Coated waste liquid treatment apparatus

Abstract

To provide a coated waste liquid treatment apparatus, a coated waste liquid treatment system, and a coated waste liquid treatment method capable of reducing a time and cost of maintaining and managing waste tanks where coated waste liquid containing excess paint accumulates.SOLUTION: A coated waste liquid treatment apparatus 20 includes a waste liquid recovery pump 21 for suctioning the coated waste liquid collected in the waste liquid tank 12, an ozone treatment tank 22 for ozone treatment of the coated waste liquid supplied from the waste liquid recovery pump, an ozone generator 23 for generating ozone gas from oxygen gas and supplying the generated ozone gas to the ozone treatment tank, a deaeration tank 24 for collecting purified water in which ozone gas is degassed from the ozonated water supplied from the ozonation tank, and an ozone decomposer 25 for decomposing the ozone gas supplied from the ozonation tank, the return pump 29 which returns the purified water collected in the degas tank to the waste tank, and a controller 28 that controls the waste collection pump, the return pump, and the ozone generator.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a paint waste liquid treatment device, a paint waste liquid treatment system, and a paint waste liquid treatment method.

Background Art

[0002] Conventionally, in order to protect or decorate a metal workpiece, etc., a metal painted product has been manufactured by spraying paint onto the workpiece using a spray gun. For example, Patent Document 1 discloses a coating apparatus that forms a paint film (coating film) on a workpiece such as an automobile body by spraying paint dissolved in a solvent onto the workpiece using a spray gun in a paint booth.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as described in Patent Document 1, when forming a coating film on the surface of a workpiece using a spray gun, only about 1 to 2% of the entire sprayed paint adheres to the workpiece, and the surplus paint that does not adhere to the workpiece accumulates in a waste liquid tank together with the washing water that washes away the surplus paint. Since the paint waste liquid in the waste liquid tank contains organic substances derived from the surplus paint, bacteria multiply and decay after a long time, and a foul odor is emitted by mixing with the paint odor and the solvent odor, resulting in a significant deterioration of the working environment for the operator. In order to address this problem, it is necessary to have the paint waste liquid containing the surplus paint collected by a contractor as industrial waste, or to add chemicals such as preservatives and killer agents to the waste liquid tank to make it easier to recover the surplus paint, which causes a problem of requiring a great deal of labor and cost for the maintenance and management of the waste liquid tank.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a paint waste liquid treatment apparatus, a paint waste liquid treatment system, and a paint waste liquid treatment method that can reduce the labor and cost involved in maintaining and managing a waste liquid tank in which paint waste liquid containing excess paint accumulates.

Means for Solving the Problems

[0006] In order to solve the above problems, according to an aspect of the present invention, there is provided a paint waste liquid treatment apparatus including: a waste liquid recovery pump for sucking the paint waste liquid stored in a waste liquid tank; an ozone treatment tank for subjecting the paint waste liquid supplied from the waste liquid recovery pump to ozone treatment; an ozone generator for generating ozone gas from oxygen gas and supplying the generated ozone gas to the ozone treatment tank; a deaeration tank for storing purified water from which ozone gas has been deaerated from the ozone-treated water supplied from the ozone treatment tank; an ozone decomposer for decomposing the ozone gas supplied from the deaeration tank; a return pump for returning the purified water stored in the deaeration tank to the waste liquid tank; and a controller for controlling the waste liquid recovery pump, the return pump, and the ozone generator.

[0007] In order to solve the above problems, according to another aspect of the present invention, there is provided a paint waste liquid treatment system including: a paint booth having a waste liquid tank for storing paint waste liquid containing excess paint; a waste liquid recovery pump for sucking the paint waste liquid; an ozone treatment tank for subjecting the paint waste liquid supplied from the waste liquid recovery pump to ozone treatment; an ozone generator for generating ozone gas from oxygen gas and supplying the generated ozone gas to the ozone treatment tank; a deaeration tank for storing purified water from which ozone gas has been deaerated from the ozone-treated water supplied from the ozone treatment tank; an ozone decomposer for decomposing the ozone gas supplied from the deaeration tank; a return pump for returning the purified water stored in the deaeration tank to the waste liquid tank; and a controller for controlling the waste liquid recovery pump, the return pump, and the ozone generator.

[0008] To solve the above problems, according to another aspect of the present invention, a waste liquid recovery pump has a suction step of sucking the coating waste liquid stored in the waste liquid tank; an ozone treatment tank has an ozone treatment step of subjecting the coating waste liquid supplied from the waste liquid recovery pump to ozone treatment; an ozone generator generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank in an ozone gas supply step; a degassing tank has a degassing step of storing purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank; an ozone decomposer has a step of decomposing the ozone gas supplied from the degassing tank; and a return pump has a return step of returning the purified water stored in the degassing tank to the waste liquid tank. A coating waste liquid treatment method is provided in which a purification cycle passing through the suction step, the ozone treatment step, the ozone gas supply step, the degassing step, and the return step is executed.

[0009] In this specification, "coating waste liquid" means a cleaning liquid containing surplus paint and organic solvent, and "ozone-treated water" means a liquid containing purified water obtained by purifying (decomposing) the coating waste liquid with ozone gas and surplus ozone gas not used for purifying the coating waste liquid. Also, "purified water" means a liquid from which ozone gas has been degassed from the ozone-treated water. This liquid may contain, for example, trace amounts of inorganic substances derived from surplus paint.

Advantages of the Invention

[0010] As described above, the coating waste liquid treatment apparatus, the coating waste liquid treatment system, and the coating waste liquid treatment method of the present invention can reduce the costs and labor involved in maintaining and managing the waste liquid tank for storing the coating waste liquid.

Brief Description of the Drawings

[0011]

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. Note that the dimensions and scales of each part in the drawings are different from the actual ones. Also, the drawings may be schematically shown for easy understanding. Furthermore, the scope of the present invention is not limited to the embodiments exemplified below unless there is a description specifically limiting the present invention.

[0013] 1. Embodiment <<First Embodiment>> <Configuration of Coating Waste Liquid Treatment System> FIG. 1 is a schematic diagram showing a configuration example of a coating waste liquid treatment system 1 according to the present embodiment. The coating waste liquid treatment system 1 includes a coating booth 10 and a coating waste liquid treatment apparatus 20 (hereinafter referred to as the treatment apparatus 20).

[0014] [Coating Booth] The painting booth 10 has a spray gun 11, a waste liquid tank 12, and a circulation pump 13. The spray gun 11 sprays paint onto the workpiece W. Excess paint that is not attached to the workpiece W among the paint sprayed from the spray gun 11 is received by a scattered paint receiver U arranged behind the workpiece W and accumulates therein. The excess paint accumulated in the scattered paint receiver U is washed away by the cleaning liquid in the waste liquid tank 12 sucked by the circulation pump 13. For this reason, a cleaning liquid containing excess paint (hereinafter referred to as painting waste liquid) is stored in the waste liquid tank 12. The painting waste liquid contains pigments or organic solvents derived from the excess paint, etc.

[0015] The circulation pump 13 sucks the supernatant that contains relatively little excess paint due to the sedimentation of the excess paint in the painting waste liquid stored in the waste liquid tank 12. The supernatant is recycled by the circulation pump 13 as a cleaning liquid for washing away the excess paint accumulated in the scattered paint receiver U. The waste liquid tank 12 is, for example, several tens of cm deep and has a capacity of several hundred to several thousand liters.

