Screw press dewatering machine used in waste treatment equipment

Abstract

This invention provides a technology for efficiently discharging treated materials from a screw press dewatering machine used in a waste treatment system. [Solution] The dewatering device 60 comprises an inlet 62 into which crushed pieces F of the material to be processed flow in, a cylindrical screen section 66 whose upstream end is connected to the inlet 62, and screw blades 67B arranged inside the inlet 62 and the screen section 66, extending in the direction of the central axis of the screen section 66. The outer peripheral edge of the screw blades 67B has a notched portion 67C cut out from the upstream end F1 of the screen section 66 toward the downstream end F2.

Description

Technical Field

[0001] The present disclosure relates to a screw press dehydrator used in a sewage treatment device.

Background Art

[0002] Patent Document 1 discloses a technique for recovering pulp fibers from used absorbent articles.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Patent Document 1 compresses and dehydrates pulp fibers and the like using a third separation device (screw press dehydrator). When using a screw press dehydrator, if the shape of the object to be treated is a long strip in one direction, the object to be treated may get entangled with the screw blades so as to straddle the outer edge of the screw blades. In such a case, there is a concern that the object to be treated will rotate together while being entangled with the screw blades and remain in the screw press dehydrator without being conveyed. For this reason, a technique for satisfactorily discharging the object to be treated from the screw press dehydrator regardless of the outer shape of the object to be treated is desired.

[0005] The present disclosure has been made in view of the above conventional situation, and an object to be solved is to provide a technique for satisfactorily discharging an object to be treated from a screw press dehydrator used in a sewage treatment device.

Means for Solving the Problems

[0006] The screw press dewatering machine used in the waste treatment apparatus of the present disclosure comprises an inlet into which crushed pieces of the material to be treated flow in, a cylindrical screen section with its upstream end connected to the inlet section, and screw blades arranged within the inlet section and the screen section and extending in the direction of the central axis of the screen section, wherein the outer peripheral edge of the screw blades has a notch cut out from the upstream end to the downstream end of the screen section. [Brief explanation of the drawing]

[0007] [Figure 1] This is a front view showing the configuration of the waste treatment device according to Embodiment 1. [Figure 2] This is a plan view of the deodorizing device. [Figure 3] This is a cross-sectional view along line XX in Figure 1. [Figure 4] This is a plan view of the water release device. [Figure 5] Figure 4 is a cross-sectional view along the YY line. [Figure 6] This is an enlarged side cross-sectional view of a water release device. [Figure 7] This is an enlarged perspective view showing the second nozzle. [Figure 8] This is a magnified view of the outlet from the right side. [Figure 9] This is an enlarged side cross-sectional view of a dewatering device. [Figure 10] This is a cross-sectional view of a dehydrator. [Figure 11] Figure 10 is a cross-sectional view along the ZZ line. [Figure 12] Figure 10 is a cross-sectional view along the UU line. [Figure 13] Figure 10 is a cross-sectional view along the QQ line. [Figure 14] This is a plan view of a dewatering machine that performs conveyance control to transport crushed pieces. [Figure 15] This is a cross-sectional view of a dewatering machine that performs blockage clearing control. [Figure 16] This is a flowchart of the water release process and the dewatering process. [Figure 17]This flowchart shows the control of transport control and blockage clearing control. [Figure 18] This is a perspective view showing the nozzle configuration in another embodiment. [Modes for carrying out the invention]

[0008] <Embodiment 1> Hereinafter, Embodiment 1 of the waste treatment device 10 of this disclosure will be described with reference to Figures 1 to 17. In the following description, the up and down directions will be defined as upward and downward as shown in Figure 1. The left and right directions will be defined as left and right as shown in Figure 1. The front and back directions will be defined as downward and backward as shown in Figures 2, 3, and 4.

[0009] The waste disposal device 10 is a device that processes used disposable diapers D, which are the materials to be processed, for disposal. The waste disposal device 10 is installed in nursing care facilities and the like where multiple used disposable diapers D are generated irregularly at different times.

[0010] The disposable diapers D to be processed contain super absorbent polymer P (SAP, hereinafter simply referred to as polymer P) and pulp within a sheet material S such as a nonwoven fabric. The sheet material S has a surface layer made of polypropylene nonwoven fabric or the like, and a waterproofing material made of a resin material such as polyethylene. Pulp and polymer P are sandwiched between the surface layer and the waterproofing material. Pulp and polymer P have water absorption properties to absorb moisture from waste such as human waste, and water retention properties to maintain the absorbed moisture state. The sheet material S contains a resin material such as polypropylene or polyethylene with a density lower than that of water. Before absorbing moisture, the particle size of polymer P is 150 to 600 μm, and its density is greater than that of water. After absorbing moisture, polymer P swells and becomes gel-like, and the particle size of polymer P in the absorbed state is 600 μm to 4 mm. The objects to be processed in the waste treatment device 10 are sanitary products. Sanitary products include disposable diapers, napkins, pet sheets, etc.

[0011] The treatment of used paper diapers D is carried out through a crushing process of crushing the paper diapers D, a water separation treatment process of separating moisture from the polymer P in a water-absorbed state, and a dehydration process. In the dehydration process, waste liquid such as the treatment liquid T used in the water separation treatment process and the moisture separated from the polymer P is separated from solids such as the sheet material S and the polymer P.

[0012] In the water separation treatment process, it is carried out using a water separation agent R that reduces the water retention performance of the polymer P that has absorbed moisture. Specifically, the crushed pieces F, which are the crushed matter of the paper diaper D, are immersed in the treatment liquid T in which the water separation agent R is dissolved in water. The crushed pieces F contain the polymer P in a water-absorbed state. As an example of the water separation agent R, in this embodiment, calcium chloride containing divalent metal ions is used. By reacting the water separation agent R with the polymer P, moisture is separated from the polymer P that has absorbed moisture. The polymer P from which moisture has been separated loses its water absorption performance and becomes an irreversible state where it cannot absorb moisture again. Even if the used paper diaper D contains a polymer P that has not absorbed moisture, the water absorption performance of that polymer P is lost.

[0013] [Configuration of the waste treatment device] As shown in FIG. 1, the waste treatment device 10 includes a charging section 12, a control section 58, a deodorizing device 21, a crushing device 25, a water separation treatment device 38, and a dehydration device 60. The waste treatment device 10 has a vertically long box-shaped housing 13 that is shared by the charging section 12, the crushing device 25, and the water separation treatment device 38. The crushing device 25 is arranged below the charging section 12, the water separation treatment device 38 is arranged below the crushing device 25, and the dehydration device 60 is arranged below the water separation treatment device 38.

[0014] [Configuration of the charging section] The input section 12 is box-shaped with an open bottom. The inside of the input section 12 is an input space 14 into which used disposable diapers D are inserted. In this embodiment 1, the input section 12 is provided with a first input opening 15. The first input opening 15 is formed in the right-side wall of the housing 13. The first input opening 15 is provided with a first lid 16 that can be opened and closed from the outside of the input section 12. The first lid 16 has a central axis 16A that extends horizontally (i.e., in the front-to-back direction) along its lower edge. The central axis 16A is supported by the housing 13. The first lid 16 can rotate outward around the central axis 16A to change its posture between an upright state V and a reclined state L.

[0015] A closing section 22 is provided inside the input section 12 so as to cover the first input opening 15 from the inside. The closing section 22 is made of, for example, a flexible rubber or synthetic resin that is formed in the shape of a flat plate. Multiple slits are formed in the closing section 22 from slightly below the upper end to the lower end. Multiple rectangular sections 22A are formed in the closing section 22, with their upper ends connected to each other by the slits. The closing section 22 is attached to the input section 12 so that its upper end is along the upper edge of the first input opening 15. For example, when a disposable diaper D is inserted into the input section 12 from the first input opening 15, each rectangular section 22A of the closing section 22 is pushed open into the input section 12. Once the disposable diaper D has been inserted into the input section 12, each rectangular section 22A returns to its original position to close the first input opening 15 again.

[0016] The disposable diaper D can be inserted into the input space 14 through the first input opening 15. At this time, the first lid 16 is manually changed from an upright position V to a downed position L, opening the first input opening 15. The user inserts the disposable diaper D into the input section 12 via the first input opening 15 and the closing section 22. At this time, the first lid 16 maintains its position in the downed position L. Therefore, the first lid 16 can prevent moisture etc. adhering to its inner surface (i.e., the surface located inside the input section 12 in the upright position V) from flowing onto the floor. The disposable diaper D is inserted into the input section 12 along the inner surface of the first lid 16. Therefore, when inserting the disposable diaper D through the first input opening 15, the position of the disposable diaper D relative to the crushing device 25 is easily stabilized. After inserting the disposable diaper D, the user manually changes the first lid 16 from the inverted position L to the upright position V, thereby closing the first input opening 15.

