WO2018012178A1

WO2018012178A1 - Aeration unit and filtration device

Info

Publication number: WO2018012178A1
Application number: PCT/JP2017/021721
Authority: WO
Inventors: 岳松本; 森田　徹; 池田　啓一
Original assignee: 住友電気工業株式会社
Priority date: 2016-07-15
Filing date: 2017-06-13
Publication date: 2018-01-18
Also published as: TW201803640A; JP2018008249A

Abstract

The aeration unit of an embodiment of the present invention for supplying a cleaning gas for an immersed filtration device is provided with: a straight tubular aeration header, which has a gas introduction port through which the cleaning gas is introduced and the center axis of which is disposed in the horizontal direction; and multiple straight tubular aeration pipes, which are in communication with the aeration header, extend from the side walls of the aeration header, and have multiple aeration holes. The lowest position of the inner surface of the multiple aeration pipes is near the lowest position of the inner surface of the aeration header in the vertical direction.

Description

Aeration unit and filtration device

The present invention relates to an air diffusion unit and a filtration device.
This application claims priority based on Japanese Patent Application No. 2016-140580 filed on July 15, 2016, and incorporates all the description content described in the above Japanese application.

In the filtration device described in Japanese Patent Application Laid-Open No. 2011-115794, a configuration is adopted in which bubbles are introduced between a plurality of hollow fiber membranes constituting the filtration module and impurities adhering to the surface of the hollow fiber membranes are removed by the bubbles. ing.

JP 2011-115794 A

An aeration unit according to an aspect of the present invention is an aeration unit that supplies a cleaning gas of an immersion type filtration device, and has a gas introduction port into which the cleaning gas is introduced, with a central axis in a horizontal direction. A straight tubular diffuser header disposed; and a plurality of straight tubular diffuser pipes communicating with the diffuser header, extending from a side wall of the diffuser header, and having a plurality of diffuser holes, The lowest position of the inner surfaces of the plurality of diffuser tubes is close to the lowest position of the inner surface of the diffuser header in the vertical direction.

A filtration device according to an aspect of the present invention is an immersion type filtration device including a plurality of filtration modules having a plurality of hollow fiber membranes and a gas supply module that supplies bubbles from below the plurality of filtration modules. The gas supply module includes the aeration unit.

It is a typical front view showing the aeration unit concerning a first embodiment of the present invention. FIG. 2 is a schematic plan view of the air diffusion unit of FIG. 1. FIG. 3 is an enlarged cross-sectional view taken along line AA of the air diffusion unit of FIG. 2. It is a typical front view which shows a filtration apparatus provided with the aeration unit of FIG. It is a typical side view of the filtration apparatus of FIG. It is a typical side view which shows the filtration apparatus which concerns on embodiment different from the filtration apparatus of FIG. It is a typical partial front view which shows the gas supply module of the filtration apparatus of FIG. It is a typical perspective view which shows the intermittent bubble generation unit of the gas supply module of FIG. FIG. 9 is a schematic plan view of the intermittent bubble generation module of FIG. 8. FIG. 10 is a cross-sectional view of the intermittent bubble generation module of FIG. 9 taken along line BB. FIG. 10 is a sectional view taken along line CC of the intermittent bubble generation module of FIG. 9.

[Problems to be solved by the present disclosure]
As a solid-liquid separation processing apparatus in a manufacturing process such as sewage treatment or medicine, a filtration apparatus having a filtration module in which a plurality of hollow fiber membranes are collected is used. Such a filtration device is used by being immersed in a liquid to be treated. The hollow fiber membrane surface prevents permeation of impurities contained in the liquid to be treated, and the filtration treatment is performed by allowing other than the impurities to permeate inside. Do.

However, such a filtering device prevents the permeation of impurities contained in the liquid to be treated by the surface of the hollow fiber membrane, so that impurities that have not permeated inside adhere to the surface of the hollow fiber membrane. Therefore, in this filtration device, there is a possibility that the filtration efficiency of the liquid that should be originally filtered is reduced by the impurities attached to the surface of the hollow fiber membrane.

In view of such a problem, a filtering device described in Patent Document 1 has been proposed. The filtration device described in Patent Literature 1 includes an air diffuser that discharges air bubbles between a plurality of hollow fiber membranes constituting a filtration module. In this filtration device, the air diffuser has one or a plurality of air holes, the bubbles released from the air holes rub against the surface of the hollow fiber membrane, and the impurities are removed by swinging the hollow fiber membrane. can do.

In the filtering device described in Patent Document 1, a plurality of air diffuser tubes are connected to a straight tubular header, and bubbles can be released from the air diffuser holes of the plurality of air diffuser tubes by introducing gas into the header. it can. However, when multiple diffuser pipes are connected to one header, the amount of bubbles released from the diffuser holes of the diffuser pipe connected to the vicinity of the gas inlet part of the header is away from the gas inlet part of the header. It tends to be larger than the amount of bubbles released from the air diffuser holes of the air diffuser connected to the. Therefore, this filtration apparatus has the subject that it is difficult to equalize the discharge amount of the bubbles from the plurality of diffusion holes of the plurality of diffusion tubes.

In view of the circumstances as described above, it is possible to equalize the discharge amount of bubbles from a plurality of air diffuser holes of a plurality of air diffuser tubes, thereby achieving a uniform cleaning effect of the plurality of filtration modules. An object is to provide an air diffusion unit and a filtration device.

[Effects of the present disclosure]
According to the present disclosure, it is possible to equalize the amount of bubbles released from the plurality of air diffusion holes of the plurality of air diffusion tubes, and thereby to achieve uniform cleaning effects of the plurality of filtration modules.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.

(1) An aeration unit according to an aspect of the present invention is an aeration unit that supplies a cleaning gas of an immersion type filtration device, and has a gas introduction port into which the cleaning gas is introduced, and a central axis is A straight tubular diffuser header disposed in a horizontal direction, and a plurality of straight tubular diffuser tubes communicating with the diffuser header, extending from a side wall of the diffuser header, and having a plurality of diffuser holes. And the lowest position of the inner surfaces of the plurality of diffuser tubes is close to the lowest position of the inner surface of the diffuser header in the vertical direction.

