Washing apparatus

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] A sedimentation basin is provided in a sewage treatment facility to remove sand from wastewater. In the sedimentation 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 by a sand lifting pump. The sand and wastewater transported by the sand lifting pump contain impurities such as sediment and organic matter. Most of these impurities have a lower specific gravity than sand. The transported sand may be buried in a landfill disposal site. However, if there is a large amount of impurities mixed in the sand, methane gas may be generated, and the landfill disposal site may not accept the sand. There is also a demand to wash the soil and sand to remove the clay content, which is an impurity. Hereinafter, sand, soil, etc. that need to be washed are collectively referred to as the washed object. For this reason, a washing device that washes the washed object by removing the impurities from the liquid in which the impurities and the washed object are mixed may be installed in a sewage treatment facility (see, for example, Patent Document 1, etc.). The washing device disclosed in Patent Document 1 is configured to separate impurities and sand by so-called sedimentation separation, in which the sand, which has a large specific gravity, is mainly separated by settling, although the wastewater is agitated by an agitator provided on the wall of the washing tank. For this reason, a washing tank is required to store a large amount of water to make the sand settle while floating the impurities, which causes a problem that the washing device becomes large. There is also a problem that impurities with a specific gravity close to or larger than that of water are difficult to separate from the sand. In response to this, a washing device has been developed that uses a sand-washing cyclone to wash the wastewater containing impurities and sand (see, for example, Patent Document 2, etc.). In the washing device of Patent Document 2, a weir and an annular gutter are provided at the top of the sand-washing cyclone. In this washing device, the impurities mixed in the wastewater that flows into the sand-washing cyclone are drawn into the upward flow generated in the sand-washing cyclone together with the wastewater, sent to the top of the sand-washing cyclone, and sent to the outside of the washing device through the annular gutter. According to the cleaning device of Patent Document 2, the size of the cleaning device can be reduced by using a sand washing cyclone. In addition, since the sand washing cyclone is used, it is possible that impurities with a specific gravity close to or larger than that of water can be drawn into the upward flow and sent out of the cleaning 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] JP 2013-59755 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the washing device disclosed in Patent Document 2 is configured such that wastewater containing sand and impurities transferred from a sand lifting pump is fed into a sand washing cyclone, where the sand settles at the bottom of the sand washing cyclone and is then fed into a recovery conveyor connected to the opening at the bottom of the sand washing cyclone. As a result, the sand before being fed into the recovery conveyor accumulates at the bottom of the sand washing cyclone and is easily drawn into the upward flow in the sand washing cyclone and sent to the top of the sand washing cyclone, and there is a risk that a considerable amount of sand will overflow the weir and flow out of the washing device. If, as a countermeasure, an attempt is made to weaken the upward flow to the extent that the sand is not sent out of the washing device, it becomes difficult for impurities to be drawn into the upward flow, resulting in a problem of 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 that solves the above-mentioned object includes 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 for storing a liquid containing impurities and objects to be cleaned, facing the discharge port; 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 constriction portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner circumferential 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. Effect 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 description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a grit basin in which a cleaning device corresponding to one embodiment of the present invention is disposed. [Diagram 2] 2A is a plan view of the container shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG. [Diagram 3] 2 is a front view showing the container, the storage tank, and the lower part of the discharge device shown in FIG. 1. [Figure 4] 2 is a right side view showing the container, the storage tank, and the lower part of the discharge device shown in FIG. 1. [Diagram 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 configuration 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 PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of this embodiment, an example is 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 transferred from a grit basin, and discharges the washed sand. In this embodiment, the sand corresponds to an example of an object to be washed. The grit basin is disposed on the upstream side of a sewage treatment facility, and is intended 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 located downstream. In addition, 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 settling basin in which a cleaning device corresponding to one embodiment of the present invention is disposed.

