Composite seal structure and sealing method using the same

Abstract

To prevent the flow of corrosive gas or radical gas toward an elastomer member side while maintaining low fastening force, and to reduce gas permeation from the elastomer member, thereby enhancing sealing performance.SOLUTION: A composite seal structure 1 is sandwiched between a pair of flange parts 10, the composite seal structure comprising: an annular metal member 2 having a recessed groove 2a formed continuously along the entire circumference on either the outer peripheral side or the inner peripheral side; and an elastomer member 3 having a part-to-be-accommodated 3a that is fitted into the recessed groove 2a of the metal member 2, and projecting parts 3b continuous with the part-to-be-accommodated 3a, with which the pair of flange parts 10 comes into contact. Only the projecting parts 3b are brought into contact with the pair of flange parts 10 at the time of non-compression and the start of compression. In a compressed state at or beyond a predetermined compression rate, the projecting parts and the deformed metal member 2 are brought into contact with the pair of flange parts 10, thereby sealing the space between the pair of flange parts 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Conventionally, rubber O-rings have been used to create a vacuum environment in semiconductor manufacturing equipment or surface treatment equipment for liquid crystal panels. However, in radical gas environments or corrosive environments, rubber O-rings have poor corrosion resistance and radical resistance, so it is also known to use a sealing material that has 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 also inevitably allows gases such as the atmosphere to pass through 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 described 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. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4625746 [Patent Document 2] Japanese Patent Publication No. 2023-156213 Summary of the Invention [Problem to be solved by the invention]

[0006] The elasticity of the composite metal seal is set to be approximately equal to that of a rubber O-ring seal, presumably so that the composite metal seal can replace conventional rubber O-ring seals.

[0007] There is a need to improve the sealing performance even further compared to conventional composite seal structures while maintaining such a low fastening force.

[0008] The present invention has been made in consideration of these points, and its object is to improve sealing performance by reducing gas permeation from elastomer members while maintaining a low tightening force. [Means for solving the problem]

[0009] In order to achieve the above object, in this invention, in a moderately compressed state, the elastomer member maintains sealing properties, while the metal member prevents corrosive gases or radical gases from flowing toward the elastomer member.

[0010] Specifically, in the first invention, an annular metal member having a continuous groove formed on the entire periphery of either an outer periphery or an inner periphery; an elastomer member having a received portion that fits into the recessed groove of the metal member and a protruding portion that is continuous with the received portion and against which a pair of flange portions abut, When not compressed and when compression starts, only the protrusions abut on the pair of flanges, When compressed at a predetermined compression rate or more, the protrusions and the deformed metal member come into contact with each other, thereby forming a seal between the pair of flanges.

[0011] According to the above configuration, the elastomer member ensures sealing performance, while the metal member that comes into contact with the pair of flange portions in a compressed state prevents corrosive gases or radical gases from flowing toward the elastomer member, thereby reducing the permeation of gases (such as the atmosphere) from the elastomer member and improving sealing performance.In addition, since the elastomer member ensures sealing performance from the start of compression, the tightening force of the metal member can be reduced.

[0012] In the second invention, in the first invention, When not compressed, the accommodated portion has a semicircular or semi-elliptical cross section, or has a V-shaped groove in cross section.

[0013] According to the above-described configuration, the accommodated portion is appropriately accommodated in the recessed groove of the metal member so as not to come off when uncompressed or compressed.

[0014] In the third sealing method invention, an annular metal member having a continuous groove formed on the entire periphery of either an outer periphery or an inner periphery; a composite seal structure including an elastomer member having a received portion that fits into the recessed groove of the metal member and a protrusion portion that is continuous with the received portion and against which a pair of flange portions abut, the composite seal structure being sandwiched between the pair of flange portions; When not compressed and when compression starts, only the protrusions are brought into contact with the pair of flanges, When compressed to a predetermined compression rate or higher, the protrusion and the deformed metal member are brought into contact with a pair of flange portions, sealing the space between the pair of flange portions, and the metal member reduces gas permeation from the elastomer member while suppressing the flow of corrosive gases or radical gases toward the elastomer member.

[0015] According to the above configuration, while the elastomer member ensures sealing properties, 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 gases or radical gases toward the elastomer member, and since the elastomer member ensures sealing properties from the start of compression, the tightening force of the metal member can be reduced.

[0016] In the fourth invention, in the third invention, The side of the metal member is in an atmosphere of radical gas.

[0017] According to the above 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 to the elastomer member side is suppressed, so that the durability of the elastomer member is remarkably improved.

