JP6435497B2 - Contaminant removal screen device - Google Patents

Description

  The present invention is a contaminant removal screen for transferring the contaminants contained in the sewage that cannot pass through the interval of the screen bodies and that are contained in the sewage, upward on the upstream side of the screen body, and drop them downstream. Relates to the device.

  In the sewage treatment system, generally, sewage composed of sewage flows and is purified in the order of description of the settling basin, the first settling basin, the reaction tank, and the final settling basin. In this, for example, in the first sedimentation basin, sewage (raw sludge) containing sludge precipitated at the bottom of the pond is transferred to the outside of the first sedimentation basin by a sludge pump or the like, concentrated, dehydrated and then incinerated. Here, since the raw sludge contains impurities such as scum, generally, the contaminants are removed from the raw sludge by the contaminant removal screen device for raw sludge before being concentrated and dehydrated. The Further, sewage (scum water) containing scum of contaminants floating near the surface of the water is collected in the scum pit and then transferred from the scum pit to the outside of the first sedimentation basin by the scum pump. The scum water first transferred to the outside of the sedimentation site is returned to the sewage treatment plant after the scum is removed by the scum contaminant removal screen device. These contaminant removal screen devices are arranged in a water tank that receives raw sludge and scum water from the first sedimentation basin (see, for example, Patent Document 1).

  The foreign matter removing screen device described in Patent Document 1 has a screen body that is immersed in sewage in a water tank, an endless chain, and a plurality of rakes attached to the endless chain at intervals. In the screen body, bars extending in the vertical direction are arranged at a predetermined interval, and the screen body blocks a foreign object having a size larger than the interval. When the endless chain is driven, the contaminants blocked by the screen body are lifted up by the rake attached to the endless chain, transferred upward on the upstream side of the screen body, and then dropped to the downstream side. Discharged. In the foreign matter removing screen device described in Patent Document 1, since the rake closes the gap between the screen bodies in the sewage, the more rakes attached to the endless chain increase, the less sewage passes through the screen body. turn into. In addition, due to the strength of the endless chain, it is difficult to attach many rakes to the endless chain. For these reasons, it is necessary to increase the interval between the plurality of rakes attached to the endless chain, and contaminants such as residue are likely to accumulate near the water surface. As a result, especially in a combined sewage treatment system that collects rainwater into sewage, when a large amount of water flows into the tank due to heavy rain, etc., the level of the tank rises and the sewage overflows outside the tank. There is a case to put out.

  On the other hand, as a foreign matter removing screen device that can solve such a problem, there is known a foreign matter removing screen device called a filtration surface moving screen device (see, for example, Patent Document 2). The foreign matter removing screen device described in Patent Document 2 includes a screen body including a pair of fixed screen members and an operating screen member disposed between the pair of fixed screen members. The pair of fixed screen members are arranged such that their uppermost portions protrude from the water surface of a water tank or the like, and are provided with a plurality of fixed step portions arranged in the direction of transferring foreign substances. The operating screen member is provided with a plurality of operating steps arranged in the transfer direction of the contaminants, and moves the impurities toward the uppermost portion of the fixed screen member by moving with respect to the pair of fixed screen members. is there. The foreign matter transferred to the uppermost part of the fixed screen member falls to the downstream side and is discharged to the outside of the foreign matter removing screen device. According to the screen device of Patent Document 2, it is possible to make it difficult for impurities to accumulate near the water surface by moving the operating screen member in a short time. As a result, even when a large amount of water flows into the aquarium due to heavy rain or the like, it is possible to suppress an increase in the water level of the aquarium and prevent sewage from overflowing outside the aquarium.

Japanese Patent Laid-Open No. 8-23643 JP-A-53-132149

  However, in the screen device described in Patent Document 2, it has been found that there may occur a phenomenon in which the contaminants transferred to the uppermost part of the fixed screen member become a lump and fall downstream or upstream. did. When this phenomenon is analyzed in detail, if a lump of contaminants falls downstream, the transfer path until the contaminants are discharged may be blocked, and conversely, the drops fall upstream. As a result, it was found that the water level of the water tank etc. rose at a stretch, and the sewage leaked out of the water tank etc.

  In view of the above circumstances, an object of the present invention is to provide a foreign matter removing screen device that is devised to prevent foreign matters that have been transferred to the top of a fixed screen member from falling as a lump. To do.

The contaminant removal screen device of the present invention that solves the above-mentioned object is
A screen body having an interval connecting the upstream side and the downstream side of the received sewage, and the contaminants contained in the sewage that cannot pass through the interval and block the interval on the upstream side of the screen body, In the contaminant removal screen device that is transported upward on the upstream side of the body and dropped to the downstream side,
The screen body is
A pair of fixed screen members respectively arranged so that the uppermost portion protrudes from the surface of the received sewage,
An operating screen member for transferring impurities toward the top by moving relative to the fixed screen member between the pair of fixed screen members;
Furthermore, a deposition preventing means for preventing the contaminants transferred to the top from being deposited on the top is provided.
Each of the pair of fixed screen members is provided with a plurality of fixed step portions arranged in the direction of transferring foreign matters, and the uppermost portion has a fixing surface having a placement surface for temporarily placing the transferred foreign matters. With an upper stage,
The operation screen member is provided with a plurality of operation steps arranged in the transfer direction of the contaminants, and transfers the impurities to the fixed step portion above by the operation steps.
The deposition preventing means drives the mechanical removal member in a state where it is in contact with the mounting surface or slightly floated from the mounting surface, thereby removing residual impurities on the mounting surface. It is what makes it fall to the downstream side from.

