Sludge scraping device

Abstract

To provide a sludge scraping apparatus which is provided in a sedimentation basin in which sludge contained in water received on the upstream side is sedimented on the bottom surface of the basin, and scrapes the sludge sedimented on the bottom surface of the basin, and in which wear of a sliding contact member is suppressed.SOLUTION: A sliding contact member 722 which is provided with a locking portion side 722a and is in contact with the guide rail 2, and a scraping member 3 in which an internal space IS is formed, the scraping member 3 scraping the biosludge settled on the pond bottom surface side 9f by reciprocating between the upstream side and the downstream side on the pond bottom surface side 9f side along the guide rail 2 via the sliding contact member 722, wherein the scraping member 3 is prevented from being shifted to the downstream side by extending in the pond widthwise direction, being placed on the sliding contact member 722, and being locked to the locking portion side 722a, A synthetic resin-foamed body FS is arranged in the internal space IS, and the synthetic resin-foamed body FS is arranged on an upper space 722a above the locking part IS4 in the internal space IS.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sludge scraper that is installed in a sedimentation tank where sludge contained in received water settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank. [Background technology]

[0002] A so-called reciprocating sludge scraper is known, which is equipped with a scraper member that moves back and forth along a guide rail attached to the bottom of a sedimentation basin, and the scraper member's reciprocating movement scrapes the sludge that has settled on the bottom of the basin in stages in the forward direction. In Patent Document 1, the applicant of the present application proposed a reciprocating sludge scraper in which, in order to reduce friction with the guide rail, a sliding member is provided between the guide rail and the scraper member that slides against the guide rail as the scraper member moves back and forth. In the sludge scraper described in Patent Document 1, the guide rail is made of ultra-high molecular weight polyethylene, which increases wear resistance and makes it easy to replace the sliding member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-180247 Summary of the Invention [Problem to be solved by the invention]

[0004] The applicant of the present application constructed a sludge collection device using the technology disclosed in Patent Document 1, and while actually operating the device, learned that when collecting sludge containing a large amount of inorganic components such as sand, the inorganic components could become lodged in the guide rail and the sliding member could slide over them, causing the sliding member to wear out faster than expected.

[0005] SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a sludge scraper that is devised to suppress wear of the sliding contact members. [Means for solving the problem]

[0006] The sludge scraper of the present invention, which solves the above-mentioned object, is A sludge scraper is provided in a sedimentation tank where sludge contained in water received upstream settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank, A guide rail provided on the bottom surface of the pond; a sliding contact member provided with a locking portion and in contact with the guide rail; A scraper member having an internal space formed therein scrapes the sludge settled on the bottom surface of the pond by moving back and forth between the upstream side and the downstream side on the bottom surface of the pond along the guide rail via the sliding contact member, The guide rail extends in a direction perpendicular to the width direction of the sedimentation basin in a part of the width direction of the sedimentation basin, The scraper member extends in the pond width direction, is placed on the sliding contact member, and is engaged with the engaging portion to prevent it from shifting toward the downstream side. A synthetic resin foam is disposed in the internal space. The synthetic resin foam is disposed in an upper space of the internal space, above the engaging portion.

[0007] Also, the scraper member has a scraper surface facing the upstream side and an inclined surface inclined downward from an upper end portion of the scraper surface toward the downstream side, The internal space may be a space surrounded by the scraping surface and the inclined surface. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a sludge scraper that is devised to suppress wear of the sliding contact members. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a side cross-sectional view of a settling tank in which a sludge scraper according to one embodiment of the present invention is installed. FIG. [Figure 2] FIG. 2 is a plan view of the settling basin shown in FIG. 1, seen from above. [Figure 3] 2. FIG. 3(a) is an enlarged view of the circled portion A in FIG. 2, and FIG. 3(b) is a cross-sectional view taken along line BB in FIG. [Figure 4] 3 is a cross-sectional view taken along CC in FIG. 2. [Figure 5] 3(a) is a diagram showing a state in which the polystyrene foam has been removed from the internal space of the scraper member shown in FIG. 3(b), and FIG. 3(b) is a diagram showing a state in which the polystyrene foam has been inserted into the internal space of the scraper member shown in FIG. 3(a). [Figure 6] FIG. 10 is a perspective view schematically showing a scraper member that reciprocates along a guide rail. [Figure 7] 1 is a plan view showing the entire sludge scraping device of the present embodiment. FIG. [Figure 8] 10A and 10B are diagrams showing modified examples of the scraper member; [Figure 9] FIG. 8 is a plan view, seen from above, of a settling basin in which a sludge collector is installed, the overall configuration of which is different from that of the sludge collector described with reference to FIGS. 1, 2 and 7. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will now be described with reference to the drawings. The sludge scraper of this embodiment is a so-called reciprocating type sludge scraper equipped with scraping members that reciprocate along guide rails provided on the bottom of the settling basin.

[0011] Fig. 1 is a side cross-sectional view of a settling tank 9 in which a sludge scraper 10 according to one embodiment of the present invention is installed. Fig. 2 is a plan view of the settling tank 9 shown in Fig. 1, viewed from above. In Figs. 1 and 2, the central portion of the settling tank 9 in the longitudinal direction (the left-right direction in the drawings) is omitted.

[0012] The sedimentation basin 9 shown in Figures 1 and 2 is a pond that is roughly rectangular in plan view and is surrounded by an upstream wall 9a, a downstream wall 9c, and a pair of side walls 9d. This sedimentation basin 9 receives sewage such as wastewater and rainwater from a water conduit 9e on the left side of Figure 1, allows the sludge contained in the received sewage to settle on the pond bottom 9f, and then drains the water from the right side of Figure 1. Hereinafter, the left side in Figures 1 and 2 will be referred to as the upstream side, and the right side in Figures 1 and 2 will be referred to as the downstream side.

[0013] As shown in Figures 1 and 2, the sedimentation tank 9 is provided with a sludge collector 10 of this embodiment and a sludge pit 91. The sludge pit 91 is provided on the upstream side of the sedimentation tank 9. The direction perpendicular to the paper surface in Figure 1 and the up-and-down direction in Figure 2 are referred to as the tank width direction. The bottom surface 9f of the sedimentation tank 9 is a slightly inclined surface so that the water depth of the sedimentation tank 9 increases toward the upstream side. The sludge collected in the sludge pit 91 is discharged outside the sedimentation tank 9 by a sludge pump (not shown).