[0018] In the fifth invention, in the third or fourth invention, The maximum tightening force during compression is 3.9 N / mm or more and 25 N / mm or less.

[0019] According to the above configuration, since the sealing performance is ensured by the elastomer member, the maximum tightening force of the metal member can be kept lower than that of the metal seal. On the other hand, while suppressing the flow of corrosive gas or radical gas to the elastomer member side by the metal member in contact with the pair of flange portions in a compressed state with an appropriate tightening force, the gas permeation from the elastomer member can be reduced.

[0020] In the sixth invention, in any one of the third to fifth inventions, The side of the elastomer member is used in an atmosphere of -80°C or higher and 250°C or lower.

[0021] According to the above configuration, a wide selection of elastomer members from low temperature to high temperature becomes possible.

Effect of the Invention

[0022] As described above, according to the present invention, while maintaining the sealing performance with the elastomer member and suppressing the flow of corrosive gas or radical gas to the elastomer member side by the metal member, the gas permeation from the elastomer member is reduced. Therefore, the sealing performance can be improved while keeping the tightening force low.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0025] FIG. 1 and FIG. 2 show the composite seal structure 1 of an embodiment of the present invention. This composite seal structure 1 includes an annular metal member 2 in which a concave groove 2a continuous in the entire circumference on the outer peripheral side is formed.

[0026] In this embodiment, the cross-section of the metal member 2 is a substantially semi-circular shape that opens to the outer peripheral side. However, as shown in FIGS. 5(a) to 5(d), it may have various shapes with the concave groove 2a. The metal member 2 is made of stainless steel (such as SUS316L, SUS304, etc.), nickel alloy (such as C22, C276, 718, etc.), titanium, aluminum alloy, copper alloy, etc. Molded products with different wall thicknesses may be used, or press-molded products with a constant plate thickness t may also be used. The plate thickness t is 0.15 to 0.60 mm, preferably 0.20 to 0.30 mm. The height h2 is 2 to 7 mm, preferably 2.8 to 3.8 mm.

[0027] The composite seal structure 1 further includes an elastomer member 3 having a received portion 3a that fits into the concave groove 2a of the metal member 2 and a protruding portion 3b where a pair of flange portions 10 are in contact with the received portion 3a continuously. The received portion 3a of the elastomer member 3 when not compressed is semi-circular in shape in this embodiment.

[0028] In this embodiment, the received portion 3a is formed on the inner peripheral side over the entire circumference. However, when the metal member 2 is provided on the outer peripheral side, the received portion 3a may be provided on the outer peripheral side.

[0029] 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), etc.

[0030] The outer diameter ID of the elastomer member 3 is 20 to 1270 mm, preferably 300 to 700 mm, and the height h1 is 2.2 to 7.5 mm, preferably 3 to 4 mm. The radial width w0 of the protruding portion 3b is, for example, 1.1 mm, but is not limited thereto. The radial width W of the cross-section of the composite seal structure 1 is 2 to 12 mm, preferably 2.5 to 4 mm.

[0031] And, as will be described in detail later, the height h2 of the metal member 2 in the non-compressed state is set to be lower than the height h1 of the elastomer member 3 (h2 < h1) so that only the protruding strip portion 3b contacts the pair of flange portions 10 when the composite seal structure 1 is not compressed and at the start of compression.

[0032] And, as will be described in detail later, in a compressed state with a predetermined compression ratio or more, the protruding strip portion 3b and the deformed metal member 2 come into contact with each other so that the space between the pair of flange portions 10 is sealed.

[0033] In this embodiment, the housed portion 3a in the non-compressed state is semi-circular, but as shown in FIGS. 7(b) to 7(d), it may have a semi-elliptical cross-sectional shape or a shape having a V-shaped groove in cross-section.

[0034] -Finite Element Method Analysis- An analysis was performed on the relationship between the compression ratio and the tightening force of the composite seal structure 1 using finite element method analysis software.

[0035] The units were set as follows: length in mm, Young's modulus in MPa, and force in N. Based on static analysis and non-linear structural analysis (contact, large deformation), and utilizing the symmetry of the composite seal structure 1, the analysis was performed using a 1 / 2 axisymmetric model as shown in FIG. 3.

[0036] Regarding the composite seal structure 1, it was assumed that the rigidity of the pair of flange portions 10 was sufficiently high, and the pair of flange portions 10 were treated as rigid bodies. The large deformation effect was considered for the analysis implementation from the deformation amount and contact with friction. The compression ratio was calculated based on the height of the composite seal structure 1 in the non-compressed state, that is, the height h1 of the elastomer member in the non-compressed state.

