JP2003230822A - Porous filter and water purifier, and filter inspection device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous filter having excellent bacteria-removing performance, a water purifier provided with the filter, an inspection device, which can simply probes the performance of the filter, and an inspection method. <P>SOLUTION: This porous filter 1 includes: a porous substrate comprising at least two end faces 41, 43 and a large number of flow passages 3a, 3b extending from one of the end face 41 to the other end face 43; and a filtration membrane 9 provided on the inner periphery of a part of the flow passages 3a, 3b. The porous filter and the water purifier are characterized in that, when the surface of the porous substrate is pressurized by air, the initial pressure of air which flows from any of the flow passages 3b provided with the filtration membrane, is 0.05 to 0.6 MPa. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention firstly relates to a porous filter for filtering a fluid, and more particularly to a porous filter which is excellent in sterilization performance and can be suitably used for filters such as water purifiers. The present invention secondly relates to a water purifier provided with the above filter. Thirdly, the present invention relates to a porous filter inspection device capable of easily measuring the performance of the porous filter in a short time. Fourthly, the present invention relates to a method for inspecting a porous filter, which can easily measure the performance of the porous filter in a short time.

[0002]

2. Description of the Related Art A filter made of a porous body having a large number of flow passages is generally made of a material such as ceramics which is hard to be deformed and has high durability, and has a physical strength higher than that of a polymer membrane or the like. In terms of high reliability due to excellent durability, low deterioration due to high corrosion resistance even after washing with acid / alkali, etc. Furthermore, it is possible to precisely control the pore size that determines the filtration capacity. Since it is excellent, it is used in various filters, particularly useful as a filter for solid-liquid separation and the like, and is also beginning to be used in water purifiers and the like.

A porous filter made of ceramics or the like performs filtration using a porous material processed into various shapes such as a flat plate shape and a tube shape as a filtering material, but has a large filtering area per unit volume, and thus filtration processing is performed. In terms of high performance, a so-called monolith type filter, in which a large number of flow passages (cells) serving as flow passages for filtered fluid are formed in a cylindrical base material made of a porous body, is widely used particularly for solid-liquid separation. ing. When using such a filter in a water purifier or the like, disinfection performance is important.

[0004]

The present invention has been made in view of the above-described requirements, and an object of the present invention is to provide a porous filter excellent in sterilization performance and a water purifier equipped with the filter. An object of the present invention is to provide an inspection device and an inspection method for a porous filter capable of easily measuring the performance of the filter in a short time.

[0005]

Means for Solving the Problems The first aspect of the present invention is to provide a porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to another end face, and a part of the flow passages. A porous filter having a filtration membrane formed on an inner peripheral surface, wherein when the surface of a porous substrate is pressurized with air, air first flows out from any flow passage in which the filtration membrane is formed. The pressure applied is 0.05 to 0.6 MPa or more, and a porous filter is provided (first invention).

In the first invention, the pressure at which air flows out from all the flow passages in which the filtration membrane is formed is 0.15.
It is preferably ˜0.6 MPa. Further, it is preferable that a predetermined flow passage is sealed at at least one end face, further, a predetermined flow passage is sealed at one end face, and a remaining flow passage is sealed at the other end face, In particular, it is preferable that the flow passages that are linearly adjacent to each other be sealed at one end face. Further, the flow passage inner peripheral surface sealed at one end face has a portion where the filtration membrane is not formed, and the flow passage inner peripheral surface sealed at the other end face is provided with the filtration membrane. Preferably, the filter is a water purifier filter.

Secondly, the present invention provides a water purifier provided with the above-mentioned porous filter (second invention).

Thirdly, the present invention is formed on a porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to the other end face, and formed on an inner peripheral surface of a part of the flow passages. An inspection device for a porous filter having a filtration membrane, the pressurizing means for pressurizing a predetermined surface of the porous filter with a gas, and the detecting means for detecting the gas flowing out from the other surface as bubbles in the liquid. An inspection device for a porous filter is provided (3rd aspect).
Invention). In the third invention, it is preferable that the predetermined surface is a porous substrate surface on which a filtration membrane is not formed.

