JPH08108016A - Filter medium clogging preventive device in vacuum dehydrator for water-containing material - Google Patents

Abstract

PURPOSE: To prevent the clogging of a filter medium even for a material to be treated having high viscosity or the one containing fine particles by installing a bubble discharging device for feeding many small bubbles onto the outer surface of a filter medium of a filter hollow body immersed in an original liquid in an original tank. CONSTITUTION: Below both the right and left sides viewed from the circular side face of the back surface of a filter cylindrical body 11 immersed in an original liquid 7 in an original liquid tank 6, bubble discharging pipes 11 consisting of porous unglazed pottery are arranged parallel over the total length in the axial direction of the filter cylindrical body 1, and one end of each bubble discharging pipe 1 1 is connected to an air compressor through a pipe. In this way, small bubbles fed from the filter medium 3 side from the bubble discharging pipe 11 form many through holes leading to a filter medium 3 in a filter cake bed. Therefore, filtration is surely continued to adsorb filter cake thick.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vacuum dehydrator used for dehydrating water-containing substances such as sludge.

[0002]

2. Description of the Related Art Conventionally, for example, a filter drum having a cylindrical body covered with a filter medium and a large number of suction chambers partitioned from each other along the inner peripheral face of the filter medium are provided inside the filter drum. With the shaft supported horizontally, the lower half of the drum is immersed in the stock solution in the stock solution tank where sludge is injected, and the suction chamber is guided into the stock solution while depressurizing the inside according to the rotation of the filtration drum. The sludge is sucked in, while the moisture in the sludge is sucked in as a filtrate, while the solid content is captured as a sludge on the outer surface of the filter medium, and is successively deposited thickly, and then the suction chamber is continuously depressurized and discharged from the stock solution into the atmosphere. And sucking and dehydrating the water contained in the accumulated filter cake to form a dehydrated cake, then sending compressed air into the suction chamber to loosen the dehydrated cake from the outer surface of the filter medium, and then scraping the dehydrated cake from the surface of the filter medium. Peel off Vacuum cylindrical dehydrator are widely known.

[0003]

However, in the above conventional machine, when the sludge to be treated has a high viscosity or the solid content in the sludge is fine particles, in the sludge filtration step in the stock solution, The viscous filter cake forms a layer and sticks or adheres to the filter medium surface, and the fine particles of the filter cake closely adhere to each other to form a compacted filter cake layer on the filter medium surface, thereby closing the permeation holes of the filter medium and further filtering. Not only can the slag not be adsorbed thickly, but there is also the inconvenience that it cannot be dehydrated in the subsequent dehydration process in the atmosphere.

Further, when the sludge to be treated contains solids having a large specific gravity such as sand, such heavy solids are highly deposited on the bottom of the stock solution tank, and the deposited solids are generated when the filtration drum rotates. However, there is also a problem that the filter cake thickly adsorbed on the outer surface of the filter material is scraped off.

The first invention of the present application has an object to prevent the clogging of the filter medium even when the water-containing material to be treated has a high viscosity or contains a solid content of fine particles.

In addition to the problems of the first invention, the second invention of the present application has an object of eliminating the obstacle caused by the deposited solid matter when the sludge to be treated contains the solid matter having a large specific gravity.

[0007]

In order to solve the above problems, the first invention of the present application is such that a filter medium is located on the outer surface of a hollow body, and a suction chamber to be located inside the filter medium is provided inside the hollow body. In a vacuum dehydrator rotatably supported, such that the suction chamber is alternately introduced into the stock solution of the stock solution tank and into the atmosphere, in the stock solution tank, in the stock solution of the filtration hollow body. Providing a filter medium blockage prevention device in a vacuum dehydrator for hydrated substances, provided with a bubble discharger for continuously supplying a large number of small bubbles to the outer surface of the immersed filter medium,

The second invention of the present application, in place of the bubble ejector of the first invention, injects air toward the solid matter deposited on the inner bottom of the stock solution tank by using an air ejector, and produces small bubbles. The present invention proposes a device for preventing clogging of a filter medium in a vacuum dehydrator for a water-containing substance, which is provided in a positional relationship of supplying the above to the outer surface of the filter medium immersed in the stock solution.

