JP2005111383A - Sand collecting tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sand collecting tank which is provided with sand collectors which can be easily checked and repaired, and is capable of efficiently collecting accumulated sand. <P>SOLUTION: This sand collecting tank is provided with a water tank 1 having an inlet port 17 and outlet port 19 of water and a plurality of the sand collectors 2 disposed on the bottom part of the water tank. The sand collectors 2 are arranged so that the distance from the bottom part successively increases upward from the inlet port side to the outlet port side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sand collecting tank that is installed in a water treatment plant for treating purified water, sewage, waste water, and the like and is capable of collecting sand accumulated therein.

  As one of the conventional sand collecting tanks of this kind, there is a sand transport device in a sand basin. In this apparatus, a plurality of sand collection tanks (sedimentation basins) provided in the water treatment plant are covered with a slab at the top, and a wall of the sand collection tank is located at an intermediate position between the slab and the bottom of the sand collection tank. A pedestal continuous with the part is formed, and a pipe line connected to a fluid feeding device such as a pump is fixedly disposed on the pedestal. A branch pipe is branched from the pipe, and the branch pipe is suspended along the wall of the sand collecting tank, bent in the vicinity of the bottom, and plurally in a direction substantially orthogonal to the water flow direction on the bottom. It is arranged. In each of the plurality of branched pipes arranged, a plurality of injection nozzles are arranged at predetermined intervals in the water flow direction, and are sent from a pump and fed through the pipes and the branch pipes. It is possible to inject the pressure water to be directed toward the downstream side substantially parallel to the water flow direction (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 63-62508 (the second page, upper right column, the bottom row to the lower right column, the first row, and FIGS. 1 and 2)

  In the above sand collecting tank, since the spray nozzle is fixed to the bottom, there is a drawback that the spray nozzle becomes an obstacle when collecting the accumulated sand in one place. Also, in order to collect the accumulated sand evenly, it is necessary to install a large number of injection nozzles, which increases the equipment cost and increases the amount of inspection and repairs such as clogging of the injection nozzles. There were also disadvantages.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain a sand collecting tank capable of efficiently collecting collected sand while preventing clogging of the injection nozzle. It is.

The sand collecting tank according to the present invention includes a water tank having a water inlet and an outlet, and a sand collecting tank provided with a plurality of sand collecting devices at the bottom of the water tank, wherein the sand collecting device is connected to the outlet from the inlet side. The distance from the bottom is gradually increased to the upper side.
In addition, a boundary structure is provided between the sand collecting devices installed in two or more rows toward the outflow port.

According to the present invention, the sand collecting device increases the distance from the bottom to the top from the inlet side to the outlet side, so that the spray nozzle is not buried in the sand. Therefore, clogging of the injection nozzle can be prevented, and accumulated sand can be collected efficiently.
Moreover, sand can be efficiently collected by providing the boundary structure between the sand collecting devices installed in two or more rows toward the outlet.

  FIG. 1 is a partial horizontal sectional view of a water tank 1 and a sand collecting device 2 in an embodiment for carrying out the present invention, FIG. 2 is a partial vertical sectional view thereof, and FIG. 3 is a transverse sectional view thereof. The water tank 1 in this embodiment is sometimes called a sedimentation basin, a mud collection tank, or a sand sedimentation basin, and indicates a tank or a groove in which sand easily accumulates. The aquarium 1 accommodates raw water such as purified water, sewage and wastewater, and precipitates sand in the raw water. Although it does not necessarily limit, in this embodiment, the external shape of the water tank 1 is made into a substantially rectangular parallelepiped, and the cross section is made into the shape symmetrical left and right toward a water flow direction. Therefore, in the following description, portions or members at symmetrical positions are indicated by the same reference numerals.

  The aquarium 1 includes a horizontally installed bottom 11, left and right side walls 12 erected on both side edges of the bottom 11, front walls 13 connecting the bottom 11 and the front ends of the side walls 12, and the bottom 11 and both sides. The rear wall 14 is connected to the rear end of the wall 12. A partition wall 15 is provided in the middle of the tank body 1 in the width direction, and the interior of the water tank 1 is divided into two chambers 16. The front wall 13 is provided with an inlet 17 for raw water. A wall opening 18 is provided at the rear end of the partition wall 15 so that both chambers 16 communicate with each other. A water and sand outlet 19 is provided on the rear wall 14 with respect to the left chamber 16 in the direction of water flow. Needless to say, the water tank 1 is provided with support means (not shown) for supporting the sand collecting device 2.

