JP2001054705A - Method and device for filtering - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter device capable of eliminating a filter plate and to uniformly attain decreasing of water content of a cake. SOLUTION: In the filtering method, when gas is filtered by making the gas pass through a filter implement 13 in which the material to be filtered is filled between two sheets of filter fabric. Two pairs of the filter implements 13 and 13 are arranged so that the filter fabrics contact each other, and the gas passes from the filter fabric in non-contact state of the filter implement 13 to the filter fabric in contact state in an arrow F direction, then the gas passes through the filter fabrics in contact state and discharged. In such a way, The gas is filtered while making the filters vibrate in contact state.

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 filtration method and a filtration device.

[0002]

2. Description of the Related Art In order to reduce the water content of a cake obtained by filtration, a filter tool filled with an object to be filtered between two filter cloths and a filter cloth from one filter cloth to another filter cloth are used. There is a method in which a gas is passed through and filtered.

[0003] Filtration devices suitable for this filtration method include:
There is one described in JP-A-6-312106. As shown in FIG. 5, the filtering device 1 includes a container 2 in which left and right headers 2a, 2a and an appropriate number of filter plates 2b are separable and connectable, and internal spaces A formed inside the container 2. Filter cloths 3 and 3 for dividing the filter cloth into an inflow section A-1 and an outflow section A-2, and a filter communicating with a filling section A-3 formed between the two filter cloths 3 and 3. A stock solution supply passage 4, an air supply passage 5 communicating with the inflow portion A-1, and an outflow portion A-2.
And a discharge passage 6 communicating with the discharge passage. Filtration solution supply path 4
Has an inflow end connected to a filtered undiluted solution storage tank (not shown) to receive the undiluted filtered solution from the undiluted filtration solution storage tank.

When the undiluted filtrate is press-fitted into the filling section A-3 from the undiluted solution supply line 4, the filtrate having passed through the filter cloths 3 and 3 is discharged from the discharge line 6 to the outside of the device and filtered. I do. When a predetermined amount of cake K is filled in the filling section A-3, the filtration device 1 stops press-in of the undiluted filtration solution, and then presses gas from the gas supply path 5 into the inflow section A-1. The pressurized gas passes through the filter cloth 3, the cake K, and the filter cloth 3 in one direction, and is discharged to the outside of the apparatus via the outlet A-2 and the discharge path 6. The gas passing through the cake K lowers the water content of the cake K.

[0005]

The filtering device 1 has a filter plate 2b for forming a plurality of internal spaces A in the container 2. The filter plate 2b is formed of a thick plate that can withstand the pressure of the undiluted filtrate and gas.
However, the filter plate 2b having a large plate thickness becomes heavy, which causes a problem that the manufacturing cost is increased and the operability of the filter device 1 is deteriorated.

[0006] Further, once a passage is formed in the cake K, the gas passing through the cake K does not pass through another portion. Therefore, the filtration device 1 may cause a problem that the water content of the cake K is not uniformly reduced.

Accordingly, an object of the present invention is to provide a filtration device capable of omitting a filter plate, a filtration method and a filtration device capable of uniformly lowering the water content of a cake in order to solve the above problems. And

[0008]

In order to reduce the water content of the cake uniformly, the means adopted by the present invention according to the first aspect of the present invention is to remove the material to be filtered between two filter cloths. In a filtration method in which a gas is passed through a filled filter to perform filtration, two sets of filter tools are arranged so that filter cloths are in contact with each other, and the filter cloth of each set of filter tools without contact is used to remove the contact. This is a filtration method characterized in that after passing a gas toward a certain filter cloth, the gas is passed through and discharged between the filter cloths in contact with each other, whereby the filter cloths in contact with each other are filtered while vibrating. In the present invention, the two sets of filter tools are pressed against the filter cloths that come into contact with the gas, so that the filter cloths that come into contact with each other are in close contact over the entire contact surface. Therefore, the gas that tries to pass between the filter cloths
The passage is not stable at a certain point and changes every moment, causing the filter cloths in contact with each other to vibrate. As a result, the gas passing through the material to be filtered, which is filled in the filtering tool, passes through the passage so that the passage is not stable at a certain place, and changes every moment, and is dispersed throughout the material to be caked. Thus, the water content can be reduced uniformly over the entire cake.

