Metal fiber filter, filter unit, and vaporizer

Abstract

To provide a metal fiber filter or the like that can suppress the retention of fluid at the end of the filter medium. 【Solution means】The metal fiber filter 1 includes a support 2 having a cylindrical shape and a first end E1, a filter medium 3 disposed on the outer side in the radial direction of the support, and a first end member 4 fixed to the side of the first end E1 of the support. The support includes a first support portion 11 having a first outer diameter D1 and a second support portion 12 having a second outer diameter D2 larger than the first outer diameter D1. A plurality of through holes 11a are formed in the first support portion. The filter medium is a sintered body of metal fibers and includes a media body 30 disposed on the outer side in the radial direction of the first support portion and on the outer side in the radial direction of the second support portion, and a first extension portion 31 joined to the first end member. The first extension portion extends continuously in the axial direction with a third outer diameter D3 and has a first raised portion with a fourth outer diameter D4 larger than the third outer diameter D3, which is joined to the first end member 4 at a first joint portion 6.

Description

Technical Field

[0001] The present invention relates to a metal fiber filter, a filter unit, and a vaporizer.

Background Art

[0002] Patent Document 1 below describes a filter element including a sintered fiber medium. This filter element includes a cylindrical body having an outer diameter that decreases from the central portion of the element toward one end portion of the element, and the fiber medium has a density that increases from the central portion of the element toward one end portion of the element. Such a filter element is expected to have an effect that welding at the end portion becomes easy because the end portion has a high density.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As shown in FIG. 5, a filter element a as described above may be housed in a housing b and used as a filter unit c. The housing b of the filter unit c has a fluid inlet d, an inlet flow path e for guiding the fluid that has entered from the inlet d to the outer peripheral surface of the filter element a, and an outlet f for taking out the fluid filtered by the filter element a.

[0005] In the filter unit c as described above, the fluid flowing through the inlet flow path e tends to stay near a portion a1 where the outer diameter is decreased provided at the axial end portion of the filter element a. Such retention of the fluid causes a decrease in filtration efficiency.

[0006] Further, for example, as shown in FIG. 6, even when the filter element a is disposed on one wall surface h in a large chamber, in the region a2 between the wall surface h and the portion where the outer diameter provided at the axial end of the filter element a is reduced, the fluid tends to stagnate.

[0007] The present invention has been devised in view of the above problems, and the main object thereof is to provide a metal fiber filter or the like that can suppress the stagnation of fluid at the end of a filter medium (filter element).

Means for Solving the Problems

[0008] The present invention is a metal fiber filter, a support body having a cylindrical shape defining an axial direction and a radial direction and having a first end, a filter medium disposed outside the support body in the radial direction, and a first end member fixed to the side of the first end of the support body, the support body includes a first support portion having a first outer diameter and a second support portion having a second outer diameter larger than the first outer diameter on the side of the first end of the first support portion, a plurality of through holes are formed in the first support portion, the second support portion is connected to the first support portion and forms the first end, the filter medium is a sintered body of metal fibers, the filter medium includes a media body disposed outside the first support portion in the radial direction and for filtering fluid, and a first extension portion disposed outside the second support portion in the radial direction and joined to the first end member, the media body and the first extension portion continuously extend axially with a third outer diameter, the first extension portion is joined to the first end member via a first joint portion, the first joint portion includes a first raised portion having a fourth outer diameter larger than the third outer diameter, which is a metal fiber filter.

[0009] In the present invention, the first raised portion may be formed by a welding bead.

[0010] In the present invention, the wall thickness of the first extension portion may be in the range of 5% to 40% of the wall thickness of the media body.

[0011] In the present invention, the wall thickness of the media body may be 4.0 mm or more.

[0012] In the present invention, the first end member may have a fifth outer diameter that is equal to or greater than the third outer diameter.

[0013] In the present invention, it is desirable that the second support portion is not provided with a through hole that penetrates in the radial direction.

[0014] In the present invention, the fourth outer diameter may be 1.0 mm or more larger than the third outer diameter.

[0015] In the present invention, the porosity of the first extension portion may be smaller than the porosity of the media body.

[0016] In the present invention, the porosity of the first extension portion may be 70% or less, and the porosity of the media body may be 80% or more.

[0017] In the present invention, the first end member may be an end cap that closes the side of the first end of the support body.

