JPH08112517A - Hollow fiber membrane module - Google Patents

Abstract

PURPOSE: To prevent the rupture of hollow fiber membranes and to improve and stabilize the quality thereof by providing the neck part of the hollow fiber membranes with a sealing material with buffer materials for suppressing the oscillation of the hollow fiber membranes, thereby dispersing concentrated bending stresses. CONSTITUTION: The neck part of a bundle 4 of the hollow fiber membranes sealed by the top end 6 and bottom end 8 of a case 2 is provided with layers 42, 44 of the buffer materials for suppressing the oscillation of the hollow fiber membranes 5. The layers 42, 44 of the buffer materials are formed by stacking many granular materials on each other. Small-diameter beads made of synthetic resins, such as PP and PE, having adequate thickness and the sp.gr. lighter than the sp.gr. of a permeated liquid are used for the upper layer 42 and small- diameter beads made of glass, ceramics, etc., having the sp.gr. heavier than the sp.gr. of the permeated liquid are used for the lower layer 44. The failure at the neck part by bending fatigue is thereby prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a large number of hollow fiber membranes as filtration membranes and is widely used in water purifiers and other industrial applications such as medical and oil / water separation. Regarding modules.

[0002]

2. Description of the Related Art An example of a conventional hollow fiber membrane module of this type is shown in FIG.

The illustrated example shows a so-called cross-flow type hollow fiber membrane module. That is, the cylindrical case 102 is arranged vertically, and the bundle 104 of hollow fiber membranes is arranged.
Is loaded in the case 102 in the vertical direction, and is sealed by the upper end portion 106 and the lower end portion 108 of the case 102.

The upper end 106 and the lower end 10 of the case 102
8 includes a case upper lid 110 and a case lower lid 112, respectively.
Spaces 124 and 126 are provided outside the upper end 106 and the lower end 108 of the sealed case 102, in which the ends of the hollow fiber membranes are open.
In addition, by incorporating the O-rings 114 and 116 in the fitting portion of the case upper lid 110 and the case lower lid 112, the liquid to be treated does not leak to the outside from the spaces 124 and 126 at the upper and lower ends of the case 102. There is.

The case upper lid 110 and the case lower lid 112 are provided with liquid passage ports 118 and 120, respectively. Further, two permeate outlets 122, 122 are provided on the side surface of the case 102.

An upper end portion 106 and a lower end portion 10 of the case 102
As shown in FIG. 4, the sealed state of No. 8 includes a gap between the inner surface of the case 102 and the bundle 104 of hollow fiber membranes, and a gap between the individual hollow fiber membranes 105 with a certain thickness. A liquid held inside and sealed with a sealing material (potting agent) 128, and the liquid inside the case 102 (permeated liquid in this conventional example).
Is outside the upper and lower ends of the case 102, that is, the spaces 124, 12
I try not to leak to 6.

However, only the outside of the hollow fiber membrane 105 is blocked, and the internal passage of each hollow fiber membrane 105 communicates with the outer spaces 124 and 126.

Further, the fixing state of the sealing material 128 is shown in FIG.
There are various types, such as a flat type as shown in FIG. 4A, and a convex and concave shape attached to the outside of the hollow fiber membrane 105 as shown in FIG. 4B. However, the sealing material 128 is firmly fixed to the thin hollow fiber membrane 105.

In the conventional example of FIG. 3, during filtration, the liquid to be treated enters through the lower liquid passage port 120 while being pressurized, passes through the space 126, and each hollow fiber membrane 105.
Of the upper liquid passage port 118 through the space 124.

While the liquid to be treated passes through the passages inside the hollow fiber membranes 105, the liquid to be treated is placed outside the hollow fiber membranes 105 due to the pressure difference between the inside and outside of the hollow fiber membranes 105. Part of the permeates while being filtered. The permeate is the case 102.
Flows out through the two permeate outlets 122, 122 on the side surface of the sheet (FIG. 3 (a)).

