JP3835511B2 - Concentrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a concentration device for difficult-to-filter sludge such as sewage sludge, and more particularly to improvement of a device for discharging a separation liquid by immersing a filtration chamber provided with a filter medium in a concentration tank.
[0002]
[Prior art]
Conventionally, a filtration concentrator that concentrates the sludge in a filtration tank by suspending a filter that forms a filtration chamber by combining two filtration nets in a sludge chamber of the filtration tank and taking out moisture in the sludge into the filtration chamber, for example, This is known as described in JP-B-63-13721. Moreover, the applicant has also proposed an apparatus for taking out and washing the filter cloth stretched on the filtration surface of the filtration chamber outside the concentration tank in Japanese Utility Model Publication No. 2-27853 .
[0003]
[Problems to be solved by the invention]
However, in the case of using a filter cloth as the conventional filter medium, the cake attached to the filter cloth is difficult to peel off, and the clogged filter cloth can be backwashed by supplying compressed air from the inside of the filtration chamber. Compressed air was missing from the surface of some of the filter media, and sufficient cleaning could not be performed, making it difficult to remove clogged material. Therefore, in the case where the filter cloth stretched in the filtration chamber is run to regenerate the filter cloth outside the concentration tank, a device for running the filter cloth in water and great power are required. The present invention provides a concentrating device using a filter medium having good cake peelability without running the filter medium in water.
[0004]
[Means for Solving the Problems]
The gist of the present invention is that the filter plate is immersed in the concentration tank, the sludge supply pipe and the concentrate discharge pipe are connected to the concentration tank, and the separation liquid discharge pipe is connected to the filter plate. A pressure tank having a large number of small holes on its surface is installed in the filtration chamber, a gap is provided between the filter medium surface of the filtration chamber and the surface of the pressure tank, and a compressed air pipe is connected to the pressure tank. Compressed air is blown from the small holes on the peripheral surface of the pressure tank to the filter medium surface of the filtration chamber. The filter plate is a support plate having a large number of through holes and a metallic metal screen with good peelability. A preferred filter medium is one in which a plurality of metal screens are stretched on a support plate, and metal screens are overlapped to make the filter screen fine. Specifically, the top of the metal screen is made finer so that the filtrate can be drawn out more easily. The coarse screen is laid on the support plate, and the middle screen is placed on the upper intermediate layer. A fine screen is stretched on the surface layer. Further, the through holes of the support plate are slits having a wedge-shaped cross-sectional area, and the screen eyes are successively made finer from the inside of the filtration chamber to facilitate backwashing.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The apparatus according to the present invention is configured as described above. When sludge is supplied from the sludge supply pipe to the concentration tank, the filter plate is immersed in the concentration tank, and the separation liquid is discharged from the discharge pipe of the filtration chamber, the sludge is As a result, 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, when compressed air is pressed into the pressure tank, the compressed air is injected from the small hole of the pressure tank toward the back of the mesh screen of the opposing filtration chamber, and the filterability A good filtration surface can be backwashed with compressed air and regenerated. Again, sludge is supplied to the concentration tank and sludge concentration is started.
[0006]
【Example】
The filter medium of the filter according to the present invention will be described in detail with reference to the drawings. First, in FIG. 1, reference numeral 1 is a concentration tank, and a sludge supply pipe 2 and a concentration tank 1 are disposed on the upper side wall of the concentration tank 1. A concentrate extraction pipe 3 is connected to the bottom of the tank, and automatic valves V1 and V2 are provided on the sludge supply pipe 2 and the concentrate extraction pipe 3, respectively. A plurality of filtration plates 4 are arranged in parallel in the concentration tank 1, and a siphon-like separation liquid discharge pipe 5 is connected to the filtration board 4, and the discharge pipe 5 is connected to the concentration pipe 1 due to a difference in water level with the concentration tank 1. An automatic valve V3 is provided. 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 comprises a rectangular box-shaped support plate 6 and a metallic metal screen 7 stretched on the support plate 6. A filtration chamber 8 is formed inside 4.
[0007]
The filter plate 4 will be described in further detail. As shown in FIG. 4, the support plate 6 has a large number of through holes 6a. The through holes 6a of the support plate 6 have a wedge shape in cross section and form slits in plan view. is doing. The metal screen 7 stretched on the support plate 6 has a coarse screen 7a laid on the support plate 6, an intermediate screen 7b interposed in an intermediate layer above it, and a fine screen 7c stretched on the surface layer. The eyes of the metal screens 7a, 7b, and 7c that are overlaid are made finer as the upper surface layer. By laminating filter media, the screen becomes finer, and small particles can be captured to increase the recovery rate. And the strength of the filter medium is increased. The eyes of these screens can change the aperture of the screen according to the degree of difficulty of filterability of the stock solution or the particle size of the solid matter. As for the aperture of the screen, the coarse screen 7a is 500 μm to 1. It is conceivable that the intermediate screen 7b of the intermediate layer on the upper side thereof is 100 μm to 1.0 mm and the fine screen 7c of the surface layer is in the range of 20 μm to 0.5 mm, and a metal screen 7a having an arbitrary diameter depending on the target stock solution. , 7b, 7c may be combined. A plurality of metal screens 7 supported by the support plate are superposed to withstand high pressure and to cope with high dehydration work. The filter plate 4 may be reinforced by laying a punching metal 13 on the inner peripheral surface of the support plate 6.
[0008]
As shown in FIGS. 2 and 5, a pressure tank 9 having a large number of small holes 9 a... Is provided in the surface of the filtration chamber 8 of the filter plate 4. Nine small holes 9a are made to approach and face each other. A compressed air pipe 10 is connected to the pressure tank 9, and the compressed air pipe 10 is connected to an air compressor 11 via an automatic valve V4. When the metal screen 7 is clogged, if the compressed air is jetted, the compressed air is blown directly into the screen from the back surface of the metal screen 7, and the clogging material is removed from the metal screen 7 having a good peeling system. Can do. The opening of the filtrate discharge pipe 5 is provided at the side end of the filtrate chamber 8 in which the pressure tank 9 is provided, and the end of the discharge pipe 5 is opened to the filtrate storage tank 12.
[0009]
The operation procedure of the concentration apparatus according to the present invention will be described. (1) Concentration step: First, the automatic valve V2 of the concentrated sludge discharge pipe 3 is closed, the automatic valve V3 of the separation liquid discharge pipe 5 is closed, and the compressed air pipe When the automatic valve V4 of 10 is closed and the automatic valve V1 provided in 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 precipitates 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 the difference in water level. Then, after a predetermined time, the automatic valve V1 of the sludge supply pipe is closed, and the inflow of sludge into the concentration tank 1 is stopped. (2) Concentrated sludge discharge process: When the separation liquid is continuously discharged from the filtration chamber 8, the sludge is sequentially concentrated, and eventually the cake adheres to the metal screen 7 and the filtration performance decreases. The automatic valve V2 of the concentrated sludge take-out pipe 3 is opened, and the concentrated sludge is discharged from the take-out pipe 3 of the concentration tank 1. (3) Filter medium backwashing process: After discharging sludge in the concentration tank 1, the automatic valve V4 of the compressed air pipe 10 is opened, and the air compressor 11 is driven to press-fit the compressed air into the pressure tank 9. Compressed air is jetted from the back surface of the metal screen 7 of the filter plate 4 facing from a plurality of small holes 9a, and the metal screen 7 is regenerated by backwashing the metal filtration surface with good filterability with compressed air. be able to. The cleaning water may be supplied from the separation liquid discharge pipe 5 to the filtration chamber 8 for cleaning the dirty filtration surface of the metal screen 7 and discharging the separated sludge from the concentration tank 1. . And again, sludge can be supplied to a concentration tank and sludge concentration can be started.
[0010]
【The invention's effect】
As described above, the filter plate of the concentrator of the present invention has a plurality of metallic metal screens superimposed on a support plate having a large number of through holes, and a finer screen is superimposed on the upper surface layer. The screen becomes finer and fine filtration is possible, and the strength of the filter medium is increased. And in the case of using a filter cloth as a conventional filter medium, even if the compressed air is supplied to the clogged filter cloth and backwashed, the compressed air will pass through a part of the filter medium surface, resulting in clogging. However, in the filter plate of the present invention, a pressure tank having many small holes is provided on the back surface of the metal screen, so that compressed air is blown directly into the metal screen. The cake can be peeled off from a metal screen with good peelability, which facilitates reverse cleaning.
[Brief description of the drawings]
FIG. 1 is a perspective view of a concentrating device according to the present invention.
FIG. 2 is a conceptual vertical side view of a filter plate having 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 side view of the filter medium similarly disposed on the filter plate.
FIG. 5 is a longitudinal side view of the concentrator.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Concentration tank 2 Supply pipe 3 Extraction pipe 4 Filtration plate 5 Discharge pipe 6 Support plate 6a Through hole 7 Metal screen 7a Rough screen 7b Medium screen 7c Fine screen 8 Filtration chamber 9 Pressure tank 9a Small hole 10 Compressed air pipe

