KR100435162B1 - Membrane disc - Google Patents

Abstract

The present invention provides a rotating flat membrane disk capable of preventing expansion of the flat membrane.

The rotating flat membrane disk 10 of this invention is comprised by the circular flat membrane 18 adhere | attached on the bottom face of the disk 16. As shown in FIG.

The disk 16 and the flat membrane 18 are fixed to the outer periphery by the fixing portion 20 over the entire circumference, and at the same time, the plurality of partial fixing portions 22 inside the outer peripheral fixing portion 20, ( 22)... It is fixed by.

The partial fixing portions 22 are formed in a dot shape of Φ 10 mm and are disposed at intervals of 30 ° at positions Φ 500 mm and Φ 600 mm.

Description

Flat Disk Disc {MEMBRANE DISC}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to flat membrane discs, and more particularly, to flat membrane discs for use in rotating flat membrane separators for intermittent filtration operations.

The rotary flat membrane separator includes a hollow rotary shaft and a plurality of flat membrane disks mounted on the rotary shaft, and filters the water by sucking the water to be treated therein while rotating the flat membrane disk.

A flat membrane disk is a flat membrane formed on both sides of a disk-shaped support body called a disk, and this flat membrane and a disk were adhere | attached over the whole pole in the outer peripheral part.

The flat membrane disc always rotates together with the rotating shaft, thereby providing a flow velocity to the membrane surface to prevent contaminants from adhering to the membrane surface.

Therefore, the rotary flat membrane separation device can perform filtration operation at a lower power than other separation devices which purify the water to be treated and impart a flow rate to the membrane surface.

In addition, in order to maintain the permeation performance of the flat membrane, the rotary flat membrane separation device generally employs an intermittent suction method of intermittently sucking filtration of the water to be treated.

This method reduces the adhesion of the contaminated layer to the membrane surface by temporarily stopping the suction of the water to be treated, and removes and removes the contaminated layer from the membrane surface by continuously rotating the flat membrane disk.

In addition, a part of the permeated water inside the flat membrane disc flows back through the flat membrane by centrifugal force, so that the effect of some countercurrent washing is obtained.

However, the conventional rotary flat membrane separator has the disadvantage that the flat membrane is expanded from the support when the permeate flows back.

Therefore, since the flat membrane repeatedly expands each time the suction filtration is stopped, the flat membrane may be stretched to form wrinkles and the flat membrane may be damaged.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the flat disk which can prevent expansion of a flat membrane.

1 is an external view of a membrane module using the flat membrane disk of the present embodiment.

2 is a side cross-sectional view of the flat membrane disc of the present embodiment.

3 is a cross-sectional view taken along line 3-3 of FIG.

4 is an explanatory diagram for explaining a reverse flow region;

Fig. 5 is a diagram showing the transmission flow rate distribution at a distance from the center of the disc.

6 is a view showing a change over time of the filtration pressure.

FIG. 7 is a cross-sectional view of a flat disk having a shape different from that of FIG. 3. FIG.

8 is a cross-sectional view of a flat disk having a shape different from that of FIG.

(Explanation of symbols for the main parts of the drawing)

10: flat disk 14: rotating shaft

16: disc 18: flat membrane

20: outer fixing part 22: partial fixing part

In order to achieve the above object, the present invention is used in a rotating flat membrane separation apparatus, and in the flat membrane disk, wherein the flat flat membrane formed on both sides of the circular support is fixed to the support at the outer periphery of the flat membrane, the flat membrane is It is characterized by being partially fixed to both sides of the support.

According to the present invention, since the flat membrane is partially fixed to the support, expansion of the flat membrane away from the support is suppressed.

Thereby, wrinkles can be prevented from forming in the flat membrane, and breakage of the flat membrane can be prevented.

According to the present invention, since the partial fixing portion is formed in a linear or point shape and the area of the partial fixing portion is made small, the permeability of the flat membrane does not decrease.

In addition, according to the present invention, by partially arranging the fixing portion in a region where the liquid passing through the flat membrane flows back through the flat membrane, the expansion of the flat membrane can be effectively suppressed.

Next, preferred embodiments of the flat membrane disc according to the present invention will be described with reference to the accompanying drawings.