Further, when the filtration membrane surface is clogged and the filtration capacity is lowered, backwashing is performed. During this backwashing, the operation of pressing the liquid to be treated is stopped and the permeate is pressurized, and
The pressure difference between the inside and outside of 05 is reversed. Then, FIG. 3 (b)
As shown in FIG.
2, 122 to enter the case 102, permeate the hollow fiber membrane 105 from outside to inside, and the upper and lower liquid passage ports 118,
It flows out from 120. At this time, particles, dust, oil droplets, etc. that adhere to the inner surface of the hollow fiber membrane 105 and cause clogging, this time, due to the pressure of the permeated liquid from the opposite outside,
It easily separates from the inner surface of the hollow fiber membrane 105 and flows to eliminate clogging.

[0012]

However, in the case of the above-mentioned prior art, the hollow fiber membrane vibrates laterally when the filtration device is operating. In particular, when the liquid permeates from the outer side to the inner side of the hollow fiber membrane, the rolling of the hollow fiber membrane becomes large. In the conventional example of FIG. 3, it is the case of back washing in (b). Then, as a result of the lateral oscillation, in the case of the conventional hollow fiber membrane module, the boundary surface 130 of the sealing material to which the root of the hollow fiber membrane 105 that is sealed is fixed.
There is a problem that the hollow fiber membrane 105 is broken at the location (FIG. 4), and the required liquid to be treated cannot be filtered and separated.

Therefore, it is necessary to carefully set the conditions of the backwashing operation (flow rate of the permeate during backwashing, backwashing operation time) so that the hollow fiber membrane is not broken.

When the liquid permeates from the outer side to the inner side of the hollow fiber membrane, the horizontal sway of the hollow fiber membrane becomes large because the entrance of the permeated liquid on the side surface of the case is close to one side. It is considered that the liquid flowing from the inlet of the permeated liquid hits the side of the hollow fiber membrane in a directional manner.

Further, as a result of the hollow fiber membrane 105 swaying in the lateral direction, the boundary surface 13 of the sealing material at the root is sealed.
The reason for fracture at 0 can be explained as follows.

The sealed root of the hollow fiber membrane 105 is
It is firmly fixed by the sealing material 128. From the boundary surface 130 of the encapsulant, it is suddenly released from the fixation of the encapsulant 128. Therefore, the hollow fiber membrane 105 will be shaken in a large manner in the same manner as the free center of the hollow fiber membrane 105. And Therefore, repetitive bending stress concentrates at the root. If this bending stress exceeds the fatigue limit of the hollow fiber membrane, fatigue failure will occur. Since the hollow fiber membrane is a thread-shaped tube with an outer diameter of about 1 mm or thinner, it bends flexibly, and even if there is lateral vibration in the part that is not held, bending stress caused by it Is small. However, since the bending stress concentrates on the boundary surface that is firmly fixed by the sealing material 128, the bending stress becomes large, leading to fatigue failure.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to improve the method of holding the hollow fiber membrane at the sealed root. Disperses the bending stress that tends to concentrate,
The purpose is to prevent breakage of the hollow fiber membrane and improve and stabilize the quality.

[0018]

In order to achieve the above object, according to the present invention, a bundle of hollow fiber membranes is loaded in a case, and the space between the case and the hollow fiber membranes is placed at the open end of the case. In the hollow fiber membrane module in which the gap between the hollow fiber membranes and the gaps between the hollow fiber membranes are sealed with a sealing material, a cushioning material for suppressing the swinging of the hollow fiber membrane is provided at the base of the hollow fiber membrane with the sealing material. It is characterized by being provided.

The cushioning material is characterized by being composed of a large number of particles.

When the case is arranged vertically and the hollow fiber membrane is sealed at the upper end of the case, a large number of granules having a lower specific gravity than the liquid in the case are filled in the case as a cushioning material. Is characterized by.

Further, when the case is arranged vertically and the hollow fiber membrane is sealed at the lower end of the case, a large number of granules having a heavier specific gravity than the liquid in the case are filled in the case as buffer materials. It is characterized by having done.

