JPH0628176Y2 - Support structure of porous thin film - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Industrial Application Field) The present invention is a filter element using a flat plate-like porous thin film as a filter medium, and a structure for maximally utilizing an effective membrane area for exerting a filter function. Support the thin film by
The present invention also relates to a support structure of a porous thin film that effectively secures a flow path of a filtered clean fluid.

(Prior Art) In general, the structure of a membrane support used in a single layer or a laminated type of two or more layers using a flat plate-like porous thin film as a filter medium is a rib in which convex protrusions for supporting the membrane are continuous. There are those having (for example, concentric circular ribs) and those having only a large number of outflow ports on the support plate.

In the former support plate having the rib shape described above, the convex portions have a constant width and are continuous, and they are arranged so as to support the entire area of the filter medium at regular intervals, and the ribs are partially filtered. A slit is provided in which the clean fluid communicates with the filter outlet. Further, as the latter, there are a film-like one having a large number of pores communicating with the filter outlet instead of the rib, a porous body, a mesh and the like.

A method in which one layer of the flat plate-like porous thin film is sealed on the outer peripheral edge thereof with a rubber elastic body such as an O-ring or a flat packing using the support as described above is often used in a laboratory. There is. Further, the thin film is bonded and sealed on one or both sides of the support plate with heat, an organic solvent or the like to form a unit, and a filter incorporating an element in which the unit is continuous or laminated by some means is industrial. Used in the level.

(Problems to be Solved by the Invention) The above-mentioned conventional support plate having rib-shaped projections has the following contradictions. is there.

That is, as shown in FIGS. 6A and 6B, in the conventional support plate 22 in which the continuous rib-shaped projections 22a are formed, in order to increase the effective film area of the thin film 21 and increase the flow rate, the rib-shaped projections are required. It is necessary to design the width of the ribs 22a as narrow as possible and the distance between the rib-shaped projections 22a as wide as possible, but on the other hand, the thin film 21 is damaged or bent by the filtration pressure.
There is a possibility that problems may occur such that the support plate 22 comes into close contact with the bottom portion thereof and the flow rate decreases on the contrary (see FIG. 6A).

In order for the thin film 21 to sufficiently withstand the filtration pressure and to avoid the risk of a decrease in the flow rate due to the bottom contact of the support plate 22 due to breakage or bending, the width of the rib-shaped projection 22a should be as wide as possible.
In addition, it is necessary to design the interval between the rib-shaped projections 22a to be narrow, but on the other hand, the thin film 2 due to the close contact between the thin film 21 and the projections 22a.
The problem that the effective film area of No. 1 is reduced occurs (see FIG. 6B).

As is clear from the above description, the thin film 21 and the support plate 22
The rib-shaped projections 22a are uniquely determined by the strength of the thin film 21, and the loss of the film area due to the close contact between the film and the ribs on the support plate is unavoidable to some extent.

In addition, the substantial membrane area becomes large and it cannot be made compact. Furthermore, the fact that the height of the space layer that secures the passage of the clean fluid filtered by the thin film is constant means that the larger the pressure loss is, the smaller the space area is, and the passage resistance is increased. There are various problems such that it may lead to blockage.

The present invention was developed in order to solve the above technical problems, and its purpose is to minimize the contact area between the support and the membrane, and thus to provide an effective membrane support and flow channel. Another object of the present invention is to provide a support structure for a flat plate-like porous thin film, which can be secured, and can achieve a high flow rate and a compact size.

Configuration of the Invention (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention forms a unit member by sealing a flat porous thin film on one or both peripheral edges of a support plate. In a filter element support structure composed of one or more unit members, a large number of protrusions are formed on the porous thin film contact surface of the above-mentioned support plate, and the porous thin film contact surface has a filter element A converging port communicating with the outlet channel is formed, and the projecting portion formed in the vicinity of this converging port is formed to be larger than the projecting portion described above. The protrusions and protrusions formed on the support plate are arranged in an equilateral triangle and discontinuously, and the shape of the protrusions is formed in a hemisphere or arc shape.

