JP2001263562A - Non-metal-made expansion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-metal-made expansion joint and an expansion joint using this non-metal-made expansion joint having expansibility, heat resistance, and pressure resistance endurable against use under a severe condition. SOLUTION: In this non-metal-made expansion joint, having an air-tight layer in a fluid side and a reinforced layer in an outer side thereof, by setting modulus of longitudinal elasticity of the reinforced layer provided in the outer side of the air-tight layer to five times or more preferably ten times or more its modulus of longitudinal elasticity, the non-metal-made expansion joint excellent in durability with maximum stress remarkedly reducible applied to the air-tight layer can be presented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power plant, a steel mill,
The present invention relates to a non-metallic expansion joint that is attached for the purpose of absorbing thermal distortion, vibration, and the like of intake and exhaust ducts and piping equipment of a chemical plant, guiding a high-temperature fluid, and at the same time, sealing the same.

[0002]

2. Description of the Related Art An expansion joint is disposed between a first conduit and a second conduit for guiding a high-temperature fluid, and absorbs distortion and vibration caused by heat of, for example, an intake / exhaust duct, piping equipment, and the like, and removes the high-temperature fluid. It is used for the purpose of guiding and sealing at the same time, and is indispensable for various plants and equipment. Conventionally, metal expansion joints used for these purposes are mainly made of metal. However, since the metal expansion joint has a small amount of displacement absorption and it is difficult to absorb displacement in multiple directions, it cannot withstand use in a place where use conditions are severe. Therefore, instead of such a metal expansion joint, a cloth having a large displacement absorption amount, for example,
A flexible joint method using a glass cloth as an elastic material (bellows material) has been proposed (for example, Japanese Patent Application Laid-Open No. 9-229).
266), and has been put to practical use.

[0003]

However, in recent years,
Non-metallic laminated elastics used for exhaust ducts, etc. are subject to large loads due to increased internal fluid pressure and increased fluid temperature due to increased efficiency and higher performance of boiler equipment. Therefore, measures are desired. Accordingly, an object of the present invention is to propose a non-metallic expansion joint having high durability and high elasticity, heat resistance, and pressure resistance that can withstand use under severe conditions.

[0004]

Means for Solving the Problems The inventors of the present invention have made use of material constants such as the modulus of longitudinal elasticity and thickness of a material constituting a laminated elastic material as factors, and conducted a structural analysis using a finite element method to eagerly determine optimum conditions. As a result of the study, the longitudinal elastic modulus of the reinforcing layer (outer skin) of the nonmetallic laminated elastic material is set to be larger than that of the inner fluid-tight layer. That is, when the longitudinal elastic modulus of at least one layer of the reinforcing layer is 3000 MPa or more and / or 5 times or more, preferably 10 times or more of the fluid-tight layer, the maximum stress applied to the hermetic (seal) layer is significantly reduced. It was found that the present invention was completed. That is, the present invention provides a connecting member for connecting a high-temperature fluid between a first tubular conduit and a second conduit for connecting the two conduits, and a fluid leaking to the fluid side to the outside. Airtight layer, not to
A joint made of a tubular non-metallic laminated elastic material having a reinforcing layer for supplementing the strength of the airtight layer laminated on the outside thereof, wherein at least one of the reinforcing layers of the reinforcing layer of the non-metallic laminated elastic material is provided. It is intended to provide a nonmetallic expansion joint having a longitudinal elastic modulus of at least 5 times, preferably at least 10 times the longitudinal elastic coefficient of the airtight layer.

According to the present invention, the airtight layer is preferably made of a polytetrafluoroethylene thin film or at least one elastomer material selected from FKM (fluoro rubber), IIR (butyl rubber), CR (chloroprene rubber), silicon rubber and the like. It is intended to provide the above-mentioned nonmetallic expansion joint, which is made of a seed. Further, in the present invention, the reinforcing layer is a woven fabric made of at least one selected from polyparaphenylene benzobisoxazole fibers, polyparaphenylene benzobisthiazole fibers, and aramid fibers. An expansion joint is provided.