The diffuser unit is configured to be able to release the gas introduced from the gas inlet port of the diffuser header through the diffuser holes of the diffuser tubes. Since the lowest position of the inner surface of the plurality of diffuser tubes is close to the lowermost position of the inner surface of the diffuser header in the vertical direction, the diffuser unit is configured to transfer the gas introduced into the diffuser header to the plurality of diffuser tubes. Easy to supply uniformly. Therefore, the air diffuser unit can achieve a uniform discharge amount of air bubbles from a plurality of air diffuser holes of a plurality of air diffuser tubes, thereby achieving a uniform cleaning effect of the plurality of filtration modules. .

(2) The vertical distance between the uppermost position of the inner surfaces of the plurality of diffuser tubes and the uppermost position of the inner surfaces of the diffuser headers is such that the lowest position of the inner surfaces of the diffuser tubes and the innermost surfaces of the diffuser headers. It may be larger than the vertical distance from the lower position. The vertical distance between the uppermost position of the inner surfaces of the plurality of diffuser tubes and the uppermost position of the inner surfaces of the diffuser headers is the vertical distance between the lowest position of the inner surfaces of the diffuser tubes and the lowest position of the inner surfaces of the diffuser headers. By being larger than the directional distance, it is easy to form a gas layer above the diffuser header by the gas introduced into the diffuser header. Therefore, by gradually lowering the interface between the gas layer and the liquid to be treated, it is easy to supply gas uniformly to the plurality of diffuser tubes, so that bubbles are released from the plural diffuser holes of the multiple diffuser tubes. A uniform amount can be promoted. In addition, by gradually lowering the interface between the gas layer and the liquid to be processed, the liquid to be processed in the diffuser header can be easily and reliably drained through the plurality of air diffusers.

(3) The gas introduction port may be provided above the uppermost position of the inner surfaces of the plurality of diffuser tubes. By providing the gas inlets above the uppermost position of the inner surfaces of the plurality of diffuser tubes, it is possible to easily form a gas layer above the diffuser header by the gas introduced into the diffuser header. it can. Therefore, by gradually lowering the interface between the gas layer and the liquid to be treated, gas can be evenly supplied to the plurality of diffuser tubes, and bubbles from the plurality of diffuser holes of the plurality of diffuser tubes can be supplied. Uniformity of the release amount can be promoted. In addition, by gradually lowering the interface between the gas layer and the liquid to be processed, the liquid to be processed in the diffuser header can be easily and reliably drained through the plurality of air diffusers.

(4) A filtration device according to another aspect of the present invention includes a plurality of filtration modules having a plurality of hollow fiber membranes, and an immersion type including a gas supply module that supplies bubbles from below the plurality of filtration modules. The gas supply module includes the air diffusion unit.

Since the filtration device includes the aeration unit, as described above, it is possible to equalize the amount of bubbles released from the plurality of aeration holes of the plurality of aeration tubes, thereby cleaning the plurality of filtration modules. The effect can be homogenized.

(5) The gas supply module may further include a plurality of intermittent bubble generation units disposed vertically above the plurality of air diffusion holes. Since the gas supply module further includes a plurality of intermittent bubble generating units disposed vertically above the plurality of air diffusion holes, relatively large bubbles can be discharged, thereby increasing the energy of each bubble. The cleaning effect on the surface of the plurality of hollow fiber membranes can be further enhanced. In addition, if there are diffused holes with a small amount of released pores, the diameter of bubbles discharged from the intermittent bubble generating unit disposed vertically above the diffused holes is reduced and the discharge interval is extended, thereby improving the cleaning effect. However, when the amount of bubbles released from the plurality of air diffusion holes is uniform, the cleaning effect can be easily and reliably improved by each intermittent bubble generation module.

In the present invention, the “horizontal direction” is not limited to a strict horizontal direction, and includes a direction inclined at an angle of 5 ° or less, preferably 3 ° or less with respect to the horizontal direction. Further, the “side walls of the diffuser header” refers to a pair of walls that face in the horizontal direction in a cross section perpendicular to the central axis of the diffuser header.

[Details of the embodiment of the present invention]
Hereinafter, an air diffusion unit and a filtration device according to the present invention will be described in detail with reference to the drawings.

[First embodiment]
<Aeration unit>
The aeration unit 1 in FIGS. 1 and 2 supplies a cleaning gas for an immersion type filtration apparatus. Examples of the filtration device include a microfiltration device and an ultrafiltration device including a filtration module having a plurality of hollow fiber membranes and a gas supply module that supplies bubbles from below the filtration module. The air diffusion unit 1 is used for this gas supply module. The air diffusion unit 1 is used in a state immersed in the liquid to be treated.

The air diffusion unit 1 has a gas introduction port 11 into which cleaning gas is introduced, a straight tubular air diffusion header 2 whose central axis is disposed in the horizontal direction, and the air diffusion header 2. And a plurality of straight tubular air diffusion tubes 3 having a plurality of air diffusion holes 12 extending from the two side walls. As shown in FIG. 3, in the air diffusion unit 1, the lowest position h _{1 on} the inner surface of the plurality of air diffusion tubes 3 is close to the lowest position h _{2 on} the inner surface of the air diffusion header 2 in the vertical direction. Specifically, the diffuser unit 1 has a plurality of diffuser tubes 3 arranged in the horizontal direction, and the lowest position h _{1 on the} inner surface of the diffuser tube 3 connected to the diffuser header 2. There are close at the lowest position h ₂ to the vertical direction of the inner surface of the air diffuser header 2.

In the diffuser unit 1, when gas is introduced into the diffuser header 2 from the gas inlet 11 of the diffuser header 2, a gas layer and a liquid layer (processed liquid layer) are formed in the diffuser header 2. . That is, since the diffuser header 2 is used in a state of being immersed in the liquid to be processed, the liquid to be processed is filled inside before introducing the gas. When the gas is introduced from the gas inlet 11 in this state, the specific gravity of the gas is smaller than the specific gravity of the liquid to be processed, so that the gas fills the space between the upper inner surface of the diffuser header 2 and the liquid to be processed. . In the air diffusion unit 1, similarly to the air diffusion header 2, the liquid to be processed is filled in the plurality of air diffusion pipes 3 before the gas is introduced. The diffuser unit 1 is configured such that the gas is introduced into the diffuser header 2, and the interface between the gas layer and the liquid layer is lowered below the uppermost position h ₃ on the inner surface of the diffuser tubes ₃ . A gas flows between the upper inner surface of the air diffusion tube 3 and the liquid to be processed. In the air diffusion unit 1, since the plurality of air diffusion tubes 3 have the plurality of air diffusion holes 12, the gas flowing through the plurality of air diffusion tubes 3 is released as bubbles from the plurality of air diffusion holes 12, thereby A plurality of hollow fiber membranes can be washed. In order to supply gas from the gas layer to all the diffuser tubes 3 simultaneously, it is preferable that the uppermost position h3 on the inner surface of all the diffuser tubes ₃ is equal.

