Gas filter device

Abstract

To provide a gas filter device in which an end part in an axial direction can be reliably sealed even if a ceramic filter and a seal member have mass production errors.SOLUTION: A gas filter device 1 includes a ceramic filter 2, and a seal member 3 made of resin. The seal member 3 comprises a concave part 4 into which an end part 2c of the ceramic filter 2 is inserted. The concave part 4 includes: a first surface 4a opposed to an outer surface 2a of the ceramic filter 2, and extending in a circumferential direction; a second surface 4b opposed to an inner surface 2b of the ceramic filter 2, and extending in the circumferential direction; and a bottom surface 4c connecting the first surface 4a and the second surface 4b. The first surface 4a is provided with a first seal part 5a in contact with the outer surface 2a of the ceramic filter 2. The second surface 4b is provided with a second seal part 5b in contact with the inner surface 2b of the ceramic filter 2. The second seal part 5b is provided closer to the side of the bottom surface 4c than the first seal part 5a.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas filter device for filtering gas.

Background Art

[0002] Conventionally, a gas filter device including a ceramic filter used in a semiconductor manufacturing apparatus or the like is known. For example, Patent Document 1 below proposes a gas filter composed of a cylindrical ceramic filter, a seal member for sealing its end portion, and an elastic member for urging the seal member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the gas filter device of Patent Document 1, due to variations in the manufacturing of the ceramic filter and the seal member, so-called mass production errors, gas may leak from the axial end portions, and there has been a strong demand for improvement in the airtightness at the end portions of the ceramic filter.

[0005] The present invention has been devised in view of the above actual situation, and the main object thereof is to provide a gas filter device that can reliably seal the axial end portions even for a ceramic filter and a seal member having mass production errors.

Means for Solving the Problems

[0006] The present invention relates to a gas filter device for filtering gas, comprising a ceramic filter and a resin sealing member, wherein the ceramic filter has a cylindrical shape with axial, radial, circumferential, radial outer surface, radial inner surface and a pair of axial ends, the sealing member seals at least one of the axial ends of the ceramic filter and has a recess into which the end of the ceramic filter is inserted, the recess comprising a first surface extending circumferentially opposite the outer surface of the ceramic filter, a second surface extending circumferentially opposite the inner surface of the ceramic filter, and a bottom surface connecting the first surface and the second surface, the first surface being provided with a first sealing portion that contacts the outer surface of the ceramic filter, and the second surface being provided with a second sealing portion that contacts the inner surface of the ceramic filter, the second sealing portion being provided on the bottom surface side of the first sealing portion. [Effects of the Invention]

[0007] By having the above-described configuration, the gas filter device of the present invention can reliably seal the axial end of the ceramic filter even if the ceramic filter and sealing member have production tolerances. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view showing one embodiment of the gas filter device of the present invention. [Figure 2] This is a cross-sectional view of the sealing member. [Figure 3] This is an enlarged view of section A in Figure 2. [Figure 4] This is a front view of the sealing member. [Figure 5] This is an enlarged cross-sectional view of a sealing member of another embodiment. [Modes for carrying out the invention]

[0009] One embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 is a cross-sectional view showing the gas filter device 1 of this embodiment. As shown in Figure 1, the gas filter device 1 of this embodiment is for filtering gas G used in semiconductor manufacturing equipment (not shown) and the like. The gas filter device 1 is preferably used as an inline filter, for example.

[0010] The gas filter device 1 of this embodiment includes a ceramic filter 2 and a resin sealing member 3. The gas filter device 1 is housed, for example, in a metal housing (not shown) made of stainless steel or the like, which constitutes the outer casing. However, when the gas filter device 1 is used, for example, as a diffuser mounted in a vacuum chamber, the housing may be omitted.

[0011] The ceramic filter 2 of this embodiment has a cylindrical shape with axial, radial, circumferential, and radial outer surfaces 2a, a radial inner surface 2b, and a pair of axial ends 2c. For example, gas G flows into the cylindrical interior of the ceramic filter 2 from one end 2c and flows out radially to the outside.

