Method for producing soil

Abstract

To produce soil by utilizing a material which is difficult to be effectively utilized.SOLUTION: A soil manufacturing method includes a generation step of dehydrating a solid-liquid mixture by a filter press device to generate a dehydrated cake, a collection step of collecting a granular material containing at least one of dust and a filler by a dust collector, and a mixing step of mixing the dehydrated cake generated in the generation step and the granular material collected in the collection step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing soil. [Background technology]

[0002] In order to strengthen and stabilize soft ground, there is a method of adding a solidifying agent to the soil, stirring and mixing it, and solidifying it. Cement-based solidifying agents, lime-based solidifying agents, and gypsum-based solidifying agents are known as solidifying agents used in such soil improvement. For example, the solidifying agent for ground improvement described in Patent Document 1 contains cement, blast furnace slag powder, aggregate, and gypsum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-31574 Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing soil solidification materials, securing raw materials becomes an issue. For example, if the materials must be manufactured from scratch and mixed in, or if a lot of chemical processing is required, it will be time-consuming and costly.

[0005] In order to solve at least one of the above-mentioned problems, the present disclosure provides a technology that can produce soil by utilizing materials that are difficult to effectively utilize. [Means for solving the problem]

[0006] A method for producing soil according to the present disclosure includes: a generating step of dewatering the solid-liquid mixture using a filter press device to generate a dewatered cake; a collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the dehydrated cake produced in the producing step with the powder or granular material collected in the collecting step; Includes.

[0007] A method for producing soil according to the present disclosure includes: a collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the powder and granular material collected in the collecting step with lime and gypsum; Includes. [Effects of the Invention]

[0008] The technology disclosed herein can produce soil by utilizing materials that are difficult to effectively utilize. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view conceptually showing a filter press device used in a soil production method according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram conceptually showing an example of a specific embodiment of a part of the filter press apparatus of FIG. [Figure 3] FIG. 3 is an explanatory diagram conceptually illustrating the configuration of a part of the filter press apparatus of FIG. 1 as viewed from above. [Figure 4] FIG. 4 is an explanatory diagram conceptually illustrating the configuration of a portion of the filter press apparatus of FIG. 1 as viewed from the front side. [Figure 5] (A) is an explanatory diagram illustrating one pair of adjacent filter plates in the first holding state as viewed from above, and (B) is an explanatory diagram illustrating the pair of filter plates being separated to allow cake (residue) to fall. [Figure 6] FIG. 6 is an explanatory diagram illustrating a state in which one filter plate and another filter plate are spaced apart in the filter plate structure of the filter press device of FIG. [Figure 7] FIG. 7 is an explanatory diagram illustrating a state in which a solid-liquid mixture flows into one filter plate in the filter plate structure of the filter press device of FIG. 1 while the other filter plates are in close contact with each other. [Figure 8] FIG. 2 is a front view of one filter plate of the filter press apparatus of FIG. 1. [Figure 9] FIG. 9 is a front view illustrating the filter plate of FIG. 8 with the filter cloth omitted. [Figure 10] FIG. 10 is a front view illustrating the configuration of FIG. 9 in which the covering portion is further omitted. [Figure 11] FIG. 11 is a rear view of the filter plate of FIG. [Figure 12] FIG. 12 is a rear view illustrating the filter plate of FIG. 11 with the filter cloth removed. [Figure 13] FIG. 13 is a rear view illustrating the configuration of FIG. 12 with the covering portion further omitted. [Figure 14] FIG. 14 is an enlarged view showing a part of the cross section of the filter plate illustrated in FIGS. [Figure 15] Figure 15(A) is an enlarged view showing the configuration of the covering portion (drainage plate) as viewed from one side, and Figure 15(B) is an enlarged view showing the configuration of the covering portion (drainage plate) as viewed from the other side. [Figure 16] Fig. 16(A) is a cross-sectional schematic diagram conceptually showing the configuration of the drainage board and waterproofing material at the AA cross section of Fig. 15(A). Fig. 16(B) is a cross-sectional schematic diagram conceptually showing the configuration of the drainage board and waterproofing material at the BB cross section of Fig. 15(A). [Figure 17] FIG. 17 is an explanatory diagram conceptually explaining, in an enlarged scale, the configuration of the filter cloth, the drainage plate, the waterproof material, and the plate-like body in the vicinity of the cross section BB in FIG. 15(A). [Figure 18] FIG. 18 is an explanatory diagram illustrating a method for reusing soil using the soil production method according to the first embodiment. [Figure 19] FIG. 19 is a diagram illustrating a second embodiment, which schematically shows a part of a filter plate of the filter press device used in the first embodiment, and is a diagram illustrating a configuration obtained by modifying the configuration of FIG. [Figure 20] FIG. 20 is a diagram schematically showing a part of the filter plate of the filter press device of FIG. 19, and shows a configuration that is a modification of the configuration of FIG. [Figure 21]Figure 21 is a diagram illustrating a drainage plate (covering portion) used in a filter plate of a filter press device according to another embodiment, where (A) is a diagram viewed from one plate surface side, and (B) is a diagram showing a cross section cut along the plate thickness direction. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes exemplary embodiments of the present disclosure. Note that the following exemplary features [1] to [7] may be combined in any manner as long as they are not inconsistent.

[0011] [1] A generation step of dehydrating the solid-liquid mixture using a filter press device to generate a dehydrated cake; a collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the dehydrated cake produced in the producing step with the powder or granular material collected in the collecting step; A method for producing soil, comprising:

[0012] The manufacturing method [1] can produce soil by utilizing materials that are difficult to utilize effectively.

[0013] [2] A collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the powder and granular material collected in the collecting step with lime and gypsum; A method for producing soil, comprising:

[0014] The manufacturing method [2] can produce soil by utilizing materials that are difficult to utilize effectively.

[0015] [3] A production step of dehydrating the solid-liquid mixture using a filter press device to produce a dehydrated cake; a preparation step of preparing a mixture of at least one powder or granular material selected from the group consisting of crushed stone dust, lime dust, and fine aggregate, powder or granular material obtained by crushing rock, and powder or granular material containing granular sand; a mixing step of mixing the dehydrated cake produced in the producing step with the mixture prepared in the preparing step; A method for producing soil, comprising:

[0016] The soil manufacturing method [3] can produce soil by utilizing a solid-liquid mixture.

[0017] [4] In the mixing step, the dehydrated cake, the mixture prepared in the preparation step, lime, and gypsum are mixed. [3] A method for producing the soil described in [3].

[0018] The soil manufacturing method [4] can produce soil with a structure that is easier to solidify while making use of the solid-liquid mixture.

[0019] [5] A drying step of drying the dehydrated cake produced in the production step, In the mixing step, the dehydrated cake dried in the drying step is mixed with the mixture prepared in the preparation step. A method for producing the soil described in [3] or [4].

[0020] The soil manufacturing method [5] involves drying the dehydrated cake produced in the production process and mixing it with the above mixture, thereby making it possible to produce soil with a lower moisture content while preserving the solid-liquid mixture.

[0021] [6] In the drying step, the moisture content of the dehydrated cake is reduced to 30% or less. A method for producing the soil described in [5].

[0022] The soil manufacturing method of [6] can produce soil with an even lower moisture content while making use of the solid-liquid mixture.

[0023] [7] The filter press device has a plurality of filter plates for receiving the solid-liquid mixture, The filter plate includes a plate portion, a covering portion which is a drainage plate arranged to overlap the plate portion, and a waterproof material having any one of a waterproof plate material, a waterproof sheet material, and a waterproof layer, the covering portion has a water passage portion formed from one surface side to the other surface side of the covering portion, through which the liquid contained in the solid-liquid mixture passes; The waterproofing material has a surface made of a non-metallic material, The waterproofing material is sandwiched between the plate surface of the plate portion and the other surface of the covering portion, and the plate portion, the covering portion, and the waterproofing material overlap with each other. The waterproofing material receives the liquid that has passed from the one surface side to the other surface side of the covering portion on the surface of the non-metallic material, and allows the liquid to flow between the surface of the waterproofing material and the other surface. A method for producing soil according to any one of [3] to [6].

[0024] When producing dehydrated cake, which is used as soil material, a filter press device such as [7] is used instead of a general filter press device, which further increases the water permeability when squeezing the solid-liquid mixture, making it possible to produce dehydrated cake with a lower moisture content.

[0025] [8] The filter press device has a filter plate structure, The filter plate structure includes a filter plate portion having a plate-shaped base portion and a contact portion, and the filter plate portion and the contact portion approach and move away from each other, and when the contact portion is in a contact state in which the contact portion presses the filter plate portion, a filter chamber is formed by the filter plate portion and the contact portion, the substrate portion has an annular first pressing portion that presses the contact portion when in the contact state, the contact portion has a housing portion and a second pressing portion that is arranged to surround the housing portion and presses the first pressing portion when in the contact state, the first pressing portion includes a first sealing portion that is arranged to surround the filter chamber when in the tightly contacted state, the second pressing portion includes a second sealing portion that is disposed so as to surround the filter chamber when in the tightly contacted state, When the filter plate portion and the contact portion are close to each other, the first seal portion and the second seal portion press against each other to form a sealing portion, When the filter plate portion and the contact portion are separated from each other, the first seal portion and the second seal portion are separated from each other, When in the tightly contacted state, a convex portion of one of the first seal portion and the second seal portion enters into a concave portion of the other seal portion and presses against an inner surface of the concave portion. [7] A method for producing soil according to any one of [3] to [7].

[0026] When producing dehydrated cake, which is used as soil material, a filter press device such as [8] is used instead of a general filter press device. This makes it easier to increase the pressure inside the filter chamber when squeezing the solid-liquid mixture, which makes it easier to improve drainage, making it easier to produce dehydrated cake with a lower moisture content.