[0018] In the present invention, the support body has a second end on the side opposite to the first end, the support body includes a third support portion having a sixth outer diameter larger than the first outer diameter on the side of the second end of the first support portion, the third support portion is connected to the first support portion and forms the second end, a second end member is fixed to the side of the second end of the support body, The filter medium is arranged on the outer side in the radial direction of the third support portion and includes a second extension portion joined to the second end member. The media body and the second extension portion extend continuously in the axial direction with the third outer diameter. The side of the second end of the second extension portion is joined to the second end member via a second joint portion. The second joint portion can include a second raised portion having a seventh outer diameter larger than the third outer diameter.

[0019] In the present invention, the second raised portion may be formed by a welding bead.

[0020] In the present invention, the wall thickness of the second extension portion may be in the range of 5% to 40% of the wall thickness of the media body.

[0021] In the present invention, the first end member is an end cap that closes the side of the first end of the support. The second end member is a housing mounting member for fixing the side of the second end of the support to the housing. The second end member may have an opening for taking out the fluid in the space inside the support in the radial direction.

[0022] The present invention includes any one of the above metal fiber filters and a housing capable of accommodating the metal fiber filter. The housing is an inlet of the fluid, an inlet flow path for guiding the fluid entering from the inlet to the outer peripheral surface of the filter medium, and a filter unit having an outlet for taking out the fluid filtered by the filter medium and passing through the through hole of the first support portion and the opening of the second end member.

[0023] The present invention may be a vaporizer using the metal fiber filter described in any of the above.

Advantages of the Invention

[0024] The metal fiber filter of the present invention can reduce the risk of retention of the filtered fluid at the end of the filter medium and improve the filtration efficiency.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be understood that the drawings include representations that are different from the dimensional ratios of the actual structure in order to assist in understanding the present invention. Also, when there are multiple embodiments, the same reference numerals are assigned to the same or common elements throughout the specification, and duplicate descriptions are omitted. Furthermore, the specific configurations shown in the embodiments and the drawings are for the purpose of understanding the content of the present invention, and the present invention is not limited to the specific configurations shown.

[0027] [Metal Fiber Filter] FIG. 1 is a cross-sectional view of the metal fiber filter 1 of the present embodiment. As shown in FIG. 1, the metal fiber filter 1 of the present embodiment includes a support 2, a filter medium 3 disposed on the outer side in the radial direction of the support 2, and a first end member 4 disposed on one end side in the axial direction of the support 2. Further, the metal fiber filter 1 of the present embodiment is shown to include a second end member 5 disposed on the other end side in the axial direction of the support 2.

[0028] The metal fiber filter 1 of the present embodiment is used to capture foreign matters such as fine particles in a fluid. In particular, the metal fiber filter 1 of the present embodiment is used as a high-performance filter that captures foreign matters with high filtration efficiency from the fluid used in the manufacturing process of industrial products (for example, semiconductors, etc.) manufactured in an extremely clean environment. However, the fluid to be filtered by the metal fiber filter 1 of the present invention is not limited to a specific one.

[0029] [Support] The support 2 is configured in a cylindrical shape that defines an axial direction and a radial direction that is orthogonal thereto. In the cross-section orthogonal to the axial direction of the support 2, the direction along its outer surface is defined as the circumferential direction. The support 2 extends from the first end E1 to the second end E2 in the axial direction. The inside of the support 2 in the radial direction is a space i. The support 2 of the present embodiment is in a cylindrical shape with a circular cross-section. In other embodiments, the support 2 may be in a cylindrical shape with a polygonal cross-section.

[0030] The support 2 is formed of a metal material. The metal material is not particularly limited, but for example, stainless steel is adopted, and particularly, austenitic stainless steel excellent in workability and corrosion resistance is preferable. The support 2 of the present embodiment is preferably formed of SUS316L, which is more excellent in corrosion resistance.

[0031] Figure 2 shows an enlarged view of part II of Figure 1. As shown in Figures 1 and 2, the support 2 includes a first support portion 11 and a second support portion 12 provided on the side of the first end E1 of the first support portion 11. In the present embodiment, the first support portion 11 has an axially sufficient length compared to the second support portion 12.

[0032] [First support portion] The first support portion 11 is formed in a cylindrical shape having a first outer diameter D1. The first support portion 11 of the present embodiment extends continuously in the axial direction at the first outer diameter D1.

[0033] A plurality of through holes 11a are formed in the first support portion 11. Therefore, the fluid on the radially outer side of the first support portion 11 can flow into the internal space i of the first support portion 11 through the through holes 11a. The first support portion 11 of the present embodiment may be formed, for example, by processing a metal plate having holes formed at regular pitches such as perforated metal into a cylindrical shape. The aperture diameter and hole shape of the through holes 11a are not particularly limited and are appropriately set according to the application. In the present embodiment, the through holes 11a are circular with a diameter of 1.5 mm, and these are arranged at substantially equal intervals in the axial direction and the circumferential direction.