Fourthly, the present invention is formed on a porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to the other end face, and a part of the inner peripheral surface of the flow passages. A method for inspecting a porous filter having a filtration membrane, the method comprising: a pressurizing step of pressurizing a predetermined surface of the porous filter with a gas; and a pressurized gas flowing out into a liquid from another surface. The present invention provides a method for inspecting a porous filter, which comprises a detection step of detecting air bubbles (fourth invention). In the fourth invention, it is preferable that the predetermined surface is a porous substrate surface on which a filtration membrane is not formed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments. It should be understood that design changes, improvements, etc. can be appropriately made based on the knowledge of. In the present invention, the cross section means a cross section perpendicular to the longitudinal direction of the flow passage (X-axis direction in FIG. 1) unless otherwise specified.

The porous filter 1 of the first invention is composed of at least two end faces 41 and 43 and one end face 4 as shown in FIGS. 1 (a), 1 (b), 1 (c) and 1 (d).
A porous substrate having a large number of flow passages 3a and 3b communicating from 1 to the other end surface 43, and a part of the flow passage, for example, FIG.
It is the porous filter 1 which has the filtration membrane 9 formed in the inner peripheral surface of the flow path 3b in (b). The important feature of the first invention is that the surface of the porous substrate of the porous filter 1, that is, the surface on which the filtration membrane 9 is not formed, such as that shown in FIG.
When the inner peripheral surface and the side surface 7 of the flow passage 3a in (a) are pressurized with air, air is first supplied from any of the flow passages in which the filtration membrane is formed, for example, the flow passage 3b in FIG. 2 (a). The pressure at which the water flows out (hereinafter referred to as the first permeation pressure) is 0.
05-0.6MPa, preferably 0.08-0.4MP
a, more preferably 0.1 to 0.2 MPa.

It is considered that the sterilization performance of the porous filter depends on the maximum pore size, the average pore size, the pore size distribution, the film thickness, etc. of the filtration membrane. Performance is expected to improve. However, it is difficult to elucidate the contribution of each factor to the sterilization performance as a whole and the interaction of each factor.

Therefore, as a result of the examination by the present inventor,
It is found that the permeation pressure is closely related to the sterilization performance of the filter as a whole, and the first permeation pressure is 0.05MP
It has been found that excellent sterilization performance can be obtained by setting a or more, preferably 0.08 MPa or more, and more preferably 0.1 MPa or more.

It is considered that the first permeation pressure is closely related to the relatively large pores and the membrane thickness of the filtration membrane. Therefore, it is considered that the first permeation pressure is increased by decreasing the maximum pore diameter, reducing the number of large pore diameters, and increasing the thickness of the filtration membrane. Further, if the first permeation pressure is too high, the amount of water permeation decreases, which is not preferable. Therefore, the first permeation pressure is preferably 0.6 MPa or less, more preferably 0.4 MPa or less, and particularly preferably 0.2 MPa or less.

From the viewpoint of further improving the purification performance, the pressure (hereinafter referred to as the second permeation pressure) when air flows out from all the flow passages formed on the inner peripheral surface of the filtration membrane is 0.
15 MPa or more, more preferably 0.17 MPa or more, and especially 0.1.
It is preferably 2 MPa or more. The second permeation pressure is considered to have a large relationship with the average pore size and the film thickness of the filter, and the second permeation pressure can be increased by decreasing the average pore size or increasing the film thickness. . If the second permeation pressure is too high, the amount of water permeation is reduced, which is not preferable, and is preferably 0.6 MPa or less, more preferably 0.5 MPa or less, and particularly preferably 0.3 MPa or less.

The average pore size of the filtration membrane is
It can be appropriately selected depending on the purpose, but in order to keep the first permeation pressure within the range of the present invention, the average pore diameter of the filtration membrane is 0.1 to 2.0 μm, and further 0.2 to 0. It is preferable that the diameter is about 7 μm and the pore size distribution is sharp.
The thickness of the filtration membrane is not particularly limited, but is preferably about 30 to 600 μm in order to keep the first permeation pressure within the range of the present invention.

