Manufacturing method of filter media

Abstract

To provide a filter medium capable of stably performing solid-liquid separation in comparison with a case using a conventional filter medium.SOLUTION: A filter medium separates a liquid from a solid-liquid mixed raw material. The filter medium has a planar filter medium body having a surface at a side being in contact with the solid-liquid mixed raw material and a rear surface at the opposite side of the surface. A plurality of work parts for deliquoring are formed at the filter medium body. Each of the plurality of work parts for deliquoring is sandwiched by two shear portions. In the two shear portions, the filter medium body is sheared between the surface and the rear surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a filter medium used to separate liquids and solids from a solid-liquid mixed material in which liquids and solids are mixed, such as sludge, and a method for manufacturing the filter medium. [Background technology]

[0002] Patent Document 1 discloses a screw deliquor. In this type of screw deliquor, a filter medium is arranged to cover the inner peripheral surface of a barrel (filter tube) during use. For example, a filter cloth with many pores formed therein, or a metal plate with many slits formed therein, is used as the filter medium. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-212697 A Summary of the Invention [Problem to be solved by the invention]

[0004] When a filter cloth with many pores or a metal plate with many slits is used as a filter medium, if the raw material to be filtered contains very fine solids, some of the very fine solids may pass through the pores (or slits) of the filter medium together with the liquid and be discharged. In that case, there is a risk that solid-liquid separation cannot be performed sufficiently.

[0005] The present specification provides a filter medium that can perform solid-liquid separation more stably than when conventional filter media are used. [Means for solving the problem]

[0006] The filter medium disclosed in this specification is a filter medium that separates liquid from a solid-liquid mixed raw material. The filter medium has a planar filter medium body having a surface on the side that contacts the solid-liquid mixed raw material and a back surface on the opposite side to the surface. A large number of drainage processing parts are formed on the filter medium body. Each of the large number of drainage processing parts is sandwiched between two shear parts. The two shear parts are the parts where the filter medium body is sheared between the surface and the back surface.

[0007] When the solid-liquid mixed raw material is filtered using the above filter medium, the solid-liquid mixed raw material is arranged so as to contact the front side of the filter medium body. As the solid-liquid mixed raw material contacts the front side of the filter medium body, the liquid of the solid-liquid mixed raw material is discharged to the back side through two shearing parts that sandwich the liquid removal processing part. The shearing part is a part where the filter medium body is sheared between the front side and the back side. Therefore, unlike conventional filter mediums in which a large number of fine pores or slits are formed, this filter medium has almost no gaps in the longitudinal and width directions of the filter medium body. Therefore, the liquid contained in the solid-liquid mixed raw material introduced to the front side of the above filter medium is discharged to the back side through the extremely small gaps formed by the shearing part. That is, even if the solid-liquid mixed raw material contains fine particulate solids, the shearing part can capture such solids without passing them through. According to the above filter medium, even if the solid-liquid mixed raw material contains fine particulate solids, solid-liquid separation can be performed stably.

[0008] The solid-liquid mixed raw material may be transported on the surface in a predetermined transport direction. The two shear portions may be formed along the transport direction.

[0009] According to this configuration, as the solid-liquid mixed raw material is transported along the transport direction, the liquid contained in the solid-liquid mixed raw material is discharged to the back side through the two shearing sections that sandwich the liquid removal processing section. The solid-liquid separation can be stably performed while the solid-liquid mixed raw material is transported along the transport direction.

[0010] The multiple drainage processed portions may be formed flush with the filter medium body.

[0011] According to this configuration, there is no vertical cavity (vertical hole) that opens along the thickness direction of the filter body on both sides of the liquid removal processing section. The gaps provided in the filter are only very small gaps formed by the shearing section. Therefore, even if the solid contained in the solid-liquid mixed raw material fed into the filter medium is in the form of very fine particles, it can be captured without passing through the shearing section. According to this configuration, even if the solid-liquid mixed raw material contains very fine particulate solids, solid-liquid separation can be performed sufficiently.

[0012] The surface of each of the plurality of drainage processed portions may be recessed from the surface of the filter body. The back surface of each of the plurality of drainage processed portions may protrude from the back surface of the filter body.