[0034] [Second support portion] The second support portion 12 has a second outer diameter D2 larger than the first outer diameter D1. That is, the second support portion 12 protrudes radially outward from the outer surface of the first support portion 11. The second support portion 12 of the present embodiment is formed in an annular shape and includes, for example, a radially outer peripheral surface 121, a radially inner peripheral surface 122, an axially inner end surface 123, and an axially outer end surface 124. In the present specification, with respect to the axial direction, "inner" and "outer" indicate relative directions in the axial direction, and the direction toward the axial end is defined as "outer", and the direction toward the axial center is defined as "inner".

[0035] The outer peripheral surface 121 of the second support portion 12 extends continuously in the axial direction, for example, at the second outer diameter D2.

[0036] In this embodiment, for example, the end of the first support portion 11 is fixed to the inner peripheral surface 122 of the second support portion 12. More specifically, the inner peripheral surface 122 is formed as a stepped surface including a concave portion 122a that extends in the axial direction with a constant inner diameter, and a convex portion 122b that is located on the side of the first end E1 of the concave portion 122a and protrudes radially inward from the concave portion 122a. The end of the first support portion 11 is disposed in the concave portion 122a, and the axial outer end surface of the first support portion 11 abuts against the stepped surface of the convex portion 122b. Further, the first support portion 11 and the second support portion 12 are fixed by welding or the like. In this embodiment, the inner peripheral surface of the first support portion 11 and the inner peripheral surface of the convex portion 122b of the second support portion 12 are formed to be axially continuous.

[0037] In this embodiment, for example, the axial inner end surface 123 of the second support portion 12 is formed as a tapered surface whose outer diameter gradually decreases toward the inside in the axial direction.

[0038] In this embodiment, for example, the axial outer end surface 124 of the second support portion 12 is formed as a plane orthogonal to the axial direction, and this plane forms the first end E1 of the support 2.

[0039] A solid single-piece material having no through hole extending in the radial direction is used for the second support portion 12 of this embodiment. Therefore, the fluid cannot pass through the second support portion 12.

[0040] [Filter medium] The filter medium 3 is fixed to the radial outer peripheral surface of the support 2. Therefore, the filter medium 3 of this embodiment has a cylindrical shape corresponding to the cylindrical shape of the support 2. In this embodiment, the filter medium 3 is fixed to the radial outer peripheral surface of the support 2 during sintering. However, the fixing method of the filter medium 3 and the support 2 is not particularly limited.

[0041] The filter medium 3 is composed of a sintered body of metal fibers. The metal fibers constituting the filter medium 3 are not particularly limited, and for example, stainless steel, especially austenitic stainless steel excellent in corrosion resistance (e.g., SUS316L, etc.), nickel alloy, pure nickel, etc. are appropriately used. The wire diameter of the metal fibers used for the filter medium 3 is also not particularly limited, but for example, in order to enhance the filtration efficiency, short fibers of about 0.5 to 10 μm are desirable. Such metal fibers are arranged on the outer peripheral surface of the support 2 and then put into a mold or the like to receive heat and pressure from the outside. Thereby, the aggregate of metal fibers is integrally formed on the outer peripheral surface of the support 2 as a cylindrical sintered body. Such a filter medium 3 has a porous structure in which fine voids through which the fluid passes are formed inside, and thus has a function as a filtration member having a high filtration accuracy.

[0042] The filter medium 3 includes a media body 30 and a first extension portion 31 formed on the side of the first end E1 of the media body 30. Further, the filter medium 3 of the present embodiment includes a second extension portion 32 formed on the side of the second end E2 of the media body 30.

[0043] The media body 30 is a portion of the filter medium 3 that is arranged radially outside the first support portion 11. The media body 30 is a portion that exhibits a filtration function as the original function of the filter medium 3. The media body 30 of the present embodiment has a cylindrical shape extending in the axial direction corresponding to the shape of the support 2. The first extension portion 31 is a portion of the filter medium 3 that is arranged radially outside the second support portion 12. The first extension portion 31 is integrated with the media body 30. The first extension portion 31 is used for joining with a first end member 4 described later.

