Cleaning water treatment system

Abstract

To provide a cleaning water treatment system capable of easily removing in a short period of time adhered materials derived from fresh concrete on the inner walls of containers such as drums of mixer trucks, or the adhered materials on the flow paths and containers through which cleaning water flows after cleaning, and capable of preventing the adhered materials from being generated and adhered on the inner walls of these containers and pipes and flow paths, and the like.SOLUTION: A cleaning water treatment system has a pipe (10) through which cleaning water used for cleaning a container containing ready-mixed concrete or inside a pipe into which ready-mixed concrete is poured, or cleaning water after such cleaning is poured, a coil (C1, C2) wound around at least one part of the outer circumference of the pipe, and an alternating current supply device (20) for supplying an alternating current to the coil, the alternating current having a frequency that is continuously and repeatedly increased and decreased within at least a part of the frequency range from 100 Hz to 10 kHz, wherein the alternating current is applied to the coil while the cleaning water is flowing through the pipe.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wash water treatment system, and is suitably applied to the treatment of wash water for washing the inside of the drum of a mixer truck, for example. [Background technology]

[0002] In a ready-mix concrete manufacturing plant (concrete plant), ready-mix concrete is manufactured by mixing the materials of ready-mix concrete, such as cement, aggregates (sand and gravel), water, and admixtures, in a mixer. The ready-mix concrete manufactured in this way is poured from a loading hopper into the drum of a mixer truck, and the mixer truck heads to the site where the ready-mix concrete will be used. After arriving at the site, the mixer truck uses the ready-mix concrete in the drum and returns to the ready-mix concrete manufacturing plant. Then, in a wash water treatment plant attached to the ready-mix concrete manufacturing plant, the supernatant water in the supernatant water tank is poured into the drum from the mixer truck's hopper as wash water, and the ready-mix concrete left in the drum (hereinafter sometimes referred to as "residual concrete") is washed (for example, see Non-Patent Document 1). Here, the supernatant water is the water after the residual concrete treatment. The wash water used to wash the inside of the drum passes through a car wash chute, a vibroscreen, a water collection tank, a sand cyclone, a crush fire, a sludge tank, etc., and is finally returned to the supernatant water tank.

[0003] A liquid treatment device for preventing scale formation and / or scale adhesion is known, which involves winding a solenoid coil around a pipe through which liquid flows and passing an alternating current whose frequency changes continuously and repeatedly in a frequency range of approximately 700 to 3000 Hz through the coil, thereby preventing scale formation on the inner wall of the pipe and removing scale that has adhered to the inner wall of the pipe (Patent Document 1).Also known is a tap water treatment device, which involves winding a solenoid coil around a water pipe and passing an alternating current whose frequency changes continuously and repeatedly in a frequency range of 3.6 to 7.5 kHz through the coil, thereby preventing scale formation on the inner wall of the water pipe and removing scale that has adhered to the inner wall of the water pipe, and has already been put to practical use (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 5,074,998 [Patent Document 2] Specification of Utility Model Registration No. 3224220 [Non-patent literature]

[0005] [Non-Patent Document 1] [Retrieved July 31, 2023], Internet〈URL:https: / / prod.kiw.co.jp / kkplant / mizu / 〉 [Non-Patent Document 2] [Retrieved July 31, 2023], Internet〈URL:https: / / www.nr-mix.co.jp / new_nama / blog / _kiwar2.html 〉 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even after the inside of the drum of a mixer truck is washed with wash water, hard, solidified material originating from the ready-mixed concrete still adheres to the inner wall of the drum. Furthermore, the same hard, solidified material also adheres to the car wash chute, vibroscreen, water collection tank, sand cyclone, crusher, and other components through which the wash water used to wash the inside of the drum passes. This solidified material is generally removed using a chisel-shaped tool called a scraper, but this is not only time-consuming and labor-intensive, but is also often difficult to remove (see, for example, Non-Patent Document 2).

