JP5743527B2 - Sludge scraping machine - Google Patents

Description

  The present invention relates to a sludge scraping machine that is provided in a sludge sedimentation basin such as a sewage treatment plant and scrapes sludge accumulated on the bottom of the sludge sedimentation basin.

  As such a sludge scraper, for example, as described in Patent Documents 1 and 2, a flight is attached to a chain that is arranged so as to be wound endlessly in a sludge settling basin and run around. In addition, it is known that the sludge accumulated on the bottom of the sludge sedimentation basin by this flight is scraped. In the sludge scraping machines described in these Patent Documents 1 and 2, the chain and the flight sink into the treated water in the sludge settling basin due to their own weight, and the flight shoe slides on the rail laid on the bottom of the settling pond. While scraping the sludge.

  However, in such a sludge scraper, the flight moves while the shoes slide in contact with the rails laid on the bottom of the sedimentation basin where the sludge accumulates, and there is a problem that the rails and shoes wear significantly due to the sludge. . Further, when the rail is laid on the bottom surface of the sedimentation basin in this way, it is extremely difficult to scrape the sludge accumulated around the rail.

  Therefore, for example, in Patent Documents 3 and 4, the flight is formed so as to float with the chain by buoyancy, and a presser rail is provided on the flight to prevent the flight when the flight is below the sedimentation basin. In such a sludge scraping machine, the presser rail with which the flight shoe comes into sliding contact is arranged at a distance from the bottom surface of the sedimentation basin. Wear can be suppressed, and since there is no obstacle on the bottom surface, the accumulated sludge can be scraped and discharged evenly.

JP 2000-334216 A JP 2009-244102 A Japanese Unexamined Patent Publication No. 53-55655 Japanese Patent Laid-Open No. 3-238006

  By the way, in such a sludge scraper, the chain itself and the flight may be submerged due to their own weight, or the chain itself may be lifted in the treated water, and the chain itself may be extended due to wear or the like. When the tension is weakened, there is a possibility that the chain cannot be stably run around the chain, or in some cases, the chain may be detached from the wound sprocket. For this reason, if the chain length increases, the scraper operation must be stopped to drain the treated water from the settling basin, the sprocket shaft must be moved, or the number of chain links must be reduced. In the meantime, the sludge cannot be settled in the sedimentation basin.

  In this regard, in the case where the chain and flight are submerged in the treated water under their own weight, the chain and flight are self-weighted in this part by providing a part that sag downwards in the travel path of the upper chain. Since the chain can sink and tension can be applied to the entire chain, the frequency of chain tension adjustment work can be reduced to some extent. However, if the chain and the flight are made to float in the treated water, the tension cannot be applied by such means.

  Therefore, in the case where the chain and the flight are caused to float in the treated water, a device for applying tension to the chain, such as a pressing member described in Patent Document 2, must be provided. Of course, the structure of the machine becomes complicated, and if a large tension is always applied to the chain as described in Patent Document 2, the chain is extended and the chain tension adjustment work is frequently performed. There is a risk.

  The present invention has been made under such a background, and in a sludge scraping machine in which a sludge scraping body composed of a chain and a flight floats in treated water, tension is applied to the chain such as the pressing member. An object of the present invention is to provide a sludge scraping machine capable of reducing the frequency of chain tension adjustment work without requiring a device for imparting the above.

In order to solve the above-described problems and achieve such an object, the present invention provides a chain that is disposed so as to be wound endlessly in a sludge settling basin and is run around. A flight that scrapes the sludge accumulated on the bottom is attached to form a sludge scraping body, and this sludge scraping body floats in the treated water in the sludge sedimentation basin, and the upper side in the sludge sedimentation pond The traveling path of the sludge scraping body includes an upper rail that suppresses the floating of the sludge scraping body, and the upper surface of the sludge scraping body is allowed to float in the treated water without being provided with the upper rail. A chain tension region in which the sludge scraping body does not float on the surface of the treated water is provided.

  In the sludge scraping machine having such a configuration, as described above, the upper rail and the chain tension area where the upper rail is not provided are provided in the traveling path of the upper sludge scraping body in the sludge sedimentation basin. The sludge scraper, which is composed of chains and flights and floats in the treated water in the sedimentation basin, will float in the treated water in this chain tension area and be pulled to the floating part. Tension is applied to the entire chain.

