Composite seal structure, seal structure, and sealing method using the composite seal structure

Abstract

The fastening force is kept low while the flow of corrosive gases or radical gases to the elastomer member side is suppressed, and the permeation of gas from the elastomer member is reduced, thereby improving the sealing performance. [Solution] A composite seal structure 1 in which a constricted portion 3c of a ring-shaped elastomer member 3, which has a mating portion 3a, a constricted portion 3c and a protrusion portion 3b formed continuously therein, is fitted into a groove 2a that is continuous around the entire circumference on the outer or inner circumference side to prevent it from coming loose is sandwiched between a pair of flange portions 10, 11, and when not compressed and when compression begins, only the protrusion portion 3b is abutted against the pair of flange portions 10, 11, and when compressed at a predetermined compression rate or greater, the protrusion portion 3b and the curved arc-shaped cross-sectional portion of the deformed metal member 2 are brought into contact with the pair of flange portions 10, 11, sealing between the pair of flange portions 10, 11, and the metal member 2 suppresses the flow of corrosive gases or radical gases toward the elastomer member 3 while reducing gas permeation from the elastomer member 3.

Description

[Technical field]

[0001] The present invention relates to a composite seal structure, a seal structure, and a sealing method using the composite seal structure. [Background technology]

[0002] Conventionally, rubber O-rings are used in semiconductor manufacturing equipment or liquid crystal panel surface treatment equipment to create a nearly vacuum environment. However, in radical gas environments and corrosive environments, rubber O-rings are poor in corrosion resistance and radical resistance, so it is also known to use a seal material having an elastic seal body and a corrosion-resistant ring made of fluororesin (for example, Patent Document 1).

[0003] However, like the rubber material, the resin material covering the rubber material cannot avoid the permeation of gases such as the atmosphere from the high pressure side (atmospheric side) to the low pressure side (negative pressure side).

[0004] Therefore, for example, a low tightening force composite metal seal is known in which a rubber O-ring seal is integrated with the outer periphery of a metal seal shaped to be inserted into an O-ring seal groove, as shown in Patent Document 2. In this composite metal seal, the metal seal on the inner periphery prevents high-temperature corrosive gas from flowing into the rubber O-ring seal as much as possible.

[0005] Also known is a gasket having a metal layer or a plastic layer provided on the inner peripheral surface and / or outer peripheral surface of a ring-shaped rubber elastic body, as disclosed in Patent Document 3. In this gasket, the metal layer or the plastic layer is bonded to the ring-shaped rubber elastic body. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4625746 [Patent Document 2] JP 2023-156213 A [Patent Document 3] Japanese Patent Application Publication No. 11-201288 Summary of the Invention [Problem to be solved by the invention]

[0007] In the case of Patent Document 3, the grooves in the metal or plastic layer are shallow, so the metal or plastic layer must be bonded to the ring-shaped elastic body, and the labor required for the bonding process can be a problem. On the other hand, if the metal or plastic layer is not bonded, it is very likely to come off from the ring-shaped elastic body, making handling difficult.

[0008] Similarly, in the device of Patent Document 2, the metal seal and the rubber O-ring seal are not bonded together, and the metal layer or plastic layer is easily detached from the ring-shaped elastic body, making handling difficult.

[0009] The present invention has been made in consideration of these points, and its object is to improve sealing performance by reducing gas permeation from the elastomeric member while maintaining a low tightening force, and to make the member less likely to come off and easier to handle. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention is designed to prevent the metal member and the elastomer member from slipping out.

[0011] Specifically, in the first invention, An annular metal member having a continuous groove formed on an outer circumferential side or an inner circumferential side thereof, and an opening end of the groove being curved or bent so as to approach each other; a ring-shaped elastomer member having a fitting portion that fits into the recessed groove of the metal member and a protrusion portion that is continuous with the fitting portion via a narrowed portion having a thickness smaller than that of the fitting portion and against which a pair of flange portions abut, When not compressed and when compression starts, only the protrusions abut against the pair of flange portions, When compressed at a predetermined compression rate or more, the protrusions and the deformed metal member come into contact with each other to form a seal between the pair of flanges, The metal member Open End the minimum distance between the mutually facing portions is smaller than the maximum height of the fitting portion; The metal member is attached to the constricted portion. Open End are engaged to prevent dislodging.

