OXIDATION OVEN

Description

[0001] The invention relates to an oxidation furnace for the oxidative treatment of fibers, in particular for the production of carbon fibers, with a) a housing which is gas-tight except for through-openings for, among other things, the fibers; b) a process chamber located in the interior of the housing; c) deflection rollers which guide the fibers as a fiber carpet lying next to one another in a serpentine manner through the process chamber, wherein the fiber carpet spans a plane between opposite deflection rollers; d) an atmosphere device with which a hot working atmosphere can be generated and which comprises an injection device with at least one outlet window through which hot working atmosphere can be injected into the process chamber between two adjacent planes of the fiber carpet; wherein e) the working atmosphere enters the process chamber via a flow guide device; and f) the flow guide device comprises replaceable flow guide elements with flow passages which can be detachably and / or movably mounted in front of the outlet window on the injection device.

[0002] Oxidation furnaces of the type mentioned above are known, for example, from EP 2 738 292 A1, JP 2007-247130 A or JP 2008-202158 A.

[0003] In such commercially available oxidation furnaces, the injection device comprises, for example, several injection boxes from which the working atmosphere enters the process chamber. An outlet window is formed by the outlet wall of each injection box, which has a plurality of flow passages. These flow passages accordingly define a flow guide device; the flow of the working atmosphere is influenced by their arrangement and geometry.

[0004] During operation of the oxidation furnace, contaminants, particularly silica and fiber debris, accumulate in the flow passages. Therefore, at least the flow openings must be cleaned at regular intervals to maintain a reproducible flow of the working atmosphere.

[0005] The injection boxes are permanently installed in the furnace, and their flow passages are usually difficult to access. Furthermore, the fibers often have to be moved, at least on the deflection rollers, or sometimes even completely removed from the process chamber to ensure adequate cleaning.

[0006] Overall, the cleaning process is very time-consuming and labor-intensive, and therefore also costly.

[0007] It is therefore an object of the present invention to provide an oxidation furnace which takes this idea into account.

[0008] This object is achieved in an oxidation furnace of the type mentioned above in that g) access means are provided through which the flow guide element is accessible from outside the process chamber.

[0009] According to the invention, it was recognized that this avoids work in the process chamber and, in an otherwise permanently installed injection device, at least the flow passages can be provided by replaceable flow guide elements, which can be removed from the process chamber at any time for cleaning and replaced with uncontaminated flow guide elements. The contaminated and removed flow guide elements can then be cleaned somewhere other than the process chamber. This primarily eliminates work inside the furnace.

[0010] It is advantageous if the exit window extends essentially from a first longitudinal wall to an opposite second longitudinal wall of the housing. This allows the entire width of the oxidation furnace to be covered, and access is preferably provided from the longitudinal side of the oxidation furnace.

[0011] A flow guide element can preferably be mounted in a holding device.

[0012] In practice, it has proven advantageous if the holding device includes guide rails for a flow guide element, which extend along the upper and lower edges of the exit window. This ensures secure guidance of the flow guide element, even if it is only handled from the long side of the oxidation furnace.

[0013] It is particularly advantageous if the access means are formed by a through-opening in one longitudinal wall of the housing or by two opposing through-openings in two opposing longitudinal walls of the housing. This is particularly simple to implement structurally.

[0014] Preferably, the flow guide element is designed as an elongated plate, which can completely cover the outlet window of the injection device. This elongated plate can preferably be a steel sheet, for example. In this case, a respective through-opening in just one longitudinal wall of the oxidation furnace is sufficient for exchanging flow guide elements.

[0015] Alternatively or additionally, two or more flow guide elements in the form of flow guide modules can be provided, two or more of which cover an exit window. These then cooperate, for example, with opposing through-openings in the longitudinal walls of the oxidation furnace, so that at least one of the flow guide modules is guided through a respective through-opening.

[0016] Alternatively or additionally, the flow guide element can also be formed by a winding belt that is stretched between a source roller and a take-up roller along the exit window and is movable so that a portion of the winding belt covers the exit window. Such a winding belt can be guided past the exit window intermittently or continuously.

[0017] If the rolls are arranged outside the housing and the winding tape is guided through two opposite through openings in two opposite longitudinal walls of the housing, the rolls can be advantageously handled without the need for access to the process space.