[0014] The sludge collection device 10 of this embodiment comprises a guide rail 2 fixed to the pond bottom surface 9f, a plurality of collection members 3, a connecting rod 4 (see Figure 2) that connects the plurality of collection members 3, a drive rod 5 that moves the collection members 3 back and forth, a drive mechanism 6 that imparts a driving force to the drive rod 5, and a fixing mechanism 7 that fixes the collection members 3 to the drive rod 5 and the connecting rod 4.

[0015] 1, the drive mechanism 6 includes a motor 61, a converter 62 that converts the rotational drive force of the motor 61 into reciprocating motion, a reciprocating rod 63 having one end fixed to the output shaft of the converter 62, a triangular link 64 attached to the lower end of the reciprocating rod 63, a link support 65 that rotatably supports the triangular link 64, and a connecting pipe 66 that connects the triangular link 64 and the drive rod 5. Note that in FIG. 2, members that make up the drive mechanism 6 other than the connecting pipe 66 are not shown.

[0016] As shown in FIG. 1 , the motor 61 is disposed on the ground. The unidirectional rotational drive force of the motor 61 is converted by a converter 62 into a drive force that moves the reciprocating rod 63 up and down. When the reciprocating rod 63 moves up and down, the triangular link 64 swings in the direction of arrow P. When the triangular link 64 swings, the drive rod 5, which is connected to the triangular link 64 by a connecting pipe 66, moves back and forth between the upstream and downstream sides along the guide rail 2 fixed to the pond bottom 9 f. That is, when the reciprocating rod 63 is driven downward, the triangular link 64 swings toward the upstream side, and the drive rod 5 advances toward the upstream side. Conversely, when the reciprocating rod 63 is driven upward, the triangular link 64 swings toward the downstream side, and the drive rod 5 retreats toward the downstream side. Multiple water collector members 3 are fixed to the drive rod 5. When the drive rod 5 moves back and forth, each water collector member 3 moves back and forth between the upstream and downstream sides along the guide rail 2. Hereinafter, the direction in which the scraper member 3 reciprocates will be referred to as the reciprocating direction, and this reciprocating direction is the longitudinal direction of the settling basin 9.

[0017] The collection members 3 are arranged at equal or approximately equal intervals in the direction of their reciprocating movement. Each collection member 3 extends in the width direction of the settling basin 9. The stroke of the reciprocating movement of the collection members 3 is set to a distance equal to or greater than the distance between the collection members 3 in the direction of reciprocating movement. The sludge that has settled in the settling basin 9 is gradually collected by the reciprocating movement of the collection members 3 toward the sludge pit 91, one stroke at a time, and sent to the sludge pit 91.

[0018] The guide rails 2 are made of, for example, ultra-high molecular weight polyethylene and extend in the longitudinal direction of the sedimentation tank 9 as shown in FIG. 2 . In other words, the guide rails 2 extend perpendicular to the width of the tank at a portion of the width of the tank. In this embodiment, a total of three guide rails 2, one at the center of the width of the tank and one at each end of the width of the tank, are fixed to the bottom surface 9f of the sedimentation tank 9. The drive rod 5 is located in the center of the width of the tank and extends in the direction of reciprocation of the collector members 3. One connecting rod 4 is located at each end of the width of the tank. The drive rod 5 and the connecting rod 4 are hollow rectangular prisms made of stainless steel, each 100 mm on a side and 2 mm thick, and both ends are closed. Therefore, both the drive rod 5 and the connecting rod 4 have internal gas reservoirs. Each connecting rod 4 extends the entire length of the reciprocation direction of the collector members 3, and each of the collector members 3 is fixed by a fixing mechanism 7. As a result, each connecting rod 4 connects all of the multiple sludge collector members 3. Because each collector member 3 is connected by the connecting rod 4 at both end portions in the pond width direction, each collector member 3 is integrated at both sides in the pond width direction, increasing the rigidity of the collector members 3 as a whole. This prevents the both end portions in the pond width direction of each collector member 3 from bending in the direction of reciprocating movement, or each collector member 3 from tilting relative to the pond width direction. If the collector members 3 bend or tilt, there is a risk that sludge will be left behind at the ends in the pond width direction. The drive rod 5 is an example of a connecting member, and the connecting rod 4 is also an example of a connecting member.

[0019] Furthermore, the drive rod 5 and the connecting rod 4 are connected by multiple connecting bars 41, 42. These multiple connecting bars consist of two first connecting bars 41, 41 and two second connecting bars 42, 42. The two first connecting bars 41, 41 extend in the pond width direction and connect the drive rod 5 and the connecting rod 4, respectively. The two second connecting bars 42, 42 are inclined toward the drive rod 5 as they move downstream from the connecting rods 4 located at both ends in the pond width direction. These multiple connecting bars 41, 42 are arranged in a triangular shape as shown in Figure 2, thereby integrating the drive rod 5 and the two connecting rods 4 with high rigidity. Furthermore, two second connecting bars 42, 42 are fixed to the drive rod 5 near the location where the connecting pipe 66 is attached. The triangularly arranged connecting bars 41, 42 efficiently transmit the driving force transmitted from the drive mechanism 6 to the driving rod 5 to the connecting rod 4, and as the driving rod 5 moves back and forth, the two connecting rods 4 also move back and forth. In other words, the two connecting rods 4 also have the function of moving the scraper member 3 back and forth. The triangularly arranged connecting bars 41, 42 are located above the scraper member 3 and are an example of a transmission member that transmits the driving force to the connecting rods 4 at both ends. Hereinafter, the triangularly arranged connecting bars 41, 42 will be collectively referred to as triangular transmission member 40.

[0020] In addition, two additional first connecting bars 41, 41 are provided upstream of the triangular transmission member 40, in addition to the two first connecting bars 41, 41 that constitute the triangular transmission member 40, and connect the drive rod 5 and the connecting rod 4. Hereinafter, these additional first connecting bars 41, 41 are referred to as downstream connecting members 41L. Furthermore, downstream meandering suppression rollers 81 with vertically extending rotation axes are attached near each end of the downstream connecting member 41L in the pond width direction. The downstream meandering suppression rollers 81 are located further outward in the pond width direction than the guide rails 2 installed at both ends of the pond width direction. When the reciprocating fixing mechanism 7 collides with the downstream meandering suppression rollers 81, suppressing the meandering of the scraper member 3. When the reciprocating fixing mechanism 7 collides with the downstream meandering suppression roller 81, the downstream meandering suppression roller 81 rotates, reducing the force of the collision.

