JP2001145899A - Concentration apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a concentration apparatus wherein a filter plate is immersed in a concentration tank to discharge a separated liquid from hardly filterable sludge such as sewage sludge or the like and the peelability of a cake is enhanced. SOLUTION: In a concentration apparatus wherein a filter plate 4 is immersed in a concentration tank 1 and a sludge supply pipe 2 and a concentrated liquid tanking-out pipe 3 and connected to the concentration tank 1 and a separated liquid discharge pipe 5 is connected to the filter plate 4, a pressure tank 9 having a large number of small holes 9a... formed on the surface thereof is disposed in the filter chamber 8 of the filter plate 4 and a gap is formed between the surface of the filter medium of the filter chamber 8 and the surface of the pressure tank 9 and a compressed air pipe 10 is connected to the pressure tank 9. Since the pressure tank having a large number of the small holes is disposed in opposed relation to the rear surface of the filter medium, compressed air is directly blown in the meshes of a screen to peel a cake from the screen. As the filter medium, metal screens 7a, 7b, 7c good in peelability are arranged in a superposed state and the filtering meshes thereof are made fine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for concentrating hard-to-filter sludge such as sewage sludge, and more particularly, to an apparatus for discharging a separated liquid by immersing a filtration chamber in which a filter medium is stretched in a concentration tank. About.

[0002]

2. Description of the Related Art Conventionally, a filter in which a filtration chamber is formed by combining two filtration nets is suspended in a sludge chamber of a filtration tank, and water in the sludge is taken out into the filtration chamber to concentrate the sludge in the filtration tank. Concentrators are known, for example, as described in JP-B-63-13721. In addition, the applicant proposes a device for removing the filter cloth stretched on the filtration surface of the filtration chamber to the outside of the concentration tank and washing the filter cloth in Japanese Patent Publication No. 2-27853.

[0003]

However, in the above-mentioned conventional filter medium using a filter cloth, cake adhering to the filter cloth is difficult to peel off, and the clogged filter cloth is removed from the inside of the filtration chamber by compressed air. , The compressed air leaked through some of the filter media surfaces, and sufficient washing could not be performed, making it difficult to remove clogs. For this reason, in the apparatus in which the filter cloth stretched in the filtration chamber is run to regenerate the filter cloth outside the concentration tank, a device for moving the filter cloth in water and a large power are required. SUMMARY OF THE INVENTION The present invention provides a concentrating device using a filter medium having good cake releasability without running the filter medium in water.

[0004]

The gist of the present invention is that a filter plate is immersed in a concentration tank, a sludge supply pipe and a concentrate discharge pipe are connected to the concentration tank, and a separation liquid discharge pipe is connected to the filter plate. In the connected device, a pressure tank having a large number of small holes is provided inside the filtration chamber of the filtration plate, and a gap is provided between the filter medium surface of the filtration chamber and the surface of the pressure tank. A compressed air pipe is connected, and compressed air is blown from a small hole on the peripheral surface of the pressure tank to the filter medium surface of the filtration chamber. The filter plate has a support plate having a large number of through holes and a metal screen with good releasability stretched over the support plate. A preferred filter medium is one in which a plurality of metal screens are stretched on a support plate, and the metal screens are superposed to reduce the filtration mesh. Specifically, the mesh of the superposed metal screen is made finer to the upper layer to facilitate the extraction of the filtrate.A rough screen is laid on the support plate, and a middle screen is interposed on the intermediate layer above it. And a fine screen stretched over the surface layer. In addition, the through hole of the support plate is a slit having a wedge-shaped cross-sectional area, and the mesh of the screen is sequentially made finer from the inside of the filtration chamber to facilitate backwashing.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The apparatus according to the present invention is constructed as described above. Sludge is supplied from a sludge supply pipe to a thickening tank, a filter plate is immersed in the thickening tank, and a sludge is discharged from a discharge pipe of a filtering chamber. When the separated liquid is discharged, the sludge is concentrated, the cake adheres to the mesh screen, and the filtration performance decreases. After extracting the concentrated sludge from the extraction pipe of the concentration tank, pressurized air is injected into the pressure tank, and compressed air is injected from the small hole of the pressure tank toward the back surface of the mesh screen of the opposite filtration chamber, and the filterability is improved. Good filtration surface can be regenerated by backwashing with compressed air. Again, sludge is supplied to the concentration tank to start sludge concentration.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A filter medium of a filter according to the present invention will be described in detail with reference to the drawings. First, in FIG. 1, reference numeral 1 denotes a thickening tank, and a sludge supply pipe 2 is provided above a side wall of the thickening tank 1.
And a concentrated liquid take-out pipe 3 connected to the bottom of the condensing tank 1. An automatic valve V 1 is connected to the sludge supply pipe 2 and the concentrated liquid take-out pipe 3.
V2 is provided. A plurality of filter plates 4 are arranged side by side in the concentration tank 1, and the sieve-like discharge pipe 5
Are connected to each other, and the discharge pipe 5
Is provided with an automatic valve V3. In addition, the discharge pipe 5 connected to the filter plate 4 may be discharged through the concentration tank 1 as shown in FIG. As shown in FIGS. 1 and 2, the filter plate 4 is a rectangular box-shaped support plate 6.
And a metal screen 7 stretched over a support plate 6, and a filtration chamber 8 is formed inside the filtration plate 4.

