JP6734599B1 - Sludge scraper and endless chain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sludge scraper and an endless chain having sufficient strength and resistant to corrosion. A sludge scraper for running a long flight body in a direction perpendicular to its longitudinal direction to scrape up sludge accumulated on the bottom of a sedimentation pond, wherein a plurality of the flight bodies are provided. By circulating and driving a pair of endless chains in which a plurality of chain links fixed at predetermined intervals are pivotally attached by a connecting shaft and endlessly connected, and the endless chain that is disposed in the sedimentation tank and stretched It is provided with a main sprocket wheel and a driven sprocket wheel for scraping sludge settled on the pond bottom by the flight body, and the chain link and the connecting shaft in the endless chain are made of PC (polycarbonate). Sludge scraper. [Selection diagram] Figure 1

Description

The present invention relates to a sludge scraper and an endless chain, and particularly to a sludge scraper that runs a long flight body in a direction perpendicular to the longitudinal direction thereof and scrapes sludge accumulated on the bottom of a sedimentation pond. And endless chains.

At sewage treatment plants, sewage sewage is purified and discharged to rivers, lakes or the sea. Sewage that has entered the sewage treatment plant is first sent to the settling tank by a pump after the dust is removed by the screen. Here, the difference in specific gravity is mainly used to remove the dirt that tends to settle in the drinking water due to gravity settling. Next, the sewage is sent to the biological reaction tank, the returned sludge is added, and the high-concentration microorganisms adsorb, ingest, and digest the organic matter. The sewage is then sent to the final settling basin. In this final settling tank, the activated sludge is slowly settled and the supernatant is discharged into a river, lake or sea, and the activated sludge in the final settling tank is pumped to the biological reaction tank for reuse.

In the final sedimentation tank, the sludge scraping machine scrapes up the sludge accumulated on the bottom of the final sedimentation tank and collects it in the mud collecting pit. Here, since the sewage contains corrosive components, the sludge settled on the bottom of the final settling tank has condensed corrosive components. For this reason, the sludge scraper has been conventionally provided with measures against corrosion.

For example, in a conventional sludge scraper, constituent members are made of stainless steel in order to prevent corrosion. However, even if the sludge scraper is made of stainless steel, if the sludge in which the corrosive components are condensed is clogged inside the flight body and is rotted over time, the flight body may be corroded from the inner surface.

Therefore, in the invention disclosed in Patent Document 1, in a flight body formed of stainless steel and having a hollow portion inside, an opening communicating with the hollow portion inside may be formed on any surface of the flight body. Proposed. Further, it is disclosed that this opening is preferably provided on the back side of the scratch, and more preferably on both the back side and both end surfaces.

JP 2004-283786 A

However, in the invention disclosed in Patent Document 1, although the scraper itself is made of stainless steel, the stainless steel may be corroded due to deterioration over time. Therefore, in order to prevent corrosion, there is a sludge scraper made of resin.

However, sludge treated with sewage contains hydrogen sulfide and is highly corrosive. Therefore, when the constituent members of the sludge scraper are made of resin, POM (polyacetal or polyoxymethylene) is often used to prevent corrosion due to the strong acidity of hydrogen sulfide. However, POM has excellent acid resistance, but contains formaldehyde, and this formaldehyde elutes, so that it cannot be used for treating tap water.

Further, when the constituent member of the sludge scraper is POM, nylon is used as a constituent member of the connecting shaft (pin) that connects the chain links forming the endless chain because of the slidability problem. However, since the nylon coupling shaft (pin) has a water absorption rate of about 3%, in a sludge scraper used in water, the nylon pin swells and the chain link moves poorly (splashes). In addition, since the water temperature has been rising in recent years, there is concern about the elongation of the endless chain, but since POM and nylon have a high coefficient of thermal expansion, the endless chain may fall off the sprocket wheel.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a sludge scraper and an endless chain that have sufficient strength and are resistant to corrosion.

In order to solve the above problems, the sludge scraper according to the present invention runs a long flight body in a direction perpendicular to its longitudinal direction to scrape sludge accumulated on the bottom of a sedimentation pond. A sludge scraper, wherein the plurality of flight bodies are arranged in the sedimentation basin, and a pair of endless chains in which a plurality of chain links fixed at predetermined intervals are pivotally attached by a connecting shaft and endlessly connected, It comprises a main sprocket wheel and a driven sprocket wheel for scraping sludge deposited on the pond bottom by the flight body by circulatingly driving the stretched endless chain, and the chain link and the connecting shaft in the endless chain are It is characterized by being composed of PC (polycarbonate).

As described above, in the sludge scraper according to the present invention, the chain link and the connecting shaft of the endless chain are formed of PC. Since PC does not emit harmful substances (eg formaldehyde), it can be used not only in sewage treatment but also in water treatment. Further, the tensile strength of PC is higher than that of POM (polyacetal or polyoxymethylene), and the chain elongation due to deterioration over time is small. Furthermore, by using PC, it is possible to provide a sludge scraper that is more resistant to corrosion than stainless steel and is inexpensive. Further, since the PC is easier to reuse than the POM, the resources can be effectively used. If the PC is not colored or is colored to the extent that it has a light-transmitting property (to the extent that the internal state can be understood), the chain links and the connecting shaft have a light-transmitting property, so internal bubbles that are likely to occur during molding with the PC The state of can be accurately grasped visually. Further, since the component of the connecting shaft that connects the chain links is PC instead of nylon, it is possible to reduce the possibility that the connecting shaft swells like nylon and the chain links move poorly (splash). Further, since the coefficient of thermal expansion is lower than that of POM or nylon, it is possible to reduce the risk that the endless chain will be detached from the sprocket wheel.

