JP2019188275A - Filtering device - Google Patents

Abstract

To provide a filtering device that can efficiently remove a suspended matter adhering to a hollow fiber membrane by air bubble.SOLUTION: The filtering device according to one embodiment of the invention comprises: a plurality of filtering modules having a plurality of hollow fiber membranes aligned vertically and a pair of holding members which fix upper and lower ends of the plurality of hollow fiber membranes; a support body that parallely holds the plurality of filtering modules in parallel and at equal intervals; and one or a plurality of aeration modules which supply air bubble from below the filtering modules. The hollow fiber membrane is composed mainly of polytetrafluoroethylene. When an average interval between the pair of holding members in the filtering module is defined as A, an average interval between holding regions for the hollow fiber membrane in the adjacent filtering modules is defined as B, and an average effective length of the hollow fiber membrane exposed between the pair of holding members at the time when the membrane is moistened is defined as C, a value determined from a formula of (C-A)/2B is 10 or more and 20 or less.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a filtration device.

  For example, in wastewater treatment or the like, a liquid may be filtered using a filtration membrane. In order to perform such filtration, a plurality of hollow fiber membranes are aligned in one direction, both ends of the plurality of hollow fiber membranes are held by a pair of holding members, and a plurality of hollow fibers are held in one or both holding members. An immersion type filtration module provided with a flow path communicating with the lumen of the thread membrane is used. Such a filtration module is immersed in the liquid to be treated stored in the water tank, and sucks the filtered liquid that has permeated the hollow fiber membrane and entered the lumen of the hollow fiber membrane through the flow path of the holding member. It is used to construct a filtration system that takes out to the outside.

  JP 2013-56346 A discloses a filtration module using a hollow fiber membrane formed from polytetrafluoroethylene (PTFE). In the above publication, by supplying air bubbles from below to a plurality of hollow fiber membranes that are aligned vertically, the hollow fiber membranes are shaken, thereby obtaining the effect of removing the suspended components adhering to the outer peripheral surface of the hollow fiber membranes. It is described.

JP 2013-56346 A

  As disclosed in the above publication, in order to shake the hollow fiber membrane greatly by bubbles, it is necessary that the length of the hollow fiber membrane has some margin, that is, the hollow fiber membrane has a slack. However, if the hollow fiber membranes are greatly loosened, the hollow fiber membranes may be entangled with each other, which may promote the obstruction due to turbidity.

  This invention is made | formed based on the above situations, and makes it a subject to provide the filtration apparatus which can remove efficiently the turbidity adhering to the hollow fiber membrane by the bubble.

The filtration device according to one aspect of the present invention made to solve the above problems includes a plurality of hollow fiber membranes that are aligned vertically and a pair of holding members that fix the upper and lower ends of the plurality of hollow fiber membranes. A filtration device comprising a plurality of filtration modules, a support for holding the plurality of filtration modules in parallel at equal intervals, and one or a plurality of air supply modules for supplying air bubbles from below the filtration modules. The main component of the hollow fiber membrane is polytetrafluoroethylene, the average distance between the pair of holding members in the filtration module is A, the average distance between the holding regions of the hollow fiber membranes of the adjacent filtration modules is B, The average effective length when the hollow fiber membrane exposed between the pair of holding members is wet is C, and the value of (C ² -A ² ) ^0.5 / 2B is 10 or more and 18 or less.

  The filtration device according to one embodiment of the present invention can efficiently remove turbidity attached to the hollow fiber membrane by air bubbles.

FIG. 1 is a schematic diagram showing a filtration system having a filtration device according to an embodiment of the present invention. FIG. 2 is a schematic perspective view showing the filtration module and the cleaning module that are held by the filtration device of FIG. 1. 3 is a schematic horizontal cross-sectional view of the filtration module of FIG. FIG. 4 is a schematic view showing the relationship between the hollow fiber membrane and the holding member of the filtration module in the filtration device of FIG. FIG. 5 is a schematic vertical cross-sectional view of the filtration module of FIG.

[Description of Embodiment of the Present Invention]
A filtration apparatus according to an aspect of the present invention includes a plurality of filtration modules having a plurality of hollow fiber membranes arranged vertically and a pair of holding members that fix upper and lower ends of the plurality of hollow fiber membranes, and the plurality of filtration modules. A filtration apparatus comprising a support for holding the filtration modules in parallel at equal intervals and one or a plurality of air supply modules for supplying bubbles from below the filtration module, wherein the main component of the hollow fiber membrane is It is polytetrafluoroethylene, and the average distance between the pair of holding members in the filtration module is A, the average distance between the holding regions of the hollow fiber membranes of the adjacent filtration modules is exposed between the pair of holding members. The average effective length when the hollow fiber membrane is wet is C, and the value of (C ² -A ² ) ^0.5 / 2B is 10 or more and 20 or less.