[0013] According to this configuration, vertical cavities (vertical holes) that open along the thickness direction of the filter body can be formed on both sides of the liquid removal processing section. When vertical holes are formed on both sides of the liquid removal processing section, the liquid contained in the solid-liquid mixed raw material is discharged through the gaps and vertical holes of the shearing section. When the solids contained in the solid-liquid mixed raw material fed into the filter medium are in the form of relatively large particles, the solids can be captured without passing through the shearing section and the vertical holes. According to this configuration, even when the solid-liquid mixed raw material contains relatively large particulate solids, solid-liquid separation can be sufficiently performed.

[0014] The multiple drainage processed portions may be arranged in a staggered pattern.

[0015] In this configuration, the contact area between the solid-liquid mixture and the liquid-removing processed section is wider than that in the case where multiple liquid-removing processed sections are arranged in parallel, and the liquid-removing ability is high. Also, the strength is high when the solid-liquid mixture is pressed against the filtration surface to squeeze out the liquid.

[0016] The filter medium body may be formed in a cylindrical shape.

[0017] According to this configuration, the filter material can be used as a filter material when a solid-liquid mixed raw material is pressed against the filtering surface to squeeze out the liquid, for example, as a barrel filter material that is placed on the inner surface of the barrel of a screw-type or helical-type deliquor machine.

[0018] The manufacturing method of the filter medium disclosed in this specification is a manufacturing method of the filter medium that separates liquid from the solid-liquid mixed raw material. This manufacturing method includes a processing step of forming a number of drainage processing parts by pressing and punching a number of parts of a planar filter medium body having a surface that contacts the solid-liquid mixed raw material and a back surface opposite to the surface in the thickness direction. Each of the many drainage processing parts is sandwiched between two shearing parts. The two shearing parts are the parts where the filter medium body is sheared between the surface and the back surface by the press.

[0019] According to this method, the above-mentioned filter medium disclosed in this specification can be formed. By punching the filter medium body by press processing, the drainage processing part and the shearing part can be formed. Therefore, compared with the conventional filter medium manufacturing method in which slits are formed by laser cutting (or wire cutting) a metal plate, the processing time and processing cost can be significantly reduced.

[0020] The shearing part that sandwiches a number of drainage processing parts formed by the above method is the part where the filter body is sheared between the front surface and the back surface.Therefore, it is possible to form a filter body that has almost no gap in the width direction and the length direction of the filter body.Therefore, even if the solid-liquid mixed raw material contains fine particulate solid, it is possible to manufacture a filter medium that can sufficiently perform solid-liquid separation.

[0021] The solid-liquid mixed raw material may be transported on the surface in a predetermined transport direction. The two shear portions may be formed along the transport direction.

[0022] According to the filter medium manufactured by this method, as the solid-liquid mixed raw material is transported along the transport direction, the liquid contained in the solid-liquid mixed raw material is discharged to the back side through the two shearing parts that sandwich the liquid removal processing part. The solid-liquid mixed raw material can be stably separated into solid and liquid while being transported along the transport direction.

[0023] The method may further include, after the processing step, a push-back step of pushing back the multiple processed parts for liquid removal by pressing the multiple processed parts for liquid removal in a direction opposite to a pressing direction in the processing direction.

[0024] According to this method, even if vertical cavities (vertical holes) that open along the thickness direction of the filter body are formed on both sides of the dehydration processing section by pressing in the processing step, the opening width of the vertical holes can be adjusted to a desired value by pressing in the opposite direction in the push-back step. Also, by adjusting the amount of pressing in the push-back step, the vertical holes can be eliminated. Depending on the characteristics of the raw material to be filtered, the presence or absence of vertical holes and the opening width when vertical holes are provided can be adjusted.

[0025] The plurality of drainage processed portions after the pushing back step may be formed flush with the filter medium body.

[0026] According to this method, it is possible to manufacture a filter medium in which a large number of drainage processing parts are formed flush with the filter medium body. On both sides of the drainage processing part of the filter medium to be manufactured, there is no vertical cavity (vertical hole) that opens along the thickness direction of the filter medium body. Even if the solid-liquid mixed raw material contains extremely fine particulate solids, it is possible to manufacture a filter medium that can sufficiently perform solid-liquid separation.