[0017] The input section 12 is equipped with an input sensor 20 that detects when a disposable diaper D is inserted into the input space 14 from the first input opening 15. The input sensor 20 transmits a detection signal to the control unit 58 each time a disposable diaper D is inserted. An operation unit is electrically connected to the control unit 58. However, the operation unit is not shown. The user of the waste disposal device 10 can start and stop the operation of the waste disposal device 10 by operating this operation unit.

[0018] As shown in Figure 2, the upper surface of the input section 12 has a first opening 12A, a second opening 12B, and a third opening 12C. The third opening 12C is positioned along the right side edge of the upper surface of the input section 12, closer to the first input opening 15 in the left-right direction. The first opening 12A and the second opening 12B are positioned along the left side edge of the upper surface of the input section 12, furthest from the first input opening 15, with the third opening 12C in between.

[0019] [Configuration of the control unit] The control unit 58 is configured, for example, as a microcomputer. The control unit 58 receives a detection signal from the input sensor 20 and a blockage signal from the detection unit 64. Based on the detection signal from the input sensor 20, the blockage signal from the detection unit 64, and operations on an operation unit (not shown), the control unit 58 can control various operations such as the operation of the intake unit 21D and intake unit 21G, the driving of the crushing motor 29, the water supply operation of the first water supply unit 34 and the second water supply unit 54, the operation of the stirring motor 50, the water release agent R supply operation by the water release agent supply unit 56, the opening and closing operation of the on / off valve 65, and the operation of the dewatering motor 68, which is the drive unit.

[0020] [Configuration of the deodorizing device] The deodorizing device 21 is provided on the upper surface of the input section 12. The deodorizing device 21 has a first deodorizing device 21A and a second deodorizing device 21B. The first deodorizing device 21A and the second deodorizing device 21B are arranged side by side in the left-right direction on the upper surface of the input section 12. Specifically, the second deodorizing device 21B is positioned along the right side edge of the upper surface of the input section 12, closer to the first input opening 15 in the left-right direction. The first deodorizing device 21A is positioned along the left side edge of the upper surface of the input section 12, furthest from the first input opening 15, with the second deodorizing device 21B in between. The first deodorizing device 21A has a case 21C, an air intake section 21D, and a deodorizing unit body 21E. The case 21C is box-shaped with a closed upper end and an open lower end. The case 21C is attached so that its lower end abuts against the upper surface of the input section 12. Case 21C connects the first opening 12A and the second opening 12B of the input section 12.

[0021] For example, a known axial fan is used in the intake section 21D. The intake section 21D draws in air from the bottom and blows it out from the top. The intake section 21D is electrically connected to the control unit 58. The intake section 21D is mounted on the top surface of the input section 12 so as to cover the first opening 12A with its bottom surface. The intake section 21D is located inside the case 21C. The intake section 21D draws in air from the input section 12 through the first opening 12A.

[0022] The deodorizing unit body 21E uses a so-called deodorizing filter, for example, made of a nonwoven fabric to which activated carbon is attached. The deodorizing unit body 21E is positioned so that air blown from the upper surface (i.e., the air-blowing surface) of the intake unit 21D blows onto the front side surface of the deodorizing unit body 21E. Specifically, the deodorizing unit body 21E is positioned within the case 21C so as to partition the side to which the first opening 12A communicates from the side to which the second opening 12B communicates. The intake unit 21D draws air from the input unit 12 from its bottom and blows it from its top toward the deodorizing unit body 21E. The deodorizing unit body 21E deodorizes the air blown from the upper surface of the intake unit 21D. The deodorized air is returned to the input unit 12 through the second opening 12B. The second opening 12B is a circulation port that returns the deodorized air from the first deodorizer 21A back into the input section 12. The first deodorizer 21A primarily deodorizes the air by circulating it in the front-to-back direction in the left-hand region of the input section 12.

[0023] The second deodorizing device 21B comprises a case 21F, an air intake section 21G, and a deodorizing unit body 21H. The case 21F is box-shaped with a closed top and a partially open bottom and rear. The case 21F is mounted so that its bottom surface abuts against the top surface of the input section 12. The rear surface of the case 21F is open. The case 21F is positioned on the top surface of the input section 12 such that its bottom surface overlaps the third opening 12C of the input section 12.

[0024] Similar to the intake section 21D, a known axial fan or the like is used in the intake section 21G. The intake section 21G draws in air from the bottom and blows it out from the top. The intake section 21G is electrically connected to the control unit 58. The intake section 21G is mounted on the top surface of the input section 12 such that the bottom surface of the intake section 21G covers the third opening 12C. The intake section 21G is located inside the case 21F. The intake section 21G draws in air from the input section 12 through the third opening 12C.

[0025] The deodorizing unit body 21H, like the deodorizing unit body 21E, uses a so-called deodorizing filter, which is made of, for example, a nonwoven fabric with activated carbon attached. The deodorizing unit body 21H is positioned to cover the open rear surface of the case 21F. Air blown from the top surface (i.e., the air-blowing surface) of the intake unit 21G is blown onto the front of the deodorizing unit body 21H. The deodorizing unit body 21H discharges the deodorized air to the outside from its rear. At this time, the air Ex discharged to the outside is discharged in a rearward direction, different from the right side where the first inlet 15 is formed. As a result, the deodorized air is not discharged towards the user who is positioned opposite the first inlet 15, so that the waste treatment device 10 can make it difficult for the user to perceive odors. The intake unit 21G sucks air from inside the inlet 12 from its bottom and blows it towards the deodorizing unit body 21H from its top. In other words, the second deodorizing device 21B draws in the odor generated from the disposable diapers D that have been placed into the input section 12 from the right side of the input section 12, deodorizes it, and then discharges the deodorized air to the outside.

[0026] [Configuration of the crushing device] The crushing device 25 is a device for crushing the disposable diapers D, which are the material to be crushed, that are fed into the input section 12. As shown in Figures 1 and 3, the crushing device 25 has a peripheral wall section 26, a pair of left and right crushing members 28, and a first water supply section 34. The peripheral wall section 26 constitutes the housing 13 and is connected to the lower end of the wall section of the input section 12. Inside the crushing device 25, a crushing space 27 is formed, surrounded by the peripheral wall section 26. The crushing space 27 is in communication with the input space 14. The pair of crushing members 28 are housed inside the crushing space 27.

[0027] The pair of crushing members 28 are cylindrical in shape, with their axes oriented in the front-rear direction. Each crushing member 28 has a rotating shaft 30 that is rotationally driven by a crushing motor 29. The driving of the crushing motor 29 is controlled by a control unit 58. The pair of crushing members 28 are arranged side by side with the axes of the rotating shaft 30 at the same height. Multiple shear blades 31 are formed on the outer circumference of each crushing member 28. Each shear blade 31 is disc-shaped and concentric with the rotating shaft 30. The maximum outer diameter of the shear blade 31 is larger than the outer diameter of the rotating shaft 30. The multiple shear blades 31 are arranged at regular intervals in the axial direction of the rotating shaft 30 (see Figure 3). The axial width of one shear blade 31 is the same as, or slightly smaller than, the distance between adjacent shear blades 31.

[0028] The outer surface of each shear blade 31 has a sawtooth shape with multiple protrusions 32 arranged at a constant pitch in the circumferential direction. The direction in which the protrusions 32 protrude is oblique to the radial direction of the shear blade 31. The protrusions 32 protrude forward in the rotational direction of the protrusion 32. Recesses 33 are formed between adjacent protrusions 32 in the circumferential direction on the outer circumference of the shear blade 31. Multiple recesses 33 are arranged at intervals in the circumferential direction on the outer circumference of the shear blade 31. The shape of the protrusions 32 and recesses 33 of one shear blade 31 is symmetrical with the shape of the protrusions 32 and recesses 33 of the other shear blade 31.

[0029] As shown in Figure 3, the multiple shear blades 31 formed on one crushing member 28 and the multiple shear blades 31 formed on the other crushing member 28 are arranged alternately in the axial direction of the rotation axis 30. In the front view shown in Figure 1, which shows the waste treatment device 10 from the front, the rotation direction of one crushing member 28 and the rotation direction of the other crushing member 28 are opposite to each other. In the region where the shear blades 31 of one and the shear blades 31 of the other overlap in the axial direction, both the shear blades 31 of one and the shear blades 31 of the other are displaced downward as the crushing member 28 rotates.

[0030] Between adjacent shear blades 31 in the axial direction, there is a minimum necessary clearance that allows the crushing members 28 to rotate smoothly without interfering with each other, and that prevents crushed pieces F of the disposable diaper D from getting caught between the shear blades 31. The clearance between the shear blades 31 is, for example, 40 μm or more. Between the outer circumference of the shear blade 31 of one crushing member 28 and the outer surface of the rotating shaft 30 of the other crushing member 28, there is a minimum necessary clearance that does not hinder the rotation of both crushing members 28. The clearance between the shear blade 31 and the rotating shaft 30 is, for example, 100 μm or more.

