Gasket and coke oven temperature increase method

Abstract

To provide a gasket capable of easily switching between shutoff and circulation of fluid while ensuring sealability between flange parts of pipes, and a method for increasing a temperature of a coke oven.SOLUTION: In a gasket 10, a plurality of pipe bodies 3 is installed between flange parts 3a of a pipe 2 formed by connecting the flange parts 3a provided on each pipe body 3. The gasket 10 comprises a seal part 11 that is sandwiched between the flange parts 3a and seals between the flange parts 3a, and a blockage part 12 that blocks a flow path of the pipe 2 when the gasket 10 is installed between the flange parts 3a. The blockage part 12 is provided with a fragile part 14 that can be broken by a force applied to the blockage part 12 after the gasket 10 is installed between the flange parts 3a.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gasket to be installed between flange portions of a pipe formed by connecting flange portions provided on a plurality of pipe bodies, and a method for raising the temperature of a coke oven. [Background technology]

[0002] Between the flanges of a pipe formed by connecting multiple pipe bodies with each other, gaskets are generally used to seal the gap between the flanges to prevent fluid from leaking out of the pipe and to prevent gas or liquid from entering the pipe from outside. It is also common to insert a closure plate between the flanges of the pipe to block the flow path and stop the flow of fluid.

[0003] For example, in a coke oven, a riser pipe provided to discharge coke gas and tar generated when carbonizing coal charged in the carbonization chamber is also a type of piping. Patent Document 1 discloses a method for repairing the walls of a coke oven, and discloses an example in which, when repairing the walls of a coke oven, a sealing plate is inserted between the flange portions of an uprising pipe connected to a carbonization chamber to close the flow of gases and the like inside the uprising pipe.

[0004] The closing work on the riser pipe as disclosed in Patent Document 1 is sometimes performed when constructing a new coke oven or during the brick drying and temperature rising start-up process after brick replacement and repair, and its main purpose is to block the inflow of gas from the coke chamber into the inside of the riser pipe. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-213321 Summary of the Invention [Problem to be solved by the invention]

[0006] When a closure plate is inserted between the flanges of a riser pipe during closure work, after the work or process that requires gas shutoff is completed, the closure plate must be removed to allow fluid such as gas to flow through the pipe. This closure plate removal process requires the steps of disassembling the flanges, removing the closure plate, inserting a gasket between the flanges for sealing, and then reconnecting the flanges.

[0007] This process is complex, and for example, when removing the closure plate immediately before starting up a new or renewed coke oven, in addition to safety issues, it can be difficult to open the flanges due to restrictions on access to large pieces of equipment located nearby (such as the dry main).Safety issues include the risk of burns from contact with the closure plate or riser pipe equipment, which become hot as the coke oven body heats up.

[0008] Furthermore, if the sealing performance between the flanges deteriorates, this can become a starting point for leakage of the gas generated (coke gas) and the carbonization by-products contained in the gas (e.g., tar) during furnace operation after the coke oven is started up, which could lead to ignition at the base of the riser pipe or deterioration of the surrounding environment due to chronic gas leakage. Therefore, the present invention has been made to solve these conventional problems, and its object is to provide a gasket and a method for heating a coke oven that can easily block and switch the flow of fluid while ensuring sealing between flange portions of piping. [Means for solving the problem]

[0009] (1) In order to solve the above problems, one aspect of the present invention provides a gasket that is installed between flange portions of a pipe that connects multiple pipe bodies with flange portions provided on each pipe body, and that includes a sealing portion that is sandwiched between the flange portions and seals the gap between the flange portions, and a closing portion that blocks a flow path of the pipe when the gasket is installed between the flange portions, and the closing portion is provided with a fragile portion that can be broken by a force applied to the closing portion after the gasket is installed between the flange portions. (2) In the gasket described in (1), the fragile portion is preferably configured by intermittently providing a plurality of through holes in a part of the closing portion across both surfaces of the closing portion. (3) Furthermore, in the gasket described in (1), it is preferable that the fragile portion is configured as a groove portion formed in a part of the closing portion, in which the thickness of the material constituting the closing portion is thinner than the thickness of the closing portion other than the fragile portion. (4) Furthermore, in the gasket described in any one of (1) to (3), it is preferable that the closing portion contains a heat-resistant material that does not soften or melt at the highest temperature to which the closing portion is exposed when blocking the flow path of the piping. (5) Furthermore, in the gasket described in (4), the heat-resistant material is preferably a plate made of an inorganic material. (6) Furthermore, in the gasket described in (5), it is preferable that the inorganic material plate has either a through hole or a groove portion or both of the fragile portions, and that a material having a lower strength than the inorganic material at the temperature at which the fragile portions break is bonded to one or both sides of the inorganic material plate. (7) In the gasket described in (5) or (6), at least a portion of the sealing portion is preferably formed by bonding a material capable of sealing fluids to both sides of the inorganic material plate. (8) Furthermore, a method for heating a coke oven according to another aspect of the present invention is characterized in that a gasket according to any one of (1) to (7) is installed between flange portions of an ascent pipe to block a flow path of the ascent pipe, the temperature of a carbonization chamber of the coke oven is increased, and after the temperature is increased but before coal is charged into the carbonization chamber, a weak portion of the gasket is broken to allow fluid to flow inside the ascent pipe. [Effects of the Invention]

