JP5912684B2 - Disc type filter - Google Patents

Description

  The present invention relates to a disk-type filtration device that mainly filters paper stock and sorts it out as foreign matter during the process of recycling used paper, and relates to a disk-type filtration device that prevents a reduction in filtration capability caused by the accumulation of foreign matter.

  In recent years, demands for resource conservation and global environmental conservation have increased, and the recycling rate of waste paper and waste paper has increased. In addition to magazines that have previously been difficult to deink and remove foreign matter, incompatible paper such as laminated paper containers that have been delivered from households and factories as burning garbage are now recycled as paper materials. It is coming. In the recycling of such a paper material, a paper material slurry is first made from waste paper or the like. For example, a continuous pulper described in Patent Document 1 proposed by the present applicant is used. In the continuous pulper, the stock is poured into the solution in which water or chemicals are injected into the vertical cylindrical container and dissolved, and the stock is gradually disaggregated by the stirring of the stirring rotor, thereby producing a uniform stock slurry. It is done.

  Paper slurry made with a continuous pulper is sent to a filtration device, where foreign matter is sorted. As a filtering device, for example, there is a disk type filtering device disclosed in Patent Document 2 proposed by the present applicant. Clogging is less likely to occur than with a Jansson screen, and therefore continuous processing is possible without stopping operation. In this disk type filtration device, the fed paper slurry is diluted with dilution water, and the paper slurry is filtered by a disk screen arranged at the bottom of the dilution stirring tank. A stirrer rotor rotates with a slight gap on the disk screen to stir the paper slurry containing foreign matter.

JP 2003-193383 A JP 2007-016377 A

  By the way, the contraindicated waste paper may contain many foreign matters such as vinyl strings and plastic products in addition to the laminate film which is not a raw material of paper. When a material containing a large amount of such foreign substances is used as a raw material, the foreign substances may become entangled and coarsened before being discharged, and may stay in the dilution stirring tank. In the diluting stirring tank in which coarsened foreign matter stays, foreign matter is caught between the disc screen and the stirring rotor, and the processing capacity of the disc type filtration device is lowered. Moreover, if the foreign matter stays, the liquid level in the dilution stirring tank will not be lowered. Then, since the supply of the new paper slurry fed according to the liquid level is stopped, the processing amount is reduced.

  In order to solve such problems, it is conceivable to remove foreign substances in advance, but some of the raw materials to be processed may be classified and the work load may increase. It has not been confirmed. Therefore, the operator monitors the inside of the dilution stirring tank during operation and periodically removes coarsened foreign matters. However, because the growth of stagnant material differs depending on the foreign material contained, the number of monitoring of the worker will increase, and if the frequency of monitoring is reduced to reduce the burden, if the foreign material becomes too large, The operation is temporarily stopped and the work is taken out.

  Accordingly, an object of the present invention is to provide a disk-type filtration device that automatically eliminates coarsening foreign matters in order to solve such problems.

  In the disk-type filtration device according to the present invention, the dilution stirring tank for storing the diluted paper slurry is a slurry port for supplying the paper slurry, a dilution water port for supplying the dilution water, and a discharge port for discharging foreign matter. , A gate serving as a weir in front of the discharge port, and a bottom provided with a disk screen that allows only the paper slurry excluding foreign matter to pass through, and a stirring rotor that rotates on the disk screen A stock slurry supply means for supplying a stock slurry to the dilution agitation tank, a dilution water supply means for supplying dilution water to the dilution agitation tank, and a detection means for detecting a state in the dilution agitation tank And a control means for driving and controlling the paper slurry supply means and the dilution water supply means based on a detection signal from the detection means, and the control means is based on a detection signal of the detection means. There is judged the coarsening of the foreign matter of the diluted stirred tank and characterized in that it is obtained by so as to control the paper stock slurry feed means and the dilution water supply means at a predetermined timing.