[0031] Of the shear blades 31, the portion opposite to the portion that is alternately arranged in the axial direction is displaced upward as the crushing member 28 rotates. The portion of the shear blades 31 that moves upward is positioned to follow the inner surface of the peripheral wall portion 26. Between the shear blades 31 and the peripheral wall portion 26, there is the minimum necessary clearance that allows the shear blades 31 to rotate smoothly without interfering with the peripheral wall portion 26, and that prevents the crushed pieces F of the disposable diaper D from getting trapped between the shear blades 31 and the peripheral wall portion 26. The clearance between the shear blades 31 and the peripheral wall portion 26 is, for example, 100 μm or more.

[0032] The maximum outer diameter of one crushing member 28 and the maximum outer diameter of the other crushing member 28 are the same. The maximum outer diameter of the crushing member 28 is 120 mm, and the rotational speed of the crushing member 28 is 9 rpm. Therefore, the peripheral speed of the outer circumference of the crushing member 28, i.e., the shear blade 31, is 0.057 m / s. Preferably, the peripheral speed of the outer circumference of the crushing member 28, i.e., the shear blade 31, is 0.1 m / s or less. The width dimension of one shear blade 31, i.e., the dimension in the axial direction of the rotation axis 30, is preferably 6 mm or more and 30 mm or less, and more preferably 10 mm or more and 12 mm or less. Preferably, the width dimension of the shear blade 31 is larger than the particle size of the polymer P in its water-absorbed state, which is 4 mm. When the disposable diaper D is crushed in the crushing device 25, it becomes crushed pieces F. The crushed fragments F include a polymer P in a water-absorbing state, and strip-shaped crushed fragments B that have the same width dimension as the shearing blade 31 (i.e., a predetermined width dimension) and are in the shape of a strip.

[0033] As shown in Figure 1, the first water supply unit 34 is positioned above the crushing member 28 within the peripheral wall portion 26. Water is discharged into the crushing space 27 from the crushing space nozzle 35 of the first water supply unit 34. The water discharged from the crushing space nozzle 35 pours down onto the crushing member 28 from above. The water that pours onto the crushing member 28 flows down below the crushing member 28, passing through the gaps between the shearing blades 31, the gap between the shearing blades 31 and the rotating shaft 30, and the gap between the shearing blades 31 and the peripheral wall portion 26. The water supply operation of the first water supply unit 34 is controlled by the control unit 58.

[0034] [Configuration of the water release treatment device] As shown in Figure 1, the water release treatment device 38 comprises a treatment tank 39, a stirring member 48, a second water supply unit 54, and a water release agent supply unit 56. The treatment tank 39 is box-shaped, and the right-hand portion of its upper surface is open. The interior of the treatment tank 39 is a treatment space for performing water release treatment. The open right-hand portion of the upper surface of the treatment tank 39 is connected to the lower end of the peripheral wall 26 of the crushing device 25. The crushing space 27 and the space inside the treatment tank 39 are in vertical communication.

[0035] As shown in Figures 4 and 5, the bottom surface 41 of the processing tank 39 is composed of a first inclined surface 42, which is a flat surface, and a second inclined surface 43, which is also a flat surface. The bottom surface 41 of the processing tank 39 is bent in a valley shape at the boundary line 44 between the first inclined surface 42 and the second inclined surface 43. The first inclined surface 42 constitutes the front region of the bottom surface 41. The first inclined surface 42 is located below the opening region of the upper surface of the processing tank 39, that is, below the pair of crushing members 28. The second inclined surface 43 constitutes the rear region of the bottom surface 41. The second inclined surface 43 is located in a region that is set back from the pair of crushing members 28.

[0036] As shown in Figure 5, the lower edges of the first inclined surface 42 and the lower edges of the second inclined surface 43 in the left-right direction are connected at an obtuse angle. The first inclined surface 42 is inclined downward toward the rear and downward toward the left. The second inclined surface 43 is inclined downward toward the front and downward toward the left. The boundary line 44 between the first inclined surface 42 and the second inclined surface 43 is inclined downward toward the discharge port 47, which will be described later. The front-to-back dimension of the first inclined surface 42 is greater than the front-to-back dimension of the second inclined surface 43. In a side view, the inclination angle β of the second inclined surface 43 with respect to the horizontal direction H is greater than the inclination angle α of the first inclined surface 42 with respect to the horizontal direction H. The inclination angle α of the first inclined surface 42 is 15°. The inclination angle β of the second inclined surface 43 is 45° or less.

[0037] A circular discharge port 47 is provided on the left side wall 46, which is a side wall constituting the processing tank 39. As shown in Figure 1, the upstream end of the discharge channel 47A is connected to the discharge port 47. The downstream end of the discharge channel 47A is connected to the upper end of the inlet 62 of the dewatering device 60, which will be described later. The discharge channel 47A has a downward slope from the upstream end to the downstream end throughout its entire range. The discharge channel 47A extends with an inclination downward as it moves away from the discharge port 47. As shown in Figure 6, the inclination angle γ of the first central axis L1 above the discharge channel 47A with respect to the horizontal direction H is approximately 15 degrees. Specifically, the first central axis L1 is defined as a straight line connecting the center Ce1 of the discharge port 47 and the center Ce2 at the downstream end of the discharge channel 47A, which extends linearly downward from the discharge port 47. An on-off valve 65 for opening and closing the discharge channel 47A is provided in the middle of the discharge channel 47A. For example, an electric ball valve is used as the on / off valve 65.

[0038] The on-off valve 65 opens after the water separation process is completed in the processing tank 39. The crushed fragments F, polymer P, and processing liquid T in the processing tank 39 are then discharged from the discharge port 47 to the outside of the processing tank 39 by their own weight and the water pressure of the processing liquid T. They flow downstream through the discharge passage 47A and are sent to the inlet 62 of the dewatering device 60, which will be described later. When the on-off valve 65 closes, the crushed fragments F and processing liquid T in the processing tank 39 do not flow down to the dewatering device 60 but remain in the processing tank 39. The opening and closing operation of the on-off valve 65 is controlled by the control unit 58.

[0039] The crushed fragments F and strip-shaped crushed fragments B include lightweight fragments of resin material and other materials from the sheet material S that have a lower density than water. The height dimension of the opening area of ​​the discharge port 47, i.e., the diameter dimension of the discharge port 47, is 50 mm or more. This dimension setting is based on the assumption that the maximum width dimension of the crushed fragments F sheared by the shearing blade 31 is approximately 30 mm.

[0040] The discharge port 47 opens to the right toward the inside of the treatment tank 39 and is located at the lowest point of the bottom surface 41. Specifically, the discharge port 47 is located at the lower end of the left edge of the first inclined surface 42 and the second inclined surface 43, and is located at a position corresponding to the boundary line 44 in the front-rear direction (see Figure 4). Therefore, the bottom surface 41 of the treatment tank 39 is inclined downward toward the discharge port 47.

[0041] The lowest point of the discharge port 47 is located at a height close to the lowest point of the bottom surface 41 of the processing tank 39. The maximum depth of the processing tank 39 is the height dimension from the lowest point (i.e., the left end) of the boundary line 44 on the bottom surface 41 of the processing tank 39 to the upper end of the processing tank 39 (i.e., the lower end of the crushing device 25) (see Figure 5). The maximum depth of the processing tank 39 is within three times the height from the bottom surface 41 of the processing tank 39 to the highest point of the discharge port 47. This dimension setting makes it possible to keep the water level of the processing liquid T stored in the processing tank 39 relatively low and to secure a large area of ​​the liquid surface Ls of the processing liquid T. In this embodiment 1, the left-right dimension and front-back dimension of the processing tank 39 are larger than the maximum depth dimension of the processing tank 39.

[0042] A stirring member 48 is provided on the bottom surface 41. As shown in Figure 4, in a top view of the water release treatment device 38, the stirring member 48 is positioned only in the area of ​​the bottom surface 41 corresponding to the first inclined surface 42. In the front-rear direction, the stirring member 48 is positioned towards the rear of the center of the first inclined surface 42, that is, towards the side closer to the discharge port 47 and the boundary line 44. In the left-right direction, the stirring member 48 is positioned towards the left of the center of the first inclined surface 42, that is, towards the side closer to the discharge port 47. The stirring member 48 is rotationally driven by a stirring motor 50 having a vertical drive shaft 49 (see Figure 1).

[0043] The stirring member 48 has a disc-shaped main body 51 concentric with the drive shaft 49 and a plurality of ribs 52 that rotate integrally with the main body 51. As shown in Figure 6, the main body 51 is parallel to the first inclined surface 42. There is a clearance between the lower surface of the main body 51 and the first inclined surface 42 that allows for smooth rotation of the stirring member 48 and prevents crushed pieces F of the disposable diaper D from getting caught. This clearance between the stirring member 48 and the first inclined surface 42 is approximately 10 mm. The plurality of ribs 52 protrude from the surface of the main body 51 and extend radially from the rotation center of the main body 51. The plurality of ribs 52 are arranged radially on the upper surface of the main body 51 (see Figure 4). The stirring member 48 is rotatably installed in the processing tank 39.