[0007] Therefore, the problem that this invention aims to solve is to provide a wash water treatment system that can easily remove, in a short period of time, solidified materials derived from ready-mixed concrete that have adhered to various containers that store ready-mixed concrete inside, such as the drums of a mixer truck, or to the inner walls of pipes through which ready-mixed concrete is poured, or solidified materials derived from ready-mixed concrete that have adhered to channels or containers through which washing water flows after washing, and that can prevent the above-mentioned solidified materials from being generated and adhering to the inner walls or channels of these containers or pipes. [Means for solving the problem]

[0008] The present inventors have conducted intensive research for many years with the aim of developing a technology to solve the above problems, and as a result, have found that a new effect can be obtained by winding a coil similar to the coil used in the tap water treatment device described in Patent Document 2 around a pipe for passing washing water used to wash the inside of the drum of a mixer truck or washing water after washing, passing an alternating current through the coil using a device similar to the alternating current supply device described in Patent Document 2 while passing washing water through the pipe, and supplying washing water from the pipe into the drum of the mixer truck to perform washing, thereby easily removing, in a short period of time, the solidified matter derived from the ready-mixed concrete attached to the inner wall of the drum, and further, solidified matter derived from the ready-mixed concrete attached to various devices through which the washing water flows after the inside of the drum is washed, and further, by conducting further research based on this finding, the present invention has been devised. As far as the present inventors know, the achievement of such an effect has not been reported so far. The reason for the above-mentioned effect is currently being elucidated.

[0009] That is, in order to solve the above problems, the present invention provides: Washing water used for washing the inside of a container in which fresh concrete is stored or a pipe in which fresh concrete is poured, or a pipe in which the washing water after said washing is poured; a coil wound around at least one portion of the outer circumferential surface of the tube; An alternating current supply device for supplying an alternating current having a frequency that is repeatedly increased and decreased continuously in at least a part of a frequency range of 100 Hz to 10 kHz to the coil; having The cleaning water treatment system is configured to cause the AC current to flow through the coil by the AC current supply device while causing the cleaning water to flow through the pipe.

[0010] The container in which the ready-mixed concrete is stored is typically, but not limited to, the drum of a mixer truck or a mixer in a ready-mixed concrete manufacturing plant. The pipe through which the ready-mixed concrete flows is, for example, but not limited to, a transport pipe for ready-mixed concrete in a ready-mixed concrete manufacturing plant. The pipe through which the wash water or the wash water after washing flows is typically, but not limited to, a pipe that supplies supernatant water and / or a pipe that connects a water collection tank and a sand cyclone in a wash water treatment plant attached to the ready-mixed concrete manufacturing plant.

[0011] The at least a part of the frequency range is typically included in a frequency range of 4.5 kHz to 8 kHz, for example, a frequency range of 4.5 kHz to 8 kHz. The frequency of the AC current is typically increased and decreased linearly, but is not limited thereto, and may be increased and decreased nonlinearly. The AC current typically repeats increasing and decreasing the frequency multiple times per second within at least a part of the frequency range. The AC current sweeps the frequency from 100 Hz to 10 kHz, for example. The waveform of the AC current is not particularly limited and is selected as needed, but is typically a square wave. The current value of the AC current is selected as needed, but is generally 1 mA to 2.5 A (2500 mA), typically 0.5 A to 2.5 A. It is sufficient that the coil is wound at least at one place on the outer circumferential surface of the tube, but it may be wound at multiple places. The number of turns in the coil is selected appropriately depending on the diameter of the pipe, etc., but since a better effect tends to be obtained when the strength of the magnetic field generated by passing an alternating current through the coil is relatively large, the number of turns in the coil is generally selected to be between 10 and 20. Effect of the Invention

