JP6971336B2 - Vacuum filtration method - Google Patents

Description

In the present invention, a filter cloth made to be able to travel in the horizontal direction by the driving means is arranged on the vacuum tray, and the slurry supplied on the filter cloth is sucked through the filter cloth by the vacuum tray. It relates to a vacuum filtration method using a horizontal belt filter type vacuum filtration device for filtering.

As a vacuum filtration method using such a horizontal belt filter type vacuum filtration device, for example, in Patent Document 1, a vacuum tray is used as a filter cloth under a filter cloth provided on the main body of the device so as to be able to travel substantially horizontally. A vacuum filtration method in which the slurry supplied on the filter cloth is vacuum-sucked through the filter cloth by a vacuum tray that advances in accordance with the running of the filter cloth. Is described.

Further, in Patent Document 2, the vacuum tray is fixed to the main body of the apparatus, the running of the filter cloth and the vacuum suction are performed intermittently, and the running of the filter cloth is stopped while the slurry is vacuum sucked. A vacuum filtration method using a horizontal belt filter type vacuum filtration device for filtering a slurry by running a filter cloth when vacuum suction is stopped is described.

Japanese Patent No. 36575550 Japanese Patent No. 3657551

Such a horizontal belt filter type vacuum filtration device has high cleaning performance specialized for cake cleaning, but on the other hand, since the filtration surface is a horizontal surface, the installation area is large compared to other filtration devices. There is a problem that a large installation area is required to increase the processing amount of the slurry. In addition, when installing a plurality of horizontal belt filter type vacuum filtration devices in order to increase the amount of slurry processed, the number of filter cloths and the number of drive means for running the filter cloths also increase in addition to the increase in the installation area. This will complicate management and maintenance.

Further, in the horizontal belt filter type vacuum filtration device, the filter cake can be replaced and washed, but when cleaning a substance having a poor cleaning property such as particles having a porous structure (porous particles), the replacement is performed. Cleaning may not be sufficient. In such a case, the reslurry cleaning (reslurry cleaning) of the filtered cake is often performed, but in order to perform the reslurry cleaning, it is still necessary to install a plurality of horizontal belt filter type vacuum filtration devices, or the horizontal belt. In addition to the filter-type vacuum filtration device, another type of filter or separator is required, which also leads to an increase in the installation area and an increase in the number of filters and driving means.

The present invention has been made under such a background, and even when the amount of slurry processed is increased or reslurry cleaning is performed, the increase in the installation area is suppressed and the number of filters and driving means is increased. It is an object of the present invention to provide a vacuum filtration method using a horizontal belt filter type vacuum filtration device capable of preventing the above.

In order to solve the above-mentioned problems and achieve such an object, in the present invention, a filter cloth made horizontally movable by a driving means is arranged on a vacuum tray, and the filter cloth is placed on the filter cloth. A vacuum filtration device that sucks and filters the supplied slurry through the filter cloth by the vacuum tray, in which a plurality of the vacuum trays are arranged side by side so as to overlap at least partially in the vertical direction and extend horizontally. In a vacuum filtration method using a vacuum filtration device in which one filter cloth is arranged so as to be travelable by one drive means between these vacuum trays. The slurry is supplied to and filtered on the side opposite to the traveling direction of the filter cloth on the vacuum tray, and the filtered cake obtained by filtering the slurry is discharged from the traveling direction side of the filter cloth, and the plurality of the above are discharged. The filtered cake filtered by at least one of the vacuum trays is discharged from the at least one vacuum tray, re-slurried, and filtered by the other at least one vacuum tray.

In the vacuum filtration method using the vacuum filtration device configured in this way, a plurality of vacuum trays are arranged side by side so as to extend in the horizontal direction so as to overlap at least partially in the vertical direction, and these. Since one filter cloth is movably arranged between the vacuum trays by one driving means, it is possible to secure a large filtration area while suppressing a large installation area of the device, and the slurry. The amount of processing can be increased.

On the other hand, if the processing amount of the slurry is the same, the traveling speed of the filter cloth can be reduced, the filtration time from the supply of the slurry to the discharge can be lengthened, and the filtration efficiency can be improved. .. Further, even if a plurality of vacuum trays are used in this way, only one filter cloth and drive means are required, so that the management and maintenance of these filter cloths and drive means can be simplified as compared with the case of using a plurality of vacuum filtration devices. It will be possible to achieve this.

