JP2017202477A - Sludge scraping-up machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge scraping-up machine capable of restraining an increase in weight of a chain, while restraining floating-up of the chain to a sprocket.SOLUTION: A sludge scraping-up machine comprises a plurality of sprockets, a chain 30 wound on the plurality of sprockets, a flight 50 installed in a chain and an abutting part 60 for abutting on the chain so that floating-up from the sprockets can be restrained when the chain floats up from the sprockets, and the chain rotatably connects mutual links 32 via a pin 37, and the respective links have respectively a pair of link plates 31, and an installation part 43 for installing the flight is provided in a partial specific link 44 among a plurality of links, and the installation part is provided on the one side link plate among the pair of link plates in the specific link, and the abutting part is extendedly provided so as to be positioned just above the other side link plate opposed to the one side link plate.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sludge scraper used, for example, for sewage treatment.

  2. Description of the Related Art Conventionally, as a sludge scraping machine that scrapes sludge that settles into a sedimentation basin into which sewage flows, for example, the one described in Patent Document 1 is known. The sludge scraper includes a plurality of sprockets and an endless chain wound around the sprockets. The chain includes a plurality of link plates and a plurality of attachment plates connected in series. Of these, the attachment plate has a plate-like flight in a state perpendicular to the advancing / retreating direction of the chain. Protrusions are provided for mounting. In this sludge scraper, the chain wound around the sprocket is moved around the sprocket so that the flight attached to the protrusion of the attachment plate is on the outer periphery of the chain orbit. The flight attached to the chain scrapes the sludge that has settled in the sedimentation basin.

  In addition, in such a sludge scraper, when an impact is applied from the outside due to an earthquake or the like, for example, the chain may be lifted from the sprocket, and the chain may jump out of the sprocket or fall off the sprocket. That is, during an earthquake, a so-called sloshing phenomenon occurs in which the surface of the sewage in the settling pond rises or falls more than usual. In that case, the endless chain wound around the plurality of sprockets in the settling basin is lifted by the sewage whose surface is greatly raised by the sloshing phenomenon, and the chain is lifted from the sprocket.

  Therefore, in Patent Document 2, a guide pin is provided extending in the axial direction from one end of a connecting pin that connects the link plates in the chain in series, and the guide pin extends along the sprocket circumferential direction on the outer peripheral side of the sprocket. It is made to slide on the inner peripheral surface of the arcuate plate-shaped guide member provided on the surface. That is, when the chain is about to lift from the sprocket, the guide member is brought into contact with the guide pin extended from the connecting pin of the chain from the outside in the radial direction of the sprocket, thereby suppressing the lifting of the chain. A sludge scraper is described.

JP 2003-236309 A JP 2011-78903 A

  By the way, in the sludge scraping machine of patent document 2, the end of the connection pin which is one of the components of a chain is extended further in an axial direction, and the guide pin is provided. Therefore, the length of the connecting pin that connects the link plates in the chain in series is longer than the connecting pin in the normal chain by the amount that the portion that becomes the guide pin is extended in the axial direction, and includes many such connecting pins. The weight of the entire chain will increase.

  This invention is made in view of such a situation, The objective is to provide the sludge scraping machine which can suppress the increase in the weight of a chain, suppressing the lift of the chain with respect to a sprocket. .

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The sludge scraper that solves the above problems is a plurality of sprockets, an endless chain wound around the plurality of sprockets, and attached to the chain, and the chain moves around as the sprocket rotates. A flight that moves on the outer circumference side of the circular orbit of the chain and scrapes sludge, and a contact portion that abuts against the chain so as to suppress the lifting from the sprocket when the chain is lifted from the sprocket; The chain includes a plurality of links arranged in series, wherein the links adjacent to each other in the series direction are rotatably connected via pins, and each link crosses the series direction in the width direction of the chain. Each having a pair of link plates facing each other, and at least some of the plurality of links The fixed link is provided with an attachment portion to which the flight is attached, and the attachment portion is connected to the chain from one link plate located on one side in the width direction of the pair of link plates in the specific link. The abutting portion is provided so as to extend outward of the orbit, and the abutting portion is a link on the other side facing the link plate on the one side in the width direction in a state where the chain is wound around the sprocket. It is provided so as to be located immediately above the plate.

