JP3293663B2 - Hollow fiber membrane module - Google Patents

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 which is mainly used directly attached to a raw water supply tap having a relatively high water pressure such as tap water and is incorporated in a water purifier to which high pressure is applied during water purification. About.

[0002]

2. Description of the Related Art In recent years, a filter using a filtration membrane having micropores such as a hollow fiber membrane can remove fine dust and various germs in raw water. It is being widely used for purification of water and the like.

[0003] In such a filter, the hollow fiber membrane is bundled in a U-shape, and the bundled end is fixed by a potting material such as a polyurethane resin so as not to block the open end of the hollow fiber membrane. The hollow part of the thread membrane is confidentially partitioned from the outer surface and fixed to the cylindrical case body.

[0004]

As described above, the potting material layer has a role of partitioning the hollow portion of the hollow fiber membrane from the outer surface in a secret manner and fixing the hollow portion to the cylindrical case body. Water pressure is constantly applied because it is used directly attached to the tap, and instantaneous high pressure is applied due to sudden opening and closing of the raw water supply tap, and in summer, etc., it is used as a potting material by increasing the water temperature The thermoplastic resin is easily softened, and the potting layer and the tubular case main body are separated from each other due to the synergistic action with the above-mentioned water pressure, so that the performance as a water purifier may not be maintained.

[0005] As a solution to such a problem, an uneven portion or a tapered portion which is expected to have an anchor effect is provided on the inner wall surface of the potting portion of the cylindrical case main body, or the potting material is increased in resin amount to increase the potting layer. Attempts have been made to prevent the potting layer from peeling off by increasing the thickness of the potting layer.

However, when the uneven portion is provided inside the cylindrical case body, a mold for manufacturing the cylindrical case body by injection molding becomes complicated, the mold cost becomes expensive, and the molding cycle becomes long. , Resulting in high costs.

In the case where the tapered portion is provided inside the cylindrical case main body, the mold is simple and the cost is not increased, and a certain effect is obtained. It has not yet been possible to completely prevent peeling of the potting layer, which occurs when a momentary high pressure is applied.

[0008] When the potting layer is made thicker, the strength of the potting layer itself is increased and an effect of preventing peeling is produced. However, not only is a large amount of resin required, the cost is increased, but also the hollow fiber membrane used is reduced. Effective membrane area is reduced,
The performance as a water purifier is reduced, such as a decrease in filtration flow rate.

The present invention solves such a problem, and a hollow fiber membrane module capable of using an effective membrane area more effectively without causing peeling even when the water temperature rises instantaneously in a high pressure state or in summer or the like. The purpose is to provide.

[0010]

According to the present invention, there is provided an all-filtration type hollow tube in which a porous hollow fiber membrane bundle whose ends are bundled and fixed with a potting material while the open ends are kept open is bundled inside a cylindrical case. In the thread membrane module, the inside of the cylindrical case is attached to the inner wall of the case of the convergence fixing portion by the potting material.
A tapered portion tapering toward the opening end of the hollow fiber membrane is provided, and the tapered portion is on an extension of the tapered portion,
In addition, a groove-shaped cut portion having the deepest portion in the direction of the discharge hole of the purified water is provided over the entire circumference, and the following (1)
And a hollow fiber membrane module having a shape defined by the range of the expression (2). 3 ≦ h (1) 5 ≦ θ ≦ 20 ° (2) (where h is the distance between the inner wall surface of the cylindrical case of the potting material and the outermost peripheral portion of the porous hollow fiber membrane ( mm) and θ
Indicates the angle of the tapered portion. ).

The hollow fiber membrane module of the present invention is used alone or in combination with an adsorbent such as activated carbon and connected to a raw water supply plug such as a tap.