[0044] The drive of the stirring motor 50 is controlled by the control unit 58. During the water release treatment, the stirring member 48 is rotated alternately in the forward direction (one direction) and the reverse direction (other direction) by the control unit 58. The forward direction is the counterclockwise direction in Figure 4, and the reverse direction is the clockwise direction in Figure 4. After the water release treatment, the polymer P and the crushed fragments F containing the strip-shaped crushed fragments B, and the treatment liquid T are discharged from the discharge port 47. As shown in Figure 4, in a plan view, the streamline 47L of the discharge flow at the discharge port 47 is perpendicular to the left wall portion 46 where the discharge port 47 is formed, and parallel to the boundary line 44. Among the tangents that are in contact with the outer edge of the stirring member 48, the tangent perpendicular to the left wall portion 46 is parallel to and close to the streamline 47L of the discharge flow. In other words, among the tangents that touch the outer edge of the stirring member 48, the discharge port 47 lies on the extension of the tangent parallel to the boundary line 44. Therefore, the streamlines 48L of the flow generated by the rotation of the stirring member 48 during discharge, which are directed toward the discharge port 47, are parallel to and close to the streamlines 47L of the discharge flow at the discharge port 47.

[0045] During the water release process, the rotation angle of the stirring member 48 in the forward direction is 60°. During the water release process, the rotation angle of the stirring member 48 in the reverse direction is 45°, which is smaller than the rotation angle in the forward direction. In both forward and reverse rotations, it is preferable that the rotation angle is 10° or more and 120° or less. The outer diameter of the stirring member 48 is 120 mm. The time required for one rotation in the forward direction is 0.3 seconds, and the time required for one rotation in the reverse direction is 0.2 seconds. The peripheral speed of the outer circumference of the stirring member 48 is 200 mm / s. The peripheral speed of the outer circumference of the stirring member 48 during the water release process can be adjusted within the range of 100 to 500 mm / s. After the water release treatment is completed, the peripheral speed of the outer circumference of the stirring member 48 is adjusted to 600 mm / s or more from the time water is supplied to the treatment tank 39 until the crushed pieces F and treatment liquid T in the treatment tank 39 are discharged and the solid material of the crushed pieces F is recovered from the dewatering device 60.

[0046] The second water supply unit 54 has a first nozzle 55A and a second nozzle 55B attached to the treatment tank 39. The first nozzle 55A and the second nozzle 55B face into the treatment tank 39. The first nozzle 55A and the second nozzle 55B are provided on the right wall portion 53 which rises from the bottom surface 41 opposite the left wall portion 46. The first nozzle 55A is positioned to discharge water toward the stirring member 48. The first nozzle 55A discharges water in a fan shape so as to spread horizontally (i.e., in the front-to-back direction).

[0047] The second nozzle 55B is positioned to discharge water into the outlet 47. Specifically, the second nozzle 55B is attached to the right wall portion 53 which is directly opposite the left wall portion 46 where the outlet 47 is formed. As shown in Figures 5 and 6, the second nozzle 55B is positioned above the outlet 47. As shown in Figure 7, the second nozzle 55B has a plurality of discharge ports 55C. Each discharge port 55C is circular in shape. In Embodiment 1, the diameter of each discharge port 55C is, for example, 1 mm. The plurality of discharge ports 55C are arranged at equal intervals on an imaginary circumference C. The central axes of each discharge port 55 are parallel to each other. In Embodiment 1, the second nozzle 55B has eight discharge ports 55C. Each discharge port 55C is parallel to each other and discharges water in a straight line. In other words, the second nozzle 55B is a so-called direct-injection nozzle. In the water discharged from each outlet 55C in the discharge direction Vo, the cross-section perpendicular to the discharge direction Vo at a position at any distance from each outlet 55C is the discharge region Sa1. It can be defined that there are multiple discharge regions Sa1 lined up at arbitrary distances from each outlet 55C in the discharge direction Vo. Here, the straight line passing through the center Ce3 of each of the multiple discharge regions Sa1 lined up from each outlet 55C in the discharge direction Vo is defined as the second central axis L2.

[0048] As shown in Figure 6, the second nozzle 55B discharges water from each discharge port 55C at an angle downward toward the outlet 47. The discharge direction Vo of each discharge port 55C is toward the lower inner edge of the outlet 47. For example, the inclination angle δ of the second central axis L2 of the discharge port 55C with respect to the horizontal direction H is approximately 30 degrees. The inclination angle δ (30 degrees) of the discharge direction Vo (second central axis L2) of the discharge port 55C with respect to the horizontal direction H is greater than the inclination angle γ (15 degrees) of the first central axis L1 of the discharge passage 47A with respect to the horizontal direction H. The second central axis L2 intersects the first central axis L1 at an aerial point Pf, which is a predetermined point in the discharge passage 47A within the treatment tank 39, and passes below the first central axis L1 between the aerial point Pf and the outlet 47. The discharge directions Vo of each discharge port 55C are parallel to each other and are set to point downward from the center Ce1 of the discharge port 47 (in Embodiment 1, to the lower end of the discharge port 47) (see the arrow parallel to the second central axis L2 in Figure 6).

[0049] With the crushed fragments F, polymer P, and processing liquid T contained in the processing tank 39, the second nozzle 55B is positioned above the liquid level Ls. The water discharged from the discharge port 55C travels parallel to the second central axis L2 above the liquid level Ls of the processing liquid T. Then, below the liquid level Ls of the processing liquid T (i.e., within the processing liquid T), the water discharged from each discharge port 55C deviates upward from the second central axis L2, entraining the crushed fragments F as it travels through the processing liquid T, its flow gradually widening, passing around the center Ce1 of the discharge port 47 and flowing into the discharge passage 47A (see the gradually widening arrow in Figure 6). When the discharge port 47 is viewed from the front (right), the water W discharged from each discharge port 55C flows into the discharge port 47 along the inner edge of the discharge port 47 and at equal intervals in a concentric circle with respect to the center Ce1 of the discharge port 47 (see Figure 8). In this way, each discharge port 55C discharges water toward the discharge port 47 in such a manner that it pushes the crushed pieces F in the processing tank 39 into the discharge port 47.

[0050] The first discharge area A1 (see Figure 4) from which the first nozzle 55A discharges water is wider than the second discharge area A2 (see Figure 5) from which the second nozzle 55B discharges water when the processing tank 39 is not filled with processing liquid T and crushed pieces F. The discharge and stopping of water from the first nozzle 55A and the second nozzle 55B are controlled by the control unit 58.

[0051] As shown in Figure 1, a water-removing agent supply unit 56 is attached to the processing tank 39. The water-removing agent supply unit 56 supplies a predetermined amount of the water-removing agent R into the processing tank 39. The supply operation and amount of the water-removing agent R are controlled by the control unit 58.

[0052] [Configuration of the dehydration device] The dewatering device 60 is a screw press dewatering machine used in the so-called waste treatment device 10. The dewatering device 60 has an inlet 62, a detection unit 64, a dewatering machine 61, an outlet 63, and a water collection unit 69. The inlet 62 is cylindrical, and the downstream end of the discharge passage 47A is connected to its upper end. The crushed pieces F and treatment liquid T from the treatment tank 39 are transferred into the dewatering machine 61 by passing through the outlet 47, the discharge passage 47A, the on / off valve 65, and the inlet 62. The inlet 62 is in communication with the outlet 47 of the treatment tank 39 via the discharge passage 47A. The crushed pieces F flow into the inlet 62.

[0053] The detection unit 64 can be, for example, a known capacitance sensor or a laser sensor. The detection unit 64 is mounted at a predetermined height in the inlet 62, facing the inside of the inlet 62. Preferably, the height at which the detection unit 64 is mounted in the inlet 62 is set to a height that matches the amount of crushed fragments F that can clear the blockage. In this embodiment, the detection unit 64 is mounted at a higher height in the inlet 62. The detection unit 64 detects a blockage state, which is a non-conveying state, when the crushed fragments F have accumulated up to the position where the detection unit 64 is mounted. For example, crushed fragments F and processing liquid T flow into the inlet 62, and the detection unit 64 facing the inside of the inlet 62 detects the crushed fragments F and processing liquid T. If there is no blockage in the dewatering machine 61, the crushed pieces F and processing liquid T are dewatered as the dewatering machine 61 is operated, reducing the amount of crushed pieces F and processing liquid T in the inlet 62, and the detection unit 64 facing the inlet 62 will no longer detect the crushed pieces F and processing liquid T within a predetermined time. On the other hand, if there is a blockage in the dewatering machine 61, the crushed pieces F and processing liquid T are not dewatered even when the dewatering machine 61 is operated, so the amount of crushed pieces F and processing liquid T in the inlet 62 does not decrease, and the detection unit 64 facing the inlet 62 continues to detect the crushed pieces F and processing liquid T even after a predetermined time has elapsed, and the control unit 58 determines that there is a blockage (non-conveying state).