The filtration device can swing the hollow fiber membrane by bubbles supplied from the air supply module by setting the value of (C ² -A ² ) ^0.5 / 2B within the above range, and The hollow fiber membranes are not easily entangled with each other. For this reason, the said filtration apparatus can remove efficiently the turbidity adhering to the hollow fiber membrane by the bubble.

  In the filtration apparatus, it is preferable that an average effective length when the hollow fiber membrane exposed between the pair of holding members is dried is larger than an average interval A in the vertical direction of the pair of holding members. Thus, when the average effective length at the time of drying of the hollow fiber membrane exposed between the pair of holding members is larger than the average interval between the pair of holding members, the filtration module is not used. It is possible to prevent the hollow fiber membrane from being damaged due to unnecessary tension acting.

  In the filtering device, it is preferable that an average interval A in the vertical direction of the pair of holding members is 2.0 m or more and 4.0 m or less. Thus, when the average distance A in the vertical direction of the pair of holding members is within the above range, the conventional filter device is likely to be entangled with the hollow fiber membrane, and thus the advantage of applying the present invention is remarkable. Become.

  In the filtering device, it is preferable that an average interval B between the holding regions is 15 mm or more and 50 mm or less. As described above, when the average interval B between the holding regions is within the above range, the hollow fiber membranes are more reliably prevented from being entangled, and the number of the hollow fiber membranes per volume is increased to perform filtration. Ability can be improved.

  In the filtration device, the hollow fiber membrane preferably has an average outer diameter of 1.5 mm or greater and 4.0 mm or less. Thus, when the average outer diameter of the hollow fiber membrane is within the above range, the number of the hollow fiber membranes per volume can be further increased to further improve the filtration capacity.

  Here, “when wet” means a state immersed in water for 2 weeks or more, and “when dry” means a state left in the atmosphere for 2 weeks or more.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The filtration system of FIG. 1 includes a filtration tank W that stores a liquid to be treated and a filtration device 1 according to an embodiment of the present invention that is disposed in the filtration tank W. In the following description, in FIG. 1, the vertical direction is the Z direction, the horizontal direction is the X direction, and the depth direction on the paper is the Y direction.

[Filtration tank]
The filtration tank W stores the liquid to be processed so that the filtration device 1 is immersed therein.

  As a material of the filtration tank W, for example, resin, metal, concrete, or the like can be used.

[Filtering equipment]
The filtration device 1 includes a plurality of filtration modules 2, a support 3 that holds the plurality of filtration modules 2 in parallel and at equal intervals, an air supply module 4 that supplies air bubbles G from below the filtration module 2, A discharge mechanism 5 that discharges the processed liquid obtained by filtering the liquid to be processed by the plurality of filtration modules 2 from the air supply module 4 is provided.

[Filtration module]
As shown in FIGS. 1 and 2, the filtration module 2 includes a plurality of hollow fiber membranes 6 that are aligned vertically (the Z direction), and an upper holding member that fixes the upper ends of the plurality of hollow fiber membranes 6. 7 and a lower holding member 8 that forms a pair with the upper holding member 7 and fixes the lower ends of the plurality of hollow fiber membranes 6.

  In the filtration device 1, the plurality of filtration modules 2 includes an upper holding member 7 and a lower holding member 8 that are formed in a bar shape elongated in the Y direction, and a plurality of hollow fiber membranes 6 are formed on the upper holding member 7 and the lower holding member. 8 are arranged in a curtain shape along the longitudinal direction (Y direction). That is, the upper holding member 7 and the lower holding member 8 hold the plurality of hollow fiber membranes 6 in alignment in the elongated rectangular holding region R as shown in FIG. Since the hollow fiber membranes 6 are arranged in a curtain shape in this way, the bubbles G can relatively easily enter the center of the hollow fiber membrane 6 in the thickness direction (X direction) of the curtain. The turbidity removal effect by the air supply module 4 to be described later can be promoted.

