JP2001205011A - Laminated filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact fluid cleaning laminated filter high in regeneration efficiency and easy to manufacture. SOLUTION: A plurality of ring-shaped filter elements 1, each of which has a large number of through-holes 6 having a hole size larger than the particle size of a suspended substance formed therein so that the hole axes of them is turned in the thickness direction of the filter element and has notches 5-1, 5-2 formed to the inner and outer peripheral end parts thereof, are laminated and an inflow part of a liquid to be treated is provided on the side of one of the inner and outer peripheral lamination surfaces of each filter element and an outflow part of the liquid to be treated is provided on the side of the other one of them. Both of the filter elements have the same shape and are laminated in such a state that the center positions of the filter elements 1 are shifted between the adjacent filter elements and the through-holes 6 are partially exposed to the inner and outer peripheral lamination surfaces of the filter elements other than the notches 5-1, 5-2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated filter for purifying water and other fluids, in which a plurality of filter bodies having a ring-like planar shape are laminated.

[0002]

2. Description of the Related Art Conventionally, a filter is used in which a laminated filter is formed by laminating a plurality of flat filter bodies, and a liquid to be treated is introduced and filtered from a direction perpendicular to the laminating direction of the filter bodies. Have been. As such a laminated filter, there is a filter described in, for example, JP-A-10-52608. As disclosed in this publication, a filter having fine pores such as a porous filter medium is generally used as a filter.

[0003]

However, the porous filter material conventionally used as a flat filter has fine pores and depressions smaller than the suspended material, and the suspended material has water flowing through the pores and depressions. And is captured in a compressed state. Therefore, the filter body made of the porous filter medium is easily clogged. In the case of clogging, the rate of regeneration is low with water flow or other physical means, and the only option is to use chemicals or replace the filter.

Further, in order to reduce the size of the laminated filter, it is necessary to increase the filtration area, the passage, and the inflow and outflow holes of the liquid to be treated. In order to increase the number of inflow holes and outflow holes, it is effective to reduce the thickness of each filter and to stack many filters at the same height in the stacking direction. However, when the porous filter medium has a small thickness, the filter body becomes brittle, resulting in insufficient strength. Furthermore, it is very difficult to control and manage the pore size of the micropores and depressions of the porous filter medium, and the production method is also complicated and complicated.

[0005] As described above, the conventional laminated filter using the porous filter medium as a filter has a problem that the regeneration rate of the clogging treatment is low and the obstacle in the production is large.

An object of the present invention is to provide a laminated filter for purifying fluid which is high in regeneration rate, compact and easy to manufacture.

[0007]

According to the present invention, a plurality of through-holes having a diameter larger than the particle size of the suspension are formed with the hole axis oriented in the thickness direction, and are formed at the inner peripheral end and the outer peripheral end. A plurality of ring-shaped filter bodies each having a notch are laminated, and an inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminating surface and the outer peripheral laminating surface, and an outflow portion of the liquid to be treated is provided on the other side. Wherein each of the filter bodies has the same shape and is stacked with a center position shifted between adjacent filter bodies, and the cuts are formed on the inner peripheral laminated surface and the outer peripheral laminated surface. In addition to the notch, the through hole is partially exposed.

According to the present invention, it is possible to obtain a laminated filter for fluid purification which has a high regeneration rate, is compact and easy to manufacture.

In addition, a plurality of through-holes having a diameter larger than the particle diameter of the suspension are formed with the hole axis directed in the thickness direction, and notches are formed at the inner peripheral end and the outer peripheral end, respectively. A multilayer filter in which a plurality of circular ring-shaped filters are laminated, and an inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminating surface and the outer peripheral laminating surface, and an outflow portion of the liquid to be treated is provided on the other side. In addition, each of the filter bodies has the same shape and is stacked with a circumferential lamination angle shifted between adjacent filter bodies, and the inner peripheral laminating surface and the outer peripheral laminating surface have notches other than the notches. The through hole may be partially exposed.

[0010] Even in such a configuration, a laminated filter for fluid purification which has a high regeneration rate, is compact, and is easy to manufacture can be obtained.

