TW201641151A - Filtration device - Google Patents

Abstract

The filtration device of one embodiment of the present invention comprises: one or more filtration modules having a plurality of vertically extending hollow fiber membranes and also having a pair of holding members for affixing the upper and lower ends of the plurality of hollow fiber membranes; and one or more cleaning modules for supplying air bubbles from below the filtration module. The lower holding member is disposed offset from the upper holding member in a plan view.

Description

filter

This invention relates to filtration devices.

Conventionally, 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 bundled together is used. In the filter module, a pressure is formed on the outer peripheral surface side of the hollow fiber membrane to allow the liquid to be treated to penetrate the inner peripheral surface side of the hollow fiber membrane, and the pressure is applied by the impregnation pressure or the inner peripheral surface side. An impregnation type in which the liquid to be treated is penetrated to the inner peripheral surface side, and an internal pressure type in which the inner peripheral surface side of the hollow fiber membrane is formed to have a high pressure and the liquid to be treated penetrates to the outer peripheral surface side of the hollow fiber membrane.

The external pressure type and the immersion type of the above filter module, the surface of each hollow fiber film will be contaminated due to the attachment of the substance contained in the liquid to be treated, if used, if If it is not cleaned, the filtering capacity will decrease. Therefore, the cleaning method used in the prior art is an air friction cleaning method in which air bubbles are sent from the lower side of the filter module, the air bubbles are rubbed against the surface of each hollow fiber film, and each hollow fiber film is vibrated to remove the deposits. Reference Japan Special Opening 2010-42329 Bulletin).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP-A-2010-42329

In general, in order to keep the surface of the hollow fiber membrane clean, the bubbles for cleaning the surface of the hollow fiber membrane are continuously supplied. Therefore, if the cleaning efficiency of the bubble on the surface of the hollow fiber membrane is lowered, in order to maintain the filtration ability, the energy required for the supply of the cleaning bubble is inevitably required to be increased, which may cause an increase in the filtration cost. As one of the countermeasures for reducing the cost of such filtration, although it is conceivable to form a plurality of filter modules in a longitudinal direction, the bubble is formed at the holding member of the hollow fiber membrane (the connection portion of the filter module). The diffusion causes the bubbles to not contact the surface of the hollow fiber membrane located at the upper portion, and as a result, there is a concern that the cleaning efficiency is lowered.

The present invention has been developed in view of the above-described circumstances, and provides a filtration device having excellent cleaning efficiency on the surface of a hollow fiber membrane as a technical problem of the present invention.

An embodiment of the present invention for solving the above problems The filter device comprises: a plurality of hollow fiber membranes having a plurality of hollow fiber membranes pulled up and a plurality of filter modules for fixing the upper and lower ends of the plurality of hollow fiber membranes; and the plurality of filter modules; A filter device for supplying one of the air bubbles or a plurality of cleaning modules is disposed below the module, and the holding member on the lower side is disposed so as to be offset from the upper holding member when viewed from a plan view.

A filter device according to an embodiment of the present invention, wherein the cleaning efficiency of the surface of the empty film is excellent.

1‧‧‧Filter device

2‧‧‧Filter module

3‧‧‧Frame

4‧‧‧ Cleaning module

5‧‧‧Discharge agencies

6‧‧‧ hollow fiber membrane

7‧‧‧Upper holding member

7a‧‧‧Draining nozzle

8‧‧‧Bottom holding member

9‧‧‧ bubble spit

10‧‧‧Air supply pipe

11‧‧‧Water collection piping

12‧‧‧ suction pump

C ₁ , C ₂ ‧ ‧ center of gravity

L ₁ ‧‧‧width of the hollow fiber membrane bundle in the Y direction

L ₂ ‧‧‧width of the hollow fiber membrane bundle in the X direction

P‧‧‧with spacing

S‧‧‧ offset

T‧‧‧ filter tank

W‧‧‧Width

Fig. 1 is a schematic view showing a filtration system having a filtration device according to an embodiment of the present invention.

Fig. 2 is a schematic plan view showing a filter module in a state held by the filter device of Fig. 1.

Fig. 3 is a schematic perspective view showing the filter module of Fig. 2.

[Description of Embodiments of the Present Invention]

A filter device according to an embodiment of the present invention includes: a plurality of hollow fiber membranes having a top-down pull-down and a plurality of hollow fiber membranes One or more filter modules of one of the holding members are fixed at the upper and lower ends; one or a plurality of filter modules of the cleaning module are supplied from below the filter module, and the holding members on the lower side are It is arranged such that when viewed from a plan view, the holding member is offset from the upper side.

In the filter device, the lower holding member is disposed so as to be offset from the upper holding member when viewed from a plan view, so that the bubble rises in the vertical direction around the lower holding member. It is easy to collide with the hollow fiber membrane, and the cleaning efficiency of cleaning the hollow fiber membrane by the bubble is excellent. Therefore, the filtering device can relatively easily maintain the filtering ability.

