JP2005205251A - Dredged sand classification system and equipment using pneumatic feeding system - Google Patents

Abstract

A dredged soil classification system that classifies dredged material dredged by a high concentration dredger, a grab dredger, etc. with a cyclone in the process of being pumped by pneumatic feeding.
The dredged soft mud-like earth and sand S is pneumatically fed, and the earth and sand plug S 'is repeatedly formed and collapsed in the earth and sand pressure feeding pipe 118, and the earth and sand plug S' which is pumped in a turbulent state is inverted cone-shaped. It introduce | transduces in the cyclone main body 125, and uses the centrifugal force resulting from the velocity energy, and the weight difference of a to-be-processed object, and carries out two-phase separation into the fine grain part b and the coarse grain part a. The lower end opening of the overflow discharge pipe 133 provided in the shaft core portion of the cyclone main body 125 is positioned in the region of the fine granule b, and the earth and sand in the region of the fine granule b is further subjected to pressure of high pressure air for sediment transport Is discharged from the overflow discharge pipe 133.
[Selection] Figure 1

Description

  The present invention relates to a dredged sand classification system and apparatus for classifying dredged sand dredged by a high-concentration dredger, a grab dredger or the like by a cyclone in a process of being pumped by pneumatic feeding.

  Conventionally, in order to maintain rivers and harbors, the sediment deposited in the channel and estuary has been dredged by dredgers, and the sediment has been landfilled and dumped into the ocean. Because it has disappeared and the ocean dumping of dredged soil has been regulated, securing a place to dump a large amount of dredged soil has become an urgent issue.

  On the other hand, there are places where beaches are eroded by coastal currents and sandy beaches retreat steadily toward the land, causing deterioration of the natural environment. Moreover, in a closed sea area closed by a seawall or the like, aerobic microorganisms multiply and consume a large amount of oxygen in the water and sludge layer, and there is a problem that fish and shellfish are killed.

  In recent years, in order to improve the water quality of dams, lakes, rivers, closed seas, or farms, sludge accumulated at the bottom has been actively modified and reduced in volume. (For example, refer to Patent Document 1).

  That is, as shown in FIG. 10, the bottom mud is continuously sucked from the dam 16 as the purification target water area by the suction pump 17 of the pump dredger 11 and fed to the vibrating fluid 12 through the bottom mud feed pipe 18. . The vibration fluid 12 receives the bottom mud sent from the pump dredger 11 by the bottom mud hopper 20, removes foreign matters such as sand, gravel, freewood and trash from the bottom mud, and discharges the mud to the muddy water tank. Store in 21. Then, the muddy water stored in the muddy water tank 21 is supplied to the three-phase cyclone 13 through the muddy water supply pipe 23 by the pump 22.

  In the three-phase cyclone 13, the muddy water flowing into each cylindrical container 24 generates a strong swirl flow inside, and particles having a large particle size are blown to the side wall and separated by centrifugal separation. A large number of particles having a small particle size that cannot be separated due to the function are liberated, and pressurized water is introduced therein to generate a large number of microbubbles, and fine particle particles, organic components, and the like adhere thereto.

  The particles having a large particle diameter that have been centrifuged on the wall surface fall along the wall surface by gravity and are discharged to the sand removal tank 26, while the fine particle particles and organic components rise upward due to the attached micro bubbles. Then, it flows out into the cylindrical collecting container 25. In addition, the cylindrical collection container 25 separates the large particles, which could not be reliably separated by centrifugation, into a slurry stock solution containing fine particle soils, organic components, and microbubbles, and the large particles are discharged into the sand. The slurry stock solution is supplied to the tank 26 to the self filter 14. That is, in the three-phase cyclone 13, the mud is classified into a gravel having a particle size larger than a predetermined particle size (0.075 mm) and a slurry stock solution containing silt or organic matter having a particle size equal to or smaller than a predetermined particle size by centrifugal force separation.

  In this waste sand tank 26, the supernatant water accumulated inside is transferred to the slurry stock solution discharge pipe 33, thereby containing large gravel (sand gravel having a particle size larger than 0.075 mm) discharged from the waste sand tank 26. The amount of water is adjusted to about 50%. The large gravel discharged from the sand discharge tank 26 is returned to the river downstream of the dam 16 by a truck (not shown).

