JP2006200065A - Flameproofing treatment furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flameproofing treatment furnace of carbon fiber precursor fiber strand having high operation efficiency of cleaning and capable of improving productivity. <P>SOLUTION: The flameproofing treatment furnace 2 has a heat-treating chamber 4 for feeding hot air to the vertical direction of a precursor fiber strand 6 for horizontally traveling the interior of the furnace and carrying out flameproofing treatment of the strand 6, an upper passage 10, a lower passage 12, a hot air-circulating load 14, an upper air-permeable plate 18 and a lower air-permeable plate 20. At least either one air-permeable plate of the upper air-permeable plate 18 and the lower air-permeable plate 20 is formed so as to be freely taken in and out the furnace by a slide mechanism to constitute the flameproofing treatment furnace 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a flameproofing furnace for flameproofing a fiber that is a precursor of a carbon fiber, and more particularly to a flameproofing furnace for a precursor fiber suitable for producing a carbon fiber excellent in productivity.

  In the carbon fiber manufacturing process, precursor fibers such as acrylic fibers are made flame resistant, and the obtained flame resistant fibers are carbonized to form carbon fibers. As a method for making the precursor fiber flame resistant, there is a method in which hot air is circulated in an oxidizing atmosphere and the precursor fiber is allowed to pass therethrough (see, for example, Patent Document 1). In this flameproofing method, the precursor fibers are usually fed into a flameproofing furnace as bundled strands.

  FIG. 6 is a schematic front sectional view showing an example of a conventional flameproofing furnace. In FIG. 6, reference numeral 82 denotes a flameproofing furnace, which travels in a heat treatment chamber 84 by forming a strand group (pass) in which a large number of strands 86 are horizontally arranged. The strands 86 forming this path are folded back by a predetermined set of folding rollers (not shown) disposed outside the heat treatment chamber 84 and repeatedly supplied to the heat treatment chamber 84.

  By passing a high-temperature oxidizing gas through the path in the vertical direction, the oxidation reaction of the strands 86 can be promoted, and the reaction heat of the strands 86 can be removed to produce flame-resistant fibers.

  Furnace walls 88a and 88b are provided on both sides in the width direction of the strand 86 running in the heat treatment chamber 84 to separate the inside from the outside. On the outside of one furnace wall 88 a, a hot air circulation path 94 that communicates with an upper flow path (hot air discharge side flow path) 90 and a lower flow path (hot air suction side flow path) 92 of the heat treatment chamber 84 separates the space portion 96. Is provided.

  The heat treatment chamber 84 and the upper flow path 90 are partitioned by an upper air-permeable plate 98. The heat treatment chamber 84 and the lower flow path 92 are partitioned by the lower air-permeable plate 100. A plurality of air holes are formed in the upper air permeable plate 98 and the lower air permeable plate 100.

  The hot air heated by the heater 102 provided in the hot air circulation path 94 is sent into the heat treatment chamber 84 from the upper flow path 90 of the heat treatment chamber 84 by a blower 104 such as a fan, and travels by forming the path here. The existing strand 86 is flameproofed. Next, the hot air passes through the lower flow path 92 and enters the hot air circulation path 94, through which it is repeatedly heated by the heater 102.

  While the hot air circulation is repeated in the flameproofing treatment of the strand 86, foreign matters such as strands and powder from the strand accumulate in the hot air. This foreign matter accumulates in the air holes of the upper air permeable plate 98 and / or the lower air permeable plate 100. As the foreign matter accumulates repeatedly, the resistance differential pressure before and after the air-permeable plate increases, the circulating air volume in the furnace decreases, and the strand cannot be stably flame-resistant.

Therefore, it is necessary to periodically stop the furnace so that an operator enters the furnace and cleans the upper air permeable plate 98 and / or the lower air permeable plate 100. However, the cleaning operation in the furnace is inefficient, and as a result, the productivity of the flameproof fiber is lowered.
JP 2001-288623 A (Claims)

  While the present inventor has made various studies in order to solve the above-described problems, the breathable plate can be taken out of the furnace and cleaned by forming the breathable plate in and out of the furnace by a slide mechanism. It has been found that the working efficiency is improved and the productivity of the flameproof fiber is improved.

  Further, by forming the breathable plate in two layers, the breathable plate in use can be replaced with a recycled breathable plate from which foreign matter has been removed or an unused breathable plate even during operation of the flameproofing furnace. It can be exchanged, and it has been found that the productivity of flame-resistant fibers is further improved.

  Furthermore, by making the breathable plate into a divided structure, the breathable plate can be taken out of the furnace even in a narrow space, and it has been learned that the productivity of flameproof fibers is improved from the space as well. It came to complete.