The filter plate 4 will be described in more detail.
As shown in the figure, the support plate 6 has a large number of through holes 6a, and the through holes 6a of the support plate 6 have a wedge-shaped cross section and form a slit in plan view. The metal screen 7 stretched on the support plate 6 is a rough screen 7 laid on the support plate 6.
a, a middle screen 7b is interposed in the upper intermediate layer, a fine screen 7c is stretched in the surface layer, and the eyes of the superposed metal screens 7a, 7b, 7c are made finer toward the upper surface layer. In addition, by laminating the filter media, the mesh of the screen becomes finer, small particles can be captured, the recovery rate can be increased, and the filter media strength is also increased. The eyes of these screens can change the aperture of the screen by the difficulty of filtration of the stock solution or by the particle size of the solid material.
The coarse screen 7a has a thickness of 500 μm to 1.5 mm, and the intermediate screen 7b on the upper portion has a thickness of 100 μm to 1.0 mm.
mm, the fine screen 7c of the surface layer is 20 μm to 0.5 μm.
It is possible to combine metal screens 7a, 7b, 7c of any diameter according to the target stock solution. Then, the plurality of metal screens 7 supported by the support plate are superimposed to withstand a high pressure and can cope with a high dehydration operation. In addition, a perforated metal 13 may be laid on the inner peripheral surface of the support plate 6 to reinforce the filter plate 4.

As shown in FIGS. 2 and 5, a pressure tank 9 having a large number of small holes 9a is internally provided in the filtration chamber 8 of the filtration plate 4. And the small hole 9a of the pressure tank 9 are brought close to each other and opposed to each other. A compressed air pipe 10 is connected to the pressure tank 9.
0 is connected to the air compressor 11 via an automatic valve V4. Then, when the metal screen 7 is clogged, if compressed air is injected, the compressed air is directly blown into the eyes of the screen from the back surface of the metal screen 7 to remove the clogged material from the metal screen 7 with good peeling ability. Can be. The starting end opening of the filtrate discharge pipe 5 is provided at a side end of a filtrate chamber 8 in which a pressure tank 9 is provided.
Is open to the filtrate storage tank 12.