Further, in the disk type filtration apparatus according to the present invention, when the control means determines that the foreign matter in the dilution stirring tank has become coarse based on the detection signal of the detection means, the paper slurry supply means Is stopped, the dilution water is supplied from the dilution water supply means, and it is determined that the coarsened foreign matter has been removed, the driving of the paper slurry supply means is resumed. preferable.
Further, in the disk type filtration apparatus according to the present invention, a discharge pipe through which the paper slurry that has passed through the disk screen is sent is connected to the dilution stirring tank, and a liquid level control valve is provided in the discharge pipe, The control means closes the liquid level control valve when it is determined that the foreign matter in the dilution agitation tank has become coarse based on the detection signal of the detection means, and when it is determined that the coarse foreign matter has been removed. Preferably, the liquid level control valve is opened.

In the disc type filtration apparatus according to the present invention, it is preferable that the detection means detects a load applied to a drive motor that rotates the stirring rotor.
Further, in the disk type filtration apparatus according to the present invention, when the control unit determines that the foreign matter in the dilution agitation tank has become coarse based on the detection signal of the detection unit, the coarse foreign matter is excluded. In each of the cases where it is determined that the determination has been made, it is preferable to check whether or not the determined state is maintained for a predetermined time.
Further, the disk type filtration device according to the present invention has a level sensor for detecting the liquid level in the dilution stirring tank, and the control device calculates the liquid level based on a detection signal from the level sensor, It is preferable that supply of dilution water from the dilution water supply means is stopped when a predetermined threshold value is exceeded.

  According to the present invention, the coarsening of the foreign matter in the dilution agitation tank is determined based on the detection signal from the detection means, the paper slurry supply means is stopped, and the dilution water is supplied from the dilution water supply means to By raising the surface, it is possible to automatically discharge the coarsened foreign matter over the gate.

It is sectional drawing which showed embodiment of the disk type filtration apparatus. It is the block diagram which showed the structure for performing the automatic removal of a coarsening foreign material. It is the figure which showed the automatic removal flow of the coarsening foreign material. FIG. 4 is a diagram showing a flow of automatically removing coarsened foreign matters to which a confirmation step has been added, and shows only a part of the flow in addition to the flow shown in FIG. 3. FIG. 4 is a diagram showing a flow of automatically removing coarsened foreign matters to which a confirmation step has been added, and shows only a part of the flow in addition to the flow shown in FIG. 3.

  Next, an embodiment of a disk-type filtration device according to the present invention will be described below with reference to the drawings. The disk-type filtration device of this embodiment is on the downstream side of the continuous pulper, and performs a filtration process by receiving a paper slurry sent from the upstream side. The continuous pulper is filled with a solution by injecting water or chemicals into a vertical cylindrical container, and as described above, a paper material including contraindicated waste paper is charged. The stock is gradually disaggregated by the stirring rotor, dissolved in the solution, and taken out through the take-out pipe as a stock slurry. Then, the stock slurry is fed into the disk type filtration device of the present embodiment disposed on the downstream side of the continuous pulper.

  FIG. 1 is a cross-sectional view showing the configuration of the disk type filtration device of the present embodiment. The disk type filtration apparatus 1 has a dilution stirring tank 10 for storing a processing liquid W diluted with a paper slurry, and a slurry port 101 and a dilution water port 102 are formed therein. The continuous pulper is formed with an extraction pipe having a screw feeder at the bottom of the container and connected to the slurry port 101. Accordingly, a predetermined amount of the paper slurry S is supplied from the slurry port 101 by the screw feeder, while the dilution water K is supplied from the dilution water port 102, and the paper material concentration of the paper slurry S is reduced in the dilution stirring tank 10. It is diluted.

  In the dilution agitation tank 10, a deep filtration part 110 is formed at the center so that the treatment liquid W can be accumulated. A disk screen 12 for filtering the paper slurry S is disposed at the bottom of the filtering unit 110, and the stirring rotor 11 is configured to rotate with a slight gap therebetween. The disk screen 12 is a punching metal filter that blocks the passage of foreign matter in the processing liquid W, and closes the chamber 21 provided under the filtration unit 110. The chamber 21 is connected to a discharge pipe 22 for sending the filtered paper slurry S to the next process.