[0021] Two first connecting bars 41, 41 are also provided at the upstream end near the sludge pit 91, and connect the drive rod 5 and connecting rod 4. Hereinafter, the first connecting bars 41, 41 at the upstream end will be referred to as the upstream connecting member 41U. Furthermore, upstream meandering suppression rollers 82 similar to the downstream meandering suppression roller 81 are attached near each end of the upstream connecting member 41U in the pond width direction, thereby suppressing meandering of the scraper member 3.

[0022] Fig. 3(a) is an enlarged view of the circled portion A in Fig. 2, and Fig. 3(b) is a cross-sectional view taken along line BB in Fig. 2. Fig. 4 is a cross-sectional view taken along line CC in Fig. 2.

[0023] As shown in Figure 3(b), the collecting member 3 has a collecting surface 31 facing upstream and collecting sludge settled on the pond bottom surface 9f toward the upstream side (the sludge pit 91 side shown in Figures 1 and 2), an inclined surface 32 inclined downward from the upper end portion 31a of the collecting surface 31 toward the downstream side, an upstream-side turn-back portion 33 that turns back from the lower end portion 31b of the collecting surface 31 toward the downstream side, and a downstream-side turn-back portion 34 that turns back from the lower end portion of the inclined surface 32 toward the upstream side, forming an internal space IS. Polystyrene foam FS having closed cells is placed in a portion of the internal space IS shown in Figure 3(b). A detailed description of the internal space IS and the polystyrene foam FS will be provided later.

[0024] In addition, the boundary portion of the collecting member 3 between the collecting surface 31 and the inclined surface 32 is the apex 3a, and the boundary portion between the inclined surface 32 and the downstream turned-back portion 34 is the downstream end portion 3b.

[0025] The collection surface 31 is formed in an arc shape with its upper end portion 31a and lower end portion 31b projecting upstream and its central portion recessed downstream. When the collection member 3 moves upstream, the collection surface 31 collects the sludge upstream. Meanwhile, the inclined surface 32 is inclined toward the pond bottom surface 9f so that the collection member 3 tapers downstream. When the collection member 3 moves downstream, the sludge climbs over the inclined surface 32, allowing the majority of the sludge to remain at the position collected by the collection surface 31. The collection member 3 is made of a bent stainless steel plate.

[0026] 3 and 4, the fixing mechanism 7 that fixes the scraper member 3 to the drive rod 5 has a pair of angles 71, 71, a mounting member 72, and a pressing member 73. The fixing mechanism 7 that fixes the scraper member 3 to the connecting rod 4 has the same configuration as the fixing mechanism 7 that fixes the scraper member 3 to the drive rod 5, so a description thereof will be omitted. Note that FIG. 4 shows a gas reservoir AT formed inside the drive rod 5.

[0027] Each of the pair of angles 71 is an L-shaped metal fitting made of stainless steel, and is welded to each of both sides of the drive rod 5 in the width direction in an attitude extending in the vertical direction. The angles 71 are formed with an insertion hole 71a through which a bolt 731 (described later) is inserted.

[0028] As shown in FIG. 3(b), the mounting member 72 has a fixed wall 721 extending from the upstream portion of the mounting member 72; a sliding portion 722 extending downstream from the lower end of the fixed wall 721 and placed on the guide rail 2; and a receiving portion 723 projecting diagonally upward toward the upstream side from the downstream end of the sliding portion 722. The mounting member 72 of this embodiment is a so-called stainless steel casting. The sliding portion 722 made of stainless steel has lower wear resistance than the guide rail 2 made of ultra-high molecular weight polyethylene. This is intended to reduce wear on the guide rail 2, which requires time-consuming replacement. As shown in FIG. 4, the fixed wall 721 of the mounting member 72 extends across the pair of angle brackets 71 in the pond width direction. As shown in FIG. 3, an insertion hole 721a is formed at a position corresponding to the insertion hole 71a of the angle bracket 71.

[0029] As shown in FIG. 3( a), the sliding contact portion 722 is a generally rectangular portion in a plan view, and its length in the reciprocating direction is longer than that of the scraper member 3. In this embodiment, the length of the sliding contact portion 722 in the pond width direction is slightly longer than that of the drive rod 5 in the pond width direction. As shown in FIG. 3( b), the sliding contact portion 722 is the portion on which the scraper member 3 is placed. Specifically, the upstream turn portion 33 and the downstream turn portion 34 of the scraper member 3 are placed on the upper surface of the sliding contact portion 722. The lower surface of the sliding contact portion 722 comes into sliding contact with the guide rail 2 when the scraper member 3 reciprocates, thereby reducing wear between the scraper member 3 and the guide rail 2. This sliding contact portion 722 is an example of a sliding contact member. Therefore, there is no need to provide a separate member, such as a shoe, to reduce friction with the guide rail. Additionally, the sliding contact portion 722 is formed with a second receiving portion 722a that protrudes upward, and this second receiving portion 722a is the portion that engages with the upstream folded portion 33 of the scraper member 3 placed on the sliding contact portion 722. When sludge is scraped upstream, pressure is applied to the scraper surface 31 from the upstream side toward the downstream side, and the upstream folded portion 33 is pushed toward the downstream side. The second receiving portion 722a receives, from the downstream side, the upstream folded portion 33 that is pushed toward the downstream side. This second receiving portion 722a prevents the position of the scraper surface 31 from shifting downstream, and enables the scraper member 3 to be stably fixed.

[0030] The receiving portion 723 is provided in an inclined position corresponding to the scraping surface 31 so that the downstream portion including the downstream end portion 3b of the scraping member 3 can be inserted between the receiving portion 723 and the sliding contact portion 722. The receiving portion 723 is provided with a reinforcing rib 723a.

[0031] As shown in FIGS. 3(a) and 4, the pressing members 73 are provided on both sides of the drive rod 5 in the width direction. Also, as shown in FIG. 3(a), each pressing member 73 has a bolt 731, three nuts 732, a cap 733, and a washer 734. In this embodiment, the bolt 731, the nuts 732, and the washer 734 are made of stainless steel, and the cap 733 is made of synthetic resin. The cap 733 has a disk-shaped abutment portion 733a.

