JPH0487606A - Expanding and contracting filter - Google Patents

Abstract

PURPOSE:To prevent the clogging of a filter by wrapping a filtrate collecting member in a filter consisting of a flexible filter sheet by the inward pressure of the filter in filtration, flattening the filter and expanding the filter by the outward pressure of the filter when the cake is released. CONSTITUTION:This filter is formed by a cylindrical or bag-shaped filter 5 consisting of a flexible filter sheet 1 and a filtrate collecting member 6 inserted into the filter 5 and with one end projecting outside the filter. The collecting member 6 is wrapped in the filter 5 by the inward pressure of the filter 5 in filtration, and the filter is flattened. Conversely, the filter is expanded by the outward pressure of the filter 5 when the cake is released. A filtrate guide passage 9 opened in the filter 5 and used for sending the filtrate in the filter 5 outside the filter 5 is provided to the collecting member 6. Consequently, the clogging of the filter due to the deposition of oxides in filtration is prevented, and the cake is sufficiently and surely released.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to the filtration or concentration of suspensions generated during the purification of various industrial waste liquids and sewage water, etc. It relates to filters used for collecting materials, etc.

(Prior art) Conventionally, this type of filter has been constructed by covering the outer circumferential surface of a hollow cylindrical body made of hard synthetic resin with a large number of liquid passage holes on its curved surface via a spacer such as a net. A double-tube structure with a filtrate collection tube inserted into the cylinder, a double-tube structure with the filtrate collection tube removed, or a porous hollow cylinder made of a hard material such as ceramic. There are single-tube structures such as those in which the porous surface constitutes a filter, and in use, these filters are installed in a processing tank and the stock solution that is pumped to the outside of the filter is filtered.
The filter slag is captured on the outer surface of the filter, and the filtrate is taken out of the tank through the hollow cylindrical body.After the required filtration, the filter slag accumulated on the filter outer surface is removed from the inside of the filter using the pressurized air sent into the hollow cylinder. A method is used in which the filter is peeled off from the outer surface of the filter by flowing back to the outside and taken out of the tank.

(Problems to be Solved by the Invention) However, in these conventional devices, oxidizable substances such as iron ions and manganese ions dissolved in the filtrate during filtration remain in the air in large quantities inside the cylindrical body on the inner surface of the filter. Oxidized and precipitated by oxygen, this adheres to the inner surface of the filter and causes clogging, which reduces the filtration ability of the filter and significantly shortens its life. With the conventional method that relies only on backflow, sufficient filtrate separation cannot be obtained. In particular, if there is early separation in a part of the filtrate reservoir on the outer surface of the filter, pressurized air will intensively flow out from that part, resulting in unresolved sludge. In many cases, peeled parts remain, and as mentioned above, when the filter becomes clogged due to oxidation and precipitation of oxidized substances, the blowing of pressurized air through the filter decreases, reducing the filter slag peeling effect. As a result, unseparated filter slag builds up, which together significantly reduces the performance, economical efficiency, etc. of the filter.

An object of the present invention is to prevent clogging of a filter due to oxidation and precipitation of oxidized substances during filtration, and to realize sufficiently reliable separation of filter dregs.

(Means for Solving the Problems) As a means for solving the above problems, the present invention comprises a cylindrical or bag-shaped filter, and a filtrate collecting member inserted into the filter and having one end protruding outside the filter. The filter is made of a flexible filtration sheet, which wraps around and flattens the filtrate collection member by applying pressure from the outside to the inside of the filter during filtration, and flattens the filter from the inside to the outside when peeling off the filter cake. It is deformable so that it expands when pressure is applied to it.

The present invention proposes an expansion and contraction type filter in which the filtrate collection member has a filtrate guide path that opens into the filter and guides the filtrate in the filter to the outside of the filter.

In the present invention, the above-mentioned "cylindrical filter J" refers to a filter that maintains a substantially cylindrical shape such as a cylinder, an elliptical cylinder, or a rectangular cylinder in a normal state where no pressure is applied. It means a filter that maintains a nearly flat bag-like shape.

The above-mentioned "flexible filtration sheet" includes flexible sheets made of cloth, nonwoven fabric, paper, and other various materials that have filtration ability.

(Function) In the expansion type filter of the present invention configured as described above, when the stock solution is supplied to the outer surface of the filter by pressure from outside to inside of the filter due to positive pressure from outside the filter or negative pressure from inside the filter, The cylindrical or bag-shaped filter wraps around the filtrate collecting member due to the above pressure and contracts into a flat shape, and filtration is started in a state where most of the air inside the filter is eliminated,
This sufficiently suppresses iron ions, manganese ions, etc. in the filtrate from being oxidized and precipitated on the inner surface of the filter. When removing filter slag from the outer surface of the filter,
When pressurized air is sent into the filter and pressure is supplied from the inside to the outside of the filter, the filter, which had been flattened and contracted, rapidly expands and fluctuates, and at the same time, this fluctuating impact on the filter surface is applied to the filter slag on the outside of the filter. , pressurized air flows back into the filter from the inside to the outside, and this interaction ensures that the filter slag that adheres to the outside of the filter is removed from the filter! 1
Let go.