  Further, the accumulation preventing means slides the removal blade from the upstream side to the downstream side in a state in which the removal blade is in contact with the mounting surface or slightly floated from the mounting surface, whereby residual contamination on the mounting surface is obtained. An object may be dropped from the placement surface to the downstream side.

  Alternatively, the deposition preventing means rotates the brush in a state where it is in contact with the placement surface or slightly lifted from the placement surface, thereby removing residual impurities on the placement surface from the placement surface. It may be dropped on the downstream side.

  ADVANTAGE OF THE INVENTION According to this invention, the foreign material removal screen apparatus by which the device which prevents the foreign material conveyed to the uppermost part of the fixed screen member from falling as a lump was made | formed can be provided.

It is a figure which shows typically some facilities in a sewage treatment plant. It is a front view of the screen unit for raw sludge equivalent to one Embodiment of this invention. It is a top view of the screen unit for raw sludge shown in FIG. (A) is the schematic diagram which looked at the screen body provided in the contaminant removal screen apparatus for raw sludge from the upstream of the water tank, (b) is the enlarged view which looked at the fixed uppermost step part from the width direction. Yes, (c) is a figure which shows a mode that the contaminant removal screen apparatus for raw sludge removes a contaminant in steps from a width direction. It is a figure which shows a mode that the foreign material arrived on the mounting surface, and the foreign material was mounted on the mounting surface. (A) is the figure which looked at the part which supplies water to the screen body from the nozzle of a fluid supply member from upper direction, (b) is AA sectional drawing of (a). It is a figure which shows the aspect corresponding to Fig.6 (a) about the modification of the nozzle shown to Fig.6 (a). It is a schematic diagram which shows the modification of a deposition prevention means in the state corresponding to FIG.5 (c).

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

  FIG. 1 is a diagram schematically showing some facilities in a sewage treatment plant.

  FIG. 1 shows a sedimentation basin 1, a screen unit 2 for raw sludge, a scum pit 3, and a screen unit 4 for scum.

  The sedimentation basin 1 shown in FIG. 1 accepts sewage (sewage) from one end side in the longitudinal direction (right side in FIG. 1), sediments sludge contained in the received sewage at the bottom of the pond, and the other end side (in FIG. 1). Drain from the left side. Hereinafter, the right direction in FIG. 1 is referred to as upstream, and the left direction in FIG. 1 is referred to as downstream. A sludge pit 11 is provided at the pond bottom on the upstream side of the sedimentation basin 1, and a drainage basin 12 is provided in the vicinity of the downstream water surface. In the sedimentation basin 1, the sludge settled on the bottom of the pond is collected in the sludge pit 11 by a sludge scraper (not shown). The sludge collected in the sludge pit 11 is sent to the raw sludge screen unit 2 installed outside the sedimentation basin 1 by the sludge pump 13. The sludge collected in the sludge pit 11 includes impurities such as residue. Hereinafter, the sludge containing sludge that is sent from the sludge pit 11 to the screen unit 2 for raw sludge is referred to as raw sludge. The raw sludge screen unit 2 is provided with a raw sludge contaminant removal screen device 6, and as will be described in detail later, the raw sludge contaminant removal screen device 6 provides a contaminant contained in the raw sludge. Is removed. The raw sludge from which contaminants have been removed by the raw sludge contaminant removal screen device 6 is then sent to a sludge concentration treatment facility and a sludge dewatering treatment facility. Moreover, in the sedimentation basin 1, the scum floating near the water surface is scraped to the drainage basin 12 by a scum scraper (not shown). The drainage basin 12 is connected to the scum pit 3, and the scum containing scum (scum water) is collected in the scum pit 3, and then the scum screen installed outside the sedimentation basin 1 from the scum pit 3 by the scum pump 31. Sent to unit 4. The scum water collected in the scum pit 3 also contains impurities such as residue. The scum screen unit 4 is also provided with a scum contaminant removal screen device 7, and the scum contaminant removal screen device 7 removes scum, which is a contaminant contained in the scum water. The sewage from which the scum has been removed by the scum contaminant removal screen device 7 is returned to the sewage treatment plant.

  Subsequently, the raw sludge screen unit 2 provided with the raw sludge contaminant removal screen device 6 will be described as an example, but the scum screen unit 4 provided with the scum contaminant removal screen device 7 is also described. It is the same.

  FIG. 2 is a front view of a raw sludge screen unit provided with a raw sludge contaminant removal screen device corresponding to an embodiment of the present invention.

  FIG. 3 is a plan view of the raw sludge screen unit shown in FIG. This plan view corresponds to a view when the raw sludge screen unit 2 is viewed from above.