[0016] [Painting Waste Liquid Treatment Device] The treatment device 20 is a waste liquid treatment device that repeats a cycle of subjecting the painting waste liquid stored in the waste liquid tank 12 of the painting booth 10 to ozone treatment by bringing it into contact with ozone gas in an ozone treatment tank 22 and returning the purified water generated by the ozone treatment to the waste liquid tank 12.

[0017] The treatment device 20 has a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a degassing tank 24, an ozone decomposer 25, a return pump 29, a return pipe 22R, and a controller 28. In addition to these, the treatment device 20 may also have an oxygen concentrator 26 and a compressor 27 as shown in FIG. 1.

[0018] The waste liquid recovery pump 21 is connected to a hose pipe L2 connected to the ozone treatment tank 22. The waste liquid recovery pump 21 is a submersible pump that sucks the painting waste liquid stored in the waste liquid tank 12 of the painting booth 10 and supplies it to the ozone treatment tank 22 via the hose pipe L2.

[0019] The ozone treatment tank 22 is a cylindrical tank that makes the coating waste liquid supplied from the waste liquid recovery pump 21 contact and react with ozone gas of a specified concentration generated by the ozone generator 23 to obtain ozone-treated water, and supplies the generated ozone-treated water to the degassing tank 24. The ozone-treated water generated in the ozone treatment tank 22 contains purified water in which the coating waste liquid has been purified (decomposed) by the ozone gas and surplus ozone gas that has not been used for the purification of the coating waste liquid.

[0020] The ozone generator 23 is connected to the oxygen concentrator 26 and the diffuser pipe 23a. The ozone generator 23 generates high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26 and supplies the generated ozone gas to the diffuser pipe 23a. The controller 28 can appropriately control the supply amount of the ozone gas supplied to the diffuser pipe 23a by controlling the ozone generator 23.

[0021] The oxygen concentrator 26 concentrates the air supplied from the compressor 27 to generate high-concentration oxygen gas. The diffuser pipe 23a diffuses the ozone gas supplied from the ozone generator 23 in the ozone treatment tank 22. Note that the ozone generator 23 is not limited to the mode of generating high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26. For example, the ozone generator 23 may be a device that generates ozone gas using the discharge method or the ultraviolet lamp method.

[0022] The degassing tank 24 is connected to the ozone treatment tank 22 and the ozone decomposer 25. The degassing tank 24 is a tank that stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank 22. The degassing tank 24 functions as a buffer tank that temporarily stores the purified water to be returned to the waste liquid tank 12.

[0023] As shown in Fig. 1, the degassing tank 24 is equipped with liquid level detection sensors S1 and S2. The liquid level detection sensor S1 detects the liquid level of the purified water stored in the degassing tank 24 and outputs a signal to the controller 28 to activate the return pump 29. The liquid level detection sensor S2 detects the liquid level of the purified water stored in the degassing tank 24 and outputs a stop signal to the controller 28 to stop the return pump 29.

[0024] The ozone decomposer 25 is a cylindrical tank that decomposes the ozone gas supplied from the degassing tank 24 and discharges it into the atmosphere as oxygen. Specifically, the ozone decomposer 25 decomposes the ozone gas separated from the ozone-treated water in the degassing tank 24 and the unreacted excess ozone gas diffused from the diffuser pipe 23a and not used for purifying the coating waste liquid in the ozone treatment tank 22 into oxygen and discharges it into the atmosphere.

[0025] The ozone decomposer 25 contains a catalyst 25C that decomposes the ozone gas supplied from the degassing tank 24. The catalyst 25C is not particularly limited as long as it can decompose ozone gas into oxygen. For example, manganese dioxide or the like is adopted.

[0026] The return pump 29 is a submersible pump connected to the hose pipe L1. The return pump 29 is activated under the control of the controller 28 that receives the detection signal from the liquid level detection sensor S1, sucks the purified water in the degassing tank 24, and returns the sucked purified water to the waste liquid tank 12. Thereby, the water level of the purified water in the degassing tank 24 is maintained below a predetermined level, preventing the purified water from overflowing from the degassing tank 24 or flowing back into the ozone decomposer 25. Also, the return pump 29 stops under the control of the controller 28 that receives the stop signal from the liquid level detection sensor S2.

[0027] The return pipe 22R is connected to the ozone treatment tank 22 and the degassing tank 24. In this embodiment, when the coating waste liquid is supplied from the waste liquid recovery pump 21 into the ozone treatment tank 22, the pressure inside the ozone treatment tank 22 increases, making it difficult for the coating waste liquid to enter the ozone treatment tank 22. However, by allowing the return pipe 22R to release the pressure, the supply of the coating waste liquid from the waste liquid recovery pump 21 into the ozone treatment tank 22 becomes possible.

[0028] As shown in FIG. 1, one end of the return pipe 22R extends into the ozone treatment tank 22. Therefore, when the water surface of the ozone-treated water reaches one end of the return pipe 22R, the ozone-treated water in the ozone treatment tank 22 overflows into the degassing tank 24 through the return pipe 22R. As a result, it is possible to prevent the water level of the ozone-treated water in the ozone treatment tank 22 from exceeding a predetermined level, and to prevent the ozone-treated water from leaking from the ozone treatment tank 22.

[0029] The controller 28 is electrically connected to the waste liquid recovery pump 21, the return pump 29, the ozone generator 23, the compressor 27, and the liquid level detection sensors S1 and S2. The controller 28 is not particularly limited, but is, for example, an information processing device such as a sequencer or a computer.

[0030] The controller 28 controls the start / stop of the waste liquid recovery pump 21, the return pump 29, and the compressor 27, and the ozone generation amount of the ozone generator 23. The controller 28 has an input / output interface that outputs control signals to the waste liquid recovery pump 21, the return pump 29, the compressor 27, etc., and receives detection signals from the liquid level detection sensors S1 and S2 and inputs from the operator of the coating waste liquid treatment device, etc.

[0031] As described above, the processing device 20 according to the present embodiment includes a waste liquid recovery pump 21 that sucks the coating waste liquid stored in the waste liquid tank 12, an ozone treatment tank 22 that performs ozone treatment on the coating waste liquid supplied from the waste liquid recovery pump 21, an ozone generator 23 that generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank 22, a degassing tank 24 that stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank 22, an ozone decomposer 25 that decomposes the ozone gas supplied from the degassing tank 24, a return pump 29 that returns the purified water stored in the degassing tank 24 to the waste liquid tank 12, and a controller that controls the waste liquid recovery pump 21, the return pump 29, and the ozone generator 23.

[0032] According to the above aspect, the processing device 20 performs ozone treatment on the coating waste liquid supplied from the waste liquid tank 12, and by repeating the cycle of returning the purified water generated by the ozone treatment to the waste liquid tank 12, the cleaning liquid accumulated in the waste liquid tank 12 can be made into purified water from which excess paint has been purified. As a result, there is no need to have a contractor collect the coating waste liquid containing excess paint as industrial waste as in the prior art, or to add chemicals such as preservatives and killer agents to the waste liquid tank 12 to make it easier to recover the excess paint, and the labor and cost required for the maintenance and management of the waste liquid tank 12 can be significantly reduced compared to the past.

[0033] <Operation of Coating Waste Liquid Treatment Device> FIG. 2 is a flowchart showing an example of the operation of the processing device 20. Hereinafter, an example of the operation of the processing device 20 will be described with appropriate reference to FIG. 2.

[0034] (Step St1: Start Waste Liquid Recovery Pump) Upon receiving an instruction from the operator of the processing device 20 to start the waste liquid recovery pump 21, the controller 28 starts the waste liquid recovery pump 21.