  On the other hand, the slurry stock solution supplied to the self-filter 14 is injected with a flocculant into the slurry stock solution by the flocculant injection device 51 on the way, and stirred by the mixer 55, so that the suspended substances in the slurry stock solution are mutually exchanged. Promotes agglomeration. In the self-filter 14, when the slurry stock solution flows into the treatment tank 41 as an upward flow from each stock solution supply nozzle 46, a part of the suspended substance in the slurry stock solution rising in the treatment tank 41 is settled and processed. A concentrated slurry layer having a high concentration of suspended solids is formed in the lower region in the tank 41, and the supernatant liquid is extremely clarified by passing the slurry stock solution from each stock solution supply nozzle 46 through the concentrated slurry layer. (Turbidity is 20 ppm or less) rises in the treatment tank 41, is discharged from the supernatant discharge port 42, and is returned to the dam 16 by the feeding pipe 15.

  On the other hand, a sedimented slurry layer is formed on the bottom of the processing tank 41 by sedimentation and deposition of suspended substances in the slurry stock solution, and the deposited slurry (moisture content of 85% or less) is discharged by the deposited slurry discharge unit 47. The

In this case, the accumulated slurry is continuously or periodically discharged by the accumulated slurry discharge unit 47 and is sent to the dewatered sludge hopper 64 via the discharge pipe 61 and the sludge pump 62. It is transported to the reprocessing plant. In the reprocessing plant, the dehydrated sludge can be reused by applying organic matter removal treatment or solidification treatment. In this case, the organic matter removal treatment method includes incineration, high-temperature aerobic fermentation, composting after fractionation by specific gravity difference, and the like. Moreover, as a utilization method after performing a solidification process, there are a landfill material and a concrete aggregate, and it can also be discharged into a river.
Japanese Patent Laid-Open No. 2001-20318 (page 7-8, FIG. 1)

However, the invention of Patent Document 1 has the following problems. That is,
(A) In the invention of Patent Document 1, the bottom mud fed from the pump dredger 11 removes foreign matters such as sand, gravel, freewood, and garbage from the vibration sieve 12 and the mud is once stored in the mud tank 21. . And since the muddy water stored in the muddy water tank 21 is supplied to the cyclone 13 via the muddy water supply pipe 23 by the pump 22, not only the muddy water tank 21 for storing muddy water but also the muddy water is supplied. Since the muddy water pump 22 is required, there is a problem that the equipment cost increases accordingly.

  (B) On the other hand, earth and sand in the vicinity of the estuary and in the closed sea area that are subject to classification have a relatively large amount of sand. When soil with a relatively high sand content is made into sediment slurry and transported in a pipeline, the sand tends to separate and settle at the bottom of the pipeline during the pipeline transport. There is a risk of depositing on the bottom of the tube, leading to tube closure. Even when the pipe does not close, the concentration of the earth and sand slurry is irregular and greatly fluctuates, so that a stable classification effect cannot be obtained.

  For this reason, in the conventional cyclone-type earth and sand classifier, a sand tank is provided before the earth and sand slurry is put into the sand pump, and the earth and sand slurry is sufficiently stirred to prevent separation and settling of the sand and then put into the sand pump. ing. And in order to avoid the pipe | tube closure by sand sedimentation and sedimentation during conveyance, it has the discharge capability which produces the flow velocity which exceeds the deposition limit speed | rate of an input soil sand slurry at least. For this reason, the enlargement of the sand pump was inevitable.

  (C) Moreover, in order to improve the classification performance of earth and sand, it is necessary to reduce the slurry concentration of earth and sand. If necessary, it is necessary to add a large amount of water. However, in this case, since a large amount of residual water is generated after the classification treatment, the cost of water treatment for treating the residual water becomes large.

  The present invention has been made to solve such conventional problems, and the object of the present invention is to store mud mud fed at a high concentration from a dredger in a storage tank such as a mud tank. Therefore, the present invention is to provide a dredged sand classification method and apparatus using a pneumatic feeding system that is directly introduced into a cyclone type classifier by a pneumatic feeding system and classifies into gravel and silt clay with high efficiency.