[0012] Figure 2 is a cross-sectional view of the sealing member 3. As shown in Figure 2, the sealing member 3 seals at least one, in this embodiment both, ends 2c of the ceramic filter 2 in the axial direction. Preferably, the sealing member 3 has a recess 4 into which the ends 2c of the ceramic filter 2 are inserted. Such a sealing member 3 can suppress gas G leakage from the ends 2c of the ceramic filter 2 with a simple configuration and also helps to reduce manufacturing costs.

[0013] Figure 3 is an enlarged view of part A in Figure 2. As shown in Figures 2 and 3, the recess 4 of this embodiment includes a first surface 4a extending circumferentially opposite the outer surface 2a of the ceramic filter 2, and a second surface 4b extending circumferentially opposite the inner surface 2b of the ceramic filter 2. It is preferable that the recess 4 includes a bottom surface 4c connecting the first surface 4a and the second surface 4b.

[0014] The first surface 4a of this embodiment is provided with a first sealing portion 5a that contacts the outer surface 2a of the ceramic filter 2. The second surface 4b of this embodiment is provided with a second sealing portion 5b that contacts the inner surface 2b of the ceramic filter 2. The first sealing portion 5a and the second sealing portion 5b can sandwich the ceramic filter 2 from both sides of the outer surface 2a and the inner surface 2b, thereby improving the airtightness at the end 2c of the ceramic filter 2.

[0015] In this embodiment, the second sealing portion 5b is provided on the bottom surface 4c side than the first sealing portion 5a. As a result, when the ceramic filter 2 is inserted into the recess 4, the first sealing portion 5a and the second sealing portion 5b contact the ceramic filter 2 in the order of the first sealing portion 5a and then the second sealing portion 5b. Such a sealing member 3 has a large tolerance for dimensional errors in the ceramic filter 2 and the sealing member 3.

[0016] Therefore, the gas filter device 1 of this embodiment can reliably seal the axial end 2c of the ceramic filter 2 even if the ceramic filter 2 and sealing member 3 have production tolerances. As a result, the gas filter device 1 of this embodiment can be used as a product even if the ceramic filter 2 and sealing member 3 have production tolerances due to variations during manufacturing, thereby suppressing a decrease in yield and reducing manufacturing costs.

[0017] In a more preferred embodiment, the ceramic filter 2 is a porous filter having a pore size of 1 to 10 μm. The ceramic filter 2 is formed from, for example, zirconia, alumina, or the like. Such a ceramic filter 2 has excellent corrosion resistance to corrosive gases G such as chlorine gas, and helps to improve the durability of the gas filter device 1.

[0018] As shown in Fig. 1, the seal member 3 of the present embodiment includes a pair of seal members 3 for sealing both axial ends 2c of the ceramic filter 2. Such a seal member 3 can suppress the leakage of the gas G from both axial ends 2c of the ceramic filter 2.

[0019] The gas filter device 1 of the present embodiment includes a support 6 disposed radially inside the inner surface 2b of the ceramic filter 2, a pair of protective members 7 disposed axially outside the support 6 and the ceramic filter 2, and a joint 8 for allowing the gas G to flow in.

[0020] The support 6 is formed, for example, from a metal punching metal such as stainless steel provided with a plurality of through holes 6a. The diameter d of each of the plurality of through holes 6a is preferably 1.0 to 2.0 mm. The support 6 of the present embodiment is formed in a cylindrical shape. Such a support 6 is suitable for discharging the gas G evenly in the radial direction.

[0021] Note that the support 6 is not limited to such a form, and for example, it may be an elliptical cylinder shape or a polygonal cylinder shape. Similarly, the shape of the through hole 6a is not limited to such a form, and as long as the gas G can be discharged evenly and the strength of the support 6 can be maintained, for example, it may be an elliptical shape, a polygonal shape, a slit shape, etc., and its size and number can also be adjusted as appropriate.

[0022] The protective member 7 is formed, for example, from a metal such as stainless steel. It is desirable that the support 6 and the protective member 7 are fixed to each other by welding. Such a support 6 and protective member 7 can hold the ceramic filter 2 and the seal member 3, and can improve the sealing performance and durability of the gas filter device 1.

