INFRARED RADIATOR AND METHOD OF ASSEMBLING SAME

Abstract

An infrared radiator for the heat treatment of a material web has an incandescent body with a flow-receiving surface that is subjected to a flow of a gas-air mixture supplied to the infrared radiator and heated by combustion of the gas-air mixture. The incandescent body is manufactured as a sheet material formed of a multiplicity of threads and connecting elements that at least indirectly connect the threads to one another. The connecting elements at least partially engage around the threads and thus connect them at least indirectly to one another. The connecting elements are configured in such a way that they may be detached from the connection with the threads, preferably by hand, while breaking up the sheet material.

Claims

1-15. (canceled)

16. An infrared radiator for the heat treatment of a material web, the infrared radiator comprising: an incandescent body having a flow-receiving surface disposed to be impinged by a gas-air mixture supplied to the infrared radiator and to be heated by a combustion of the gas-air mixture; said incandescent body being manufactured as a sheet material formed of a multiplicity of threads and connecting elements that, at least indirectly, connect said threads to one another; said connecting elements at least partially engaging around said threads and connecting said treads to one another at least indirectly; said connecting elements being configured to enable a connection of said connecting elements with said threads to be detached while breaking up said sheet material.

17. The infrared radiator according to claim 16, wherein said connecting elements and said threads are detachable by hand for manually breaking up said sheet material.

18. The infrared radiator according to claim 16, wherein said connecting elements are configured to enable a reconnection thereof with said threads to thereby form the sheet material.

19. The infrared radiator according to claim 16, wherein at least one of said connecting elements or said threads is configured so that neither said connecting elements nor said threads are destroyed when said sheet material is either broken up or manufactured.

20. The infrared radiator according to claim 16, wherein said connecting elements are configured to hold said threads together in a loss-proof manner.

21. The infrared radiator according to claim 16, wherein individual said threads are configured for detachment from a connection between said threads by a longitudinal and/or rotary movement along a longitudinal axis thereof.

22. The infrared radiator according to claim 16, wherein said connecting elements are formed as threads, and both said connecting elements and said threads are formed spirally, thus defining the sheet material as a spiral braid, respectively such that a connecting element connects two directly adjacent threads to one another by engaging said directly adjacent threads into each other.

23. The infrared radiator according to claim 22, wherein said connecting elements are formed as threads having an identical outer contour to the threads that connect them.

24. The infrared radiator according to claim 16, wherein: said sheet material is a woven fabric comprising threads serving as warp threads that are interwoven with threads serving as weft threads; said connecting elements are threads being either warp threads or weft threads and said connecting elements are arranged respectively between two identical threads in the form of warp threads or weft threads; and said threads have a wave-shaped outer contour and said connecting elements have a rectilinear outer contour.

25. The infrared radiator according to claim 24, wherein the woven fabric is constructed in the manner of a plain weave, so that the directly adjacent threads that serve as weft threads weave alternately through the threads serving as warp threads, along different weaving paths.

26. The infrared radiator according to claim 16, wherein at least one of said threads or said connecting elements are made of a comparatively flexurally rigid material.

27. The infrared radiator according to claim 26, wherein said threads and/or said connecting elements are made of ceramic material.

28. The infrared radiator according to claim 16, wherein said flow-receiving surface is at least one delimiting side of said incandescent body.

29. The infrared radiator according to claim 16, wherein said infrared radiator has a burner plate and said incandescent body is arranged behind said burner plate in a flow direction of the gas-air mixture.

30. The infrared radiator according to claim 29, wherein said incandescent body directly adjoins said burner plate viewed in the flow direction of the gas-air mixture.

31. The infrared radiator according to claim 16, wherein said incandescent body is formed of a plurality of layers of said sheet material arranged on top of one another.

32. The infrared radiator according to claim 16, wherein at least one of said threads or said connecting elements are individually manufactured.

33. The infrared radiator according to claim 32, wherein said at least one of said threads or said connecting elements are manufactured by primary forming.

34. A method of assembling the infrared radiator according to claim 16, the method comprising the following steps: a) providing individual threads and connecting elements; b) at least indirectly connecting individual threads to one another with at least one connecting element in such a way that two directly adjacent threads are detachably interconnected directly or indirectly by engaging the connecting element in the threads to produce a sheet material.