Since a plurality of vacuum trays are arranged side by side so as to overlap at least partially in the vertical direction, it is also possible to re-filter the reslurry of the filter cake between these vacuum trays. It can be done with the device. That is, in the present invention, as described above, the filtered cake filtered by at least one of the plurality of vacuum trays is discharged from the at least one vacuum tray and resally, and the other vacuum tray is at least one. Since it is filtered by, it does not require another horizontal belt filter type vacuum filtration device, another type of filter, a separator, or the like. Here, the reslurry means to reslurry by supplying the reslurry liquid to the filtered cake and stirring or the like, and the reslurry washing means to filter the slurry thus reslurryed again.

In this case, the filtered cake filtered by the at least one vacuum tray is reslurried and filtered by the other at least one vacuum tray on the traveling direction side of the filter cloth of the at least one vacuum tray. As a result, resurrection and filtration can be performed sequentially and efficiently in the traveling direction of the filter cloth.

Further, the filtered cake filtered by the at least one vacuum tray may be reslurried by the filtrate sucked in the other at least one vacuum tray.

In particular, the filtered cake filtered by the at least one vacuum tray is resurrected by the filtrate sucked in the other at least one vacuum tray on the traveling direction side of the filter cloth of the at least one vacuum tray. The filtered cake can be resurrected by a relatively clear filtrate sucked in the vacuum tray at the subsequent stage of the filtered vacuum tray, and the consumption of the cleaning liquid (reslurry liquid) used for the reslurry can be suppressed.

Further, in the vacuum filtration method of the present invention, the filtered cake filtered by at least one of the plurality of vacuum trays is sucked into the vacuum tray on the traveling direction side of the filter cloth of the at least one vacuum tray. By replacing and washing with the obtained filtrate, it is also possible to replace and wash the filtered cake with a relatively clear filtrate for the filtered cake.

On the other hand, in the vacuum filtration device used in the vacuum filtration method of the present invention, since there is only one filter cloth, this filter cloth is tensioned between the plurality of vacuum trays by one filter cloth tensioning means. , The tension of the entire filter cloth can be maintained. Further, when performing replacement cleaning of the filtered cake as described above, cleaning means for replacing and cleaning the filtered cake on which the slurry has been filtered is provided on the filter cloth running on the plurality of vacuum trays. Just do it.

Further, when the filter cloth is wound around the rollers on the traveling direction side and the side opposite to the traveling direction of the plurality of vacuum trays, the roller on the traveling direction side is selected from among the plurality of vacuum trays. By arranging the vacuum tray on the upper side in a position protruding in the horizontal direction, the device is discharged below the roller on the protruding traveling direction side without making the height of the device higher than necessary. It is possible to easily secure a space for arranging a conveyor or the like for transporting the filtered cake.

Furthermore, in such a vacuum filtering device, the vacuum tray can be moved forward and backward as described in Patent Document 1 described above, and the slurry supplied on the filter cloth is advanced in accordance with the running of the filter cloth. A vacuum tray is used for vacuum suction through the filter cloth, and a vacuum tray is fixed to the main body of the apparatus as described in Patent Document 2, and the filter cloth is run and vacuum suction is performed intermittently. However, in the former case, if the plurality of vacuum trays are connected to each other and can be advanced and retreated in the horizontal direction by one advancing / retreating means, this advancing / retreating means can be done by one, which is efficient. ..

As described above, according to the present invention, it is possible to increase the amount of slurry processed without requiring a large installation area or increasing the number of filter cloths or the number of driving means, and 1 It is possible to perform reslurry cleaning of the filtered cake with two horizontal belt filter type vacuum filtration devices.

It is a schematic side view which shows the vacuum filtration apparatus used in 1st Embodiment of the vacuum filtration method of this invention. It is a schematic side view which shows the vacuum filtration apparatus used in the 2nd Embodiment of the vacuum filtration method of this invention. It is a schematic side view which shows the modification of the vacuum filtration apparatus shown in FIG. It is a schematic side view which shows the modification of the vacuum filtration apparatus shown in FIG.