1 is an external view of the membrane module 12 using the flat membrane disk 10 of the present embodiment.

As shown in the figure, the membrane module 12 is composed of a rotating shaft 14 and a plurality of flat membrane disks 10 arranged parallel to the rotating shaft 14 at predetermined intervals, and the processing of the rotating flat membrane separating apparatus. It is immersed in raw water (treated water) stored in a tank (not shown).

The rotating shaft 14 is connected to a driving device (not shown) and is capable of rotating together with the flat membrane disk 10.

In addition, the rotating shaft 14 communicates with the inside of the flat membrane disc 10 and also communicates with a suction device (not shown) to drive the suction device, thereby generating a suction force inside the flat membrane disc 10.

FIG. 2 is a cross sectional view of the flat membrane disc 10, and FIG. 3 is a cross sectional view along the line 3-3 of FIG.

As shown in these figures, the flat membrane disk 10 is formed in a disk shape by adhering the circular flat membrane 18 to both surfaces of the circular disk 16.

The disk 16 and the flat membrane are adhered to the outer circumference over the entire circumference, and the permeate water having passed through the flat membrane 18 is prevented from leaking to the outside by the adhesive portion 20 (hereinafter, referred to as the outer circumferential fixation portion).

As a result, when a suction force is generated inside the flat membrane disc 10 (between the disc and the flat membrane), the external undiluted solution of the flat membrane disc 10 is sucked into the inside through the flat membrane 18, and the permeate is rotated by the rotating shaft 14. It is sent to

Reference numeral 24 in FIG. 2 denotes a liquid rod ring, which prevents leakage of permeate water from the rotation shaft 14 side.

In addition, as shown in Fig. 3, the flat membrane disk 10 has a plurality of partial fixing portions 22, 22,..., On the rotational axis side than the outer fixing portion 20. Is formed.

The partial fixing portions 22, 22. Is placed in a region where the permeate flows back through the flat membrane 18 (hereinafter referred to as a counter flow region) at the time of stopping the filtration operation (i.e., stopping the suction while rotating the flat membrane disk 10).

As shown in FIG. 4, this reverse flow region is generally formed outside the boundary line 34 when the flat membrane disc 10 is divided into two by a circular boundary line 34 around the rotation axis of the flat membrane disc 10. .

That is, when the flat membrane disc 10 is divided so that the area of the center part 36 and the area of the peripheral part 38 become equal, the peripheral part 38 turns into a backflow area.

For example, when the flat membrane disc 10 has a diameter of Φ 700 mm and the outer peripheral fixing portion 20 has a width of 15 mm, the backflow region is usually formed outside the boundary line 34 of Φ 500 mm.

Thus, the partial fixing portions 22 are formed in a point shape of Φ 10 mm and are disposed at intervals of 30 ° at positions Φ 500 mm and Φ 600 mm. In this way, the partial fixing portions 22, 22. Are evenly disposed in the backflow region.

Next, the operation of the flat membrane disk 10 configured as described above will be described.

The membrane module 12 applies suction to the inside of the flat membrane disc 10 and sucks and transmits the undiluted liquid from the outside of the flat membrane disc 10 through the flat membrane 18. At that time, a contaminant layer which cannot be peeled off even if the flat membrane disk 10 is rotated is gradually deposited on the membrane surface of the flat membrane 18.

Therefore, after the suction filtration is performed for a certain time, the suction is temporarily stopped to lower the suction pressure, thereby lowering the adhesion force of the contaminated layer to the flat membrane 18 and simultaneously rotating the flat membrane disc 10 to flatten the contaminated layer. Peeling removal is carried out from (18).

At that time, a part of the permeate water inside the flat membrane disc 10 flows back to the outside through the flat membrane 18.

FIG. 5 shows the permeation flow rate distribution in the flat membrane 18 of the flat membrane disk 10 of Φ 700 mm, FIG. 5A shows the filtration time, and FIG. 5B shows the filtration stop time. Here, the direction which flows inward from the exterior of the flat membrane disc 10 is made into the positive direction.

As shown in FIG. 5A, the permeation flow rate decreases as the filter moves away from the center (ie, the axis of rotation) of the flat membrane disk 10.