The filter module has a structure in which a plurality of hollow fiber membranes are arranged in a curtain shape in a rod-shaped holding member, and the plurality of filter modules are arranged in parallel and at equal intervals, and the plurality of filter modules are arranged in parallel The lower holding member may be shifted from the axial direction and the vertical direction by a predetermined offset from the plan view. Therefore, the lower holding member of the plurality of filter modules is offset from the upper holding member in the axial direction and the vertical direction by a predetermined distance as viewed in a plan view, thereby eliminating the need to increase the size of the filter module. By arranging the pitch, it is possible to reduce the length of the portion of the hollow fiber film that falls within the shadow of the lower holding member when viewed from below. In this way, the size of the apparatus can be suppressed, and the amount of air required for cleaning the hollow fiber membrane can be reduced, thereby improving the cleaning efficiency.

The offset amount is preferably 50% or more and 200% or less of the arrangement pitch of the plurality of filter modules. By taking the above offset By setting it within the above range, it is possible to reliably prevent the decrease in volumetric efficiency and to improve the cleaning efficiency of the hollow fiber membrane.

The bubble discharge port of the cleaning module may be disposed in a gap between the holding members on the lower side when viewed from a plan view. The air bubble discharge port of the cleaning module is disposed in a gap between the lower holding members when viewed from a plan view, and thus the air bubbles that are supplied by the bubble discharge port of the cleaning module rise. It will efficiently collide with the hollow fiber film through the gap of the holding member on the lower side. Therefore, the cleaning efficiency of the hollow fiber film can be more surely improved.

The plurality of hollow fiber membranes disposed between the pair of holding members may have a degree of slack. Therefore, the plurality of hollow fiber membranes disposed between the pair of holding members are swayable by the hollow fiber membrane by retaining the slack, so that the bubbles easily enter the inside of the hollow fiber bundle. The inner hollow fiber membrane can be easily cleaned, and the vibration of the hollow fiber membrane can promote the cleaning effect.

The hollow fiber membrane may be made of polytetrafluoroethylene as a main component. Therefore, the hollow fiber membrane has polytetrafluoroethylene as a main component, whereby the hollow fiber membrane can have sufficient mechanical strength and can withstand strong friction of the bubbles, thereby optimizing the supply amount of the bubbles. Can promote the cleaning effect.

Here, the term "when viewed from a plan view" means the state of the state when viewed from the up and down direction. The so-called "shift" refers to the fact that the position of the center of gravity is staggered. In addition, the term "stick shape" means: an elongated shape, specifically, a long axis direction The length is four times or more the maximum width (maximum diameter) in the direction perpendicular to the long axis direction. Further, the term "disposing a plurality of hollow fiber membranes into a curtain shape" means: arranging a plurality of hollow fiber membranes as: a partition wall that can separate one direction from another direction . Further, the term "the hollow fiber film retaining slack" means a state in which the hollow fiber film fixed between the pair of holding members is not stretched, specifically, if a pair of holding members are used When the portion of the hollow fiber membrane is regarded as an effective portion, the length of the effective portion (the length of the hollow fiber membrane along the axial direction) is larger than the interval between the pair of holding members.

[Detailed Description of Embodiments of the Present Invention]

Embodiments of the filter device of the present invention will be described in detail below with reference to the drawings.

The filtration system of Fig. 1 includes a filtration tank T for storing a liquid to be treated to be filtered, and a filtration device 1 according to an embodiment of the present invention disposed in the filtration tank T. Hereinafter, the vertical direction in the first drawing will be referred to as the Z direction, the left and right direction will be referred to as the X direction, and the direction toward the depth of the paper surface will be referred to as the Y direction.

[filter tank]

The filter tank T is used to store the liquid to be treated, and the filter device 1 is immersed in the filter tank T. The material of the filter tank T can be, for example, resin, metal, concrete, or the like.

〔filter〕

The filter device 1 includes: a plurality of filter modules 2; a frame 3 for holding the plurality of filter modules 2; a cleaning module 4 for supplying bubbles from below the filter module 2; and a filter module 2 The filtered treated liquid is discharged to the discharge mechanism 5.

<Filter Module>

The filter module 2 is provided with a plurality of hollow fiber membranes 6 that are aligned in the upper and lower (Z direction or near Z direction), and an upper end upper holding member 7 for fixing the plurality of hollow fiber membranes 6; The holding member 7 constitutes a pair of lower end lower side holding members 8 for fixing the plurality of hollow fiber membranes 6.

For example, as shown in FIG. 2, when the filter module 2 is held by the frame 3, the lower holding member 8 is disposed so as to be offset from the upper holding member 7 when viewed from a plan view. . In other words, the filter module 2 is disposed such that the center of gravity C ₁ of the projected shape of the upper holding member 7 and the center of gravity C ₂ of the projected shape of the lower holding member 8 are viewed in the X direction or in the X direction. The position is shifted in the Y direction. Thereby, for example, as shown in FIG. 1, the extending direction of the plurality of hollow fiber membranes 6 does not completely coincide with the Z direction, but is inclined at least partially in the X direction or the Y direction.

