JP2567308B2 - Rotary filtration device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary filtration device,
Specifically, rotary filtration equipment used in chemical industry processes that require harsh corrosion resistance and heat resistance, and pollution control equipment such as water treatment, and in particular, the filtration membrane (filter) is severely clogged and severe. The present invention relates to a rotary filtration device applied to applications requiring cleaning, sterilization and the like.

[0002]

2. Description of the Related Art As a filtration membrane of a conventional filtration device used for this type of application, a separation membrane (organic membrane) made of an organic material or a porous ceramic tube having a pore diameter of 1 μm or more is used only on the inner or outer surface. Separation membranes coated with ceramics having a pore size of 1 μm or less are often used.

In the field of membrane separation technology such as an ultrafiltration process, an inorganic membrane having excellent heat resistance and chemical resistance is known. However, like the conventional organic film, the inorganic film also causes the film to be clogged. Further, although the inorganic film has an advantage that it has a longer life than the organic film, it has many practical problems such as poor moldability and high price, and is not used as much as the organic film.

In particular, when a suspension containing bacterial cells or the like is filtered, the filtration membrane is clogged with the progress of filtration to increase the filtration resistance, and as a result, the filtration efficiency is likely to decrease. A rotary filtration device is a typical one as a filtration device for reducing the increase in filtration resistance due to such clogging as much as possible.

The basic structure of the conventional rotary filtration device is that a rotary shaft having a central hole communicating with the filtrate removing means is provided in a container into which the liquid to be filtered is continuously fed and connected to the driving means. Then, a plurality of disc-shaped filter elements composed of a filter membrane support having a liquid flow passage (a hollow small chamber, etc.) and a filter membrane are fitted concentrically on the rotary shaft with a liquid flowing free space therebetween. The liquid flow passage of the filtration membrane support of the filtration element and the central hole of the rotating shaft are connected so that the liquid can flow.

As such a rotary filtration device, it is possible to prevent clogging of the filtration membrane due to a so-called co-rotation phenomenon (a phenomenon in which the liquid to be filtered accompanies the same direction as the filtration element).
In order to reduce the weight of the filtration element, etc., various improvements have been made mainly from the structural aspect, and various improved rotary filtration devices (structures) have been proposed, but various ones have not been developed yet, and various problems have been encountered. Points remain, and further improvement is desired.

[0007] For example, Japanese Patent Laid-Open No. 47-23949 discloses that a fixed filter element is arranged between a plurality of disc-shaped filter elements, but the structure is very complicated and precise. However, a complicated procedure is required for assembling and disassembling, and clogging of the filtration membrane cannot be sufficiently suppressed. JP-A-1-139114 discloses that a disk-shaped filter element is provided with a plurality of through holes for allowing a liquid to be filtered to flow therethrough in a rotation axis direction, and the accompanying flow of the liquid to be filtered is used to form a gap between the filter elements. It is described that a circulating flow of the liquid to be filtered toward the outer peripheral direction is generated, thereby suppressing clogging of the filtration membrane due to a co-rotation phenomenon, but the heat resistance and chemical resistance of the filtration membrane are not sufficient. Life is short,
Further, a disk-shaped support plate having a complicated structure for supporting the filtration membrane and having a large number of through holes is required, and a sealing portion for fixing the support plate and the filtration membrane and preventing liquid leakage is required. , It has a complicated structure and lacks practicality. Further, as a disc-shaped filter element, a disc-shaped organic porous material obtained by sintering fine particles of a hard synthetic resin such as polypropylene particles having a large number of communicating micropores is coated with a filtration membrane (special feature Japanese Patent Application No. 63-100998), but it is said that this organic porous material is not excellent in heat resistance and chemical resistance, so that the life of the filter element is short and the clogging of the filter membrane cannot be sufficiently suppressed. There are also problems.

[0008]

As described above, various improvements have been attempted in the conventional rotary filtration device.
In any case, it is not possible to sufficiently prevent the clogging of the filtration membrane, and it is difficult to assemble and disassemble, the structure is complicated and the practicability is poor, and the life of the filtration element is not long. There is a point.

The present invention has been made in view of such circumstances, and its purpose is to make use of the characteristics of an inorganic porous material having the advantages of excellent heat resistance and chemical resistance and a long life. Moreover, overcoming problems in terms of processing and cost,
Further, another object of the present invention is to provide a rotary filtration device which is less likely to cause clogging of the filtration membrane and can further promote the practical application of an efficient filtration process.