The diffuser unit 1 has a plurality of gases introduced into the diffuser header 2 because the lowest position h _{1 on} the inner surface of the plurality of diffuser tubes 3 is close to the lowest position h _{2 on} the inner surface of the diffuser header 2. It is easy to supply the air diffuser 3 evenly. For this reason, the air diffusion unit 1 can achieve a uniform discharge amount of bubbles from the plurality of air diffusion holes 12 of the plurality of air diffusion tubes 3, thereby achieving a uniform cleaning effect of the plurality of filtration modules. Can do.

The reason why the air diffuser unit 1 can uniformly discharge the air bubbles from the air diffuser holes 12 of the air diffuser tubes 3 will be described below.
Since the air diffusion unit is used by being immersed in the liquid to be processed, the liquid to be processed easily enters the air diffusion unit when immersed in the liquid to be processed. In this regard, in the conventional air diffusion unit, the lowermost position of the inner surface of the plurality of air diffusion pipes is disposed relatively higher than the lowermost position of the inner surface of the air diffusion header. The non-treatment liquid easily collects at a position lower than the lowest position on the inner surface of the air diffusion tube. For this reason, the conventional air diffuser unit is configured such that when the gas is introduced into the air diffuser header, the liquid level of the liquid to be processed accumulated in the air diffuser header is corrugated, and the course of the gas is hindered due to the corrugation. Gas cannot be uniformly supplied to a plurality of diffuser tubes.
On the other hand, in the air diffusion unit 1, the lowest position h _{1 on} the inner surface of the plurality of air diffusion pipes 3 is close to the lowest position h _{2 on} the inner surface of the air diffusion header 2 in the vertical direction. In the header 2, the non-treatment liquid hardly accumulates at a position lower than the lowest position h ₁ on the inner surface of the plurality of diffusion tubes 3, and the gas is caused by the undulation of the liquid surface of the liquid to be treated in the diffusion header 2. Since the path is difficult to be obstructed, the bubbles can be uniformly discharged from the plurality of air diffusion holes 12 of the plurality of air diffusion tubes 3. In order to more accurately suppress the non-treatment liquid from accumulating at a position lower than the lowest position h ₁ on the inner surface of the plurality of air diffusion tubes 3 in the air diffusion header 2 in the air diffusion unit 1, it is preferable that the lowest position h ₁ of the diffuser of the inner surface of the trachea 3 is a neighbor lowest position h ₂ of the inner surface of the air diffuser header 2.

(Aeration header)
The diffuser header 2 has a straight tubular shape as described above, and specifically has a shape having a hollow internal space by sealing both ends in the central axis direction with end walls. The cross-sectional shape of the inner surface perpendicular to the central axis of the diffuser header 2 is not particularly limited, and examples thereof include a rectangular shape, an elliptical shape, a perfect circular shape, an inverted T shape, and an L shape. Of these, the cross-sectional shape is preferably an inverted T-shape. This is because if the cross-sectional shape is an inverted T-shape, it is easy to form a gas layer above the diffuser header 2 while reducing the size of the filter device including the diffuser header 2 and thus the diffuser unit 1.

The inner surface of the diffuser header 2 may be elliptical as described above, but it is preferable to have a horizontal lower surface from the viewpoint of suppressing the liquid to be treated from accumulating inside. Further, as shown in FIGS. 1 and 2, the diffuser header 2 has a plurality of diffuser tubes 3 extending from a pair of opposing side walls, so that the amount of air bubbles released from the diffuser tubes 3 is increased. In order to achieve uniformity, it is preferable that the cross-sectional shape perpendicular to the central axis is symmetrical.

Aeration header 2, above the the uppermost position h ₃ of the inner surface of the plurality of diffuser tubes 3 preferably has a gas layer formation region for forming a gas layer by a gas introduced from the gas inlet 11 . Moreover, it is preferable that this gas layer formation area is provided ranging over the whole area | region of the central-axis direction in which the several diffuser tube 3 is arrange | positioned. This gas layer forming region can be formed, for example, by making the uppermost position h ₄ on the inner surface of the diffuser header 2 higher than the uppermost position h ₃ on the inner surfaces of the plurality of diffuser tubes ₃ by a certain level or more.

The gas inlet 11 is formed on one end side in the central axis direction of the diffuser header 2. For example, as shown in FIG. 2, the gas inlet 11 may be formed on the upper wall of the diffuser header 2 or the end wall on the one end side in the central axis direction of the diffuser header 2. The gas introduction port 11 is configured to be able to introduce gas supplied from the gas pressure feeding unit 2 into the diffuser header 2 by being connected to a gas pressure feeding unit (not shown).

It is preferable that the gas inlet 11 is provided above the uppermost position h ₃ on the inner surface of the plurality of diffuser tubes 3. Aeration unit 1, by gas inlet 11 is provided from the highest position h ₃ of the inner surface of the plurality of diffuser tubes 3 upward, air diffuser header 2 by the gas introduced into the air diffuser header 2 A gas layer can be easily formed above the substrate. Therefore, by gradually lowering the interface between the gas layer and the liquid to be treated, the gas can be uniformly supplied to the plurality of diffusion tubes 3, and the plurality of diffusion holes 12 of the plurality of diffusion tubes 3 can be supplied. It is possible to promote the uniform discharge of bubbles. Further, by gradually lowering the interface between the gas layer and the liquid to be processed, the liquid to be processed in the diffuser header 2 can be easily and reliably drained through the plurality of air diffusers 3.

The lower limit of the length in the central axis direction of the diffuser header 2 is preferably 0.5 m, and more preferably 1.0 m. The upper limit of the length in the central axis direction is preferably 3 m, and more preferably 2 m. If the length in the central axis direction is less than the lower limit, it may not be usable for a large-sized filtration device. If the length in the central axis direction exceeds the upper limit, the amount of gas supplied to the plurality of diffuser tubes 3 becomes insufficient, and it may be difficult to sufficiently increase the cleaning efficiency.

