JP5842283B2 - Sludge scraping device - Google Patents

Description

  The present invention relates to a sludge scraping device that is provided in a sedimentation basin having a structure whose lower end portion is located below the water surface and scrapes the sludge settled on the bottom of the pond by a flight plate extending in the pond width direction.

  2. Description of the Related Art Conventionally, there is a sedimentation basin including a structure such as a trough whose lower end portion is located below the water surface and a sludge scraping device that scrapes sludge settled on the bottom of the pond. As this sludge scraping device, one that scrapes sludge at the bottom of a pond by circulating an endless chain attached with a plurality of flight plates extending in the pond width direction along a predetermined track is known. The endless chain circulates along a predetermined track by being partially wound around a rotating wheel such as a sprocket.

  By the way, an endless chain may elongate due to an endless chain conformity, a creep phenomenon, or the like. In addition, when the endless chain is made of resin, the endless chain may stretch due to water absorption in addition to the familiarity and creep phenomenon of the endless chain. When the endless chain is extended, the tension of the endless chain is lowered. When the tension is lowered, there is a problem that the endless chain is easily detached from the rotating wheel.

  Patent Document 1 includes a swing arm, a rotatable idler roller attached to the swing arm, a weight for bringing the outer peripheral surface of the roller into contact with the endless chain, and applying tension to the endless chain. A technique is disclosed in which a tension maintaining mechanism is provided in a sludge scraping device to maintain tension even when an endless chain extends.

JP 2009-244102 A

  However, the technique proposed in Patent Document 1 is a configuration in which tension is maintained by adding a large number of components such as a swing arm, a roller, and a weight to a sludge scraping device. For this reason, there is a problem that the number of parts of the sludge scraping device is greatly increased, and the cost of parts of the sludge scraping device and the installation cost to the sedimentation tank are increased.

  In view of the above circumstances, an object of the present invention is to provide a sludge scraping device capable of maintaining an appropriate tension even when an endless chain extends while suppressing cost.

The sludge scraping device of the present invention that solves the above-described object is provided in a sedimentation basin having a structure whose lower end portion is located below the water surface, and the sludge that has settled on the bottom of the pond is scraped by a flight plate extending in the pond width direction. In the sludge scraping device
A plurality of the flight plates are attached at intervals, and endlessly travels a circular track including a scraping track along the pond bottom and a passing track extending from the scraping track toward the water surface and passing through the vicinity of the structure. chain,
A sprocket around which a water surface side portion of the passing track in the endless chain is wound;
A rail member extending from the sprocket side to the scraping track side along the passing track between the passing track and the structure, and preventing the flight plate from contacting the structure; and
A support shaft provided on the railing track side of the rail member and supporting the rail member in a swingable manner;
The rail member has a portion on the sprocket side with respect to the support shaft that advances toward the endless chain with the support shaft as a swing center, so that the circular track is attached to a flight plate attached to the endless chain. The endless chain is contacted from the outside and tension is applied to the endless chain.

  According to the sludge scraping device of the present invention, since the endless chain is configured to apply tension to the endless chain by a rail member that is generally provided in the sludge scraping device, the endless chain can be The tension can be maintained even when stretched.

  The rail member may advance by its own weight, or may advance by the urging force of the urging member.

  The endless chain may be provided at each end of the settling basin in the pond width direction.

  In the sludge scraping device according to the present invention, it is preferable that the rail member is capable of moving forward and backward according to a tension of a passing track portion that travels on the passing track in the endless chain.

  Furthermore, the rail member may be advanced and retracted by swinging.

  Moreover, in the sludge scraping device of the present invention, when the rail member applies a predetermined tension to the endless chain, the tension of the passing track portion that travels on the passing track in the endless chain exceeds the predetermined tension. , It may be pushed back by the passing track portion and evacuated.

  By retracting the rail member due to the tension of the passing track portion, it is possible to suppress an excessive tension from being applied to the endless chain.

In the sludge scraping device according to the present invention, it is also one of preferred embodiments that the rail member has a portion in contact with the flight plate having a length equal to or longer than the interval in the direction along the passing track. .