  In order to solve the above-mentioned problems, the present invention according to claim 1 is configured to pneumatically feed dredged soft mud-like earth and sand, repeatedly form and collapse the earth-and-sand plug in the earth-and-sand feeding pipe, and be pumped in a turbulent state. The earth and sand plug is introduced into the inverted conical cyclone body, and the centrifugal force caused by the velocity energy and the weight difference between the objects to be processed are used to separate the two phases into fine and coarse particles. The lower end opening of the overflow discharge pipe provided in the shaft core part of the main body is positioned in the fine-grained area, and further, the overflow in the fine-grained area using the pressure of high-pressure air for sediment transport It is a dredged soil classification system using a pneumatic feeding system characterized by discharging from a discharge pipe.

  The present invention described in claim 2 is a dredged sand classification system using a pneumatic feeding system according to claim 1, wherein a water injection pipe is provided in the earth and sand pressure feeding pipe, while a cyclone type having the cyclone body and an overflow discharge pipe. Use of pneumatic feeding system characterized in that the coarse and fine fractions classified by the classifier are separated into solid and liquid, and a part of the supernatant water generated at that time is circulated and used for pouring into the water injection pipe. This is a dredged soil classification system.

  According to a third aspect of the present invention, there is provided an overflow discharge pipe in the shaft core portion of the inverted conical cyclone main body, and the earth and sand plug introduced into the cyclone main body is subjected to centrifugal force due to velocity energy and to-be-processed. In the cyclone type classifier that uses a weight difference of the product to separate into two phases into a fine particle and a coarse particle, the lower end opening of the overflow discharge pipe is located in the fine particle region, and A flow separator is provided at the lower end of the overflow discharge pipe, and the flow separator is provided so as to partially overlap the overflow discharge pipe, and for reversal provided with a gap at the bottom of the cylinder. It is the dredged soil classification apparatus characterized by comprising from the bottom part of this.

  The present invention according to claim 4 is characterized in that the cylindrical body of the flow separator provided at the lower end of the overflow discharge pipe is located at the boundary between the two-phase separated fine particles and coarse particles. 4. A dredged sand classification apparatus according to claim 3.

  In the present invention according to claim 5, the overflow discharge pipe is formed in a telescope shape, and the length is adjusted so that the lower opening of the overflow discharge pipe is located in a region of fine particles. The dredged soil classification apparatus according to claim 3.

  (A) As described above, the present invention according to claim 1 pneumatically feeds dredged soft mud-like earth and sand, repeatedly forms and collapses the earth-and-sand plug in the earth-and-sand feeding pipe, and is pumped in a turbulent state. The earth and sand plug is introduced into the inverted conical cyclone body, and the centrifugal force caused by the velocity energy and the weight difference between the objects to be processed are used to separate the two phases into fine and coarse particles. The lower end opening of the overflow discharge pipe provided in the shaft core part of the main body is positioned in the fine-grained area, and further, the overflow in the fine-grained area using the pressure of high-pressure air for sediment transport Discharge from the discharge pipe. By using these means, there is little risk of pipe closing due to sedimentation and accumulation of coarse particles (sand) in the middle of the sediment transport pipe, and the sediment can be transported at a stable slurry concentration. Stable classification can be performed in a cyclone classifier. In addition, due to the characteristics of pneumatic feeding, long distance transportation from a dredging point to a cyclone type classifying device, which is a classifying device, is possible with relatively little pressure loss.

  Further, in the present invention, the pneumatic feeding device conventionally used as the conveying means from the dredging point to the classification processing point is also used as the soil slurry injection means to the cyclone type classifying device as it is. Therefore, it is not necessary to separately prepare earth and sand slurry injection means such as a sand pump, and it is possible to suppress equipment costs and the like.

  In the cyclone classifier, earth and sand plugs are injected in the tangential direction of the cyclone, and heavy particles and large particles move toward the cyclone wall due to the strong centrifugal force generated at that time, and light and fine particles are near the center of the cyclone. Stop by. This effect can be used to easily classify coarse particles (sand) and fine particles (muddy water).

  If a pneumatic feeding system is used, the moving speed of the earth and sand plug produced | generated in the earth and sand pressure sending pipe with the compressed air for conveyance will become a high speed several times the mud water conveyance speed by the mud feeding pump shown by patent document 1. FIG. The higher the moving speed, the stronger centrifugal force is obtained and the higher classification effect is obtained. This is another advantage of using a pneumatic feeding system.