  According to this configuration, even when the chain is likely to lift from the sprocket at the time of an earthquake, for example, the contact portion is in contact with the link plate, which is a general-purpose configuration in the chain, and the lift of the chain from the sprocket is suppressed. That is, of the pair of link plates, with respect to the link plate on the other side facing in the width direction with the link plate on one side provided so that the flight mounting portion extends outward of the circular orbit of the chain, The abutting portion abuts on the chain so as to suppress the lifting of the chain from the sprocket. Therefore, even if a new configuration for suppressing lifting is not added to the general-purpose configuration of the chain (for example, connecting pins, link plates, etc.), the lifting of the chain can be suppressed and the increase in the weight of the chain is suppressed. , It is possible to suppress the tooth skipping of the chain with respect to the sprocket and the dropping of the chain from the sprocket.

  In the sludge scraper, the attachment portion may have an attachment surface extending from the one side link plate toward the other side link plate in the width direction, and the flight may be attached to the attachment surface. preferable.

  According to this configuration, for example, the mounting portion has a mounting surface extending from the link plate on one side to the outer side in the width direction opposite to the link plate on the other side in the width direction of the chain. Thus, the occupied space in the circumferential movement direction of the chain provided with such an attachment portion can be narrowed.

In the sludge scraper, it is preferable that the contact portion is provided along a part of the outer peripheral edge of the sprocket.
According to this configuration, even when the chain is likely to be lifted from a sprocket around which the chain is wound in a plurality of radial outward directions of the sprocket, the abutment portion of the sprocket is in contact with such a chain. By abutting from the outside in the radial direction, it is possible to stably suppress the lifting of the chain.

  In the sludge scraper, the chain includes an inner link having a pair of inner link plates opposed in the width direction and a pair of outer links opposed in the width direction at a wider interval than the pair of inner link plates. Preferably, outer links having plates are alternately connected, and the abutting portion abuts on the inner link plate and the outer link plate when the chain is lifted from the sprocket.

  According to this configuration, the abutment portion has a relatively larger abutment portion than a configuration in which, for example, the abutting portion abuts only on the outer link plate of the inner link plate and the outer link plate to prevent the chain from dropping. Since it abuts on the chain at the abutment portion, it is possible to suppress the lifting of the chain more stably.

In the sludge scraper, it is preferable that the specific links are arranged at equal intervals in the length direction of the chain.
According to this configuration, since the flights can be evenly arranged in the length direction of the chain, the sludge can be evenly scraped.

  ADVANTAGE OF THE INVENTION According to this invention, the increase in the weight of a chain can be suppressed, suppressing the lift of the chain with respect to a sprocket.

The perspective view which shows roughly one Embodiment of a sludge scraping machine. The side view of the chain wound around the drive sprocket. The top view of the chain partially broken. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. The side view of the chain in a modification.

Hereinafter, an embodiment of a sludge scraping machine used in sewage treatment will be described with reference to the drawings.
As shown in FIG. 1, the sludge scraper 11 is disposed in a sedimentation basin 12 having a substantially rectangular parallelepiped shape. A sludge pit 14 that is recessed below the bottom surface 13 of the settling basin 12 is provided on one end side (right side in FIG. 1) in the longitudinal direction of the settling basin 12. The sludge pit 14 is provided so as to extend in the short direction intersecting with the longitudinal direction of the sedimentation basin 12 and is provided for accumulating sludge contained in the sewage stored in the sedimentation basin 12. That is, the sludge scraper 11 scrapes the sludge from the sedimentation basin 12 toward the sludge pit 14.

  The sludge scraper 11 includes a plurality of sprockets 20 and an endless chain 30 wound around the plurality of sprockets 20. Each sprocket 20 is arranged in the settling basin 12 so as to form a pair in the short direction of the settling basin 12. Of these sprockets 20, a pair of sprockets 20 on one end side (the right side in FIG. 1) where the sludge pits 14 are provided in the longitudinal direction of the settling basin 12 and disposed above the sprocket 20 are driven by a motor (not shown). A driving sprocket 21 to which a driving force is applied is provided. The pair of drive sprockets 21 are supported so as to be integrally rotatable by shafts 16 installed between the inner side surfaces 15 on both sides in the short direction of the sedimentation basin 12.