[0032] As shown in FIGS. 3(a) and 3(b), a bolt 731, with a nut 732 and a washer 734 attached, is inserted from the upstream side to the downstream side through the insertion hole 71a of the angle 71 and the insertion hole 721a of the fixed wall 721. Two nuts 732 are attached to the bolt 731 inserted through the insertion holes 71a and 721a on the downstream side of the fixed wall 721. These two nuts 732 form a so-called double-nut structure that functions to prevent the bolt 731 from loosening. The mounting member 72 is fixed to the angle 71 by these nuts 732 and the bolt 731. A cap 733 is attached to the downstream end of the bolt 731 inserted through the insertion holes 71a and 721a. A contact portion 733a of the cap 733 contacts the scraping surface 31, pressing the scraping surface 31 from the upstream side to the downstream side. The pressing member 73 of this embodiment presses the central portion of the collecting surface 31 in the height direction, i.e., the portion between the upper end portion 31a and the lower end portion 31b of the collecting surface 31. Here, the pressing member 73 may press either the upper end portion 31a or the lower end portion 31b of the collecting surface 31, or may press both the upper end portion 31a and the lower end portion 31b of the collecting surface 31.

[0033] The accumulator member 3, pressed by the pressing member 73 toward the downstream side, is received from the downstream side by the receiving portion 723 of the mounting member 72. Specifically, the downstream portion of the accumulator member 3 abuts against the receiving portion 723, preventing the accumulator member 3 from moving downstream. In other words, the accumulator member 3 is fixed to the mounting member 72 by being pressed downstream by the pressing member 73 in a state where its downstream movement is prevented by the receiving portion 723. In this way, the accumulator member 3 is fixed to the drive rod 5 by the fixing mechanism 7.

[0034] In the fixing mechanism 7 described above, by loosening the nut 732 and moving the bolt 731 upstream, the pressing force pressing against the collection surface 31 is released, and the collection member 3 can be removed from the mounting member 72. Therefore, compared to conventional sludge collection devices in which the collection member is fixed to the drive rod or the like by welding or the like, the work of replacing the collection member 3 can be carried out more easily.

[0035] FIG. 5(a) is a diagram showing a state in which the polystyrene foam has been removed from the internal space of the scraper member shown in FIG. 3(b).

[0036] An opening 3H is provided on the underside 3U of the scraper member 3. That is, the upstream turn-back portion 33 and the downstream turn-back portion 34 are spaced apart, and the space between them (see the arrow in FIG. 5(a)) forms the opening 3H. The opening 3H is provided continuously in the pond width direction, but as shown in FIG. 3(b), the portion located above the guide rail 2 is blocked by the sliding portion 722 of the fixing mechanism 7. Therefore, of the opening 3H extending in the pond width direction, an opening 3H1 (see FIG. 6) is provided in a portion where the guide rail 2 is not present. The upstream edge that defines the opening 3H is referred to as the upstream edge 331, and the downstream edge that defines the opening 3H is referred to as the downstream edge 341.

[0037] 5(a) also shows the region of the internal space IS. Specifically, the lower space IS1 connected to the opening 3H, the upstream lower corner space IS2 upstream of the lower space IS1, the downstream lower corner space IS3 downstream of the lower space IS1, and the upper space IS4 above the lower space IS1 are shown, each separated by a two-dot chain line. The upstream lower corner space IS2 is the space directly above the upstream turn-back portion 33, and the downstream lower corner space IS3 is the space directly above the downstream turn-back portion 34.

[0038] FIG. 5(b) is a diagram showing a state in which polystyrene foam is inserted into the internal space of the scraper member shown in FIG. 5(a).

[0039] Styrofoam FS has closed cells and tends to float on water. In other words, it is a substance with a specific gravity of 1 or less. Instead of Styrofoam FS, synthetic resin foams such as polyurethane foam, polyethylene foam, and polypropylene foam may be used. Alternatively, solid polyethylene or polypropylene, which also has a specific gravity of 1 or less, may be used.

[0040] The polystyrene foam FS is inserted into the internal space IS from one longitudinal end of the scraper 3. In the scraper 3 shown in Fig. 5(b), the upper space IS4 described using Fig. 5(a) is filled with polystyrene foam FS, and the spaces below the upper space IS4 within the internal space IS (the lower space IS1, the upstream lower corner space IS2, and the downstream lower corner space IS3) are empty.

[0041] Fig. 6 is a perspective view showing a scraper member 3 that moves back and forth along the guide rail 2. The scraper member 3 moves back and forth along the guide rail 2 via the sliding contact portion 722 of the fixing mechanism 7, but the fixing mechanism 7 is not shown in Fig. 6.

[0042] FIG. 6 shows one guide rail 2. This guide rail 2 is the guide rail installed in the center of the pond width direction as shown in FIG. 2. FIG. 6 also shows two scraper members 3, but only the center portions of each of these two scraper members 3 in the pond width direction are shown. The cross sections of each of the two scraper members 3 are shown diagonally to the front left of the figure. In all of the scraper members 3 provided in the sludge scraper device 10, openings 3H1 open toward the pond bottom surface 9f between the guide rail 2 installed in the center of the pond width direction as shown in FIG. 6 and guide rails (not shown) installed at both ends of the pond width direction, and in the portions of the sludge scraper members 3 outside the guide rails installed at both ends of the pond width direction.

[0043] In FIG. 6, the upstream scraper 3 moves upstream as indicated by the straight arrow f, scraping up sludge with the scraper surface 31. If the downstream lower corner space IS3 is empty, the sludge accumulated on the pond bottom surface 9f is scraped up by the downstream edge 341. If the lower space IS1 is empty, the sludge scraped up by the downstream edge 341 enters the lower space IS1, stirring up the sludge that has settled on the pond bottom surface 9f. Furthermore, in this embodiment, the upstream lower corner space IS2 is also empty, so the sludge is stirred using the wide lower space, including the downstream lower corner space IS3, the lower space IS1, and the upstream lower corner space IS2. This prevents the sludge accumulated on the pond bottom surface 9f from remaining there for a long time and causing the sludge to decay.