[0027] In the processing step, the multiple drainage processed parts may be formed by pressing and punching the multiple locations of the filter body from the front surface to the back surface. The front surface of each of the multiple drainage processed parts may be recessed from the front surface of the filter body, and the back surface of each of the multiple drainage processed parts may protrude from the back surface of the filter body.

[0028] According to this method, a filter medium can be manufactured in which the surface of the processing part for liquid removal is recessed from the surface of the filter medium body, and the back surface of the processing part for liquid removal is protruding from the back surface of the filter medium body. In addition, depending on the deformation amount of the processing part for liquid removal, a filter medium can be manufactured in which a vertical cavity (vertical hole) is provided on both sides of the processing part for liquid removal, opening along the thickness direction of the filter medium body. Since the liquid contained in the solid-liquid mixed raw material is discharged through the vertical hole formed in the thickness direction of the shearing part, if the solid contained in the solid-liquid mixed raw material inputted into the filter medium is in the form of slightly large particles, the solid can be captured without passing through the shearing part and the vertical hole. Even if the solid-liquid mixed raw material contains a slightly large particulate solid, a filter medium that can perform solid-liquid separation sufficiently can be manufactured.

[0029] In the processing step, the multiple staggered portions of the filter medium body may be pressed in the thickness direction to punch out the multiple drainage processed portions in a staggered arrangement.

[0030] This method makes it possible to produce a filter medium that has higher liquid drainage properties than a filter medium in which multiple drainage processing sections are arranged in parallel, and also has high strength when the solid-liquid mixed raw material is pressed against the filtration surface to squeeze out the liquid.

[0031] The method may further include a forming step of forming the filter medium body into a cylindrical shape after the plurality of drainage processed portions are formed.

[0032] According to this method, it is possible to produce a filter medium for use when a solid-liquid mixed raw material is pressed against a filtering surface to squeeze out the liquid, such as a barrel filter medium that is placed on the inner surface of the barrel of a screw-type or helical-type deliquor machine. [Brief description of the drawings]

[0033] [Figure 1] FIG. 2 is a plan view showing the filter medium of the first embodiment. [Diagram 2] FIG. 2 is a front view of the filter element of FIG. 1. [Diagram 3] FIG. 3 is a cross-sectional view of the filter medium shown in FIG. 1 along line III-III. [Figure 4] FIG. 2 is a schematic perspective view showing an example in which the filter medium of FIG. 1 is used in the barrel of a screw deliquor machine. [Diagram 5] FIG. 7 is a plan view showing a filter medium according to a second embodiment. [Figure 6] FIG. 6 is a front view of the filter element of FIG. 5 . [Figure 7] 7 is a cross-sectional view showing the VII-VII section of the filter medium of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] (First Example) A filter medium 2 of a first embodiment will be described with reference to Figs. 1 to 3. The filter medium 2 of this embodiment shown in Figs. 1 to 3 is a filter medium used to separate liquid and solid from a solid-liquid mixed raw material such as sludge, and separates liquid and solid from the solid-liquid mixed raw material transported in a predetermined direction. Hereinafter, the solid-liquid mixed raw material may be simply called "raw material".

[0035] The filter medium 2 of this embodiment includes a main body 4 formed in a plate shape as a whole. The main body 4 has a front surface 6 which is the surface (i.e., the filtration surface) that comes into contact with the raw material to be filtered, and a back surface 8 which is the surface opposite to the front surface 6. The main body 4 is formed of a metal such as stainless steel, iron, or aluminum.

[0036] A large number of drainage processed parts 10 are formed on the main body 4. The large number of drainage processed parts 10 are formed parallel to one another along the longitudinal direction of the filter medium 2 (the X-axis direction in the figure). The longitudinal direction of the filter medium 2 is the same as the conveying direction of the raw material to be filtered. As shown in FIG. 1, the large number of drainage processed parts 10 are formed in a staggered arrangement.

