JP7590945B2 - Water purification membrane structure - Google Patents

Description

The present invention relates to a water purification membrane structure.

Patent Document 1 discloses a ceramic pervaporation membrane that includes a columnar porous body and a filtration membrane as a water purification membrane structure that produces purified water from raw water.

The columnar porous body has multiple filtration cells that are open on both end faces and to which raw water is supplied, multiple collection cells that are not open on both end faces and in which purified water is collected, and slits that penetrate each collection cell and open to the side. A filtration membrane is formed on the inner surface of each filtration cell. The purified water that permeates the filtration membrane is released to the outside from the side of the porous body and the slits.

International Publication No. 2010/134514

In the ceramic pervaporation membrane described in Patent Document 1, purified water is released from the sides and slits of the porous body, so the entire ceramic pervaporation membrane must be sealed in a watertight casing.

Therefore, when a casing with a sealed ceramic pervaporation membrane is actually installed, the filtration cell area per unit floor area becomes small due to the large size of the casing.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a water purification membrane structure that can increase the filtration cell area per unit floor area.

The water purification membrane structure according to the present invention is a water purification membrane structure that produces purified water from raw water, and includes a porous body and a seal. The porous body is a columnar body having a first end face, a second end face opposite to the first end face, and a side face connected to the first end face and the second end face, and has multiple filtration cells to which raw water is supplied and a water collection hole through which purified water is collected inside. The seal has a first end face seal covering the first end face, a second end face seal covering the second end face, and a side face seal covering the side face, and is made of a water-impermeable material. The multiple filtration cells penetrate the porous body from the first end face to the second end face and open into the first end face seal and the second end face seal, respectively. The water collection hole penetrates the porous body from the first end face to the second end face and opens into the first end face seal.

The present invention provides a water purification membrane structure that can increase the filtration cell area per unit floor area.

FIG. 1 is a perspective view of a water purification membrane structure. FIG. 2 is a perspective view of the water purification membrane structure. FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. 4 is a cross-sectional view taken along line BB of FIG. FIG. 5 is a cross-sectional view taken along the line CC of FIG. FIG. 6 is a vertical cross-sectional view of the water purification membrane structure. FIG. 7 is a cross-sectional view of the water purification membrane structure. FIG. 8 is an enlarged view of an area AR in FIG. FIG. 9 is a schematic diagram for explaining a method for producing a water purification membrane structure. FIG. 10 is a cross-sectional view of an extruder.

(Configuration of water purification membrane structure 1)
The configuration of the water purification membrane structure 1 will be described with reference to the drawings.

Figures 1 and 2 are perspective views of the water purification membrane structure 1. Figure 3 is a cross-sectional view taken along line A-A in Figure 1. Figure 4 is a cross-sectional view taken along line B-B in Figure 1. Figure 5 is a cross-sectional view taken along line C-C in Figure 1. Figure 6 is a cross-sectional view of the water purification membrane structure 1 partially cut vertically. Figure 7 is a cross-sectional view of the water purification membrane structure 1 partially cut horizontally.

The water purification membrane structure 1 is used to produce purified water from raw water. The water purification membrane structure 1 is used while immersed in a storage tank in which raw water is stored.

The water purification membrane structure 1 has a monolith structure. A monolith structure refers to a structure having multiple cells that run through in the longitudinal direction, and is a concept that includes a honeycomb structure.

The water purification membrane structure 1 comprises a columnar porous body 10 and a seal 20.

1. Porous body 10
The porous body 10 according to this embodiment is a cylinder extending in the longitudinal direction. The external shape of the porous body 10 is not particularly limited, and may be, for example, an elliptical cylinder, a polygonal cylinder, a rectangular parallelepiped, or a square. The size of the porous body 10 is not particularly limited, and may be, for example, a length of 100 to 1500 mm and a diameter of 10 to 200 mm.

As shown in Figures 1 and 2, the porous body 10 has a first end face S1, a second end face S2, and a side face S3. The second end face S2 is provided on the opposite side of the first end face S1. The side face S3 is connected to the first end face S1 and the second end face S2. The outer edge of one end of the side face S3 is connected to the outer edge of the first end face S1. The outer edge of the other end of the side face S3 is connected to the outer edge of the second end face S2.