The material of the filtration membrane is not particularly limited, but it is preferable that the filtration membrane contains ceramic particles and a sintering aid for the filtration membrane. Ceramic particles are particles that constitute the main component of the filtration membrane, such as alumina, mullite, cordierite,
Particles of one kind or two or more kinds of silicon carbide, silicon nitride, aluminum nitride, ceramics scraps and the like are preferable and appropriately selected so as to meet the purpose of filtration. As ceramic particles,
By selecting a smaller particle size, the pore size after firing becomes smaller. Therefore, it is possible to select particles having an appropriate average particle size and particle size distribution so that the pore size falls within the above range. . A specific preferable average particle diameter of the ceramic particles is about 0.1 to 10 μm. The sintering aid for filter membranes is used for strengthening the bond between the ceramic particles by firing together with the ceramic particles to form a strong filter membrane. The material is not particularly limited, but for example, one or more of alumina, silica, zirconia, titania, glass frit, feldspar, cordierite, etc. can be used, and is appropriately selected depending on the purpose of filtration and the material of the ceramic particles. be able to. The ratio of the ceramic particles and the sintering aid for the filtration membrane is preferably 85 to 99.5 based on the total amount of the ceramic particles and the sintering aid for the filtration membrane.
%, And the sintering aid for the filtration membrane is preferably 0.5
~ 15% by mass. The filtration membrane can be formed by applying the ceramic particles and the sintering aid for the filtration membrane in the form of slurry to the surface of the substrate and then firing the slurry.

Further, the filtration membrane preferably has a pore size smaller than that of the porous substrate. With such a configuration, the sterilization performance can be improved while suppressing the pressure loss. In this case, as shown in FIG.
It is preferable to allow the unfiltered fluid to flow in from the flow passage 3b in which the filtration membrane 9 is formed, in order to efficiently achieve the above object.

The material of the porous substrate (hereinafter referred to as the substrate) in the first invention is not particularly limited as long as it is a porous body, but ceramics are preferable from the viewpoint of strength and durability. The pore size of the substrate can be appropriately selected according to the purpose and application of the filter. Further, when the substrate is ceramics, the kind and manufacturing method are not particularly limited, but in general, it is preferably formed from an aggregate and a sintering aid for a substrate.
For the aggregate, it is preferable to select and use from the above-mentioned materials mentioned as preferable examples for the ceramic particles. However, the preferable average particle size is about 5 to 200 μm. The content of the aggregate in the substrate is preferably 65 to 99.5% by mass, based on the total amount of the aggregate and the sintering aid for the substrate.
Is. The sintering aid for the substrate is also preferably selected and used from the materials listed as being preferable as the sintering aid for the filtration membrane. The average particle size of the sintering aid for the substrate is not particularly limited, but an average particle size of 5 μm or less is preferable.
The content of the sintering aid for the substrate is preferably 10 to 35% by mass, based on the total amount of the aggregate and the sintering aid for the substrate.
The base material of the porous ceramics filter can be formed by forming the clay containing the aggregate and the sintering aid into an arbitrary shape and then firing it.

In the first invention, the cross-sectional shape of the flow passage is not particularly limited, and may be any polygon such as a triangle, a quadrangle, a pentagon, and a hexagon, as well as a circle, an ellipse, a corrugated shape, and the like. However, a circular shape or a substantially circular shape is preferable from the viewpoint of the strength of the substrate and the filtration membrane and the viewpoint that the filtration membrane can be uniformly formed on the inner peripheral surface. Here, the substantially circular shape includes an elliptical shape, an oval shape, an oval shape, and the like, as well as a shape in which polygonal vertices are rounded. The cross-sectional area of the flow passage is not particularly limited, but if it is too small, the resistance at the time of inflow of the fluid before filtration becomes too large, which is not preferable, and if it is too large, a sufficient filtration area cannot be obtained, which is not preferable. Although the preferable range of the cross-sectional area of the flow passage 3 varies depending on the viscosity of the filtered fluid, for example, when the filter of the present invention is used in a water purifier, it is preferably 0.2 to ²⁰ mm ² , more preferably 0.5 to 10 mm ^2. Can be By setting it in such a range, it is easy to uniformly form a film when forming the filtration membrane, and a membrane area per unit volume can be made relatively large, that is, the filter can be made compact. Further, the number of flow passages is not particularly limited and can be appropriately selected by those skilled in the art from the relationship of strength, size, and throughput.

The shape of the porous filter in the first invention is preferably a cylindrical shape as shown in FIG. 1 (a), but there is no particular limitation, and any shape is possible depending on the application / purpose, installation location, etc. Can be Also, the size can be appropriately selected according to the processing amount, the installation place, and the like.