The "filtering hollow body" in the present invention means a filter cylinder having an outer peripheral surface provided with a filter material and a plurality of suction chambers provided along the inner peripheral surface, along the inner peripheral surface. On the outer peripheral surface of the cylindrical body in which a plurality of suction chambers are arranged, an endless band-shaped filter medium is wound around the outer peripheral surface of the cylindrical body in a range of about 280 degrees, and a plurality of hollow disks are equidistantly arranged on the same axis. It includes a filter disk body in which a filter medium is attached to both sides of each hollow disk and a plurality of suction chambers are arranged in each disk, and various other structures. Further, as the above-mentioned "filter material", a filter cloth, a perforated plate, a filter membrane and various other materials are appropriately and selectively used. Further, as the above-mentioned "bubble discharger", there is one that sends high pressure air to a tubular body, a tubular body, a spherical body or the like made of porous porcelain ware, porous metal or the like to discharge bubbles. Embodiments of the present invention will be described below with reference to the drawings.

[0010]

EXAMPLE FIG. 1 shows an example of application to a vacuum cylinder type dehydrator, in which a filtering cylinder (1) is a hollow cylindrical body having a shaft (2) longitudinally secured to the center and a filter material made of a filter cloth on the outer peripheral surface. (3) is stretched, and a large number of suction small chambers (4) are arranged inside the filter medium (3) inside the hollow cylindrical body along the inner peripheral surface in an adjacent state, and each small chamber is arranged. The other end of the suction pipe (5), one end of which is connected to (4), is connected to the vacuum device and the compressor through the swivel joint fitted to the shaft (2). The body (1) is rotatably supported via the shaft (2) with its axis centered horizontally and with its lower half part immersed in the undiluted solution (7) in the undiluted solution tank (6). At the same time, the rotation of the motor can be transmitted to the shaft (2) through a pulley and a belt. (8) is a scraper whose tip is in contact with the outer surface of the filter medium (3) on one side of the filtration cylinder (1), and (9) is a stock solution tank (6)
A stock solution supply pipe into the inside, and (10) is a stirrer.

In the dehydrator as described above, a bubble discharge tube made of porous porcelain is provided on the lower left and right sides when viewed from the circular side surface of the lower surface of the filtration cylinder (1) immersed in the undiluted solution (7) in the undiluted solution tank (6). (11), (11) are arranged in parallel with the axis of the cylindrical body over the entire length of the cylindrical body (1) in the axial direction, and one end of each bubble discharge pipe (11), (11) is connected to the air compressor via the pipe. (Not shown).

The operation of the above example will now be described. As an example, sludge containing various organic fine particles such as soil and fiber is continuously supplied into the stock solution tank (6) from the stock solution supply pipe (9). The inside of each suction small chamber (4) is decompressed by rotating the filtration cylinder (1) and driving a vacuum device, and at the same time, air is pumped to the bubble discharge pipes (11) and (11) to discharge small bubbles. In the filtration step of moving in the undiluted solution (7), the sludge is sucked into the filter medium (3), the fine solid particles contained therein are adsorbed on the outer surface of the filter medium (3) as a filter residue, and water is passed through the filter medium (3). As a filtrate, inhale into the small chamber (4) ...
By continuing this, the filter cake layer (m) is deposited on the outer surface of the filter medium (3). On the other hand, the small bubbles discharged from the bubble discharge pipes (11) and (11) rise and are dispersed on almost the entire surface of the filter medium (3) in the undiluted solution and are sucked by the filter medium (3). Air bubbles are sucked while perforating the filter residue layer (m) to form a large number of through holes reaching the filter medium (3), and the small bubbles meander between the large and small solid matters in the filter residue. As shown in FIG. 2, the bent through holes (12) ... Once a through hole (1
2) ... Allows the small bubbles to be supplied thereafter to flow to maintain the through holes (12) ...
2) ... to suck new sludge to increase the buildup of slag, and continue this process.

Next, in a dehydration step in which the raw solution (7) is exposed to the atmosphere and moved to a position immediately before the scraper (8), the water contained in the filter cake layer (m) is passed through the through hole (1).
2) Inhale with the atmosphere through ... to form a dehydrated filter residue layer (m ').

Next, in the peeling step, compressed air is sent into the small chamber (4) to blow the air outward through the filter medium (3), whereby the outer surface of the filter medium (3) and the filter cake layer (m ') are discharged. The adhesion is loosened, and then the filter cake is peeled off as a cake with a scraper (8).

