JPH04367714A - Sheet of porous hollow-fiber membrane - Google Patents

Abstract

PURPOSE:To provide a sheet of porous hollow-fiber membrane for a porous hollow-fiber membrane module which has a good reverse-flow washing effect and is easy in handling to form the module. CONSTITUTION:A sheet of porous hollow-fiber membrane is formed by a method in which the both end parts of the hollow-fiber membrane 1, folded at a specified length without being cut at its ends, are bound with a fibrous material 2 crossing at nearly right angles to the porous hollow-fiber membrane 1 to form a chain stitch structure. Simultaneously, since the porous hollow-fiber membrane 1 is bound with water soluble threads 3 crossing with the porous hollow-fiber membrane 1 between the both end parts of the porous hollow-fiber membrane 1 at intervals of 30cm or less to form a chain stitch structure, a module can be formed with easy handling, and the water soluble threads 3 are already dissolved at the time of reverse-flow washing to loose easily the porous hollow-fiber membrane 1 to improve the reverse-flow washing effect.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous hollow fiber membrane sheet for large-sized filters used for industrial wastewater filtration.

0002

[Prior Art] Porous hollow fiber membranes are used as filtration materials in many fields, including medical fields such as blood purification and artificial lungs, purification of drinking water such as tap water, and filtration and purification of industrial wastewater. It is being As the scope of its use has expanded and the amount of use has increased, various improvements have been made to obtain homogeneous and superior filtration materials from simple filtration materials, and among them, porous hollow fiber membranes have been developed without changing the form. A special sheet forming technique was developed to obtain a homogeneous sheet (Japanese Patent Application Laid-Open No. 1986-5).
(Refer to Publication No. 7965), the uniform arrangement of porous hollow fiber membranes formed at the end of the module during module formation, and improved operability during module manufacturing have been achieved, making it possible to mass-produce more homogeneous modules. Furthermore, it is now possible to provide excellent modules such as improved filtration accuracy due to improved dispersibility of porous hollow fiber membranes. Modules for industrial use with a quality hollow fiber membrane portion of 1 m in length and several thousand converged fibers are now being manufactured and used.

0003

[Problems to be Solved by the Invention] By the way, in a porous hollow fiber membrane module having such a sheet-like form,
In cases where there is little clogging and the amount of porous hollow fiber membrane used is small, such as in the case of tap water filtration, there is no problem with using a disposable method, but as in the case of industrial applications, porous hollow fiber membranes If the amount of membrane used is large and the amount of membrane clogging is large, replacing the porous hollow fiber membrane module each time is problematic both in terms of cost and work. For example, at present, porous hollow fiber membranes are backwashed by air injection treatment in water to eliminate clogging, and then used repeatedly.

[0004] When backwashing is performed when the amount of porous hollow fiber membranes used is large and the number of converged membranes is large, such as in the case of industrial applications, it is necessary to clean the porous hollow fiber membranes as freely as possible while dispersing them as much as possible during backwashing. The more you can move around, the more effective it will be to clear the clogged state.

[0005] From this point of view, the above-mentioned Japanese Patent Application Laid-Open No. 62-5
It is considered effective to use the porous hollow fiber membrane sheet disclosed in Japanese Patent No. 7965. This sheet-like material has porous hollow fiber membranes arranged at regular intervals. By arranging the porous hollow fiber membranes in the converging end (fixed part) and the intermediate part in a non-crowded manner, air bubbles are more likely to act on the membrane surface during backwashing, reducing the backwashing effect. growing.

However, porous hollow fiber membrane modules generally used for industrial purposes often have an effective membrane length of 1 m or more, and have a width of 1 m or more by the method disclosed in the above-mentioned publication. When manufacturing a porous hollow fiber membrane module, it is extremely difficult to handle a sheet-like material in which only the edges at both ends are restrained and the middle part is not restrained; It is considered an essential requirement. According to the method disclosed in the above-mentioned publication, it is possible to fix the porous hollow fiber membrane at a predetermined interval in the middle part of the sheet material during potting during module formation, and by this fixing, the middle part Since the parts are restrained at predetermined intervals, handling becomes easy, but on the other hand, the porous hollow fiber membrane becomes difficult to disintegrate during backwashing, reducing the cleaning effect.

[0007] Accordingly, an object of the present invention is to provide a porous hollow fiber membrane sheet for a porous hollow fiber membrane module that has a large backwashing effect and is easy to handle during module formation.