[0037] Both ends of each drainage processing section 10 in the width direction (Y-axis direction in the figure) are sandwiched by two shearing sections 20. In this embodiment, the two shearing sections 20 are formed along the X-axis direction, which is the conveying direction of the raw material. In this embodiment, the two shearing sections 20 are formed in parallel straight lines. As shown in FIG. 3, each shearing section 20 is a portion where the main body 4 is sheared between the front surface 6 and the back surface 8. As shown in FIGS. 1 and 3, the shearing section 20 has almost no gaps in the width direction and longitudinal direction (X-axis direction and Y-axis direction in the figure) of the main body 4. In the main body 4, only extremely small gaps formed by shearing the main body 4 by the shearing section 20 exist. The width of the gap of the shearing section 20 is, for example, about 10 μm to 100 μm. Since the width of the slits (slits formed by laser cutting or wire cutting) provided in conventional filter media is about 0.3 mm at the narrowest, it can be said that the width of the gap of the shearing section 20 in this embodiment is significantly narrower than conventional ones.

[0038] As will be explained later, the shearing portion 20 and the processed portion for liquid removal 10 are formed by punching out multiple locations of the main body 4 (i.e., the portions corresponding to the processed portion for liquid removal 10) using press processing. In other words, the processed portion for liquid removal 10 is a pressing portion that is pressed during press processing. Both longitudinal ends of the processed portion for liquid removal 10 are not sheared. Both longitudinal ends of the processed portion for liquid removal 10 are joined to the main body 4.

[0039] 2 and 3, in this embodiment, all of the multiple processed parts for liquid removal 10 are formed flush with the main body 4. As will be described later, after forming the processed parts for liquid removal 10 and the shearing parts 20 by press working, the processed parts for liquid removal 10 are pressed back from the opposite side by press working, thereby forming the processed parts for liquid removal 10 flush with the main body 4.

[0040] (Method of manufacturing filter medium 2) A method for producing the filter medium 2 of this embodiment will be described below. First, a metal body 4 formed into a plate shape is prepared.

[0041] Next, a processing step is performed to form a large number of processed parts for liquid removal 10. In the processing step, a large number of parts of the main body 4 (i.e., parts corresponding to a large number of processed parts for liquid removal 10) are pressed and punched in the thickness direction (Z-axis direction). The pressed parts are arranged in a staggered arrangement. Pressing is performed from the front surface 6 side toward the back surface 8 side. In another example, pressing may be performed from the back surface 8 side toward the front surface 6 side. By punching with a press, a large number of processed parts for liquid removal 10 are formed in the main body 4 in a staggered arrangement. At this time, both sides in the width direction of the pressed part (processed parts for liquid removal 10) of the main body 4 are sheared from the front surface 6 to the back surface 8, and two sheared parts 20 are formed. Both ends in the longitudinal direction are not sheared and are maintained in a state of being joined to the main body 4. At this point, the formed processed parts for liquid removal 10 are recessed in the pressing direction, and vertical cavities (vertical holes) that open along the thickness direction of the main body 4 are present on both sides in the width direction.

[0042] Next, a push-back process is performed. In the push-back process, the numerous processed parts for liquid removal 10 formed are pressed in the opposite direction to the pressing in the above processing process, thereby pushing back the numerous processed parts for liquid removal 10. That is, the numerous processed parts for liquid removal 10 are pushed back from the back surface 8 side toward the front surface 6 side. By being pushed back by the press, the numerous processed parts for liquid removal 10 are formed flush with the main body 4 (see Figures 2 and 3). The vertical holes formed in the processing process disappear. The shearing parts 20 formed on both sides of the processed parts for liquid removal 10 in the width direction remain. The completed shearing parts 20 have almost no gaps in the longitudinal and width directions of the main body 4. The filter medium 2 of this embodiment is obtained by performing each of the above steps.

