Cleaning equipment

Abstract

To provide a small-sized washing apparatus having a high washing effect while suppressing outflow of a material to be washed.SOLUTION: A washing apparatus includes: a container 3 which has an inflow port 341 into which liquid flows and a discharge port 331 in which a turning flow is generated in liquid flowed-in and discharges a part of liquid; a storage tank 4 which stores storage liquid containing contaminants and a material to be washed in a manner of facing a discharge port 331; and a delivery pipe 6 which receives the contaminants and liquid components sucked up from the storage tank 4 from a delivery port 611 connected to the container and discharges the contaminants and liquid components from the other end 6a arranged below the delivery port 611. The container 3 has an orifice section 32 in which cross sectional area of an internal space X1 defined by an inner peripheral surface of the container 3 is reduced on the discharge port 331 side more than that on the inflow port 341 side between the inflow port 341 and the discharge port 331. The delivery port 611 has opening area larger than that of the discharge port 311. The discharge port 331 is in a state of being connected to the storage liquid stored in the storage tank 4.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a cleaning device for cleaning an object to be cleaned. [Background technology]

[0002] Sewage treatment facilities are equipped with settling basins for removing sand from wastewater. In the settling basin, sand contained in the received wastewater is collected in a sand collection pit at the bottom of the basin, and the collected sand is then transported together with the wastewater using a sand-lifting pump. The sand and wastewater transported by the sand-lifting pump contain contaminants such as sediment and organic matter. Most of these contaminants have a lower specific gravity than sand. The transported sand is sometimes disposed of in landfills. However, if the sand contains a large amount of contaminants, it may emit methane gas and other contaminants, which may prevent the landfill from accepting the sand. There is also a demand for washing the soil and sand to remove clay contaminants. Hereinafter, sand, soil, and other contaminants that require washing are collectively referred to as the "object to be washed." For this reason, washing devices that remove the contaminants from the liquid containing the contaminants and the object to be washed are sometimes installed in sewage treatment facilities (see, for example, Patent Document 1). The scrubbing apparatus disclosed in Patent Document 1 agitates wastewater using an agitator attached to the wall of the scrubbing tank, but separates the impurities and sand primarily by settling the sand, which has a high specific gravity. This requires a scrubbing tank to store a large amount of water to float the impurities while settling the sand, resulting in a problem of increased size of the scrubbing apparatus. Another problem is that impurities with specific gravities close to or greater than that of water are difficult to separate from the sand. In response to this problem, scrubbing apparatuses have been developed that use a sand-washing cyclone to wash wastewater containing impurities and sand (see, for example, Patent Document 2). The scrubbing apparatus disclosed in Patent Document 2 has a weir and an annular trough above the sand-washing cyclone. In this scrubbing apparatus, the impurities mixed in the wastewater flowing into the sand-washing cyclone are drawn into the ascending current generated within the sand-washing cyclone along with the wastewater, sent to the top of the sand-washing cyclone, and then sent out of the scrubbing apparatus through the annular trough. The washing device of Patent Document 2 can be made smaller by using a sand washing cyclone. In addition, because a sand washing cyclone is used, it is possible to draw in impurities with a specific gravity close to or greater than that of water into the rising flow and send them out of the washing device through the annular gutter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 54-72866 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-59755 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the washing device disclosed in Patent Document 2 is configured so that wastewater containing sand and impurities transported from a sand lifting pump flows into a sand washing cyclone, where the sand settles at the bottom of the cyclone and is then dumped onto a recovery conveyor connected to the opening at the bottom of the cyclone. As a result, sand before being dumped onto the recovery conveyor accumulates at the bottom of the sand washing cyclone and is easily drawn into the upward flow within the cyclone and sent to the top of the cyclone, potentially causing a considerable amount of sand to overflow the weir and flow out of the washing device. While attempts to address this issue by weakening the upward flow to the extent that sand is not dumped outside the washing device result in the impurities being more difficult to draw into the upward flow, resulting in a reduced washing effect.

[0005] In view of the above circumstances, an object of the present invention is to provide a small-sized cleaning device that has a high cleaning effect while suppressing the outflow of the objects to be cleaned. [Means for solving the problem]

[0006] The cleaning device of the present invention, which solves the above-mentioned object, comprises: a container having an inlet through which a liquid flows and an outlet that generates a swirling flow in the flowing liquid and discharges a portion of the liquid; a storage tank facing the discharge port for storing a liquid containing impurities and objects to be cleaned; a delivery pipe that receives the impurities and liquid components sucked up from the storage tank through a delivery port connected to the container and discharges them from the other end located below the delivery port; the container has a constricted portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner peripheral surface of the container is smaller on the outlet side than on the inlet side, The delivery port has an opening area larger than an opening area of ​​the discharge port, The discharge port is a discharge port for discharging the stored liquid stored in the storage tank. The nozzle is slightly spaced from the liquid surface and faces the liquid surface, and the periphery of the discharge port is covered by a part of the liquid discharged from the discharge port and the liquid surface. It is characterized in that it is in a state where ... [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a small-sized cleaning device that has a high cleaning effect while suppressing the outflow of the object to be cleaned. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a settling basin in which a cleaning device corresponding to one embodiment of the present invention is disposed. [Figure 2] 2(a) is a plan view of the container shown in FIG. 1, and FIG. 2(b) is a cross-sectional view taken along the line AA in FIG. 2(a). [Figure 3] 2 is a front view showing the container, the storage tank, and the lower part of the carrying-out device shown in FIG. 1. FIG. [Figure 4] 2 is a right side view showing the container, the storage tank, and the lower part of the carrying-out device shown in FIG. 1. FIG. [Figure 5] 2 is a flowchart showing the operation of the cleaning device shown in FIG. [Figure 6] 1. FIG. 4 is a front view similar to FIG. 3, showing a first modified example of the cleaning device shown in FIG. [Figure 7] 1. FIG. 4 is a front view similar to FIG. 3, showing a second modified example of the cleaning device shown in FIG. [Figure 8] 1. FIG. 5 is a right side view similar to FIG. 4, showing a third modified example of the cleaning device shown in FIG. [Figure 9] FIG. 2 is a schematic diagram similar to FIG. 1, showing a second embodiment of the cleaning device. [Figure 10] 10 is a flowchart showing the operation of the cleaning device shown in FIG. [Figure 11] FIG. 4 is a front view similar to FIG. 3, showing a third embodiment of the cleaning device. [Figure 12] 12 is a flowchart showing the operation of the cleaning device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of this embodiment, an example will be used in which the present invention is applied to a washing device that washes sand by removing impurities and wastewater from wastewater containing impurities and sand transported from a grit basin and then discharges the washed sand. In this embodiment, the sand corresponds to an example of an object to be washed. The grit basin is located upstream of a sewage treatment facility and is used to remove sand from wastewater such as sewage or rainwater. The wastewater from which sand has been removed in the grit basin is sent to a sedimentation basin or the like downstream. Furthermore, the impurities are separated from the wastewater by an impurity removal screen device or the like and treated.

[0010] FIG. 1 is a schematic diagram showing a grit basin in which a cleaning device corresponding to one embodiment of the present invention is disposed.

[0011] As shown in FIG. 1, the settling basin 9 in which the cleaning device 1 of this embodiment is installed is a basin equipped with a pump well 91, a trough 92, a sand collection nozzle 93, and a sand collection pit 94. Wastewater flows into the settling basin 9 from the right side of the figure. The flowing wastewater slowly flows toward the left side of the figure. As the wastewater flows through the settling basin 9, the sand contained in the wastewater settles toward the bottom of the basin. The pump well 91 is located at the most downstream side of the settling basin 9. The pump well 91 is a portion where the wastewater from which sand has been removed is stored. A lifting pump 911 is installed inside the pump well 91. The lifting pump 911 sends the wastewater stored in the pump well 91 to the outside of the settling basin 9. A lifting pipe 912 is connected to the lifting pump 911. The wastewater sucked by the lifting pump 911 is sent through the lifting pipe 912 to a settling basin (not shown). The sewage pond water level WL1 is also shown in Figure 1. The position of this pond water level WL1 varies in height from the bottom of the trough 92 within a range of, for example, 1 m to 5 m depending on the amount of sewage flowing into the settling basin 9.