[0011] As shown in FIG. 1, the grit basin 9 in which the cleaning device 1 of this embodiment is disposed 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 grit basin 9 from the right side of the figure. The flowing wastewater slowly flows toward the left side of the figure. In the grit basin 9, while the wastewater flows, the sand contained in the wastewater settles toward the bottom of the basin. The pump well 91 is disposed at the most downstream side of the grit basin 9. The pump well 91 is a portion in which the wastewater from which sand has been removed is stored. A lifting pump 911 is provided inside the pump well 91. This lifting pump 911 sends the wastewater stored in the pump well 91 to the outside of the grit 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 sedimentation basin (not shown). The sewage pond water level WL1 is also shown in Fig. 1. The position of this pond water level WL1 varies in height from the bottom of the trough 92 to, 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 pond bottom upstream of the pump well 91, in the center in the pond width direction. This trough 92 extends along the direction in which the wastewater flows in the grit basin 9. On both sides of the trough 92 in the pond width direction, a pond bottom slope 95 is formed in the pond bottom, which slopes downward toward the trough 92. Sand contained in the wastewater that flows into the grit basin 9 settles toward the pond bottom and slides down the pond bottom slope 95 or is directly deposited 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 settling 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 settling basin 9. The downstream end of the trough 92 is connected to a sand collection pit 94. The sand accumulated 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 cleaning device 1 by the sand lifting pump 941. The sand lifting pump 941 is disposed inside the sand collection pit 94 and 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 the 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 sediment and organic matter. Most of these impurities have a lower specific gravity than sand. Hereinafter, the wastewater mixed with impurities and sand transferred by the sand lifting pump 941 into the container 3 is referred to as mixed water. And, this mixed water corresponds to an example of a liquid. The ratio of sand contained in the mixed water transferred into the container 3 by the sand pump 941 varies depending on the amount of sand collected inside the sand collection pit 94, but is about 5% on average. The mixed water transferred into the container 3 by the sand pump 941 is about 2.0 m3 / min. The amount of mixed water flowing into the container 3 is determined by the capacity of the sand pump 941. For this reason, the sand pump 941 is appropriately selected according to the size of the container 3 and the storage tank 4. However, in order to balance the amount of impurities and liquid components sucked up from the storage tank 4 described later and the concentrated water discharged from the discharge port 331 provided at the bottom end of the container 3 described later, it is preferable to use a sand pump 941 that allows the amount of mixed water flowing into the container 3 to be 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 cleaning device 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 the grit basin 9. The cleaning device 1 of this embodiment also corresponds to an example of a sand separation device that separates sand from mixed water. The lower part of the container 3 is disposed in the tank of the storage tank 4, and the upper part of the container 3 protrudes above the storage tank 4. The container 3 is a so-called liquid cyclone, which removes wastewater and impurities to a certain extent from the mixed water that has flowed in and delivers the water to the delivery pipe 6. The container 3 also discharges concentrated water, in which the concentration of sand has been increased by removing a certain amount of wastewater and impurities, into the storage tank 4. This discharged concentrated water corresponds to an example of a part of a liquid. The wastewater and impurities sent directly from the container 3 to the delivery pipe 6 are returned to the grit basin 9 through the delivery pipe 6 together with impurities and liquid components sucked up from the storage tank 4 described later. Hereinafter, the wastewater and impurities sent directly from the container 3 to the delivery pipe 6 and the impurities and liquid components sucked up from the storage tank 4 and sent to the delivery pipe 6 are collectively referred to as delivery water. Hereinafter, the sand, impurities and liquid components stored in the storage tank 4 are collectively referred to as stored liquid. The delivery pipe 6 has one end portion 61 connected to the container lid 312 of the container 3, a horizontal portion extending horizontally above the container 3, and a vertical portion bent 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, in the upstream part of the grit basin 9. By locating the other end 6a upstream of the sand collection pit 94 of the settling basin 9, even if sand is accidentally sent out 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, so that it 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 located near the bottom of the settling basin 9. The container 3 and the storage tank 4 will be described in detail later.

[0016] The discharge device 5 is connected to the lower end of the storage tank 4 and extends obliquely upward. This discharge device 5 corresponds to an example of a discharge section. The discharge device 5 has a screw conveyor 51 and a drop port 52. The screw conveyor 51 is arranged in the discharge device 5. The axial direction of the screw conveyor 51 coincides with the extension direction of the discharge device 5. A motor 53 and a drive transmission mechanism 54 are fixed to the upper end part of the discharge 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, respectively, and chains wound around each sprocket, but may be composed of other transmission mechanical elements such as gears. In addition, 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 discharged into the storage tank 4 sinks in the storage tank 4 and flows into the discharge device 5 connected to the storage tank 4, and is conveyed diagonally upward while being drained by the rotation of the screw conveyor 51. The drop port 52 is disposed 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. That is, 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 inflow pipe 34. The liquid introduction section 31 is provided in the upper part 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 peripheral surface 3a of the container 3 is composed of the inner peripheral surface 31a of the liquid introduction section 31, the inner peripheral surface 32a of the throttle section 32, and the inner peripheral surface 33a of the discharge section 33. The inner peripheral surface 3a of the container 3 defines an internal space X1. That is, 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 peripheral surface 31a, and a container lid 312 closing the upper end of the cylindrical part 311. The cylindrical part 311 is a steel plate having a thickness of 3.2 mm processed into a cylindrical shape with an inner diameter of 500 mm. The container lid 312 is a steel plate having a thickness of 6.0 mm 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), and air can flow into the container 3 and out of the container 3 through the inspection door. The shape, material, and thickness of the cylindrical part 311 and the container lid 312 may be appropriately selected according to the size of the internal space X1, etc.