[0043] The configuration and manufacturing method of the filter medium 2 of this embodiment have been described above. When the filter medium 2 of this embodiment is used to filter raw materials (which may be called deliquification), the raw materials are introduced so as to contact the surface 6 side of the main body 4. When the raw materials come into contact with the surface 6 of the main body 4, the liquid contained in the raw materials is discharged to the back surface 8 side through the two shearing sections 20 that sandwich the liquid-removal processing section 10. As described above, the shearing section 20 of the filter medium 2 of this embodiment is a portion where the main body 4 is sheared between the surface 6 and the back surface 8. Therefore, in the filter medium 2 of this embodiment, unlike conventional filter media in which a large number of pores or slits are formed, there are almost no gaps in the longitudinal and width directions of the main body 4. The liquid contained in the raw materials introduced to the surface 6 side of the main body 4 is discharged to the back surface 8 side through the extremely small gaps formed by the shearing section 20. In other words, even if the raw materials contain fine particulate solids, the shearing section 20 can capture such solids without allowing them to pass through. According to the filter medium 2 of this embodiment, even if the raw materials contain fine particulate solids, solid-liquid separation can be performed stably.

[0044] In addition, in the filter medium 2 of this embodiment, the raw material fed to the surface 6 of the main body 4 is separated into solid and liquid while being transported along a predetermined transport direction on the surface 6. Each shearing section 20 is formed along the transport direction. In the filter medium 2 of this embodiment, the raw material can be stably separated into solid and liquid while being transported.

[0045] In addition, since the gaps between the shearing portions 20 are extremely small and the main body 4 is formed by shearing between the front surface 6 and the back surface 8, clogging of the gaps between the shearing portions 20 is unlikely to occur.

[0046] In addition, the multiple drainage processed sections 10 are formed flush with the main body 4 (see Figures 2 and 3). That is, there are no vertical cavities (vertical holes) that open along the thickness direction of the main body 4 (Z-axis direction in the figure) on both sides of the drainage processed section 10. The only gaps provided in the filter medium 2 are extremely small gaps formed by the shearing section 20. Therefore, even if the solids contained in the raw material fed into the filter medium 2 are extremely fine particles (for example, particles with a diameter of about 0.1 mm), they can be captured without passing through the shearing section 20. Even if the raw material contains extremely fine particulate solids, solid-liquid separation can be performed sufficiently.

[0047] In addition, the draining sections 10 are formed in a staggered arrangement (see FIG. 1). Therefore, the contact area between the raw material and the draining sections 10 is wider than when multiple draining sections 10 are arranged in parallel. While the raw material is transported in the transport direction, the raw material is always in contact with one of the draining sections 10. Therefore, the liquid drainage is higher than when the draining sections 10 are arranged in parallel. Also, the strength is high when the raw material is pressed against the filtration surface to squeeze out the liquid.

[0048] When the filter medium 2 is manufactured by the manufacturing method of this embodiment, the main body 4 is punched out by pressing, thereby forming the liquid-removal processing section 10 and the shearing section 20. Therefore, compared with the conventional filter medium manufacturing method in which a metal plate is laser-cut (or wire-cut) to form slits, the processing time and processing cost can be significantly reduced.

[0049] In addition, since each shearing portion 20 is formed by punching the main body 4 by press processing, there is little variation in the length and width of the gaps between the formed shearing portions 20. Therefore, according to the filter medium 2 formed by the manufacturing method of this embodiment, solid-liquid separation can be performed stably compared to conventional filter cloths, etc., which have a large variation in pore diameter.

[0050] (Typical use of filter media 2) A typical example of the use of the filter medium 2 of this embodiment will be described with reference to FIG. 4. The filter medium 2 of this embodiment can particularly exhibit the above-mentioned effects when used as a filter medium when the raw material is pressed against the surface 6, which is the filtering surface, to squeeze the liquid from the raw material. For example, as shown in FIG. 4, the filter medium 2 can be formed into a cylindrical shape and used as the filter medium 2 arranged on the inner circumferential surface of the barrel 70 of a screw-type or helical body-type deliquor. This type of deliquor has a cylindrical barrel (filter tube) 70, a helical body 80 (or a screw body) arranged in the barrel 70, and a conveying mechanism (not shown) that rotates the helical body 80 to send the raw material introduced into the barrel 70 (more precisely, between the pitches of the helical body 80 in the barrel 70) toward the outlet end 74 of the helical body 80.