The lower limit of the cross-sectional area perpendicular inner space to the central axis of the air diffuser header 2, preferably 15cm ^2, 40 cm ² is more preferable. As an upper limit of the cross-sectional area, 150 cm ² is preferable, and 120 cm ² is more preferable. If the cross-sectional area is less than the lower limit, it may be difficult to form the gas layer forming region inside the diffuser header 2, or the diffuser tube 3 disposed at a position relatively distant from the gas inlet 11. There is a risk that it will be difficult to sufficiently supply gas. If the cross-sectional area exceeds the upper limit, the air diffuser head 2 becomes too large, and it may be difficult to attach the air diffuser unit 1 to the filtration device.

The main component of the diffuser header 2 is not particularly limited, and metals such as stainless steel, steel, copper and aluminum, acrylic resin, polyethylene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin) ) And the like. The “main component” means a component having the highest content, for example, a component having a content of 50% by mass or more.

(Air diffuser)
The plurality of diffuser tubes 3 communicate with the diffuser header 2 and extend outward from the pair of side walls facing the diffuser header 2 in the opposite direction. Moreover, it is preferable that the plurality of diffuser tubes 3 extend from the opposed positions of the pair of side walls opposed to the diffuser header 2. The plurality of air diffusing tubes 3 have a central axis arranged in the horizontal direction.

The plurality of diffuser tubes 3 are formed in the same shape. In addition, it is preferable that the lowest positions h _{1 on} the inner surfaces of the plurality of diffusion tubes 3 are all the same, and the uppermost positions h _{3 on} the inner surfaces of the plurality of the diffusion tubes ₃ are all the same.

The plurality of air diffusion tubes 3 are preferably arranged at equal intervals in the direction of the central axis of the air diffusion head 2 from a pair of side walls opposed to the air diffusion head 2. The plurality of air diffusion tubes 3 are disposed at equal intervals in the central axis direction of the air diffusion head 2 from a pair of opposing side walls of the air diffusion head 2. The air diffusing tube 3 can be easily arranged, and thereby the cleaning effect of the plurality of filtration modules can be enhanced.

The lower limit of the number of the plurality of air diffusion tubes 3 extending from the respective side walls of the air diffusion head 2 can be appropriately changed according to the number of filtration modules provided in the filtration device. More preferred. As the upper limit of the number, for example, 40 is preferable and 30 is more preferable. The plurality of air diffusion tubes 3 are disposed between the plurality of filtration modules of the filtration device as described above, so that a pair of filtration modules adjacent to each air diffusion tube 3 in plan view (however, located on the outermost side). The air diffuser 3 disposed outside the filtration module is configured to be capable of cleaning a plurality of hollow fiber membranes of one adjacent filtration module). In this regard, if the number of the plurality of diffuser tubes 3 is less than the lower limit, the interval between the adjacent diffuser tubes 3 becomes too large, and the interval between the filtration module and the diffuser tube 3 in a plan view increases. There is a possibility that the cleaning effect of the plurality of hollow fiber membranes of the plurality of filtration modules cannot be sufficiently enhanced. On the contrary, when the number of the plurality of diffuser tubes 3 exceeds the above upper limit, the interval between the adjacent diffuser tubes 3 becomes too small and it is difficult to arrange the plurality of diffuser tubes 3 between the pair of adjacent filtration modules. There is a risk.

The lower limit of the interval between adjacent diffuser tubes 3 is preferably 20 mm, and more preferably 30 mm. As an upper limit of the said space | interval, 200 mm is preferable and 150 mm is more preferable. If the interval is less than the lower limit, the interval between adjacent diffuser tubes 3 becomes too small, and it may be difficult to dispose a plurality of diffuser tubes 3 between a pair of adjacent filtration modules. If the interval exceeds the upper limit, the interval between the filtration module and the air diffuser 3 in a plan view becomes too large, and the cleaning effect of the plurality of filtration modules may not be sufficiently improved.

As described above, the lowest position h _{1 on} the inner surface of the plurality of diffuser tubes 3 is close to the lowest position h _{2 on} the inner surface of the diffuser header 2 in the vertical direction. Further, the lowermost position h ₁ of the inner surface of the plurality of diffuser tubes 3 are either the lowest position h ₂ and peers of the inner surface of the air diffuser header 2, or air diffuser header 2 from the lowest position h ₂ of the inner surface Is also expensive. Specifically, the upper limit of the vertical distance between the lowest position h ₂ of the inner surface of the lowermost position h ₁ and aeration header 2 of the inner surface of the plurality of diffuser tubes 3, 10 mm are preferred, 6 mm, more preferably 3 mm is more preferable, and 0 mm is most preferable. When the vertical distance exceeds the upper limit, the non-processed liquid easily accumulates at a position lower than the lowest position h ₁ of the plurality of air diffusers 3 in the air diffuser header 2. When the gas is introduced into the air, the liquid level of the liquid to be processed in the diffuser header 2 may wave, and the gas may not be uniformly supplied to the plural diffuser tubes 3. The “lowermost position of the inner surface of the diffuser tube” means, for example, the position of the bottom surface when the inner surface of the diffuser tube has a horizontal bottom surface, and the lower inner surface of the diffuser tube is curved. Means the lowest position of the inner surface in the vertical direction. The “lowermost position of the inner surface of the diffuser header” is also the same as the lowest position of the inner surface of the diffuser pipe.

The vertical distance between the uppermost position of the inner surface of the plurality of diffusion tubes 3 and the uppermost position of the inner surface of the diffusion header 2 is the lowest position of the inner surfaces of the plurality of diffusion tubes 3 and the lowermost position of the inner surface of the diffusion header 2. It is preferable that it is larger than the vertical distance from the position. Aeration unit 1, vertical distance between the inner surface of the uppermost position h ₄ of the uppermost h ₃ and diffuser header of the inner surface of the plurality of diffuser tubes are lowest position h ₁ of the inner surface of the plurality of diffuser tubes 3 and by greater than the vertical distance between the lowest position h ₂ of the inner surface of the diffuser header, easy to form the gas layer above the inside air diffuser header 2 by the gas introduced into the air diffuser header 2. Therefore, by gradually lowering the interface between the gas layer and the liquid to be treated, it is easy to uniformly supply the gas to the plurality of diffuser tubes 3. It is possible to promote the uniform discharge of bubbles. Further, the vertical distance between the lowest position h ₁ and lowermost position h ₂ of the inner surface of the air diffuser header 2 of the inner surface of the plurality of diffuser tubes 3, the uppermost position h ₃ of the inner surface of the plurality of diffuser tubes 3 by less than the vertical distance between the uppermost position h ₄ of the inner surface of the air diffuser header 2, a plurality of liquid to be treated in the aeration header 2 by the interface between the gas layer and the liquid to be treated gradually lowered The liquid can be easily and reliably discharged through the air diffuser 3. The “uppermost position of the inner surface of the diffuser tube” means, for example, the position of this upper surface when the inner surface of the diffuser tube has a horizontal upper surface, and when the upper inner surface of the diffuser tube is curved. It means the uppermost position in the vertical direction of this inner surface. Further, “the uppermost position of the inner surface of the diffuser header” is the same as the uppermost position of the inner surface of the diffuser pipe.