[0011]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, a plurality of through-holes having a diameter larger than the particle diameter of the suspension are formed in the thickness direction with the hole axis directed, and the inner peripheral end and the outer peripheral are formed. A plurality of ring-shaped filter bodies each having a notch formed at an end are laminated, and an inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminated surface and the outer peripheral laminated surface, and an outflow portion of the treated liquid is disposed on the other side. Are respectively provided, the filter body has the same shape and the filter body is stacked with the center position shifted between adjacent filter bodies, and the inner peripheral laminated surface and the outer peripheral laminated surface Is a laminated filter characterized in that the through-holes are partially exposed in addition to the cutouts, the through-holes are exposed to the outside with a configuration in which only a part of the filter is shifted, and It has an effect that an inflow portion and an outflow portion can be formed.

According to a second aspect of the present invention, a plurality of through-holes having a diameter larger than the particle diameter of the suspension are formed with the hole axis directed in the thickness direction, and the through-holes are formed at the inner peripheral end and the outer peripheral end, respectively. A plurality of non-circular ring-shaped filter bodies each having a notch are laminated, and an inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminating surface and the outer peripheral laminating surface, and an outflow portion of the liquid to be treated is disposed on the other side. A laminated filter provided, wherein each of the filter bodies has the same shape and is laminated with a circumferential lamination angle shifted between adjacent filter bodies, and the inner peripheral laminated surface and the outer peripheral laminated surface Is a laminated filter characterized in that the through-hole is partially exposed in addition to the notch, the through-hole is exposed to the outside with a configuration in which only a part of the filter is shifted, and the liquid to be treated is Has the function of forming an inflow portion and an outflow portion.

In the present invention, the hole axis is a line segment connecting the centers of the cross sections of the through holes, that is, the center axis, and the center position is the center of the inscribed circle of each ring. The ring shape includes not only a circle but also a polygon and the like, and the non-circular ring shape means a polygon having an outer shape other than a circle.

The through-holes larger than the particle diameter of the suspension are defined as the largest number of average particles when the particle size distribution of the substance to be filtered (assumed removal substance) in the liquid to be treated is taken. On the large particle diameter side based on the diameter (representative value), 40% of the total number of particles on the large particle diameter side (50% as a whole).
%, The pores having a diameter larger than the particle diameter containing 90% (90% is included in the total number). For example, if the liquid to be filtered is bath water and the turbid substance in the bath water is to be filtered, the assumed removal substances are oils and sebum cells (usually 5 to 60 μm in size) coming out of the body. Bacteria (usually 0.3 to 3 μm in size) and hairs larger than this are excluded. In the case where the assumed removal substance is a turbid substance, a through-hole larger than 90% particle diameter of the turbid substance is filtered to remove a turbid substance and a larger suspension such as hair. In the laminated filter of the present invention, the distribution of the overlapping openings (filtration holes) varies depending on the number and distribution of through-holes formed in the filter, and is also affected by the properties of the liquid to be treated. Therefore, when the distribution of the assumed removal substance is abnormally widened to the smaller diameter side, it is effective in some cases to reduce the diameter of the through-hole to a particle diameter near the representative value.

The diameter of the through-hole should be set as a specific example. If the liquid to be treated is bath water, the 90% particle size is 30 to 50 μm. As described above, the assumed removal substance is a turbid substance in the bath water and does not filter bacteria. Assuming that a sufficient number of the through-holes are evenly distributed, the diameter of the through-hole of the filter is 1% smaller than the 90% particle size.
The order of magnitude of about 300 to 700 μm is preferred. When the liquid to be treated is tap water, the 90% particle size is 5 to 10 μm, and in this case, the through-hole diameter of the filter is preferably 50 to 100 μm. In addition, when the liquid to be treated is water in which tap water is stored and residual chlorine has escaped, the assumed removal substance is bacteria, and the 90% particle size is 3 μm. At this time, the through hole of the filter is 20 to 50.
It is preferable to use μm.

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

FIG. 1 is a schematic view of a laminated filter according to an embodiment of the present invention, and FIG. 2 is a laminated plan view of the filter in FIG.