As shown in FIG. 4, the vertical interval between the pair of holding members 7 and 8 in the filtration module 2 is A, the average interval between the holding regions R of the hollow fiber membranes 6 of adjacent filtration modules is B, and a pair of holdings. When the average effective length when the hollow fiber membrane 6 exposed between the members 7 and 8 is wet is C, the lower limit of the value of (C ² -A ² ) ^0.5 / 2B is 10. Is more preferable. On the other hand, the upper limit of the value of (C ² -A ² ) ^0.5 / 2B is 20, and 18 is more preferable. When the value of (C ² -A ² ) ^0.5 / 2B is less than the lower limit, the turbidity removal effect cannot be sufficiently promoted for the bubbles due to insufficient shaking of the hollow fiber membrane 6. There is a fear. On the contrary, when the value of (C ² -A ² ) ^0.5 / 2B exceeds the upper limit, the hollow fiber membranes 6 are likely to be entangled with each other, which may hinder removal of turbidity due to bubbles.

  In the filtration module 2, the average effective length when the hollow fiber membrane 6 exposed between the pair of holding members 7 and 8 is dried is that unnecessary tension is applied to the hollow fiber membrane 6 when the filtration module 2 is not used. In order to prevent the hollow fiber membrane 6 from being damaged by acting, it is preferable that the distance is larger than the average interval A in the vertical direction of the pair of holding members 7 and 8.

  In the filtration module 2, the lower limit of the average distance A in the vertical direction (Z direction) between the holding members 7 and 8 is preferably 2.0 m, and more preferably 2.5 m. On the other hand, the upper limit of the vertical distance A between the holding members 7 and 8 is preferably 4.0 m, and more preferably 3.5 m. When the average vertical distance A between the holding members 7 and 8 is less than the above lower limit, the entanglement between the hollow fiber membranes hardly occurs even in the conventional filtration device, so that there is a sufficient advantage in applying the present invention. There is a risk that it will not be recognized. On the contrary, when the average distance A in the vertical direction between the holding members 7 and 8 exceeds the upper limit, the effective length of the hollow fiber membrane 6 is increased, so that the hollow fiber membrane 6 is easily stretched by its own weight, etc. There is a possibility that the entanglement between the hollow fiber membranes 6 cannot be sufficiently suppressed even by the invention.

  The lower limit of the average interval B between the holding regions R of the filtration modules 2 adjacent in the X direction is preferably 15 mm and more preferably 20 mm. On the other hand, the upper limit of the average interval B between the holding regions R is preferably 50 mm, and more preferably 40 mm. When the average interval B between the holding regions R is less than the lower limit, it may be difficult to prevent the entanglement of the hollow fiber membrane 6 between the filtration modules 2 and sufficiently promote the turbidity removing effect on the bubbles. There is a risk that it cannot be done. On the contrary, when the average interval B between the holding regions R exceeds the upper limit, the membrane area per volume of the filtration device 1 may be reduced, and the processing capability of the filtration device 1 may be insufficient.

<Hollow fiber membrane>
The hollow fiber membrane 6 is formed by forming a porous membrane in a tubular shape that allows water to pass therethrough and prevents permeation of particles contained in the water to be treated.

  The main component of the hollow fiber membrane 6 is PTFE. Thus, when the main component is PTFE, the hollow fiber membrane 6 is excellent in chemical resistance, heat resistance, weather resistance, incombustibility, and the like. In addition to the PTFE, the hollow fiber membrane 6 may be appropriately blended with additives such as other polymers and lubricants.

  The hollow fiber membrane 6 is preferably made of PTFE made porous by stretching. The PTFE stretching may be uniaxial stretching or biaxial stretching.

  As a minimum of the tensile strength of hollow fiber membrane 6, 50 MPa is preferred and 60 MPa is more preferred. When the tensile strength of the hollow fiber membrane 6 is less than the above lower limit, durability against surface cleaning with bubbles may be reduced. On the other hand, the upper limit of the tensile breaking load of the hollow fiber membrane 6 is generally 150N. The tensile breaking load means the maximum tensile stress when a tensile test is performed at a distance between marked lines of 100 mm and a test speed of 100 mm / min in accordance with JIS-K7161 (1994).

  As a minimum of the average outside diameter of hollow fiber membrane 6, 1.5 mm is preferred and 2.0 mm is more preferred. On the other hand, the upper limit of the average outer diameter of the hollow fiber membrane 6 is preferably 4.0 mm, more preferably 3.0 mm. When the average outer diameter of the hollow fiber membrane 6 is less than the above lower limit, the mechanical strength of the hollow fiber membrane 6 may be insufficient, or the cross-sectional area of the lumen may be insufficient and the filtration capability may be insufficient. is there. On the other hand, when the average outer diameter of the hollow fiber membrane 6 exceeds the above upper limit, the total area of the hollow fiber membrane 6 may be insufficient, and the filtration capacity may be insufficient.