[0037] In this analysis, for the elastomer member 3, the physical property values of silicone rubber with a hardness of 70 were used, and for the metal member 2, the physical property values of SUS316L were used.

[0038] As described above, since the height h2 of the metal member 2 when not compressed is set lower than the height h1 of the elastomer member 3 (h2 < h1), as shown in Fig. 4, three lines are shown for only the elastomer member 3, only the metal member 2, and the composite seal structure 1. At a compression rate of around 5%, the metal member 2 begins to contact the pair of flange portions 10. And it can be seen that the tightening force of the composite seal structure 1 suddenly increases around that point. The sealing property is ensured by the elastomer member 3 from the start of compression.

[0039] That is, it shows that what was initially in contact with the pair of flange portions 10 was only the upper and lower elastomer members 3, and around a compression rate of 5%, the metal member 2 also had its outer periphery in contact with the pair of flange portions 10.

[0040] And around a compression rate of 7.5%, the tightening force increases linearly. It can be seen that after 7.5%, both the metal member 2 and the elastomer member 3 are stably in contact with the pair of flange portions 10 and exhibit sealing performance.

[0041] When the target fastening force was reached, the compression rate was about 22% and the maximum fastening force was 7.1 N / mm.

[0042] A similar analysis was performed for the case where the metal member 2 has the shapes shown in Figs. 5(a) to (d), and for the case where the elastomer member 3 has the shape shown in Fig. 7(a).

[0043] In any shape, as shown in Fig. 6, an appropriate tightening force was obtained. The examples shown in Figs. 3 and 4 are (a)-4 in Fig. 6. It was found that an appropriate tightening force can be obtained with an appropriate shape of the metal member 2 and an appropriate plate thickness t and height h2.

[0044] -Sealing method using a composite seal structure- The composite seal structure 1 described above is sandwiched between a pair of flange portions 10. There are no particular limitations on the equipment in which it can be used, but it can be used, for example, in a portion of a semiconductor manufacturing device or a surface treatment device for liquid crystal panels that connects gas or liquid flow passages and seals the inside and outside of the flow passages at the pair of flange portions 10.

[0045] When not compressed, only the upper and lower protrusions 3b of the elastomer member 3 abut against the pair of flanges 10, respectively. In this embodiment, for example, the composite seal structure 1 is used such that the inner circumferential side (inside the flow passage) of the metal member 2 is in a radical gas atmosphere, and the outer 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 from the start of compression, sealing performance is reliably ensured.

[0046] Next, as the compression ratio is gradually increased, for example, as described above, at a compression ratio of around 5%, the metal member 2 also begins to abut against the pair of flange portions 10, 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.

[0047] As a result, with an appropriate tightening force, the composite seal structure 1 seals between the pair of flange portions 10, and the metal member 2 prevents radical gas from flowing toward the elastomer member 3, while reducing gas permeation from the elastomer member 3.

[0048] It is desirable that the maximum clamping force during compression be kept between 3.9 N / mm and 25 N / mm. In other words, because the flexible elastomer member 3 ensures sealing performance, the maximum clamping force can be kept lower than that of a single metal seal.

[0049] In this way, while ensuring the sealing property with the elastomer member 3, the permeation of gas from the elastomer member 3 can be reduced while suppressing the flow of radical gas to the elastomer member 3 side by the metal member 2 in contact with the pair of flange portions 10 in a compressed state. Also, since the elastomer member 3 ensures the sealing property, the tightening force of the metal member 2 can be lowered.

[0050] Further, at the time of compression, since the metal member 2 is in contact with the pair of flange portions 10 with an appropriate tightening force, the flow of radical gas into the elastomer member 3 is effectively suppressed, and the durability of the elastomer member 3 is remarkably improved.

[0051] Also, if the outer peripheral side of the elastomer member 3 is within an atmosphere of -80°C or higher and 250°C or lower, depending on the application, a wide range of the elastomer member 3 as described above can be selected.

[0052] Furthermore, since the concave groove 2a of the metal member 2 wraps around the housed portion 3a of the elastomer member 3 over the entire circumference, the housed portion 3a is appropriately housed so as not to easily come off within the concave groove 2a of the metal member 2 during non-compression and compression.

[0053] Therefore, according to the composite seal structure 1 according to the present embodiment, while maintaining the sealing property with the elastomer member 3 and suppressing the flow of corrosive gas or radical gas to the elastomer member 3 side by the metal member 2, the permeation of gas from the elastomer member 3 is reduced. Thus, the sealing performance can be improved while keeping the tightening force low.

