JP2004052900A - Metal seal and its mounting and using method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal seal having large amount of restoration with low fastening force. <P>SOLUTION: The metal seal is an annular shape one as a whole which is interposed between a pair of flat surfaces parallel to each other. The metal seal has an intermediate base part 3, a first contact projecting part 11 and a second contact projecting part 12. The first contact projecting part 11 is projected near the inside diameter and the second projecting part is projected near the outside diameter. Elastic twisted deformation is produced around the intermediate base part 3 in a mounted and pressed state. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to metal seals.
[0002]
[Prior art]
Conventionally, various materials such as rubber and resin have been used as seals for fixing flanges for vacuum, external pressure and internal pressure. Particularly, under severe conditions such as high vacuum / high pressure (external / internal pressure), high / low temperature, and application to corrosive fluids, metal seals are often used.
[0003]
[Problems to be solved by the invention]
However, this metal seal has the following problems. That is, the conventional metal seal generally has a high tightening force, and therefore, the thickness of a flange or the like as a mating member (seal mounting member) must be increased, and the weight and volume (space) of the device are increased. And other problems occur. Further, At a metal seal 31 of the conventional example shown in FIG. 4, the local metal seal 31 interposed between the mutual pair of flat surfaces parallel to 32, 33 at pressure seal portion K _1, K ₂ Plastic deformation, damaging the flat surfaces 32 and 33 °, that is, the mating members 34 and 35 such as flanges, and causing a problem in reusing the mating members 34 and 35 such as flanges. Naturally, when dismantling such as maintenance and inspection, high maintenance cost and maintenance time were required.
[0004]
The reason that the conventional metal seal 31 as shown in FIG. 4 locally plastically deforms and damages the flat surfaces 32 and 33 at the press-contact seal portions K ₁ and K ₂ is because of the rigidity of the metal seal 31. Due to the height, it is hardly elastically deformed, and receives the tightening force (in the direction in which the flat surfaces 32, 32 approach each other) as it is.
[0005]
SUMMARY OF THE INVENTION An object of the present invention is to make it easy and inexpensive, to have a small tightening force (regardless of whether it is a metal seal), a large restoring force, and to use a flange or the like as a mating member (mounting member). An object of the present invention is to provide a metal seal that can be reduced in thickness and contribute to weight reduction and compactness of the device.
Still another object of the present invention is to use the seal member for a long period of time without damaging it even if the material of the attachment member (partner member) to which the seal is attached is a fragile material such as ceramics or a soft material such as aluminum. The present invention provides a metal seal capable of performing sealing and a method of using the same, and furthermore, even when the depth tolerance of the sealing groove is large, the sealing performance (sealing performance) is always stable without variation. It is an object of the present invention to provide a metal seal that can exhibit (sealability), has a wide set height range in which the seal can be used, and is easy to mount.
[0006]
[Means for Solving the Problems]
In view of the above, the present invention provides an intermediate metal base and a first contact convex portion abutting on one of the flat surfaces in a totally annular metal seal interposed between a pair of flat surfaces parallel to each other. A second contact projection abutting the other of the flat surfaces, wherein the first contact projection protrudes near the inner diameter of the intermediate base, and the second contact projection is closer to the outer diameter of the intermediate base. And a torsion elastic deformation that rotates about the intermediate base portion is generated by a pressing force received from the pair of flat surfaces in the mounted and compressed state.
[0007]
The intermediate base is substantially rectangular in cross section, and the first and second contact projections are substantially semicircular to substantially semielliptical in cross section.
Further, the intermediate base has a substantially rectangular cross section, and the gap between the end surface of the intermediate base, on which the first contact projection is protruded, and one flat surface is gradually increased toward the outer diameter in the uncompressed state. And a gap between the end face of the intermediate base, on which the second contact projection is projected, and the other flat face gradually increases toward the inner diameter side in the uncompressed state. Is formed.
In addition, the regulating inner peripheral surface portion, the outer peripheral surface of which is in contact with the second contact convex portion in the mounted and compressed state, is connected to the other flat surface, and the second contact convex portion has two portions in the cross section. It was constituted so that it might contact.