[0044] In FIG. 2, in the present embodiment, the media body 30 and the first extension portion 31 extend continuously in the axial direction with a third outer diameter D3. That is, the media body 30 and the first extension portion 31 are continuous with the same outer diameter in the axial direction without a substantial step. However, since the filter media 3 is a sintered body of metal fibers, microscopically observed, there are minute irregularities on the surface of the filter media 3. Therefore, the term "without a substantial step" described above means allowing the existence of such minute irregularities on the surface that are inevitable as a sintered body of metal fibers. More specifically, the term "without a substantial step" described above should be understood as sufficient for those skilled in the art to recognize that the media body 30 and the first extension portion 31 are continuous with the same outer diameter in the axial direction when observed with the naked eye (macroscopic observation) under normal attention. In the case of microscopic observation, the difference between the maximum diameter and the minimum diameter of the filter media 3 can be, for example, 2 mm or less, preferably 1.5 mm or less, to more effectively suppress the retention of fluid.

[0045] [First End Member] The first end member 4 is fixed to the side of the first end E1 of the support 2. The first end member 4 of the present embodiment is configured, for example, as an end cap that closes the side of the first end E1 of the cylindrical support 2. The first end member 4 has a plate shape formed of a metal material, particularly austenitic stainless steel (SUS316L in the present embodiment) having excellent corrosion resistance. The first end member 4 includes an axially inner end face that abuts against the axially outer end face 124 of the second support portion 12. By the first end member 4, the fluid in the space i of the support 2 cannot flow out to the outside from the side of the first end E1 of the support 2.

[0046] Further, the first extension portion 31 is joined to the first end member 4 via the first joint portion 6. The first joint portion 6 of the present embodiment also joins the first end member 4 and the second support portion 12 of the support 2, but the first joint portion 6 only needs to join at least the first extension portion 31 and the first end member 4. Furthermore, the first joint portion 6 includes a first raised portion 6A having a fourth outer diameter D4 larger than the third outer diameter D3.

[0047] [Operation of the present embodiment] In the filter medium 3 of the present embodiment, the medium body 30 and the first extension portion 31 extend continuously in the axial direction with the third outer diameter D3. That is, the radially outer surfaces of the medium body 30 and the first extension portion 31 are formed of a continuous surface having substantially no recesses except for microscopic irregularities of the medium. Further, the first joint portion 6 includes a first raised portion 6A having a fourth outer diameter D4 larger than the third outer diameter D3. Therefore, the metal fiber filter 1 of the present embodiment can suppress the retention of the fluid to be filtered on the side of the first end E1. Further, the first raised portion 6A having a relatively large outer diameter (the fourth outer diameter D4) can also guide the fluid, for example, to the side of the medium body 30 having a small outer diameter. From the above, the metal fiber filter 1 of the present embodiment helps to reduce the pressure loss of the fluid to be filtered and generate a uniform flow velocity, and also has excellent filtration efficiency.

[0048] Hereinafter, more preferable embodiments of the present invention will be described, but the following are all optional components of the present invention.

[0049] The first joint portion 6 may be formed by various joining means. The first joint portion 6 may be generated, for example, by welding, brazing, diffusion bonding, or friction pressure welding. From the viewpoint of preventing leakage (short path) of fluid from the first joint portion 6, welding is particularly desirable as the joining means because an airtight joint portion can be easily obtained, and in particular, TIG welding or the like is desirable. The first joint portion 6 of the present embodiment is a circumferentially continuous weld bead formed by welding, and the first raised portion 6A is also formed at a portion where this weld bead bulges outward in the radial direction.

[0050] The radially protruding amount of the first raised portion 6A from the outer surface of the filter medium 3 (that is, (D4 - D3) / 2) is not particularly limited, but from the viewpoint of improving the joining strength and expecting the action of guiding the fluid to the side of the medium body 30, it is preferably 0.5 mm or more, and more preferably 0.9 mm or more. That is, it is desirable that the fourth outer diameter D4 is 1.0 mm or more larger than the third outer diameter D3.

[0051] In this embodiment, the first extension portion 31 of the filter medium 3 has a wall thickness t1 smaller than that of the medium body 30. Further, since the first extension portion 31 has a porous structure made of a sintered body of metal fibers, it is likely to be deformed by heat during welding. However, since the first extension portion 31 of this embodiment is supported from the inner side in the radial direction by the second support portion 12, while suppressing melting and pore formation during welding, it is possible to join with the support 2 and the first end member 4. Further, since the filter medium 3 has an integral structure joined to the support 2 and the first end member 4, it has high rigidity and can exhibit excellent strength, for example, even in a vibrating environment or under high pressure.