The porous filter of the first invention has a predetermined flow passage at least at one end surface, for example, as shown in FIG.
As shown in (a), the flow passage 3b is preferably sealed at the end face 43. With such a configuration,
When the unfiltered fluid is caused to flow into the flow passage 3b from the end face 41, the entire amount of the unfiltered fluid that has flowed in passes through the filtration membrane formed on the inner peripheral surface of the flow passage 3b and the substrate, and flows out, for example, from the side surface 7. It is possible to filter the whole amount of the unfiltered fluid that has flowed in. Further, as shown in FIG.
It is preferable that the remaining flow passage 3a is sealed. With such a configuration, the filtered fluid also flows out from the flow passage 3a, and the processing capacity can be improved by ensuring the outflow passage inside the filter. Further, it is preferable to have a portion where the filtration membrane is not formed on the inner peripheral surface of the flow passage 3a which is sealed at the end surface 41 and through which the fluid after filtration is discharged, in order to suppress pressure loss. From the above viewpoint, the area of the inner peripheral surface of the flow passage 3a in which the filtration membrane is not formed is preferably 50% or more, more preferably 70% or more, and most preferably 80% of the total area of the inner peripheral surface of the flow passage 3a. % Or more. The filtration membrane may have one layer, but may have two or more layers. In that case, the average pore diameter of the outermost filtration membrane should be minimized, and the pore diameter should be increased toward the substrate. Is preferred.

Further, it is preferable from the viewpoint of ease of production that the adjacent flow passages that are linearly adjacent to each other be sealed on one end face. When a series of flow passages that are continuously adjacent to each other in a sealed line form is regarded as one line, it is preferable that the number of flow passages that constitute this one line is three or more. Furthermore it is sealed from the flow passage 3a _o, the end face 41 of the flow passage is one of successive adjacent to the flow passage 3a o _'which is located in any other outermost located any outermost side Are preferable from the viewpoint of ease of production. Similarly, from the viewpoint of ease of manufacturing, the flow passages 3a sealed at the one end face 41 are preferably flow passages that are linearly and continuously adjacent to each other, but are continuously curved and adjacent to each other. It may be a flow passage or a flow passage that is adjacent in a polygonal shape. In addition, in FIGS. 1A to 1D, a circle shown by a dotted line indicates a flow passage sealed at its end face, and a black circle indicates a flow passage opened at the end face.

In addition, a series of flow passages that are continuously adjacent to each other in the sealed line shape are regarded as one line, and this is divided into two lines.
In the case of providing more than one, it is preferable to provide them at regular intervals from the viewpoint of improving the processing capacity by uniform discharge. Specifically, if the series of flow passages 3a sealed at the one end face 41 is one line, as shown in FIGS. 1 (a) to 1 (d), in addition to the configuration in which they are provided substantially in parallel, The lines may be provided so as to intersect with each other, or they may be combined. Further, it may be combined with the case where the series of lines of the flow passage 3a are provided in a curved shape or a polygonal shape, and the form thereof is not particularly limited. Flow passage 3 sealed at one end face 41
The number of a is not particularly limited, but if the number is too large, the number of inflow ports will be small, and if it is too small, a sufficient discharge amount cannot be obtained. The number can be appropriately selected depending on the processing capacity and the size of the filter, but with respect to the total cross-sectional area of the flow passages, that is, the total cross-sectional area of openings of the flow passages 3a and 3b
The number can be selected so that the cross-sectional area is preferably 2 to 20%, more preferably 6 to 15%, and most preferably 8 to 11%.

The material of the sealing layer formed by sealing is not particularly limited, but when the substrate is ceramics, it is preferably ceramics from the viewpoint of strength and adhesiveness to the substrate. More preferably, it is a ceramic containing the same components as some of the components contained therein. However, since it is necessary that the filtered fluid is not substantially permeated, a frit containing ceramics such as frit, particularly silica and alumina as main components, and containing 10% by mass or less of zirconia, is fritified. Glaze and the like are preferable.