  Therefore, even if the chain is extended, it is possible to prevent the chain from being detached from the sprocket by absorbing this in the chain tension region. In addition, since such extension is absorbed between the position of the treated water surface of the sludge settling basin in the chain tension region and the height of the sludge scraping body that rises, the frequency of chain tension adjustment work can be reduced. it can.

  For this reason, it is not necessary to provide a device for applying a large tension to the chain as described above, and the tension applied to the entire chain is increased by appropriately setting the buoyancy of the sludge scraper in the chain tension region. Since it can be adjusted so that it does not become too much, it is possible to prevent a situation in which the chain is extended due to excessive tension being applied.

  Here, the end of the upper rail adjacent to the chain tension region is formed to be curved upward toward the chain tension region, so that the chain that floats in the chain tension region can be It is possible to prevent the parts from being caught and damaged.

  In addition, the chain may be configured such that a part of the upper traveling path is floated on the water surface of the treated water held in the sludge settling basin except in the chain tension region. If the chain is wound around only a pair of sprockets provided at both ends of this travel path, the number of sprockets can be minimized and the sludge scraped. The structure of the machine can be further simplified.

  In particular, when the chain is wound around a pair of sprockets so that the entire travel path is disposed in the treated water, the upper travel path and the lower side when the flight sews sludge. The traveling path of the sludge scraper can be provided close to the top and bottom. Therefore, like the scraping machines of Patent Documents 3 and 4, when a lower rail is provided on the lower travel path to suppress the sludge scraping body from floating, at least a part of the lower rail and the upper rail is provided. It can be supported by a common support member provided in the sludge settling basin, and this also simplifies the structure of the scraper and provides a low-cost and efficient sludge scraper. Become.

  As described above, according to the present invention, it is possible to always apply appropriate tension to the entire chain without requiring a device for applying tension to the chain and complicating the structure of the scraper. In addition, it is possible to minimize the delay in processing in the sludge settling basin by reducing the frequency of chain tension adjustment work.

It is a top view which shows the 1st Embodiment of this invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is CC sectional drawing in FIG. It is DD sectional drawing in FIG. It is a top view which shows the 2nd Embodiment of this invention. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG.

  1 to 5 show a first embodiment of the present invention. In this embodiment, as shown in FIG. 1 and FIGS. 3 to 5, two sludge sedimentation basins P having the same shape and the same size, which are rectangular in plan view, are arranged in parallel. In each of the ponds P, the sludge scraper of the present embodiment having the same shape and the same structure is also provided. Therefore, in FIG. 1 and FIGS. 3 to 5, only the sludge scraping machine in one sludge sedimentation basin P is provided, and the other is omitted.

  The sludge settling basin P includes a bottom surface Q having a rectangular shape as described above, a pair of long wall surfaces R that rise in a direction perpendicular to the bottom surface Q and extend in the longitudinal direction of the rectangle, and these long wall surfaces It is formed by being surrounded by a pair of short wall surfaces S that are perpendicular to R and the bottom surface Q and face in the longitudinal direction, and one short wall surface S of the bottom surfaces Q (the short wall surface on the left side in FIGS. 1 and 2). The side S) is made deeper and is a mud pit T from which the sludge scraped is discharged. In addition, the inclined surface U which inclines so that it may mutually approach as it goes to the bottom face Q side is formed in the corner part which the bottom face Q and a pair of long wall surface R cross | intersect.

  As shown in FIG. 2, the position immediately above the boundary portion between the mud pit T and the bottom surface Q, and the other short wall surface S of the pair of short wall surfaces S (the short wall surface S on the right side in FIGS. 1 and 2). At the position immediately above the bottom surface Q on the side, as shown in FIG. 3 and FIG. 5 at each position, at the tip of the sprocket support shaft 1 provided so as to be vertically projected from both long wall surfaces R, Sprockets 2A and 2B are attached so as to be rotatable around this axis. The other sprocket 2B on the other short wall surface S side is attached to the sprocket support shaft 1 and cantilevered independently of each other, whereas the one sprocket 2A on the mud pit T side is a through shaft. 3 are connected to each other and can be rotated together.

  A driving sprocket 4 is attached to one of the two sprockets 2A arranged on the side of the mud pit T so as to be integrally rotatable around the one sprocket 2A and the axis. The sprocket 4 is connected to a rotating shaft of a driving device 5 provided on the sludge sedimentation basin P via a chain or the like, and the driving sprocket 3 and the through shaft 3 are rotated by rotating the rotating shaft of the driving device 5. The two one sprockets 2A connected to each other are rotated around the axis in a predetermined direction (clockwise direction in FIG. 2). In addition, this drive sprocket 4 is between the sludge scrapers in the two sludge sedimentation basins P, as shown in FIGS. 1 and 3, and the sprocket at the tip of the sprocket support shaft 1 protruding from the long wall surface R adjacent to each other. It is attached to 2A.