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

[0021] The throttle section 32 is disposed between the inlet 341 and the outlet 33. In this throttle section 32, the cross-sectional area of ​​the internal space X1 decreases toward the outlet 33. In other words, the throttle section 32 has an inverted cone-shaped inner peripheral surface 32a that gradually decreases in diameter as it moves away from the cylindrical section 311. This throttle section 32 is formed by processing a steel plate with a plate thickness of 3.2 mm into a cone shape, and is formed with an inner diameter of 500 mm at the upper end and an inner diameter of 100 mm at the lower end. The material and thickness of the throttle section 32 may be appropriately selected according to the size of the internal space X1, the amount of throttle, and the like. The throttle section 32 may also be formed so that the cross-sectional area of ​​the internal space X1 decreases stepwise as it moves away 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 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 outlet 331. In this embodiment, the cross-sectional area of ​​the lower end of the throttling portion 32, i.e., the opening area (cross-sectional area) of the discharge port 331 is made to coincide with the opening area (cross-sectional area) of the inlet 341, but 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 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 throttling portion 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 its 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 is a pipe with an inner diameter of 200 mm. One end portion 61 of the delivery pipe 6 is joined to the container lid 312 in a watertight state by welding. The one end portion 61 may protrude into the internal space X1. The lower end of the one end portion 61 becomes one end of the delivery pipe 6, and the opening of the one end becomes 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 disposed 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 grit basin 9 through the delivery pipe 6. In Fig. 2(a) and Fig. 2(b), the flow direction of the delivery water is indicated by a straight arrow pointing left. It is preferable that the opening area of ​​the delivery outlet 611 is equal to or larger than the opening area of ​​the discharge port 331. This increases the amount of water discharged from the outlet 611, and reduces pressure loss in the container 3. The opening area of ​​the outlet 611 is preferably equal to or larger than the opening area of ​​the inlet 341. This allows a larger amount of fluid to be discharged from the outlet 611 than the mixed water flowing in from the inlet 341. The opening area of ​​the outlet 611 in this embodiment is four times the opening areas of the discharge port 331 and the 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. Also, 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 side wall 41 disposed outside the container 3 and extending above the discharge port 331, a tank lid 42 closing the upper end of the side wall 41, and legs 43 supporting the storage tank. In this embodiment, the side wall 41 extends from below the discharge port 331 to the height of the joint between the throttling 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 throttling section 32 inserted into the hole. The tank lid 42 is provided with a deodorizing tube 421. The legs 43 are disposed at the four corners of the storage tank 4 in a plan view. In FIG. 3, the legs 43 are omitted from the middle portion and only the upper end portion and the lower end portion are shown. The lower end portion of the legs 43 is grounded, so that the storage tank 4 is placed on the ground. Incidentally, a support member for supporting the carry-out device 5 is also provided at the intermediate portion in the extending direction of the carry-out device 5, but this support member is omitted in the drawing.

[0026] The upper part of the storage tank 4 is formed as a rectangular cylinder having a substantially square shape in a plan view. As shown in FIG. 4, a tank inclined surface 41a is formed in the lower part 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 cut obliquely upward at the same angle as the inclination angle of the discharge device 5. The 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 directly deposited in the lower part of the discharge device 5 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 device 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 provided 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, a description will be given of a driving method and operation of the cleaning apparatus 1. Fig. 5 is a flow chart showing the operation of the cleaning apparatus shown in Fig. 1.

[0028] The operations of the grit basin 9 and the cleaning device 1 are centrally controlled by a control device (not shown). Note that the grit basin 9 and the cleaning device 1 may each be provided with a control device, and may be configured to be capable of transmitting and receiving information or commands to each other. At a predetermined time when the amount of sand accumulated on the bottom surface of the grit basin 9 shown in FIG. 1 reaches a certain amount, the grit basin 9 performs a sand collection operation in which wastewater is discharged from the sand collection nozzle 93 to collect the sand accumulated in the trough 92 in the sand collection pit 94. After the sand collection operation, the cleaning device 1 starts a cleaning operation. The predetermined time may be, for example, periodically, such as once a month, or when the total flow rate of wastewater flowing into the grit basin 9 or the total flow rate of wastewater discharged from the grit basin 9 reaches a certain amount. Note that the cleaning operation may be started while sand is being collected in the sand collection pit 94. The cleaning device 1 of this embodiment also serves as a sand separation device, so that sand is also discharged during the cleaning operation.

[0029] In the cleaning operation, the driving of the discharge device 5 is started first (step S10). While the discharge device 5 is being driven, the sand accumulated in the lower part of the discharge device 5 is transported obliquely upward along the discharge path of the discharge device 5. The sand transported by the screw conveyor 51 is transported while being drained 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 part of the discharge path of the discharge device 5 is discharged by being dropped downward from the drop port 52. After the discharge device 5 is started to be driven, the sand lifting pump 941 is then started to be driven. This start of driving 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 in the inner space X1 near the inner circumferential surface 3a of the container 3. The sand contained in the mixed water has a larger specific gravity than the impurities and wastewater, and is pressed against the inner peripheral surface 3a of the container 3 by centrifugal force, and gradually falls downward while rotating along the inner peripheral surface 3a. Meanwhile, in the radial center of the container 3, the impurities and wastewater from which the sand has been removed from the mixed water gather and generate an upward flow. Due to this upward flow, the impurities and wastewater gathered in the center are discharged from the discharge port 611 at the upper end of the container 3. The discharged impurities and wastewater pass through the delivery pipe 6 and are discharged from the other end 6a of the delivery pipe 6 into the grit basin 9. Since the other end 6a of the delivery pipe 6 is located below the discharge port 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 the like in the internal space X1 from the discharge port 611 and flows out into the grit basin 9 due to the principle of a siphon. This increases the amount of water dispensed, 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 peripheral surface 3a, and starts 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 the tangential direction of the discharge port 331 by the centrifugal force of the swirling flow. In Figs. 3 and 4, the discharge direction of the concentrated water is indicated by a curved arrow. If the storage tank 4 is empty when the discharge of the concentrated water starts, the tank liquid level WL2 in the storage tank 4 gradually rises. In addition, the sand contained in the storage liquid stored in the storage tank 4 settles toward the bottom of the storage tank 4 due to its own weight, and is deposited in the lower part of the carrying-out device 5. In addition, when the amount of deposited sand increases, the sand that does not fit in the lower part of the carrying-out device 5 is also deposited in the lower part of the storage tank 4. Among the impurities contained in the stored liquid, those with a low specific gravity will float in the wastewater, which is the supernatant liquid of the stored liquid, while those with a high specific gravity will slowly sink in the wastewater.

