JP3538902B2 - Membrane element of immersion type membrane separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a membrane such as a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, and a polymer membrane, and is immersed in a liquid in an immersion tank to perform membrane separation. The present invention relates to a membrane element of a submerged membrane separation device.

[0002]

2. Description of the Related Art An immersion type membrane separation apparatus uses a head difference based on the water depth in an immersion tank in which a membrane element is immersed, and performs membrane separation with a low energy by a suction pump to obtain permeated water. A conventional membrane element immersed in a plurality of such immersion type membrane separation devices is disclosed in, for example, JP-A-1-29310.
As described in Japanese Patent Publication No. 3 (1994), the membranes are attached and suspended so as to sandwich the collecting pipes provided above and below, or the membranes are attached to both sides of the membrane support plate to which the collecting pipes are attached and suspended. Or fixed inside the tank.

[0003]

However, a conventional membrane element in which a membrane is stretched on a rigid membrane support plate,
Since it is heavy, it is difficult to handle and requires a great deal of labor for installation work. In addition, complicated processing such as forming a water collecting groove was required for the membrane support plate. In addition, a membrane element in which a number of membrane leaves having a membrane stretched on both surfaces such as a tricot water collecting cloth is light and easy to handle, but has no rigidity, so that the inside of the immersion tank in which an excessive water flow is generated. When immersed in a membrane, the membrane is degraded due to vibration of the membrane leaf, resulting in a short life of the membrane. Accordingly, an object of the present invention is to provide a membrane element of a immersion type membrane separation device that withstands use in an immersion tank in which an excessive flow of water or bubbles is generated, has high strength, and is easy to handle.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been proposed to achieve the above-mentioned object, and a plurality of barriers are provided at a predetermined interval between two flat plates which are arranged substantially in parallel at an interval. The two flat plates and the barrier are integrated with each other, and a permeate water chamber surrounded by the two flat plates and the barrier is formed. Make up,
A membrane is stretched on the outer surface of the flat plate of the support plate, and a water collecting pipe is provided at an edge of the supporting plate so that the opening of each permeated water chamber communicates with the water collecting pipe.

[0005]

The barrier formed between the flat plates of the support plate functions as a reinforcing material, and the water collecting pipe provided at the edge of the support plate also functions as a reinforcing material. Therefore, the support plate has not only rigidity but also high bending strength in all directions. Then, when this membrane element is immersed in the immersion tank, only water permeates the membrane due to the water pressure of the undiluted solution, and the permeated water flows into the permeated water chamber in the support plate through the permeated water collecting hole of the flat plate. The permeated water flowing into the permeated water chamber enters the collection pipe through the opening and merges with the permeated water from the other permeated water chambers,
Water is drained by the suction action of the water suction pump.

Hereinafter, a reference example will be described with reference to the drawings. FIG. 1 is a perspective view of a membrane element 1 of a submerged membrane separation apparatus as a reference example , and FIG.
FIG. 3 is a sectional view taken along the line Y-Y. The membrane element 1 includes a support plate 3 in which a permeated water chamber 2 is formed in the left-right direction.
A membrane 4 stretched on both sides of the support plate 3;
So that the permeated water chamber 2 of the support plate 3 communicates with the collected water pipe 5 so as to take out permeated water from the permeated water extraction pipe 6 connected to the upper end of the collected water pipe 5. It is composed.

The support plate 3 is a molded product of plastic such as polypropylene. Two flat plates 7 are arranged substantially in parallel at a predetermined interval, and a long barrier 8 in the left and right direction is provided between the two flat plates 7. The two flat plates 7 and the barriers 8 are integrated in parallel at predetermined vertical intervals, and the permeated water chamber 2 extending in the left-right direction surrounded by the flat plates 7 and the upper and lower barriers 8 is vertically moved. A small permeated water collecting hole 9 is formed in the flat plate 7 which is formed in multiple stages and is located between the barriers 8. In addition, both upper edges of the support plate 3 are connected by an upper surface portion, and both lower edges are connected by a lower surface portion, and the upper surface portion and the lower end surface function as uppermost and lowermost barriers 8. Therefore, the support plate 3
The upper and lower end surfaces are sealed by an upper surface and a lower surface, an opening 2 'of the permeated water chamber 2 is opened on the left and right end surfaces, and a permeated water collecting hole 9 is formed in the flat plate 7 on both sides along the permeated water chamber 2. There are many openings.

As described above, since the supporting plate 3 is a plate-like member in which the barrier 8 is provided between the two flat plates 7 to form the permeated water chamber 2, the porosity is high, and therefore, the supporting plate 3 is lightweight, and therefore, is lightweight. Since the barrier 8 also functions as a reinforcing rib, high rigidity can be obtained. In addition, since the barrier 8 is simply molded between the flat plates 7, the molding die is also simple and can be easily manufactured.