  Thus, the total of four sprockets 2A and 2B arranged in one sludge settling basin P is a pair of sprockets 2A and 2B at the tip of the sprocket support shaft 1 protruding from the same long wall surface R of the pair of long wall surfaces R. The chain 6 is positioned on one vertical surface spaced from each long wall surface R, and the chain 6 is wound around the pair of sprockets 2A, 2B in an endless manner within the vertical surface. Are wound around each.

  Therefore, in this embodiment, as shown in FIG. 1 and FIGS. 3 to 5, the pair of chains 6 are positioned on both long wall surfaces R side in one sludge sedimentation basin P, and the sprocket 2 </ b> A is driven by the drive device 5. By rotating, the chain 6 is rotated in the same traveling direction F as the predetermined direction in the vertical plane between the pair of sprockets 2A and 2B while the sprocket 2B is driven to rotate. The length of the chain 6 is longer than the length when the chain is wound around the pair of sprockets 2A and 2B without slack.

  In addition, the pair of chains 6 positioned on both long wall surfaces R side in this way are flighted so as to extend between the two chains 6 perpendicularly to the vertical plane outside the ring formed by the wound chain 6. 7 is spanned and both ends thereof are attached. As shown in FIGS. 3 to 5, the flight 7 has a length in the direction perpendicular to the vertical surface longer than the distance between the pair of chains 6, and the bottom surface Q between the inclined surfaces U of the sludge settling basin P is formed. The length is slightly smaller than the width and is positioned between the inclined surfaces U. Further, as shown in FIG. 2, the flight 7 is provided with a scraping surface 7 </ b> A so as to be always perpendicular to the direction in which the chain 6 extends. The sludge scraping body 8 in the present embodiment is configured.

  Furthermore, the sludge scraping body 8 configured in this manner is caused to float in the treated water W introduced into the sludge settling basin P. In order to make the sludge scraping body 8 float in the treated water W in this way, even if the chain 6 sinks in the treated water W, the sludge is caused by the flight 7 floating in the treated water W. The scraper 8 may float in the treated water W, or vice versa, and both the flight 7 and the chain 6 may float in the treated water W.

  However, since tension is applied to the chain 6 as will be described later, the chain 6 is made of plastic such as reinforced polyester resin or polyacetal resin, so that the weight can be reduced even if it sinks in the treated water W. It is desirable that the sludge scraping body 8 as a whole floats in the treated water W, ensuring strength and flying the flight 7 in the treated water W with greater buoyancy. As described above, in order to float in the treated water W with the greater buoyancy of the flight 7, for example, the flight 7 itself is formed in a hollow shape with a light and high-strength material such as fiber reinforced resin, or the flight 7 Such a hollow float or a float made of polystyrene foam having a small specific gravity or the like may be attached to the back surface of the scraping surface 7A.

  Furthermore, shoes 7B are attached to both ends of the flight 7 that will protrude outside the pair of chains 6, and these shoes 7B are located above and below the sprockets 2A and 2B in the sludge settling basin P. Both are provided so as to extend along the longitudinal direction, and can be slidably contacted with an upper rail 9A and a lower rail 9B which are both long and flat. Here, the upper rail 9A and the lower rail 9B are for guiding the flight 7 of the sludge scraping body 8 to be floated in the treated water W as described above by pressing from the upper side. Since the portion slidably contacting the upper rail 9A and the portion slidably contacting the lower rail 9B are opposite to each other, the shoe 7B is attached to the both sides of the flight 7.

  Further, as shown in FIG. 2, the lower rail 9B extends between the lower edge portions of the pair of sprockets 2A and 2B so as to extend substantially in parallel with the bottom surface Q of the sludge settling basin P. The flight 7 in which the shoe 7B is in sliding contact with the lower rail 9B has a small edge between the bottom surface Q of the sludge settling basin P as shown in FIGS. It arrange | positions so that this space | interval may be opposed to this bottom face Q.