[0012] According to this invention, by passing an alternating current whose frequency continuously increases and decreases in at least a part of the frequency range of 100 Hz to 10 kHz through a coil while passing cleaning water used to clean the inside of a container that holds ready-mixed concrete or a pipe through which ready-mixed concrete is poured, or cleaning water through a pipe for supplying the cleaning water after cleaning, it is possible to easily remove, in a short period of time, solidified substances derived from ready-mixed concrete that have adhered to the inner walls of the container or pipe, or solidified substances derived from ready-mixed concrete that have adhered to flow paths or containers through which the cleaning water after cleaning passes, using a simple method, and it is possible to realize a cleaning water treatment system that can prevent the above-mentioned solidified substances from being generated and adhering to the inner walls or flow paths of these containers or pipes. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing a cleaning water treatment system according to an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing a coil wound around a pipe in a cleaning water treatment system according to an embodiment of the present invention and an alternating current supply device for supplying an alternating current to the coil. [Figure 3A] 2 is a schematic diagram showing an example of a waveform of an alternating current applied to a coil by an alternating current supply device in a cleaning water treatment system according to an embodiment of the present invention. FIG. [Figure 3B] 1 is a schematic diagram showing an example of a frequency spectrum of an alternating current applied to a coil by an alternating current supply device in a cleaning water treatment system according to an embodiment of the present invention. [Figure 3C] 1 is a schematic diagram showing an example of a measured frequency spectrum of an alternating current applied to a coil by an alternating current supply device in a cleaning water treatment system according to an embodiment of the present invention; [Figure 4] 1 is a schematic diagram showing a specific example of a wash water treatment plant to which a wash water treatment system according to an embodiment of the present invention is applied. [Diagram 5]5 is a photograph in lieu of a drawing showing a state in which coils are wound around pipes 40 and 100 in an actual wash water treatment plant having the configuration shown in FIG. 4 and these coils are connected to an alternating current supply device. [Figure 6A] 5 is a photograph in lieu of a drawing showing the state of the car wash chute 60 when the coil and the AC supply device are installed for the pipes 40, 100 in the actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 6B] 5 is a photograph in lieu of a drawing showing the state of the car wash chute 60 about two months after the coil and AC supply device were installed on the pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 7A] 5 is a photograph in lieu of a drawing showing the state of a vibroscreen 70 when coils and an AC supply device are installed on pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 7B] 5 is a photograph, substituted for a drawing, showing the state of the vibroscreen 70 about two months after the coils and AC supply device were installed on the pipes 40, 100 in the actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 8A] 5 is a photograph in lieu of a drawing showing the state of the water collection tank 90 when a coil and an AC supply device are installed for the pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 8B] 5 is a photograph in lieu of a drawing showing the state of the water collection tank 90 about two months after the installation of coils and alternating current supply devices for the pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 9A] 5 is a photograph in lieu of a drawing showing the state of a gravel recovery conveyor 80 when coils and an AC supply device are installed for pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 9B] 5 is a photograph in lieu of a drawing showing the state of the gravel recovery conveyor 80 about two months after the coils and AC supply device were installed on the pipes 40, 100 in the actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 10A] 5 is a photograph in lieu of a drawing showing the state of a crashfire 120 when a coil and an AC supply device are installed for pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 10B] 5 is a photograph in lieu of a drawing showing the state of a crash fire 120 about two months after the installation of a coil and an AC power supply device for pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 11A] 5 is a photograph in lieu of a drawing showing the state of a hopper nozzle of a sand cyclone 110 when a coil and an AC supply device are installed for pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. [Figure 11B] 5 is a photograph in lieu of a drawing showing the state of the hopper nozzle of the sand cyclone 110 about two months after the installation of a coil and an AC supply device for the pipes 40, 100 in an actual wash water treatment plant having the configuration shown in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, modes for carrying out the invention (hereinafter referred to as "embodiments") will be described.

[0015] <One embodiment> [Cleaning water treatment system] Fig. 1 shows a wash water treatment system according to one embodiment. As shown in Fig. 1, this wash water treatment system has a pipe 10 through which wash water used for washing the inside of the drum of a mixer truck, the inside of a mixer in a ready-mix concrete manufacturing plant, the inside of a ready-mix concrete transport pipe, etc., or the wash water after said washing flows, solenoid coils C1 and C2 wound around the outer periphery midway through the pipe 10, and an AC current supply device 20 for passing an AC current through the coils C1 and C2.

[0016] The AC current supply device 20 is connected to coils C1 and C2 wound around the outer circumferential surface of the pipe 10 by a cable C. The coils C1 and C2 are formed by winding the cable C in a spiral shape. The AC current supply device 20 is provided with a power cable 21 for supplying AC 100V. The details of the coils C1 and C2 wound around the outer circumferential surface of the pipe 10 are shown in FIG. 2. As shown in FIG. 2, in this case, the cable C is provided between the coils C1 and C2 in parallel with the pipe 10, and the winding directions of the coils C1 and C2 on the outer circumferential surface of the pipe 10 are the same. The AC current flowing through the coils C1 and C2 sweeps the frequency from 100Hz to 10kHz, and has a square wave shape. In this case, the frequency is linearly increased and decreased multiple times per second, typically 2 to 5 times (for example, 3.5 times) in a part of the frequency range of 100Hz to 10kHz (frequency range f1 to f2), and this is repeated. The frequency range of f1 to f2 is typically 4.5 kHz to 8 kHz. FIG. 3A shows an example of the waveform of this AC current. As shown in FIG. 3A, in the frequency range of f1 to f2, the maximum current value is set higher than in the frequency range of 100 Hz to f1 and the frequency range of f2 to 10 kHz. The maximum current value in the frequency range of f1 to f2 is set, for example, 2 to 3 times higher than the maximum current value in the frequency range of 100 Hz to f1 and the frequency range of f2 to 10 kHz, but is not limited thereto. FIG. 3B shows an example of a frequency spectrum when an AC current is passed through the coils C1 and C2 in this way. As shown in FIG. 3B, the AC current flowing through the coils C1 and C2 has almost the same maximum current value in the frequency range of f1 to f2. FIG. 3C shows an example of a measured frequency spectrum. The frequency range of f1 to f2 is 4.5 kHz to 8 kHz. The vertical axis of this frequency spectrum represents the sound pressure when a pickup for measuring sound pressure is attached to the side of the pipe 10 around which coils C1 and C2 are wound and the electromagnetic noise generated by AC current flowing through coils C1 and C2 is measured, and corresponds to the maximum current value of the AC current.