[0010] The gasket and coke oven heating method of the present invention can provide a gasket and coke oven heating method that can easily block and allow fluid flow while ensuring sealing between flange portions of pipes. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an ascent pipe of a carbonization chamber of a coke oven in which a gasket according to one embodiment of the present invention is installed. [Figure 2] FIG. 1 is a plan view of a gasket according to an embodiment of the present invention. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] FIG. 4 is an enlarged view of a portion indicated by an arrow A in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the following embodiments in terms of the materials, shapes, structures, arrangements, etc. of the components. In addition, the drawings are schematic, and therefore it should be noted that the relationship between thickness and planar dimensions, ratios, etc. may differ from the actual relationship, and the drawings may also contain parts where the relationship and ratio of dimensions differ from each other.

[0013] FIG. 1 is a schematic diagram showing a riser pipe of a coke oven carbonization chamber in which a gasket according to one embodiment of the present invention is installed. The riser pipe 2 shown in FIG. 1 is provided at the top of the carbonization chamber 1 of the coke oven, and discharges the coke oven gas and tar generated when the coal charged in the carbonization chamber 1 is carbonized to the outside. The riser pipe 2 is formed by connecting a plurality of (four in this embodiment) pipe bodies 3 with flange portions 3a provided on each pipe body 3. Each pipe body 3 is formed in a cylindrical shape. The flange portions 3a protrude outward in an annular shape from the end of the cylindrical pipe body 3. The carbonization chamber 1 of the coke oven is a space isolated from the outside air except when coal is charged and coke is discharged, and is connected to a dry main 6 via the riser pipe 2 and a bend pipe 5.

[0014] A water seal valve 4 is provided at the upper end of the riser pipe 2, and is shut off from the outside air by this water seal valve 4. A water seal valve (not shown) is also provided at the connection between the bend pipe 5 and the dry main 6. Between the flange portions 3a of the riser pipe 2, a gasket 10 according to this embodiment (see FIGS. 2 to 4) is installed to prevent fluids such as gas and tar inside the riser pipe 2 from leaking to the outside and to prevent gases and liquid fluids from the outside of the riser pipe 2 from penetrating into the riser pipe 2.

[0015] The gasket 10 is sandwiched between the flange portions 3a of the riser pipe 2 and includes a sealing portion 11 that seals the gap between the flange portions 3a, and a closing portion 12 that closes the flow path of the riser pipe 2 when the gasket 10 is installed between the flange portions 3a. Here, the closing portion 12 closes the flow path of the riser pipe 2 when the gasket 10 is installed between the flange portions 3 a, thereby blocking the flow of fluid such as gas inside the riser pipe 2 .

[0016] As shown in Figures 2 and 3, the closing portion 12 is composed of a circular inorganic material plate 12a, i.e., an inorganic material plate, as a heat-resistant material that blocks the flow path of the riser pipe 2. Examples of inorganic material plates include metal plates and ceramic plates. However, the closing portion 12 does not necessarily have to be composed solely of an inorganic material plate, and may be configured to partially contain a heat-resistant material that does not soften or melt at the maximum temperature to which the closing portion 12 is exposed when blocking the flow path of the riser pipe 2. For example, the closing portion 12 may partially contain a heat-resistant plate or sheet-like material to inhibit the flow of fluids such as gas within the riser pipe 2.