  Accordingly, when the chain 6 travels around the traveling path of the sludge scraping body 8 below the sprockets 2A and 2B in the sludge settling basin P, the flight 7 remains in this manner with a small space between the bottom surface Q and the flight 7 as described above. It moves parallel to the bottom surface Q along the lower rail 9B in the traveling direction F, that is, the direction from the other short wall surface S of the sludge settling basin P toward the drainage pit T, and scrapes the sludge accumulated on the bottom surface Q. At the same time, it is discharged to the mud pit T.

  On the other hand, as shown in FIG. 2, the upper rail 9A is disposed so as to extend from a position slightly above the upper edge of one sprocket 2A to the other sprocket 2B in parallel with the lower rail 9B. Yes. However, while the lower rail 9B is arranged between the pair of sprockets 2A and 2B as described above, the upper rail 9A is changed from one sprocket 2A side to the other sprocket 2B in this embodiment. As a result, a region where the upper rail 9A is not provided on the other sprocket 2B side is formed in the traveling path of the sludge scraper 8 on the upper side of the sprockets 2A and 2B in the sludge settling basin P. This region is a chain tension region X in the present embodiment.

  Therefore, in this chain tension region X, the sludge scraping body 8 that has been floated in the treated water W is allowed to float without being pressed by the upper rail 9A and bulges upward so as to bulge upward. 6 is wound around the other sprocket 2B and pulled back to the lower traveling route. In addition, the length of the chain 6 is set so that the sludge scraping body 8 that floats in the chain tension region X in this manner floats only in the treated water W held in the sludge settling basin P. In X, the flight 7 and the chain 6 do not float on the surface of the treated water W. Moreover, the end part adjacent to the chain tension | tensile_strength area | region X of 9 A of upper rails is formed so that it may curve upwards as it goes to the chain tension | tensile_strength area | region X side, as shown in FIG.

  The upper rail 9A and the lower rail 9B are supported by a common support member 10 provided in the sludge settling basin P except for the chain tension region X where the upper rail 9A is not provided. That is, in the region where the upper rail 9A extends in parallel with the lower rail 9B, the sludge is disposed at equal intervals in the longitudinal direction at the position where the upper rail 9A is disposed in the vertical direction as shown in FIG. A prismatic upper support portion 10A of the support member 10 protrudes vertically from the pair of long wall surfaces R of the settling basin P, and an upper rail 9A is attached to the lower surface of the tip portion of the upper support portion 10A. Yes.

  In addition, the lower surface of the upper support portion 10A slightly rearward than the front end portion to which the upper rail 9A is attached is provided with an L-shaped prismatic bottom that extends downward and bends in parallel with the upper support portion 10A. The side support portion 10B is attached so as not to interfere with the inclined surface U, and the lower rail 9B is attached to the lower surface of the distal end portion of the lower support portion 10B. In the chain tension region X where the upper rail 9A is not provided, the support member 10 may be disposed by removing the tip of the upper support portion 10A to which the upper rail 9A is attached.

  In the sludge scraper configured in this way, the sludge scraper 8 composed of the chain 6 and the flight 7 floats in the treated water W in the sludge settling basin P, and in the lower travel route, When the shoe 7B of the flight 7 is slidably contacted with the lower rail 9B disposed on the upper side of the flight 7, the flight 7 is moved in the traveling direction F while being pressed down, and the sludge is raked up. Drain to T. Accordingly, a space is provided between the bottom surface Q of the sludge sedimentation basin P where the sludge accumulates and the lower rail 9B, so that the shoe 7B does not slide in contact with the lower rail 9B in the accumulated sludge, It is possible to prevent the wear of the lower rail 9B and the shoe 7B from being promoted.

  Further, since the lower rail 9B is disposed above the bottom surface Q with an interval therebetween, it is possible to avoid an obstacle from being disposed on the bottom surface Q, so that the sludge accumulated on the bottom surface Q is evenly scraped by the flight 7. It can be discharged reliably. In particular, in the present embodiment, the support member 10 that supports the lower rail 9B and the upper rail 9A and the sprocket support shaft 1 that rotatably supports the sprockets 2A and 2B also protrude from the long wall surface R of the sludge settling basin P. Therefore, these do not become obstacles in the sludge scraping.

  On the other hand, in the upper traveling route in the sludge settling basin P, an area provided with an upper rail 9A that slidably contacts the shoe 7B of the flight 7 and restrains the sludge scraper 8 from floating, and the upper rail. The chain tension region X in which 9A is not provided is provided, and in this chain tension region X, the sludge scraping body 8 floats freely in the treated water W, so that tension is applied to the entire chain 6. For this reason, even if the chain 6 is extended due to wear or the like, it can be absorbed by the extension of the chain 6 in the chain tension region X, and the tension of the chain 6 can be prevented from weakening.

