JP5162351B2 - Sealing equipment for carbonization furnace for carbon fiber production - Google Patents

Description

  The present invention relates to a sealing device that suppresses inflow of outside air into a carbon fiber producing carbonization furnace (hereinafter abbreviated as carbonization furnace) and outflow of gas in the carbonization furnace.

The carbon fiber is usually obtained by flame-treating a carbon fiber precursor bundle such as acrylic fiber in a flame-resistant furnace in an oxidizing atmosphere of 200 to 300 ° C. to obtain a flame-resistant fiber bundle, and then the flame-resistant fiber bundle is Furthermore, it manufactures by carbonizing in the carbonization furnace of 1000 degreeC or more of inert gas atmosphere.
By the way, in the carbonization treatment, when the outside air flows into the carbonization furnace and becomes an oxidizing atmosphere, the performance and quality of the carbon fiber may be deteriorated. Therefore, in order to maintain an inert atmosphere in the carbonization furnace, a sealing device for suppressing the inflow of outside air into the carbonization furnace and the outflow of gas in the carbonization furnace usually into the fiber bundle lead-in / out hole of the carbonization furnace Is attached.
As the sealing device, for example, in Patent Document 1, five or more stages and less than ten stages of expansion chambers are provided along the traveling direction of the fiber bundle, and the expansion chamber outside the third stage expansion chamber is counted from the carbonization furnace side. In at least one of the above, a labyrinth-type sealing device is disclosed in which gas discharge means for discharging an inert gas in a direction orthogonal to the traveling direction of the fiber bundle is installed.
JP 2001-98428 A

However, in the sealing device described in Patent Document 1, the sealing performance is not always sufficient, and external air may flow into the carbonization furnace or the amount of gas outflow from the carbonization furnace may increase. . In particular, the exhaust gas pipe for transferring the exhaust gas in the carbonization furnace to the combustion tower is closed as the usage time becomes longer, but when the exhaust gas pipe is closed, the pressure inside the carbonization furnace rises, Gas became easier to flow out of the carbonization furnace through the sealing device.
The present invention has been made in view of the above circumstances, and has excellent sealing performance, and even when the pressure in the carbonization furnace is increased, the carbon fiber production carbonization furnace seal capable of suppressing the outflow of gas from the carbonization furnace. An object is to provide an apparatus.

The present invention has the following configuration.
[1] In a labyrinth type sealing device that is connected to a fiber bundle lead-in / out hole of a carbonization furnace for carbon fiber production and through which the fiber bundle is passed,
A carbonization furnace connection hole connected to the fiber bundle lead-in / out hole of the carbonization furnace and an open hole opened to the outside atmosphere are formed, and has a seal device body in which the fiber bundle travels,
Inside the sealing device body, an expansion chamber of 10 stages or more and less than 30 stages is provided along the traveling direction of the fiber bundle,
A gas discharge means for discharging an inert gas in a direction substantially orthogonal to the traveling direction of the fiber bundle is installed in at least one of the expansion chambers on the carbonization furnace connection hole side from the eighth expansion chamber from the open hole side. A carbon furnace sealing device for carbon fiber production, characterized in that
[2] The carbon expansion furnace seal for carbon fiber production according to [1], wherein the two expansion chambers are provided so as to face each other, and gas discharge means are respectively installed in the two expansion chambers. apparatus.

  The sealing device for a carbon fiber producing carbonization furnace of the present invention is excellent in sealing performance and can suppress the outflow of gas from the carbonizing furnace through the sealing device even when the pressure in the carbonizing furnace rises.

An embodiment of a carbon fiber producing carbonization furnace sealing device (hereinafter abbreviated as a sealing device) according to the present invention will be described.
FIG. 1 shows a sealing device of this embodiment. The sealing device 10 is a labyrinth type device that is connected to the fiber bundle lead-in / out hole 21 of the carbonization furnace 20 and through which the fiber bundle A is passed, and has a seal device body 11 in which the belt-like fiber bundle A travels.