[0052] The outer diameter of the first end member 4 (hereinafter referred to as "the fifth outer diameter D5") is not particularly limited, but in this embodiment, it is set to be equal to or greater than the third outer diameter D3 of the filter medium 3. Therefore, fluid retention can also be suppressed around the first end member 4.

[0053] The wall thickness t0 of the medium body 30 is not particularly limited, but in order to further improve the filtration accuracy, for example, it may be 3.0 mm or more, preferably 3.5 mm or more.

[0054] The wall thickness t1 of the first extension portion 31 is not particularly limited either, but for example, it may be 5% or more, preferably 10% or more, more preferably 15% or more of the wall thickness t0 of the medium body 30. By setting the wall thickness t1 of the first extension portion 31 to be 5% or more of the wall thickness t0 of the medium body 30, for example, when welding and joining the first extension portion 31 and the first end member 4, melting and the like of the first extension portion 31 can be more reliably suppressed, and ultimately, an airtight first joint portion 6 can be formed. This helps to effectively suppress a fluid short circuit in the vicinity of the first joint portion 6.

[0055] On the other hand, if the wall thickness t1 of the first extension portion 31 becomes excessively large, it may be difficult to form the deep first joint portion 6 that reaches the second support portion 12. From such a viewpoint, the wall thickness t1 of the first extension portion 31 may be, for example, 40% or less, preferably 35% or less, and more preferably 30% or less of the wall thickness t0 of the media body 30.

[0056] From the above viewpoints, as one aspect, when the wall thickness t0 of the media body 30 is 5.0 mm, the wall thickness t1 of the first extension portion 31 is desirably in the range of, for example, 0.25 to 2.0 mm, preferably 0.50 to 1.75 m, and more preferably 0.75 to 1.5 mm.

[0057] The porosity of the first extension portion 31 is desirably smaller than the porosity of the media body 30. Thereby, the rigidity of the first extension portion 31 joined to the first end member 4 is relatively increased, and joining defects during welding and the like are suppressed. In a preferred embodiment, the porosity of the first extension portion 31 may be, for example, 70% or less, preferably 65% or less, and more preferably 60% or less. Such a porosity of the first extension portion 31 can be obtained, for example, by adjusting the degree of compression acting on the first extension portion 31 to be higher than that of the media body 30 during the sintering process. Further, the first extension portion 31 is desirably a porous structure body mainly including pores having a pore diameter of 2 to 6 μm.

[0058] In this specification, the "porosity" of the porous structure is represented by the ratio of the volume of the void portion to the apparent total volume of the target region. In this specification, the porosity is obtained by calculation. In that case, first, the mass of the filter media is measured, and the volume including the voids of the filter media is obtained. Next, the mass of the solid material having the same volume as the volume of the filter media is measured. And the porosity can be calculated from the following formula (1). Porosity (%) = {1 - (mass of filter media / mass of solid material)} * 100 …(1)

[0059] Since the media body 30 is supported from the inner side in the radial direction by the first support portion 11, it is possible to ensure a high differential pressure resistance strength against the fluid pressure during filtration. Therefore, even if the velocity of the fluid is increased, deformation of the filter medium 3 and the like are suppressed, and as a result, it contributes to an improvement in filtration efficiency. In order to sufficiently exhibit a suitable filtration function, the porosity of the media body 30 may be made larger than the porosity of the first extension portion 31. In a preferred embodiment, the porosity of the media body 30 may be, for example, 80% or more, preferably 85% or more, and more preferably 90% or more. Similarly, the media body 30 may be a porous structure mainly including a pore diameter larger than that of the first extension portion 31. In a preferred embodiment, it is desirable that the media body 30 be a porous structure mainly including a pore diameter of 5 to 30 μm, in particular.

[0060] [Third support portion] The support 2 of the present embodiment further includes a third support portion 13 having a sixth outer diameter D6 larger than the first outer diameter D1 on the side of the second end E2 of the first support portion 11. That is, the third support portion 13 protrudes radially outward from the outer surface of the first support portion 11. The outer peripheral surface 131 of the third support portion 13 extends continuously in the axial direction, for example, with the sixth outer diameter D6. In this embodiment, the sixth outer diameter D6 is the same as the second outer diameter D2 of the second support portion 12, but it may be different.

[0061] Since the configuration of the third support portion 13 has the same configuration as that of the second support portion 12, the description thereof is omitted. That is, the radially outer peripheral surface 131, the radially inner peripheral surface 132, the axially inner end surface 133, and the axially outer end surface 134 of the third support portion 13 each have the same configuration as the radially outer peripheral surface 121, the radially inner peripheral surface 122, the axially inner end surface 123, and the axially outer end surface 124 of the second support portion 12. Further, an end portion on the side of the second end E2 of the first support portion 11 is fixed to the inner peripheral surface 132 of the third support portion 13.