[0008]

[Means and operations for solving the problems] In order to achieve the above-mentioned object, the gist of the present invention is to provide a porous hollow fiber membrane that is folded back to a predetermined length without being cut at the end, and a porous hollow fiber membrane that is In a porous hollow fiber membrane sheet-like article, the porous hollow fiber membranes are connected in the vicinity of both ends thereof in a chain-knit structure, and the porous hollow fiber membranes are arranged in a direction substantially perpendicular to the porous hollow fiber membranes. Between the two ends of the membrane sheet, water-soluble threads intersect with the porous hollow fiber membrane and are arranged in a chain stitch pattern at intervals of 30 cm or less to fasten the porous hollow fiber membrane. A porous hollow fiber membrane sheet-like material characterized by:

Hereinafter, the present invention will be explained in detail along with its operation based on the drawings. FIG. 1 is a plan view showing an example of a porous hollow fiber membrane sheet of the present invention, in which 1 is a porous hollow fiber membrane, 2 is a fibrous material, 3 is a water-soluble thread, 4, 4 ' is the ear (
(ends) are shown respectively.

As shown in FIG. 1, the porous hollow fiber membrane 1 of the present invention is continuously folded in a zigzag pattern at the edges 4, 4' of a sheet-like material without cutting the porous hollow fiber membrane 1. Both ear portions 4 are formed by being folded back in a continuous manner.
4', the porous hollow fiber membrane 1 is fastened and fixed in a chain-knit pattern by the fibrous materials 2, 2 arranged near the folded portion. Furthermore, a water-soluble thread 3 is arranged between the ears 4 and 4', and the water-soluble thread 3 forms a porous hollow fiber membrane located between both ears 4 and 4'. 1 is the ear part 4, 4
'It is tightened and fixed in a chain-knit pattern.

The porous hollow fiber membrane 1 used in the present invention may be made of any commercially available material such as polypropylene or polyethylene polysulfone.

The fibrous materials 2, 2 disposed on the ears 4, 4' are usually bulky crimped yarns made of thermoplastic synthetic fiber multifilament, but if necessary, the fibrous materials 2, 2 disposed on the ears 4, 4'
It is also possible to use a water-soluble thread 3 as the fibrous material 2 for one or both of the parts.

The folded width of the porous hollow fiber membrane 1 can be arbitrarily set within a range that does not damage the porous hollow fiber membrane 1 at the folded portion.

Any commercially available yarn can be used as the water-soluble yarn 3 disposed between the ears 4, 4', and any fiber such as monofilament or multifilament can be used. There is no problem with the form.

[0015] By fixing the porous hollow fiber membrane 1 in a chain-knit pattern in this way, the porous hollow fiber membrane 1 can be fixed without being damaged, making it easy to form a sheet with a rough structure, and at the same time making it easy to handle. Work efficiency also improves.

[0016] Furthermore, the spacing between the water-soluble threads 3 is 3.
It needs to be less than 0 cm; if it exceeds 30 cm, the bundled porous hollow fiber membranes 1 tend to come apart, making it difficult to handle them during module formation work and the like. Furthermore, the intervals between the water-soluble threads 3 do not necessarily have to be equal.

[0017] In the present invention, the water-soluble thread 3 disposed between the ear parts 4, 4' is for temporarily restraining the porous hollow fiber membrane 1 in the middle part, and is for temporarily restraining the porous hollow fiber membrane 1 in the middle part. The yarn 3 may be arranged roughly or diagonally.

Next, a method for producing the porous hollow fiber membrane sheet of the present invention will be described. As the porous hollow fiber membrane 1 used in the present invention, any material commercially available such as polypropylene and polyethylene polysulfone can be used as described above.

[0019] Such a porous hollow fiber membrane 1 has a large number of micropores formed on the membrane surface, so it has low strength and is brittle, so it is impossible to form a sheet using a normal knitting machine or a loom. Generally, it is used converging in a comb shape, but in the present invention, it is used in Japanese Patent Application Laid-Open No. 1-266258
No. 91673) By using a special knitting machine as shown in the publication, the porous hollow fiber membrane 1 can be folded back at the ears 4, 4' without damaging the porous hollow fiber membrane 1. . In this case, the porous hollow fiber membrane 1
The folding of the porous hollow fiber membrane 1 at the ears 4, 4' is done relatively gently to avoid damage. It is valid.

In the present invention, in order to fasten the porous hollow fiber membrane 1 in a chain-knit pattern using the water-soluble threads 3 arranged between the ears 4, 4', it is necessary to fasten the ears 4, 4'. This is possible by using a similar mechanism. The fixation of the porous hollow fiber membrane 1 by the water-soluble threads 3 is temporary in order to facilitate the workability until the module is formed.
Even looser fixation is sufficient. In addition, the interval between the water-soluble threads 3 used is not particularly limited, but the interval is 3
When it is 0 cm or more, the porous hollow fiber membrane 1 becomes easily disassembled and easily damaged, making it difficult to handle and reducing workability.

[0021] The porous hollow fiber membrane sheet formed by fixing at least the middle part with the water-soluble threads 3 is collected in the required amount and fixed at one or both ends with a potting resin, It is used as a module in a filter device for industrial water and industrial wastewater.