[0031] As shown in FIG. 3 and FIG. 4, when the tank liquid level WL2 rises and reaches a height position facing the discharge port 331 (YES in step S13), the wastewater, which is the supernatant liquid of the stored liquid in the portion facing the discharge port 331, is sucked into the discharge port 331 together with the floating impurities (step S14). The wastewater sucked into the discharge port 331 corresponds to an example of a liquid component. Hereinafter, the impurities sucked into the discharge port 331 and the wastewater are collectively referred to as the impurity-containing liquid component. In FIG. 4, the concentrated water discharged from the discharge port 331 is shown with cross-hatching in an enlarged view surrounded by a circle. In this enlarged view, the container 3, the tank liquid level WL2, and the concentrated water are shown with solid lines. As shown in this enlarged view, the concentrated water is discharged toward the outer periphery of the discharge port 331 by 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 therebetween, the discharge port 331 is connected to the tank liquid level WL2 by the concentrated liquid being discharged being connected to the stored liquid. In this state, the discharge port 331 is covered by the concentrated water being discharged and the tank liquid level WL2. Negative pressure is generated in the radial center portion of the discharge port 331 by the upward flow generated in the container 3. Due to this negative pressure, the supernatant liquid of the stored liquid near the radial center portion of the discharge port 331 and the impurities floating in the vicinity are 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 by the above-mentioned negative pressure can be said to be one aspect 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 in is indicated by a straight arrow. When the 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, the impurity-containing liquid component and air are sucked into the outlet 331 in an amount equal to or greater than the amount of concentrated water to be released. 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.In addition, even if the impurity-containing liquid component and air are sucked in from the discharge port 331 in an amount equal to or greater than the amount of concentrated water to be discharged, they can be sent out from the delivery port 611. In a state in which the impurity-containing liquid component and air are sucked in from the discharge port 331, a balanced state is formed in which the amount of concentrated water discharged from the discharge port 331 into the storage tank 4 and the amount of the impurity-containing liquid component sucked into the internal space X1 from the discharge port 331 are almost equal. The volume of the air sucked into the discharge port 331 is 1 / 5 or less of the volume of the impurity-containing liquid component. In this embodiment, a flange 332 is formed around the discharge port 331, which expands in the horizontal direction, so that air above the discharge port 331 is less likely to be sucked into the discharge port 331. In addition, the flange 332 suppresses the rippling of the tank liquid level WL2 near the discharge port 331. As a result, air is less likely to be sucked into the outlet 331, and the ratio of the impurity-containing liquid component sucked into the outlet 331 relative to air is increased. Furthermore, the concentrated water discharged from the outlet 331 is more likely to be discharged in an orderly manner by the flange 332. As a result, the sand contained in the concentrated water discharged from the outlet 331 is prevented from being mixed with the impurity-containing liquid component sucked from the center part of the outlet 331 in the radial direction. At the 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. Here, as described above, the concentrated water is discharged from the outlet 331 toward the outer periphery of the outlet 331, so that the sand contained in the concentrated water is less likely to be sucked in from the center part of the outlet 331. In addition, sand has a large specific gravity and is likely to settle early downward in the storage tank 4. For this reason, even if a strong upward flow is formed in the container 3 and the suction force generated at the discharge port 331 is strong, the amount of sand sucked into the container 3 is limited to an extremely small amount. Since this extremely small amount of sand has a high specific gravity compared to the impurity-containing liquid component, most of it is ejected from the upward flow toward the outer periphery in the container 3, swallowed by the swirling flow, and then released again from the discharge port 331 into the storage tank 4. As described above, air is also sucked in from the discharge port 331, so the upward flow generated in the center of the container 3 is a fluid flow with a low specific gravity that is mixed with the sucked in air.Therefore, the difference in specific gravity between the fluid that mainly constitutes the upward flow and the sand becomes larger, and the sand with a higher specific gravity is more likely to be pushed out toward the outer periphery. Also, the stored liquid stored 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 component of the stored liquid to rise up and float in the stored liquid.