The lower limit of the vertical distance between the uppermost position _{h 3} of the inner surface of the uppermost _{h 4} and a plurality of diffuser tubes 3 of the inner surface of the air diffuser header 2, 15 mm is preferable, 25 mm, and still more preferably 30 mm. If the vertical distance is less than the lower limit, it is difficult to sufficiently form a gas layer above the uppermost position h ₃ on the inner surface of the plurality of air diffusers 3 by the gas introduced from the gas inlet 11. is there. The upper limit of the vertical distance can be set to, for example, 50 mm from the viewpoint of reducing the size of the air diffusion head 2.

Each diffuser tube 3 is formed in a straight tube shape having both ends opened in the central axis direction. The cross-sectional shape perpendicular to the central axis direction of each air diffuser 3 is not particularly limited, but may be, for example, an annular shape or a square shape.

The lower limit of the inner diameter of each air diffuser 3 is preferably 6 mm, more preferably 10 mm, and even more preferably 15 mm. The upper limit of the inner diameter of each air diffuser 3 is preferably 70 mm, more preferably 60 mm, and even more preferably 50 mm. If the inner diameter of each air diffuser 3 is less than the lower limit, there is a possibility that gas cannot be sufficiently supplied to each air diffuser 3. On the contrary, if the inner diameter of each air diffuser 3 exceeds the above upper limit, the volume in the tube increases, and solids such as impurities may easily stay in the air diffuser 3. The inner diameter when the cross-sectional shape in the central axis direction of the inner surface of the air diffusing tube 3 is other than a circle means the inner diameter when converted to a perfect circle.

The lower limit of the average tube thickness of each air diffuser 3 is preferably 1 mm, more preferably 2 mm. The upper limit of the average tube thickness of each air diffuser 3 is preferably 6 mm, and more preferably 4 mm. If the average tube thickness of each air diffuser 3 is less than the lower limit, sufficient strength may not be obtained. If the average tube thickness of each air diffuser 3 exceeds the above upper limit, the outer diameter may become unnecessarily large.

The shape of the plurality of air diffusion holes 12 is not particularly limited, but a circular shape is preferable. As shown in FIGS. 1 and 2, the plurality of air diffusion holes 12 are preferably the same size and arranged at equal intervals in the central axis direction of each air diffusion tube 3. The air diffuser unit 1 has a plurality of air diffuser holes 12 arranged at equal intervals in the central axis direction of each air diffuser 3, while sending the gas supplied from the air diffuser header 2 to the front end side in the extending direction, It can discharge substantially uniformly along the central axis direction. The plurality of air diffusion holes 12 can be formed by, for example, laser processing.

Further, it is preferable that the centers of the plurality of air diffusion holes 12 are arranged so as to coincide with the vertical cross section including the central axis of each air diffusion tube 3. That is, it is preferable that the centers of the plurality of air diffusion holes 12 are included in a vertical section including the central axis of each air diffusion tube 3. Further, each air diffuser 3 preferably has no opening other than the air diffuser 12 on its peripheral surface. The diffuser unit 1 can continuously discharge the cleaning gas from the diffuser holes 12 while sending the gas into the pipe by arranging the diffuser holes 12 in this manner.

The lower limit of the average diameter of the plurality of air diffusion holes 12 is preferably 1 mm, and more preferably 2 mm. The upper limit of the average diameter of the plurality of air diffusion holes 12 is preferably 10 mm, and more preferably 8 mm. If the average diameter is less than the lower limit, bubbles may not be released sufficiently. On the other hand, when the average diameter exceeds the upper limit, the amount of bubbles released from each air diffuser 12 becomes too large, so that when the gas is supplied from the air diffuser header 2, this gas becomes the air diffuser header 2 side. There is a possibility that the amount of discharge from the front end side in the extending direction may not be sufficiently obtained due to excessive discharge from the air diffuser 12 disposed in the. In addition, the average diameter in case the diffuser hole 12 is other than a circle means the average diameter when converted into a perfect circle.

The lower limit of the average pitch (center-to-center distance) of the plurality of air diffusion holes 12 is preferably 10 mm, and more preferably 20 mm. The upper limit of the average pitch of the plurality of air diffusion holes 12 is preferably 150 mm, and more preferably 100 mm. If the average pitch is less than the lower limit, when gas is supplied from the diffuser header 2, the gas is excessively released from the diffuser holes 12 disposed on the diffuser header 2 side, and the leading end side in the extending direction There is a risk that a sufficient amount of release will not be obtained. When the average pitch exceeds the upper limit, there is a possibility that a region where gas is hardly supplied in the filtration module may be generated.

The main components of the air diffuser 3 include metals such as stainless steel, steel, copper and aluminum, and synthetic resins such as acrylic resin, polyethylene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer (ABS resin). Of these, polyvinyl chloride is preferable because of its excellent durability and relatively low cost.

(Cleaning gas)
The cleaning gas introduced into the diffuser unit 1 is required to have a specific gravity smaller than that of the liquid to be processed so that a gas layer can be formed above the diffuser header 2. The cleaning gas introduced into the air diffusion unit 1 is preferably an inert gas. Although it does not specifically limit as such gas, Typically, air is mentioned.

<Filtration device>
The filtration device 21 in FIGS. 4 and 5 is an immersion type filtration device. The filtration device 21 includes a plurality of filtration modules 22 having a plurality of hollow fiber membranes 31 and a gas supply module 23 that supplies bubbles from below the plurality of filtration modules 22. The gas supply module 23 includes the air diffusion unit 1 shown in FIG. The plurality of filtration modules 22 and the gas supply module 23 are integrally held by being connected to the frame 24.

Since the filtration device 21 includes the air diffusion unit 1, it is possible to equalize the amount of air bubbles released from the plurality of air diffusion holes 12 of the plurality of air diffusion tubes 3 as described above. The homogenization of the cleaning effect of 22 can be achieved.