In the filter device 1, since the lower holding member 8 is disposed so as to be offset from the upper holding member 7 when viewed from a plan view, it is held along the lower side as shown in Fig. 1 . Week of member 8 The air bubbles rising in the vertical direction easily collide with the hollow fiber film 6, and the cleaning efficiency of cleaning the hollow fiber film 6 by the air bubbles is excellent. Therefore, the filter device 1 can maintain the filtration ability relatively easily.

In the plurality of filter modules 2 in the filter device 1, for example, as shown in FIG. 3, the upper holding member 7 and the lower holding member 8 are formed in an elongated rod shape in the Y direction, and along the axis thereof. The direction (long-axis direction) is preferably such that a plurality of hollow fiber membranes 6 are arranged in a curtain shape. Therefore, by arranging the plurality of hollow fiber membranes 6 in a curtain shape, the bubbles can enter the center of the bundle of the hollow fiber membrane 6 relatively easily in the X direction in which the thickness of the bundle of the hollow fiber membranes 6 becomes smaller. Therefore, the cleaning efficiency achieved by the cleaning module 4 is excellent.

In the filter device 1, the plurality of hollow fiber membranes 6 of the respective filter modules 2 may be held in an arrangement different from the curtain shape. In a specific example, the planar shape of the upper holding member 7 and the lower holding member 8 and the bundle of the hollow fiber membranes 6 held by the upper holding member 7 and the lower holding member 8 may be collectively collected in the XY. The cross-sectional shape on the plane is formed such that the width in the X direction is very close to the width in the Y direction.

Further, in the filter device 1, the plurality of filter modules 2 are parallel and equally spaced at a constant arrangement pitch P (distance between the centers of the upper holding members 7) as shown in Fig. 2; The match is set to be good. In other words, the plurality of filter modules 2 are arranged such that the axes of the upper holding member 7 and the lower holding member 8 are kept parallel and at equal intervals, and are arranged in the X direction, and are held on the frame 3, that is, can.

Further, in the filter device 1, the lower holding member 8 is perpendicular to the axial direction (Y direction) of the lower holding member 8 at the same distance (offset amount S) with respect to the upper holding member 7. It is better to make a shift in the direction (X direction). As shown in FIG. 2, by setting the offset amount S constant, even if the arrangement pitch P of the plurality of filter modules 2 is reduced, the lower holding members 8 can be prevented from interfering with each other.

The lower limit of the arrangement pitch P of the filter module 2 is preferably 1.1 times the average width W of the lower holding member 8 when viewed in a plan view, and more preferably 1.2 times. On the other hand, the upper limit of the arrangement pitch P is preferably 5 times the average width W of the lower side holding member 8, and more preferably 2 times. When the arrangement pitch P of the filter module 2 does not reach the above lower limit, the amount of bubbles that can be supplied from the lower holding member 8 to the hollow fiber membrane 6 may be insufficient. On the other hand, if the arrangement pitch P of the filter module 2 exceeds the above upper limit, the filter device 1 may become excessively large.

The lower limit of the offset amount S of the lower holding member 8 is preferably 30% of the arrangement pitch P of the filter module 2, and more preferably 50%. On the other hand, the upper limit of the offset amount S of the lower holding member 8 is preferably 200% of the arrangement pitch P of the filter module 2, and more preferably 150%. If the offset amount S of the lower holding member 8 does not reach the above lower limit, the air bubbles supplied from the lower holding member 8 may fail to sufficiently collide with the hollow fiber film 6 to pass through the filter module 2. Between the worries. On the other hand, if the offset amount S of the lower holding member 8 exceeds the above upper limit, the inclination of the hollow fiber film 6 becomes too large, so that the bubble does not rise along the bundle of the hollow fiber film 6, There will be a fear that the bubble is not supplied to a part of the longitudinal direction of the hollow fiber film 6.

Further, when the filter module 2 is held by the frame 3, the plurality of hollow fiber membranes 6 disposed between the pair of holding members are preferably provided with a slack. Specifically, the average effective length of the hollow fiber membrane 6 is larger than: the average distance between both ends of the effective portion (that is, the center and the lower surface of the lower surface of the portion of the upper holding member 7 that holds the hollow fiber membrane 6 It is preferable that the upward force generated by the tension of the hollow fiber film 6 is applied to the lower holding member 8 by the distance between the centers of the upper holding members 8 that hold the upper surface of the portion of the hollow fiber film 6.