[0022]

In the present invention, since the layer of the cushioning material that suppresses the swing of the hollow fiber membrane is present at the root part where the hollow fiber membrane is sealed, the hollow fiber membrane is provided between the layers. Is suppressed in the lateral direction, and the bending stress that tends to concentrate at one point on the boundary surface of the sealing material is dispersed. The bending stress generated thereby in the layer of the cushioning material and at the boundary surface thereof is significantly smaller than the bending stress when concentrated at one point on the boundary surface of the sealing material.

When the layer of the cushioning material is composed of a large number of particles, since the large number of particles are stacked, the large number of particles are movable, but the inertial force of the particles or The frictional force between the granules or between the granules and the hollow fiber membrane acts as a resistance to suppress the lateral sway of the hollow fiber membrane.

Further, when the case is arranged in the vertical direction and the hollow fiber membrane is sealed at the upper end or the lower end of the case, the liquid in the case (the liquid to be treated) becomes a large number of particles serving as a cushioning material. Liquid permeates inside the hollow fiber membrane and permeates to the outside of the hollow fiber membrane; conversely, when the liquid to be treated is outside the hollow fiber membrane and permeates toward the inside of the hollow fiber membrane) Therefore, if particles with a low specific gravity (small diameter beads) or particles with a high specific gravity (small diameter beads) are put in the case, the particles with a low specific gravity float up due to buoyancy, and the particles with a high specific gravity It sinks due to the weight and stacks on the roots of the sealed hollow fiber membranes at the upper and lower ends of the case to automatically form a layer of cushioning material.

When the hollow fiber membrane is sealed at the upper and lower ends of the case, both particles having a low specific gravity and particles having a high specific gravity may be filled in the case.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

A hollow fiber membrane module according to an embodiment of the present invention will be described with reference to FIG.

Similar to the conventional example shown in FIG.
It is a cross flow type. A cylindrical case 2 is arranged in the vertical direction, a bundle 4 of hollow fiber membranes is loaded in the case 2 in the vertical direction, and is sealed by an upper end portion 6 and a lower end portion 8 of the case 2. .

A hollow fiber membrane is, as shown in FIG.
The book is a thin thread-shaped tube, and the tubular membrane wall part becomes a filtration membrane, and the fluid such as liquid is permeated from the outside to the inside or from the inside to the outside due to the pressure difference. The impurities are removed and necessary components are concentrated. Since the filtration area of one hollow fiber membrane is small, and therefore the filtration capacity is small, a predetermined filtration capacity is obtained by collecting a large number of them.

A case upper lid 10 and a case lower lid 12 are fitted and covered on the upper end portion 6 and the lower end portion 8 of the case 2, respectively, and outside the upper end portion 6 and the lower end portion 8 of the sealed case 2. A space 24 in which the end of each hollow fiber membrane is open,
26 is provided.

The O-rings 14 and 16 are attached to the case upper lid 1
By incorporating it into the fitting portion of the case 0 and the case lower lid 12, the liquid to be treated does not leak outside from the spaces 24 and 26 at the upper and lower ends of the case 2. The case upper lid 10 and the case lower lid 12 are provided with liquid passage ports 18 and 20, respectively. Two permeate outlets 22, 22 are provided on the side surface of the case 2.

The sealing state at the upper end portion 6 and the lower end portion 8 of the case 2 is the same as that shown in FIG. 4, and the gap between the inner surface of the case 2 and the bundle 4 of hollow fiber membranes is one. One hollow fiber membrane 5
The gap between them is filled with a sealing material (potting agent) 28 with a certain thickness and solidified, and the liquid inside the case 2 (permeated liquid in this embodiment) is the upper and lower ends of the case 2. It is designed so that it does not leak to the outside of the parts, that is, the spaces 24 and 26.
However, only the outside of the hollow fiber membrane 5 is blocked,
The inner space (hollow passage) of the hollow fiber membrane 5 is an external space 24, 2.
It is in communication with 6.

The fixing state of the sealing material 28 is shown in FIG.
There are various types, such as a flat type as shown in FIG. 4A, and a convex and concave shape attached to the outside of the hollow fiber membrane 5 as shown in FIG. 4B. However, the sealing material 28 is firmly fixed to the thin hollow fiber membrane 5.