Embodiments of the present invention will be described below with reference to the drawings.

(Example) In Fig. 1.2, short cylindrical caps (2) are attached to both opening ends of a hose-like flexible filter sheet (1) made of cotton cloth.
(3), and both caps (2),
(3) are respectively tightened with bands (4), thereby forming a cylindrical filter (5), and inside such a filter (5), a filtrate collection tube (6) with open ends is inserted.
) is passed vertically through the center of the cap (2) at one end and close to the cap (3) at the other end, and a protrusion (7) of an appropriate length is protruded from the cap (2) at one end. Then, it is fixed to the cap (2) watertightly by adhesion, welding, etc. (7).

The filtrate collection W (6) has a filtrate collection port (8
)... are opened, and the vertical hole in the collection W (6) is used as a filtrate guide path (9) to communicate between the inside and outside of the filter (5) through the open end of the protrusion (W). (1
0) is a male thread provided on the protrusion (7). A large number of filters having the above-mentioned structure can be connected, for example, to a partition plate (11) that divides the inside of the processing tank into an upper chamber and a lower chamber with the protrusion (7).
from bottom to top, and insert a nut (
12) and hang it in the lower chamber. (13) is the backing.

In use, the stock solution is pumped into the lower chamber, thereby supplying the stock solution to the outer surface of the filter (5) under positive pressure, so that the cylindrical flexible filter sheet (1) removes the air inside and presses the stock solution as shown in Figure 2a. The sheet (1) wraps around the filtrate collection tube (6) and shrinks into a flat shape, with the inner surfaces of the sheets overlapping each other in the portion of the sheet (1) that does not touch the filtrate collection tube (6). Filtration begins in a flat state containing almost no . The stock solution is filtered through the entire surface of the flattened filter sheet (1), the filter cake is captured on the outer surface of the sheet (1), and the filtrate immediately passes through the filtrate collection port (8) at the part that wraps around the filtrate collection tube (6). )
The filtrate flows into the filtrate guide path (9) through the polymerized portion of the inner surface of the sheet, and through the minute gap in the polymerized portion to the filtrate collection pipe (6), and similarly flows from the collection port (8) to the guide path (9). As a result, the filtrate hardly comes into contact with air at the stage when it oozes out onto the inner surface of the filter sheet (1).
Therefore, iron ions, manganese ions, etc. in the filtrate hardly cause oxidized precipitates to adhere to the inner surface of the filter sheet (1). The filtrate sent into the collecting pipe (6) is sent to the upper chamber through the filtrate guide path (9), and there taken out to the outside of the processing tank through appropriate piping.

After the required amount of filtration has passed, in the step of peeling off the filter slag that has adhered and accumulated on the outer surface of the filter (5), the protrusion (
7) When pressurized air is blown into the collection pipe (6) from the open end, the air blown out from the filtrate collection port (8) and the lower end of the pipe (6) opens into a flat filtration state. The sheet (1) is rapidly expanded into a cylindrical shape as shown in the second figure, and at the same time air is blown from the inside to the outside through the filter sheet (1). Thoroughly peel off the filter cake on the outside.

The filtrate collection pipe (6) on the upper side can be replaced with collection pipes (6a) and (6b) as shown in Figure 3.4.
The collection pipe (6a) shown in the figure has four filtrate guide paths (9a) consisting of grooves extending the entire length in the generatrix direction on its outer surface, and has 8
The open groove mouth of the groove corresponds to the filtrate collection port (8a), and the collection pipe (6b) in FIG. Mouth (8b
), and the inside of the tube is used as a filtrate guide path (9b). (15a) and (15b) are collection pipes (6a) and (6
b) A sleeve fitted over the upper end of the sleeve, which is used to secure the cap (2) in Fig. 1 and to secure the partition plate (
11) is recommended.

Another embodiment shown in Fig. 5.6 has two grooves (16c), (], 6c) in the generatrix direction on the peripheral wall of the portion of the filtrate collection tube (6c) located inside the filter (5c). A rectangular plate-shaped spacer (17c) made of a corrugated plate is fitted into the middle part of the spacer (17c), and the spacer (17c)
and the collection tube (6c) are tied together with a string (18c), and the collection tube (6c) with a spacer is inserted into the cylindrical filter (5c).The other structure is substantially the same as in Fig. 1.2. In the same example,
During positive pressure filtration, the cylindrical filter sheet (1c) is easily flattened using the spacer (7c) as support, and also intervenes in the polymerized portion of the inner surface of the sheet (1c) to promote flow of the filtrate.