  The stirring rotor 11 has four stirring blades spread radially and rotates on the disk screen 12. Therefore, the stirring rotor 11 is fixed to the upper end of the rotatable shaft 13. The shaft 13 protrudes downward from the dilution agitation tank 10 and the rotation of the drive motor 15 is transmitted. A bearing stand 16 is suspended from the dilution agitation tank 10, and a drive motor 15 and a cover 18 are attached thereto. The bearing stand 16 has two bearings 17 fixed at the top and bottom, and the shaft 13 is rotatably supported by the bearings 17. The rotation of the shaft 13 and the drive motor 15 is transmitted by a pulley and a V-belt housed in the cover 18. In addition, the location where the shaft 13 penetrates the dilution stirring tank 10 is sealed by a packing box 23 having a lantern ring for preventing leakage and a gland packing.

  In the dilution agitation tank 10, a gate 25 is formed on the opposite side of the slurry port 101 and the dilution water port 102 so that the processing liquid W can be stored. The gate 25 is a weir, and a discharge port 103 is formed at a position beyond the gate. The discharge port 103 is connected to a filtration device such as a vibrating screen installed on the downstream side. The gate 25 is inclined to the discharge port 103 side, and a water supply port 26 is formed below the gate 25. A guide plate 27 is attached to the position of the water supply port 26, and the water fed from the water supply port 26 flows vigorously along the inclined surface of the gate 25, and the water pressure P for allowing foreign matters floating on the liquid surface to cross the gate 25. It is comprised so that.

  Accordingly, among the foreign matters contained in the processing liquid W, the lightweight foreign matter N that floats on the liquid surface gets over the gate 25 by the pushed water P and flows to the discharge port 103. On the other hand, heavy foreign matter M that sinks is also included in the processing liquid W, and a recovery pipe 28 that collects the heavy foreign matter M is formed at the bottom of the dilution stirring tank 10. The recovery pipe 28 has a mouth formed under the gate 25, and a recovery tank (not shown) is connected to the end extending downward. The heavy foreign matter M sinking to the bottom of the dilution agitation tank 10 falls into the recovery pipe 28 and is collected in the recovery tank.

  Therefore, during the operation of the disk type filtration device 1, it is preferable that the lightweight foreign matter N is sent to the discharge port 103 and the heavy foreign matter M is recovered from the recovery pipe 28 in the recovery tank. However, depending on the stock to be processed, a large amount of foreign matter is contained, and these are entangled in the processing liquid W to become coarse foreign matter H. May stay. In this embodiment, such coarse foreign matter H is automatically excluded from the discharge port 103.

  In the automatic exclusion of the present embodiment, the diluting water K is added to the dilution agitation tank 10 to increase the liquid surface height of the processing liquid W so that the coarse foreign matter H can easily get over the gate 25. is there. FIG. 2 is a block diagram showing a configuration for executing automatic removal of coarse foreign matters. First, the stock slurry S is fed into the dilution stirring tank 10 from the continuous pulper through the screw feeder. Accordingly, the supply adjustment of the paper slurry S is performed by the feed motor 31 of the screw feeder.

  On the other hand, the dilution agitation tank 10 has a dilution water injection valve 32 that adjusts the supply amount of the dilution water K from the dilution water port 102 and a liquid level control for adjusting the amount of the dilution water K in the dilution agitation tank 10. A valve 33 is provided. As shown in FIG. 1, the filtered paper slurry S flows from the chamber 21 below the dilution stirring tank 10 to the discharge pipe 22, but the liquid level control valve 33 is disposed at the tip of the discharge pipe 22. ing. That is, the stock slurry S filtered by the disk screen 12 is drawn out by a vacuum device to a tank downstream thereof, but the liquid level control valve 33 is provided between the dilution agitation tank 10 and a tank (not shown). Is provided.