(Function) The clean fluid which has passed through the flat porous thin film held by the projection and the projection, which are hemispherical or arc-shaped convex ribs formed on the membrane contact surface of the support, has the projection and the projection. After passing through the flow path which is a space layer with the thin film formed in step (4), the clean fluid flows to the converging port communicating with the filter outlet flow path, and the clean fluid flows out from the filter outlet flow path.

In this state, the flat plate-shaped porous thin film has a protrusion formed in the vicinity of the focusing port formed larger than the other protrusions with respect to an increase in inflow pressure, so that the deflection of the thin film is suppressed,
It is possible to secure stable flow characteristics.

(Embodiment) FIG. 1 is a longitudinal sectional view of a filter in which a filter element constituted by a support of a flat plate-like porous thin film according to the present invention is housed in a housing, and FIG. 2A is a separated perspective view of the element.
2B is a bottom view of the support, FIG. 3 is a partial cross-sectional view of the element, FIG. 4 is a partial plan view showing an example of the support, and FIG. 5 is a part showing another example of the support. It is a top view.

The flat porous thin film 1 is sealed on both sides of the support plate 2 to form the unit member 3, and the unit member 3 is laminated via the spacer 4 having the protrusion 4a to form the filter element 5. . A large number of protrusions 6 are formed on the porous thin film contact surface 2a of the support plate 2 described above, and focusing holes 8a, 8b communicating with the outlet flow path 7 of the filter element 5 are formed on the porous thin film contact surface 2a. To do. Focusing port 8a
Is a hole communicating with both surfaces of the support plate 2, and a plurality of holes are formed in a radial pattern, and the converging ports 8b are holes arranged in the circumference of the filter outlet channel 7 and directly connected to the filter outlet channel 7. The protrusion 9 formed in the vicinity of the focusing ports 8a and 8b is formed larger than the protrusion 6. Also, the focusing ports 8a and 8b
The total opening area of the above must be equal to or larger than the area of the filter outlet channel 7 of one unit member 3. When the converging ports 8a and 8b are formed in an arc shape, the size thereof needs to be φ0, 8 mm or more in view of injection molding. Here, the protrusion 6
An example of the case of arc shape will be described. φ0, 7m
When the protrusions 6 having m, height 0, and 3 mm are arranged in an equilateral triangle with a pitch of 1 and 4 mm, it is difficult to install the focusing port 8 a between the protrusions 6. Therefore, when the focusing port 8a is provided between the protrusions 6, the diagonal distance between the protrusions 6 around the focusing port 8a is 2.8 mm.
In this case, as the inflow pressure increases, the thin film is stretched, and the space layer in the flow channel region is reduced, resulting in the blockage of the flow channel. This phenomenon becomes more remarkable as the thinness of the thin film is weaker, and the flow rate decreases with time even at a constant inflow pressure, and finally reaches a certain flow rate value. Therefore, the protrusion 9 around the focusing port 8a is φ1, 0 mm,
The height was increased to 0, 4 mm. As a result, it was possible to prevent the flow path from being blocked due to the thin film stretching, and it was possible to secure stable flow characteristics even when the inflow pressure increased. Also, the focusing port 8
By providing the vertical rib 8c in the central portion of "a", more stable flow rate identification can be secured. The protrusions 6 and the protrusions 9 thus formed on the support plate 2 are arranged in an equilateral triangle and discontinuously, and the protrusions 6 and the protrusions 9 are formed in a hemispherical shape or an arc shape. The size of the projecting portion 9 has a diameter that is 0, 5 to 10 times the area of the opening of the focusing port, and the height is 0, 2 to 2.
It was confirmed that 2 mm is preferable. Furthermore, the flat plate-shaped porous thin film 1 has a pore size of 0, 01 to 5 μm, an opening ratio of 20% or more,
It is a polymer film with a thickness of 50 to 200 μm, and the material is polymer such as tetrafluoroethylene, cellulose acetate, cellulose nitrate, polypropylene, polyvinyl alcohol, polyamide, polymethylmethacrylate, polysulfone, polyethersulfone, polyvinyl chloride, etc. It should be arbitrarily selected according to the implementation.