[0012] According to the above-mentioned configuration, the elastomer member ensures sealing properties, and the metal member in contact with the pair of flanges in a compressed state prevents corrosive gas or radical gas from flowing toward the elastomer member, reducing the permeation of gas (atmosphere, etc.) from the elastomer member and improving sealing performance, and since the elastomer member ensures sealing properties from the start of compression, the clamping force of the metal member can be reduced. Open End The elastomer member is fitted into the constricted portion of the elastomer member to prevent it from coming loose, forming a composite seal. structure It is extremely easy to handle, for example when fitting the body into the seal groove.

[0013] In the second invention, in the first invention, In the compressed state, the curved arc-shaped cross-sectional portion of the metal member abuts against the pair of flange portions.

[0014] According to the above-mentioned configuration, since the curved portion comes into contact with the flange portion, the inner surface of the seal groove is less likely to be damaged than when the end of the metal member has a sharp cross section.

[0015] In a third aspect of the present invention, in the first aspect of the present invention, Open End The minimum distance between the opposing portions is 70% to 99% of the maximum height of the fitting portion.

[0016] Open End If the minimum distance between the opposing parts is less than 70% of the maximum height of the mating part, Open EndIf the resistance is greater than 99%, it becomes difficult to insert the connector between the connector and the connector. If the resistance is greater than 99%, the connector becomes easy to come out. Open End Since the elastomer member is easy to insert between the metal members and difficult to slip out once inserted, it does not slip out of the metal members and is easy to handle.

[0017] A seal structure of a fourth invention is a seal structure that exhibits sealing performance when the composite seal structure of the first to third inventions is fitted into a groove of a first member and fastened by a second member, The maximum height of the metal member is The depth of the groove is greater than the depth of the groove, and is smaller than the maximum height of the protrusion portion, The depth is greater than 100% and not greater than 130% of the depth of the groove.

[0018] According to the above-mentioned configuration, the maximum height of the metal member is appropriately large relative to the depth of the recessed groove, so that the protrusions are compressed first and then compressed together with the metal member at an appropriate compression ratio.

[0019] In the fifth aspect of the present invention, in the fourth aspect of the present invention, The maximum height of the protrusions is 105% or more and 145% or less of the depth of the grooves.

[0020] If the maximum height of the ridges is greater than 145% of the depth of the grooves, the compression rate of the ridges will be too high, and if it is less than 105%, the metal member will be compressed without the ridges being sufficiently compressed. However, with the above-described configuration, the depth of the grooves is set to an appropriate depth relative to the maximum height of the ridges, so that sealing performance is exhibited when the elastomer member and metal member are compressed at an appropriate compression rate.

[0021] In the sixth sealing method invention, a composite seal structure is prepared, the composite seal structure being formed by fitting a constricted portion of an annular elastomer member having a fitting portion, a constricted portion and a protrusion portion continuously formed in a constricted portion of an annular metal member having a constricted groove formed on an outer circumferential side or an inner circumferential side of the annular metal member so as to be retained in the constricted portion; The composite seal structure is sandwiched between a pair of flange portions, When uncompressed and when compression begins, the elastomer portion Material only the protrusions continuing to the fitting portion of the pair of flange portions via the constricted portion are brought into contact with the pair of flange portions, When compressed at a predetermined compression rate or higher, the protrusion portion and the curved, arc-shaped cross-sectional portion of the deformed metal member are brought into contact with a pair of flange portions, forming a seal between the pair of flange portions, and the metal member reduces gas permeation from the elastomer member while suppressing the flow of corrosive gas or radical gas toward the elastomer member.