This is because the permeate flow rate is difficult to be obtained because centrifugal force is applied to the liquid inside the flat membrane disc 10 so that the permeate flows in the reverse direction.

However, the permeation flow rate at the time of filtration has almost no influence of centrifugal force at 50 rpm used in normal operation, and a positive permeation flow rate is always obtained even at a high speed of 200 rpm, so that no reverse flow occurs.

On the other hand, at the time of filtration timing, as shown to FIG. 5B, it turns out that permeation flow velocity is gradually reduced from the rotation shaft side to the outer side, and the direction of permeation flow velocity is reversed at the position of about 250 mm from the center.

That is, a positive permeation flow rate is always obtained on the rotational axis side from the center of 250 mm from the center, but the outer side is the counterflow region, and a flow in the opposite direction to the filtration time is formed.

Therefore, in the conventional apparatus, there is a possibility that the flat membrane 18 expands outwards every time the filtration stops in the counterflow region, and wrinkles are formed in the flat membrane 18, thereby causing the flat membrane 18 to break.

On the other hand, in the flat membrane disk 10 of the present embodiment, since the flat membrane 18 and the disk 16 are partially fixed in the reverse flow region, expansion of the flat membrane 18 can be suppressed even when the reverse flow occurs.

As a result of simulating the expansion of the flat membrane 18 with respect to the expansion prevention effect of the flat membrane 18, it was found that about 40% can be reduced.

As described above, the flat membrane disk 10 of the present embodiment partially fixes the flat membrane 18 and the disk 16 in the backflow region, thereby preventing the flat membrane 18 from expanding. Therefore, formation of wrinkles in the flat membrane 18 can be prevented, and the life of the flat membrane 18 can be improved.

In addition, in the flat membrane disk 10 of the present embodiment, since the fixing portion 22 is formed in a point shape and the area occupied by the fixing portion 22 is small, the permeability of the flat membrane 18 of the flat membrane disk 10 is Almost no degradation

Therefore, the expansion of the flat membrane 18 can be prevented without lowering the filtration capacity of the flat membrane disk 10.

In addition, according to the flat membrane disk 10 of the present embodiment, the fixing portions 22, 22... Of the flat membrane 18 and the disk 16. Since the restraint point of the flat membrane 18 is increased by forming a, the operation of increasing the rotation speed of the flat membrane disk 10 becomes possible.

For example, when operating at the rotation speed 40-60 rpm in the conventional apparatus, operation by the rotation speed 80-100 rpm becomes possible in this Example.

Therefore, a large film surface velocity can be provided to the flat membrane 18, and the formation of a contaminant layer on the flat membrane 18 can be effectively suppressed. Thereby, the frequency | count of chemical liquid washing | cleaning can be reduced.

FIG. 6 shows the aging change in the filtration pressure of the flat membrane disk 10, and repeated filtration for 27 minutes and filtration stop for 3 minutes under conditions of a set flux of 1.0 m 3 / m 2 d and SS 10 to 15 g / 1. will be.

The prior art shown by the dotted line in the figure consists of a flat film 18 and a disk 16 of the same size as the present embodiment, and is bonded only to the outer peripheral fixing portion 20.

In this embodiment, the rotation speed of the flat membrane disk 10 is data at 80 rpm, and the conventional example is data at rotation speed 60 rpm.

As shown in the figure, the filtration pressure rapidly rises after 20 days in the conventional example, and chemical liquid cleaning is required for about 30 days. This embodiment can continuously operate for about 90 days without chemical liquid cleaning.

Since the flat membrane of the conventional example has few restraint points of the flat membrane 18, the flat membrane disk 10 can only rotate at 60 rpm at low speed. Therefore, the film surface flow rate which acts on the flat membrane 18 is small, and a contaminant layer cannot be peeled off from the flat membrane 18 effectively.

In contrast, the flat membrane disk 10 of the present embodiment has the partial fixing portions 22, 22. Since the restraint point of the flat membrane 18 was increased, the flat membrane disk 10 can be rotated at a high speed of 80 rpm, and the adhesion of the flat membrane 18 to the contaminated layer can be effectively suppressed.