Therefore, by keeping the hollow fiber film 6 relaxed, the hollow fiber film 6 can be easily oscillated, so that the air bubbles can easily enter the inside of the bundle of the hollow fiber film 6, and the vibration when the hollow fiber film 6 is oscillated can be used. Promote cleaning results. Further, since the hollow fiber film 6 is kept relaxed, the upper portion of the hollow fiber film 6 is suspended in a slightly vertical direction, and the lower portion of the hollow fiber film 6 is maintained in a state of being largely inclined. Therefore, the bubble which has risen by the gap of the lower holding member 8 will be able to impinge on the portion of the hollow fiber film 6 which is closer to the lower holding member 8, and the bubble which hits the hollow fiber film 6 is easily along the hollow. The upper portion of the yarn film 6 rises.

If the hollow fiber membrane 6 is in a state of tension, the effective portion of the hollow fiber membrane 6 (the portion between the upper holding member 7 and the lower holding member 8) will form a nearly linear extending state. On the other hand, if the hollow fiber film 6 has slack, the hollow fiber film 6 will be formed in a relaxed state from the straight line connecting the both ends of the effective portion thereof. because Therefore, the magnitude of the slack of the hollow fiber membrane 6 can be a ratio of the effective length of the hollow fiber membrane 6 to the linear distance between the both ends of the effective portion of the hollow fiber membrane 6 (for a simple example) This is expressed as the ratio of the length of the arc to the length of the chord when the effective portion of the hollow fiber membrane 6 is bent into an arc shape. The lower limit of the ratio of the average effective length of the average linear distance between the both ends of the effective portion of the hollow fiber membrane 6 is preferably 1.01, more preferably 1.02. On the other hand, the upper limit of the ratio of the average effective length of the average straight line distance between both ends of the effective portion of the hollow fiber membrane 6 is preferably 1.2, more preferably 1.1. The ratio of the average effective length of the average linear distance between the both ends of the effective portion of the hollow fiber membrane 6 is small, and if the lower limit is not reached, the amount of swing of the hollow fiber membrane 6 is small, and there will be: The bubbles sufficiently enter the inside of the bundle of the hollow fiber membranes 6 and the cleaning effect promoted by the vibration of the hollow fiber membrane 6 cannot be sufficiently obtained. On the contrary, with respect to the ratio of the average effective length of the average linear distance between both ends of the effective portion of the hollow fiber membrane 6, if the above upper limit is exceeded, the hollow fiber membranes 6 will be intertwined with each other to hinder the cleaning effect. consider.

<Cleaning Module>

The cleaning module 4 is disposed below the filter module 2 as shown in FIG. 1 and has a plurality of bubble discharge ports 9 for discharging air bubbles at positions corresponding to the respective filter modules 2. . In this case, the plurality of bubble discharge ports 9 are arranged in the axial direction of the upper holding member 7 and the lower holding member 8 of the filter module 2 as shown in Fig. 3 . It is kept parallel and is set such that a column corresponding to each filter module 2 can be formed.

The row of the bubble discharge ports 9 is disposed relative to the lower holding member 8 of the corresponding filter module 2 in a direction in which the lower holding member 8 is biased toward the upper holding member 7 as viewed in a plan view. The position on the opposite side is preferred. The rows of the bubble discharge ports 9 are arranged in a plan view, and are arranged to be offset by a predetermined distance with respect to the corresponding lower holding member 8. Further, the rows of the bubble discharge ports 9 are preferably arranged at a position offset between the upper holding member 7 and the lower holding member 8 of the corresponding filter module 2 as viewed in a plan view. More specifically, the rows of the bubble discharge ports 9 are arranged in a gap between the lower holding members 8 as viewed in a plan view. Therefore, the air bubbles discharged from the bubble discharge port 9 will efficiently collide with the hollow fiber film 6 through the lower holding member 8 and rub against the hollow fiber film 6, so that it can adhere to the hollow fiber film 6 The dirty matter on the outer peripheral surface is removed.

The structure of the cleaning module 4 may be any structure that can discharge bubbles from a plurality of bubble discharge ports 9, but may be formed, for example, as shown in Figs. 1 and 3, and the filter module 2 In a one-to-one correspondence mode, a plurality of air supply ducts 10 for supplying air from an air source (not shown) are provided, and the air bubble discharge ports 9 are formed in a line in a plurality of air supply tubes 10, respectively.

Further, in the filter device, the bubble discharge port 9 of the cleaning module 4 may be offset from the lower side holding member 8 in the X direction (the left side in the drawing), and the bias direction thereof is Lower side hold The member 8 is in the same direction with respect to the offset biasing direction (the right side in the drawing) of the upper holding member 7 (that is, with respect to the lower holding member 8 on the side where the corresponding upper holding member 7 exists) The opposite side).