That is, the rail member has a length in the direction along the passing track that always contacts at least one flight plate that sequentially passes through the endless chain in the passing track. May be.

  In the configuration in which the outer peripheral surface of the idle roller is brought into contact with the endless chain as in Patent Document 1, when the flight plate circulates at a position facing the idle roller, the idle roller once leaves the endless chain. You will get over the flight board. At the time of overcoming, there is a concern that the idle roller may be removed from the endless chain, and tension may not be applied to the endless chain. In addition, at the final stage of overcoming, the rail member once leaves the flight plate and comes into contact with the endless chain again to apply tension, but at that time, the tension of the endless chain suddenly changes. There is also a problem. According to the above aspect, since the rail member is always in contact with one of the flight plates that pass through the passing track portion, a constant tension can be constantly and stably applied to the endless chain.

  According to the sludge scraping device of the present invention, moderate tension can be maintained even when the endless chain is extended, while suppressing cost.

It is a sectional side view of the sedimentation basin in which the sludge scraping apparatus which is one Embodiment of this invention was installed. It is the elements on larger scale which expanded the A section of FIG. It is a top view which shows a protection mechanism. It is the schematic which shows a mode that the endless chain of the extended state is carrying out normal rotation driving | running | working of a passing track. It is the schematic which shows a mode that the endless chain of the extended state was reverse-traveled.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a side sectional view of a sedimentation basin 1 in which a sludge scraping device 10 according to an embodiment of the present invention is installed.

  A sedimentation basin 1 shown in FIG. 1 is a pond having a substantially rectangular shape in plan view, surrounded by an upstream wall 1a, a downstream wall 1b, and a pair of side walls 1c. This sedimentation basin 1 accepts sewage such as sewage and rainwater from one end side in the longitudinal direction (left side in FIG. 1), sediments sludge contained in the received sewage into the pond bottom 1d, and the other end side (right side in FIG. 1). Drain from. Hereinafter, the left direction in FIG. 1 may be referred to as upstream, and the right direction in FIG. 1 may be referred to as downstream. Moreover, the direction orthogonal to the paper surface in FIG. 1 may be referred to as a pond width direction.

  As shown in FIG. 1, the sedimentation basin 1 is provided with a sludge scraping device 10, a scum removing device 30, a drainage basin 40, and a sludge pit 50 according to this embodiment. The drainage basin 40 is provided in the downstream part of the sedimentation basin 1, and the sludge pit 50 is provided in the upstream part of the sedimentation basin 1.

  The sludge scraping device 10 according to the present embodiment is provided at each of both ends of the sedimentation basin 1 in the pond width direction, and spans between a pair of endless chains 11 traveling in the sedimentation basin 1 and the pair of endless chains 11. And a protection mechanism 13 for preventing the flight plate 12 from contacting a trough 32 described later. The pair of endless chains 11 form the same orbit around each other at both ends in the pond width direction. The endless chain 11 is a metal chain in which a plurality of link members are connected. A resin chain may be used as the endless chain 11. Each of the endless chains 11 includes a scraping trajectory T1 along the pond bottom 1d, a passing trajectory T2 extending from the scraping trajectory T1 toward the water surface W on the downstream side of the sedimentation basin 1, and a scraping trajectory T1 on the upstream side of the sedimentation basin 1. This is an annular chain forming a circular orbit in which an upstream track T3 extending toward the water surface W and a water surface track T4 connecting the upstream side and the downstream side are connected on the water surface W side. The passing trajectory T <b> 2 is a trajectory that is below the trough 32 and passes through the vicinity of the trough 32. In addition, in FIG. 1, the endless chain 11 is shown by the said circulation track | orbit.

  Sprockets 14 to 17 are arranged at the connecting portions of the tracks T1 to T4. These sprockets 14-17 are arrange | positioned inside the said circumference track. A part of the endless chain 11 is wound around each of the sprockets 14 to 17, and a portion of the endless chain 11 that is wound around each of the sprockets 14 to 17 meshes with the sprockets 14 to 17.