[0027] [9] A generation process in which a solid-liquid mixture generated at a construction site is dehydrated using a filter press device to generate a dehydrated cake; a preparation step of preparing a mixture of at least one powder or granular material selected from the group consisting of crushed stone dust, lime dust, and fine aggregate, powder or granular material obtained by crushing rock, and powder or granular material containing granular sand; a mixing step of mixing the dehydrated cake produced in the producing step with the mixture prepared in the preparing step to produce mixed soil; An arrangement process of arranging the mixed soil produced in the mixing process as soil at the construction site or in the vicinity of the construction site; Soil reuse methods, including:

[0028] First Embodiment 1-1. Overview of soil production methods The following description relates to a method for producing the soil. It should be noted that the drawings referred to in the following description are used to explain technical features, and unless otherwise specified, are not intended to be limiting and are merely illustrative examples.

[0029] The soil produced by the production method according to the first embodiment may be a soil solidification material, or may be soil other than a soil solidification material. When the produced soil is a soil solidification material, the soil solidification material may be a solidification material for improving and reusing sludge, soil, ponds, rivers, lakes, and dam sludge generated during construction and civil engineering work. Such soil solidification materials can be used, for example, for improving soft ground, improving road surfaces and roadbeds, building river embankments, and solidifying riverbed soil. When used as a soil solidification material, the soil to be solidified is not limited to these types, and various types of soil can be solidified.

[0030] In a manufacturing method according to a representative example of the first embodiment, soil (soil solidification material or soil other than soil solidification material) is manufactured as follows. In this manufacturing method, first, a generating step is performed in which a solid-liquid mixture is dehydrated using a filter press device 1 described below to produce a dehydrated cake. Then, a preparing step is performed in which at least one of powder and granular material, which is at least one of crushed stone dust, lime dust, and fine aggregate, or powder and granular material obtained by crushing rock, is prepared as a mixture. The preparing step may be performed before the generating step, after the generating step, or simultaneously with the generating step. Furthermore, a mixing step is performed in which the dehydrated cake produced in the generating step is mixed with the mixture prepared in the preparing step.

[0031] 1-2. Generation process (Outline of filter press equipment) The following description relates to an overview of the filter press apparatus 1. The filter press device 1 is a device that can dehydrate a solid-liquid mixture (for example, a slurry of sludge, excavated soil, cement, etc. mixed in water) and discharge a solidified material (cake) that remains after dehydrating the solid-liquid mixture.

[0032] As shown in Figures 2 and 3, the filter press device 1 has a filter plate group 5 including multiple filter plates 10 that move in a predetermined direction. In the following description, the direction in which the multiple filter plates 10 move (the predetermined direction) is the front-to-rear direction. In the example shown in Figure 3 and other figures, the thickness direction of each filter plate 10 when the multiple filter plates 10 are in close proximity (when adjacent filter plates are in contact with each other) is the front-to-rear direction. In the example shown in Figure 3 and other figures, the supply channel 62 side (the side into which the solid-liquid mixture is injected) is the front side, and the opposite side is the rear side. Furthermore, among the directions perpendicular to the front-to-rear direction, a predetermined first direction is the up-to-down direction. In the example shown in Figure 4 and other figures, the direction in which both sides of the rectangular filter plate 10 extend (the vertical direction) is the up-to-down direction. The up-to-down direction is preferably the vertical up-to-down direction, but may be slightly inclined relative to the vertical up-to-down direction. The direction perpendicular to the front-to-rear direction and the up-to-down direction is the left-to-right direction. In the example shown in FIG. 4 etc., the direction in which the upper and lower ends of the rectangular filter plate 10 extend is the left-right direction.

[0033] In the filter press device 1, a solid-liquid mixture is poured into the filter chamber 40 formed inside the filter plate group 5 when the filter plates 10 are in a close-contact state in which they are arranged close to each other and overlap in a predetermined direction (front-to-back direction) as shown in Figures 3 and 7. In the filter press device 1, the remaining solid-liquid mixture contained in the filter chamber 40 is discharged when the filter plates 10 are in a separated-away state in which they are separated from each other.

[0034] As shown in Figures 1 to 3, the filter press device 1 uses a filter plate structure 3, which is configured with filter plates 10 arranged in series. The filter plates 10 are plate-shaped parts that receive a solid-liquid mixture and discharge the liquid from the solid-liquid mixture. The filter plates 10 are configured by covering a plate-shaped base portion 11 with a through-hole 16 formed in the center with a filter cloth 18 stretched over it. The filter press device 1 has an approaching and separating device (detailed illustration is omitted in Figures 1 and 2) that can move the multiple filter plates 10 that make up the filter plate structure 3 toward and away from each other. When supplying a solid-liquid mixture to the filter press device 1, adjacent filter plates 10 are stacked together in close contact (see Figures 1, 2, 7, etc.), and the solid-liquid mixture (e.g., a slurry such as muddy water) is pressurized and forced into the through-holes 16 of each filter plate 10 using a pump. The solid-liquid mixture is forced into the filter chamber 40 shown in Figures 2, 7, etc. under high internal pressure, and the water is discharged through minute gaps in the filter cloth 18. A solid (dehydrated cake) is formed between adjacent filter plates 10 (specifically, between the filter cloths 18 of adjacent filter plates 10) as a solidified residue from which a large amount of water has been removed from the solid-liquid mixture supplied by the pump. Water that flows into the filter plate 10 through the holes in the filter cloth 18 is discharged to the outside (bottom) of the filter plate 10 through the drainage channel 28 within the filter plate 10. This point will be described in detail later.

[0035] (Details of filter plate structure) The following description relates to the details of the filter plate structure 3. As shown in Figure 7, the filter plate structure 3 is a structure composed of multiple filter plates 10. Each filter plate 10 has a central recess 12 and a peripheral protrusion 14 formed on one side and the other side in the plate thickness direction, respectively. In this example, any one of the filter plates 10 corresponds to an example of a filter plate portion, and the adjacent filter plate 10 configured to be able to adhere to and separate from that filter plate 10 corresponds to an example of an adhering portion.

[0036] The center recess 12 is a portion recessed in the plate thickness direction around the through hole 16. In Figure 7 and other figures, of the two center recesses 12 formed on each filter plate 10, the recess on one side (the side on which the annular protrusion 24 is formed) is referred to as one center recess 12A (or simply as center recess 12A), and the recess on the other side (the side on which the annular recess 34 is formed) is referred to as the other center recess 12B (or simply as center recess 12B). As shown in Figures 8 and 9, one center recess 12A has a rectangular outer diameter when viewed from the front side. As shown in Figures 11 and 12, the other center recess 12B has a rectangular outer diameter when viewed from the back side.

[0037] The peripheral side protrusion 14 is a portion that is formed in a frame shape surrounding the central side recess 12, has a shape that is convex in the plate thickness direction, and is at least partially arranged in a ring shape around the central side recess 12. As shown in Figures 8 and 9, the peripheral side protrusion 14A on one side (the side on which the annular protrusion 24 is formed) is a rectangular frame portion when viewed from the front side, and is arranged in a quadrangular shape (specifically, a square shape) so as to fit along the peripheral edge of the filter plate 10. As shown in Figures 11 and 12, the peripheral side protrusion 14B on the other side (the side on which the annular recess 34 is formed) is a rectangular frame portion when viewed from the front, and is arranged in a quadrangular shape (specifically, a square shape) so as to fit along the peripheral edge of the filter plate 10.

[0038] As shown in Figures 8 and 9, the peripheral side convex portion 14A on one side (the side on which the annular convex portion 24 is formed) is formed with a first pressing surface 22 arranged in a ring shape (specifically, in a rectangular frame shape) around the central side recess 12A, and an annular convex portion 24 arranged in a ring shape (specifically, in a rectangular frame shape) around the central side recess 12A and protruding from the first pressing surface 22.

[0039] In the examples of Figures 6 and 7, the filter plate 10 on the left side of the drawing can function as a filter plate portion having a plate-shaped base portion, and the filter plate 10 on the right side of the drawing can function as a contact portion. When the filter plate portion and the contact portion approach and separate from each other and are in a contact state in which the contact portion presses the filter plate portion, a filter chamber is formed with the filter plate portion and the contact portion. In this case, the peripheral side protrusion 14A of the filter plate 10 on the left side of the drawing corresponds to an example of an annular first pressing portion, which functions to press the contact portion in the contact state, and the annular side protrusion 24 on the left side of the drawing corresponds to an example of a first sealing portion, which is arranged to surround the filter chamber in the contact state. Also, in this case, the center side recess 12B of the filter plate 10 on the right side of the drawing corresponds to an example of a storage portion. And in this case, the peripheral side protrusion 14B of the filter plate 10 on the right side of the drawing corresponds to an example of an annular second pressing portion, which is arranged to surround the storage portion and functions to press the first pressing portion in the contact state. In this case, the annular recess 34 corresponds to an example of a second seal portion and is arranged to surround the filter chamber when in a tightly contacted state. In this example, when the filter plate portion and the tightly contacted portion are close to each other, the first seal portion (annular protrusion 24) and the second seal portion (annular recess 34) press against each other to form a sealing portion, and when the filter plate portion and the tightly contacted portion are separated from each other, the first seal portion and the second seal portion separate. When in the tightly contacted state, the protrusion of one of the first and second seal portions (annular protrusion 24 in the example of FIG. 7) enters the recess of the other seal portion (annular recess 34 in the example of FIG. 7) and presses against the inner surface of the recess.

[0040] The annular protrusion 24 is made of an elastic material such as rubber or a non-rubber elastomer, and is fixed to the peripheral protrusion 14A by fitting into a groove (a groove formed to surround the central recess 12A) formed on the first pressing surface 22 of the peripheral protrusion 14A. As shown in FIG. 7, the annular protrusion 24 has a curved shape such that the outer shape of a cross section cut in a plane direction perpendicular to the extension direction of the annular protrusion 24 is convex outward. The annular protrusion 24 is hollow, with a void 24A formed therein. The void 24A is formed outside the position of the first pressing surface 22 in the thickness direction of the filter plate 10 (farther from the center in the thickness direction), extends along the extension direction of the annular protrusion 24, and is arranged in a ring shape around the central recess 12.