FIG. 1 shows a vacuum filtration device used in the first embodiment of the vacuum filtration method of the present invention. In this vacuum filtering device, a plurality of (three-stage) rectangular box-shaped vacuum trays 1A to 1C having substantially the same shape and the same size are formed by arranging a plurality of vacuum suction chambers in the horizontal direction (horizontal direction in FIG. 1). , Both ends in the horizontal direction, which is the longitudinal direction thereof, are aligned and arranged so as to overlap in the vertical direction as a whole and extend in the horizontal direction. A large number of suction holes (not shown) are formed on the upper surface of the vacuum suction chambers of the vacuum trays 1A to 1C.

In this vacuum filtering device, the side surfaces of these vacuum trays 1A to 1C on the side at least one end (both ends in FIG. 1) are connected to each other by the tray connecting member 2, and the wheels are attached to a frame (not shown). It is supported by 3 and can move forward and backward in the horizontal direction. Further, in this vacuum filtration device, a cylinder device 4 as one advancing / retreating means in the vacuum filtration device is connected to the lowermost vacuum tray 1C, and the plurality of vacuum trays 1A to 1C are integrally connected by the cylinder device 4. It is possible to move forward and backward in the horizontal direction with a predetermined stroke.

Further, an entry-side roller 5A and an exit-side roller 5B are arranged on the outer sides of each of the vacuum trays 1A to 1C in the horizontal direction, and a pressing roller is placed on the vacuum trays 1A to 1C on the entry-side roller 5A side. 5C is arranged. In this vacuum filtration device, the horizontal positions of the entry side roller 5A, the exit side roller 5B, and the pressing roller 5C are aligned with each other in the plurality of vacuum trays 1A to 1C.

Further, below the lowermost vacuum tray 1C, a pair of tension rollers 6A and 6B as one filter cloth tensioning means 6 in the vacuum filtering device are arranged on the exit side roller 5B side of the vacuum tray 1C. In addition, the return roller 7 is arranged on the outer side in the horizontal direction from the entry side rollers 5A of the vacuum trays 1B and 1C in the middle and lower stages. In the filter cloth tensioning means 6, the tension rollers 6A and 6B are arranged in a stepped manner, and by adjusting the horizontal spacing between the tension rollers 6A and 6B, the entry roller 5A , The tension of the filter cloth 8 wound around the exit side roller 5B, the pressing roller 5C, and the return roller 7 is adjusted.

The entry side roller 5A, the exit side roller 5B, the holding roller 5C, the tension rollers 6A, 6B, and the return roller 7 are rotatably around the rotation axis extending vertically and horizontally in the longitudinal direction of the vacuum trays 1A to 1C. One long endless piece for each of the entry side roller 5A, the exit side roller 5B, and the holding roller 5C, and the tension rollers 6A, 6B, and the return roller 7 of each vacuum tray 1A to 1C. The belt-shaped filter cloth 8 is wound around the filter cloth 8 so that the filter cloth 8 can travel in the traveling direction indicated by reference numeral F in the drawing.

Here, the rotation axis of the entry side roller 5A and the pressing roller 5C is located above the upper surface of each of the vacuum trays 1A to 1C, and the rotation axis of the exit side roller 5B is the upper surface of each of the vacuum trays 1A to 1C. It is located below. On the upper surface side of each of the vacuum trays 1A to 1C, the filter cloth 8 is wound around the lower edge portion of the pressing roller 5C from the upper edge portion of the entry side roller 5A, and is wound from the vacuum tray 1A to the traveling direction F side. It extends along the upper surface of 1C and is wound around the exit roller 5B.

Further, the filter cloth 8 wound around the outlet roller 5B of the upper and middle vacuum trays 1A and 1B passes under each of the vacuum trays 1A and 1B and is in the opposite direction to the upper surface side. It extends in the lower traveling direction F and is wound around the inlet rollers 5A of the middle and lower vacuum trays 1B and 1C, respectively. Further, the filter cloth 8 wound around the outlet roller 5B of the lower vacuum tray 1C extends below the vacuum tray 1C, passes through the tension rollers 6A and 6B of the filter cloth tensioning means 6, and then returns. It is wound around and returned to the entry side roller 5A of the upper vacuum tray 1A. Therefore, in this vacuum filtration device, the filter cloth 8 filters while traveling from the upper vacuum tray 1A toward the lower vacuum tray 1C, and circulates so as to be returned to the upper vacuum tray 1A again.