The lower limit of the average diameter of the bubble discharge port 9 is preferably 1 mm, more preferably 2 mm. On the other hand, the upper limit of the average diameter of the bubble discharge port 9 is preferably 10 mm, more preferably 8 mm. If the average diameter of the bubble discharge port 9 does not reach the above lower limit, there is a concern that a sufficient amount of bubble discharge cannot be obtained. On the other hand, when the average diameter of the bubble discharge port 9 exceeds the above upper limit, the amount of bubble discharge from the bubble discharge port 9 close to the supply source of the gas is large, and thus the supply amount of the bubble may become inconsistent.

The lower limit of the average diameter (average outer diameter) of the air supply pipe 10 is preferably 10 mm, more preferably 15 mm. On the other hand, the upper limit of the average diameter of the air supply pipe 10 is preferably 80 mm, more preferably 60 mm. If the average diameter of the air supply pipe 10 does not reach the above lower limit, there is a concern that a sufficient amount of air bubbles cannot be discharged. Conversely, if the average diameter of the air supply pipe 10 exceeds the above upper limit, it will be difficult to arrange the air bubble discharge port 9 of the cleaning module 4 to correspond to the gap between the adjacent filter modules 2 in each column. Care.

<discharge mechanism>

The discharge mechanism 5 includes a water collection pipe 11 for collecting the filtered liquid after the drainage nozzle 7a connected to the plurality of filter modules 2, and a suction pump for sucking the treated liquid from the water collection pipe 11. Pu 12.

<Hollow Yarn Film>

The hollow fiber membrane 6 is formed by forming a tubular shape by allowing a liquid to pass through and preventing a porous film which has passed through impurities contained in the liquid to be treated.

As the hollow fiber membrane 6, a hollow fiber membrane mainly composed of a thermoplastic resin can be used. Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinylidene fluoride, ethylene-vinyl alcohol copolymer, polyamide, polyimide, polyetherimide, polystyrene, and polyfluorene. , polyvinyl alcohol, polyphenylene ether, polyphenylene sulfide, cellulose acetate, polyacrylonitrile, polytetrafluoroethylene (PTFE), and the like. Among these materials, in particular, it is excellent in mechanical strength, chemical resistance, heat resistance, weather resistance, non-flammability, etc., and is porous polytetrafluoroethylene (PTFE), which is one-way or two-way. The expanded polytetrafluoroethylene (PTFE) is better. Further, an additive such as another polymer or a lubricant may be added to the material for forming the hollow fiber film 6 in an appropriate amount.

The average width L ₁ of the bundle upper side holding member 7 and the lower holding member 8 of the plurality of hollow fiber membranes 6 of the respective filter modules 2 in the longitudinal direction (Y direction) is larger than in the short axis direction (X The average width L _{2 in the} direction) is preferably. In other words, the existence region of the hollow fiber film 6 in the drawing direction (Z direction) and the vertical direction (XY direction) of the upper holding member 7 and the lower holding member 8 may be a rectangular shape. The hollow fiber film 6 is preferably arranged in a matrix in the longitudinal direction (Y direction) and the short side direction (X direction) of this field of existence. In addition, the "existing field" means the smallest polygonal area among the imaginary convex polygons including all the hollow fiber membranes (all polygons whose internal angles are not up to 180°).

The lower limit of the average width L ₁ of the bundle of the hollow fiber membranes 6 in the longitudinal direction is preferably 300 mm, more preferably 500 mm. On the other hand, the upper limit of the average width L ₁ of the bundle of the hollow fiber membranes 6 in the longitudinal direction is preferably 1200 mm, more preferably 1000 mm. If the average width L ₁ of the bundle of the hollow fiber membranes 6 in the longitudinal direction is not the above lower limit, sufficient filtration efficiency may not be obtained. On the other hand, if the average width L ₁ of the bundle of the hollow fiber membranes 6 in the longitudinal direction exceeds the above upper limit, the treatment of the filter module 2 may become difficult.

The lower limit of the average width L ₂ of the bundle of the hollow fiber membranes 6 in the short-axis direction is preferably 10 mm, more preferably 15 mm. On the other hand, the upper limit of the average width L ₂ of the bundle of the hollow fiber membranes 6 in the short-axis direction is preferably 100 mm, more preferably 75 mm. If the average width L ₂ of the bundle of the hollow fiber membranes 6 in the short-axis direction does not reach the above lower limit, there is a concern that sufficient filtration efficiency cannot be obtained. On the other hand, when the average width L ₂ of the bundle of the hollow fiber membranes 6 in the short-axis direction exceeds the above-described upper limit, the bubbles discharged from the cleaning module 4 to be described later cannot be reliably supplied to the hollow fiber membrane 6 . The central part of the bundle is a concern.