In the present invention, further, as shown in FIG. 1, the hollow fiber membrane 5 is shaken at the base portion of the bundle 4 of hollow fiber membranes sealed by the upper end portion 6 and the lower end portion 8 of the case 2. Layers of dampening cushions 42, 44 were provided. This cushioning layer 42, 4
4 has a moderate layer thickness.

In this embodiment, the layers 42,44 of cushioning material are used.
Was constructed by stacking a number of granules. Further, a large number of particles serving as a cushioning material are provided in the upper cushioning material layer 4
A liquid having a specific gravity smaller than that of the liquid outside the hollow fiber membrane, that is, the permeated liquid in this embodiment, for example, a small diameter bead made of synthetic resin PP (polypropylene) or PE (polyethylene) was used as 2. For the lower buffer layer 44, a bead having a smaller specific gravity than the liquid outside the hollow fiber membrane, that is, the permeate, such as glass or ceramic, having a small diameter is used.

These granules are located on the side surface of the case 2.
Case 2 from the permeated liquid outlets 22, 22 in fixed amounts
The particles with a low specific gravity are lifted by the buoyancy, and the particles with a high specific gravity sink due to their own weight to the root of the sealed hollow fiber membranes 5 at the upper and lower ends of the case 2. When stacked, the layers 42, 44 of cushioning material will be automatically configured. If it is concerned that these particles may flow out through the permeate outlets 22, 22, a mesh filter may be installed at the outlets 22, 24 to prevent these particles from flowing out.

The hollow fiber membrane module of the embodiment constructed as described above operates as follows.

In FIG. 1, during the filtration process, the liquid to be treated enters from the lower liquid passage port 20 while being pressurized and rises in the passage inside the hollow fiber membrane 5 one by one through the space 26. Then, through the space 24, it exits from the upper liquid passage port 18.
While the liquid to be treated passes through the passages inside the hollow fiber membranes 5 one by one, the pressure difference between the inside and outside of the hollow fiber membranes 5 causes a difference in the hollow fiber membranes 5.
Part of the liquid to be treated permeates to the outside of the while being filtered. The permeated liquid flows to the outside through the two permeated liquid outlets 22, 22 on the side surface of the case 2.

Further, when the filtration membrane surface is clogged and the filtration capacity is lowered, the pressurizing operation on the side of the liquid to be treated is stopped and the permeate is pressurized to reversely wash the hollow fiber. The pressure difference inside and outside the membrane 5 is reversed. Then, the liquid flows backward, the permeated liquid enters the case 2 through the outlets 22 and 22, permeates the hollow fiber membrane 5 from the outside to the outside, and flows out from the upper and lower liquid passage ports 18 and 20. Go.

During the filtration process, particles, dust, oil droplets, etc., which have adhered to the inner surface of the hollow fiber membrane 5 due to pressure from the inside and have caused clogging, are now the opposite pressure of the permeated liquid from the outside. Thus, the hollow fiber membrane 5 is easily separated from the inner surface and flows, thereby eliminating clogging.

During this backwashing operation, the permeate flowing in from the outlets 22, 22 collides with the hollow fiber membrane 5 in a directional manner, so that the hollow fiber membrane 5 and the bundle 4 of hollow fiber membranes are laterally aligned. It shakes greatly.

In that case, in the present invention, the cushioning material layers 42 and 44 for suppressing the shaking of the hollow fiber membrane 5 are present at the sealed root portion of the hollow fiber membrane 5, and Layer 4
Since the particles 2 and 44 are formed by stacking a large number of particles, the large number of particles are movable, but the inertial force of the particles and the force between the particles or between the particles and the hollow fiber membrane are large. The frictional force acts as a resistance to suppress the lateral fluctuation of the hollow fiber membrane 5.

As a result, lateral swaying of the hollow fiber membrane 5 is suppressed between the thicknesses of the layers, from 0 at the tightly bound interface of the sealing material 28 to the upper surface of the cushioning material layer. Since even a large shake at the boundary is continuously and gently connected, the bending stress that tends to concentrate at one point on the boundary surface of the sealing material 28 is dispersed. Layer 4 of cushioning material generated thereby
The bending stress in the inside of 2, 44 and at the boundary surface thereof is
Compared with the bending stress when concentrating on one point of the boundary surface of 8,
It will be much smaller. Therefore, bending fatigue fracture at the sealed root portion of the hollow fiber membrane 5 is prevented.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment.