[0041] As shown in Figures 11 and 12, the peripheral side convex portion 14B on the other side (the side on which the annular recess 34 is formed) is formed with a second pressing surface 32 arranged in a ring shape (specifically, in a rectangular frame shape) around the central side recess 12B, and an annular recess 34 arranged in a ring shape (specifically, in a rectangular frame shape) around the central side recess 12B and recessed from the second pressing surface 32.

[0042] 7 to 13, in each filter plate 10, a through-hole 16 is formed so as to penetrate in the plate thickness direction between a central recess 12A on one side (the side on which the annular protrusion 24 is formed) and a central recess 12B on the other side (the side on which the annular recess 34 is formed). The through-hole 16 functions as a flow path that allows the solid-liquid mixture to flow in the thickness direction of the filter plate 10 so as to pass through the inside of the filter plate 10.

[0043] As shown in Figures 7 and 8, filter cloth 18 is arranged on one surface side in the plate thickness direction so as to cover the area outside through hole 16, and as shown in Figures 7 and 11, filter cloth 18 is arranged on the other surface side in the plate thickness direction so as to cover the area outside through hole 16. Note that in Figure 7, two filter cloths 18 interposed between first pressing surface 22 and second pressing surface 32 and between annular convex portion 24 and annular recessed portion 34 are omitted from the illustration. In Figures 7, 8, and 11, the filter cloth 18 covering one surface side (the surface side on which annular convex portion 24 is formed) is referred to as filter cloth 18A, and the filter cloth 18 on the other surface side (the surface side on which annular recessed portion 34 is formed) is referred to as filter cloth 18B.

[0044] As shown in FIGS. 7 and 8, the filter cloth 18A on one side (the side on which the annular convex portion 24 is formed) is fixed to the annular plate portion 15A (described later) and is disposed entirely around the outer region of the annular plate portion 15A, extending to the peripheral edge of the base portion 11. As shown in FIGS. 7 and 11, the filter cloth 18B on the other side (the side on which the annular concave portion 34 is formed) is fixed to the annular plate portion 15B (described later) and is disposed entirely around the outer region of the annular plate portion 15B, extending to the peripheral edge of the base portion 11. In FIG. 7, the filter cloth 18 is conceptually shown by a two-dot chain line, and in FIGS. 8 and 11, the filter cloth 18 is conceptually shown as a patterned region. In the example of FIG. 7, the filter cloths 18A and 18B are also present in the portion sandwiched between the peripheral convex portions 14A and 14B, but the illustration of the filter cloths 18A and 18B in this portion (illustration by the two-dot chain line) is omitted. 7 and the like, the peripheral edge of filter cloth 18A and the peripheral edge of filter cloth 18B are connected to each other in each filter plate 10, but the peripheral edges do not have to be connected to each other. Filter cloth 18A only needs to be arranged so as to cover the inner surface of center recess 12A at least in the area outside through-hole 16, and the covered area of ​​filter cloth 18A is not limited to the configurations shown in FIGS. 7, 8, 11, and the like.

[0045] The filter press device 1 can switch the filter plate structure 3 shown in Figures 2, 3, 7, etc. between a state in which adjacent filter plates 10 are in close contact with each other as shown in Figures 5(A) and 7, and a state in which adjacent filter plates 10 are spaced apart as shown in Figure 5(B). Figure 5 is a simplified diagram showing the configuration of a portion of the filter plate structure 3 viewed from above. Figure 5(A) is a diagram showing a state in which adjacent filter plates 10 are in contact with each other. Figures 5(A) and 7 show the state when a solid-liquid mixture is being poured into the filter plate group 5. Figure 5(B) shows the state when residual material (dehydrated cake) is being discharged from the filter plate group 5.

[0046] 1, 2, and 3, the thickness direction of the multiple filter plates 10 is aligned (i.e., the thickness direction of each filter plate 10 is aligned in the same direction), and the position of the outer periphery of each filter plate 10 (the position of the outer periphery in a plane direction perpendicular to the thickness direction) is aligned, and when each filter plate 10 moves along the rail in this aligned state, adjacent filter plates 10 among the multiple filter plates 10 can move toward and away from each other. During the movement of the multiple filter plates 10, the movement of each filter plate 10 in the left-right direction is restricted, and the movement of each filter plate 10 in the up-down direction is also restricted, so that each filter plate 10 can move while maintaining an attitude in which the thickness direction is, for example, the front-to-back direction.

[0047] When multiple filter plates 10 are stacked so that one filter plate 10 is in close contact with another filter plate 10, as shown in Figures 5(A) and 7, the annular protrusion 24 of one filter plate 10 enters the annular recess 34 of the other filter plate 10 and presses against the inner surface of the annular recess 34, as shown in Figure 7, and the first pressing surface 22 of one filter plate 10 and the second pressing surface 32 of the other filter plate 10 press against each other. In the example of Figure 7, two filter cloths 18A, 18B covering the two filter plates 10, respectively, are interposed between the first pressing surface 22 of one filter plate 10 and the second pressing surface 32 of the other filter plate 10, and in this state, the first pressing surface 22 of one filter plate 10 and the second pressing surface 32 of the other filter plate 10 press against each other. That is, the first pressing surface 22 of one filter plate 10 and the second pressing surface 32 of the other filter plate 10 press against each other via the filter cloth 18A of the first filter plate 10 and the filter cloth 18B of the other filter plate 10. Two filter cloths 18A, 18B covering the two filter plates 10 are also interposed between the annular protrusion 24 and the annular recess 34, and in this state (i.e., a state in which the filter cloths 18A, 18B are interposed between the outer surface of the annular protrusion 24 and the inner surface of the annular recess 34), the annular protrusion 24 and the annular recess 34 press against each other. That is, the annular protrusion 24 of the first filter plate 10 presses against the inner surface of the annular recess 34 via the filter cloth 18A of the first filter plate 10 and the filter cloth 18B of the other filter plate 10.

[0048] As shown in Figures 2, 3, and 7, when a solid-liquid mixture is introduced, each filter plate 10 of the filter plate group 5 is stacked in close contact with its neighboring filter plate 10, and the solid-liquid mixture is poured into the filter plate group 5 through the through-holes 16 by a first injection device 60 (e.g., a slurry supply device including a pump) shown in Figure 2. The solid-liquid mixture injected into the filter plate group 5 through the through-holes 16 accumulates in the filter chambers 40 shown in Figure 7 and other figures under high internal pressure, and moisture is discharged through minute gaps in the filter cloth 18 to the substrate portion 11 side (i.e., the back side of the filter cloth 18). A dehydrated cake is formed as a residue between adjacent filter plates 10 (specifically, between the filter cloths of adjacent filter plates 10). The dehydrated cake is a substance obtained by removing a certain amount of moisture from the solid-liquid mixture 7 injected into the filter chambers 40.

[0049] As shown in FIG. 7, each filter plate 10 is provided with a base plate 11. The base plate 11 is configured in a plate shape. The base plate 11 includes a plate-like body 11A and peripheral side protrusions 14A and 14B. The base plate 11 has one of the two center side recesses 12, a center side recess 12A, and one of the two peripheral side protrusions 14, a peripheral side protrusion 14A, formed on one plate surface side (the one surface side mentioned above). Furthermore, the base plate 11 has the other of the two center side recesses 12, a center side recess 12B, and the other of the two peripheral side protrusions 14, a peripheral side protrusion 14B, formed on the other plate surface side (the other surface side mentioned above). The filter plate 10 is provided with a filter cloth 18A covering the inner wall portion of one center side recess 12A, and a filter cloth 18B covering the inner wall portion of the other center side recess 12B. In one center recess 12A and the other center recess 12B, drainage channels 28 (one drainage channel 28A and the other drainage channel 28B) leading to the outside of the filter plate 10 are provided on the back side of the filter cloth 18. The drainage channels 28 are flow paths that communicate with the inter-component space between the drainage plate 13 (covering portion) and the waterproof material 100 and the external space of the filter plate 10, and are flow paths that allow liquid to flow from the inter-component space to the external space. The inter-component space is the gap space between the drainage plate 13 (covering portion) and the waterproof material 100, and liquid flows from this gap space into the space within the drainage channels 28.

[0050] In each of the central recesses 12A and 12B of the filter plate 10, a drainage plate 13 (one drainage plate 13A and the other drainage plate 13B) having a water passage portion that allows liquid to pass through in the thickness direction of the plate is provided on the inner wall portion (inner surface portion) at the deepest side in the depth direction. The drainage plate 13 corresponds to an example of a covering portion and is arranged overlapping the plate body 11A (plate portion) so as to cover the plate body 11A. The water passage portions of both drainage plates 13A and 13B may be composed of multiple holes, grooves, or notches. The drainage plates 13A and 13B may be configured so that water can pass from the front side to the back side while supporting the filter cloth 18 on the front side. They may be configured so that multiple through holes are formed in the plate body, or may have a mesh-like configuration.

[0051] In the base plate portion 11, plate-like bodies 11A are provided on the inner side of the drainage plates 13 in the thickness direction (the thickness direction of the filter plate 10), and both sides in the thickness direction are covered by the drainage plates 13. The plate-like bodies 11A correspond to an example of a plate portion. The plate-like bodies 11A are made of, for example, a metal material or are mainly made of a metal material, for example, a metal plate. As shown in FIG. 7, one peripheral side protrusion 14A is a rectangular frame body fixed along the peripheral portion of the plate-like body 11A on one side of the plate-like body 11A. One peripheral side protrusion 14A corresponds to an example of a frame portion, is formed in an annular shape, and is overlapped on and fixed to the plate-like body 11A (plate portion). The other peripheral side protrusion 14B is a rectangular frame body fixed along the peripheral portion of the plate-like body 11A on the other side of the plate-like body 11A. One drainage plate 13A is fixed with its peripheral edge sandwiched between plate-like body 11A and the inner edge of the frame that forms peripheral convex portion 14A. The other drainage plate 13B is fixed with its peripheral edge sandwiched between plate-like body 11A and the inner edge of the frame that forms peripheral convex portion 14B.