Further, the present invention provides that the reinforcing layer is a mixed fiber woven fabric of glass fibers and at least one selected from polyparaphenylene benzobisoxazole fibers, polyparaphenylene benzobisthiazole fibers, and aramid fibers. A non-metallic expansion joint as described above is provided. The present invention also provides the above non-metallic expansion joint, wherein the reinforcing layer is integrally formed by impregnating and forming an airtight layer into the reinforcing layer.

Further, the present invention provides the above-mentioned non-metallic expansion joint, wherein the airtight layer and the reinforcing layer are integrally laminated via an adhesive layer. The present invention is characterized in that the adhesive layer is made of at least one selected from a rubber-based adhesive such as acrylonitrile rubber, silicone rubber, butyl rubber or a heat-fusible fluororesin material (agent). The present invention provides an expansion joint made of steel.

Further, the present invention provides the above non-metallic expansion joint, wherein a heat insulating layer made of at least one selected from ceramic felt and glass felt is arranged on the fluid side of the airtight layer. is there. By arranging the heat insulating layer inside the airtight layer, the influence of heat (fatigue) on the airtight layer and the reinforcing layer can be reduced.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. FIG. 1 is a sectional view of a nonmetallic expansion joint according to the present invention. When the expansion joint of FIG. 1 assumes a normal power plant, a cylindrical first conduit 15a corresponding to an exhaust port from a boiler and a cylindrical second conduit 15a corresponding to an exhaust port connected to a chimney are provided.
The first conduit 15a, which is connected to the conduit 15b via a non-metallic laminated elastic material, is a tubular duct, and is an integral structure, and is connected to one flange of the integral couplers 14a, 14d. Fastened by restraining tools (bolts and nuts) 11h and 11g. The other flange of the connecting tool and the holding plate 1
3a and 13d, one end of a cylindrical non-metallic laminated elastic member is clamped and fastened by restrainers (bolts and nuts) 11a and 11f, and the other end of the non-metallic laminated elastic member is held down by a holding plate 1.
The other connecting members 14b, 14 formed integrally with 3b, 13c
c is clamped and fastened between one flanges. Further, a second conduit 1 which is a cylindrical duct and the other flange of the coupling tool.
5b is fastened by restrainers (bolts and nuts) 11c and 11d. Further, on the fluid side, a baffle 18a, 1 of an integral structure attached for the purpose of changing the direction of the flow.
8b and restraints (stud bolts / nuts) 19a,
The heat of the internal fluid does not directly affect the laminated elastic members 12a, 12b by the heat insulating materials (glass felt) 16a, 16b fastened and fixed by 19b, 19c, 19d and the heat insulating materials (ceramic felt) 17a, 17b. It has a structure. However, the heat insulating material (glass felt) 16a, 1
6b and heat insulating material (ceramic felt) 17a, 17
b is used in combination of ceramic felt, glass felt, a combination of both, or lamination depending on the internal fluid temperature condition. The felt material is microscopically porous, and the pressure directly affects the laminated elastic members 12a and 12b. Effect.

As for the configuration of the cylindrical laminated elastic members 12a and 12b, a cross-sectional view in which the portion A in FIG.
It was shown to. FIG. 2 shows an airtight layer (polytetrafluoroethylene thin film 20) and an adhesive layer (heat-fusible fluororesin material (agent) 2).
1) and a reinforcing layer (non-metal woven fabric 22) are laminated in this order. As the adhesive, a rubber-based adhesive such as acrylonitrile rubber, silicon rubber, butyl rubber, or a heat-fusible fluororesin (agent) is considered, and the polytetrafluoroethylene thin film 20 and the non-metal woven fabric 22 are bonded. Is preferably a heat-fusible fluororesin material (agent) such as a tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA) film or a tetrafluoroethylene resin dispersion, and is used for bonding non-metal woven fabrics together. Is preferably a rubber-based adhesive.

As a laminate elastic material applied to a place where conditions are severe, a laminate having a three-layer structure of a polytetrafluoroethylene thin film 20, a heat-fusible fluororesin material (agent) 21 and a non-metal woven fabric 22 shown in FIG. 2 is used. The elastic material is used as an airtight layer for the internal fluid, and a backup material for the airtight layer is further provided outside the airtight layer. In this case, as shown in FIG.
b, or the above-mentioned expansion joint sheet material of FIG. 2 can be used in two layers. Also, as shown in FIG. 3, FKM (fluoro rubber), IIR (butyl rubber), CR
(Chloroprene rubber), silicone rubber, or another elastomer material 23a may be used as an airtight (seal) layer.
The longitudinal elastic modulus of the elastomer material is in the range of 1 to 5 MPa, which is much smaller than that of the polytetrafluoroethylene thin film of 398 MPa. Further, in FIG. 4, two layers of non-metallic woven fabrics 26 and 27 for reinforcement may be attached to the outside, so that the structure can withstand an external impact. In addition, as shown in FIG. 5, it is also possible to integrally form with the adhesive layers 25a, 25b, 25c.