In FIG. 1, the filter body 1 is an annular body having a through-hole 6 (see FIG. 4 described later) with its hole axis directed in the thickness direction thereof. The representative dimensions of the ends are the same. In addition, the filter 1
The shape of the filter is not limited to a circle, and the shapes of the inner peripheral end and the outer peripheral end of all the filter bodies are the same, and the inner peripheral end and the outer peripheral end of each filter 1 are substantially the same at the time of lamination. It is sufficient that they match.

The filter 1 is formed by laminating a plurality of filters in a state where there are no gaps in the thickness direction of the filter 1 so that
The upper and lower ends are held by the non-transmissive upper and lower holding plates 3-1 and 3-2. It should be noted that the uppermost filter body 1-1 of the laminated filter 2 and the upper surface suppressing plate 3-1 are in close contact with each other without any gap, and similarly the lowermost filter body 1-2 of the laminated filter 2 and the lowermost filter body 3-1 are held down. It is in close contact with the plate 3-2 without any gap. Further, the lower surface holding plate 3-2 is a conduit 4 for guiding the liquid to the outside of the multilayer filter 2 to a portion not in contact with the lowermost filter body 1-2.
Are connected in a sealed state. The upper surface pressing plate 3-1 or the upper surface pressing plate 3-1 and the lower surface pressing plate 3-2
May be connected to the pipeline 4 in a sealed state.

A part of the filter body 1 is laminated with the center position shifted from B to A in the direction of the arrow AB from the other filter body 1 like the filter body 1-3. . That is, as shown in the plan view of the filter 1-3 shown in FIG.
The layers are stacked with the center of the outer end shifted in the direction. The direction in which the filter body 1-3 is shifted is not particularly limited,
The surface of the filter 1 may be shifted in any direction in the extending direction. FIG. 3 is a stacked plan view of the filter. For example, as shown in FIG. 3, the filter 1-5, the filter 1-6,
Filter body 1-7, center C-5, C-6, C of filter body 1-8
-7 and C-8, the mutual position is D-E-F-G
The layers can be shifted in the axial direction and can be further shifted in the axial direction. In addition, the number of the filter bodies 1 to be shifted can be adjusted, and all the filter bodies 1 can be shifted, or a configuration in which some of the filter bodies 1 are shifted is also possible.

FIG. 4 is an enlarged view showing a cross section of a portion surrounded by a circle C in FIG. 1, and is a view showing a flow of the liquid to be treated inside the laminated filter. The liquid to be treated flows into the inside of the multilayer filter 2 from the notch 5-1 on the outer peripheral end of the filter 1. The inflowing treated water flows into the filtration passage formed by the through hole 6 overlapping the notch 5-1.
It reaches the inside of the through-hole 6 of the upper or lower filter 1. That is, the number of the through holes 6 overlapping the notch 5-1 is the number of the inflow holes.
Due to the shape of such an inflow hole, the liquid to be treated flows through the through hole 6.
Through the filtration passage formed by the overlap of each other,
It gradually proceeds to the inner peripheral side of the multilayer filter 2. Then, the to-be-processed liquid that has reached the inner peripheral end of the multilayer filter 2 flows out of the multilayer filter 2 through the through-hole 6 that overlaps the notch 5-2 at the inner peripheral end as an outflow hole.

Here, the multilayer filter 2 is formed such that the discharge side cutout 5-2 and a part of the through holes 6 are exposed on the inner peripheral laminated surface, and the supply side notch 5-1 is formed on the outer peripheral laminated surface. And many of the through holes 6 are exposed. An outflow portion that covers the inner peripheral laminated surface 2-2 of the laminated filter 2 and can collect the liquid to be treated after filtration, and the outer peripheral laminated surface 2
An inflow portion that can supply the liquid to be treated over the -1 is provided for water flow. In the present embodiment, the space surrounded by the inner peripheral laminated surface of the upper surface holding plate 3-1, the lower surface plate holding plate 3-2, and the filter 1 constitutes an outflow portion together with the discharge pipe connected thereto. The inlet is not shown in FIG. What is necessary is just a thing like a cover which covers an outer peripheral lamination surface. As described above, the multilayer filter 2 of the present embodiment is configured to flow in from the inflow portion on the outer periphery of the laminate and discharge from the inflow portion inside. However, it is also possible to provide an inflow portion inside the laminate by reversing the flow direction, and discharge from an outflow portion provided outside. At this time, the position of the cutout on the supply side and the cutout on the discharge side are reversed, the cutout on the supply side is formed at the inner peripheral end of the filter 1, and the cutout on the discharge side is the outer end of the filter 1. Part will be formed. In the laminated filter 2 in this case, the supply side notch 5-1 and a large number of through holes 6 are exposed on the inner peripheral laminated surface 2-2, and the discharge side notch is formed on the outer peripheral laminated surface 2-1. 5-2 and some through holes 6
Are exposed. Providing the inflow portion on the outer periphery can increase the filtration area at the time of inflow, and can slightly increase the time until regeneration. However, which side of the inflow portion is to be selected may be selected based on the arrangement of the pipes and the like.

