JPH11276819A - Filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the thickness of a precoat layer forming a filter column as uniform as possible and to reuse the precoating agent simply. SOLUTION: In a filter in which a filter column 2 which is formed from a casing of mesh structure and in which a precoat layer 21 comprising diatomaceous earth or the like is formed in advance is suspended/fitted from/to a partition wall 13 which partitions a cylindrical filter tank 1 into an upper part chamber 11 and a lower part chamber 12, the lower part of the tank 1 is formed to be a conical part 3 in which the inside diameter decreases downward, a filtrate supply pipe 4 is introduced from the side of the tank 1 to the inside, and the supply port 41 of the pipe 4 is opened toward the center of a tank formed in the conical part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filtration device provided with a precoat type filtration column used for precision filtration of a grinding fluid, a cutting fluid, etc., and more particularly to a filtration device capable of forming a uniform precoat layer. It relates to an improved structure of the device.

[0002]

2. Description of the Related Art Conventionally, as a filtering device for finely filtering a grinding fluid, a cutting fluid, etc., for example, as shown in FIG. 2, a cylindrical filtration tank 1 is partitioned into an upper chamber 11 and a lower chamber 12. A filtration column 2 made of a mesh-shaped casing is attached to the partition wall 13 in a hanging manner, and a precoat layer 21 on which diatomaceous earth or the like is deposited is formed on the surface of the filtration column 2, and the filtrate is applied to the precoat layer from the outside. A filtration device is used in a system that removes solids by passing through the filter 21.

In the case of this type of filtration device, forming a uniform precoat layer 21 on the outer surface of the filtration column 2 is an important matter from the viewpoint of maintaining high filtration performance. Then, the operation of forming the precoat layer 21 will be described with reference to FIG. 2. The filtrate mixed with the precoat agent is sent to the lower chamber 12 from the supply port 14 provided on the side wall of the filtration tank 1, and the filtrate is transferred to the upper chamber 11. At the time of permeation, the precoat agent is deposited on the casing surface of the filtration column 2 to form the precoat layer 21.

[0004] Since the precoat layer 21 is formed in this manner, the precoat layer near the supply port 14 for the precoat agent is formed thicker than the opposite side, and the thickness is partially uneven. Phenomenon was seen. In such a non-uniform precoat layer 21, since the function of capturing fine particles is lower in a thin portion than in a thick portion, the filtration accuracy is reduced as a whole. In addition, when a large amount of a precoat agent is supplied to increase the thickness of the entire precoat layer in order to increase the filtration accuracy, there is a problem that the filtration resistance increases and the filtration ability decreases.

In the above-mentioned filtration device, if the filtration operation proceeds and a large amount of captured solids accumulates on the precoat layer to cause clogging, the filtration resistance increases abnormally and the filtration efficiency decreases. An operation for removing such deposits is performed. That is, the precoat layer is dropped from the filtration column together with the captured solids by stopping the pressurization of the filtrate or further applying a reverse pressure. Thereafter, a new precoat layer may be formed again by the above-described method.

In this case, in order to reuse the dropped pre-coating agent, the pre-coating agent is withdrawn from the outlet at the lower end of the lower chamber 12 of the filtration tank 1, temporarily stored, and then renewed from the supply port 14. It was necessary to perform the above-mentioned method of supplying and attaching together with the filtrate.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a filtration apparatus capable of making the thickness of a precoat layer formed on a filtration column as uniform as possible. provide. Further, the present invention provides a filtration device which can be easily reused without the necessity of extracting the precoat agent from the filtration tank when the precoat layer is once disassembled and reused again during the filtration operation.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems. The present invention provides a filtration apparatus in which a filtration column on which a precoat layer can be formed is disposed in a cylindrical filtration tank. The lower part of the filtration tank is a conical portion that is reduced in diameter downward, a filtrate supply pipe is introduced into the filtration tank, and the supply port is opened from above toward substantially the center of the conical part. It is characterized by having. Further, the present invention can be preferably embodied as a filtration device having an opening angle of 60 to 90 degrees toward the upper side of the conical portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to FIG. In FIG. 1, the filtration device of the present invention is a filtration device in which a filtration column 2 on which a precoat layer can be formed is disposed in a cylindrical filtration tank 1. A filtration column 2 composed of a mesh-structured casing is attached to a partition 13 that partitions the chamber 11 and the lower chamber 12 from the casing 13. In this case, the number of filtration columns is two, but the required number can be appropriately selected according to the intended filtration capacity and the like.

A precoat layer 21 made of diatomaceous earth or the like is formed on the surface of the filtration column 2 in advance, and a filtration operation is performed by allowing the filtrate to pass through the precoat layer 21 from the outside. In such a structure,
There is no particular difference from the conventional one.

A feature of the present invention is that a lower portion of the filtration tank 1 is formed in a conical portion 3 whose inner diameter decreases downward, and a filtrate supply pipe 4 is provided in the filtration tank 1. The point is that the supply port 41 is introduced into the tank from the side, and the supply port 41 is opened from above toward substantially the center of the conical portion 3.