The means adopted by the present invention according to claim 2 to promote the reduction of the water content of the cake is the filtration method according to claim 1, wherein a gas having a reduced relative humidity is used as the gas. The relative humidity may be reduced by heating or dehumidifying the gas. In the present invention, since the gas passing through the material to be filtered has a low relative humidity, it is possible to promote a uniform decrease in the water content over the entire cake.

In order to make it possible to omit the filter plate and to uniformly reduce the water content of the cake, the means adopted by the present invention according to claim 3 is to reduce the internal space of the container, In a filtering device partitioned into a plurality of partitions with a plurality of sets of filter tools having a filling portion formed between two filter cloths, two sets of filter tools adjacent to each other can be brought into contact with each other. A filtering device, wherein a discharge path is communicated with partitions that are arranged and the filter cloths facing each other face each other, and an air supply path is communicated with each partition that faces the filter cloths that do not face each other.
In the present invention, when the pressurized gas is supplied to the air supply path in a state where the objects to be filtered are filled in the two sets of filter tools, the filter cloths facing each other of the two sets of filter tools are brought into close contact with each other. The gas passes from the non-contact filter cloth of each set of filter tools toward the contact filter cloth, passes between the contact filter cloths, is guided to the discharge path, and is exhausted to the outside. . And the gas that is going to pass between the filter cloths that are in close contact with each other is not stable at a certain location, and will change every moment.
Vibrating the filter cloths in contact with each other. As a result, the gas passing through the material to be filtered, which is filled in the filtering tool, passes through the passage so that the passage is not stable at a certain place, and changes every moment, and is dispersed throughout the material to be caked. Thus, the water content can be reduced uniformly over the entire cake.

In order for the water content of the cake to be reduced more evenly, the means adopted by the present invention according to the fourth aspect of the present invention is to provide an inner space of the container and a filling portion between the two filter cloths. In a filtering device partitioned into a plurality of partitions by an even number of sets of filter tools to be formed, adjacent filter tools are arranged so that the facing filter cloths can come into contact with each other, and a partition section at one end and a partition section at the other end. The odd-numbered partitioning portions counted toward one another are communicated through one passage, the even-numbered partitioning portions are communicated through the other passageway, and both passages are connected to the alternate supply / exhaust device. Is a filter device, wherein when one of the passages is in an air supply state, the other passage is in an exhaust state, and when the other passage is in an air supply state, one of the passages is in an exhaust state. It is. In the present invention, two sets of adjacent filter tools have the same effect as the invention of claim 2, and can alternately change the traveling direction of the gas passing through the cake generated in the filling portion,
By alternately changing the direction of the gas passing through each filter cloth, the moisture content in the cake can be made more uniform and clogging of the filter cloth can be prevented.

In order to promote uniform reduction of the water content of the cake, the means adopted by the present invention according to the fifth aspect is provided with a relative humidity reducing device for reducing the relative humidity of the gas supplied to the supply passage. The filtration device according to claim 3 or 4. As this relative humidity reduction device, there is a device that heats the outside air that becomes a gas to be supplied to the supply passage, or a device that dehumidifies the outside air. In the present invention, the gas whose relative humidity has been reduced by the relative humidity reduction device is allowed to pass through the material to be filtered filled in the filter, thereby promoting a uniform reduction in the water content throughout the cake. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a filtration method and a filtration apparatus according to the present invention will be described with reference to the embodiments shown in FIGS. 1 is a cross-sectional view showing a state before filtration, FIG. 2 is a cross-sectional view showing a state in the middle of filtration, FIG. 3 is a cross-sectional view showing a state in which cake is discharged, and FIG. It is.

