connection  41  represents the detachable coupling connection  18  which, in the second embodiment, is formed by pins  42  on the outside and opposite to each other which are formed on the first exhaust pipe  9 , and by interlocking recesses  43  which are formed on the first line end  15  of the second exhaust pipe  10  (see for example  FIG. 14 ). In  FIG. 13 , the coupling connection  18  between the first exhaust pipe  9  and the second exhaust pipe  10  is established, wherein the locking member  11  is urged in the forced open position when the coupling connection  18  is established.  FIG. 16  shows a sectioned perspective view of the first exhaust pipe  9  with the locking member  11  arranged in it, which is arranged in a closed position closing the passage  21  of the first exhaust pipe  9  due to the removed coupling connection  18 . Also in the second embodiment, two opposite bearing pins  24 ,  25  are formed on the locking member  11  or on the butterfly valve  23  (see, for example,  FIG. 18 ), via which the locking member  11  is movably mounted on the first exhaust pipe  9 . The two bearing pins  24 ,  25  extend with reference to the closed position of the locking member  11  or the butterfly valve  23  in the direction of the outlet end  14  and radially, i.e. laterally, from the butterfly valve  23 . In this embodiment too, the bearing pins  24 ,  25  of the butterfly valve  23  are each arranged in a guide track  26 . However, in the second embodiment, the guide track  26  is essentially L-shaped formed, as it can be seen, for example, from  FIG. 17 . The guide track  26  is divided into an axial portion formed at the end of the guide track  26  facing away from the outlet end  14  and a vertical portion adjacent to the axial portion. In  FIGS. 17, 19 and 20  only one guide track  26  is shown, wherein the other guide track  26  is arranged on the opposite side of the shown guide track  26  and is formed on the inside of the first exhaust pipe  9 . The bearing pins  24 ,  25  are thereby mounted both rotatably and axially and vertically displaceably in the guide tracks  26 . 
     As shown in  FIG. 16 , the locking member  11  or the butterfly valve  23  is coupled to an actuating arm  44  arranged within the first exhaust pipe  9 . The actuating arm  44  is located between the butterfly valve  23  and the inlet end  12 . Furthermore, the actuating arm  44 , which is angular or L-shaped formed, is mounted axially movably in a guide rail  45  fastened to the first exhaust pipe  9  (see, for example,  FIGS. 16 and 18 ). Thus the butterfly valve  23 , the actuating arm  44  and the guide rail  45  can be mounted together as one unit on the first exhaust pipe  9 , wherein the mounting takes place via a latching connection which comprises a latching hook  46  formed on the guide rail  45  and a latching tab  47  formed on the first exhaust pipe  9  (see  FIGS. 16, 17 and 18 ). The end of the actuating arm  44  arranged horizontally in the guide rail  45  can be moved against the force of a mechanical resetting member, which can also be a compression spring in this embodiment, in the direction of the outlet end  14  in the guide rail  45 . A pivot pin  48  (see  FIG. 16 ) is formed in the middle of the butterfly valve  23 . The pivot pin  48  is formed with reference to the closed position of the butterfly valve  23  on the side of the butterfly valve  23  facing the inlet end  12 . Furthermore, the angular actuating arm  44  has a pivot recess  49  at its end and at its end facing away from the guide rail  45 , into which the pivot pin  48  of the butterfly valve  23  is arranged so as to be movable and guided. The butterfly valve  23  and the actuating arm  44  are movement coupled to each other by the pivot pin  48  and the pivot recess  49 . Furthermore, in the second embodiment, the actuating member  40  is formed as a formed tappet or pusher  50  on the inside of the second exhaust pipe  10  (see, for example,  FIG. 15 ). 
     When the actuating arm  44  moves within the first exhaust pipe  9  in the direction of the outlet end  14 , the coupling with the butterfly valve  23  results in a movement of the butterfly valve  23 , which is described below with reference to  FIGS. 19 and 20 . 
       FIG. 19  shows the first exhaust pipe  9  with the locking member  11  arranged in the closed position, which is the butterfly valve  23 . In the assembly shown in  FIG. 19 , the mechanical resetting member urges the actuating arm  44  into a holding position retracted towards the inlet end  12  so that in the closed position of the butterfly valve  23  the actuating arm  44  is in the holding position. As can be seen from  FIG. 20 , the actuating arm  44  is moved in the direction of the outlet end  14  when the coupling connection  18  is established and the butterfly valve  23  is arranged so as to hold it in the open position. When the coupling connection  18  is established, the actuating member  40  formed as a tappet or pusher  50  presses against an actuating end  51  of the actuating arm  44 . The actuating end  51  protrudes from the guide rail  45  and the inlet end  12  of the first exhaust pipe  9  when the coupling connection  18  is removed, as shown in  FIG. 19 . Upon coupling connection  18  being established, the tappet or pusher  50  or the actuating member  40  then urges the actuating arm  44  against the force of a mechanical resetting member in the direction of the outlet end  14  until the actuating end  51  is located within the guide rail  45  and the tappet or pusher  50  or the actuating member  40  itself rests against the guide rail  45 , wherein the guide rail  45  represents a movement limitation for the actuating member  40 . Upon axial movement of the actuating arm  44  by means of the actuating member  40 , the actuating arm  44  moves in the direction of the outlet end  14 . Due to the movement coupling of the actuating arm  44  with the butterfly valve  23 , in the open position of the butterfly valve  23 , after the butterfly valve  23  has been moved out of the closed position and the actuating arm  44  has been moved against the force of the mechanical resetting member, the pivot pin  48  is arranged to move from one end of the pivot recess  49  to the other end of the pivot recess  49 . Upon movement of the butterfly valve  23  from the closed position to the open position, the actuating member  40  first moves the butterfly valve  23  axially in the direction of the outlet end  14  via the actuating arm  44  and then vertically, wherein the bearing pins  24 ,  25  of the butterfly valve  23  are displaced in the direction of the outlet end  14  and then vertically. The actuating arm  44  first moves the butterfly valve  23  away from the sealing seat  37  and axially or translatorily in the direction of the outlet end  14 . This axial or translational movement is then followed by the vertical movement and the rotary movement of the butterfly valve  23 , whereby the butterfly valve  23  opens the passage  21 . The butterfly valve  23  can therefore first be moved axially in the direction of the outlet end  14  and can then be pivotable formed around the bearing pins  24 ,  25 . 