35. The method according to claim 34, which comprises connecting the threads and the connecting element so that the sheet material may be disassembled by disconnecting the threads and the connecting element by hand.

Description

[0037] The invention is described in greater detail below with reference to the drawings, without restricting the invention's generality. The drawings show the following:

[0038] FIG. 1 a schematic, partially cut-away and not-to-scale representation of one embodiment of an infrared radiator;

[0039] FIGS. 2a and 2b spatial representation of two respectively different embodiments of the incandescent bodies according to the invention;

[0040] FIG. 3 a highly schematized representation of a drying arrangement in a three-dimensional view according to one embodiment.

[0041] FIG. 1 shows an exemplary embodiment of the invention in a schematic, partially cut-away view through a plane that is perpendicular to the material web and parallel to the running direction (indicated by the arrow). The drawing shows an infrared radiator 1, which may be part of a drying arrangement (see FIG. 2). During normal operation, the infrared radiator 1 is arranged at a distance from the material web 8, for example above it. The radiator forms a burner that is arranged in a housing 11.1. This housing has, for example, a rear wall and a plurality of side walls. The rear wall is located on the side (rear side) of the infrared radiator 1 facing away from the material web 8. An opening 2 is provided in this wall, through which a fuel, for example gas and air (an ignitable, combustible gas-air mixture) may enter a mixing chamber 3. The corresponding supply lines outside the infrared radiator 1 are not shown in detail. The mixing chamber 3 is delimited on one side by a gas-permeable burner plate 4 and on the other side by the housing 11.1, here the rear wall thereof. The gas-air mixture flows into the burner plate 4 at a flow-receiving surface corresponding to the rear side of the infrared radiator 1 and passes through the gas-permeable burner plate 4, to be combusted. From there the mixture flows into a combustion chamber 5. This chamber is delimited or formed jointly by the burner plate 4 and an incandescent body 6. The gas-permeable burner plate 4 may be said to separate the mixing chamber 3 from the combustion chamber 5. In the latter chamber, the gas-air mixture ignites. The heat released heats the incandescent body 6 until this body begins to glow. As a result, the body emits infrared rays toward the material web 8 to be dried. Both the burner plate 4 and the incandescent body 6 have a slab-shaped or cuboidal outer contour. In principle, a different outer contour would be possible. In this case, the flow-receiving surface of the incandescent body 6 corresponds to the flow-receiving surface of the burner plate 4. In other words, the two flow-receiving surfaces are the same. They correspond in this case to the clear width of the housing 11.1 that accommodates both the burner plate 4 and the incandescent body 6.

[0042] Irrespective of the embodiment shown, the infrared radiator 1 with its incandescent body 6 faces the material web 8; in the case shown, it does so in such a way that the incandescent body 6 runs parallel thereto. However, this need not necessarily be the case. The infrared radiator 1 may also run at an angle thereto. As shown in FIG. 1, the burner plate 4 and the incandescent body 6 are connected in series, viewed in the flow direction of the gas-air mixture. The incandescent body 6 is arranged downstream of the burner plate 4.

[0043] According to the embodiment of FIG. 1, the incandescent body 6 is designed as a gas-permeable regular grid. This grid may be formed by at least one sheet material. This structure is made up of a multiplicity of threads that delimit the openings of the grid. Consequently, the gas-air mixture passing through the burner plate 4 may also flow through all openings of the incandescent body 6 (simultaneously).

[0044] The incandescent body 6 is arranged at a distance from the burner plate 4, viewed in the flow direction of the gas-air mixture or the combustion products thereof. In other words, the combustion chamber 5 is formed by the space jointly delimited by the burner plate 4 and the incandescent body 6. The burner plate 4 and incandescent body 6 are arranged parallel to each other with regard to their flow-receiving surfaces or delimiting sides.

[0045] Although not shown in the drawings, it would be possible for the incandescent body 6 to directly abut the burner plate 4. This means that both are arranged without distance from each other and preferably parallel to each other.

