JP2006000696A - Classifier of sand for aggregate and classification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a classifier that is capable of efficiently recovering fine sand with good quality usable as sand for aggregate from natural sand, crushed sand and recycled sand, and to provide a classification method. <P>SOLUTION: The classifier of the sand for aggregate has a conduit to supply the sand for aggregates towards into a wet type classifier 5 by a high pressure water jet and has a fine sand recovering device 20 immediately below the wet type classifier 5 to classify the sands for aggregates discharged from the conduit. The fine sand discharged from the fine sand recovering device 20 is returned to the wet type classifier 5 via a washing device 3 and a sending pipe 4 under pressure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aggregate sand classification apparatus and classification method, and in particular, it is possible to efficiently classify and recover high-quality sand that can be used as concrete aggregate from natural sand, crushed sand, and recycled sand. The present invention relates to a classification device and a classification method that can effectively use aggregate resources.

  Traditionally, in Japan, aggregate sand is collected from rivers, mountains, or the sea. However, since these sands have been collected in large quantities, it has become difficult in recent years to collect good quality sand from nature. A major cause of the deterioration of the quality of natural sand is the presence of clay stones, clay blocks, and other soft stones in the sand. If these soft stones are mixed in the sand, the specific gravity and water absorption The properties such as properties are deteriorated, and it cannot be used as a concrete aggregate. Further, in addition to soft stone, wood chips, grass roots, and the like are often mixed in the sand, and it is necessary to reliably remove these impurities for use as a concrete aggregate (see, for example, Patent Document 1). ).

In Patent Document 1, as shown in FIG. 7, a hopper 81 into which raw material sand is introduced, and raw material sand discharged from the hopper 81 is washed with water through a belt feeder 82 and a belt conveyor 83, and a large diameter component and a medium diameter component. Separating equipment 84 for separating into small diameter components, crushing equipment 85 for crushing clay lumps and the like contained in the small diameter components separated by the sorting equipment 84, and light impurities such as wood chips from the raw material processed by the crushing equipment 85 A concrete aggregate comprising an impurity removing facility 86 to be removed and a classifying facility 87 for dividing the raw material processed by the impurity removing facility 86 into fine sand and coarse sand, and classifying the raw material sand into fine sand 88 and coarse sand 89. An apparatus for producing sand is described.
JP-A-11-276924

  However, in the concrete aggregate sand manufacturing apparatus described in Patent Document 1, it is difficult to reliably remove soft stone and impurities mixed in the sand, and it is used as aggregate from natural sand. It is difficult to efficiently obtain good quality sand that can be used.

  In addition, it is difficult to efficiently collect fine sand having a size below a certain level.

  The present invention has been made in view of such problems of the prior art, and its purpose is to provide a high-quality sand containing fine sand that can be used as aggregate sand from natural sand, crushed sand and recycled sand. An object of the present invention is to provide a classification device and a classification method capable of efficiently collecting sand.

  In order to achieve the above object, the present invention discharges the aggregate sand together with a high-pressure water jet into the wet classifier, classifies the aggregate sand with the wet classifier, and then with the water from the wet classifier. As a fine sand collection device for collecting the small-diameter aggregate sand discharged (under the sieve), a spray device for generating a circulating flow for floating the fine-diameter aggregate sand and the floated bone A finely sized bone by a skillful combination of a baffle plate that resists the smooth flow of the material sand circulation flow and an inclined plate that slopes downward so as to reach the side wall opening from just below the water surface. The material sand can be efficiently recovered.

  Moreover, since the aggregate sand is discharged by a high-pressure water jet, when it comes into contact with the wet classifier sieve device, the impact of the impact can remove the corners of the sand and smooth the surface. It is done.

  Furthermore, the effect of preventing clogging of the sieve device of the wet classifier can be expected by the jet flow of high-pressure water.

  Since the present invention is configured as described above, there is provided a classification device and a classification method capable of efficiently recovering high-quality sand including fine sand that can be used as aggregate sand from natural sand, crushed sand and recycled sand. Can be provided.