  Moreover, the upper part of the sedimentation basin 12 and a position slightly opposite to the side where the drive sprocket 21 is located from the central position in the longitudinal direction, and the lower part of the sedimentation basin 12 and both ends in the longitudinal direction. The driven sprocket 22, which is a kind of sprocket 20, is disposed in such a position as to form a pair in the short direction of the sedimentation basin 12. Each driven sprocket 22 is rotatably provided via a shaft 17 installed between the inner side surfaces 15 of the sedimentation basin 12. A chain 30 is wound around one driving sprocket 21 and three driven sprockets 22 arranged along the inner surface 15 of the settling basin 12. That is, two chains 30 are provided in the settling basin 12 so as to face each other in the short direction of the settling basin 12. Then, the driven sprocket 22 is driven to rotate with respect to the driving rotation of the driving sprocket 21 through the chain 30.

  A plurality of plate-like flights 50 extending along the short direction of the settling basin 12 are provided in the two chains 30 so as to bridge between the chains 30. These flights 50 are arranged at equal intervals along the length direction of the chain 30. Then, the two chains 30 on which the flights 50 are bridged rotate in synchronization with each other as the driving sprocket 21 and the driven sprocket 22 rotate. Then, as the chain 30 moves, the flight 50 moves around in the sedimentation basin 12 so that the sludge in the sedimentation basin 12 is scraped. In the sludge scraper 11 according to the present embodiment, the chain 30 moves in a counterclockwise direction as indicated by a white arrow in FIG. That is, when the flight 50 attached to the chain 30 moves along the bottom surface 13 of the settling basin 12, it moves from the other end side in the longitudinal direction toward one end side (left side to right side in FIG. 1). The sludge that has settled on the bottom surface 13 of the pond 12 is scraped toward the sludge pit 14.

  As shown in FIGS. 2 and 3, the chain 30 wound around the sprocket 20 is a so-called roller chain, and a plurality of links 32 each having a pair of link plates 31 facing each other are connected in series. Has been. That is, the serial direction in which the links 32 are connected is the same as the length direction of the chain 30. The pair of link plates 31 constituting the link 32 as a general-purpose configuration of the chain 30 are arranged in parallel with an interval in the width direction intersecting with the series direction.

  The plurality of links 32 include an inner link 33 having a pair of inner link plates 35 (link plates 31) facing each other in the width direction of the chain 30, and a width direction of the chain 30 at a wider interval than the pair of inner link plates 35. And an outer link 34 having a pair of outer link plates 36 (link plates 31) opposed to each other. The pair of outer link plates 36 are arranged so as to sandwich the pair of inner link plates 35 from the outside in the width direction. In short, in the inner link 33, the distance between the pair of link plates 31 (inner link plates 35) facing each other in the width direction of the chain 30 is greater than the distance between the link plates 31 (outer link plates 36) constituting the outer link 34. The link 32 is also provided to be narrow. The inner links 33 and the outer links 34 are arranged in series so as to alternate, and the end portions of the adjacent links 32 are rotatably connected via the pins 37, so that the endless chain 30 is formed. It is configured.

  As shown in FIG. 3, a cylindrical bush 38 is provided between the end portions of the inner link plates 35 constituting the inner link 33 so as to keep a space between the inner link plates 35. Yes. The bush 38 is inserted and assembled into an insertion hole 39 opened at the end of the inner link plate 35. In addition, an insertion hole 40 that is slightly smaller than the insertion hole 39 that opens in the inner link plate 35 is provided at the end of the outer link plate 36, and the pin 37 is inserted into the bush 38 through the insertion hole 40. By doing so, the inner link 33 and the outer link 34 are connected. The head portion, which is the base end portion of the pin 37, has a diameter larger than that of the insertion hole 40, and thus does not penetrate the outer link plate 36. On the other hand, in order to prevent the pin 37 from falling off the link 32, the tip of the pin 37 that penetrates the tip 37 in a direction intersecting with the extending direction of the pin 37 passes through the tip of the pin 37 that is opposite to the head portion. A fastening pin 41 is provided. Further, between the end portions of the inner link plate 35, a roller 42 that is rotatable about the bush 38 as an axis is provided. The teeth 23 of the drive sprocket 21 enter between the pair of link plates 31 and mesh with the chain 30, and the teeth 23 pass through the rollers 42 as the drive sprocket 21 rotates (counterclockwise in FIG. 2). By pushing out the chain 30, the chain 30 moves around in the settling basin 12.