FIG. 2 shows a module manufactured using the porous hollow fiber membrane sheet of the present invention and set in a water passage system. In the figure, 5 indicates a potting section; 6 is a raw water introduction valve, 7 is an air introduction valve,
8 is a drainage valve, 9 is a filtered water valve, and 10 is an air release valve.

In the illustrated filter device, each valve 7, 8, 9, 10 other than the raw water introduction valve 6 is closed, and the raw water introduction valve 6 is opened to create a state in which the housing is filled with raw water to be filtered. If maintained for several minutes, the water-soluble thread 3 will easily dissolve in water. Thereafter, when the raw water introduction valve 6, the air introduction valve 7, the filtrate water valve 9, and the air release valve 10 are closed and the drainage valve 8 is opened, the dissolved fiber components are discharged together with the raw water. Next, normal filtration is performed by opening the raw water introduction valve 6 and the filtrate water valve 9 while keeping the air introduction valve 7, drainage valve 8, and air vent valve 10 closed. If filtrate accumulates on the membrane surface and the differential pressure increases, close the raw water introduction valve 6, drainage valve 8, and filtrate water valve 9, and then close the air introduction valve 7 and air release valve 10. When opened, air is introduced into the housing and backwashing begins.

At this time, since the water-soluble threads 3 no longer exist, each fiber constituting the porous hollow fiber membrane module is in a disjointed state, and can be easily moved by air bubbles, resulting in an extremely effective backwashing effect. The value will be high.

[0025]

EXAMPLES The present invention will be specifically explained below based on examples. Porous hollow fiber membrane: 16 EHF270T (polyethylene hollow fiber membrane manufactured by Mitsubishi Rayon Co., Ltd.) used in both ears
; Polyester fiber 150d/36f crimped yarn Sheet forming width (knitting width); 1400 mm Sheet forming; Sheet forming was performed using the apparatus shown in JP-A No. 1-266258 (Japanese Patent Application No. 63-91673) . Middle part: A total of 6 pieces of Solblon SS type 100d/30f (water-soluble fiber manufactured by Nippon Vinylon Co., Ltd.) are arranged at 20 cm intervals, and the porous hollow fiber membrane bundle is tightened in a chain-knitted manner and such a sheet-like material is wound. It is installed in the housing as a sushi shape, and both ears are potted with resin using a centrifugal method, and the effective length is 13.
A module with a diameter of 60 mm and a membrane area of 12 m2 was manufactured.

Test results: The effect of the water-soluble yarn placed in the middle part during module formation was remarkable, and the sheet-like product could be made into a sushi roll shape very easily and was easy to handle. Further, when the above module was set in a water flow system and water at room temperature was set, the water-soluble threads dissolved in 1 to 2 minutes, and the backwashing effect due to the air jetting into the water was also significant.

[0027]

Effects of the Invention As is clear from the above explanation, the porous hollow fiber membrane sheet of the present invention has porous hollow fiber membranes formed in a sheet shape, so that it is possible to form porous hollow fibers with uniform porous hollow fibers during module formation. This makes it possible to arrange the thread membrane, and the cleaning effect becomes extremely large, especially when backwashing is performed when a large module for industrial use becomes clogged and the module is used repeatedly. In addition, since the middle part of the porous hollow fiber membrane sheet is partially fixed, it is easy to handle when incorporating the module into a filter device, and is suitable for industries that require long porous hollow fiber membrane sheets. It also becomes possible to use the module for other purposes without any problems. Furthermore, during backwashing when clogged, water dissolves and removes the water-soluble fibers that have already been partially fixed in the middle, so the porous hollow fiber membranes become more loose and the backwashing is smoother. It has remarkable effects when applied to industrial modules, such as effective cleaning.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of a porous hollow fiber membrane sheet of the present invention.

FIG. 2 is a longitudinal sectional view showing an example of a module manufactured using the porous hollow fiber membrane sheet of the present invention used as an industrial filter.

[Explanation of symbols]

1 Porous hollow fiber membrane 2
Fibrous material 3 Water-soluble threads 4, 4' Ear portion 5 Potting portion 6
Raw water introduction valve 7 Air introduction valve 8 Drainage valve

Claims (1)

[Claims] Claim 1: A porous hollow fiber membrane that is folded back to a predetermined length without being cut at the end, and a porous hollow fiber membrane that is fastened in the vicinity of both ends of the porous hollow fiber membrane with a chain-knit structure; In a porous hollow fiber membrane sheet comprising a fibrous material arranged in a direction substantially perpendicular to the membrane, water-soluble threads are arranged between the two ends of the porous hollow fiber membrane sheet. 1. A porous hollow fiber membrane sheet, characterized in that the porous hollow fiber membranes are intersected with each other and fastened in a chain-knit manner at intervals of 30 cm or less.