JP6079285B2 - Classification device - Google Patents

Description

  The present invention relates to a classification device for separating solid organic matter, sand and silt.

  Dredged soil may contain not only earth and sand but also solid organic matter such as bark, wood fragments, and leaves. In the case where soil is used as a construction material or the like, mixing of solid organic matter may be a problem. In this case, it is necessary to separate the solid organic matter from the soil.

  Therefore, a classifying device is provided in which a recovery net is provided over the entire horizontal surface of the cylinder, and a solid-liquid mixture of soil and water is introduced into the cylinder, and the earth and sand and solid organic matter are separated by the recovery net. It is disclosed (for example, Patent Document 1).

JP 2011-202501 A

  In addition, depending on the purpose of use of the soil, there is a request to separate only the sand, but the earth and sand constituting the soil contains not only the sand but also silt having a particle size smaller than that of the sand. It is necessary to separate sand or silt.

  However, in the technique of Patent Document 1, sand having a relatively large particle size and silt having a relatively small particle size cannot be separated from the earth and sand.

  Then, this invention aims at provision of the classification apparatus which can isolate | separate sand, a solid organic substance, and silt from earth and sand with simple structure, respectively.

In order to solve the above-described problem, the classification device of the present invention includes a storage tank capable of storing a solid-liquid mixture containing sand, solid organic matter, silt, and water, and a solid-liquid mixture in the storage tank. When the water level reaches a predetermined level, the overflow portion that causes the solid-liquid mixture in the storage tank to overflow to the outside, the side surface of the storage tank in which the overflow portion is provided, and the opposing surface that faces the side surface Crossing the flow direction of the swirl flow, a baffle plate provided opposite to the side surface, swirl flow forming means for forming a swirl flow between the facing surface and the baffle plate And a sieve section having a plurality of holes through which solid organic matter can be captured and sand can pass.

  Further, the swirl flow forming means may form a swirl flow swirling around a rotation axis extending in the horizontal direction.

  Further, the sieving portion may be provided so as to intersect with the flow direction of the downward flow in the swirling flow.

  Further, the sieving portion may be provided in a region where a downward flow is formed in the storage tank and at the most vertically upper position.

  Moreover, the horizontal cross-sectional area between the side surface and the baffle plate in the storage tank may be gradually reduced as it goes vertically downward.

  According to the present invention, sand, solid organic matter, and silt can be separated from earth and sand with a simple configuration.

It is a figure for demonstrating the specific structure of a classification apparatus. It is a figure for demonstrating the specific structure of a sieve part. It is a figure for demonstrating the structural example of a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  In recent years, soil has been decontaminated because there has been a situation where the soil is contaminated with radioactive substances over a wide area. Examples of soil decontamination include a technique of removing contaminated soil (hereinafter referred to as “contaminated soil”) and storing it in a storage facility, and installing uncontaminated soil instead of the removed contaminated soil. However, when soil contamination is wide-ranging, it is necessary to store a huge amount of contaminated soil, and it is not realistic to secure a huge site and construct a storage facility.

  The inventor of the present application has found that many radioactive substances are adsorbed on solid organic matter such as bark, wood fragments, leaves mixed in soil. Moreover, it turned out that comparatively much radioactive substance has adhered to silt (it is prescribed | regulated as 75 micrometers or less by JIS) with a comparatively small particle size among the earth and sand which comprises soil. Therefore, by separating the contaminated solid organic matter and silt from the contaminated soil, it is possible to reduce the volume of the material contaminated with the radioactive material. In this embodiment, a classification device 100 that can separate sand, solid organic matter, and silt from soil will be described.

(Classifier 100)
FIG. 1 is a diagram for explaining a specific configuration of the classification device 100. As shown in FIG. 1, the classification device 100 includes a storage tank 110, a partition plate 120, a swirl flow forming unit 130, an overflow unit 140, a baffle plate 150, a sieve unit 160, and a solid matter removing unit 170. It is comprised including. In FIG. 1, the flow of the solid-liquid mixture ML and the silt-containing liquid L0 is indicated by solid arrows, and the swirl flow is indicated by broken arrows. In FIG. 1 of the present embodiment, the X axis, the Y axis, and the Z axis that intersect perpendicularly are defined as illustrated.