(Filtration module)
Each filtration module 22 includes a plurality of hollow fiber membranes 31, a rod-like upper holding member 32 that holds the upper ends of the plurality of hollow fiber membranes 31, and a rod-like shape that holds the lower ends of the plurality of hollow fiber membranes 31. Lower holding member 33. The plurality of hollow fiber membranes 31 are aligned in the vertical direction. The plurality of hollow fiber membranes 31 are connected to substantially the entire lower surface of the upper holding member 32 and the upper surface of the lower holding member 33. With this configuration, each filtration module 22 has a thickness (the length in the central axis direction of the upper holding member 32 and the lower holding member 33) as a whole and the thickness (the central axis direction of the upper holding member 32 and the lower holding member 33). It is formed in a substantially rectangular parallelepiped shape with a small vertical horizontal length). The upper holding member 32 is formed in a hollow shape. The upper holding member 32 is connected to a discharge mechanism (not shown) that discharges the processed liquid filtered by the filtration module 22. Thereby, the filtration apparatus 21 is comprised so that the processed liquid which permeate | transmitted the several hollow fiber membrane 31 of the several filtration module 22 can be discharged | emitted via a discharge mechanism.

The plurality of filtration modules 22 are arranged in two rows in front view as shown in FIG. Moreover, the several filtration module 22 is arrange | positioned in parallel at equal intervals in each row | line | column, as shown in FIG. Specifically, in the filtration device 21, a pair of filtration modules 22 are arranged in two rows so that edges in the width direction are adjacent to each other, and a plurality of filtration modules 22 are opposed in the thickness direction in each row. They are arranged at equal intervals.

The hollow fiber membrane 31 is formed by tubularly forming a porous membrane that permeates water while preventing permeation of impurities contained in the liquid to be treated. For example, a hollow fiber membrane 31 that uses a thermoplastic resin as a main component is used. Can do. The average length of the bundle of a plurality of hollow fiber membranes 31 in each filtration module 22 in the width direction of the filtration module 22 can be, for example, 300 mm or more and 1200 mm or less. The average length of the bundle of a plurality of hollow fiber membranes 31 in each filtration module 22 in the thickness direction of the filtration module 22 may be, for example, 10 mm or more and 100 mm or less. The average length of the plurality of hollow fiber membranes 31 between the lower end of the upper holding member 32 and the upper end of the lower holding member 33 can be, for example, 1 m or more and 6 m or less.

(Gas supply module)
The gas supply module 23 includes an air diffusion unit 1 and a gas pressure feeding unit (not shown) that supplies gas to the gas introduction port of the air diffusion header of the air diffusion unit 1. The gas pressure feeding unit is not particularly limited, and examples thereof include a known blower and a compressor.

The air diffusion unit 1 discharges bubbles from below the plurality of filtration modules 22 toward the plurality of hollow fiber membranes 31 of the plurality of filtration modules 22. The air diffusion unit 1 is arranged such that the central axis of the air diffusion header coincides with the center between the rows of the plurality of filtration modules 22 arranged in two rows in a plan view. Further, the air diffusion unit 1 is arranged such that a plurality of air diffusion tubes 3 are positioned between adjacent filtration modules 22 in each row in a plan view. Further, in the air diffuser unit 1, each pair of air diffuser tubes 3 located at both ends in the central axis direction of the air diffuser header is located outside in a plan view of each pair of filtration modules 22 located on the outermost side in each row. Arranged. It is preferable that the space | interval in planar view of the several filtration module 22 and the several diffuser tube 3 is equal.

[Second Embodiment]
<Filtration device>
The filtration device 41 in FIG. 6 is an immersion type filtration device. The filtration device 41 includes a plurality of filtration modules 22 having a plurality of hollow fiber membranes 31 and a gas supply module 43 that supplies air bubbles from below the plurality of filtration modules 22. The plurality of filtration modules 22 in the filtration device 41 are the same as the plurality of filtration modules 22 of the filtration device 21 in FIGS.

(Gas supply module)
As shown in FIGS. 6 and 7, the gas supply module 43 includes a plurality of intermittent bubble generation units disposed vertically above the air diffuser unit 1 of FIG. 1 and the air diffuser holes 12 of the air diffuser unit 1. 44 and a gas pumping unit (not shown) for supplying gas to the gas inlet of the air diffuser head of the air diffuser unit 1. As the gas pressure feeding unit, the same gas pressure feeding unit as that of the filtration device 21 of FIGS. 4 and 5 can be adopted. That is, the filtration device 41 has the same configuration as the filtration device 21 of FIGS. 4 and 5 except that it has a plurality of intermittent bubble generation units 44.

Since the gas supply module 43 includes a plurality of intermittent bubble generation units 44 disposed vertically above the plurality of air diffusion holes 12, the filtration device 41 can discharge relatively large bubbles. By increasing the energy of the bubbles, the cleaning effect on the surface of the plurality of hollow fiber membranes 31 can be further enhanced. In addition, if there are diffused holes with a small amount of released pores, the diameter of bubbles discharged from the intermittent bubble generating unit disposed vertically above the diffused holes is reduced and the discharge interval is extended, thereby improving the cleaning effect. However, since the filtering device 41 can discharge bubbles uniformly from the plurality of air diffusion holes 12, the intermittent bubble generation unit 44 can easily and reliably improve the cleaning effect. .

(Intermittent bubble generation unit 44)
The intermittent bubble generating unit 44 is arranged in a one-to-one correspondence above the plurality of air diffusion holes 12 of the air diffusion unit 1. As shown in FIG. 8, the intermittent bubble generating unit 44 includes a base 51 and a protruding portion 52 that protrudes above the base 51 (upward in the Z direction in FIG. 8). As shown in FIG. 9, the protruding portion 52 has a front wall 52 a and a rear wall 52 b facing each other, and a rear surface (an outer surface of the rear wall 52 b) is formed flush with the rear surface of the base 51. The intermittent bubble generating unit 44 has an opening 53 below the base 51. Further, the intermittent bubble generating unit 44 is provided with a discharge port 54 at the upper end of the protruding portion 52. The intermittent bubble generating unit 44 is configured to be capable of intermittently discharging upward from the discharge port 54 after introducing the bubbles released from the diffuser holes 12 through the opening 53. In the intermittent bubble generation unit 44, “front” means the positive side in the X direction (front side of the paper) in FIG. 8, and “rear” means the negative side in the X direction (depth side of the paper), “Left” means the positive side in the Y direction, and “right” is defined for convenience as meaning the negative side in the Y direction. The specific configuration of the intermittent bubble generating unit 44 is specified. Not what you want.