[0012] The trough 92 is formed in the center of the pond width direction at the bottom of the pond upstream of the pump well 91. This trough 92 extends along the direction in which the wastewater flows in the settling basin 9. On both sides of the trough 92 in the pond width direction, a pond bottom slope 95 is formed on the bottom of the pond that slopes downward toward the trough 92. The sand contained in the wastewater that flows into the settling basin 9 settles toward the bottom of the pond and slides down the pond bottom slope 95 or is deposited directly in the trough 92.

[0013] The sand collection nozzle 93 is disposed at the upstream end of the trough 92. The sand collection nozzle 93 is supplied with wastewater pumped up from the above-mentioned sedimentation basin (not shown). The wastewater supplied to the sand collection nozzle 93 is discharged from the tip of the sand collection nozzle 93 toward the downstream side of the sedimentation basin 9. The downstream end of the trough 92 is connected to a sand collection pit 94. Sand deposited in the trough 92 is collected in the sand collection pit 94 by the flow of water discharged from the sand collection nozzle 93.

[0014] The sand collection pit 94 is formed between the pump well 91 and the trough 92. The sand collected in the sand collection pit 94 is sent to the washing device 1 by a sand lifting pump 941. The sand lifting pump 941 is located inside the sand collection pit 94 near the bottom of the sand collection pit 94. A sand lifting pipe 942 is connected to the sand lifting pump 941. The sand lifting pump 941 sucks the sand collected inside the sand collection pit 94 together with the wastewater, and transfers the wastewater mixed with sand into the container 3 through the sand lifting pipe 942. The sand and wastewater transferred by the sand lifting pump 941 contain impurities such as screen residue and organic matter. Most of these impurities have a lower specific gravity than sand. Hereinafter, the wastewater mixed with impurities and sand transferred into the container 3 by the sand lifting pump 941 will be referred to as mixed water. This mixed water corresponds to an example of a liquid. The percentage of sand contained in the mixed water transferred into container 3 by sand lifting pump 941 varies depending on the amount of sand collected inside sand collection pit 94, but is approximately 5% on average. The mixed water transferred into container 3 by sand lifting pump 941 is approximately 2.0 m3 / min. The amount of mixed water flowing into container 3 is determined by the capacity of sand lifting pump 941. For this reason, the sand lifting pump 941 is selected appropriately depending on the size of container 3 and storage tank 4. However, in order to balance the amount of impurities and liquid components pumped from storage tank 4 (described below) with the concentrated water (described below) released from outlet 331 provided at the bottom of container 3, it is preferable to use a sand lifting pump 941 that allows mixed water to flow into container 3 at a rate of 2.0 m3 / min or more. On the other hand, using a sand-lifting pump 941 with an unnecessarily high capacity will only increase the price and power consumption of the sand-lifting pump 941, so it is preferable to use a sand-lifting pump 941 that allows the amount of mixed water flowing into the container 3 to be 4 m3 / min or less.

[0015] The washing apparatus 1 includes a container 3, a storage tank 4, a discharge device 5, and a delivery pipe 6. The container 3, the storage tank 4, and the delivery device 5 are disposed on the ground near a settling basin 9. The washing apparatus 1 of this embodiment also corresponds to an example of a sand separation device that separates sand from entrained water. The lower portion of the container 3 is disposed within the storage tank 4, and the upper portion of the container 3 protrudes above the storage tank 4. The container 3 is a so-called liquid cyclone that removes a certain amount of wastewater and impurities from the entrained water that has flowed in and delivers the water to the delivery pipe 6. The container 3 also discharges concentrated water, which has a higher concentration of sand due to the removal of a certain amount of wastewater and impurities, into the storage tank 4. This discharged concentrated water corresponds to an example of a portion of a liquid. The wastewater and impurities delivered directly from the container 3 to the delivery pipe 6 are returned to the settling basin 9 through the delivery pipe 6 together with impurities and liquid components pumped up from the storage tank 4 (described later). Hereinafter, the wastewater and impurities delivered directly from the container 3 to the delivery pipe 6 and the impurities and liquid components pumped up from the storage tank 4 and delivered to the delivery pipe 6 will be collectively referred to as delivery water. Hereinafter, the sand, impurities, and liquid components stored in the storage tank 4 will be collectively referred to as stored liquid. The delivery pipe 6 has one end 61 connected to the container lid 312 of the container 3, a horizontal portion extending horizontally above the container 3, and a vertical portion bending from the horizontal portion and extending downward. The other end 6a, which is the lower end of the vertical portion, is located below the container 3 and outside the storage tank 4, upstream of the settling basin 9. By arranging the other end 6a upstream of the sand collection pit 94 of the settling basin 9, even if sand is accidentally discharged from the cleaning device 1 through the delivery pipe 6, the sand will settle to the bottom of the settling basin 9 as it flows downstream, and can be transferred back into the container 3. The other end 6a of the delivery pipe 6 may be extended below the water level WL1 of the settling basin 9 so that the other end 6a is submerged in water. Furthermore, the other end 6a may be arranged near the bottom of the settling basin 9. The container 3 and the storage tank 4 will be described in detail later.

[0016] The unloading device 5 is connected to the lower end of the storage tank 4 and extends diagonally upward. This unloading device 5 corresponds to an example of a discharge section. The unloading device 5 has a screw conveyor 51 and a drop port 52. The screw conveyor 51 is disposed within the unloading device 5. The axial direction of the screw conveyor 51 coincides with the extension direction of the unloading device 5. A motor 53 and a drive transmission mechanism 54 are fixed to the upper end portion of the unloading device 5. By driving this motor 53, the screw conveyor 51 rotates via the drive transmission mechanism 54. Note that the drive transmission mechanism 54 is composed of sprockets fixed to the drive shaft of the motor 53 and the screw conveyor 51, and chains wound around each sprocket, but it may also be composed of other mechanical transmission elements such as gears. Alternatively, the motor 53 and the screw conveyor 51 may be directly connected without providing the drive transmission mechanism 54. The sand contained in the concentrated water released into the storage tank 4 settles within the storage tank 4 and flows into the discharge device 5 connected to the storage tank 4, where it is drained and transported diagonally upward as the screw conveyor 51 rotates. The drop port 52 is located near the upper end of the screw conveyor 51. The sand drained by the screw conveyor 51 is dropped downward from the drop port 52. In other words, the discharge device 5 discharges the sand contained in the liquid stored in the storage tank 4 to the outside of the storage tank 4. Note that instead of the screw conveyor 51, another discharge mechanism such as a belt conveyor may be used. In that case, the other discharge mechanism such as the belt conveyor corresponds to an example of a discharge unit.

[0017] Fig. 2(a) is a plan view of the vessel shown in Fig. 1, and Fig. 2(b) is a cross-sectional view taken along line AA in Fig. 2(a). Fig. 2(a) and Fig. 2(b) also show one end portion 61 of the delivery pipe 6 and a part of the sand lifting pipe 942.

[0018] As shown in FIG. 2(b), the container 3 includes a liquid introduction section 31, a throttle section 32, a discharge section 33, and a liquid inlet pipe 34. The liquid introduction section 31 is provided in the upper portion of the container 3. The upper end of the throttle section 32 is connected to the lower end of the liquid introduction section 31. The upper end of the discharge section 33 is connected to the lower end of the throttle section 32. The inner circumferential surface 3a of the container 3 is formed by the inner circumferential surface 31a of the liquid introduction section 31, the inner circumferential surface 32a of the throttle section 32, and the inner circumferential surface 33a of the discharge section 33. The inner circumferential surface 3a of the container 3 defines an internal space X1. In other words, the liquid introduction section 31, the throttle section 32, and the discharge section 33 form a hollow tank having the internal space X1.

