JP2004074086A - Filter assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter assembly preferably usable for microfiltration to be employed for filtration of semiconductor fabrication gases. <P>SOLUTION: The filter assembly is provided with a base member having a leading inlet and a leading outlet of an object fluid, a filter member fixed in the base member and filtering the object fluid during the time the object fluid flows from the leading inlet to the leading outlet, and a cup-like housing member to be heat-joined to the base member while surrounding the filter member. The filter assembly is characterized in that the filter member is strongly pressurized to the filter installation face of the base member because of thermal shrinkage accompanying the cooling at the time of thermal bonding of the housing member and the base member. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filter assembly that can be suitably used for microfiltration that can be used for filtering semiconductor manufacturing gas and the like.
[0002]
[Prior art]
The filter device has an inlet through which the fluid to be treated flows in, and an outlet through which the fluid to flow out, and has a filter member for filtering the fluid to be treated disposed therein and is entirely surrounded by a housing member. Specific specifications such as the optimum shape, size, and structure are determined according to the type, characteristics, filter medium conditions, installation space, and the like of the processing fluid.
[0003]
For example, in a filtration device that requires ultra-high purity filtration, such as for a semiconductor production gas, the filter member has an accuracy of, for example, 10 to 10 fine particles having a size of 0.01 μm or more per unit volume (1 cf). Therefore, when a filter member is assembled, it is essential that leakage does not occur from the mounting portion and that the filter member is reliably and excellent in productivity.
[0004]
For this reason, the present inventor has proposed a method of attaching a filter member, for example, a method of mechanically pressing and sealing a sheet-like filter medium by pressing between mounting surfaces in a housing, a method of Japanese Patent No. 2813274, a brazing method, a diffusion welding method, and the like. A method of directly heating both, such as a legal method, is proposed in Japanese Patent No. 3215501, and a method in Japanese Patent Application Laid-Open No. 8-132226 is proposed.
[0005]
On the other hand, for example, in the semiconductor manufacturing process, a piping circuit is also complicated, and various types of components and components such as valves and filters are connected to various pipings. In recent years, a so-called integrated panel type, which is a single panel in which other necessary components and components including a filter assembly are previously piped and incorporated as a unit, has been frequently used in order to reduce the number of components.
[0006]
According to this method, it is possible to form a unit in which various devices and parts necessary for piping such as a filter assembly are arranged neatly in advance on a panel base, and it is also easy to replace members. The filter assembly used to constitute such a unit body is different from the case where it is interposed in a pipe, for example, as shown in FIG. 6, an inlet a into which a fluid to be treated flows, The outlet b from which the filtered fluid flows out is opened together with one surface of a base member c in the form of a rectangular block, for example, to facilitate assembly as a panel.
[0007]
In this filter assembly, the filter member d for filtering the fluid to be treated from the inlet port a is formed by a brazing method or a diffusion bonding method proposed in, for example, the aforementioned Japanese Patent No. 3215501 and Japanese Patent Application Laid-Open No. 8-132226. For example, the housing member f that is directly welded to the base member c or fixed to the base member c via the ring body e and surrounds the filter member d has a gap with the entire peripheral surface of the filter member d. It has and is attached. The base member c is provided with through holes at four corners, for example, so that it can be fixed to the panel.
[0008]
[Problems to be solved by the invention]
By the way, when the filter member d is attached to the base member c by a brazing method, a diffusion bonding method, or the like, since both are directly heated, they are arranged in a heat treatment furnace and subjected to a bonding process. Is directly affected by heat, thereby causing deformation, deterioration of corrosion resistance, coloring, and the like. In addition, at a connection portion such as the inlet a of the base member c, required hardness cannot be maintained due to softening, which causes a decrease in function. There are issues such as. It has also been attempted to solve the problem by interposing the ring body e, brazing the ring body e and the filter member d, and then welding the base member c. It is necessary to perform two steps of a brazing process and a welding process, which increases the manufacturing cost. In addition, the use of the ring body e increases the number of parts, complicates inventory management, stagnates a processing fluid in a minute gap generated at a weld joint, and removes oxidizing impurities generated during welding. Post-processing is required, which tends to increase costs.