As shown in Figures 1 to 6, the porous body 10 has a plurality of filtration cells 11, a plurality of water collection cells 12, a plurality of first water collection slits 13, a plurality of second water collection slits 14, and a water collection hole 15 therein.

As shown in FIG. 6, each filtration cell 11 penetrates the porous body 10 from the first end face S1 to the second end face S2. Each filtration cell 11 extends in the longitudinal direction of the porous body 10. Both ends of each filtration cell 11 open to a first end face seal 21 and a second end face seal 22, which will be described later, of the seal 20. Thus, each filtration cell 11 opens to both end faces of the water purification membrane structure 1. Raw water is supplied to each filtration cell 11 from the opening on the first end face seal 21 side and the opening on the second end face seal 22 side.

As shown in Figures 3 to 5, the cross section of each filtration cell 11 according to this embodiment is circular. The cross-sectional shape of each filtration cell 11 is not particularly limited and may be, for example, elliptical or polygonal. The inner diameter (circumscribed circle diameter) of each filtration cell 11 is not particularly limited and may be, for example, 1.0 mm or more and 3.0 mm or less. The number and positions of the filtration cells 11 can be set as appropriate.

As shown in Figures 5 and 6, each water collection cell 12 is provided inside the porous body 10. Each water collection cell 12 extends in the longitudinal direction of the porous body 10. As shown in Figure 6, both ends of each water collection cell 12 communicate with first and second water collection slits 13, 14 inside the porous body 10. Purified water that has permeated the porous body 10 is collected in each water collection cell 12.

As shown in FIG. 5, the cross section of each water collection cell 12 in this embodiment is circular. The cross-sectional shape of each water collection cell 12 is not particularly limited and may be, for example, elliptical or polygonal. The inner diameter (circumscribed circle diameter) of each water collection cell 12 is not particularly limited and may be, for example, 0.5 mm or more and 3.0 mm or less. The number and position of the water collection cells 12 can be set appropriately.

The first water collection slits 13 collect purified water from the water collection cells 12. A plurality of first water collection slits 13 are provided to collect purified water evenly from the water collection cells 12. As shown in FIG. 3 and FIG. 6, each first water collection slit 13 is provided inside the end of the porous body 10 on the first end face S1 side. Each first water collection slit 13 extends in the short direction perpendicular to the longitudinal direction of the porous body 10. The outer edge of each first water collection slit 13 is sealed by a first plugging portion 13a. The outer surface of the first plugging portion 13a is covered by a first end face seal 21 of the seal 20, which will be described later. Each first water collection slit 13 penetrates one or more water collection cells 12.

As shown in FIG. 3, the plurality of first water collection slits 13 include ten first communication slits 131 and six first non-communicating slits 132. As shown in FIG. 6 and FIG. 7, each first communication slit 131 directly communicates with the water collection hole 15. Each first communication slit 131 opens into the water collection hole 15. Each first non-communicating slit 132 does not directly communicate with the water collection hole 15. Each first non-communicating slit 132 directly communicates with one or more first communication slits 131. Each first non-communicating slit 132 indirectly communicates with the water collection hole 15 via one or more first communication slits 131.

The length of each first water collection slit 13 in the longitudinal direction is not particularly limited, but can be, for example, 1% to 20% of the total length of the porous body 10. The number and positions of the first water collection slits 13 can be set appropriately according to the number and positions of the water collection cells 12.

The second water collection slits 14 collect purified water from the collection cells 12. A plurality of second water collection slits 14 are provided to collect purified water evenly from the collection cells 12. As shown in FIG. 4 and FIG. 6, each second water collection slit 14 is provided inside the end of the porous body 10 on the second end face S2 side. Each second water collection slit 14 extends in the short direction of the porous body 10. The outer edge of each second water collection slit 14 is sealed by a second plugging portion 14a. The outer surface of the second plugging portion 14a is covered by a second end face seal 22 of the seal 20, which will be described later. Each second water collection slit 14 penetrates one or more collection cells 12. Each second water collection slit 14 collects purified water from each collection cell 12.