Thus, according to the flat membrane disk 10 of this embodiment, since it can rotate at a higher speed than the conventional example, the permeation performance of the flat membrane 18 can be improved, and the frequency of chemical liquid washing of the flat membrane 18 can be reduced. .

And in the above-mentioned embodiment, the point-shaped fixed parts 22 and 22 are formed every 30 degrees at the positions of? 500mm and? 600mm. Is formed, the shape and number of the partial fixing portions 22 are not limited thereto.

For example, in the flat disk 26 shown in FIG. 7, the fixing | fixed part 28 is formed linearly, and is arrange | positioned in the radial direction of the flat membrane disk 26,

In this case, the flat membrane 18 and the disk 16 are more firmly fixed, and the expansion of the flat membrane 18 can be reliably prevented.

In addition, in the flat membrane disc 30 shown in FIG. 8, the partial fixing part 32 is arrange | positioned along the streamline which the fluid inside the flat membrane disc 30 forms at the time of filtration stop.

That is, the partial fixing part 32 is inclined to the rear side of the rotation direction 40 as it approaches the outer peripheral part. Therefore, since the liquid inside the flat membrane disk 30 at the time of stop of filtration flows along the partial fixing part 32, the partial fixing part 32 does not become a resistance.

As a result, the partial fixing portion 32 can be prevented from interfering with the rotation of the flat membrane disk 30, and the flat membrane disk 30 can be rotated at high speed.

In addition, the shape of the partial fixing part 22 may be a dotted line shape, for example, by arrange | positioning as shown in FIG. 7 or FIG. 8, the flat membrane 18 and the disk (do not enlarge the area which the fixing part 22 occupies). 16) can be more firmly fixed.

In addition, although the partial fixing part 22 was arrange | positioned in the backflow area | region in the above-mentioned embodiment, it is not limited to this.

In the above-described embodiment, the flat membrane 18 is directly attached to the disk 16, but may be attached via a nonwoven fabric or the like.

In addition, the disk 16 may be made of a water-permeable member so that liquid can pass through the disk 16.

As described above, according to the flat disk according to the present invention, the flat membrane is partially fixed to the support, and the flat membrane is prevented from expanding away from the support, thereby preventing the formation of wrinkles in the flat membrane, thereby preventing damage to the flat membrane. can do.

Claims (7)

In a flat membrane disk, which is used in a rotating flat membrane separator, wherein a circular flat membrane formed on both sides of a circular support is fixed to the support at the outer periphery of the flat membrane. And the flat membrane is partially fixed to both surfaces of the support. 2. The flat disc according to claim 1, wherein the partial fixing portion between the flat membrane and the support member is linear or pointed. 3. The flat disc according to claim 1 or 2, wherein the partial fixing portion is formed in an area in which liquid passed through the flat membrane inside the flat disc is flowed back through the flat membrane. The flat membrane disc according to claim 1 or 2, wherein the partial fixation portion is disposed in the peripheral portion when the flat membrane is divided into two areas of the circular center portion and the peripheral portion of the central portion. The flat membrane disc according to any one of claims 1 to 2, wherein the partial fixing portion is formed along a streamline in which the liquid inside the flat membrane disc is formed by the rotation of the flat membrane disc. . In a flat membrane disk, which is used in a rotating flat membrane separator, wherein a circular flat membrane formed on both sides of a circular support is fixed to the support at the outer periphery of the flat membrane. At the position on the side of the rotation axis than the outer periphery of the flat membrane, the flat membrane disk is located along the streamline formed by the rotation of the flat membrane disc in a region where the liquid passed through the flat membrane inside the flat membrane disc flows back through the flat membrane. A flat film disc, which is partially fixed to a support. In a flat membrane disk, which is used in a rotating flat membrane separator, wherein a circular flat membrane formed on both sides of a circular support is fixed to the support at the outer periphery of the flat membrane. At the position on the side of the rotation axis rather than the outer periphery of the flat membrane, when the flat membrane is divided into two areas of the circular central portion and the periphery of the central portion, the periphery portion of the flat membrane is formed along the streamline formed by the rotation of the flat membrane disk. A flat disk characterized in that partly fixed to the support.