Examples of the nonmetallic woven fabric used in the present invention include polyparaphenylene benzobisoxazole fiber, polyparaphenylene benzobisthiazole fiber,
A woven fabric made of aramid fiber is exemplified. The longitudinal elastic modulus in the present invention is also called Young's modulus, and is a value obtained by dividing stress at the time of material elongation deformation by strain. Since the measurement method is well known in the art, the description is omitted here. The nonmetal woven fabric used in the present invention has a basis weight of 50%.
２０００2000 g / m ² is preferable, and the number of weaves is preferably 15-60 pcs / 25 mm in length and 5-50 pcs / 25 mm in width. The thickness of the non-metal woven cloth 13 is, for example, 0.2 to
3.0 mm, preferably 0.3 to 2.0 mm. When the thickness is less than 0.2 mm, no reinforcing effect is obtained, and the thickness is 3.0 m.
If it exceeds m, the reinforcing effect becomes high but is not economical. The modulus of longitudinal elasticity of the material is a material constant, and is a value that does not change even if the thickness changes if the material is the same. However, since this value changes depending on the temperature of the material, the longitudinal elastic modulus in the present invention indicates a value at normal temperature.

The polytetrafluoroethylene thin film used in the present invention is not particularly limited, but it is desirable that the thin film should seal a fluid passing through the expansion joint and have good elasticity, heat resistance and chemical resistance. Softening point is 250 ° C
The above is good. The thickness of the polytetrafluoroethylene thin film is, for example, 0.1 to 1.0 mm, preferably 0.3 to 1.0 mm.
0.8 mm is preferable. If the thickness is less than 0.1 mm, the absolute strength is low, and it cannot withstand external force. Conversely, if it exceeds 1.0 mm, the flexibility is poor. The airtightness (sealability) required for this material refers to a material that does not allow the internal fluid to leak out. In other words, any pinhole can be detected by the pinhole tester.

The heat-fusible fluororesin material (agent) used in the present invention is not particularly limited as long as it can bond the nonmetallic woven fabric and the polytetrafluoroethylene thin film. A fluoroalkyl vinyl ether copolymer and a tetrafluoroethylene-hexafluoropropylene copolymer are preferred. In these copolymers, the content of fluorine is preferably 70 to 80% by weight. The thickness of the airtight layer, that is, the heat-fusible fluororesin material (agent) is, for example, 0.01 to 0.05 mm, and preferably 0.02 to 0.04 mm. The thickness is 0.
When the thickness is less than 01 mm, the heat-fusibility is poor, and unfused portions are formed.
On the other hand, if the thickness exceeds 0.05 mm, smoothness and uniformity of the sheet are impaired, for example, wrinkles are formed in the heat-sealed portion due to the flow.

The laminated elastic material of the present invention comprises an airtight layer and a reinforcing layer, and has a sealing property for preventing internal fluid from leaking to the outside.
It must have elasticity to follow the expansion and contraction of the duct due to heat, heat resistance to fluid temperature and flange temperature, chemical resistance not to be affected by internal fluid, and pressure resistance to pressure by internal fluid. is there. From such a viewpoint, the most suitable combination in the present invention is considered to be a polytetrafluoroethylene thin film for the airtight layer and a polyparaphenylenebenzobisoxazole fiber woven fabric for the reinforcing layer.

The laminated elastic material of the present invention comprises the above polytetrafluoroethylene thin film, a heat-fusible fluororesin material (agent),
And woven non-metallic fabric in this order, for example, 350-
It can be manufactured by pressing at a temperature of 380 ° C. for several minutes. Specific production methods include a batch press method, a belt press method, and a roll winding heat fusion method. In the batch press method, materials are prepared for each unit of use, stacked in the above order, and pressed while heating with a press machine to obtain a sheet material.