The vacuum cylindrical dehydrator of FIG. 3 is replaced with the bubble discharge pipes (11) and (11) in the dehydrator of FIG. 1 and has an air injection pipe (a plurality of air injection nozzles (13a) ... 11a) and (11a) at substantially the same positions as the bubble discharge pipes (11) and (11), and the injection nozzles (13a) ... (13a) ... to the substantially deepest bottom of the valley bottom of the stock solution tank (6a). While arranging in the state facing the bottom,
Except for the stirrer, the other structure is substantially the same as in FIG.
In this machine, as an example, sludge containing solid particles having a large specific gravity such as fine sand in addition to organic fine particles is continuously supplied into the stock solution tank (6a) through the stock solution supply pipe (9a). The solid matter having a large specific gravity such as fine sand in the supplied sludge is settled on the bottom of the tank (6a) and gradually thickened. When the filtering cylinder (1a) is rotated and the suction chambers (4a) are decompressed in the same manner as in FIG. 1 and air is jetted from the air jet nozzles (13a) ... at the same time, the filter medium (3a)
The solids are adsorbed on the outer surface of the filter medium (3a), while the air jetted from the nozzle diffuses the fine sand or the like that settles at the bottom while forming air bubbles.
a) The adsorption to the surface is promoted, and the particles are collided with the fine sand or the like to be subdivided into small bubbles and are dispersed and sucked over the entire surface of the filter medium (3a) in the undiluted solution, whereby as in the case of FIGS. A large number of holes communicating with the filter material (3a) are formed in the filter residue layer (ma) to prevent the filter material from being blocked, and the filter residue is deposited thickly.

[0016]

EFFECTS OF THE INVENTION According to the device for preventing clogging of the filter medium in the vacuum dehydrator for hydrated matter of the first aspect of the present invention, the hydrated matter to be treated has a high viscosity or contains solid matter of fine particles. Also, in the filtration in the undiluted solution, the small bubbles supplied from the bubble ejector to the filter medium can form a large number of through holes in the filter layer, which lead to the filter medium, thereby ensuring the continuous filtration. This can be achieved by thickly adsorbing the slag, and also in the dehydration in the atmosphere, sufficient dehydration can be performed from the through holes of the filter residue layer.

According to the device for preventing clogging of the filter medium in the vacuum dehydrator for hydrates of the second aspect of the present invention, the hydrates to be treated include solids having a high specific gravity, and these solids are highly deposited at the bottom of the stock solution tank. In addition, the air ejected from the air ejector can diffuse the deposited solid matter and promote adsorption to the filter medium, and the jetted air collides with the solid matter and is subdivided into small bubbles to supply the filter medium to the crucible. By doing so, the same effect as the first aspect of the invention can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a vacuum cylinder dehydrator in which a part of a filtration cylinder is cut away.

FIG. 2 is an enlarged cross-sectional view of a part of a filter cake layer.

FIG. 3 is a vertical sectional side view of another vacuum cylinder dehydrator in which a part of a filtration cylinder is cut away.

[Explanation of symbols]

 1, 1a Filter cylinder 3, 3a Filter medium 4, 4a Suction chamber 6, 6a Stock solution tank 7, 7a Sludge 11 Bubble discharge pipe 11a Air injection pipe 13a Air injection nozzle

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B01D 33/58 C02F 11/12 D

Claims (2)

[Claims] 1. A filtration hollow body comprising a hollow body and a suction medium to be located inside the filter medium, wherein the suction medium is located in the stock solution of a stock solution tank. In a vacuum dehydrator rotatably supported so as to be alternately guided to the atmosphere, a large number of small bubbles are continuously supplied to the outer surface of the filter medium immersed in the undiluted solution of the filtration hollow body in the undiluted solution tank. An apparatus for preventing blockage of a filter medium in a vacuum dehydrator for hydrated materials, which is provided with a power bubble discharger. 2. An air ejector in place of the bubble ejector,
2. The position relationship is provided in which the air is jetted toward the solid matter deposited on the inner bottom of the stock solution tank and the small bubbles generated by the jet are supplied to the outer surface of the filter medium immersed in the stock solution. A filter material blockage prevention device in a vacuum dehydrator for hydrated materials.