[0022] According to the above-mentioned configuration, the narrowed portion of the elastomer member is fitted into the recessed groove of the metal member to prevent it from coming off, thereby forming a pair of flange portions. Sandwich Furthermore, while the elastomer member ensures sealing performance, the metal member that comes into contact with the pair of flange portions in a compressed state can reduce gas permeation from the elastomer member while suppressing the flow of corrosive gas or radical gas toward the elastomer member, and the elastomer member ensures sealing performance from the start of compression, so that the tightening force of the metal member can be reduced.

[0023] In a seventh aspect of the present invention, in the sixth aspect of the present invention, The metal member side is in a radical gas atmosphere.

[0024] According to the above-mentioned configuration, in the compressed state, the metal member is in contact with the pair of flange portions, and the flow of radical gas from the metal member into the elastomer member is suppressed, so that the durability of the elastomer member is significantly improved.

[0025] In an eighth aspect of the present invention, in the sixth or seventh aspect of the present invention, The maximum clamping force during compression is 3.44N / mm or more and 20.0N / mm or less.

[0026] According to the above-mentioned configuration, the elastomer member ensures sealing performance, so the maximum clamping force of the metal member can be kept lower than that of a metal seal. Meanwhile, the metal member, which is in compressed contact with the pair of flanges with an appropriate clamping force, can reduce gas permeation from the elastomer member while suppressing the flow of corrosive gas or radical gas to the elastomer member side. Effect of the Invention

[0027] As described above, according to the present invention, the elastomer member maintains sealing performance, and the metal member inhibits the flow of corrosive gas or radical gas toward the elastomer member while reducing gas permeation from the elastomer member. Therefore, while maintaining a low fastening force, the sealing performance is improved and the product is difficult to come loose and easy to handle. [Brief description of the drawings]

[0028] [Figure 1] FIG. 2C is an enlarged cross-sectional view of a portion I in FIG. 2B showing the composite seal structure according to the embodiment of the present invention. [Figure 2A] FIG. 2 is a plan view showing the composite seal structure. [Figure 2B] 2B is a cross-sectional view of the composite seal structure taken along line IIB-IIB in FIG. 2A. [Figure 2C] FIG. 2 is a perspective view showing a composite seal structure. [Figure 2D] FIG. 2 is an end view showing the seal structure before compression. [Diagram 3] 4A is a cross-sectional view showing a state in which an elastomer member and a metal member are in contact with a pair of flange portions, and FIG. 4B is a cross-sectional view showing a state in which the elastomer member and the metal member are compressed and deformed by the pair of flange portions, showing the results of a finite element method analysis. [Figure 4] 1 is a graph showing the relationship between compression rate and tightening force. [Diagram 5] 1 and shows a composite seal structure according to a first modified example. FIG. [Figure 6]1 and shows a composite seal structure according to a second modified example. FIG. [Figure 7] 1 and shows a composite seal structure according to a third modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0030] 1 and 2 show a composite seal structure 1 according to an embodiment of the present invention. The composite seal structure 1 includes an annular metal member 2 having a groove 2a formed on the entire circumference of the outer periphery, the open ends 2b of the groove 2a being curved so as to approach each other. The distance h4 between the pair of open ends 2b is smaller than the maximum height h5 of the inner periphery of the groove 2a (h4 <h5)。

[0031] In this embodiment, the cross section of the metal member 2 is a substantially semicircular shape that opens to the outer periphery, but may have various shapes with grooves, as in the modified example described later. The metal member 2 is made of stainless steel (SUS316L, SUS304, etc.), nickel alloy (C22, C276, 718, etc.), titanium, aluminum alloy, copper alloy, etc. It may be a molded product with a different thickness, or a press molded product with a constant plate thickness t. The plate thickness t is 0.15 mm or more and 0.60 mm or less, preferably 0.20 mm or more and 0.30 mm or less. The height h6 of the metal member 2 is 1.2 mm or more and 7 mm or less, preferably 1.8 mm or more and 3.8 mm or less. The maximum height h5 of the inner circumference of the groove 2a is h6-2×t(h4 <h5<h6)である。