The sealing device main body 11 in the present embodiment is a square columnar box, and a carbonization furnace connection hole 11b connected to the fiber bundle lead-in / out hole 21 of the carbonization furnace 20 is formed on one end surface 11a. An open hole 11d that is open to the outside air atmosphere 30 is formed in the end surface 11c.
The carbonization furnace connection hole 11b and the open hole 11d in the present embodiment are rectangular holes having a long side in the horizontal direction.

Inside the sealing device main body 11, 15 stages of expansion chambers 12, 12... Are provided along the direction in which the fiber bundle A travels.
Here, the expansion chamber is a space sandwiched between two partition plates. The expansion chamber 12 in the present embodiment is formed in a space sandwiched between two rectangular partition plates 13 a and 13 a that are vertically attached to the upper surface of the sealing device body 11, and on the lower surface of the sealing device body 11. It is a space sandwiched between two rectangular partition plates 13b, 13b attached vertically. That is, in the present embodiment, the expansion chambers 12 are provided at the upper and lower portions of the seal device main body 11 so that the upper expansion chamber 12 and the lower expansion chamber 12 face each other.
In addition, the space 14 sandwiched between one end surface 11a in which the carbonizing furnace connection hole 11b of the sealing device body 11 is formed and the partition plates 13a and 13b, and the other end surface 11c in which the opening hole 11d of the sealing device body 11 is formed. And the space 15 sandwiched between the partition plates 13a and 13b is not an expansion chamber. This is because the space 14 has substantially the same atmosphere as the inside of the carbonization furnace 20 and the space 15 has the same atmosphere as the outside air.

In the present embodiment example, the upper partition plate 13a and the lower partition plate 13b are attached to the seal device body 11 so that their tips are opposed to each other. In the present embodiment, the number of expansion chambers 12 is fifteen, so that 16 partition plates 13a and 13b are attached to the upper surface or the lower surface of the seal device main body 11, respectively.
By attaching the partition plates 13a and 13b so as to face each other, a rectangular opening portion 13c having a long side in the horizontal direction is formed. It is preferable that the space | interval of the partition plates 13a and 13b which oppose each other becomes so large that it is close to the carbonization furnace connection hole 11b. As the fiber bundle A bends due to its own weight as it becomes closer to the carbonization furnace 20, the fiber bundle A may come into contact with the lower partition plate 13b. However, the interval between the partition plates 13a and 13b is set to the carbonization furnace connection hole 11b. If it is larger, the contact with the lower partition plate 13b of the fiber bundle A can be easily prevented.

  Although the space | interval of the partition plates 13a and 13a adjacent to the running direction of the fiber bundle A or the partition plates 13b and 13b is suitably selected according to the magnitude | size of the carbonization furnace 20, it is 5-20 cm, for example. It is preferable. If the interval between the partition plates 13a and 13a or the partition plates 13b and 13b is 5 cm or more, the sealing performance can be further improved. If the interval is 20 cm or less, the entire sealing device 10 does not become too large, and the installation place is easy. It can be secured.

  Moreover, it is preferable that the partition plates 13a and 13b are detachably attached to the seal device body 11 because the inside of the seal device body 11 can be easily cleaned and is excellent in maintainability.

  As a material constituting the sealing device body 11 and the partition plates 13a and 13b, a material having excellent heat resistance is preferably used, and specifically, graphite is preferable. If graphite is used as the material constituting the sealing device main body 11 and the partition plates 13a and 13b, it is difficult to be thermally deformed and excellent in dimensional stability. Therefore, the traveling position of the fiber bundle A can be accurately controlled to control the sealing device main body 11 and Contact with the partition plates 13a and 13b can be prevented. Further, even if the fiber bundle A comes into contact with the sealing device main body 11 and the partition plates 13a and 13b, the damage of the fiber bundle A can be reduced because graphite has good self-lubricity. In addition, since the dimensional stability is excellent, the partition plates 13a and 13b can be detachably attached to the seal device main body 11 by fitting the seals, and fixing with bolts is not necessary, and the partition plates 13a and 13 The removal work of 13b becomes simple. Further, since graphite is lightweight, it is easy to remove the sealing device 10 from the carbonization furnace 20 when performing maintenance such as cleaning.