Next, the operation of this filtration apparatus will be described. First, in order to perform pre-coating, a predetermined amount of pre-coating agent (mainly diatomaceous earth powder) is placed in a mixing tank 7 in which a filtrate is stored in advance. Use) and pump 6
Is operated to supply the precoat agent to the filtration tank 1 via the filtrate supply pipe 4 together with the filtrate.

Here, the mixed filtrate flows from the lower chamber 12 through the filtration column 2 to the upper chamber 11, and the upper outlet 1
The mixture is refluxed from the four-way valve 61 to the mixing tank 7 through the three-way valve 61. At this time, the precoat agent is deposited on the outer surface of the filtration column 2. In this case, the precoat layer 21 having a predetermined thickness is formed. The mixed filtrate may be circulated until the mixture is discharged.

In this case, the filtrate containing the precoating agent is discharged from the supply port 41 of the filtrate supply pipe 4 toward substantially the center of the conical portion 3 at the lower portion of the filtration tank 1, and its water flow is reduced. , And are wound up and reach the upper filtration column 2 under stirring, so that the advantage that the precoat layer 21 of each filtration column 2 is formed evenly is obtained. In addition, as the filtration column 2, a cylindrical casing made of a wire mesh having a predetermined mesh or a normal filtration column in which a filtering material such as a nonwoven fabric is formed into a cylindrical shape can be applied.

Next, in order to carry out the filtration operation, the three-way valve 61 is switched so that the filtrate is sent to the filtrate tank 8 and the supply of the filtrate from the mixing tank 7 is continued. When the filtration operation proceeds and clogging or the like occurs, the clogging is eliminated by the following operation, a precoat layer is formed again, and the operation is restarted.

First, the operation of the pump 6 is stopped, the filtration pressure on the filtration column is released, and the precoat layer 21 is disassembled and dropped by its own weight. Further, if necessary, the precoat layer 21 can be peeled off by a reverse pressure such as applying a pressure from the inside of the filtration column 2. Thus,
The precoat layer will stay in the collapsed state at the bottom of the conical section 3.

Here, when the three-way valve 61 is switched to the precoat line A side and the operation of the pump 6 is resumed, the filtrate water flow discharged from the supply port 41 of the filtrate supply pipe 4 is retained. As it collides with the precoat agent and is wound up while being dispersed in all directions, and reaches the upper filtration column 2 in a stirring state, each filtration column is formed in the same manner as in the first precoat layer forming operation. Since the second precoat layer 21 is formed evenly, the filtration operation can be restarted. When the remaining precoat agent is extremely dirty, it cannot be reused. Therefore, the discharge valve 5 at the bottom of the conical portion 3 is opened, and the precoat agent is taken out together with the filtrate and discarded.

As described above, according to the present invention, even when the precoat layer is formed first, and also in the formation of the precoat layer after measures against clogging, the thickness unevenness of each filtration column is significantly improved. It has been found that the filtration accuracy can be greatly improved, for example, when the removal rate of particles having a particle diameter of 1 μm is about 90% in the conventional case, this can be improved to 100%.

In the present invention, it is preferable to embody the filtering device in a form in which the opening angle of the conical portion upward is 60 to 90 degrees. This opening angle is 90
Exceeding the degree, the effect of entrainment of the precoat agent by the rising filtrate water flow discharged from the supply port 41 becomes insufficient.
If the angle is smaller than 60 degrees, the vertical length of the conical portion becomes too large, which is not preferable.

[0020]

As described above, the filtration device of the present invention is configured as described above, so that the thickness of the precoat layer on the filtration column can be made uniform when formed, and as a result, the filtration accuracy is greatly improved. I was able to. In addition, when the precoat layer is disassembled during the filtration operation and reused again, the precoat agent does not need to be extracted from the filtration tank and can be easily reused, so that the operability of the filtration device is improved. Has an excellent effect. Therefore, the present invention has a very large industrial value as a filtration device which has solved the conventional problems.

[Brief description of the drawings]

FIG. 1 is a conceptual cross-sectional view for explaining a filtration device of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part of a conventional filtration device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Filtration tank, 11 upper chamber, 12 lower chamber, 13 partition, 2 filtration column, 21 precoat layer, 3 conical part, 4 filtrate supply pipe, 41 supply port.

Claims (2)

[Claims] 1. A filter device comprising a cylindrical filtration tank provided with a filtration column on which a precoat layer can be formed, wherein a lower portion of the filtration tank is formed as a conical portion having a diameter reduced downward, and a filtrate is supplied. A filter device, wherein a pipe is introduced into the filtration tank, and a supply port thereof is opened from above toward substantially the center of the conical portion. 2. The filtering device according to claim 1, wherein an upward opening angle of the conical portion is 60 to 90 degrees.