[0017] [How to use the cleaning water treatment system] The power cable 21 of the AC current supply device 20 is inserted into an AC 100V outlet, and the switch of the AC current supply device 20 is turned on. Then, an AC current is passed through the coils C1 and C2 while the wash water is made to flow through the piping 10 by a pump (not shown), thereby treating the wash water. The piping 10 is, for example, a piping for supplying supernatant water after residual concrete treatment to the drum of a mixer truck in a wash water treatment plant attached to a ready-mix concrete manufacturing factory, or a piping for connecting a water collection tank into which wash water is passed after washing to a sand cyclone.

[0018] According to the wash water treatment system of this embodiment, wash water or post-wash wash water is treated by passing a predetermined AC current through coils C1 and C2 wound around a pipe 10 by an AC current supply device 20, and the thus treated wash water is used to wash the inside of the drum of a mixer truck, the inside of a mixer in a ready-mix concrete manufacturing plant, the inside of a pipe through which ready-mix concrete is poured, or a flow path or container through which the post-wash wash water flows. This makes it possible to easily remove in a short time the solidified matter derived from the fresh concrete adhering to the inner walls of the drum of a mixer truck or the mixer in a ready-mix concrete manufacturing plant, the inner walls of a pipe through which ready-mix concrete is poured, or the solidified matter derived from the fresh concrete adhering to the flow path or container through which the post-wash wash water flows, and also makes it possible to prevent the above solidified matter from being generated and adhering to the inner walls or flow paths of these containers or pipes. Moreover, this wash water treatment system can be easily constructed, since it is sufficient to simply wind coils C1 and C2 around a pipe 10 for supplying wash water or post-wash wash water in a conventionally used general wash water treatment plant, and connect the AC current supply device 20 to the coils C1 and C2.

[0019] A specific example of a wash water treatment plant to which the wash water treatment system according to this embodiment is applied will be described.

[0020] FIG. 4 shows an outline of a typical wash water treatment plant attached to a ready-mix concrete manufacturing plant (concrete plant). As shown in FIG. 4, the supernatant water 31 stored in the supernatant water tank 30 is passed through a pipe 40 by a pump (not shown) and supplied as wash water to a hopper 52 attached to a drum 51 of a mixer truck 50 that has finished transporting ready-mix concrete. The wash water supplied to the drum 51 for washing passes through a scoop 53 and is discharged from the chute at the tip of the scoop to a car wash chute 60. The wash water flowing through the car wash chute 60 is supplied to a vibro screen 70, where the gravel in the wash water is collected. The collected gravel containing moisture is transferred to a gravel collection conveyor 80 and finally dropped on the ground. Reference numeral 81 denotes the gravel thus dropped. The water that passes through the vibro screen 70 is collected in a water collection tank 90. The water 91 stored in the water collection tank 90 is supplied to the sand cyclone 110 through the pipe 100 by a pump (not shown), and the water 91 is supplied to one end of the crushing fire 120. In the crushing fire 110, the sand contained in the water 91 is separated by the rotation of the spiral screw, and is dropped onto the ground from the other end of the crushing fire 120. Reference numeral 121 indicates the sand thus dropped. If necessary, a water collection tank other than the water collection tank 90 is provided below the gravel recovery conveyor 80, and the water that has permeated the gravel recovery conveyor 80 is stored in this water collection tank, and this water is supplied to the fine sand cyclone provided above the crushing fire 120, and this water is supplied to one end of the crushing fire 120. In this case, in the crushing fire 120, the fine sand contained in the water is separated by the rotation of the spiral screw, and is dropped onto the ground from the other end of the crushing fire 120. In this case, the sand 121 also includes the fine sand. Water from the fine sand cyclone is fed to the sludge tank. The water stored in the sludge tank is sent to the immediate dewatering unit for dewatering, and the dewatered sludge water is passed through a filter press to form a dewatered cake on the ground. The filtered water discharged from the filter press is returned to the supernatant tank 30.