Further, the sludge scraper according to the present invention is characterized in that it further comprises a pin hook for retaining attached to one end side of the connecting shaft inserted into the chain link, and the pin hook is composed of a PC. Further, the pin hook is provided with a hollow hole. As described above, in the sludge scraper according to the present invention, since the pin hooks for preventing the connecting shaft from coming off are made of PC, the tensile strength is higher than POM, the durability due to aging deterioration is higher, and the corrosion is higher than stainless steel. It is possible to provide a sludge scraper that is strong and inexpensive. Further, since the pin hook is provided with the hollow hole, it is possible to prevent air bubbles from being mixed in during molding by the PC.

Further, in the sludge scraper according to the present invention, among the plurality of connecting shafts connecting the plurality of chain links, the adjacent connecting shafts are inserted in alternate directions. Since the adjacent connecting shafts in the sludge scraper according to the present invention are inserted in alternate directions as described above, the imbalance in the elongation of the endless chain based on the asymmetry of the shape of the connecting shafts is suppressed, and the endless chain is prevented. It is easy to keep the straightness of the chain in the traveling direction.

In addition, the plurality of chain links of the sludge scraper according to the present invention respectively include a cylindrical base having a first through hole (boss) for inserting the connecting shaft, and a longitudinal direction from both ends of the base. A pair of plate portions that extend symmetrically in the vertical direction with respect to each other, and the plate portions each have a second through hole (boss) for inserting a connecting shaft on the side opposite to the base portion, The first rib portion is provided so as to surround the periphery of the second through hole, and the plate portion has a first rib portion that is erected in a direction perpendicular to an outer main surface opposite to an inner main surface facing each other. To do.

As described above, the pair of plate portions forming each chain link of the sludge scraper according to the present invention has the second through hole (boss) for inserting the connecting shaft on the side opposite to the base portion. The first rib portion is provided so as to surround the periphery of the second through hole and is raised in a direction perpendicular to the outer main surface opposite to the inner main surface where the plate portions face each other. In this chain link, the first rib portion that bulges in the vertical direction with respect to the outer main surface opposite to the inner main surface where the plate portions face each other around the second through hole into which the connecting shaft to which force is applied is inserted. Since each of the members is provided, sufficient strength can be obtained even if each member is made of a synthetic resin material.

In addition, the pair of plate portions of the plurality of chain links of the sludge scraper according to the present invention respectively bulge in a direction perpendicular to the outer main surface, and the second through holes extend from the first through holes. It is characterized in that it has a second rib portion extending to the hole.

As described above, each of the pair of plate portions of the plurality of chain links of the sludge scraper according to the present invention is raised in the direction perpendicular to the outer main surface and extends from the first through hole to the second through hole. Since it has the existing second rib portion, the strength can be further increased.

Further, in the sludge scraper according to the present invention, the second rib portion is provided in a substantially Y-shape that is branched midway from the first through hole toward the second through hole. And In this way, the second rib portion is provided in a substantially Y shape, so that the reinforcing effect on the side of the second through hole which is open between the pair of plate portions can be further enhanced.

The endless chain according to the present invention is an endless chain used in a sludge scraping machine that runs a long flight body in a direction perpendicular to the longitudinal direction thereof and scrapes sludge accumulated on the bottom of a sedimentation pond. The plurality of flight bodies are endlessly connected by pivotally attaching a plurality of chain links fixed at predetermined intervals by connecting shafts, and the chain links and the connecting shafts are made of PC (polycarbonate). It is characterized by that.

As described above, in the endless chain according to the present invention, since the chain link and the connecting shaft are made of PC, they do not emit harmful substances (eg formaldehyde) and are used not only in sewage treatment but also in water treatment. be able to. Further, the tensile strength of PC is higher than that of POM, and the chain elongation due to deterioration over time is small. Furthermore, by using PC, it is possible to provide a sludge scraper that is more resistant to corrosion than stainless steel and is inexpensive. Further, since the PC is easier to reuse than the POM, the resources can be effectively used. When the PC is not colored or is colored to the extent that it has a light-transmitting property (to the extent that the internal state can be seen), the chain links and the connecting shaft have a light-transmitting property, and therefore air bubbles inside the PC when molded The state of can be accurately grasped visually. Further, since the component of the connecting shaft that connects the chain links is PC instead of nylon, it is possible to reduce the possibility that the connecting shaft swells like nylon and the chain links move poorly (splash). Further, since the coefficient of thermal expansion is lower than that of POM or nylon, it is possible to reduce the risk that the endless chain will be detached from the sprocket wheel.

In addition, the endless chain according to the present invention is characterized in that the endless chain further includes a pin hook for retaining attached to one end side of the connecting shaft inserted into the chain link, and the pin hook is configured by a PC. Further, the pin hook is provided with a hollow hole. As described above, in the endless chain according to the present invention, since the pin hook for preventing the connecting shaft from coming off is made of PC, it has higher tensile strength than POM, higher durability due to aged deterioration, and more corrosion resistance than stainless steel. It is possible to provide a strong and inexpensive endless chain. Further, since the pin hook is provided with the hollow hole, it is possible to prevent air bubbles from being mixed in during molding by the PC.