[0018] Advantageously, a cleaning device can be provided through which the winding strip is passed after leaving the process chamber. This allows cleaning to be performed in the furnace environment, and the cleaned winding strip can be reused in a more direct cycle if necessary.

[0019] Embodiments of the invention are explained in more detail below with reference to the drawings, in which: Figure 1 shows a vertical section through an oxidation furnace for producing carbon fibers in the longitudinal direction of the furnace with an atmosphere device with which a hot working atmosphere can be generated and blown into the process chamber, as well as a flow guide device for homogenizing the atmosphere flow; Figure 2 shows a perspective detail with a view of an injection device of the atmosphere device and associated flow guide elements of the flow guide device; Figure 3 shows a section of a cross section of the oxidation furnace with a view of the injection device with a flow guide device according to a first embodiment; Figure 4 shows one of the Figure 3 corresponding section with a flow guide device according to a second embodiment; Figure 5 shows the Figures 3 and 4 corresponding section with a flow guide device according to a third embodiment; Figure 6 a section similar to the Figures 3 to 5 with a flow guiding device according to a fourth embodiment; Figure 7 shows a section of Figure 1 with a view from above of the flow guide device Figure 6 ; Figure 8one of the Figure 7 corresponding section with a further modified flow guide device.

[0020] First, the Figure 1 which shows a vertical section of an oxidation furnace used for the production of carbon fibres and is designated overall by 10.

[0021] The oxidation furnace 10 comprises a housing 12 which defines a passage space forming the interior 14 of the oxidation furnace 10 by a ceiling wall 12a and a bottom wall 12b and two vertical longitudinal walls 12c, 12d, of which Figure 1 only the longitudinal wall 12d located behind the cutting plane can be seen.

[0022] At each of its ends, the housing 12 has an end wall 16a, 16b, wherein in the end wall 16a, from top to bottom, there are alternating through-openings in the form of horizontal inlet slots 18 and outlet slots 20, and in the end wall 16b, from top to bottom, there are alternating through-openings in the form of horizontal outlet slots 20 and inlet slots 18, which for the sake of clarity are not all identified by reference numerals. Fibers 22 are guided into and out of the interior space 14 through the inlet and outlet slots 18 and 20, respectively. The inlet and outlet slots 18, 20 generally form passage areas of the housing 12 for the carbon fibers 22. Apart from these through-openings and those explained further below, the housing 12 of the oxidation furnace 10 is gas-tight.

[0023] The interior space 14 is in turn divided into three areas in the longitudinal direction and comprises a first pre-chamber 24, which is arranged directly next to the end wall 16a, a second pre-chamber 26, which is directly adjacent to the opposite end wall 16b, and a process space 28 located between the pre-chambers 24, 26.

[0024] The pre-chambers 24 and 26 thus simultaneously form an inlet and outlet lock for the fibers 22 into the interior space 14 and the process space 28, respectively.

[0025] The fibers 22 to be treated are fed into the interior 14 of the oxidation furnace 10 in a parallel manner as a kind of fiber carpet 22a. For this purpose, the fibers 22 enter the first prechamber 24 from a first deflection area 30, which is located next to the end wall 16a outside the furnace housing 12, through the uppermost entrance slot 18 in the end wall 16a. The fibers 22 are then guided through the process chamber 28 and through the second prechamber 26 to a second deflection area 32, which is located next to the end wall 16b outside the furnace housing 12, and from there back again.

[0026] Overall, the fibers 22 pass through the process chamber 28 in a serpentine fashion over deflection rollers 34 arranged one after the other from top to bottom, only two of which bear a reference symbol. Between the deflection rollers 34, the fiber carpet 22a formed by the plurality of adjacent fibers 22 spans a plane. The fibers can also run from bottom to top, and there can also be more or fewer planes than in Figure 1 shown.

[0027] After passing through the entire process chamber 28, the fibers 22 exit the oxidation furnace 10 in the present embodiment through the lowest exit slot 20 in the end wall 16a. Before reaching the uppermost entrance slot 18 in the end wall 16a and after leaving the oxidation furnace through the lowest exit slot 20 in the end wall 16a, the fibers 22 are guided outside the furnace housing 12 via further guide rollers 36.

[0028] Under process conditions, the process chamber 28 is flowed through by a hot working atmosphere 38, which is generated by an atmosphere device 40. Generally speaking, a hot working atmosphere 38 can be generated with the atmosphere device 40 and blown into the process chamber 28, which flows through the process chamber 28 under process conditions.