  As shown in FIG. 2, in the sealing device 10 according to the present embodiment, the upper and lower expansion chambers 12a and 12b (that is, the expansion chamber 12a closest to the carbonization furnace connection hole 11b) are counted from the open hole 11d side. , 12b), one gas discharge means 16 is installed. Thus, when the gas discharge means 16 is arrange | positioned 1 each in each expansion chamber 12a, 12b, sealing performance will become higher.

The gas discharge means 16 discharges an inert gas (for example, nitrogen gas, argon gas, etc.) in a direction orthogonal to the traveling direction of the fiber bundle A.
The gas discharge means 16 in the present embodiment is a metal tube in which a large number of discharge holes 16a are formed along the length direction. Further, the discharge hole 16a in the present embodiment is directed to the opposite side of the fiber bundle A, and the inert gas is discharged in a direction substantially orthogonal to the traveling direction of the fiber bundle A.

In this embodiment, a porous plate 17 having a large number of holes is horizontally provided in the expansion chamber 12 closest to the carbonization furnace connection hole 11b. The perforated plate 17 discharges the inert gas uniformly in the direction of the fiber bundle A.
The material of the porous plate 17 is preferably graphite because it is difficult to be thermally deformed.

The fiber bundle A passed through the sealing device 10 is a belt-like fiber bundle obtained by flame-treating 100% acrylonitrile acrylic fiber or acrylic copolymer fiber containing at least 90% acrylonitrile, or carbonized in a carbonization furnace 20. It is the processed strip-shaped fiber bundle.
The total fineness of the fiber bundle A is preferably 300 tex or more from the viewpoint of the strength and processing efficiency of the fiber bundle A.

  The carbonization furnace 20 to which the sealing device 10 is attached has a heat treatment chamber 22 in which heaters 23 are provided above and below, and the fiber bundle A after the flameproofing treatment is carbonized. An end portion of the heat treatment chamber 22 is a fiber bundle outlet / inlet 21. Therefore, the sealing device 10 is connected to the heat treatment chamber 22 of the carbonization furnace 20.

The sealing device 10 is used as follows.
That is, the sealing device 10 is attached to the carbonization furnace 20 so that the carbonization furnace connection hole 11b of the sealing device 10 is connected to the fiber bundle lead-in / out hole 21 of the carbonization furnace 20.
Next, the heat treatment chamber 22 of the carbonization furnace 20 is heated by the heater 23, and the fiber bundle A is introduced into the sealing device body 11 from the open hole 11 d of the sealing device 10 so that the width direction of the fiber bundle A is horizontal. The fiber bundle A introduced into the sealing device body 11 travels through the sealing device body 11 and is introduced into the heat treatment chamber 22 through the carbonization furnace connection hole 11b and the fiber bundle lead-in / out hole 21. The fiber bundle A introduced into the heat treatment chamber 22 is heated and carbonized.
At that time, in the sealing device 10, the inert gas is discharged from the gas discharge means 16 in a direction substantially orthogonal to the traveling direction of the fiber bundle A in the expansion chamber 12 closest to the carbonization furnace connection hole 11 b. The discharged inert gas collides with the inner wall 11e of the sealing device body 11, and then reverses and flows in the direction of the fiber bundle A along the partition plates 13a and 13b. Then, after passing through the perforated plate 17, it flows into the adjacent expansion chamber 12 and further flows into the adjacent expansion chamber 12. Such a process is sequentially repeated toward the outer expansion chamber 12, and finally, each of the expansion chambers 12 is filled with the inert gas and the inert gas flows out from the open hole 11 d. As a result, the heat treatment chamber 22 and the outside air atmosphere 30 of the carbonization furnace 20 are shut off to obtain sealing performance.
Further, the fiber bundle A processed in the heat treatment chamber 22 is introduced into the seal device main body 11 through the carbonization furnace connection hole 11 b and the fiber bundle lead-in / out hole 21. The fiber bundle A introduced into the sealing device main body 11 travels inside the sealing device main body 11, and is led out to the outside air atmosphere 30 from the open hole 11d.
At that time, as described above, the sealing device 10 discharges the inert gas from the gas discharge means 16 to fill each of the expansion chambers 12 with the inert gas, and causes the inert gas to flow out from the open holes 11d. , Get sealing performance.