[0019] The liquid introduction part 31 includes a cylindrical part 311 having a cylindrical inner circumferential surface 31a, and a container lid 312 that closes the upper end of the cylindrical part 311. The cylindrical part 311 is made of a 3.2 mm thick steel plate processed into a cylindrical shape with an inner diameter of 500 mm. The container lid 312 is made of a 6.0 mm thick steel plate processed into a ring shape with an outer diameter of 586 mm and an inner diameter of 216 mm. The container lid 312 is provided with an inspection door (not shown), which allows air to flow into and out of the container 3. The shape, material, and thickness of the cylindrical part 311 and the container lid 312 may be selected appropriately depending on the size of the internal space X1, etc.

[0020] The liquid inlet pipe 34 is connected to the upper portion of the cylindrical portion 311. The sand lifting pump 941 and liquid inlet pipe 34 shown in FIG. 1 are connected via a sand lifting pipe 942. The sand lifting pipe 942 and liquid inlet pipe 34 are detachably connected by bolting together flanges at the connecting ends. The liquid inlet pipe 34 has an inner diameter of 100 mm. As shown in FIG. 2(b), an inlet 341 is formed at the connection between the liquid inlet pipe 34 and the cylindrical portion 311. As indicated by the straight arrow pointing right in FIGS. 2(a) and 2(b), the mixed water sucked up by the sand lifting pump 941 is introduced into the internal space X1 through the inlet 341 in the tangential direction of the inner circumferential surface 31a of the cylindrical portion 311. This creates a swirling flow of mixed water in the internal space X1.

[0021] The throttle section 32 is disposed between the inlet 341 and the discharge section 33. In this throttle section 32, the cross-sectional area of ​​the internal space X1 decreases toward the discharge section 33. In other words, the throttle section 32 has an inverted conical inner circumferential surface 32a whose diameter gradually decreases with increasing distance from the cylindrical section 311. This throttle section 32 is formed by processing a steel plate with a thickness of 3.2 mm into a conical shape, with an inner diameter of 500 mm at the upper end and 100 mm at the lower end. The material and thickness of the throttle section 32 may be appropriately selected depending on the size of the internal space X1, the amount of narrowing, and the like. The throttle section 32 may also be formed so that the cross-sectional area of ​​the internal space X1 gradually decreases with increasing distance from the cylindrical section 311. That is, the throttle section 32 may be formed so that the cross-sectional area of ​​the internal space X1 is smaller on the discharge outlet 331 side than on the inlet 341 side. The cross-sectional area of ​​the lower end of the throttle section 32 is equal to the opening area of ​​the discharge outlet 331. In this embodiment, the cross-sectional area of ​​the lower end of the throttle section 32, i.e., the opening area (cross-sectional area) of the discharge port 331, is set to match the opening area (cross-sectional area) of the inlet 341. However, the opening area of ​​the discharge port 331 may be equal to or larger than the opening area of ​​the inlet 341. However, if the opening area of ​​the discharge port 331 is made too small, the pressure loss in the container 3 increases, so the opening area of ​​the discharge port 331 is preferably equal to or larger than the opening area of ​​the inlet 341. In addition, if the opening area of ​​the discharge port 331 is made too small or too large, the suction action from the storage tank 4 to the container 3, which will be described later, decreases, so it is desirable to set the opening area of ​​the discharge port 331 to be 50% or more and 150% or less of the opening area of ​​the inlet 341. A container flange 321 protruding toward the outside of the container 3 is formed at the upper end of the throttle section 32.

[0022] The discharge section 33 is connected to the side of the throttle section 32 opposite to the side to which the liquid introduction section 31 is connected. In other words, the discharge section 33 is connected to the lower end of the throttle section 32. The discharge section 33 is cylindrical with a flange 332 formed at the lower end. The opening at the lower end of this discharge section 33 becomes the discharge port 331. The discharge section 33 may be omitted. In that case, the opening at the lower end of the throttle section 32 becomes the discharge port. The flange 332 is annular with an outer diameter of 200 mm.

[0023] The delivery pipe 6 has an inner diameter of 200 mm. One end portion 61 of the delivery pipe 6 is watertightly connected to the container lid 312 by welding. The one end portion 61 may protrude into the internal space X1. The lower end of the one end portion 61 forms one end of the delivery pipe 6, and the opening of that end forms the delivery outlet 611. Therefore, the one end portion 61 and the delivery outlet 611 are connected to the container 3. The delivery outlet 611 is located in the center of the container 3 in a plan view. The delivery water is delivered from the delivery outlet 611 to the outside of the container 3. The delivery water delivered from the delivery outlet 611 is returned to the settling basin 9 through the delivery pipe 6. In Figures 2(a) and 2(b), the flow direction of the delivery water is indicated by a straight arrow pointing left. The opening area of ​​the delivery outlet 611 is preferably equal to or larger than the opening area of ​​the discharge port 331. This increases the amount of water delivered from outlet 611, reducing pressure loss in container 3. The opening area of ​​outlet 611 is preferably equal to or larger than the opening area of ​​inlet 341. This allows a larger amount of fluid to be delivered from outlet 611 than the mixed water flowing in from inlet 341. In this embodiment, the opening area of ​​outlet 611 is four times the opening areas of discharge port 331 and inlet 341.

[0024] Fig. 3 is a front view showing the container, the storage tank, and the lower part of the carrying-out device shown in Fig. 1. Fig. 4 is a right side view showing the container, the storage tank, and the lower part of the carrying-out device shown in Fig. 1.

[0025] As shown in FIG. 3 , the storage tank 4 includes a sidewall 41 positioned outside the container 3 and extending above the discharge port 331, a tank lid 42 closing the upper end of the sidewall 41, and legs 43 supporting the storage tank. In this embodiment, the sidewall 41 extends from below the discharge port 331 to the height of the joint between the throttled section 32 and the liquid introduction section 31. A hole having the same diameter as the outer periphery of the liquid introduction section 31 of the container 3 is formed in the center of the tank lid 42 in a plan view. The container 3 is joined to the storage tank 4 by welding the container flange 321 to the tank lid 42 with the upper end portion of the throttled section 32 inserted into the hole. A deodorizing pipe 421 is provided on the tank lid 42. The legs 43 are located at each of the four corners of the storage tank 4 in a plan view. In FIG. 3 , only the upper and lower ends of the legs 43 are shown, with the middle portion omitted. The lower ends of the legs 43 are grounded, allowing the storage tank 4 to be placed above ground. It should be noted that a support member for supporting the carry-out device 5 is also provided at the middle portion of the carry-out device 5 in the extending direction, but this support member is not shown.

[0026] The upper portion of the storage tank 4 is formed as a rectangular tube with a substantially square shape in a plan view. As shown in FIG. 4, a tank inclined surface 41a is formed on the lower portion of the storage tank 4. The lower end of this tank inclined surface 41a is connected to the discharge device 5. Also, as shown in FIG. 3, the lower end of the storage tank 4 is notched obliquely upward at the same angle as the inclination of the discharge device 5. Sand contained in the concentrated water discharged from the discharge port 331 of the container 3 slides down the tank inclined surface 41a or is deposited in the lower portion of the discharge device 5, which is directly connected to the lower end of the storage tank 4. As described above, the sand deposited in the discharge device 5 is discharged to the outside of the cleaning apparatus 1 by the screw conveyor 51. A discharge pipe 55 is connected to the lower end of the discharge device 5 for discharging liquid and sand remaining in the storage tank 4 and the discharge device 5 during inspection, etc. This discharge pipe 55 is equipped with a valve (not shown) that is opened when discharging liquid and sand during inspection, etc., and is normally closed. 3 and 4 also show a tank liquid level WL2 formed at a height facing the discharge port 331 by the stored liquid discharged from the discharge port 331.

[0027] Next, we will explain the driving method and operation of this cleaning device 1. Figure 5 is a flowchart showing the operation of the cleaning device shown in Figure 1.