Further, in the endless chain according to the present invention, among the plurality of connecting shafts that connect the plurality of chain links, the adjacent connecting shafts are inserted in alternate directions. Since the adjacent connecting shafts of the endless chain according to the present invention are inserted in alternate directions as described above, unbalance in the elongation of the endless chain due to the asymmetry of the shape of the connecting shaft is suppressed, and the endless chain. It becomes easier to maintain straightness in the traveling direction of.

In addition, the plurality of chain links of the endless chain according to the present invention respectively include a cylindrical base having a first through hole (boss) for inserting the connecting shaft, and a longitudinal direction from both ends of the base. On the other hand, a pair of plate portions extending symmetrically in the vertical direction are provided, and the plate portions each have a second through hole (boss) for inserting a connecting shaft on a side opposite to the base portion, and The first rib portion is provided so as to surround the periphery of the second through hole, and the plate portions have a ridge protruding in a direction perpendicular to an outer main surface opposite to the inner main surface facing each other. ..

As described above, the pair of plate portions constituting each chain link of the endless chain according to the present invention has the second through hole (boss) for inserting the connecting shaft on the side opposite to the base portion. The first rib portions are provided so as to surround the periphery of the two through holes, and the plate portions are respectively raised in the vertical direction with respect to the inner main surface facing each other and the outer main surface on the opposite side. In this chain link, the first rib portion that bulges in the vertical direction with respect to the outer main surface opposite to the inner main surface where the plate portions face each other around the second through hole into which the connecting shaft to which force is applied is inserted. Since each of the members is provided, sufficient strength can be obtained even if each member is made of a synthetic resin material.

In addition, the pair of plate portions of the plurality of chain links of the endless chain according to the present invention respectively bulge in a direction perpendicular to the outer main surface, and extend from the first through hole to the second through hole. It is characterized in that it has a second rib portion extending to the end.

As described above, the pair of plate portions of the plurality of chain links of the endless chain according to the present invention each bulge in the direction perpendicular to the outer main surface and extend from the first through hole to the second through hole. Since it has the 2nd rib part which acts, strength can be raised further.

Further, in the endless chain according to the present invention, the second rib portion is provided in a substantially Y-shape that is branched midway from the first through hole toward the second through hole. To do. In this way, the second rib portion is provided in a substantially Y shape, so that the reinforcing effect on the side of the second through hole which is open between the pair of plate portions can be further enhanced.

As described above, according to the present invention, it is possible to provide a sludge scraper and an endless chain that have sufficient strength and are resistant to corrosion.

It is sectional drawing of a sedimentation tank and a sludge scraper. It is a top view of a sprocket wheel. It is a block diagram of the chain link which comprises an endless chain. It is an exploded perspective view in a part of endless chain. It is a figure which shows the meshing of a sprocket wheel and an endless chain. It is sectional drawing of a support member. It is a figure which shows the engagement of the sprocket wheel and endless chain in other embodiment.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a vertical cross section of a sedimentation tank A in a sewage plant. In the settling basin A, the sludge scraper 1 according to the embodiment is installed.

As shown in FIG. 1, the sludge scraper 1 includes a flight body 100, an endless chain 200, a main sprocket wheel 300, a driven sprocket wheel 400, and a driving means 500. The main sprocket wheel 300 and a plurality of driven sprocket wheels 400 are installed on the left and right walls of the settling basin A, and the main sprocket wheel 300 is provided with a motor 520 for driving and rotating the main sprocket wheel 300. The device (driving means) 500 is connected via a power transmission belt 510.

Here, the main sprocket wheel 300 is supported on the wall surface of the sedimentation basin A by the support member 600 near the water surface WL at the longitudinal end of the sedimentation basin A, and one driven sprocket wheel 400 is substantially the same as the sedimentation basin A in the longitudinal direction. The other driven sprocket wheels 400 are supported near the water surface WL in the center, and are supported on the wall surface of the sedimentation tank A by the support members 600 near the bottom BT on both longitudinal ends of the sedimentation tank A.

The endless chain 200 is composed of a main sprocket wheel 300 provided on the left and right walls of the sedimentation tank A and a pair of left and right endless chains 200 rotatably stretched around a plurality of driven sprocket wheels 400, and a plurality of chain links 210. (See FIG. 3) is pivotally attached by a connecting shaft and is endlessly connected.

Between the pair of left and right endless chains 200 provided along each of the left side wall and the right side wall of the settling basin A, a long flight body 100 is suspended and fixed at predetermined intervals, By rotating the main sprocket wheel 300 and circulatingly driving the endless chain 200 in the settling tank A in the clockwise direction (CW) as shown in FIG. 1, sludge settling on the bottom of the pond is sludged in the sludge pit (discharge groove) by the flight body 100. )15.

Here, the chain link 210 (see FIG. 3) and the connecting shaft 240 (see FIG. 4) in the endless chain 200 of the sludge scraper 1 of the present embodiment are made of PC (polycarbonate).

Further, each member of the main sprocket wheel 300 and the driven sprocket wheel 400 of the sludge scraper 1 of the present embodiment is a synthetic resin material selected from PET (polyethylene terephthalate), PEN (polyethylene naphthalate) or PC (polycarbonate). Preferably. Further, PET or PEN, which is a synthetic resin forming each member of the main sprocket wheel 300 and the driven sprocket wheel 400 of the sludge scraper 1 according to the present embodiment, is transparent or translucent in an uncolored state, that is, It is preferably not crystallized.

(Sprocket wheel)
FIG. 2 is a plan view of the main sprocket wheel 300. Hereinafter, the configuration of the main sprocket wheel 300 will be described with reference to FIG. As shown in FIG. 2, the main sprocket wheel 300 is a disk-shaped member made of a synthetic resin material selected from PET, PEN, or PC, and has a through hole 301 in the center for passing a shaft (main shaft).