[0032] The composite seal structure 1 further includes a fitting portion 3a that fits into the recessed groove 2a of the metal member 2, and an elastomer member 3 having a protrusion portion 3b that is continuous with the fitting portion 3a via a narrowed portion 3c that is thinner than the fitting portion 3a and that a pair of flange portions 10, 11 (shown only in FIG. 2D) abut against the fitting portion 3a as a first member and a second member. In this embodiment, the fitting portion 3a of the elastomer member 3 when not compressed is semicircular.

[0033] In this embodiment, the fitting portion 3a is formed on the outer peripheral side over the entire circumference. However, when the metal member 2 is provided on the inner peripheral side, the fitting portion 3a may be provided on the inner peripheral side.

[0034] The elastomer member 3 is made of silicone rubber, fluororubber, ethylene-propylene rubber, nitrile rubber, butyl rubber, acrylic rubber, SBR, chloroprene rubber, TPE (thermoplastic elastomer), or the like.

[0035] The inner diameter ID of the elastomer member 3 is 20 to 1270 mm, preferably 300 to 700 mm, and the maximum height h1 is 1.5 to 7.5 mm, preferably 2.5 to 4 mm. The compression rate Δh1 of the elastomer member 3 is based on 5% or more and 30% or less of h1. The groove depth D is 70% or more and 95% or less of the maximum height h1 of the elastomer member (0.70h1 ≤ D ≤ 0.95h1), preferably 75% or more and 85% or less (0.75h1 ≤ D ≤ 0.85h1). The radial width W of the cross section of the composite seal structure 1 is 2 to 12 mm, preferably 2.5 to 6 mm. For the first flange Department If the depth of the seal groove 12 formed in the 10 is D, the height h6 of the metal member 2 is equal to or greater than the depth D of the seal groove 12 and smaller than the maximum height h1 of the elastomer member 3 (D ≤ h6 < h1). The height h6 of the metal member 2 is preferably greater than 100% of the groove depth D and 120% or less (D < h6 ≤ 1.2D).

[0036] The height h2 of the constricted portion 3c of the elastomer member 3 is smaller than the maximum height h3 of the fitting portion 3a and also smaller than the distance h4 between the open ends 2b of the metal member 2 (h2 < h4 < h3). It is desirable to ensure an appropriate gap between the open ends 2b and the constricted portion 3c so that an excessive force is not applied to the elastomer member 3 during compression (0.75h4 ≤ h2 ≤ 0.9h4). The distance h4 between the open ends 2b is preferably 90% or more and 99% or less of the maximum height h1 of the elastomer member 3 (0.9h3 ≤ h4 ≤ 0.99h3).

[0037] As will be described in detail later, the height h6 of the metal member 2 when uncompressed is set to be lower than the height h1 of the elastomer member 3 so that only the protruding portion 3b abuts against the pair of flange portions 10, 11 when the composite seal structure 1 is uncompressed and when compression begins (h6

[0038] Although details will be described later, when the metal member 2 is compressed at a predetermined compression rate or more, the protrusion 3b and the deformed metal member 2 come into contact with each other, thereby forming a seal between the pair of flanges 10, 11.

[0039] In this embodiment, the fitting portion 3a when not compressed has a semicircular cross section, but may have a different cross-sectional shape as in the modified example described later.

[0040] -Finite element method analysis- The relationship between the compression ratio and the tightening force of the composite seal structure 1 was analyzed using commercially available finite element analysis software.

[0041] Based on the premise of static analysis and nonlinear structural analysis (contact, large deformation), the analysis was performed using the symmetry of the composite seal structure 1 as a 1 / 2 axisymmetric model as shown in Figure 3.