[0023] Preferably, each of the pair of protective members 7 has a cylindrical portion 7a located radially outward from each of the pair of sealing members 3, and a bottom portion 7b located axially outward from each of the pair of sealing members 3. The cylindrical portion 7a includes, for example, a tapered structure in which its inner diameter continuously decreases toward the bottom portion 7b.

[0024] Such protective member 7 can be easily assembled even when the ceramic filter 2, sealing member 3, and protective member 7 have production tolerances, thereby suppressing a decrease in yield and helping to reduce the manufacturing cost of the gas filter device 1.

[0025] The protective member 7 includes, for example, a first protective member 7A disposed on one axial side of the ceramic filter 2 and a second protective member 7B disposed on the other axial side of the ceramic filter 2. It is desirable that the cylindrical portion 7a of the first protective member 7A and the cylindrical portion 7a of the second protective member 7B have the same shape. Such a protective member 7 can stably hold the sealing member 3.

[0026] The joint 8 is made of a metal such as stainless steel. In this embodiment, the joint 8 is connected to the bottom 7b of the first protective member 7A. Preferably, the joint 8 has an inlet 8a into which gas G can flow. The joint 8 is connected, for example, to a flow path, container, etc., upstream of the gas filter device 1. Such a joint 8 can allow gas G to flow smoothly into the gas filter device 1 and also has excellent durability.

[0027] As shown in Figures 1 to 3, each of the pair of sealing members 3 in this embodiment includes an outer peripheral surface 3a facing the cylindrical portion 7a of the protective member 7. Preferably, the outer peripheral surface 3a has a third sealing portion 5c that contacts the cylindrical portion 7a. Such a third sealing portion 5c works in cooperation with the tapered cylindrical portion 7a to suppress the leakage of gas G from between the sealing member 3 and the protective member 7.

[0028] The third sealing portion 5c is located on the bottom surface 4c side of the first sealing portion 5a. Such a sealing member 3 helps to suppress stress concentration due to elastic deformation during sealing and improves durability.

[0029] The first sealing portion 5a of the sealing member 3 includes at least one projection structure, in this embodiment, on a part of the first surface 4a that protrudes toward the outer surface 2a of the ceramic filter 2. Similarly, the third sealing portion 5c of the sealing member 3 preferably includes at least one projection structure on a part of the outer peripheral surface 3a that protrudes radially outward. Such a sealing member 3 allows the sealing position to be set at the position of the projection structure, and can reliably seal the end 2c of the ceramic filter 2.

[0030] The protruding heights h1 and h2 of the protruding structures are preferably 5% to 40% of the radial thickness t from the first surface 4a to the outer peripheral surface 3a. Having protruding heights h1 and h2 of 5% or more of the thickness t ensures reliable sealing performance due to elastic deformation. From this viewpoint, the protruding heights h1 and h2 of the protruding structures are more preferably 10% or more of the thickness t. Having protruding heights h1 and h2 of 40% or less of the thickness t allows for easy assembly even when the ceramic filter 2, sealing member 3, and protective member 7 have production tolerances. From this viewpoint, the protruding heights h1 and h2 of the protruding structures are more preferably 30% or less of the thickness t.

[0031] In this embodiment, the protrusion height h1 of the first seal portion 5a and the protrusion height h2 of the third seal portion 5c are equal. Such a seal member 3 can improve sealing performance uniformly on both the first surface 4a side and the outer peripheral surface 3a side. However, the protrusion height h1 of the first seal portion 5a and the protrusion height h2 of the third seal portion 5c may be different from each other.

[0032] The projection structure, for example, has a cross-sectional shape that is approximately semicircular. The radius of curvature of the cross-section of the projection structure in this embodiment is equal to the projection heights h1 and h2 of the projection structure. Such a projection structure can achieve both ease of assembly and sealing performance due to elastic deformation. However, the projection structure is not limited to this embodiment; for example, the radius of curvature may be larger than the projection heights h1 and h2, and the cross-sectional shape may be a semi-ellipse, trapezoid, triangle, or other polygon.