[0028] The operations of the settling basin 9 and the cleaning device 1 are centrally controlled by a control device (not shown). The settling basin 9 and the cleaning device 1 may each be provided with a control device, allowing them to transmit and receive information or commands to and from each other. When a certain amount of sand accumulates on the bottom of the settling basin 9 shown in FIG. 1 at a predetermined time, the settling basin 9 discharges wastewater from a sand collection nozzle 93 to collect the sand accumulated in the trough 92 in a sand collection pit 94. After the sand collection operation, the cleaning device 1 begins a cleaning operation. The predetermined time may be periodically, for example, once a month, or when the total flow rate of wastewater flowing into the settling basin 9 or the total flow rate of wastewater discharged from the settling basin 9 reaches a certain amount. The cleaning operation may also be initiated while sand is being collected in the sand collection pit 94. The cleaning device 1 of this embodiment also functions as a sand separator, so sand is discharged during the cleaning operation.

[0029] In the cleaning operation, first, the operation of the discharge device 5 is started (Step S10). While the discharge device 5 is operating, sand accumulated in the lower portion of the discharge device 5 is transported diagonally upward along the discharge path of the discharge device 5. The sand transported by the screw conveyor 51 is drained while being transported in the latter half of the discharge path, which is higher than the tank liquid level WL2. Then, the sand that reaches the upper end of the discharge path of the discharge device 5 is discharged by being dropped downward from the drop port 52. After the operation of the discharge device 5 is started, the operation of the sand lifting pump 941 is then started. This start of operation starts the inflow of mixed water into the container 3 (Step S11). Since the mixed water flows in from the tangential direction of the inner circumferential surface 31a of the cylindrical portion 311, a swirling flow of mixed water is formed near the inner circumferential surface 3a of the container 3 in the internal space X1. The sand contained in the mixed water has a greater specific gravity than the impurities and wastewater. Therefore, centrifugal force presses the sand against the inner circumferential surface 3a of the container 3, causing it to gradually fall downward while circulating along the inner circumferential surface 3a. Meanwhile, the impurities and wastewater, from which the sand has been removed, gather in the radial center of the container 3, generating an upward flow. This upward flow causes the impurities and wastewater gathered in the center to be discharged from the outlet 611 at the top end of the container 3. The discharged impurities and wastewater pass through the delivery pipe 6 and are released into the settling basin 9 from the other end 6a of the delivery pipe 6. Because the other end 6a of the delivery pipe 6 is located below the outlet 611 formed at one end of the delivery pipe 6, when the delivery pipe 6 is filled with liquid, a force is generated that sucks up the mixed water and other substances in the internal space X1 from the outlet 611 and flows them into the settling basin 9 due to the siphon principle. This increases the amount of water delivered, and enhances the suction action at the discharge port 331, which will be described later.

[0030] In the internal space X1, the sand gradually falls downward while swirling along the inner circumferential surface 3a, and begins to be discharged as concentrated water from the discharge port 331 together with a certain amount of impurities and wastewater (step S12). The concentrated water is discharged from the discharge port 331 in a tangential direction of the discharge port 331 due to the centrifugal force of the swirling flow. In Figures 3 and 4, the direction of concentrated water discharge is indicated by a curved arrow. If the storage tank 4 is empty when the discharge of concentrated water begins, the tank liquid level WL2 in the storage tank 4 gradually rises. Furthermore, the sand contained in the stored liquid stored in the storage tank 4 settles toward the bottom of the storage tank 4 due to its own weight and accumulates in the lower part of the carry-out device 5. Note that as the amount of accumulated sand increases, the sand that does not fit into the lower part of the carry-out device 5 also accumulates in the lower part of the storage tank 4. Among the impurities contained in the stored liquid, those with a low specific gravity float in the wastewater, which is the supernatant liquid of the stored liquid, while those with a high specific gravity slowly settle in the wastewater.

[0031] As the tank liquid level WL2 rises and reaches a height facing the discharge port 331 (YES in step S13), as shown in FIGS. 3 and 4, the wastewater, which is the supernatant liquid of the stored liquid facing the discharge port 331, is sucked into the discharge port 331 along with the suspended impurities (step S14). The wastewater sucked into the discharge port 331 is an example of a liquid component. Hereinafter, the impurities sucked into the discharge port 331 and the wastewater will be collectively referred to as the impurity-containing liquid component. In FIG. 4, the concentrated water being discharged from the discharge port 331 is shown cross-hatched in an enlarged circle. In this enlarged view, the container 3, the tank liquid level WL2, and the concentrated water are indicated by solid lines. As shown in this enlarged view, the concentrated water is discharged toward the outer periphery of the discharge port 331 due to the kinetic energy of the swirling flow. At a height position where the tank liquid level WL2 faces the discharge port 331 with a slight gap between them, the discharged concentrated liquid is connected to the stored liquid, thereby connecting the discharge port 331 to the tank liquid level WL2. In this state, the discharge port 331 is covered by the discharged concentrated water and the tank liquid level WL2. Negative pressure is generated in the radial center of the discharge port 331 due to the upward flow occurring in the container 3. This negative pressure causes the supernatant liquid of the stored liquid near the radial center of the discharge port 331 and the impurities floating therein to be sucked into the discharge port 331 as impurity-containing liquid components. In other words, the state in which the impurity-containing liquid components are sucked into the container 3 from the discharge port 331 due to the negative pressure is one example of the state in which the discharge port 331 is connected to the stored liquid. In Figures 3 and 4, the direction in which the impurity-containing liquid components are sucked is indicated by a straight arrow. When this impurity-containing liquid component is sucked into the outlet 331, the air around the outlet 331 is also sucked into the outlet 331. That is, an amount of impurity-containing liquid component and air greater than the amount of concentrated water being released is sucked into the outlet 331. In this embodiment, the delivery port 611 is formed with an opening area larger than the outlet 331, so that a large amount of fluid can be delivered from the delivery port 611. As a result, the impurity-containing liquid component and air can be easily sucked into the outlet 331.Furthermore, even if an amount of impurity-containing liquid component and air greater than the amount of concentrated water being released is sucked in through the discharge port 331, the impurity-containing liquid component and air can still be discharged through the delivery port 611. When the impurity-containing liquid component and air are being sucked in through the discharge port 331, a balanced state is formed in which the amount of concentrated water released into the storage tank 4 from the discharge port 331 and the amount of impurity-containing liquid component sucked into the internal space X1 from the discharge port 331 are approximately equal. The volume of air sucked into the discharge port 331 is less than one-fifth the volume of the impurity-containing liquid component. In this embodiment, a flange 332 extending horizontally is formed around the discharge port 331, making it difficult for air above the discharge port 331 to be sucked into the discharge port 331. Furthermore, the flange 332 suppresses rippling of the tank liquid level WL2 near the discharge port 331. These features make it difficult for air to be drawn into the outlet 331, increasing the ratio of impurity-containing liquid components drawn into the outlet 331 relative to air. Furthermore, the flange 332 facilitates the orderly discharge of concentrated water from the outlet 331. As a result, sand contained in the concentrated water discharged from the outlet 331 is prevented from mixing with the impurity-containing liquid components drawn from the radial center of the outlet 331. At a height position where the tank liquid level WL2 faces the outlet 331, the average distance between the tank liquid level WL2 and the outlet 331 is 0 mm or more and 20 mm or less. As described above, the concentrated water is discharged from the outlet 331 toward the outer periphery of the outlet 331, so sand contained in the concentrated water is unlikely to be drawn into the central portion of the outlet 331. Additionally, sand has a high specific gravity and tends to settle quickly downward in the storage tank 4. For this reason, even if a strong upward flow is formed in container 3 and the suction force generated at discharge port 331 is strong, only a very small amount of sand is sucked into container 3. Because this very small amount of sand has a higher specific gravity than the impurity-containing liquid components, most of it is repelled from the upward flow toward the outer periphery within container 3, swallowed by the swirling flow, and then released again from discharge port 331 into storage tank 4. As described above, air is also sucked in from discharge port 331, so the upward flow generated in the center of container 3 is a flow of fluid with a low specific gravity that is mixed with the sucked air.Therefore, the difference in specific gravity between the fluid that mainly constitutes the upward flow and the sand becomes greater, and the sand with a higher specific gravity is more likely to be repelled toward the outer periphery. Also, the stored liquid in the storage tank 4 is agitated by the released concentrated water. This agitation makes it easier for impurities contained in the stored liquid that have a higher specific gravity than the liquid components of the stored liquid to rise up and float in the stored liquid.