  That is, the aggregate sand classification device of the present invention is an aggregate sand classification device including a wet classifier and a fine sand collection device for classifying aggregate sand, A pipe having a high-pressure water jet, and a wet classifier for wet-classifying aggregate sand discharged from the pipe at high pressure, and having a small diameter discharged together with water from the wet classifier A fine sand collecting device for collecting the aggregate sand is arranged directly under the wet classifier, and an inclined plate that is inclined downward so as to reach the opening of the side wall from directly below the water surface of the fine sand collecting device is installed. A baffle plate is installed in the vertical direction of the area on the inclined plate, and a spray device that discharges water toward the side wall opening of the fine sand collecting device is installed in the vicinity of the baffle plate, together with water from the wet classifier The fine sand to be discharged is introduced into the region on the inclined plate, and the fine sand collecting device is introduced. The opening provided in the side wall is characterized in that connected to the conveying line of the sand for aggregate.

  According to the present invention, on a slanted plate partitioned by a slanted plate of a fine sand recovery device in which fine-diameter aggregate sand (under the sieve) discharged together with water from a wet classifier is arranged directly under the wet classifier. In this region, a circulating flow is formed by the spray water discharged from the spray device, and the fine-diameter aggregate sand that floats up along with the circulating flow acts as a resistance against the baffle plate. The small-diameter aggregate sand that slides down on the inclined plate and slides on the inclined plate due to the pressure of spray water passes through the opening provided in the side wall of the fine sand collecting device to the aggregate sand conveying line. Aggregated sand containing fine-sized sand that is supplied and discharged again from this conveying pipe at high pressure is classified by a wet classifier, and some fine-sized aggregate sand is converted to large-sized aggregate sand. Accompanying it can be recovered as a product. In this way, in the process of circulating the fine-diameter aggregate sand between the wet classifier and the fine sand collecting device, some fine-diameter aggregate sand is recovered as a product together with the large-diameter aggregate sand. be able to. In the present specification, the fine aggregate sand is an aggregate sand having a particle size of less than 0.15 mm. For example, the fine-diameter sand for aggregates is preferably contained in a certain amount or more with respect to the sand for aggregates in order to improve the appearance of the exposed concrete building. However, if the amount is too large, the strength of the concrete may be insufficient. Therefore, it is preferable to contain fine aggregate sand within a range of 5% by weight or less.

Moreover, in order to enjoy the further smoothing effect of sand and the clogging prevention effect of the sieving device, the pressure of the high-pressure water jet is preferably 1.0 kg / cm ² or more. However, if the pressure of the washing water is too strong, the equipment may be damaged, and there is a disadvantage that the wear of the sieve is accelerated. Therefore, it is preferably 50.0 kg / cm ² or less, and 3.0 kg / cm. More preferably, it is ^{2 to} 10.0 kg / cm ² .

  Further, the mixing ratio of water and sand is preferably 0.7 to 1 volume of sand with respect to 1 volume of water in order to enhance the cleaning effect of sand by water.

  In order to increase the sieving effect, it is preferable to vibrate the sieving device. For example, it is preferable to vibrate in a direction perpendicular to the jet direction of the high-pressure water jet at a frequency of about 1 to 10 hertz.

  Further, the method for classifying aggregate sand according to the present invention is a method for classifying aggregate sand using a wet classifier and a fine sand collecting device for classifying aggregate sand. Aggregate sand discharged at high pressure from a pipeline transported by a water jet is classified with a wet classifier, and an inclined plate inclined downward so as to reach the opening of the side wall from directly below the water surface is installed in the fine sand recovery device. A fine diameter aggregate sand discharged together with water from the wet classifier is introduced into the region on the inclined plate, and a spray provided in the vicinity of the baffle plate installed in the vertical direction of the region on the inclined plate. By discharging water from the device, a circulatory flow is caused to float the small-diameter aggregate sand to the water surface together with the water, and the floated small-diameter aggregate sand descends onto the inclined plate along the baffle plate. Discharged from the spray device toward the side wall opening of the fine sand recovery device. It is characterized by supplying to the conveying pipe of the sand for aggregate sand aggregate for a minute diameter on the inclined plate through an opening provided in the side wall of the fine sand reclamation device by the pressure of that water.