  The lower limit of the average inner diameter of the hollow fiber membrane 6 is preferably 0.3 mm, and more preferably 0.5 mm. On the other hand, the upper limit of the average inner diameter of the hollow fiber membrane 6 is preferably 3.0 mm, more preferably 2.0 mm. When the average inner diameter of the hollow fiber membrane 6 is less than the above lower limit, the pressure loss when the filtered liquid in the hollow fiber membrane 6 is discharged may increase. Conversely, when the average inner diameter of the hollow fiber membrane 6 exceeds the above upper limit, the mechanical strength of the hollow fiber membrane 6 and the ability to prevent the passage of solid matter may be insufficient.

  The lower limit of the porosity of the hollow fiber membrane 6 is preferably 70%, and more preferably 75%. On the other hand, the upper limit of the porosity of the hollow fiber membrane 6 is preferably 90%, more preferably 85%. If the porosity of the hollow fiber membrane 6 is less than the lower limit, water permeability may be insufficient. Conversely, when the porosity of the hollow fiber membrane 6 exceeds the above upper limit, the mechanical strength and scratch resistance of the hollow fiber membrane 6 may be insufficient. The porosity means the ratio of the total pore volume to the volume of the hollow fiber membrane 6 and can be determined by measuring the density of the hollow fiber membrane 6 in accordance with ASTM-D-792.

  The hollow fiber membrane 6 can be configured to have a porous tube-like base material layer and a porous filtration layer laminated on the outer peripheral surface of the base material layer. Thus, by making hollow fiber membrane 6 into a multilayer structure, water permeability and mechanical strength can be made compatible, and also the turbidity removal effect by air bubbles can be made more effective.

(Base material layer)
The main component of the base material layer is PTFE. Thus, when the main component is PTFE, the hollow fiber membrane 6 is excellent in chemical resistance, heat resistance, weather resistance, incombustibility, and the like. In addition to the PTFE, the base material layer may contain other polymers, additives such as a lubricant, and the like as appropriate.

  The base material layer is preferably made of PTFE made porous by stretching. The PTFE stretching may be uniaxial stretching or biaxial stretching.

  As a minimum of the number average molecular weight of PTFE of a base material layer, 500,000 are preferable and 2 million are more preferable. On the other hand, the upper limit of the number average molecular weight of PTFE of the base material layer is preferably 20 million. When the number average molecular weight of PTFE of the base material layer is less than the lower limit, the surface of the hollow fiber membrane 6 may be easily damaged, and the mechanical strength of the hollow fiber membrane 6 may be reduced. On the other hand, when the number average molecular weight of PTFE of the base material layer exceeds the above upper limit, there is a possibility that it becomes difficult to form the pores of the hollow fiber membrane 6.

  As the base material layer, for example, a tube obtained by extruding PTFE can be used. Thus, by using an extrusion-molded tube as the base material layer, the base material layer can have mechanical strength and can be easily made porous.

(Filtration layer)
The filtration layer can be formed by spirally winding the belt-like body around the base material layer so that both edges thereof overlap.

  The lower limit of the overlapping area ratio between the strips in the filtration layer is preferably 20%, and more preferably 25%. On the other hand, the upper limit of the overlapping area ratio between the strips in the filtration layer is preferably 40%, and more preferably 35%. When the overlapping area ratio between the strips in the filtration layer is less than the lower limit, it is difficult to wind the strips so that no gap is formed between the strips, and the production efficiency of the hollow fiber membrane 6 may be insufficient. Conversely, when the overlapping area ratio between the strips in the filtration layer exceeds the upper limit, the filtration capacity (flux) of the hollow fiber membrane 6 may be unnecessarily lowered.

  The material of the filtration layer can be the same as the material of the base material layer. The filtration layer is preferably made of PTFE made porous by stretching, and more preferably multiaxially stretched to form uniform pores.