  The screen unit 2 for raw sludge shown in FIG. 2 and FIG. 3 includes a water tank 5 and a contaminant removal screen device 6 for raw sludge. The contaminant removal screen device 6 for raw sludge includes a screen body 60 described later in detail. The screen unit 2 for raw sludge shown in FIG. 2 and FIG. 3 accepts raw sludge from the right side of the figure (see thick arrows in the figure). Hereinafter, the right side in FIGS. 2 and 3 is referred to as the upstream side, and the left side is referred to as the downstream side. Further, the direction perpendicular to the paper surface in FIG. 2 and the vertical direction in FIG. 3 may be referred to as the width direction.

  In the lower half of the side wall on the upstream side of the water tank 5 shown in FIG. 2, an inclined portion 51 that is inclined toward the downstream side toward the bottom 5a is provided, and in the lower half of the side wall on the downstream side, the bottom 5a. An inclined portion 52 that is inclined toward the upstream side as it goes toward is provided. Accordingly, the water tank 5 has a shape in which the bottom 5a side is narrowed. This water tank 5 accepts the sludge collected in the sludge pit 11 shown in FIG. 1 as raw sludge. An inflow pipe 53 is provided on the upstream side of the water tank 5. The raw sludge is supplied to the inflow pipe 53 by driving the sludge pump 13, flows into the water tank 5 from the fan-shaped tip 531 of the inflow pipe 53, and flows toward the downstream side ( (See the many thin arrows in the figure). Further, the foreign matter X such as the residue contained in the raw sludge is blocked by the screen body 60 provided in the raw sludge foreign matter removal screen device 6, and as shown in FIG. It is in a state of collecting near the water surface on the side.

  The raw sludge screen unit 2 is provided with an emergency overflow unit 54 on the upstream side of the screen body 60 in the raw sludge contaminant removal screen device 6 and a drainage overflow unit 55 on the downstream side. Both the emergency overflow unit 54 and the drainage overflow unit 55 have drainage basins 541 and 551 and barrier plates 542 and 552, and as shown in FIG. 3, any of the drainage basins 541 and 551 are arranged in the width direction of the water tank 5. It is provided to overhang. The dam plate 552 of the drainage overflow unit 55 is provided at the boundary between the water tank 5 and the drainage basin 551, and the water tank 5 and the drainage basin 551 are connected to each other above the barrier plate 552. It is not connected in a portion below the weir plate 552. When the water level of the water tank 5 exceeds the height position of the upper end of the dam plate 552, the sewage in the water tank 5 flows into the drainage 551 beyond the dam plate 552. The sewage in the water tank 5 here is raw sewage that has passed through the screen body 60, that is, sewage containing sludge from which contaminants have been removed by the sewage removal screen device 6 for raw sludge. It is sent to the sludge concentration treatment facility and sludge dewatering treatment facility that are the equipment of the treatment process. Thus, the raw sludge that has passed through the screen body 60 provided in the raw sludge contaminant removal screen device 6 is drained out of the raw sludge screen unit 2 by the drainage overflow unit 55.

  The structure of the emergency overflow unit 54 is the same as the structure of the drainage overflow unit 55, but the emergency overflow unit 54 is provided at a higher position than the drainage overflow unit 55. When the raw sludge contaminant removal screen device 6 breaks down and the water level of the water tank 5 rises from the normal water level and exceeds the weir plate 542 of the emergency overflow unit 54, the inside of the drainage 541 of the emergency overflow unit 54 Flow into. The raw sludge in the water tank 5 referred to here is raw water sludge before passing through the screen body 60, that is, sludge containing sludge before foreign matters are removed by the raw sludge foreign matter removal screen device 6, The sewage is returned to the upstream end of the raw sludge contaminant removal screen device 6.

  Next, the contaminant removal screen device 6 for raw sludge will be described in detail. As shown in FIG. 2, the raw sludge contaminant removal screen device 6 includes a screen body 60, a fluid supply member 63, a chain drive mechanism 65, and a chute 66. The chain drive mechanism 65 is driven by the rotation of the transfer motor 65m. The chute 66 has a discharge port 661 at its lower end.

  The screen body 60 is disposed in the water tank 5 in an inclined posture so that the lower part is located on the upstream side of the water tank 5 and the upper part is located on the downstream side. The uppermost part of the screen body 60 is located above the barrier plate 542 of the emergency overflow unit 54.

  As shown in FIGS. 2 and 3, the fluid supply member 63 includes a nozzle 631, a rising pipe 632 connected to the nozzle 631, and a hose portion 633. The hose part 633 is connected to a faucet (not shown), and water supplied from the faucet is discharged from the nozzle 631 through the hose part 633 and the riser pipe 632. The nozzle 631 supplies water from the upstream side to the downstream side with respect to the uppermost part of the screen body 60. As shown in FIG. 3, in the present embodiment, two nozzles 631 are provided. However, one nozzle 631 may be provided, or three or more nozzles 631 may be provided. As shown in FIG. 3, an inspection port 64 is formed above a portion where water is supplied from the nozzle 631 to the screen body 60, and an internal inspection or the like can be performed by opening the inspection door 641.

  Next, the screen body 60 will be described in detail with reference to FIG.