[0029] In the present embodiment, there are two counter-rotating hot air streams 38a, 38b, each with a main flow direction indicated by an arrow, whereby the process chamber 28 is fluidically divided into two process chamber sections 28a, 28b. An injection device 42 is arranged in the central region of the process chamber 28, and an extraction device 44 is arranged in each of the two outer end regions of the process chamber 28, each of which is adjacent to the prechambers 24, 26.

[0030] Starting from the extraction devices 44, the air is drawn into a Figure 1 conveyed to the air guide chamber 46 located behind the plane of the drawing, in which it is processed and conditioned in a manner not of further interest here, with its temperature being adjusted in particular by heating units not specifically shown.

[0031] Two outlets 48 are also provided in the area of the air guide chamber 46. These outlets can be used to remove the gas or air volumes that either arise during the oxidation process or enter the process chamber 28 as fresh air through an air supply device (not specifically shown), thus maintaining the air balance in the oxidation furnace 10. The removed gases, which may also contain toxic components, are fed to thermal afterburning. The heat recovered in this process can be used at least to preheat the fresh air supplied to the oxidation furnace 10.

[0032] From the air guide chamber 46, the air passes to the injection device 42. This discharges the now circulated and conditioned air into the process chamber 28. During the serpentine passage of the fibers 22 through the process chamber 28, they are now surrounded by hot, oxygen-containing air and oxidized in the process.

[0033] To ensure that the working atmosphere 38 flows through the process chamber 28 in a largely homogeneous manner, the working atmosphere enters the process chamber 28 via a flow guide device 50, which will be discussed in more detail below. The flow guide device 50 ensures that the flow of the working atmosphere 38 between adjacent fiber carpets 22a is largely uniform across the furnace cross-section, so that there are no significant differences at different levels, particularly in the flow velocities and the temperature distribution across the process chamber 28.

[0034] In the present embodiment, the working atmosphere 38 is discharged into the process chamber sections 28a, 28b in a counter-flow direction towards the deflection areas 30 and 32. In these, the air streams 38a, 38b flow in opposite directions to the respective extraction devices 44, which in Figure 1 This is illustrated by corresponding arrows. In total, two circulating air circuits are thus closed, and the oxidation furnace 10 is operated according to the aforementioned "center-to-end" flow principle. However, all other known flow principles can also be implemented.

[0035] The injection device 40 comprises a plurality of injection boxes 52, each defining a fluidically open outlet window 54 of the injection device 40, each extending transversely to the longitudinal direction of the furnace. The outlet windows 54 point in the direction of the opposite extraction device 44. The extraction devices 44, in turn, each comprise a plurality of extraction boxes 56, which define fluidically open inlet windows 58 of the extraction devices 54, which point in the direction of the respective opposite injection device 42.

[0036] "Fluidically open" means that a gas flow can flow out of the injection device 40 or into the extraction device 44 through the respective windows 54 or 58. For this purpose, the windows 54, 58 can be formed, for example, by omitting a respective wall in the injection boxes 52 or the extraction boxes 56. If necessary, a wall of an injection box 52 or an extraction box 56 can also be provided with flow passages.

[0037] As in Figure 2 As can be seen, the flow guiding device 50 comprises flow guiding elements 60 with flow passages 62, wherein at least one flow guiding element 60 is arranged in front of an outlet window 54 of the injection device 42, ie in the present embodiment in front of an outlet window 54 of an associated injection box 52. Only one flow guiding element 60 and only one flow passage 62 thereof is provided with a reference symbol.

[0038] At least the flow openings 62 of the flow guide device 50 must now be cleaned at regular intervals in order to reproducibly maintain the flow of the working atmosphere 38. For this purpose, the contaminants explained above, which are deposited on the flow passages 62 during operation of the oxidation furnace 10, are removed.

[0039] For this purpose, the flow guide elements 60 are each designed to be interchangeable and are mounted detachably and / or movably in front of a respective outlet window 54 on the injection device 42. For this purpose, the flow guide device 50 comprises a holding device 64, by means of which the flow elements 60 can be mounted detachably and / or movably.