  (B) Further, in the present invention according to claim 2, coarse particles and fine particles classified by a cyclone classifier having a water injection pipe in the earth and sand pressure feeding pipe and having the cyclone main body and an overflow discharge pipe are provided. The liquid is separated into solid and liquid, and a part of the supernatant water generated at that time is circulated and used for water injection into the water injection pipe, so that the muddy water concentration at the time of earth and sand classification can be reduced and the remaining water is reduced. Therefore, it is possible to prevent an increase in wastewater treatment costs.

  (C) Further, the present invention according to claim 3 is provided with the overflow discharge pipe in the shaft core portion of the inverted conical cyclone main body, and the earth and sand plug introduced into the cyclone main body is caused by the velocity energy. In the cyclone type classifier that uses the centrifugal force and the weight difference between the workpieces to separate into two phases of fine and coarse particles, the lower end opening of the overflow discharge pipe is in the fine particle region. A cylinder having a flow separator at a lower end of the overflow discharge pipe, the flow separator being provided so as to partially overlap the overflow discharge pipe, and a gap at a lower portion of the cylinder. Therefore, the coarse particles once classified by the cyclone type classifier are prevented from moving again to the vicinity of the center due to fluctuations in the injection speed. The classifying effect has the effect of stabilizing.

  (D) Further, the present invention according to claim 4 is characterized in that the cylinder of the flow separator provided at the lower end of the overflow discharge pipe is positioned at the boundary between the two-phase separated fine particles and coarse particles. Therefore, mixing of the fine particles and the coarse particles can be avoided when discharging the fine particles, and only the fine particles can be efficiently discharged.

  (E) In the present invention according to claim 5, the overflow discharge pipe is formed in a telescope shape, and the length is adjusted so that the lower opening of the overflow discharge pipe is positioned in the region of fine particles. Therefore, when the fine particles are discharged, mixing of the fine particles and the coarse particles can be avoided, and only the fine particles can be discharged efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram for realizing a dredged soil classification system according to the present invention, and includes a pneumatic feeder 110 as a sediment transport means and a cyclone type classifier (hereinafter referred to as a soil cyclone) 111 as a classification means. And a sedimentation tank 112 as a solid-liquid separation means and a sand pit catchment basin 113.

  As shown in FIG. 2, the pneumatic feeding device 110 includes a horizontally long pressure-resistant tank 115 having a stirring device 114. An upper part of the pressure tank 115 is provided with a soil and sand injection hopper 116 for introducing bottom mud (earth and sand) S dredged by a grab dredger (not shown), and a high-pressure air introduction pipe 117 for introducing high-pressure air A. On the other hand, an earth-and-sand pressure feeding pipe 118 for delivering earth and sand S in the pressure-resistant tank 115 toward the soil cyclone 111 is provided below the pressure-resistant tank 115.

  The earth and sand charging hopper 116 includes a vibration fluid 119 at an upper opening end thereof and a valve 120 at a lower outlet portion. The earth and sand pressure feeding pipe 118 includes a valve 121 in the vicinity of the pressure tank 115. The stirring device 114 includes a horizontal rotating shaft 122 rotated by a motor (not shown) and a plurality of stirring blades 123 provided in a direction intersecting the horizontal rotating shaft 122. The high pressure air introduction pipe 117 is also provided with a valve 124.

  As shown in FIG. 3, the soil cyclone 111 includes an inverted conical cyclone main body 125, a telescopic inner cylinder 126, and a flow separator 127. And the coarse particle storage tank 128 is provided in the lower end part (underflow discharge pipe) 129 of the cyclone main body 125. Further, an overflow discharge pipe 133 is formed by the telescope-type inner cylinder 126 and a curved pipe portion 137 described later.

  The cyclone body 125 is formed in a so-called inverted conical shape that gradually decreases in diameter as it goes from top to bottom, and a telescoping inner cylinder 126 is provided on the center line (not shown). The telescope-type inner cylinder 126 is formed of a fixed cylinder 130 and a movable cylinder 131, and the upper end of the fixed cylinder 130 is provided in an airtight manner in an opening provided at the center of the deck 132 of the cyclone main body 125. Yes. The position of the lower opening of the movable cylinder 131 is appropriately adjusted according to the characteristics of the earth and sand. Specifically, it is positioned in the region for fine grains.