The main sprocket wheel 300 has a tooth portion 302 formed on the circumference with a predetermined width. When the tooth portion 302 meshes with the endless chain 200, the main sprocket wheel 300 can be rotated to drive the endless chain 200 in a circulating manner. Further, in the main sprocket wheel 300, from the viewpoint of ensuring strength, a rib portion 303 that is raised so as to surround the through hole 301 and from the rib portion 303 toward the outer peripheral side (tooth portion 302) of the main sprocket wheel 300. A plurality of rib portions 304 extending in the vertical direction and a plurality of hollow holes 305H provided between the rib portions 304 are provided. The configuration of the driven sprocket wheel 400 is the same as the configuration of the main sprocket wheel 300, and a duplicate description will be omitted.

(Endless chain)
FIG. 3 is a configuration diagram of a chain link that constitutes an endless chain. FIG. 3A shows a top view of the chain link 210 that constitutes the endless chain 200. FIG. 3B shows a side view of the chain link 210 that constitutes the endless chain 200.
FIG. 4 is an exploded perspective view of a part of the endless chain. Note that FIG. 4 shows an exploded perspective view of the four chain links 210 of the endless chain 200.
Hereinafter, the configuration of the endless chain 200 will be described with reference to FIGS. 3 and 4. As shown in FIG. 4, the endless chain 200 is configured by connecting a plurality of chain links 210. Each chain link 210 is made of PC, and has a cylindrical base portion 211 having a first through hole 210H (boss) for inserting the connecting shaft 240, and both ends 211A and 211B of the base portion 211 in a direction perpendicular to the longitudinal direction. A pair of plate parts 220 and 230 extending symmetrically are provided.

The plate portions 220 and 230 include second through holes (bosses) 220H and 230H for inserting the connecting shaft 240 (see FIG. 4) on the side opposite to the base portion 211 and second through holes 220H and 230H. The plate portions 220 and 230 have first rib portions 220D and 230D that bulge in a direction perpendicular to the inner main surfaces 220A and 230A facing each other and the outer main surfaces 220B and 230B on the opposite side so as to surround the periphery. .. In addition, the pair of plate portions 220 and 230 respectively bulge in a direction perpendicular to the outer main surfaces 220B and 230B and extend from the first through hole 210H to the second through holes 220H and 230H. It has ribs 220E and 230E. Then, the second through holes 220H and 230H of the chain link 210 on the upper side with respect to the rotation direction of the endless chain 200 and the first through hole 210H of the chain link 210 on the lower side are connected to the connecting shaft 240 (see FIG. 4). ), the endless chain 200 can be obtained by connecting it endlessly.

Here, from the first through hole 210H (boss) provided in the base 211 to the second through holes (boss) 220H, 230H for inserting the connecting shaft 240 provided on the side opposite to the base 211. The straight line distance L1 is about 152.4 mm. Further, in order to secure the strength of the chain link 210, the thickness D1 of the front end portion T1 of the pair of plate portions 220 and 230 is preferably 7 mm or more, and the thickness D2 of the rear end portion T2 is 5 mm or more. It is preferable.

In addition, each of the second rib portions 220E and 230E is provided in a substantially Y shape that is branched midway from the first through hole 210H to the second through holes 220H and 230H. That is, each of the second rib portions 220E and 230E includes one central portion 231 extending from the central portion of the plate portions 220 and 230 to the first through hole 210H side and the central portion 231 to the second penetrating portion. It has a branch portion 232 that is divided into two parts toward the holes 220H and 230H, expands at a predetermined angle, and extends to the first rib parts 220D and 230D.

On the other hand, the closed first through-hole 210H side between the pair of plate portions 220 and 230 is reinforced by the single central portion 231, so that the material can be suppressed. The height of each protrusion of the second rib portions 220E and 230E may be gradually increased from the first through hole 210H to the second through holes 220H and 230H. As a result, the width of the chain link 210 is not unnecessarily expanded by the second rib portions 220E and 230E.

Further, a plurality of rib portions 235 may be radially provided around the first rib portions 220D and 230D. In the example shown in FIG. 4, three rib portions 235 are provided around each of the first rib portions 220D and 230D. Thereby, the strength around each of the first rib portions 220D and 230D in the plate portions 220 and 230 can be further increased.

The plate portions 220 and 230 are respectively raised in the vertical direction with respect to the inner main surfaces 220A and 230A facing each other so as to surround the second through holes 220H and 230H of the pair of plate portions 220 and 230. You may make it provide a 3rd rib part. In this case, the thickness of the third rib portion is preferably in the range of 0.5 mm to 1.5 mm. Further, it is preferable that the third rib portion has a trapezoidal cross-sectional shape, and the uppermost surface of the trapezoid is a flat surface having a predetermined width.

As shown in FIG. 4, the endless chain 200 is formed by endlessly connecting a plurality of chain links 210 by a connecting shaft 240. A fixing member 270 for mounting the flight body 100 is provided on any one of the plurality of chain links 210.

In the endless chain 200, the base portion 211 side of one chain link 210 of two adjacent chain links 210 is inserted between the plate portions 220 and 230 on the opposite side of the base portion 211 of the other chain link 210. Then, in a state where the first through hole 210H and the second through hole 230H of both chain links 210 are aligned, the connecting shaft 240 is inserted so as to penetrate the first through hole 210H and the second through hole 230H. The two chain links 210 are connected by.