[0044] Meanwhile, the downstream scraper 3 moves downstream as indicated by the straight arrow b, and the sludge climbs over the inclined surface 32. If the upstream lower corner space IS2 is empty, the sludge accumulated on the pond bottom 9f is scraped up by the upstream edge 331. If the lower space IS1 is empty, the sludge scraped up by the upstream edge 331 enters the lower space IS1, stirring up the sludge that has settled on the pond bottom 9f. Furthermore, in this embodiment, the downstream lower corner space IS3 is also empty, so the sludge is stirred even when using a wide range of lower spaces, including the upstream lower corner space IS2, the lower space IS1, and the downstream lower corner space IS3. As a result, even when the scraper 3 moves downstream, the sludge accumulated on the pond bottom 9f does not remain there for a long time, preventing the sludge from decaying.

[0045] Next, the resultant force of the sludge scraper 10 will be described.

[0046] Figure 7 is a plan view showing the entire sludge collector device of this embodiment. Although finer details are less visible in Figure 7 than in Figure 2, unlike Figure 2, the longitudinal center portion is shown without omission, and therefore all of the collector members 3 included in the sludge collector device 10 of this embodiment are visible. The sludge collector device 10 of this embodiment is equipped with a total of 78 collector members 3, and in Figure 7, the collector members 3 are numbered in order, starting from the collector member 3 at the upstream end.

[0047] The sludge collector 10 of this embodiment is divided into three regions. The first region A1 includes the area where the triangular transmission member 40 located on the downstream end is located, and extends from the midpoint between the 70th and 71st collector members 3 to the downstream ends of the drive rod 5 and the connecting rods 4, 4. Therefore, the 71st to 78th collector members 3 are located in this first region A1. The second region A2 includes the area where the connecting members 41U and 41L are located, and is divided into two regions, an upstream region and a downstream region. Specifically, the upstream region includes the area where the upstream connecting member 41U is located, and extends from the midpoint between the second and third collector members 3 to the midpoint between the seventh and eighth collector members 3. The downstream region includes the region where the downstream connecting member 41L is disposed, and extends from the midpoint between the 65th and 66th collector members 3 to the midpoint between the 70th and 71st collector members 3. Therefore, the third to seventh collector members 3 and the 66th to 70th collector members 3 are disposed in this second region A2. The third region A3 is the region from the upstream to downstream ends of the drive rod 5 and the connecting rods 4, 4, excluding the first and second regions. Therefore, the first and second collector members 3 and the eighth to 65th collector members 3 are disposed in this third region A3.

[0048] The resultant force is calculated by subtracting the buoyant force from the gravity acting on an object. If this resultant force is positive, the object will sink in water, and if it is negative, the object will float. The resultant force (N) here is the product of the object's volume (m3), the acceleration of gravity, and the object's density minus the density of water (kg / m3). In what follows, gravity acting on an object will be shown as weight.

[0049] The weight of the entire first area A1 includes the weight of the triangular transmission member 40, the weight of the eight scraper members 3, the weight of the portion of the drive rod 5 that is included in the first area A1, and the weight of each of the two connecting rods 4, 4 that is included in the first area A1. If no polystyrene foam FS is placed in the internal space IS of the eight scraper members 3, and the drive rod 5 is a stainless steel hollow rectangular prism with a side length of 40 mm and a thickness of 4 mm, and the connecting rod 4 is a stainless steel hollow rectangular prism with a side length of 40 mm and a thickness of 2 mm, the resultant force per meter in the first area A1 will be 459 N / m. On the other hand, in the first area A1 of the sludge collector 10 of this embodiment, the resultant force per meter (first resultant force) is 78.5 N / m, which means that the surface pressure on the sliding contact parts 722 in the first area A1 is only about 1 / 6 of that in the case of 459 N / m, and wear on the sliding contact parts 722 is also reduced to about 1 / 6. Each of the eight collector members 3 included in the first area has expanded polystyrene FS arranged over the entire length of the collector member 3.

[0050] The weight of the entire second region A2 includes the weight of the upstream connecting member 41U, the weight of the two upstream meandering suppression rollers 82, 82, the weight of the downstream connecting member 41L, the weight of the two downstream meandering suppression rollers 81, 81, the weight of all ten scraper members 3, the weight of the portion of the drive rod 5 that is included in the second region A2, and the weight of the portion of each of the two connecting rods 4 that is included in the second region A2. If no polystyrene foam FS is placed in the internal space IS of the ten scraper members 3, the drive rod 5 is a stainless steel hollow rectangular prism with a side length of 40 mm and a thickness of 4 mm, and the connecting rod 4 is a stainless steel hollow rectangular prism with a side length of 40 mm and a thickness of 2 mm, the resultant force per meter in the second region A2 is 363 N / m. On the other hand, in the second area A2 of the sludge collector 10 of this embodiment, the resultant force per meter (second resultant force) is 15.7 N / m, which significantly reduces the surface pressure on the sliding contact parts 722 in the second area A2 and significantly reduces wear on the sliding contact parts 722. Each of the ten collector members 3 included in the second area has expanded polystyrene FS arranged over 80% of the total length of the collector members 3, and the value of the second resultant force is adjusted so that it does not become too small.

[0051] The total weight of the third area A3 is the weight of the 60 sludge collector members 3, the weight of the portion of the drive rod 5 that is included in the third area A3, and the weight of the portion of each of the two connecting rods 4, 4 that is included in the third area A3. If the polystyrene foam FS is not placed in the internal space IS of the 60 collector members 3, the drive rods 5 are stainless steel hollow rectangular prisms with sides of 40 mm and a thickness of 4 mm, and the connecting rods 4 are stainless steel hollow rectangular prisms with sides of 40 mm and a thickness of 2 mm, the resultant force per meter in the third area A3 is 332 N / m. On the other hand, the resultant force per meter in the third area A3 of the sludge collector 10 of this embodiment (third resultant force) is 14.7 N / m, which significantly reduces the surface pressure on the sliding contact portion 722 in the third area A3 and significantly reduces wear on the sliding contact portion 722. Each of the ten scraper members 3 included in the third region has expanded polystyrene FS arranged over 65% of the total length of the scraper member 3, and the value of the third resultant force is adjusted so that it does not become too small.

[0052] As described above, the sludge collector 10 of this embodiment reduces the surface pressure between the guide rail 2 and the sliding contact portion 722, thereby suppressing wear on the sliding contact portion 722. Furthermore, the members that move in the longitudinal direction of the settling basin 9 (the drive rod 5, the two connecting rods 4, 4, and the collector member 3) are lighter, so less driving force is required, leading to a reduction in the driving force of the sludge collector 10.