The water pressure discharged from the spray device may be a pressure that causes a circulating flow that floats fine aggregate sand together with water to near the surface of the water, and is preferably 0.01 kg / cm ² or more. . However, if the pressure of the spray water is too strong, turbulent flow may occur and the inclined plate may be damaged. Therefore, the pressure is preferably 1.0 kg / cm ² or less, and 0.02 kg / cm. More preferably, it is ^{2 to} 0.5 kg / cm ² .

  The material of the baffle plate is not particularly limited, and any material can be used as long as it has a function of resisting the flow of the floated fine-diameter aggregate sand.

  Examples of the present invention will be described below. However, the present invention is not limited to the following examples, and can be appropriately changed and modified without departing from the technical scope of the present invention.

  FIG. 1 is an overall view of a sand cleaning and classification system including the aggregate sand classification apparatus of the present invention. Reference numeral 1 denotes a conveyor for conveying sand, gravel, crushed stone, crushed sand or the like collected in a mountain or river. Reference numeral 2 denotes a hopper for feeding sand or the like conveyed by the conveyor 1. Reference numeral 3 denotes an aggregate sand cleaning apparatus described later. 4 is a pumping pipe for pumping a mixture of sand and washing water, and reaches the inlet of the wet classifier 5.

  FIG. 2 is an enlarged view showing the vicinity of the inlet of the wet classifier 5. In FIG. 2, reference numeral 6 denotes a charging pipe for discharging sand with a high-pressure water jet, and the pressure feeding pipe 4 is connected to the charging pipe 6. 7 is a first sieve having a large sieve opening (5.00 mm in this embodiment), and 8 is a second sieve having a small sieve opening (0.15 mm in this embodiment). Sand between the first sieve 7 and the second sieve 8 (having a particle size in the range of 0.15 mm to 5.00 mm) falls on the conveyor 9. In addition, it is possible to use various sieves according to the purpose of classification, and as shown in 9a, 9b, 9c, 9d, and 9e, a plurality of sieve openings having different sizes are provided. The sieves can be used by appropriately replacing them (when the first sieve 7 and the second sieve 8 are actually used, these sieves 9a to 9e are arranged on the machine side and are in a standby state). For example, the sieve 9a has a sieve opening of 4.00 mm, the sieve 9c has a sieve opening of 1.00 mm, and sand having a particle size in the range of 1.00 mm to 4.00 mm is to be sieved. In this case, these two sieves 9 a and 9 c are incorporated in the wet classifier 5 in place of the first sieve 7 and the second sieve 8.

  Reference numeral 10 denotes a screw conveyor which scoops up the aggregate sand (in this embodiment, a particle size exceeding 5.00 mm) staying on the first sieve 7 and passes through the pipe 11 to the other weight by the weight of the sand. Transfer to place. Other types of conveyors can be used as long as they have a function capable of scooping up sand having the above particle diameter. The transferred sand is further classified if necessary, and then provided for a predetermined purpose. Reference numeral 10 a denotes a drive motor for the screw conveyor 10. In addition, most of the things smaller than the sieve opening of the second sieve 8 (having a particle diameter of less than 0.15 mm) do not fall on the conveyor 9 and are shown by arrows 12 (see FIG. 1). ), Drops toward the bottom of the wet classifier 5, but a part of the fine sand having a particle size of less than 0.15 mm falls on the transport conveyor 9 along with the sand having a particle size of 0.15 mm or more. To do.

  As shown in FIG. 1, the conveyor 9 includes a first pulley 13 (driven side) immediately below the first sieve 7 and the second sieve 8 and a second pulley 14 (drive side) positioned above the first pulley 13. ) In a circulating manner.