[0052] In the plate-like body 11A, drainage channels 28A and 28B are respectively formed at predetermined positions on the back side of each drainage plate 13 (one drainage plate 13A and the other drainage plate 13B), leading to the outside of the filter plate 10. Both drainage channels 28A and 28B are formed as water passages that allow water to pass through.

[0053] The drainage channels 28A formed on the back side of the filter cloth 18A in one of the central recesses 12A are, for example, as shown in Figures 7 to 10. In the example of Figures 7 to 9, multiple drainage channels 28A are formed in a groove-like shape at the lower end side (vertical lower end side when installed) of one surface of the base portion 11, and water can flow through each of the drainage channels 28A. One end (upper end) of each of the multiple drainage channels 28A is located on the back side of the drainage plate 13A, and a portion of the back surface of the drainage plate 13A faces the internal space of each of the drainage channels 28A. Gaps in the drainage plate 13A that communicate with the internal space of the drainage channels 28A are configured so that water passing through the gaps flows into the drainage channels 28A. The other end (lower end) of each of the drainage channels 28A reaches the lower end of the filter plate 10, and the internal space of each of the drainage channels 28A communicates with the space outside the filter plate 10. Furthermore, it is desirable that there is a space between the back surface of the drainage plate 13A and the surface of the plate-shaped body 11A, and that this space is connected to each drainage channel 28A.If configured in this manner, moisture that flows into the back surface of the drainage plate 13A will easily flow to the outside of the filter plate 10 through each drainage channel 28A.

[0054] The drainage channels 28B formed on the back side of the filter cloth 18B in one of the central recesses 12B are, for example, as shown in Figures 7 and 11 to 13. In the examples shown in Figures 7 and 11 to 13, multiple drainage channels 28B are formed in a groove-like shape at the lower end (vertical lower end when installed) of one surface of the base portion 11, and water can flow through each of the drainage channels 28B. One end (upper end) of each of the multiple drainage channels 28B is located on the back side of the drainage plate 13B, and a portion of the back surface of the drainage plate 13B faces the internal space of each of the drainage channels 28B. The gaps in the drainage plate 13B that communicate with the internal space of the drainage channels 28B are configured so that water passing through the gaps flows into the drainage channels 28B. The other end (lower end) of each of the drainage channels 28B reaches the lower end of the filter plate 10, and the internal space of each of the drainage channels 28B communicates with the space outside the filter plate 10. Furthermore, it is desirable that there is a space between the back surface of the drainage plate 13B and the surface of the plate-shaped body 11A, and that this space be connected to each drainage channel 28B.If configured in this manner, moisture that flows into the back surface of the drainage plate 13B will easily flow to the outside of the filter plate 10 through each drainage channel 28B.

[0055] In the examples of Figures 6 to 14, a configuration is shown in which multiple drainage channels 28 are provided on the lower end side of the filter plate 10, but any flow path can be used as long as it can discharge water that has flowed through the filter cloth 18 into the drainage plate 13 side to the outside of the filter plate 10.

[0056] As shown in Figures 7, 10, 13, and 14, the waterproof material 100 is made of a waterproof plate material or a waterproof sheet material. The waterproof material 100 is configured to be thinner than the plate-shaped body 11A (plate portion). The waterproof material 100 may be a plate material mainly made of a non-metallic material, or may be a sheet material mainly made of a non-metallic material. Examples of non-metallic materials include polymeric materials such as resin materials and ceramic materials. In a typical example, the waterproof material 100 is made of a resin plate or resin sheet.

[0057] The waterproof material 100 is sandwiched between the plate surface of the plate-shaped body 11A (plate portion) and the other side (the surface facing the plate-shaped body 11A) of the drainage plate 13 (covering portion). One waterproof material 100A is sandwiched between one drainage plate 13A and the plate-shaped body 11A. The other waterproof material 100B is sandwiched between the other drainage plate 13B and the plate-shaped body 11A. The filter plate 10 configured in this manner is designed so that liquid flows between the surface of the waterproof material 100 and the other side (the surface of the drainage plate 13 facing the plate-shaped body 11A). In the filter plate 10, the other side of the drainage plate 13 (the surface of the drainage plate 13 facing the plate-shaped body 11A) is an uneven surface having a convex surface that is convex toward the waterproof material 100 and a concave surface that is concave toward the opposite side of the waterproof material 100. The drainage plate 13 is a plate-shaped drainage plate having holes formed therethrough in the thickness direction of the plate, but grooves, recesses, etc. may be formed on the other surface of the drainage plate 13.

[0058] As shown in Figures 6 to 13, the filter plate 10 has a pair of annular plate portions 15A and 15B fixed respectively within one center recess 12A and the other center recess 12B of the base plate portion 11. The annular plate portions 15A and 15B are formed with through-hole-side protrusions 17A and 17B that protrude in the thickness direction of the filter plate 10. A plurality of through-hole-side protrusions 17A protrude from the annular plate portion 15A on one side, and the plurality of through-hole-side protrusions 17A are arranged around the periphery of the through-hole 16 to surround the through-hole 16, as shown in Figures 8 and 9. Similarly, a plurality of through-hole-side protrusions 17B protrude from the annular plate portion 15B on the other side, and the plurality of through-hole-side protrusions 17B are arranged around the periphery of the through-hole 16 to surround the through-hole 16, as shown in Figures 11 and 12. The through hole 16 is formed in a configuration that communicates from one annular plate portion 15A of the pair of annular plate portions 15A, 15B to the other annular plate portion 15B, and specifically, the inside of the cylindrical portion that connects the pair of annular plate portions 15A, 15B is the through hole 16. In this configuration, as shown in Figure 7, when one side of one filter plate 10 and the other side of the other filter plate 10 are overlapped so as to press against each other, the through hole side protrusion 17A on one side of the one filter plate 10 and the through hole side protrusion 17B on the other side of the other filter plate 10 are configured to face each other. 2, when the through-hole-side protrusions 17A on one side of one filter plate 10 and the through-hole-side protrusions 17B on the other side of the other filter plate 10 face each other, the distance (distance between the tips) between these through-hole-side protrusions 17A, 17B is smaller than the distance between the plate surfaces of the annular plate portions 15A, 15B, and may be zero (i.e., the opposing through-hole-side protrusions 17A, 17B may be in contact). Note that in the example of FIG. 2, etc., no filter cloth 18 is interposed between the opposing through-hole-side protrusions 17A, 17B.

[0059] Within one central recess 12A and the other central recess 12B, a drain plate-side protrusion 19 (one drain plate-side protrusion 19A and the other drain plate-side protrusion 19B) is formed, protruding in the thickness direction beyond each drain plate 13. One drain plate-side protrusion 19A is fixed to at least either the drain plate 13A or the plate-like body 11A, and is configured to protrude beyond the surface of the drain plate 13A in the thickness direction (thickness direction of the filter plate 10). The drain plate-side protrusion 19A has a tapered shape that becomes thinner as it approaches the tip end in the protruding direction. In the example of Figures 8 and 9, multiple drain plate-side protrusions 19A configured in this way are arranged to surround the through hole 16. The other drainage plate-side protrusion 19B is fixed to at least one of the drainage plate 13B or the plate-like body 11A and is configured to protrude in the plate thickness direction (the plate thickness direction of the filter plate 10) beyond the surface of the drainage plate 13B. The drainage plate-side protrusion 19B has a tapered shape that becomes thinner as it approaches the tip end in its protruding direction. In the example of Figures 11 and 12, multiple drainage plate-side protrusions 19B configured in this manner are arranged to surround the through hole 16. When one side of one filter plate 10 and the other side of another filter plate 10 are stacked and pressed against each other as shown in Figure 7, each drainage plate-side protrusion 19A on one side of the first filter plate 10 and each drainage plate-side protrusion 19B on the other side of the other filter plate 10 are configured to face each other. As shown in Figure 7, when the drainage plate-side protrusion 19A on one side of one filter plate 10 and the drainage plate-side protrusion 19B on the other side of the other filter plate 10 face each other, the distance (distance between the tips) between these drainage plate-side protrusions 19A, 19B is smaller than the distance between the opposing drainage plates 13A, 13B. In the example of Figure 7, etc., filter cloths 18A, 18B are interposed between the opposing drainage plate-side protrusions 19A, 19B, and the filter cloths 18A, 18B are sandwiched between the opposing drainage plate-side protrusions 19A, 19B.

[0060] (Configuration of holding device, etc.) The filter press device 1 shown in Figures 1 to 3 has such a filter plate structure 3. As shown in Figures 2 and 3, the filter press device 1 is configured so that the multiple filter plates 10 constituting the filter plate structure 3 can be moved back and forth along guide rails 90 (guide rails 90A, 90B) while the multiple filter plates 10 are aligned in a predetermined position (i.e., the thickness direction of each filter plate 10 is the same and the positions of the outer peripheries of each filter plate 10 are aligned), and this movement allows adjacent filter plates among the multiple filter plates 10 to move closer to and away from each other.

[0061] Although not shown in Figures 8 to 13, as shown in Figures 2 to 4, each filter plate 10 has a pair of protrusions 41, 42 that protrude laterally from both the left and right sides of the base portion 11 of each filter plate 10. These pair of protrusions 41, 42 function as a pair of supported portions. The pair of protrusions 41, 42 are supported while being placed on guide rails 90A, 90B, respectively. In multiple filter plates 10, the pair of protrusions 41, 42 move while being placed on the guide rails 90A, 90B. The pair of guide rails 90A, 90B correspond to an example of a support member and function to support the protrusions 41, 42. During this movement, each filter plate 10 moves in the front-to-rear direction (the thickness direction of each filter plate 10) while maintaining a predetermined posture as shown in Figures 3, 4, etc. Note that the filter press device 1 may be provided with an additional mechanism for maintaining the posture of the filter plate 10 in addition to the configuration shown in Figures 3 and 4.