[0042] The pair of flanges 10, 11 were treated as rigid bodies, assuming that the amount of deformation of the pair of flanges 10, 11 was sufficiently small relative to the amount of deformation of the composite seal structure 1, and that the rigidity of the flanges 10, 11 was sufficiently high. The large deformation effect was taken into account when performing the analysis based on the amount of deformation and contact with friction. The compression ratio was calculated based on the height of the composite seal structure 1 when uncompressed, i.e., the height h1 of the elastomer member when uncompressed.

[0043] ​In this analysis, the elastomer member 3 used the physical property values ​​of silicone rubber with a hardness of 70, and the metal member 2 used the physical property values ​​of SUS316L.

[0044] As described above, the height h2 of the metal member 2 in the uncompressed state is set lower than the height h1 of the elastomer member 3 (h2

[0045] In other words, initially only the upper and lower elastomer members 3 were in contact with the pair of flange portions 10, 11, but at around the compression rate of 13%, the outer periphery of the metal member 2 also came into contact with the pair of flange portions 10, 11.

[0046] The tightening force increases linearly when the compression ratio reaches about 14%. It can be seen that after the compression ratio reaches 14%, both the metal member 2 and the elastomer member 3 are in stable contact with the pair of flange portions 10, 11, providing excellent sealing performance.

[0047] When the target fastening force was reached, the compression rate was approximately 22% and the maximum fastening force was 9.3 N / mm.

[0048] -Sealing method using composite seal structure- As shown in FIG. 2D as an example of a seal structure 13, the above-described composite seal structure 1 is attached to a first flange Department The seal is placed in the seal groove 12 of the flange 10 and sandwiched between the pair of flanges 10, 11. There is no particular limitation on the equipment in which it is used, but it is used, for example, in a portion of a pair of flanges 10, 11 that connects gas or liquid flow paths and seals between the inside and outside of the flow path in a semiconductor manufacturing device or a surface treatment device for liquid crystal panels.

[0049] ​When not compressed, only the upper and lower protrusions 3b of the elastomer member 3 are in contact with the pair of flanges 10, 11, respectively. In this embodiment, for example, the composite seal structure 1 is used such that the outer circumferential side (inside the flow passage) of the metal member 2 is in a radical gas atmosphere, and the inner circumferential side (outside the flow passage) of the elastomer member 3 is in an atmosphere of -80°C or higher and 250°C or lower. Since the protrusions 3b of the elastomer member 3 are in contact with the pair of flanges 10, 11 from the start of compression, sealing performance is reliably ensured.

[0050] Next, as the compression ratio is gradually increased, for example, as described above, at a compression ratio of around 13%, the metal member 2 also begins to abut against the pair of flange portions 10, 11, and when compressed at or above that compression ratio, the protrusion portion 3b and the deformed metal member 2 come into contact with the pair of flange portions 10, 11.

[0051] As a result, with an appropriate tightening force, the composite seal structure 1 seals between the pair of flange portions 10, 11, and the metal member 2 suppresses the flow of radical gas toward the elastomer member 3, while reducing gas permeation from the elastomer member 3.

[0052] It is desirable that the maximum tightening force during compression be kept between 3.44 N / mm and 20.0 N / mm. In other words, because the flexible elastomer member 3 ensures sealing performance, the maximum tightening force can be kept lower than that of a single metal seal.

[0053] In this way, while the elastomer member 3 ensures sealing properties, the metal member 2, which is in compressed contact with the pair of flange portions 10, 11, prevents radical gas from flowing toward the elastomer member 3, reducing gas permeation from the elastomer member 3. Furthermore, since the elastomer member 3 ensures sealing properties, the tightening force of the metal member 2 can be reduced.

[0054] In addition, during compression, the metal member 2 is in contact with the pair of flange portions 10, 11 with an appropriate tightening force, so that the flow of radical gas into the elastomer member 3 is effectively suppressed, and the durability of the elastomer member 3 is significantly improved.

[0055] In addition, in this embodiment, the outer peripheral side of the elastomer member 3 is in an atmosphere of -80°C or higher and 250°C or lower, but by appropriately changing the material of the elastomer member 3, seals with various physical properties (temperature range, sealing performance, etc.) can be achieved.