As the hollow fiber membrane, those of various materials such as polyolefin, polysulfone and cellulose which are generally used as a water purifier can be used. Above all, it is a polyolefin-based porous hollow fiber membrane which has been hydrophilized, and the fibrils formed by multiple layers from one surface to the other surface and the space between the fibrils formed by the nodes fixing both ends of the fibrils are mutually If a membrane that penetrates from one side to the other side of the membrane, for example, polyethylene hollow fiber / EHF (registered trademark of Mitsubishi Rayon Co., Ltd.) is used, the ability to remove various germs in tap water is also improved. Large and preferred.

[0013] Further, as a potting material used for the potting portion, polyurethane, which is usually used,
Resins such as unsaturated polyester and epoxy are used as they are.

In the method of fixing the hollow fiber membrane module and the cylindrical case main body with a potting material as in the hollow fiber membrane module of the present invention, if the distance between the cylindrical case main body and the outermost peripheral portion of the hollow fiber membrane is small. The smaller the distance, the more easily the potting material for fixing between the distances does not spread, and thus the more the peeling is likely to occur.

Even if the potting material has a sufficient thickness to be fixed between the cylindrical case body and the outermost peripheral portion of the hollow fiber membrane, the potting material becomes convex in the discharge direction of purified water due to surface tension. It becomes a letter shape. The radius of curvature of the U-shape becomes larger and sharper as the outermost peripheral portion distance between the cylindrical case body and the hollow fiber membrane is smaller. At the bottom of this radius of curvature, cracks tend to occur due to stress concentration due to pressure such as water pressure, and the generated cracks grow to cause peeling.

In the present invention, the distance h (mm) between the inner wall surface of the cylindrical case of the potting portion and the outermost peripheral portion of the hollow fiber membrane is defined as:
By setting 3 ≦ h, stress concentration is reduced, and cracks are hardly generated. Here, if h is less than 3 mm, stress concentration is remarkable and cracks are easily generated. This distance h is 3
If it is not less than mm, the stress concentration is eased and sufficient, but if it is too large, the resin is unnecessarily required and the cost is increased.
A thickness of about 10 mm is sufficient and preferable in terms of stress relaxation and cost.

Further, since the hollow fiber membrane module of the present invention is used by directly attaching to the raw water supply tap, the potting layer always has a pressure at the time of water supply, a pressure generated at the time of raw water filtration, or an abrupt change of the raw water supply tap. Momentary high pressure due to opening and closing etc. is applied, and these pressures exert a shearing force on the interface between the potting layer and the cylindrical case main body, which may cause displacement and peeling, and the performance as a water purifier Cannot be maintained.

In the hollow fiber membrane module of the present invention, the groove-like cut portion having the deepest portion in the discharge direction of the purified water prevents a displacement between the cylindrical case body and the potting layer by a so-called anchor effect. In addition, the tapered portion where the extension line is within the cut portion is relaxed by applying a horizontal force to the tapered portion of the cylindrical case body by the taper portion angle θ, and the shear force itself is also cut on the tapered extension line. Due to the role of the part, displacement and peeling due to shearing force are less likely to occur.

The angle θ of the tapered portion is such that the distance h between the inner wall surface of the cylindrical case and the outermost peripheral portion of the hollow fiber membrane and the extension of the tapered portion are within the cut portion, and the angle is 5 ≦ θ ≦ 20 °. is necessary.

If the angle θ is less than 5 °, the shearing force is not sufficiently relaxed by the component force, and the shearing force tends to cause displacement and peeling. If the angle θ exceeds 20 °, the relaxation by the component force of the shearing force is sufficient, but the condition that the extension line of the tapered portion is within the cut portion is deviated from the condition that the tapered portion is not sufficiently long, and the effect of the relaxation is insufficient. Is lost.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an example of a water purifier accommodating the hollow fiber membrane module of the present invention, and FIG.
FIG. 2 shows a partially enlarged cross-sectional view of a groove-shaped cut portion and a tapered portion in FIG. 1.