[0062] As shown in Figures 2 and 3, the filter press apparatus 1 includes, in addition to the filter plate structure 3 described above, a holding device 50, a first injection device 60, a second injection device 70, a supply path 62, a supply path 72, a first switching unit 81, and a second switching unit 82. In Figure 2 and other figures, the first injection device 60 is also referred to as a slurry supply device, and the second injection device 70 is also referred to as an air supply device. The supply path 62 is a path for supplying a solid-liquid mixture 7 from the first injection device 60 to the filter plate group 5, and the supply path 72 is a path for supplying air from the second injection device 70 to the filter plate group 5. The first switching unit 81 is a device for switching the supply path 62 between a state in which the solid-liquid mixture can be supplied from the first injection device 60 to the filter plate group 5 (open state) and a state in which the solid-liquid mixture cannot be supplied (closed state). The second switching unit 82 is a device that switches the supply path 72 between a state (open state) in which air can be supplied from the second injection device 70 to the filter plate group 5, and a state (blocked state) in which air cannot be supplied. Although not shown in Figures 2 and 3, the filter press apparatus 1 also includes a control device (for example, an information processing device such as a computer) that controls the operations (operation timing, control amount, etc.) of the holding device 50, the first injection device 60, the second injection device 70, the first switching unit 81, and the second switching unit 82.

[0063] The holding device 50 comprises a pair of guide rails 90 (guide rails 90A, 90B), a drive unit 54, and fixed walls 51, 52, which are assembled together. The drive unit 54 comprises an operating portion 54C that acts on the filter plates 10 at the end (the end on the fixed wall 52 side) of the filter plate group 5, a drive shaft 54B connected to the operating portion 54C, and a drive unit 54A that moves the drive shaft 54B in a predetermined direction (the plate thickness direction of each filter plate 10 in the filter plate group 5). When the drive unit 54A moves the operating portion 54C toward the fixed wall 51 via the drive shaft 54B, the multiple filter plates 10 are pressed toward the fixed wall 51 while maintaining a predetermined posture, and adjacent filter plates in the filter plate group 5 come into contact with each other, as shown in Figures 2 and 3. Meanwhile, when the drive unit 54A moves the operating unit 54C toward the fixed wall 52 via the drive shaft 54B, adjacent filter plates in the filter plate group 5 are spaced apart. For example, if a spacing restricting unit (not shown) is provided to restrict the maximum spacing between adjacent filter plates 10 to a predetermined spacing, when the operating unit 54C engages or holds a filter plate 10 at an end (the end on the fixed wall 52 side) of the filter plate group 5 and operates to move the filter plate 10 toward the fixed wall 52, the filter plates will move so that adjacent filter plates are spaced apart. Note that the example described here is merely one example, and the holding device may have other configurations as long as it is capable of moving the filter plates 10 closer to and farther from each other while aligning them in a predetermined position (i.e., a position in which the thickness directions of the filter plates 10 are the same and the outer peripheral edges of the filter plates 10 are aligned).

[0064] In this way, by moving the acting portion 54C toward the fixed wall 51, the holding device 50 can arrange multiple filter plates 10 in a stacked state as shown in Figures 2 and 3, and hold them in a holding state (first holding state) in which the annular convex portion 24 of one filter plate 10 enters into the annular recess 34 of the other filter plate 10 between adjacent filter plates and presses against the inside of the annular recess 34, and the first pressing surface 22 of one filter plate 10 and the second pressing surface 32 of the other filter plate 10 press against each other.

[0065] The first injection device 60 is a transfer device that transfers a solid-liquid mixture from a solid-liquid mixture storage unit (not shown, e.g., a slurry storage tank) to the filter plate group 5. When the first switching unit 81 is in an open state and the supply line 62 is connected to the through-holes 16 at the end of the filter plate group 5, the first injection device 60 can inject the solid-liquid mixture 7 into the filter plate group 5 through the through-holes 16 of the filter plates 10 at one end of the filter plate group 5 when the holding device 50 holds the filter plate group 5 in the first holding state as shown in Figures 2 and 3. The first switching unit 81 is a device that switches between a first stop state, which stops the inflow and outflow of fluid at the one end of the filter plate group 5, and a first release state, which releases the first stop state. The first switching unit 81 is configured with a known solenoid valve that switches the supply line 62 (pipe) between an open state and a shut-off state. The opening and closing operations of the first switching unit 81 are controlled by, for example, a control device (not shown).

[0066] The second injection device 70 is configured as a known air supply device capable of pressurizing and feeding air. When the second switching unit 82 is in an open state and the supply path 72 is connected to the through-hole 16 at the end of the filter plate group 5, the second injection device 70 injects air into the filter plate group 5 through the supply path 72. When the holding device 50 holds the filter plate group 5 in the first holding state as shown in Figures 2 and 3, the second injection device 70 injects air into the filter plates 10 through the through-hole 16 at the other end of the filter plate group 5 opposite the one end. The second switching unit 82 is a device that switches between a second stop state, which stops the flow of fluid into and out of the other end of the filter plate group 5, and a second release state, which releases the second stop state. The second switching unit 82 is configured as a known solenoid valve that switches the supply path 72 (pipe) between an open state and a closed state. The opening and closing operations of the second switching unit 82 are controlled, for example, by a control device (not shown).

[0067] (Injection and discharge operations) In the filter press apparatus 1, before injecting the solid-liquid mixture 7, the holding device 50 operates the filter plate group 5 to hold the filter plate group 5 in the first holding state described above. In the first holding state, as shown in FIGS. 2, 3, and 7, each of the filter plates 10 is in close contact with its adjacent filter plate 10. In the filter press apparatus 1, when the holding device 50 holds the filter plate group 5 in the first holding state as shown in FIGS. 3 and 7, the second switching unit 82 is set to the second stop state (a state in which the supply path 72 is blocked) and the first switching unit 81 is set to the first release state (a state in which the supply path 62 is opened). In this state, the first injecting device 60 performs a solid-liquid mixture injecting operation to inject the solid-liquid mixture 7 into the filter plate group 5. This solid-liquid mixture injecting operation fills each filter chamber 40 formed in the filter plate group 5 with the solid-liquid mixture 7, and some of the water contained in the solid-liquid mixture 7 is discharged through the drainage channel 28. The operation timing and operation time of each device are controlled by a control device (not shown).

[0068] In the filter press apparatus 1, after the first injection device 60 injects the solid-liquid mixture 7 into the filter plate group 5, the holding device 50 maintains the first holding state as shown in Figures 2, 3, and 7, while the first switching unit 81 is switched to the first stopped state (a state in which the supply path 62 is blocked) and the second switching unit 82 is switched to the second open state (a state in which the supply path 72 is open). In this state, the second injection device 70 performs an air injection operation to inject air into the filter plate group 5. This air injection operation supplies air into each filter chamber 40 formed in the filter plate group 5, and the pressure of the air promotes the discharge of water from the solid-liquid mixture 7 remaining in the filter chamber 40. Specifically, during the air injection operation, air flows from the through-hole 16 at the other end of the filter plate group 5 to the drainage channel 28 of each filter plate 10, and the liquid (moisture) of the solid-liquid mixture 7 present inside the filter plate group 5 is discharged together with the air to the outside of the filter plate group 5 through the drainage channel 28. The operation timing and operation time of each device are controlled by a control device (not shown).

[0069] After the solid-liquid mixture injection operation (specifically, after the air injection operation), the filter press apparatus 1 performs a discharge operation to discharge the residue (dehydrated cake) remaining in the filter chamber 40. In the filter press apparatus 1, after the air injection operation, the drive unit 54A of the holding device 50 moves the action unit 54C to the other side in the front-to-rear direction (toward the fixed wall 52) via the drive shaft 54B, thereby separating adjacent filter plates in the filter plate group 5. Specifically, during the discharge operation, the holding device 50 moves each filter plate 10 in turn, starting from the filter plate 10 at the end of the filter plate group 5, to the other side in the front-to-rear direction (toward the drive unit 54A). During this discharge operation, as the holding device 50 moves each filter plate 10 in turn to the other side in the forward / backward direction, the state changes from Fig. 5(A) to Fig. 5(B) near each filter plate 10, and residue (dehydrated cake 7A) is discharged downward between the filter plate 10 that most recently started moving to the other side in the forward / backward direction and the filter plate 10 adjacent to that filter plate 10 on one side in the forward / backward direction (the filter plate 10 that is scheduled to move to the other side next in the forward / backward direction). In other words, when the filter plate 10 that most recently started moving moves away from the next filter plate 10 that is kept stationary, the residue (dehydrated cake 7A) held between the two filter plates 10 falls downward. During the discharge operation, when the distance between the filter plate 10 that most recently started to move in the other direction in the forward / backward direction and the next filter plate 10 (the filter plate 10 adjacent to one side in the forward / backward direction of the filter plate 10 that most recently started to move in the other direction in the forward / backward direction) reaches its maximum distance, the holding device 50 moves each filter plate 10 in turn in the other direction in the forward / backward direction so that a distance control member attached to the multiple filter plates 10 moves the next filter plate 10 in the other direction in the forward / backward direction.

[0070] This discharge operation allows the distance between adjacent filter plates to be increased, as shown in FIG. 5(B), so that the remaining material (dehydrated cake 7A) falls downward. As shown in FIGS. 5(A) and 5(B), when two adjacent filter plates 10, 10 change from a close state to a far state, the left-right movement of each filter plate 10 is restricted, and the up-down movement of each filter plate 10 is also restricted. Each filter plate 10 can move while maintaining an orientation in which, for example, the plate thickness direction is the front-to-rear direction and the direction in which both side portions 10A extend is the up-to-down direction, as shown in FIG. 4. Note that slight changes in the orientation of each filter plate 10 may be permitted during the movement of each filter plate 10. The side portions 10A of each filter plate 10 form the side portion 5A of the filter plate group 5. Specifically, the side portions 10A on one side of the multiple filter plates 10 are arranged in a front-to-back arrangement to form the side portion 5A of the filter plate group 5. Similarly, the other side portions 10A of the plurality of filter plates 10 are arranged in a row in the front-rear direction to form the other side portion 5A of the filter plate group 5.