  Fig.4 (a) is the schematic diagram which looked at the screen body provided in the contaminant removal screen apparatus for raw sludge from the upstream of the water tank. The screen body 60 shown in FIG. 4A includes a plurality of sets of a pair of long fixed screen members 61 and a similarly long operating screen member 62 provided between the pair of fixed screen members 61. Have. That is, in the contaminant removal screen device for raw sludge, the fixed screen member 61 and the operation screen member 62 are alternately arranged with a predetermined interval W (for example, 2 mm or more and 6 mm or less) over the entire width of the water tank 5. Yes. In FIG. 4A, the central portion in the width direction of the screen body 60 is omitted for simplification of the drawing. The predetermined interval W is an interval connecting the upstream side and the downstream side, which is set based on a balance between the flow rate of raw sludge passing through the raw sludge contaminant removal screen device 6 and the size of the device. Among the contaminants contained in the raw sludge, the contaminants that could not pass the predetermined interval W are captured by the screen body 60 so as to close the predetermined interval W on the upstream side of the screen body 60.

  A plurality of fixed step portions 611 are provided on the upstream side of the fixed screen member 61 along the longitudinal direction. Further, a plurality of operating step portions 621 are provided on the upstream side of the operating screen member 62 along the longitudinal direction. Hereinafter, the uppermost operating stage portion of the operating screen member 62 is referred to as an operating uppermost stage portion 622. Here, whether it is the longitudinal direction of the fixed screen member 61 or the longitudinal direction of the operation screen member 62, as will be described later, it is in the direction of transferring impurities. That is, each of the fixed screen member 61 and the operation screen member 62 is provided with stepped steps arranged in the direction of transferring foreign substances. A fixed uppermost step 612 is provided at the uppermost portion of the fixed screen member 61. The fixed uppermost step portion 612 is made of a separate member formed wider than the fixed step portion 611, and maintains a predetermined distance from the operating screen member 62. Thereby, the predetermined interval W is maintained. In addition, the fixed uppermost step 612 is located above the surface of the sewage.

  FIG. 4B is an enlarged view of the fixed uppermost portion viewed from the width direction. In FIG. 4B, the right side is the upstream side and the left side is the downstream side.

  As shown in FIG. 4B, the fixed uppermost step portion 612 has a mounting surface 612a slightly inclined downward from the upstream side toward the downstream side, and a downstream portion of the mounting surface 612a. A steep slope 612b having a larger inclination angle than the mounting surface 612a is provided. As described above, since the fixed uppermost step portion 612 is formed wider than the fixed step portion 611, both the mounting surface 612 a and the steep slope 612 b are wider than the fixed step portion 611.

  Next, the removal of contaminants in the raw sludge contaminant removal screen device 6 will be described.

  FIG.4 (c) is a figure which shows a mode that the contaminant removal screen apparatus 6 for raw sludge removes a contaminant from the width direction in steps. In FIG. 4 (c), raw sludge flows from the right side to the left side of each of the screen bodies 60 shown in (a) to (e) (see thick arrows in the figure). Accordingly, in the drawing, the right side of each of the screen bodies 60 shown in (a) to (e) is the upstream side, and the left side is the downstream side.

  In FIG. 4C, (a) shows a state in which the operating screen member 62 is in the initial position. The lower part of the fixed screen member 61 is in contact with the bottom part 5 a of the water tank 5, and the lower part of the operating screen member 62 in the initial position is also in contact with the bottom part 5 a of the water tank 5. As a result, when viewed from the width direction, they are overlapped except for the uppermost fixed portion 612 of the fixed screen member 61. In addition, a fixed step portion 611 which is the ninth step from the bottom of the adjacent fixed screen member 61 from the operation step portion 621 of the ninth step from the bottom in the operation screen member 62 shown in FIG. The foreign object X is caught in. The height position of the operation step portion 621 that is the ninth step from the bottom of the operation screen member 62 shown in (a) and the height position of the fixed step portion 611 that is the ninth step from the bottom of the fixed screen member 61 are one. I'm doing it. Further, a foreign matter X ′ is caught from the uppermost operating step 622 of the operating screen member 62 shown in FIG. 5A to the fixed step 611 at the same height position of the adjacent fixed screen member 61. Further, a contaminant X ″ is placed on the placement surface 612a of the fixed uppermost step 612 in the fixed screen member 61 shown in FIG.

  The operating screen member 62 is moved with respect to the fixed screen member 61 when the chain driving mechanism 65 shown in FIG. 2 is driven. The operation screen member 62 shown in (a) moves upward and upstream with respect to the fixed screen member 61, and the operation uppermost step 622 of the operation screen member 62 protrudes upward from the mounting surface 612a. The state has changed. As a result, the contaminant X ′ caught on the operation uppermost step 622 of the operation screen member 62 moves upward from the placement surface 612a, while the contaminant X ″ placed on the placement surface 612a is Then, it is pushed by the operating screen member 62 and slides down the steep slope 612b (see thin arrows in the figure). Further, the operating screen member 62 shown in (c) is moved upward by one step with respect to the fixed screen member 61. When viewed from the width direction, the operating screen member 62 is fixed except for the upper end portion and the lower end portion. It overlaps the screen member 61. That is, the height position of the operation step portion 621 that is the ninth step from the bottom of the operation screen member 62 shown in (c) is the height position of the fixed step portion 611 that is the tenth step from the bottom of the fixed screen member 61. The foreign matter X is lifted by one step by the operation screen member 62 and is caught by the fixed step portion 611 that is the tenth step from the bottom of the fixed screen member 61. In this way, the foreign matter X caught in the ninth stage operating stage 621 is moved further downstream in the movement direction of the operating screen member 62 than the ninth stage operating stage 621 as the operating screen member 62 moves. To the 10th fixed stage 611.