  In addition to the feed motor 31, the dilution water injection valve 32, and the liquid level control valve 33, the disk-type filtration device 1 is provided with a control device 30 that performs drive control of the drive motor 15 that rotates the stirring rotor 11. ing. The control device 30 is connected to a load detection sensor 35 for detecting the load of the stirring rotor 11 and a level sensor 36 for detecting the liquid level of the processing liquid W.

  The load detection sensor 35 detects the amount of change in the current value when the drive motor 15 is a DC motor, and detects the amount of change in the rotational speed when the drive motor 15 is an AC motor. That is, the resistance applied to the stirring rotor 11 rotating in the processing liquid W is detected. Further, for example, a differential pressure transmitter is used for the level sensor 36 and detects the liquid level of the processing liquid W in the dilution stirring tank 10 continuously and in real time. In addition, the level sensor 36 may be a pressure sensor that is installed on the bottom surface of the stirring tank and measures the liquid level from the pressure applied by the processing liquid W in the tank.

  Next, the operation of the disk type filtration device 1 will be described. First, in the continuous pulper upstream of the disk-type filtration device 1, the stock is put into a solution into which water or chemicals are injected, and the stock is melted to produce a stock slurry S. The stock slurry S is sent from the slurry port 101 to the disc type filtration device 1 by the rotation of the screw feeder. In the disk type filtration device 1, the stock slurry S is fed into the dilution stirring tank 10, and the dilution water K is supplied from the dilution water port 102. Therefore, in the disk-type filtration device 1, the treatment treatment W is obtained by thinning the paper slurry S to a low concentration.

  The liquid level in the dilution agitation tank 10 is detected by the level sensor 36, and the supply amount of the paper slurry S fed from the continuous pulper is adjusted according to the liquid level height calculated based on the detection signal. For example, the liquid surface height of the processing liquid W is set lower than that of the gate 25 as shown in FIG. 1, and if the set value is exceeded, rotation of the screw feeder is stopped or the rotation speed is suppressed, and the paper slurry S The supply amount is adjusted. On the other hand, the supply amount of the dilution water K to the dilution stirring tank 10 is adjusted by opening and closing the dilution water injection valve 32, which is linked to the supply amount of the paper slurry S by the screw feeder. For example, the stock slurry S fed from the continuous pulper at a concentration of 15 to 20 percent is mixed with the diluting water K in the disc type filtration device 1 and diluted to a concentration of 2 to 4 percent.

  The treatment liquid W in the dilution agitation tank 10 is agitated on the disk screen 12 as the agitation rotor 11 rotates. The chamber 21 side beyond the disk screen 12 is under negative pressure by a vacuum device (not shown). Therefore, the processing liquid W passes through the disk screen 12, and the paper material slurry S from which foreign matter has been removed is collected into a tank (not shown). On the other hand, the heavy foreign matter M that sinks to the bottom of the dilution stirring tank 10 does not stay on the disk screen 12 by the rotating stirring rotor 11 but falls to the recovery pipe 28 and is recovered.

  In addition, lightweight foreign matter N is floating on the liquid level of the processing liquid W accumulated in the dilution agitation tank 10. The stock slurry S and dilution water K are fed into the dilution agitation tank 10 from the slurry port 101 and dilution water port 102. At the opposite gate 25, the water push P from the water supply port 26 moves upward along the inclined surface. It is blowing out. Therefore, the lightweight foreign matter N flows to the gate 25 side, is pushed over the gate 25 by the pushed water P, and flows from the discharge port 103 to the next process. At this time, it is sufficient if the lightweight foreign matter N is small, but if it is entangled and coarsened, it cannot easily get over the gate 25 and stays.