Further, one of the entry side roller 5A, the exit side roller 5B, the pressing roller 5C, and the return roller 7 of each of these vacuum trays 1A to 1C is an electric motor (not shown) as one driving means in this vacuum filtration device. The motors are connected via a speed reducer, and the filter cloth 8 is driven by this drive means. Here, in this vacuum filtration device, this one driving means is connected to the outlet roller 5B of the lowermost vacuum tray 1C.

Further, above the filter cloth 8 traveling on each of the vacuum trays 1A to 1C, the pressing roller is on the side opposite to the traveling direction F of the filter cloth 8 and on the traveling direction F side of the pressing roller 5C. Supply means 9A to 9C for supplying the slurry SA to SC for each of the vacuum trays 1A to 1C are arranged on the filter cloth 8 at a position closer to 5C. Further, above the filter cloth 8 running on the vacuum trays 1A to 1C, the slurry SA to SC supplied on the filter cloth 8 is filtered to some extent at the substantially central portion in the longitudinal direction of the vacuum trays 1A to 1C. Cleaning means 10A to 10C for performing replacement cleaning by supplying cleaning liquids WA to WC to each of the vacuum trays 1A to 1C are provided on the filtered cakes CA to CC generated in the above process.

Furthermore, each of the vacuum suction chambers of the vacuum trays 1A to 1C is connected to a suction means (not shown) such as a vacuum pump that filters the slurry supplied on the filter cloth 8 through the filter cloth 8 and sucks the filtrate. The vacuum suction tubes 11A to 11C are connected to each other via a flexible tube or the like that follows the advance and retreat of the vacuum trays 1A to 1C in this vacuum filtration device. Further, a scraper 12 for peeling the filter cakes CA to CC adhering to the filter cloth 8 is provided on the lower edge of the outlet roller 5B of each of the vacuum trays 1A to 1C, and the scraper 12 is separated below the scraper 12. Conveyor conveyors 13 for transporting the filtered cakes CA to CC are arranged. Further, on the traveling direction F side of the filter cloth 8 with respect to the scraper 12 below each of the vacuum trays 1A to 1C, there is a cleaning device 14 for cleaning the filter cloth 8 from which the filter cakes CA to CC have been peeled off by spraying cleaning water. It is provided.

The filtered cakes CA to CC that have been filtered by the vacuum trays 1A to 1C, separated from the filter cloth 8 by the scraper 12, and transported by the transport conveyor 13 are collectively collected and subjected to processing such as drying. However, in the present embodiment, the filtered cakes CA and CB filtered by the upper vacuum tray 1A and the middle vacuum tray 1B are conveyed to the reslurry tanks 15A and 15B, respectively, and the reslurry liquids LB and LC are supplied. By being stirred, it is reslurried.

Further, in the vacuum filtration method of the present embodiment, the filtered cakes CA and CB thus reslurried are obtained by reslurrying the filtered cake filtered by at least one of the plurality of vacuum trays 1A to 1C. It is filtered by at least one vacuum tray. Specifically, the filtered cake CA filtered by the upper vacuum tray 1A is reslurried by the reslurry tank 15A to the filter cloth 8 on the middle vacuum tray 1B on the traveling direction F side of the upper vacuum tray 1A. The filter cake CB supplied as a slurry SB from the supply means 9B, filtered by the vacuum tray 1B in the middle stage, and reslurryed by the reslurry tank 15B is the vacuum in the lower stage on the traveling direction F side of the vacuum tray 1B in the middle stage. It is supplied to the filter cloth 8 on the tray 1C as a slurry SC from the supply means 9C and filtered.

Furthermore, in the present embodiment, the filtered cake filtered by at least one of the plurality of vacuum trays 1A to 1C is sucked by the vacuum tray on the traveling direction F side of the filter cloth 8 of the at least one vacuum tray. It is resurrected by the filtrate. Specifically, the filtered cake CA filtered by the upper vacuum tray 1A is a reslurry tank 15A in which a part of the filtrate sucked from the slurry SB by the middle vacuum tray 1B located on the traveling direction F side performs reslurry. The filtered cake CB that has been reslurried by being supplied as a reslurry liquid LB and filtered by the vacuum tray 1B in the middle stage is the filtrate sucked from the slurry SC by the lower vacuum tray 1C located on the traveling direction F side. A part of the reslurry is reslurried by being supplied as a reslurry liquid LC to the reslurry tank 15B.