[0035] (Step St2: Suction Step) The waste liquid recovery pump 21 sucks the coating waste liquid stored in the waste liquid tank 12 and supplies the sucked coating waste liquid to the ozone treatment tank 22.

[0036] (Step St3: Ozone gas supply process) The ozone generator 23 generates high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26, and supplies the generated high-concentration ozone gas to the ozone treatment tank 22.

[0037] (Step St4: Ozone treatment process) The coating waste liquid supplied from the waste liquid tank 12 is ozone-treated in the ozone treatment tank 22 by the high-concentration ozone gas supplied from the ozone generator 23, and becomes ozone-treated water containing purified water and unreacted ozone gas. In this ozone treatment, the surplus paint in the coating waste liquid is decomposed by the ozone gas into water and gases (such as oxygen and carbon dioxide). The ozone-treated water is supplied to the degassing tank 24.

[0038] (Step St5: Degassing process) In the degassing tank 24, ozone gas is degassed from the ozone-treated water supplied from the ozone treatment tank 22. The ozone gas separated from the ozone-treated water flows into the ozone decomposer 25, is decomposed into oxygen, and is released to the atmosphere.

[0039] (Step St6: Has a detection signal been obtained from the liquid level detection sensor S1?) The controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S1. When the processing device 20 is determined by the controller 28 not to have obtained a detection signal from the liquid level detection sensor S1 (NO in Step St6), the previous Steps St2 to 5 are executed again until the controller 28 obtains a detection signal from the liquid level detection sensor S1 (until the purified water in the degassing tank 24 reaches a predetermined water level).

[0040] (Step St7: Start the return pump) When the controller 28 determines that a detection signal has been obtained from the liquid level detection sensor S1 (YES in Step St6), the controller 28 starts the return pump 29. The return pump 29 sucks the purified water stored in the degassing tank 24 and returns the sucked purified water to the waste liquid tank 12.

[0041] (Step St8: Has a detection signal been obtained from the liquid level detection sensor S2?) The controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S2.

[0042] (Step St9: Stop the return pump) When the controller 28 determines that a detection signal has been obtained from the liquid level detection sensor S2 (YES in Step St8), the controller 28 stops the return pump 29.

[0043] (Step St10: Has a stop instruction been input?) The controller 28 determines whether or not an instruction to stop the operation of the processing device 20 has been input from the operator of the processing device 20. When the controller 28 determines that no instruction to stop the processing device 20 has been input from the operator (NO in Step St10), the processing device 20 re-executes the previous Steps St2 to 9. The processing device 20 repeats the purification cycle of the previous Steps St2 to 9 until an instruction to stop the operation of the processing device 20 is input from the operator of the processing device 20. As a result, the coating waste liquid is purified, and the cleaning liquid accumulated in the waste liquid tank 12 becomes purified water from which the excess paint has been purified. Therefore, there is no need to have the coating waste liquid containing excess paint collected by a contractor as industrial waste as in the conventional case, or to add chemicals such as preservatives and killer agents to the waste liquid tank 12 to facilitate the collection of excess paint, and the labor and cost required for the maintenance and management of the waste liquid tank 12 can be significantly reduced compared to the past.

[0044] (Step S11: Stop the operation) On the other hand, when the controller 28 determines that an instruction to stop the operation of the processing device 20 has been input from the operator of the processing device 20 (YES in Step St10), the controller 28 outputs a stop signal to the waste liquid recovery pump 21, the ozone generator 23, and the compressor 27. These devices that have obtained the stop signal from the controller 28 stop operating. As a result, the operation of the processing device 20 stops.

[0045] <<Second Embodiment>> Next, a second embodiment of the present invention will be described. In the following description of the second embodiment, the same components and steps as those in the first embodiment may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0046] <Configuration of the Painting Waste Liquid Treatment System> FIG. 3 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 2 according to the second embodiment. The painting waste liquid treatment system 2 includes a painting booth 10 and a painting waste liquid treatment device 30 (hereinafter referred to as the treatment device 30).

[0047] [Painting Waste Liquid Treatment Device] The treatment device 30 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a degassing tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, and a compressed air supply device 227.

[0048] FIG. 4 is a schematic diagram showing a configuration example of the compressed air supply device 227. The compressed air supply device 227 includes a painting compressor 227a, a built-in compressor 227b, a three-way valve 227c, a solenoid valve 227d, an air pressure detection sensor 227e, and flow paths R1 to R3. The three-way valve 227c is an example of a "switching mechanism". The painting compressor 227a is an example of a "first compressor", and the built-in compressor 227b is an example of a "second compressor". Further, the flow paths R2 and R3 are examples of a "first flow path", and the flow paths R1 and R3 are examples of a "second flow path".

[0049] The painting compressor 227a is connected to the flow path R2 and supplies factory air to the oxygen concentrator 26 via the flow paths R2 and R3. The painting compressor 227a is provided near the painting booth 10 or at a location far from the painting booth 10 within the factory that houses the painting waste liquid treatment system 2. The painting compressor 227a starts / stops under the control of the controller 28 that has received a detection signal from the air pressure detection sensor 227e.

[0050] The built-in compressor 227b is a compressor that is connected to the flow path R1 and supplies air to the oxygen concentrator 26 via the flow paths R1 and R3, and is built into the processing device 30. The built-in compressor 227b may be built into the processing device 30 or may be provided at any location within the factory that houses the paint waste liquid treatment system 2. The built-in compressor 227b starts / stops under the control of the controller 28 that has received the detection signal from the air pressure detection sensor 227e.

[0051] The three-way valve 227c is connected to the flow paths R1 to R3, and switches the communication / shut-off of the flow paths R1 to R3 based on the control of the controller 28 that has acquired the detection signal from the air pressure detection sensor 227e. The three-way valve 227c is typically an electromagnetic three-way valve, but is not limited thereto and may be a manual three-way valve.

[0052] The solenoid valve 227d is provided in the flow path R2, and switches the communication / shut-off of the flow path R2 based on the control of the controller 28 that has acquired the detection signal from the air pressure detection sensor 227e. The air pressure detection sensor 227e detects the air pressure (internal pressure of the flow path R2) in the flow path R2 of the air discharged from the painting compressor 227a and outputs a detection signal to the controller 28. Note that the solenoid valve 227d may be omitted as necessary.

[0053] The controller 28 according to the second embodiment mutually switches the first communication state and the second communication state of the compressed air supply device 227 based on the detection signal from the air pressure detection sensor 227e.

[0054] In the first communication state, each element constituting the compressed air supply device 227 is in the following states (a) to (e). As a result, the air discharged from the painting compressor 227a is supplied to the oxygen concentrator 26 via the flow paths R2 and R3.

[0055] (a) The painting compressor 227a is in an operating state. (b) The built-in compressor 227b is in a stopped state. (c) The solenoid valve 227d is in an open valve state. (d) The flow paths R1 and R3 are in a blocked state by the three-way valve 227c. (e) The flow paths R2 and R3 are in a communicating state by the three-way valve 227c.

[0056] In the second communicating state, each element constituting the compressed air supply device 227 is in the following states (f) to (j). As a result, the air discharged from the built-in compressor 227b is supplied to the oxygen concentrator 26 via the flow paths R1 and R3.

[0057] (f) The painting compressor 227a is in a stopped state. (g) The built-in compressor 227b is in an operating state. (h) The solenoid valve 227d is in a closed valve state. (i) The flow paths R1 and R3 are in a communicating state by the three-way valve 227c. (j) The flow paths R2 and R3 are in a blocked state by the three-way valve 227c.