[0051] The barrel 70 is a cylindrical member formed into a cylindrical shape by a porous plate such as a punched metal having rigidity. The barrel 70 can be divided into a first barrel member 70a and a second barrel member 70b. The first barrel member 70a and the second barrel member 70b each have a shape obtained by dividing the barrel 70 in half along the axis of the barrel 70. The first barrel member 70a and the second barrel member 70b are combined to form a cylindrical barrel 70 (see FIG. 4). One end of the barrel 70 is an inlet end 72 into which the raw material is introduced, and the other end is an outlet end 74, which is the forward end in the direction of transport of the raw material and from which the cake after deliquor is discharged.

[0052] The helical body 80 has a screw helical member 84 fixed to the outer surface of a rotating shaft 82 arranged concentrically with the barrel 70. The screw helical member 84 is formed so that the pitch interval narrows toward the outlet side. In this embodiment, the screw helical member 84 is a member formed by winding a metal material (metal rod) having a square cross section into a coil. In another example, the screw helical member 84 may be a member formed by winding a metal material having a circular cross section into a coil, or a member formed by winding a metal rod having a cross section of a polygon other than a square (for example, a triangle, a hexagon, etc.) into a coil.

[0053] As shown in Fig. 4, when the filter medium 2 of this embodiment is used in a barrel 70 for this type of deliquor, the filter medium 2 is deformed into a cylindrical shape so that the X-axis direction in Fig. 1 is the axial direction (forming step). At this time, the filter medium 2 is molded so that the front surface 6 that comes into contact with the raw material is the inner peripheral surface, and the back surface 8 is the outer peripheral surface. The filter medium 2 deformed into a cylindrical shape is placed on the inner peripheral surface of the barrel 70 (see Fig. 4). At this time, each shearing section 20 is placed along the longitudinal direction (i.e., the raw material conveying direction).

[0054] When the raw material is deliquified by the deliquifier equipped with the filter medium 2 of this embodiment, the raw material is fed between the pitches of the screw helical member 84. The screw helical member 84 rotates, and the fed raw material is sent toward the outlet end 74. At this time, the pitch interval (i.e., the raw material passage) of the screw helical member 84 gradually narrows toward the outlet end 74, so the raw material is squeezed and deliquified by the inner circumferential surface of the barrel 70 having the filter medium 2 and the rotating shaft 82. As a result, the liquid is separated from the solid-liquid mixed raw material. The separated liquid passes through the extremely small gaps formed by the shearing portion 20 of the filter medium 2 and is discharged from a large number of drainage holes formed in the barrel 70. The raw material from which the liquid has been removed (i.e., the solid matter after deliquification, also called "cake") is discharged to the outside from the outlet end 74.

[0055] (Second Example) The filter medium 102 of the second embodiment will be described with reference to Figures 5 to 7. The filter medium 102 of this embodiment has a basic configuration in common with the filter medium 2 of the first embodiment. In Figures 5 to 7, the same components as those of the first embodiment are indicated by the same reference numerals as those in Figures 1 to 3, and detailed description thereof will be omitted.

[0056] The filter medium 102 of this embodiment is different from that of the first embodiment in the shape of the processed portion for drainage 10. In this embodiment, the surface 16 of each of the many processed portions for drainage 10 is recessed from the surface 6 of the main body 4, and the back surface 18 of each of the many processed portions for drainage 10 protrudes from the back surface 8 of the main body 4. As shown in Figs. 6 and 7, in this embodiment, vertical holes 30, which are vertical cavities that open along the thickness direction of the main body 4, are formed on both sides of the processed portion for drainage 10. The opening width (width in the Z-axis direction) of the vertical holes 30 varies depending on the raw material to be filtered. The opening width of the vertical holes 30 is, for example, any value within the range of 100 μm to 0.5 mm. The opening width of the vertical holes 30 may be any value other than this. On the other hand, as shown in Fig. 5, in this embodiment, the shearing portion 20 has almost no gap in the width direction and longitudinal direction of the main body 4 (X-axis direction and Y-axis direction in the figure). It can be said that the processed portion for drainage 10 of this embodiment is formed in a louver shape with openings on both sides.

[0057] Furthermore, like the filter material 2 of the first embodiment, the filter material 102 of the present embodiment can be formed into a cylindrical shape and used as a filter material to be placed on the inner surface of the barrel 70 of a screw-type or helical-type deliquor machine (see FIG. 4).

