JP3988542B2 - Sludge scraper chain breakage detector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chain breakage detection apparatus for a sludge scraper used in a sewage treatment plant or a water purification plant, and more particularly to a chain breakage detection apparatus suitable for a sludge scraper using a plastic chain.
[0002]
[Prior art]
Generally, in sewage treatment plants and water treatment plants, inflow water mixed with sludge is once introduced into a settling tank, and mud and earth contained in the inflow water are precipitated and separated. The precipitated sludge is collected in a sludge pit provided on one side of the bottom of the sedimentation tank by a sludge scraper installed at the bottom of the sedimentation tank, and then discharged out of the precipitation tank.
[0003]
The sludge scraper scrapes sludge by moving a plurality of scraping plates in one direction. In other words, on both side surfaces of the settling tank, circular chains are arranged, and both ends of the scraping plate are attached to two chains, and this chain is driven to drive the scraping plate along the bottom of the settling tank. Slid out and scraped the precipitated sludge and sent it to the sludge pit. The sludge scraped into the sludge pit is periodically discharged by a pump. Further, the scraping plate that has squeezed sludge is guided by a chain that circulates on the side surface and changes its direction upward, and moves backward on the sludge squeezing direction to move on the surface of the sedimentation tank.
[0004]
A component in which such a sludge scraping machine is formed of a plastic material to reduce weight and improve corrosion resistance is known. The scraper plate, chain, and sprocket are made of plastic to reduce the driving force by reducing the weight and to improve the corrosion resistance.
[0005]
[Problems to be solved by the invention]
However, since chains and scraping plates made of plastic are lightweight, buoyancy is generated in water, and they tend to float when moving near the water surface of the settling tank, and easily come off the sprocket. In particular, on the chain exit side where the load on the drive sprocket portion of the chain is small, the chain is easily removed from the winding range of the chain and the sprocket, and tooth skipping is likely to occur. When such tooth skipping occurs, the scraping plate guided by the two-strand chain is inclined with respect to the traveling direction. If the scraper plate is slid in a skewed state, the load applied to the chains arranged on both sides of the scraper plate is not uniform, and eventually the chain is broken. If the chain breaks, it will lead to damage of the device, so it is necessary to detect this early and repair it.
The present invention pays attention to the above problems, and an object of the present invention is to provide a chain breakage detection device for a sludge scraper that can prevent chain skipping and can detect chain breakage.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a chain breakage detecting device for a sludge scraping machine according to the present invention includes a sprocket on the entrance side or the exit side of the circulating chain in a sprocket used to wrap the scraping plate. A chain guide that prevents the tooth of the circulating chain from being pushed by pressing the circulating chain in the center direction of the chain is provided, and the chain guide is attached so as to be movable in the chain pressing direction from the guide position when the chain is broken. The chain breakage is detected by detecting the position movement of the chain guide .
[0007]
In addition, a chain guide that presses the rotating chain toward the center of the sprocket at the entrance side or the exit side of the rotating chain in the sprocket used to wrap the scraper plate, and the side surface of the chain is elastically biased The urging means may be provided so that the position of the urging means is displaced when the chain is broken, and the breakage of the chain is detected by detecting the displacement of the urging means .
In addition, when attaching a scraping board to a chain, it is very effective when installing a tooth skip prevention chain guide if it is set as the structure connected via a connection material.
[0008]
[Action]
With the above configuration, when the chain is broken, the position of the chain guide or biasing means for preventing tooth skipping is displaced, and the chain breakage can be detected by detecting this position change.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a specific embodiment of a chain breakage detection apparatus for a sludge scraper according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing the arrangement of a sludge scraper in a sedimentation tank, FIG. 2 is an explanatory view of an engaged state of a sprocket and a chain according to the present invention, and FIG. 3 is an explanatory view of a chain breaking device according to the present embodiment. (1) is a perspective view and (2) is a front view.
[0010]
In water treatment facilities such as a sewage treatment plant and a water purification plant, sewage is introduced into the sedimentation tank 1 where it is separated into sludge and water. Sludge contained in the sewage settles to the bottom of the sedimentation tank 1 and is accumulated in the sludge pit 3 by the sludge scraper 2 disposed inside the sedimentation tank 1.