[0054] The dewatering machine 61 is connected to the lower end of the inlet 62. Inside the dewatering machine 61, as shown in Figure 9, a screen section 66 and a screw 67 are housed. The screen section 66 is cylindrical with its axis oriented in the left-right direction. The screen section 66 has, for example, multiple water passages extending long in the axial direction that penetrate through it (not shown). The width dimension of the water passages (width dimension in the direction perpendicular to the axial direction) is, for example, 300 μm. It is desirable that the width dimension of these water passages is smaller than the particle size of the polymer P in the dehydrated state after the water has been separated from the water-absorbing state. The internal space of the screen section 66 is a transfer space 66S for transferring the crushed pieces F. The upstream end F1 of the transfer space 66S is connected to the lower end of the inlet 62, and the downstream end F2 of the transfer space 66S is connected to the upper end of the outlet 63.

[0055] The screw 67 has a shaft portion 67A and screw blades 67B that protrude spirally from the outer circumference of the shaft portion 67A. For example, the spacing between the screw blades 67B in the axial direction narrows as it approaches the downstream end F2 (see Figure 9). Also, the shaft diameter of the shaft portion 67A increases as it approaches the downstream end F2 (see Figure 9). Furthermore, the cross-sectional area perpendicular to the axis of the transfer space 66S decreases as it approaches the downstream end F2 (not shown). The shaft portion 67A and the screw blades 67B are arranged in the inlet portion 62 and the screen portion 66, and are rotationally driven by the dewatering motor 68, which is the drive unit. The screw blades 67B extend in the direction of the central axis of the screen portion 66. A gap is provided around the entire circumference between the outer edge of the screw blades 67B located inside the screen portion 66 and the inner surface 66A of the screen portion 66 (see Figure 11).

[0056] The outer edge of the screw blade 67B has a notch 67C. The notch 67C is formed by cutting out the outer edge of the screw blade 67B in a straight line, with the upstream end F1 of the screen section 66 in between, towards the downstream end F2 of the screen section 66 and towards the inside of the inlet section 62. The notch 67C is formed by cutting the outer edge of the screw blade 67B in a straight line (see Figure 11).

[0057] As shown in Figure 10, when the dewatering machine 61 is viewed from above, the center M of the notch 67C in the helical direction Sd (hereinafter also simply referred to as the center M of the notch 67C) coincides with the upstream end F1 of the screen section 66. The right side of the center M of the notch 67C is located within the screen section 66. Within the screen section 66, the dimension D from the center M of the notch 67C in the helical direction Sd to the end of the notch 67C (the end on the downstream end F2 side) is preferably within three times the width dimension of the strip-shaped crushed piece B.

[0058] Within the screen portion 66, the distance Da between the edge of the notch 67C and the inner circumferential surface 66A of the screen portion 66 decreases toward the downstream end F2 (the far side of the page in Figure 11) in the helical direction Sd (see Figures 10, 11, 12, and 13). Specifically, the distance Da between the edge of the notch 67C and the inner circumferential surface 66A of the screen portion 66 on the downstream end F2 side of the helical direction Sd (see Figure 12) is narrower than the distance Da between the edge of the notch 67C and the inner circumferential surface 66A of the screen portion 66 on the side away from the downstream end F2 in the helical direction Sd (see Figure 13). In Figure 11, the screw blade 67B is positioned such that the straight line connecting the center M of the notch 67C and the center of the shaft portion 67A is parallel to the upstream end F1. The screw blades 67B extend counterclockwise from the center M of the notch 67C toward the downstream end F2 (towards the back of the paper). The screw blades 67B extend clockwise from the center M of the notch 67C toward the inlet 62 (towards the front of the paper). The distance Da between the notch 67C and the inner circumferential surface 66A of the screen 66 is largest at the center M of the notch 67C and gradually decreases toward both ends of the notch 67C in the helical direction Sd (see Figure 11).

[0059] The operation of the dewatering motor 68 is controlled by the control unit 58. The control unit 58 performs conveyance control and rotation control, which is a blockage clearing control. Conveyance control is a control that operates the dewatering motor 68 so that the screw 67, which is equipped with screw blades 67B, is continuously rotated in the forward rotation direction Fd. Blockage clearing control is a control that operates the dewatering motor 68 so that the screw 67, which is equipped with screw blades 67B, is repeatedly switched between rotation in the reverse rotation direction Rd and rotation in the forward rotation direction Fd. In blockage clearing control, the control unit 58 controls the dewatering motor 68 (drive unit) so that the rotation angle in the reverse rotation direction Rd is less than the rotation angle in the forward rotation direction Fd.

[0060] When the screw 67 rotates in the forward rotation direction Fd, the crushed pieces F and processing liquid T introduced into the inlet 62 are carried from the inlet 62 into the transfer space 66S by the screw blades 67B. The crushed pieces F and processing liquid T that have entered the transfer space 66S are then transferred by the screw blades 67B toward the outlet 63. At this time, the crushed pieces F and processing liquid T are pressed to the rightward direction by the surface of the screw blades 67B facing the downstream end F2 (right side), and are transferred toward the outlet 63 (see Figure 16). The crushed pieces F that do not pass through the water passages of the screen section 66 are carried by the screw blades 67B of the screw 67 to the downstream end F2 of the transfer space 66S, fall through the outlet 63, and are collected from the recovery port 71. The processing liquid T passes through the water passages of the screen section 66 and flows out of the screen section 66 while being transferred toward the outlet 63. When the strip-shaped fragments B are transported while straddling the screw blades 67B, the gap between the inner surface 66A of the screen section 66 and the screw blades 67B at the upstream end F1 narrows rapidly, the strip-shaped fragments B are rapidly pressurized, stick to the screw blades 67B and rotate together, and cease to be transported. Furthermore, the strip-shaped fragments B become entangled with other strip-shaped fragments B, forming a large mass that rotates together and causes clogging.

[0061] In the blockage clearing control, when the screw blade 67B rotates in the reverse direction Rd, the screw blade 67B detaches from the fragment F that is in contact with the downstream end F2 side (right side) of the screw blade 67B, moving to the left. The strip-shaped fragment B is rapidly pressurized, and the clumped portion moves without rotating together, reaching the notch 67C. The strip-shaped fragment B that caused the blockage detaches from the screw blade 67B, clearing the blockage (see Figure 15).

[0062] As shown in Figure 9, the outlet section 63 is located at the right end of the dewatering machine 61 and has a cylindrical shape that protrudes downward from the dewatering machine 61. A recovery port 71 that opens downward is formed at the lower end of the outlet section 63.

[0063] The water collection section 69 is formed in the area of ​​the lower surface of the dewatering machine 61 that corresponds to the screen section 66. The water collection section 69 opens upward toward the transfer space 66S over the entire range from the upstream end F1 to the downstream end F2 of the transfer space 66S. A drain port 70 is formed at the lowest position of the water collection section 69. During the process in which the screw 67 transfers the crushed pieces F and the processed liquid T in the transfer space 66S, the waste liquid containing the processed liquid T flows out of the transfer space 66S through the water passage holes of the screen section 66. The waste liquid that flows out of the transfer space 66S is collected in the water collection section 69 and discharged to the sewer or the like through the drain port 70 via a drain pipe (not shown).

[0064] The axis of the screw 67 is the same as the axis of the screen section 66 and is parallel to the transport direction of the screw 67. As shown in Figure 1, in a side view, the axis of the screw 67 is inclined such that the downstream end in the transport direction is higher than the upstream end in the transport direction. The direction in which the screw 67 transports the crushed pieces F within the transport space 66S is such that it lifts the crushed pieces F against gravity.

[0065] The control unit 58 controls the timing of the start of the water separation process according to the amount of paper diapers D put into the input unit 12 and the elapsed time after the paper diapers D have been put in. The control unit 58 controls the water separation process time in the water separation processing device 38, the timing of transferring the crushed pieces F and processing liquid T after water separation to the dewatering device 60, and the rotation direction of the screw 67 of the dewatering device 60 (transport control, blockage clearing control).

[0066] [Regarding the control of the crushing process by the control unit] A used disposable diaper D is placed into the input space 14. When the control unit 58 detects that the used disposable diaper D has been placed into the input space 14, it starts the operation of the deodorizing device 21. The control unit 58 then starts the crushing motor 29. Immediately after being placed in, the disposable diaper D is crushed by a pair of shearing blades 31, and falls into the processing tank 39 as crushed pieces F, which include strip-shaped crushed pieces B with a predetermined width. The crushed pieces F contain polymer P in a water-absorbing state. Thus, the processing tank 39 contains crushed pieces F of disposable diaper D containing polymer P in a water-absorbing state.