  The operating screen member 62 shown in (d) places the contaminant X ′ on the mounting surface 612a while leaving the contaminant X on the fixed step portion 611 which is the tenth step from the bottom of the fixed screen member 61. After that, it moves downward and downstream from the operation screen member 62 shown in (c). Here, as described above, since the width of the mounting surface 612a is formed wider than the width of the fixed step portion 611, the contaminant X transferred to the mounting surface 612a and mounted on the mounting surface 612a. 'Can be prevented from falling to the upstream side and returning. Further, when viewed from the width direction, the operation screen member 62 shown in (e) overlaps with the fixed screen member 61 except for the uppermost fixed portion 612 of the fixed screen member 61. That is, the operation screen member 62 shown in (e) has returned to the initial position. The operation of the operation screen member 62 from (a) to (e) shown in FIG. 4 (c) is completed by one rotation of the chain member in the chain drive mechanism 65 shown in FIG. The driving of the screen member 62 in one cycle is repeatedly performed about 13 times per minute, for example. Hereinafter, the period during which the operating screen member 62 repeats movement may be referred to as an operating period.

  As described above, during the operation period, the foreign matter X is transferred to the upper stage of the fixed step portion 611 on the upstream side of the screen body 60, and finally the placement surface from the operation uppermost step portion 622. Once placed on 612a, it slides down steep slope 612b. Note that the impurities placed on the placement surface 612a may slide down the steep slope 612b from the placement surface 612a without staying on the placement surface 612a. A chute 66 shown in FIG. 2 is arranged on the downstream side of the screen body 60, and the foreign matter that has slipped down the steep slope 612 b is put out of the raw sludge foreign matter removal screen device 6 from the discharge port 661 of the chute 66. Discharged.

  Here, the foreign matter placed on the placement surface 612a may not be dropped to the downstream side only by driving the operation screen member 62, and the foreign matter may accumulate on the placement surface 612a. With reference to FIG. 5, a description will be given of a situation where a foreign substance has reached the placement surface 612a and the foreign substance has been placed on the placement surface 612a.

  FIG. 5 is a diagram showing in a stepwise manner how the foreign matter arrives on the placement surface and the foreign matter is placed on the placement surface. In FIG. 5, the left-right direction is the width direction.

  FIG. 5A shows a state in which a part near the uppermost portion of the screen body is viewed from the upstream side in the state of FIG. 4C, and FIG. ) To (D) of FIG. 4C are shown. FIG. 5C shows a state in which the operating screen member 62 is rotated once and returned to (c) in FIG. 4C again. In FIG. 5A, the operation uppermost stage 622 protrudes upward from the placement surface 612a. In FIG. 5B, the operation uppermost stage 622 descends from the placement surface 612a. State. Moreover, in FIG.5 (c), the operation top step part 622 has returned to the state which protruded upwards rather than the mounting surface 612a again. That is, the operation uppermost step portion 622 of the operation screen member 62 moves while being sandwiched between the mounting surfaces 612a of the pair of fixed screen members 61, so that the operation screen member 62 protrudes above the mounting surface 612a. The state changes between a state where the surface is lowered from the surface 612a.

  In the state where the operation uppermost stage 622 shown in FIG. 5A protrudes upward from the placement surface 612a, the contaminant X is caught on the plurality of operation uppermost stages 622. The contaminant X in this state is at a position higher than the placement surface 612a. When the operation screen member 62 moves downward and downstream with respect to the fixed screen member 61 and the operation uppermost step 622 is lowered from the placement surface 612a as shown in FIG. Is placed on the placement surface 612a. Further, a part x1 of the contaminant X is dragged into the moving operation screen member 62, and the part x1 is interposed between the fixed uppermost step 612 and the operation screen member 62 as shown in FIG. It may get in. In a state where a part x1 of the foreign matter X has entered between the fixed uppermost step portion 612 and the operation screen member 62, the operation uppermost step portion 622 shown in FIG. 5C is above the placement surface 612a. , The foreign matter X located immediately above the operation uppermost stage 622 falls to the downstream side. However, a part x1 of the contaminant X may be caught between the fixed uppermost step 612 and the operation screen member 62, and the contaminant X may remain on the placement surface 612a. When the foreign matter X remains on the placement surface 612a, the foreign matter X accumulates on the placement surface 612a and eventually becomes a lump, which is downstream or upstream of the screen body 60. Will fall down. As described above, when the foreign matter X becomes a lump and falls to the downstream side of the screen body 60, the discharge port 661 of the chute 66 may be blocked. On the other hand, if the foreign matter X becomes a lump and falls to the upstream side of the screen body 60, the water level of the water tank 5 rises all at once, and sewage may leak out of the water tank 5.

  For this reason, in the contaminant removal screen device 6 for raw sludge of this embodiment, the fluid supply member 63 is provided as a deposition preventing means for preventing the contaminant X from accumulating on the placement surface 612a.