Further, in the present embodiment, the filtered cake filtered by at least one of the plurality of vacuum trays 1A to 1C is sucked by the vacuum tray on the traveling direction F side of the filter cloth 8 of the at least one vacuum tray. It is replaced and washed with the filtrate. Specifically, in the filtered cake CA filtered by the upper vacuum tray 1A, the rest of the filtrate sucked from the slurry SB by the middle vacuum tray 1B located on the traveling direction F side is used as the cleaning liquid WA from the cleaning means 10A. In the filtered cake CB that has been supplied, replaced and washed, and filtered by the vacuum tray 1B in the middle stage, the rest of the filtrate sucked from the slurry SC by the vacuum tray 1C in the lower stage located on the traveling direction F side is washed as a cleaning liquid WB. It is supplied from the means 10B and is replaced and washed.

The filtrate LA sucked from the slurry SA by the upper vacuum tray 1A is processed without being used for reslurry or replacement washing in this embodiment. Further, as the cleaning liquid WC supplied from the cleaning means 10C to the filtered cake CC filtered by the lower vacuum tray 1C, water or the like clearer than the filtrate is used. Further, the filtered cake CC filtered by the lower vacuum tray 1C is conveyed and processed as it is.

In the vacuum filtration method of the present embodiment using the vacuum filtration device configured as described above, the filter cloth 8 is continuously traveled in the traveling direction F by the driving means, orbits as described above, and is a vacuum tray. 1A to 1C suck the slurry SA to SC supplied from the supply means 9A to 9C on the vacuum trays 1A to 1C on the side opposite to the traveling direction F of the filter cloth 8 by the suction means through the filter cloth 8. Then, while filtering, the filter cloth 8 and the traveling direction F move forward in synchronization with each other. The vacuum trays 1A to 1C may be advanced in synchronization with the filter cloth 8 by the cylinder device 4.

Further, when the vacuum trays 1A to 1C reach the forward stroke end, the suction by the suction means is released, and at the same time, the vacuum trays 1A to 1C are pulled back to the backward stroke end opposite to the traveling direction F by the cylinder device 4. While filtering the slurry SA to SC again by suction, the slurry moves forward in synchronization with the filter cloth 8. Further, the filter cakes CA to CC obtained by filtering the slurry SA to SC supplied on the filter cloth 8 are peeled off by the scraper 12 from the traveling direction F side as the filter cloth 8 travels, and are discharged to the transport conveyor 13. NS.

Then, in the vacuum filtration method using the vacuum filtration device having the above configuration, the plurality of vacuum trays 1A to 1C for filtering the slurry SA to SC are arranged side by side so as to be at least partially overlapped in the vertical direction and extend in the horizontal direction. Since it is arranged, it is possible to secure a large filtration area while suppressing a large installation area of the device. Therefore, even if the installation area is limited, it is possible to increase the processing amount of the slurry SA to SC.

On the other hand, by increasing the filtration area in this way, if the processing amount is the same, the traveling speed of the filter cloth 8 can be slowed down and the filtration time can be lengthened, so that efficient filtration can be performed. Will be. Further, even if a plurality of vacuum trays 1A to 1C are used in this way, in the vacuum filtration method using the vacuum filtration device having the above configuration, only one filter cloth 8 and its driving means are required. Therefore, for example, a plurality of vacuum filtration devices It is also possible to simplify the management and maintenance of the filter cloth 8 and the driving means as compared with the case where the same filtration area is secured by using.

Further, in the vacuum filtration device used in the vacuum filtration method of the present embodiment, since there is only one filter cloth 8 in this way, there is also one filter cloth tensioning means 6 for tensioning the filter cloth 8 to adjust the tension. It's fine. Further, in the vacuum filtration device used in the vacuum filtration method of the present embodiment, as described above, the vacuum trays 1A to 1C can be moved forward and backward in the horizontal direction by an advance / retreat means such as the cylinder device 4. Since the trays 1A to 1C are connected to each other by the tray connecting member 2, this advancing / retreating means may be one. Therefore, it is possible to simplify the management and maintenance of the filter cloth tensioning means 6 and the advancing / retreating means.