  Accordingly, an object of the present invention is to provide a flameproof heat treatment furnace that solves the above-mentioned problems.

  The present invention for achieving the above object is described below.

  [1] A heat treatment chamber in which hot air is sent in the vertical direction of the precursor fiber strand running horizontally in the furnace to make the strand flameproof, an upper flow path formed above the heat treatment chamber, and a lower portion formed below the heat treatment chamber A flameproof treatment furnace having a flow path and a hot air circulation path communicating the upper flow path and the lower flow path, between the heat treatment chamber and the upper flow path, and between the heat treatment chamber and the lower flow path A flameproofing treatment furnace in which a breathable plate insertion groove is formed in at least one of which, and a breathable plate is inserted along the breathable plate insertion groove so as to be freely inserted into and removed from the furnace.

  [2] A two-stage air-permeable plate insertion groove is formed in at least one of the space between the heat treatment chamber and the upper flow path and between the heat treatment chamber and the lower flow path, along the air-permeable plate insertion groove. The flameproofing treatment furnace as set forth in [1], wherein a breathable plate is inserted in and out of the furnace.

  [3] The air permeable plate is divided into a plurality of parts from the hot air circulation path side in the heat treatment chamber to the furnace wall side facing the hot air circulation path, and adjacent ones of these divided air permeability plates are detachable or bendable from each other. The flameproofing treatment furnace according to [1], which is connected to the flameproofing furnace.

  Since the flameproofing treatment furnace of the present invention is configured as described above, the breathable plate can be easily cleaned, and the productivity of flameproofing fibers can be improved in terms of work efficiency and space.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic front sectional view showing an example of the flameproofing furnace of the present invention.

  In FIG. 1, reference numeral 2 denotes a flameproofing treatment furnace, and a large number of strands 6 are formed in the heat treatment chamber 4 to form a strand group (pass) arranged in a horizontal plane (a plane perpendicular to the paper surface). . The strands 6 forming this path are folded back by a predetermined set of folding rollers (not shown) arranged outside the heat treatment chamber 4 and repeatedly supplied to the heat treatment chamber 4 to form a plurality of stages. Yes.

  Furnace walls 8a and 8b are provided on both sides of the strand 6 running in the heat treatment chamber 4 in the width direction so as to separate the inside from the outside. On the outside of one furnace wall 8 a, a hot air circulation path 14 that communicates the upper flow path (hot air discharge side flow path) 10 and the lower flow path (hot air suction side flow path) 12 of the heat treatment chamber 4, with the space portion 16 therebetween. Is provided.

  The space portion 16 may be omitted, but the space portion 16 may be used not only from the outside of the furnace wall 8b but also from the outside of the furnace wall 8a to adjust the temperature in the heat treatment chamber 4 by heating or cooling. It is more preferable.

  The heat treatment chamber 4 and the upper flow path 10 are partitioned by an upper air-permeable plate 18. The heat treatment chamber 4 and the lower flow path 12 are partitioned by a lower air-permeable plate 20. A plurality of air holes are formed in the upper air-permeable plate 18 and the lower air-permeable plate 20.

  Hot air heated by the heater 22 provided in the hot air circulation path 14 is sent into the heat treatment chamber 4 from the upper flow path 10 of the heat treatment chamber 4 by a blower 24 such as a fan, and travels by forming the path here. The existing strand 6 is flameproofed. Next, the hot air passes through the lower flow path 12 and enters the hot air circulation path 14 and is repeatedly heated by the heater 22 through the hot air circulation path 14.

  While the hot air circulation is repeated in the flameproofing treatment of the strand 6, foreign matter such as strands and powder derived from the strand accumulates in the hot air. This foreign matter accumulates in the air holes of the upper air permeable plate 18 and / or the lower air permeable plate 20. Therefore, the air permeable plate 18 and / or the lower air permeable plate 20 needs to be periodically rested, and the operator needs to enter the furnace and clean it.

  In this example, at least one of the upper air permeable plate 18 and the lower air permeable plate 20 is formed so as to be freely inserted into and removed from the furnace by a slide mechanism. Thereby, since an air permeable plate can be taken out and cleaned out of a furnace, cleaning work is easy.

  Here, the slide mechanism will be described by taking the upper air-permeable plate 18 as an example. A breathable plate insertion groove 26 is formed between the heat treatment chamber 4 and the upper flow path 10. The air permeable plate insertion groove 26 is provided with a guide rail (not shown), and the upper air permeable plate 18 is inserted along the guide rail so as to be freely inserted into and removed from the furnace.

