JP2000202252A - Flat membrane filter and filtering method of liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat membrane filter capable of sucking liquid and solid- liquid separating even if the flat membrane is in half-dipped state, that is, is not completely dipped into water, and a novel filtering method using the flat membrane. SOLUTION: In the flat membrane 10 for solid-liquid separating by attaching the filter membranes to cover hollow parts 1a, 1b formed in a frame body 1, having suction ports 4a, 4b communicated with the hollow parts 1a, 1b and dipping in the liquid to suck the liquid from suction ports 4a, 4b, the communicating ports 6a, 6b of the hollow parts 1a, 1b with the auction ports 4a, 4b are provided only in the bottom of the frame body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat membrane filter for performing solid-liquid separation of a liquid containing solid matter such as sewage or various wastewaters, and a filtration method using the flat membrane filter. Attach a filtration membrane as covering the formed hollow part and have a suction port communicating with the hollow part,
The present invention relates to an improvement of a flat membrane filter that performs solid-liquid separation by being immersed in a liquid and sucking the liquid from a suction port, and a method of filtering a liquid using the flat membrane filter.

[0002]

2. Description of the Related Art Conventionally, a filtration membrane is provided so as to cover a hollow portion of a frame body, and a suction port communicating with the hollow portion is provided. As a flat membrane filter for performing membrane separation, that is, solid-liquid separation of solids contained therein, for example, in activated sludge drainage treatment, immersion in a liquid to separate sludge while sucking and removing treated water by immersion in a treatment tank. There is a type of flat membrane filter. (JP-B 4-70958, JP-A-4-265128, etc.).

[0003] In such a submerged flat membrane filter, the suction port is generally communicated with the upper portion of the hollow portion of the frame covered with the filtration membrane, assuming that the flat membrane filter is submerged in the liquid. It is provided with an opening at the frame head (Japanese Patent Laid-Open No. 7-2427).
No. 1, JP-A-7-194947, JP-A-9-38471, JP-A-9-57070, JP-A-9-122457, JP-A-10-66847, etc.). Therefore, in the solid-liquid separation using such a flat membrane filter, it is necessary to completely sink and immerse the membrane surface of the filter in the liquid. This is because the suction port communicating with the hollow part of the frame, that is, the filtration chamber, is provided at the head of the frame, and communicates with the upper end of the hollow part (filtration chamber). This is because air is sucked from the filtration membrane surface, the negative pressure in the hollow part (the filtration chamber) is broken, and the liquid cannot be sucked.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is intended to suck liquid even when the flat membrane filter is in a semi-submerged state, that is, even when it is not completely submerged in water. To provide a flat membrane filter capable of solid-liquid separation,
Another object of the present invention is to provide a novel filtration method using the flat membrane filter.

[0005]

Means for Solving the Problems To achieve the above objects,
The flat membrane filter of the present invention has a suction port connected to the hollow portion while attaching the filtration membrane so as to cover the hollow portion formed in the frame, and is immersed in the liquid to suck the liquid from the suction port. In the flat membrane filter which performs solid-liquid separation by performing the above, a communication port between the hollow portion and the suction port is provided only at a bottom portion of the frame. This enables solid-liquid separation even when the flat membrane filter is in a semi-submerged state. Further, an air vent is provided at the head of the frame, so that the suction in the half-submerged state can be further smoothly performed.

Further, the filtration method of the present invention is a filtration method in which a liquid to be treated is separated into a solid and a liquid by a flat membrane filter immersed therein, and a filtration tank for the liquid to be treated is provided. The flat membrane filter is immersed in a semi-submerged state, a liquid is sucked to perform solid-liquid separation, and the clogging of the flat membrane filter can be determined based on a rise in the water level of the filtration tank. . Accordingly, clogging of the flat membrane filter can be determined by a simple method, the flat membrane filter can be used effectively, and the replacement cycle can be lengthened.

Other characteristic means will be described in the description of the embodiments of the present invention.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing preferred embodiments of the present invention. FIG.
FIGS. 2A, 2B, and 2C are schematic plan views of an embodiment of the flat membrane filter of the present invention.
1 is an arrow view (top view), BB sectional view, and CC sectional arrow view. FIG. 3 is a DD sectional view of FIG. FIG.
FIG. 4 is a partially enlarged perspective view illustrating a method of forming a liquid flow path.

In FIGS. 1 to 3, reference numeral 1 denotes a frame-like frame made of hard plastic, which has two independent hollow portions 1a and 1b. The hollow portions 1a and 1b are formed in a window shape penetrating the frame 1, and the filtration membranes 2a and 2b are formed in the hollow portions 1a and 1b.
1b is spread on the frame 1 so as to cover both sides. The filtration membranes 2a and 2b are generally composed of a thin plastic film having fine pores and a porous nonwoven fabric supporting the thin plastic film. Recently, a structure in which a porous plastic film is reinforced with a cloth has been proposed. In the present invention, any of these filtration membranes can be employed, and as a method of spreading on the frame, adhesion by an adhesive, heat welding, or any other spreading method can be used. In addition, these filtration membranes are no more than 0.1.
Although it is about 5 mm thick, it is enlarged in each figure.