In order to stretch the membrane 4 on the outer surface of the flat plate 7 of the support plate 3, the end of the membrane 4 is directly adhered to the surface of the flat plate 7 with an adhesive or welded to the end of the membrane 4. The membrane 4 covers all of the permeated water collecting holes 9 so as not to form a gap between the portion and the surface of the flat plate 7. In the support plate 3 on the side where the end of the permeated water chamber 2 opens, it is desirable to fix the end of the membrane 4 except for the fitting margin with the water collecting pipe 5 described later.

The water collecting pipes 5 are attached to the edges of the support plate 3 where the ends of the barriers 8 intersect, that is, the left and right edges of the support plate 3 in the reference example shown in FIG. The permeated water from each permeated water chamber 2 is joined to communicate with the section 2 ', and in the present embodiment , is constituted by a square pipe having a fitting slit in a longitudinal direction on one side surface. The openings at both ends are closed by a lid member 10, and the permeated water extraction pipe 6 is connected to one end, a hole formed in the upper end lid member 10 in the reference example . In order to attach the water collecting pipe 5 to the support plate 3, the left and right ends of the support plate 3 are fitted into the fitting slits and sealed with the sealant 11. When the water collecting pipes 5 are attached to the left and right ends of the support plate 3 in this manner, the openings 2 ′ of the permeated water chambers 2 formed inside the support plate 3 communicate with the water collecting pipes 5.

As described above, when the water collecting pipes 5 are fitted to both side edges of the support plate 3 in a state perpendicular to the direction in which the plurality of barriers 8 extend substantially in parallel, the water collecting pipes 5 serve as reinforcing members. As a result, the strength of the support plate 3 can be further increased in combination with the barrier 8 functioning as a reinforcing rib.

When the membrane element 1 having the above structure is immersed in an immersion tank containing a stock solution, only water permeates the membrane 4 due to the water pressure of the stock solution, and the permeated water passes through a permeated water collecting hole 9 of the flat plate 7. Then, it flows into the permeated water chamber 2 in the support plate 3. Then, the permeated water flowing into the permeated water chamber 2 flows into the water collecting pipe 5 from the opening 2 ′ by the suction action of the water absorption pump, merges with the permeated water from the other permeated water chamber 2, and forms the permeated water outlet pipe 6.
Is drained through. The plurality of membrane elements 1 immersed in the immersion tank at equal intervals are immersed in a state of being suspended from a drain pipe via a permeated water extraction pipe 6. Therefore,
The permeated water that has passed through the membrane 4 of each membrane element 1 joins at the drainage pipe from the respective water collection pipe 5 via the permeated water extraction pipe 6, and is drained from this drainage pipe.

Further, an aeration tube is arranged near the bottom of the immersion tank, and an aeration air is sent from the aeration tube to generate a rising bubble flow, and the growth of the gel-like substance attached to the film surface is caused by the bubble flow. When deterring, the membrane element 1
Since the peripheral edge of the membrane 4 is directly fixed to the support plate 3 having high rigidity, the support plate 3 does not vibrate due to the bubble flow. Therefore, there is no possibility that the strength of the film 4 is reduced due to the vibration, and the durability of the film 4 can be improved. Then, even when a strong water flow is generated in the immersion tank, the membrane 4 can be similarly supported by the rigid support plate 3 and the strength of the membrane 4 can be prevented from lowering.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The periphery of the film 4 is flat
Sufficient fastening strength can be obtained only by fastening with an adhesive or the like, but the membrane element according to the present invention is
Can be fixed directly to the surface of the flat plate 7 of the support plate 3.
Therefore, the fastening strength can be further increased by fastening other portions.

For example, a first embodiment according to the present invention shown in FIG.
In the embodiment, when the film 4 is attached to the outer surface of the flat plate 7 of the support plate 3, not only the peripheral edge of the film 4 is fixed to the flat plate 7, but also other parts are fixed by the linear fixing portions 12. . Specifically, the film 4 is fixed to the flat plate 7 with a line (adhesion or welding) by a linear fixing portion 12 at a position corresponding to the barrier 8, and a linear fixing portion 12 intersecting with the film 4 is provided. Further, the film 4 is fixed to the flat plate 7. Then, a permeated water collecting hole 9 is opened in a region 13 surrounded by these linear fastening portions 12. In addition, at least one or more permeated water collecting holes 9 may be opened in the area 13 surrounded by the linear fastening portion 12,
A plurality of permeated water collecting holes 9 may be opened in one area 13.

The fastening portion 12 does not necessarily have to be continuous. For example, a second embodiment according to the present invention shown in FIG.
As in the example , the short fastening portions 12 are crossed, the cross fastening portions 12 are provided vertically and horizontally at a predetermined interval, and at least one permeated water flows in a region 13 surrounded by the intersection of the cross fastening portions 12. The water collecting hole 9 may be opened, or as shown in FIG.
As in the third embodiment according to the present invention , the fastening portions 12 are provided in different directions in the form of broken lines, and at least one permeated water collecting portion is formed in the area 13 surrounded by the broken linear fastening portions 12. The hole 9 may be opened. When the non-continuous fastening portion 12 is provided, its length is at least about 10
It is desirable to set it to mm or more.