[0032] In addition, when the amount of mixed water flowing into the container 3 is less than 2.0 m3 / min, the amount of the impurity-containing liquid component sucked into the discharge port 331 becomes 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, so the amount of concentrated water discharged from the discharge port 331 decreases. That is, the resistance due to the reduction in the cross-sectional area of ​​the internal space X1 in the throttle section 32 and the water pressure of the stored liquid applied to the discharge port 331 combine to make it difficult for the concentrated water to be discharged from the discharge port 331. Then, as the tank liquid level WL2 rises, the water pressure of the stored liquid applied to the discharge port 331 increases, so the amount of concentrated water discharged from the discharge port 331 decreases, and the amount of water delivered from the delivery port 611 increases. In addition, as described above, when the liquid fills the inside of the delivery pipe 6, the delivery water acts to flow out of the delivery port 611 into the grit basin 9 due to the principle of a siphon, so the amount of delivery water delivered from the delivery port 611 increases further. As a result, the amount of impurity-containing liquid components sucked into the discharge port 331 increases, and the tank liquid level WL2 drops to a position facing the discharge port 331. That is, during the period when the tank liquid level WL2 is dropping, the impurity-containing liquid components are sucked in in an amount equal to or greater than the amount of concentrated water discharged from the discharge port 331. In this way, when the mixed water flowing into the container 3 is reduced, an inexpensive sand pump 941 can be used, and the amount of electricity used by the sand pump 941 can be reduced. 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, but even in this state, the liquid is stored 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 covering 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 if the water pressure of the stored liquid applied to 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 driving the sand lifting pump 941 (YES in step S15), the driving of the sand lifting pump 941 is stopped (step S16). This first predetermined time is the time during which most of the sand collected in the sand collection pit 94 can be sucked up by the sand lifting pump 941, and is a time set appropriately according to the capacity of the sand lifting pump 941 and the amount of sand that can be collected in the sand collection pit 94. By stopping the sand lifting pump 941, the inflow of mixed water into the container 3, the discharge of concentrated water into the storage tank 4, the suction of impurity-containing liquid components, and the discharge of the discharge water are also stopped. The above-described steps S11 to S16 correspond to an example of the inflow process. Moreover, steps S14 to S16 correspond to an example of the discharge and suction process.

[0034] When the second predetermined time has elapsed since the driving of the sand lifting pump 941 has stopped (YES in step S17), the driving 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 total time of the time 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 for the sand to be transported from the lower part of the discharge device 5 to the drop port 52. Note that instead of determining whether the second predetermined time has elapsed or not, 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 to determine whether the sand in that part has run out. This completes the operation of the cleaning device 1. During the operation of the discharge device 5, the tank liquid level WL2 is at a position that is approximately aligned with the discharge port 331, so that even if the discharge path is short, the sand can be transported while being drained. Since the discharge path extends obliquely upward, the width and height of the discharge device 5 can be shortened by shortening the discharge path. As a result, the cleaning device 1 can be made compact. According to the cleaning device 1 of this embodiment, not only is the sewage and impurities separated from the sand from the mixed water flowing into the container 3 and the impurities and sewage are discharged from the outlet 611, but the impurities and liquid components are sucked up from the stored liquid stored in the storage tank 4 while the impurities and sewage are discharged from the outlet 611, so that clean sand without impurities can be left in the storage tank 4. In addition, the sand in the container 3 is prevented from reaching the outlet 611, so that the sand can 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 device 1 of the first modification is different from the cleaning device 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 state. An outlet 451 is formed at the tip of the cleaning water supply pipe 45. The outlet 451 is disposed in the storage tank 4 at the lower end portion of the storage tank 4. The outlet 451 is disposed below the discharge port 331. The outlet 451 is for generating 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. The purified water is discharged from the outlet 451 by opening the valve 452. As a result, about 0.2 m3 / min of purified water is injected into the storage tank 4. This purified water corresponds to an example of a fluid. In this first modification, about 2.2 m3 / min of discharge water is discharged from the delivery port 611. In the first modification, the valve 452 is a manual valve, but may be an electric valve. The discharge port 451 discharges purified water toward the sand accumulated at the lower end of the storage tank 4. This configuration not only generates a liquid flow in the stored liquid, but also lifts up the accumulated sand and impurities, so that the impurities buried in the sand can be raised. This makes it easier for the impurities to be sucked into the discharge port 331, so that a high cleaning effect can be obtained. When the amount of purified water discharged from the delivery port 611 is increased or the discharge pressure is increased, the sand also flies up to the vicinity of the discharge port 331 and is easily sucked into the discharge port 331. However, in this cleaning device 1, most of the sand sucked into the container 3 is ejected from the upward flow toward the outer periphery in the container 3, is swallowed by the swirling flow, and is discharged again from the discharge port 331 into the storage tank 4. Therefore, in this cleaning device 1, by increasing the amount of purified water discharged from the delivery port 611 or increasing the discharge pressure, it is possible to obtain a high cleaning effect while suppressing sand from being sent out 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. Also, there may be multiple delivery ports 451, and the delivery ports 451 may be provided below and above the discharge port 331.In particular, when there is a surplus in the capacity to suck impurity-containing liquid components into the container 3 from the discharge port 331 and a lot of air is being sucked in from the discharge port 331, it is preferable to increase the number of discharge ports 451 or the amount of purified water discharged from the discharge port 451 to increase the amount of purified water supplied to the storage tank 4. In this way, more impurities can be stirred up, and the amount of impurity-containing liquid components sucked into the container 3 from the discharge port 331 can be increased, thereby improving the cleaning capacity of the cleaning device 1.

[0038] The injection of purified water into the storage tank 4 is performed between step S11 (start of driving the sand pump 941) and step S16 (stop of driving the sand pump 941) shown in FIG. 5, that is, during the inflow process. However, the injection may be started before step S11, and the tank liquid level WL2 may be made to face the discharge port 331 in advance. In this case, the suction of the impurity-containing liquid component is started at the same time as the concentrated water is discharged. After step S14, the height position of the tank liquid level WL2 and the height position of the discharge port 331 are almost the same position. The injection of purified water into the storage tank 4 may be performed after step S11, for example, between step S14 (start of suction of the impurity-containing liquid component) and step S16 (stop of driving the sand pump 941), that is, during the discharge and suction process. This process of injecting purified water into the storage tank 4 corresponds to an example of an injection process. By injecting purified water, the cleaning effect of the cleaning device 1 can be improved.