  The storage tank 110 is a tank for storing a solid-liquid mixture ML containing sand, solid organic matter, silt, and liquid (here, water), and is vertically downward (positive direction of the Z axis in FIG. 1). This is a tank in which the horizontal cross-sectional area of the inner region gradually decreases as it goes to. If it demonstrates in detail, the storage tank 110 is comprised so that the horizontal cross-sectional area between the side surface 110a mentioned later and the baffle plate 150 in the storage tank 110 may decrease gradually as it goes to the perpendicular downward direction. The solid-liquid mixture ML is introduced into the storage tank 110 by the introduction unit 102. The introduction unit 102 is configured by a pump, for example, and introduces the solid-liquid mixture ML into the storage tank 110. The introduction unit 102 may introduce the solid (soil) composed of sand, solid organic matter, and silt, and the liquid separately into the storage tank 110. In this case, the introduction unit 102 is It is good to comprise with the dredge apparatus which introduces a mixture into the storage tank 110, and the pump which introduces a liquid.

  In addition, a partition plate 120 that partitions the inner region of the storage tank 110 in the vertical direction (Z-axis direction in FIG. 3) is provided in the storage tank 110. The partition plate 120 is provided with a plurality of holes 120a. The diameter of the hole 120a is 5 mm to 15 mm, preferably 10 mm. If the diameter of the hole 120a is less than 5 mm, the gas flow from the swirl flow forming means 130 to the upper side of the partition plate 120 may be hindered. Further, if the diameter of the hole 120a is 15 mm or more, the flow velocity of the air rising through the partition plate 120 is too slow, and sand falls from above the partition plate 120 to below the partition plate 120. Therefore, by setting the diameter of the hole 120a to 5 mm to 15 mm, a situation in which the gas flow from the swirling flow forming means 130 to the upper side of the partition plate 120 is obstructed is avoided, and the flow velocity (momentum) of the swirling flow to be described later. In addition, it is possible to prevent a situation where sand falls below the partition plate 120. Due to the configuration in which the partition plate 120 is provided in the storage tank 110, the holes (gas delivery ports) of the air diffuser 130a of the swirl flow forming means 130, which will be described later, are blocked by solid matter (sand, solid organic matter, etc.), and aeration efficiency Can be avoided. Hereinafter, of the internal region of the storage tank 110, the region above the partition plate 120 is referred to as an upper region, and the region below the partition plate 120 is referred to as a lower region.

  An air diffuser 130 a constituting the swirl flow forming means 130 is disposed below the partition plate 120 (lower region) in the storage tank 110. The swirl flow forming means 130 includes, for example, an air diffuser or diffuser plate having a hole diameter of 300 μm or more, an air diffuser 130a configured by a simple tube, and a blower 130b that sends gas (for example, air) to the air diffuser 130a. The gas is supplied to the solid-liquid mixture ML from the bottom surface side in the storage tank 110 to aerate the solid-liquid mixture ML.

  In this way, a swirling flow (indicated by a dashed arrow in FIG. 3) that swirls around the rotation axis extending in the horizontal direction (Y-axis direction in FIG. 1) is formed in the storage tank 110, and aeration is performed. As a result, silt adsorbed (attached) to sand and solid organic matter is dispersed in water.

  The overflow part 140 is a tube formed on the side surface 110a of the storage tank 110, and the silt-containing liquid in the storage tank 110 when the solid-liquid mixture ML in the storage tank 110 reaches a predetermined water level. Overflow L0 to the outside.

  The baffle plate 150 is a plate provided between the side surface 110a where the overflow portion 140 is provided in the storage tank 110 and the facing surface 110b facing the side surface 110a and facing the side surface 110a. Further, the baffle plate 150 is provided across the liquid surface of the solid-liquid mixture ML in the storage tank 110. Further, the position of the baffle plate 150 in the horizontal direction (X-axis direction in FIG. 1) is biased toward the overflow section 140. In the present embodiment, the baffle plate 150 is positioned between the overflow portion 140 and the end portion 120b of the partition plate 120 on the overflow portion 140 (side surface 110a) side in the horizontal direction. That is, the swirl flow forming means 130 supplies the gas between the facing surface 110b and the baffle plate 150 to aerate the solid-liquid mixture ML. If it does so, the baffle plate 150 will suppress the movement to the overflow part 140 of the bubble formed with the gas introduce | transduced by the rotational flow formation means 130. FIG.