  The flow separator 127 is formed by a cylindrical side wall (tubular body) 134 and a bottom wall (bottom part) 135 for reversal. The reversing bottom wall 135 is formed in a Jinkasa shape, and is attached to a lower portion of a lifting / lowering rod 136 provided at the center of the telescopic inner cylinder 126. The elevating rod 136 is screwed into a female screw portion 138 provided in a curved pipe portion 137 connected to the telescope-type inner cylinder 126, and is moved up and down by rotating a handle 139. .

  On the other hand, the cylindrical side wall 134 is formed to have a predetermined diameter, and the movable cylinder 131 and the inversion bottom wall 135 are partially overlapped with the movable cylinder 131 by a plurality of support plates 140 arranged radially. Is attached. More specifically, it is important that the cylindrical side wall 134 is located at the boundary between the coarse particles and the fine particles.

  In addition, the earth and sand introduction pipe 141 is attached to the side surface of the cyclone main body 125 in the tangential direction of the cyclone main body 125. In addition, a bowl-shaped coarse particle storage tank 128 for temporarily storing the classified coarse particles is provided at the lower portion of the cyclone main body 125. In this storage tank coarse particle storage tank 128, a coarse particle discharge pipe 142 is inserted.

  A separately prepared soil cyclone 111 is connected to the overflow discharge pipe 133 of the soil cyclone 111, and a high-pressure aerodynamic force for sediment transport can be used to classify the system into several stages. According to this method, a higher classification effect can be obtained.

  As shown in FIG. 4, the sedimentation tank 112 is formed in a cyclone shape similar to the already-described soil cyclone 111, and the inverted conical sedimentation tank body 145 is provided with a muddy water injection pipe 146 in the tangential direction, Fine particles (muddy water) b classified by the soil cyclone 125 are introduced.

  In the center of the sedimentation tank main body 145, bottomed flow straightening tubes 147 and 148 formed by a perforated plate are provided in a double manner. These rectifying cylinders 147 and 148 are provided on the lower surface of the deck 149 of the main body 145. Note that the upper portion of the small-diameter rectifying cylinder 148 is an opening. A covered exhaust tube 150 is provided on the upper surface of the deck 149, and a plurality of exhaust ports 151 are provided on the side surface thereof. Further, the sedimentation tank main body 145 is provided with a siphon-type drain pipe 152 at the center of a small-diameter rectifying cylinder 148 so that the supernatant water w in the sedimentation tank main body 145 is drained.

  Furthermore, the lower end portion of the settling tank main body 145 is provided with a soil discharge pipe 153 that discharges fine particles (silt / clay) n precipitated in the lower portion of the settling tank main body 145. The valve 154 of the earth discharge pipe 153 is composed of a bowl-shaped flexible valve membrane 155 provided in the earth discharge pipe 153 and a spherical valve body 156, and the spherical valve body 156 is advanced to advance the bowl-shaped valve body 156. By pressing the valve membrane 155 against the inner surface of the soil discharge pipe 153, the soil discharge pipe 153 is closed, and by retreating the spherical valve body 156, the soil discharge pipe 153 is opened.

  Here, the valve membrane only needs to have flexibility and wear resistance, and examples thereof include a rubber product and a fabric product coated with rubber.

  As shown in FIG. 5, the sand pit catchment pit 113 has a box-shaped pit 158 partitioned by a partition weir 159, and the sand catcher 160 has a coarse particle fraction a classified by the soul cyclone 111 a. The drainage pipe 163 for discharging the supernatant water w is provided in the catchment basin 162.

  Returning to FIG. 1, a water injection pipe 164 is provided in the middle of the earth and sand pressure feeding pipe 118 that communicates the pneumatic feeding device 110 and the soil cyclone 111. A sewage circulation pipe 165 is connected to the water injection pipe 164 so that a part of the supernatant water w, that is, the sewage w ′, is supplied to the settling tank 112 and the sand pit collecting tank 113. Drainage pipes 152 and 163 of the sedimentation tank 112 and the sand pit collecting tank 113 are connected to the remaining water circulation pipe 165. The remainder of the supernatant water w is finally treated by the water treatment device 167 and then discharged out of the system. Excess supernatant water w is supplied to the water treatment device 167 via a pipe 168 connected to the spill water circulation pipe 165.

  Next, a method for treating bottom soil (earth and sand) dredged by a grab dredger (not shown) will be described.