As shown in FIG. 1, a filtration device 11 of the present embodiment comprises a container 12 for joining even numbers of four sets of filter tools 13 by pressing them with headers 14 and 15 at both front and rear ends, A path 17 and a supply / exhaust path 18 are provided. Container 1
2 is a set of four filters 13 and headers 14, 14 at the front and rear ends.
5 can be joined and separated, and when they are joined, the internal space is partitioned into five partitioning parts 23 by four sets of filtering tools 13. The five partitions 23 communicate with the supply / exhaust passage 18 to supply or discharge gas. The container 12 is provided with four sets of filter tools 13 and headers 14 and 15 at both front and rear when discharging a cake K (see FIG. 3) described later or performing maintenance and inspection.
And are separated.

The filter device 13 of each set includes a flexible filter cloth 21 having a peripheral portion attached to a frame 19 and a flexible filter cloth 21 having a peripheral portion attached to a frame 20. The two frames 19 and 20 can be joined and separated. Each set of the filter 13 is provided with a part 17 a of the undiluted liquid supply path 17 and a part 18 e of the supply / exhaust path 18. Filter set 1 for each set
3 is a filling section 2 for filling the undiluted solution between the two filter cloths 21 and 21 when the two frame bodies 19 and 20 are joined.
2, the cake K can be discharged from between the filter cloths 21 and 21 when the frames 19 and 20 are separated (see FIG. 3). The filling section 22 is formed between the partition sections 23, 23 and communicates with the undiluted filtrate supply path 17. In each set of filter tools 13, the adjacent filter tools 13 and the opposing filter cloths 21 and 21 can be brought into contact with each other when filtering (see FIG. 2).

The undiluted filtration solution supply path 17 supplies undiluted filtration solution sent from an undiluted filtration solution supply device 24 comprising an undiluted solution tank and a pump to the filling units 22 of the four sets of filtration tools 13. . In addition, the filtration stock solution supply path 17
In some cases, gas is mixed as fine bubbles into the undiluted filtration solution to improve the flowability of the undiluted filtration solution and supply it to each filling unit 22. The undiluted solution supply passage 17 is provided with four sets
In order for this to move, an appropriate place is formed by the flexible pipe 17b. The filtration solution supply path 17 is provided with an on-off valve 17c for preventing backflow.

The supply / exhaust passage 18 communicates, through one passage 18a, between odd-numbered partitions 23 counted from one end to the other end of the five partitions 23 formed inside the container 12. At the same time, the even-numbered partition portions 23 communicate with each other through the other passage 18b, and both the passages 18a, 18a
8b is connected to the alternate air supply / exhaust device 25. Both passages 18a and 18b are formed by flexible pipes 18c in place for the four sets of the filter tools 13 to move. The alternate air supply / exhaust device 25 includes an air supply device 26 including a compressor or a blower, a relative humidity reduction device 29 provided on the upstream or downstream side of the air supply device 26, the air supply / exhaust passage 18 and the air supply device 2.
And a switching valve 27 joined to the switching valve 6. Air supply device 26
Is designed to take in outside air as a gas or to take in an inert gas such as nitrogen gas from a gas generator (not shown) or a gas cylinder. The relative humidity reducing device 29 is provided as needed, and a heating device or a dehumidifying device is selected so as to reduce the relative humidity of the gas supplied through the air supply device 26. The switching valve 27 is composed of a solenoid valve or the like. When one of the passages 18a is in the air supply state, the other passage 18b is in the exhaust state, and when the other passage 18b is in the air supply state, the one of the passages 18a is exhausted. The air supply state and the exhaust state can be alternately repeated. The supply / exhaust passage 18 includes drain passages 18d for discharging a filtrate generated during the filtration.
They are joined via an on-off valve 28. When the filtrate can be discharged through the switching valve 27, the drain path 18d,
18d can be omitted. The alternate supply / exhaust device 25 may be configured to circulate the gas to be supplied / exhausted while dehumidifying by the relative humidity reduction device 29.

Although not shown, the filtration device 11 does not use the supply / exhaust passage 18 as a drain passage.
In addition to the supply / exhaust passage 18, a drain passage with an on-off valve communicating with each partition 23 may be provided.