[0009]
Further, in the conventional structure, the welding of the filter member d to the base member c or the ring body e itself reduces the corrosion resistance due to the thermal influence on the porous filter member d, and causes pore closure due to the capillary action of the brazing material. There is a major problem in quality, such as a decrease in the effective filtration area. Further, the thermal expansion of the porous metal is larger than that of a normal metal material, and is likely to sometimes cause damage to the filter member d.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a high quality filter assembly which can be assembled efficiently and accurately.
[0011]
[Means for Solving the Problems]
The invention according to claim 1 of the present application is a filter assembly, wherein a base member provided with an inlet and an outlet for a fluid to be treated, and the fluid to be treated being fixed to the base member and flowing through the inlet is provided. A filter member that filters the fluid to be processed while flowing out of the outlet, and a cup-shaped housing member that surrounds the filter member and is coupled to the base member;
The filter member is strongly pressed against the filter mounting surface of the base member by heat shrinkage due to heat coupling between the housing member and the base member.
[0012]
The invention according to claim 2 is characterized in that the filter member is pressed directly or indirectly by the inward surface of the housing member, so that the filter member is strongly pressed against the filter mounting surface. The present invention is characterized in that a gasket member that is pressed and deformed by the strong pressure is interposed between the end surface of the filter member and the filter mounting surface.
[0013]
Further, the invention according to claim 4 is characterized in that the filter member is formed by a composite structure of a filter layer that cannot withstand a filtration pressure by itself and a support that supports the filter layer.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
1A is a longitudinal sectional view illustrating one embodiment of a filter assembly 1 according to the present invention, and FIG. 1B is a bottom view of the filter assembly 1. The filter assembly 1 has a block-shaped base member. 2, a filter member 4, and a housing member 6. In the present embodiment, a gasket 8 is disposed between the base member 2 and the filter member 4.
[0015]
In the present embodiment, the base member 2 is provided with a bulging portion 2c having a tapered surface increasing in diameter rearward via a central cylindrical portion 2b on the upper surface of the base 2a having a square bottom surface (a bottom surface is referred to as a bottom and the opposite side is referred to as an upper). The upper surface of the bulging portion 2c forms a ring-shaped filter mounting surface 2e inside the peripheral wall portion 2d having a small height on the outer peripheral edge. Although the filter mounting surface 2e is a flat surface in the present embodiment, it can also be formed in a tapered shape, and the cylindrical portion 2b has a stepped surface 2g1 notched around the upper end thereof and in contact with the end surface 6a1 of the housing member 6. And a step 2g for mounting the housing member 6 is formed.
[0016]
The base member 2 has an inlet 2A penetrating the bulging portion 2c at the center thereof, and a guide hole passing through the inside of the step 2g and opening at the rear surface of the cylindrical portion 2b. An outlet 2B is formed, and mounting holes 2h for mounting bolts are formed in four corners of the base 2a.
[0017]
The filter member 4 has a bottomed cup shape in which one end of a cylindrical portion 4a is closed by an upper plate portion 4b, and an open end surface 4c thereof is in contact with a filter mounting surface 2e in the peripheral wall portion 2d. As shown in FIG. 2, the member 4 has a laminated structure in which a filtration layer 4B having micropores is provided on the outer peripheral surface of a support 4A made of a relatively strong porous, for example, metal sintered body having a bottomed cup shape. I have a body. In addition, by forming a laminate in this manner, the support 4A can support the filtration layer 4B that cannot withstand the filtration pressure by itself, and when the entire filter has the same filtration accuracy as a single-layer filtration material. In comparison, the flow resistance can be significantly reduced, and the filtration characteristics as a whole can be improved.
[0018]
Further, in the present embodiment, the filter member 4 has a wave-shaped uneven portion 4d in which the outer peripheral surface alternates in the circumferential direction with peaks and valleys extending along the axial direction, thereby increasing the filtration area of the filtration layer 4B. In addition, the pressure resistance characteristics at the time of assembling the device are improved. Note that the uneven portion 4d may be formed in a projecting shape such as a hemisphere.
[0019]
The uneven portion 4d and the filtration layer 4B may be formed on one or both of the inner and outer peripheral surfaces of the support 4A. In particular, when provided only on the inner peripheral surface side, the effective diameter of the fine layer is reduced, so that the filtration area is reduced. On the other hand, the inward surface 6b1 of the bottom plate 6b of the housing member 6 pressing the filter member 4 is reduced. There is a support 4A having relatively coarse pores between them, and there is an advantage that the bottom plate 4b of the filter member 4 can also be used as a filtration surface.