[0008]
The method of mounting and using the metal seal according to the present invention is such that a first contact convex portion closer to the inner diameter is protruded on one of both end surfaces in the axial direction of the entire annular metal seal, and a second contact protrusion closer to the outer diameter is provided on the other. A first contacting state corresponding to one flat surface between the metal seal and a pair of flat surfaces parallel to each other; This is a method of inverting and mounting after a predetermined use period to a second assembled state in which the convex portion corresponds to the one flat surface.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
FIG. 1 and FIG. 2A show one embodiment of a metal seal (metal seal) S according to the present invention, and are cross-sectional front views in a free state (unmounted state), and FIG. 3 or FIG. () Is an explanatory sectional view of a main part showing a use state {mounted and compressed state}.
The metal seal S is made of stainless steel, spring steel, or other metal, and is manufactured by machining such as cutting or grinding, or by plastic working.
[0010]
The metal seal S is interposed between a pair of flat surfaces 1 and 2 that are parallel to each other, and is entirely annular, such as a circle, an ellipse, an oval, and a substantially rectangle. Describing the cross-sectional shape, it is composed of a substantially rectangular (rectangular) intermediate base portion 3, and a substantially semicircular first contact convex portion 11 and second contact convex portion 12. The first contact projection 11 contacts one flat surface 1, and the second contact projection 12 contacts the other flat surface 2. In FIGS. 2A and 3, the outline of the cross-sectional shape of the intermediate base 3 is indicated by a two-dot chain line. In a non-compressed state, the end face (long side) of the intermediate base 3 is orthogonal to the axis L direction. Reference numerals 5 and 6 are parallel to the flat surfaces 1 and 2 of mating members (mounting members such as flanges) 7 and 8.
[0011]
In particular, the first contact projection 11 protrudes toward the inner diameter of the end face (long side) 5 of the intermediate base 3, and the second contact projection 12 is the outer diameter end of the end face (long side) 6 of the intermediate base 3. It is protruded closer.
In short, with respect to the intermediate base 3 having a rectangular cross-section, the first and second contact protrusions are shifted from each other in the radial direction on the inner diameter side and the outer diameter side in directions opposite to each other in the axial direction. 12 are protruding. Moreover, in the illustrated example, the short side 9 (forming the inner peripheral surface) of the intermediate base portion 3 having a rectangular cross section and the substantially semicircular first contact convex portion 11 are continuous (without steps). The short side 10 (forming the outer peripheral surface) of the intermediate base 3 having a rectangular cross section and the second contact convex portion 12 are continuous (without steps).
[0012]
Then, as shown in FIG. 3, when the flat surface 1 of the mating member 7 and the flat surface 2 of the mating member 8 come close to each other and come into the mounted compression state, the pressing force F received from the pair of flat surfaces 1 and 2 is obtained. by _1, F _2, mainly in the middle base 3, collapsed as shown in FIG. 3. FIG 2 (a) (rotated), resulting in torsional elastic deformation. This torsional elastic deformation is restored to the original state {free state posture} of FIG. 2A when the pair of flat surfaces 1 and 2 are separated.
[0013]
In the conventional metal seal 31 shown in FIG. 4, the approach of the pair of flat surfaces 32, 32 is tried to be received by the compression of the metal seal 31 which is almost still. After the micro-elastic deformation, the press seal portions K ₁ and K ₂ are locally plastically deformed and damaged, and at the same time, the mating members 34 and 35 are also damaged. On the other hand, in the metal seal S according to the present invention, the pressing forces F ₁ , F ₂ of the mating members 7, 8 (flat surfaces 1, 2) are skillfully rotated about the intermediate base 3.柔軟 By receiving flexibly by torsional elastic deformation, the first contact convex portion 11 comes into contact with one flat surface 1 of the pressure contact seal portion K ₁ , and the second contact convex portion 12 becomes the other flat surface 2. preventing pressure seal portion K ₂ of contact, to prevent the plastic deformation (or decreases), to prevent damage to the first and second contact protrusions 11, 12, and damage to the flat surfaces 1 and 2 it can.
[0014]
FIGS. 2B, 2C, and 2D are cross-sectional views illustrating various other embodiments. Compared to FIG. 2A, FIG. The radial dimension E of the intermediate base 3 is small, and the cross section of the intermediate base 3 is a rectangle (rectangle) approaching a square. In FIG. 2C, conversely, the radial dimension E of the intermediate base 3 is large, and the cross-sectional shape of the intermediate base 3 is set to be an elongated rectangle (flat rectangle). In FIG. 2 (D), the axial dimension {short side length} of the intermediate base 3 is set smaller than that of FIG. 2 (A) to form an elongated rectangle (flat rectangle). Things.