[0053] The resultant force per meter is preferably 200 N / m or less and 10.7 N / m or more, and more preferably 100 N / m or less and 11.7 N / m or more. If this resultant force is too large, the surface pressure on the sliding contact portion 722 of the fixing mechanism 7 becomes too great, causing wear of the sliding contact portion 722 to progress at an unacceptable rate. On the other hand, if this resultant force is a negative value, the scraper member 3 will float, and if it is a positive value but too small, the scraping force of the scraper member 3 will decrease and it will no longer be able to scrape heavy sludge. After extensive research, the inventors have found a suitable range of resultant force that can suppress wear of the sliding contact portion 722 while ensuring the scraping force of the scraper member 3.

[0054] Of the first, second and third resultant forces, the first resultant force is the largest, but if these three resultant forces are set to the same value or similar values, the amount of wear of the sliding contact portion 722 in each of the regions A1 to A3 will also be approximately the same, and the replacement times for the mounting members 72 can be uniformed.

[0055] The sludge scraper of the present embodiment described above has the following features: A sludge scraper is provided in a sedimentation tank where sludge contained in received water settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank, A guide rail provided on the bottom surface of the pond; a sliding contact member in contact with the guide rail; a scraper member that scrapes up sludge that has settled on the bottom surface of the pond by reciprocating along the guide rail via the sliding contact member, A buoyant force is applied to the member that is driven in the extending direction of the guide rail.

[0056] More specifically, a drive mechanism that generates a drive force for reciprocating the scraper member; a connecting member extending in the same direction as the extending direction and connecting the plurality of scraping members at intervals in the reciprocating movement direction; a transmission member located above some of the plurality of scraper members and transmitting the driving force to the connecting member, The member that is driven in the extending direction is given buoyancy.

[0057] The member that is driven in the extending direction may be the scraping member, the connecting member, or the transmission member.

[0058] To provide buoyancy may mean providing a buoyancy imparting member (for example, a member with a specific gravity of 1 or less) or a buoyancy imparting structure (for example, a structure that forms a gas reservoir).

[0059] The sedimentation basin may have buoyancy imparting members extending in the width direction of the sedimentation basin, or may have buoyancy imparting members extending in the reciprocating movement direction. The sedimentation basin may have buoyancy imparting members extending across the entire width or almost the entire width of the sedimentation basin, or may have buoyancy imparting members extending across the entire length or almost the entire length of the sedimentation basin. Alternatively, the sedimentation basin may have buoyancy imparting structures extending across the width direction of the sedimentation basin, or may have buoyancy imparting structures extending in the reciprocating movement direction. The sedimentation basin may have buoyancy imparting structures extending across the entire width or almost the entire width of the sedimentation basin, or may have buoyancy imparting structures extending across the entire length or almost the entire length of the sedimentation basin.

[0060] The guide rails are provided in a plurality in the width direction of the pond, The scraper members are provided in a plurality in the extension direction, and each extends in the pond width direction across a plurality of the guide rails, The connecting members are provided at a plurality of locations in the pond width direction, a connecting member extending in the pond width direction and connected to connecting members provided at a plurality of locations in the pond width direction; Among a first resultant force obtained by subtracting the buoyancy of the entire first region from the weight of the entire first region including the arrangement region of the transmitting member, a second resultant force obtained by subtracting the buoyancy of the entire second region from the weight of the entire second region including the arrangement region of the connecting member, and a third resultant force obtained by subtracting the buoyancy of the entire third region from the weight of the entire third region, which is the region from one end to the other end of the connecting member excluding the first region and the second region, the first resultant force may be the largest. Also, the second resultant force may be the second largest. In other words, the third resultant force may be the smallest.

[0061] Figure 8 shows modified examples of the scraper member. Figures 8(a) to 8(d) are all views showing the cross section of the scraper member. Note that components with the same names as those explained so far will be described using the same reference numerals as those used so far.

[0062] The sludge scraper 3 shown in FIG. 8(a) has a larger cross-sectional area of ​​the polystyrene foam FS than the sludge scraper 3 shown in FIG. 5(b). That is, both the upstream lower corner space IS2 and the downstream lower corner space IS3 are filled with polystyrene foam, and further, the upstream end and downstream end, which are part of the lower space IS1, are filled with polystyrene foam. As a result, the sludge scraper 3 shown in FIG. 8(a) can reduce the resultant force compared to the sludge scraper 3 shown in FIG. 5(b). In the sludge scraper 3 shown in FIG. 8(a), because the downstream lower corner space IS3 is filled with polystyrene foam, it is difficult for the downstream edge 341 to scrape up the sludge that has settled to the pond bottom surface 9f. Because the upstream lower corner space IS2 is also filled with polystyrene foam, it is also difficult for the upstream edge 331 to scrape up the sludge that has settled to the pond bottom surface 9f. However, a notch FS1 is provided in the bottom surface of the polystyrene foam FS shown in FIG. 8(a). This cutout FS1 has a downstream rising wall FS11 that rises upstream of the downstream edge 341 and an upstream rising wall FS12 that rises downstream of the upstream edge 331. When the scraper 3 shown in FIG. 8(a) moves upstream and scrapes sludge on the scraper surface 31, the sludge deposited on the pond bottom 9f is also pushed by the downstream rising wall FS11 and agitated within the cutout FS1. Similarly, when the scraper 3 shown in FIG. 8(a) moves downstream and the sludge climbs over the inclined surface 32, the sludge deposited on the pond bottom 9f is also pushed by the upstream rising wall FS12 and agitated within the cutout FS1. Therefore, the scraper 3 of the modified example shown in FIG. 8(a) can also prevent the sludge deposited on the pond bottom 9f from remaining there for a long time and causing the sludge to decay.

[0063] The cross-sectional area of ​​the polystyrene foam FS in the collector 3 shown in FIG. 8(b) is also larger than that in the collector 3 shown in FIG. 5(b). That is, in the collector 3 shown in FIG. 8(b), both the upstream lower corner space IS2 and the downstream lower corner space IS3 are filled with polystyrene foam, and further, the upper portion, which is part of the lower space IS1, is also filled with polystyrene foam. As a result, the collector 3 shown in FIG. 8(b) can also reduce the resultant force compared to the collector 3 shown in FIG. 5(b). A notch FS2 is also provided in the bottom surface of the polystyrene foam FS shown in FIG. 8(b). This notch FS2 has a downstream rising wall FS21 rising from the downstream edge 341 and an upstream rising wall FS22 rising from the upstream edge 331. When the scraper 3 shown in FIG. 8(b) moves upstream and scrapes sludge on the scraper surface 31, the sludge that has accumulated on the pond bottom 9f is also pushed by the downstream rising wall FS21 and agitated within the notch FS2. Similarly, when the scraper 3 shown in FIG. 8(b) moves downstream and the sludge climbs over the inclined surface 32, the sludge that has accumulated on the pond bottom 9f is also pushed by the upstream rising wall FS22 and agitated within the notch FS2. Therefore, the modified scraper 3 shown in FIG. 8(b) can also prevent the sludge that has accumulated on the pond bottom 9f from remaining there for a long period of time and causing the sludge to decay.