  Therefore, according to the sludge scraping machine having the above-described configuration, the sludge scraping body 8 floats in the chain tension region X by appropriately setting the buoyancy of the sludge scraping body 8 and the section in which the chain tension region X is provided. Therefore, it is possible to always apply an appropriate tension to the chain 6, so that the sludge scraping can be stably and efficiently performed without causing the extended chain 6 to be detached from the sprockets 2 </ b> A and 2 </ b> B. You can do it.

  In addition, since the extension of the chain 6 is absorbed at a distance between the water surface position of the treated water W in the chain tension region X and the protruding height of the sludge scraping body 8 protruding so as to bulge upward, there is a margin in this interval. By providing the above, the frequency of the chain tension adjustment work can be reduced. Furthermore, it is not necessary to separately provide a device for applying such tension to the chain 6, and it is possible to prevent the structure of the sludge scraper from becoming complicated, and to apply an excessively large tension. In other words, the life of the chain 6 is not shortened.

  In the present embodiment, the end portion of the upper rail 9A adjacent to the chain tension region X is curved upward as it goes to the chain tension region X side. The chain 6 and the flight 7 of the sludge scraping body 8 that rises in this way are not caught by the end portion and damaged, and the chain 6 and the flight 7 are smoothly lifted in the chain tension region X, thereby ensuring more reliability. In addition, the frequency of chain tension adjustment work can be reduced.

  On the other hand, in the present embodiment, the entire travel path of the sludge scraping body 8 is disposed in the treated water W held in the sludge settling basin P, and each chain 6 is disposed at both ends of the travel path. Only a pair of provided sprockets 2A and 2B are wound around and run around. That is, since the traveling path of the sludge scraping body 8 is formed by the minimum number of sprockets 2A and 2B for one chain 6, according to this embodiment, the structure of the sludge scraper is further simplified. Can be

  In addition, since the chain 6 is wound only around the pair of sprockets 2A and 2B and the entire travel path is disposed in the treated water W, the upper travel path and the lower side of the sprockets 2A and 2B are disposed. Accordingly, the distance between the upper rail 9A and the lower rail 9B other than the chain tension region X of the sludge scraper 8 that travels around these travel paths can be minimized. it can. For this reason, since the support member 10 that supports the upper rail 9A and the lower rail 9B can be made common in the portion where they extend in parallel, according to this embodiment, the sludge scraper The structure can be further simplified, and a sludge scraping machine capable of stable sludge scraping as described above can be provided at a lower cost.

  However, in the first embodiment, the chain 6 is wound only around the pair of sprockets 2A, 2B in this way, so that the entire travel path of the sludge scraping body 8 is disposed in the treated water W. Although configured, for example, as in the second embodiment of the present invention shown in FIGS. 6 to 8, the chain 6 may be wound around two or more sprockets 2 to form a traveling path, Further, the flight 7 of the sludge scraping body 8 may float on the surface of the treated water W in a portion other than the chain tension region X. In the second embodiment, the same reference numerals are assigned to portions common to the first embodiment, and description thereof is omitted. Also, since the figures corresponding to the CC cross section and DD cross section in FIG. 2 are the same as those in the first embodiment, the illustration is omitted.

  That is, in the second embodiment, the lower portion of the pair of sprockets 2A, 2B and the chain tension region X in the traveling path of the sludge scraping body 8 are the same as in the first embodiment. On the other hand, a third sprocket 2C is disposed slightly above the position of the water surface of the treated water W above the one sprocket 2A of the pair of sprockets 2A and 2B. On the other short wall surface S side, the third sprocket 2C and the fourth sprocket 2D are arranged so as to be slightly below the position of the water surface of the treated water W with a space in the longitudinal direction. Has been. The drive sprocket 4 is attached to the third sprocket 2 </ b> C and connected to the rotation shaft of the drive device 5.