9 to FIG. 11, the specific configuration of the intermittent bubble generating unit 44 will be described in detail. The intermittent bubble generation unit 44 includes a gas introduction chamber 55, a gas induction chamber 56, and a gas discharge chamber 57. The intermittent bubble generating unit 44 has an opening 53 formed at the lower end of the gas introduction chamber 55. The intermittent bubble generating unit 44 has a discharge port 54 formed at the upper end of the gas discharge chamber 57.

The gas introduction chamber 55 is formed in a rectangular parallelepiped shape in the base 51. The gas introduction chamber 55 is partitioned from a gas induction chamber 56 and a gas discharge chamber 57 by a partition wall 58. The partition wall 58 continuously extends downward from the lower end of the front wall 52a of the protrusion 52. An opening 60 is formed in the upper end portion of the partition wall 58 that partitions the gas introduction chamber 55 and the gas induction chamber 56. Thereby, the gas introduction chamber 55 and the gas induction chamber 56 communicate with each other through the opening 60.

The gas induction chamber 56 is formed in a rectangular parallelepiped shape in the base 51. The gas induction chamber 56 is formed on the left side (Y direction positive side) of the protrusion 52 in plan view. The gas induction chamber 56 is partitioned from the gas introduction chamber 55 by the partition wall 58 and is partitioned from the gas discharge chamber 57 by the partition wall 59. An opening 61 is formed in the lower end portion of the partition wall 59 that partitions the gas induction chamber 56 and the gas discharge chamber 57. Thereby, the gas induction chamber 56 and the gas discharge chamber 57 communicate with each other through the opening 61.

The gas discharge chamber 57 is formed in a rectangular parallelepiped shape so as to communicate with the inside of the base portion 51 and the protruding portion 52. The gas discharge chamber 57 is partitioned from the gas introduction chamber 55 by the partition wall 58 and is partitioned from the gas induction chamber 56 by the partition wall 59.

Since the intermittent bubble generating unit 44 has the above-described configuration, the gas introduced into the gas introduction chamber 55 first moves to the upper portion of the gas introduction chamber 55. The gas moved to the upper part is introduced into the gas induction chamber 56 through the opening 60. As a result, the gas introduced into the gas introduction chamber 55 is stored near the upper ends of the gas introduction chamber 55 and the gas induction chamber 56. Thereafter, when the gas is further introduced into the gas introduction chamber 55, the interface between the gas and the liquid to be processed is divided into the gas introduction chamber 55 and the gas induction chamber 56, respectively, while maintaining the same horizontal level position. Move to. When the gas in the gas induction chamber 56 exceeds a predetermined amount, the gas is guided from the opening 61 to the gas discharge chamber 57, and relatively large bubbles are intermittently discharged from the discharge port 54. In the present embodiment, the configuration in which one gas guide chamber is formed on the left side of the projecting portion in plan view is described. However, the gas guide chamber may be formed on the right side of the projecting portion. A pair may be formed on the left and right, or may be formed in the center.

As shown in FIG. 7, the gas supply module 43 includes a plurality of intermittent bubble generation units 44 having the above-described configuration, in parallel with the central axis direction of the air diffusion tube 3 with the left side wall and the right side wall facing each other. It is arranged continuously. Further, in the gas supply module 43, each air diffuser 12 of each air diffuser 3 is arranged vertically below the opening 53 of each intermittent bubble generating unit 44.

In the filtering device 41, as described above, the diffuser header forms a gas layer with the gas introduced from the gas introduction port above the uppermost position h ₃ on the inner surface of the multiple diffuser tubes _3. It is preferable to have a gas layer forming region for the purpose. However, when the diffuser header has such a gas layer forming region, the vertical spacing between the plurality of diffuser holes 12 and the plurality of filtration modules 22 becomes too large, and the bubbles discharged from the diffuser holes 12 May not be accurately introduced between the plurality of filtration modules 22. In this regard, the filtering device 41 disposes a plurality of intermittent bubble generation units 44 vertically above the plurality of air diffusion holes 12, thereby removing bubbles released from the air diffusion holes 12 by the intermittent bubble generation units 44. Can guide. Accordingly, the filtration device 41 includes the gas supply module 43 having the plurality of intermittent bubble generation units 44, thereby increasing the energy of bubbles released from the plurality of air diffusion holes 12, and more reliably filtering the bubbles. It can be introduced between the modules 22.

The upper limit of the vertical distance between the plurality of air diffusion holes 12 and the openings 53 of the plurality of intermittent bubble generation units 44 is preferably 20 mm, and more preferably 15 mm. If the vertical distance exceeds the upper limit, it may be difficult to reliably introduce bubbles released from the plurality of air diffusion holes 12 into the opening 53. Although it does not specifically limit as a minimum of the said perpendicular distance, For example, it can be 1 mm.

In addition, when the diffuser header has a gas layer forming region, the filtration device 41 has an air diffuser in plan view because the upper outer surface of the diffuser header protrudes higher than the upper outer surface of the plurality of diffuser tubes 3. There is a possibility that it is difficult to dispose the intermittent bubble generating unit 44 in a region overlapping with the header. In this respect, the filtering device 41 has an inverted T-shaped outer shape perpendicular to the central axis of the diffuser header, thereby providing a gas layer formation region in the diffuser header and intermittently on both sides of the protruding portion. A static bubble generating unit 44 can be provided. Therefore, according to such a configuration, even if the air diffuser 12 is provided in a position close to the air diffuser header, the intermittent bubble generating unit 44 can be disposed at a position corresponding to the air diffuser 12, thereby sufficient cleaning. The effect can be improved.

[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 meaning and scope equivalent to the scope of the claims.

For example, in the diffuser unit, a plurality of diffuser tubes do not need to extend from a pair of side walls of the diffuser header, and a plurality of diffuser tubes may extend from only one side wall. Each one aeration tube may extend.

The gas inlet of the diffuser header does not necessarily have to be provided above the uppermost position on the inner surface of the plurality of diffuser tubes. For example, in the air diffusion unit, the gas inlet may be formed in the lower part of the end wall on the one end side in the central axis direction of the air diffusion header. In addition, the gas inlet does not necessarily have to be formed at one end side in the central axis direction of the diffuser header, for example, it may be formed at both ends in the central axis direction of the diffuser header. You may form in the center of an axial direction.

¡Multiple diffusers do not necessarily have the same shape. For example, the plurality of air diffusers may have different lengths in the central axis direction and may have different diameters. Further, the lowermost position and the uppermost position of the inner surfaces of the plurality of diffusion tubes may be different from each other.