The lower limit of the ratio (L ₂ /L ₁ ) of the average width L ₂ of the bundle of the hollow fiber membranes 6 in the short-axis direction with respect to the average width L ₁ of the bundle of the hollow fiber membranes 6 in the longitudinal direction, It is preferably 1/80, and 1/50 is better. On the other hand, the upper limit of the ratio (L ₂ /L ₁ ) of the average width L ₂ in the short-axis direction with respect to the average width L ₁ in the long-axis direction is preferably 1/3, 1/ 10 is better. If the ratio (L ₂ /L ₁ ) of the average width L ₂ in the short-axis direction with respect to the average width L ₁ in the long-axis direction is not reached, the treatment of the filter module 2 may be changed. Difficult considerations. Conversely, if the ratio (L ₂ /L ₁ ) of the average width L ₂ in the short-axis direction with respect to the average width L ₁ in the long-axis direction exceeds the above upper limit, there may be a failure to clean the module. (4) The discharged air bubbles are surely supplied to the center portion of the bundle of the hollow fiber film 6.

The average pitch of the hollow fiber membranes 6 in the longitudinal direction is preferably larger than the average pitch in the short-side direction. The lower limit of the ratio of the average pitch in the longitudinal direction of the hollow fiber film 6 in the longitudinal direction is preferably 2/5, more preferably 1/2. On the other hand, the upper limit of the ratio of the average pitch in the longitudinal direction of the hollow fiber film 6 in the longitudinal direction is preferably 4/5, more preferably 2/3. If the ratio is not the above lower limit, the density of the hollow fiber membrane 6 in the longitudinal direction is too small, and sufficient filtration efficiency may not be obtained. On the other hand, if the ratio exceeds the above upper limit, air bubbles which are discharged from the cleaning module 4 may be sufficiently introduced into the hollow fiber film 6 from one end side in the short side direction.

The filling area of the hollow fiber membrane 6 in the above-mentioned field of existence The lower limit of the rate is preferably 20%, and 30% is better. On the other hand, the upper limit of the filling area ratio of the hollow fiber membrane 6 in the above-mentioned field of existence is preferably 60%, more preferably 55%. When the filling area ratio of the hollow fiber membrane 6 is less than the above lower limit, the number of the hollow fiber membranes 6 per unit area is too small, and sufficient filtration efficiency may not be obtained. On the other hand, when the filling area ratio of the hollow fiber membrane 6 exceeds the above upper limit, the gap between the hollow fiber membranes 6 is too small, and there is a possibility that the bubbles discharged from the cleaning module 4 are sufficiently supplied to the bundle of the hollow fiber membranes 6. The central part of the set is a concern.

In the above-mentioned field of existence, the lower limit of the number (number of rows) of the hollow fiber membranes 6 arranged in the short-side direction is preferably eight, and more preferably twelve. On the other hand, the upper limit of the number of the hollow fiber membranes 6 arranged in the short-side direction is preferably 50, and more preferably 40. If the number of the hollow fiber membranes 6 arranged in the short-side direction is less than the above lower limit, there is a concern that the filtration efficiency per unit area cannot be sufficiently ensured. On the other hand, if the number of the hollow fiber membranes 6 arranged in the short-side direction exceeds the above upper limit, bubbles which are discharged from the cleaning module 4 cannot be surely supplied to the center of the bundle of the hollow fiber membranes 6. Care.

The lower limit of the ratio of the average pitch of the average outer diameter of the hollow fiber membrane 6 in the short-side direction is preferably one. On the other hand, the upper limit of the ratio of the average pitch of the average outer diameter of the hollow fiber membrane 6 in the short-side direction is preferably 3/2, more preferably 7/5. The ratio of the average outer diameter of the hollow fiber membrane 6 to the average pitch in the short-side direction is such that the hollow fiber membrane 6 is placed in a state of being flattened in the radial direction if the lower limit is not reached. The manufacture of the filter module 2 will be Difficult to worry. On the other hand, if the ratio of the average pitch of the average outer diameter of the hollow fiber membrane 6 in the short-side direction is larger than the upper limit, the density of the hollow fiber membrane 6 in the short-side direction is too small, and thus There are concerns about not being able to achieve adequate filtration efficiency.

The lower limit of the average outer diameter of the hollow fiber membrane 6 is preferably 1 mm, more preferably 1.5 mm, and more preferably 2 mm. On the other hand, the upper limit of the average outer diameter of the hollow fiber membrane 6 is preferably 6 mm, more preferably 5 mm, and more preferably 4 mm. If the average outer diameter of the hollow fiber membrane 6 does not reach the above lower limit, the mechanical strength of the hollow fiber membrane 6 may be insufficiently insufficient. On the other hand, if the average outer diameter of the hollow fiber membrane 6 exceeds the above upper limit, the flexibility of the hollow fiber membrane 6 is insufficient, and the vibration and the oscillation of the hollow fiber membrane 6 which is generated by the contact with the bubble become insufficient. The gap between the hollow fiber membranes 6 cannot be expanded to guide the bubbles to the central portion of the bundle of the hollow fiber membranes 6, and the ratio of the surface area to the sectional area of the hollow fiber membranes 6 is too small. There are concerns about reducing filtration efficiency.