By sealing a predetermined flow passage,
For example, the seal layer 5 is formed at the tip of the flow passage 3a in FIG. 2B, but the fact that the plugging portion 6 is formed in the inner direction of the flow passage of the seal layer improves the strength and sealability of the seal layer. From the viewpoint of. There is no particular limitation on the material of the plugged portion, but when the base is ceramics, it is preferable that it is ceramics from the viewpoint of strength and adhesiveness to the base, and the same components as some of the components contained in the base More preferably, it is a ceramic containing However, if the material through which the filtered fluid easily permeates is used, the fluid may leak from the adjacent flow passages at the end faces through the plugged portions, which is not preferable. Therefore, it is preferable to have the same or smaller pore size as that of the filtration membrane, and it is more preferable that there is substantially no pore and the fluid is not permeated. On the other hand, it is preferable that the material of the filling portion is a material having a small shrinkage because if the shrinkage is too large, a crack is likely to occur.
Specifically, it is preferable that a fritted glaze or the like, in particular, a fritted glaze or the like containing silica and alumina as main components and containing 10% by mass or less of zirconia, is the only glaze. More preferably.

Next, a method for manufacturing the porous filter of the first invention will be briefly described. For example, the above-mentioned preferable ratio of the aggregate and the sintering aid for the substrate selected from the above-mentioned preferred aggregate for the substrate and the preferred sintering aid for the substrate (aggregate: sintering aid for the substrate = 65 to 99. 5% by mass: 35 to 0.5% by mass), a dispersion medium, an organic binder, and if necessary, a surfactant, a plasticizer, etc. are added thereto and kneaded to form a clay. For example, this is extruded into a cylindrical shape having a large number of circular flow passages, dried and cut into a predetermined length to obtain a molded body of the substrate, and then the selected aggregate and sintering are performed. Predetermined temperature and time depending on the auxiliary agent, for example 1000 to 16
The substrate can be formed by baking at a maximum temperature of 00 ° C. for 0.1 to 3 hours.

A filtration membrane is formed on the obtained substrate. For example, ceramic particles alone selected from the ceramic particles preferable for the above-mentioned filtration membrane, or a sintering aid selected from this ceramic particle and the above-mentioned preferable sintering aid for the filtration membrane may be used for the ceramic particles / filtration membrane. A mass ratio of the sintering aids is preferably 75 to 98/25 to 2, more preferably 80 to 95/20 to 5, and the mixture is mixed in a dispersion medium such as water. If necessary, an organic binder, a pH adjuster, a surfactant, an antifoaming agent, etc. are added to prepare a film-forming slurry, which is applied to the surface of a predetermined substrate, dried, and then selected ceramic particles and baking are performed. Predetermined temperature and time depending on the auxiliary agent, for example, 900 to 1450 ° C
The filtration membrane can be formed by holding at the highest temperature of 0.1 to 3 hours and baking. The method for applying the film-forming slurry to the surface of the substrate is, for example, a method in which the film-forming slurry is brought into contact with the surface on which the filtration membrane is to be formed and pressure is applied from the surface on which the filtration membrane is to be formed. Examples include a method of reducing the pressure from the surface side. Specifically, the direct filtration method film forming method and the cross flow film forming method are particularly preferable when the slurry is applied to the inner peripheral surface of the flow passage to form the filtration film. In this case,
In order to prevent the filtration membrane from being formed in the predetermined flow passage, it is preferable to seal the predetermined flow passage.

Next, the end surface of the obtained filter is sealed. For example, in the end surface 41 of FIG.
When a is sealed, the other flow passage 3b is masked with, for example, a masking tape, and the frit is made into a glaze or the like, particularly silica and alumina as the main components, and a frit containing 10% by mass or less of zirconia. The applied glaze or the like, or a film-forming slurry similar to that used in the above-mentioned film-forming step is applied by, for example, a spray method, dried, and then baked at a predetermined temperature for a predetermined period of time to flow through the end face 41. The passage 3a can be sealed, and the other end surface 43 can be similarly sealed. In this case, for example, using alumina or silica as a main raw material, adding a polyvinyl alcohol solution, etc., and packing a packing agent having a viscosity higher than that of the slurry into the flow passage to be sealed, and then applying the film-forming slurry. It is preferable to apply it because a uniform seal layer can be formed in a short time.

Hereinafter, a water purifier provided with the filter according to the second invention will be described. The porous filter of the first aspect of the invention is excellent in sterilization performance, and thus can be suitably used for a water purifier, particularly a household water purifier. When used in a water purifier, the filter of the present invention may be attached to a housing surrounding a filter and provided with an inlet and an outlet.
It is also preferable that the water purifier of the present invention further includes other purification / sterilization means, for example, activated carbon. FIG. 3 shows an example of a water purifier provided with the porous filter of the present invention. Activated carbon 212 is arranged in the lower part, and the porous filter 1 of the present invention is arranged in the upper part thereof. Water before filtration is inflow pipe 200
From the lower end surface 41 of the filter 1 through the activated carbon layer 212, the filtered purified water flows out from the side surface 7 or the upper end surface of the filter 1, and is discharged through the discharge pipe 226. To be done.