In the usage method of the sealing device 10, it is preferable to heat the inert gas discharged from the gas discharge means 16. If the inert gas is heated, even if the inert gas flows into the carbonization furnace 20, temperature unevenness in the carbonization furnace 20 hardly occurs.
Moreover, in the discharge of the inert gas by the gas discharge means 16, it is preferable to make a wind speed into 0.01 m / second or more and 0.3 m / second or less. If the wind speed of the inert gas is 0.01 m / second or more, the sealing performance can be further improved. On the other hand, if the wind speed of the inert gas is set to 0.3 m / second or less, the running posture of the fiber bundle A can be prevented, and the fiber bundle A can be prevented from touching and damaging the edges of the partition plates 13a and 13b. . Furthermore, the amount of inert gas used can be suppressed, and the manufacturing cost can be reduced.
Further, when the pressure inside the carbonization furnace 20 increases, it is preferable to increase the wind speed of the inert gas in response to the pressure increase in order to suppress a decrease in sealing performance.

  In the sealing device 10 as described above, the discharge of the inert gas is performed in the expansion chamber 12 on the carbonization furnace connection hole 11b side from the expansion chamber 12 on the eighth stage counted from the open hole 11d side. After each of the expansion chambers 12 is sufficiently filled with an inert gas, it is discharged to the outside air. Therefore, since the space filled with the inert gas is sufficiently present between the heat treatment chamber 22 of the carbonization furnace 20 and the outside air atmosphere 30, the sealing performance is high. As a result, the inflow of outside air into the carbonization furnace 20 and the outflow of gas from the carbonization furnace 20 through the sealing device 10 can be sufficiently suppressed. In particular, even when the exhaust gas pipe connected to the carbonization furnace 20 is closed and the pressure inside the carbonization furnace 20 is increased, the outflow of gas from the carbonization furnace 20 through the seal device 10 can be suppressed.

The sealing device of the present invention is not limited to the above embodiment. For example, in the above embodiment, the gas discharge means 16 may be provided only in one of the upper and lower expansion chambers 12 and 12 facing each other. Further, the porous plate 17 may not be provided in the expansion chamber 12 in which the gas discharge means 16 is installed.
Further, the number of expansion chambers 12 inside the sealing device main body 11 may be in a range of 10 steps or more and less than 30 steps. If the number of expansion chambers 12 is less than 10 stages, sufficient sealing performance cannot be obtained. If the number of expansion chambers 12 is 30 stages or more, the sealing device 10 becomes large, and it is difficult to secure an installation location.
In the above embodiment, the gas discharge means 16 is installed only in the expansion chamber 12 closest to the carbonization furnace connection hole 11b. However, in the present invention, the expansion chamber 12 in the eighth stage counted from the open hole 11d side. It should just be installed in at least one of the expansion chambers 12 on the carbonization furnace connection hole 11b side. If the gas discharge means 16 is installed in at least one of the expansion chambers 12 on the carbonization furnace connection hole 11b side from the expansion chamber 12 on the eighth stage counted from the open hole 11d side, the sealing performance of the sealing device 10 is enhanced. be able to. However, since the inclination of the pressure change is increased and the sealing performance can be further improved, the gas discharge means 16 may be installed only in the expansion chamber 12 closest to the carbonization furnace connection hole 11b as in the above embodiment. preferable.
Further, the ends of the partition plates 13a and 13b may not face each other. In that case, the number of stages of the expansion chamber 12 is counted separately for the upper expansion chamber 12 and the lower expansion chamber 12.
Further, the sealing device main body 11 may not be a rectangular box, but may be, for example, a cylindrical box, or another polygonal (for example, triangular, pentagonal, etc.) box. It may be.