  As is most apparent in FIG. 3, a boundary structure 20 that protrudes upward from the upper surface 11 a of the bottom 11 is provided in the middle of the left and right of each chamber 16. The cross section of the boundary structure 20 has a low mountain shape symmetrical to the left and right, and is formed by left and right inclined surfaces 20a and a central horizontal surface 20b. An inclined surface 11 b is provided at the intersection of the bottom 11 and the side wall 12, and an inclined surface 11 c is provided at the intersection of the bottom 11 and the partition wall 15. Therefore, each chamber 16 is provided with the upper surface 11a, the inclined surface 11b and the inclined surface 20a, or two grooves 21 each including the upper surface 11a, the inclined surface 11c and the inclined surface 20a. These grooves 21 are terminated before reaching the rear wall 14 as is apparent from FIG. The reason is that the sand accumulated in each groove 21 flows toward the outlet 19 as will be described in detail later.

  2 and FIG. 3, a plurality of sand collecting devices 2 are installed in each groove 21, a pipe line 32 that guides washing water to these sand collecting apparatuses 2, and a washing method that pumps water to the pipe line 32. A water pump 33 is used. The pipe line 32 includes two main pipe lines 32a that extend substantially horizontally in the upper part of each chamber 16, a plurality of upper branch pipe lines 32b that branch from each main pipe line 32a and extend downward, and these upper branch pipe lines 32b. The sand collecting device 2 is provided at the lower end of the lower branch circuit 32c. In addition to the cleaning water pump 33, the pipe 32 is provided with a cleaning water valve, a flow meter and the like (not shown), and the sand collecting device 2 controls the cleaning water pump 33, the cleaning water valve and the like (not shown). Means are provided.

  4 is a plan view of the sand collecting device 2, and FIG. 5 is a cross-sectional view taken along line AA of FIG. The sand collecting device 2 can be disassembled, and the height can be adjusted by the support mechanism 34. The sand collecting device 2 includes a water conduit 41 that guides water from the lower branch conduit 32c, an injection nozzle 42 that injects water from the water conduit 41, and a mixing tube 43 that mixes air into the water from the injection nozzle 42, The intermediate flange 42 a is provided integrally with the injection nozzle 42. In the sand collecting device 2, a packing 44 that seals between the water conduit 41, the spray nozzle 42 and the mixing tube 43, and a plurality of bolts 45 that connect the water conduit 41, the spray nozzle 42, the mixing tube 43 and the packing 44. And a nut 46 are also included. Although it does not necessarily limit, SUS304 can be used for the material of the water conduit | pipe 41, the injection nozzle 42, and the mixing pipe | tube 43. FIG.

  Here, as is most apparent in FIG. 1, for example, ten sand collecting devices 2 are arranged in the four grooves 21. Further, for example, seven sand collecting devices 2 are arranged before and after the wall opening 18. Ten sand collecting devices 2 in the groove 21 are linearly arranged at substantially equal intervals, and the remaining seven sand collecting devices 2 are suitable for flowing sand from each groove 21 toward the outlet 19. Arranged at intervals and orientations. And, as is most apparent in FIG. 5, the distance between the spray nozzle 42 of the sand collecting device 2 and the bottom 11 of the water tank 1 is gradually increased upward by 25 mm, for example, in the water flow direction. In addition, although the installation distance from the bottom face of the sand collecting apparatus 2 was changed upward by 25 mm, it is not limited to 25 mm, but the installation distance can be changed depending on the situation such as the sand removal amount and the sand accumulation amount.