[0058] (Specific operation example of the processing device) Next, a specific operation example of the processing device 30 will be described. The operator of the processing device 30 operates the controller 28 at the end of business on Friday to shift the compressed air supply device 227 from the first communicating state (the state of the compressed air supply device 227 from Monday to Friday) to the second communicating state. The processing device 30 repeats the above purification cycle throughout the day from Saturday to Sunday when painting work is not performed in the painting booth 10. As a result, the worker in the painting booth 10 can start the painting work from the state where the painting waste liquid stored in the waste liquid tank 12 has become purified water on Monday after the holiday, and the working environment of the worker is improved.

[0059] <Operation of the painting waste liquid treatment device> FIG. 5 is a flowchart showing an example of the operation of the processing device 30. Hereinafter, an example of the operation of the processing device 30 will be described with appropriate reference to FIG. 5.

[0060] (Step St21: Start the waste liquid recovery pump and the painting compressor) Upon receiving an instruction from the operator of the processing device 30 to start the waste liquid recovery pump 21 and the painting compressor 227a, the controller 28 starts the waste liquid recovery pump 21 and the painting compressor 227a. At the stage where step St21 is executed, the compressed air supply device 227 is in the first communication state.

[0061] (Step St22: Is the internal pressure less than a predetermined threshold value?) The controller 28 determines whether the internal pressure of the flow path R2 measured by the air pressure detection sensor 227e is less than a predetermined threshold value. When the controller 28 determines that the measured internal pressure is less than the predetermined threshold value (YES in step St22), it executes the previous step St3.

[0062] (Step St23: Shift to the second communication state) On the other hand, when the controller 28 determines that the internal pressure of the flow path R2 measured by the air pressure detection sensor 227e is equal to or greater than the predetermined threshold value (NO in step St22), it shifts the compressed air supply device 227 from the first communication state to the second communication state. As a result, even if some abnormality occurs in the painting compressor 227a and the painting compressor 227a is stopped, the built-in compressor 227b functions as a backup for the painting compressor 227a, so the supply of ozone gas to the ozone treatment tank 22 can be continued without stopping.

[0063] <<Third Embodiment>> Next, a third embodiment of the present invention will be described. In the following description of the third embodiment, the same components and steps as those in the first and second embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0064] <Configuration of the Painting Waste Liquid Treatment System> FIG. 6 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 3 according to the third embodiment. The painting waste liquid treatment system 3 includes a painting booth 10 and a painting waste liquid treatment device 40 (hereinafter referred to as the treatment device 40).

[0065] [Painting Waste Liquid Treatment Device] The treatment device 40 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a degassing tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, and a backflow detection sensor 41.

[0066] The backflow detection sensor 41 is connected to the ozone treatment tank 22 and the ozone generator 23. Also, the backflow detection sensor 41 is electrically connected to the controller 28. The backflow detection sensor 41 has a housing for storing the ozone-treated water flowing back from the ozone treatment tank 22 and a float switch provided in the housing. When the ozone-treated water in the housing reaches a predetermined water level or higher, the float switch outputs a detection signal to the controller 28.

[0067] [Operation of Painting Waste Liquid Treatment Device] FIG. 7 is a flowchart showing an example of the operation of the treatment device 40. Hereinafter, an example of the operation of the treatment device 40 will be described with appropriate reference to FIG. 7.

[0068] (Step St31: Have a detection signal been obtained from the backflow detection sensor?) The controller 28 determines whether a detection signal has been obtained from the backflow detection sensor 41. When it is determined by the controller 28 that the treatment device 40 has not obtained a detection signal from the backflow detection sensor 41 (NO in step St31), the previous step St5 is executed.

[0069] On the other hand, when the controller 28 determines that a detection signal has been obtained from the backflow detection sensor 31 (YES in step St31), the operation of the treatment device 40 is stopped. Specifically, the controller 28 outputs a stop signal to the waste liquid recovery pump 21, the ozone generator 23, and the compressed air supply device 227 (painting compressor 227a or built-in compressor 227b). These devices that have obtained the stop signal from the controller 28 stop operating.

[0070] The processing device 40 according to the third embodiment can detect the backflow as described above by the backflow detection sensor 41 even when, for example, the outlet of the ozone treatment tank 22 is clogged by sludge of surplus paint flowing in from the waste liquid tank 12 and the ozone-treated water flows back to the ozone generator 23 side, and stops the operation when the backflow is detected. Thereby, it is possible to prevent the ozone generator 23 from being damaged by the ozone-treated water flowing back from the ozone treatment tank 22 and flowing into the ozone generator 23.

[0071] <<Fourth Embodiment>> Next, a fourth embodiment of the present invention will be described. In the following description of the fourth embodiment, the same components and steps as those in the first to third embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0072] <Configuration of Painting Waste Liquid Treatment System> FIG. 8 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 4 according to the fourth embodiment. The painting waste liquid treatment system 4 includes a painting booth 10 and a painting waste liquid treatment device 50 (hereinafter referred to as the treatment device 50).

[0073] [Painting Waste Liquid Treatment Device] The treatment device 50 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a deaeration tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 31, and a re-supply pump 51.

[0074] The re-supply pump 51 is connected to a hose pipe L3 connected to the ozone treatment tank 22. The re-supply pump 51 is also electrically connected to the controller 28. The re-supply pump 51 is a submersible pump that sucks the purified water stored in the deaeration tank 24 and re-supplies it to the ozone treatment tank 22 via the hose pipe L3.

[0075] <Operation of Painting Waste Liquid Treatment Device> Figures 9 and 10 are flowcharts showing an example of the operation of the processing device 50. Hereinafter, an example of the operation of the processing device 50 will be described with appropriate reference to FIGS. 9 and 10.

[0076] (Step St41: Start return pump) When the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S1 (YES in step St6), the controller 28 starts the return pump 29. The return pump 29 sucks the purified water stored in the deaeration tank 24 and returns the sucked purified water to the waste liquid tank 12.

[0077] (Step St42: Start replenishment pump) When the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S1 (YES in step St6), the controller 28 starts the replenishment pump 51. The replenishment pump 51 sucks the purified water stored in the deaeration tank 24 and replenishes the sucked purified water to the ozone treatment tank 22. Note that the controller 28 may execute step St42 simultaneously (at the same time) with the previous step St41, or may execute step St42 slightly later than step St41.

[0078] (Step St43: Has a detection signal been acquired from the liquid level detection sensor S2?) The controller 28 determines whether or not it has acquired a detection signal from the liquid level detection sensor S2.

[0079] (Step St44: Stop return pump) When the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S2 (YES in step St43), the controller 28 stops the return pump 29.

[0080] (Step St45: Has a stop instruction been input?) The controller 28 determines whether or not an instruction to stop the operation of the processing device 50 has been input from the operator of the processing device 50.

[0081] (Step St46: Stop operation) When the controller 28 determines that an instruction to stop the operation of the processing device 50 has been input from the operator of the processing device 50 (YES in step St45), the controller 28 outputs a stop signal to the waste liquid recovery pump 21, the re-supply pump 51, the ozone generator 23, and the compressed air supply device 227 (the painting compressor 227a or the built-in compressor 227b). These devices that have received the stop signal from the controller 28 stop operating. Thereby, the operation of the processing device 50 stops.