2B, 2A, and 2C, the torsional elastic deformation tends to occur gradually, and the tightening force can be reduced. FIG. 2D is easier to twist and elastically deform than FIG. 2A and has a smaller tightening force.
[0015]
Next, FIG. 5 is a diagram for explaining how to attach and use the metal seal S.
In FIG. 5A, damaged portions (damaged portions) J ₁ and J ₂ indicated by thick short lines may occur on the flat surfaces 1 and 2. That is, the damaged portion J ₁ of the inner diameter closer to the one flat surface 1 by the first convex contact portion 11 of the metal seal S is generated outside the other flat surface 2 by the second convex contact portions 12 of the metal seal S径寄Ri sometimes damaged portion J ₂ of occurs. The assembled state in which the first contact protrusion 11 corresponds to (abuts) one of the flat surfaces 1 is referred to as a first assembled state.
[0016]
In such a case, as shown in FIG. 5A to FIG. That is, the metal seal S is once disassembled and taken out, and the vertical direction in the figure is exchanged (vertically inverted), so that the second contact convex portion 12 is brought into the second assembled state corresponding to the one flat surface 1. As apparent from FIG. 5 (B), the original damaged portions J ₁ and J ₂ do not come into contact with the inverted second and first contact convex portions 12 and 11 but come into contact with a new surface, so that they are used. The period can be extended twice (the life of the mating members 7, 8 such as flanges can be doubled).
In the metal seal S of the present invention, the first contact protrusion 11 and the second contact protrusion 12 are used in a different position in the radial direction (distance from the axis L), and are assembled (mounted) by inversion. ) To extend the service life.
[0017]
Next, in FIG. 6, when the spacing dimension (seal height dimension) of the flat surfaces 1 and 2 is further reduced from the state of FIG. 3, the corners 14 and 15 surrounded by circles M and N are formed. The state of compression which contacted flat surfaces 1 and 2 is shown. At this time, the substantially triangular space portions 16 and 17 have a closed chamber shape (air pool). When the space portions 16 and 17 as such air reservoirs are formed, for example, when used as a vacuum seal, there is a problem that it takes time to reach a specified degree of vacuum, and an internal pressure seal or an external pressure seal is required. As a result, it takes a long time to reach a predetermined pressure. In addition, it takes time to replace (change) a sealed fluid of a different type. Alternatively, when a special fluid is used in the pipe, fluid or air remaining in the air reservoir (previous process) is mixed.
[0018]
Therefore, as shown by the dotted lines in FIG. 6, small notches 18 and 19 are formed in the corners 14 and 15 so that the fluid in the spaces 16 and 17 can escape outward. In addition, a small through hole may be formed in the intermediate base portion 3 to allow the fluid to escape outward similarly (not shown). Further, in order to prevent the corners 14 and 15 from contacting the flat surfaces 1 and 2 and damaging the flat surfaces 1 and 2, the corners 14 and 15 are rounded (have a rounded shape). ) Is also preferred.
[0019]
Next, in another embodiment shown in FIG. 7 and FIG. 13, the metal seal S is such that the intermediate base 3 has a substantially rectangular shape such as a parallelogram having a horizontal cross section, and the first contact convex portion 11 protrudes. The end surface 5 is formed on a slope surface (taper surface) in which the gap 20 between the end surface 5 of the intermediate base portion 3 and one flat surface 1 gradually increases toward the outer diameter side in the uncompressed state in FIG. ing. Further, the gap 21 between the other end surface 6 of the intermediate base 3 on which the second contact protrusion 12 is projected and the other flat surface 2 is gradually increased toward the inner diameter side in the uncompressed state of FIG. The other end surface 6 is formed on a surface (taper surface).
[0020]
As shown in FIGS. 14, 15, and 16, the spacing H between the pair of flat surfaces 1 and 2 is reduced from the uncompressed state to the inner peripheral surface side. There is an advantage that the corner 15 between the short side 9 and the end surface (long side) 6 is less likely to contact (contact) the other flat surface 2. In this way, the other flat surface 2 is prevented from being damaged (by the corners 15). In addition, the interval from FIG. 13 to FIG. 15 (or FIG. 16) {the change in the set height or the seal height ΔH can be increased, so that the restoring force as the metal seal S is large}. The elastic deformation region is wide. There are the following advantages. In other words, since the tolerance of the crushing allowance in the final use state becomes large, it is possible to use in a wide range of the set height H, and the dimensions of the recesses (concave grooves) of the mounting members 7 and 8 such as flanges. Sufficient sealing performance (sealing performance) can be achieved even if the tolerances vary. Alternatively, a stable sealing property (sealing property) can be exhibited by following a pressure (fluctuation) cycle, a temperature (fluctuation) cycle, or the like.