[0046] Irrespective of the embodiment shown, it would be conceivable in principle, for example to provide a plurality of layers of an incandescent body 6, or more precisely several layers of sheet materials, which could be arranged at a distance from the burner plate 4 in the flow direction of the gas-air mixture or the resulting combustion products.

[0047] FIGS. 2a and 2b respectively show a spatial representation of two different embodiments of the incandescent body 6 according to the invention as a sheet material.

[0048] The sheet materials are formed from a multiplicity of threads 15 and connecting elements 16. Both incandescent bodies 6 are designed in such a way that the sheet materials may be both assembled and disassembled by hand without destroying individual threads 15 or connecting elements 16 in the process.

[0049] According to the embodiment of FIG. 2a, the sheet material is designed as a spiral braid. In addition, the threads 15 and the connecting elements 16 are identical, in the form of spirals. Both the longitudinal central axes of the threads 15 and those of the connecting elements 16 run parallel to each other over the entire spatial extent of the resulting sheet material. Threads 15 that are directly adjacent to one another (i.e. the threads 15 respectively arranged to the left and right of each connecting element 16) are thus each connected to a connecting element 16, which is likewise designed as a thread, in such a way that the spirals thereof are screwed into one another. Connecting elements 16 and threads 15 are respectively mounted to each other in an articulated manner at the shared intersection points.

[0050] This interlocking of the connecting elements 16 and threads 15 results in a loss-proof structure. This is because the direction of assembly or disassembly here runs in the direction of the longitudinal central axes of the connecting elements 16 and threads 15. This direction lies in the plane spanned by the sheet material, which here is also parallel to the material web 8. If the respective abutting ends of the outer contour of the resulting sheet material or incandescent body 6 are held in the housing 11.1 of the infrared radiator 1, they are prevented from falling out in the direction perpendicular to the material web 8.

[0051] The embodiment of FIG. 2b shows an incandescent body 6 in the form of a woven sheet material. Here, two directly adjacent threads 15.1 that are designed as weft threads weave the same weaving path through the warp threads, perpendicular to threads 15.2 that act as warp threads. A respective connecting element 16, which is likewise designed as a thread, is in this case arranged between mutually-adjacent threads 15.1. While the threads 15.1 and 15.2 have an undulating outer contour, the outer contour of the connecting elements 16 follows a straight line.

[0052] Irrespective of the embodiment shown, the threads 15 as well as the connecting elements 16 may be made of a comparatively flexurally rigid material, such as a ceramic. In this case, threads 15 and/or connecting elements 16 may be produced individually by primary forming. In this case, the methods mentioned above for manufacturing such sheet materials, such as weaving, may no longer be used. In this case, the sheet material must be assembled individually by hand, i.e. thread by thread, connecting element by connecting element. According to the embodiment of FIG. 2b, the threads 15.1 and 15.2, which serve as weft threads and warp threads, are laid crosswise, for example over the desired width. In the above example, this is done in the manner of a plain weave. Consequently, first, mutually-adjacent threads 15.1 that serve as weft threads take the same weaving path through the warp threads 15.2, i.e. both are alternately above and in turn below the threads 15.2 that serve as warp threads. In contrast, directly adjacent threads 15.2 that serve as warp threads always weave a mutually-different weaving path through the threads 15.1 that are designed as weft threads: While one thread 15.2 runs above the corresponding thread 15.1, the thread 15.2 directly adjacent thereto weaves below the corresponding thread 15.1.

[0053] Put differently, during assembly, the threads 15.1 and 15.2, without the connecting elements 16, initially form a scrim together. In the next step, a respective connecting element 16 is insertedbetween two neighborsinto each of the cavities formed jointly by the threads 15.2 that serve as warp threads, parallel to the threads 15.1 that serve as weft threads. These themselves become weft threads, in this case weft threads that are straight and not undulating. The respective connecting element 16 then indirectly interlocks the threads 15.1 and 15.2 that are designed as weft and warp threads. Put differently, the initial scrim becomes a self-supporting woven fabric. In this case, the assembly may be done by hand. Here, too, the assembly and disassembly plane lies in the extension plane of the incandescent body 6 and thus is parallel to the material web 8. This prevents individual threads 15 or connecting elements 16 from falling out toward the material web 8. Even if a thread 15 or connecting element 16 breaks, it is still sufficiently secured to the sheet material due to the multiplicity of intersection points, so that it is prevented from falling onto the material web 8. This applies analogously to the embodiment of FIG. 2a.