[0020]
When the filter member 4 is for filtering semiconductor process gas, for example, the support 4A is made of a metal powder (for example, a metal atomized powder of about 10 to 100 μm) such as stainless steel, nickel, and a nickel alloy. For example, a thickness of 1.0 to 15 mm (preferably 1.0 to 5.5 mm, more preferably 1.0 to 2.0 mm) obtained by sintering a porous body having an outer diameter of about 10 to 30 mm and a length of about 10 to 100 mm. 5 mm) cup-shaped metal sintered body.
[0021]
By using the support 4A made of such a metal sintered body, sufficient strength capable of withstanding high pressure acting on the filtration layer 4B, relatively large pores (for example, 10 to 30 μm), and high porosity (30 to 30 μm) are obtained. 80%), and pore characteristics that do not affect the flow resistance of the fluid to be treated. Further, the uneven portion 4d has a width of about 2 to 10 mm and a height of about 1 to 10 mm, but the specifications such as dimensions may vary depending on the specific application and performance.
[0022]
Further, the filtration layer 4B is a portion that substantially guarantees filtration accuracy and has extremely fine pores than the support 4A. It exerts a characteristic capable of removing 10 to 10 ultrafine particles of about 0.01 μm (preferably 0.003 μm), or more precisely. For this reason, the powder can be formed using, for example, ultrafine metal particles, metal short fibers, or a mixed powder thereof, and has a thickness of, for example, about 0.1 to 1 mm (preferably 0.3 to 1 mm). .About.0.6 mm) and can be formed to be integral with the support 4A to resist the filtration pressure.
[0023]
In addition, as the metal particles, for example, a powdery material having a particle size of 5 μm or less, preferably about 3 to 0.05 μm, particularly, a corrosion-resistant stainless steel such as SUS316L, or the above-mentioned nickel or nickel alloy can be suitably used. Further, as short fibers, the aspect ratio is about 2 to 20, the fiber diameter is about 3 to 0.1 μm, and particularly when the aspect ratio is in the above range, the obtained pores become three-dimensional solid pores. In addition, it has large voids even though it is fine voids (Japanese Patent Publication No. 63-63645).
[0024]
Such a filter member 4 having a multilayer structure can be formed by, for example, a suction molding method for a support 4A disclosed in Japanese Patent No. 3177512, and a laminate on which a filtration layer is formed by such a method is subjected to temperature control. The filter member 2 is obtained by sintering in a sintering furnace at about 1050 ° C. The filter member 2 may have various shapes such as a rod shape, a conical shape, and a non-cylindrical shape other than the cup shape, and may be variously changed as necessary, such as a multilayer structure having an increased number of layers.
[0025]
The housing member 6 has a cup shape having a cylindrical portion 6a that fits into the step 2g of the base member 2 and an upper plate portion 6b that closes the rear end, and the end of the cylindrical portion 6a is the step 2g. And the end face 6a1 is attached in contact with the step surface 2g1, so that the cylindrical portion 6a surrounds the cylindrical portion 4a of the filter member 4 with a gap G, and as a result, A filtration channel can be formed that flows from the port 2A through the filtration layer 4B of the filter member 4 and flows out of the gap G through the outlet 2B. In addition, the filter assembly 1 can also flow in the fluid to be processed from the outlet 2B shown in the drawing and flow it out from the inlet 2A shown in the drawing.
[0026]
The housing member 6 is fitted into the step 2g of the base member 2 and the joint portion is heated and joined by heat welding such as welding, for example. 4 is strongly pinched between the inward surface 6b1 of the upper plate portion 6b of the housing member 6 and the filter mounting surface 2e of the base member 2, and comes into close contact with the outer filter mounting surface 2e. Leaks can be prevented.
[0027]
In this embodiment, a gasket member 8 that is deformed by pressing is interposed between the filter mounting surface 2e and the opening end surface 4c of the filter member 4 in order to more reliably prevent leakage. The gasket 8 may be, for example, a sintered porous body having pores finer than the filtration layer 4B, or a hollow disk-shaped one made of a soft metal material that is ductilely deformed by pressing. Further, as shown in FIG. 4, a cover layer 4C that extends the filtration layer 4B to the open end face 4c of the filter member 4 and covers the open end face 4c can be used as the gasket 8, as shown in FIG. Further, as shown in FIG. 5, the filter mounting surface 2e is inclined in a tapered shape, and when pressed, the filtration layer 4B in the inclined portion is reduced in diameter according to the taper, whereby the filtration layer 4B is formed. The dense portion to be densified can be used as the gasket 8.