[0058] Next, a manufacturing method of the filter medium 102 of this embodiment will be described. This embodiment is different from the first embodiment in that the push-back process is not performed after the processing process is performed. In this embodiment, a processing process for forming a large number of drainage processed parts 10 is performed on a metal body 4 formed in a plate shape. In the processing process, a large number of parts of the body 4 (i.e., parts corresponding to a large number of drainage processed parts 10) are pressed and punched in the thickness direction (Z-axis direction). This forms a large number of drainage processed parts 10. At this time, both sides of the width direction of the drainage processed part 10 of the body 4 are sheared from the front surface 6 to the back surface 8, and two sheared parts 20 are formed. The front surface 16 of the drainage processed part 10 is recessed more than the front surface 6 of the body 4, and the back surface 18 of the drainage processed part 10 protrudes from the back surface 8 of the body 4. On both sides of the width direction of the drainage processed part 10, there are vertical holes 30 that open along the thickness direction of the body 4. By adjusting the amount of pressing in the processing process, the opening width of the vertical hole 30 can be adjusted to a desired value. In this embodiment, the pushing back step is not performed after the processing step is performed. The filter medium 102 of this embodiment is obtained by completing the processing step.

[0059] The configuration and manufacturing method of the filter medium 102 of this embodiment have been described. The filter medium 102 of this embodiment also basically exerts the same effect as the filter medium 2 of the first embodiment. Furthermore, in the filter medium 102 of this embodiment, vertical holes 30 are formed on both sides of the liquid removal processing section 10. Therefore, the liquid contained in the raw material is discharged through the gaps and vertical holes of the shearing section 20. When the solid contained in the raw material input to the filter medium 2 is in the form of slightly large particles (for example, particles of about 0.5 mm to 1 mm), the solid can be captured without passing through the shearing section 20 and the vertical holes 30. According to the filter medium 102 of this embodiment, even if the raw material contains a slightly large particulate solid, solid-liquid separation can be sufficiently performed. In addition, since the liquid can be efficiently discharged from the vertical holes 30, solid-liquid separation can be efficiently performed.

[0060] According to the manufacturing method of the filter medium 102 of this embodiment, the opening width of the vertical hole 30 can be adjusted to a desired value by adjusting the pressing amount. Therefore, the opening width of the vertical hole 30 can be easily adjusted according to the characteristics of the target raw material.

[0061] Although the embodiments of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. For example, the following modifications may be included.

[0062] (Modification 1) In each of the above-mentioned embodiments, the filter medium 2, 102 is formed into a cylindrical shape and used as a filter medium arranged on the inner circumferential surface of the barrel 70 of a screw-type or helical-type deliquor machine. However, the filter medium 2, 102 may be used as it is in a plate shape, or may be deformed into a shape other than a cylindrical shape.

[0063] (Modification 2) In each of the above-mentioned embodiments, the multiple drainage processed parts 10 are formed in a staggered arrangement (see Figs. 1 and 5). However, this is not limited thereto, and the multiple drainage processed parts 10 may be formed in a parallel arrangement.

[0064] (Modification 3) In the manufacturing method of the second embodiment, a push-back step may be performed after the processing step. That is, after the main body 4 is pressed and sheared in the processing step to form a large number of liquid-removal processed parts 10, sheared parts 20, and vertical holes 30, the liquid-removal processed parts 10 may be pressed from the opposite side in the push-back step to adjust the opening width of the vertical holes 30 to a desired value.

[0065] (Variation 3a) In the above variation 3, the vertical hole 30 may be eliminated by pressing the processed part for liquid removal 10 from the opposite side in the push-back process. In this case, the front surface 16 of the processed part for liquid removal 10 is recessed more than the front surface 6 of the main body 4, and the back surface 18 protrudes from the back surface 8 of the main body 4, but the vertical hole 30 is not formed. In this case, the amount of recession of the front surface 16 and the amount of protrusion of the back surface 18 are smaller than the thickness of the main body 4. Whether to eliminate or form the vertical hole 30 may be switched depending on the characteristics of the raw material to be filtered.