  Therefore, it is possible to prevent air bubbles aerated from the bottom surface side of the storage tank 110 from entering a settling region (a region surrounded by a one-dot chain line in FIG. 1) formed between the baffle plate 150 and the overflow portion 140. be able to. As a result, in the region formed between the baffle plate 150 and the facing surface 110b (hereinafter referred to as “swirl region”), the solid-liquid mixture ML is agitated by aeration by the swirl flow forming means 130, and the sand Silt is desorbed (desorbed) from solid organic matter, and in the sedimentation area, sand and solid organic matter are settled using the difference in sedimentation rate (falling speed) between sand and solid organic matter and silt. Sand and solid organics are separated from mixture ML.

  More specifically, the mass density (specific gravity) decreases in the order of sand, silt, and solid organic matter, and the volume decreases in the order of solid organic matter, sand, and silt. The sedimentation rate is determined by the balance between mass density and size (Stokes' formula), and decreases in the order of sand, solid organic matter, and silt. Therefore, the sand and solid organic matter remain in the storage tank 110 because the sedimentation speed is larger than the speed at which the sand flows out from the storage tank 110 to the outside by the overflow section 140, and silt is removed from the storage tank 110 to the outside by the overflow section 140. Since the sedimentation speed is smaller than the speed at which it flows out into the water, it becomes a suspension and flows out from the overflow section 140 to the outside.

  Further, as described above, the storage tank 110 according to the present embodiment has a shape in which the horizontal cross-sectional area between the side surface 110a and the baffle plate 150 gradually decreases in the vertical direction. Sand and solid organic matter can be returned to the swirl zone.

  Thus, sand and solid organic matter remain in the storage tank 110, and the silt-containing liquid L0 containing silt from which sand and solid organic matter have been separated is discharged from the overflow section 140 to the outside. Moreover, in the storage tank 110, sand and solid organic matter become a swirl flow and swirl in the storage tank 110. Further, by continuing the turning, the sand is settled by utilizing the difference in the sedimentation speed (falling speed) between the sand and the solid organic matter, and the sand and the solid organic matter are separated.

  The sieve part 160 is provided so as to intersect with the flow direction of the swirl flow (in this embodiment, orthogonal), captures solid organic matter, and has a plurality of sieves (nets, nets) through which sand can pass (easy to pass). Net). The sieving part 160 is constituted by, for example, a net having an opening of 0.5 mm to 5 mm.

  FIG. 2 is a diagram for explaining a specific configuration of the sieve unit 160. As shown in FIG. 2A, in the present embodiment, the sieve part 160 includes an opening 210, a side part 212, and a bottom part 214. In the sieving portion 160, the opening portion 210 is provided orthogonal to the direction of flow of the swirl flow (indicated by a white arrow in FIG. 2). In the present embodiment, a plurality of holes 216 (for example, the hole diameter is 0.5 mm to 5 mm) are provided in the side surface portion 212 and the bottom surface portion 214 of the sieve portion 160.

  As described above, since the solid organic matter flows as a swirling flow, the solid organic matter can be captured by the sieving portion 160 by providing the sieving portion 160 in a direction intersecting with the swirling flow. Moreover, it becomes possible to capture | acquire solid organic matter efficiently by providing the sieve part 160 (specifically, bottom face part 214) in the direction orthogonal to the swirl flow. And it becomes possible to remove efficiently the solid organic substance to which many radioactive substances adhered from the solid-liquid mixture ML by pulling up the sieve part 160 which captured the solid organic substance from the storage tank 110.

  Moreover, the sieve part 160 is provided so as to intersect with the flow direction of the downward flow DF in the swirl flow. In this embodiment, the sieve part 160 is provided orthogonal to the flow direction of the downward flow DF, that is, along the horizontal plane (XY plane in FIG. 1).

  Thus, by providing the sieve part 160 so as to intersect with the flow direction of the downward flow DF, the solid organic matter can be held on the sieve part 160 even when the flow of the swirling flow is stopped. Therefore, it becomes possible to remove the solid organic matter from the solid-liquid mixture ML simply by pulling up the sieve portion 160 vertically upward.

  Furthermore, in the present embodiment, the sieving portion 160 is a region where the downward flow DF is formed in the storage tank 110, and is provided at a position that is most vertically upward. Since the solid organic matter has a smaller mass density than sand, it tends to float vertically upward. Therefore, by providing the sieving portion 160 in the position vertically above the region where the downward flow DF is formed, the solid organic matter can be captured at the place where the concentration (density) of the solid organic matter is the highest. Can be efficiently removed from the solid-liquid mixture ML.