The belt press method is a method of heating a material while pressing the material between belts of a double belt machine to continuously obtain a sheet material. The double belt machine is provided with two endless belts provided in a direction facing each other across the material and capable of transporting the material in the same direction, a material introduction section, a heating section including a residual heat area, a cooling section. Are provided in order. The material moves while being pressed against the endless belt, is further heated and fused in the heating unit, cooled and fixed in the cooling unit, and then wound by a roll provided downstream of the double belt press. It is. Thus, according to the belt press method, the sheet material of the present invention can be manufactured continuously. The belt press method and the double belt press used for the same are known in the art, and are described in, for example, JP-A-10-180958.

In the roll winding heat fusing method, a material is tensioned to a certain degree, wound on a roll core material,
This roll core material is heated in a heating furnace to fuse the materials to obtain the sheet material of the present invention. According to the roll winding heat fusion method, the sheet material of the present invention can be manufactured continuously and in large quantities.

In order to process the sheet material obtained as described above into a cylindrical shape, only the portion of the connection portion (endless portion) of the sheet material which has been rolled into a cylindrical shape and the airtight layer and the reinforcing layer wrapped are peeled off. A processing method in which materials are alternately bonded together again with a heat-fusible fluororesin material (agent) or a rubber-based adhesive is used, which is generally called endless processing.

As the airtight layer, an elastomer material such as FKM (fluoro rubber), IIR (butyl rubber), CR (chloroprene rubber), silicon rubber, etc. can be selected in addition to the polytetrafluoroethylene thin film. Such an elastomeric material exhibits good sealing properties by immersing a liquid elastomeric material in a woven fabric or bonding an elastomer thin film to the woven fabric, and also has chemical resistance and elasticity. Is a material that can be replaced with a polytetrafluoroethylene thin film. However, since the heat resistance is inferior to the polytetrafluoroethylene thin film, it is necessary to limit the operating temperature range. Heat resistance temperature of polytetrafluoroethylene thin film is 260 ℃, FKM is 230 ℃, IIR
150 ° C, CR 130 ° C, silicon rubber 200 ° C
It is. Also, a polytetrafluoroethylene thin film with excellent chemical resistance can be used under most fluid conditions,
It is necessary to use an elastomer material properly depending on the type of fluid. As the elastomer material closest to the polytetrafluoroethylene thin film, an FKM (fluoro rubber) material can be mentioned.

The expansion joint of the present invention thus obtained is excellent in elasticity, heat resistance and pressure resistance.
The method of using the expansion joint of the present invention is the same as that of the conventional expansion joint, and does not require any special means or treatment.

[0022]

EXAMPLES Examples and comparative examples of the present invention will be described below. In Example 1, as shown in FIG. 2, the reinforcing layer had a thickness of 0.66 mm and a basis weight of 440 g /
m ² , weaving number 57 lines / 25mm, 46 lines / 2
Aramid fiber-glass fiber mixed woven fabric of 5 mm and elastic modulus of 3991 MPa and a polytetrafluoroethylene (PTFE) thin film of 0.3 mm thick and 398 MPa elastic modulus as an airtight layer, 0.02 mm in thickness A tetrafluoroethylene-fluoroalkylvinyl ether copolymer (PFA) film having an elastic modulus of 275 MPa was sandwiched and pressed at a pressing pressure of 0.2 MPa at a temperature of 370 ° C. for 10 minutes to obtain a 1.0 mm thick elastic sheet material. Also,
A part of the obtained sheet material was subjected to endless processing to obtain a laminated elastic material.

In Example 2, the reinforcing layer has a thickness of 0.1 mm.
3 mm, weight per unit area: 190 g / m ² , weaving number: 40 length / 25 mm, width 40 width / 25 mm, modulus of elasticity 1206
0.02 mm thick elastic modulus between 7 MPa polyparaphenylenebenzobisoxazole (PBO) fiber woven fabric and 398 MPa thin polytetrafluoroethylene (PTFE) thin film as an airtight layer A sheet material having a thickness of 0.6 mm was obtained by pressing a 275 MPa tetrafluoroethylene-fluoroalkylvinyl ether copolymer (PFA) film at a pressing pressure of 0.2 MPa and a temperature of 370 ° C. for 10 minutes. Further, the obtained sheet material was partly subjected to endless processing to obtain a laminated elastic material.