[0067] The crushing member 28 may rotate continuously, or it may rotate only while crushing the disposable diaper D. The amount of water supplied from the first water supply unit 34 is only the amount necessary for crushing and releasing water from one disposable diaper D. The maximum particle size of the water-absorbed polymer P is approximately 4 mm, while the width dimension of the shear blades 31 of the crushing member 28 is 6 mm or more, so there is no risk of the water-absorbed polymer P being sheared by the shear blades 31. The peripheral speed of the outer circumference of the shear blades 31 is low, at 0.1 m / s or less, so the crushing of the water-absorbed polymer P can also be avoided by setting this speed. The width dimension of the shear blades 31 is 30 mm or less, so the sheet material S of the disposable diaper D can be finely sheared into strips. The crushed fragments F are caught on the projections 32 on the outer circumference of the shear blades 31 and fitted into the recesses 33, so they can be reliably dropped into the processing tank 39 below the crushing member 28.

[0068] [Regarding the control of the water separation and dewatering processes by the control unit] The control of the water release and dewatering processes by the control unit 58 will be explained with reference to the flowcharts in Figures 16 and 17. After the crushing process is performed, the control unit 58 starts the rotation of the stirring member 48 (step S20). Next, the water release agent R, which consists of calcium chloride, is introduced into the processing tank 39, and the water supply from the first water supply unit 34 is started (step S21). It is preferable that the introduction of the water release agent R and the water supply from the first water supply unit 34 are started simultaneously. The introduction of the water release agent R and the water supply from the first water supply unit 34 may be performed with a time difference. The water supplied from the first water supply unit 34 washes the crushing member 28 and flows down into the processing tank 39. After a predetermined amount of water has been supplied, the water supply from the first water supply unit 34 is stopped (step S22).

[0069] The amount of water synergistic agent R added is controlled by the control unit 58 to be an appropriate amount based on the number, i.e., mass, of the disposable diapers D that are to be subjected to the water synergistic treatment. When the water synergistic agent R dissolves in the water supplied to the treatment tank 39, it becomes a treatment liquid T for water synergistic treatment. In this embodiment 1, the water synergistic agent R and water were supplied to the treatment tank 39 separately. Alternatively, a treatment liquid T in which the water synergistic agent R has been dissolved in water in advance may be supplied to the treatment tank 39. Water synergistic treatment is a process in which the water retention capacity of the polymer P of the crushed pieces F immersed in the treatment liquid T is reduced by the water synergistic agent R in the synergistic liquid, and water is separated from the polymer P. The reaction rate of water synergistic treatment becomes faster as the amount of water synergistic agent R increases, i.e., as the concentration of the treatment liquid T increases.

[0070] The stirring member 48 alternately rotates in the forward direction, which is the counterclockwise direction in Figure 4, and in the reverse direction, which is the clockwise direction. Therefore, even if the crushed pieces F are piled up on the stirring member 48 when it starts to rotate, the pile of crushed pieces F is broken down as the stirring member 48 rotates in both forward and reverse directions, and the crushed pieces F are diffused into the processing liquid T. The peripheral speed of the outer circumference of the stirring member 48 is slower than 500 mm / s, so the crushed pieces F and the processing liquid T are not thrown out radially.

[0071] The stirring member 48 rotates at a rate of 60° in the forward direction, while its rotation angle in the reverse direction is 45°. Due to this difference in forward and reverse rotation angles, the stirring member 48 rotates intermittently in the forward direction. This intermittent forward rotation of the stirring member 48 causes the treatment liquid T and crushed pieces F to flow in a swirling, rectified manner in the areas of the treatment tank 39 far from the stirring member 48. Near the stirring member 48, turbulence occurs, causing the treatment liquid T and crushed pieces F to move rapidly. These movements cause the water-removing agent R to come into contact with the polymer P, promoting water-removal.

[0072] The control unit 58 determines whether a predetermined water-separation time has elapsed since the start of the water-separation process (step S23). When the predetermined water-separation time has elapsed, the water-separation process is terminated. The predetermined water-separation time is shorter than the time required for water to be completely separated from the polymer P. The particle size and mass of the polymer P at the time the water-separation time has elapsed are greater than the particle size and mass of the polymer P when water-separation is completely performed.

[0073] When the water release process is complete, the control unit 58 starts supplying water from the first water supply unit 34 and the second water supply unit 54 to the treatment tank 39 (step S24). This water supply reduces the concentration of the treatment liquid T in the treatment tank 39, so the water release process by the water release agent R stops. During this time, the polymer P is in an irreversible state.

[0074] When the water supply to the treatment tank 39 has progressed to a certain extent, the water supply to the treatment tank 39 is stopped (step S25). At this time, the water level in the treatment tank 39 is above the discharge port 47 and below the first nozzle 55A and the second nozzle 55B. After this, the control unit 58 rotates the stirring member 48 in the forward direction to start the rotation of the screw 67 (step S26), and then opens the on-off valve 65 (step S27). At this time, the control unit 58 starts executing transport control to rotate the screw 67 in the forward rotation direction Fd.

[0075] When the on-off valve 65 is opened, the processing liquid T and crushed pieces F in the processing tank 39 are discharged from the outlet 47. In the initial stages of the process of the processing liquid T and crushed pieces F being discharged from the outlet 47, the stirring member 48 continues to rotate in the forward direction. The viscosity of the processing liquid T is reduced by the water supplied from the first water supply section 34 and the second water supply section 54, so the flow resistance is small and discharge from the outlet 47 is smooth. The direction of the discharge flow at the outlet 47 is parallel to the boundary line 44 between the first inclined surface 42 and the second inclined surface 43. Of the vortex flow generated by the stirring member 48, a portion of the flow in the region in contact with the boundary line 44 flows parallel to the boundary line 44 towards the outlet 47. Therefore, the flow velocity of the discharge flow at the outlet 47 is increased.

[0076] As the on-off valve 65 opens, water is temporarily discharged from the first nozzle 55A and the second nozzle 55B of the second water supply unit 54 (step S28). This discharge of water increases the flow velocity of the discharge flow from the outlet 47. At this time, as shown in Figure 6, the water discharged from the second nozzle 55B strikes the liquid surface Ls and proceeds through the processing liquid T toward the outlet 47. When the water discharged from the second nozzle 55B strikes the liquid surface Ls, its direction of travel changes to be slightly upward with respect to the second central axis L2 and proceeds through the processing liquid T, gradually widening the outer diameter of the flow while entraining the crushed fragments F (see the gradually widening arrow in Figure 6). In this way, the water discharged from each outlet 55C of the second nozzle 55B that reaches the outlet 47 flows into the outlet 47 along the inner edge of the outlet 47. In detail, the water W discharged from each discharge port 55C flows into the discharge port 47 at equal intervals in a concentric circle with respect to the center Ce1 of the discharge port 47 (see Figures 7 and 8). In this way, the processing liquid T and crushed pieces F are pushed into the discharge port 47 by the water W discharged from the second nozzle 55B and are properly discharged from the processing tank 39.

[0077] The first nozzle 55A begins discharging water when the crushed pieces F begin to be discharged from the discharge port 47. The first nozzle 55A discharges water in a fan shape. As a result, the processing liquid T and crushed pieces F in the processing tank 39 are stirred in a vertical rotation, mixing evenly and making it easier to discharge from the discharge port 47. Specifically, this vertical rotation of the processing liquid T and crushed pieces F occurs when the water discharged from the first nozzle 55A causes the upper part of the processing liquid T and crushed pieces F stored in the processing tank 39 to flow to the left and sink downwards, and then flow to the right along the bottom surface 41 of the processing tank 39 and rise upwards. In other words, the first nozzle 55A discharges water in a way that pushes the crushed pieces F floating on the water surface into the water and diffuses the crushed pieces F in the processing tank 39.

[0078] After the discharge of the processing liquid T and crushed pieces F from the discharge port 47 begins, step S28 is executed for a predetermined time, and then the discharge of water from the first nozzle 55A and the second nozzle 55B is temporarily stopped for a predetermined time (step S29). This reduces the water supply from the second water supply unit 54, thereby saving water.