[0062] [Second end member] On the side of the second end E2 of the support 2, a second end member 5 is fixed. In the present embodiment, the second end member 5 is a housing mounting member for fixing the side of the second end E2 of the support 2 to a housing (described later). More specifically, the second end member 5 has a disk shape with an opening 5a formed at the center. The second end member 5 is fixed to the side of the second end E2 of the support 2 with its center aligned with the axis of the support 2. The outer diameter of the second end member 5 has the largest eighth outer diameter D8 in the metal fiber filter 1, and its outer peripheral portion is fixed to the housing described later. Further, the opening 5a of the second end member 5 is used to take out the fluid in the space i inside the support 2 in the radial direction.

[0063] [Second extension part] The filter medium 3 of the present embodiment includes a second extension part 32 arranged on the outside in the radial direction of the third support part 13 and joined to the second end member 5. The second extension part 32 is integrated with the media body 30. The second extension part 32 is used for joining with the second end member 5 described later.

[0064] In the present embodiment, the media body 30 and the second extension part 32 extend continuously in the axial direction with a third outer diameter D3. That is, the media body 30 and the second extension part 32 are continuous with the same outer diameter in the axial direction without a substantial step. As described above, the term "without a substantial step" should be understood as sufficient for those skilled in the art to recognize that when observing the connection part between the media body 30 and the second extension part 32 with the naked eye (macroscopic observation), they are continuous with the same outer diameter in the axial direction.

[0065] Further, the second extension part 32 is joined to the second end member 5 via a second joint part 7. The second joint part 7 of the present embodiment also joins between the second end member 5 and the third support part 13 of the support 2, but the second joint part 7 only needs to join at least the second extension part 32 and the second end member 5. Further, the second joint part 7 includes a second raised part 7A having a seventh outer diameter D7 larger than the third outer diameter D3.

[0066] In such an embodiment, the media body 30 and the second extension portion 32 extend axially continuously with a third outer diameter D3. That is, the radially outer surfaces of the media body 30 and the second extension portion 32 are formed as continuous surfaces having no substantial recesses except for microscopic irregularities of the media. Therefore, in the metal fiber filter 1 of the present embodiment, the section between the first joint portion 6 and the second joint portion 7 of the filter media 3 is substantially axially continuous with the third outer diameter D3. Therefore, the metal fiber filter 1 of the present embodiment can also suppress the retention of the fluid to be filtered on the side of the second end E2 of the filter media 3. Further, the second raised portion 7A having a relatively large outer diameter (seventh outer diameter D7) can also guide the fluid, for example, to the side of the media body 30 having a small outer diameter.

[0067] The second joint portion 7 may be formed by various joining means. For example, the second joint portion 7 may be formed by welding, brazing, diffusion bonding, or friction pressure welding. From the viewpoint of preventing leakage (short circuit) of fluid from the second joint portion 7, welding, which can easily obtain an airtight joint portion, is particularly desirable as the joining means, and in particular, TIG welding or the like is desirable. The second joint portion 7 of the present embodiment is also a circumferentially continuous weld bead formed by welding, and the second raised portion 7A is also formed by a portion where this weld bead bulges outward in the radial direction.

[0068] The radially protruding amount of the second raised portion 7A from the outer surface of the filter media 3 (that is, (D7 - D3) / 2) is not particularly limited, but from the viewpoint of expecting an improvement in joining strength and an action of guiding the fluid to the side of the media body 30, it may be preferably 0.5 mm or more, more preferably 0.9 mm or more. That is, it is desirable that the seventh outer diameter D7 is 1.0 mm or more larger than the third outer diameter D3.

[0069] In the present embodiment, the second extension portion 32 of the filter medium 3 has a wall thickness t2 that is smaller than that of the medium main body 30. Further, since the second extension portion 32 has a porous structure made of a sintered body of metal fibers, it is likely to be deformed or the like due to the heat during welding. However, since the second extension portion 32 of the present embodiment is supported from the inner side in the radial direction by the third support portion 13, while suppressing melting and falling or the formation of pores during welding, it is possible to join with the support 2 and the second end member 5, and it is possible to suppress a short path of fluid or the like. Further, since the filter medium 3 has an integrated structure joined to the support 2 and the second end member 5, it has high rigidity, and for example, it can exhibit excellent strength even in an environment where it vibrates or under high pressure.