  Similarly, when the sliding mechanism is used for the lower air-permeable plate 20, an air-permeable plate insertion groove 28 is similarly formed between the heat treatment chamber 4 and the lower flow path 12, and the inside and outside of the furnace are moved along the air-permeable plate insertion groove 28. The lower air-permeable plate 20 is inserted so that it can be inserted and removed.

  In addition, it is also possible to prepare a regenerative air-permeable plate from which foreign matter has been removed or an unused air-permeable plate, and replace this with the air-permeable plate after use. In this case, the idle time is shortened.

  FIG. 2 is a schematic front sectional view showing another example of the flameproofing furnace of the present invention. In the flameproofing treatment furnace 32 of this example, two stages of air-permeable plate insertion grooves 38a and at least one of between the heat treatment chamber 4 and the upper flow path 10 and between the heat treatment chamber 4 and the lower flow path 12 are provided. 38b or two-stage air-permeable plate insertion grooves 40a and 40b are formed, and the air is freely vented into and out of the furnace along the air-permeable plate insertion grooves 38a and 38b or the air-permeable plate insertion grooves 40a and 40b. Permeable plates 34a and 34b or lower air-permeable plates 36a and 36b are inserted.

  By adopting this two-tiered structure, the breathable plate in use can be replaced with a recycled breathable plate from which foreign matter has been removed or an unused breathable plate even during operation of the flameproofing furnace. The air flow rate in the circulation path can be kept stable.

  As for the replacement period of the air permeable plate, a 10% variation in the hot air speed at the outlet of the blower 24 is a target for the replacement. At this point, it is preferable to replace the breathable plate in use with a recycled breathable plate from which foreign matter has been removed or an unused breathable plate.

  Here, the replacement method of the air permeable plate will be specifically described by taking the upper air permeable plate as an example. Between the heat treatment chamber 4 and the upper flow path 10, two grooves for inserting the upper air permeable plate are provided. It has been.

  An upper air-permeable plate 34a is inserted into the upper groove 38a. The upper air-permeable plate 34b is inserted into the lower groove 38b. At this time, as the foreign matter accumulates in the upper air permeable plate 34a, the resistance differential pressure before and after the upper air permeable plate 34a gradually increases, and the amount of air in the hot air circulation path decreases momentarily. When the blower 24 is a fan, this reduced hot air circulation path air volume can be recovered to a stable operation state by increasing the rotational speed of the fan.

  The upper air permeable plate 34a is then removed. At this time, the pressure difference in the upper air permeable plate 34a is reduced to the pressure difference in the upper air permeable plate 34b, and the air volume in the hot air circulation path is increased for a moment. The increased amount of air in the hot air circulation path can be restored to a stable operation state by lowering the rotational speed of the fan of the blower 24.

  As with the upper air-permeable plate, the lower air-permeable plate is also used as a recycled air-permeable plate from which foreign matter has been removed or an unused air-permeable plate 36b even during operation of the flameproofing furnace. It can be exchanged, and the air volume in the hot air circulation path can be kept stable.

  Since the configuration other than the air permeable plate and the air permeable plate insertion groove is the same as in FIG. 1, the same reference numerals are assigned to the same portions, and the description thereof is omitted.

  FIG. 3 is a schematic front sectional view showing still another example of the flameproofing furnace of the present invention. In the flameproofing treatment furnace 42 of this example, the upper air permeable plate insertion groove 52 or the lower air flow is provided in at least one of the space between the heat treatment chamber 4 and the upper flow path 10 and between the heat treatment chamber 4 and the lower flow path 12. The upper air permeability plate or the lower air permeability plate is inserted along the upper air permeability plate insertion groove 52 or the lower air permeability plate insertion groove 54 so as to be inserted into and removed from the furnace.

  At least one of the upper breathable plate and the lower breathable plate is divided into three parts from the hot air circulation path side in the heat treatment chamber to the furnace wall side facing the hot air circulation path, and these adjacent breathable plates are adjacent to each other. They are connected to each other so as to be detachable or bendable.

  Here, a method for replacing the air permeable plate will be described by taking the upper air permeable plate as an example. The upper breathable plate is divided into three divided breathable plates 44a, 44b and 44c from the furnace wall 8a on the hot air circulation path 14 side in the heat treatment chamber 4 to the furnace wall 8b side on the side facing the hot air circulation path 14. The divided breathable plates 44a, 44b, and 44c are connected to the connecting portions 46a and 46b so as to be detachable or bendable.

  With this multi-divided structure, when taking out the breathable plate from the furnace, the divided breathable plates 44a, 44b and 44c can be removed or bent at the connecting portions 46a and 46b. Therefore, even when the external space of the furnace wall 8b is narrow, the divided air permeable plates 44a, 44b and 44c can be easily taken out of the furnace. Therefore, the exchange of the breathable plate is facilitated, and the productivity of the flameproof fiber can be improved in terms of work efficiency and space.