[0028]
Further, as shown by a dashed line in FIGS. 1B and 2, a gas permeable member 10 such as a sintered body having a large hole is provided between the bottom plate 4 b of the filter member 4 and the bottom plate 6 b of the housing member 6. The gas permeable member 10 can be combined with the gasket member 8 so as to function as a cushioning material for reducing the pressure applied to the filter member 4.
[0029]
Further, as described above, the filter member 4 sets the filter member 4 on the filter mounting surface 2e of the base member 2 and utilizes heat shrinkage of the housing member 6 and the base member 2 after heat welding. The filter mounting surface 2e and the opening end surface 4c of the filter member 4 can be in direct contact with each other, or the gasket member 8 can be interposed.
[0030]
In addition, the housing member 6 can press the filter member 4 with an appropriate pressure that does not leak or damage according to the pressing length including the filter member 4, the gasket member 8, the gas permeable member 10, and the like that are used as necessary. As described above, the length L (the length between the end surface 6c of the housing member 6 and the inner surface of the upper plate portion 6b) is preset in consideration of the amount of heat shrinkage.
[0031]
In addition, the housing member 6 itself is positioned and mounted by the step 2g, so that the housing member 6 can be accurately coupled to the base member 2 to prevent eccentricity and deformation, and no gap is formed between the housing member 6 after the heat shrinkage. Structure. For this reason, when assembling the filter assembly 1, it is preferable to confirm the degree of pressing and the heat shrinkage rate by a preliminary test. Further, for example, when the filter assembly of the present invention is configured using stainless steel, titanium, or the like, it has excellent corrosion resistance and mechanical properties, and has a large coefficient of thermal expansion. The filter member 4 can be pressed accurately with a large force.
[0032]
【The invention's effect】
As described above, the filter assembly of the present invention can be in close contact with the base member without directly heating the filter member due to heat shrinkage caused by cooling when the housing member is fixed to the base member. Coloring and deterioration of corrosion resistance, as well as destruction and the like, can be suppressed.
Furthermore, since no heat treatment is applied to the porous filter member, it is possible to prevent clogging and deformation of the pores due to brazing material generated by brazing and the like, and to suppress a decrease in corrosion resistance, and to reduce the number of parts. Problems such as parts management and deterioration of workability can be reduced, and costs can be reduced.
[Brief description of the drawings]
FIG. 1A is a longitudinal sectional view of a filter assembly of the present invention, and FIG. 1B is a bottom view thereof.
FIG. 2 is a longitudinal sectional view illustrating a filter member.
FIG. 3 is a cross-sectional view in a plane orthogonal to FIG. 2;
FIG. 4 is a partial sectional view showing another example of the filter member.
FIG. 5 is a sectional view showing another example of the filter member.
FIG. 6A is a longitudinal sectional view illustrating a conventional filter assembly, and FIG. 6B is a bottom view thereof.
[Explanation of symbols]
2 Base member 2A Inlet 2B Outlet 2a Base 2b Column 2c Swell 2d Peripheral edge 2e Filter mounting surface 2g Step 2g1 Step surface 4 Filter member 4A Support 4B Filter layer 4a Tubular portion 4b Upper plate 4c Open end surface 6 Housing member 6a Tube portion 6b Upper plate portion 6b1 Inward surface 6c End surface L Length

Claims (4)

A base member provided with an inlet and an outlet for the fluid to be treated, a filter member fixed to the base member, and filtering the fluid to be treated while the fluid to be treated from the inlet flows out of the outlet; And a cup-shaped housing member surrounding the filter member and coupled to the base member,
The filter assembly is characterized in that the filter member is strongly pressed against the filter mounting surface of the base member by heat shrinkage accompanying cooling when the housing member and the base member are heated and coupled. The filter assembly according to claim 1, wherein the filter member is pressed against the filter mounting surface by being directly or indirectly pressed by an inward surface of the housing member. 3. The filter assembly according to claim 2, wherein a gasket member that is pressed and deformed by the strong pressure is interposed between the end surface of the filter member and the filter mounting surface. The filter member according to any one of claims 1 to 3, wherein the filter member is formed by a composite structure of a filtration layer that cannot withstand a filtration pressure by itself and a support that supports the filtration layer. Filter assembly.

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