[0070] The wall thickness t2 of the second extension portion 32 is not particularly limited, but for example, it is preferably in the same range as the wall thickness t1 of the first extension portion 31. That is, the wall thickness t2 of the second extension portion 32 may be 5% or more, preferably 10% or more, and more preferably 15% or more of the wall thickness t0 of the medium main body 30.

[0071] On the other hand, if the wall thickness t2 of the second extension portion 32 becomes excessively large, there is a risk that it may be difficult to form a deep second joint portion 7 reaching the third support portion 13. From such a viewpoint, the wall thickness t2 of the second extension portion 32 may also be, for example, 40% or less, preferably 35% or less, and more preferably 30% or less of the wall thickness t0 of the medium main body 30.

[0072] From the above viewpoints, as one aspect, when the wall thickness t0 of the medium main body 30 is 5.0 mm, the wall thickness t2 of the second extension portion 32 is also, for example, preferably in the range of 0.25 to 2.0 mm, more preferably in the range of 0.50 to 1.75 m, and even more preferably in the range of 0.75 to 1.5 mm.

[0073] The porosity of the second extension portion 32 is preferably smaller than the porosity of the media body 30. Thereby, the rigidity of the second extension portion 32 joined to the second end member 5 is relatively increased, and joining defects during welding and the like are suppressed. In a preferred embodiment, the porosity of the second extension portion 32 may be, for example, 70% or less, preferably 65% or less, and more preferably 60% or less. Further, the second extension portion 32 is preferably a porous structure mainly including pore diameters of, for example, 2 to 6 μm.

[0074] [Housing] FIG. 4 is a cross-sectional view of a filter unit 100 using the metal fiber filter 1 of the present embodiment. As shown in FIG. 4, the filter unit 100 includes a housing 101 having a space capable of accommodating the metal fiber filter 1. The housing 101 has a fluid inlet 102, an inlet flow path 103 for guiding the fluid entering from the inlet 102 to the outer peripheral surface of the filter medium 3, and an outlet 104 for the fluid filtered by the filter medium 3.

[0075] The housing 101 is made of, for example, stainless steel, and is preferably formed of austenitic stainless steel. The housing 101 of the present embodiment is particularly composed of SUS316L having excellent corrosion resistance. The housing 101 forms an exterior body of the metal fiber filter 1, for example, when implemented as an in-line filter.

[0076] In the filter unit 100 of FIG. 4, the fluid to be filtered entering from the inlet 102 circulates through the inlet flow path 103 between the housing 101 and the metal fiber filter 1 to the outer peripheral surface side of the filter medium 3. When the fluid that has circulated to the outer peripheral surface side of the filter medium 3 passes through the filter medium 3, foreign matters such as fine particles are captured by the filter medium 3 and purified. Further, the purified fluid is taken out from the outlet 104 through the through-hole 11a of the first support portion 11, the space i inside the support 2, and the opening 5a of the second end member 5.

[0077] In the above-described filtration process, as described above, the outer surfaces of the media body 30, the first extension portion 31, and the second extension portion 32 of the filter medium 3 are axially continuous with substantially the same third outer diameter D3. Further, the first joint portion 6 and the second joint portion 7 located at both axial ends of the filter medium 3 are provided with a first raised portion 6A and a second raised portion 7A having an outer diameter larger than the third outer diameter D3, respectively. Therefore, the fluid easily flows from the first raised portion 6A and the second raised portion 7A toward the media body 30 side, and the retention on both axial sides of the media body 30 is suppressed. As a result, a reduction in pressure loss and a uniform flow velocity during the filtration process can be generated.

[0078] Further, since the filter medium 3 is supported from the radially inner side by the support 2, even if it is a porous structure, the differential pressure resistance strength during filtration can be maintained high. Therefore, the metal fiber filter 1 and the filter unit 100 of the present embodiment can be suitably used even in a high filtration pressure environment, and in this respect, it is also possible to contribute to an improvement in filtration efficiency.

[0079] Since the metal fiber filter 1 of the present embodiment can reduce the pressure loss associated with filtration, for example, even when filtering a low vapor pressure liquid, re-liquefaction inside the filter medium 3 can be prevented. Therefore, the metal fiber filter 1 of the present embodiment can also be utilized as a vaporizer. For example, in a semiconductor manufacturing process, when filtering a low vapor pressure liquid, which is a fluid obtained by vaporizing a precursor, re-liquefaction inside the filter medium 3 can be prevented.