A head 241 having a larger diameter than the shaft portion is provided at the end of the connecting shaft 240. Therefore, by inserting from the tip of the connecting shaft 240 (on the side opposite to the head 241) into the first through hole 210H and the second through hole 230H, the head 241 can be inserted to a position where it hits the chain link 210. .. A flat portion 2411 is provided on a part of the outer periphery of the head portion 241, and by being aligned with the convex portion 2301 provided on the first rib portion 230D, rotation of the inserted connecting shaft 240 is prevented. It

A notch 243 is provided on the tip side of the connecting shaft 240. The cutout portions 243 are provided on both sides of the shaft portion. Accordingly, in the state where the connecting shaft 240 is inserted into the first through hole 210H and the second through hole 230H, the notch at the tip of the connecting shaft 240 that has penetrated from the first through hole 210H and the second through hole 230H. A pin hook 250 for retaining can be fitted into the portion 243. The pin hook 250 is a substantially C-shaped clip member. By fitting the pin hook 250 in the position of the cutout portion 243, the effect of preventing the fitted pin hook 250 from falling off is enhanced.

In the endless chain 200 according to the present embodiment, it is preferable that the pin hook 250 is made of PC. Further, the pin hook 250 is preferably provided with a hollow hole 250H. In the example shown in FIG. 4, one pin hook 250 is provided with three hollow holes 250H.

Further, in the endless chain 200 according to the present embodiment, in the plurality of connecting shafts 240 that connect the plurality of chain links 210, the adjacent connecting shafts 240 are inserted in alternate directions. That is, in the two adjacent connecting shafts 240, the tips (or the heads 241) are staggered (the connecting shafts 240 are inserted in different directions).

FIG. 5 is a diagram showing engagement between the sprocket wheel and the endless chain. As shown in FIG. 5, the tooth portion 302 formed with a predetermined width on the circumference of the main sprocket wheel 300 is inserted into the gap 210S (see FIG. 3) formed when the chain links 210 are connected, and meshes with each other. As shown in FIG. 1, as the main sprocket wheel 300 rotates, the endless chain 200 circulates in the settling tank A in the clockwise direction (CW) as shown in FIG. Is scraped by the sludge pit (discharge groove) 15.

FIG. 6 is a sectional view of the support member 600. A bottom portion 600S of the support member 600 is fixed to the wall surface of the settling basin A, and a constriction portion 610 for rotatably engaging the main sprocket wheel 300 or the driven sprocket wheel 400 is provided on the upper portion. In order to secure strength, the support member 600 preferably has a thickness D1 of the constricted portion 610 of 12 mm or more, a thickness D2 of the shoulder portion 620 of 15 mm or more, and a thickness D3 of the body portion 630 of 13 mm or more. The support member 600 may generate a rubbing sound because the main sprocket wheel 300 or the driven sprocket wheel 400 rotates and slides. In such a case, the supporting member 600, the main sprocket wheel 300, and the driven sprocket wheel 400 may be made of a material having excellent slidability, for example, UHMW (ultra high molecular weight polyethylene) used for resin bearings. Good.

As described above, the sludge scraper 1 according to the present embodiment causes the long flight body 100 to travel in the direction perpendicular to the longitudinal direction thereof to remove sludge accumulated on the bottom BT of the settling tank A. It is the sludge scraping machine 1 that scrapes up. The sludge scraper 1 is disposed in a sedimentation basin, and a pair of endless chains 200 in which a plurality of chain links 210 in which a plurality of flight bodies 100 are fixed at predetermined intervals are pivotally attached by a connecting shaft to endlessly connect, It is provided with a main sprocket wheel 300 and a driven sprocket wheel 400 that scrape sludge deposited on the pond bottom BT by the flight body 100 by circulatingly driving the stretched endless chain 200.

In the sludge scraper 1, the chain link 210 and the connecting shaft 240 of the endless chain 200 are composed of a PC. Therefore, the sludge scraper 1 is resistant to corrosion and inexpensive. Further, the tensile strength of PC is higher than that of POM, and the chain elongation due to deterioration over time is small. Further, since it is lighter in weight than the sludge scraper made of stainless steel, the construction period at the site can be shortened and the construction cost can be reduced as compared with the conventional one. Further, since PC does not release harmful substances such as formaldehyde unlike POM (polyacetal or polyoxymethylene), it can be used not only in sewage treatment but also in water treatment. Further, since the PC is easier to reuse than the POM, the resources can be effectively used.

Furthermore, when the PC is not colored or is colored to the extent that it has a light-transmitting property (to the extent that the internal state can be seen), the chain link 210 and the connecting shaft 240 have a light-transmitting property. It is possible to accurately grasp the state of the bubbles in the. That is, in the present embodiment, the translucency of the PC that constitutes the members such as the chain link 210 and the connecting shaft 240 means that the bubbles mixed in the members are visible light (visible light) from the outside of the members. (Light with a wavelength of about 360 nm to 830 nm)).

When the chain link 210 and the connecting shaft 240 are molded by a PC, if air bubbles are mixed inside during the process such as injection molding, the strength of the chain link 210 and the connecting shaft 240 may be insufficient. Further, even if bubbles are mixed, there is no problem in strength as long as they are minute bubbles mixed in the central portion of the member, and strength is affected for bubbles larger than a predetermined size mixed near the surface of the member. May affect.