[0010]

In order to achieve the above object, the rotary filtration device according to the present invention has the following constitution. That is, the rotary filtration device according to claim 1 is provided with a rotary shaft having a central hole communicating with the filtrate extracting means in a container into which the liquid to be filtered is continuously fed and connected to the driving means, A disc-shaped filter membrane support made of an inorganic porous material having a large number of communicating fine pores with a pore size of more than 1 μm is fitted concentrically on the rotary shaft with a liquid flow-free gap, and the support is communicated. While making the fine holes and the central hole of the rotary shaft communicate with each other so that the liquid can flow, a plurality of through-holes for allowing the liquid to be filtered to flow through in the rotary shaft direction are provided in the support, and the surface of the support has a pore diameter of 1 μm or less. The rotary filtration device is characterized in that the filtration film is formed by coating the inorganic porous material.

According to a second aspect of the present invention, in the rotary filtration device, the filtration membrane is an inorganic porous material obtained by applying a mixture containing an organic metal compound-containing solution and an inorganic salt to the surface of a filtration membrane support and firing the mixture. The rotary filtration device according to claim 1. Claim 3
The rotary filtration device according to claim 1, wherein the inner surface of the container into which the liquid to be filtered is fed is lined with glass.
The described rotary filtration device.

[0012]

As described above, the rotary filtration device according to the present invention has through-holes for allowing the liquid to be filtered to flow through the disc-shaped filtration membrane support made of an inorganic porous material having a large number of communicating fine pores having a pore diameter of more than 1 μm. A plurality of them are provided, the surface of the support is coated with an inorganic porous material having a pore size of 1 μm or less to form a filtration membrane, and the communication micropores of the support and the central hole of the rotating shaft are fluidly communicated with each other. ing. Therefore, a disk-shaped filtration element is constituted by the filtration membrane support and the filtration membrane, and when the filtration target is fed into the container while rotating the filtration element, the filtration target is filtered by the filtration membrane, Since the filtrate flows through the communicating fine holes of the filtration membrane support to the central hole of the rotating shaft, continuous filtration operation is possible.

As described above, the disk-shaped filter element is composed of a filter membrane support and a filter membrane, both of which are made of an inorganic porous material, so that they have extremely high heat resistance and chemical resistance as compared with those of an organic material. In addition, the filter membrane itself has a long life, and the filtration membrane itself can sufficiently withstand severe cleaning and sterilization operations as compared with the organic membrane.

Further, a rotary filtration system is basically adopted in which clogging of the filtration membrane hardly occurs. In addition, since the filtration membrane is an asymmetric membrane, a suspension containing bacterial cells and the like is filtered. Even in such a case, clogging is less likely to occur and the amount of permeated liquid can be increased. Further, since the disc-shaped filter element has a through hole for allowing the liquid to be filtered to flow through in the rotation axis direction, the liquid to be filtered is circulated toward the outer circumferential direction in the gap between the filter elements by utilizing the accompanying flow of the liquid to be filtered. Flow can be generated, thereby further reducing clogging of the filtration membrane.

Further, in the disk-shaped filter element, a plurality of through holes are provided in an inorganic porous material such as a disk-shaped grindstone, and the inorganic porous material is used as a filtration film on the surface thereof to dip the material into the raw material liquid. It can be easily formed by coating by the method of. That is, since the shape of the disk-shaped filter element is not complicated,
The moldability of the filtration membrane is not as difficult as that of the conventional inorganic membrane, and the inorganic membrane can be formed relatively easily.

In the present invention, the reason why the pore diameter of the inorganic porous material (inorganic porous membrane) constituting the filtration membrane is set to 1 μm or less is that if it exceeds 1 μm, fine particles pass and the filtration and separation function deteriorates. . The reason why the inorganic porous material constituting the filtration membrane support has communication fine pores is to allow the filtrate to flow into the central hole of the rotary shaft, and the diameter of the communication fine pores exceeds 1 μm. The reason is that if the thickness is 1 μm or less, it becomes difficult for the filtrate to pass through, the flow rate to the central hole of the rotating shaft decreases, and the filtration separation efficiency decreases.