  The sand collecting device 2 will be further described. At the base end portion of the water conduit 41, a flange 41a for connecting to the lower branch conduit 32c is provided. A flange 41 b for connecting the injection nozzle 42 and the mixing pipe 43 is provided at the end of the water conduit 41. An intermediate flange 42 a is provided integrally with the injection nozzle 42. The mixing pipe 43 includes a pipe main body 43a extending in the traveling direction of the water jetted from the jet nozzle 42, and an air introduction pipe 43b connected to the pipe main body 43a from the lateral direction. A flange 43c for connecting the water conduit 41 and the mixing tube 43 is provided at the proximal end of the tube body 43a. A socket 43d is provided at the upper end of the air introduction pipe 43b. Therefore, when the sand collecting device 2 is assembled, the packing 44 is disposed between the flange 41b, the intermediate flange 42a, and the flange 43c, and the flange 41b, the intermediate flange 42a, and the flange 43c are tightened by the bolt 45 and the nut 46. That's fine. The flange 41b and the flange 43c may be integrally formed with the water conduit 41 and the mixing tube 43, respectively.

  On the other hand, the support mechanism 34 includes a base plate 51 that can be fixed to the bottom 11 of the tank body 1, a lower pipe 52 erected on the base plate 51, and an upper pipe 53 fitted into the lower pipe 52 from above. is there. The upper end of the upper pipe 53 is fixed to the outer peripheral surface of the water conduit 41. Therefore, when adjusting the height of the sand collecting device 2, the upper pipe 53 is moved up and down while being fitted to the lower pipe 52, and the upper end surface of the lower pipe 52 and the outer peripheral surface of the upper pipe 53 are welded together. What is necessary is just to weld by 54. The upper pipe 53 may not be a hollow tube.

  The injection nozzle 42 will be further described. As shown in FIG. 6, the diameter of the injection port 42b of the injection nozzle 42 is, for example, an ellipse of 13 mm × 15 mm, and a U-shaped cut 42c is formed on the front end surface of the injection nozzle 42. It is provided. The injection nozzle 42 and the intermediate flange 42a can be integrally formed in advance, but the intermediate flange 42a can be retrofitted to the existing injection nozzle 42. That is, when the injection nozzle 42 can be screwed, an equivalent nozzle to the intermediate flange 42a can be screwed into the injection nozzle 42. Further, in the case of the injection nozzle 42 that is not screw-connectable, an equivalent of the intermediate flange 42a can be attached to the base end portion of the injection nozzle 42 by welding or the like.

  Here, as can be seen most clearly in FIG. 5, in the positional relationship between the injection nozzle 42 and the mixing tube 43, the front end surface of the injection nozzle 42 is in the vicinity of the junction 47 between the tube main body 43a of the mixing tube 43 and the air introduction tube 43b. It is located in. Further, in the angular relationship between the tube main body 43a and the air introduction tube 43b of the mixing tube 43, the angle θ formed by the tube main body 43a and the air introduction tube 43b is 80 degrees. The angle θ is most preferably 80 degrees, but there is no problem if it is 90 degrees or less. The pipe body 43a naturally sucks air from the air introduction pipe 43b due to the negative pressure generated by the jet flow of the jet nozzle 42. However, an air volume adjusting valve is provided in the pipe line to the air introduction pipe 43b, and the air Can be uniformly ejected from the air introduction pipe 43b.

  When collecting the sand accumulated in the tank body 1, that is, when the tank body 1 is washed, the control means controls the washing water pump 33 and the washing water valve based on the flowchart as shown in FIG. The control means can be controlled by a CRT. When the cleaning water pump 33 is operated by the control means to open the cleaning water valve, water is jetted from the tip of the jet nozzle 42. Thereby, a negative pressure is generated around the jetted water, air is mixed with water from the air introduction pipe 43 b of the mixing pipe 43, and mixed water of water and air is jetted from the tip of the mixing pipe 43. When the mixed water is jetted in this way, a negative pressure is generated around the mixed water, and the mixed water moves as a water stream while sucking and mixing the accumulated sand, and the sand accumulated in the groove 21 is moved to the outlet 19. To discharge from.