[0056] Furthermore, since the groove 2a of the metal member 2 encloses the fitting portion 3a of the elastomer member 3 all around, the fitting portion 3a is properly accommodated in the groove 2a of the metal member 2 so as not to come off when uncompressed or compressed.

[0057] Moreover, the cross-sectional shape of the metal member 2 Open End 2b are curved so that they approach each other, and the opposing Open End 2b engages with the constricted portion 3c of the elastomer member 3 to prevent it from coming off, forming a composite seal. structure Handling is extremely easy, for example when fitting the body 1 into the seal groove 12.

[0058] Therefore, according to the composite seal structure 1 of this embodiment, the elastomer member 3 maintains the sealing performance, and the metal member 2 reduces gas permeation from the elastomer member 3 while suppressing the flow of corrosive gas or radical gas toward the elastomer member 3, thereby improving the sealing performance while keeping the fastening force low, and making it difficult to come loose and easy to handle.

[0059] -Variation 1- Fig. 5 shows a composite seal structure 101 according to a first modified example of the embodiment of the present invention, which differs from the above-described embodiment in particular in the shape of the metal member 102. In the following modified examples, the same parts as those in Figs. 1 to 4 are given the same reference numerals and detailed description thereof will be omitted.

[0060] The metal member 102 of this modification example does not have a circular arc cross-section, but has a shape similar to the cross-section of a clay pot with a tapered opening side formed by pressing a metal plate. The inner diameter of the opening end 102b of the metal member 102 may be in a flat shape with a constant diameter, and the constricted portion 103c may also have a flat part. The protruding strip portion 103b has the same shape as in the above-described embodiment. The distance h4 between the opening ends 102b is narrower than the height h3 of the fitting portion 103a of the elastomer member 103 and slightly larger than the height h2 of the constricted portion 103c (h2 < h4 < h3). By configuring in this way, the same operational effects as in the above-described embodiment can be obtained.

[0061] -Modification Example 2- FIG. 6 shows a composite seal structure 201 according to Modification Example 2 of the embodiment of the present invention, which is different from the above-described embodiment particularly in that the shape of the metal member 202 is different.

[0062] The metal member 202 of this modification example has a substantially circular arc cross-section, but the opening end 202b side is bent so as to approach each other in the vertical direction. The distance h4 between the opening ends 202b is narrower than the height h3 of the fitting portion 203a and slightly larger than the height h2 of the constricted portion 203c (h2 < h4 < h3). By configuring in this way, the same operational effects as in the above-described embodiment can be obtained.

[0063] Note that the radially inner peripheral surface of the protruding strip portion 203b of the elastomer member 203 has a rounded shape. Also, the constricted portion 203c of the elastomer member 203 has a narrow shape without flat surfaces in the vertical direction according to the shape of the opening end 202b. However, there is no difference in terms of operational effects from the above-described embodiment.

[0064] -Modification Example 3- FIG. 7 shows a composite seal structure 301 according to Modification Example 3 of the embodiment of the present invention, which is different from the above-described embodiment particularly in that the shape of the elastomer member 303 is different.

[0065] The metal member 302 of this modification example has a circular arc cross-section as in the above-described embodiment, but the elastomer member 30 3It has a cross-sectional U-shape with a depression on the radially outer side. In this case, there is a relatively large gap between it and the inner surface of the metal member 302. The distance h4 between the open ends 302b is narrower than the height h3 of the fitting portion 303a and slightly larger than the height h2 of the constricted portion 303c (h2 < h4 < h3). By configuring it in this way, the same operational effects as those of the above-described embodiment can be obtained.

[0066] (Other Embodiments) The present invention may be configured as follows with respect to the above-described embodiment.

[0067] That is, in the above-described embodiment, the metal member 2 is provided on the outer peripheral side, but when the inner peripheral side is in an environment such as a radical gas, it is provided on the inner peripheral side. In this case, the elastomer member is fitted into the concave groove on the outer peripheral side from the outer peripheral side.