In the figure, 10 is a housing for housing the filter element 5, 11 is an O-ring, 12 is a stock solution inlet,
Reference numeral 3 is a clean fluid outlet of the housing 10.

Next, the operation of the above embodiment will be described.

The clean fluid passing through the flat plate-shaped porous thin film 1 held by the projections 6 and the projections 9 which are hemispherical or arcuate convex ribs formed on the membrane contact surface 2a of the support plate 2 is projected. Through the flow path 1a, which is a space layer between the thin film 1 formed by the protrusions 9 and the protrusions 9, to the focusing port 8b communicating with the filter outlet flow path 7, and the clean fluid flows out from the filter outlet flow path 7. Become.

In this state, in the flat plate-shaped porous thin film 1, the protrusions 9 formed near the focusing ports 8a and 8b are formed larger than the other protrusions 6 with respect to the increase of the inflow pressure. It is possible to suppress and secure stable flow characteristics.

Here, the flow rate characteristics of the conventional product and the product of the present invention are shown in the table below.

As is apparent from the above, according to the present invention, the protrusion formed near the focusing port is formed larger than the other protrusions with respect to the increase of the inflow pressure. The contact area of the filter can be minimized, and the deflection of the thin film can be suppressed to ensure stable flow characteristics. In addition, the filter can be made to have a high flow rate and be compact, and it is extremely useful as a filter element. Can be provided.

In particular, carrier gas, etching gas, purge gas, etc. in the field of semiconductors are required to have filters with high cleanliness and low pressure loss as much as possible due to the recent high density and high integration of semiconductors. The present invention can provide a filter that surely satisfies that condition.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention, and FIG. 1 is a vertical cross-sectional view of a filter in which an element constituted by a support of a plate-like porous thin film in the present invention is housed in a housing, 2A is an isolated perspective view of the element of FIG. 1, FIG. 2B is a bottom view of the support in FIG. 2A, FIG. 3 is a partial sectional view of the element, and FIG. FIG. 5 is a partial plan view showing an example of a support, FIG. 5 is a partial plan view showing another example of the support, and FIGS. 6A and 6B are partially enlarged sectional explanatory views of a filter element showing a conventional example. is there. 1 ... Flat porous thin film 2 ... Supporting plate 2a ... Porous thin film contact surface 3 ... Unit member 5 ... Filter element 6 ... Projection 7 ... Filter outlet flow path 8a, 8b ... Convergence port 9 ... Projection

Claims (4)

[Scope of utility model registration request] 1. A flat porous thin film is sealed on both sides of a single support plate to form a unit member, and a large number of protrusions are formed on the porous thin film contact surfaces on both sides of this support plate. With
On this porous thin film contact surface, a converging port communicating with the outlet channel provided in the central part of the support is formed, and among the above-mentioned projecting parts, the projecting part disposed in the vicinity of the converging port is the projecting part. The protrusion is formed to be larger than the other protrusions, the protrusion and the protrusion are arranged in an equilateral triangle arrangement, and the protrusion and the protrusion are formed to have a hemispherical or arcuate cross-sectional shape. A support structure of a porous thin film, characterized in that 2. The size of the projecting portion is 0, which is the area of the aperture of the focusing port,
2. The support structure according to claim 1, having a diameter of 5 to 10 times and a height of 0,2 to 2 mm. 3. The plate-like porous thin film has a pore size of 0, 01 to 5 μm.
The support structure according to claim 1 or 2, which is a polymer film having m, a porosity of 20% or more, and a thickness of 50 to 200 µm. 4. The flat plate-like porous thin film is a polymer such as tetrafluoroethylene, cellulose acetate, cellulose nitrate, polypropylene, polyvinyl alcohol, polyamide, polymethylmethacrylate, polysulfone, polyethersulfone, polyvinyl chloride and the like. Item 3. The support structure according to item 3.