  As for the lower air-permeable plate, similarly to the upper air-permeable plate, the divided air-permeable plates 48a, 48b and 48c can be removed or bent at the connection portions 50a and 50b. Therefore, the divided breathable plates 48a, 48b and 48c can be easily taken out of the furnace, and the productivity of the flameproof fiber can be improved.

  Since the configuration other than the air permeable plate and the air permeable plate insertion groove is the same as in FIG. 1, the same reference numerals are assigned to the same portions, and the description thereof is omitted.

  Here, the detachable connection method and the foldable connection method in the connection portion will be described in more detail.

  FIG. 4 is a schematic view showing an example of a split breathable plate that is detachably connected. In the divided air permeable plates 62a, 62b and 62c divided into three, the divided air permeable plates 62a and 62b are respectively locked by L-shaped locking ridges 64a and 64b formed at the ends facing each other. It is meshed so that attachment or detachment is possible. Similarly, the split air permeable plates 62b and 62c are detachably meshed with each other by being locked by L-shaped locking ridges 64c and 64d.

  The detachable coupling method using the L-shaped locking ridge is suitable for increasing work efficiency because it is easy to detach.

  As another example of the detachable coupling method, there is a method of connecting the end portions of the divided air permeable plates facing each other with bolts. This detachable coupling method using bolts is suitable for increasing stability during operation because the connection is strong.

  FIG. 5 is a schematic view showing an example of a split breathable plate that is foldably connected. In the divided air permeable plates 72a, 72b and 72c divided into three, the divided air permeable plates 72a and 72b are connected to each other by hinges 74a attached to ends facing each other. Similarly, the split air-permeable plates 72b and 72c are connected to each other by a hinge 74b so as to be freely bent.

  In addition, in the example of FIGS. 3-5, although the division | segmentation of the air permeable plate was made into 3 divisions, it is not restricted to this, It can be set as arbitrary division numbers more than 3 divisions. Other modifications may be made as appropriate unless the gist of the present invention is changed.

It is a schematic front sectional view showing an example of the flameproofing treatment furnace of the present invention. It is a schematic front sectional drawing which shows the other example of this invention flameproofing processing furnace. It is a schematic front sectional drawing which shows the further another example of this invention flameproofing processing furnace. It is the schematic which shows an example of the division | segmentation air permeability plate connected so that attachment or detachment is possible. It is the schematic which shows an example of the division | segmentation air permeability plate connected so that bending is possible. It is a schematic front sectional view showing an example of a conventional flameproofing treatment furnace.

Explanation of symbols

2, 32, 42, 82 Flameproofing furnace 4, 84 Heat treatment chamber 6, 86 Strand 8a, 8b, 88a, 88b Furnace wall 10, 90 Upper flow path 12, 92 Lower flow path 14, 94 Hot air circulation path 16, 96 Space 18, 34a, 34b, 44a, 44b, 44c, 98 Upper air permeable plate 20, 36a, 36b, 48a, 48b, 48c, 100 Lower air permeable plate 22, 102 Heater 24, 104 Blower 26, 38a, 38b, 52 Upper air permeable plate insertion groove 28, 40a, 40b, 54 Lower air permeable plate insertion groove 46a, 46b Connection part of upper air permeable plate 50a, 50b Connection part of lower air permeable plate 62a, 62b, 62c, 72a, 72b, 72c Dividing breathable plates 64a, 64b, 64c, 64d L-shaped locking ridges 74a, 7 b hinge

Claims (3)

A heat treatment chamber in which hot air is sent in the vertical direction of the precursor fiber strand running horizontally in the furnace to make the strand flameproof, an upper flow path formed above the heat treatment chamber, and a lower flow path formed below the heat treatment chamber; A flameproofing furnace having a hot air circulation path communicating with the upper flow path and the lower flow path, at least of the space between the heat treatment chamber and the upper flow path and between the heat treatment chamber and the lower flow path. A flameproofing treatment furnace in which a breathable plate insertion groove is formed on one side, and a breathable plate is inserted in and out of the furnace along the breathable plate insertion groove. Two stages of air permeable plate insertion grooves are formed between at least one of the heat treatment chamber and the upper flow path and between the heat treatment chamber and the lower flow path, and enter and exit the furnace along the air permeable plate insertion groove. The flameproofing treatment furnace according to claim 1, wherein a breathable plate is inserted so as to be freely inserted and removed. The breathable plate is divided into a plurality of parts from the hot air circulation path side in the heat treatment chamber to the furnace wall side facing the hot air circulation path, and adjacent ones of these divided breathable plates are connected to each other so as to be detachable or bendable. The flameproofing furnace according to claim 1.

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