  As shown in FIGS. 2, 3, and 4, an attachment portion 43 for attaching the flight 50 is provided in some of the links 32 constituting the chain 30. In the present embodiment, the link 32 provided with the attachment portion 43 is referred to as a specific link 44. In the present embodiment, the specific link 44 is configured by a part of the outer links 34 among the plurality of links 32 configuring the chain 30. Further, the pair of link plates 31 of the outer link 34 constituting the specific link 44 is configured by a pair of outer link plates 36 a and 36 b different from the pair of outer link plates 36 of the other outer links 34. The attachment portion 43 is provided on one outer link plate 36 a located on the side facing the vertical inner surface 15 of the settling basin 12 among the pair of outer link plates 36 a and 36 b in the specific link 44. That is, the attachment portion 43 is provided only on one outer link plate 36a located on one side of the pair of outer link plates 36a, 36b. The outer link plate 36a on one side where the mounting portion 43 is provided is slightly larger than the outer link plate 36b on the other side where the mounting portion 43 is not provided. The plurality of specific links 44 are arranged such that the specific links 44 are equally spaced in the length direction of the chain 30.

  The attachment portion 43 is a plate-like portion that is integrated with the outer link plate 36a on one side, and has a substantially trapezoidal shape that extends along the side surface of the outer link plate 36a so as to go outward of the circular orbit of the chain 30 that moves around. , And a rectangular flat plate portion 46 that is bent from the base portion 45 and extends along the width direction of the chain 30. The flat plate portion 46 extends in the width direction of the chain 30 from the outer link plate 36a side on one side toward the outer link plate 36b side on the other side, and the tip thereof is located above the outer link plate 36b on the other side. It is provided to cross. The flat plate portion 46 is provided with three holes 47 that are used when the flight 50 is attached. On the other hand, three holes 51 corresponding to the holes 47 of the flat plate portion 46 are formed through the flight 50, and nuts 53 are inserted at the tips of bolts 52 inserted through the holes 51 and the holes 47 of the flat plate portion 46. As a result, the flight 50 is attached to the attachment portion 43. That is, in the present embodiment, one surface of the flat plate portion 46 facing the flight 50 is an attachment surface 48 to which the flight 50 is attached.

  Further, the sludge scraper 11 includes a contact portion 60 that comes into contact with the chain 30 from the outside in the radial direction of the drive sprocket 21 when the chain 30 is lifted from the drive sprocket 21. As shown in FIG. 2, the contact portion 60 is disposed on the outer peripheral side of the circular orbit of the chain 30 and on the outer side in the radial direction of the drive sprocket 21, and extends along a part of the outer peripheral edge thereof. It has an arcuate plate shape. In other words, the contact portion 60 is provided so as to cover a part of the chain 30 wound around the drive sprocket 21 from the outer side of the orbit. The abutting portion 60 is bent so as to extend along the width direction of the chain 30 from the upper end edge having an arc shape in the plate-like member 61 supported along the side surface of the drive sprocket 21 via a bracket (not shown). It is the formed plate-shaped part.

  As shown in FIG. 4, the abutment portion 60 is formed in the width direction of the chain 30 on one side where the attachment portion 43 is provided as viewed from the outer link plate 36 b on the other side where the attachment portion 43 is not provided. From the side opposite to the outer link plate 36a, the tip end portion extends over the other side of the outer link plate 36b to an intermediate position between the two outer link plates 36a, 36b. That is, the contact portion 60 is provided so as to be positioned directly above the outer link plate 36b on the other side where the attachment portion 43 is not provided, of the pair of outer link plates 36a and 36b constituting the specific link 44. Yes. Although not illustrated, the contact portion 60 is not limited to the position on the outer side in the radial direction of the drive sprocket 21, but is on the outer peripheral side of the circular orbit of the chain 30 and on the outer side in the radial direction of the driven sprocket 22. The location is also provided.

Next, the operation of the sludge scraper 11 configured as described above will be described, particularly focusing on the effect of suppressing the lifting of the chain 30 from the sprocket 20 during an earthquake.
Now, at the time of an earthquake, a so-called sloshing phenomenon occurs, and the surface of sewage stored in the sedimentation basin 12 containing sludge greatly moves up and down due to relatively long-period vibration caused by the earthquake. Then, in the sludge scraper 11 in which the chain 30 is wound around the plurality of sprockets 20 in the settling basin 12, the chain 30 is lifted by the sewage whose surface has been greatly raised by the sloshing phenomenon, and the chain 30 is moved from the sprocket 20 to the chain 30. It seems to rise. In this case, when the chain 30 is greatly lifted toward the outer side in the radial direction of the sprocket 20, the chain 30 jumps out of the sprocket 20 or falls off the sprocket.