[0082] (Step St47: Ozone gas supply process) When the controller 28 does not determine that an instruction to stop the operation of the processing device 50 has been input from the operator of the processing device 50 (NO in step St45), the ozone generator 23 generates high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26 and supplies the generated high-concentration ozone gas to the ozone treatment tank 22.

[0083] (Step St48: Ozone treatment process) The purified water re-supplied from the deaeration tank 24 is ozone-treated again in the ozone treatment tank 22 by the high-concentration ozone gas supplied from the ozone generator 23, and becomes ozone-treated water containing the purified water and the unreacted ozone gas.

[0084] (Step St49: Deaeration process) In the deaeration tank 24, ozone gas is deaerated from the ozone-treated water re-supplied from the ozone treatment tank 22.

[0085] (Step St50: Re-supply process) The re-supply pump 51 sucks the purified water stored in the deaeration tank 24 and re-supplies the sucked purified water to the ozone treatment tank 22.

[0086] As can be understood from the flowcharts shown in FIGS. 9 and 10, after the return pump 29 is stopped, the processing device 50 repeats the purification cycle of the previous steps St47 to St50 (the purification cycle that circulates the ozone treatment tank 22 and the deaeration tank 24) until an instruction to stop the operation of the processing device 50 is input from the operator. As a result, the processing device 50 can proceed with the purification of the painting waste liquid without passing through the painting booth 10. Therefore, the operator in the painting booth 10 can perform other operations different from the painting operation (for example, cleaning in the waste liquid tank 12) in parallel while the purification cycle is being advanced in the processing device 50, improving the labor productivity and work efficiency of the operator.

[0087] <<Fifth Embodiment>> Next, a fifth embodiment of the present invention will be described. In the following description of the fifth embodiment, the same components and steps as those in the first to fourth embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0088] [Configuration of Painting Waste Liquid Treatment System] FIG. 11 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 5 according to the fifth embodiment. The painting waste liquid treatment system 5 includes a painting booth 10 and a painting waste liquid treatment device 60 (hereinafter referred to as the treatment device 60).

[0089] [Painting Waste Liquid Treatment Device] The treatment device 60 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a deaeration tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a re-supply pump 51, and a deterioration index unit 61.

[0090] The deterioration index unit 61 is provided at the outlet of the ozone decomposer 25 and includes a case and an ozone decomposing agent housed in the case. The case of the deterioration index unit 61 is, for example, a transparent case so that the operator of the processing device 60 can visually recognize the state of the ozone decomposing agent, and the gas from the ozone decomposer 25 flows in.

[0091] The ozone decomposer in the deterioration indicator unit 61 is, for example, a large number of granular bodies. The ozone decomposer does not change color due to the oxygen gas from the ozone decomposer 25, but changes color as it decomposes the ozone gas that was not decomposed by the catalyst 25C due to the deactivation of the catalyst 25C. The ozone decomposer is not particularly limited, but is, for example, a decomposer obtained by blending and molding special powdered activated carbon mainly composed of an adsorbent, alumina-silica gel (allophane).

[0092] The operator of the processing device 60 can grasp that the catalyst 25C is deactivated by checking the discoloration of the ozone decomposer in the deterioration indicator unit 61, and can know that it is necessary to replace the catalyst 25C with a new catalyst.

[0093] <<Sixth Embodiment>> Next, a sixth embodiment of the present invention will be described. In the following description of the sixth embodiment, the same components and steps as in the first to fifth embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0094] <Configuration of the Painting Waste Liquid Treatment System> FIG. 12 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 6 according to the sixth embodiment. The painting waste liquid treatment system 6 includes a painting booth 10 and a painting waste liquid treatment device 70 (hereinafter referred to as the treatment device 70).

[0095] [Painting Waste Liquid Treatment Device] The treatment device 70 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a degassing tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a re-supply pump 51, a deterioration indicator unit 61, and an ozone concentration measuring device 71.

[0096] The ozone concentration measuring device 71 is arranged inside or outside the processing device 70 and is electrically connected to the controller 28. The ozone concentration measuring device 71 measures the ozone concentration of the gas discharged from the ozone decomposer 25 and outputs information on the measurement result to the controller 28.

[0097] The ozone concentration measuring device 71 is not particularly limited. For example, it may be an ultraviolet absorption type ozone concentration meter that continuously measures the ozone concentration, an ozone concentration measuring instrument using a semiconductor sensor, or an ozone concentration measuring device using the constant potential electrolysis method.

[0098] <Operation of the coating waste liquid treatment device> FIG. 13 is a flowchart showing an example of the operation of the processing device 70. Hereinafter, an example of the operation of the processing device 70 will be described with appropriate reference to FIG. 13.

[0099] (Step St61: Is the ozone concentration less than a predetermined threshold value?) The controller 28 determines whether the ozone concentration measured by the ozone concentration measuring device 71 is less than a predetermined threshold value. When the controller 28 determines that the measured ozone concentration is less than the predetermined threshold value (YES in step St61), it executes the previous step St10.

[0100] (Step St62: Stop operation) When the controller 28 determines that the ozone concentration measured by the ozone concentration measuring device 71 is equal to or greater than a predetermined threshold value (NO in step St61), or when it determines that an instruction to stop the operation of the processing device 70 has been input from the operator of the processing device 70 (YES in step St10), the controller 28 outputs a stop signal to the waste liquid recovery pump 21, the ozone generator 23, and the compressed air supply device 227 (the coating compressor 227a or the built-in compressor 227b). These devices that have received the stop signal from the controller 28 stop operating. That is, the operation of the processing device 70 stops. Thereby, it is possible to prevent ozone gas with a concentration of a predetermined value or more from continuing to be discharged from the ozone decomposer 25, not only reducing the environmental load but also ensuring the safety of the operator of the processing device 70.

[0101] <<Seventh Embodiment>> Next, the seventh embodiment of the present invention will be described. In the following description of the seventh embodiment, the same components and steps as those in the first to sixth embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0102] <Configuration of Painting Waste Liquid Treatment System> FIG. 14 is a schematic diagram showing a configuration example of a painting waste liquid treatment system 7 according to the seventh embodiment. The painting waste liquid treatment system 7 includes a painting booth 10 and a painting waste liquid treatment device 80 (hereinafter referred to as the treatment device 80).

[0103] [Painting Waste Liquid Treatment Device] The treatment device 80 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a degassing tank 24, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a re-supply pump 51, a deterioration index unit 61, an ozone concentration measurement device 71, and a bubble sensor 81.

[0104] The bubble sensor 81 is provided in the degassing tank 24 and is electrically connected to the controller 28. The bubble sensor 81 detects bubbles of ozone gas contained in the ozone-treated water flowing in from the ozone treatment tank 22 and outputs a detection signal to the controller 28.

[0105] [Operation of Painting Waste Liquid Treatment Device] FIG. 15 is a flowchart showing an example of the operation of the treatment device 80. Hereinafter, an example of the operation of the treatment device 80 will be described with appropriate reference to FIG. 15.

[0106] (Step St71: Has a detection signal been obtained from the bubble sensor?) The controller 28 determines whether a detection signal has been obtained from the bubble sensor 81. When the controller 28 determines that a detection signal has not been obtained from the bubble sensor 81 (NO in step St71), it executes the previous step St7.

[0107] On the other hand, when the controller 28 determines that it has acquired a detection signal from the bubble sensor 81 (YES in step St71), it executes the previous step St11 to stop the operation of the processing device 80. As a result, even when the inflow of the ozone-treated water from the ozone treatment tank 22 to the degassing tank 24 is fast and the ozone-treated water rapidly accumulates in the degassing tank 24, the water level of the ozone-treated water in the degassing tank 24 is maintained below a predetermined level, preventing the ozone-treated water from overflowing from the degassing tank 24 or flowing back into the ozone decomposer 25.