  As shown in FIG. 2, when soil (sand) S dredged by a grab dredger (not shown) is put on the vibration sieve 119, a large foreign substance such as a free tree or garbage or a large gravel (Fig. The earth and sand S from which (not shown) has been removed flows into the pressure tank 115 through the earth and sand injection hopper 116. The earth and sand S that has flowed into the pressure tank 115 is agitated by the agitating device 114 to become a liquid phase, and becomes an earth and sand slurry.

  When a predetermined amount of earth and sand S is introduced into the pressure tank 115, the valve 120 of the earth and sand injection hopper 116 is closed, and the valve 124 of the high pressure air supply pipe 117 is opened, and then the high pressure air A is introduced into the pressure tank 115 from the high pressure air supply pipe 117. Flows in and the pressure in the pressure tank 115 increases. When the valve 121 of the sediment pressure feeding pipe 118 is opened when the pressure in the pressure resistant tank 115 reaches a constant pressure, the sediment slurry in the pressure resistant tank 115 is pushed out into the sediment pressure feeding pipe 118 and is pumped toward the soil cyclone 111.

  As shown in FIG. 6, the earth and sand slurry is a plug flow in the earth and sand pressure feeding pipe 118, that is, a flow in which the liquid phase portion (earth and sand plug) S ′ and the gas phase portion A ′ flow alternately, that is, a two-phase flow. Form and move. In front of the earth and sand plug S ', a spiral wave-like vortex (not shown) is generated, and the earth and sand in front of the earth and sand plug S' is taken in and moved forward while stirring. Since the earth and sand plug S 'in the earth and sand pressure feeding pipe 118 moves to the end of the earth and sand pressure feeding pipe 118 while being constantly stirred and mixed, it not only has an effect of preventing the separation of sand, but also has an effect of stabilizing the slurry concentration. The plug flow develops as the sediment flow distance (conveyance distance) increases and is injected into the soil cyclone 111 of the sediment transport pipe 118 at a high speed.

  As shown in FIG. 7, the liquid phase component (sediment plug) S ′ that has flowed into the soil cyclone 111 at a high speed generates centrifugal force while descending while drawing a spiral along the inverted conical cyclone body 125. The coarse particle portion (sand) a in the liquid phase portion (earth and sand plug) S ′ approaches the wall surface of the cyclone main body 125 and slowly descends along the wall surface.

  On the other hand, the fine particles (muddy water) b is pushed to the center of the cyclone main body 125. For this reason, the coarse part (sand) a increases in the lower part of the cyclone main body 125, and the fine part (muddy water) b accumulates in the upper part. An inner cylinder (overflow discharge pipe) 126 provided at the center of the cyclone main body 125 serves to prevent a short path of the liquid phase component (sand plug) S ′ and the gas phase component A ′ flowing into the cyclone main body 125. Yes.

  When the sediment level in the cyclone main body 125 rises due to intermittent inflow of the liquid phase part (sediment plug) S ′, and the lower opening of the inner cylinder (overflow discharge pipe) 126 is blocked by the muddy water b, it is shown in FIG. Thus, the muddy water b is discharged from the inner cylinder (overflow discharge pipe) 126 by the air pressure. The flow separator 127 has a function of preventing the classified coarse particle (sand) a from moving again due to the pulsation of the earth and sand plug S ′.

  On the other hand, when a measuring device (not shown) senses that the coarse particles are stored in the coarse particle storage tank 128, a pump (not shown) is driven to deposit the coarse particles (sand) accumulated in the granular storage tank 128. a is discharged from the discharge pipe 142 (see FIG. 9).

  As shown in FIG. 4, the muddy water b supplied from the inner cylinder (overflow discharge pipe) 126 of the soil cyclone 111 is solid-liquid separated in the sedimentation tank 112, and fine particles (silt / clay) n are in the lower part of the sedimentation tank 112. The supernatant water w accumulates on it. The supernatant water w is discharged from a siphon drainage pipe 152. Fine particles (silt / clay) n precipitated in the lower part of the settling tank 112 are taken out by appropriately operating the valve 154 and then dumped, for example, in a final disposal site (not shown).

  On the other hand, as shown in FIG. 5, the coarse particle portion (sand) a supplied from the coarse particle storage tank 128 is stored in the sand collecting basin 160 of the sand stop pit water collecting basin 113. At that time, the supernatant water w on the coarse particle portion (sand) a flows over the partition wall 159 to the adjacent water collection side 162 and is drained from the drain pipe 163. The sand a in the sand collecting trough 160 is taken out by a civil engineering machine such as a backhoe, and then replenished to a lost beach, for example.