  Moreover, since sand has a larger mass density than solid organic matter, it is difficult to float vertically upward. In other words, sand tends to sink vertically downward. Therefore, by providing the sieving part 160 at the most vertically upper position in the region where the downward flow DF is formed, the frequency of sand passing through the sieving part 160 can be reduced, and the sieving part 160 is blocked by sand. Can be suppressed.

  In addition, as shown in FIG. 2B, the sieve unit 160 may be configured by a support frame 220 and a flexible net 222 that is locked to the support frame 220. In this case, the support frame 220 maintains the opening of the net 222, and the opening is provided so as to intersect the flow direction of the swirl flow. Thus, by configuring the sieve part 160 with the support frame 220 and the mesh 222, the solid organic matter to which a large amount of radioactive material is adhered can be efficiently removed from the solid-liquid mixture ML simply by lifting the mesh 222 from the storage tank 110. It can be removed well. In addition, since the net 222 that has captured the solid organic matter can be easily exchanged with the new net 222, the solid organic matter can be discarded together with the net 222, and usability can be improved.

  Referring back to FIG. 1, the solid matter removing means 170 is composed of a grab type sand blaster, a bucket conveyor, and the like, and the sand that has settled and separated from the solid-liquid mixture ML in the storage tank 110 is outward from the storage tank 110. Take out. As described above, the amount of radioactive material adsorbed on sand is very small compared to solid organic matter and silt. Therefore, when the amount of radioactive material adsorbed on the sand is such that there is no influence even if it is returned to the original position by the configuration including the solid matter removing means 170, only the sand is returned to the original position, and only the solid organic matter and silt are returned. Can be separated.

  In addition, the classification device 100 of the present embodiment has a very small amount of radioactive material adsorbed on sand and silt compared to solid organic matter, and when sand and silt are not affected when returned to the original position. It is also possible to return to the original position and separate only the solid organic matter.

  As described above, according to the classifying device 100 according to the present embodiment, sand, solid organic matter, and silt can be separated from earth and sand with a simple configuration.

(Example)
A classification device 100 having a storage tank 110 having a shape shown in FIG. Moreover, the sieve part 160 was formed with a mesh having an opening of 1 mm. Then, a solid (soil) composed of sand, solid organic matter, and silt and water are charged into the storage tank 110, and a swirl flow is formed by the swirl flow forming means 130. Captured.

Subsequently, the VS (Volatile Solids: organic matter) / VS of the soil before being introduced into the storage tank 110, the residue settled in the storage tank 110, the trapped material by the sieving section 160, and the overflow material overflowed from the overflow section 140 TS (Total Solids) was measured. VS / TS is a value serving as an index of the content of organic matter. When VS / TS is large, the content of organic matter is high, and when VS / TS is small, the content of organic matter is low. In the examples, TS was defined as the weight after being dried at 110 ° C. until reaching a constant weight (dry weight), and the weight decreased when VS was heated at 550 ° C. for 30 minutes. The results are shown in Table 1 below.

  Referring to Table 1, it was confirmed that the VS / TS of the captured material was the highest among the soil, the residue, the captured material, and the overflow product, and the solid organic matter could be captured by the sieve unit 160. In addition, it was confirmed that the VS / TS of the residue was the lowest and the sand could be separated by the classifier 100 (sand remained in the storage tank 110).

  Moreover, the density | concentration of the radioactive cesium (Cs137) per dry weight of each of a soil, a residue, a capture thing, and an overflow was measured. The results are shown in Table 1 above. Here, the ratio when the concentration of radioactive cesium per dry weight of the residue is “1” is shown. Referring to Table 1, the concentration of radioactive cesium in the trap was found to be 38 times that of the residue. Therefore, it was confirmed that the soil can be efficiently decontaminated by removing the trapped material (solid organic matter) from the soil using the sieve unit 160. Moreover, since the radioactive cesium concentration of the overflow is 9 times that of the residue, it is confirmed that the soil can be efficiently decontaminated by separating the overflow (silt) using the classifier 100. It was.

(Modification)
In the above-described embodiment, the configuration in which the sieve unit 160 is provided so as to intersect with the flow direction of the downward flow DF in the swirling flow has been described. However, the position of the sieving portion 160 is not limited as long as it is provided so as to intersect with the flow direction of the swirling flow.