In the hollow portions 1a and 1b, which are filtration chambers, felt-like porous support members (mats) made of carbon fiber that support the filtration membranes 2a and 2b on both surfaces and form a flow path of the filtrate. 3) 3a and 3b fill the hollow portions 1a and 1b and are mounted so as to be in contact with the wall surface of the frame (FIG. 3).

Reference numerals 4a and 4b denote suction pipes attached to the head of the frame 1, which are suction ports according to the present invention. Reference numeral 5 denotes a liquid flow path formed on the peripheral edge of the frame 1. The liquid flow path 5 is connected to the suction ports 4 a, 4 b, and extends vertically along the peripheral edge of the frame 1. It comprises a horizontal flow path (header flow path) 5c connected to the vertical flow paths 5a, 5b and the communication ports 6a, 6b opening to the hollow portion 1b. Reference numerals 7a and 7b denote connection flow paths that connect the hollow part (filtration chamber) 1a and the hollow part (filtration chamber) 1b. Reference numerals 8a and 8b denote air vents, which communicate with the hollow portion (filtration chamber) 1a and open at the head of the frame 1.

In the present embodiment, in order to facilitate processing, holes forming the liquid flow paths 5a, 5b, 5c are formed as shown in FIG.
As shown in FIG. 1, the frame 1 is formed of a stepped groove X formed in a side end surface of the frame 1 and a lid Y that covers the stepped groove X densely. The term “closely covering” refers to a state in which the groove and the lid are completely sealed with, for example, an adhesive or another seal, and no liquid or air leaks. Further, from the viewpoint of ease of machining, as shown in the figure, the stepped groove X may be formed so as to penetrate to the end of the frame body, and the groove end face may be sealed with a plug Z. By forming each hole in this manner, processing of a long hole becomes easy and the cost can be reduced.

Next, the operation of the flat membrane filter of the present invention and the filtration method of the present invention will be described. FIG. 5 is a partially broken perspective view illustrating the filtration method of the present invention. In the figure,
Numeral 10 denotes a flat membrane filter of the embodiment shown in FIGS. Reference numeral 11 denotes a suction header connected to the suction pipes 4a and 4b (not shown), and a suction pump (not shown).
Connected to the suction port. 12 is a filtration tank for the water to be treated in which the flat membrane filter 10 is immersed, 13 is a supply pipe for the water to be treated, and 14 is a non-contact water level gauge, which is installed in accordance with the upper end of the flat membrane filter 10. .

[0014] Initially, and dispensing water to be treated from the feed pipe 13, filtered suction amount water to be treated supply amount is set so as to balance upon suction filtration with water level H _0. Here, in the flat membrane filter of the present invention, since the communication ports 6a and 6b communicating with the suction pipes 4a and 4b are opened only at the bottom of the frame 1, the flat membrane filter 10 is not completely immersed as shown in FIG. Even in the half-submerged state, liquid can be sucked without sucking air. In this structure, suction filtration is possible as long as the communication ports 6a and 6b are immersed. When the air vents 8a and 8b are provided, the hollow portion (filtration chamber) that is not immersed is always kept at the atmospheric pressure, and a gas-liquid boundary is easily formed between the air and the lower liquid sucked by the negative pressure. Air is not mixed.

The initial water level H₀Supply of treated water
The amount and the suction amount (discharge amount) are balanced, but the suction pressure
Is constant, the suction filtration volume is reduced due to clogging of the filtration membrane.
descend. As emissions decrease, water levels rise and
The immersion area of the membrane filter, that is, the filtration area increases. This filter
Supply of processing liquid due to increase in suction filtration volume due to increase in excess area
Solid-liquid separation is performed at a water level balanced with the amount. like this
Then, the filtration process is performed while the water level rises sequentially.
Level H at which the water level rises and the entire surface of the filtration membrane is immersed _fReach
Then the water level gauge 14 will operate, emit a signal, and replace the filter.
Or signal the need for cleaning.

As described above, in the flat membrane filter of the present invention, filtration and solid-liquid separation can be performed even when the filter is in a semi-submerged state. In addition, if the flat membrane filter of the present invention is immersed in the filter tank in a semi-submerged state to perform solid-liquid separation, clogging of the filter membrane can be detected due to an increase in the water level of the filter tank, which is very convenient.

In the flat membrane filter according to the above-described embodiment, a filter-membrane supporting member is mounted in a window-like hollow portion (filtration chamber) penetrating the frame. This structure is simple and good filtration performance is obtained, but the hollow part is not a penetrated form, but simply forms a concave part, forms a filtration channel inside if necessary, and attaches a support member It is preferable that the filtration membrane surface is provided on both sides to make the filter compact, and in some cases, the present invention can be applied to a filter having a filtration surface on only one side.