[0108] <<Eighth Embodiment>> Next, the eighth embodiment of the present invention will be described. In the following description of the eighth embodiment, the same components and steps as those in the first to seventh embodiments are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0109] In the description of the eighth embodiment, an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other are defined. The X-axis, Y-axis, and Z-axis are three mutually orthogonal directions. As illustrated in FIG. 16, a direction along the X-axis as viewed from an arbitrary point is denoted as the X1 direction, and a direction opposite to the X1 direction is denoted as the X2 direction. The X-axis direction includes both the X1 direction and the X2 direction. Similarly, directions opposite to each other along the Y-axis as viewed from an arbitrary point are denoted as the Y1 direction and the Y2 direction. The Y-axis direction includes both the Y1 direction and the Y2 direction. Also, directions opposite to each other along the Z-axis as viewed from an arbitrary point are denoted as the Z1 direction and the Z2 direction. The Z-axis direction includes both the Z1 direction and the Z2 direction. Furthermore, the X-Y plane including the X-axis and the Y-axis corresponds to a horizontal plane. The Z-axis is an axis along the vertical direction.

[0110] FIG. 16 is a schematic diagram showing a configuration example of a coating waste liquid treatment system 8 according to the eighth embodiment. The coating waste liquid treatment system 8 includes a coating booth 10 and a coating waste liquid treatment device 90 (hereinafter referred to as the treatment device 90).

[0111] [Coating Waste Liquid Treatment Device] The processing device 90 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a deaeration tank 91, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a re-supply pump 51, a deterioration index unit 61, an ozone concentration measurement device 71, and a bubble sensor 81.

[0112] FIG. 17 is a schematic diagram showing a configuration example of the deaeration tank 91. The deaeration tank 91 is configured in the same manner as the deaeration tank 24 of the first embodiment and has the same functions, except for having a housing 91a, an inspection window 91b, and a seal member 91c.

[0113] The housing 91a stores purified water from which ozone gas has been deaerated from the ozone-treated water supplied from the ozone treatment tank 22. The inspection window 91b is, for example, a plate-like body made of glass that allows an operator of the processing device 90 to visually recognize the inside of the housing 91a from the outside, and is attached to the housing 91a. The inspection window 91b is configured not to come off from the housing 91a unless a lock mechanism (not shown) is released when it is attached to the housing 91a.

[0114] FIG. 18 is a rear view of the inspection window 91b viewed in the Y2 direction, FIG. 19 is a partial cross-sectional view taken along line A-A of FIG. 17. Further, FIG. 20 is an enlarged view showing a configuration example of the seal member 91c. The seal member 91c is provided at the periphery around the Y-axis of the surface of the inspection window 91b facing the Y1 direction as shown in FIG. 18, and is a packing interposed between the inspection window 91b and the housing 91a as shown in FIG. 19.

[0115] The seal member 91c has a two-layer structure as shown in FIG. 20. The seal member 91c includes a first elastic layer 911c and a second elastic layer 912c. The first elastic layer 911c adheres to the inspection window 91b. Also, in a state where the inspection window 91b is attached to the housing 91a, the second elastic layer 912c abuts against the housing 91a.

[0116] The first elastic layer 911c is, for example, a rubber member made of ethylene propylene diene rubber (EPDM). The second elastic layer 912c is, for example, a sponge member made of ethylene propylene diene rubber. However, the materials constituting the first and second elastic layers 911c and 912c are not limited to ethylene propylene diene rubber, and other materials may be adopted.

[0117] The seal member 91c seals the internal space defined by the inner surface of the housing 91a and the inner surface of the inspection window 91b facing the Y1 direction in a state where the inspection window 91b is attached to the housing 91a. Thereby, it is possible to prevent the purified water, ozone-treated water stored in the housing 91a, and ozone gas deaerated from the ozone-treated water in the deaeration tank 91 from leaking to the outside.

[0118] [[Ninth Embodiment]] Next, a ninth embodiment of the present invention will be described. In the following description of the ninth embodiment, the same components as those in the first to eighth embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0119] FIG. 21 is a schematic diagram showing a configuration example of a coating waste liquid treatment system 9 according to the ninth embodiment. The coating waste liquid treatment system 9 includes coating booths 10A and 10B and a coating waste liquid treatment apparatus 100 (hereinafter referred to as the treatment apparatus 100). Since the coating booths 10A and 10B have the same configuration as the coating booth 10, the description thereof will be omitted.

[0120] [Coating Waste Liquid Treatment Apparatus] The treatment apparatus 100 includes waste liquid recovery pumps 21A and 21B, an ozone treatment tank 22, an ozone generator 23, a deaeration tank 91, an ozone decomposer 25, return pumps 29A and 29B, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a resupply pump 51, a deterioration index unit 61, an ozone concentration measurement device 71, and a bubble sensor 81.

[0121] The waste liquid recovery pump 21A (first recovery pump) is connected to a hose pipe L4 connected to the ozone treatment tank 22. The waste liquid recovery pump 21A is a submersible pump that sucks the coating waste liquid stored in the waste liquid tank 12A (first waste liquid tank) of the painting booth 10A and supplies it to the ozone treatment tank 22 via the hose pipe L4.

[0122] The waste liquid recovery pump 21B (second recovery pump) is connected to a hose pipe L5 connected to the ozone treatment tank 22. The waste liquid recovery pump 21B is a submersible pump that sucks the coating waste liquid stored in the waste liquid tank 12B (second waste liquid tank) of the painting booth 10B and supplies it to the ozone treatment tank 22 via the hose pipe L5.

[0123] The return pump 29A (first return pump) operates under the control of the controller 28 that has received the detection signal from the liquid level detection sensor S1, sucks the purified water in the degassing tank 91, and returns the sucked purified water to the waste liquid tank 12A. Further, the return pump 29A stops under the control of the controller 28 that has received the detection signal from the liquid level detection sensor S2.

[0124] The return pump 29B (second return pump) operates under the control of the controller 28 that has received the detection signal from the liquid level detection sensor S1, sucks the purified water in the degassing tank 91, and returns the sucked purified water to the waste liquid tank 12B. Further, the return pump 29B stops under the control of the controller 28 that has received the detection signal from the liquid level detection sensor S2.

[0125] <Operation of the Coating Waste Liquid Treatment Device> Figs. 22 and 23 are flowcharts showing an example of the operation of the treatment device 100. Hereinafter, an example of the operation of the treatment device 100 will be described with appropriate reference to Figs. 22 and 23.

[0126] (Step St91: Start the waste liquid recovery pump 21A) The controller 28 starts the waste liquid recovery pump 21A.

[0127] (Step St92: Suction process) Next, the waste liquid recovery pump 21A sucks the coating waste liquid stored in the waste liquid tank 12A of the coating booth 10A, and supplies the sucked coating waste liquid to the ozone treatment tank 22.

[0128] (Step St93: Ozone gas supply process) Next, the ozone generator 23 generates high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26, and supplies the generated high-concentration ozone gas to the ozone treatment tank 22.

[0129] (Step St94: Ozone treatment process) The coating waste liquid supplied from the waste liquid tank 12A of the coating booth 10A is ozone-treated by the high-concentration ozone gas supplied from the ozone generator 23 in the ozone treatment tank 22, and becomes ozone-treated water containing purified water and unreacted ozone gas. In the said ozone treatment, the surplus paint in the coating waste liquid is decomposed into water and gas (such as oxygen and carbon dioxide) by ozone gas. The ozone-treated water is supplied to the degassing tank 91.