FIG. 5 is an enlarged view of a portion surrounded by a circle H in FIG. 4, and is a schematic view showing a mechanism for filtering a suspension contained in the liquid to be treated. As shown in the drawing, when the liquid to be treated that advances in the direction of the arrow passes through the overlapping portion of the through-holes 6 of the upper and lower two filter bodies 1, a suspension larger than the filtering hole, that is, the overlapping portion of the upper and lower through-holes 6. Are trapped without being able to pass through the filtration hole. Further, the opening area of the filtration hole formed by the overlap of the through holes 6 can be increased or reduced depending on the degree of overlap. Therefore, due to the difference between the size of the formed filtration hole and the size of the through-hole 6, the velocity distribution of the flow of the liquid to be treated is not uniform inside the through-hole 6, and the flow inside the through-hole 6 is not uniform. Stagnation and vortices occur. The stagnation or vortex of the flow of the liquid to be treated thus generated acts to draw a small suspension therein, and the suspension is also trapped by this drawing.

The laminated filter 2 according to the embodiment shown in FIGS. 1 to 5 has a filter body 1 in the form of a ring having the same shape, and the center position is shifted between adjacent filter bodies 1 when laminated. It is. This center position is the center of the circle when the ring shape is circular, but the center of the largest inscribed circle when an inscribed circle is drawn in this shape when the ring shape is a non-circular ring shape It is. When the filter body 1 is laminated in this manner, the filter body 1 in which the inner peripheral end and the outer peripheral end of the filter 1 are adjacent to each other.
The notch 5-1 on the supply side and the notch 5-2 on the discharge side provided at the inner and outer peripheral ends of the inner peripheral laminated surface 2-2 and the outer peripheral laminated surface 2-1 of the laminated filter 2 are shifted. In addition, a part of the through-hole 6 is exposed on the surface which is shifted and exposed. As described above, the laminated filter 2 according to the present embodiment includes a filter hole, a through hole 6, a through hole 6, and a through hole 6, which overlap with each other between a number of adjacent filter bodies 1. The to-be-processed liquid is filtered through a filtration passage formed by the hole 6 and the cutout 5-2 on the discharge side, which is formed in a complicated manner from the supply side to the discharge side. However, in the present embodiment, the inner peripheral laminated surface 2-2 and the outer peripheral laminated surface 2-1 of the laminated filter 2 are arranged.
In addition to the notch 5-1 on the supply side and the notch 5-2 on the discharge side, a part of the through-hole 6 is also exposed on the surface shifted and exposed between the adjacent filter bodies 1. The exposed through-hole 6 is added as a filtration area, so that the filtration flow rate increases and the pressure loss decreases.

In the configuration up to FIG. 5, the filter is formed in a plane shape of an annular circle. However, various shapes as shown in FIGS. The filtering form shown in FIGS. 4 and 5 can be provided by the filtering holes formed by overlapping the through holes.