[0064] The scraper member 3 shown in FIG. 8(c) has the entire internal space IS filled with expanded polystyrene FS, and can reduce the resultant force compared to the scraper members 3 shown in FIGS. 8(a) and 8(b).

[0065] As explained above with reference to FIG. 8 , the resultant force can be adjusted by changing the cross-sectional area of ​​the polystyrene foam FS. However, the resultant force can also be adjusted by changing the length of the polystyrene foam FS, as in the regions A1 to A3 of this embodiment. For example, the polystyrene foam FS may have a length substantially the same as the length (length in the pond width direction) of the collector member 3, as in the case of the collector member 3 in the first region A1, or it may be shorter than the collector member 3, as in the case of the collector member 3 in the second region A2 and the collector member 3 in the third region A3. Here, the length of the polystyrene foam FS may be shorter than the length of the collector member 3 but longer than the length between the connecting rods 4 at one end and the other end in the pond width direction as shown in FIG. 2 , or it may be the length between the connecting rods 4, or it may be shorter than the length between the connecting rods 4 but equal to or greater than one-third of the length of the collector member 3. If the length of the polystyrene foam FS is shorter than the length of the scraping member 3, it is preferable to align the center of the polystyrene foam FS in the longitudinal direction with the center position of the scraping member 3 in the longitudinal direction.

[0066] The adjustment of the resultant force by the volume of the polystyrene foam FS has been described above, but the resultant force can also be adjusted by the expansion ratio of the polystyrene foam FS.

[0067] The scraper member 3 shown in Fig. 8(d) does not have an opening 3H on the lower surface 3U, and the internal space IS is a sealed space without polystyrene foam FS. The internal space IS shown in Fig. 8(d) functions as a gas reservoir, and air is sealed in this internal space IS. Note that a gas with a specific gravity less than that of air (e.g., helium gas) may also be sealed in.

[0068] 4 can also be used to adjust the resultant force. In this embodiment, both the gas reservoir AT of the drive rod 5 and the gas reservoir of the connecting rod 4 are sealed with air, but the resultant force can be reduced by sealing in a gas with a lower specific gravity than air (e.g., helium gas). Furthermore, by reducing the cross-sectional area of ​​the pipe-shaped drive rod 5 or connecting rod 4 with closed ends, the resultant force can be reduced, and by increasing the cross-sectional area, the resultant force can be increased.

[0069] Furthermore, even if other longitudinal members such as the first connecting bar 41 and the second connecting bar 42 (triangular transmission member 40 and / or connecting members 41U, 41L) are made pipe-shaped with both ends closed, the resultant force can be reduced by the gas reservoir.

[0070] In addition, a floating member extending in the longitudinal direction of the settling basin 9 may be provided. For example, a floating member having a specific gravity of 1 or less and the same length as the drive rod 5 may be fixed to the drive rod 5, or a floating member having a specific gravity of 1 or less and the same length as the connecting rod 4 may be fixed to the connecting rod 4. Alternatively, a floating member extending in the width direction of the settling basin 9 may be provided. The floating member may be a plastic tubular member with both ends sealed, or may be a synthetic resin foam, etc.

[0071] Figure 9 is a plan view, seen from above, of a settling basin equipped with a sludge collector, the overall configuration of which is different from that of the sludge collector explained using Figures 1, 2 and 7. Note that components with the same names as those explained so far will be explained using the same reference numerals as those used so far.

[0072] As with Figure 2, Figure 9 also omits the central portion of the sedimentation tank 9 in the longitudinal direction (left-right direction in the figure). The sedimentation tank 9 shown in Figure 9 also receives sewage from the left side of the figure, settles the sludge contained in the received sewage to the tank bottom surface 9f, and discharges it from the right side of the figure. In Figure 9, the left side of the figure is the upstream side and the right side is the downstream side. Also, in Figure 9, the collector members 3 are numbered in order from the downstream end collector member 3.

[0073] In the sludge collector 10 shown in Figure 9, a connecting pipe 66 is connected to the upstream portion of the drive rod 5, and a triangular transmission member 40 is also provided on the upstream side. Although not shown in Figure 9, the members constituting the drive mechanism 6 other than the connecting pipe 66 are also located on the upstream side. The collection surface 31 of each collection member 3 faces upstream, and in the sludge collector 10 shown in Figure 9, sludge is also collected toward a sludge pit 91 provided on the upstream side.

[0074] In the sludge collector 10 shown in Figure 9, the resultant force in the first area A1 (first resultant force) is also greater than the resultant forces in the other areas A2 and A3 (second resultant force and third resultant force). In the sludge collector 10 shown in Figure 9, heavy sludge tends to settle upstream, so the first resultant force on the upstream side is greater, which has the advantage of making it easier to collect heavy sludge. In other words, in a settling basin 9 where heavy sludge may settle, it may be preferable to make the resultant force greater on the upstream side than on the downstream side.

[0075] As explained using Figure 9, the present invention is not particularly limited to the type of drive mechanism that reciprocates the scraper member, and can be widely applied to so-called reciprocating sludge scraper devices.

[0076] According to the above description, "A sludge scraper is provided in a sedimentation tank where sludge contained in received water settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank. A guide rail provided on the bottom surface of the pond; a sliding contact member in contact with the guide rail; a scraper member having an internal space formed therein, which scrapes the sludge settled on the bottom surface of the pond by reciprocating along the guide rail via the sliding contact member; The sludge collector is characterized in that the scraper member has a substance with a specific gravity of 1 or less in the internal space. He explained about:

[0077] According to this sludge scraper, buoyancy is imparted to the scraper members, which reduces the surface pressure acting on the sliding contact members and suppresses wear on the sliding contact members.

[0078] The substance may be air, polyethylene, or polypropylene.