[0021] In this wash water treatment plant, coils C1 and C2 are wound in the middle of a pipe 40 for supplying the supernatant water 31 from the supernatant water tank 30 to the hopper 52 of the drum 51 of the mixer truck 50, and in the middle of a pipe 100 for supplying the water 91 stored in the water collection tank 90 to a sand cyclone 110, and are connected to an AC current supply device 20.

[0022] An embodiment will be described.

[0023] While actually operating an actual cleaning water treatment plant having the configuration shown in FIG. 4, the effectiveness of treating the cleaning water or the cleaning water after cleaning was confirmed at the time of installation of coils C1, C2 and alternating current supply device 20 (hereinafter simply referred to as "at installation") and about two months after installation.

[0024] FIG. 5 shows pipes corresponding to the pipes 40 and 100 of the actual machine, with the vertical pipe at the back corresponding to the pipe 40 and the horizontal pipe at the front corresponding to the pipe 100. Both pipes 40 and 100 are steel pipes with a diameter of 10 cm. In FIG. 5, most of the coils C1 and C2 are taped and only a portion of them is visible. FIG. 5 shows a portion of the AC current supply device 20. As the AC current supply device 20, a commercially available Dollman Shock model number MS-α1000 manufactured by Maxim Corporation was used. The number of turns of the coils C1 and C2 is 16 turns each, the number of turns per unit length is approximately 1.5 turns / cm, and the waveform of the AC current flowing through the coils C1 and C2 is as shown in FIG. 3A, and the frequency range of f1 to f2 is 4.5 kHz to 8 kHz. The frequency spectrum of this AC current is as shown in FIG. 3C. The maximum current value in the frequency range of f1 to f2 is approximately 2.2 A (2400 mA).

[0025] FIG. 6A shows the car wash chute 60 when it is installed, and FIG. 6B shows the car wash chute 60 about two months after it is installed. "DS" in FIG. 6A and FIG. 6B refers to the coils C1, C2 and the AC supply device 20 (hereinafter the same). As shown in FIG. 6A, when it is installed, the surface of the car wash chute 60 is covered with deposits derived from the fresh concrete. In contrast, as shown in FIG. 6B, about two months after it is installed, it can be seen that the deposits derived from the fresh concrete that were attached to the surface of the car wash chute 60 have peeled off over a wide area. This is the effect obtained as a result of treating the wash water by passing an AC current by the AC supply device 20 through the coils C1, C2 wound around the pipe 40 through which the supernatant water 31 flows.

[0026] Fig. 7A shows the vibroscreen 70 when it was installed, and Fig. 7B shows the vibroscreen 70 about two months after it was installed. As shown in Fig. 7A, when it was installed, the sieve surface of the vibroscreen 70 was widely covered with deposits derived from the fresh concrete. In contrast, as shown in Fig. 7B, about two months after it was installed, it can be seen that the deposits derived from the fresh concrete that had been attached to the sieve surface of the vibroscreen 70 had peeled off over a wide area. This is the effect obtained as a result of treating the wash water by passing an alternating current from the alternating current supply device 20 through the coils C1 and C2 wound around the pipe 40 through which the supernatant water 31 flows.

[0027] Fig. 8A shows the water collection tank 90 at the time of installation, and Fig. 8B shows the water collection tank 90 about two months after installation. As shown in Fig. 8A, at the time of installation, the surface of the steel frame of the water collection tank 90 is widely covered with deposits originating from the fresh concrete. In contrast, as shown in Fig. 8B, it can be seen that about two months after installation, the deposits originating from the fresh concrete that were attached to the surface of the steel frame of the water collection tank 90 have peeled off over a wide area. This is the effect obtained as a result of treating the wash water by passing an alternating current from the alternating current supply device 20 through the coils C1 and C2 wound around the pipe 40 through which the supernatant water 31 flows.