  The lower limit of the average thickness of the filtration layer is preferably 1 μm, and more preferably 2 μm. On the other hand, the upper limit of the average thickness of the filtration layer is preferably 100 μm or less, and more preferably 80 μm. When the average thickness of the filtration layer is less than the above lower limit, the ability of the hollow fiber membrane 6 to prevent the passage of solid matter may be insufficient. On the other hand, when the average thickness of the filtration layer exceeds the above upper limit, the liquid flux that permeates through the hollow fiber membrane 6 may be insufficient.

  The lower limit of the average pore diameter of the hollow fiber membrane 6 is preferably 0.01 μm. On the other hand, the upper limit of the average diameter of the pores of the hollow fiber membrane 6 is preferably 0.45 μm, and more preferably 0.1 μm. If the average diameter of the pores of the hollow fiber membrane 6 is less than the above lower limit, the water permeability may be lowered. On the contrary, when the average diameter of the pores of the hollow fiber membrane 6 exceeds the above upper limit, there is a possibility that the permeation of impurities contained in the water to be treated into the hollow fiber membrane 6 cannot be prevented. The average pore diameter means the average pore diameter on the outer peripheral surface (filtration layer surface) of the hollow fiber membrane 6, and is a pore diameter distribution measuring device (for example, “Porous Material Automatic Fine Cell” manufactured by Porous Materials). It can be measured by a pore size distribution measuring system ").

  As described above, the hollow fiber membrane 6 is arranged in a matrix form in the long side direction and the short side direction in the rectangular holding region R of the upper holding member 7 and the lower holding member 8 as described above.

  The lower limit of the ratio (La / Lb) of the average length La in the long side direction to the average length Lb in the short side direction of the holding region R is preferably 10, and more preferably 20. On the other hand, the upper limit of the ratio of the average length La in the long side direction to the average length Lb in the short side direction of the holding region R is preferably 50, and more preferably 40. When the ratio of the average length La in the long side direction to the average length Lb in the short side direction is less than the lower limit, the length in the short side direction becomes too large, and bubbles are formed to the center of the bundle of hollow fiber membranes 6. There is a possibility that it cannot be supplied or the area of the holding region R becomes small and a sufficient filtration area cannot be obtained. Conversely, if the ratio of the average length La in the long side direction of the holding region R to the average length Lb in the short side direction exceeds the upper limit, the filtration module 2 becomes excessively long in the long side direction, and the filtration module 2 May not be easy to handle.

  The lower limit of the ratio of the average pitch (center distance) in the long side direction to the average pitch in the short side direction of the hollow fiber membrane 6 is preferably 1.2, and more preferably 1.5. On the other hand, the upper limit of the ratio of the average pitch in the long side direction to the average pitch in the short side direction of the hollow fiber membrane 6 is preferably 2.5, and more preferably 2. In the case where the ratio of the average pitch in the long side direction of the hollow fiber membrane 6 to the average pitch in the short side direction is less than the lower limit, there are sufficient bubbles in the gap between the hollow fiber membranes 6 in the short side direction of the holding region R. May not be introduced. On the other hand, when the ratio of the average pitch in the long side direction of the hollow fiber membrane 6 to the average pitch in the short side direction exceeds the upper limit, the density of the hollow fiber membrane 6 in the long side direction becomes small and the filtration capacity is reduced. May be insufficient.

  The lower limit of the cross-sectional occupancy ratio of the hollow fiber membrane 6 in the holding region R (occupation ratio including the area of the lumen of the hollow fiber membrane 6) is preferably 30%, and more preferably 32%. On the other hand, the upper limit of the cross-sectional occupation ratio of the hollow fiber membrane 6 in the holding region R is preferably 40%, more preferably 38%. When the cross-sectional occupation ratio of the hollow fiber membrane 6 is less than the lower limit, the number of the hollow fiber membranes 6 per unit area is reduced, and there is a possibility that sufficient filtration efficiency cannot be obtained. On the contrary, when the cross-sectional occupancy of the hollow fiber membrane 6 exceeds the above upper limit, the gap between the hollow fiber membranes 6 becomes excessively small, and air bubbles are supplied to the hollow fiber membrane 6 inside the holding region R to form the hollow fiber membrane. There is a possibility that adhesion of turbidity to 6 cannot be suppressed.

  As a minimum of the number (arrangement number) of the hollow fiber membranes 6 arranged in the short side direction in the holding region R, 8 is preferable, and 12 is more preferable. On the other hand, the upper limit of the number of hollow fiber membranes 6 arranged in the short side direction is preferably 50, more preferably 40. When the number of the hollow fiber membranes 6 arranged in the short side direction is less than the lower limit, there is a possibility that a sufficient filtration area per arrangement area cannot be secured. On the other hand, when the number of hollow fiber membranes 6 arranged in the short side direction exceeds the above upper limit, it becomes difficult to supply air bubbles to the central part in the short side direction of the bundle of hollow fiber membranes 6, and a sufficient cleaning effect is obtained. May not be obtained.