Moreover, in the vacuum filtration device used in the vacuum filtration method of the present embodiment, the driving means is connected to the outlet roller 5B around which the filter cloth 8 running on the lowermost vacuum tray 1C is wound, and the filter cloth is also used. The tensioning means 6 is arranged below the lowermost vacuum tray 1C, and the advancing / retreating means (cylinder device 4) is also connected to the lowermost vacuum tray 1C. Therefore, even if a plurality of vacuum trays 1A to 1C are arranged side by side so as to overlap each other in the vertical direction, management and maintenance of the driving means, the filter cloth tensioning means 6, and the advancing / retreating means may be a high-place work. It is possible to further simplify the process. Furthermore, since the vacuum trays other than the lowermost vacuum tray 1C are not provided with various means such as a driving means and a filter cloth tensioning means 6, the vacuum trays other than the lowermost vacuum tray 1C can be used in each stage. It can be unitized for each unit, and it becomes easy to increase or decrease the number of stages.

On the other hand, by using such a vacuum filtration device, in the vacuum filtration method of the above embodiment, the filtration cake CA filtered by the upper vacuum tray 1A among the plurality of vacuum trays 1A to 1C as described above is obtained. The filter cake CB that has been reslurried and filtered by the vacuum tray 1B in the middle stage can be resurrected and filtered by the vacuum tray 1C in the lower stage.

That is, between the plurality of vacuum trays 1A to 1C in one vacuum filtration device, the filtered cake filtered by at least one vacuum tray can be resurrected and filtered by the other at least one vacuum tray, so that it can be washed. A slurry containing particles having a poorly porous structure (porous particles) can be sufficiently washed, and another horizontal belt filter type vacuum filtration is used to filter the slurry obtained by re-slurrying the filtered cake in this way. It does not require equipment or other types of filters, separators, etc.

Further, in the present embodiment, in order to reslurry the filtered cake in this way, the filtered cake CA filtered by one of the upper vacuum trays 1A is reslurried, and the traveling direction of the filter cloth 8 with respect to the upper vacuum tray 1A. The filter cake CB filtered by the other vacuum tray 1B in the middle stage located on the F side is further filtered by the one vacuum tray 1B in the middle stage, and the filter cloth 8 with respect to the vacuum tray 1B in the middle stage is re-slurried. Filtration is performed by another vacuum tray 1C in the lower stage located on the traveling direction F side. Therefore, the slurry SA to SC are sequentially filtered and reslurried in the traveling direction F of the filter cloth 8 and efficiently processed, and the finally filtered filter cake CC is the lower vacuum tray 1C in the present embodiment. Is discharged from.

Further, in the present embodiment, the filtered cake CA filtered by the upper vacuum tray 1A is located on the traveling direction F side of the filter cloth 8 with respect to the upper vacuum tray 1A in order to reslurry the filtered cake in this way. A part of the filtrate sucked by the vacuum tray 1B in the middle stage is used as the reslurry liquid LB to be resurrected, and the filter cake CB filtered by the vacuum tray 1B in the middle stage is the filter cloth 8 with respect to the vacuum tray 1B in the middle stage. A part of the filtrate sucked by the lower vacuum tray 1C located on the traveling direction F side is used as the reslurry liquid LC and resurrected.

Therefore, the filtered cake is reslurried with a relatively clear filtrate for the filtered cake sucked by the subsequent vacuum trays 1B and 1C located on the traveling direction F side of the filtered vacuum trays 1A and 1B, respectively. Therefore, it is possible to efficiently perform the reslurry without supplying a new reslurry liquid to the vacuum filtration device for the reslurry.

Further, in the present embodiment, the filtered cakes CA to CC are also subjected to replacement cleaning on the plurality of vacuum trays 1A to 1C. Of the filtrate sucked by the middle-stage vacuum tray 1B located on the traveling direction F side of the upper-stage vacuum tray 1A, the remaining filtrate except for a part of the filtrate used as the reslurry liquid LB is used as the cleaning liquid WA. The filter cake CB filtered by the middle vacuum tray 1B is also a part of the filtrate sucked by the lower vacuum tray 1C located on the traveling direction F side of the middle vacuum tray 1B and used as the reslurry liquid LC. The remaining filtrate except the filtrate of is used as the washing liquid WB.