[0079] Step S29 is executed to close the on-off valve 65 after a predetermined time (Step S30). Step S30 is executed to open the on-off valve 65 after a predetermined time (Step S31). Furthermore, as the discharge of the processed liquid T and crushed pieces F from the discharge port 47 progresses, the operation of the stirring member 48 changes from rotating in the forward direction to rotating alternately in the forward and reverse directions in small increments (Step S32). This shakes off the crushed pieces F accumulated on the upper surface of the stirring member 48. In other words, the stirring member 48 starts rotating in the forward direction and then rotates alternately in both forward and reverse directions. At this time, the rotation angle in the reverse direction of the stirring member 48 is greater than the rotation angle in the forward direction. As a result, the stirring member 48 rotates intermittently in the reverse direction. Furthermore, at this time, the discharge of water from the first nozzle 55A and the second nozzle 55B is resumed (Step S33). As the agitator 48 rotates intermittently in the opposite direction, the water discharged from the first nozzle 55A is evenly distributed over the entire upper surface of the agitator 48. At this time, the crushed fragments F accumulated on the upper surface of the agitator 48 are detached from the upper surface of the agitator 48 and pushed towards the discharge port 47. In other words, the first nozzle 55A discharges water in such a way that it pushes the crushed fragments F towards the discharge port 47. Furthermore, as the discharge of crushed fragments F and processing liquid T from the processing tank 39 progresses and the liquid level Ls in the processing tank 39 decreases until the liquid level Ls reaches the lower end of the discharge port 47, the water discharged from the second nozzle 55B is discharged towards the lower end of the discharge port 47 without being directed upward relative to the second central axis L2 (see the arrow parallel to the second central axis L2 in Figure 6). Thus, when the liquid level Ls in the processing tank 39 decreases, the water discharged from the second nozzle 55B is discharged towards the lower end of the outlet 47, thereby pushing the crushed pieces F, especially those containing polymer P which is denser than water, that have accumulated at the bottom of the processing tank 39 toward the outlet 47.

[0080] After step S33 is performed and a predetermined time has elapsed, the discharge of the processing liquid T and crushed pieces F from the discharge port 47 has progressed, and when there are no more crushed pieces F above the stirring member 48, the discharge of water from the first nozzle 55A and the second nozzle 55B is stopped, and the operation of the stirring member 48 is changed from alternating small rotations in the forward and reverse directions to rotation in the forward direction (step S34). In other words, the first nozzle 55A discharges water until there are no more crushed pieces F above the stirring member 48. The cessation of water discharge from the first nozzle 55A for a predetermined time (before the execution of steps S29 to S33) occurs between the start of the discharge of crushed pieces F from the discharge port 47 and the time when there are no more crushed pieces F above the stirring member 48. The timing of the end of water discharge from the second nozzle 55B may be later than the timing of the end of water discharge from the first nozzle 55A. This ensures that the processing liquid T and crushed pieces F are discharged from the discharge port 47. If the dewatering device 60 is configured to be located separately from the others, delaying the end of water discharge from the second nozzle 55B compared to the end of water discharge from the first nozzle 55A can be expected to flush out the inside of the discharge passage 47A so that the crushed pieces F discharged from the discharge port 47 do not clog the discharge passage 47A. Step S34 is executed and the on / off valve 65 is closed after a predetermined time (step S35).

[0081] The processing liquid T and crushed pieces F discharged from the discharge port 47 are transferred to the dewatering machine 61 through the discharge passage 47A. In step S26, the control unit 58 starts executing transport control and continues rotating the screw 67 in the forward rotation direction Fd. Inside the dewatering machine 61, the strip-shaped crushed pieces B and crushed pieces F containing the processing liquid T are compressed axially by the screw blades 67B of the screw 67, causing moisture to seep out from within the strip-shaped crushed pieces B and F. The seeped-out moisture passes through the water passage holes of the screen section 66 and is discharged from the drain port 70. The crushed pieces F containing polymer P, which have been pushed by the screw 67, are recovered from the recovery port 71.

[0082] Within the screen section 66, there is a concern that some of the polymer P may pass through the water passages of the screen section 66 because it comes into contact with the inner circumferential surface 66A of the screen section 66. However, in the crushing device 25, the peripheral speed of the shear blade 31 is set to a low speed of 0.1 m / s, and the width dimension of the shear blade 31 is set to 6 mm or more, which is larger than the particle size of the polymer P in the water-absorbing state. Therefore, the polymer P in the water-absorbing state is not sheared and falls into the processing tank 39 of the water-separating device 38 as large particles. Furthermore, in the water-separating device 38, the water-separating process is terminated before the water is completely separated from the polymer P, so the particle size of the polymer P is maintained at a certain size. Therefore, there is no risk of the polymer P passing through the water passages of the screen section 66.

[0083] As shown in Figure 14, when the control unit 58 is performing transport control, the strip-shaped crushed piece B may get stuck between the screw blade 67B and the inner circumferential surface 66A of the screen section 66. If the strip-shaped crushed piece B is transported while straddling the screw blade 67B, the gap between the inner circumferential surface 66A of the screen section 66 and the screw blade 67B narrows rapidly at the upstream end F1, causing the strip-shaped crushed piece B to be rapidly pressurized and stick to the screw blade 67B. In this case, because the strip-shaped crushed piece B sticks to the screw blade 67B, the crushed piece F and the strip-shaped crushed piece B rotate together with the screw blade 67B and are not transported to the downstream end F2. Furthermore, the strip-shaped crushed pieces B become entangled with other strip-shaped crushed pieces B, forming a large mass that rotates together with the screw blades 67B. As a result, the processing liquid T and crushed pieces F are not transported from the inlet 62 into the screen section 66 (transfer space 66S), and the processing liquid T and crushed pieces F that flowed from the processing tank 39 into the inlet 62 accumulate in the inlet 62. In such a case, when the detection unit 64 detects the accumulation of processing liquid T and crushed pieces F in the inlet 62, the control unit 58 stops the execution of the transport control and executes the blockage clearing control.

[0084] In the declogging control, the dewatering motor 68 is operated to repeatedly switch the screw 67 between the reverse rotation direction Rd and the forward rotation direction Fd (see Figure 11). When the screw 67 rotates in the reverse rotation direction Rd during the declogging control, as shown in Figure 15, the strip-shaped crushed pieces B that are stuck to the screw blades 67B and the crushed pieces F that have become entangled with other strip-shaped crushed pieces B and formed a large mass are separated from the screw blades 67B by moving to the left. At this time, the strip-shaped fragment B, which is stuck to straddle the screw blade 67B, detaches from the axis of the shaft 67A (towards the foreground of the paper in Figure 15) as it approaches the notch 67C (screw blade 67B), and is pulled to the right by the fragment F located to the right of the notch 67C (downstream end F2 side), moving to the right side of the notch 67C. Then, when the screw 67 rotates in the forward rotation direction Fd, the strip-shaped fragment B that has moved to the right side of the notch 67C is pushed to the right (downstream end F2 side) by the screw blade 67B along with the fragment F, and is conveyed toward the downstream end F2. In this way, the control unit 58 performs a blockage clearing control to detach the strip-shaped fragment B from the screw blade 67B and eliminate the state in which the fragment F rotates together with the screw blade 67B.

[0085] Here, an example of the control in the control unit 58 that switches between transport control and blockage clearing control will be explained with reference to Figure 17, etc. For example, the process shown in Figure 17 is executed in the control unit 58 after closing the on-off valve 65 (after executing step S35). First, after closing the on-off valve 65, the process moves to step S70 to continue the transport control. Next, the process moves to step S71 to determine whether the incoming processed liquid T and crushed pieces F have been transported. If, in step S71, the incoming processed liquid T and crushed pieces F have not yet been transported (No in step S71), the process moves to step S72 to determine whether a blockage signal has been input from the detection unit 64. If, in step S72, it is determined that no blockage signal has been input (No in step S72), the process moves to step S70 to continue the transport control. If it is determined in step S71 that the incoming processing liquid T and crushed pieces F have been removed (Yes in step S71), the process proceeds to step S36 to determine whether the processing of all the processing liquid T and crushed pieces F has been completed.

[0086] In step S72, if it is determined that a blockage signal has been input from the detection unit 64 (Yes in step S72), the process proceeds to step S73 to execute blockage clearing control. While blockage clearing control is being executed, the process repeatedly proceeds to step S72 to determine whether or not a blockage signal has been input from the detection unit 64. Blockage clearing control is repeated until no more blockage signals are input (No in step S72).

[0087] Once all processing liquid T and crushed pieces F have been processed (Yes in step S36), the control unit 58 stops the rotation of the stirring member 48 (step S37), stops the execution of the transport control and blockage clearing control, and stops the rotation of the screw 67 (step S38). The deodorizer 21 also stops operating. With this, the water separation and dewatering processes are completed. If all processing liquid T and crushed pieces F have not been processed in step S36 (No in step S36), the process proceeds to step S31.

[0088] In the waste treatment device 10, the total amount of water discharged from the first water supply unit 34 and the second water supply unit 54 when processing one disposable diaper D can be set to a predetermined amount. For example, in the case of a disposable diaper D containing relatively small amounts of sheet material S, pulp, and polymer P, the total amount of water discharged from the first water supply unit 34 and the second water supply unit 54 can be set to approximately 10 liters. In contrast, in the case of a disposable diaper D containing relatively large amounts of sheet material S, pulp, and polymer P, the total amount of water discharged from the first water supply unit 34 and the second water supply unit 54 can be set to approximately 20 liters.