Claims (5)

  The filter plate (4) is immersed in the concentration tank (1), the sludge supply pipe (2) and the concentrate discharge pipe (3) are connected to the concentration tank (1), and the separation liquid is connected to the filter plate (4). In the apparatus to which the discharge pipe (5) is connected, a pressure tank (9) having a large number of small holes (9a ...) on its surface is installed in the filtration chamber (8) of the filtration plate (4), and the filtration chamber ( A concentrating device characterized in that a gap is provided between the filter medium surface of 8) and the surface of the pressure tank (9), and a compressed air pipe (10) is connected to the pressure tank (9).   2. The metal plate (7a, 7b, 7c) is stretched around a support plate (6) having a large number of through holes (6a) in the filter plate (4). Concentration device.   The filter medium stretched on the support plate (6) is composed of a plurality of metal screens (7a, 7b, 7c), and the eyes of the superimposed metal screens (7a, 7b, 7c) are made finer as the upper surface layer. The concentrator according to claim 2.   The superposed metal screens (7a, 7b, 7c) are provided with a coarse screen (7a) on the support plate, and a middle screen (7b) is interposed in the upper intermediate layer, with fine meshes on the surface layer. The concentrating device according to claim 2 or 3, wherein a screen (7c) is stretched. The concentrating device according to any one of claims 2 to 4, wherein the through hole (6a) of the support plate (6) is a slit having a wedge-shaped cross-sectional area.

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