  Since the liquid level of the processing liquid W during normal operation is at a position lower than the height of the gate 25, the coarsened foreign matter becomes heavy, and the gate 25 cannot be overcome only by the momentum of the pushing water P. Therefore, in the disk-type filtration device 1, the coarse foreign matter is automatically removed by the control device 30. FIG. 3 is a diagram showing an automatic removal flow of coarsened foreign matters. The control device 30 has an automatic exclusion program for executing this automatic exclusion flow.

  The load detection sensor 35 constantly detects the current value of the drive motor 15 that is, for example, a DC motor, and the control device 30 calculates the load value of the drive motor 15 that rotates the stirring rotor 11 based on the detection signal. The Various items such as wire pieces, clips, and vinyl strings are entangled in the coarsened foreign matter H, and the weight is, for example, about 30 kg. Then, foreign matter hits or bites the stirring rotor 11 at the bottom of the dilution stirring tank 10 to become resistance. In the present embodiment, the timing at which the coarse foreign matter H should be discharged is determined based on the rotational resistance of the stirring rotor 11 determined from the current value of the drive motor 15.

  In the control device 30, it is always checked whether the load value of the drive motor 15 exceeds the set value (S101). If the load value is equal to or less than the set value (S101: NO), it is determined that the foreign matter is not so coarse, normal operation is continued, and the load value is repeatedly checked. On the other hand, when the load value exceeds the set value (S101: YES), automatic removal of the coarse foreign matter H is executed. The automatic removal of the coarse foreign matter H is the discharge to the discharge port 103. For this purpose, the liquid level of the treatment liquid W in the dilution agitation tank 10 is raised above the gate 25 by adding the dilution water K, and a state in which the coarse foreign matter H exceeds the gate 25 is created.

  First, the driving of the feed motor 31 is stopped, and the supply of the paper slurry S by the screw feeder is stopped (S102). This is to prevent further foreign matter from being introduced into the dilution stirring tank 10 and prevent the paper slurry from being discharged from the discharge port 103. At this time, since the filtration process is also temporarily stopped, the liquid level control valve 33 is closed (S103). And it is necessary to be careful that the processing liquid W does not overflow from the dilution stirring tank 10. This is because, depending on the factory, the supply flow rate of the dilution water K is not stable, and the processing liquid W may exceed the capacity of the dilution stirring tank 10 by closing the liquid level control valve 33.

  In the control device 30, the liquid level is calculated based on the detection signal from the level sensor 36. Then, since the predetermined height is set as the threshold value so that the processing liquid W does not overflow the dilution stirring tank 10, it is confirmed whether or not the liquid level actually exceeds the threshold value (S104). ). When the liquid surface height exceeds the threshold value (S104: YES), the dilution water injection valve 32 is completely closed (S105). On the other hand, when the liquid level does not exceed the threshold (S104: NO), the open state of the dilution water injection valve 32 is controlled (S106). That is, the opening degree of the dilution water injection valve 32 is adjusted so that the liquid level is high enough to discharge the coarse foreign matter H within a range not exceeding the threshold value.

  Next, based on the detection signal from the load detection sensor 35, it is confirmed whether or not the load value of the drive motor 15 has fallen below the set value (S107). If it exceeds the set value (S107: NO), the control in steps S104 to S107 is repeated. At this time, the liquid level of the processing liquid W exceeds the gate 25 due to the increase of the dilution water K, and the floating coarse foreign matter H easily flows to the discharge port 103 side. Then, the rotational resistance of the stirring rotor 11 is reduced by actually flowing and being excluded from the processing liquid W in the dilution stirring tank 10.

  When the load value of the drive motor 15 falls below the set value (S107: YES), the operation is switched to normal operation. The liquid level control valve 33 that has been closed is opened, and the collection of the paper slurry S filtered through the disk screen 12 is resumed (S108). Further, the feed motor 31 is also driven to rotate the screw feeder (S109), and the opening of the dilution water injection valve 32 is adjusted in consideration of the liquid level height of the processing liquid W and the concentration of the paper slurry S (see FIG. S110). When returning to normal operation in this way, it is confirmed again whether the load value of the drive motor 15 exceeds the set value (S101), and the above operation is repeated.