The lower limit of the average inner diameter of the hollow fiber membrane 6 is preferably 0.3 mm, more preferably 0.5 mm, and more preferably 0.9 mm. On the other hand, the upper limit of the average inner diameter of the hollow fiber membrane 6 is preferably 4 mm, more preferably 3 mm. If the average inner diameter of the hollow fiber membrane 6 does not reach the above lower limit, there is a concern that the pressure loss is excessive when the treated liquid in the hollow fiber membrane 6 is discharged. On the other hand, if the average inner diameter of the hollow fiber membrane 6 exceeds the above upper limit, the thickness of the hollow fiber membrane 6 is too small, and the mechanical strength and the effect of preventing the permeation of impurities may be insufficiently considered.

The average inner diameter of the average outer diameter of the hollow fiber membrane 6 The lower limit of the ratio is preferably 3/10, and 2/5 is better. On the other hand, the upper limit of the ratio of the average inner diameter of the average outer diameter of the hollow fiber membrane 6 is preferably 4/5, more preferably 3/5. When the ratio of the average inner diameter of the average outer diameter of the hollow fiber membrane 6 is not reached, the thickness of the hollow fiber membrane 6 is too large, which may reduce the water permeability of the hollow fiber membrane 6. On the contrary, with respect to the ratio of the average inner diameter of the average outer diameter of the hollow fiber membrane 6, if the above upper limit is exceeded, the thickness of the hollow fiber membrane 6 is too small, and the mechanical strength and the effect of preventing the permeation of impurities may be insufficiently considered. .

The lower limit of the average effective length of the hollow fiber membrane 6 along the central axis is preferably 1 m, more preferably 2 m. On the other hand, the upper limit of the average effective length of the hollow fiber membrane 6 is preferably 6 m, more preferably 5 m. If the average effective length of the hollow fiber membrane 6 does not reach the above lower limit, the oscillation of the hollow fiber membrane 6 due to bubble friction is insufficient, and the gap between the hollow yarn membranes 6 cannot be expanded to guide the bubbles to the hollow. The center of the bundle of the film 6 is a concern. On the contrary, if the average effective length of the hollow fiber membrane 6 exceeds the above upper limit, the slack of the hollow fiber membrane 6 may be excessively large due to the weight of the hollow fiber membrane 6 itself, and the filter module 2 may be caused to The installation setupability at the time of setting is deteriorating.

The lower limit of the ratio (aspect ratio) of the average effective length of the average outer diameter of the hollow fiber membrane 6 is preferably 150, more preferably 1000. On the other hand, the upper limit of the aspect ratio of the hollow fiber membrane 6 is preferably 6,000 or more. If the aspect ratio of the hollow fiber membrane 6 is not reached, the oscillation of the hollow fiber membrane 6 due to bubble friction is insufficient, and the gap between the hollow yarn membranes 6 cannot be expanded to bring the bubbles. It is guided to the center of the bundle of the hollow fiber film 6. On the other hand, if the aspect ratio of the hollow fiber membrane 6 exceeds the above upper limit, the hollow fiber membrane 6 becomes extremely slender, and therefore, when the yarn is pulled up, the mechanical strength may be lowered.

<Upper holding member>

The upper holding member 7 has a drain space 7a in which an internal space communicating with the inner cavity of the hollow fiber membrane 6 held therein is formed, and the treated water filtered by the hollow fiber membrane 6 is discharged from this internal space. .

The lower limit of the ratio of the average width L ₂ of the bundle of the hollow fiber film 6 in the short-axis direction to the average width of the upper holding member 7 when viewed from the plan view is preferably 1.05, more preferably 1.1. On the other hand, the upper limit of the ratio of the average width L ₂ of the bundle of the hollow fiber film 6 in the short-axis direction to the average width of the upper holding member 7 in plan view is preferably 1.3, and 1.2. it is good. The ratio of the average width L ₂ of the bundle of the hollow fiber film 6 in the short-axis direction to the average width of the upper holding member 7 when viewed from the plan view, if the lower limit is not reached, the strength of the upper holding member 7 There are not enough concerns. On the other hand, the ratio of the average width L ₂ of the bundle of the hollow fiber film 6 in the short-axis direction to the average width of the upper holding member 7 when viewed from the plan view, if the upper limit is exceeded, the upper holding member 7 The gap between the gaps is too small, and there is a concern that the air bubbles after the hollow fiber film 6 has been cleaned can be smoothly discharged upward, and the interval between the bundles of the curtain-shaped hollow fiber film 6 cannot be reduced. The filter device 1 has become too large a concern.

(lower holding member)

The lower holding member 8 is for holding the lower end of the hollow fiber film 6. The lower holding member 8 may be formed with the same internal space as the upper holding member 7, or the lower end of the hollow fiber film 6 may be held by a method of sealing the opening of the hollow fiber film 6. Further, the average width W of the lower holding member 8 when viewed in a plan view can be set to be the same as that of the upper holding member 7.