[0040] The flow passages 62 of the flow guide elements 60 are traversed by the working atmosphere 38 before it enters the process chamber 28, influencing the discharge direction, the discharge velocity, and thus the flow pressure of the working atmosphere 38. The flow passages 62 of the flow guide elements 60 are dimensioned and arranged such that the overall flow of the working atmosphere 38 is homogenized across the furnace cross-section. The flow passages 62 can be identical but can also be different in their geometry, dimensions, and arrangement.

[0041] In Figure 3A first embodiment of the flow guide device 50 is illustrated. There, a flow guide element 60 is designed as an elongated plate 66 with flow passages 62, which is dimensioned such that it can completely cover an outlet window 54 of the injection device 40. The holding device 64 is formed by pairs of guide rails 68a, 68b for the flow guide elements 60, wherein one guide rail 68a runs at the upper edge and one guide rail 68b at the lower edge along an outlet window 54 of the injection device 42; each pair of rails 68a, 68b can accommodate a flow guide element 60. Figures 3 to 6 only the pair of rails 68a, 68b on the uppermost blowing box 52 is provided with reference symbols.

[0042] The guide rails 68a, 68b extend through a longitudinal wall, in the present example through the first longitudinal wall 12c of the furnace housing 12, in which a through opening in the form of a through slot 70 is provided at the level of each injection box 52, so that a flow guide element 60 can be pushed through the longitudinal wall 12c into the guide rails 68a, 68b and in front of the associated outlet window 54 into the interior 14 of the oxidation furnace 10 and can be removed therefrom again.

[0043] Generally speaking, the through slots 70 are an example of access means through which a flow guide element 60 is accessible from outside the process chamber. In a modification not specifically shown, a door may also be provided in a longitudinal wall 12c or 12d, extending over the required height of the oxidation furnace 10, so that all flow guide elements 60 are accessible when the door is open.

[0044] In Figure 3The uppermost flow guide element 60 is shown in a working position in front of the outlet window 54 of the uppermost injection box 52. The middle flow guide element 60 assumes an intermediate position in which it is inserted approximately halfway into the guide rails 68a, 68b and covers approximately half of the outlet window 54. This intermediate position is passed through both during insertion and removal of the flow guide element 60. The Figure 3 The lower flow guide element 60 is removed from the interior 14 of the oxidation furnace 10 and can be replaced there by a non-contaminated flow guide element 60, which can then be moved into the working position in front of the outlet window 54 of the Figure 3 lower injection box 52, whereby a contaminated flow guide element 60 is exchanged for a flow guide element 60 free of contaminants.

[0045] In order for the flow guide elements 60 to be manually removed from the interior 14 of the oxidation furnace 10 by a maintenance person and also pushed back into its interior 14, the flow guide elements 60 have a handle 72 at one end. There are also sealing means not specifically provided with a reference symbol, by means of which the through-slot 70 is sealed when the flow guide element 60 is pushed in, so that no furnace atmosphere can penetrate to the outside.

[0046] Figure 4illustrates a second embodiment of the flow guide device 50. There, flow guide elements 60 are provided in the form of plate-shaped flow guide modules 74 with flow passages 62, two of which cover an outlet window 54 next to each other, and on whose handles 72, again not specifically provided with a reference symbol, sealing means are provided. In the drawing and below, the flow guide modules are referred to as flow guide modules 74a and 74b. Through slots 70 are provided not only in the first longitudinal wall 12c of the oxidation furnace 10, but also in its opposite second longitudinal wall 12d, and there at the same height.In this way, a first flow guide module 74a can be pushed through the through slot 70 in the first longitudinal wall 12c and a second flow guide module 74b can be pushed through the through slot 70 in the second longitudinal wall 12d of the housing 12, so that a pair of flow guide modules 74a, 74b, as flow guide elements 60, covers a respective outlet window 54 of the injection device 42. The guide rails 68a, 68b also extend through the through slots 70 in the longitudinal wall 12d, as in the longitudinal wall 12c.

[0047] In Figure 4 The two flow guide modules 74a, 74b are shown in the uppermost injection box 52 in a working position in front of its outlet window 54, in which they together form the flow guide element 60. The flow guide modules 74a, 74b each assume an intermediate position in the middle injection box, in which they each protrude through the through slots 70. The Figure 4The lower flow guide modules 74a, 74b are removed from the interior 14 of the oxidation furnace 10 and can be exchanged there for a non-contaminated flow guide module 74a or 74b, which can then be moved into the working position in front of the outlet window 54 of the Figure 4 lower blowing box 52.

