JP2701198B2 - Filter media blockage prevention device for vacuum dehydrator of hydrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, for example, a filter drum in which a filter medium is provided on an outer peripheral surface of a cylindrical body and a number of suction chambers partitioned from each other along the inner peripheral surface inside the filter medium is provided. With the shaft supported horizontally, the lower half of the drum is immersed in the stock solution of the stock tank into which the sludge is injected, and as the filter drum rotates, the suction chamber is guided into the stock solution while depressurizing the inside. The sludge is sucked, the water in the sludge is sucked in as a filtrate, and the solid content is captured as a filter cake on the outer surface of the filter material, and is successively thickly deposited. And, to make a dehydrated cake by sucking and dewatering the water contained in the sediment cake, then send compressed air into the suction chamber to loosen the dewatered cake from the outer surface of the filter medium, and then scrape the dehydrated cake from the filter medium surface with a scraper. Peel off Vacuum cylindrical dehydrator are widely known.

[0003]

However, in the above-mentioned conventional apparatus, when the sludge to be treated has a high viscosity or when the solid content contained in the sludge is fine particles, the sludge filtration step in the undiluted solution is difficult. The viscous filter cake forms a layer and sticks or adheres to the filter media surface, and the fine particles of the filter cake closely adhere to each other to create a compact filter cake layer on the filter media surface, thereby closing the permeation holes of the filter media and further filtering. In addition to being unable to adsorb the slag thickly, there is a disadvantage that the dewatering cannot be performed in the next dehydration step in the atmosphere.

When the sludge to be treated contains solids having a large specific gravity, such as sand, such heavy solids are deposited high 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 medium is scraped off.

It is an object of the first invention of the present application to prevent a filter medium from being clogged even when a hydrate to be treated has a high viscosity or contains a solid content of fine particles.

A second object of the present invention is, in addition to the object of the first aspect, to solve the problem caused by solid deposits when sludge to be treated contains solids having a high specific gravity.

[0007]

In order to solve the above-mentioned problems, a first invention of the present application is to dispose a filter medium on an outer surface of a hollow body and arrange a suction chamber inside the hollow body inside the filter medium. In the vacuum dehydrator rotatably supported so that the suction chamber is alternately guided into the undiluted solution in the undiluted solution tank and into the atmosphere, the undiluted solution in the undiluted solution in the undiluted solution tank, Providing a filter medium blockage prevention device in a vacuum dehydrator for hydrates, provided with a bubble ejector to continuously supply many small bubbles to the outer surface of the immersed filter medium,

[0008] The second invention of the present application is directed to a small-bubble generated by the injection by injecting air toward a solid substance deposited on the bottom of the stock tank, instead of the bubble discharger in the first invention. The present invention proposes an apparatus for preventing filter material blockage in a vacuum dehydrator for hydrates, which is provided in a positional relationship of supplying the filter medium to the outer surface of a filter medium immersed in the stock solution.

In the present invention, the term "filtration hollow body" refers to a filtration cylindrical body in which a filter medium is stretched on the outer peripheral surface, and a plurality of suction chambers are arranged inside the inner peripheral surface, and along the inner peripheral surface. A filter cylinder in which an endless band-shaped filter medium is wrapped around the outer peripheral surface of the cylindrical body in a range of about 280 degrees on the outer peripheral surface of the cylindrical body provided with a plurality of suction chambers, and a plurality of hollow disks are equally spaced on the same axis. It includes a filter disk having a filter medium attached on both sides of each hollow disk and having a plurality of suction chambers disposed in each disk, and various other structures. As the above-mentioned "filter medium", a filter cloth, a perforated plate, a filtration membrane and other various materials are appropriately and selectively used. Further, as the above-mentioned "bubble emitter", there is a device that blows high-pressure air into a tubular body, a tubular body, a spherical body, or the like made of porous ceramics, porous metal, or the like to release bubbles. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0010]

FIG. 1 shows an embodiment in which the present invention is applied to a vacuum cylindrical dehydrator. The filter cylinder (1) has a filter medium made of filter cloth on the outer peripheral surface of a hollow cylinder having a shaft (2) fixed vertically through the center. (3) is stretched, and a number of small suction chambers (4) are arranged annularly along the inner peripheral surface inside the hollow cylindrical body inside the filter medium (3). The other ends of the suction pipes (5) having one end connected to (4) are connected to a vacuum device and a compressor via a swivel joint fitted on the shaft (2). The body (1) is rotatably supported via the shaft (2) with its axis centered horizontally and with its lower half immersed in the stock solution (7) in the stock solution tank (6). At the same time, the rotation of the motor can be transmitted to the shaft (2) via a pulley and a belt. (8) is a scraper whose one end 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, (10) is a stirrer.

In the dehydrator as described above, a bubble discharge pipe made of porous ceramics is provided at the lower right and left sides of the lower surface of the filter cylinder (1) immersed in the stock solution (7) in the stock solution tank (6). (11) and (11) are disposed 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 of the bubble discharge pipes (11) and (11) is connected to the air compressor through the pipe. (Not shown).