[0071] (Details of the covering and waterproofing material) The following describes in detail the configuration of one waterproofing material 100 (specifically, waterproofing material 100B) and one drainage plate 13 (specifically, drainage plate 13B). The configurations described below also apply to the waterproofing material 100A and the drainage plate 13A.

[0072] As shown in Figures 14, 16, and 17, the waterproofing material 100 is made of a plate material made of a resin material or a sheet material made of a resin material, and is configured to be thinner than the plate-shaped body 11A (plate portion). In the example of Figure 14, the waterproofing material 100 is made of a resin sheet, but it may also be a plate material. In the example of Figure 14, the plate-shaped body 11A (plate portion) is made of a metal material, and specifically is configured as a metal plate material. The waterproofing material 100 is thinner than the thickest part of the plate-shaped body 11A (plate portion). The waterproofing material 100 is configured to block the passage of liquid from one side of the waterproofing material 100 to the other side.

[0073] As shown in FIG. 17, the thickness of the waterproof material 100 is smaller than the thickness of the drainage plate 13 (covering portion). Specifically, the waterproof material 100 is thinner than the thickest part of the drainage plate 13 (covering portion). The surface roughness of the surface 100Z of the waterproof material 100 on the drainage plate 13 side (covering portion side) is smaller than the surface roughness of the plate surface of the plate-shaped body 11A (plate portion) on the drainage plate 13 side. The waterproof material 100 is detachable from the plate-shaped body 11A (plate portion). The waterproof material 100 may be detachably fixed to the plate-shaped body 11A with fastening members such as screws or bolts, or may be detachably attached to the plate-shaped body 11A with an adhesive medium such as an adhesive or an adhesive sheet.

[0074] As shown in Figures 15, 16(B), and 17, the drainage plate 13 is formed with a water passage portion 138 that allows liquid to pass from one side of the drainage plate 13 to the other side. The drainage plate 13 is configured in a plate-like, mesh-like shape. The water passage portion 138 is a hole portion that penetrates the drainage plate 13 in the thickness direction. The drainage plate 13 is made of a non-metallic material such as a resin material.

[0075] As shown in FIG. 15(A), on one surface 13X of the drainage plate 13 (specifically, the surface that comes into contact with the filter cloth 18), rib-like protrusions 132 extending in a first direction (specifically, the horizontal direction, i.e., the left-right direction) are formed so as to protrude toward one side (the filter cloth 18 side). The multiple protrusions 132 extend parallel to one another. A recess is formed between two adjacent protrusions 132 among the multiple protrusions 132. The water passage portions 138 (holes) are formed within the recesses between the adjacent protrusions 132.

[0076] As shown in FIG. 15(B), on the other surface 13Y side of the drainage plate 13 (specifically, the surface side that contacts or is close to the waterproofing material 100), rib-shaped convex portions 134 extending in a second direction perpendicular to the first direction are formed so as to protrude toward the other side (toward the waterproofing material 100). The second direction is, for example, the vertical direction or a direction along the vertical direction. The multiple convex portions 134 extend parallel to each other. A recess is formed between two adjacent convex portions 134 among the multiple convex portions 134.

[0077] As shown in Figures 14 and 17, the waterproofing material 100 covers a plate-shaped body 11A (metal plate). The waterproofing material 100 is sandwiched between the plate surface of the plate-shaped body 11A (metal plate) and the other side 13Y (the side in contact with or adjacent to the waterproofing material 100) of the drainage plate 13, so that the plate-shaped body 11A, the drainage plate 13, and the waterproofing material 100 overlap. The surface 100Z (the surface of the resin material) of the waterproofing material 100 faces the drainage plate 13, so that liquid passing from the one side 13X of the drainage plate 13 to the other side 13Y is received by the surface of the waterproofing material 100. In Figure 17, the flow of liquid is conceptually indicated by arrows. The liquid that passes through the drainage plate 13 toward the waterproofing material 100 flows downward between the surface 100Z of the waterproofing material 100 and the other side 13Y.

[0078] As shown in FIG. 17 , the other surface 13Y of the drainage plate 13 is an uneven surface having a convex surface that is convex toward the waterproofing material 100 and a concave surface that is concave toward the opposite side of the waterproofing material 100. In the examples of FIGS. 15 and 17 , a concave surface is formed between adjacent convex portions 134 of the multiple convex portions 134, and the surfaces of the convex portions 134 are configured as convex surfaces. In this drainage plate 13, liquid passing from the one surface 13X to the other surface 13Y flows downward through at least the gap between the concave surface and the surface 100Z. Furthermore, between the drainage plate 13 and the waterproofing material 100, a gap is also formed between the end surface 134A of the multiple convex portions 134 facing the waterproofing material 100 and the surface 100Z, allowing liquid to flow downward through this gap. The multiple convex portions 134 provided on the other surface 13Y are configured to extend vertically, and the recesses formed between the multiple convex portions 134 are configured as grooves extending vertically. Therefore, the liquid that moves from the one surface 13X side to the other surface 13Y side and enters the recesses between the plurality of protrusions 134 is likely to flow downward through the recesses due to gravity.

[0079] The peripheral convex portion 14 shown in Figures 6, 9, 12, 13, etc. corresponds to an example of a frame portion. The peripheral convex portion 14 is configured in an annular shape and is configured to be overlaid on and fixed to the plate-like body 11A. As shown in Figures 12 and 13, the peripheral portion of the drainage plate 13 and the peripheral portion of the waterproofing material 100 are sandwiched between the plate-like body 11A and the peripheral convex portion 14. When a solid-liquid mixture is poured as shown in Figure 7, the liquid of the solid-liquid mixture that has entered the inside of the peripheral convex portion 14 flows through the drainage plate 13 toward the waterproofing material 100 as shown in Figure 17.

[0080] The plate-shaped body 11A (plate portion) formed as a metal plate is provided with a drainage channel 28. The drainage channel 28 communicates with the inter-component space 140 (FIG. 17) between the drainage plate 13 and the waterproofing material 100 and the space outside the filter plate 10, and serves as a flow path for draining liquid that has entered the inter-component space 140 to the external space. As shown in FIG. 17, the inter-component space 140 includes the space between adjacent convex portions 134, and also includes the space between the end face 134A of the convex portion 134 and the surface 100Z of the waterproofing material 100. The drainage channel 28 has a groove. As shown in FIG. 14, at least a portion of the groove constituting the drainage channel 28 is open to face the drainage plate 13 in the inner region of the peripheral convex portion 14 (the region closer to the center than the inner edge of the peripheral convex portion 14). In this open, opposing portion, liquid that has passed through the drainage plate 13 flows directly into the drainage channel 28. At least the spaces between the members communicate with the grooves of the drainage channels 28. An anti-corrosion layer made of a non-metallic material is provided on the inner walls (inner walls of the grooves) of the drainage channels 28. The anti-corrosion layer is, for example, a resin layer made of a resin material.

[0081] In the examples of Figures 13 and 14, the waterproofing material 100 is arranged in a region inside the peripheral convex portion 14 (frame portion) to avoid the drainage channel 28 (groove portion). That is, the waterproofing material 100 is arranged in a region of the plate surface of the plate-like body 11A that is away from the drainage channel 28. The waterproofing material 100 has a notch-shaped or hole-shaped opening 100C formed therein. The space inside the opening 100C and the drainage channel 28 (groove portion) are connected in the region inside the peripheral convex portion 14 (frame portion). In the region where the opening 100C is provided, liquid that has passed through the drainage plate 13 passes through the opening 100C and flows directly into the drainage channel 28. The opening 100C is connected to the inter-component space 140 described above, and liquid flowing through the inter-component space 140 can pass through the opening 100C and flow into the drainage channel 28.

[0082] The dehydrated cake 7A discharged as described above using the filter press apparatus 1 can be used as the product obtained in the production step.

[0083] 1-3. Preparation process In the preparation step, a powder or granular material containing at least one of dust and a filler is prepared as a mixture. Specifically, a collection step is performed in which the powder or granular material containing at least one of dust and a filler is collected using a dust collector, and the collected powder or granular material is used as a mixture. In the following example, crushed stone dust is used as a representative example of the mixture, but other types of dust such as lime dust or a filler may also be used.

[0084] The preparation process may include, for example, a collection process in which stones or rocks (e.g., boulders) are crushed to generate crushed stone dust. In this case, the collection process may mainly include a crushing process and an extraction process. In this example, the crushing process is a process in which stones or rocks are crushed using a known method. In the crushing process, for example, rocks or stones (e.g., rock formations) are crushed using a crusher (crushing machine) in a quarry or the like to generate crushed stone, thereby generating crushed stone dust. Note that the method for crushing stones or rocks (i.e., the method for generating crushed stone and crushed stone dust) is not limited to this example, and various other known methods can be used as long as they are capable of crushing rocks or stones to generate crushed stone and crushed stone dust.

[0085] The extraction process is a process of extracting crushed stone dust from the crushed material produced in the crushing process to be used in the final soil (soil solidification material or soil other than soil solidification material). In the extraction process, some or all of the crushed material (crushed stone or crushed stone dust) produced by crushing using a crushing means such as a crusher is treated as a sorting target, and crushed stone dust is extracted from this sorting target. The crushed stone dust extraction method, for example, involves removing relatively large crushed stones and foreign objects from the crushed material (crushed stone or crushed stone dust) and collecting the remaining crushed stone dust or filler using a dust collector.

[0086] The crushed stone dust thus obtained may function as a main component of the final soil (e.g., soil solidification material), or as a component other than the main component. This crushed stone dust is a collection of fine stones, a granular material, that is generated when large stones (e.g., boulders) are crushed to produce crushed stone. Crushed stone dust is, for example, a collection of minute stones that is generated when crushing stones to obtain crushed stone of a predetermined size (specifically, a size of 5 mm or more). Crushed stone dust is generally material that is partially or entirely discarded or that is likely to become discarded. Crushed stone dust is formed incidentally, for example, when crushed stone is produced by mechanical processing only without chemical processing. Note that no chemical processing is required at all during the process of crushing stones to obtain crushed stone dust, but some chemical processing may be performed.