[0048] Figure 5shows a third embodiment of the flow guiding device 50, in which flow guiding elements 60 are formed in the form of flow guiding modules 74, of which more than two cover an exit window 54. In the present embodiment, four plate-shaped flow guiding modules 74 are required for this purpose, with only some flow modules 74 bearing a reference numeral. The plurality of flow guiding modules 74 are exchanged at intervals during operation, for which purpose they are displaced in an intermittent passage from the longitudinal wall 12d in the direction of the longitudinal wall 12c along the guide rails 68a, 68b. For this purpose, in a first, in Figure 5In the variant illustrated for the middle injection box 52, a flow guide module 74 is attached to the through slot 70 on the side of the longitudinal wall 12d and pushed into the guide rails 68a, 68b. As a result, the flow guide module 74 located at the opposite end on the longitudinal wall 12c is pushed out of the guide rails 68a, 68b through the through slot 70 there and can be removed by a maintenance person.

[0049] In a second, in Figure 5 In the variant illustrated in the lower injection box 52, all flow guide modules 74 are simultaneously pushed out of the guide rails 68a, 68b with the aid of a tool 76 and replaced as a set with uncontaminated flow guide modules 74.

[0050] In this embodiment, the slots 70 are covered by sealing means in the form of movable flaps 78, which may also be present in all other described embodiments. Instead of the flaps 78, other sealing means in the form of, for example, brush seals, lamellar seals, or the like may also be present. Such seals may also be present in the embodiments according to the Figures 3 and 4 be present. Replaceable plugs can also be used.

[0051] The Figures 6 and 7show a fourth embodiment of the flow guide device 50. There, the outlet window 54 of an injection box 52 is covered by a section 80 of a winding band 82 with flow passages 62, which thus defines a flow guide element 60. The winding band 82 is complementary in its dimensions to the outlet windows 54 of the injection device 42 and is guided through two opposite through slots 70 in the longitudinal walls 12c, 12d of the furnace housing 12. Thus, through slots 70 in the longitudinal wall 12d each form an inlet opening, and through slots 70 in the opposite longitudinal wall 12c each form an outlet opening for an associated winding band 82.

[0052] Outside the furnace housing 12 there is a rotatably mounted source roll 84, on which the winding tape 82 is held and from which the winding tape 82 is guided through the process chamber 28 to the opposite side of the furnace housing 12 to a take-up roll 86, which is also mounted outside the housing 12. Vertical axes of rotation of the respective source and take-up rolls 84 and 86 are in Figure 6 designated 84a and 86a, respectively. The winding belt 82 is thus stretched and movable between the two rollers 84, 86 along the exit window 54.

[0053] If the flow passages 62 of one of the winding tapes 82 are so contaminated that a replacement of the flow guide element 60 is appropriate, the winding tape 82 is unwound from the source roll 84 so that the section 80 is moved out of the process chamber 28 and wound onto the take-up roll 86. A subsequent, clean section 80 of the winding tape 82 then defines a replaced flow guide element 60, which takes the place of the previous flow guide element 60 in the form of the previous winding tape section 80.

[0054] In Figure 6 For example, more winding tape 82 has already been unwound from the source roll 84 on the lower winding tape 82 than on the uppermost winding tape 82 running above it. Figure 7 shows this lower winding band 82.

[0055] In this variant, the winding belt 82 is moved intermittently. Alternatively, the winding belt 82 can also be moved continuously, as long as the resulting movement of the flow passages 62 does not undesirably affect the flow pattern of the working atmosphere 38.

[0056] The source rollers 84 and the take-up rollers 86 can each be driven by a motor or manually by a maintenance person to move the winding tape 82.

[0057] When the winding tape 82 has been completely unwound from the source roll 84, the now empty source roll 84 is replaced with a source roll 84 equipped with clean winding tape 82 and the now full take-up roll 86 is replaced with an empty take-up roll 86.

[0058] Figure 8shows a variant in which the winding belt 82, after leaving the process chamber 28, is guided through the longitudinal wall 12d of the furnace through a cleaning device 88 which is arranged between the passage slot 12d and the take-up roller 86.

[0059] The winding belt 82 is deflected to the cleaning device 88 via a deflection roller 90. The winding belt 82 can also enter the cleaning device 88 directly without a deflection roller 90.