[0080] The metal fiber filter 1 of the present invention may be used without using the housing 101. For example, as shown in FIG. 6, when it is implemented as a diffuser (vent filter) mounted in a vacuum chamber, such as directly flowing the gas immediately after filtration to the next process, the housing 101 becomes unnecessary.

[0081] As described above in detail are the embodiments of the present invention. However, the present invention is not limited to the above specific disclosure, and various modifications can be made and implemented within the scope of the technical idea described in the claims.

Explanation of Reference Numerals

[0082] 1 Metal fiber filter 2 Support 3 Filter medium 4 First end member 5 Second end member 5a Opening 6 First joint 6A First ridge 7 Second joint 7A Second ridge 11 First support 11a Through hole 12 Second support 13 Third support 30 Media body 31 First extension 32 Second extension 100 Filter unit 101 Housing 102 Inlet 103 Inlet flow path 104 Outlet E1 First end E2 Second end

Claims

1. A metal fiber filter, comprising: a support body having a cylindrical shape defining an axial direction and a radial direction, and having a first end; a filter medium disposed outside the support body in the radial direction; a first end member fixed to the side of the first end of the support body; the support body includes a first support portion having a first outer diameter, and a second support portion disposed on the side of the first end of the first support portion and having a second outer diameter larger than the first outer diameter; a plurality of through holes are formed in the first support portion; the second support portion is connected to the first support portion and forms the first end; the filter medium is a sintered body of metal fibers; the filter medium includes a media body disposed outside the first support portion in the radial direction and for filtering fluid, and a first extension portion disposed outside the second support portion in the radial direction and joined to the first end member; the media body and the first extension portion extend continuously in the axial direction with a third outer diameter; the first extension portion is joined to the first end member via a first joint portion; the first joint portion includes a first raised portion having a fourth outer diameter larger than the third outer diameter; A metal fiber filter.

2. The metal fiber filter according to claim 1, wherein the first raised portion is formed by a welding bead.

3. The metal fiber filter according to claim 1, wherein the wall thickness of the first extension portion is in the range of 5% to 40% of the wall thickness of the media body.

4. The metal fiber filter according to claim 3, wherein the wall thickness of the media body is 4.0 mm or more.

5. The metal fiber filter according to claim 1, wherein the first end member has a fifth outer diameter equal to or larger than the third outer diameter.

6. The metal fiber filter according to claim 1, wherein the second support portion is not provided with a through hole penetrating in the radial direction.

7. The metal fiber filter according to claim 1, wherein the fourth outer diameter is 1.0 mm or more larger than the third outer diameter.

8. The metal fiber filter according to claim 1, wherein the porosity of the first extension portion is smaller than the porosity of the media body.

9. The metal fiber filter according to claim 1, wherein the porosity of the first extension portion is 70% or less, and the porosity of the media body is 80% or more.

10. The metal fiber filter according to claim 1, wherein the first end member is an end cap that closes the side of the first end of the support body.

11. The support has a second end opposite to the first end, The support includes a third support portion having a sixth outer diameter larger than the first outer diameter on the side of the second end of the first support portion, The third support portion is connected to the first support portion and forms the second end, A second end member is fixed to the side of the second end of the support, The filter medium includes a second extension portion disposed on the outer side in the radial direction of the third support portion and joined to the second end member, The media body and the second extension portion extend continuously in the axial direction with the third outer diameter, The side of the second end of the second extension portion is joined to the second end member via a second joint portion, The metal fiber filter according to claim 1, wherein the second joint portion includes a second raised portion having a seventh outer diameter larger than the third outer diameter.

12. The metal fiber filter according to claim 11, wherein the second raised portion is formed by a welding bead.

13. The metal fiber filter according to claim 11, wherein the wall thickness of the second extension portion is in the range of 5% to 40% of the wall thickness of the media body.

14. The first end member is an end cap that closes the side of the first end of the support, The second end member is a housing mounting member for fixing the side of the second end of the support to the housing, The metal fiber filter according to claim 11, wherein the second end member has an opening for taking out the fluid in the space inside the support in the radial direction.

15. A metal fiber filter according to claim 14, and a housing capable of accommodating the metal fiber filter, The housing includes an inlet for the fluid, an inlet flow path for guiding the fluid entering from the inlet to the outer peripheral surface of the filter medium, and an outlet for taking out the fluid filtered by the filter medium and passing through the through hole of the first support portion and the opening of the second end member. A filter unit.

16. A vaporizer using the metal fiber filter according to any one of claims 1 to 14.

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