Hereinafter, a porous filter inspecting device according to a third aspect of the present invention, which is capable of suitably measuring the above-described first and second permeation pressures, will be described based on preferable specific examples. FIG. 4 shows a preferred example of the inspection device of the third invention. The inspection apparatus shown in FIG. 4 includes a pressurizing chamber 302 and a filter base 3 for mounting a porous filter arranged in the pressurizing chamber.
04, an air compressor 30 that is connected to a cylinder 306 that is connected to the filter base 304 so as to move the filter base 304 up and down, and communicates with the pressurizing chamber 302 and that includes a regulator.
8. The liquid receiver 312 is provided above the pressurizing chamber so that the end surface of the filter 1 and the liquid can come into contact with each other.

As the pressurizing means, as shown in FIG.
Pressurization chamber 302 and air compressor 30 communicating with it
8 is preferable, and by pressurizing the pressurizing chamber by the air compressor 308, it is possible to uniformly pressurize a predetermined surface of the porous filter, for example, the side surface 7 and the inner peripheral surface of the flow passage 3a. The pressurizing unit is not particularly limited as long as it can pressurize a predetermined surface with gas, and a cylinder or the like can be used instead of the air compressor. In addition, it is preferable to provide a regulator, a pressure gauge, or the like, because accurate pressure can be applied and the pressure can be measured. The type of gas to be pressurized is not particularly limited, but air is the easiest to handle and is preferred.

The detection means is not particularly limited as long as it can detect the outflowing gas as bubbles in the liquid, but as shown in FIG. 4, the liquid 3 can be placed on the end face 41 of the filter.
It is preferable to include a liquid receiver 312 or the like capable of contacting 10 with each other. Liquid receiver 31 having such a configuration
When the liquid 310 is put in 2, the gas flowing out from the other surface, that is, the surface which is not pressurized can be detected as bubbles.
The liquid for detecting the gas is not particularly limited, but water is the easiest to handle and is preferable.

In the third invention, it is also preferable to provide seal members 314 and 316 arranged so that the pressure chamber can be made airtight when the filter is set in the pressure chamber 302. Further, the predetermined surface of the porous filter to be pressed is preferably the surface of the porous substrate on which the filtration membrane is not formed. Since the porous substrate has many pores, if pressure is applied from the surface of the filtration membrane, it takes time for the gas that has permeated the filtration membrane to be discharged through the porous substrate, but the porous membrane without the filtration membrane is formed. When pressure is applied from the surface of the base material so that the gas flows out from the surface of the filtration membrane, the gas that has permeated the filtration membrane is immediately discharged, so that the inspection time can be shortened.

Hereinafter, a method for inspecting a porous substrate which is the fourth invention capable of suitably measuring the first permeation pressure and the second permeation pressure will be described based on a preferable concrete example using the apparatus having the above-mentioned configuration. . For example, a porous filter having a configuration as shown in FIGS. 1A to 1D is set on the filter receiver 304 in the pressurizing chamber in FIG. 4, and the porous filter is raised by the cylinder 306 to apply pressure. After the chamber is made airtight, a liquid, preferably water, is added to the liquid receiver 312 to bring it into contact with the liquid and another surface, that is, a surface from which gas flows. Here, it is not necessary to bring all the surfaces through which the gas flows out into contact with the liquid. For example, in FIG. 4, the actual gas outflow surface is the inner peripheral surface of the flow passage 3b, but up to the inside of the flow passage 3b. Even if the gas is not filled with the liquid, the gas flowing out from the inner peripheral surface of the flow passage 3b flows out of the end face 41 into the liquid through the flow passage 3b. You can reach your purpose.

