JP2016209817A - Sludge scraper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge scraper which is prevented from being overloaded even when the scraping of a large amount of stacks and an intermittent operation are performed without using a drive unit having a large capacity.SOLUTION: A sludge scraper includes: a driving wheel 3; driven wheels 4, 5; a drive unit 15 rotating the driving wheel 3; a pair of endless chains 7 supported by the driving wheel 3 and the driven wheels 4, 5; and a plurality of flight plates 8 mounted to the chains 7. The array of the plurality of flight plates 8 is constituted with at least a short interval section arrayed with the flight plates 8 at short intervals and a long interval section arrayed with the flight plates 8 at longer intervals than the short interval section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sludge scraping machine for scraping sludge in a settling basin to a sludge pit in a settling basin for precipitating sludge contained in raw water (treated water) such as clean water and sewage.

  In water treatment such as clean water and sewage, a sedimentation basin is used to separate sludge contained in water as a sediment. In the sedimentation basin, sludge settles by its own weight and accumulates as sediment on the bottom of the sedimentation basin. Therefore, in order to discharge the sludge from the sedimentation basin, a sludge scraper is used to scrape the accumulated sludge into a sludge pit provided at one end of the bottom surface of the sedimentation basin.

JP 2013-52331 A

  The apparent density of sludge accumulated in the sedimentation basin in the water purification process is close to the density of water, and the sludge scraping load is usually small. However, when raw water with high turbidity flows in, the load may temporarily increase. Therefore, the sludge scraper requires a drive device with large power. The link belt type scraper is normally operated continuously, but intermittent operation is performed to prevent the sediment sludge from rising during scraping, to discharge the precipitated sludge at a higher concentration, and to save energy. Sometimes. In this case, there is a possibility that the drive device is overloaded by sludge load or the scraping chain is broken.

  The sludge scraper for the sedimentation basin used at the water purification plant has a vertical scraper system that rakes toward the upstream side in parallel to the direction of the water flow in the sedimentation basin, and a lateral scraping system that scrapes the sludge so as to be orthogonal to the water flow There is. Particularly in the case of the vertical scraping method, the distance for scraping sludge is long, and overloading tends to occur when intermittent operation is performed. Also, even in the lateral scraping method, the amount of accumulation on the upstream side is large, and overload tends to occur.

  The present invention has been made in view of the above-described circumstances, and provides a sludge scraper that does not overload even when a large amount of sediment is scraped or intermittently operated without using a large-capacity driving device. The purpose is to do.

  In order to achieve the above-described object, an aspect of the present invention includes a driving wheel and a driven wheel, a driving device that rotates the driving wheel, and a pair of endless chains supported by the driving wheel and the driven wheel. And a plurality of flight plates attached to the chain, the arrangement of the plurality of flight plates is a short interval section where the flight plates are arranged at a short interval, and the interval longer than the short interval interval A sludge scraping machine comprising at least a long interval section in which flight plates are arranged.

A plurality of the short interval sections and the long interval sections are provided.
The driven wheel is composed of a first driven wheel adjacent to a sludge pit formed at the bottom of a sedimentation basin and a second driven wheel arranged farther from the sludge pit than the first driven wheel. The driven shaft for supporting the first driven wheel is supported by a swing arm so as to be movable in the vertical direction.
The swing arm is rotatably connected to a drive shaft to which the drive wheel is fixed.

A chain guard having an arc surface along the outer periphery of the first driven wheel is further provided.
A chain guard having an arc surface along the outer periphery of the drive wheel is further provided.
A sensor target attached to at least one of the plurality of flight plates and a detection sensor for detecting the sensor target are further provided.
An operation control unit that intermittently operates the driving device is further provided.
The operation control unit stops the driving device when a preselected section of the short interval section and the long interval section is located near or above a sludge pit formed at the bottom of a sedimentation basin. It is characterized by that.

  According to the present invention, there are at least two sections, ie, a short-interval section and a long-interval section, which have different flight board arrangement intervals. In the long interval section, since the number of flight plates is small, the sludge scraping load is reduced, and an overload of the drive device can be prevented. On the other hand, in the short interval section, since the sludge is scraped by more flight plates than in the long interval section, the amount of sludge scraping can be ensured.

