JPH08281078A - Floating hollow-fiber membrane module - Google Patents

Abstract

PURPOSE: To obtain a hollow-fiber membrane module with the sludge between the membranes of the module easily discharged. CONSTITUTION: Both ends of a hollow-fiber membrane 1 are supported at the two upper and lower parts or at one part. The filtered and cleaned water is collected from the supporting part in this hollow-fiber membrane module. The module consists of a water collecting part 2 formed at the lower supporting part of the membrane and a float 5 connected to the upper part 3 of the membrane 1 or to the membrane. A means for supplying or discharging air into or from the float is furnished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane module, and more particularly to a floating type which is suitable for immersing a hollow fiber membrane module in water for filtration and is suitable for use in a large treatment tank. The present invention relates to a hollow fiber membrane module.

[0002]

2. Description of the Related Art Recently, many filters using hollow fiber membranes have been used for filtering water and the like. Further, it is used for filtering industrial water by bundling thousands to tens of thousands of hollow fiber membranes in a bundle and fixing the ends with an adhesive. A bundle of thousands to tens of thousands of hollow fiber membranes is called a hollow fiber membrane module. Is this hollow fiber membrane module disposable?
Alternatively, when a certain amount or more of dirt adheres, cleaning with clean water or chemical water or flushing treatment is usually performed. Further, as disclosed in JP-A-5-220355, a hollow fiber membrane module can be used for a long time by heating a liquid containing fine particles and a sludge substance and then filtering with a hollow fiber membrane module. It is suggested to do so. Further, when such a hollow fiber membrane module is used in a large-capacity treatment tank, the hollow fiber membrane tension is kept constant by a housing and other supports.

[0003]

However, according to the above-mentioned conventional configuration, when performing cleaning or flushing treatment with clean water or chemical liquid water, it is necessary to prepare clean water or chemical liquid water and to use it. It is necessary to treat the chemical liquid water, which requires man-hours and costs. Further, when a heated liquid is used, it is necessary to carry out special equipment and treatment, which requires man-hours and cost as in the above case. In addition, when a large-capacity treatment tank that keeps the tension of the hollow fiber membranes constant is large, a large number of hollow fiber membranes are arranged close to each other and the tension is kept constant. It is difficult to discharge the sludge substance adhering to the membrane surface from the space between the hollow fiber membranes by filtration without expanding the space between the membranes. Furthermore, when the hollow fiber membrane module is immersed in water and used, the tension of the hollow fiber membrane is kept constant, so it is not possible to respond to changes in the water level. Exposed. Therefore, there is a problem that it cannot be used by immersing it in environmental water where the water level cannot be artificially controlled.

Focusing on the above-mentioned conventional problems, the present invention is a floating type hollow that can adhere to the membrane surface of a hollow fiber membrane bundle and easily discharge foreign matter between the membranes to prevent deterioration of filtration performance. An object is to provide a thread film module. Further, even in a large-sized treatment tank in which the hollow fiber membrane module is immersed in water, sludge substances between the hollow fiber membranes can be discharged in response to changes in the tension and looseness of the hollow fiber membrane, and the hollow fiber membrane was immersed and used. In this case, it is an object of the present invention to provide a floating hollow fiber membrane module that can follow fluctuations in water level.

[0005]

In order to achieve the above-mentioned object, a floating hollow fiber membrane module of the present invention comprises a hollow fiber membrane bundle formed by bundling hollow fiber membranes, and a filtered water collecting portion at the lower end of the bundle. And a float is connected to the support portion at the upper end. Further, an air supply / exhaust means for supplying / exhausting air to / from the float can be connected to enable adjustment of the tension of the hollow fiber membrane bundle by adjusting the buoyancy of the float.