[0039] Also, a fine bubble water generator (not shown) may be provided to inject fine bubble water into the storage tank 4 instead of purified water. The fine bubble water is a liquid containing fine bubbles of 100 μm or less. The 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, the fine bubble water may be a liquid containing both microbubbles and ultrafine bubbles. The cleaning effect of the cleaning device 1 can be further improved by using fine bubble water. 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, the differences from the first modified example shown in Fig. 6 will be mainly explained.

[0041] As shown in FIG. 7, the cleaning device 1 of the second modification is different from the cleaning device 1 shown in FIG. 6 in that a cleaning water supply pipe 45 is connected to the discharge device 5. The cleaning water supply pipe 45 penetrates the wall on the upstream side in the discharge direction of the discharge device 5 in a watertight state. The discharge port 451 is disposed in the discharge device 5 at the lower end part of the discharge device 5. Moreover, the discharge port 451 is disposed below the discharge port 331. The discharge port 451 discharges purified water upward. In this second modification, the discharge port 451 discharges purified water from below the sand accumulated in the discharge device 5 toward the upper side, so that a lot of sand and impurities can be stirred up. As described above, fine bubble water may be discharged from the discharge port 451 instead of purified water. Moreover, gas may be discharged from the discharge port 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 discharge 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 explaining the third modified example, differences from the first modified example shown in Fig. 6 will be mainly explained.

[0043] As shown in FIG. 8, the cleaning device 1 of the third modified example is different from the cleaning device 1 shown in FIG. 6 in that the cleaning water supply pipe 45 is connected to the discharge pipe 55. The cleaning water supply pipe 45 is connected to the discharge pipe 55 on the screw conveyor 51 side of the 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 part of the screw conveyor 51 in the discharge device 5 where sand is piled up. Therefore, the supplied purified water is discharged from the side toward the inside of the discharge device 5 from the connection part between the discharge pipe 55 and the discharge device 5. That is, in this third modified example, the connection part between the discharge pipe 55 and the discharge device 5 becomes the discharge port 451. In FIG. 8, the discharge port 451 is shown slightly protruding into the discharge device 5 for easy understanding. The discharge port 451 is disposed below 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, so that a large amount of sand and impurities can be stirred up. In this third modified example, fine bubble water may 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 end 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 is different from the washing device 1 and the sedimentation basin 9 shown in FIG. 1 in that the trough 92, the sand collecting nozzle 93, the sand collecting pit 94, the pond bottom slope 95, the sand lifting pump 941, and the sand lifting pipe 942 are not present, but instead a grab bucket type sand lifting device 96 is provided, and treated water is allowed to flow into the container 3. The grab bucket type sand lifting device 96 is installed in the sedimentation basin 9. The grab bucket type sand lifting device 96 includes a rail 961, a movable winch 962, and a grab bucket 963. The rail 961 is supported by a support 9611 erected on the ground portion of the sedimentation basin 9. The rail 961 is hung over the entire length of the sedimentation basin 9 in the longitudinal direction. The movable winch 962 is configured to be movable along the rail 961. The grab bucket 963 is suspended from the movable 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 for supplying treated water, which will be 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 the amount of sand accumulated on the bottom of the settling basin 9 shown in FIG. 9 reaches a certain amount, the grab bucket type sand lifting device 96 is operated to dump the sand, which is accumulated on the bottom of the settling basin and contains impurities, into the storage tank 4. After the dumping, the tank lid 42 is closed and the cleaning device 1 starts the cleaning operation. If the container 3 is installed by providing an installation tool for placing the container 3 at the position shown in FIG. 3 or FIG. 4, the tank lid 42 may be closed at any time. In that case, the tank lid 42 may be omitted. In the cleaning operation, first, the supply of treated water into the container 3 is started. The treated water is water treated in a sewage treatment facility, and is supplied into the container 3 by being pumped into the treated water pipe 97 by a pump. Instead of the treated water, wastewater before the treatment is completed may be supplied from a settling basin or the like, or tap water or natural water may be supplied. In other words, water obtained from a place 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. The supply of treated water into the vessel 3 is started, and thus the inflow of treated water into the vessel 3 is started (step S21). Since the treated water flows in from the tangential direction of the inner circumferential surface 31a of the cylindrical portion 311, a swirling flow of treated water is formed in the internal space X1 near the inner circumferential surface 3a of the vessel 3. Due to this swirling flow, the inflowing treated water gradually moves downward while swirling along the inner circumferential surface 3a. Meanwhile, an upward flow is generated in the radial center portion of the vessel 3. Due to this upward flow, a certain amount of the inflowing treated water is sent out as it is from the delivery outlet 611 at the upper end of the vessel 3. As shown in FIG. 9, the sent out treated water passes through the delivery pipe 6 and is discharged from the other end 6a of the delivery pipe 6 toward the grit basin 9.