(Examples and Comparative Examples)
Hereinafter, the present invention will be described with specific examples and comparative examples.
In this example and comparative example, a fiber bundle obtained by making flame resistance of 100% acrylonitrile acrylic fiber having a total fineness of 1000 tex is used as the fiber bundle.
A horizontal carbonization furnace was used as the carbonization furnace, and the sealing device shown in FIGS. 1 and 2 for the graphite material was attached to the fiber bundle introduction hole and the lead-out hole.
Then, carbonization was performed under the same conditions shown below by using a sealing device in which the number of expansion chambers and the like were the conditions shown in Table 1 below.
Number of fiber bundles input into the carbonization furnace: 200
Treatment time in the carbonization furnace: 1.5 minutes Temperature in the carbonization furnace: 1000 ° C
Opening width of carbonization furnace and sealing device: 1.3m
Fiber bundle travel gap D of the sealing device: 13 mm
Opening height of carbonization furnace: 80mm

In Example 1, the expansion chamber has 15 stages, and an inert gas gas discharge means is installed on the 15th stage from the open hole side, and the inert gas is discharged at a discharge surface wind speed of 0.07 m / sec. The pressure in the carbonization furnace was 5 Pa. As a result, there was no inflow of outside air into the furnace and outflow of furnace gas from the carbonization furnace through the sealing device, and the sealing performance was good.
In Example 2, the expansion chamber, the number of installation stages of the gas discharge means, and the discharge surface wind speed of the inert gas were the same as in Example 1, but the pressure in the carbonization furnace was 8 Pa. As a result, there was no inflow of outside air into the furnace and outflow of furnace gas from the carbonization furnace through the sealing device, and the sealing performance was good.
On the other hand, in Comparative Example 1, the number of expansion chambers, the discharge surface wind speed of the inert gas, and the pressure in the carbonization furnace are the same as those in Example 1, but the inert gas in the third stage counted from the open hole side. A sealing device provided with gas discharge means was used. As a result, there was no inflow of outside air into the furnace, but there was outflow of in-furnace gas from the carbonization furnace through the sealing device, and the sealing performance was insufficient.
In Comparative Example 2, the discharge surface wind speed of the inert gas and the pressure in the carbonization furnace are the same as in Example 1, but the expansion chamber has seven stages and the inert gas gas in the third stage counting from the open hole side. Discharge means was installed. As a result, there was no inflow of outside air into the furnace, but there was outflow of in-furnace gas from the carbonization furnace through the sealing device, and the sealing performance was insufficient.

It is sectional drawing which shows one Embodiment of the sealing apparatus of this invention. It is an expanded sectional view which shows the expansion chamber nearest to the carbonization furnace connection hole in the sealing device shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Sealing device 11 Sealing device main body 11a One end surface 11b Carbonization furnace connection hole 11c The other end surface 11d Open hole 12, 12a, 12b Expansion chamber 13a, 13b Partition plate 13c Opening part 16 Gas discharge means 16a Discharge hole 17 Perforated plate 20 Carbonization Furnace 21 Fiber bundle lead-out hole 22 Heat treatment chamber 23 Heater 30 Outside air atmosphere A Fiber bundle

Claims (2)

In a labyrinth type sealing device that is connected to a fiber bundle lead-in / out hole of a carbonization furnace for carbon fiber production and through which the fiber bundle is passed,
A carbonization furnace connection hole connected to the fiber bundle lead-in / out hole of the carbonization furnace and an open hole opened to the outside atmosphere are formed, and has a seal device body in which the fiber bundle travels,
Inside the sealing device body, an expansion chamber of 10 stages or more and less than 30 stages is provided along the traveling direction of the fiber bundle,
A gas discharge means for discharging an inert gas in a direction substantially orthogonal to the traveling direction of the fiber bundle is installed in at least one of the expansion chambers on the carbonization furnace connection hole side from the eighth expansion chamber from the open hole side. A carbon furnace sealing device for carbon fiber production, characterized in that   The carbon expansion furnace sealing apparatus according to claim 1, wherein two expansion chambers are provided so as to face each other, and gas discharge means are respectively installed in the two expansion chambers.

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