[0006]

According to the above construction, the water collecting portion is provided in the lower supporting portion of the hollow fiber membrane bundle, and the floating portion connected to the upper supporting portion of the hollow fiber membrane or the hollow fiber membrane is provided. By changing the module length, it is possible to follow the fluctuation of the water level, so the hollow fiber membrane module is not exposed to the air,
Moreover, since the tension of the hollow fiber membranes changes and the hollow fiber membrane spacing increases, the sludge interposed between the membranes can be easily discharged. Further, even if the water level does not change, the hollow fiber membrane can be tensioned and loosened alternately by moving the float up and down, and sludge can be discharged at intervals between the hollow fiber membranes.

[0007]

EXAMPLES Hereinafter, specific examples of the floating hollow fiber membrane module according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows the first embodiment of the floating hollow fiber membrane module of the present invention.
The whole block diagram of an Example is shown. In FIG. 1, the hollow fiber membrane 1
Has one end fixed to the water collecting part 2 and the other end fixed to the support 3. The support body 3 is connected to the float 5 via the connection body 4. The water collecting section 2 is provided with a water collecting pipe 6 for collecting purified water. Further, the water collecting section 2 may be provided with an air diffusing section for air scrubbing cleaning. The connecting body 4 is formed in a string shape, a chain or a bar shape. In the above structure, the water collecting portion 2, the support body 3, and the connection body 4
Is submerged in water, and the float 5 has a buoyancy force for floating the support 3 and the connecting body 4.

Next, the operation of the above structure will be described. When the floating type hollow fiber membrane module is immersed in water for use, the float 5 moves up and down along with the fluctuation of the water level. As shown in FIG. 1, when the water level is high, the hollow fiber membranes 1 are stretched by the floats 5, the space (S) between the hollow fiber membranes is narrowed, and the hollow fiber membranes are separated from each other by water flow or air scrubbing. Easily rub against each other to remove sludge attached to the membrane surface. As shown in FIG. 2, when the water level is low, the floats 5 are lowered, the hollow fiber membranes 1 are in a slackened state, the intervals between the hollow fiber membranes are widened, and the hollow fiber membranes are trapped between the peeled hollow fiber membranes. Sludge is easily discharged. Also,
When the float 5 moves up and down, the hollow fiber membrane 1 is stretched or loosened to promote breathing, thereby promoting sludge discharge.

When the floating type hollow fiber membrane module of the present invention is used by being immersed in environmental water and used as an intake port of a fresh water facility, pretreatment is carried out at the time of intake of water, and the hollow fiber is caused by natural fluctuation of water level. The sludge trapped between the membranes is discharged. In particular, when it is used as an intake of a seawater desalination facility, the water level changes twice a day due to the ebb and flow of the tide, so sludge is regularly discharged without inputting energy. When immersed in a raw water tank, sludge is discharged by changing the water level in the raw water tank by an existing raw water pump without giving a mechanical action to the hollow fiber membrane module.

Next, FIG. 3 shows the overall construction of the second embodiment of the floating hollow fiber membrane module of the present invention. Hollow fiber membrane 1
Is folded back and both ends are fixed to the water collecting part 2. A plurality of or a single support 11 is arranged at the folded position of the hollow fiber membrane 1, and one or a plurality of support bodies 11 are collectively supported by the support 11 through the hollow fiber membrane 1. The support 11 has a ring shape, a plate shape, or a comb shape. Multiple or single support 1
1 is connected to the connecting body 4, and the connecting body 4 is a float 5
It is connected to.

In the above structure, the operation will be described next. Since the respective connecting members 4 are connected to the float 5, the degree of freedom when the float 5 moves up and down due to the fluctuation of the water level increases, and the hollow fiber The membrane 1 is often stretched and loosened to increase sludge discharge. The operation is similar to that of the first embodiment, and thus detailed description will be omitted.