The filter shown in Figure 7.8 is a bag-like filter (5d) made by sewing a flexible filter sheet (1d) made of non-woven fabric into a flat bag shape.
), insert the filtrate collection tube (6d) from one end into the bag-like filter, fasten one end of the filter (5d) to the collection tube (6d) with a band (4d), and The structure of is substantially the same as in FIG. 1.2. In addition, (19d
), the backing receiver fixed to the protrusion (7d) of the collection pipe (6d) is a flange. According to this example, during filtration by force-feeding the stock solution, the bag-shaped filter (5d) becomes further flattened as shown by the solid line in Figure 8a, and when the filter cake is peeled off by back-feeding pressurized air, as shown by the phantom line in the figure. Expands into a cylindrical shape.

Another embodiment shown in FIG. 9 is a filtrate collection rod ( 6e), a spacer-equipped filtrate collection rod (6e) holding a spacer (17e) similar to that shown in Fig. 5.6 is used, and the other structures are substantially the same as in Figs. 7 and 8. be. In this example, the longitudinal grooves and spaces formed between adjacent rods also form the filtrate guide path (9e). Incidentally, it is preferable to provide a sleeve similar to that shown in Fig. 3.4 at the upper end of the collecting rod (6e).

Still another embodiment shown in FIG. 10 uses a spacer (17f) and filtrate collecting plate (6f), which is formed by providing filtrate guide paths (9f) consisting of vertical grooves on both sides of a rectangular plate. , the other structure is substantially the same as in FIG. 7.8.

The spacer and filtrate collection plate on the upper side is a three-way radial spacer (17g) and filtrate collection plate (as shown in Figure 11).
6g), and in this case, a bag-shaped filter (5g) is often used.
g) is sewn (20 g) to each radial tip of the above radial spacer/filtrate collection plate (6 g) so that it is flattened and expanded at the inner corner of the adjacent radial plate. be.

In addition, if the filter does not expand rapidly and sufficiently even if the pressurized air for removing the filtrate is sent back into the filter through the filtrate collecting member on each side, use a dedicated pressurizer for the filter. The twelfth method may be one in which an air supply pipe is connected, or the upper end of the filter is opened to an upper chamber through a partition plate, and a pressurized air supply pipe is connected to the upper chamber.
The figure shows the latter example, with the cap (2h) opening into the upper chamber.

(Effects of the Invention) According to the expansion filter of the present invention, when filtration is performed by supplying the stock solution to the filter by applying pressure from the outside to the inside of the filter, the filter contracts into a flat shape to expel the air inside. This suppresses the oxidation and precipitation of iron ions, manganese ions, etc. in the filtrate on the inner surface of the filter, and sufficiently prevents clogging of the filter.
Moreover, when peeling filter slag by backflow of pressurized air from inside to outside of the filter, the fluctuation impact of the filter surface due to the rapid expansion of the flattened filter and the backflow of pressurized air cause the outer surface of the filter to be damaged. Adhering filter dregs can be peeled off with sufficient certainty.

[Brief explanation of the drawing]

The drawings show the actual embodiment; FIG. 1 is a longitudinal sectional front view of the filter, FIG. 2 is an enlarged sectional view taken along the line T in FIG. 1, FIG. .4 is an enlarged partially omitted slope view of another example of the filtrate collection pipe, FIG. 5 is an enlarged cross-sectional view of another example of the filter, and FIG. Fig. 7 is a longitudinal sectional front view of another embodiment of the filter, and Fig. 8 is a partially omitted enlarged slope view of the filtrate collection pipe.
■ An enlarged cross-sectional view of the line, Fig. 8a is a cross-sectional view of the same as above in a flat contracted state, Fig. 9 is an enlarged cross-sectional view of yet another embodiment of the filter;
FIG. 10 is an enlarged cross-sectional view of a different embodiment of the filter;
FIG. 1 is an enlarged cross-sectional view of yet another embodiment of the filter, and FIG. 12 is a longitudinal sectional front view of another embodiment of the filter. 1.1a, 1b, 1c, 1d, 1e, 1f, 1 g-・
・Flexible filter sheet, 5, 5a, 5b, 5c...Tubular filter, 5d, 5e, 5f, 5g...Bag filter, 6.6a, 6b, 6c, 6d ・=Filtrate collection tube ,
6e...filtrate collection rod, 6f, 6g...filtrate collection plate,
9.9a, 9b, 9c, 9d, 9e, 9f, 9g...
Filtrate guideway.

Claims (1)

[Scope of Claims] Consisting of a cylindrical or bag-shaped filter, and a filtrate collection member inserted into the filter and having one end protruding outside the filter, the filter is composed of a flexible filter sheet, and during filtration, The filtrate collecting member is wrapped and flattened by the pressure from outside to the inside of the filter, and is deformable so as to expand by the pressure from the inside to the outside of the filter when peeling the filtrate, and the filtrate collection member The collection member has a filtrate guide path that opens into the filter and guides the filtrate in the filter to the outside of the filter.