  FIG. 6A is a view of a portion for supplying water from the nozzle of the fluid supply member to the screen body from above, and FIG. 6B is a cross-sectional view taken along the line AA of FIG. . In FIG. 6, the right side is the upstream side and the left side is the downstream side. In FIG. 6A, the vertical direction is the width direction, and in FIG. 6B, the direction orthogonal to the paper surface is the width direction. In order to simplify the drawing, in FIG. 6, the rising pipe and the hose portion in the fluid supply member are omitted, and one nozzle 631 of the two nozzles 631 shown in FIG. 3 is shown.

  As shown in FIG. 6 (a), the nozzle 631 has discharge portions 631a and 631a branched into two, and each discharge portion from the upstream side toward the downstream side during the operation period of the operation screen member 62. Water is supplied from 631a. In addition, it is good also as an aspect which has the one discharge part 631a with respect to one nozzle 631, and is good also as an aspect which has the 3 or more discharge parts 631a. As shown in FIG. 6A, each discharge portion 631a is directed between the fixed uppermost step portion 612 and the fixed uppermost step portion 612, that is, the operation uppermost step portion 622, and in the height direction. As shown in FIG. 6B, the uppermost portion of the fixed uppermost step portion 612 is directed to the upper end portion on the upstream side. Accordingly, in FIG. 5C, water is supplied from the discharge unit 631a toward the region a surrounded by the dashed-dotted ellipse. This area a is an area including the boundary between the operation uppermost stage 622 and the placement surface 612a. As described above, during the operation period, along with the movement of the operation screen member 62, by supplying water toward the region a, the foreign matter X caught between the fixed uppermost step 612 and the operation screen member 62. Part X1 of the slag is lost, and the foreign matter X remaining on the placement surface 612a is likely to fall downstream. As a result, the residue X is not repeatedly left on the placement surface 612a, and the contamination X can be prevented from being deposited on the placement surface 612a.

  Further, if a part of the contaminant X remaining on the placement surface 612a flows downstream, the contaminant X as a whole is easily dropped to the downstream side because it is connected to the part. If water is supplied so as to hit a part of the contaminant X remaining on the placement surface 612a, it is possible to prevent the accumulation of the contaminant X. For this reason, even if it is other than the region a in FIG. 5C, water is supplied toward the foreign matter X remaining on the placement surface 612a (see the region b surrounded by the dashed-dotted line). You may make it the aspect to do. In addition, each discharge part 631a is comprised so that the direction which supplies water can be adjusted freely by bending itself. Further, it is possible to adopt a mode in which the discharge unit 631a is rotated in the width direction or the vertical direction by an actuator or the like, and water is supplied to a wide range of the screen body 60.

  Here, it is preferable to supply water from each discharge part 631a with the pressure of 0.05 MPa or more and 0.2 MPa or less. When the pressure of the supplied water is less than 0.05 MPa, the action of dropping the foreign matter X remaining on the placement surface 612a to the downstream side is too weak. On the other hand, even if the pressure of the supplied water exceeds 0.2 MPa, the action of dropping the foreign matter X remaining on the placement surface 612a to the downstream side is not so much uneconomical. In this embodiment, water is supplied from each discharge part 631a at a pressure of about 0.1 MPa, for example. Moreover, water is supplied from each discharge part 631a only for several minutes in the operation period 1 hour of the operation screen member 62. That is, the period during which the fluid supply member 63 that is the deposition preventing means acts is shorter than the operation period of the operation screen member 62, and the fluid supply member 63 is operated during this operation period. The water supplied from the nozzle 631 is discharged out of the raw sludge contaminant removal screen device 6 from the discharge port 661 of the chute 66 shown in FIG. For this reason, if the period which supplies water from the discharge part 631a becomes long, the quantity of the water supplied from this discharge part 631a will increase, and the process of the water will become difficult, and is unpreferable. In this embodiment, water is used as the fluid supplied from the fluid supply member 63 in consideration of easy procurement in the sewage treatment system. However, instead of the mode of supplying water, the water is pressurized to a predetermined pressure. Alternatively, a gas such as air may be supplied. Thus, if it is set as the aspect which supplies gas from the fluid supply member 63, the process of the supplied gas becomes unnecessary.

  Next, a modified example of the raw sludge contaminant removal screen device 6 shown in FIGS. 1 to 6 will be described. In the modified example described below, the difference from the embodiment shown in FIGS. 1 to 6 will be mainly described, and the component having the same name as the component in the embodiment shown in FIGS. The description will be given with the reference numerals used so far, and redundant description may be omitted.

  FIG. 7 is a view showing a mode corresponding to FIG. 6A for a modified example of the nozzle shown in FIG. Also in FIG. 7, the vertical direction is the width direction, the right side is the upstream side, and the left side is the downstream side.