Reference numeral 15 denotes an air blower, and high-pressure air (pressure of about 0.01 to 1.00 kg / cm ² ) discharged from the air blower 15 is conveyed from a plurality of nozzles 16 provided in the vicinity of the wall surface of the wet classifier 5. Sprayed toward the aggregate sand on the conveyor 9.

  Reference numeral 17 denotes a water level indicating controller for instructing the water level in the wet classifier 5 and adjusting the water level.

  A discharge port 18 is provided in the lower part of the wet classifier 5 in order to discharge the aggregate sand separated from the conveyor 9 that circulates along the second pulley 14 to the outside of the wet classifier. The sand discharged from the discharge port 18 is transported to another place by the conveyor 19, and after necessary processing is performed, it is used as an aggregate component.

  A fine sand collecting device 20 is disposed below the wet classifier 5, and the fine-diameter aggregate sand accumulated on the bottom of the wet classifier 5 so as to reach the fine sand collecting device 20 from the bottom of the wet classifier 5. A slurry discharge pipe 21 for discharging slurry consisting of water and water is formed, and a screw conveyor 22 for scraping mud staying at the bottom of the fine sand recovery device 20 is attached to the fine sand recovery device 20. . The mud scraped up by the screw conveyor 22 is transported to another place by the conveyor 23, subjected to a treatment such as drying, and then provided for a predetermined purpose. It should be noted that other types of conveyors can be used as long as they have a function capable of scraping mud. Reference numeral 22 a denotes a drive motor for the screw conveyor 22.

  FIG. 3 is an enlarged view of a side surface including a cross section of a main part of the fine sand collection device 20. An opening 24 is provided in the side wall of the fine sand collecting device 20, and an inclined plate 25 that is inclined downward so as to reach the opening 24 from directly below the water surface L is installed. Baffle plates 26a, 26b, and 26c are installed in the vertical direction of the slurry area composed of the fine-diameter aggregate sand and water on the inclined plate 25. Further, spray devices 27, 28 and 29 for discharging water toward the opening 24 are installed. The opening 24 is connected to a pipe line 30 that leads to the hopper 2 into which sand or the like conveyed by the conveyor 1 is introduced. A water level adjusting plate 31 adjusts the water level of the slurry.

  FIG. 4 is a plan view of FIG. As shown in FIG. 4, the spray device 27 includes a spray header 27a and a plurality of spray nozzles 27b, the spray device 28 includes a spray header 28a and a plurality of spray nozzles 28b, and the spray device 29 includes a spray header 29a and a plurality of spray headers 29a. Spray nozzle 29b. 32 and 33 are pipes for supplying water 34 (see FIG. 1) stored at the bottom of the fine sand collecting apparatus 20 to the spray headers 27a, 28a and 29a.

  FIG. 5A is a front view of the water level adjusting plate 31, and FIG. 5B is a front view of the end plate 34 that moves up and down while the water level adjusting plate 31 is in contact therewith. Two long holes 35 are formed in the water level adjusting plate 31. Bolts (not shown) are inserted into the bolt through holes 36 formed in the end plate 34 and the long holes 35 formed in the water level adjusting plate 31. The water level adjusting plate 31 is moved up and down by the length of the long hole 35 along the bolt, and the water level adjusting plate 31 is fixed by tightening the bolt with a nut (not shown) at a predetermined position, as shown by an arrow 37 in FIG. As described above, the amount of water that overflows from the slurry on the inclined plate 25 and flows out toward the stored water 34 at the bottom of the fine sand collecting device 20 can be adjusted.

  As shown in FIG. 1, a sedimentation tank 38 is disposed in the vicinity of the fine sand collection device 20. Supernatant water stored in the bottom of the fine sand collecting device 20 is supplied to the sedimentation tank 38 via the pipe 40 by the pump 39. The settling tank 38 is supplied with necessary makeup water as appropriate. The water in the sedimentation tank 38 is pumped by the pump 41 through the pipeline 42 as washing water for the aggregate sand washing apparatus 3.