  The lower limit of the ratio of the average pitch in the short side direction to the average outer diameter of the hollow fiber membrane 6 is preferably 1. On the other hand, the upper limit of the ratio of the average pitch in the short side direction to the average outer diameter of the hollow fiber membrane 6 is preferably 1.5, and more preferably 1.4. When the ratio of the average pitch in the short side direction with respect to the average outer diameter of the hollow fiber membrane 6 is less than the lower limit, the hollow fiber membrane 6 is disposed in a state of being crushed in the radial direction, and thus it is difficult to manufacture. There is a risk of becoming. On the contrary, when the ratio of the average pitch in the short side direction to the average outer diameter of the hollow fiber membrane 6 exceeds the upper limit, the density of the hollow fiber membrane 6 in the long side direction becomes small, and the filtration capacity is insufficient. There is a risk.

  The plurality of hollow fiber membranes 6 may be divided into a plurality of bundles along the longitudinal direction (Y direction) of the upper holding member 7 and the lower holding member 8. That is, the upper side holding member 7 and the lower side holding member 8 may have a plurality of regions with a plurality of hollow fiber membranes 6 arranged in the longitudinal direction at intervals. Thus, by dividing the hollow fiber membrane 6 into a plurality of bundles and providing a gap between the bundles, the bundle of hollow fiber membranes 6 can vibrate in the longitudinal direction of the upper holding member 7 and the lower holding member 8. Therefore, the turbidity adhering to the surface of the hollow fiber membrane 6 by this vibration can be efficiently shaken off. Further, since there is a gap between the bundles of the hollow fiber membranes 6, the bubbles G can relatively easily enter the bundle of the hollow fiber membranes 6 in the longitudinal direction of the upper holding member 7 and the lower holding member 8. Therefore, the turbidity removal effect by the air bubbles supplied from the air supply module 4 described later can be further promoted.

<Upper holding member>
The upper holding member 7 is a member that holds the upper ends of the plurality of hollow fiber membranes 6, communicates with the lumens of the plurality of hollow fiber membranes 6, and has an internal channel that collects filtered water. A pipe of the discharge mechanism 5 is connected to the internal flow path, and the filtered water that has permeated into the hollow fiber membranes 6 is discharged.

  The upper holding member 7 is elongated in the horizontal direction (the direction perpendicular to the direction in which the hollow fiber membranes 6 are aligned) and has a substantially constant width. The cross-sectional shape of the upper holding member 7 is not particularly limited, and may be, for example, a polygonal shape, a circular shape, etc., but a square shape that is easy to mold and fix a plurality of hollow fiber membranes 6 is suitably employed. The Further, the upper holding member 7 may have an engagement structure for facilitating the support by the support 3.

  As a specific example, as shown in FIG. 5, the upper holding member 7 can be configured to have a hollow casing 7 a in which the lower part is opened and the upper ends of a plurality of hollow fiber membranes 6 are inserted from the lower part. .

  In this example, the upper holding member 7 is filled with a resin composition 7b so as to leave an internal space forming the discharge portion between the inner surface of the side wall of the hollow casing 7a and the outer peripheral surface of the hollow fiber membrane 6. . More specifically, a bundle in which the upper end portions of the plurality of hollow fiber membranes 6 are bonded in advance with the resin composition 7b is inserted into the hollow casing 7a, and between the resin composition 7b and between the resin composition 7b and the inner wall of the hollow casing 7a, The hollow fiber membrane 6 is being fixed with respect to the hollow casing 7a by the further filling of the resin composition 7b in between.

  The hollow casing 7a is provided with a discharge nozzle 7c that communicates with the internal space and is connected to a discharge mechanism.

  Examples of the material of the hollow casing 7a include a resin composition mainly composed of PTFE, vinyl chloride, polyethylene, ABS resin and the like.