[0068] Further, in the above-described embodiment, the first member and the second member are a pair of flange portions 10 and 11, but it is not limited to the flange shape, and it may be configured by a pair of members in which a seal groove is formed in either one of them.

[0069] Note that the above embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

Explanation of Reference Numerals

[0070] 1 Composite seal structure 2 Metal member 2a Concave groove 2b Open end 3 Elastomer member 3a Fitting portion 3b Ridge portion 3c Constricted portion 10, 11 A pair of flange portions (first member and second member) 12 Seal groove 13 Seal structure 101 Composite seal structure 102 Metal member 102b Open end 103a Fitting portion 103c Waist 201 Composite seal structure 202 Metallic parts 202b Open end 202b Open end 203 Elastomer material 203a Fitting part 203b Projection 203c Waist 301 Composite seal structure 302 Metallic parts 302b open end 303 Elastomer parts 303a Fitting part 303c Waist

Claims

1. An annular metal member having a continuous groove formed on the entire circumference of the outer circumferential side or the inner circumferential side, and the open ends of the groove are curved or bent so as to approach each other; a ring-shaped elastomer member having a fitting portion that fits into the recessed groove of the metal member and a protrusion portion that is continuous with the fitting portion via a narrowed portion that is thinner than the fitting portion and with which a pair of flange portions abut, When not compressed and when compression starts, only the protrusions abut against the pair of flange portions, When compressed at a predetermined compression rate or more, the protrusions and the deformed metal member come into contact with each other to form a seal between the pair of flanges, a minimum distance between the opposing open ends of the metal members when not compressed is smaller than a maximum height of the fitting portion; After the fitting portion is inserted into the opposing portions of the open end of the metal member, the open end of the metal member is engaged with the constricted portion to prevent it from coming off. A composite seal structure comprising:

2. In the compressed state, the curved portions on the opening end side of the metal member are configured to abut against the pair of flange portions. The composite seal structure of claim 1 .

3. The minimum distance between the opposing open ends is 70% to 99% of the maximum height of the fitting portion. The composite seal structure of claim 1 .

4. A seal structure that exhibits sealing performance when the composite seal structure according to any one of claims 1 to 3 is fitted into a groove of a first member and fastened by a second member, The maximum height of the metal member is The depth of the groove is greater than the depth of the groove, and is smaller than the maximum height of the protrusion portion, The depth of the groove is greater than 100% and less than or equal to 130%. A seal structure characterized by:

5. The maximum height of the protrusion is 105% or more and 145% or less of the depth of the groove. The seal structure according to claim 4 .

6. a composite seal structure is prepared by inserting an annular metal member having a groove formed on an entire circumference of an outer circumferential side or an inner circumferential side thereof, the fitting portion of an annular elastomer member having a fitting portion, a constricted portion and a protrusion portion formed continuously into the groove of the annular metal member at opposing portions of an opening end of the metal member, and fitting the constricted portion to prevent it from coming off; the composite seal structure is sandwiched between a pair of flange portions in a state where the elastomer member is on an opposite side to the metal member and exposed; When the elastomer member is not compressed and when compression is started, only the protrusions continuing to the fitting portion of the elastomer member via the constricted portion are brought into contact with the pair of flange portions; In a compressed state at or above a predetermined compression rate, the protrusions and the curved arc-shaped cross-sectional portion of the deformed metal member are brought into contact with a pair of flange portions, forming a seal between the pair of flange portions, and the metal member reduces gas permeation from the elastomer member while suppressing the flow of corrosive gas or radical gas into the elastomer member. A sealing method using a composite seal structure.

7. The metal member side is in a radical gas atmosphere. A sealing method using the composite seal structure according to claim 6.

8. The maximum clamping force during compression is 3.44 N / mm or more and 20.0 N / mm or less. A sealing method using the composite seal structure according to claim 6 or 7.

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