  The sprocket 14 is disposed at a connection portion between the upstream track T3 and the water track T4. A drive shaft 141 is fixed to the central portion of the sprocket 14. The drive shaft 141 is connected to the motor 21 by a drive chain 211. As the motor 21 rotates, the sprocket 14 also rotates via the drive shaft 141. In other words, the sprocket 14 is a driving wheel that transmits the driving force of the motor 21 and causes the endless chain 11 to travel. The motor 21 is a motor that can rotate in both the clockwise direction and the counterclockwise direction in FIG. The motor 21 is normally driven to rotate clockwise in FIG. As the motor 21 rotates, the sprocket 14 and the endless chain 11 usually run clockwise. Hereinafter, the endless chain 11 traveling clockwise in FIG. 1 is referred to as forward running. On the other hand, the motor 21 has a torque limiter function. For example, if a foreign object is caught in the flight plate 12 attached to the endless chain 11 running on the pond bottom 1d and an excessive load is applied to the motor 21, the torque limiter function is activated and the motor 21 is temporarily stopped. . Then, in order to release the foreign matter from being caught, the motor 21 rotates reversely (rotates counterclockwise in FIG. 1) for a short time. As the motor 21 rotates in the reverse direction, the endless chain travels counterclockwise in FIG. Hereinafter, the endless chain 11 traveling counterclockwise in FIG. 1 is referred to as reverse traveling.

  The other sprockets 15 to 17 are driven wheels that rotate as the endless chain 11 travels. Fixed shafts 151, 161, and 171 are passed through the central portions of the sprockets 15 to 17 of the driven wheels. The fixed shafts 151, 161, 171 are fixedly arranged so as not to rotate around the shaft. The driven wheel sprockets 15 to 17 are all rotatable with respect to the fixed shafts 151, 161 and 171. Each of the sprockets 14 to 17 rotates with the drive shaft 141 and the fixed shafts 151, 161, 171 as rotation axes.

  The flight plate 12 is attached at equal intervals in the circumferential direction over the entire circumference of the endless chain 11. A pond bottom guide rail 23 extending in the longitudinal direction of the settling basin 1 along the pond bottom 1 d is fixed to the pond bottom 1 d of the settling basin 1. The flight plate 12 attached to the endless chain 11 travels while being guided by the pond bottom guide rail 23 on the scraping track T1. Further, an upstream return rail 24 extending in the longitudinal direction of the settling basin 1 along the water surface W is fixed on the upstream side of the settling basin 1 and in the vicinity of the water surface W. The flight plate 12 attached to the endless chain 11 travels while being guided by the upstream return rail 24 in the water surface track T4. Furthermore, a downstream return rail 25 that is substantially parallel to the pond bottom 1d and extends in the longitudinal direction of the settling basin 1 is fixed at a predetermined height position downstream of the basin 1d. ing. The flight plate 12 attached to the endless chain 11 travels while being guided by the downstream return rail 25 on the downstream side in the passing track T2. However, when the endless chain 11 is traveling in the reverse direction, the flight plate 12 attached to the portion of the endless chain 11 located on the passing track T2 travels away from the downstream return rail 25. The behavior of the flight plate 12 when the endless chain 11 travels in the reverse direction will be described in detail later.

  When the endless chain 11 travels forward, the flight plate 12 travels from the downstream side toward the upstream side along the raking track T1 along the pond bottom 1d, and the sludge settled on the pond bottom 1d is It is scraped to the sludge pit 50. The sludge attracted to the sludge pit 50 is discharged outside the sedimentation basin 1 by a sludge pump (not shown).

  FIG. 2 is a partially enlarged view in which the portion A of FIG. 1 is enlarged.