  In this regard, in the present embodiment, when the chain 30 is lifted from the drive sprocket 21 among the plurality of sprockets 20, for example, the contact portion 60 disposed on the radially outer side of the drive sprocket 21 is in contact with the chain 30. It abuts from above so as to suppress the lifting from 21. Specifically, when the chain 30 is lifted, the abutment portion 60 is brought into contact with the inner link 33 and the outer link 34 constituting the chain 30 from above before the chain 30 is disengaged from the teeth 23 of the drive sprocket 21. Abut. That is, the abutment portion 60 abuts against the link plate 31 of the plurality of links 32 (33, 34) constituting the chain 30 from the outer side of the circular orbit of the chain 30, so that the lifting of the chain 30 is suppressed. Therefore, tooth skipping of the chain 30 with respect to the drive sprocket 21 and dropping of the chain 30 from the drive sprocket 21 are suppressed.

  In this case, it is the link plate 31 itself, which is a general-purpose configuration of the chain 30, that the abutment portion 60 abuts from above in order to prevent the chain 30 from being lifted. It is not a new component added to the chain 30. Therefore, the weight of the chain 30 does not increase due to the addition of such new components.

  Further, the outer peripheral edge of the drive sprocket 21 is also likely to be lifted in a plurality of radially outward directions of the drive sprocket 21 such as when the chain 30 is lifted not only vertically upward but obliquely upward. The arcuate plate-shaped abutting portion 60 extending along the line can also support the lifting of the chain 30 in the plurality of directions. At that time, the abutting portion 60 is in a state of abutting on the chain 30 with many abutting portions for each link 32 including the inner link 33 and the outer link 34 connected in series.

  Further, the flat plate portion 46 which the attachment portion 43 of the flight 50 in the chain 30 extends along the width direction of the chain 30 is precipitated from the outer link plate 36a on one side facing the inner side surface 15 of the settling basin 12. Bending toward the direction away from the inner surface 15 of the pond 12. Therefore, unlike the case where the flat plate portion 46 is bent in the direction from the outer link plate 36a on one side facing the inner surface 15 of the settling basin 12 toward the inner surface 15 of the settling basin 12, the sludge scraper. 11 can also be arranged so that the chain 30 moves around the position close to the inner surface 15 of the settling basin 12.

According to said embodiment, the following effects can be acquired.
(1) For example, even when the chain 30 is likely to be lifted from the sprocket 20 at the time of an earthquake, the abutment portion 60 abuts against the link plate 31, which is a general-purpose configuration in the chain 30, so as to suppress the lift from the sprocket 20. Further, the tooth jump of the chain 30 with respect to the sprocket 20 and the drop-off from the sprocket 20 can be suppressed.

  (2) It is the link plate 31, which is a general-purpose configuration of the chain 30, that the abutment portion 60 abuts on the chain 30 so as to suppress lifting of the chain 30 from the sprocket 20. Therefore, it is possible to suppress the lifting of the chain 30 without adding a new configuration for suppressing the lifting to a general-purpose configuration (for example, a connecting pin or a link plate) in the chain 30. Therefore, it is possible to suppress tooth jumping of the chain 30 with respect to the sprocket 20 and dropping off from the sprocket 20 while suppressing an increase in the weight of the chain 30.

  (3) The mounting surface 48 of the mounting portion 43 is provided so as to extend from the link plate (outer link plate 36a) 31 on one side toward the link plate (outer link plate 36b) 31 on the other side. Since the dimension in the width direction can be reduced, the occupied space in the circumferential movement direction of the chain 30 can be narrowed.

  (4) Since the abutment portion 60 is provided along a part of the outer peripheral edge of the sprocket 20, even when the chain 30 is likely to float in a plurality of radially outward directions of the sprocket 20, When the abutment portion 60 abuts against the chain 30 from the outside in the radial direction of the sprocket 20, the lifting of the chain 30 can be more stably suppressed.

  (5) When the chain 30 is lifted from the sprocket 20, the contact portion 60 contacts the inner link 33 and the outer link 34. The contact portion 60 can be brought into contact with the chain 30, and the lifting of the chain 30 can be stably suppressed.