It is a schematic side view of the sludge scraping machine which concerns on one Embodiment of this invention. It is a figure which shows the state which the operation control part stopped the drive device, when a short interval area is located in the vicinity of sludge pit or above. It is a figure which shows the state which the operation control part stopped the drive device, when the long space | interval area was located in the vicinity of sludge pit or above. It is a figure which shows the example of the combination pattern of a short interval area and a long interval area. It is the figure which looked at the drive wheel and the 1st driven wheel from the front. It is a figure which shows the state which the 1st driven wheel moved to the upper direction. It is a schematic diagram which shows other embodiment of a sludge scraper.

  FIG. 1 is a schematic side view of a sludge scraper according to an embodiment of the present invention. As shown in FIG. 1, the sludge scraper is disposed in a sedimentation basin 1 for sedimenting sludge in raw water and depositing it as a sediment. A plurality of inlets 2 for introducing raw water (treated water) into the sedimentation basin 1 are provided on the wall of the sedimentation basin 1. The raw water flowing in through the inflow port 2 flows toward the opposite wall. In the process of the raw water flowing through the sedimentation basin 1, the sludge contained in the raw water settles and accumulates at the bottom of the sedimentation basin 1. A sludge pit (sludge collection recess) 1 a for collecting sludge is formed at the bottom of the sedimentation basin 1. This sludge pit 1 a is provided below the inflow port 2.

  The sludge scraper includes a pair of drive wheels 3, first driven wheels 4, and second driven wheels 5 disposed inside the sedimentation basin 1, and a pair of these wheels 3, 4, 5. An endless chain 7 and a plurality of flight plates 8 fixed to the chain 7 at a predetermined interval are provided. Both ends of each flight plate 8 are fixed to a pair of chains 7, respectively. The drive wheel 3 is connected to the drive device 15 via the drive chain 11, and the drive wheel 3 is rotated by the drive device 15. For example, an electric motor is used as the driving device 15.

  The first driven wheel 4 and the second driven wheel 5 are disposed in the vicinity of the bottom of the settling basin 1. The first driven wheel 4 is disposed in the vicinity of the sludge pit 1 a of the sedimentation basin 1. The second driven wheel 5 is arranged farther from the sludge pit 1 a than the first driven wheel 4. More specifically, the second driven wheel 5 is disposed in the vicinity of the wall opposite to the wall on which the inflow port 2 is provided. In the present embodiment, the first driven wheel 4 and the second driven wheel 5 are provided only near the bottom surface, but a driven wheel may be further provided near the water surface.

  When the drive wheel 3 is rotated by the drive device 15, the chain 7 supported by the drive wheel 3 and the driven wheels 4, 5 circulates, and a plurality of flight plates 8 fixed to the chain 7 together with the chain 7 are settling basins. Circulate in 1. A chain 7 extending between the driven wheels 4, 5 moves along the bottom of the settling basin 1. Therefore, the flight board 8 scrapes the sludge accumulated on the bottom toward the sludge pit 1a while traveling toward the sludge pit 1a along the bottom of the sedimentation basin 1. Such a flight plate 8 is also called a scraping plate. A guide rail 19 is arranged in the sedimentation basin 1 to support the chain 7 extending between the drive wheel 3 and the second driven wheel 5. The sludge scraping machine of the present embodiment is a vertical scraping system that scrapes sludge toward the upstream side in parallel with the direction of water flow in the sedimentation basin 1.

  The driving device 15 is connected to an operation control unit 21 that controls the operation via a signal line 22. The operation control unit 21 is configured to cause the drive device 15 to operate continuously or intermittently. In the continuous operation, the flight board 8 continuously travels and scrapes the sludge on the bottom of the sedimentation basin 1. In the intermittent operation, the flight board 8 travels intermittently at predetermined time intervals. That is, the flight board 8 scrapes the sludge to the sludge pit 1a during a predetermined operation time, and thereafter the travel of the flight board 8 stops during a predetermined pause time. In the intermittent operation, the sludge scraping operation of the flight board 8 and the traveling stop of the flight board 8 are alternately repeated. The intermittent operation is performed to prevent the sludge from rising when the sludge is scraped, to discharge the precipitated sludge at a higher concentration, and to save energy.