[0048] In the internal space X1, a portion of the treated water gradually moves downward while swirling along the inner peripheral surface 3a, and reaches the discharge port 331 and starts to be discharged from the discharge port 331 (step S22). A portion of the treated water is discharged from the discharge port 331 in the tangential direction of the discharge port 331 by the centrifugal force of the swirling flow. Since sand containing impurities has accumulated in the storage tank 4, a portion of the discharged treated water falls onto the sand and forms a tank liquid level WL2 in the storage tank 4. The tank liquid level WL2 gradually rises as a portion of the treated water is discharged. In this second embodiment, the sand containing impurities that was originally put into the storage tank 4 and a portion of the treated water discharged 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 in the portion facing the discharge port 331 is sucked in from the center of the discharge port 331 (step S24). In addition, the stored liquid stored in the storage tank 4 is stirred by the discharged 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. In addition, 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, the impurity-containing liquid component and air are sucked in from the outlet 331 in an amount equal to or greater than a portion of the discharged treated water. In the state in which the impurity-containing liquid component and air are sucked in from the outlet 331, a balanced state is formed in which the amount of treated water discharged from the outlet 331 into the storage tank 4 and the amount of impurity-containing liquid component sucked into the internal space X1 from the outlet 331 are almost equal. Here, the sand contained in the stored liquid is stirred to some extent, but since its specific gravity is greater than that of the treated water, it rarely rises to the vicinity of the tank liquid level WL2. Therefore, even if the suction force generated at the outlet 331 is strong, only a small amount of sand is sucked into the container 3. Even if it is sucked in, since the specific gravity of the sand is greater than that of the impurity-containing liquid component, most of it is repelled from the upward flow toward the outer periphery in the container 3 and swallowed by the swirling flow, and is released again from the outlet 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 m3 / min, the tank liquid level WL2 may rise above the discharge port 331. However, once the tank liquid level WL2 has risen, it will drop to a position facing the discharge port 331 due to the water pressure applied to 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 a time during which impurities mixed in the sand in the storage tank 4 can be sucked up together with the liquid component of the stored liquid, and may be a time set in advance based on experimental results, or may be a time input by an operator according to the amount of sand put into the storage tank 4 and the degree of impurities mixed in. By stopping the supply of treated water, the inflow of treated water into the container 3, the discharge of a part of the treated water into the storage tank 4, the suction of the liquid component containing impurities, and the discharge of the discharge water are also stopped. Steps S21 to S26 described above correspond to an example of the inflow process. Moreover, steps S24 to S26 correspond to an example of the discharge and suction process. When the supply of treated water is stopped, the drive of the discharge device 5 is started (step S27). When a fourth predetermined time has elapsed since the start of driving the carry-out device 5 (YES in step S28), the drive of the carry-out device 5 is stopped (step S29). This fourth predetermined time is a time required for all the sand accumulated in the lower part of the carry-out device 5 to be transported to the drop port 52 and discharged, and may be a time set in advance in consideration of an expected amount of accumulated sand, or may be a time input by an operator according to the amount of sand charged into the storage tank 4. Note that instead of determining whether the fourth predetermined time has elapsed or not, a sand presence / absence sensor that detects the presence or absence of sand in the lower part of the carry-out device 5 may be provided in the carry-out device 5, and it may be determined whether the sand in that part has run out or not. Steps S27 to S29 described above correspond to an example of a discharge process. Note that the drive of the carry-out device 5 may be started before the supply of treated water is stopped (step S26), but since there is a risk that sand containing impurities before cleaning may be discharged from the drop port 52, it is preferable to drive the carry-out device 5 after the supply of treated water is stopped (after cleaning is completed) in this second embodiment. In the 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, since the sand is prevented from reaching the delivery port 611, it is also possible to prevent the sand 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 device 1 of the third embodiment differs from the cleaning device 1 shown in FIG. 6 in the structure of the bottom of the storage tank 4 and in that a belt gate 7 is provided instead of the discharge device 5. This belt gate 7 corresponds to an example of a discharge unit. An opening 4a is formed at the bottom of the storage tank 4. In FIG. 11, this opening 4a is blocked by a belt gate 7 shown by a solid line. The opening 4a of the storage tank 4 opens in a position tilted 3° upward from the right side to the left side of the figure. The belt gate 7 is disposed at the lower end portion of the storage tank 4 in a position tilted 3° upward like the opening 4a. However, the opening 4a and the belt gate 7 may be disposed horizontally. In a state in which the opening 4a is blocked by the belt gate 7, the stored liquid stored in the storage tank 4 is prevented from being discharged from 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 has a plurality of rollers 71 extending in a direction perpendicular to the paper surface of FIG. 11 and a belt 72 wound around the plurality of rollers 71. Among the plurality of rollers 71, the rollers 71 arranged at both the left and right ends in FIG. 11 are for driving, and by driving these driving rollers 71, the belt gate 7 moves from the closed state position to the left. Hereinafter, the direction in which the belt gate 7 moves from the closed state position is referred to as the opening direction. Note that since the belt gate 7 is well known, detailed explanations are omitted, and the belt gate 7 is shown in a simplified form in the drawings, and the driving device, frame, etc. are omitted. When the belt gate 7 moves from the closed state position to the opening direction, all of the openings 4a are opened, as shown by the dashed line in FIG. 11. When the belt gate 7 moves in the opening direction, the sand accumulated on the belt gate 7 is discharged from the opening 4a of the storage tank 4 together with the liquid component of the stored liquid to the outside 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 to the outside of the storage tank 4. Hereinafter, the state of the belt gate 7 in which all of the openings 4a are open is referred to as the open state. The belt gate 7 moves to the right from the open state shown 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 is referred to as the closed 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 contained in the storage tank 4 is discharged outside the storage tank 4.