Next, a filtering method using the filtering device 11 will be described in accordance with the operation procedure. First, as shown in FIG. 1, the filtering device 11 forms a container 12 by tightly joining four sets of filtering tools 13 and headers 14 and 15 at both front and rear ends. Next, as shown in FIG. 2, the filtration device 11 pressure-feeds the filtrate through the undiluted solution supply path 17 to the filling portion 22 of each set of the filter 13. The pumped undiluted filtrate is separated into a filtrate passing through the filter cloths 21 and 21 of each set of the filter tools 13 and a cake K remaining in the filling section 22.
The filtrate passes through one of the supply / exhaust passages 18a and is discharged to the outside. When bubbles are mixed in the filtrate sent to the filling section 22, gas in the bubbles passes through the filter cloths 21 and 21 together with the filtrate, so that clogging of the filter cloths 21 and 21 is prevented. .

When the cake K, which is the material to be filtered, is filled in each of the filling portions 22, the filter device 11 closes the on-off valve 17c of the undiluted filtrate supply passage 17 to stop press-in of the undiluted filtrate. The alternate air supply / exhaust device 25 is started. In the alternate supply / exhaust device 25, the switching valve 27 is periodically switched by a solenoid or the like, and when the other passage 18b of the supply / exhaust passage 18 is supplying air, one supply / exhaust state (FIG. (See arrow F in the middle) and one of the passages 18a
When the air is supplied to the other passage, the other supply / discharge state of exhausting the other passage 18b (the direction opposite to the arrow F direction in the figure) is alternately repeated.

As shown in FIG. 2, the filter device 11 supplies the pressurized gas from the other passage 18b of the supply / exhaust passage 18 in a state where the cake K is filled in two adjacent sets of the filter tools 13, 13. Then, the filter cloths 21 and 21 facing the two sets of filter tools 13 and 13 come into close contact with each other, and the filter cloth 21 with no contact of the filter cloths 21 of each set and the filter cloths 2 with the contact are removed.
1, the gas passes in the direction of arrow F, and passes between the filter cloths that come into contact with the gas.
It is led to a and exhausted to the outside. Then, the gas that is going to pass between the filter cloths 21 and 21 that are in close contact with each other is not stable at a certain location, and changes every moment, causing the filter cloths 21 and 21 in contact with each other to vibrate. . As a result, the gas passing through the cake K filled in each of the filter tools 13 passes such that its passage is not stable at a certain place, changes every moment, and is dispersed throughout the cake K.
The moisture content of the cake K is uniformly reduced throughout. Even when the pressurized gas is supplied to one of the passages 18a of the supply / exhaust passage 18, the filter cloths 21 and 21 that come into contact with each other in the same manner as described above are vibrated with respect to the two sets of filter tools 13 in the center of FIG. The water content of the cake K will be reduced uniformly.

The cake K of each set of filters 13 has a uniform water content because the traveling direction of the passing gas (generally using air) is alternately and repeatedly changed. The gas passing while vibrating the filter cloths 21 and 21 in contact with each other prevents clogging of each filter cloth 21 and improves the separation between each filter cloth 21 and the cake K. In addition, when a gas whose relative humidity is reduced by the relative humidity reducing device is used, it is possible to promote a uniform decrease in the water content over the entire cake.

Finally, when the water content in the cake K drops to a predetermined rate, the filtering device 11 stops the alternate air supply / exhaust device 25 as shown in FIG. The frames 19 and 20 in the state are separated, the filling portions 23 are opened, the cake K is discharged, and one cycle of the filtering operation is completed.

The filtering device 11 does not include the alternate air supply / exhaust device 25 and is provided with one of the passages 18 of the air supply / exhaust passage 18.
It is also possible to reduce the water content of the cake K of each filter 13 while keeping a in the exhausted state and keeping the other passage 18b in the supplied state. Further, as shown in FIG. 4, the filtering device 11 can be composed of two sets of filtering tools 13. The filtering device 11 divides the internal space of the container 12 into three partitions 23 by two sets of filtering tools 13, 13, and makes the two sets of filtering tools 13, 13 facing each other contact the filter cloths 21, 21. The discharge passage 29 communicates with the partition 23 facing the filter cloths 21 and 21 facing each other, and the air supply path 30 communicates with each partition 23 facing the filter cloth 21 without the confrontation. I have. The air supply path 30 is provided with a drain path 31 with an on-off valve for discharging the filtrate during filtration.
As a device for supplying gas to the air supply passage 30, a device provided with the air supply device 26 and the relative humidity reduction device 29 shown in FIG.