[0130] (Step St95: Degassing process) Next, in the degassing tank 91, ozone gas is degassed from the ozone-treated water supplied from the ozone treatment tank 22. The ozone gas separated from the ozone-treated water flows into the ozone decomposer 25, is decomposed into oxygen, and is discharged to the atmosphere.

[0131] (Step St96: Has a detection signal been obtained from the liquid level detection sensor S1?) Next, the controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S1. When it is determined by the controller 28 that the processing device 100 has not obtained a detection signal from the liquid level detection sensor S1 (NO in Step St96), until the controller 28 obtains a detection signal from the liquid level detection sensor S1 (until the purified water in the degassing tank 91 reaches a predetermined water level), the previous steps St92 to 95 are executed again.

[0132] (Step St97: Start the return pump 29A) On the other hand, when the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S1 (YES in step St96), it activates the return pump 29A. The return pump 29A sucks the purified water stored in the degassing tank 91 and returns the sucked purified water to the waste liquid tank 12A of the painting booth 10A.

[0133] (Step St98: Has a detection signal been acquired from the liquid level detection sensor S2?) The controller 28 determines whether or not it has acquired a detection signal from the liquid level detection sensor S2.

[0134] (Step St99: Stop the return pump 29A) When the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S2 (YES in step St98), it stops the return pump 29A.

[0135] (Step St100: Has a predetermined time elapsed?) The controller 28 determines whether or not a predetermined time has elapsed since the waste liquid recovery pump 21A was activated. Specifically, the controller 28 determines whether the time interval T1 (T1 = t2 - t1) between the activation time t1 of the waste liquid recovery pump 21A and the current time t2 is equal to a time interval (hereinafter referred to as the set time) preset by the operator of the processing apparatus 100. The set time may be arbitrarily set by the operator.

[0136] (Step St101: Has a stop instruction been input?) When the controller 28 determines that a predetermined time has not elapsed since the waste liquid recovery pump 21A was activated (determines that the time interval T1 is not the set time) (NO in step St100), it determines whether or not an instruction to stop the operation of the processing apparatus 100 has been input from the operator of the processing apparatus 100. When it is determined by the controller 28 that an instruction to stop the processing device 100 has not been input from the operator of the processing device 100 (NO in step St101), the previous steps St92 to St99 are executed again. The processing device 100 repeats the purification cycle (hereinafter referred to as the first purification cycle) of the previous steps St92 to St99 until a predetermined time elapses after the waste liquid recovery pump 21A is started (until the time interval T1 becomes the set time), or until an instruction to stop the operation of the processing device 100 is input from the operator of the processing device 100.

[0137] (Step S102: Operation Stop) When the controller 28 determines that an instruction to stop the operation of the processing device 100 has been input from the operator of the processing device 100 (YES in step St101), the controller 28 outputs a stop signal to the waste liquid recovery pump 21A, the ozone generator 23, and the compressed air supply device 227 (the painting compressor 227a or the built-in compressor 227b). These devices that have acquired the stop signal from the controller 28 stop operating. Thereby, the operation of the processing device 100 stops.

[0138] (Step St103: Stop of Waste Liquid Recovery Pump 21A) When the controller 28 determines that a predetermined time has elapsed since the waste liquid recovery pump 21A was started (determines that the time interval T1 has become the set time) (YES in step St100), the controller 28 stops the waste liquid recovery pump 21A.

[0139] (Step St104: Start of Waste Liquid Recovery Pump 21B) The controller 28 starts the waste liquid recovery pump 21B.

[0140] (Step St105: Suction Process) The waste liquid recovery pump 21B sucks the painting waste liquid stored in the waste liquid tank 12B of the painting booth 10B and supplies the sucked painting waste liquid to the ozone treatment tank 22.

[0141] (Step St106: Ozone Gas Supply Process) The ozone generator 23 generates high-concentration ozone gas from the high-concentration oxygen gas supplied from the oxygen concentrator 26, and supplies the generated high-concentration ozone gas to the ozone treatment tank 22.

[0142] (Step St107: Ozone treatment process) The coating waste liquid supplied from the waste liquid tank 12B is ozone-treated in the ozone treatment tank 22 by the high-concentration ozone gas supplied from the ozone generator 23, and becomes ozone-treated water containing purified water and unreacted ozone gas. In this ozone treatment, the excess paint in the coating waste liquid is decomposed into water and gas (such as oxygen and carbon dioxide) by the ozone gas. The ozone-treated water is supplied to the degassing tank 24.

[0143] (Step St108: Degassing process) In the degassing tank 91, ozone gas is degassed from the ozone-treated water supplied from the ozone treatment tank 22. The ozone gas separated from the ozone-treated water flows into the ozone decomposer 25 and is decomposed into oxygen, which is then released into the atmosphere.

[0144] (Step St109: Has a detection signal been obtained from the liquid level detection sensor S1?) The controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S1. When the processing device 100 is determined by the controller 28 that a detection signal has not been obtained from the liquid level detection sensor S1 (NO in step St109), the previous steps St105 to St108 are executed again until the controller 28 obtains a detection signal from the liquid level detection sensor S1 (until the purified water in the degassing tank 91 reaches a predetermined water level).

[0145] (Step St110: Start the return pump 29B) On the other hand, when the controller 28 determines that a detection signal has been obtained from the liquid level detection sensor S1 (YES in step St109), the return pump 29B is started. The return pump 29B sucks the purified water stored in the degassing tank 91 and returns the sucked purified water to the waste liquid tank 12B of the painting booth 10B.

[0146] (Step St111: Has a detection signal been obtained from the liquid level detection sensor S2?) The controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S2.

[0147] (Step St112: Stop the return pump 29B) When the controller 28 determines that a detection signal has been obtained from the liquid level detection sensor S2 (YES in Step St111), the controller 28 stops the return pump 29B.

[0148] (Step St113: Has a predetermined time elapsed?) The controller 28 determines whether or not a predetermined time has elapsed since the waste liquid recovery pump 21B was started. Specifically, the controller 28 determines whether or not the time interval T2 (T = t4 - t3) between the start time t3 of the waste liquid recovery pump 21B and the current time t4 has reached the set time.

[0149] (Step St114: Has a stop instruction been input?) When the controller 28 determines that a predetermined time has not elapsed since the waste liquid recovery pump 21B was started (determines that the time interval T2 is not the set time) (NO in Step St113), the controller 28 determines whether or not an instruction to stop the operation of the processing device 100 has been input from the operator of the processing device 100. When the controller 28 of the processing device 100 determines that an instruction to stop the processing device 100 has not been input from the operator of the processing device 100 (NO in Step St114), the processing device 100 executes the previous steps St105 to St112 again. The processing device 100 repeats the purification cycle of the previous steps St105 to St112 (hereinafter referred to as the second purification cycle) until a predetermined time elapses after the waste liquid recovery pump 21B is started (until the time interval T2 reaches the set time), or until an instruction to stop the operation of the processing device 100 is input from the operator of the processing device 100.

[0150] (Step S115: Stop the operation) When the controller 28 determines that an instruction to stop the operation of the processing device 100 has been input from the operator of the processing device 100 (YES in step St114), the controller 28 outputs a stop signal to the waste liquid recovery pump 21B, the ozone generator 23, and the compressed air supply device 227 (the painting compressor 227a or the built-in compressor 227b). These devices that have received the stop signal from the controller 28 stop operating. Thereby, the operation of the processing device 100 stops.