  Any resin composition 7b may be used as long as it has high adhesion to the hollow fiber membrane 6 and the hollow casing 7a and can be cured in the hollow casing 7a. On the other hand, an epoxy resin and a urethane resin that have high adhesiveness and can reliably prevent the hollow fiber membrane 6 from falling off are preferable. By filling the hollow casing 7a with the resin composition 7b, the space between the hollow fiber membrane 6 and the side wall of the hollow casing 7a can be hermetically sealed. As a result, the discharge part in the upper holding member 7 and the outside of the hollow fiber membrane 6 can be reliably separated, and the untreated water that has not been filtered can be prevented from being mixed into the filtered filtered water.

<Lower holding member>
The lower holding member 8 is a member that holds the lower ends of the plurality of hollow fiber membranes 6. The lower holding member 8 may have the same configuration as the upper holding member 7 or may have a configuration that does not have a discharge portion that seals the lower end portion of the hollow fiber membrane 6. The structure, average width, average length, material, and the like of the lower holding member 8 can be the same as those of the upper holding member 7.

  Further, the lower holding member 8 may be configured such that one hollow fiber membrane 6 is bent in a U shape and folded back. In this case, the upper holding member 7 holds both ends of the hollow fiber membrane 6.

[Support]
As described above, the support 3 holds the upper holding member 7 and the lower holding member 8 of the plurality of filtration modules 2, so that the plurality of filtration modules 2 are stored in the liquid to be treated stored in the filtration tank W. Dispose in an immersed state.

  The support 3 is preferably configured to be removed from the filtration tank W while holding the filtration module 2. Moreover, it is preferable that the support body 3 is comprised so that the air supply module 4 mentioned later may be hold | maintained under the filtration module 2. FIG.

[Air supply module]
The air supply module 4 is disposed between the filtration modules 2 in a plan view, and has a plurality of air supply pipes 9 that supply gas that forms bubbles G. The plurality of air supply pipes 9 have a plurality of bubble discharge ports 9 a for discharging bubbles G. The diameter of the bubble discharge port 9a of the air supply pipe 9 can be set to 1 mm or more and 10 mm or less, for example. The air supply module 4 supplies air bubbles G to the hollow fiber membrane 6 from the gap between the lower holding members 8 and shakes the hollow fiber membrane 6 to remove turbidity adhering to the hollow fiber membrane 6.

  The gas forming the bubbles G supplied from the air supply module 4 is not particularly limited as long as it is inert, but air is preferably used from the viewpoint of running cost.

[Discharge mechanism]
The discharge mechanism 5 is connected to the discharge nozzles 7 c of the plurality of filtration modules 2, collects the treated liquid obtained by filtering the liquid to be treated by the hollow fiber membrane 6, and collects the treated liquid from the collected water pipe 10. And a suction pump 11 for suction.

[advantage]
The filtration device 1, the value of ^{(C 2 -A 2) 0.5 /} 2B by the within the above range, the rocking of hollow fiber membrane 6 of the filtration module 2 by bubbles supplied from the air supply module 4 And the hollow fiber membranes 6 are not easily entangled with each other. For this reason, the said filtration apparatus 1 can remove efficiently the turbidity adhering to the hollow fiber membrane 6 with the bubble.

[Other Embodiments]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not limited to the configuration of the embodiment described above, but is defined by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims. The

  In the filtration device, the configuration of the air supply module is not limited. For example, a device that discharges gas from a perforated plate, a device that injects gas from a diffuser or a sparger, a device that intermittently injects air bubbles, or a device that injects air bubbles You may use the bubbling jet nozzle etc. which mix and inject.

  The filtration device may not have a discharge mechanism. As an example, the filtration device is configured such that the filtered liquid is sucked by an external suction device or the inside of the water tank can be pressurized, and the liquid passes through the hollow fiber membrane and flows out of the device by external pressure. It may be a thing.

  EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example.

<Prototype example 1>
PTFE hollow fiber membranes with an outer diameter of 2.3 mm, an inner diameter of 1.1 mm, a film thickness of 0.6 mm, and a porosity of 80% are prepared, and the average effective when both ends of a plurality of hollow fiber membranes are wetted by a pair of holding members A plurality of trial examples 1 of the filtration module were manufactured by fixing the length (C) to 3100 mm and connecting the pair of holding members with the support member so that the distance (A) thereof was 3060 mm.

<Prototype example 2>
Except for the point that the average effective length (C) of a plurality of hollow fiber membranes when wet was 3140 mm, a plurality of prototype examples 2 of the filtration module were manufactured in the same manner as the prototype example 1.

<Prototype example 3>
Except for the point that the average effective length (C) of a plurality of hollow fiber membranes when wet was set to 3200 mm, a plurality of prototype examples 3 of the filtration module were manufactured in the same manner as in the prototype example 1.