Next, the air compressor 308 is operated to gradually increase the pressure in the pressurizing chamber 302. At this time, the pressure at the time of first detecting the bubbles flowing out from at least one flow passage 3b becomes the first permeation pressure. The pressure at the time when the pressure is further increased and the bubbles flowing out from all the flow passages 3b are detected becomes the second permeation pressure. Here, the predetermined surface to be pressurized in the pressurizing step is the porous substrate surface on which the filtration membrane is not formed, and the gas outflow surface is formed with the filtration membrane, for the reason explained in the third invention. It is preferable that it is a surface. A method of increasing the pressure to a preset pressure and checking whether bubbles are detected at the pressure is also preferable for quality control.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail based on examples. (Example 1) 90% by mass of alumina having an average particle diameter of 50 μm as an aggregate, and 10% by mass of a Gyrome system as a sintering aid
Then, about 15 parts by weight of water is added to 100 parts by weight of the total, and these are kneaded with a kneader. Further, 5 parts by weight of methyl cellulose as an organic binder and 1 part by weight of fats and oils are added and kneaded to form a cup for extrusion. Soil was prepared. Next, using a vacuum kneader, a columnar molded body having a diameter of about 130 mm and a length of 350 mm was molded at a temperature of 0 to 5 ° C. Then, using a ram type molding machine, this molded body was molded into a filter molded body having 1200 flow passages having a diameter of 2 mm and having a diameter of 90 mm and a length of 180 mm.
It was dried for 20 hours. This was baked at 1250 ° C. for 1 hour to prepare a porous substrate.

Next, as a raw material, an alumina binder having an average particle diameter of 5 μm was added with an organic binder at 1% by mass and water at 80% by mass to prepare a film-forming slurry, and a cross-flow filtration device shown in FIG. Immediately after pressing the film-forming slurry into the flow passage of the obtained porous substrate, the pressure inside the vacuum chamber 106 is reduced by the vacuum pump 113 until the film-forming raw material having a predetermined film thickness adheres to the substrate. The film slurry was circulated to form a film on the inner wall surface of the flow passage. After that, the slurry in the substrate was discharged, and the inside of the substrate was kept at normal pressure, and the inside of the vacuum chamber was depressurized to perform vacuum drying for about 10 minutes. Furthermore,
After being dried at 60 ° C. for 20 hours, it was baked at 950 ° C. for 1 hour to form a filtration membrane having a film thickness of about 180 μm in the flow passage corresponding to the flow passage 3b in FIG. 1 (a).

Next, 65% by mass of SiO ₂ and Al ₂ O ₃
Of frit 100 containing 20% by mass and 5% by mass of ZrO _2.
A sealing agent obtained by adding 90 parts by mass of a 1.5% by mass aqueous solution of methylcellulose to parts by mass is sealed at one end face of the flow passage corresponding to the flow passage 3a and at the other end face of the flow passage corresponding to the flow passage 3b. After sealing, the substrate was fired at 950 ° C. for 1 hour to obtain a porous filter.

(Example 2 and Comparative Examples 1 and 2) Example 2
As a comparative example 1 and 2, a porous filter was prepared in the same manner as in Example 1 except that the membrane pressure of the filtration membrane was 150 μm.
A porous filter was prepared in the same manner as in Example 1 except that m was used.

The porosity obtained using the apparatus shown in FIG.
The first and second permeate pressures of the quality filter were measured. Well
According to JIS S3201 Annex 9,
1 x 10 Pseudomonas⁶Raw water containing pieces / ml
Pass through each filter to determine the number of Pseudomonas bacteria in the filtered water.
The bacterial trapping performance was measured by investigating. Each result
Is shown in Table 1. From Table 1, the fluxes obtained in Examples 1 and 2
Ilta contains less than 10 Pseudomonas / ml,
Pseudomonas reduction rate is 1/10 ^FiveWhat to do
Was obtained, and excellent sterilization performance was exhibited. On the other hand, a comparative example
The porous filters obtained in 1 and 2 are
2 Both the permeation pressure was low, and the disinfection performance was inferior.

[0042]

[Table 1]

[0043]

As described above, in the porous filter of the present invention, the first permeation pressure is 0.05 to 0.6 MPa.
Therefore, excellent sterilization performance was exhibited. Moreover, the water purifier of this invention is excellent in sterilization. Further, the inspection method and apparatus of the present invention made it possible to measure the first and second permeation pressures easily and in a short time.

[Brief description of drawings]

1A and 1B are views showing an embodiment of a porous filter of the present invention, in which FIG. 1A is a perspective view seen from one end face side, FIG. 1B is a plan view thereof, and FIG. 1C is another end face side. Perspective view seen, (d)
Is a plan view thereof.