Therefore, even in this replacement cleaning, the filtered cake remains relatively clear with respect to the filtered cake sucked by the subsequent vacuum trays 1B and 1C located on the traveling direction F side of the filtered vacuum trays 1A and 1B, respectively. Since it will be washed with the filtrate, only the washing liquid WC for washing the filtered cake CC filtered by the lower vacuum tray 1C needs to be newly supplied to the vacuum filtering device for replacement washing, so that the consumption of the washing liquid is consumed. Can be suppressed, and replacement cleaning can be performed efficiently. In order to perform such replacement cleaning, the cleaning liquids WA to WC are supplied to the substantially central portion of the vacuum trays 1A to 1C in the longitudinal direction, for example, as in the vacuum filtration device used in the vacuum filtration method of the present embodiment. Cleaning means 10A to 10C such as nozzles may be provided respectively. Further, in FIG. 1, one cleaning means 10A to 10C is provided for each of the vacuum trays 1A to 1C in each stage, but a plurality of cleaning means 10A to 10C may be provided for the vacuum trays 1A to 1C. This makes it possible to obtain a higher cleaning effect.

Next, FIG. 2 shows a vacuum filtration device used in the vacuum filtration method of the second embodiment of the present invention, and is vacuum filtration used in the vacuum filtration method of the first embodiment shown in FIG. The same code is assigned to the parts common to the device. In the vacuum filtration device used in the first embodiment, the plurality of vacuum trays 1A to 1C can be moved forward and backward in the horizontal direction by the cylinder device 4 as the moving / retreating means, whereas the plurality of vacuum trays 1A to 1C are used in the second embodiment. In the vacuum filtration device, the plurality of vacuum trays 1A to 1C are fixed to the frame, and are not provided with advancing / retreating means. In this case, the plurality of vacuum trays 1A to 1C may not be connected by the tray connecting member 2, and the vacuum trays 1A to 1C and the vacuum suction pipes 11A to 11C are usually connected without a flexible tube or the like. It may be connected by a rigid pipe.

In the vacuum filtration device used in such a second embodiment, the filter cloths 8 arranged on the plurality of vacuum trays 1A to 1C and to which the slurry SA to SC are supplied have a predetermined pitch (for example, vacuum) by the driving means. It repeats running and stopping intermittently in the width of the running direction F for one suction chamber), and the suction means stops suction while the filter cloth 8 is running, and while the filter cloth 8 is stopped. The filtrate is sucked from the slurry SA to SC through the filter cloth 8 and filtered.

Further, also in the vacuum filtration device used in the second embodiment, the plurality of vacuum trays 1A to 1C are arranged side by side so as to overlap at least partially in the horizontal direction, and these vacuum trays 1A are arranged side by side. Since one filter cloth 8 is movably arranged between the 1Cs by one driving means, the installation area of the device becomes large as in the vacuum filtration device used in the first embodiment. It is possible to obtain the effect that a large filtration area can be secured while suppressing the pressure.

Further, FIGS. 3 and 4 show modified examples of the vacuum filtration device used in the first embodiment and the vacuum filtration device used in the second embodiment, respectively, and these first and second embodiments are shown. The same reference numerals are given to the parts common to the vacuum filtration device used in the embodiment. In the vacuum filtering device used in the first and second embodiments, the horizontal positions of the inlet roller 5A, the outlet roller 5B, and the presser roller 5C of the plurality of vacuum trays 1A to 1C are aligned with each other. On the other hand, in these modified examples, the outlet roller 5B located on the traveling direction F side of the filter cloth 8 on the vacuum trays 1A to 1C is horizontally oriented toward the upper vacuum tray among the plurality of vacuum trays 1A to 1C. It is arranged in a protruding position.

That is, as shown in FIGS. 3 and 4, the output roller 5B located on the traveling direction F side of the middle vacuum tray 1B is larger than the exit roller 5B located on the traveling direction F side of the lower vacuum tray 1C. The outlet roller 5B, which is arranged so as to project horizontally to the traveling direction F side and is located on the traveling direction F side of the upper vacuum tray 1A, is an exit side located on the traveling direction F side of the middle vacuum tray 1B. It is arranged at a position protruding horizontally from the roller 5B toward the traveling direction F side.

In the vacuum filtration device of the modified example configured in this way, it is possible to obtain the same effect as the vacuum filtration device used in the first and second embodiments, and of course, the higher the vacuum tray, the more the filtration cake is discharged. Since the exit side roller 5B to be formed is in a position protruding in the horizontal direction, a large space can be secured below the output side roller 5B. Therefore, even if a plurality of vacuum trays 1A to 1C are arranged so as to overlap each other in the vertical direction and extend in the horizontal direction, the height of the vacuum filtering device is not increased more than necessary, and the outlet roller is used. The transport conveyor 13 can be easily arranged below the 5B, and the installation space of the vacuum filtration device can be kept low even in the height direction.