  In the intermittent operation, as described above, there is a downtime during which the sludge rake is not performed. If a large amount of sludge settles at the bottom of the settling basin 1 during this downtime, an excessive load may be applied to the drive device 15 or the chain 7 when the sludge scraping operation is resumed. Therefore, in order to prevent an overload at the start of the sludge scraping operation, the flight plates 8 are arranged in a short interval section where the flight plates 8 are arranged at short intervals and at a longer interval than the short interval interval. Are arranged in a long interval section. Here, “short interval” does not mean shorter than a certain absolute reference interval, but means shorter than the arrangement interval of the flight plates 8 in the long interval section.

  In the present embodiment, there are two short interval intervals and two long interval intervals, and the short interval interval and the long interval interval are alternately provided. In the long interval section, since the number of flight plates 8 is small, the sludge scraping load is reduced, and the overload of the driving device 15 can be prevented. On the other hand, in the short interval section, the sludge is scraped by more flight plates 8 than in the long interval section, so that the amount of sludge scraping can be ensured.

  The operation control unit 21 is configured to stop the drive device 15 when a preselected section of the short interval section and the long interval section is positioned near or above the sludge pit 1a. For example, as shown in FIG. 2, when there is a lot of rain such as in summer and sludge is accumulated on the entire bottom of the sedimentation basin 1, the sludge scraping load is high, and the sludge is quickly scraped to the sludge pit 1a. Therefore, when the short interval section is located near or above the sludge pit 1a, the operation control unit 21 stops the drive device 15. Since the flight board 8 constituting the short interval section can quickly scrape the sludge to the sludge pit 1a at short time intervals, the sludge scraping load can be quickly reduced.

  On the other hand, for example, as shown in FIG. 3, when there is little rain and there is a lot of sludge in the vicinity of the sludge pit 1a, such as in winter, the sludge scraping load itself decreases, so the long interval section When located near or above the sludge pit 1a, the operation control unit 21 stops the driving device 15. In the long interval section, the sludge scraping frequency by the flight plate 8 is reduced, so that the peak load can be reduced.

  The short interval section and the long interval section can be arbitrarily combined based on the length of the sedimentation basin 1 and the properties of the raw water. FIG. 4 is a diagram illustrating an example of a combination pattern of a short interval section and a long interval section. The combination pattern 1 is composed of a combination of one short interval section and one long interval section. The combination pattern 2 is the combination pattern shown in FIG. 1, and is composed of a combination of two short interval sections and two long interval sections. You may be comprised from the combination of 3 or more short interval area and 3 or more long interval area.

  The combination pattern 3 includes a combination of a short interval section and a long interval section plus a medium interval section. This middle interval section is an interval in which the flight plates 8 are arranged at an interval longer than the short interval interval and at an interval shorter than the long interval interval. In the illustrated example, the short interval section, the intermediate interval section, and the long interval section are arranged in this order, but may be arranged in other orders.

  The combination pattern 4 is composed of a combination of a short interval section, a medium interval section, and a long interval section plus a dense interval section. This dense interval section is an area in which the flight plates 8 are arranged at an interval shorter than the short interval section. In the illustrated example, the first medium interval section, the short interval section, the dense interval section, the second intermediate interval section, and the long interval section are arranged in this order, but may be arranged in other orders. .

  Thus, based on the length of the sedimentation basin 1 and the property of raw | natural water, several types of area where the flight board 8 is arrange | positioned at a different space | interval can be combined suitably. Also, the length of each section can be set as appropriate. For example, the short interval section may be shorter or longer than the long interval section, or may be the same length as the long interval section.

  The amount of sludge scraped when the chain 7 makes one turn depends on the total number of flight plates 8 attached to the chain 7. When a plurality of combination patterns are formed without changing the amount of sludge scraping, the number of flight plates 8 in each section may be changed while keeping the total number of flight plates 8 attached to the chain 7 constant. For example, in the combination pattern 1, when the number of flight plates 8 in the short interval section is increased, the number of flight plates 8 in the long interval section is decreased. The four combination patterns shown in FIG. 4 are different in the combination of sections, but by making the total number of flight plates 8 the same, the amount of sludge scraping can be made the same.