[0017] The seal portion 11 is sandwiched between the flange portions 3a of the riser pipe 2 to seal the gap between the flange portions 3a. Specifically, the seal portion 11 is installed between the flange portions 3a of the riser pipe 2 to prevent fluids such as gas and tar inside the riser pipe 2 from leaking outward through the gap between the flange portions 3a and to prevent gases and liquids from entering the riser pipe 2 from outside. The seal portion 11 is composed of an inorganic material plate 11a, i.e., an inorganic material plate, extending outward integrally from the inorganic material plate 12a of the closing portion 12, and seal material portions 11b bonded to both sides of the inorganic material plate 11a. The seal material portion 11b is composed of a material that can seal gases and liquids between the flange portions 3a, i.e., a material that has low permeability to gases and liquids and is unlikely to form gaps where it contacts the flange portions 3a. Examples of materials for the seal material portion 11b include rubbers, resins, paper, cork, and graphite. Note that the sealing portion 11 may be configured not entirely but partially by the inorganic material plate 11a and the sealing material portion 11b bonded to both sides of the inorganic material plate 11a. Also, the sealing portion 11 may be configured only by the sealing material portion 11b without the inorganic material plate 11a. Furthermore, if the inorganic material plate 11a itself has a sealing function, the sealing portion 11 may be configured only by the inorganic material plate 11a.

[0018] 2 and 3, a plurality of bolt insertion holes 13 are formed in the seal portion 11 at equal intervals in the circumferential direction so as to penetrate vertically. The gasket 10 is installed and fixed between the flange portions 3a by sandwiching the seal portion 11 between the flange portions 3a and inserting a plurality of bolts (not shown) into the bolt insertion holes 13 and fastening them with nuts (not shown).

[0019] 2 to 4, the closing portion 12 is provided with a fragile portion 14 that can be broken by a force acting on the closing portion 12 after the gasket 10 is installed between the flange portions 3a. The fragile portion 14 is provided in the closing portion 12 for the purpose of making it easy to break through the closing portion 12 after it is no longer necessary to block the riser pipe 2 after the gasket 10 is installed between the flange portions 3a.

[0020] 2 to 4, the fragile portion 14 is configured by intermittently providing a plurality of through holes in a portion of the closing portion 12 (a portion adjacent to the seal portion 11) across both surfaces of the closing portion 12. Specifically, the fragile portion 14 is configured by intermittently forming a plurality of through holes in an annular shape in a portion of the closing portion 12 adjacent to the seal portion 11. The fragile portion 14 is not limited to the case where a plurality of through holes are intermittently provided, and may also be configured by a groove portion, not shown, in a portion of the closing portion 12, in which the thickness of the material constituting the closing portion 12 is thinner than the thickness of the closing portion 12 other than the fragile portion 14.

[0021] When a through hole is provided as the fragile portion 14 as in this embodiment, there is a possibility that a fluid such as gas may flow through the through hole. However, since it is often not necessary to completely block the flow of a fluid such as gas, there is often no problem in forming the fragile portion 14 as a through hole. Whether or not the fragile portion 14 is formed as a through hole is desirably determined appropriately depending on the need to block the flow of a fluid such as gas. On the other hand, if it is desired to prevent the flow of a fluid such as gas through the fragile portion 14, it is desirably formed as a groove portion in which the thickness of the material forming the closing portion 12 is thinner than the thickness of the closing portion 12 other than the fragile portion 14, as described above. Furthermore, if it is desired to prevent the flow of a fluid such as gas through the fragile portion 14, the through hole may be closed with a material, such as a resin, that has a lower strength than the closing portion 12.

[0022] By providing the closing portion 12 with the fragile portion 14 in this manner, when the closing portion 12 is pierced by an external force, the fragile portion 14 breaks, and the sealing portion 11, which has the sealing function between the flange portions 3a, remains as a general full-flange gasket as it was when it was installed. This makes it possible to prevent fluids such as gas and tar inside the riser pipe 2 from leaking to the outside, and to prevent gases and liquid fluids from outside the riser pipe 2 from entering the inside of the riser pipe 2.

[0023] In the riser pipe 2 of this embodiment, as shown in Fig. 1, there are three portions where the flange portions 3a are connected to each other. A gasket 10 needs to be installed in each of these three portions. For this reason, the gasket 10 with the closing portion 12 is installed between the flange portions 3a at the base (lowest portion) of the riser pipe 2, and gaskets 10 without the closing portion 12 are installed between the flange portions 3a in other portions.