Also, the case where two hollow portions are formed in the frame has been described, but it is also possible to provide two or more hollow portions, and in some cases even if only one hollow portion is provided. Good. A plurality of suction ports can also be appropriately opened in the frame if necessary. The communication port that opens at the bottom of the frame may also be open at the lower part of the hollow part, and the number and arrangement thereof can be appropriately selected. Further, regarding the liquid flow path connecting the communication port and the suction port, an appropriate form can be selected according to the shape of the filter frame, and in some cases,
It is also possible to connect a tube to a communication port that opens at the lower part of the hollow portion and directly suction the tube. In this case, the tube serves as a liquid flow path, and the opening of the tube serves as a suction port.

Regarding the support member provided in the hollow portion, this support member is for preventing the deformation of the filtration membrane and for securing the filtration flow path. Conventionally, the support member is made of felt, wire mesh, plastic perforated plate or nonwoven fabric. And the conventional support members can be used in the filter of the present invention.

However, the support member, which is a felt-like mat made of carbon fibers, used in the above-described embodiment exhibits novel characteristics that are not present in conventional support members in terms of liquid permeability, shape retention, and the like. It is particularly suitable for use in a submerged-type flat membrane filter and has a small decrease in filtration performance. In this case, in order to prevent the filtration membrane surface from being deformed into a concave shape due to suction, it is preferable that the thickness of the support member is slightly increased so as to be flat during suction.

[0021]

According to the flat membrane filter of the present invention, a filtration membrane is attached so as to cover a hollow portion formed in a frame, and a suction port communicating with the hollow portion is provided. In a flat membrane filter that performs solid-liquid separation by sucking a liquid from the suction port, a communication port between the hollow portion and the suction port is provided only at the bottom of the frame body. Liquid separation can be performed, and the filter can be easily installed. Further, in the case where an air vent communicating with the hollow portion is provided at the head of the frame, more stable solid-liquid separation can be performed.

According to the filtration method of the present invention, in the filtration method in which the liquid to be treated is solid-liquid separated by a flat membrane filter immersed therein, a filtration tank for the liquid to be treated is provided, and the filtration tank of the present invention is provided in the filtration tank. Since the flat membrane filter is immersed in a semi-submerged state, solid-liquid separation is performed by sucking the liquid, and the clogging of the flat membrane filter can be determined by the rise in the water level of the filtration tank.
The solid-liquid separation process can be easily managed.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of an embodiment of the flat membrane filter of the present invention.

2 (a) is a view taken along the line AA of FIG. 1 (top view), FIG. 2 (b) is a sectional view taken along the line BB of FIG. 1, and FIG. 2 (c).
The figure is a sectional view taken along the line CC in FIG.

FIG. 3 is a sectional view taken along a line DD in FIG. 1;

FIG. 4 is a partially enlarged perspective view illustrating a method of forming a liquid flow path.

FIG. 5 is a partially broken perspective view illustrating a filtration method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Frame 1a, 1b Hollow part (of frame) 2a, 2b Filtration membrane 3a, 3b Supporting member 4a, 4b Suction pipe (suction port) 5a, 5b Vertical flow path (liquid flow path) 5c Horizontal flow path (liquid flow path) 6a, 6b Communication port 7a, 7b Connection flow path 8a, 8b Air vent 10 Flat membrane filter 11 Suction header 12 Filtration tank 13 Supply pipe 14 Water level gauge

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D006 GA02 HA41 HA93 HA95 JA03C JA08A JA08C JA20A JA51Z KE21Q MA03 MA31 PA02 PB08 PC62

Claims (8)

[Claims] 1. A method according to claim 1, further comprising: attaching a filtration membrane so as to cover a hollow portion formed in the frame, and having a suction port communicating with the hollow portion, and immersing the liquid into the liquid to suck the liquid from the suction port. In a flat membrane filter that performs solid-liquid separation,
A flat membrane filter, wherein a communication port between the hollow portion and the suction port is provided only at a bottom portion of the frame. 2. The flat membrane filter according to claim 1, wherein an air vent communicating with the hollow portion is provided at a head of the frame. 3. The flat membrane according to claim 1, wherein the suction port is provided in a head of the frame, and a liquid flow path connecting the suction port and the communication port is formed in a peripheral portion of the frame. filter. 4. The flat membrane filter according to claim 3, wherein the liquid flow path comprises a groove formed on the end face on the frame body side and a lid for covering the groove densely. 5. A frame according to claim 1, wherein a plurality of hollow portions are formed in said frame, and a connecting flow path communicating each hollow portion is provided.
5. The flat membrane filter according to 3 or 4. 6. The flat membrane filter according to claim 1, wherein the hollow portion is a hole penetrating the frame, and filtration membranes are attached to both sides of the frame. 7. A filtering method for separating a liquid to be treated by a flat membrane filter immersed therein into a solid-liquid separation, wherein a filtration tank for the liquid to be treated is provided, and said filtration tank is provided in said filtration tank. The flat membrane filter according to 5 or 6 is immersed in a semi-submerged state, liquid is sucked to perform solid-liquid separation, and the clogging of the flat membrane filter can be determined by the rise in the water level of the filtration tank. A method for filtering a liquid, comprising: 8. The method for filtering a liquid according to claim 7, wherein a water level detecting means for said filtration tank is provided, and a signal is issued when a predetermined water level is reached.