[0087] The particle size of the crushed stone dust prepared in the preparation process is, for example, greater than 0 mm and less than 5 mm. This crushed stone dust is formed, for example, when rock is crushed in a quarry using a crusher to produce crushed stone. The particle size of the crushed stone dust here refers to the size of the sieve openings when the crushed stone dust particles are separated by sieving. For example, crushed stone dust with a particle size of less than 5 mm refers to crushed stone dust that passes through a sieve with a 5 mm opening, and crushed stone dust with a particle size of 5 mm or more refers to crushed stone dust that does not pass through a sieve with a 5 mm opening. The mixture prepared in the preparation process may consist of crushed stone dust alone, or may be a mixture of crushed stone dust and other powders and granular materials. For example, the mixture prepared in the preparation process may contain lime, gypsum, and crushed stone dust. In this case, when the total of lime, gypsum, and crushed stone dust is taken as 100% by weight, the content of crushed stone dust with a particle size of less than 5 mm is preferably 50% by weight or more but less than 100% by weight, more preferably 50% by weight or more but less than 70% by weight. Even more preferably, when the total of lime, gypsum, and crushed stone dust is taken as 100% by weight, the content of crushed stone dust with a particle size of less than 3 mm is preferably 50% by weight or more but less than 100% by weight, more preferably 50% by weight or more but less than 70% by weight.

[0088] Thus, the soil (e.g., soil solidification material) produced in this embodiment contains crushed stone dust generated when crushing stones to produce crushed stone, allowing for effective utilization of the crushed stone dust that would otherwise be waste material. Crushed stone dust is a powder produced from large stones (e.g., rocks found in nature) when processing these stones. Unlike cement-based solidification materials (solidification materials containing a large amount of cement), it is unlikely for large amounts of chemical substances to remain in the soil, reducing the burden on the environment. Furthermore, crushed stone dust does not require chemical processing, as is the case with the preparation of cement-based solidification materials, reducing the effort required for preparation. Therefore, the soil (e.g., soil solidification material) produced in this first embodiment allows for effective utilization of waste material, reducing the burden on the environment, and enabling low-cost solidification processing.

[0089] 1-4.Mixing process In the mixing step, the mixture prepared in the preparation step (e.g., crushed stone dust) is mixed with the dehydrated cake obtained in the production step to produce mixed soil. The mixed soil may be mixed with soil to function as a soil solidification material, or the mixed soil itself may be used as soil without being mixed with soil. When the mixed soil is used as a soil solidification material, it is stored in a bag or the like with an adjusted composition, for example.

[0090] According to this soil production method, soil can be produced by incorporating dehydrated cake obtained during the solid-liquid mixture treatment process and crushed stone dust generated when crushing rocks to produce crushed stone. This allows for the effective use of dehydrated cake and crushed stone dust, which tend to become waste materials. Furthermore, crushed stone dust is a material generated from rocks, and there is no concern that large amounts of chemical substances will remain in the soil, as with cement-based solidification materials (solidification materials containing a large amount of cement), thereby further reducing the burden on the environment. Furthermore, crushed stone dust requires little or no chemical processing, as with the preparation of cement-based solidification materials, thereby reducing the effort required for preparation. Therefore, according to the soil production method of the first embodiment, crushed stone dust, which tends to become waste material in part or in whole, can be effectively utilized, allowing for solidification processing to be performed at low cost while reducing the burden on the environment.

[0091] 1-5.Drying process After the above-described generating step and before the mixing step, a drying step may be performed to dry the dehydrated cake generated in the generating step. In this case, the dehydrated cake dried in the drying step may be mixed with the mixture prepared in the preparation step in the mixing step. When drying the dehydrated cake in this manner in the drying step, a drying device that directly heats the dehydrated cake or heats the dehydrated cake by supplying hot or cold air to the dehydrated cake may be used, or other drying devices may be used. Alternatively, in the drying step, the dehydrated cake may be dried by leaving it indoors or outdoors to reduce its moisture content to a certain level. In the drying step, the moisture content of the dehydrated cake is preferably reduced to 50% or less, more preferably 30% or less, and even more preferably 20% or less. After the mixing step, the soil obtained by mixing the mixture with the dehydrated cake may be dried in the same manner as in the above-described drying step.

[0092] 1-6. How to reuse soil The soil production method described above can be used to realize a method for reusing soil. For example, as shown in FIG. 18 , a solid-liquid mixture such as muddy water generated at a construction site such as a dam or tunnel is collected and stored in a storage container. A known thickener or the like can be used as the storage container. Then, the above-described production step is performed. Specifically, the solid-liquid mixture 7 stored in the storage container is supplied to a filter press device 1, and the solid-liquid mixture 7 is dehydrated by squeezing using the filter press device 1 to produce a dehydrated cake 7A. In this way, in the reuse method, the production step is performed by dehydrating the solid-liquid mixture generated at the construction site using the filter press device 1 to produce a dehydrated cake 7A.

[0093] In this reuse method, a preparation step similar to that in the soil manufacturing method described above is performed to prepare powder and granular material as a mixture to be mixed with the dewatered cake 7A. In the preparation step, as in the preparation step described above, powder and granular material 150, which is at least one of crushed stone dust, lime dust, and fine aggregate, or powder and granular material obtained by crushing rock, is prepared as a mixture to be mixed in the mixing step described below. Note that, as the powder and granular material 150, granular material containing granular sand or granular material containing granular sand may be used instead of or in addition to the powder and granular material described above. The powder and granular material 150 may also contain lime, gypsum, etc.

[0094] In this reuse method, after the generation step and preparation step, a mixing step similar to that in the soil manufacturing method described above is performed, in which the dehydrated cake 7A generated in the generation step is mixed with the mixture prepared in the preparation step (the above-mentioned powder and granular material 150) to generate mixed soil 160.

[0095] In the reuse method, an arrangement step is performed in which the mixed soil 160 produced in the mixing step is arranged as soil at or around the construction site. The mixed soil 160 may be mixed with other soils to function as a soil solidification material to solidify the other soils, or may simply be used mixed with other soils, or may be used without being mixed with other soils. In either case, by placing soil containing the mixed soil 160 as soil at or around the construction site, the soil can be effectively utilized at the location where it is arranged. In this case, the location may be solidified, the watertightness may be increased, or it may be used as soil in which plants can grow. In this way, the soil contained in the solid-liquid mixture produced at the construction site is reused as soil near the construction site.

[0096] 1-7.Example of effects The above-described manufacturing method can produce a soil solidification material by utilizing the solid-liquid mixture.

[0097] Furthermore, in the above-described production method, by utilizing a filter press apparatus having a waterproof material, the liquid contained in the solid-liquid mixture can be smoothly discharged when the solid-liquid mixture is dehydrated, and a dehydrated cake with an even lower moisture content can be produced.

[0098] Furthermore, in the above-mentioned manufacturing method, when the filter plate portion and the contact portion are close to each other, the first seal portion and the second seal portion press against each other to form a sealing portion, resulting in a strong sealing structure and enabling the pressure inside the filter chamber to be further increased during dehydration.

[0099] The filter plate 10 includes a plate-shaped body 11A (plate portion) and a drainage plate 13 (covering portion) arranged overlapping the plate-shaped body 11A, and is configured as a filter plate for a filter press device that receives a solid-liquid mixture and discharges liquid from the solid-liquid mixture. The filter plate 10 includes a waterproof material 100 made of a waterproof plate or waterproof sheet material and configured to be thinner than the plate-shaped body 11A (plate portion). The drainage plate 13 has a water-passing portion formed therein that allows liquid to pass from one side of the drainage plate 13 to the other side. The waterproof material 100 is sandwiched between the plate surface of the plate-shaped body 11A and the other side of the drainage plate 13, and the plate-shaped body 11A, the drainage plate 13, and the waterproof material 100 overlap.

[0100] This filter plate 10 has a configuration in which the waterproofing material 100 is sandwiched between the plate surface of the plate-like body 11A and the other surface of the drainage plate 13. Because the plate-like body 11A, the drainage plate 13, and the waterproofing material 100 overlap, it is possible to prevent the liquid contained in the solid-liquid mixture from directly hitting the plate surface of the plate-like body 11A. This prevents deterioration of the plate surface of the plate-like body 11A due to the liquid, and also prevents a decrease in the dischargeability of the drainage plate 13 due to deterioration of the plate surface. Therefore, this filter plate 10 can smoothly discharge the liquid contained in the solid-liquid mixture when dehydrating the solid-liquid mixture in the filter press device 1.

[0101] The filter plate 10 is configured so that liquid flows between the surface of the waterproof material 100 and the other side. This filter plate 10 allows liquid to flow between the surface of the waterproof material 100 and the other side of the drainage plate 13, so that the liquid can be effectively drained while preventing the liquid from hitting the plate-like body 11A.

[0102] In the filter plate 10, the other side of the drainage plate 13 is an uneven surface having a convex surface that is convex toward the waterproofing material 100 and a concave surface that is concave toward the opposite side of the waterproofing material 100. In the filter plate 10, the other side of the drainage plate 13 (the surface facing the waterproofing material 100) is an uneven surface, so that the other side of the drainage plate 13 can be prevented from coming into close contact with the waterproofing material 100 as a whole. Therefore, the filter plate 10 prevents a decrease in drainage performance caused by the other side coming into close contact as a whole, and further improves drainage performance.

[0103] The drainage plate 13 is formed in a plate shape and has holes formed therethrough in the plate thickness direction. This filter plate 10 allows the waterproof material 100 to be compactly and stably sandwiched between the plate-shaped drainage plate 13 and the plate-shaped body 11A.

[0104] In the filter plate 10, the drainage plate 13 is made of a resin material, the waterproofing material 100 is made of a resin sheet, and the plate-like body 11A is made of a metal material. This filter plate 10 can be configured to increase the strength of the plate-like body 11A, make the plate-like body 11A rust-resistant, and make it difficult for the rust of the plate-like body 11A to affect the drainage plate 13.