Referring to FIG. 1, the structure of the hollow fiber membrane module of the present invention will be outlined. The hollow fiber membrane module housed in the outer container 8 of the water purifier converges the hollow fiber membrane 1 in a U-shape.
By fixing the converging end with a potting layer 2 made of polyurethane resin or the like so as not to close the open end of the hollow fiber membrane, the hollow part of the hollow fiber membrane 1 is kept secret from the outer surface and the cylindrical case body 3 It is fixed. A groove-like cut portion 4 and a tapered portion 5 are provided in a portion corresponding to the potting layer 2 on the inner surface of the cylindrical case body 3. The groove-shaped cut portion 4 has the deepest portion in the direction of the purified water discharge hole 7 of the hollow fiber membrane module. The arrow is
The flow direction of water at the time of water purification is shown.

Although FIG. 1 shows a hollow fiber membrane module having a filtration section composed of the hollow fiber membrane 1 and the activated carbon 7, a module having only the hollow fiber membrane 1 may be used.

(Examples 1 to 3 and Comparative Examples 1 to 3) The hollow fiber membrane module was completely submerged in hot water having a water temperature of 40 ° C. in a state of being mounted on a main body container used as a water purifier. Further, a fatigue test was conducted in which a load and a no-load state of 7.5 kg / cm ² of hydrodynamic pressure were each set to a cycle of 10 seconds.

In this fatigue test, the life is defined as the life until a gap and a separation occur between the cylindrical case main body and the potting layer and water is broken, and the number of cycles is evaluated. As shown in Table 1, the distance h between the inner wall surface of the cylindrical case of the potting portion and the outer peripheral portion of the porous hollow fiber membrane and the angle θ of the tapered portion were variously changed, and a fatigue test was performed. Shown.

[0027]

[Table 1]

[0028]

According to the hollow fiber membrane module of the present invention, by setting the distance between the inner wall surface of the cylindrical case and the outermost peripheral portion of the hollow fiber membrane to a specific range, the distance between the cylindrical case body and the outermost peripheral portion of the hollow fiber membrane can be improved. Stress concentration occurring in the potting layer is reduced, and cracks are less likely to occur. Further, the groove-shaped cut portion having the deepest portion in the discharge direction of the purified water prevents a displacement between the cylindrical case body and the potting layer by a so-called anchor effect.

The tapered portion having an extension line in the cut portion is first relaxed by applying a shear force to the tapered portion of the cylindrical case body in the horizontal direction by the taper portion angle θ, and the shear force itself is also tapered. Even when the cut portion on the extension line bears, it is difficult to cause displacement and peeling due to shearing force.

[0030] Due to these effects, the occurrence of peeling due to an instantaneous high pressure state or a rise in water temperature in summer or the like is extremely reduced, and the durability of the hollow fiber membrane module is greatly improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a water purifier accommodating a hollow fiber membrane module of the present invention.

FIG. 2 is a partially enlarged sectional view of a groove-shaped cut portion and a tapered portion in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane 2 Potting layer 3 Cylindrical case main body 4 Groove-shaped cut part 5 Taper part 6 Purified water discharge hole 7 Activated carbon 8 Outer container

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kenji Honjo 4-160 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi Japan Mitsubishi Rayon Co., Ltd. (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B01D 63/02 B01D 63/00 500 C02F 1/44

Claims (1)

(57) [Claims] An all-filtration type hollow fiber membrane module in which a porous hollow fiber membrane bundle whose ends are fixed and fixed with a potting material while the open end is kept open is bundled inside a cylindrical case. From the inside of the cylindrical case toward the open end of the hollow fiber membrane,
The tapered portion is provided on the extension of the tapered portion, and a groove-shaped cut portion having the deepest portion in the discharge hole direction of the purified water is provided over the entire circumference. And a hollow fiber membrane module having a shape defined by the following formulas (1) and (2). 3 ≦ h (1) 5 ≦ θ ≦ 20 ° (2) (where h is the distance between the inner wall surface of the cylindrical case of the potting material and the outermost peripheral portion of the porous hollow fiber membrane ( mm) and θ
Indicates the angle of the tapered portion. )