As shown in FIG. 4, the plurality of second water collection slits 14 include ten second communication slits 141 and six second non-communicating slits 142. As shown in FIG. 6, each second communication slit 141 directly communicates with the water collection hole 15. Each second communication slit 141 opens into the water collection hole 15. Each second non-communicating slit 142 does not directly communicate with the water collection hole 15. Each second non-communicating slit 142 directly communicates with one or more second communication slits 141. Each second non-communicating slit 142 indirectly communicates with the water collection hole 15 via one or more second communication slits 141.

The length of each second water collection slit 14 in the longitudinal direction is not particularly limited, but can be, for example, 1% to 20% of the total length of the porous body 10. The number and positions of the second water collection slits 14 can be set appropriately according to the number and positions of the water collection cells 12.

As shown in FIG. 6, the water collection hole 15 is a bottomed recess that opens into the first end seal 21. The water collection hole 15 extends in the longitudinal direction inside the porous body 10. The second end face S2 side of the water collection hole 15 is sealed by a packing 15a. Therefore, in this embodiment, the bottom of the water collection hole 15 is formed by the packing 15a. In this manner, the water collection hole 15 opens only on one end face side of the water purification membrane structure 1. An O-ring (not shown) for connecting a purified water discharge pipe (not shown) is attached to the opening of the water collection hole 15 formed in the first end seal 21. The outer edge of the opening of the water collection hole 15 is preferably chamfered. This makes it easier to attach the O-ring and prevents the outer edge of the opening from being chipped when the O-ring is attached.

When the first end face seal 21 of the seal 20 is viewed in plan, the water collection hole 15 is located at the center of the first end face S1 of the porous body 10. The water collection hole 15 is formed along the axis of the porous body 10. A plurality of filtration cells 11 are arranged around the water collection hole 15.

The cross section of the water collection hole 15 in this embodiment is circular. The cross-sectional shape of the water collection hole 15 is not particularly limited and may be, for example, elliptical or polygonal. The inner diameter (circumscribed circle diameter) of the water collection hole 15 is not particularly limited and may be, for example, 15% to 45% of the outer diameter (circumscribed circle diameter) of the porous body 10.

As shown in FIG. 6, the first communication slits 131 and the second communication slits 141 are opened on the inner peripheral surface of the water collection hole 15. The water collection hole 15 collects purified water from each of the first communication slits 131 and each of the second communication slits 141. The purified water collected in the water collection hole 15 is discharged to the outside through the purified water discharge pipe.

Here, FIG. 8 is an enlarged view of region AR in FIG. 7. As shown in FIG. 8, the porous body 10 has a substrate 31 and a filtration layer 32.

The substrate 31 is the main body of the porous body 10. The substrate 31 has the above-mentioned water collection cells 12, first water collection slits 13, second water collection slits 14, and water collection holes 15 formed therein.

The substrate 31 is made of a porous material. The substrate 31 contains aggregate and a binder.

Alumina, silicon carbide, titania, mullite, cerium oxide, cordierite, and the like can be used as aggregates. The binder is an inorganic oxide material that melts at a lower temperature than the aggregate components and bonds the aggregates together. The aggregate content in the base material 31 is not particularly limited, but can be, for example, 80% by volume or more and 99% by volume or less, and preferably 85% by volume or more and 95% by volume or less.

The binder may be an alumina or silica-based inorganic oxide material containing an alkali metal or alkaline earth metal. As the alkali metal, at least one of sodium (Na), potassium (K) and lithium (Li) may be used. The alkali metal may exist in the form of an oxide. As the alkaline earth metal, at least one of magnesium (Mg), calcium (Ca), strontium (Sr) and barium (Ba) may be used. The alkaline earth metal may exist in the form of an oxide. It is preferable that the binder contains both an alkali metal and an alkaline earth metal. The content of the binder in the base material 31 is not particularly limited, but may be, for example, 1% by volume to 20% by volume, and preferably 5% by volume to 15% by volume.