[0011]
As shown in FIG. 1, the sludge scraper 2 is provided with a circulating chain 4 on both side surfaces of the settling tank 1 facing each other, and a plurality of scraping plates 5 are bridged to the two circulating chains 4. . A driving force is applied to the circulating chain 4 via a sprocket 6. The circulating chain 4 moves the bottom of the sedimentation tank 1 in the direction toward the sludge pit 3, then changes the direction upward, and moves near the water surface of the sedimentation tank 1 in the direction opposite to the traveling direction of the bottom of the sedimentation tank 1. Go around. Accordingly, the scraping plate 5 slides and moves on the bottom of the sedimentation tank 1 to scrape the sludge at the bottom and accumulate it in the sludge pit 3, and then is guided by the circulation chain 4 and circulates upward. The scum generated near the surface of the water is raked up and returned to the bottom again.
[0012]
As shown in FIG. 2, the sprocket 6 is arranged in parallel so that two disks 10 face each other, and the centers of these disks 10 are connected by a boss 7 serving as a central axis. A plurality of mounting holes 12 are provided on the outer periphery of the disk 10 at an equal pitch, and feed pins 14 are spanned and attached to the mounting holes 12. That is, the portion corresponding to the teeth of the sprocket 6 is formed by the feed pin 14. Such sprockets 6 are provided at four places on the front and rear and upper and lower sides of the sedimentation tank 1, and one set is arranged on each of the left and right side surfaces as a set, and is provided at a total of eight places. Among the sprockets around which the single rotating chain 4 is wound, one sprocket 6A is a drive sprocket. A drive shaft 8 is inserted into the central axis of the sprocket 6A and a rotational force is applied by a motor 9.
[0013]
The mounting holes 12 of the sprocket 6 are formed by drilling a set of spare mounting holes 12A and 12B on the outer periphery of the disk 10, so that when the mounting hole 12 is broken by a load applied to the feed pin 14, the feed pin 12 The disk 10 can be used again by changing the mounting position of 14. In the present embodiment, such a sprocket 6 is formed of a plastic material. Thereby, it is possible to provide the sprocket 6 which is lighter than steel and has excellent corrosion resistance.
[0014]
The circulating chain 4 has a configuration in which a plurality of segments 18 are connected endlessly. The segment 18 has a substantially L-shaped engagement step portion 16 that engages with the feed pin 14 of the sprocket 6, and connecting portions 19 that pin-connect the segments are provided at both ends in the longitudinal direction. ing. The height of the engagement step portion 16 is approximately the same as the outer radius of the feed pin 14. The engaging step portion 16 is formed over the entire width of the segment 18, and at this time, the width of the segment 18 is formed to be approximately the same as or slightly shorter than the length of the feed pin 14. The length of the segments 18 in the longitudinal direction is such that the mutual distance of the engaging step portions 16 becomes equal to the pitch interval of the feed pins 14 of the sprocket 6 when the segments 18 are connected to each other. Such a segment 18 is formed of a plastic material.
[0015]
A plurality of scraping plates 5 that scrape the sludge in the sedimentation tank 1 are attached to the circulating chain 4 at equal intervals. The scraping plate 5 is made of a plastic material and has a substantially U-shaped cross section having a length substantially equal to the transverse cross section of the bottom of the sedimentation tank 1. As shown in FIG. 3 (2), the scraping plate 5 is attached to the circulating chain 4 via a connecting member 20. As the connecting member 20, a prism having a side length of about ３ of the chain width is used. Thus, by attaching the connecting member 20 between the circulating chain 4 and the scraping plate 5, a gap is created between them, and this gap can be utilized when installing a chain guide described later. It becomes. Note that a cylinder may be used as the connecting member 20.
[0016]
By the way, the above-described circling chain 4, sprocket 6 and scraper plate 5 are made of plastic material, and thus are lightweight and excellent in corrosion resistance. However, when these members are arranged in water, buoyancy is generated. It becomes easy to float. In particular, in the drive sprocket 6A that is arranged above the settling tank 1 and changes the direction of the circulating chain 4 that rises in the vertical direction in the horizontal direction, the load applied to the chain 4 is suddenly increased on the exit side on which the circulating chain 4 is wound. In order to reduce this, it is conceivable that the rotating chain 4 is lifted from the winding range of the sprocket 6A, the engagement between the rotating chain 4 and the sprocket 6A is released, and tooth skipping occurs. Therefore, in the present embodiment, the chain breakage detection device 22 that prevents tooth spattering of the circulating chain 4 with respect to the sprocket 6A provided in the upper part of the settling tank 1 and can detect when the circulating chain 4 is broken. Is provided. The chain breakage detection device 22 is attached to the outlet side (upper part) of the sprocket 6A on the upper side of the sedimentation tank 1 where the engagement of the circulating chain 4 is easily released by buoyancy as described above.
[0017]
The chain breakage detecting device 22 presses the rotating chain 4 in the center direction of the sprocket 6 (in this case, from top to bottom) so that the rotating chain 4 is in close contact with and engaged with the winding range of the sprocket 6. The chain guide 24 for preventing the rotation and the detecting means for detecting the breakage of the circulating chain 4 are configured.