  According to the disk type filtration device 1 of the present embodiment, the coarseness of the foreign matter in the dilution stirring tank 10 is confirmed by detecting the current value of the drive motor 15 and the liquid level is raised by supplying the dilution water K. This makes it possible to automatically discharge the coarse foreign matter H that exceeds the gate 25. For this reason, foreign matter accumulates in the dilution agitation tank 10, and problems such as temporarily stopping the disk-type filtration device 1 for discharging are eliminated, and stable operation is possible, thereby improving processing capacity. become. Further, the automatic removal of the coarse foreign matter H reduces the biting of the foreign matter between the stirring rotor 11 and the disk screen 12, thereby avoiding damage due to wear of parts and extending the life. Further, by automatically removing the coarse foreign matter H, the burden on the operator can be greatly reduced by omitting the operator's monitoring and removal work.

  By the way, in this embodiment, it is confirmed that the load value of the drive motor 15 has exceeded the set value in step S101 in FIG. However, if it is determined only by a temporary confirmation, there is a risk that automatic exclusion will be executed even if it is not necessary. In addition, when the automatic removal is performed, the filtration processing of the paper slurry S is stopped, which causes a reduction in the processing amount. Therefore, it is preferable to confirm that the state where the load value of the drive motor 15 exceeds the set value continues. FIG. 4 is a diagram showing a flow of automatic removal of coarse foreign matters to which the confirmation step is added, and shows only a part of the flow in addition to the flow shown in FIG.

  As described above, the control device 30 always checks whether the load value of the drive motor 15 exceeds the set value (S101). If the load value exceeds the set value (S101: YES), it is then confirmed that the state continues for a certain time (for example, 1 minute) (S1010). Therefore, until time elapses (S1010: NO), the process returns to step S101. For example, when the load value exceeds the set value for a moment (S101: NO) for some reason, the normal operation is continued. The load value check is repeated. On the other hand, when the state where the load value exceeds the set value continues for one minute (S101: YES, S1010: YES), the process proceeds to the next step S102, and the supply of the paper slurry S by the screw feeder is stopped. The subsequent control from step S103 to step S110 is as described above.

  Therefore, by confirming that the state in which the load value of the drive motor 15 exceeds the set value continues for a certain period of time, it is possible to reliably determine that it is necessary to automatically remove the coarse foreign matter H. it can. Therefore, it is possible to avoid a reduction in processing capacity without unnecessarily stopping the filtration processing of the paper slurry S.

  In step S107 of FIG. 3, it is confirmed that the load value of the drive motor 15 has fallen below the set value, and the operation is switched to normal operation (S108 to S110). However, even at this time, if the discharge state of the foreign matter in the dilution agitation tank 10 is determined only by a temporary confirmation, the normal operation may be resumed when the discharge is not sufficient. In such a case, automatic discharge is immediately repeated, resulting in a decrease in processing capacity. Therefore, it is preferable to confirm that the state in which the load value of the drive motor 15 is lower than the set value continues even when returning to normal operation. FIG. 5 is a diagram showing an automatic removal flow of coarse foreign matters to which the confirmation step is added, and shows only a part of the flow in addition to the flow shown in FIG.

  In the control device 30, it is confirmed whether or not the load value of the drive motor 15 has fallen below the set value based on the detection signal from the load detection sensor 35 (S107). If the load value of the drive motor 15 falls below the set value (S107: YES), then it is confirmed that the state continues for a certain time (for example, 1 minute) (S1070). Therefore, the process returns to step S107 until the time has elapsed (S1070: NO). At this time, if the load value only falls below the set value for a moment for some reason (S107: NO), the control of steps S104 to S107 shown in FIG. 3 is repeated. On the other hand, when the state where the load value is lower than the set value continues for one minute (S107: YES, S1070: YES), the operation is switched to the normal operation (S108 to S110).