[0032] If the amount of contaminated water flowing into the container 3 is less than 2.0 m3 / min, the amount of impurity-containing liquid components drawn into the discharge port 331 will be less than the concentrated water discharged from the discharge port 331, and the tank liquid level WL2 may rise beyond the discharge port 331. However, when the tank liquid level WL2 reaches the discharge port 331, the discharge port 331 is blocked by the stored liquid, and the amount of concentrated water discharged from the discharge port 331 decreases. That is, the resistance caused by the reduced cross-sectional area of ​​the internal space X1 in the throttle section 32, combined with the water pressure of the stored liquid acting on the discharge port 331, makes it difficult for the concentrated water to be discharged from the discharge port 331. As the tank liquid level WL2 rises, the water pressure of the stored liquid acting on the discharge port 331 increases, and the amount of concentrated water discharged from the discharge port 331 decreases, and the amount of water discharged from the delivery port 611 increases. Furthermore, as described above, when the delivery pipe 6 is filled with liquid, the delivery water tends to flow out of the delivery port 611 into the grit basin 9 due to the siphon principle, further increasing the amount of delivery water delivered from the delivery port 611. As a result, the amount of impurity-containing liquid components drawn into the discharge port 331 increases, causing the tank liquid level WL2 to drop to a position facing the discharge port 331. That is, while the tank liquid level WL2 is dropping, an amount of impurity-containing liquid components greater than the amount of concentrated water discharged from the discharge port 331 is being drawn in. In this way, reducing the amount of contaminated water flowing into the container 3 allows the use of an inexpensive sand pump 941, thereby reducing the amount of electricity used by the sand pump 941. When the tank liquid level WL2 is above the discharge port 331, the discharge port 331 is submerged in the liquid stored in the storage tank. However, even in this state, the liquid remains facing the discharge port 331. That is, when the discharge port 331 is submerged in the stored liquid stored in the storage tank 4, the stored liquid that covers the discharge port 331 faces the discharge port 331. Depending on the amount of mixed water flowing into the container 3 and the strength of the swirling flow in the container 3, the tank liquid level WL2 may stagnate above the discharge port 331 even when the water pressure of the stored liquid acting on the discharge port 331 or the action due to the siphon principle occurs.

[0033] When a first predetermined time has elapsed since the start of operation of the sand raising pump 941 (YES in step S15), the operation of the sand raising pump 941 is stopped (step S16). This first predetermined time is the time required for the sand raising pump 941 to suck up most of the sand collected in the sand collection pit 94, and is set appropriately depending on the capacity of the sand raising pump 941 and the amount of sand that can be collected in the sand collection pit 94. Stopping the sand raising pump 941 also stops the inflow of mixed water into the container 3, the release of concentrated water into the storage tank 4, the suction of impurity-containing liquid components, and the delivery of delivery water. Steps S11 to S16 described above correspond to an example of an inflow process. Steps S14 to S16 correspond to an example of a release / suction process.

[0034] When a second predetermined time has elapsed since the operation of the sand lifting pump 941 was stopped (YES in step S17), the operation of the discharge device 5 is stopped (step S18). Steps S10 to S18 described above correspond to an example of a discharge process. This second predetermined time is the sum of the time it takes for the sand contained in the concentrated liquid discharged from the discharge port 331 to settle to the lower part of the discharge device 5 and the time it takes for the sand to be transported from the lower part of the discharge device 5 to the drop port 52. Instead of determining whether the second predetermined time has elapsed, a sand presence / absence sensor that detects the presence or absence of sand in the lower part of the discharge device 5 may be provided in the discharge device 5, and the sand in that part may be determined to have been depleted. This completes the operation of the cleaning apparatus 1. While the discharge device 5 is operating, the tank liquid level WL2 is located at a position substantially aligned with the discharge port 331. Therefore, even if the discharge path is short, the sand can be transported while draining. Because the discharge path extends diagonally upward, shortening the discharge path shortens the width and height of the discharge device 5. As a result, the size of the cleaning device 1 can be reduced. According to the cleaning device 1 of this embodiment, not only is sewage and impurities separated from sand from the contaminated water that flows into the container 3 and the impurities and sewage discharged from the outlet 611, but also, while discharging the impurities and sewage from the outlet 611, the impurities and liquid components are sucked up from the stored liquid stored in the storage tank 4 and discharged from the outlet 611, so that clean sand free of impurities can be left in the storage tank 4. Furthermore, since the sand in the container 3 is prevented from reaching the outlet 611, the sand can also be prevented from being discharged from the outlet 611. As a result, a high cleaning effect can be obtained while suppressing the outflow of sand.

[0035] Next, a modified example of this embodiment will be described. In the following description, the names of components that are the same as those described above may be assigned the same reference numerals as those used above, and duplicate descriptions may be omitted.

[0036] FIG. 6 is a front view similar to FIG. 3, showing a first modified example of the cleaning device shown in FIG.

[0037] As shown in FIG. 6, the cleaning apparatus 1 of this first modified example differs from the cleaning apparatus 1 shown in FIG. 1 in that a cleaning water supply pipe 45 is connected to the storage tank 4. The cleaning water supply pipe 45 penetrates the side wall 41 of the storage tank 4 in a watertight manner. A discharge port 451 is formed at the tip of the cleaning water supply pipe 45. The discharge port 451 is located inside the storage tank 4 at the lower end portion of the storage tank 4. The discharge port 451 is also located below the release port 331. The discharge port 451 is used to generate a liquid flow in the stored liquid stored in the storage tank 4. A valve 452 is provided on the cleaning water supply pipe 45. By opening the valve 452, purified water is discharged from the discharge port 451. As a result, purified water is injected into the storage tank 4 at a rate of approximately 0.2 m3 / min. This purified water corresponds to an example of a fluid. In this first modified example, the discharge water is discharged from the delivery port 611 at a rate of approximately 2.2 m3 / min. In this first modification, valve 452 is a manual valve, but it may also be an electrically operated valve. Discharge port 451 discharges purified water toward the sand accumulated at the bottom of storage tank 4. This configuration not only generates a liquid flow in the stored liquid but also stirs up the accumulated sand and impurities, lifting the impurities buried in the sand. This makes it easier for the impurities to be sucked into discharge port 331, resulting in a high cleaning effect. If the amount of purified water discharged from outlet 611 is increased or the discharge pressure is increased, sand will also be blown up to the vicinity of discharge port 331 and will be more likely to be sucked into discharge port 331. However, in this cleaning device 1, most of the sand sucked into container 3 is ejected from the upward flow toward the outer periphery within container 3, absorbed into the swirling flow, and then released again into storage tank 4 from discharge port 331. Therefore, in this cleaning device 1, by increasing the amount of purified water discharged from the delivery port 611 or by increasing the discharge pressure, it is possible to obtain a high cleaning effect while suppressing sand from being discharged from the delivery pipe 6 and flowing into the grit basin 9. Note that although the cleaning effect will be reduced compared to when the delivery port 451 is disposed at a position submerged in water, the delivery port 451 may be provided at the upper end portion of the storage tank 4 and purified water may be injected from above the tank liquid level WL2. Furthermore, there may be multiple delivery ports 451, and delivery ports 451 may be provided below and above the discharge port 331.In particular, when there is excess capacity to suck impurity-containing liquid components into container 3 from outlet 331 and a lot of air is being sucked in through outlet 331, it is preferable to increase the number of discharge ports 451 or the amount of purified water discharged from outlet 451, thereby increasing the amount of purified water supplied to storage tank 4. This makes it possible to raise more impurities and increase the amount of impurity-containing liquid components sucked into container 3 from outlet 331, thereby improving the cleaning ability of cleaning device 1.