[0021]
Next, as in still another embodiment shown in FIG. 8, the inclined (tapered) end surfaces 5 and 6 of FIG. 7 are formed into a curved shape (see the solid line) or a concave shape. It is also preferable to form a curved shape (see a two-dot chain line). That is, the selection can be made in consideration of the shapes of the recesses and grooves of the mating members 7 and 8 and the degree of variation in the dimensional tolerance.
9 and 10 show another embodiment, in which the intermediate base 3 has a rectangular cross-sectional shape, and the first contact convex portion 11 and the second contact convex portion 12 have a small rectangular cross-sectional shape. Yes, the overall cross-sectional shape is an angular Z-shape. In the case of this metal seal S, in the mounted and compressed state, it undergoes torsional elastic deformation as shown in FIG. That is, the corner 23 of the small rectangular first contact protrusion 11 near the outer diameter and the corner 24 of the second contact protrusion 12 near the inner diameter press against the flat surfaces 1 and 2. In this way, sharp edges (corners 23 and 24) bite into the flat surfaces 1 and 2 and exhibit high sealing performance.
[0022]
FIG. 11 is a cross-sectional view showing still another embodiment, which differs from FIG. 2 in that the first contact protrusion 11 and the second contact protrusion 12 are substantially triangular. Has a similar configuration. The tops 25, 26 of the substantially triangular first and second contact portions 11, 12 can be freely formed into a small round shape, a flat shape, or a sharp edge shape. Although not shown, it is also preferable to arrange the intermediate base portion 3 of FIG. 9 or 11 in a gradient (tapered shape) as shown in FIGS. 7 and 8 (not shown).
As in another embodiment shown in FIG. 12, the intermediate base 3 itself is formed in a gradient (tapered shape), and the pair of corresponding tops 25A, 26A is used to form the first and second contact projections. 11 and 12 can also be configured. The tops 25A and 26A are free to have a flat tip, a small radius, or a sharp edge.
[0023]
By the way, the unique configuration shown in FIGS. 13 to 16 is such that a regulating inner peripheral surface portion 27 is continuously provided on the other flat surface 2 to form a concave portion (a concave groove) in the mounting member 8, and FIG. In the mounted compressed state shown in FIGS. 14 to 16, the outer peripheral surface of the second contact convex portion 12 abuts on the regulated inner peripheral surface portion 27 in the mounted compressed state shown in FIGS. The second contact protrusion 12 is configured to contact at two points {two points} of the flat surface 2 and the regulation inner peripheral surface 27.
[0024]
More specifically, as the metal seal S, in addition to the above-described two places (two points), the first contact convex part 11 is in contact with one flat surface 1 at one place (one point). Then, it can be said that there are three places (three points) of contact. As described above, since the second contact protrusions 12 are configured to be contacted at two places (two points), the metal seal S is overly collapsed by the pressing of the pair of flat surfaces 1 and 2 approaching each other ( It is possible to prevent over-torsion. In addition, it is possible to prevent the device from falling down too much and effectively generate a repulsive force due to torsion. Desirably, the state shown in FIG. The generation of the space portions 16 and 17) can be prevented. Further, the two-point contact of the second contact protrusion 12 disperses the pressing force applied to the mating member 12, and has an effect of preventing the flat surface 2 from being damaged.
[0025]
When the metal seal S according to the present invention is used in a semiconductor manufacturing apparatus or the like, one of the mating members (mounting members) 7 and 8 may be made of stainless steel and the other may be made of a soft metal such as aluminum. In such a case, the two-point contact side (the side with which the second contact convex portion 12 contacts) may be set to a soft metal side such as aluminum to suppress the damage.