When the PC is not colored or is colored to the extent that it has a light-transmitting property (to the extent that the internal state can be seen), the chain link 210 and the connecting shaft 240 have a light-transmitting property, and the molded chain link 210 and the connecting shaft 240 are assembled. The state of bubbles (presence/absence of bubbles, mixing position, size, etc.) can be easily visually grasped before, and defective products or those having a possibility of defective can be excluded before assembly.

Even if each bubble of the chain link 210 and the connecting shaft 240 is small, a large number of chain links 210 and the connecting shaft 240 are required to form the long endless chain 200. Therefore, it is possible to provide the endless chain 200 excellent in strength and durability by checking the bubbles one by one and preliminarily selecting a large number of non-defective chain links 210 and the connecting shaft 240 to configure the endless chain 200. Is possible. Particularly, since the endless chain 200 used in the sludge scraper 1 is driven to circulate in dirty water with poor visibility, it is very difficult to check the state of the endless chain 200 during operation. Therefore, it is very important in the sludge scraper 1 to configure the endless chain 200 by selecting the highly reliable chain link 210 and the connecting shaft 240.

In addition, the sludge scraper 1 and the endless chain 200 according to the present embodiment further include a retaining hook 250 attached to one end side of the connecting shaft 240 inserted into the chain link 210, and the pin hook 250 is composed of a PC. It is characterized by Since the pin hook 250 is made of PC, it is possible to provide the inexpensive endless chain 200 having higher tensile strength than POM, higher durability due to aging deterioration, stronger corrosion than stainless steel, and less expensive.

Further, since the component of the connecting shaft 240 that connects the chain link 210 is PC instead of nylon, it is possible to reduce the possibility that the connecting shaft 240 swells like nylon and the chain link 210 does not move smoothly (splashes). You can Further, since the coefficient of thermal expansion is lower than that of POM or nylon, it is possible to reduce the risk of the endless chain 200 derailing from the main sprocket wheel 300 or the driven sprocket wheel 400.

Further, the sludge scraper 1 and the endless chain 200 according to this embodiment are characterized in that the pin hook 250 is provided with a hollow hole 250H. In such a sludge scraper 1, since the pin hook 250 for preventing the connecting shaft 240 from coming off is made of PC, it has higher tensile strength than POM, higher durability due to aged deterioration, and more resistant to corrosion than stainless steel. It is possible to provide an inexpensive sludge scraper 1. Further, since the pin hook 250 is provided with the hollow hole 250H, it is possible to prevent air bubbles from being mixed in during molding by the PC. Since the air bubbles are not mixed, the strength of the pin hook 250 can be increased.

In addition, the sludge scraper 1 and the endless chain 200 according to the present embodiment are characterized in that, in the plurality of connecting shafts 240 that connect the plurality of chain links 210, the adjacent connecting shafts 240 are inserted in alternate directions. .. As a result, the imbalance in the elongation of the endless chain 200 due to the asymmetry of the shape of the connecting shaft 240 is suppressed, and the straightness of the endless chain 200 in the traveling direction is easily maintained.

Further, the sludge scraper 1 and the plurality of chain links 210 of the endless chain 200 according to the present embodiment each have a tubular base portion 211 having a first through hole (boss) 210H for inserting the connecting shaft 240. , A pair of plate parts 220 and 230 extending symmetrically in the vertical direction with respect to the longitudinal direction from both ends 211A and 211B of the base part 211, respectively.

The plate portions 220 and 230 surround the second through holes (bosses) 220H and 230H for inserting the connecting shaft 240 on the side opposite to the base portion 211 and the second through holes 220H and 230H. In this manner, the plate portions 220 and 230 have the first rib portions 220D and 230D that are perpendicular to the inner main surfaces 220A and 230A facing each other and the outer main surfaces 220B and 230B on the opposite side. And

As described above, the pair of plate portions 220 and 230 forming each chain link 210 of the sludge scraper 1 according to the present embodiment has the second through hole for inserting the connecting shaft 240 on the side opposite to the base portion 211. It has (bosses) 220H and 230H. The second through holes 220H and 230H are surrounded by the plate portions 220 and 230 in a direction perpendicular to the inner main surfaces 220A and 230A facing each other and the outer main surfaces 220B and 230B opposite to the inner main surfaces 220A and 230A. It has the raised 1st rib part 220D, 230D. Therefore, even if each member of the chain link 210 is made of a synthetic resin material, sufficient strength can be obtained.

In addition, the pair of plate portions 220 and 230 of the plurality of chain links 210 of the sludge scraper 1 and the endless chain 200 according to the present embodiment are respectively raised in the vertical direction with respect to the outer main surfaces 220B and 230B, and Since the second rib portions 220E and 230E extending from the through hole 210H to the second through holes 220H and 230H are provided, the strength can be further increased.

In addition, in the sludge scraper 1 and the endless chain 200 according to the present embodiment, the second rib portions 220E and 230E are substantially Y-shaped and branched from the first through hole 210H toward the second through hole 230H. It is characterized by being provided in the mold. In this way, the second rib portions 220E and 230E are provided in the Y-shape that is divided into two hands on the second through holes 220H and 230H side, so that the gap between the pair of plate portions 220 and 230 is opened. The reinforcing effect on the second through holes 220H and 230H side can be further enhanced.

Further, PET, PEN or PC which is a synthetic resin constituting each member of the main sprocket wheel 300 and the driven sprocket wheel 400 of the sludge scraper 1 according to the present embodiment is transparent or translucent in an uncolored state, That is, it is preferably not crystallized.