[0105] The filter plate 10 is provided with peripheral convex portions 14A and 14B as a frame portion. The peripheral convex portions 14A and 14B are configured to be annular and are configured to be overlapped on and fixed to the plate-like body 11A. The peripheral portion of the drainage plate 13 and the peripheral portion of the waterproofing material 100 are sandwiched between the plate-like body 11A and the frame portion (either peripheral convex portion 14A or 14B), and liquid of the solid-liquid mixture that has entered the inside of the peripheral convex portions 14A and 14B flows through the drainage plate 13 toward the waterproofing material 100. This filter plate 10 can be held by the peripheral convex portions 14A and 14B and the plate-like body 11A so that the peripheral portions of the drainage plate 13 and the waterproofing material 100 are sandwiched between them. Therefore, a configuration is realized in which the inner edge of the peripheral side protrusions 14A, 14B can guide liquid toward the drainage plate 13, while the peripheral side protrusions 14A, 14B can also be used to hold the drainage plate 13 and the waterproof material 100.

[0106] The filter plate 10 has a drainage channel 28 that communicates with the inter-component space between the drainage plate 13 and the waterproofing material 100 and the space outside the filter plate 10, and the drainage channel 28 is a flow path for flowing liquid from the inter-component space to the external space. This filter plate 10 achieves a configuration that improves drainage by the waterproofing material 100, and can efficiently discharge liquid guided by the waterproofing material 100 and the drainage plate 13 to the outside of the filter plate 10 by the drainage channel 28.

[0107] Second Embodiment Figures 19 and 20 show a portion of a filter plate 10 according to the second embodiment. The filter plate 10 according to the second embodiment differs from the filter plate 10 according to the first embodiment only in the shape of the waterproof material 100, and is otherwise identical to the filter plate 10 according to the first embodiment. The waterproof material 100 of the filter plate 10 according to the second embodiment differs from the waterproof material 100 of the filter plate 10 according to the first embodiment in that the waterproof material 100 is provided so as to cover the drainage channel 28 (groove portion) in the area inside the peripheral side convex portion 14 (the area of ​​the open portion 100C is also provided with the waterproof material 100), and is otherwise identical to the waterproof material 100 of the filter plate 10 according to the first embodiment. A filter press device in which the filter plate 10 according to the second embodiment is provided is identical to the filter press device 1 according to the first embodiment, except for the waterproof material 100.

[0108] In the filter plate 10 of the second embodiment, the peripheral edge of the drainage plate 13 (covering portion) and the peripheral edge of the waterproofing material 100 are sandwiched between the plate-shaped body 11A (plate portion) and the peripheral convex portion 14 (frame portion). When the liquid of the solid-liquid mixture penetrates the inside of the peripheral convex portion 14, as in FIG. 7, it flows through the drainage plate 13 toward the waterproofing material 100. The plate-shaped body 11A is provided with a drainage channel 28 that connects the inter-component space between the drainage plate 13 and the waterproofing material 100 (the inter-component space similar to the inter-component space 140 in FIG. 17) to the space outside the filter plate 10, and serves as a flow path for discharging liquid that has penetrated into the inter-component space to the external space. The waterproofing material 100 directs the liquid along the surface 100Z toward the area outside the inner edge of the peripheral convex portion 14. In this configuration, as shown by the arrows in Figure 20, liquid flows from the waterproofing material 100 to the drainage channel 28 between the peripheral edge protrusion 14 and the plate-shaped body 11A, outside the inner edge of the peripheral edge protrusion 14.

[0109] <Other embodiments> The present disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of features of the above-described or following embodiments is possible within a range that does not contradict. Furthermore, any feature of the above-described or following embodiments may be omitted unless explicitly stated as essential. Furthermore, the above-described embodiment may be modified as follows.

[0110] In the above embodiment, an example of a solid-liquid mixture was described, but the solid-liquid mixture may be one other than the above example, and may be a mixture of at least a liquid and a solid (for example, at least one of a powder, granular material, powder, and granular material).

[0111] In the above-described embodiment, crushed stone dust is used as an example of the mixture. However, other powders and granules such as lime dust and fine aggregate may also be used, or powders and granules obtained by crushing rocks such as granite. Alternatively, powders and granules that are granular sand themselves or powders and granules containing a predetermined proportion of granular sand may also be used. For example, when dismantling and disposing of gravestones, the gravestones may be crushed, and the powders and granules obtained by crushing the gravestones may be prepared as the above-described mixture and mixed with the dehydrated cake. Alternatively, two or more of crushed stone dust, lime dust, powders and granules obtained by crushing other rocks, and other fine aggregates may be used as a mixture.

[0112] In the above-described embodiment, the plate-like body 11A, which corresponds to an example of the plate portion, is made of only one metal plate material, but it may be made of a plurality of stacked metal plates, or may be made of a metal plate material to which some metal member or non-metal member (such as a resin member or a ceramic member) is fixed. The plate portion may have other configurations as long as it is made of a material that is not desirable to come into contact with liquid or that should be avoided.

[0113] In the above embodiment, the filter plate 10 has a rectangular shape when viewed from the front, but the shape of the filter plate is not limited to a rectangular shape when viewed from the front. The shape of the outer edge of the filter plate may be a polygon other than a rectangle, may be a partially or entirely curved outer edge, or may have other shapes.

[0114] In the above-described embodiment, the filter plate group 5 is configured with a plurality of filter plates 10 arranged in a row, but any configuration may be used as long as a filter chamber is formed inside the filter plate group 5. For example, the filter press device may be equipped with two or more types of filter plates, or may be configured with a frame interposed between the filter plates. In this case, the filter plates can function as filter plate portions, and the frame can function as a contact portion.

[0115] In the above-described embodiment, the filter plate structure 3 is provided with an annular protrusion 24 and an annular recess 34, and when multiple filter plates 10 are closely attached, the annular protrusion 24 fits into the annular recess 34. However, this configuration is not limited to this. For example, the position of the annular protrusion 24 may be a flat surface similar to the first pressing surface 22. That is, the annular protrusion 24 may not exist, and the first pressing surface 22 may extend to the position of the annular protrusion 24. Similarly, the position of the annular recess 34 may be a flat surface similar to the second pressing surface 32. That is, the annular recess 34 may not exist, and the second pressing surface 32 may extend to the position of the annular recess 34.

[0116] In the above-described embodiment, each filter plate 10 constituting the filter plate structure 3 has an annular protrusion 24 and an annular recess 34. However, the annular protrusion 24 may be configured as a first annular recess having a protrusion protruding from the first pressing surface 22 and a recess recessed from the first pressing surface 22, or the annular recess 34 may be configured as a second annular recess having a protrusion protruding from the second pressing surface 32 and a recess recessed from the second pressing surface 32. For example, the first annular recess may be configured as an annular recess around the center recess 12A, with the recesses and protrusions alternately arranged in the circumferential direction. Similarly, the second annular recess may be configured as annular recess around the center recess 12B, with the recesses and protrusions alternately arranged in the circumferential direction. In this case, the filter plate structure may have a sealing structure in which, when adjacent filter plates 10 are brought into close contact, the convex portions of the first annular uneven portion enter into the concave portions of the second annular uneven portion and press against the concave portions, and the convex portions of the second annular uneven portion enter into the concave portions of the first annular uneven portion and press against the concave portions.

[0117] In the above-described embodiment, a resin plate or sheet material is exemplified as an example of a plate or sheet material made of a non-metallic material that constitutes the waterproofing material, but this is not limiting. For example, the waterproofing material may be made of a ceramic sheet or plate. The waterproofing material may also be a waterproof layer laminated on the plate surface of the plate-shaped body 11A (plate portion).

[0118] In the above-described embodiment, it is desirable that the drainage plate 13 or the drainage plate 113 is made of a resin material, but the drainage plate 13 or the drainage plate 113 may also be made of a non-metallic material other than a resin material (for example, a ceramic material).

[0119] In the above-described embodiment, the drainage channel 28 is provided in the plate-shaped body 11A (plate portion), but it does not have to be provided in the plate portion as long as it is configured to communicate with the inter-component space between the covering portion and the waterproofing material and the space outside the filter plate. For example, a pipe continuing from the inter-component space to the outside of the filter plate may be arranged so as to pass through the inside of the frame portion or the plate-shaped body.

[0120] In the above-described embodiment, the drainage plate 13 is exemplified as an example of the covering portion, but the covering portion is not limited to the configuration of the drainage plate 13. For example, as shown in Figures 21(A) and 21(B), a drainage plate 113 having a resin plate 190 of a predetermined thickness and a large number of through holes 198 formed therethrough in the plate thickness direction may be used instead of the drainage plate 13. The resin plate 190 has one plate surface 190A configured flat and the other plate surface 190B configured flat.

[0121] In the manufacturing method according to the embodiment described above, the soil solidification material is manufactured by mixing the dehydrated cake with a mixture containing powder and granular material, but other substances may be contained in addition to the dehydrated cake and the powder and granular material. For example, the soil solidification material may be manufactured by mixing lime and gypsum in addition to the dehydrated cake and the powder and granular material.

[0122] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0123] 1: Filter press equipment 7 :Solid-liquid mixture 7A: Dehydrated cake 10:Filter plate 11A: Plate-shaped body (plate portion) 13: Drainage plate (covering part) 14: Peripheral convex part (frame part) 28:Drainage channel 100: Waterproof material 100C: Open part 100Z: Surface 113: Drainage plate (covering part) 132: Convex part 134: Convex part 134A: End face 138: Water flow section 150: Powder 160: Mixed soil 140: Space between components 198: Through hole (water passage part)

Claims

1. a generating step of dewatering the solid-liquid mixture using a filter press device to generate a dewatered cake; a collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the dehydrated cake produced in the producing step with the powder or granular material collected in the collecting step; A method for producing soil, comprising:

2. a collecting step of collecting powder and granular material containing at least one of dust and filler with a dust collector; a mixing step of mixing the powder and granular material collected in the collecting step with lime and gypsum; A method for producing soil, comprising:

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