     In  FIGS. 21 to 26 , another embodiment for a concentric design is shown. At this concentric design, the first exhaust pipe  9  is surrounded by a first combustion air line  52 . Furthermore, the second exhaust pipe  10  is surrounded by a second combustion air line  53 . The first combustion air line  52  and the second combustion air line  53  are formed to be connectable with each other, wherein the connection can be realized by a threaded connection, bayonet connection, latching connection, or a force-fitting and/or form-fitting clamping connection or another type of connection. The first combustion air line  52  together with the second combustion air line  53  forms a passage, wherein a circumferential gap  54  is formed between this passage and the first and second exhaust pipes  9 ,  10 , which serves to guide the combustion air in the direction of the second line end  16  (see for example  FIG. 22 ). The first combustion air line  52  is, like the first exhaust pipe  9 , permanently installed in a wall of a house, for example an apartment building  1 . In order to facilitate the mounting of this concentric assembly, an external thread is formed at the first line end  15  of the second exhaust pipe  10 . Furthermore, a connecting member  55  is provided, which has an internal thread. The internal thread of the connecting member  55  can be brought into engagement with the external thread of the second exhaust pipe  10 . Furthermore, the second combustion air line  53  is connected to the connecting member  55  at the end to be connected to the first combustion air line  52  via a latching connection  56 . The connecting member  55  is located inside the second combustion air line  53 . The connecting member  55  is shown in  FIG. 23  and has a first circumferential edge  57  and a second circumferential edge  58 . Furthermore, latching hooks  59 ,  60  are formed on the second combustion air line  53 , which extend radially inwards. The latching hooks  59 ,  60  alternately engage behind the first circumferential edge  57  and the second circumferential edge  58  of the connecting member  55  and are uniformly circumferentially spaced. The latching connection  56  is thereby formed by the latching hooks  59 ,  60  as well as the first and second circumferential edge  57 ,  58 . Furthermore, the connecting member  55  has formed a connecting recess  61 . The latching hooks  59  are arranged horizontally in the connecting recesses  61  in such a way that the connecting member  55  and the second combustion air line  53  are form-fittingly connected to each other. With the aid of the latching connection  56  and the form-fitting connection, the internal thread of the connecting member  55  can be brought into engagement with the external thread of the second exhaust pipe  10  in such a way that the coupling connection  18  can be established or removed by actuating the second combustion air line  53 , i.e. by rotary movement. When the external second combustion air line  53  is rotated, the connecting member  55  consequently rotates with it, wherein the connecting member  55  establishes the coupling connection  18  by its rotation. 
     The above is a described exhaust pipe system  8  according to the invention for conducting exhaust gas from a combustion device  5  to an exhaust system  7 . The exhaust pipe system  8  comprises the first exhaust pipe  9 , which has the inlet end  12  and the outlet end  14 , wherein the outlet end  14  is formed to be connectable to the exhaust system  7 . Furthermore, the exhaust pipe system  8  comprises the second exhaust pipe  10  formed with the first line end  15  and the second line end  16 . The second line end  16  is formed so that it can be connected to the combustion device  5 . The inlet end  12  of the first exhaust pipe  9  can be connected to the first line end  15  of the second exhaust pipe  10  via the detachable coupling connection  18 , wherein within the first exhaust pipe  9  the locking member  11  is arranged to be movable between the closed position closing the passage  21  and the open position opening the passage  21 . When the coupling connection  18  is removed, the locking member  11  is automatically arranged in the closed position. The second exhaust pipe  10  has the actuating member  40 , which, when the coupling connection  18  has been established, urges the locking member  11  into the open position. The locking member  11  is formed as a rotatably mounted and axially displaceable butterfly valve  23 , wherein the actuating member  40  moves the butterfly valve  23  in the direction of the outlet end  14  when moving into the open position. 
     The invention described above is, of course, not limited to the embodiments described and depicted. It is evident that numerous modifications can be made to the embodiments shown in the drawing, which are obvious to the skilled person according to the intended application, without leaving the scope of the invention. For example, the detachable coupling connection can also be designed as a latching connection. The invention includes everything that is contained in the description and/or depicted in the drawing, including anything that, deviating from the concrete design examples, is obvious to the person skilled in the art.