[0066] (Variation 4) In the second embodiment, the surface 16 of the processed part for liquid removal 10 is recessed relative to the surface 6 of the main body 4, and the back surface 18 of the processed part for liquid removal 10 protrudes from the back surface 8 of the main body 4. In a variation, on the contrary, the surface 16 of the processed part for liquid removal 10 may protrude relative to the surface 6 of the main body 4, and the back surface 18 of the processed part for liquid removal 10 may be recessed from the back surface 8 of the main body 4. In yet another variation, the protruding directions of some of the multiple processed parts for liquid removal 10 may be different from each other.

[0067] (Modification 5) In each of the above-mentioned embodiments, the two shearing parts 20 are formed in a straight line parallel to each other (see Figs. 1 and 5). However, this is not limiting, and in a modification, the two shearing parts 20 may be formed in any shape, such as a bent line, a curved line, etc. In still another modification, the two shearing parts 20 may be formed asymmetrically.

[0068] (Variation 6) In each of the above-mentioned embodiments, the filter medium 2, 102 separates the liquid from the raw material transported in the transport direction. However, the filter medium 2, 102 may be capable of separating the liquid from the raw material even when the raw material input to the surface 6 side is not transported. For example, the filter medium 2, 102 may be a filter medium that separates the liquid from the raw material by applying pressure to the raw material input to the surface 6 side in a direction toward the surface 6 (by so-called pressure filtration). In this variation, each shearing section 20 may be formed along any direction. For example, each shearing section 20 may be formed in a random direction.

[0069] (Modification 7) Furthermore, in the filter medium 2, 102 of each of the above-mentioned embodiments, each shearing portion 20 may be formed along any direction. For example, each shearing portion 20 may be formed in a random direction.

[0070] In addition, the technical elements described in this specification or drawings exert technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving one of those objectives is itself technically useful. [Explanation of symbols]

[0071] 2: Filter medium 4: Main unit 6: Surface of the main body 8: Back of the unit 10: Processing section for deliquification 16: Surface of processed part for drainage 18: Back side of drainage processing section 20: Shear section 30: Vertical hole 70: Barrel 70a: First barrel member 70b: second barrel member 72: Inlet end 74: Outlet side end 80: Spiral 82: Rotation axis 84: Screw helical member 102: Filter medium

Claims

1. A method for producing a filter medium for separating liquid from a solid-liquid mixed raw material, comprising: A processing step of forming a plurality of drainage processing parts by pressing and punching a plurality of parts of a planar filter body having a surface on the side where the solid-liquid mixed raw material contacts and a back surface on the opposite side of the surface in a thickness direction; and a push-back step of pushing back the multiple processed parts for liquid removal by pressing the multiple processed parts for liquid removal in a direction opposite to a pressing direction in the processing step after the processing step, Each of the multiple drainage processing parts is sandwiched between two shear parts, A method for manufacturing a filter medium, wherein the two shearing portions are portions where the filter medium body is sheared between the front surface and the back surface by the press.

2. The solid-liquid mixed raw material is transported on the surface in a predetermined transport direction, The method for producing a filter medium according to claim 1 , wherein the two shearing portions are formed along the conveying direction.

3. The method for producing a filter medium according to claim 1 or 2, wherein the plurality of drainage processed portions are formed flush with the filter medium body after the push-back step.

4. In the processing step, the filter body is pressed from the front surface to the back surface to punch out the multiple locations, thereby forming the multiple drainage processed portions, A method for manufacturing a filter material described in any one of claims 1 to 3, wherein the surface of each of the numerous drainage processing portions is recessed relative to the surface of the filter material body, and the back surface of each of the numerous drainage processing portions protrudes relative to the back surface of the filter material body.

5. A method for manufacturing a filter material according to any one of claims 1 to 4, wherein in the processing step, the numerous staggered locations of the filter material body are pressed and punched out in the thickness direction to form the numerous drainage processing portions in a staggered arrangement.

6. The method for producing a filter medium according to any one of claims 1 to 5, further comprising a forming step of forming the filter medium body into a cylindrical shape after the multiple drainage processed portions are formed.

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