The porosity of the substrate 31 is not particularly limited, but can be, for example, 25% to 50%, and preferably 30% to 45%. The porosity of the substrate 31 can be measured by mercury intrusion porosimetry. The average pore size of the substrate 31 is not particularly limited, but can be, for example, 0.1 μm to 50 μm, and preferably 1 μm to 10 μm from the viewpoint of improving the film-forming properties of the filtration layer 32.

The filtration layer 32 is formed in a cylindrical shape. The space inside the filtration layer 32 is the filtration cell 11 described above.

In this embodiment, the filtration layer 32 has a first filtration layer 32a and a second filtration layer 32b.

The first filtration layer 32a is formed on the inner surface of the substrate 31. The first filtration layer 32a can be made of the above-mentioned porous material that can be used for the substrate 31. The average pore diameter of the first filtration layer 32a may be smaller than the average pore diameter of the substrate 31, and can be, for example, 0.005 μm or more and 5 μm or less. The average pore diameter of the first filtration layer 32a can be measured by a perm porometer. The porosity of the first filtration layer 32a is not particularly limited, but can be, for example, 20% or more and 60% or less. The thickness of the first filtration layer 32a is not particularly limited, but can be, for example, 1 μm or more and 300 μm or less.

The second filtration layer 32b is formed on the inner surface of the first filtration layer 32a. The second filtration layer 32b can be made of the above-mentioned porous material that can be used for the base material 31. The average pore diameter of the second filtration layer 32b may be smaller than the average pore diameter of the first filtration layer 32a, and can be, for example, 0.001 μm or more and 2 μm or less. The average pore diameter of the second filtration layer 32b can be measured by a perm porometer. The porosity of the second filtration layer 32b is not particularly limited, but can be, for example, 20% or more and 60% or less. The thickness of the second filtration layer 32b is not particularly limited, but can be, for example, 1 μm or more and 50 μm or less.

2. Seal 20
The seal 20 covers almost the entire surface of the porous body 10 except for the openings of each filtration cell 11 and the water collection holes 15. The seal 20 is made of a water-impermeable material. Examples of the water-impermeable material that can be used include glass, resin, metal, and rubber. Considering compatibility with the thermal expansion coefficient of the porous body 10, glass is preferable as the water-impermeable material.

As shown in Figures 1 and 2, the seal 20 in this embodiment has a first end face seal 21, a second end face seal 22, and a side seal 23.

The first end seal 21 covers the first end surface S1 of the porous body 10. However, the first end seal 21 does not cover the filtration cells 11 and the water collection holes 15, and as described above, the filtration cells 11 and the water collection holes 15 are open to the first end seal 21.

The second end seal 22 covers the second end surface S2 of the porous body 10. However, the second end seal 22 does not block the filtration cells 11 and the water collection holes 15, and as described above, the filtration cells 11 and the water collection holes 15 are open to the second end seal 22.

The side seal 23 covers the side S3 of the porous body 10. No openings are formed in the side seal 23.

By covering the entire surface of the porous body 10 with the seal 20 in this way, a configuration is realized in which raw water is supplied to the inside only from each filtration cell 11, and purified water is discharged only from the water collection hole 15.

(Method for manufacturing water purification membrane structure 1)
Next, a method for manufacturing the water purification membrane structure 1 will be described with reference to the drawings.

Figure 9 is a schematic diagram for explaining the manufacturing method of the water purification membrane structure 1.

The manufacturing method of the water purification membrane structure 1 includes a porous body forming process for forming the porous body 10 and a seal forming process for forming the seal 20. Each process will be described below.

1. Porous Body Forming Step (1) Extrusion Molding Step First, a porous material for the substrate 31 is prepared and charged into the extrusion molding machine 50 .

Next, the porous material is extruded by the extrusion molding machine 50 to extrude a columnar base material molding 31X. The base material molding 31X has a plurality of filtration cell through holes (not shown) for forming a plurality of filtration cells 11, a plurality of water collection cell through holes (not shown) for forming a plurality of water collection cells 12, and a water collection hole through hole 15X.