[0038] The injection of purified water into the storage tank 4 is performed between step S11 (starting the operation of the sand lifting pump 941) and step S16 (stopping the operation of the sand lifting pump 941) shown in FIG. 5, i.e., during the inflow process. However, injection may be started before step S11 so that the tank liquid level WL2 faces the discharge port 331 in advance. In this case, the suction of the impurity-containing liquid component is started simultaneously with the discharge of the concentrated water. From step S14 onward, the height position of the tank liquid level WL2 and the height position of the discharge port 331 become approximately the same. The injection of purified water into the storage tank 4 may be performed after step S11, for example, between step S14 (starting the suction of the impurity-containing liquid component) and step S16 (stopping the operation of the sand lifting pump 941), i.e., during the discharge / suction process. This process of injecting purified water into the storage tank 4 corresponds to an example of an injection process. Injecting purified water can improve the cleaning effect of the cleaning device 1.

[0039] Alternatively, a fine bubble water generator (not shown) may be provided to inject fine bubble water into the reservoir 4 instead of purified water. Fine bubble water is a liquid containing fine bubbles of 100 μm or less. Fine bubble water may be a liquid containing microbubbles, which are bubbles with a diameter of more than 1 μm and 100 μm or less, or may be a liquid containing ultrafine bubbles, which are bubbles with a diameter of 1 μm or less. Furthermore, fine bubble water may be a liquid containing both microbubbles and ultrafine bubbles. The use of fine bubble water can further enhance the cleaning effect of the cleaning device 1. This fine bubble water corresponds to an example of a fluid.

[0040] Fig. 7 is a front view similar to Fig. 3, showing a second modified example of the cleaning device shown in Fig. 1. In the explanation of the second modified example, differences from the first modified example shown in Fig. 6 will be mainly described.

[0041] As shown in FIG. 7, the cleaning apparatus 1 of this second modified example differs from the cleaning apparatus 1 shown in FIG. 6 in that a cleaning water supply pipe 45 is connected to the carry-out device 5. The cleaning water supply pipe 45 penetrates the upstream wall of the carry-out device 5 in a watertight manner. The outlet 451 is located within the carry-out device 5 at the lower end portion of the carry-out device 5. The outlet 451 is also located below the discharge port 331. The outlet 451 discharges purified water upward. In this second modified example, the outlet 451 discharges purified water from below the sand accumulated in the carry-out device 5 toward above, thereby stirring up a large amount of sand and impurities. As described above, fine bubble water may be discharged from the outlet 451 instead of purified water. Alternatively, gas may be discharged from the outlet 451 instead of purified water. In this case, the gas corresponds to an example of a fluid. In addition to the discharge port 451 provided in the carry-out device 5, a discharge port 451 may also be provided in the lower end portion or the upper end portion of the storage tank 4.

[0042] Fig. 8 is a right side view similar to Fig. 4, showing a third modified example of the cleaning device shown in Fig. 1. In the explanation of the third modified example, differences from the first modified example shown in Fig. 6 will be mainly described.

[0043] As shown in FIG. 8, the cleaning apparatus 1 of this third modified example differs from the cleaning apparatus 1 shown in FIG. 6 in that a cleaning water supply pipe 45 is connected to a discharge pipe 55. The cleaning water supply pipe 45 is connected to the discharge pipe 55 on the screw conveyor 51 side of a valve provided on the discharge pipe 55. The cleaning water supply pipe 45 supplies purified water to the discharge pipe 55 when the valve provided on the discharge pipe 55 is closed. The discharge pipe 55 is connected from the side of the discharge device 5 at the lower end of the screw conveyor 51 inside the discharge device 5 where sand has accumulated. Therefore, the supplied purified water is discharged from the side into the discharge device 5 from the connection part between the discharge pipe 55 and the discharge device 5. In other words, in this third modified example, the connection part between the discharge pipe 55 and the carry-out device 5 is the discharge port 451. In FIG. 8, for ease of understanding, the discharge port 451 is shown slightly protruding into the carry-out device 5. The discharge port 451 is located lower than the discharge port 331. In this third modified example, outlet 451 discharges purified water horizontally from the side of the sand accumulated in carry-out device 5 toward the sand, thereby stirring up a large amount of sand and impurities. In this third modified example, fine bubble water may also be discharged from outlet 451 instead of purified water. Also, gas may be discharged from outlet 451 instead of purified water. Furthermore, in addition to outlet 451 at the connection between discharge pipe 55 and carry-out device 5, outlet 451 may also be provided at the lower or upper end of storage tank 4.

[0044] Next, a second embodiment will be described. Fig. 9 is a schematic diagram similar to Fig. 1, showing a second embodiment of the cleaning device.

[0045] As shown in FIG. 9 , the sedimentation basin 9 of the second embodiment differs from the washing apparatus 1 and sedimentation basin 9 shown in FIG. 1 in that it does not have a trough 92, sand collection nozzle 93, sand collection pit 94, basin bottom slope 95, sand lifting pump 941, or sand lifting pipe 942, but instead has a grab bucket type sand lifting device 96, and in that treated water flows into the container 3. The sedimentation basin 9 is equipped with the grab bucket type sand lifting device 96. The grab bucket type sand lifting device 96 includes a rail 961, a mobile winch 962, and a grab bucket 963. The rail 961 is supported by a support 9611 erected above ground in the sedimentation basin 9. The rail 961 spans the entire longitudinal length of the sedimentation basin 9. The mobile winch 962 is configured to be movable along the rail 961. The grab bucket 963 is suspended from the mobile winch 962. The grab bucket 963 grabs the sand deposited at the bottom of the settling basin 9 and lifts it to the ground using a mobile winch 962. This sand contains impurities. The sand lifted to the ground is dumped into the storage tank 4 with the tank lid 42 open. A treated water pipe 97, which supplies treated water (described later), is connected to the liquid inlet pipe 34 of the container 3.

[0046] FIG. 10 is a flowchart showing the operation of the cleaning apparatus shown in FIG.

[0047] At a predetermined time when a certain amount of sand has accumulated on the bottom of the settling basin 9 shown in FIG. 9 , the grab bucket-type sand lifting device 96 is operated to dump the sand, including impurities, that has accumulated on the bottom of the settling basin into the storage tank 4. After the dumping, the tank lid 42 is closed, and the cleaning device 1 begins the cleaning operation. Note that if the container 3 is installed using an installation device that positions the container 3 in the position shown in FIGS. 3 and 4 , the timing for closing the tank lid 42 does not matter. In that case, the tank lid 42 may be omitted. In the cleaning operation, first, the supply of treated water into the container 3 begins. The treated water is water treated in a sewage treatment facility and is supplied into the container 3 by pressure-feeding it through the treated water pipe 97 using a pump. Instead of the treated water, untreated wastewater from a sedimentation basin or the like may be supplied, or tap water or natural water may be supplied. In other words, water obtained from a source other than the settling basin may be supplied. In this second embodiment, the treated water or the like supplied into the container 3 corresponds to an example of a liquid. When the supply of treated water into the vessel 3 begins, the treated water begins to flow into the vessel 3 (step S21). The treated water flows in from the tangential direction of the inner circumferential surface 31a of the cylindrical portion 311, and a swirling flow of treated water is formed in the internal space X1 near the inner circumferential surface 3a of the vessel 3. This swirling flow causes the inflowing treated water to gradually move downward while swirling along the inner circumferential surface 3a. Meanwhile, an upward flow is generated in the radial center of the vessel 3. This upward flow causes a certain amount of the inflowing treated water to be discharged directly from the discharge outlet 611 at the upper end of the vessel 3. As shown in FIG. 9, the discharged treated water passes through the discharge pipe 6 and is released from the other end 6a of the discharge pipe 6 toward the settling basin 9.