The air diffuser unit may have a tubular solid content discharge section that is provided continuously at the tip edge of the air diffuser and is inclined downward from the central axis direction of the air diffuser. Since the air diffusion unit has the solid content discharge unit, the solid content that has entered the air diffusion tube can be smoothly discharged from the outlet of the solid content discharge unit (the end opposite to the air diffusion tube) with the pressure of the gas. . As a result, the aeration unit can prevent the solid content from staying without disturbing the supply of the cleaning gas to the plurality of filtration modules.

The diffuser header may have a gas merging pipe that is communicated so as to integrate the ends in the extending direction of a plurality of diffuser pipes and is disposed in the horizontal direction. The diffuser header has such a gas merging tube, and the gas in each diffusing tube is integrated by the gas merging tube to improve the uniformity of pressure in the plurality of diffusing tubes. Uniformity of the amount of bubbles released from the pores can be promoted.

The specific configuration of the intermittent bubble generation unit is not limited to the above-described configuration, and various configurations capable of intermittently discharging bubbles can be employed.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.

[Example]
[No. 1]
A straight tubular diffuser header having a gas introduction port into which the cleaning gas is introduced and having a central axis disposed in the horizontal direction, and a pair of side walls opposed to the diffuser header extending in the horizontal direction. An air diffusing unit comprising a plurality of straight tubular air diffusing tubes having air diffusing holes was prepared. As the diffuser header, one in which the gas inlet was formed above the uppermost position of the inner surfaces of the diffuser holes on one end side in the central axis direction of the diffuser header was used. The length of the diffuser header in the central axis direction is 1.74 m, and the number of diffuser tubes extending from each side wall is 25 (50 in total). These diffuser tubes are arranged at equal intervals on each side wall. It had been. Further, the length of each diffuser tube in the central axis direction was 0.8 m, and each diffuser tube was provided with six diffuser holes at equal intervals. Further, the vertical distance between the lowest position of the inner surface of the plurality of diffuser tubes and the lowest position of the inner surface of the diffuser header is 6 mm, and the uppermost position of the inner surface of the diffuser header and the inner surfaces of the plurality of diffuser tubes are The vertical distance from the uppermost position was 40 mm, and the cross-sectional area of the internal space in the direction perpendicular to the central axis direction of the diffuser header was 90 cm ² .

This aeration unit was immersed in the water tank so that the uppermost position of the plurality of aeration pipes had a water depth of 10 cm. Air was introduced from the gas inlet of this air diffusion unit so that the air volume per air hole was 23.3 L / min.

[Comparative example]
[No. 2]
A straight tubular diffuser header having a gas introduction port into which the cleaning gas is introduced and having a central axis disposed in the horizontal direction, and a pair of side walls opposed to the diffuser header extending in the horizontal direction. An air diffusing unit comprising a plurality of straight tubular air diffusing tubes having air diffusing holes was prepared. As the diffuser header, one in which the gas inlet was formed above the uppermost position of the inner surfaces of the diffuser holes on one end side in the central axis direction of the diffuser header was used. The length of the diffuser header in the central axis direction, the number of diffuser tubes extending from each side wall, the positions of these diffuser tubes, and the specific configuration of the multiple diffuser tubes are No. Same as 1. The vertical distance between the lowest position of the inner surfaces of the plurality of diffuser tubes and the lowest position of the inner surface of the diffuser header is 116 mm, and the uppermost position of the inner surfaces of the diffuser header and the uppermost position of the inner surfaces of the multiple diffuser tubes The cross-sectional area of the inner space in the direction perpendicular to the central axis direction of the diffuser header was 90 cm ² .

<Aeration>
No. 1, it was confirmed visually that bubbles were released from all the air holes. As a result, no. It was found that the air diffusing unit used in No. 1 can achieve uniform discharge of bubbles from a plurality of air diffusing holes of a plurality of air diffusing tubes. In contrast, no. In No. 2, it was not possible to visually confirm the release of bubbles from the plurality of diffuser holes of the plurality of diffuser tubes disposed at positions away from the gas inlet. Specifically, no. In 2, the release of bubbles could not be confirmed in about half of the air holes.

DESCRIPTION OF SYMBOLS 1 Air diffuser unit 2 Air diffuser header 3 Air diffuser pipe 11 Gas inlet 12

Air diffuser hole

21, 41 Filtration device 22

Filtration module

23, 43 Gas supply module 24 Frame 31 Hollow fiber membrane 32 Upper holding member 33 Lower holding member 44 Intermittent bubble Generating unit
51 Base 52 Projection

52a Front wall

52b Rear wall

53, 60, 61 Open 54 Discharge port 55 Gas introduction chamber 56 Gas induction chamber 57

Gas discharge chamber

58, 59 Partition wall h ₁ Lowermost position of inner surface of air diffuser h ₂ Scatter The lowest position of the inner surface of the air header h ₃ The uppermost position of the inner surface of the air diffuser h ₄ The uppermost position of the inner surface of the air diffuser header

Claims

An air diffuser unit for supplying a cleaning gas for an immersion type filtration device,
A straight tubular diffuser header having a gas inlet through which the cleaning gas is introduced, the central axis being disposed in a horizontal direction;
A plurality of straight tubular air diffusers that communicate with the air diffuser header, extend from the side walls of the air diffuser header, and have a plurality of air diffuser holes;
A diffuser unit in which the lowest position of the inner surfaces of the plurality of diffuser tubes is close to the lowest position of the inner surface of the diffuser header in the vertical direction.
The vertical distance between the uppermost position of the inner surfaces of the plurality of diffuser tubes and the uppermost position of the inner surfaces of the diffuser headers is the lowest position of the inner surfaces of the diffuser tubes and the lowest position of the inner surfaces of the diffuser headers. The aeration unit according to claim 1, wherein the aeration unit is larger than the vertical distance.
The air diffusion unit according to claim 2, wherein the gas introduction port is provided above the uppermost position on the inner surface of the plurality of air diffusion tubes.
An immersion type filtration device comprising a plurality of filtration modules having a plurality of hollow fiber membranes, and a gas supply module for supplying bubbles from below the plurality of filtration modules,
A filtration apparatus provided with the aeration unit according to claim 1, claim 2 or claim 3, wherein the gas supply module.
The filtration device according to claim 4, wherein the gas supply module further includes a plurality of intermittent bubble generation units disposed vertically above the plurality of air diffusion holes.