In this embodiment, the liquid to be treated flows inside the hollow fiber membrane and permeates to the outside. On the contrary, the liquid to be treated is filtered from the outside to the inside of the hollow fiber membrane. It may be transparent while being transmitted. In that case, a large lateral shake of the hollow fiber membrane occurs during normal filtration operation. A large number of particles forming the buffer layer may be selected based on the specific gravity of the liquid outside the hollow fiber membrane, that is, the liquid to be treated, and lighter or heavier than that.

The embodiment was a cross-flow type hollow fiber membrane module in which a bundle of hollow fiber membranes was linearly loaded and sealed at both ends of the case, but in the present invention, the bundle of hollow fiber membranes is U-shaped. It is naturally applicable to a type in which the bundle of hollow fiber membranes is bent and sealed only at one end of the case.

The layer of the cushioning material, which is formed at the sealed root of the bundle of hollow fiber membranes, for suppressing the fluctuation of the hollow fiber membranes,
It is not limited to stacking a large number of particles. For example, a hollow fiber membrane is formed by forming a layer of a material having appropriate elasticity without being attacked by a liquid to be treated or a permeated liquid, that is, a rubber material having appropriate hardness, a synthetic resin having appropriate flexibility, or the like. It may be a structure for elastically holding the sealed root.

[0048]

As described above, in the present invention, since the layer of the cushioning material for suppressing the swing of the hollow fiber membrane is provided at the sealed root portion of the hollow fiber membrane, Lateral swaying of the hollow fiber membrane is suppressed between thicknesses, and bending stress that tends to concentrate at one point on the boundary surface of the sealing material is dispersed. Bending fatigue failure at is prevented.

When the case is arranged vertically and the hollow fiber membrane is sealed at the upper end portion or the lower end portion of the case, a layer of cushioning material for suppressing the swing of the hollow fiber membrane is formed by a large number of particles. If the particles are configured and the particles that are lighter and heavier are selected based on the specific gravity of the liquid in the case and filled in the case, the buffer material layer is automatically configured. It is very easy and inexpensive.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cross-flow type hollow fiber membrane module in which a case is vertically arranged according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a hollow fiber membrane.

FIG. 3 is a vertical cross-sectional view of a cross-flow type hollow fiber membrane module in which a case is arranged in a vertical direction in a conventional example, (a) shows a state during processing, and (b) shows a state during backwashing. Show.

FIG. 4 is an enlarged view of an end portion in which the hollow fiber membrane module is sealed.

[Explanation of symbols]

 2 case 4 bundle of hollow fiber membranes 5 hollow fiber membrane 6 upper end 8 lower end 10 case upper lid 12 lower lid 14, 16 O-ring 18, 20 passage opening 22 passage opening 24, 26 space 28 sealing material (potting agent) 42 , 44 layers of cushioning material

Claims (4)

[Claims] 1. A bundle of hollow fiber membranes is loaded into a case, and a gap between the case and the hollow fiber membranes and a gap between the hollow fiber membranes are sealed with a sealing material at the opening end of the case. In the hollow fiber membrane module, a buffer material that suppresses swinging of the hollow fiber membrane is provided at the base of the hollow fiber membrane with respect to the sealing material. 2. The hollow fiber membrane module according to claim 1, wherein the cushioning material is composed of a large number of particles. 3. When the case is arranged vertically and the hollow fiber membrane is sealed at the upper end of the case, a large number of particles having a specific gravity smaller than that of the liquid in the case are filled in the case as a cushioning material. The hollow fiber membrane module according to claim 2, wherein 4. When the case is arranged vertically and the hollow fiber membrane is sealed at the lower end of the case, a large number of granules having a higher specific gravity than the liquid in the case are filled in the case as a cushioning material. The hollow fiber membrane module according to claim 2, wherein