FIG. 6 is a plan view of a filter having a regular polygonal inner and outer periphery, FIG. 7 is a plan view of a filter having a star-shaped inner and outer periphery, and FIG. 8 is an inner and outer periphery. Is a plan view of a filter body having different shapes, and FIG. 9 is a plan view showing a state in which filter bodies having inner and outer peripheral shapes symmetrical with respect to the center point are shifted around the center point. The filter 1 of FIG. 6 has a regular hexagonal flat shape with an opening at the center and has a uniform distribution of the through-holes 6. FIG. It was done. Also,
As shown in FIG. 8, a planar shape in which the shapes of the inner peripheral surface and the outer peripheral surface are changed may be employed. Further, when the shapes of the inner circumference and the outer circumference are point-symmetric with respect to the center of the virtual circle formed by the outer shape, the filtering bodies 1-9 and 1-11 shown in FIG. By displacing the center point C-9 in the rotational direction, a part of the through hole 6 forming the filtration passage inside the multilayer filter 2 can be exposed to the outer space of the multilayer filter 2, and the inflow hole and the outflow hole It is possible to increase the number of.

In the embodiment shown in FIGS. 6 to 9, the filter bodies 1 are all non-circular ring shapes having the same shape, and the stacking angle is shifted between adjacent filter bodies 1 when they are stacked. ing. When the ring shape is circular, even if the stacking angle is shifted, the exposed surface does not occur due to the shift at the inner and outer peripheral ends. However, when the ring shape is non-circular, the stacking angle is shifted, the inner circumference of the filter body 1 is changed. The end portion and the outer peripheral end portion are displaced between the adjacent filter bodies 1, respectively, and the inner peripheral laminated surface 2-2 and the outer peripheral laminated surface 2-1 of the laminated filter 2 are provided with supply-side cuts provided at the inner and outer peripheral ends. In addition to the notch 5-1 and the notch 5-2 on the discharge side, a part of the through-hole 6 is exposed on the exposed surface that is shifted.

FIG. 10 is a schematic diagram showing a mechanism when a gap is provided between the filter bodies at the time of regeneration and regeneration is performed.

At the time of regeneration by removing the adhered suspended matter from the filter 1, at least a gap is provided between the filter 1 and the suspended body to restrict the suspended matter trapped in the through-hole 6. Solve. When the liquid is flowed in this state, the suspension quickly flows out of the through-hole 6 into the gap between the filter bodies 1 and flows out of the laminated filter 2 to be regenerated. By providing a gap between the filter bodies 1 in this manner, a filter having a very high regeneration rate under low energy can be realized.

FIG. 11 is a sectional view of a main part of a filter having a through hole having one inlet and two outlets. As shown in the drawing, when the liquid enters the through hole 6 from above, the velocity distribution becomes non-uniform due to the disturbance of the flow at the branch portion before the two outlets. As a result, a stagnation or vortex of the flow is generated inside the through-hole 6, and it is difficult for the suspended matter to be taken out of the through-hole 6 when the suspended matter is taken into this. Therefore, the regeneration rate is reduced, and it is preferable that the through-hole 6 has a configuration in which one inlet and one outlet are provided and there is no branch flow path inside.

FIG. 12 is a cross-sectional view of a main part of a filter having a through-hole whose opening cross section is not uniform in the thickness direction. In the through hole 6 having such an open cross section, when the liquid enters from above,
When the flow is disturbed at the widened portion or the narrowed portion of the through hole 6, the velocity distribution is not uniform. Thereby, the through hole 6
A stagnation or a vortex of the flow is generated in the inside of the through hole, and it is difficult for the suspended matter to be taken out of the through hole 6 when the suspended matter is taken into the stagnation. Therefore, the regenerating rate is reduced, and the through-hole 6 preferably has a uniform opening cross section in the thickness direction.

FIG. 13 is a cross-sectional view of a main part showing an arrangement of a filter having a depression formed on the surface in addition to the through hole. Filter 1
Does not have the depression 7, the filtration passage is interrupted where there is no overlap between the through holes 6. On the other hand, filter 1
When the recess 7 is provided, a filtration passage formed by the overlap of the through hole 6 and the recess 7 or the overlap of the recesses 7 is formed, and the water flow resistance can be reduced.

FIG. 14 is a cross-sectional view of essential parts showing an arrangement of a filter body in which through holes are opened in a direction perpendicular to the thickness direction of the filter body in the example of FIG. The through hole 8 is formed so as to have an opening axis that does not coincide with the thickness direction (the vertical direction in the figure) of the filter 1. In the illustrated example, the through hole 8 is formed as an opening axis orthogonal to the thickness direction of the through hole 6. ing. If the filter 1 is not provided with the depression 7 or the through hole 8, the filtration passage is interrupted where the through holes 6 do not overlap. On the other hand, filter 1
In the one provided with the recess 7 and the through hole 8, the through hole 8 is added as a flow path in addition to the filtration passage formed by the overlap of the through hole 6 and the recess 7 or the overlap of the recesses 7.
Thereby, the water flow resistance can be reduced.