  Therefore, by confirming that the state where the load value of the drive motor 15 is lower than the set value continues for a certain time, it is possible to determine that the automatic removal of the coarse foreign matter H has been completed. For this reason, it is possible to avoid a decrease in processing capability without unnecessarily repeating automatic exclusion and stoppage.

As mentioned above, although embodiment of the disk type filtration apparatus concerning this invention was shown, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, in the above-described embodiment, the coarsening of the foreign matter is determined by checking the load value of the drive motor 15, but the coarsening of the foreign matter is also determined from the change in the liquid level obtained from the level sensor 36. You may make it judge. This is because when the liquid level in the dilution agitation tank 10 does not change substantially for a certain period of time, the rotation of the agitation rotor 11 is limited by the presence of the coarsened foreign matter H, and the filtration does not proceed.

DESCRIPTION OF SYMBOLS 1 Disc type filtration apparatus 10 Dilution stirring tank 11 Stirring rotor 12 Disk screen 15 Drive motor 21 Chamber 25 Gate 30 Controller 31 Feeding motor 32 Dilution water injection valve 33 Liquid level control valve 35 Load detection sensor 36 Level sensor 101 Slurry port 102 Dilution water port 103 Discharge port

Claims (3)

The dilution agitation tank for storing the diluted material slurry is a slurry port for supplying the material slurry, a dilution water port for supplying the dilution water, a discharge port for discharging foreign matter, and a weir before the discharge port. In the disc-type filtration device provided with a gate and a disc screen that allows passage of only the paper slurry from which foreign substances have been removed and a stirring rotor that rotates on the disc screen at the bottom,
Paper slurry supply means for supplying a paper slurry to the dilution agitation tank, dilution water supply means for supplying dilution water to the dilution agitation tank, detection means for detecting the state in the dilution agitation tank, and the detection Control means for driving and controlling the paper slurry supply means and the dilution water supply means based on a detection signal from the means,
The control means judges the coarsening of the foreign matter in the dilution agitation tank based on the detection signal of the detection means, and controls the paper slurry supply means and dilution water supply means at a predetermined timing. that is,
The dilution agitation tank is connected to a discharge pipe through which the paper slurry that has passed through the disk screen is sent, and the discharge pipe is provided with a liquid level control valve,
The control means closes the liquid level control valve when judging that the foreign matter in the dilution agitation tank has become coarse based on the detection signal of the detection means, and judges that the coarse foreign matter has been removed The disc type filtration device is characterized in that the liquid level control valve is opened . The dilution agitation tank for storing the diluted material slurry is a slurry port for supplying the material slurry, a dilution water port for supplying the dilution water, a discharge port for discharging foreign matter, and a weir before the discharge port. In the disc-type filtration device provided with a gate and a disc screen that allows passage of only the paper slurry from which foreign substances have been removed and a stirring rotor that rotates on the disc screen at the bottom,
Paper slurry supply means for supplying a paper slurry to the dilution agitation tank, dilution water supply means for supplying dilution water to the dilution agitation tank, detection means for detecting the state in the dilution agitation tank, and the detection Control means for driving and controlling the paper slurry supply means and the dilution water supply means based on a detection signal from the means,
The control means judges the coarsening of the foreign matter in the dilution agitation tank based on the detection signal of the detection means, and controls the paper slurry supply means and dilution water supply means at a predetermined timing. that is,
The detection means detects a load applied to a drive motor for rotating the stirring rotor;
In each of the cases where the control means determines that the foreign matter in the dilution agitation tank has become coarse based on the detection signal of the detection means, and the case where it is determined that the coarse foreign matter has been removed, A disc-type filtration device characterized in that it is confirmed whether or not each of the determined states is maintained for a predetermined time . In the disk-type filtration device according to claim 1 or 2 ,
A level sensor for detecting a liquid level in the dilution agitation tank; and the control means calculates the liquid level based on a detection signal from the level sensor, and when the dilution water exceeds a predetermined threshold, A disk-type filtration device characterized in that the supply of dilution water from the supply means is stopped.

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