  As shown in FIG. 2, the scum removing device 30 includes a weir 31 and a trough 32. The trough 32 has a U-shape with an upper end portion opened in a side view, and the lower end portion is located below the water surface W. That is, the trough 32 in the present embodiment corresponds to an example of the structure of the present invention. The trough 32 extends across the settling basin 1 in the pond width direction to a scum pit (not shown) provided outside the settling basin 1. In addition, the scum pit which protrudes inside the sedimentation basin 1 also exists, and it can be said that the part which protrudes in the sedimentation basin 1 of the scum pit is an example of a structure. The upstream side wall 321 of the trough 32 is provided with a filling port 322 for swallowing water in the vicinity of the water surface W of the sedimentation basin 1. A predetermined water level higher than the lower end portion of the insertion port 322 is the lowest water level of the sedimentation tank 1. The weir 31 is connected to the trough 32 by a connecting member 33 so as to be rotatable with respect to the trough 32 with the lower end as a rotation center. The weir 31 changes its state between a dammed state in which the upper end is located above the water surface W and a swallowed state in which the upper end is submerged in water. The weir 31 shown in FIG. 2 is in a dammed state. The weir 31 prevents the water in the sedimentation basin 1 from flowing into the trough 32 from the inlet port 322 in the dammed state. When the upper end of the weir 31 in the dammed state is pushed down by a drive mechanism (not shown), the weir 31 is rotated about the lower end as a center of rotation, and is in a pinched state.

  Scum is floating on the water surface W of the sedimentation basin 1. When the endless chain 11 travels forward, the flight plate 12 travels on the water surface track T4 from the upstream side toward the downstream side, and the scum floating on the water surface W of the settling basin 1 is transferred by the flight plate 12 toward the weir 31. Is done. When the weir 31 is in a stagnation state, the scum flows into the trough 32 over the upper end of the weir 31 together with the water in the settling basin 1. The inner bottom surface of the trough 32 is inclined downward toward a scum pit (not shown) outside the sedimentation basin 1, and the scum mixed water mixed with the scum reaches the scum pit through the trough 32.

  Further, the water in the sedimentation basin 1 from which the scum and sludge have been removed passes under the trough 32 and flows into the drainage basin 40, flows from the drainage basin 40 to a drainage channel (not shown), and is drained outside the sedimentation basin 1. The

  The protection mechanism 13 includes a pair of protection rails 18, a support shaft 19 that supports the protection rail 18 in a swingable manner, and a restriction shaft 20 that restricts the swing range of the protection rail 18. The protective rail 18 is a rail member having an arcuate shape in a side view extending in the intersecting direction intersecting the pond width direction between the passing track T2 and the trough 32. The protective rail 18 prevents the flight plate 12 attached to the portion of the endless chain 11 traveling on the passing track T2 and the trough 32 from contacting each other. A bearing 181 through which the support shaft 19 is passed is fixed to each protection rail 18. Each protection rail 18 is supported by the support shaft 19 so as to be swingable with the support shaft 19 as a swing center axis. In addition, a restriction shaft 20 is passed through one end portion (left end portion in FIG. 2) of each protection rail 18.

  FIG. 3 is a plan view showing the protection mechanism 13. In FIG. 3, an endless chain 11 and a flight plate 12 are also shown.

  As shown in FIG. 3, each protection rail 18 is arranged near the pair of side walls 1 c of the settling basin 1 and closer to the center of the pond width direction than the end surface of the flight board 12 in the pond width direction. The protective rail 18 may be arranged in another position as long as the protective rail 18 and the flight plate 12 overlap in plan view, for example, the end position of the endless chain 11 in plan view. You may arrange | position in the position which overlaps. Both end portions in the longitudinal direction of the support shaft 19 are fixed to the side walls 1c of the settling basin 1, respectively. On each side wall 1c of the settling basin 1, a regulation guide 201 having a groove 201a recessed in the pond width direction is fixed. Both ends of the restriction shaft 20 are inserted into each groove 201a. As shown in FIG. 2, the groove 201 a has a substantially sector shape when viewed from the side. By restricting the movement range of the restriction shaft 20 by the groove portion 201a, the swing range of the protective rail 18 is restricted.