[0048] In the internal space X1, a portion of the treated water gradually moves downward while swirling along the inner circumferential surface 3a, reaches the discharge port 331, and begins to be discharged from the discharge port 331 (step S22). The centrifugal force of the swirling flow causes a portion of the treated water to be discharged from the discharge port 331 in a tangential direction of the discharge port 331. Because sand containing impurities has accumulated in the storage tank 4, a portion of the released treated water falls onto the sand, forming a tank liquid level WL2 in the storage tank 4. As a portion of the treated water is discharged, the tank liquid level WL2 gradually rises. In this second embodiment, the sand containing impurities that was originally introduced into the storage tank 4 and a portion of the treated water released into the storage tank 4 become the stored liquid. When the tank liquid level WL2 rises and reaches a height position facing the discharge port 331 (YES in step S23), the supernatant liquid of the stored liquid facing the discharge port 331 is sucked in from the center of the discharge port 331 (step S24). Furthermore, the stored liquid stored in the storage tank 4 is agitated by the released treated water, so that the accumulated impurities rise up and are sucked into the discharge port 331 together with the supernatant liquid of the stored liquid. This supernatant liquid sucked into the discharge port 331 corresponds to an example of a liquid component. Furthermore, the impurities and the supernatant liquid sucked into the discharge port 331 become the impurity-containing liquid component. When the impurity-containing liquid component is sucked into the discharge port 331, the air around the discharge port 331 is also sucked into the discharge port 331. That is, an amount of impurity-containing liquid components and air equal to or greater than a portion of the amount of the discharged treated water is sucked through the discharge port 331. While the impurity-containing liquid components and air are being sucked through the discharge port 331, a balanced state is formed in which the amount of treated water released through the discharge port 331 into the storage tank 4 and the amount of impurity-containing liquid components sucked through the discharge port 331 into the internal space X1 are approximately equal. Here, sand contained in the stored liquid is stirred to some extent, but because of its greater specific gravity than the treated water, it rarely rises to the vicinity of the tank liquid level WL2. Therefore, even if the suction force generated at the discharge port 331 is strong, only a small amount of sand is sucked into the container 3. Furthermore, because the specific gravity of sand is greater than that of the impurity-containing liquid components, even if it is sucked in, most of it is repelled from the upward flow toward the outer periphery within the container 3, swallowed by the swirling flow, and then released again through the discharge port 331 into the storage tank 4.

[0049] As in the previous embodiment, when the amount of treated water flowing into the vessel 3 is less than 2.0 m / min, the tank liquid level WL2 may rise above the discharge port 331. However, once the tank liquid level WL2 has risen, it will fall to a position facing the discharge port 331 due to the water pressure acting on the discharge port 331 and the effect of the siphon principle.

[0050] When a third predetermined time has elapsed since the start of the supply of treated water (YES in step S25), the supply of treated water is stopped (step S26). This third predetermined time is the time required to suck up impurities mixed in the sand in the storage tank 4 together with the liquid components of the stored liquid. This third predetermined time may be a time set in advance based on experimental results, or may be a time input by the operator depending on the amount of sand introduced into the storage tank 4 and the degree of impurities mixed in. Stopping the supply of treated water also stops the inflow of treated water into the container 3, the release of a portion of the treated water into the storage tank 4, the suction of impurity-containing liquid components, and the delivery of the delivery water. Steps S21 to S26 described above correspond to an example of an inflow process. Steps S24 to S26 correspond to an example of a release / suction process. After the supply of treated water is stopped, the operation of the discharge device 5 is started (step S27). When a fourth predetermined time has elapsed since the start of operation of the carry-out device 5 (YES in step S28), the operation of the carry-out device 5 is stopped (step S29). This fourth predetermined time is the time required for all sand accumulated in the lower portion of the carry-out device 5 to be transported to the drop port 52 and discharged. This fourth predetermined time may be a time set in advance taking into account the expected amount of accumulated sand, or may be a time input by the operator depending on the amount of sand introduced into the storage tank 4. Note that instead of determining whether the fourth predetermined time has elapsed, a sand presence / absence sensor that detects the presence or absence of sand in the lower portion of the carry-out device 5 may be provided in the carry-out device 5, and whether or not the sand in that portion has been depleted may be determined. Steps S27 to S29 described above correspond to an example of a discharge process. Note that the operation of the carry-out device 5 may be started before the supply of treated water is stopped (step S26). However, in this second embodiment, it is preferable to drive the carry-out device 5 after the supply of treated water is stopped (after cleaning is completed) because there is a risk that sand containing impurities before cleaning may be discharged from the drop port 52. In this second embodiment as well, impurities and liquid components are sucked up from the liquid stored in the storage tank 4, so clean sand without impurities can be left in the storage tank 4. In addition, the sand is prevented from reaching the delivery port 611, so the sand can also be prevented from being delivered from the delivery port 611. As a result, a high cleaning effect can be obtained while suppressing the outflow of sand.

[0051] Next, a third embodiment will be described. Fig. 11 is a front view similar to Fig. 3, showing a third embodiment of the cleaning device. In the description of this third embodiment, differences from the cleaning device 1 shown in Fig. 6 will be mainly described.

[0052] As shown in FIG. 11 , the cleaning apparatus 1 of the third embodiment differs from the cleaning apparatus 1 shown in FIG. 6 in the structure of the bottom of the storage tank 4 and in the provision of a belt gate 7 instead of the discharge device 5. This belt gate 7 corresponds to an example of a discharge unit. An opening 4a is formed in the bottom of the storage tank 4. In FIG. 11 , this opening 4a is blocked by a belt gate 7 indicated by a solid line. The opening 4a of the storage tank 4 is tilted upward by 3° from right to left in the figure. The belt gate 7 is also tilted upward by 3° and disposed at the bottom of the storage tank 4. However, the opening 4a and the belt gate 7 may be disposed horizontally. When the opening 4a is blocked by the belt gate 7, the liquid stored in the storage tank 4 is prevented from being discharged through the opening 4a. Hereinafter, the state in which the opening 4a is blocked by the belt gate 7 shown in FIG. 11 is referred to as a blocked state. The belt gate 7 includes multiple rollers 71 extending perpendicular to the plane of the drawing in FIG. 11 and a belt 72 wound around these rollers 71. Of the multiple rollers 71, the rollers 71 located at both ends in FIG. 11 are drive rollers. Driving these drive rollers 71 moves the belt gate 7 from its closed position to the left. Hereinafter, the direction in which the belt gate 7 moves from its closed position is referred to as the opening direction. Because the belt gate 7 is well known, detailed description is omitted, and the belt gate 7 is shown simplified in the drawings, omitting the drive mechanism, frame, and other components. As the belt gate 7 moves from its closed position to the opening direction, all of the openings 4a are opened, as indicated by the dashed line in FIG. 11. As the belt gate 7 moves in the opening direction, the sand accumulated on the belt gate 7, along with the liquid components of the stored liquid, is discharged from the storage tank 4 through the opening 4a of the storage tank 4. As the belt gate 7 moves in the opening direction, the stored liquid with an extremely high sand concentration is discharged outside the storage tank 4. Hereinafter, the state of the belt gate 7 in which all of the openings 4a are open will be referred to as the open state. The belt gate 7 moves to the right from the open state indicated by the dashed dotted line by the drive roller 71. Hereinafter, the direction in which the belt gate 7 moves from the open state position will be referred to as the closing direction.In other words, the belt gate 7 changes the state of the cleaning device 1 between a closed state and an open state, and by changing it to the open state, the stored liquid with an extremely high concentration of sand inside the storage tank 4 is discharged outside the storage tank 4.

[0053] Moreover, in this third embodiment, the flushing water supply pipe 45 passes through the side wall 41 of the storage tank 4 in a watertight manner. The discharge port 451 is positioned below the discharge port 331 and so as to discharge purified water horizontally toward the lower end portion of the storage tank 4. In other words, the discharge port 451 discharges purified water toward the sand accumulated on the belt gate 7 that closes the bottom of the storage tank 4.

[0054] FIG. 12 is a flowchart showing the operation of the cleaning apparatus shown in FIG.

[0055] In the cleaning operation, the sand lifting pump 941 is first started. This starts the inflow of contaminated water into the container 3 (step S31). Steps S31 to S36 are similar to steps S11 to S16 shown in FIG. 5 except that the discharge device 5 is not driven, and therefore a detailed description is omitted. Steps S31 to S36 correspond to an example of an inflow process. Steps S34 to S36 correspond to an example of a discharge / suction process. Furthermore, in this third embodiment, similar to the cleaning apparatus 1 shown in FIG. 6, during steps S31 to S36, i.e., during the inflow process, purified water is discharged from the discharge port 451 to inject purified water into the storage tank 4. The discharge port 451 discharges purified water horizontally from the side of the sand accumulated in the discharge device 5 toward the sand, thereby stirring up a large amount of sand and impurities. Furthermore, a liquid flow can be generated in the stored liquid stored in the storage tank 4. This step of injecting purified water into the storage tank 4 corresponds to an example of an injecting step. Injecting purified water can improve the cleaning effect of the cleaning device 1. Note that, in this third modified example, fine bubble water may be ejected from the outlet 451 instead of purified water. Also, gas may be ejected from the outlet 451 instead of purified water.