[0079] Also, "A sludge collector characterized in that the collector member has a synthetic resin foam disposed in the internal space." He also explained.

[0080] The synthetic resin foam may be polystyrene foam.

[0081] Also, "A sludge scraper characterized in that the synthetic resin foam has closed cells." He also explained.

[0082] Also, The guide rail extends in a direction perpendicular to the width direction of the sedimentation basin in a part of the width direction of the sedimentation basin, The scraper member extends in the pond width direction, and has an opening on its underside that communicates with the internal space in an area where the guide rail is not present in the pond width direction, The sludge scraper is characterized in that, in the region, the synthetic resin foam is disposed in the space of the internal space excluding a part or all of the lower space that communicates with the opening. He also explained.

[0083] The sludge that has settled on the bottom of the pond enters the lower space where the synthetic resin foam is not disposed through the opening, and the sludge that has settled on the bottom of the pond is stirred up. As a result, the sludge is prevented from remaining for a long time between the lower surface of the scraper member and the bottom of the pond in the area, and from decaying.

[0084] The synthetic resin foam may be filled in the internal space and have a notch cut upward in the bottom surface. This notch secures part or all of the lower space. The synthetic resin foam may be filled in the internal space excluding the area near the opening. Furthermore, the synthetic resin foam does not have to fill the entire internal space excluding part or all of the lower space that communicates with the opening.

[0085] Also, "The scraper members are provided in plural in the direction of reciprocating movement of the scraper members, a connecting member extending in the reciprocating movement direction and connecting the plurality of scraping members at intervals in the reciprocating movement direction; The sludge scraper is characterized in that the connecting member is a hollow pipe member with both ends closed. He also explained.

[0086] This provides buoyancy to the connecting member as well.

[0087] In addition, when the device includes a drive unit that generates a drive force for reciprocating the scraper members and a transmission member that is positioned above some of the multiple scraper members and transmits the drive force to the connecting member, the transmission member may also be a hollow pipe member with both ends closed. In this way, buoyancy is imparted to the transmission member as well.

[0088] According to the above description, "A sludge scraper is provided in a sedimentation tank where sludge contained in received water settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank. A guide rail provided on the bottom surface of the pond; a sliding contact member in contact with the guide rail; A scraper member having an internal space formed therein, which scrapes the sludge settled on the bottom surface of the pond by moving back and forth along the guide rail on the bottom surface side of the pond via the sliding contact member, The sludge collector is characterized in that the collector member has a synthetic resin foam disposed in the internal space. He also explained.

[0089] Also, "A sludge scraper is provided in a sedimentation tank where sludge contained in water received upstream settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank. A guide rail provided on the bottom surface of the pond; a sliding contact member in contact with the guide rail; A scraper member having an internal space formed therein scrapes the sludge settled on the bottom surface of the pond by moving back and forth between the upstream side and the downstream side on the bottom surface of the pond along the guide rail via the sliding contact member, The scraping member has a synthetic resin foam disposed in the internal space, A sludge collector characterized in that the resultant force obtained by subtracting the buoyancy of the constituent members, including the scraper member, from the weight of the constituent members is greater on the upstream side than on the downstream side. He also explained.

[0090] Also, "The scraper members are provided in plural in the direction of reciprocating movement of the scraper members, a connecting member extending in the reciprocating movement direction, to which the plurality of scraping members are connected below at intervals in the reciprocating movement direction; The sludge scraper is characterized in that the connecting member is a hollow pipe member with both ends closed and provided with a gas reservoir. He also explained.

[0091] Furthermore, the present invention is not limited to the above-described embodiment and various modifications can be made within the scope of the claims. For example, in this embodiment, the mounting member 72 having the sliding contact portion 722 is made of stainless steel casting. However, it may be made of synthetic resin for weight reduction. Alternatively, it may be made of ultra-high molecular weight polyethylene for improved wear resistance. Note that, in descending order of wear resistance against inorganic substances such as sand contained in sludge, the following materials are used: ultra-high molecular weight polyethylene, nylon, tetrafluoroethylene, carbon steel, stainless steel, high-density polyethylene, polypropylene, polyacetal, and phenolic laminate. Furthermore, in this embodiment, two connecting rods 4 are provided, but any number of connecting rods 4 may be used. Furthermore, although the sliding contact portion 722 corresponding to the shoe member is provided for each scraper member 3, it may also extend in the longitudinal direction of the sedimentation tank 9, similar to the guide rail 2. In other words, the sliding contact portions 722 of the scraper members 3 may be connected to one another.

[0092] Furthermore, even if a constituent element is included only in the description of the embodiment or modified example described above, that constituent element may be applied to other embodiments or other modified examples. [Explanation of symbols]

[0093] 10 Sludge scraper 2 guide rails 3. Scraper material 31 Raking surface 32 Slope 3H1 opening IS interior space IS1 lower space FS Styrofoam 4 connecting rods 40 Triangular transmission member 41 First connecting bar 41U Upstream connecting member 41L Downstream connecting member 42 Second connecting bar 5 Drive Rod 6 Drive mechanism 7 Fixing mechanism 72 Mounting member 722 Sliding contact part 81 Downstream meandering prevention roller 82 Upstream meandering prevention roller 9 Sedimentation tank 9f Pond bottom surface

Claims

1. A sludge scraper is provided in a sedimentation tank where sludge contained in water received upstream settles on the bottom of the tank, and scrapes up the sludge that has settled on the bottom of the tank, A guide rail provided on the bottom surface of the pond; a sliding contact member provided with a locking portion and in contact with the guide rail; A scraper member having an internal space formed therein scrapes the sludge settled on the bottom surface of the pond by moving back and forth between the upstream side and the downstream side on the bottom surface of the pond along the guide rail via the sliding contact member, The guide rail extends in a direction perpendicular to the width direction of the sedimentation basin in a part of the width direction of the sedimentation basin, The scraper member extends in the pond width direction, is placed on the sliding contact member, and is engaged with the engaging portion to prevent it from shifting toward the downstream side. A synthetic resin foam is disposed in the internal space. The sludge scraper is characterized in that the synthetic resin foam is disposed in an upper space of the internal space that is above the engaging portion.

2. the scraper member has a scraper surface facing the upstream side and an inclined surface inclined downward from an upper end portion of the scraper surface toward the downstream side, 2. The sludge scraper according to claim 1, wherein the internal space is a space surrounded by the scraping surface and the inclined surface.

Images