  Further, in the present embodiment, the upper rail 9A has an end portion on one short wall surface S side above the fourth sprocket 2D and is located on the water surface of the treated water W, and the other short wall surface S side. That is, it descends as it goes to the chain tension region X side and is submerged in the treated water W, and is made parallel to the lower rail 9B at the substantially central portion in the longitudinal direction of the sludge settling basin P, and then the chain as in the first embodiment. As it goes to the tension region X side, it is curved upward and interrupted, so that it shifts to the chain tension region X. In this way, in the portion where the upper rail 9A and the lower rail 9B extend in parallel, the upper rail 9A and the lower rail 9B are also a common support member that protrudes from the long wall surface R of the sludge settling basin P as in the first embodiment. 10 is supported.

  Also in the sludge scraping machine of the second embodiment configured as described above, the sludge scraping body 8 including the chain 6 and the flight 7 is in the treated water W in the chain tension region X as in the first embodiment. Since tension is applied to the entire chain 6 by floating, even if the chain 6 is extended due to wear or the like, the chain 6 and the flight 7 can stably travel by absorbing this. Further, since the end portion of the upper rail 9A adjacent to the chain tension region X is curved upward, it is possible to prevent the flight 7 and the like from being caught, and at least the upper rail 9A and the lower rail 9B are parallel to each other. Since these parts can be supported by the common support member 10, the apparatus structure can be prevented from becoming complicated.

  Further, in this second embodiment, the chain 6 is also wound around the third and fourth sprockets 2C and 2D located slightly below the position of the water surface of the treated water W. In the portion between the fourth sprockets 2C and 2D, the flight 7 is positioned on the upper side of the chain 6, and the sludge scraping body 8 composed of the chain 6 and the flight 7 floats in the treated water W. Together with this, the upper part of the flight 7 can be lifted from the surface of the treated water W between the third and fourth sprockets 2C and 2D as shown in FIG.

  For this reason, according to the present embodiment, the sludge accumulated on the bottom surface Q of the sludge settling basin P can be scraped up by the flight 7 and discharged into the waste mud pit T, as well as the third and fourth sprockets. 2C and 2D, the flight 7 that has risen from the surface of the treated water W can also squeeze the scum that floats near the water surface. The scum thus squeezed is adjacent to, for example, the fourth sprocket 2D. By providing scum discharging means on the running direction F side of the chain 6, further clarification of the treated water W introduced into the sludge settling basin P can be promoted.

  In these first and second embodiments, the chain 6 is wound around the other sprocket 2B, which is the end portion on the traveling direction F side in the traveling path of the upper sludge scraper 8 in the chain tension region X. In the case where the entire travel path of the chain 6 is located in the treated water W in the sludge settling basin P as in the first embodiment, the travel direction of the upper travel path is provided. F may be provided at a portion where the chain 6 is wound around the one sprocket 2A, which is an end on the rear side, and for example, an upper rail 9A is provided above each of the pair of sprockets 2A and 2B. It is good also as the chain tension | tensile_strength area | region X, without providing the upper rail 9A in this part. Further, a plurality of chain tension regions X may be provided.

DESCRIPTION OF SYMBOLS 1 Sprocket support shaft 2A-2D Sprocket 5 Drive device 6 Chain 7 Flight 7A Scraping surface 7B Shoe 8 Sludge scraping body 9A Upper rail 9B Lower rail 10 Support member F Running direction of sludge scraping body 8 P Sludge sedimentation basin W treatment Water X Chain tension area

Claims (4)

A chain that is arranged so as to be wound endlessly in the sludge sedimentation basin and travels around is attached to a flight that scrapes the sludge accumulated on the bottom surface of the sludge sedimentation basin to constitute a sludge scraping body, The sludge scraping body floats in the treated water in the sludge sedimentation basin, and the upper rail that suppresses the sludge scraping body in the traveling path of the upper sludge scraping body in the sludge sedimentation pond. And a chain tension region that allows the sludge scraping body to float in the treated water without being provided with the upper rail, and that the sludge scraping body that has floated does not float on the surface of the treated water ; A sludge scraping machine characterized in that is provided.   2. The sludge scraper according to claim 1, wherein an end portion of the upper rail adjacent to the chain tension region is formed to be curved upward toward the chain tension region side.   The sludge scraping body is characterized in that the entire travel path is disposed in the treated water, and the chain is wound only on a pair of sprockets provided at both ends of the travel path. The sludge scraping machine according to claim 1 or claim 2.   A lower rail is also provided in the traveling path of the sludge scraping body on the lower side in the sludge sedimentation basin, and at least a part of the lower rail and the upper rail is provided. The sludge scraper according to any one of claims 1 to 3, wherein the sludge scraper is supported by a common support member provided in the sludge settling basin.

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