  That is, the control means processes as follows. In step ST1, one of the four chambers 16 is selected. In step ST2, manual operation or automatic operation is selected. If manual operation is selected, the start switch is turned on in step ST3. When automatic operation is selected, the cycle timer starts operating. In step ST4, it is determined whether the activation conditions are met. If the activation conditions are not met, the process proceeds to step ST5 ′, the washing water pump 33 is not operated, and the washing water valve is kept closed. When the start conditions are met, the process proceeds to step ST5, the operation of the washing water pump 33 is started, the first and first washing water valves for the most upstream nozzle assembly 31 are opened, and the cycle timer is activated. Let it begin. For example, when 30 seconds elapse, the first and first flush water valves are closed in step ST6, and the first and second flush water valves for the second sand collecting device 2 from the upstream side are opened. Start operation. Similarly, the processing in step ST7 to step ST14 is completed. In step ST15, the operation of the washing water pump 33 is stopped, and the 1st to 10th washing water valves for the last nozzle assembly 31 are closed.

  The activation conditions described above may include that the cleaning water pump 33 is normal, that the cleaning water valve is normal, and that the water level in the selected chamber 16 is greater than or equal to a predetermined level. If any flush water valve fails, that step is skipped and the process proceeds to the next step. When the washing water valve is operated alone, the washing water valve is first set to the fully open position, and then the washing water pump 33 is operated. When the cleaning water pump 33 fails, all the cleaning water valves are closed and the cleaning process is terminated. The cycle timer can be set based on the processing status, input amount, and the like. For example, the cycle timer can be set from several times a day to once a week. The air volume adjusting valve is preferably adjusted so that air is uniformly injected from the air introduction pipe 43b.

  In the sand collecting tank configured in this way, the position of the sand collecting device 2 is increased from the inlet 17 side to the outlet 19 side, and the distance from the bottom is sequentially increased upward, so that the sand collecting device 2 is buried in the sand. It does not interfere with the movement of the sand. Therefore, the sand collecting device 2 can be easily inspected and repaired, and the accumulated sand can be collected efficiently. Moreover, since it is not necessary to incline the bottom face 11a of the bottom 11 or arrange | position the sand collecting apparatus 2 closely, construction cost can be reduced. Since the sand collecting device 2 is configured to be disassembled by the water conduit 41, the injection nozzle 42, and the mixing tube 43, the injection nozzle 42 integrated with the intermediate flange 42a can be easily replaced by simply removing the nut 46. , Can reduce maintenance costs. Further, the tip of the injection nozzle 42 is positioned in the vicinity 47 of the joint portion of the air introduction pipe 43b of the mixing pipe 43, and the angle θ formed by the pipe main body 43a and the air introduction pipe 43b is set to 80 degrees. It is possible to efficiently mix air into the water jets and collect the accumulated sand efficiently.

  Moreover, this sand collection tank can achieve the following effects. That is, since the sand collecting device 2 is arranged linearly on the upstream side and arranged on the outlet 19 side with a gentle curve, the sand can be discharged smoothly from the outlet 19. Since the boundary structure portion 20 is provided between the rows of the sand collecting device 2, it is possible to prevent sand from being deposited between the rows of the sand collecting device 2 and to flow the sand sequentially. . Since the automatic operation is enabled by the control means, the maintenance management becomes easy. Since the sand collecting device 2 is entirely composed of piping, there is nothing to wear out, and the maintenance cost can be reduced. Since the support mechanism 34 of the sand collecting device 2 is composed of the lower pipe 52 and the upper pipe 53, the height of the sand collecting device 2 can be easily changed. Since air is naturally sucked into the water in the mixing pipe 43, it is not necessary to prepare a blower, and the equipment cost can be reduced.

  Although the present invention has been described based on one embodiment, those skilled in the art can easily consider the following modes. That is, the tank body 1 having the two chambers 16 and the four grooves 21 can be a plurality of tank bodies 1. Although the cross-sectional shape of the boundary structure 20 is a mountain, it is not always necessary to provide a rectangular shape as long as there is no hindrance and a sand pool can be prevented. Although the upper surface 11a of the bottom 11 is flattened, the same effect can be obtained when it is stepped or trough (V-shaped). Although the upper surface 11a of the bottom 11 is horizontal, the number of the sand collecting devices 2 can be reduced by inclining so as to decrease from the inflow port 17 toward the outflow port 19 side. The injection nozzle 42 and the intermediate flange 42a are integrated. The bolt 45 and the nut 46 that connect the water guide pipe 41, the injection nozzle 42, and the mixing pipe 43 can be both nut bolts. A spray nozzle shape can also be used for the spray nozzle 42. And the flowchart of a control means can be changed according to the condition of the field, and the cycle timer can be set according to the processing condition and input amount of raw water.