[0060] In the cleaning device 88, the winding tape 82 is freed from impurities and deposits in a continuous intermittent pass, so that the take-up roll 86 becomes the source roll 84 when the winding tape 82 is completely unwound from the original source roll 84.

[0061] In practice, the flow guide elements 60 are made of sheet steel, which can withstand the furnace atmosphere. The winding band 82 can, for example, be made of appropriately flexible spring steel.

[0062] Deposits also form at the inlet windows 58 of the suction devices 44, which increasingly restrict the flow path over time and which must be removed at regular intervals.

[0063] The above explanations regarding the injection device 42 therefore also apply mutatis mutandis to the extraction devices 44. Over time, impurities also accumulate there, which must be removed at regular intervals. Each extraction device 44 is assigned an extraction guide device 92, which is only Figure 1are provided with a reference symbol and through which the working atmosphere flows into the respective extraction device 44. In front of the inlet windows 58 of the extraction devices 44, corresponding replaceable flow elements can now be provided in an analogous manner, which can be replaced and cleaned at the appropriate time.

[0064] Several embodiments of the flow guiding elements 60 can also be implemented in a flow guiding device 50, wherein different flow guiding elements 60 are then used between each two levels of the fiber carpet 22a.

Claims

1. An oxidation furnace for the oxidative treatment of fibers, in particular for producing carbon fibers, the oxidation furnace having a) a housing (12) which except for passage openings (18, 20, 70) for the fibers (22), inter alia, is gas tight; b) a process chamber (28) which is located in the interior (14) of the housing (12); c) deflection rollers (34) which guide the fibers (22) in a serpentine manner such that they lie beside one another in the form of a fiber carpet (22a) through the process chamber (28a), wherein the fiber carpet (22a) defines a plane between respective mutually opposite deflection rollers (34); d) an atmosphere generating installation (40), by way of which a hot operating atmosphere (38) is generatable, and which comprises a blower installation (42) having at least one exit window (54) through which hot operating atmosphere is capable of being blown into the process chamber (28) between two adjacent planes of the fiber carpet (22a); wherein e) the operating atmosphere (38) reaches the process chamber (28) by way of a flow directing installation (50), and f) the flow directing installation (50) comprises replaceable flow directing elements (60) having flow passages (62) which are mountable in a releasable and / or movable manner in front of the exit window (54) on the blower installation (42); characterized in that g) access means by way of which the flow directing element (60) is accessible from outside the process chamber (28) are provided.

2. The oxidation furnace as claimed in claim 1, characterized in that the exit window (54) extends substantially from a first longitudinal wall (12c) to an opposite second longitudinal wall (12d) of the housing (12).

3. The oxidation furnace as claimed in claim 1 or 2 characterized in that a flow directing element (60) is mountable in a holding installation (64).

4. The oxidation furnace as claimed in claim 3, characterized in that the holding installation (64) comprises guide rails (68a, 68b), extending along the upper and lower peripheries of the exit window (54), for a flow directing element (60).

5. The oxidation furnace as claimed in one of claims 1 to 4, characterized in that the access means are configured by a passage opening (70) in a longitudinal wall (12c, 12d) of the housing (12), or by two mutually opposite passage openings (70) in two mutually opposite longitudinal walls (12c, 12d) of the housing (12).

6. The oxidation furnace as claimed in one of claims 1 to 5, characterized in that the flow directing element (60) is configured as an elongate plate (66) by way of which the exit window (54) of the blower installation (40) is completely coverable.

7. The oxidation furnace as claimed in one of claims 1 to 6, characterized in that two or a plurality of flow directing elements (60) in the form of flow directing modules (74) are present, two or a plurality of the latter covering one exit window (54).

8. The oxidation furnace as claimed in one of claims 1 to 7, characterized in that the flow directing element (60) is configured by a wound tape (82) which is stretched and movable along the exit window (54) between a source roll (84) and a take-up roll (86) such that a portion (80) of the wound tape (82) covers the exit window (54).

9. The oxidation furnace as claimed in claim 8, characterized in that the rolls (84, 86) are disposed outside the housing (12) and the wound tape (82) is guided through two mutually opposite passage openings (70) in two mutually opposite longitudinal walls (12c, 12d) of the housing (12).

10. The oxidation furnace as claimed in claim 8 or 9, characterized in that a cleaning installation (88) through which the wound tape (82) upon leaving the process chamber (28) is guided is present.