  In the modification shown in FIG. 7, two second nozzles 634 are provided in place of the nozzle 631 shown in FIG. The second nozzle 634 has a fan shape in plan view, and a connection portion 634a to which the rising pipe 632 shown in FIG. 2 is connected is provided at a position corresponding to the main part of the fan. The water supplied to the connection portion 634a flows in a direction in which the fan spreads from the connection portion 634a, and flows down between the fixed uppermost step portion 612 and the fixed uppermost step portion 612, that is, toward the operation uppermost step portion 622 (in the drawing). (See arrow on). In the second nozzle 634 of this modification, although the pressure of water supplied to the screen body 60 is weaker than that of the nozzle 631 shown in FIG. 6A, water can be supplied to a wide range of the screen body 60. Thus, it is possible to prevent foreign matter from accumulating on the mounting surface 612a.

  Here, even in the nozzle 631 shown in FIG. 6A, water can be supplied to a wide area of the screen body 60 by providing a plurality of discharge portions 631a. However, according to the 2nd nozzle 634 shown in FIG. 7, compared with the nozzle 631 shown to Fig.6 (a), water can be supplied to the wide range in the screen body 60 by a simpler structure. Note that, similarly to the nozzle 631 shown in FIG. 6A, a gas having a predetermined pressure may be supplied from the second nozzle 634 instead of water.

  Subsequently, a modified example of the deposition preventing means will be described.

  In the embodiment and the modification described so far, the fluid supply member that supplies water or gas to the screen body 60 is used as the deposition preventing means, but the deposit that remains on the mounting surface. A member that mechanically removes may be used as the deposition preventing means.

  FIG. 8 is a schematic diagram showing a modification of the deposition preventing means in a state corresponding to FIG. In FIG. 8, the left-right direction is the width direction, the front side of the paper is the upstream side, and the back side of the paper is the downstream side.

  In the first modification of the deposition preventing means shown in FIG. 8A, a comb-shaped member 67 is employed as the deposition preventing means. The comb-shaped member 67 has a plurality of removal blades 671 provided in the width direction at intervals slightly wider than the width of the operation uppermost step 622. In the first modification of the deposition preventing means, the comb-shaped member 67 is in a state where the lower end portion of the removal blade 671 is in contact with the mounting surface 612a of the fixed uppermost step 612 or is slightly lifted from the mounting surface 612a. Then, it is slid from the upstream side to the downstream side by a driving means (not shown). As a result, the contaminant X remaining on the placement surface 612a can be dropped from the placement surface 612a to the downstream side to prevent the accumulation of the contaminant X. The comb-shaped member 67 may be made of metal or resin, but is elastic such as rubber so that the mounting surface 612a is not damaged even if it contacts the mounting surface 612a or the operation uppermost step 622. It may be made of a high material. Further, rubber or the like may be attached to the tip portion of the removal blade 671.

  In the second modification of the deposition preventing means shown in FIG. 8B, a rotating brush body 68 is employed as the deposition preventing means. The rotating brush body 68 includes a plurality of brushes 681 and a shaft member 682. Each of the plurality of brushes 681 has a large number of fibers 681a on the outer peripheral portion, and a shaft member 682 passes through the central portion of each of the plurality of brushes 681. In addition, each of the plurality of brushes 681 is arranged in the width direction with an interval slightly wider than the width of the operation uppermost step 622. In the rotating brush body 68, the shaft member is rotated by a driving unit (not shown), so that the plurality of brushes 681 are also rotated. In the second modification of the deposition preventing means, the rotating brush body 68 is not shown in a state in which the fibers 681a are in contact with the mounting surface 612a of the fixed uppermost step 612 or slightly floated from the mounting surface 612a. The brush 681 is rotated by the driving means. As a result, the contaminant X remaining on the placement surface 612a can be dropped from the placement surface 612a to the downstream side to prevent the accumulation of the contaminant X.

  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 the above-described embodiment, the raw sludge contaminant removal screen device 6 and the scum contaminant removal screen device 7 provided in the raw sludge screen unit 2 have been described as examples. The present invention can be applied not only to treatment facilities but also to facilities that treat water such as industrial water and agricultural water. In the above-described embodiment, the dust removal screen device installed in the water tank 5 has been described as an example. However, the dust removal screen device may be installed in sewage flowing through the flow path.

In the above description,
A screen body having an interval connecting the upstream side and the downstream side of the received sewage is provided, and the contaminants contained in the sewage that cannot pass through the interval and block the interval on the upstream side of the screen body are removed from the screen. In the contaminant removal screen device that is transported upward on the upstream side of the body and dropped to the downstream side,
The screen body
A pair of fixed screen members respectively arranged so that the uppermost portion protrudes from the surface of the received sewage,
An operation screen member for transferring impurities toward the uppermost part by moving relative to the fixed screen member between the pair of fixed screen members;
Furthermore, a foreign matter removing screen device is provided with a deposition preventing means for preventing the foreign matter transferred to the uppermost portion from being deposited on the uppermost portion.
Explained.

  Here, the deposition preventing means may be a member that mechanically removes the contaminants transferred to the uppermost part from the uppermost part. It may be a mechanism for preventing impurities from accumulating. The received sewage may flow from the upstream side to the downstream side in the water tank, or may flow through a predetermined water channel. Further, the foreign matter removing screen device may be a so-called filter surface moving screen device. Further, the period during which the accumulation preventing means acts may be shorter than the period during which the operation screen member repeats movement (operation period). Further, the accumulation preventing means may be operated during the operation period.