When the pressurized gas is supplied to the air supply passage 30 in a state where the cake K, which is an object to be filtered, is filled in the two adjacent filter tools 13, 13, the two filter tools 13, 13 face each other. The filter cloths 21 and 21 are brought into close contact with each other, and gas passes in the direction of arrow F from the non-contact filter cloth 21 of each set of the filter tools 13 toward the contact filter cloth 21, and the filter cloth 13 contacts the filter cloth 13. Through the filter cloth to the discharge path 29,
It is exhausted to the outside. Then, the gas that is going to pass between the filter cloths 21 and 21 that are in close contact with each other is not stable at a certain location, and changes every moment, causing the filter cloths 21 and 21 in contact with each other to vibrate. . As a result, the gas passing through the cake K filled in each of the filter tools 13 passes such that its passage is not stable at a certain place, changes every moment, and is dispersed throughout the cake K. The water content of the cake K will be reduced uniformly. When a gas having a reduced relative humidity is used, a uniform decrease in the water content of the cake K can be promoted.

[0026]

According to the filtering method and the filtering apparatus according to the present invention, gas is passed so as to be dispersed throughout the material to be filtered (cake) by vibrating the filter cloths in contact with each other. As a result, the water content of the material to be filtered can be reduced uniformly. In the filter device according to the third and fourth aspects of the present invention, a filter plate which has been conventionally required is not present between adjacent filter tools, so that manufacturing cost is reduced and operability is improved by weight reduction. Can be planned. Since the direction of gas passing through each filter cloth can be alternately changed, the water content in the cake can be made more uniform, and clogging of the filter cloth can be prevented. The filtering method and the filtering device according to the present invention described in claim 5 can promote uniform reduction in the water content of the cake by using a gas having a reduced relative humidity.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a filtration method and a filtration device according to the present invention, and is a cross-sectional view showing a state before filtration.

FIG. 2 is a cross-sectional view showing a state during the filtration in the embodiment.

FIG. 3 is a cross-sectional view showing a state of cake discharge in the embodiment.

FIG. 4 is a cross-sectional view showing another aspect and showing a state before filtration.

FIG. 5 is an enlarged cross-sectional view of a main part of a conventional filtration device, showing a state in which gas passes through a cake.

[Explanation of symbols]

 13: Filtering tool, 21: Filter cloth, 29: Relative humidity reduction device

Claims (5)

[Claims] 1. A method of filtering by passing a gas through a filter tool filled with an object to be filtered between two filter cloths, wherein two sets of filter tools are arranged so that the filter cloths are in contact with each other. After passing gas from the non-contact filter cloth of each set of filter tools toward the contact filter cloth, the gas is passed through and discharged between the contact filter cloths, so that the filter cloths in contact with each other are discharged. Filtration while vibrating the filter. 2. The method according to claim 1, wherein said gas is a gas having a reduced relative humidity. 3. A filter device in which an inner space of a container is divided into a plurality of partitions by a plurality of sets of filter tools having a filling portion formed between two filter cloths. The filter cloths facing each other are arranged so as to be in contact with each other, the discharge path is communicated with the partition part facing the filter cloths facing each other, and the air supply path is communicated with each partition part facing the filter cloth not facing the filter cloth. A filtering device, characterized in that: 4. A filter device in which an inner space of a container is divided into a plurality of partitions by an even number of sets of filter tools forming a filling portion between two filter cloths, and adjacent filter tools face each other. Filter cloths are arranged so that they can come into contact with each other, and odd-numbered partitions counted from one end to the other end communicate with each other in one passage, and even-numbered partitions are connected to each other. The two paths are connected to an alternate supply / exhaust device, and the alternate supply / exhaust device sets the other path to the exhaust state when one path is in the supply state, and supplies the other path to the supply state. A filter device characterized in that one of the passages is evacuated when in the state. 5. A relative humidity reduction device for reducing the relative humidity of gas supplied to a passage in an air supply state.
The filtration device according to claim 1.