[0018]
The chain guide 24 is provided with rollers 32 that can be brought into rolling contact with both side portions of the rotating chain 4 and elastically biasing the rollers 32 with a spring to press the rotating chain 4 toward the sprocket 6. .
[0019]
Specifically, the cylindrical rollers 32 are arranged so as to be in line contact with the left and right ends of the circumferential chain 4 in the width direction. The roller 32 is formed to have a small diameter so as not to obstruct the movement of the scraping plate 5 on the chain 4 side, and can be inserted into the gap between the circulating chain 4 and the scraping plate 5. Further, the length of the roller 32 is set such that the roller 32 can be in line contact with the circulating chain 4 without interfering with the connecting member 20. The roller 32 is attached to the post 34 in a cantilever state so as to be freely rotatable via a bearing (not shown).
[0020]
The post 34 is formed in a column shape and has a height at least equal to or greater than the thickness of the circular chain 4. The posts 34 to which the left and right rollers 32 are respectively attached are attached to a single support plate 36 disposed in parallel with the back surface of the circular chain 4. Further, a guide member 38 having a T-shaped cross section is provided on the bottom surface of the support plate 36 so as to move in a direction perpendicular to the surface of the circular chain 4. The guide member 38 is for restricting the movement of the roller 32 so that the roller 32 is maintained in parallel with the circular chain 4 and properly contacts the chain 4.
[0021]
A guide support frame 40 is provided outside the chain guide 24. The guide support frame 40 is configured to accommodate the support plate 36 therein, and the two side plates 42 are arranged on the bottom plate 44 so that the L-shaped convex portions of the side plate 42 formed in an approximately L shape are on the upper side and the inner surfaces are opposed to each other. And the support plate 36 is disposed inside the side plates 42. That is, the upper L-shaped convex surface of the side plate 42 and the support plate 36 are arranged in parallel. A through hole 45 is formed in the bottom plate 44 so that the guide member 38 can reciprocate in the vertical direction, and the guide member 38 is inserted into the through hole 45. As a result, the chain guide 24 can move in the vertical direction inside the guide support frame 40.
[0022]
A spring 28 is provided to urge the chain guide 24 downward from above, and a force in the opposite direction to the force that the circulating chain 4 tries to separate from the sprocket 6 is generated. The spring 28 is a compression coil spring and is disposed between the inner surface of the L-shaped convex portion of the side plate 42 and the support plate 36 of the chain guide 24. As a result, a force that urges the entire chain guide 24 downward is generated, and the rotating chain 4 can be pressed against and closely contacted with the sprocket 6 by the roller 32.
[0023]
In the present embodiment, the support plate 36 is elastically biased downward using a compression spring. However, the lower portion of the support plate 36 and the upper surface of the bottom plate 44 of the guide support frame 40 are connected by a tension spring to lower the support plate 36. A biasing force may be applied in the direction. It is also possible to adopt a configuration in which the rotating chain 4 is pressed by an actuator other than a spring.
[0024]
The chain guide 24 detects this when the circulating chain 4 is broken. As shown in FIG. 4 (2), a proximity sensor 50 is provided as a detecting means at the lower part of the side plate 42 in the guide support frame 40 of the chain guide 24. A detection plate 52 is provided on the side of the support plate 36 so as to correspond to the proximity sensor 50. When there is an object within the range of the sensor, the proximity sensor 50 transmits a signal to a control unit (not shown). The control unit is provided with a mechanism for notifying that there is an object in the vicinity of the proximity sensor 50, for example, sounding an alarm or turning on a warning light.
[0025]
FIG. 4A shows a case where the rotating chain 4 is broken within the winding range of the sprocket 6. In the normal state, tension is generated in the rotating chain 4, and the chain guide 24 elastically biases the rotating chain 4 toward the sprocket 6 against this. At this time, when the circulating chain 4 is broken, the broken end portion of the circulating chain 4 comes out of the lower region of the roller 32, and the chain guide 24 becomes free. As a result, the chain guide 24 falls to the bottom of the guide support frame 40. Due to this position change, the detection plate 52 approaches the proximity sensor 50, and the proximity sensor 50 detects this and sends a signal to the control unit.
[0026]
At this time, the control unit is provided with a program for controlling the driving of the sprocket 6 of the sludge scraper 2 and automatically stops the driving of the sprocket 6 when the proximity sensor 50 detects that the circulating chain 4 is broken. A configuration is preferable. As a result, when the circulating chain 4 breaks, the sludge scraper 2 can be stopped immediately, and a load is applied to the broken circulating chain 4, the other circulating chain 4, or individual sprockets 6. It is possible to prevent further damage from spreading.