[0054] -Effect confirmation by helium leak test- FIG. 8 is a graph showing the results of a helium leak test using the composite seal structure 1 of the embodiment of the present invention.

[0055] The test temperature was 22°C, the flow rate of helium was 50 mL / min (hood method), and the compression ratio was based on the initial height h1 = 3.60 mm of the seal.

[0056] Although details are not shown, the composite seal structure 1 was placed between a pair of flanges 10 in a press machine and compressed. The amount of leakage was monitored using a helium leak detector, and a stable state was used as the background. Tape was wrapped around the outer periphery of the pair of flanges 10 to form a hood (leaving a helium injection port). The amount of leakage was monitored for 10 minutes after helium began to be blown into the injection port. The amount of leakage when it stabilized was recorded as the saturated leakage amount.

[0057] As a comparative example, a seal equivalent to that of only the elastomer member 3 without the metal member 2 was also recorded in the same manner.

[0058] As can be seen from FIG. 8, the amount of leakage from the composite seal structure 1 was smaller than that from the elastomer member 3 alone, regardless of whether the compression ratio was 10%, 20%, or 22%.

[0059] -Confirming the effect through radical resistance testing- Although not shown, a radical exposure tester was used as the tester. The gas conditions were O2 + CF4 (2:1), the pressure inside the processing chamber was 100 Pa, and the microwave output was 2500 W. The compression ratio was based on the initial height h1 of the composite seal structure 1, which was 3.60 mm.

[0060] The radical resistance effect was confirmed only for the composite seal structure 1 and the elastomer member 3 as a comparative example.

[0061] As shown in Figure 8, there was no weight loss (wear and tear of the elastomer member 3) in the composite seal structure 1, which confirmed that combining it with the metal member 2 was effective in improving radical resistance. On the other hand, when only the elastomer member 3 was used, it was found that significant wear and tear of the elastomer material occurred.

[0062] (Other embodiments) The present invention may be configured as follows in relation to the above-described embodiment.

[0063] That is, in the above-described embodiment, the metal member 2 is provided on the inner peripheral side. However, when the outer peripheral side is in an environment such as a radical gas, it is provided on the outer peripheral side. In this case, the elastomer member 3 is fitted into the concave groove 2a on the inner peripheral side from the inner peripheral side.

[0064] 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

[0065] 1 Composite seal structure 2 Metal member 2a Concave groove 3 Elastomer member 3a Accommodated portion 3b Ridge portion 10 Flange portion

Claims

1. An annular metal member having a concave groove formed continuously around the entire outer circumference or inner circumference, and an elastomeric member having a received portion that fits into the concave groove of the metal member and a protruding portion where a pair of flange portions abut continuously to the received portion, wherein only the protruding portion abuts against the pair of flange portions at the time of non-compression and at the start of compression, and configured such that the protruding portion and the deformed metal member come into contact in a compressed state with a compression ratio equal to or higher than a predetermined value, and the space between the pair of flange portions is sealed. A composite seal structure characterized by the above.

2. The received portion at the time of non-compression has a semi-circular or semi-elliptical cross-section, or has a groove with a V-shaped cross-section. The composite seal structure according to claim 1, characterized by the above.

3. An annular metal member having a concave groove formed continuously around the entire outer circumference or inner circumference, and sandwiching a composite seal structure including an elastomeric member having a received portion that fits into the concave groove of the metal member and a protruding portion where a pair of flange portions abut continuously to the received portion between the pair of flange portions, bringing only the protruding portion into contact with the pair of flange portions at the time of non-compression and at the start of compression, bringing the protruding portion and the deformed metal member into contact with the pair of flange portions in a compressed state with a compression ratio equal to or higher than a predetermined value, sealing the space between the pair of flange portions, and reducing gas permeation from the elastomeric member while suppressing the flow of corrosive gas or radical gas to the elastomeric member side by the metal member. A sealing method using the composite seal structure characterized by the above.

4. The side of the metal member is in an atmosphere of radical gas. The sealing method using the composite seal structure according to claim 3, characterized by the above.

5. The maximum tightening force during compression is 3.9 N / mm or more and 25 N / mm or less. The sealing method using the composite seal structure according to claim 3 or 4, characterized by the above.

6. The side of the elastomeric member is used in an atmosphere of -80°C or higher and 250°C or lower. The sealing method using the composite seal structure according to claim 3 or 4, characterized by the above.

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