  FIG. 6 is a cross-sectional view showing an example of the aggregate sand cleaning apparatus 3. The cleaning device 3 includes a carry-in pipe part 51, a straight pipe part 52, and a carry-out pipe part 53. The carry-in pipe part 51 has a large-diameter part 54 that is larger in diameter than the straight pipe part 52, and the end of the large-diameter part 54 is closed by a substantially semicircular lid body 55. The opening 56 is inserted in an airtight manner, and the injection port 56 injects the cleaning water W almost in the center of the straight pipe portion 52 in the same direction as the straight pipe portion 52. Branch pipes 57 and 58 are provided in the large diameter portion 54 in a direction intersecting the straight pipe portion 52 slightly on the carry-out side from the tip of the injection port 56, and the tip of the upward branch pipe 57 is put into the aggregate sand. Mouth. The downward branch pipe 58 is blocked by a water stop plate 59. The large-diameter portion 54 is connected to the straight pipe portion 52 via a tapered pipe 60, a short pipe portion 61 having the same diameter as the straight pipe portion 52, and flanges 62 and 63. The flanges 62 and 63 are connected to a fastening member such as a bolt and nut. The carrying-in pipe part 51 and the straight pipe part 52 are connected so that attachment or detachment is possible. The carry-out pipe part 53 has a T shape having a main pipe part 64 having the same diameter as the straight pipe part 51 and a branch pipe 65 branched in the crossing direction in the middle of the main pipe part 64, and flanges 66 and 67 are bolted. The unloading pipe part 53 and the straight pipe part 52 are detachably connected by being connected by a fastening member such as a nut. Further, the end portion of the main pipe portion 64 is closed with a water stop plate 68. The distal end of the branch pipe 65 is a discharge port 69.

  Next, the operation of the aggregate sand cleaning and classification system of the present invention configured as described above will be described.

In FIG. 1, aggregate sand such as crushed sand is introduced into the hopper 2 by the conveyor 1, and aggregate sand is continuously introduced into the conduit of the cleaning device 3 from the inlet 70 shown in FIG. 6. At the same time, the pump 41 of FIG. 1 is driven, and in FIG. 6, the cleaning water W is injected from the injection port 56 at a high pressure (about 150 kg / cm ² ). Then, the sand for aggregate collides with each other in the straight pipe portion 52 and collides with the inner surface of the straight pipe portion 52 to chamfer the aggregate sand and is washed. In this case, since there is a taper pipe 60 on the inlet side of the straight pipe portion 52, the flow of the aggregate sand and the washing water W is mixed and squeezed, and the subsequent washing and chamfering are performed well. Then, the mixture of the aggregate sand and the washing water W collides with the water stop plate 68, then changes its direction, and is discharged from the discharge port 69 in a state where the kinetic energy is slightly reduced by the collision, and the pressure feed pipe 4 of FIG. The inside is pumped and reaches the inlet of the wet classifier 5.

Since the pressure feeding pipe 4 is connected to the charging pipe 6 shown in FIG. 2, the aggregate sand is discharged into the wet classifier 5 along with the high-pressure water jet through the charging pipe 6. The pressure of the water jet at the time of charging is about 3 to 10 kg / cm ² . Among the thrown-in sand, those having a particle size exceeding 5 mm do not pass through the first sieve 7 and therefore stay on the first sieve 7. The large-diameter sand is lifted up by the screw conveyor 10 and transferred to another place through the pipe 11 due to its own weight. If necessary, the large-diameter sand is further classified and then provided for a predetermined purpose. Part of the sand having a particle diameter of 0.15 mm and 5.00 mm and a small diameter of less than 0.15 mm falls on the conveyor 9 from between the first sieve 7 and the second sieve 8. The remaining sand having a particle size of less than 0.15 mm passes through the second sieve 8 and reaches the bottom of the wet classifier 5.

  As shown in FIG. 1, the sand that has fallen on the transport conveyor 9 is slowly drained together with the transport conveyor 9 toward the second pulley 14 while being drained by the high-pressure air jetted from the nozzles 16. When it circulates along the second pulley 14, it is separated from the conveyor 9 near the top of the second pulley 14 and discharged from the discharge port 18. The discharged sand is conveyed to another place by the conveyor 19, and after necessary processing is performed, it is used as aggregate sand.