  Since the sludge pit 1a is located below the inflow port 2, the amount of sludge that accumulates at the bottom of the settling basin 1 generally increases as it approaches the sludge pit 1a. If a large amount of sludge accumulates on the flight plate 8 when the scraping operation is stopped, an excessive load may be applied to the drive device 15 or the chain 7 at the start of the scraping operation. In order to prevent such an overload, it is preferable that the long interval section is located near or above the sludge pit 1a when the travel of the flight plate 8 is stopped. That is, it is preferable that the operation control unit 21 stops the driving device 15 when the long interval section is located near or above the sludge pit 1a.

  The sludge scraper includes a flight board detector 24 for detecting the position of the flight board 8. More specifically, the flight plate detector 24 includes a sensor target 25 attached to both ends of the flight plate 8 and a detection sensor 26 that detects the sensor target 25. The sensor target 25 is attached only to some flight plates 8. The detection sensor 26 is disposed in the vicinity of the second driven wheel 5 in the sedimentation basin 1, and is connected to the operation control unit 21 through a signal line 28.

  When the flight board 8 to which the sensor target 25 is attached passes through the vicinity of the detection sensor 26, the detection sensor 26 detects (senses) the sensor target 25 and transmits a detection signal to the operation control unit 21. The operation control unit 21 can detect the relative positions of the short interval section and the long interval section with respect to the bottom of the settling basin 1 based on the detection signal. Therefore, the operation control unit 21 can stop the driving device 15 when a preselected section of the short interval section and the long interval section is located near or above the sludge pit 1a. Furthermore, when the two sensor targets 25 arranged at both ends of one flight board 8 are not detected at the same time, the operation control unit 21 can determine that the flight board 8 is meandering.

  The driven shaft that supports the first driven wheel 4 disposed in the vicinity of the sludge pit 1a is supported by the swing arm 30, whereby the first driven wheel 4 is movable in the vertical direction. FIG. 5 is a front view of the drive wheel 3 and the first driven wheel 4. For simplification of description, the chain 7 is not shown in FIG. As shown in FIG. 5, the two first driven wheels 4 are rotatably supported at both ends of the driven shaft 38, and the driven shaft 38 is connected to the lower ends of the two swing arms 30.

  The drive wheel 3 is fixed to the drive shaft 32. A sprocket 35 that engages with the drive chain 11 (see FIG. 1) is fixed to the end of the drive shaft 32. Two bearings 37 are attached to the drive shaft 32, and the upper end of the swing arm 30 is connected to the outer ring of the bearing 37. Therefore, the swing arm 30 can rotate around the drive shaft 32, and the drive shaft 32 and the first driven wheel 4 supported by the swing arm 30 are movable in the vertical direction. Since the drive shaft 32, the swing arm 30, and the driven shaft 38 can be assembled as one unit, construction is easy. As another embodiment, the upper end of the swing arm 30 may be rotatably connected to an axis other than the drive shaft 32, that is, a support shaft (not shown) parallel to the drive shaft 32.

  FIG. 6 is a view showing a state in which the first driven wheel 4 is moved upward. Since the first driven wheel 4 is supported by the rotatable swing arm 30, if a large amount of sludge accumulates at the bottom of the sedimentation basin 1, the sludge scraping load increases, and the drive wheel 3 and the first driven wheel 4 And the tension applied to the chain 7 extending between the first driven wheel 4 and the second driven wheel 5 increases. Then, since the drive wheel 3, the first driven wheel 4, and the second driven wheel 5 try to be in a straight line, the first driven wheel 4 moves upward by the tension of the chain 7. Then, as shown in FIG. 6, the flight board 8 rakes up the sludge on the bottom of the sedimentation basin 1 toward the sludge pit 1a while riding on the sludge. The first driven wheel 4 moves upward in accordance with the amount of sludge accumulated. Therefore, the load applied to the flight plate 8 when scraping the sludge is reduced, and overloading to the drive unit 15 and the chain 7 is prevented.