  According to the foreign matter removal screen device, the foreign matter transferred to the uppermost portion can be prevented from being deposited on the uppermost portion by the accumulation preventing means. As a result, it is possible to prevent foreign matter from accumulating on the uppermost portion, and the accumulated foreign matter to become a lump and fall to the downstream side or the upstream side. As a result, it is possible to suppress the blocking of the transfer path from the uppermost part until the contaminants fall as a lump to the downstream side and the contaminants are discharged. In addition, it is also possible to prevent the water level of the water tank or the like from rising all at once due to the impurities falling from the top as a lump to the upstream side.

Further, in the contaminant removal screen device, the pair of fixed screen members are each provided with a plurality of fixed steps arranged in the transfer direction of the contaminants,
The operating screen member may be configured to transfer impurities toward a fixed uppermost step provided at the uppermost portion.

  Further, in the contaminant removal screen device, the accumulation preventing means is a fluid supply member that supplies fluid from the upstream side to the downstream side with respect to the contaminants transferred to the fixed uppermost stage. Also good.

  Here, the fluid supply member may have a nozzle that supplies water pressurized to a predetermined pressure or a gas pressurized to a predetermined pressure, or has a nozzle that allows water to flow down. There may be. In the case of the latter nozzle, water may flow down in a fan shape from a plurality of parts.

  By carrying out like this, it can prevent with the simple structure that the foreign material transferred to the said uppermost part accumulates on the uppermost part.

Furthermore, in the foreign matter removing screen device, the working screen member is provided with a plurality of working steps arranged in the moving direction of the foreign matter, and the foreign matter is transferred by the working steps to the fixed step above. Is,
The fixed uppermost part is provided with a placement surface on which the transferred contaminants are once placed,
The uppermost operating uppermost portion of the operating screen member that moves between the pair of fixed screen members moves while being sandwiched between the upper mounting surfaces of the pair of fixed screen members. The state changes between a state protruding above and a state falling below the placement surface,
The fluid supply member may supply fluid toward a region including a boundary between the operation uppermost stage and the placement surface.

  Here, the fixed uppermost step portion may be formed wider than the other fixed step portions. Further, the fixed uppermost step portion may maintain a predetermined distance from the screen member.

  According to the above aspect, the foreign matter once placed on the placement surface changes its state from the state where the uppermost stage of the operation protrudes downward from the state of lowering the placement surface. The foreign matter placed on the placement surface falls downstream. Here, when the state of the uppermost stage of the operation changes from a state protruding above the placement surface to a lowered state, a part of the foreign matter placed on the placement surface is It may be dragged between the uppermost stage of operation and its mounting surface. However, when the fluid is supplied from the fluid supply member toward a region including the boundary between the uppermost operation stage and the placement surface, the fluid supply member is placed between the uppermost operation part and the placement surface. The foreign object with the portion dragged in can also be dropped downstream without being deposited on the placement surface.

  In addition, even if it is a structural requirement contained only in each description of embodiment and the modification demonstrated above, you may apply the structural requirement to another embodiment and a modification.

2 Screen unit for raw sludge 4 Screen unit for scum 5 Water tank 6 Contaminant removing screen device for raw sludge 7 Screen device for removing foreign matter for scum 60 Screen body 61 Fixed screen member 611 Fixed step portion 612 Fixed uppermost step portion 612a Mounting surface 62 Operation screen member 621 Operation step portion 622 Operation uppermost step portion 63 Fluid supply member 631 Nozzle X Contaminant

Claims (3)

A screen body having an interval connecting the upstream side and the downstream side of the received sewage, and the contaminants contained in the sewage that cannot pass through the interval and block the interval on the upstream side of the screen body, In the contaminant removal screen device that is transported upward on the upstream side of the body and dropped to the downstream side,
The screen body is
A pair of fixed screen members respectively arranged so that the uppermost portion protrudes from the surface of the received sewage,
An operating screen member for transferring impurities toward the top by moving relative to the fixed screen member between the pair of fixed screen members;
Furthermore, a deposition preventing means for preventing the contaminants transferred to the top from being deposited on the top is provided.
Each of the pair of fixed screen members is provided with a plurality of fixed step portions arranged in the direction of transferring foreign matters, and the uppermost portion has a fixing surface having a placement surface for temporarily placing the transferred foreign matters. With an upper stage,
The operation screen member is provided with a plurality of operation steps arranged in the transfer direction of the contaminants, and transfers the impurities to the fixed step portion above by the operation steps.
The deposition preventing means drives the mechanical removal member in a state where it is in contact with the mounting surface or slightly floated from the mounting surface, thereby removing residual impurities on the mounting surface. A screen for removing foreign substances characterized in that the screen is dropped to the downstream side.   The accumulation preventing means slides the removal blade from the upstream side to the downstream side in a state where it is in contact with the mounting surface or slightly floated from the mounting surface, thereby removing residual impurities on the mounting surface. The foreign matter removing screen device according to claim 1, wherein the screen is dropped from the placement surface to the downstream side.   The accumulation preventing means rotates the brush in a state where it is in contact with the placement surface or slightly floated from the placement surface, thereby removing residual impurities on the placement surface downstream from the placement surface. The foreign matter removing screen device according to claim 1, wherein the foreign matter removing screen device is dropped.