  The fine sand having a particle diameter of less than 0.15 mm that has passed through the second sieve 8 reaches the bottom of the wet classifier 5. The water level in the wet classifier 5 is adjusted by the water level indicating controller 17. When the water level reaches a certain level or more, the electric valve 71 is opened in response to a signal from the water level indicating controller 17, and the wet classifier 5 Slurry composed of small-diameter aggregate sand and water deposited on the bottom is supplied to the fine sand recovery device 20 via the slurry discharge pipe 21.

  As shown in FIG. 3, the fine sand collecting device 20 is provided with an inclined plate 25 that is inclined downward so as to reach the opening 24 from just below the water surface L, and has a small diameter discharged from the slurry discharge pipe 21. Slurry composed of aggregate sand and water is introduced into a region on the inclined plate 25. Since baffle plates 26a, 26b, 26c are installed in the vertical direction of the area on the inclined plate 25, and spray devices 27, 28, 29 for discharging water toward the opening 24 on the side wall are installed, As described in the above, it is possible to collect the fine aggregate sand.

  That is, as shown in FIG. 4, a vertical circulation flow is formed by water discharged from the spray nozzles 27b, 28b and 29b of the spray devices 27, 28 and 29, respectively. Although the minute diameter aggregate sand rises along the circulation flow, the present invention includes baffle plates 26a, 26b, and 26c that resist the smooth flow of the circulation flow. The aggregate sand having a diameter falls on the baffle plate and reaches the inclined plate 25 without being able to maintain the circulation flow because the baffle plate becomes a resistance. The small-diameter aggregate sand on the inclined plate 25 reaches the opening 24 by the pressure of water discharged from the spray nozzles 27 b, 28 b and 29 b, and is supplied to the hopper 2 through the pipe line 30. The fine sand is subjected to the same treatment in the cleaning device 3 and then supplied to the wet classifier 5 through the pressure feed pipe 4 and classified by the first sieve 7 and the second sieve 8. . Since the sieve of the first sieve 7 is 5.00 mm and the sieve of the second sieve 8 is 0.15 mm, only sand having a particle size of 0.15 to 5.00 mm falls on the conveyor 9. Actually, however, a part of the small-diameter sand having a particle diameter of less than 0.15 mm is accompanied by the sand having a particle diameter of 0.15 mm or more and falls onto the conveyor 9 and is discharged from the discharge port 18. Contained in the sand. The sand discharged from the discharge port 18 is conveyed to another place by the conveyor 19, and after necessary processing is performed, it can be used as aggregate sand.

  The fine aggregate sand having a particle diameter of less than 0.15 mm that has passed through the second sieve 8 and reached the bottom of the wet classifier 5 is subjected to the above-described action in the fine sand collecting device 20 and is again routed through the pipe line 30. After that, the fine sand having the small diameter is subjected to the same treatment in the cleaning device 3 and then supplied to the wet classifier 5 through the pressure feed pipe 4 and the fine particle having a particle diameter of less than 0.15 mm. Part of the diameter sand is recovered as aggregate sand as described above.

  By repeating such a classification cycle, the recovery rate of fine sand having a particle diameter of less than 0.15 mm can be improved. In order to further improve the recovery rate of the fine-diameter sand, the number of classification cycles may be increased. However, the recovery rate of the fine-diameter sand may not be improved by simply repeating the classification cycle. In addition, as described above, aggregate sand containing excessively small-diameter sand has the disadvantage that it cannot exhibit a predetermined strength as concrete, so the collection rate of fine-diameter sand should be adjusted appropriately. Is preferred. Therefore, as shown in FIG. 1, as shown by an arrow 37, a part of the slurry composed of the fine diameter sand and water on the inclined plate 25 is overflow water, and the stored water 34 at the bottom of the fine sand recovery device 20 is shown. By discharging toward the bottom, the recovery rate of fine sand having a particle diameter of less than 0.15 mm can be adjusted. This is because fine sand with a particle size of less than 0.15mm is basically low in weight and has low surface resistance, so it is easy to ride the flow of the circulation flow. Even if it abuts against the baffle plate, it will circulate in the slurry without falling even if it abuts against the baffle plate. Can do it.