  The center of gravity of the protection rail 18 is present at one end side portion (left side portion in FIG. 2) of the support shaft 19, and the control shaft 20 passed through the protection rail 18 and one end portion of the protection rail 18 is It is made of a material having a specific gravity greater than that of water (for example, stainless steel). For this reason, the weight of the protective rail 18 and the weight of the regulating shaft 20 act in a direction in which the protective rail 18 swings counterclockwise in FIG. That is, a rotational moment is generated in the protective rail 18 such that one end side portion of the protective rail 18 rotates toward the endless chain 11 with respect to the weight of the protective rail 18 and the weight of the restriction shaft 20.

  In the initial state in which the endless chain 11 is first installed in the sedimentation basin 1, the endless chain 11 is wound around the sprockets 14 to 17 in a state where an appropriate tension (for example, 100 kgf) is applied. FIG. 2 shows the initial state. The protective rail 18 is in contact with any one or two of the flight plates 12 attached to the endless chain 11 from the outside of the orbit. In the initial state, the protective rail 18 is pushed toward the outside of the circular track by the tension of the endless chain 11 and is in the retracted position retracted to the outside (the trough 32 side) of the circular track. However, the swing range of the protection rail 18 is restricted by the restriction guide 201 so that the protection rail 18 and the trough 32 do not contact each other, and a gap is provided between the protection rail 18 and the trough 32 in the retracted position. ing. Further, since the protective rail 18 is interposed between the trough 32 and the flight plate 12, a predetermined distance is maintained between the flight plate 12 and the trough 32. That is, the protection rail 18 prevents the flight plate 12 and the trough 32 from contacting each other.

  The endless chain 11 may be secularly changed due to the familiarity of the endless chain 11 or a creep phenomenon. When the endless chain 11 travels, a traveling load generated by the flight plate 12 scraping sludge is applied to the portion of the endless chain 11 located on the scraping track T1. When the endless chain 11 is traveling forward, a tension corresponding to the travel load is generated in a portion of the endless chain 11 located on the scraping track T1 and the upstream track T3. On the other hand, in the portion of the endless chain 11 that is located on the passing track T2 and the water surface track T4, the tension applied to the endless chain 11 in the initial state decreases as the endless chain 11 extends.

  FIG. 4 is a schematic diagram illustrating a state in which the endless chain 11 in an extended state travels forward on the passing track T2. In FIG. 4A, the state in which one of the flight plates 12 in the initial state is in contact with the protective rail 18 is also indicated by a two-dotted line.

  As shown in FIG. 4, the protection rail 18 swings with the support shaft 19 as a swing center axis following the extension of the endless chain 11, and comes into contact with the flight plate 12 from the outside of the orbit of the endless chain 11. Yes. The portion of the protective rail 18 that contacts the flight plate 12 advances toward the inside of the orbit by the rotational moment generated in the protective rail 18, thereby pushing the flight plate 12 and applying tension to the endless chain 11. ing.

  4A to 4C sequentially show how the endless chain 11 passes through the passing track T2 by forward running. In FIG. 4A, one of the flight plates 12 is in contact with the protective rail 18. As shown in FIG. 4 (b), in this embodiment, immediately before one of the flight plates in contact with the protective rail 18 in FIG. The next sheet attached on the downstream side in the forward running of one sheet comes into contact with the protective rail 18. Further, as shown in FIG. 4C, after one of the flight plates in contact with the protective rail 18 in FIG. One sheet passes through the trajectory T2 while contacting the protective rail. That is, the length of the portion of the protective rail 18 that contacts the flight plate 12 is configured to be longer than the interval in the circumferential direction where the flight plate 12 is arranged. With this configuration, the protective rail 18 is always in contact with at least one of the flight plates 12, and a predetermined tension is applied to the endless chain 11.

  FIG. 5 is a schematic diagram showing a state in which the endless chain 11 in the stretched state is reversely driven.