[0028] 9A shows the gravel recovery conveyor 80 at the time of installation, and FIG. 9B shows the gravel recovery conveyor 80 about two months after installation. As shown in FIG. 9A, the surface of the gravel recovery conveyor 80 is widely covered with deposits derived from the fresh concrete at the time of installation. In contrast, as shown in FIG. 9B, it can be seen that the deposits derived from the fresh concrete attached to the surface of the gravel recovery conveyor 80 about two months after installation have almost completely peeled off. This is the effect obtained as a result of treating the wash water by passing an alternating current from the alternating current supply device 20 through the coils C1 and C2 wound around the pipe 100 for supplying the water 91 stored in the water collection tank 90 to the sand cyclone 110.

[0029] FIG. 10A shows the inside of the crush fire 120 at the time of installation, and FIG. 10B shows the inside of the crush fire 120 about two months after installation. As shown in FIG. 10A, the walls and the spiral screw of the crush fire 120 are widely covered with deposits derived from the fresh concrete at the time of installation. In contrast, as shown in FIG. 10B, it can be seen that the deposits derived from the fresh concrete attached to the walls and the spiral screw of the crush fire 110 have peeled off over a wide area about two months after installation. This is the effect obtained as a result of treating the water 91 by applying an alternating current from the alternating current supply device 20 to the coils C1 and C2 wound around the pipe 100 for supplying the water 91 stored in the water collection tank 90 to the sand cyclone 110.

[0030] FIG. 11A shows the hopper nozzle of the sand cyclone 110 at the time of installation, and FIG. 11B shows the hopper nozzle of the sand cyclone 110 about two months after installation. As shown in FIG. 11A, the surface of the tip of the hopper nozzle of the sand cyclone 110 is covered with deposits derived from the fresh concrete at the time of installation. In contrast, as shown in FIG. 11B, it can be seen that about two months after installation, the deposits derived from the fresh concrete attached to the surface of the tip of the hopper nozzle of the sand cyclone 110 have peeled off over a wide area, exposing the base. This is the effect obtained as a result of treating the water 91 by applying an alternating current from the alternating current supply device 20 to the coils C1 and C2 wound around the piping 100 for supplying the water 91 stored in the water collection tank 90 to the sand cyclone 110.

[0031] Incidentally, the inside of drum 51 was washed by supplying washing water from hopper 52 attached to drum 51 of mixer truck 50, but since it is not easy to photograph the inside of drum 51, no photographs are included here. However, as a result of visually observing the inner wall of drum 51, it was confirmed that the solidified material originating from the ready-mixed concrete that had been attached before washing had peeled off over a wide area after washing.

[0032] Although the embodiment and examples of the present invention have been specifically described above, the present invention is not limited to the above-mentioned embodiment and examples, and various modifications based on the technical concept of the present invention are possible.

[0033] For example, the numerical values, configurations, shapes, materials, methods, etc. given in the above-mentioned embodiments and examples are merely examples, and numerical values, configurations, shapes, materials, methods, etc. different from these may be used as necessary. [Explanation of symbols]

[0034] 10...piping, 20...alternating current supply device, 21...power cable, 30...supernatant tank, 31...supernatant water, 40...piping, 50...mixer truck, 51...drum, 52...hopper, 53...scoop, 60...car wash chute, 70...vibro screen, 80...gravel recovery conveyor, 90...water collection tank, 100...piping, 110...sand cyclone, 120...crush fire, C...cable, C1, C2...coil

Claims

1. A pipe through which washing water used for washing the inside of a container in which ready-mixed concrete is stored or a pipe through which ready-mixed concrete is poured, or washing water used for said washing is poured; a coil wound around at least one portion of the outer circumferential surface of the tube; An alternating current supply device for supplying an alternating current having a frequency that continuously increases and decreases repeatedly in at least a part of a frequency range of 100 Hz to 10 kHz to the coil; having A cleaning water treatment system in which the AC current is applied to the coil by the AC current supply device while the cleaning water is applied to the pipe.

2. 2. The cleaning water treatment system according to claim 1, wherein the at least a portion of the frequency range is from 4.5 kHz to 8 kHz.

3. 2. The cleaning water treatment system according to claim 1, wherein the alternating current repeats increasing and decreasing in frequency within at least a portion of the frequency range a plurality of times per second.

4. 2. The wash water treatment system of claim 1, wherein said alternating current is a square wave.

5. 2. The wash water treatment system according to claim 1, wherein the container is a drum of a mixer truck or a mixer in a ready-mix concrete manufacturing plant.

6. 2. A wash water treatment system according to claim 1, wherein the pipe is a pipe for supplying supernatant water and / or a pipe for connecting a water collection tank and a sand cyclone in a wash water treatment plant attached to a ready-mix concrete manufacturing plant.

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