  (6) Since the specific links 44 are evenly arranged in the chain 30, the flights 50 can be evenly arranged in the length direction of the chain 30, so that sludge is scraped when the chain 30 moves around the circumference. It can be performed uniformly.

(7) Of the pair of outer link plates 36a and 36b, the attachment portion 43 is provided only on one outer link plate 36a, so that the weight of the chain 30 can be reduced.
In addition, you may change said embodiment as follows.

  As shown in FIG. 5, the contact portion 60 is not provided along a part of the outer peripheral edge of the sprocket 20, but, for example, the outer periphery of the circular orbit of the chain 30 between the drive sprocket 21 and the driven sprocket 22. The structure provided in the position used as the side may be sufficient. In this case, what is necessary is just to arrange | position so that it may be located in the link plate 31 of the other side in which the attaching part 43 in the chain 30 which advances / retreats along a horizontal direction is not provided.

  In the embodiment described above, the specific links 44 may not be evenly arranged in the chain 30. That is, the flights 50 may be arranged at unequal intervals in the length direction of the chain 30.

  In the above embodiment, the specific link 44 may be configured by a part of the plurality of inner links 33. Further, the specific link 44 may be configured by all the links 32 in the chain 30.

In the above embodiment, the contact portion 60 is not limited to the plate-like portion, and may be configured by a plurality of pins or the like arranged along the circular orbit of the chain 30.
In the above embodiment, the attachment portion 43 may be configured to extend from the outer link plate 36a on one side toward the inner side surface 15 of the settling basin 12.

  In the above embodiment, the attachment portion 43 may be provided on the outer link plate 36b on the other side opposite to the outer link plate 36a on the one side facing the inner surface 15 of the sedimentation basin 12.

  In the above embodiment, the link 32 included in the chain 30 may be configured to serve as the inner link 33 and the outer link 34 by, for example, inclining a pair of link plates 31 constituting the link 32.

  In the above embodiment, the contact portion 60 may not be provided along all the outer peripheral edges of the drive sprocket 21 and the driven sprocket 22. If any one of them is provided, the effect of suppressing the drop-off of the chain 30 is exhibited.

  In the above embodiment, the attachment portion 43 may be integrally assembled with a member configured separately from the outer link plate 36a.

  DESCRIPTION OF SYMBOLS 11 ... Sludge scraper, 12 ... Sedimentation basin, 20 ... Sprocket, 30 ... Chain, 31 ... Link plate, 32 ... Link, 33 ... Inner link, 34 ... Outer link, 35 ... Inner link plate, 36, 36a, 36b ... outer link plate (link plate on one side, link plate on the other side), 37 ... pin, 43 ... mounting portion, 44 ... specific link, 48 ... mounting surface, 50 ... flight, 60 ... contact portion.

Claims (5)

Multiple sprockets,
An endless chain wound around the plurality of sprockets;
A flight attached to the chain and moving the outer periphery side of the circular orbit of the chain and scraping sludge when the chain rotates around with the rotation of the sprocket;
An abutting portion that abuts against the chain so as to suppress the lifting from the sprocket when the chain is lifted from the sprocket;
In the chain, the links adjacent to each other in the series direction among a plurality of links arranged in series are rotatably connected via pins, and the links face each other in the width direction of the chain intersecting the series direction. Each has a pair of link plates,
At least some of the plurality of links are provided with an attachment portion to which the flight is attached,
The mounting portion is provided so as to extend from the one side link plate located on one side in the width direction among the pair of link plates in the specific link toward the outside of the circular orbit of the chain,
The contact portion is provided so as to be positioned immediately above the link plate on the other side facing the one side link plate in the width direction when the chain is wound around the sprocket. Machine.   2. The sludge scraper according to claim 1, wherein the attachment portion has an attachment surface extending from the one side link plate toward the other side link plate in the width direction, and the flight is attached to the attachment surface. Machine.   The sludge scraper according to claim 1 or 2, wherein the contact portion is provided along a part of an outer peripheral edge of the sprocket. The chain includes an inner link having a pair of inner link plates opposed in the width direction and an outer link having a pair of outer link plates opposed in the width direction at a wider interval than the pair of inner link plates. Concatenated to,
The sludge scraper according to any one of claims 1 to 3, wherein the contact portion contacts the inner link plate and the outer link plate when the chain is lifted from the sprocket.   The sludge scraper according to any one of claims 1 to 4, wherein the specific links are arranged at equal intervals in the length direction of the chain.

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