Figure 10 is a cross-sectional view of an extrusion molding machine 50. The extrusion molding machine 50 has a case 51, a material storage space 52, a nozzle 53, and a pressing plate 54. The material storage space 52 is provided inside the case 51. The material storage space 52 stores a porous material. The nozzle 53 is disposed inside the case 51. Inside the nozzle 53, slits are formed corresponding to the patterns of the through holes for the water collection cells and the through holes for the water collection holes 15X. A recess 53a is formed on the front surface of the nozzle 53. The recess 53a accommodates a fixing plate 53b. The fixing plate 53b is a member for fixing the nozzle 53. The pressing plate 54 is an annular member in which an opening is formed to determine the cross-sectional shape and dimensions of the base material molded body 31X.

Here, the bottom surface 53R of the recess 53a formed in the nozzle 53 includes an abutment surface r1 and an annular surface r2. The abutment surface r1 is the area of the bottom surface 53R that abuts against the fixed plate 53b. The annular surface r2 is an annular area that corresponds to the inner wall of the water collection hole 15. It is preferable that the annular surface r2 is generally flat. Although the reason is unclear, by making the annular surface r2 flat, it is possible to suppress the occurrence of cracks in the inner wall of the water collection hole 15 compared to when the annular surface r2 is an inclined surface.

(2) Drying step: The substrate molded body 31X is dried. The substrate molded body 31X may be dried by forcibly blowing hot air onto the substrate molded body 31X placed on a table, or may be dried naturally on the table.

After drying the base material molded body 31X, the length of the base material molded body 31X may be adjusted as appropriate by cutting both ends of the base material molded body 31X as appropriate.

(3) Primary Slit Forming Process A plurality of primary slits 13X penetrating the respective water collection cell through holes are formed in a first end face of the base material molding 31X. Then, a plurality of primary slits 14X (not shown) penetrating the respective water collection cell through holes are formed in a second end face of the base material molding 31X.

Each primary slit 13X will eventually become part of each first water collection slit 13, and each primary slit 14X will eventually become part of each second water collection slit 14.

There are no particular limitations on the depth of each of the primary slits 13X, 14X, but if they are too deep, deformation is likely to occur at both ends of the base molded body 31X, and if they are too shallow, the benefit of forming the primary slits in advance is diminished, so it is preferable to adjust the depth within a range that achieves both of these.

(4) Temporary Filling Process Each primary slit 13X is temporarily filled by forcing a temporary filling material into each primary slit 13X from the first end face side of the base material molded body 31X to a predetermined depth. Then, each primary slit 14X is temporarily filled to a predetermined depth by forcing a temporary filling material into each primary slit 14X from the second end face side of the base material molded body 31X to a predetermined depth. The porous material for the base material 31 can be used as the temporary filling material.

When pushing in the temporary filler material, it is preferable to push in the temporary filler material with stoppers 57 inserted into each of the primary slits 13X and 14X. This allows the temporary filler material to be filled to a specified depth with the desired density.

(5) Substrate Firing Step The substrate molded body 31X is fired under predetermined conditions (for example, 800° C. to 1500° C., 10 hours to 200 hours) to form the substrate 31.

(6) Filtration layer forming step A slurry for the first filtration layer 32a is prepared by mixing a porous material for the first filtration layer 32a with water. Next, the slurry for the first filtration layer is pumped into each filtration cell through hole of the substrate 31 under a negative pressure environment to form a first filtration layer molded body on the inner surface of each filtration cell through hole. Then, the substrate 31 on which the first filtration layer molded body is formed is fired under predetermined conditions (e.g., 800°C to 1500°C, 10 hours to 200 hours) to form the first filtration layer 32a.

Next, the porous material for the second filtration layer 32b is mixed with water to prepare a slurry for the second filtration layer. The slurry for the second filtration layer is then pumped to the inside of the first filtration layer 32a under a negative pressure environment to form a second filtration layer body on the surface of the first filtration layer 32a. The substrate 31 on which the second filtration layer body is formed is then fired under predetermined conditions (e.g., 800°C to 1500°C, 10 hours to 200 hours) to form the second filtration layer 32b.