In Comparative Example 1, the thickness of the reinforcing layer was 0.1 mm.
A glass cloth having a longitudinal elastic modulus of 1849 MPa at 7 mm,
0.3mm thickness and longitudinal elastic modulus of 398MPa as airtight layer
A polytetrafluoroethylene (PTFE) thin film is sandwiched between a tetrafluoroethylene-fluoroalkylvinyl ether copolymer (PFA) film having a thickness of 0.02 mm and a modulus of longitudinal elasticity of 275 MPa, and a pressing pressure of 0.2 MPa
a, pressure bonding at 350 ° C for 10 minutes, thickness 1.0mm
Sheet material was obtained. Further, the obtained sheet material was partly subjected to endless processing to obtain a laminated elastic material.

In Comparative Example 2, a reinforcing layer having a thickness of 1.
A glass cloth having a modulus of longitudinal elasticity of 1266 MPa at 5 mm,
0.3mm thickness and longitudinal elastic modulus of 398MPa as airtight layer
A polytetrafluoroethylene (PTFE) thin film is sandwiched between a tetrafluoroethylene-fluoroalkylvinyl ether copolymer (PFA) film having a thickness of 0.02 mm and a modulus of longitudinal elasticity of 275 MPa, and a pressing pressure of 0.2 MPa
a, Pressure bonding at 350 ° C. for 10 minutes, thickness 1.8 mm
Sheet material was obtained. Further, the obtained sheet material was partly subjected to endless processing to obtain a laminated elastic material.

Evaluation tests were performed on the expansion joints (bending resistance), heat resistance and pressure resistance of the expansion joints obtained in the above Examples and Comparative Examples. Flex resistance is 300mm length x 35
With a bellows structure of 0 mm width, the bend is repeated under the conditions of a stretch width of 100 mm and a stretch speed of 100 times / minute, and 5,000 times, 10,000 times,
Evaluation was made by observing the appearance after bending 50,000 times and 100,000 times. The heat resistance was evaluated by measuring the tensile strength in a chamber at a predetermined temperature. Pressure resistance is outer diameter 1000mm x
A sheet material having a length of 400 mm is arranged in the configuration of FIG. 1, one side of the duct is closed, and the other side is pressurized by an air pressure of 10 Pa by a compressor. At that time, a stress applied to an airtight layer of the expansion joint is measured by a strain gauge. The stress was measured. The results are shown in Table 1.

From the results shown in Table 1, the longitudinal elastic modulus of the reinforcing layer of Example 1 was 10 times that of the airtight layer at 3000 MPa or more, and that of Example 2 was 30 times at 12000 MPa or more.
In the comparative examples, the longitudinal elastic modulus of the reinforcing layer was 3000 MPa or less and the ratio was 5 times or less in both Comparative Examples 1 and 2.
As a result, the expansion joint of the present invention shows no abnormality even after bending 50,000 times, and is excellent in elasticity. However, the expansion joint of the comparative example has perforations and fluffing after bending 50,000 times. In 100,000 times of expansion and contraction, holes were generated. Therefore,
It can be seen that the elasticity was poor. In addition, it can be seen that the expansion joint of the present invention has a higher tensile strength at any temperature than the comparative example and has good heat resistance. Further, the sheet material of the present invention has a maximum stress reduced by about 40% as compared with the comparative example.
It showed good pressure resistance.

[0028]

An airtight layer is provided on the fluid side as shown in the present invention.
In a non-metallic expansion joint having a reinforcing layer on its outside,
The longitudinal elastic modulus of the reinforcing layer is at least 5 times the longitudinal elastic modulus of the airtight layer,
Preferably, the non-metallic expansion joint having a high durability can be reduced by a factor of 10 or more to reduce the maximum pressure applied to the hermetic layer, and to have a high durability, having elasticity, heat resistance and pressure resistance that can withstand use under severe conditions. Provided.

[0029]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a nonmetallic expansion joint according to the present invention.