[0024] Next, a method for increasing the temperature of a coke oven according to this embodiment will be described. Before heating the coke oven, the gaskets 10 are installed between the flange portions 3a of the riser pipe 2. At this time, the gaskets 10 equipped with the closing portions 12 are installed between the flange portions 3a at the base (lowest part) of the riser pipe 2, and the gaskets 10 without the closing portions 12 are installed between the flange portions 3a in other parts.

[0025] At this time, the seal portion 11 is sandwiched between the flange portions 3a, and a plurality of bolts (not shown) are inserted into the bolt insertion holes 13 and fastened with nuts (not shown). Immediately after the gasket 10 is installed between the flange portions 3 a of the riser pipe 2, the gasket 10 installed between the flange portions 3 a at the base of the riser pipe 2 is in a state where the flow of fluids such as gas inside the riser pipe 2 is blocked by the closing portion 12.

[0026] Then, after the gasket 10 is installed between the flange portions 3a of the riser pipe 2, the coke oven is heated. In a newly installed, updated, or repaired coke oven, the newly installed refractory material and furnace body equipment are dried and heated by the heating. At this time, the gasket 10 installed between the flange portions 3a at the base of the riser pipe 2 has the closing portion 12 that blocks the flow of fluids such as gas inside the riser pipe 2, so that fluids such as gas inside the riser pipe 2 do not flow inside the riser pipe 2 and leak to the outside.

[0027] Then, when the refractory materials and furnace equipment have been sufficiently dried and heated to a state where operation can begin, the cover of the water seal valve 4 is opened and a rod or other member is used to strike the closing portion 12 of the gasket 10 installed in the riser pipe 2 from above, causing the fragile portion 14 to break. This allows fluid such as gas to flow inside the riser pipe 2. Even if the fragile portion 14 of the gasket 10 is broken, the flange portions 3a are sealed by the seal portion 11 that exists between the flange portions 3a. This prevents leakage of fluid such as gas inside the riser pipe 2 to the outside and prevents gas or liquid fluid from the outside of the riser pipe 2 from entering the inside of the riser pipe 2.

[0028] Then, some of the broken pieces of the gasket 10 that have fallen into the carbonization chamber 1 can be collected by opening the furnace cover (not shown) of the carbonization chamber 1, and then coal can be charged into the carbonization chamber 1 of the coke oven to produce coke. It is also possible to charge coal into the carbonization chamber 1 without recovering the fragments of the gasket 10 before charging the coal into the carbonization chamber 1, and recover the fragments of the gasket 10 together with the produced coke.

[0029] As described above, the gasket 10 according to this embodiment includes a sealing portion 11 that is sandwiched between the flange portions 3a and seals the gap between the flange portions 3a, and a closing portion 12 that closes the flow path of the rising pipe 2 serving as piping when the gasket 10 is installed between the flange portions 3a. The closing portion 12 is provided with a fragile portion 14 that can be broken by a force applied to the closing portion 12 after the gasket 10 is installed between the flange portions 3a.

[0030] This makes it possible to provide a gasket 10 that can easily switch between blocking and allowing fluid flow while ensuring the sealing performance between the flange portions 3a of the rising pipe 2 serving as piping. Furthermore, according to the gasket 10 of this embodiment, the fragile portion 14 is configured by providing a plurality of through holes intermittently in part of the closure portion 12 across both surfaces of the closure portion 12 . This allows the weakened portion 14 to be formed by a simple process of intermittently providing a plurality of through holes in a part of the closing portion 12.

[0031] Furthermore, according to the gasket 10 of this embodiment, the fragile portion 14 is configured as a groove portion formed in a part of the closing portion 12, in which the thickness of the material constituting the closing portion 12 is thinner than the thickness of the closing portion 12 other than the fragile portion 14. This makes it possible to prevent the flow of fluids such as gas through the fragile portion 14 with a simple configuration.

[0032] Furthermore, according to the gasket of this embodiment, the closing portion 12 contains a heat-resistant material that does not soften or melt at the highest temperature to which the closing portion 12 is exposed when blocking the flow path of the riser pipe 2 as a piping. As a result, the closing part 12 does not soften or melt at the maximum temperature to which it is exposed when closing the flow path of the riser pipe 2 as a piping, and can therefore perform the function of closing the flow path of the riser pipe 2 as a piping even at such maximum temperature.