<Prototype example 4>
Except for the point that the average effective length (C) when wet of a plurality of hollow fiber membranes was set to 3230 mm, a plurality of prototype examples 4 of the filtration module were manufactured in the same manner as the prototype example 1.

<Prototype example 5>
Except for the point that the average effective length (C) of a plurality of hollow fiber membranes when wet was set to 3260 mm, a plurality of trial manufacture examples 5 of the filtration module were manufactured in the same manner as the test example 1.

<Prototype Example 6>
A prototype of a filtration module similar to Prototype Example 1 except that the average effective length (C) when wet of a plurality of hollow fiber membranes is 2140 mm and the distance (A) between the pair of holding members is 2040 mm A number of prototypes 6 were made.

<Prototype Example 7>
A plurality of trial manufacture examples 7 of the filtration module were manufactured in the same manner as the test example 6 except that the average effective length (C) when the plurality of hollow fiber membranes were wet was 2220 mm.

<Prototype Example 8>
Except for the point that the average effective length (C) when wet of a plurality of hollow fiber membranes was 2300 mm, a plurality of trial manufacture examples 8 of the filtration module were manufactured in the same manner as the test example 6.

<Test>
Prototype examples 1 to 7 of the filtration module are each held by a support so that the interval (B) between the holding regions of the hollow fiber membranes is 25 mm, incorporated in a filtration device, immersed in a water tank for storing water, and below After performing a test operation for continuously filtering water for 4 weeks while supplying air bubbles, it was confirmed whether or not the entanglement between the hollow fiber membranes occurred. As a result, entanglement between the hollow fiber membranes occurred in the prototype examples 4, 5, and 8.

  Further, the filtration module after the trial operation was dried in the atmosphere for 4 weeks, and the state of the hollow fiber membrane was confirmed. As a result, the tear of the hollow fiber membrane was confirmed only in Prototype Example 1.

In the following Table 1, the trial production conditions of trial production examples 1 to 7 of the filtration module and the value of (C ² -A ² ) ^0.5 / 2B are shown.

As a result, by optimizing the value of (C ² -A ² ) ^0.5 / 2B, the entanglement of the hollow fiber membrane is prevented and the removal of turbidity due to bubbles is promoted, while the hollow fiber membrane at the time of drying It was confirmed that the damage can be prevented.

  As described above, the filtration module of the present invention can improve the efficiency of removing turbidity of the hollow fiber membrane, and can be suitably used in various fields as a solid-liquid separation treatment apparatus.

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration module 3 Support body 4 Air supply module 5 Discharge mechanism 6 Hollow fiber membrane 7 Upper holding member 7a Hollow casing 7b Resin composition 7c Discharge nozzle 8 Lower holding member 9 Air supply pipe 9a Bubble discharge port 10 Water collection pipe 11 Suction pump A Vertical distance B between holding members Distance C between holding regions Effective length G when the hollow fiber membrane is wet G Bubble La Length in the long side of the holding region Lb Length in the short side direction of the holding region R Holding area W Filtration tank

Claims (5)

A plurality of filtration modules having a plurality of hollow fiber membranes aligned vertically and a pair of holding members for fixing the upper and lower ends of the plurality of hollow fiber membranes;
A support for holding the plurality of filtration modules in parallel and at equal intervals;
A filtration device comprising one or more air supply modules for supplying air bubbles from below the filtration module,
The main component of the hollow fiber membrane is polytetrafluoroethylene,
An average interval in the vertical direction of the pair of holding members in the filtration module is A, an average interval between the holding regions of the hollow fiber membranes in the adjacent filtration modules is B, and the hollow fiber membrane exposed between the pair of holding members C is the average effective length when wet
^{(C 2 -A 2) 0.5 /} 2B filtering device value is 10 or more 20 or less.   The filtration device according to claim 1, wherein an average effective length when the hollow fiber membrane exposed between the pair of holding members is dried is larger than an average interval A in the vertical direction of the pair of holding members.   The filtration device according to claim 1 or 2, wherein an average interval A in the vertical direction of the pair of holding members is 2.0 m or more and 4.0 m or less.   The filtration device according to claim 1, 2 or 3, wherein an average interval B between the holding regions is 15 mm or more and 50 mm or less.   The filtration device according to any one of claims 1 to 4, wherein an average outer diameter of the hollow fiber membrane is 1.5 mm or more and 4.0 mm or less.

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