Next, FIG. 4 shows an overall configuration diagram of a third embodiment of the floating hollow fiber membrane module of the present invention. In FIG. 4, a flexible tube 13 is connected to the float 12, and the tube 13 is connected to an air pump 15 via a solenoid valve 14.
It is connected to the. The float 12 is made of a stretchable material, and changes its buoyancy by changing the amount of air from the air pump 15. For example, the solenoid valve 14 is constituted by a two-position three-port, the first port is connected to the air pump 15, the second port is connected to the float 12, and the third port is connected to the atmosphere. Further, the air from the air pump 15 is discharged to the float 12 at one position (A), and the air from the float 12 is discharged to the atmosphere at the other position (B).

Next, the operation of the above structure will be described. The air pump 15 sends air to the float 12 via the solenoid valve 14 and the tube 13. The float 12 receives air and swells, and the buoyancy of the float 12 increases. Along with this, the float 12 rises, the support 3 is pulled up via the connecting body 4, and the hollow fiber membrane 1 is in a tensioned state. Next, the solenoid valve 14 is switched from one position (A) to another one position (B). As a result, the air in the float 12 is released into the atmosphere via the solenoid valve 14, and the float 12 contracts. Therefore, the float 1
The buoyancy of 2 becomes small. Along with this, the float 12 sinks, and the support 3 also sinks via the connecting body 4, and the hollow fiber membrane 1
Becomes loose. As described above, even when the air pump 15 and the solenoid valve 14 are used in a place where the water level does not fluctuate.
By operating, the membrane spacing of the hollow fiber membranes 1 is changed, and the sludge trapped between the hollow fiber membranes can be easily discharged.

In FIG. 5, the membrane is fixed by the housing,
The conventional hollow fiber membrane module in which the membrane tension was kept constant and the module of the present invention were used for river water at flux = 0.
The change with time of the operating pressure when a constant flow rate operation of 5 [m / d] is performed is shown. As shown in the figure, in the conventional module, the filtration pressure exceeded 140 [kpa] in about 5 months and became unusable, whereas in the present invention, the increase in the filtration pressure was moderate and the filtration pressure was about 1 year. It can be used and has twice the membrane life of conventional modules.

[0015]

As described above, according to the present invention,
By providing a float connected to the hollow fiber membrane, the module length of the hollow fiber membrane changes due to the vertical movement of the water level, or the floating of the float itself, so that the hollow fiber membrane is not exposed and the tension and slack of the hollow fiber membrane are reduced. Sludge can be easily discharged by changing and expanding or reducing the space between hollow fiber membranes. Therefore, the number of steps for cleaning the hollow fiber membrane module can be reduced, and the cost can be reduced because the simple configuration and natural force can be used. Further, there is an effect that the usage period of the hollow fiber membrane module is extended.

[Brief description of drawings]

FIG. 1 shows an overall configuration diagram of a first embodiment of a floating hollow fiber membrane module of the present invention.

FIG. 2 is a diagram for explaining the operation of the first embodiment of the floating hollow fiber membrane module of the present invention.

FIG. 3 shows an overall configuration diagram of a second embodiment of the floating hollow fiber membrane module of the present invention.

FIG. 4 shows an overall configuration diagram of a third embodiment of the floating hollow fiber membrane module of the present invention.

FIG. 5 is a characteristic comparison diagram of filtration pressures of a conventional example module and an example module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane, 2 Water collecting part 3,11 Support body, 4 Connection body, 5,12 Float, 13 Tube 14 Solenoid valve 15 Air pump,

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Okuno 1-14-1 Kanda, Chiyoda-ku, Tokyo Inside Hirit Plant Construction Co., Ltd.

Claims (2)

[Claims] 1. A floating-type hollow fiber membrane, characterized in that a bundle of hollow fiber membranes formed by bundling hollow fiber membranes is provided with a collecting portion for filtered water, and a float is connected to a supporting portion at the upper end. module. 2. The floating type according to claim 1, wherein an air supply / exhaust means for supplying / exhausting air to / from the float is connected so that the tension of the hollow fiber membrane bundle can be adjusted by adjusting the buoyancy of the float. Hollow fiber membrane module.