  The water level adjusting plate adjusts the flow rate of the overflow water. As shown in FIG. 5, the water level adjusting plate 31 is inserted into a bolt through hole 36 formed in the end plate 34 and a long hole 35 formed in the water level adjusting plate 31, and a bolt (not shown) is inserted along the bolt. The water level adjusting plate 31 is moved up and down by the length of 35, and the water level adjusting plate 31 is fixed by tightening a bolt with a nut (not shown) at a predetermined position. As shown by an arrow 37 in FIG. The amount of water flowing out to the stored water 34 at the bottom of the fine sand collecting device 20 can be adjusted.

  At the bottom of the fine sand collecting device 20, a mud layer 72 is formed in which fine aggregate sand is concentrated. The mud is scraped up by the screw conveyor 22, dropped onto the conveyor 23 shown in FIG. 1, transported to another place, subjected to a treatment such as drying, and then used for a predetermined purpose.

  As shown in FIG. 1, a sedimentation tank 38 is disposed in the vicinity of the fine sand collection device 20, and the supernatant water 34 stored at the bottom of the fine sand collection device 20 is settled through a pipeline 40 by a pump 39. It is supplied to the tank 38. The settling tank 38 is supplied with necessary makeup water as appropriate. The water in the sedimentation tank 38 is pumped by the pump 41 through the pipeline 42 as washing water for the aggregate sand washing apparatus 3.

  Thus, according to the present invention, the closed system of water from the aggregate sand cleaning device 3 to the aggregate sand cleaning device 3 via the wet classifier 5, the fine sand collecting device 20, and the settling tank 38 is provided. Can be formed. With this system, the amount of washing water is gradually reduced by taking it out with sand or evaporating, so that clear water is supplied to the sedimentation tank 38 from a pipe (not shown) as needed. Is done.

<Example of collecting fine sand>
Next, the aggregated raw materials having the particle size distribution as shown in Table 1 or Table 2 are classified by the classifying device shown in FIG. Tables 3 and 4 show. Further, the product sand discharged from the discharge port 18 when the aggregate raw material having the particle size distribution as shown in Table 1 and Table 2 is not introduced into the fine sand collecting device 20 in the classification device shown in FIG. The particle size distributions are shown in Tables 5 and 6, respectively.

  The ratio of the aggregate raw material having a particle size of less than 0.15 mm is 12.9% in Table 1 and 5.6% in Table 2. Without the fine sand recovery device 20 of the present invention, most of these fine sands are discharged out of the system and cannot be recovered. As shown in Table 5 and Table 6, what is the ratio of fine sand with a particle size of less than 0.15 mm contained in the product sand when there is no fine sand recovery device? It is only 0.2 to 0.3%. However, by providing the fine sand collecting device as in the present invention, as shown in Tables 3 and 4, the ratio of the fine sand having a particle diameter of less than 0.15 mm contained in the product sand is 2.5%. 3.3%, and the recovery rate of fine sand can be improved.