The operation of the concentrating apparatus according to the present invention will be described. Concentrating step: First, the automatic valve V2 of the concentrated sludge discharge pipe 3 is closed, the automatic valve V3 of the separated liquid discharge pipe 5 is closed, and the compressed air pipe is closed. When the automatic valve V4 of 10 is closed and the automatic valve V1 provided on the sludge supply pipe is opened to supply sludge to the concentration tank 1 and the filter plate 4 is immersed in the concentration tank 1, the sludge water level of the concentration tank 1 is reduced. Due to the head pressure, the filtrate passes through the metal screen 7 of the filter plate 4 and flows into the filtration chamber 8, and the solid content is blocked by the metal screen 7 and settles at the bottom of the tank. The separated liquid flowing into the filtration chamber 8 is discharged from the discharge pipe 5 to the filtrate storage tank 12 due to a difference in water level. Then, after a predetermined time, the automatic valve V1 of the sludge supply pipe is closed, and the inflow of the sludge into the concentration tank 1 is stopped. Condensed sludge discharge step: When the separated liquid is continuously discharged from the filtration chamber 8, the sludge is sequentially concentrated, and the cake adheres to the metal screen 7 and the filtration performance is reduced. The automatic valve V2 of the concentrated sludge discharge pipe 3 is opened, and the concentrated sludge is discharged from the discharge pipe 3 of the concentration tank 1. Backwashing process of filter media: After discharging sludge from the thickening tank 1, the automatic valve V of the compressed air pipe 10
4, the compressed air is pressed into the pressure tank 9 by driving the air compressor 11, and a number of small holes 9a in the pressure tank 9 are formed.
Then, compressed air is injected from the back surface of the metal screen 7 of the filter plate 4 facing the filter screen, and the metal screen 7 having good filterability can be backwashed with the compressed air to regenerate the metal screen 7. In order to wash the dirty filtration surface of the metal screen 7 and discharge the separated sludge from the concentration tank 1, the washing water may be supplied to the filtration chamber 8 from the separation liquid discharge pipe 5. . Then, sludge can be supplied to the concentration tank again to start sludge concentration.

[0010]

As described above, the filter plate of the concentrator according to the present invention has a plurality of metallic metal screens stacked on a support plate having a large number of through-holes, and a finer screen is formed on the upper surface layer. Since the screens are superposed, the screen becomes finer and fine filtration becomes possible, and the filter medium strength is increased. And, in the case of using a filter cloth as a conventional filter medium, even if compressed air is supplied to the clogged filter cloth and backwashed, the compressed air passes through a part of the filter medium surface and the clogged material is clogged. Although it was difficult to remove the filter, the filter plate of the present invention provided a pressure tank having a number of small holes on the back of the metal screen, so that compressed air was directly blown into the eyes of the metal screen. The cake can be peeled off from the metal screen having good peelability, and the backwashing and purification can be easily performed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a concentration device according to the present invention.

FIG. 2 is a conceptual vertical sectional side view of a filter plate provided with a pressure tank according to the present invention.

FIG. 3 is a perspective view showing another embodiment of the concentrator.

FIG. 4 is a conceptual vertical sectional side view of a filter medium provided on the filter plate.

FIG. 5 is a vertical sectional side view of the concentrating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Concentration tank 2 Supply pipe 3 Extraction pipe 4 Filter plate 5 Discharge pipe 6 Support plate 6a Through hole 7 Metal screen 7a Coarse screen 7b Medium screen 7c Fine screen 8 Filtration chamber 9 Pressure tank 9a Small hole 10 Compressed air pipe

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 29/38 520A 530A 540

Claims (5)

[Claims] 1. A filter plate (4) is immersed in a concentration tank (1), and a sludge supply pipe (2) and a concentrated liquid extraction pipe (3) are connected to the concentration tank (1). ) Is connected to a separation liquid discharge pipe (5), and a pressure tank (9) having a large number of small holes (9a...) On its surface is installed in a filtration chamber (8) of the filtration plate (4). A concentrating device characterized by providing a gap between the surface of the filter medium (9) and the filter medium surface of the filtration chamber (8), and connecting a compressed air pipe (10) to the pressure tank (9). 2. The filter plate (4) has a large number of through holes (6a).
2. The concentrator according to claim 1, wherein a metal screen (7a, 7b, 7c) made of metal is stretched on the support plate (6) having (...). 3. The filter medium stretched on the support plate (6) comprises a plurality of metal screens (7a, 7b, 7c).
3. The concentrator according to claim 2, wherein the superposed metal screens (7a, 7b, 7c) have finer eyes toward the upper surface layer. 4. The superposed metal screen (7a,
7b, 7c) lay a coarse screen (7a) on a support plate, interpose a medium screen (7b) on an intermediate layer above the support screen, and stretch a fine screen (7c) on a surface layer. The concentrator according to claim 2 or 3, wherein: 5. The concentrator according to claim 1, wherein the through hole (6a) of the support plate (6) is a slit having a wedge-shaped cross-sectional area.