[0026]
By the way, in FIG. 13, a small seal having a height dimension (corresponding to H in FIG. 13) of the metal seal S in a free state of 1.4 mm and an outer diameter D of 7.3 mm is made of stainless steel. The test piece was manufactured by using {SUS316L double melt} and tested for elasticity and restorability. FIGS. 13 to 16 show the state of elastic deformation of the metal seal S by FEM (Finite Element Method) analysis, and show the analysis values for the contact surface pressure P at each of the above three-point contact positions. Also shown in the graph.
[0027]
In FIG. 13, the spacing dimension (set height or seal height) H between the flat surfaces 1 and 2 is 1.40 mm in an uncompressed state. Next, FIG. 14 shows a case where the interval dimension H is 1.32 mm, FIG. 15 shows a case where H is 1.22 mm, and FIG. 16 shows a case where H is 1.12 mm. It is apparent from the FEM analysis diagrams of FIGS. 13 to 16 that the contact pressure P is maintained substantially uniform and appropriate within the range and a stable sealing property (sealability) is exhibited.
[0028]
In other words, the metal seal S according to the present invention is also effective for extremely small seals, for example, as in the above-described prototype, has a small tightening force (at a low load), has a large restoring force, and undergoes plastic deformation. The region up to {the elastic deformation region} is very large. The metal seal S has a large number of straight sections in the cross-sectional shape, is easy and inexpensive to cut, and can sufficiently cope with a small size that is difficult and expensive to process with a metal O-ring.
[0029]
In addition, despite the fact that the metal seal S has a block-shaped cross-sectional shape, the torsion elastic deformation and the like due to falling (rotation) are performed in a complex manner, and sufficient sealing performance with low tightening force ( Demonstrates sealing performance). Utilizing such a low tightening force, it can be used as a sealing material to replace conventional rubber O-rings under severe conditions that cannot be applied with conventional O-rings such as high temperature, low temperature, plasma irradiation and ozone atmosphere. It becomes possible. The SUS316L double melt described above as a material is suitable as a semiconductor manufacturing apparatus that has a small amount of impurities such as carbon and requires high cleanliness.
[0030]
The surface of the present metal seal S will be described as follows: (1) plating of silver, gold, copper, tin, etc., (2) coating of various resins such as PTFE and FEP, and (3) coating (coating) of various rubber materials. , (4) super-polishing finish, (5) cutting, grinding or pressing as it is. The sealed fluid may be vacuum, various gases (CO ₂ , H ₂ , O ₂ , NH ₃ , H ₂ O, etc.), various liquids (H ₂ O, H ₂ SO ₄ , HCl, etc.). In any case, the present metal seal S is an excellent seal in that it has a low tightening force, a large amount of elastic restoration, easy handling, small number of parts, easy manufacturing, and low cost. Accordingly, the mating members (flanges, etc.) 7 and 8 to be mounted can be applied to a brittle material such as ceramic or a soft material such as aluminum, and can be irradiated with plasma or ozone as in a semiconductor manufacturing apparatus. It can be applied to a wide range of temperatures from low to high. Since it is crushable and exhibits sufficient sealing performance (sealing performance) in a wide range of the set height H, it can be applied even if the dimensional accuracy and tolerance of the mating members (flanges, etc.) 7 and 8 to be mounted are rough. In some cases, a common metal seal S can be used for both deep and shallow grooves. Further, since the elastic recovery amount is large, it can be applied to a place where pressure fluctuation and temperature fluctuation are severe, can be reused, and there is an advantage that handling (incorporation) is easy. Further, it is easy to extend the service life by using the upside down.
[0031]
【The invention's effect】
The present invention has the following significant effects by the above configuration.
(According to claim 1) Since it is configured so that torsional elastic deformation is generated as a whole in the mounted and compressed state, the amount of elastic restoration (elastic deformation area) is large, and the wide set height (see FIGS. 14 to 16) (See reference sign H)). Therefore, even if the depth dimension tolerance of the concave portion (concave groove) or the like of the mounting member is large, high sealing performance (sealing performance) can always be exhibited. Further, since it can be used with a low tightening force, it can be applied to a material having a fragile or soft mounting member (flange or the like).
Further, even a small seal having an external dimension of less than 10 mm, which is difficult to manufacture with a metal O-ring, can be manufactured relatively inexpensively, and thus is a practically excellent metal seal. Also, damage to the flat surfaces 1 and 2 can be reduced.