  As shown in FIG. 5, due to the reverse rotation of the motor 21, the portion of the endless chain 11 located on the passing track T <b> 2 is pulled by the sprocket 14 and is in a tension state without sagging. In this tensioned state, the tension of the endless chain 11 on the passing track T2 is larger than the tension that the protective rail 18 has applied to the endless chain 11 during forward running. For this reason, the protective rail 18 is pushed back by the flight plate 12 attached to the endless chain 11 at the portion located on the passing track T2, and is retracted to the limit of the swinging range outside the circular track. Since the swinging range of the protective rail 18 is restricted by the restriction guide 201 so as not to come into contact with the trough 32, the protective rail 18 and the trough 32 are prevented from colliding. In addition, since the flight plate 12 is maintained at a predetermined distance from the trough 32 by the protective rail 18, the flight plate 12 and the trough 32 do not collide even when traveling in reverse. In the tensioned state, the endless chain 11 is slackened on the upstream track T3.

  As described above, according to the present embodiment, tension is applied to the endless chain 11 by the protective rail 18 that prevents the flight plate 12 and the trough 32 from colliding with each other. With this configuration, it is possible to maintain an appropriate tension on the endless chain 11 that is running forward even when the endless chain 11 is extended while minimizing the increase in the number of parts. In addition, for example, when the tension of the endless chain 11 is reduced to such a degree that the endless chain 11 can be easily detached from the sprockets 14 to 17, it is necessary to adjust the tension of the endless chain 11. In the present embodiment, even if the endless chain 11 is extended, the protective rail 18 applies tension to the endless chain 11, so that it is not necessary to adjust the tension until the endless chain 11 is considerably extended. Even if it becomes necessary to perform tension adjustment, the period until the tension adjustment needs to be extended becomes longer, and the frequency of tension adjustment can be reduced.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope described in the claims. For example, in this embodiment, the protection rail 18 is configured to swing, but the entire protection rail 18 may be configured to move toward the passing track T2. Further, the rotational moment generated by the weight of the protective rail 18 and the regulating shaft 20 is used to advance the protective rail 18 and push the flight plate 12 toward the inside of the orbit. However, an urging member such as a spring is used. It is good also as a structure which provides and makes the protection rail 18 advance. In the present embodiment, the restriction guide 201 and the restriction shaft 20 are provided. However, the bearing 181 is provided with a one-way clutch or a ratchet mechanism to prevent the protection rail 18 from swinging in the direction approaching the trough 32. It is good. In addition, even if it is a structural requirement contained only in description of the modification demonstrated above, you may apply the structural requirement to another modification.

DESCRIPTION OF SYMBOLS 1 Sedimentation basin 1d Bottom of pond 10 Sludge scraper 11 Endless chain 12 Flight board 18 Protection rail 32 Trough T1 Scraper track T2 Passing track W Water surface

Claims (4)

In a sludge scraping device that is provided in a sedimentation basin having a structure in which the lower end portion is located below the water surface, and scrapes sludge settled on the bottom of the pond by a flight plate extending in the pond width direction,
A plurality of the flight plates are attached at intervals, and endlessly travels a circular track including a scraping track along the pond bottom and a passing track extending from the scraping track toward the water surface and passing through the vicinity of the structure. chain,
A sprocket around which a water surface side portion of the passing track in the endless chain is wound;
A rail member extending from the sprocket side to the scraping track side along the passing track between the passing track and the structure, and preventing the flight plate from contacting the structure; and
A support shaft provided on the railing track side of the rail member and supporting the rail member in a swingable manner;
The rail member has a portion on the sprocket side with respect to the support shaft that advances toward the endless chain with the support shaft as a swing center, so that the circular track is attached to a flight plate attached to the endless chain. A sludge scraping device, which is in contact with the outside of the endless chain and applies tension to the endless chain.   2. The sludge scraping device according to claim 1, wherein the rail member is capable of moving forward and backward according to a tension of a passing track portion that travels on the passing track in the endless chain.   While the rail member applies a predetermined tension to the endless chain, when the tension of the passing track portion traveling on the passing track in the endless chain exceeds the predetermined tension, the rail member is pushed back by the passing track portion. The sludge scraping device according to claim 1 or 2, wherein the sludge collecting device is for retreating.   4. The rail member according to claim 1, wherein a portion of the rail member that contacts the flight plate has a length equal to or longer than the interval in a direction along the passing track. Sludge scraping device.

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