  Referring back to FIG. 1 again, a part (surplus water) w ′ of the supernatant water w discharged from the settling tank 112 and the sand retention pit water collecting tank 113 is supplied to the water injection pipe 164 through the residual water circulation pipe 165. Is done. The residual water w 'introduced from the water injection pipe 164 into the earth and sand pressure feeding pipe 118 is stirred with the earth and sand plug S' in the earth and sand pressure feeding pipe 118, and the slurry concentration of the earth and sand plug S 'decreases. For this reason, classification of coarse fraction (sand) a and fine fraction (muddy water) b is further improved in the soil cyclone 111.

  As already explained, the remainder of the supernatant water w is finally treated by the water treatment device 164 and then discharged. In the present invention, a part of the supernatant water w (surplus water) is circulated and used. Therefore, the processing amount of the supernatant water w to be finally processed by the water treatment device 164 can be reduced.

It is a schematic block diagram for implement | achieving the dredged material classification system which concerns on this invention. It is sectional drawing of a pneumatic feeder. It is sectional drawing of a soil cyclone. It is sectional drawing of a sedimentation tank (example). It is sectional drawing of a sand stop pit catchment basin (example). It is explanatory drawing of a sediment plug. It is explanatory drawing which shows a mode that an earth-and-sand plug is classified into a coarse particle part (sand) and a fine particle part (muddy water) with a soil cyclone. It is explanatory drawing which shows a mode that a fine particle part (muddy water) is discharged | emitted from an overflow discharge pipe using an air pressure. It is explanatory drawing which shows a mode that a coarse particle part (sand) is taken out from the coarse particle storage tank in the lower part of a soil cyclone. It is a schematic block diagram of the conventional water purification system.

Explanation of symbols

a Coarse grain b Fine grain S Sediment S 'Sediment plug 111 Cyclone classifier 118 Sediment pressure feeding pipe 128 Reservoir 138 Discharge port with inner cylinder

Claims (5)

The dredged soft mud-like sediment is pneumatically fed, and the formation and collapse of the sediment plug is repeated in the sediment delivery pipe, and the sediment plug that is pumped in turbulent flow is introduced into the inverted conical cyclone body, and the velocity energy is The resulting centrifugal force and the weight difference between the workpieces are used for two-phase separation into fine and coarse particles, and the lower end opening of the overflow discharge pipe provided in the shaft core of the cyclone body is finely divided. In addition, the sand and sand classification using the pneumatic feeding system is characterized in that the fine sand and sand are discharged from the overflow discharge pipe using the pressure of the high-pressure air for sediment pressure feeding. system. In the dredged soil classification system using the pneumatic feeding system according to claim 1, a coarse particle fraction classified by a cyclone type classification device provided with a water injection pipe in the sediment pressure feeding pipe and having the cyclone main body and an overflow discharge pipe is provided. A fine sand classification system using a pneumatic feeding system, wherein fine particles are separated into solid and liquid, and a part of the supernatant water generated at that time is circulated and used for water injection into the water injection pipe. In addition to having an overflow discharge pipe at the shaft core of the inverted cone cyclone body, the earth and sand plug introduced into the cyclone body is fine-grained using the centrifugal force due to its velocity energy and the weight difference between the objects to be processed. In a cyclone classifier that is separated into two phases into a fine particle and a coarse particle, the lower end opening of the overflow discharge pipe is positioned in the fine particle area, and a flow separator is provided at the lower end of the overflow discharge pipe. And the flow separator is composed of a cylinder provided so as to partially overlap the overflow discharge pipe, and a reversing bottom provided with a gap in the lower part of the cylinder. Dredged soil classification equipment. 4. The dredged sand classification apparatus according to claim 3, wherein a cylinder of a flow separator provided at a lower end portion of the overflow discharge pipe is positioned at a boundary between a fine particle portion and a coarse particle portion separated in two phases. 4. The bag according to claim 3, wherein the overflow discharge pipe is formed in a telescope shape, and the length is adjusted so that a lower opening of the overflow discharge pipe is located in a region of fine particles. Sediment classification equipment.

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