The inorganic porous membrane is formed by applying a mixture containing an organic metal compound-containing solution and an inorganic salt on the surface of a filtration membrane support and firing it, that is, using a sol-gel method. It is desirable to use an inorganic porous film. By using the sol-gel method, it is possible to adjust the pore size of the inorganic porous membrane to 1 μm or less in the simplest and surest way, and it is also excellent in heat resistance and chemical resistance and has good adhesion with the filtration membrane support. This is because an excellent inorganic porous film can be obtained.

That is, the sol-gel method is a method of synthesizing an inorganic material such as glass by heating an organic metal compound-containing solution into a gel through a sol state and then firing it by heating.
It can be synthesized into various shapes such as grains and fibers, and because the composition can be adjusted in a wider range than in the case of ordinary glass manufacturing methods, it is easy to obtain one having excellent heat resistance, strength, and corrosion resistance. It is also characterized in that the porosity (pore size, pore distribution, etc.) of the inorganic material to be synthesized can be adjusted by adding an inorganic salt to the organometallic compound-containing solution. According to this method, the pore size of the inorganic porous membrane can be easily adjusted, and the inorganic porous membrane excellent in heat resistance and chemical resistance can be obtained. Further, since the mixture to be applied to the surface of the filtration membrane support is in a solution state, the pores of the support (porous) can be impregnated immediately after the application, and the impregnation depth can be adjusted. The resulting inorganic porous film has extremely excellent adhesion.

The organometallic compound-containing solution is a solution that always contains an organometallic compound, and alcohol and / or water can be used as the solvent. A typical example of the organometallic compound is a metal alkoxide, but it is not particularly limited. Examples of metal alkoxides include sodium ethoxide, calcium ethoxide, yttrium octylate, and silicon ethoxide.

As described above, since the rotary filtration device according to the present invention has a long service life of the filter element, it is desired to extend the service life of other members accordingly. From this point, it is desired to extend the life of the container into which the liquid to be filtered is fed, and for that purpose, it is effective to improve the heat resistance and the chemical resistance by lining the inner surface of the container with glass.

[0021]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. As shown in FIG. 1, the rotary filtration apparatus according to the first embodiment includes a container 1 having an inlet 5 for a liquid to be filtered (raw water) and an outlet 6 for a circulating flow that flows without being filtered, and the container 1 A rotary shaft 2 which is pierced tightly and inserted into the container and is rotatably supported, and a plurality of disc-shaped filter elements 4 which are concentrically fitted on the rotary shaft 2 at predetermined intervals, and a rotary shaft. A drive device 3 for rotating and driving 2, a suction pump 13 for taking out the filtrate filtered by the filter element 4, a cleaning brush 14 for cleaning the surface of each filter element 4, and a brush for rotating each brush 14. It is composed of a rotating device 15. The above container 1
Is made of metal and has a glass lining on the inner surface of the container, giving it a structure with excellent chemical resistance. The rotary shaft 2 has a central hole 2A that serves as a flow path for the filtrate.

The structure, manufacturing method and fitting of the filter element 4 to the rotary shaft 2 will be described with reference to the enlarged partial sectional view of FIG. Pore diameter: more than 1 μm, for example, a disk-shaped grindstone plate 7 (diameter: 1000 mm, thickness: 10 mm) made of porous alumina having a large number of communicating micropores of 50 μm, a central hole 9 of Φ60 mm, and Φ50 mm around it. Eight through holes 10 are formed. The whole surface of the grindstone plate 7 was coated with an inorganic porous film 8 composed of ultrafine alumina powder having a pore size of 1 μm or less, for example, 0.2 μm. After the coating, the porous film 8 on the inner wall of the central hole 9 is polished and removed to expose the surface of the porous alumina to obtain the disc-shaped filter element 4.

A plurality of Φ5 mm holes 11 are bored at a predetermined interval in a Φ60 mm metal tube to manufacture a rotary shaft 2, and the rotary shaft 2 is provided with the filter element 4, the hole 11 and the central hole 9. It is fitted so that the positions of and match, and fixed with an adhesive. The rotary shaft 2
It is preferred to line the outer surface of the glass with glass.

Fixing with the above-mentioned adhesive was carried out as follows using the sol-gel method. That is, silicon ethoxide: 20gr, ethanol: 20gr, water: 0.1gr, phosphoric acid: 0.
An organometallic compound-containing solution containing 03gr and alumina powder similar to the inorganic porous film 8 are mixed, and the liquid or slurry mixture is applied to and impregnated in the bonding target portion, air-dried and gelled. After heating and drying at 110 ℃, 500
Baked at ° C. Furthermore, after repeating such coating, impregnation and air drying, the gel is dried at 110 ° C and then calcined at 500 ° C.
A strong joint 12 was formed.