PET, PEN, or PC is transparent or translucent to visible light in the non-crystalline state (in the non-colored state), but when crystallized, it becomes white or milky white in the non-colored state. When PET, PEN, or PC is crystallized, it becomes vulnerable to external force, and cracks or chips easily occur. The endless chain 200 of the sludge scraper, the main sprocket wheel 300 and the driven sprocket wheel 400 have a large force (usually a force of 500 kg or more is applied, and it is required that the product performance does not break even if a force of 3000 kg is applied). Since it is added, it is preferably not crystallized.

The "amorphous state (non-crystallized state)" in this embodiment refers to a case where the amorphous state or the crystallinity is considerably low in the practical state, or the crystal size is fine. That said, in that case PET, PEN or PC becomes the transparent plastic. On the other hand, when the degree of crystallinity is high to some extent in a practical state, it becomes an opaque plastic. This is because it is almost impossible to crystallize the entire polymer because the polymer is a large molecule. As a whole, microcrystalline and non-crystalline parts are mixed, and the refractive index of the crystalline and non-crystalline parts are different, so the interface It is thought that light refraction and irregular reflection occur at the point, and as a result, it becomes opaque as a whole.

The synthetic resin forming each member of the main sprocket wheel 300 and the driven sprocket wheel 400 to which such a large force is applied is cracked by using non-crystallized PET, PEN or PC which is transparent or translucent in an uncolored state. It is possible to provide the sludge scraping machine 1 which is hard to be chipped and has sufficient strength.

Further, the thickness D1 of the front end portion T1 of the pair of plate portions 220 and 230 included in the chain link 210 that constitutes the endless chain 200 of the sludge scraper 1 according to the present embodiment is 7 mm or more, and the thickness of the rear end portion T2. D2 is 5 mm or more. Therefore, it is possible to secure sufficient strength in the chain link 210 to which a large force is applied, and it is possible to suppress the possibility that the endless chain 200 may have a problem such as cutting.

In addition, the sludge scraper 1 according to the present embodiment surrounds the second through holes 220H and 230H of the pair of plate portions 220 and 230 included in the chain link 210 that forms the endless chain 200 so as to surround the plate portion. You may provide the 3rd rib part with a thickness of 0.5 mm-1.5 mm which each protruded in the perpendicular direction with respect to inner side main surface 220A, 230A which 220,230 opposes. In this case, it is preferable that the third rib portion has a trapezoidal cross-sectional shape, and the uppermost surface of the trapezoid is a flat surface having a predetermined width.

By providing the third rib portion, a force is applied in parallel with the longitudinal direction of the endless chain 200, and it is effective that an unreasonable force is applied to the chain link 210 in the licking direction, such as twisting or twisting. Can be suppressed. For this reason, it is possible to more effectively suppress the possibility that the endless chain 200 may have a problem such as cutting.

(Example of tensile strength)
Here, the test results of the tensile strength of PC and POM in the material of the endless chain will be described.
In the tensile strength test, three samples each having the chain link 210 and the connecting shaft 240 made of PC and three samples having the same shape of the chain link 210 and the connecting shaft 240 made of POM were prepared. Samples composed of PC are referred to as sample-PC1, sample-PC2, and sample-PC3. Samples composed of POM are referred to as sample-POM1, sample-POM2, and sample-POM3.

The sample is a triple chain in which three chain links 210 are connected by a connecting shaft 240. In the tensile strength test, both ends of the sample were held and the maximum strength (the force applied when pulling until the chain link 210 or the connecting shaft 240 was broken) when the sample was pulled at a speed of 2 mm/min was measured. The test results are shown in Tables 1 and 2 below. Table 1 shows the test results of the sample composed of PC, and Table 2 shows the test result of the sample composed of POM. Note that the above-mentioned breakage does not mean that the chain link 210 or a part of the connecting shaft 240 is cracked or chipped, but a triple chain in which three chain links 210 are connected by the connecting shaft 240 is completely broken. It is a state.

As a result of the above tensile strength test, the maximum strength average of the sample made of PC is about 35.05 kN, and the maximum strength average of the sample made of POM is about 31.17 kN. Thus, it can be seen that PC has higher strength than POM. In particular, the endless chain 200 of the sludge scraper 1 is required to have high strength because several hundred to one thousand of the chain links 210 are connected to perform a circulating operation. It can be seen that by using PC as the endless chain 200 of the sludge scraper 1, it is possible to exhibit characteristics (particularly tensile strength) superior to POM.

(Other embodiments)
FIG. 7 is a diagram showing meshing between a sprocket wheel and an endless chain in another embodiment. In the above-described embodiment, as shown in FIG. 5, the tooth portion 302 formed with a predetermined width on the circumference of the main sprocket wheel 300 is inserted into the gap 210S formed when the chain links 210 are connected to engage with each other. ..

However, the engagement between the sprocket wheel and the endless chain is not limited to the above embodiment, and for example, as shown in FIG. 7, a recess (notch) 210N is provided in the lower portion of the chain link 210 that constitutes the endless chain 200, and the chain link 210 The engaging pin 300P included in the main sprocket wheel 300 may be engaged with the recess (notch) 210N in the lower part of the above, and the rotational force of the main sprocket wheel 300 may be transmitted to the chain link 210.

As described above, according to the sludge scraper and the endless chain of the present invention, it is possible to provide the sludge scraper and the endless chain having sufficient strength and resistant to corrosion.

As described above, the present invention can provide a sludge scraper and an endless chain that have sufficient strength and are resistant to corrosion. Therefore, in a sewage treatment plant, it is suitable for a sludge scraping machine that scrapes up sludge accumulated on the bottom of the final settling tank and collects it in a mud collecting pit. Further, since the PC is used as the endless chain, it can be used in a water supply site.