[0033] Furthermore, according to the gasket of this embodiment, the heat-resistant material is an inorganic material plate (inorganic material plate 12a), so the closing portion 12 can be constructed using an inorganic material plate that is easily available and can be processed. Furthermore, according to the gasket of this embodiment, at least a portion of the sealing portion 11 is constructed by joining a material capable of sealing gases and liquids (sealing material portion 11b) to both sides of an inorganic material plate (inorganic material plate 11a).

[0034] This allows the space between the flange portions 3a to be sealed by the seal portion 11 with a simple configuration. Furthermore, according to the method for heating a coke oven according to this embodiment, the gasket 10 is installed between the flange portions 3a of the riser pipe 2 to block the flow path of the riser pipe 2. Thereafter, the temperature of the coke chamber 1 of the coke oven is raised, and after the temperature is raised but before coal is charged into the coke chamber 1, the fragile portion 14 of the gasket 10 is ruptured to allow the fluid inside the riser pipe 2 to flow.

[0035] This makes it possible to raise the temperature of the coke oven using the gasket 10 that can easily cut off and allow the flow of fluid while ensuring the sealing between the flange portions 3a of the uprising pipe 2. Although the embodiment of the present invention has been described above, the present invention is not limited to this and various modifications and improvements can be made.

[0036] For example, the gasket 10 is installed between the flange portions 3 a of the riser pipe 2 , but it may also be installed between the flange portions of a pipe other than the riser pipe 2 . Furthermore, the gaskets 10 equipped with the closing portions 12 are installed between the flange portions 3a at the base (lowest portion) of the riser pipe 2, and gaskets 10 without the closing portions 12 are installed between the flange portions 3a at other portions. However, the present invention is not limited to this, and the gaskets 10 equipped with the closing portions 12 may be installed between the flange portions 3a at the middle or upper portions in the vertical direction of the riser pipe 2, or may be installed between the flange portions 3a at all three connecting portions.

[0037] Furthermore, in the closing portion 12 and the sealing portion 11, a material having a lower strength than the inorganic material at the temperature at which the fragile portion 14 breaks may be bonded to one or both surfaces of the inorganic material plate 12a and the inorganic material plate 11a, i.e., the inorganic material plate. In this case, it is preferable to form either a through hole or a groove portion, or both, as the fragile portion 14 in the inorganic material plate 11a. [Example]

[0038] In order to verify the effects of the present invention, the gasket 10 shown in Figures 2 to 4 was installed between the flange portions 3a at the base (lowest part) of the riser pipe 2 shown in Figure 1 when the riser pipe 2 was installed in the coking chamber 1. 2 to 4, the gasket 10 is sandwiched between the flange portions 3a of the riser pipe 2 and includes a sealing portion 11 that seals the gap between the flange portions 3a, and a closing portion 12 that closes the flow path of the riser pipe 2 when the gasket 10 is installed between the flange portions 3a. The closing portion 12 is provided with a fragile portion 14 that can be broken by a force acting on the closing portion 12 after the gasket 10 is installed between the flange portions 3a.

[0039] The closing portion 12 is made of a stainless steel plate serving as a circular inorganic material plate 12a having a thickness of 1.5 mm. The sealing portion 11 includes a stainless steel plate serving as an inorganic material plate 11a extending outward integrally from the stainless steel plate of the closing portion 12. Both sides of the stainless steel plate are covered with a 2 mm-thick sealing material serving as a sealing material portion 11b. In this embodiment, a material containing rubber and inorganic fibers (equivalent to Valqua #6502) was used as the sealing material. As shown in Figures 2 and 3, the sealing portion 11 has a plurality of bolt insertion holes 13 formed at equal intervals in the circumferential direction so as to penetrate vertically.

[0040] In the closing portion 12, a plurality of slits as through-holes penetrating the stainless steel plate of the closing portion 12 were provided intermittently in the form of broken lines to form a ring at positions 3 mm inward from the inner circumferential surface of the piping body 3 constituting the riser pipe 2. These slits constitute the fragile portions 14. Each slit had a width of 0.5 mm, a length of 30 mm in the circumferential direction of the piping body 3, and a spacing of 5 mm between adjacent slits. The width of each slit, the spacing between adjacent slits, or the thickness of the fragile portions 14 can be determined appropriately depending on the external force applied to the fragile portions 14. For example, the ratio of the length of each slit to the spacing between adjacent slits can be approximately 3:1 to 50:1.