[0053] In the third embodiment, the cleaning water supply pipe 45 penetrates the side wall 41 of the storage tank 4 in a watertight manner. The discharge port 451 is disposed below the discharge port 331 so as to discharge the purified water horizontally toward the lower end portion of the storage tank 4. In other words, the discharge port 451 discharges the 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, first, the sand lifting pump 941 is started to be driven. This starts the inflow of mixed water into the container 3 (step S31). Steps S31 to S36 are the same as steps S11 to S16 shown in FIG. 5 except that the discharge device 5 is not driven, so the explanation is omitted. Steps S31 to S36 correspond to an example of the inflow process. Steps S34 to S36 correspond to an example of the discharge and suction process. Furthermore, in this third embodiment, similar to the cleaning device 1 shown in FIG. 6, during steps S31 to S36, that is, 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, so that a lot of sand and impurities can be lifted up. In addition, a liquid flow can be generated in the stored liquid stored in the storage tank 4. The 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 the movement of the belt gate 7, the sand accumulated on the belt gate 7 is discharged to the outside of the storage tank 4. This step S37 corresponds to an example of a discharge step. Note that, before the storage tank 4 is opened, a truck is made to wait under the storage tank 4. The sand discharged from the storage tank 4 falls into the truck bed or a container provided on the bed and is carried by the truck. After the sand in the storage tank 4 is 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. With the cleaning device 1 of the third embodiment, the same effect as that of the cleaning device 1 shown in FIG. 6 can be obtained.

[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 the present embodiment, the cleaning device 1 is installed in the grit basin 9, but the cleaning device 1 may be installed in a place other than the grit basin. In addition, the cleaning device 1 is used to clean sand, but the cleaning device 1 may clean other objects to be cleaned, such as soil and sand. Furthermore, a discharge mechanism other than the screw conveyor 51 and the belt gate 7 may be used as the discharge section.

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

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

[0060] The cleaning device described above includes a container having an inlet through which liquid flows and a discharge port through which a swirling flow is generated in the flowing liquid and a part of the liquid is discharged, a storage tank for storing a liquid containing impurities and objects to be cleaned, facing the discharge port; a discharge section for discharging the object to be cleaned contained in the liquid stored in the storage tank, the container has a constriction portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner circumferential 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 liquid flows and a discharge port through which a swirling flow is generated in the flowing liquid and a part of the liquid is discharged, a storage tank for storing a liquid containing impurities and objects to be cleaned, facing the discharge port; a discharge section for discharging the object to be cleaned contained in the liquid stored in the storage tank, the container has a constriction portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner circumferential 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, and negative pressure is generated 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 object to be cleaned contained in the stored liquid may also be sucked into the container, but since the object to be cleaned has a large specific gravity compared to the impurities and the liquid components of the stored liquid, the object to be cleaned sucked into the container is likely to be ejected from the upward flow and released again into the storage tank. On the other hand, the impurities in the storage tank have a small specific gravity, so they fly up in the storage tank and are likely to be sucked in from the outlet, and the impurities sucked into the container are likely to rise on the upward flow in 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 outside 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 outlet may be disposed in the storage tank. In addition, the outlet may be covered by the stored liquid when connected to the stored liquid in the storage tank. In addition, the outlet may be connected to the liquid level of the stored liquid in the storage tank. In a state where the outlet is connected to the liquid level of the stored liquid in the storage tank, the outlet and the liquid level may be slightly separated, and the periphery of the outlet may be covered by a part of the liquid discharged from the outlet and the liquid level, or the liquid level may be in contact with the outlet. Furthermore, the outlet may be submerged in the stored liquid stored in the storage tank. In a state where the outlet is submerged in the stored liquid stored in the storage tank, the stored liquid in the part covering the outlet faces the outlet. In addition, the liquid flowing into the container may be wastewater containing impurities and objects to be cleaned. The discharge unit may be a conveyor for transporting the objects to be cleaned, or a gate or valve capable of opening and closing the bottom side portion of the storage tank. The discharge unit may also be connected to the lower end of the storage tank. The impurities may have a lower specific gravity than the liquid component of the stored liquid, and the objects to be cleaned may have a higher specific gravity than the liquid component.

[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 lower than the discharge port.

[0065] The liquid flow can lift up impurities that settle to the bottom side of the storage tank or impurities 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 fly upward and be easily sucked into the container through the outlet, but in this cleaning device, the objects to be cleaned that have been sucked into the container as described above are easily released back into the storage tank. Therefore, in this cleaning device, a high cleaning effect can be obtained while suppressing the outflow of the objects to be cleaned together 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. 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 the 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 discharge 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 discharge port. [Explanation of symbols]

[0069] 1 Cleaning equipment 3 containers 4. Reservoir 5 Unloading device 32 Squeezing 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 swirling flow is generated in the flowing liquid and a portion of the liquid is discharged; a storage tank for storing a liquid containing impurities and objects to be cleaned, facing the discharge port; 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 constriction portion between the inlet and the outlet, in which a cross-sectional area of ​​an internal space defined by an inner circumferential 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 cleaning device according to claim 1, wherein the discharge port is connected to the liquid stored in the storage tank.

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