[0032]
In the case where the first and second contact protrusions 11 and 12 rotate (fall down) around the intermediate base 3 and undergo torsional elastic deformation (according to claim 2), the first and second contact protrusions 11 and 12 have a wide set height H. Since the posture is slowly changed as a whole while always stably contacting the flat surfaces 1 and 2, excellent sealing performance (sealing performance) is provided. Moreover, machining by cutting or the like is relatively easy.
(According to claim 3) A stable sealing property (sealability) can be exhibited in a wider range of the set height H. Further, it is difficult to make contact with the flat surface 2 such as the corner portion 15 (see FIGS. 6 and 16), and it is possible to prevent the formation of the air pool (space portion 17).
According to the fourth aspect, even if the mating member 8 to which the second contact projection 12 is pressed against is made of a soft material or a brittle material, the damage can be prevented.
Further, it is possible to prevent the entire seal from falling down too much under the pressing force, and to effectively generate a repulsive force due to torsion.
According to the fifth aspect of the invention, by inverting and using the first installation state and the second installation state (see FIG. 5), the usable period (life) can be extended.
[Brief description of the drawings]
FIG. 1 is a sectional front view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing various embodiments of the present invention.
FIG. 3 is an operation explanatory view of the present invention.
FIG. 4 is a diagram for explaining a conventional problem.
FIG. 5 is a sectional view showing a method of using the apparatus of the present invention.
FIG. 6 is a cross-sectional view showing another embodiment.
FIG. 7 is a cross-sectional view showing still another embodiment.
FIG. 8 is a cross-sectional view showing another embodiment.
FIG. 9 is a cross-sectional view showing still another embodiment.
FIG. 10 is an explanatory diagram of a use state.
FIG. 11 is a cross-sectional view showing another embodiment.
FIG. 12 is a sectional view showing still another embodiment.
FIG. 13 is an explanatory view which is both a cross-sectional view of a main part and a FEM analysis diagram showing a use state of the metal seal of the present invention.
FIG. 14 is an explanatory view which is both a sectional view of a main part and an FEM analysis diagram showing a use state of the metal seal of the present invention.
FIG. 15 is an explanatory view which is both a cross-sectional view of a main part and an FEM analysis diagram showing a use state of the metal seal of the present invention.
FIG. 16 is an explanatory view showing both a sectional view of a main part and an FEM analysis diagram showing a use state of the metal seal of the present invention.
[Explanation of symbols]
1, 2 Flat surface 3 Intermediate base 5, 6 End surface (long side)
7,8 mating member (mounting member)
11 First contact protrusion 12 Second contact protrusion 20, 21 Gap 27 Regulation inner peripheral surface S Metal seal H Interval (set height)

Claims (5)

An intermediate base, a first contact protrusion abutting on one of the flat surfaces, and a second contact surface on the other of the flat surfaces in a generally annular metal seal interposed between a pair of flat surfaces parallel to each other. A second contact protrusion, which comes into contact therewith, the first contact protrusion protrudes near the inner diameter of the intermediate base, and the second contact protrusion protrudes near the outer diameter of the intermediate base, A metal seal configured to generate torsional elastic deformation that rotates about the intermediate base by a pressing force received from the pair of flat surfaces in a mounted and compressed state. 2. The metal seal according to claim 1, wherein the intermediate base is substantially rectangular in cross section, and the first and second contact projections are substantially semicircular to substantially semielliptical in cross section. The intermediate base has a substantially rectangular cross section, and the gap between the end surface of the intermediate base, on which the first contact projection is projected, and one flat surface gradually increases toward the outer diameter in the uncompressed state. Further, the gap between the end surface of the intermediate base, on which the second contact projection is projected, and the other flat surface is formed on an inclined surface that gradually increases toward the inner diameter side in a non-compressed state. The metal seal according to claim 1, wherein the metal seal is formed. The regulating inner peripheral surface portion, the outer peripheral surface of which is in contact with the second contact convex portion in the mounted and compressed state, is connected to the other flat surface so that the second contact convex portion comes into contact at two points in the cross section. The metal seal according to claim 1, wherein the metal seal is formed. A first contact protrusion protruding toward the inner diameter is protruded on one of both end surfaces in the axial direction of the annular metal seal, and a second contact protrusion protruding on the outer diameter is protruded on the other. A first assembled state in which the first contact projection corresponds to one flat surface, and a second assembly in which the second contact projection corresponds to the one flat surface. A metal seal mounting and use method, wherein the metal seal is mounted in an inverted state after a predetermined use period.

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