[0041] This gasket 10 was used in the following manner in the temperature raising process during the construction of a coke oven. First, after constructing the coking chamber 1 shown in Fig. 1, when the riser pipe 2 was installed in the coking chamber 1, gaskets 10 were installed between the flange portions 3a at the base (lowest portion) of the riser pipe 2. As shown in Fig. 1, there are three portions in the riser pipe 2 where the flange portions 3a are connected to each other. Gaskets 10 need to be installed in each of these three portions, but gaskets 10 equipped with closing portions 12 were installed between the flange portions 3a at the base (lowest portion) of the riser pipe 2, and gaskets 10 without closing portions 12 were installed between the flange portions 3a in other portions.

[0042] At this time, the seal portion 11 was sandwiched between the flange portions 3a, and a plurality of bolts (not shown) were inserted into the bolt insertion holes 13 and fastened with nuts (not shown). Thereafter, hot air was circulated in the coking chamber 1, and further, gas was burned in combustion chambers (not shown) on both sides of the coking chamber 1 to heat the bricks in the coking chamber 1, thereby raising the temperature of the coke oven. At this time, the gasket 10 installed between the flange portions 3a at the base of the riser pipe 2 has the closing portion 12 that blocks the flow of fluid such as gas inside the riser pipe 2, so that the fluid such as gas inside the riser pipe 2 does not flow through the riser pipe 2 and leak to the outside.

[0043] Then, after the entire carbonization chamber 1 reached a predetermined temperature, the cover of the water seal valve 4 was opened and a member such as a rod was used to strike the closing portion 12 of the gasket 10 installed inside the riser pipe 2 from above, causing the fragile portion 14 to break and allowing the flow of fluids such as gas inside the riser pipe 2. Even if the fragile portion 14 of the gasket 10 is broken, the flange portions 3a are sealed by the seal portion 11 that exists between the flange portions 3a. This prevents fluids such as gas inside the riser pipe 2 from leaking to the outside, and prevents gases or liquids from outside the riser pipe 2 from entering the inside of the riser pipe 2.

[0044] Then, some of the broken pieces of the gasket 10 that had been broken and fallen into the coking chamber 1 were collected by opening the furnace cover (not shown) of the coking chamber 1. In this way, after allowing the flow of fluids such as gas inside the riser pipe 2, coal was charged into the coke chamber 1 to produce coke. [Explanation of symbols]

[0045] 1 carbonization chamber 2. Rising pipe (piping) 3 Piping body 3a Flange 4 Water seal valve 5 Bend Pipe 6. Dry Maine 10 Gasket 11 Seal part 11a Inorganic material board 11b Sealing material section 12 Closure 12a Inorganic material board 13 Bolt insertion hole 14 Weakened part

Claims

1. A gasket installed between flange portions of a pipe formed by connecting a plurality of pipe bodies and flange portions provided on each pipe body, a sealing portion that is sandwiched between the flange portions and seals the gap between the flange portions; and a closing portion that closes a flow path of the piping when the gasket is installed between the flange portions, the closing portion is provided with a weakened portion that can be broken by a force applied to the closing portion after the gasket is installed between the flange portions, A gasket characterized in that the fragile portion is configured by intermittently providing a plurality of through holes in a part of the closing portion across both surfaces of the closing portion.

2. 2. The gasket according to claim 1, wherein the closing portion contains a heat-resistant material that does not soften or melt at the highest temperature to which the closing portion is exposed when closing the flow path of the pipe.

3. 3. The gasket according to claim 2, wherein the heat-resistant material is a plate of an inorganic material.

4. 4. The gasket according to claim 3, wherein the inorganic material plate has either a through hole or a groove portion, or both, as the fragile portion, and a material having a lower strength than the inorganic material at a temperature at which the fragile portion breaks is bonded to one or both sides of the inorganic material plate.

5. 5. The gasket according to claim 3, wherein at least a part of the sealing portion is formed by bonding a material capable of sealing fluids to both sides of the inorganic material plate.

6. 10. A method for heating a coke oven, comprising: installing the gasket according to claim 1 between flange portions of an uprising pipe to block a flow path of the uprising pipe; heating a carbonization chamber of the coke oven; and, after the temperature has been raised and before coal is charged into the carbonization chamber, rupturing the brittle portion of the gasket to allow fluid to flow inside the uprising pipe.

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