In this way, in addition to the peripheral edge of the membrane 4, the membrane 4 around the permeated water collecting hole 9 is also fixed directly to the surface of the flat plate 7 of the support plate 3 by the linear fixing portion 12. The fastening strength between the support and the support plate 3 is significantly increased. Therefore, even if the pressure from the permeated water chamber 2 acts on the membrane 4, this pressure is applied to the fixing portion 12.
The film 4 can be prevented from being peeled or broken from the support plate 3. For this reason, for example, when the membrane element 1 is pulled up from the immersion tank and cleaned, the water in the permeated water chamber 2 flows out from the permeated water collecting hole 9 to the outside, and the pressure of the flowing water increases from the inside toward the outside. Even when acting on the film 4, the film 4 is firmly fixed by the fixing portion 12 and does not peel off or break. Further, the drain pipe side, i.e. the water is pumped from the permeate withdrawal pipe 6 side of each membrane element DOO, also be flowing back to the outside of the water from the inside of the membrane 4, distributed pressure of the water flow by fastening section 12 Therefore, the film 4 does not peel off from the support plate 3 or break. Therefore, the flat film 4 be of a type membrane element bets can be backwashed (backwash), to allow cleaning operations good film 4 efficiently.

Further, when the film 4 is directly fixed to the surface of the flat plate 7 of the support plate 3 at a narrow pitch, the vibration of the film 4 caused by the water flow can be efficiently suppressed or absorbed. Therefore, deterioration due to the vibration of the film 4 can be suppressed, and the life of the film 4 can be extended.

In the above-described embodiment, the barrier 8 is formed in the left-right direction and the water collecting pipes 5 are attached to the left and right edges of the support plate 3, but the present invention is not limited to this. A barrier 8 is formed in the up and down direction so that the opening 2 ′ of the permeated water chamber 2 is opened at the upper and lower end surfaces of the support plate 3.
The water collecting pipes 5 may be provided on the upper and lower end surfaces of the water collecting pipes 5 so that the openings 2 ′ of the respective permeated water chambers 2 communicate with the water collecting pipes 5. The shape and number of the permeated water collecting holes 9 formed in the flat plate 7 are not limited, but it is desirable to form a large number of small holes.

[0020]

As described above, according to the present invention, the porosity of the support plate is large, and the weight can be reduced. Therefore, the handling is easy, and the mounting operation can be performed more easily than the conventional membrane element. Also,
Even if it is lightweight, the barrier provided between the flat plates and the water collection pipe provided at the edge of the support plate function as reinforcing materials in different directions,
In addition to having rigidity, high bending strength can be obtained in all directions. And since the permeated water chamber is between the two flat plates of the support plate, it is not necessary to separately provide a spacer such as a water collecting groove or a water collecting cloth, and since a permeated water collecting hole is opened in the flat plate of the support plate, The membrane can be fixed directly to the support plate, and the structure can be simplified. Therefore,
Easy to manufacture. Further, since the membrane can be directly fixed to the support plate having sufficient rigidity, the fixing strength of the membrane to the support plate can be increased as necessary. Therefore, even if a strong water flow is immersed in the immersion tank in which the bubble flow occurs, the support plate does not vibrate, the durability of the film can be increased, and the cleaning operation of the film can be performed efficiently. .

[Brief description of the drawings]

FIG. 1 is a perspective view of a membrane element with a portion of the membrane cut away.

FIG. 2 is a sectional view taken along line XX of the membrane element.

FIG. 3 is a YY cross-sectional view of the membrane element.

FIG. 4 is a partially cutaway perspective view of a support plate.

FIG. 5 is a partially cutaway perspective view showing the inside of the membrane element.

FIG. 6 is an enlarged perspective view of a main part of an embodiment in which the film is fixed by a linear fixing portion.

FIG. 7 is a partial front view of a membrane fastened to a support plate by crossing short linear fastening portions.

FIG. 8 is a partial front view of a film provided with fastening portions in different directions along a broken line and fastened to a support plate.

[Explanation of symbols] 1 Membrane element 2 Permeate water chamber Opening of 2 'permeated water chamber 3 Support plate 4 membrane 5 Water collection pipe 6 Permeate outlet pipe 7 flat plate 8 Barrier 9 Permeate water collecting hole 10 Lid material 11 Sealing material 12 linear fastening parts 13 Area surrounded by linear fastening parts

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 61/00-71/82 C02F 1/44

Claims (1)

(57) [Claims] 1. A plurality of barriers are arranged at a predetermined interval between two flat plates which are arranged substantially in parallel at an interval to integrate the flat plates and the barrier, and are surrounded by the flat plates and the barrier. A permeated water chamber is formed, and a permeated water collecting hole is opened in an opposing flat plate located between the barriers to form a support plate. A membrane is stretched on the outer surface of the flat plate of the support plate, and a support plate is formed. edge to allowed communicating openings provided water collecting pipe each permeate chamber water collecting pipe together with being further membrane is secured to its periphery to a flat plate, the flat plate Toru
A membrane element for a submerged membrane separation device, wherein the membrane element is fixed to the flat plate also around a water collecting hole .