[0089] According to the embodiment configured as described above, the following effects are achieved.

[0090] The dewatering apparatus 60 of this disclosure comprises an inlet 62 into which crushed pieces F of the material to be processed flow in, a cylindrical screen section 66 whose upstream end is connected to the inlet 62, and screw blades 67B arranged within the inlet 62 and the screen section 66 and extending in the direction of the central axis of the screen section 66. The outer peripheral edge of the screw blades 67B has a notch 67C cut out from the upstream end F1 of the screen section 66 toward the downstream end F2. With this configuration, even if the crushed pieces F become entangled so as to straddle the outer edge of the screw blades 67B, the notch 67C can effectively untangle the crushed pieces F with the screw blades 67B, reducing the opportunity for the crushed pieces F to rotate together with the screw blades 67B, and enabling efficient transport of the crushed pieces F.

[0091] In the dewatering apparatus 60 of this disclosure, the crushed pieces F include strip-shaped crushed pieces B having a predetermined width dimension and being in the shape of a strip, and within the screen section 66, the dimension of the notch 67C in the helical direction Sd along the outer edge of the screw blade 67B is within three times the width dimension of the strip-shaped crushed pieces B. With this configuration, even if the strip-shaped crushed pieces B become clogged on the upstream end F1 side of the screen section 66, the area of ​​clogging in the central axis direction of the screen section 66 will not become large, and the strip-shaped crushed pieces B that are clogged in the screen section 66 will be easier to remove.

[0092] In the dewatering apparatus 60 of this disclosure, the distance Da between the edge of the notch 67C and the inner circumferential surface 66A of the screen portion 66 decreases toward the downstream end F2 in the helical direction Sd. With this configuration, when the screw blade 67B rotates in the reverse rotation direction Rd, the strip-shaped crushed pieces B that are entangled so as to straddle the outer edge of the screw blade 67B do not get caught on the outer edge of the notch 67C and can move by sliding along the outer edge of the notch 67C.

[0093] The dewatering apparatus 60 of this disclosure includes a dewatering motor 68 that drives a screw blade 67B, and a control unit 58 that controls the dewatering motor 68. The control unit 58 performs clogging removal control (rotation control) which repeatedly rotates the screw blade 67B in the reverse rotation direction Rd and the forward rotation direction Fd. With this configuration, the strip-shaped crushed pieces B that are entangled in the screw blade 67B can be peeled off the screw blade 67B and transported efficiently.

[0094] The dewatering device 60 of this disclosure includes a detection unit 64 that detects a non-conveying state in which crushed pieces F are not conveyed from the inlet 62 to the screen 66, and the control unit 58 executes clogging removal control (rotation control) based on the detection unit 64 detecting a non-conveying state. With this configuration, clogging removal control can be performed automatically.

[0095] The detection unit 64 of the dewatering device 60 of this disclosure is mounted at a predetermined height facing the inside of the inlet 62, and detects a non-conveying state when the crushed pieces F accumulate up to the position where the detection unit 64 is mounted. With this configuration, the non-conveying state can be easily identified.

[0096] The control unit 58 of the dewatering device 60 of this disclosure controls the dewatering motor 68 in the blockage removal control (rotation control) such that the rotation angle in the reverse rotation direction Rd is less than the rotation angle in the forward rotation direction Fd. With this configuration, the crushed pieces F can be reliably conveyed while resolving the entanglement of the strip-shaped crushed pieces B with respect to the screw blades 67B.

[0097] This disclosure is not limited to Embodiment 1 described above in the description and drawings, but also includes, for example, the following embodiments of the crushing apparatus of this disclosure in its technical scope.

[0098] (1) In Embodiment 1, the stirring member is provided on the bottom surface of the treatment tank. However, it is not limited to this and may be provided on other surfaces inside the treatment tank. (2) In Embodiment 1, water is discharged from the first nozzle and the second nozzle at the same time. However, the discharge of water from the first nozzle and the second nozzle may be performed at separate timings. (3) Embodiment 1 discloses that the water discharge from the first nozzle is fan-shaped. However, it is not limited to this, and the water discharge may be in a conical shape. Furthermore, multiple second nozzles that discharge water in a straight line may be arranged in a row. (4) In Embodiment 1, calcium chloride is used as the water-removing agent. However, other agents containing Ca or Mg may be used, such as calcium acetate, magnesium chloride, water-soluble alkaline earth metal salts of magnesium nitrate, or citric acid. (5) The water-reinforcing agent may be a solid or a liquid. If the water-reinforcing agent is a liquid, a water-reinforcing agent supply unit is used which includes a water-reinforcing agent storage tank for storing the water-reinforcing agent and a pump for taking the water-reinforcing agent from the water-reinforcing agent storage tank and sending it toward the housing. (6) The number of discharge ports in the nozzle is not limited to Embodiment 1. (7) The arrangement of discharge ports in the nozzle may be changed according to the outer shape of the outlet. For example, if the outer shape of the outlet is rectangular, the nozzle 155 may have discharge ports 155C that discharge water linearly at equal intervals relative to the outlet, as shown in Figure 18. In this case, the shape of each water discharge region Sa2, which is arranged at an arbitrary distance from each discharge port 155C in the discharge direction Vo, is strip-shaped, and the second central axis L2 passes through the center of the linearly arranged discharge ports 155C and through the center Ce4 of each strip-shaped water discharge region Sa2 arranged from each discharge port 155C in the discharge direction Vo. (8) A water level sensor may be used as the detection unit. In this case, the control unit may execute blockage clearing control when the processing liquid accumulated in the inlet comes into contact with the water level sensor, and the control unit may execute transport control when the processing liquid is not in contact with the water level sensor. (9) Unlike Embodiment 1, the discharge direction of more than half of the multiple discharge ports may be directed downward from the center of the outlet. (10) The angle of inclination of the discharge direction of the discharge port with respect to the horizontal direction, and the angle of inclination of the first central axis of the discharge passage with respect to the horizontal direction are not limited to the first embodiment, but are sufficient if the angle of inclination of the discharge direction with respect to the horizontal direction is greater than the angle of inclination of the first central axis of the discharge passage with respect to the horizontal direction. (11) The dewatering apparatus of the present disclosure can also be used as a dewatering machine for a waste treatment apparatus that processes sanitary products that do not contain superabsorbent polymers.

[0099] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is not limited to the embodiments disclosed herein. [Explanation of Symbols]

[0100] 10...Waste treatment device, 58...Control unit, 60...Dewatering device (screw press dewatering machine), 62...Inlet, 64...Detection unit, 66...Screen unit, 67B...Screw blade, 67C...Notch, 68...Dewatering motor (drive unit), B...Strip-shaped crushed piece, Da...Separation dimension, F...Crushed piece, F1...Upstream end of screen unit, F2...Downstream end of screen unit, Fd...Forward rotation direction, Sd...Helical direction, Rd...Reverse rotation direction

Claims

1. An inlet into which crushed pieces of the material to be processed flow in, A cylindrical screen section, the upstream end of which is connected to the inlet section, A screw blade is arranged within the inlet and the screen section, and extends in the direction of the central axis of the screen section. Equipped with, A screw press dewatering machine for use in a waste treatment device, wherein the outer peripheral edge of the screw blade has a notch cut out from the upstream end of the screen portion toward the downstream end.

2. The crushed pieces include strip-shaped crushed pieces having a predetermined width dimension and forming a strip. Within the screen portion, the dimensions of the notch in the helical direction along the outer edge of the screw blade are: A screw press dewatering machine for use in the waste treatment device according to claim 1, wherein the width dimension is within three times the aforementioned width dimension.

3. The screw press dewatering machine for a waste treatment device according to claim 2, wherein, within the screen portion, the distance between the edge of the notch and the inner circumferential surface of the screen portion decreases toward the downstream end in the spiral direction.

4. The drive unit for driving the screw blades, A control unit that controls the drive unit, Equipped with, The control unit performs rotational control to repeatedly rotate the screw blades in the reverse rotation direction and the forward rotation direction, wherein the screw press dewatering machine is used in the waste treatment device according to claim 3.

5. The system includes a detection unit that detects a non-conveying state in which the crushed pieces are not conveyed from the inlet to the screen section. The control unit performs the rotation control based on the detection unit detecting the non-conveying state, wherein the screw press dewatering machine is used in the waste treatment device according to claim 4.

6. The screw press dewatering machine for a waste treatment device according to claim 5, wherein the detection unit is mounted at a predetermined height facing the inside of the inlet, and detects the non-conveying state when the crushed pieces accumulate up to the position where the detection unit is mounted.

7. The control unit controls the drive unit in the rotation control such that the rotation angle in the reverse rotation direction is less than the rotation angle in the forward rotation direction, a screw press dewatering machine for use in a waste treatment device according to claim 4 or claim 5.

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