<framework>

The frame 3 is configured such that the plurality of filter modules 2 are arranged to be immersed in the storage by holding the upper holding member 7 and the lower holding member 8 of the plurality of filter modules 2 as described above. The state in the liquid to be treated in the filtration tank T.

The structure of the frame 3 is preferably such that it can be taken out from the filter tank T while the filter module 2 is held. Further, the frame 3 is preferably constructed such that the cleaning module 4 to be described later can be held below the filter module 2.

〔advantage〕

In the filter device 1, the lower holding member is disposed so as to be offset from the upper holding member when viewed in a plan view, so that the lower side is protected The air bubbles rising in the vertical direction around the holding member can collide with the hollow fiber film, and the cleaning efficiency of cleaning the hollow fiber film by the air bubbles is excellent. Therefore, the filter device 1 can more easily maintain the filtering ability.

[Other Embodiments]

All the points of the embodiments disclosed herein are merely illustrative and are not intended to be limited to such embodiments. The scope of the present invention is not limited to the structures of the above-described embodiments, but includes the structures disclosed in the scope of the claims and the equivalents of the scope of the claims and all modifications within the scope.

In the case of the filter device, if there are a plurality of filter modules, the arrangement pitch of the plurality of filter modules may not be a certain pitch. Further, the offset amount of the lower holding member with respect to the upper holding member and the offset amount of the bubble discharge port with respect to the lower holding member do not have to be constant, and each filter module may be different. .

Further, in the filter device, a drain nozzle may be provided in the lower holding member to discharge the treated liquid. Further, the arrangement and the number of the drain nozzles in the holding member can be arbitrarily changed.

Further, in the filter device, the cleaning module may be any one that can supply air bubbles from the lower side of the filter module, and may be, for example, a jet flow aeration device that ejects air bubbles from a diffuser or a sprayer. A bubble nozzle that mixes air bubbles in a water stream and ejects them. In addition, it can also be equipped with: the air bubbles supplied from the cleaning module can be cited A guiding mechanism that leads to the gap of the lower holding member. Moreover, a plurality of cleaning modules can be provided.

The filter device may be configured such that the outer peripheral surface side of the hollow fiber membrane is regarded as a high pressure side, and the liquid to be treated is penetrated to the inner peripheral surface side of the hollow fiber membrane, and the pressure is applied; the impregnation pressure or the inner peripheral surface side is used. The negative pressure is applied to the impregnation type in which the liquid to be treated penetrates to the inner peripheral surface side, and the inner peripheral surface side of the hollow fiber membrane is regarded as the high pressure side so that the liquid to be treated penetrates to the outer peripheral surface side of the hollow fiber membrane. Various filtering devices such as internal pressure type.

The filter module of the filter device may have a configuration in which the upper side holding member holds both ends of the hollow fiber membrane, and the lower side holding member folds the hollow fiber film into a U-shaped structure.

1‧‧‧Filter device

2‧‧‧Filter module

3‧‧‧Frame

4‧‧‧ Cleaning module

5‧‧‧Discharge agencies

6‧‧‧ hollow fiber membrane

7‧‧‧Upper holding member

7a‧‧‧Draining nozzle

8‧‧‧Bottom holding member

9‧‧‧ bubble spit

10‧‧‧Air supply pipe

11‧‧‧Water collection piping

12‧‧‧ suction pump

T‧‧‧ filter tank

Claims (8)

A filter device comprising: a plurality of hollow fiber membranes having a vertical pull-up and a plurality of filter modules for fixing the upper and lower ends of the plurality of hollow fiber membranes to the holding member; and a filter device or a plurality of cleaning modules are provided below the filter module; and the filter device of the lower side is disposed such that when viewed from a plan view, the holding member is offset from the upper side . The filter device according to claim 1, wherein the filter module has a structure in which a plurality of hollow fiber membranes are arranged in a curtain shape in a rod-shaped holding member, and a plurality of the filter modules are arranged : Parallel and equally spaced, the lower holding members of the plurality of filter modules are offset from the axial direction and the vertical direction by a predetermined distance when viewed from a plan view. The filtering device according to claim 2, wherein the offset amount of the offset bias is 30% or more and 200% or less of a pitch of the plurality of filter modules. The filter device according to claim 2 or 3, wherein the bubble discharge port of the cleaning module is disposed in a gap of the lower holding member when viewed in a plan view. The filter device according to claim 1, wherein the plurality of hollow fiber membranes disposed between the pair of holding members have a slack. The filter device of claim 2 or 3, wherein The plurality of hollow fiber membranes between the pair of holding members have slack. The filtration device according to claim 1, wherein the hollow fiber membrane is made of polytetrafluoroethylene as a main component. The filtration device according to claim 2 or 3, wherein the hollow fiber membrane is made of polytetrafluoroethylene as a main component.