(Example 2) After the inorganic porous film 8 of Example 1 was coated, the film 8 was further impregnated with a solution containing an organometallic compound, dried and baked at 500 ° C to form an inorganic porous film. The pore diameter of the membrane 8 was adjusted to 50 nm. Except for this point, the disk-shaped filter element 4 was manufactured by the same method as in Example 1, fitted to the rotary shaft 2 and fixed with an adhesive. As the organometallic compound-containing solution, a mixed solution of silicon tetraethoxide: 10 gr, zirconium propoxide: 2 gr, ethanol: 20 gr, water: 0.1 gr was used.

(Example 3) Instead of the inorganic porous film 8 made of alumina powder of Example 1, an inorganic porous film obtained by applying and firing a mixture containing an organic metal compound-containing solution and an inorganic salt. Except for this point, the disk-shaped filter element 4 was manufactured, fitted to the rotary shaft 2 and fixed in the same manner as in Example 1 to make a rotary filter device. Silicon ethoxide: 20gr, ethanol: 20gr, water: 0.1g in the above mixture.
A solution containing r, phosphoric acid: 0.03 gr was used.

In each of the rotary filtration devices according to Examples 1, 2 and 3 described above, an inorganic membrane (inorganic porous membrane) can be formed relatively easily, and the rotary filtration device can be easily assembled and disassembled. . Further, when a long-term continuous filtration operation was performed using the suspension as a liquid to be filtered, any of the discoidal filtration elements was excellent in heat resistance and chemical resistance of the filtration membrane and the filtration membrane support of its constituent members, It was confirmed that the filter has a long service life and is less likely to cause clogging of the filtration membrane, so that an efficient filtration process can be performed.

[0028]

The rotary filtration device according to the present invention has the above-mentioned structure and functions, and the disk-shaped filter element is composed of a filter membrane support and a filter membrane, both of which are inorganic. As it is made of a porous material, it has excellent heat resistance and chemical resistance compared to those of organic materials, dramatically improving the service life, and the filtration membrane itself is washed more severely than organic membranes.
It becomes possible to sufficiently withstand sterilization work, and even when filtering a suspension containing bacterial cells, clogging is less likely to occur and an efficient filtration process can be carried out. The filtration membrane can be formed relatively easily due to its simple shape, etc., and the rotary filtration device is relatively easy to assemble and disassemble, which is excellent in practicality. The cost is reduced, the economic efficiency is significantly improved, and more efficient and stable long-term continuous rotary filtration operation can be realized.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an outline of a rotary filtration device according to an embodiment of the present invention.

2 is a disk-shaped filter element 4 and a rotary shaft 2 shown in FIG.
FIG.

[Explanation of symbols]

1--container, 2--rotating shaft, 2A--center hole of rotating shaft 2, 3--driving device, 4--disc-shaped filter element, 5--inlet, 6--outlet, 7-- Disc-shaped grindstone plate (filtration membrane support made of inorganic porous material), 8--inorganic porous membrane, 9--center hole of disc-shaped grindstone plate 7, 10--through hole, 11--drilled on rotating shaft Holes, 12--junction, 13--suction pump, 14--cleaning brush, 15--brush rotator,

Claims (3)

(57) [Claims] 1. A rotary shaft having a central hole which communicates with a means for taking out filtrate, is provided in a container into which a liquid to be filtered is continuously fed, and is connected to a driving means. A disk-shaped filter membrane support made of an inorganic porous material having a large number of holes is concentrically fitted on the rotary shaft with a liquid-flowing free space therebetween, and the communication micropores of the support and the rotary shaft are connected. While communicating with the central hole so that the liquid can flow, the support is provided with a plurality of through holes for allowing the liquid to be filtered to flow through in the rotation axis direction, and the surface of the support is coated with an inorganic porous material having a pore diameter of 1 μm or less. A rotary filtration device characterized by being formed by forming a filtration membrane. 2. The rotary filtration according to claim 1, wherein the filtration membrane is an inorganic porous material obtained by applying a mixture containing an organic metal compound-containing solution and an inorganic salt to the surface of a filtration membrane support and firing the mixture. apparatus. 3. The rotary filtration device according to claim 1, wherein the inner surface of the container into which the liquid to be filtered is fed is lined with glass.