2A is a sectional view taken along line II-II of FIG. 1B, and FIG. 2B is an enlarged view of a portion II (b) of FIG.

FIG. 3 is a schematic cross-sectional view showing an example of a water purifier of the present invention.

FIG. 4 is a schematic cross-sectional view showing an example of the inspection device of the present invention.

FIG. 5 is a schematic view showing an example of a film forming apparatus used for forming a gas film.

[Explanation of symbols]

1 ... Porous filter, 3 ... Flow passage, 3a ...
Adjacent flow passage, 3a _o3a_{o '}... outermost out of 3a
Circumferential flow passages, 3b ... remaining flow passages, 5 ... seal
Layer, 6 ... Clogged portion, 7 ... Side surface, 9 ... Filtration membrane, 11 ... Porous
Quality substrate, 41, 43 ... End face, 102, 103 ... Franc
J, 106 ... Vacuum chamber, 107 ... Slurry pump,
108 ... Storage tank, 109 ... Slurry, 113 ... Vacuum pump
200, inflow pipe 201, top cover, 202 ...
Bottom cover, 205 ... Nonwoven fabric, 206 ... Sponge, 2
08 ... O-ring, 210 ... Check valve, 212 ... Activated carbon, 2
14 ... Base, 218 ... Cover holder, 219 ... Hold
Darnut, 220 ... Foot rubber, 221 ... Water purification connector
-223 ... Water discharge connector, 224 ... Connector holder
Dar, 225 ... Pipe cover, 226 ... Water discharge pipe, 228
... O-ring, 302 ... Pressurizing chamber, 304 ... Filter stand, 3
06 ... Cylinder, 308 ... Air compressor, 31
0 ... Liquid, 312 ... Liquid receiver.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4D006 GA07 HA77 JA02A JA03A                       JB01 KA64 KE07Q LA06                       MA04 MA09 MB02 MC03 MC03X                       NA39 NA46 PA01 PB06 PB24                       PC52

Claims (12)

[Claims] 1. A porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to another end face, and a filtration membrane formed on an inner peripheral surface of a part of the flow passages. In the porous filter having the above, when the surface of the porous substrate is pressurized with air, the pressure at which air first flows out from any of the flow passages in which the filtration membrane is formed is 0.05 to 0.
A porous filter having a pressure of 6 MPa. 2. The porous filter according to claim 1, wherein the pressure at which air flows out from all the flow passages in which the filtration membrane is formed is 0.15 to 0.6 MPa. 3. The porous filter according to claim 1, wherein a predetermined flow passage is sealed on at least one end surface. 4. The porous filter according to claim 3, wherein a predetermined flow passage is sealed at one end face and a remaining flow passage is sealed at the other end face. 5. The porous filter according to claim 4, wherein the flow passages that are linearly adjacent to each other are sealed at one end face. 6. The flow passage inner peripheral surface sealed at one end face has a portion where the filtration membrane is not formed, and the flow passage inner peripheral surface sealed at the other end face has a filtration membrane formed therein. The porous filter according to any one of claims 3 to 5, which is provided. 7. The porous filter according to claim 1, wherein the filter is a water purifier filter. 8. A water purifier provided with the porous filter according to claim 1. 9. A porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to the other end face, and a filtration membrane formed on a part of the inner peripheral surface of the flow passages. A porous filter inspection device having: a pressurizing means for pressurizing a predetermined surface of the porous filter with a gas; and a detecting means for detecting gas flowing out from the other surface as bubbles in a liquid. An inspection device for a porous filter, which is characterized in that 10. The inspection device for a porous filter according to claim 9, wherein the predetermined surface is a surface of a porous substrate on which a filtration membrane is not formed. 11. A porous substrate having at least two end faces and a plurality of flow passages communicating from one end face to another end face, and a filtration membrane formed on an inner peripheral surface of a part of the flow passages. A method of inspecting a porous filter having a pressurizing step of pressurizing a predetermined surface of a porous filter with a gas, and detecting bubbles generated by the pressurized gas flowing into a liquid from another surface. A method for inspecting a porous filter, comprising: a detecting step. 12. The method for inspecting a porous filter according to claim 11, wherein the predetermined surface is a surface of a porous substrate on which a filtration membrane is not formed.