Two tank main bodies 1 were provided, the width of each tank main body 1 was 4.7 m (two 9.4 m), its length was 30 m, and its depth was 4 m. The upper surface 11a of the bottom wall 11 was horizontal, and the boundary structure 20 was mountain-shaped. The width of the bottom surface of each groove 21 was 0.8 m. In each groove 21, 10 rows of sand collecting devices 2 (8 rows in the two tank main bodies 1) are arranged linearly, and the sand collecting devices 2 are arranged in a gentle curve on the downstream side. And the sand collecting apparatus 2 made the installation distance from the bottom face of the sand collecting apparatus 2 high one by one 25 mm toward the water flow direction one by one. Furthermore, the spray pressure of the spray nozzle 42 was 6 kg / cm ² , and the amount of spray water was 0.25 to 0.3 m ³ / min · piece. The injection pressure and the amount of water to be injected can be changed according to the shape, size, sand removal amount, etc. of the tank. When the sand collecting device 2 is operated based on the flowchart shown in FIG. 7, the sand transport range is 1 m (width direction) × 2.5 m to 3 m (sand collecting direction), and the accumulated sand is efficiently discharged. I was able to. At this time, sand accumulation was prevented by operating the sand collecting device 2 about once a week, except at the time of melting snow. Moreover, the same result was able to be acquired even if the upper surface 11a of the bottom 11 was made into trough shape. The angle θ formed between the tube main body 43a and the air introduction tube 43b was 80 ° and 60 °. In this way, the boundary structure 20 is provided, the installation distance from the bottom surface of the sand collecting device 2 is sequentially increased upward, and the sand collecting device 2 is arranged in a gentle curve on the downstream side, so that the accumulated sand is We were able to discharge efficiently.

  As shown in FIGS. 8 and 9, the sand collecting pit 60 has a width of 2 m and a length of 5.5 m. The sand collecting pit 60 has an inclined bottom 61 inclined so as to decrease in the direction of water flow, a horizontal bottom 62 extending horizontally from the end of the inclined bottom 61, and a side inclined bottom having an inclination angle different from that of the inclined bottom 61. 63, and the planar shape of the horizontal bottom 62 is substantially square. The horizontal bottom 62 is provided with a nozzle 66 and a suction pipe 67 of a sand raising device 65 sequentially from below, and an upper part of the suction pipe 67 is provided with a suction pump (not shown) for sucking sand. For example, four sand collecting devices 2 are arranged on the inclined bottom 61. Of these four sand collecting devices 2, the two upstream sand collecting devices 2 are arranged close to the side wall 64 and directed inward by a predetermined angle (for example, 5 degrees). Further, the two sand collecting devices 2 on the downstream side are arranged close to the center line side and oriented along the center line. The angle θ formed between the tube main body 43a and the air introduction tube 43b was 80 ° and 60 °. Also in this Example 2, sand could be discharged efficiently. Moreover, the same result was able to be acquired even if the bottom 61 was made into step shape.

It is a partial horizontal sectional view of a sand collecting tank showing an embodiment of the present invention. It is a sand collecting tank partial vertical sectional view. It is a sand collecting tank cross-sectional view. It is a top view of a sand collecting apparatus. It is the sectional view on the AA line of FIG. It is a perspective view of an injection nozzle. It is a flowchart which shows the process process of a control means. It is a partial horizontal sectional view which shows the sand collecting tank used in Example 2. It is the partial vertical sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water tank 2 Sand collector 17 Inlet 19 Outlet 20 Boundary structure 41 Water conduit 41b Flange 42 Injection nozzle 42a Intermediate flange 43 Mixing pipe 43a Pipe main body 43b Air introduction pipe 43c Flange 47 In the vicinity of the joint

Claims (2)

  In a water tank having a water inlet and a water outlet, and a sand collecting tank including a plurality of sand collecting devices at the bottom of the water tank, the sand collecting device sequentially increases the distance from the bottom from the inlet to the outlet. A sand collection tank characterized by an increase to the top.   The sand collecting tank according to claim 1, further comprising a boundary structure between sand collecting devices installed in two or more rows toward the outlet.

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