[0054] In principle, the connecting elements 16 could lock the threads 15.1 and 15.2 together in the manner of warp threads.

[0055] Irrespective of the embodiments shown, the increased surface area of the incandescent body 6 may considerably increase the radiation efficiency due to the wavy or spiral outer contour of the threads 15 or the connecting elements 16. This is achieved by increasing the surface area for the combustion of the gas-air mixture due to the selected outer contour, which results in a higher energy absorption from the combustion products of the gas-air mixture. This may also reduce the proportion of nitrogen oxides and carbon monoxide in the combustion products.

[0056] FIG. 3 shows a possible embodiment of a drying arrangement 11 according to the invention. This may be part of a machine for manufacturing or treating a material web. The drying arrangement 11 here is arranged behind a coating or binder section (not shown) of the machine, in the running direction of the material web 8. Within this section, a coating color or binder is applied to the material web 8. As a result of this application, the material web 8 absorbs moisture and must therefore be dried, or the binder must be cured. This is done in the drying arrangement 11.

[0057] The drying arrangement 11 comprises one or, as shown here, a plurality of infrared dryers 12, each of which respectively has a multiplicity of infrared radiators 1 that serve as surface radiators and are preferably arranged parallel to the material web 8. In addition, the drying arrangement 11 also has a plurality of air dryers 13. In the present case, an infrared dryer 12 is respectively downstream of an air dryer 13 when viewed in the running direction of the material web 8, and so forth. Such an infrared dryer 12 and air dryer 13 are respectively referred to as a combination dryer 14. Four combination dryers 14 are furnished, arranged one behind the other in the running direction of the material web 8 to be dried. These combination dryers are, in this case, arranged directly abutting one another. Consequently, when the material web 8 to be dried leaves a first combination dryer 14, it immediately reaches the following combination dryer 14 viewed in the running direction. All combination dryers 14 are set up in such a way that, viewed in the running direction of the material web, drying occurs by infrared radiation from the associated infrared dryer 12, then by convection through the corresponding air dryer 13, by heat radiation and so on alternatingly. As soon as the material web 8 has left the first combination dryer 14 as viewed in the running direction of the web, it is transferred to the second combination dryer 14. There in turn, as viewed in its running direction, the web is first dried by the corresponding infrared dryer 12 and then by the corresponding air dryer 13. In other words, an air dryer 13 assigned to the first combination dryer 14 is arranged between an infrared dryer 12 of a first combination dryer 14 in the running direction and an infrared dryer 12 of another combination dryer 14 immediately following it in the running directionviewed respectively in the running direction of the material web 8 through the drying arrangement 11. One could also say that the material web 8 is dried along the drying arrangement 11 alternatingly by heat radiation, then by convection, again in turn by heat radiation and so on.

[0058] The infrared dryer 12 of a respective combination dryer 14 may be designed as a gas-heated infrared dryer according to the invention. In this case, the infrared dryer 12 may comprise one or more infrared radiators 1 according to the invention (see FIG. 1). The combustion products (exhaust gases) that the infrared radiators 1 generate may then be extracted from the infrared dryer 12 via one or more suction nozzles 12.1 associated with the infrared dryer 12, only one of which is indicated here in a purely schematic manner. The at least one suction nozzle 12.1 may be arranged inside a housing that surrounds the infrared dryer 12.

[0059] The respective air dryer 13 may comprise one or more blowing nozzles 13.1, of which only one is shown here, likewise in a purely schematic manner. The at least one blowing nozzle 13.1 serves, among other things, to supply heated air to the material web 8 for drying. For this purpose, the at least one blowing nozzle 13.1 may be connected to a fresh air supply (not shown) in a flow-conducting manner. In addition, a flow-conducting connection may be furnished between the at least one suction nozzle 12.1 and the at least one blowing nozzle 13.1 of the same combination dryer 14. The thermal energy contained in the exhaust gas of the infrared dryer 12 may be used to heat the fresh air or to dry the material web 8 using the thermal energy of the exhaust gas of the respective infrared dryer 12.