  FIG. 3 is a diagram for explaining a configuration example of a modification. In FIG. 3A, only the storage tank 110 and the sieve part 160 are extracted and shown for easy understanding. 3 (b) to 3 (d), the direction of the swirling flow is indicated by white arrows. As shown in FIG. 3 (a), the sieving part 160 (indicated by 160a, 160b, 160c in FIG. 3) may be provided so as to intersect with the flow direction of the swirl flow. It may be provided orthogonally or may be provided orthogonally to the flow direction of the upward flow UF.

  When the sieve portions 160a and 160b are provided perpendicular to the flow direction of the horizontal flow, as shown in FIGS. 3B and 3C, the surface arranged vertically below the surface 230 arranged vertically. 232 may be configured larger. With this configuration, in order to recover the solid organic matter captured on the surface 234 orthogonal to the flow direction of the horizontal flow, the solid organic matter can be recovered without dropping into the storage tank 110 when the sieve portions 160a and 160b are pulled up. it can.

  In addition, when the sieve portion 160c is provided orthogonal to the flow direction of the upward flow UF, as shown in FIG. 3D, the surface 230 arranged vertically and the surface 232 arranged vertically below are connected. The surface 236 to be inclined is inclined, and a locking surface 238 facing the surface 236 in the surface 232 is preferably formed. With such a configuration, in order to recover the solid organic matter captured on the surface 230 orthogonal to the flow direction of the upward flow UF, the solid organic matter can be guided to the surface 232 along the surface 236 when the sieve unit 160 is pulled up. it can. Further, by providing the locking surface 238, it is possible to prevent the solid organic matter from dropping from the surface 232 to the storage tank 110.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the example in which the swirling flow forming unit 130 is configured by the air diffuser 130a and the blower 130b has been described. However, the swirling flow forming unit 130 only needs to be able to form a swirling flow. You may comprise with the motor which rotationally drives the said rotary blade. Further, the swirl flow formed by the swirl flow forming means 130 is not limited to the swirl flow swirling around the rotation axis extending in the horizontal direction, and is a swirl flow swirling around the rotation axis extending in the vertical direction. Also good. Even in this case, the sieve unit 160 may be provided so as to intersect with the flow direction of the swirl flow.

  Moreover, in the said embodiment, although the sieve part 160 demonstrated and demonstrated as an example the structure provided orthogonally to the flow direction of a swirl flow, if it cross | intersects the flow direction of a swirl flow, there will be no limitation in an angle. .

  Moreover, in the said embodiment, although the horizontal cross-sectional area between the side surface 110a and the baffle plate 150 in the storage tank 110 is gradually reduced as it goes to the perpendicular downward direction, the shape of the storage tank 110 is not limited.

  INDUSTRIAL APPLICABILITY The present invention can be used for a classification device that separates solid organic matter, sand, and silt.

DESCRIPTION OF SYMBOLS 100 ... Classification apparatus 110 ... Containment tank 130 ... Swirling flow formation means 140 ... Overflow part 150 ... Baffle plate 160 ... Sieve part

Claims (5)

A storage tank capable of storing a solid-liquid mixture containing sand, solid organic matter, silt, and water;
When the solid-liquid mixture in the storage tank reaches a predetermined water level, an overflow section that overflows the solid-liquid mixture in the storage tank to the outside;
Among the storage tank, a baffle plate provided between the side surface where the overflow portion is provided and the opposing surface facing the side surface, and provided facing the side surface,
Swirl flow forming means for forming swirl flow between the facing surface and the baffle plate ;
A sieving part that is provided crossing the flow direction of the swirling flow, captures the solid organic matter, and has a plurality of holes through which the sand can pass;
A classification device characterized by comprising:   The classification device according to claim 1, wherein the swirl flow forming unit forms a swirl flow swirling around a rotating shaft extending in a horizontal direction.   The classification device according to claim 2, wherein the sieving portion is provided so as to intersect with a flow direction of the downward flow in the swirling flow.   The classification device according to claim 3, wherein the sieving portion is an area where the downward flow is formed in the storage tank, and is provided at a position that is vertically uppermost. The classification device according to any one of claims 1 to 4, wherein a horizontal cross-sectional area between the side surface and the baffle plate in the storage tank gradually decreases in a vertical downward direction.

Images