  As shown in FIG. 6, when the first driven wheel 4 moves upward, the tension of the chain 7 changes, and the chain 7 may be easily detached from the drive wheel 3 and the first driven wheel 4. Therefore, chain guards 41 and 42 are disposed in the vicinity of the drive wheel 3 and the first driven wheel 4, respectively. The chain guard 41 has an arc surface along the outer periphery of the drive wheel 3, and similarly, the chain guard 42 has an arc surface along the outer periphery of the first driven wheel 4. By disposing these chain guards 41, 42, it is possible to prevent the chain 7 from being detached from the drive wheel 3 and the first driven wheel 4.

  As shown in FIG. 5, the chain guard 42 is connected to the swing arm 30 via a connecting member 46. The chain guard 42 moves up and down integrally with the swing arm 30 and the first driven wheel 4, and the gap between the chain guard 42 and the first driven wheel 4 is constant regardless of the vertical movement of the first driven wheel 4. Kept. Therefore, as shown in FIG. 6, the chain guard 42 prevents the chain 7 from being detached from the first driven wheel 4 even when the flight plate 8 rides up sludge and the first driven wheel 4 rises. Can do.

  FIG. 7 is a schematic view showing another embodiment of the sludge scraper. Since the configuration and operation of the present embodiment that are not particularly described are the same as those of the above-described embodiment, redundant description thereof is omitted. In the embodiment described above, two sets of the first driven wheel 4 and the second driven wheel 5 are provided, whereas in the embodiment shown in FIG. 7, only one set of the driven wheel 5 is provided. The drive wheel 3 and the driven wheel 5 are disposed at the bottom of the sedimentation basin 1. In the present embodiment, the above-described swing arm 30 is not provided.

  In the present embodiment, as in the above-described embodiment, the flight plates 8 are arranged in a short interval section in which the flight plates 8 are arranged at a short interval and in an array longer than the short interval interval. However, it may be composed of other combination patterns shown in FIG.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims.

DESCRIPTION OF SYMBOLS 1 Sedimentation basin 1a Sludge pit 2 Inlet 3 Drive wheel 4 1st driven wheel 5 2nd driven wheel 7 Chain 8 Flight board 11 Drive chain 15 Drive apparatus 19 Water surface guide rail 21 Operation control part 22 Signal line 24 Flight board detector 25 Sensor target 26 Detection sensor 28 Signal line 30 Swing arm 32 Drive shaft 35 Sprocket 37 Bearing 38 Drive shaft 41, 42 Chain guard 46 Connecting member

Claims (9)

A drive wheel and a driven wheel;
A driving device for rotating the driving wheel;
A pair of endless chains supported by the drive wheel and the driven wheel;
A plurality of flight plates attached to the chain;
The plurality of flight plates are arranged at least from a short interval section in which the flight plates are arranged at a short interval and a long interval interval in which the flight plates are arranged at an interval longer than the short interval interval. Sludge scraping machine characterized by.   The sludge scraper according to claim 1, wherein a plurality of the short interval sections and the long interval sections are provided. The driven wheel is composed of a first driven wheel adjacent to a sludge pit formed at the bottom of a sedimentation basin and a second driven wheel arranged farther from the sludge pit than the first driven wheel. ,
The sludge scraper according to claim 1 or 2, wherein the driven shaft that supports the first driven wheel is supported by a swing arm so as to be movable in the vertical direction.   The sludge scraper according to claim 3, wherein the swing arm is rotatably connected to a drive shaft to which the drive wheel is fixed.   The sludge scraper according to claim 3 or 4, further comprising a chain guard having an arc surface along an outer periphery of the first driven wheel.   The sludge scraper according to any one of claims 3 to 5, further comprising a chain guard having an arc surface along an outer periphery of the drive wheel. A sensor target attached to at least one of the plurality of flight plates;
The sludge scraper according to any one of claims 1 to 6, further comprising a detection sensor for detecting the sensor target.   The sludge scraper according to any one of claims 1 to 7, further comprising an operation control unit that intermittently operates the drive device.   The operation control unit stops the driving device when a preselected section of the short interval section and the long interval section is located near or above a sludge pit formed at the bottom of a sedimentation basin. The sludge scraper according to claim 8.

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