[0034]

According to the present invention, a laminated filter having extremely high regeneration efficiency at low energy can be obtained, and a resource saving type laminated filter for fluid purification can be provided which does not require replacement of the filter due to clogging. In addition, there is no restriction on the direction of filtration (flow of liquid) or the direction of mounting the filter, miniaturization with less pressure loss is possible, and its manufacture is facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a laminated filter according to an embodiment of the present invention.

FIG. 2 is a plan view of a stack of the filter in FIG.

FIG. 3 is a plan view of a stacked filter body.

FIG. 4 is an enlarged view showing a cross section of a portion surrounded by a circle C in FIG. 1, showing a flow of a liquid to be treated inside a laminated filter.

5 is an enlarged view of a portion surrounded by a circle H in FIG. 4,
Schematic diagram showing the mechanism by which the suspension contained in the liquid to be treated is filtered

FIG. 6 is a plan view of a filter having a regular polygonal inner and outer periphery.

FIG. 7 is a plan view of a filter having a star-shaped inner and outer periphery.

FIG. 8 is a plan view of a filter having different inner and outer circumferences.

FIG. 9 is a plan view showing a state in which filter bodies having inner and outer peripheral shapes symmetrical with respect to a center point are shifted around the center point and stacked.

FIG. 10 is a schematic view showing a mechanism when a gap is provided between the filter bodies during regeneration and regeneration is performed.

FIG. 11 is a cross-sectional view of a main part of a filter having a through hole having one inlet and two outlets.

FIG. 12 is a cross-sectional view of a main part of a filter body having a through hole whose opening cross section is not uniform in the thickness direction.

FIG. 13 is a cross-sectional view of a main part showing an arrangement of a filter body having a depression formed on the surface in addition to a through hole.

FIG. 14 is a cross-sectional view of a main part showing an arrangement of a filter body in which through holes are opened in a direction perpendicular to the thickness direction of the filter body in the example of FIG. 13;

[Explanation of symbols]

1,1-1,1-2,1-3,1-4,1-5,1-
6, 1-7, 1-8, 1-9, 1-10, 1-11 Filter 2 Laminated filter 2-1 Outer lamination surface 2-2 Inner perimeter lamination surface 3 Holding plate 3-1 Top holding plate 3- 2 Lower surface holding plate 4 Pipeline 5 Notch 5-1, 5-2 Notch 6 Through hole 7 Depression 8 Through hole C-5, C-6, C-7, C-8, C-9 Center point

Claims (2)

[Claims] 1. A ring in which a plurality of through-holes having a diameter larger than the particle diameter of a suspension are formed with a hole axis directed in a thickness direction, and a notch is formed at each of an inner peripheral end and an outer peripheral end. A filter in which a plurality of filter bodies each having a shape are laminated, and the inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminating surface and the outer peripheral laminating surface, and the outflow portion of the liquid to be treated is provided on the other side.
Each of the filter bodies has the same shape and is stacked with the center position shifted between adjacent filter bodies, and the through-hole is provided in addition to the notch on the inner peripheral laminated surface and the outer peripheral laminated surface. A laminated filter that is partially exposed. 2. A non-aperture, wherein a plurality of through-holes having a diameter larger than the particle diameter of the suspension are formed with the hole axis directed in the thickness direction, and notches are formed at an inner peripheral end and an outer peripheral end, respectively. A multilayer filter in which a plurality of circular ring-shaped filters are laminated, and an inflow portion of the liquid to be treated is provided on one side of the inner peripheral laminating surface and the outer peripheral laminating surface, and an outflow portion of the liquid to be treated is provided on the other side. In addition, each of the filter bodies has the same shape and is stacked with a circumferential lamination angle shifted between adjacent filter bodies, and the inner peripheral laminating surface and the outer peripheral laminating surface have notches other than the notches. Wherein the through-hole is partially exposed.