[0033] Figure 4 is a front view of the sealing member 3 as seen from the recess 4 side. As shown in Figures 1 to 4, it is desirable that the projection structures of the first sealing portion 5a and the third sealing portion 5c have a ring shape that extends continuously in the circumferential direction. Such a sealing member 3 can seal over the entire circumferential area, thereby further improving the sealing performance.

[0034] The second seal portion 5b preferably includes a tapered structure in which the inner diameter of the second surface 4b of the recess 4 continuously decreases toward the bottom surface 4c. Such a second seal portion 5b can be easily assembled even when the ceramic filter 2 or the seal member 3 has production tolerances, and can exhibit excellent sealing performance.

[0035] In this embodiment, the axial length L1 of the first surface 4a is greater than the axial length L2 of the second surface 4b. Such a recess 4 facilitates alignment when the ceramic filter 2 is inserted, and allows for easy assembly even when the ceramic filter 2 or sealing member 3 have production tolerances.

[0036] The sealing member 3 is preferably made of fluororesin. Such a sealing member 3 has excellent elasticity, allowing the first sealing portion 5a, the second sealing portion 5b, and the third sealing portion 5c to elastically deform and seal, thereby improving sealing performance. Furthermore, this sealing member 3 has excellent corrosion resistance to corrosive gases G such as chlorine gas, which helps to improve the durability of the gas filter device 1.

[0037] Examples of fluororesins include polytetrafluoroethylene (PTFE) and perfluoroalkoxyalkanes (PFA). In this embodiment, the fluororesin is polytetrafluoroethylene (PTFE). Such a sealing member 3 has excellent heat resistance and chemical resistance, and can maintain high sealing performance for a long period of time even when filtering corrosive gas G in a high-temperature environment.

[0038] Next, the assembly method of the gas filter device 1 of this embodiment will be described. In the assembly method of the gas filter device 1, it is preferable that a first step S1 is performed in which the support body 6 and the second protective member 7B are fixed together by welding or the like to form the first member.

[0039] The assembly method for the gas filter device 1 includes, for example, a second step S2 in which, following the first step S1, a sealing member 3 is inserted into both ends 2c of the ceramic filter 2 to form a second member. In the second step S2, for example, a press machine is used to insert the sealing member 3 into the ends 2c of the ceramic filter 2. Note that the second step S2 is performed independently of the first step S1, so it may be performed before the first step S1, or the first step S1 and the second step S2 may be performed simultaneously.

[0040] In the assembly method of the gas filter device 1 of this embodiment, following the first step S1 and the second step S2, a third step S3 is performed in which the first member and the second member are assembled to form a third member. Preferably, following the third step S3, a fourth step S4 is performed in which the first protective member 7A is assembled to the third member to form a fourth member. In the fourth step S4, for example, the fourth member is formed by press-fitting the sealing member 3 into the first protective member 7A and the second protective member 7B using a press machine.

[0041] In the assembly method of the gas filter device 1, it is preferable that, following the fourth step S4, a fifth step S5 is performed in which the support body 6 and the first protective member 7A are fixed together by welding or the like to integrate the fourth member. In the assembly method of the gas filter device 1 of this embodiment, following the fifth step S5, a sixth step S6 is performed in which the joint 8 is fixed to the fourth member by welding or the like to obtain the gas filter device 1.

[0042] Figure 5 is an enlarged cross-sectional view of the sealing member 10 of another embodiment. The sealing member 10 of this embodiment, like the sealing member 3 described above, seals the end portion 2c (shown in Figure 1) of the ceramic filter 2. As shown in Figure 5, the sealing member 10 of this embodiment, like the sealing member 3 described above, has an outer peripheral surface 10a facing the cylindrical portion 7a (shown in Figure 1) of the protective member 7, and a recess 11 into which the end portion 2c of the ceramic filter 2 is inserted.

[0043] The recess 11 preferably includes, similar to the recess 4 described above, a first surface 11a extending circumferentially facing the outer surface 2a of the ceramic filter 2, a second surface 11b extending circumferentially facing the inner surface 2b of the ceramic filter 2, and a bottom surface 11c connecting the first surface 11a and the second surface 11b.