1 Sludge scraper 15 Sludge pit (discharge groove)
100 Flight body 200 Endless chain 210 Chain link 210H First through hole (boss)
211 Bases 211A, 211B Base Ends 220, 230 Plates 220H, 230H Second Through Holes (Boss)
220A, 230A Inner main surface 220B, 230B Outer main surface 220C, 230C First rib part 220D, 230D First rib part 220E, 230E Second rib part 231 Central part 232 Branch part 235 Rib part 240 Connecting shaft 241 head Part 243 Notch part 250 Pin hook 250H Middle hole 270 Fixing member 300 Main sprocket wheel 301 Through hole 302 Teeth 305H Middle hole 400 Driven sprocket wheel 500 Driving means 510 Transmission belt 520 Motor 600 Supporting member 610 Constriction part 620 Shoulder part 630 Body part 600S Bottom part 2301 Convex part 2411 Flat part A Settling pond WL Water surface BT Pond bottom

Claims (14)

A sludge scraping machine that runs a long flight body in a direction perpendicular to its longitudinal direction to scrape sludge accumulated on the bottom of a sedimentation tank,
A pair of endless chains in which the plurality of flight bodies are endlessly connected by pivotally attaching a plurality of chain links fixed at a predetermined interval by a connecting shaft,
The main sprocket wheel and the driven sprocket wheel that scrape the sludge settled on the bottom of the pond by circulating the endless chain arranged in the settling basin by circulating the sprocket wheel and the driven sprocket wheel,
Each of the plurality of chain links,
A tubular base portion having a first through hole (boss) for inserting the connecting shaft;
A pair of plate portions extending symmetrically in the direction perpendicular to the longitudinal direction from both ends of the base portion,
The pair of plate portions are each
A second through hole (boss) for inserting the connecting shaft on the side opposite to the base,
A cylindrical first rib portion that bulges in a direction perpendicular to an outer main surface opposite to the inner main surface where the plate portions are opposed to each other so as to surround the second through hole.
One central portion protruding in the direction perpendicular to the outer main surface and extending from the central portion of the plate portion to the first through hole side, and from the central portion to the second through hole side A second rib portion provided in a substantially Y shape, which is divided into two hands and spreads at a predetermined angle and extends to the first rib portion.
The endless chain is
A sludge scraper , wherein the plurality of chain links are pivotally attached by a connecting shaft so as to be connected endlessly so that the first rib portion is on the front side in the traveling direction of the endless chain . The sludge according to claim 1, wherein the height of each ridge of the second rib portion is provided so as to gradually increase from the first through hole to the second through hole. Oyster The plurality of rib portions different from the first rib portion and the second rib portion are provided radially around the first rib portion, according to claim 1 or claim 2. The described sludge scraper. The sludge scraper according to claim 1, wherein the chain link and the connecting shaft of the endless chain are made of PC (polycarbonate). Further comprising a pin hook for retaining attached to one end side of the connecting shaft inserted into the chain link,
The sludge scraper according to any one of claims 1 to 4, wherein the pin hook is formed of a PC. The sludge scraper according to claim 5 , wherein the pin hook is provided with a hollow hole. The sludge scraper according to any one of claims 1 to 6 , wherein among the plurality of connecting shafts that connect the plurality of chain links, the adjacent connecting shafts are inserted in alternate directions. An endless chain used in a sludge scraping machine that runs a long flight body in a direction perpendicular to its longitudinal direction to scrape sludge accumulated on the bottom of a sedimentation pond,
The endless chain is
The plurality of flight bodies are endlessly connected by pivotally connecting a plurality of chain links fixed at a predetermined interval by a connecting shaft,
Each of the plurality of chain links,
A tubular base portion having a first through hole (boss) for inserting the connecting shaft;
A pair of plate portions extending symmetrically in the direction perpendicular to the longitudinal direction from both ends of the base portion,
The pair of plate portions are each
A second through hole (boss) for inserting the connecting shaft on the side opposite to the base,
A cylindrical first rib portion that bulges in a direction perpendicular to an outer main surface opposite to the inner main surface where the plate portions are opposed to each other so as to surround the second through hole.
One central portion protruding in the direction perpendicular to the outer main surface and extending from the central portion of the plate portion to the first through hole side, and from the central portion to the second through hole side A second rib portion provided in a substantially Y shape, which is divided into two hands and spreads at a predetermined angle and extends to the first rib portion.
An endless chain characterized in that the plurality of chain links are pivotally attached by a connecting shaft so as to be connected endlessly so that the first rib portion is on the front side in the traveling direction of the endless chain. 9. The endless portion according to claim 8, wherein the height of each ridge of the second rib portion is provided so as to gradually increase from the first through hole to the second through hole. chain. 10. A plurality of rib portions different from the first rib portion and the second rib portion are provided radially around the first rib portion, according to claim 8 or claim 9. The listed endless chain. The endless chain according to any one of claims 8 to 10, wherein the chain link and the connecting shaft are made of PC (polycarbonate). Further comprising a pin hook for retaining attached to one end side of the connecting shaft inserted into the chain link,
The endless chain according to any one of claims 8 to 11, wherein the pin hook is a PC. The endless chain according to claim 12 , wherein the pin hook has a hollow hole. The endless chain according to any one of claims 8 to 13 , wherein in the plurality of connecting shafts that connect the plurality of chain links, the adjacent connecting shafts are inserted in alternate directions.

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