1 is an overall view of a sand cleaning and classification system including an aggregate sand classification apparatus of the present invention. It is an enlarged view of the side including the cross section near the entrance of the wet classifier. It is an enlarged view of the side surface including the cross section of the principal part of a fine sand collection | recovery apparatus. FIG. 4 is a plan view of FIG. 3. FIG. 5A is a front view of a water level adjusting plate, and FIG. 5B is a front view of an end plate which is a counterpart to which the water level adjusting plate comes into contact and goes up and down. It is sectional drawing of a washing | cleaning apparatus. It is a schematic block diagram of the manufacturing apparatus of the conventional aggregate sand.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conveyor 2 ... Hopper 3 ... Aggregate sand washing apparatus 4 ... Pressure feeding pipe 5 ... Wet classifier 6 ... Input pipe 7 ... First sieve with large sieve opening 8 ... Second sieve with small sieve opening DESCRIPTION OF SYMBOLS 9 ... Conveyance conveyor 10 ... Screw conveyor 13 ... 1st pulley 14 ... 2nd pulley 15 ... Air blower 16 ... Nozzle 17 ... Water level indicator controller 18 ... Discharge port 19 ... Conveyor 20 ... Mud storage tank 21 ... Slurry discharge pipe 22 ... Screw conveyor 23 ... Conveyor 24 ... Opening 25 ... Inclined plate 26a, 26b, 26c ... Baffle plate 27, 28, 29 ... Spray device 27a, 28a, 29a ... Spray header 27b, 28b, 29b ... Spray nozzle 31 ... Water level adjustment Plate 34 ... End plate 35 ... Long hole 36 ... Bolt through hole 38 ... Precipitation tank 39 ... Pump 41 ... Pump 51 ... Carry-in pipe part 52 ... Straight pipe part DESCRIPTION OF SYMBOLS 3 ... Unloading pipe part 54 ... Large diameter part 55 ... Lid 56 ... Injection port 57 ... Branch pipe 58 ... Branch pipe 59 ... Water stop plate 60 ... Tapered pipe 61 ... Short pipe part 62 ... Flange 63 ... Flange 64 ... Main pipe Portion 65 ... Branch pipe 66 ... Flange 67 ... Flange 68 ... Water stop plate 69 ... Discharge port 70 ... Input port 71 ... Electric valve 72 ... Mud layer

Claims (4)

  A classifier for aggregate sand comprising a wet classifier for classifying aggregate sand and a fine sand collecting device, a pipeline for conveying aggregate sand by a high-pressure water jet, and the pipeline There is a wet classifier for wet-classifying aggregate sand discharged at a high pressure from a wet-type classifier, and a fine sand recovery device for recovering a small-diameter aggregate sand discharged together with water from the wet classifier An inclined plate that is placed directly under the wet classifier and tilts downward so as to reach the opening of the side wall from directly below the water surface of the fine sand recovery device, and a baffle plate is installed in the vertical direction of the area on the inclined plate A spray device for discharging water toward the side wall opening of the fine sand collecting device is installed in the vicinity of the baffle plate, and the fine-diameter aggregate sand discharged together with water from the wet classifier is used for the inclined plate. Introduced into the upper area, the opening provided in the side wall of the fine sand recovery device to the aggregate sand transport line Classifier sand for aggregate, characterized in that connection was.   2. The aggregate sand classification apparatus according to claim 1, wherein a water level adjusting plate for adjusting a flow rate of overflow water is installed at an end of a region on the inclined plate.   A method for classifying aggregate sand using a wet classifier and a fine sand collecting device for classifying aggregate sand, wherein the aggregate sand is discharged at high pressure from a pipeline carrying the high pressure water jet. Aggregate sand is classified with a wet classifier, and an inclined plate that is inclined downward so as to reach the opening of the side wall from directly below the water surface is installed in the fine sand collection device, and the fine diameter discharged from the wet classifier together with water The aggregate sand is introduced into the region on the inclined plate, and water is discharged from a spray device provided in the vicinity of the baffle plate installed in the vertical direction of the region on the inclined plate, thereby causing a circulatory flow and causing a minute flow. The aggregate sand with a diameter is floated with water to near the surface of the water, and the fine aggregate sand that has floated is lowered onto the inclined plate along the baffle plate, and the side wall opening of the fine sand collection device from the spray device Due to the pressure of water discharged toward Method for classifying the sand for aggregate, characterized in that the sand for aggregate from an opening provided in the side wall of the fine sand reclamation device for supplying the transport line of the sand for aggregate.   The method for classifying aggregate sand according to claim 3, wherein the flow rate of the overflow water is adjusted by a water level adjusting plate installed at an end of the region on the inclined plate.

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