(7) Secondary Slit Forming Process A cutting tool is used to further cut each primary slit 13X from the first end face side of the substrate 31, thereby forming a plurality of secondary slits 13Y. Then, a cutting tool is used to further cut each primary slit 14X from the second end face side of the substrate 31, thereby forming a plurality of secondary slits 14Y (not shown). As a result, a plurality of water collecting cells 12 are formed inside the substrate 31.

In this process, the temporary filler material filled in each of the primary slits 13X, 14X is removed. Because each of the primary slits 13X, 14X is formed in advance, each of the secondary slits 13Y, 14Y can be formed relatively easily, and the tool life is also extended.

(8) Main sealing step Each secondary slit 13Y is sealed by pushing a main sealing material into a portion of each secondary slit 13Y that opens to the outer surface of the base material 31. In this way, a plurality of first water collecting slits 13 are formed inside the base material 31.

Next, the secondary slits 14Y are sealed by pushing the weatherstripping material into the portions of the secondary slits 14Y that open to the outer surface of the base material 31. This forms multiple second water collection slits 14 inside the base material 31.

The porous material for the base material 31 can be used as the filler material.

The porous body 10 is completed through the above steps.

2. Seal Forming Step (1) End Face Seal Forming Step A water-impermeable material is applied or printed on the first end face S1 of the porous body 10 to form a first end face seal body 21X.

Next, a non-permeable material is applied or printed on the second end surface S2 of the porous body 10 to form the second end surface seal molding 22X.

(2) Side Seal Forming Step A water-impermeable material is applied or printed on the side surface S3 of the porous body 10 to form a side seal molding 23X.

In this process, it is preferable to insert the support member 56 into the through hole 15X for the water collection hole of the porous body 10 and hang the porous body 10 while applying or printing the non-permeable material. This allows the side seal molding 23X to be formed uniformly all over.

(3) Seal Firing Step Finally, the porous body 10 on which the seal bodies 21X, 22X, and 23X are formed is sintered under predetermined conditions (e.g., 800°C to 1500°C, 10 hours to 200 hours). Thereafter, the second end surface S2 side of the through hole 15X for water collection hole is sealed with a packing 15a, thereby completing the water purification membrane structure 1.

(Features)
(1) The water purification membrane structure 1 includes a porous body 10 and a seal 20. The porous body 10 has a plurality of filtration cells 11 to which raw water is supplied, and water collection holes 15 through which purified water is collected. The seal 20 covers substantially the entire surface of the porous body 10 except for the filtration cells 11 and the water collection holes 15. The seal 20 is made of a water-impermeable material.

In this way, since the seal 20 covers the entire surface of the porous body 10, raw water can be supplied to the inside only from each filtration cell 11, and purified water can be discharged only from the water collection hole 15. Therefore, since there is no need to separately seal the water purification membrane structure 1 in a watertight casing, when the water purification membrane structure 1 is installed in a water tank, for example, the filtration cell area per unit floor area can be increased compared to when a casing is required.

(2) When the first end face seal 21 of the seal 20 is viewed in plan, the water collection hole 15 is located at the center of the first end face S1 of the porous body 10, and each filtration cell 11 is located around the water collection hole 15. Therefore, water can be efficiently collected from each filtration cell 11 using a single water collection hole 15, thereby improving the water purification efficiency of the water purification membrane structure 1.

(3) The porous body 10 has a plurality of water collection cells 12 in which purified water is collected, and a plurality of first water collection slits 13 penetrating the plurality of water collection cells 12. Therefore, water can be efficiently collected from each water collection cell 12, and the water purification efficiency of the water purification membrane structure 1 can be improved.

(4) The multiple first water collection slits 13 include a first communication slit 131 that directly communicates with the water collection hole 15. This allows water to be efficiently collected from each water collection cell 12 to the water collection hole 15 via the first communication slit 131, thereby improving the water purification efficiency of the water purification membrane structure 1.