[0027]
Thus, the chain breakage detection device 22 of the sludge scraper 2 according to the present embodiment can press the rotating chain 4 with the chain guide 24 and prevent tooth skipping. Further, the change of the position of the chain guide 24 when the circulating chain 4 is broken is detected, and the breaking of the circulating chain 4 is detected. Therefore, tooth skip prevention and break detection can be realized in one configuration.
[0028]
FIG. 5 is a cross-sectional view of an essential part showing another embodiment of the present invention. In FIG. 5, the roller 62 protruding from the box-shaped support body 60 restricts the lifting of the rotating chain 4 in the same manner as in the above-described embodiment, and prevents tooth skipping of the rotating chain at the sprocket portion. Further, a roller 64 that contacts the side surface of the circulating chain 4 is disposed, and an urging means by a spring 68 that presses the roller 64 in the horizontal direction via the arm 66 is provided. A detection plate 70 is provided on the spring 68 side of the arm 66 having a T-shaped cross section. Further, when the spring 68 is extended, a proximity sensor 72 is provided at a position where the detection plate 70 has moved, and this signal is sent to the control unit. As a result, when the circular chain 4 is broken and deviates from the suppression range of the detection device, the arm 66 is pushed in the horizontal direction by the spring 68, and the detection plate 70 approaches the proximity sensor 72. By notifying the operator of this state with an alarm or the like by the control unit, it is possible to determine that the circulating chain 4 is broken.
[0029]
In each of the above-described embodiments, the proximity sensor is used as a means for detecting the position change of the chain guide 24 or the urging means. However, the present invention is not limited to this, and other means can be used. For example, an appropriate means such as a pressure sensor for detecting a change in elastic force of a spring or a position sensor for measuring a distance displacement of an object can be selected.
[0030]
【The invention's effect】
According to the present invention, the chain guide can prevent the chain from jumping at the sprocket portion. Further, when the chain is broken, the breakage of the chain can be quickly detected by detecting the change in the position of the chain guide itself or the change in the position of the biasing means that elastically biases the side surface of the chain.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the arrangement of a sludge scraper and a chain breakage detection device in a sludge settling tank.
FIG. 2 is an explanatory diagram of an engaged state of a sprocket and a chain according to the present invention.
FIGS. 3A and 3B are explanatory diagrams of a chain breakage detecting device according to the present embodiment, wherein FIG. 3A is a perspective view and FIG. 3B is a front view.
FIG. 4 is an explanatory diagram of chain breakage detection.
FIG. 5 is a cross-sectional view of a main part in a modification of the chain breakage detection device according to the present invention.
[Explanation of symbols]
1 ......... Sedimentation tank, 2 ......... Sludge scraping machine, 3 ......... Sludge pit, 4 ......... Surrounding chain, 5 ......... Scraping plate, 6 ...... Sprocket, 7 ...... Boss, 8 ......... Drive shaft, 9 ......... Motor, 10 ......... Disk, 12 ......... Mounting hole, 14 ......... Feed pin, 16 ......... engaging step, 18 ......... Segment, 19 ... ...... Connecting part, 20 ...... Connecting material, 22 ...... Chain break detection device, 24 ...... Chain guide, 28, 68 ...... Spring, 32, 62, 64 ...... Roller, 34 ...... Post, 36 ......... Support plate, 38 ......... Guide material, 40 ... …… Guide support frame, 42 ......... Side plate, 44 ......... Bottom plate, 45 ......... Through hole, 50, 72 ......... Proximity Sensor, 52, 70 ... Detection plate, 60 ... Support, 66 ... Arm.

Claims (2)

A chain guide for preventing tooth skipping of the rotating chain by pressing the rotating chain toward the center of the sprocket at the entrance side or the exit side of the rotating chain in the sprocket for winding the chain used for rotating the scraping plate The chain guide is attached so as to be movable in the direction of pressing the chain from the guide position when the chain is broken, and the breakage of the chain is detected by detecting the position movement of the chain guide. Sludge scraper chain breakage detector. A chain guide that presses the rotating chain toward the center of the sprocket at the entrance side or the exit side of the rotating chain in the sprocket that wraps the chain used for circling the scraping plate, and a bias that biases the side surface of the chain. The sludge scraper is provided with a biasing means, wherein the position of the biasing means is displaced when the chain is broken, and the breaking of the chain is detected by detecting the displacement of the biasing means. Chain break detection device for machinery.

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