[0044] In this embodiment, the first surface 11a is provided with a first sealing portion 12a that contacts the outer surface 2a of the ceramic filter 2, similar to the first surface 4a described above. In this embodiment, the second surface 11b is provided with a second sealing portion 12b that contacts the inner surface 2b of the ceramic filter 2, similar to the second surface 4b described above. In this embodiment, the outer peripheral surface 10a is provided with a third sealing portion 12c that contacts the cylindrical portion 7a of the protective member 7, similar to the outer peripheral surface 3a described above.

[0045] The first seal portion 12a preferably includes a plurality of protruding structures in the axial direction of the ceramic filter 2. In this embodiment, the first seal portion 12a includes a first protrusion 12d, a second protrusion 12e, and a third protrusion 12f. Such a first seal portion 12a, with its triple seal structure, can more reliably seal the axial end 2c of the ceramic filter 2 even if the ceramic filter 2 or the sealing member 10 has production tolerances. Note that the first seal portion 12a is not limited to a triple seal structure; it may be a double seal structure, or even a quadruple or more seal structure.

[0046] It is desirable that the multiple protruding structures have different cross-sectional shapes. In this embodiment, the protruding heights h3, h4, and h5 of the first protrusion 12d, second protrusion 12e, and third protrusion 12f are different from each other. In this embodiment, the protruding height h4 of the second protrusion 12e is greater than the protruding height h3 of the first protrusion 12d and less than the protruding height h5 of the third protrusion 12f.

[0047] Such a first seal portion 12a can be assembled smoothly even if the ceramic filter 2 or the sealing member 10 has production tolerances, thus achieving both ease of assembly and sealing performance. The multiple protrusion structures are not limited to this configuration; for example, the protrusion height h3 of the first protrusion 12d may be greater than the protrusion height h5 of the third protrusion 12f. Furthermore, the cross-sectional shapes of the multiple protrusion structures may differ from each other, for example, the first protrusion 12d, the second protrusion 12e, and the third protrusion 12f may be triangular, semicircular, and trapezoidal, respectively. Even if the cross-sectional shapes of the multiple protrusion structures are the same, the effects of the multiple sealing structures can be similarly achieved.

[0048] The projection structure of the third sealing portion 12c may be different from, for example, the first projection 12d, the second projection 12e, and the third projection 12f. In this embodiment, the projection height h6 of the third sealing portion 12c is greater than the projection height h5 of the third projection 12f. Such a sealing member 10 can improve sealing performance by having multiple sealing structures on the first surface 11a side and by having a large projection structure on the outer peripheral surface 10a side. The cross-sectional shape of the third sealing portion 12c may be equal to the cross-sectional shape of any of the first projection 12d, the second projection 12e, or the third projection 12f.

[0049] Although particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the embodiments described above and can be implemented in various modified forms.

[0050] [Note] The present invention is as follows:

[0051] [Invention 1] A gas filter device for filtering gases, It includes a ceramic filter and a resin sealing member, The ceramic filter has a cylindrical shape that defines the axial direction, radial direction, circumferential direction, radial outer surface, radial inner surface, and a pair of axial ends. The sealing member seals at least one axial end of the ceramic filter and has a recess into which the end of the ceramic filter is inserted. The recess includes a first surface extending circumferentially opposite the outer surface of the ceramic filter, a second surface extending circumferentially opposite the inner surface of the ceramic filter, and a bottom surface connecting the first surface and the second surface. The first surface is provided with a first sealing portion that contacts the outer surface of the ceramic filter. The second surface is provided with a second sealing portion that contacts the inner surface of the ceramic filter. The second sealing portion is provided on the bottom side of the first sealing portion. Gas filter device.

[0052] [2nd Invention] The gas filter device according to the present invention 1, wherein the first sealing portion includes at least one projection structure on which a part of the first surface protrudes toward the outer surface side of the ceramic filter.

[0053] [Invention 3] The gas filter device according to the present invention, wherein the projection structure has a ring shape that extends continuously in the circumferential direction.

[0054] [4th Invention] The gas filter device according to the present invention 2 or 3, wherein the first sealing portion includes a plurality of the projection structures in the axial direction of the ceramic filter.