(5) The multiple first water collection slits 13 include a first non-communicating slit 132 that does not directly communicate with the water collection hole 15. The first non-communicating slit 132 directly communicates with the first communicating slit 131. Therefore, water can be efficiently collected from the first non-communicating slit 132 to the water collection hole 15 via the first communicating slit 131, thereby improving the water purification efficiency of the water purification membrane structure 1.

(Modification of the embodiment)
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[Modification 1]
In the above embodiment, the configuration of the water purification membrane structure 1 has been described with reference to Figures 1 to 7, but the detailed configuration of the water purification membrane structure 1 can be changed as appropriate. The water purification membrane structure 1 only needs to include a porous body 10 having filtration cells 11 and water collection holes 15, and a seal 20 that covers the surface of the porous body 10. Therefore, the water purification membrane structure 1 does not need to include the water collection cells 12, the first water collection slits 13, and the second water collection slits 14. It is also sufficient that one or more filtration cells 11 and one or more water collection holes 15 are provided.

[Modification 2]
In the above embodiment, the second end surface S2 side of the water collection hole 15 is sealed by the packing 15a, but the method of sealing the second end surface S2 side of the water collection hole 15 is not particularly limited.

[Modification 3]
In the above embodiment, the primary slits 13X, 14X are formed for all the through holes for the water collection cells in the primary slit forming step, and the primary slits 13X, 14X are temporarily filled in the temporary filling step, but this is not limited to the above. If there is a concern that the strength of the base molded body 31X will be reduced by forming the primary slits 13X, 14X for all the through holes for the water collection cells, the primary slits 13X, 14X may be formed for some of the through holes for the water collection cells in the primary slit forming step. In this case, the remaining through holes for the water collection cells remain open, so in the filtration layer forming step, it is necessary to block the openings of the through holes for the water collection cells as needed using an organic material that evaporates by firing.

[Modification 4]
In the above embodiment, the filtration layer 32 includes the first filtration layer 32a and the second filtration layer 32b, but is not limited thereto. The filtration layer 32 may include only one of the first filtration layer 32a and the second filtration layer 32b, or may further include one or more filtration layers in addition to the first filtration layer 32a and the second filtration layer 32b.

1 Water purification membrane structure 10 Porous body S1 First end surface S2 Second end surface S3 Side surface 11 Filtration cell 12 Water collection cell 13 First water collection slit 14 Second water collection slit 15 Water collection hole 20 Seal 21 First end surface seal 22 Second end surface seal 23 Side seal 31 Substrate 32 Filtration layer 32a First filtration layer 32b Second filtration layer 50 Extruder 51 Case 53 Base 53 Abutment surface 53b Fixing plate 53R Bottom surface r1 Contact surface r2 Annular surface 56 Support member

Claims (4)

A water purification membrane structure for producing purified water from raw water,
A porous body having a first end surface, a second end surface opposite to the first end surface, and a side surface connected to the first end surface and the second end surface, the porous body having therein a plurality of filtration cells to which the raw water is supplied and a water collection hole through which the purified water is collected;
a seal including a first end seal covering the first end surface, a second end seal covering the second end surface, and a side seal covering the side surface;
Equipped with
The plurality of filtration cells extend through the porous body from the first end surface to the second end surface and open to the first end surface seal and the second end surface seal,
the water collection hole is a bottomed recess that opens to the first end face seal,
the first end seal, the second end seal, and the side seal are each made of a water-impermeable material;
The porous body includes a plurality of water collection cells in which the purified water is collected, and a plurality of first communication slits each communicating with one end of the plurality of water collection cells and extending radially from the water collection hole.
Water purification membrane structure. In a cross section along a short direction perpendicular to the longitudinal direction of the porous body, the plurality of first communicating slits include four first communicating slits arranged in an X-shape with the water collection hole as a center.
The water purification membrane structure according to claim 1. The porous body includes a plurality of second communication slits each communicating with the other end of each of the plurality of water collecting cells and extending radially from the water collecting hole.
The water purification membrane structure according to claim 1. In a cross section along a short direction perpendicular to the longitudinal direction of the porous body, the plurality of second communication slits include four second communication slits arranged in an X-shape with the water collection hole as a center.
The water purification membrane structure according to claim 3.

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