When the outlet roller 5B is arranged at a position where it protrudes in the horizontal direction as much as the upper vacuum tray, there is a gap between the upper vacuum tray and the outlet roller 5B. Therefore, the vacuum suction chamber may be extended to this interval portion so that the upper vacuum tray becomes longer in the longitudinal direction. In this case, the plurality of vacuum trays partially overlap each other in the vertical direction.

Further, a plurality of vacuum trays 1A to 1C, an entry side roller 5A, an exit side roller 5B, and a pressing roller 5C are supported by a frame as in the vacuum filtration device used in the first and second embodiments and a modification thereof. In this case, this frame has the strength to be able to stand independently for each of the upper, middle, and lower vacuum trays 1A to 1C, their entry side rollers 5A, exit side rollers 5B, and pressing rollers 5C. It is desirable to assemble and integrate these at the installation site of the vacuum filtration device in consideration of the transportation of the device.

Further, in the vacuum filtration device and its modified examples used in the first and second embodiments, the vacuum trays 1A to 1C have three stages, but may be two stages or four or more stages.

1A ~ 1C Vacuum tray 2 Tray connecting member 4 Cylinder device (advancing / retreating means)
5A On-side roller 5B Out-side roller 5C Pressing roller 6 Filter cloth tension means 7 Return roller 8 Filter cloth 9A-9C Supply means 10A-10C Cleaning means 11A-11C Vacuum suction pipe 13 Conveyance conveyor 15A, 15B Reslurry tank F Filter cloth 8 SA-SC slurry CA-CC filter cake WA-WC cleaning liquid LA filtrate LB, LC reslurry liquid

Claims (5)

A vacuum tray is arranged on the vacuum tray so as to be able to travel in the horizontal direction by the driving means, and the slurry supplied on the filter cloth is sucked and filtered through the filter cloth by the vacuum tray. It ’s a filtration device,
The plurality of vacuum trays are arranged so as to align both ends in the horizontal direction, which is the longitudinal direction, so as to overlap each other in the vertical direction as a whole, and extend in the horizontal direction. In a vacuum filtration method using a vacuum filtration device in which a sheet of the filter cloth is arranged so as to be travelable by one drive means.
The slurry is supplied to and filtered on the side opposite to the traveling direction of the filter cloth on the plurality of vacuum trays, and the filtered cake obtained by filtering the slurry is discharged from the rear side of the filtering cloth in the traveling direction.
The filtered cake filtered by at least one of the plurality of vacuum trays is discharged from the at least one vacuum tray and transported to the reslurry tank to be reslurried in the reslurry tank, and the reslurryed filtered cake is obtained. It is supplied from the reslurry tank to at least one other vacuum tray for filtration, and at the same time.
The filtered cake filtered by at least one of the plurality of vacuum trays is sucked by the filtrate sucked in the other at least one vacuum tray on the rear side in the traveling direction of the filter cloth of the at least one vacuum tray. A vacuum filtration method characterized by replacement cleaning. The filtered cake filtered by the at least one vacuum tray is conveyed to the reslurry tank, reslurried in the reslurry tank, and the reslurryed filtered cake is used in the traveling direction of the filter cloth of the at least one vacuum tray. The vacuum filtration method according to claim 1, wherein the vacuum filtration method is characterized by supplying the slurry to at least one other vacuum tray on the subsequent stage side and filtering the slurry. Claim 1 is characterized in that the filtered cake filtered by the at least one vacuum tray is conveyed to the reslurry tank and reslurried by the filtrate sucked in the other at least one vacuum tray in the reslurry tank. Alternatively, the vacuum filtration method according to claim 2. The filtered cake filtered by the at least one vacuum tray is conveyed to the reslurry tank, and in the reslurry tank, the other at least one vacuum on the rear side in the traveling direction of the filter cloth of the at least one vacuum tray. The vacuum filtration method according to claim 3, wherein the vacuum filtration method is reslurried by the filtrate sucked in the tray. The traveling direction of the filter cloth for discharging the filtered cake filtered by the at least one vacuum tray is the traveling direction of the filter cloth for discharging the filtered cake filtered by the at least one other vacuum tray. The vacuum filtration method according to any one of claims 1 to 4, wherein the vacuum filtration method projects horizontally toward the traveling method side from the rear stage side.

Images