[0056] In step S36, when the driving of the sand lifting pump 941 is stopped, the belt gate 7 is moved in the opening direction to be in an open state (step S37). By moving the belt gate 7, the sand accumulated on the belt gate 7 is discharged outside the storage tank 4. This step S37 corresponds to an example of a discharging step. Note that before the storage tank 4 is opened, a truck is made to wait below the storage tank 4. The sand discharged from the storage tank 4 falls into the bed of the truck or a container provided on the bed and is carried by the truck. After the sand in the storage tank 4 has been discharged, the belt gate 7 is moved in the closing direction to be in a closed state (step S38), and the cleaning operation is completed. The cleaning device 1 of this third embodiment can also obtain the same effects as the cleaning device 1 shown in FIG.

[0057] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims. For example, in this embodiment, an example in which the cleaning device 1 is installed in the settling basin 9 has been described, but the cleaning device 1 may be installed in a location other than a settling basin. Also, an example in which the cleaning device 1 is used to clean sand has been described, but the cleaning device 1 may also be used to clean other objects to be cleaned, such as soil and sand. Furthermore, a discharge mechanism other than the screw conveyor 51 and belt gate 7 may be used as the discharge section.

[0058] According to the above-described embodiment and modified examples, a small-sized cleaning device can be obtained that has a high cleaning effect while suppressing the outflow of sand.

[0059] Note that even if a component is included only in the description of the embodiment or each modified example described above, that component may be applied to other embodiments or other modified examples.

[0060] The cleaning device described above includes a container having an inlet through which a liquid flows and an outlet through which a swirling flow is generated in the flowing liquid and a part of the liquid is discharged, a storage tank facing the discharge port for storing a liquid containing impurities and objects to be cleaned; a discharge section for discharging the object to be cleaned contained in the liquid stored in the storage tank, the container has a constricted portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner peripheral surface of the container is smaller on the outlet side than on the inlet side, The discharge port is characterized in that it is connected to the liquid stored in the storage tank.

[0061] The cleaning device described above includes a container having an inlet through which a liquid flows and an outlet through which a swirling flow is generated in the flowing liquid and a part of the liquid is discharged, a storage tank facing the discharge port for storing a liquid containing impurities and objects to be cleaned; a discharge section for discharging the object to be cleaned contained in the liquid stored in the storage tank, the container has a constricted portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner peripheral surface of the container is smaller on the outlet side than on the inlet side, The outlet is connected to the liquid stored in the storage tank, thereby It is characterized by being able to suck in air, liquid components of the stored liquid, and impurities.

[0062] The swirling flow generates an upward flow in the center of the container, generating negative pressure in the center of the outlet. Therefore, when the stored liquid in the storage tank is connected to the outlet, the stored liquid near the outlet is sucked into the container from the center of the outlet where negative pressure is generated. At this time, the objects to be cleaned contained in the stored liquid may also be sucked into the container. However, since the objects to be cleaned have a higher specific gravity than the impurities and liquid components of the stored liquid, the objects sucked into the container are likely to be ejected by the upward flow and released back into the storage tank. Conversely, the impurities in the storage tank have a lower specific gravity, so they tend to float up within the storage tank and be sucked through the outlet, and the impurities sucked into the container tend to rise on the upward flow within the container. This prevents the object to be cleaned from flowing out along with the liquid components of the stored liquid and impurities, while sending the impurities in the storage tank out of the cleaning device, thereby obtaining an object to be cleaned from which the impurities have been removed.

[0063] Here, the container may be a cyclone into which liquid flows. The discharge port may be disposed within the storage tank. Furthermore, when connected to the stored liquid stored in the storage tank, the discharge port may be covered by the stored liquid. Furthermore, the discharge port may be connected to the liquid surface of the stored liquid stored in the storage tank. When the discharge port is connected to the liquid surface of the stored liquid stored in the storage tank, the discharge port and the liquid surface may be slightly spaced apart, and the periphery of the discharge port may be covered by a portion of the liquid discharged from the discharge port and the liquid surface, or the liquid surface may be in contact with the discharge port. Furthermore, the discharge port may be submerged in the stored liquid stored in the storage tank. When the discharge port is submerged in the stored liquid stored in the storage tank, the portion of the stored liquid covering the discharge port faces the discharge port. In addition, the liquid flowing into the container may be wastewater containing contaminants and the objects to be cleaned. The discharge unit may be a conveyor that transports the objects to be cleaned, or a gate or valve that can open and close the bottom side of the storage tank. The discharge unit may also be connected to the lower end of the storage tank. Note that the contaminants may have a lower specific gravity than the liquid components of the stored liquid, and the objects to be cleaned may have a higher specific gravity than the liquid components.

[0064] In this cleaning device, a discharge port for discharging a fluid that generates a liquid flow in the liquid stored in the storage tank may be provided at a position below the discharge port.

[0065] The liquid flow can lift up impurities that settle to the bottom of the storage tank or that have accumulated at the bottom of the storage tank and suck them into the container through the outlet. If the liquid flow vigorously stirs the stored liquid in the storage tank, the objects to be cleaned will tend to fly upward and be sucked into the container through the outlet. However, in this cleaning device, as described above, the objects to be cleaned that have been sucked into the container are likely to be released back into the storage tank. Therefore, this cleaning device can achieve a high cleaning effect while preventing the objects from flowing out along with the liquid components of the stored liquid and impurities.

[0066] Here, the discharge port may be one that discharges the fluid horizontally or upward. Also, the discharge port may be one that is disposed in the discharge section. In addition, the discharge port may be one that discharges the fluid toward the objects to be cleaned that are piled up in the discharge section.

[0067] In this cleaning device, the container may be connected to a delivery port having an opening area larger than the opening area of ​​the discharge port.

[0068] Since the opening area of ​​the delivery port is large, most of the impurities and liquid components of the stored liquid sucked in from the release port can be delivered from the delivery port, making it easier to suck in the impurities and liquid components of the stored liquid from the release port. The cleaning device described above also includes a container having an inlet through which a liquid flows and an outlet through which a swirling flow is generated in the flowing liquid and a part of the liquid is discharged; a storage tank facing the discharge port for storing a liquid containing impurities and objects to be cleaned; a delivery pipe that receives the impurities and liquid components sucked up from the storage tank through a delivery port connected to the container and discharges them from the other end located below the delivery port; the container has a constricted portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner peripheral surface of the container is smaller on the outlet side than on the inlet side, The delivery port has an opening area larger than an opening area of ​​the discharge port, The discharge port is characterized in that it is connected to the liquid stored in the storage tank. [Explanation of symbols]

[0069] 1 Cleaning equipment 3 containers 4. Reservoir 5 Unloading device 32 Constriction section 331 Outlet 341 Inlet X1 interior space

Claims

[Claim 1] a container having an inlet through which a liquid flows and an outlet through which a swirl flow is generated in the flowing liquid and a portion of the liquid is discharged; a storage tank facing the discharge port for storing a liquid containing impurities and objects to be cleaned; a delivery pipe that receives the impurities and liquid components sucked up from the storage tank through a delivery port connected to the container and discharges them from the other end located below the delivery port; the container has a constricted portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner peripheral surface of the container is smaller on the outlet side than on the inlet side, The delivery port has an opening area larger than an opening area of ​​the discharge port, A cleaning device characterized in that the release outlet faces the liquid surface of the stored liquid stored in the storage tank at a slight distance from the liquid surface, and the area around the release outlet is covered by a portion of the liquid released from the release outlet and the liquid surface.

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