FIG. 2 is a first sectional explanatory view of a laminated elastic member A (main part) of FIG. 1;

FIG. 3 is a second sectional explanatory view showing a modification of the laminated elastic member A (main part) in FIG. 1;

FIG. 4 is a third sectional explanatory view showing a modification of the laminated elastic member A (main part) of FIG. 1;

FIG. 5 is a fourth sectional explanatory view showing a modification of the laminated elastic member A (main part) in FIG. 1;

[Explanation of symbols]

Reference Signs List 1 expansion joint 2 laminated elastic material (airtight layer: PTFE, reinforcing layer: PBO fiber woven fabric) 3 laminated elastic material (airtight layer: elastomer, reinforcing layer: PB
4 laminated elastic material (with air layer) 5 laminated elastic material (without air layer) 11a, 11b, 11c, 11d, 11e, 11f, 1
1g, 11h Restrainers (bolts and nuts) 12a, 12b Laminated elastic members (bellows materials) 13a, 13b, 13c, 13d Pressing plates 14a, 14b, 14c, 14d Connecting tools (14a and 1
4d is integral, 14b and 14c are integral 15a 1st conduit (fluid inlet side duct) 15b 2nd conduit (fluid outlet side duct) 16a, 16b Heat insulation layer (heat insulation material: glass felt) 17a, 17b Heat insulation layer (heat insulation material) : Ceramic felt) 18a, 18b Baffle (18a and 18b are integrated) 19a, 19b, 19c, 19d Restraint (stud bolt, nut) 20 Airtight layer (polytetrafluoroethylene thin film) 21 Adhesive layer (heat-fusible fluororesin) Material (agent)) 22 Reinforcement layer (PBO fiber woven fabric) 23a, 23b Elastomer 24a, 24b, 24c Air layer 25a, 25b, 25c Adhesive layer 26 Glass fiber woven fabric layer 27 Reinforcement layer (SUS line-containing glass fiber woven fabric)

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichi Wakasugi 6-1 Kashiwara, Ishioka City, Ibaraki Pref., Japan Construction Materials Techno-Laboratory F-term (reference) 3H104 JA07 JA08 JB02 JC04 JC08 JD02 LB08 LB36 LC04 LC09 LC14 LC16 LD01 LD06 LG03 LG30 MA06 MA08

Claims (8)

[Claims] 1. A connecting member disposed between a cylindrical first conduit and a second conduit for guiding a high-temperature fluid, for connecting the two conduits, and a fluid leaking to the fluid side to the outside. An airtight layer for preventing, a joint made of a tubular nonmetallic laminated elastic material in which a reinforcing layer for supplementing the strength of the airtight layer is laminated outside the joint, the reinforcing layer of the nonmetallic laminated elastic material is A non-metallic expansion joint characterized in that at least one layer has a longitudinal elastic modulus of at least 5 times, preferably at least 10 times the longitudinal elastic coefficient of the airtight layer. 2. The airtight layer is substantially composed of a polytetrafluoroethylene thin film or at least one selected from elastomer materials such as FKM (fluoro rubber), IIR (butyl rubber), CR (chloroprene rubber), and silicone rubber. The non-metallic expansion joint according to claim 1, wherein: 3. A woven fabric comprising at least one selected from the group consisting of a polyparaphenylene benzobisoxazole fiber, a polyparaphenylene benzobisthiazole fiber, and an aramid fiber.
Non-metallic expansion joint according to 1. 4. The reinforcing layer is a woven fabric of a blend fiber of at least one selected from polyparaphenylene benzobisoxazole fiber, polyparaphenylene benzobisthiazole fiber, and aramid fiber and glass fiber. Item 1
Or the non-metallic expansion joint according to 2. 5. The non-metallic expansion joint according to claim 1, wherein the reinforcing layer is integrally formed by impregnating and forming an airtight layer on the reinforcing layer. 6. The airtight layer and the reinforcing layer are integrally laminated with an adhesive layer interposed therebetween.
Non-metallic expansion joint according to any one of the above. 7. The adhesive layer according to claim 6, wherein the adhesive layer is made of at least one selected from a rubber-based adhesive such as acrylonitrile rubber, silicone rubber, butyl rubber, or a heat-fusible fluororesin material. Non-metallic expansion joint according to 1. 8. The non-metallic material according to claim 1, wherein a heat insulating layer made of at least one selected from ceramic felt and glass felt is disposed on the fluid side of the airtight layer. Expansion joints.