[0055] [5th ​​Invention] The gas filter device according to the present invention, wherein the plurality of protruding structures have different cross-sectional shapes.

[0056] [Invention 6] The gas filter device according to any one of inventions 1 to 5, wherein the second sealing portion includes a tapered structure in which the inner diameter of the second surface continuously decreases toward the bottom surface.

[0057] [7th Invention] A gas filter device according to any one of inventions 1 to 6, wherein the axial length of the first surface is greater than the axial length of the second surface.

[0058] [8th Invention] The sealing member is formed from a fluororesin, as described in any one of inventions 1 to 7.

[0059] [Invention 9] The gas filter device according to the present invention, wherein the fluororesin is polytetrafluoroethylene.

[0060] [Invention 10] The gas filter apparatus according to any one of inventions 1 to 9, wherein the sealing member includes a pair of sealing members for sealing both axial ends of the ceramic filter.

[0061] [Invention 11] The gas filter device according to the present invention 10, comprising a cylindrical support disposed radially inward of the inner surface of the ceramic filter, and a pair of protective members disposed axially outward of the support and the ceramic filter.

[0062] [Invention 12] Each of the pair of protective members has a cylindrical portion located radially outward from each of the pair of sealing members, Each of the pair of sealing members includes an outer circumferential surface facing the cylindrical portion, The outer circumferential surface has a third sealing portion that contacts the cylindrical portion, as described in invention 11. [Explanation of Symbols]

[0063] 1. Gas filter device 2 Ceramic filter 2a Exterior 2b Inner Self 2c end 3. Sealing member 4 recesses 4a 1st page 4b 2nd side 4c Bottom 5a First seal section 5b Second seal section

Claims

1. A gas filter device for filtering gases, It includes a ceramic filter and a resin sealing member, The ceramic filter has a cylindrical shape that defines the axial direction, radial direction, circumferential direction, radial outer surface, radial inner surface, and a pair of axial ends. The sealing member seals at least one axial end of the ceramic filter and has a recess into which the end of the ceramic filter is inserted. The recess includes a first surface extending circumferentially opposite the outer surface of the ceramic filter, a second surface extending circumferentially opposite the inner surface of the ceramic filter, and a bottom surface connecting the first surface and the second surface. The first surface is provided with a first sealing portion that contacts the outer surface of the ceramic filter. The second surface is provided with a second sealing portion that contacts the inner surface of the ceramic filter. The second sealing portion is provided on the bottom side of the first sealing portion, The first sealing portion is a projection structure in which a part of the first surface protrudes toward the outer surface side of the ceramic filter. Gas filter device.

2. The gas filter device according to claim 1, wherein the projection structure has a ring shape that extends continuously in the circumferential direction.

3. The gas filter apparatus according to claim 1 or 2, wherein the first sealing portion includes a plurality of the protruding structures in the axial direction of the ceramic filter.

4. The gas filter device according to claim 3, wherein the plurality of protruding structures have different cross-sectional shapes.

5. The gas filter device according to claim 1 or 2, wherein the second surface has a tapered structure in which the inner diameter continuously decreases toward the bottom surface.

6. The gas filter apparatus according to claim 1 or 2, wherein the axial length of the first surface is greater than the axial length of the second surface.

7. The gas filter device according to claim 1 or 2, wherein the sealing member is formed from a fluororesin.

8. The gas filter device according to claim 7, wherein the fluororesin is polytetrafluoroethylene.

9. The gas filter apparatus according to claim 1 or 2, wherein the sealing member includes a pair of sealing members for sealing both axial ends of the ceramic filter.

10. The gas filter device according to claim 9, further comprising a cylindrical support disposed radially inward of the inner surface of the ceramic filter, and a pair of protective members disposed axially outward of the support and the ceramic filter.

11. Each of the pair of protective members has a cylindrical portion located radially outward from each of the pair of sealing members, Each of the pair of sealing members includes an outer circumferential surface facing the cylindrical portion, The outer circumferential surface has a third sealing portion that contacts the cylindrical portion, The gas filter device according to claim 10, wherein the third sealing portion is a projection structure in which a part of the outer peripheral surface protrudes radially outward.

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