The operation of the above example will now be described. As an example, sludge containing various kinds of organic fine particles such as soil, fiber and the like is continuously supplied from a stock solution supply pipe (9) into a stock solution tank (6). By rotating the filtration cylinder (1) and depressurizing the inside of each suction chamber (4) by driving the vacuum device, air is also fed to the bubble discharge tubes (11) and (11) to discharge small bubbles. In the filtration step moving through the stock solution (7), the sludge is sucked into the filter medium (3), fine solids contained therein are adsorbed as filter cake on the outer surface of the filter medium (3), and moisture is passed through the filter medium (3). Inhaled into the small chamber (4) as the filtrate,
This is continued to deposit a filter cake layer (m) on the outer surface of the filter medium (3). On the other hand, the small bubbles released from the bubble discharge tubes (11) and (11) rise and disperse over almost the entire surface of the filter medium (3) in the undiluted solution and are sucked by the filter medium (3). The air bubbles are sucked while forming a large number of through holes that reach the filter medium (3) by piercing the filter cake layer (m), and the small bubbles meander between large and small solids in the filter cake. 2 to form bent holes (12), which are irregularly branched, as shown in FIG. Once drilled through holes (1
In 2), small bubbles supplied thereafter are allowed to flow to maintain the through holes (12).
2) Suction of new sludge through... To increase the amount of cake, and this will be continued thereafter.

Next, in the dehydration step of exposing from the stock solution (7) to the atmosphere and moving to a position just before the scraper (8), the water contained in the filter cake layer (m) is removed from the through-hole (1).
2) Inhaled together with the air through ... to form a dehydrated cake layer (m ').

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

The vacuum cylindrical dehydrator of FIG. 3 has a plurality of air injection nozzles (13a) as air injectors instead of the bubble discharge tubes (11) and (11) of the dehydrator of FIG. 11a) and (11a) are located at substantially the same positions as the bubble discharge tubes (11) and (11), and each of the injection nozzles (13a)... (13a). Along with disposing it toward the bottom,
Except for the stirrer, other structures are substantially the same as in FIG.
In this machine, as an example, sludge containing solid matter having a large specific gravity such as fine sand in addition to organic fine particles is continuously supplied into a stock solution tank (6a) via a stock solution supply pipe (9a). Solid matter having a large specific gravity, such as fine sand, in the supplied sludge precipitates at the bottom of the tank (6a) and gradually thickens. When the filter cylinder (1a) is rotated and the suction chambers (4a) are depressurized in the same manner as in FIG. 1 and air is jetted from the air jet nozzles (13a) together with the filter medium (3a).
The solid matter is adsorbed on the outer surface of the filter medium (3a), while the air jetted from the nozzle diffuses fine sand and the like settled at the bottom while forming bubbles, and the air is injected from the nozzle.
a) While adsorbing on the surface, it collides with the fine sand or the like and is finely divided into small bubbles while being dispersed and sucked over the entire surface of the filter medium (3a) in the undiluted solution. A large number of through holes are formed in the filter cake layer (ma) to communicate with the filter medium (3a) to prevent the filter medium from being clogged, and to deposit the filter cake thickly.

[0016]

According to the apparatus for preventing clogging of the filter medium in the hydrated vacuum dewatering machine of the first invention of the present application, the hydrated substance to be treated has a high viscosity or contains fine solid particles. However, in the filtration of the undiluted solution, the small bubbles supplied to the filter medium from the bubble discharger can form a large number of holes in the filter cake layer that lead to the filter medium, thereby ensuring that the filtration is continuously performed. Thickness of the residue can be absorbed, and sufficient dehydration can be performed from the through-holes of the filter cake layer even in dehydration in the atmosphere.

According to the apparatus for preventing clogging of a filter medium in a vacuum dehydrator for hydrated materials according to the second aspect of the present invention, the hydrated material to be treated includes solids having a high specific gravity, and these solids are deposited on the bottom of the stock solution tank at a high level. In addition, the air injected from the air injector diffuses the deposited solids to promote adsorption to the filter medium, and the injected air collides with the solids to be subdivided into small bubbles and the filter medium is supplied to the alligator. By doing so, the same effect as the first invention can be obtained.

[Brief description of the drawings]

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Filtration cylindrical body 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

Claims (2)

(57) [Claims] 1. A filter hollow body having a filter medium located on the outer surface of a hollow body and a suction chamber to be located inside the filter medium inside the hollow body, wherein the suction chamber is provided in a stock solution in a stock solution tank and In a vacuum dehydrator rotatably supported so as to be alternately guided into the atmosphere, a large number of small bubbles are continuously supplied to the outer surface of a filter medium immersed in the undiluted solution of the filtration hollow body in the undiluted solution tank. A device for preventing filter material from being clogged in a vacuum dehydrator for hydrates, which is provided with a bubble discharger. 2. An air injector, in place of the above-mentioned bubble ejector,
2. The positional relationship according to claim 1, wherein air is jetted toward solids deposited on the bottom of the stock tank, and small bubbles generated by the jet are supplied to an outer surface of a filter medium immersed in the stock solution. 3. Filter media blockage prevention device in vacuum dehydrator for hydrated material.