[0151] (Step St116: Stop the waste liquid recovery pump 21B) When the controller 28 determines that a predetermined time has elapsed since the waste liquid recovery pump 21B was started (it is determined that the time interval T2 has reached the set time) (YES in step St113), the controller 28 stops the waste liquid recovery pump 21B.

[0152] As understood from the description of the operation of the processing device 100 above and the flowcharts shown in FIGS. 22 and 23, the processing device 100 according to the ninth embodiment can mutually switch between the first purification cycle and the second purification cycle under the control of the controller 28.

[0153] Generally, when the amount of the painting waste liquid stored in the waste liquid tank is small, the amount of sludge generated in the waste liquid tank also becomes small. Thereby, the processing device 100 can sufficiently purify the painting waste liquid stored in the waste liquid tank without always executing the purification cycle. That is, if the painting waste liquid stored in the waste liquid tank is sufficiently purified, the processing device 100 does not need to execute the purification cycle for purifying the waste liquid tank. Therefore, the processing device 100 according to the ninth embodiment can also purify the painting waste liquid stored in another waste liquid tank by executing the other purification cycle while either one of the first and second purification cycles is not being executed.

[0154] As described above, the processing apparatus 100 according to the ninth embodiment can switch between the first purification cycle and the second purification cycle. Therefore, with a single processing apparatus 100, it is possible to purify the coating waste liquid stored in the waste liquid tank 12A and the coating waste liquid stored in the waste liquid tank 12B, eliminating the need to introduce a plurality of coating waste liquid processing apparatuses corresponding to each of the waste liquid tanks 12A and 12B. As a result, compared with the case of introducing a plurality of coating waste liquid processing apparatuses, the introduction cost of the apparatus for purifying the coating waste liquid stored in the waste liquid tank 12A and the coating waste liquid stored in the waste liquid tank 12B can be significantly reduced. That is, in the ninth embodiment, since the processing apparatus 100 can switch between the first purification cycle and the second purification cycle, the introduction cost of the apparatus for purifying a plurality of waste liquid tanks can be suppressed, and the labor and cost required for the maintenance and management of the waste liquid tanks 12A and 12B can be reduced.

[0155] <<Tenth Embodiment>> Next, a tenth embodiment of the present invention will be described. In the following description of the tenth embodiment, the same components as those in the first to ninth embodiments may be denoted by the same reference numerals, and the description thereof may be omitted or simplified.

[0156] [Configuration of Coating Waste Liquid Treatment System] FIG. 24 is a schematic diagram showing a configuration example of a coating waste liquid treatment system 101 according to the tenth embodiment. The coating waste liquid treatment system 101 includes a coating booth 10 and a coating waste liquid treatment apparatus 110 (hereinafter referred to as the treatment apparatus 110).

[0157] [Coating Waste Liquid Treatment Apparatus] The treatment apparatus 110 includes a waste liquid recovery pump 21, an ozone treatment tank 22, an ozone generator 23, a deaeration tank 91, an ozone decomposer 25, a return pump 29, a controller 28, an oxygen concentrator 26, a compressed air supply device 227, a backflow detection sensor 41, a re-supply pump 51, a deterioration index unit 61, an ozone concentration measurement device 71, a bubble sensor 81, and a tray T.

[0158] The tray T is arranged vertically below the degassing tank 91 and is a container interposed between the degassing tank 91 and the ground. The capacity of the tray T is not particularly limited, but it is preferably larger than the capacity of the degassing tank 91.

[0159] As shown in FIG. 24, the tray T has a liquid level detection sensor S3. The liquid level detection sensor S3 is electrically connected to the controller 28. The liquid level detection sensor S3 detects the liquid level of the liquid leaked from the degassing tank 91 and stored in the tray T, and outputs a detection signal to the controller 28.

[0160] <Operation of the coating waste liquid treatment device> FIG. 25 is a flowchart showing an example of the operation of the treatment device 110. Hereinafter, an example of the operation of the treatment device 110 will be described with appropriate reference to FIG. 25.

[0161] (Step St201: Has a detection signal been obtained from the liquid level detection sensor S3?) The controller 28 determines whether or not a detection signal has been obtained from the liquid level detection sensor S3. When the controller 28 determines that a detection signal has not been obtained from the liquid level detection sensor S3 (NO in step St201), the treatment device 110 executes the previous step St10.

[0162] (Step St202: Operation stop) When the controller 28 determines that it has acquired a detection signal from the liquid level detection sensor S3 (YES in step St201), or when it determines that an instruction to stop the operation of the processing device 110 has been input from the operator of the processing device 110 (YES in step St10), the controller 28 outputs a stop signal to the waste liquid recovery pump 21, the ozone generator 23, and the compressed air supply device 227 (the painting compressor 227a or the built-in compressor 227b). These devices that have acquired the stop signal from the controller 28 stop operating. That is, the operation of the processing device 110 stops. As a result, it is possible to prevent purified water or ozone-treated water from continuously leaking from the deaeration tank 91. Since the leaked liquid accumulates in the tray T, it is possible to prevent the ground from being flooded. For this reason, it is possible to eliminate accidents such as the operator of the processing device 110 falling due to the flooded ground.

[0163] 2. Supplementary As described above, the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to such examples. It is obvious that those having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modification examples or correction examples within the scope of the technical idea described in the claims. Naturally, these are also understood to belong to the technical scope of the present invention.

[0164] For example, the painting waste liquid treatment devices 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 exemplified in the above embodiments are devices for purifying painting waste including surplus paint, but are not limited thereto. For example, the painting waste liquid treatment devices 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 may be devices for purifying painting waste liquid different from the said painting waste liquid, and the use of the present invention is not particularly limited.

[0165] In addition, although the painting booth exemplified in the above embodiment has a circulation pump, it is not limited thereto. For example, the painting booth may be a pump-less type painting booth in which the circulation pump is omitted. In this case, a vinyl sheet is attached to the surface of the overspray paint receiver that receives the excess paint. When excess paint accumulates on the vinyl sheet, an operator of the painting booth may peel off the vinyl sheet from the surface.

[0166] Furthermore, in the paint waste liquid treatment system 9 exemplified in the above ninth embodiment, the number of waste liquid tanks is two, but it is not limited thereto. For example, the paint waste liquid treatment system 9 may have n waste liquid tanks, n waste liquid recovery pumps corresponding to each of the n waste liquid tanks, and n return pumps corresponding to each of the n waste liquid tanks, and may be configured such that the purification cycles are switched mutually among the n waste liquid tanks (n is a natural number of 3 or more).

[0167] In addition, the effects described in this specification are not limited. That is, the present invention may exhibit other effects apparent to those skilled in the art from the description of this specification, together with or instead of the above effects.

[0168] 3. Supplementary Note The following aspects can be understood from the embodiments exemplified above.

[0169] A paint waste liquid treatment apparatus according to one aspect (Aspect 1) of the present invention includes a waste liquid recovery pump that sucks paint waste liquid stored in a waste liquid tank, an ozone treatment tank that performs ozone treatment on the paint waste liquid supplied from the waste liquid recovery pump, an ozone generator that generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank, a degassing tank that stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, an ozone decomposer that decomposes the ozone gas supplied from the degassing tank, a return pump that returns the purified water stored in the degassing tank to the waste liquid tank, and a controller that controls the waste liquid recovery pump, the return pump, and the ozone generator.

[0170] According to the above aspect, the coating waste liquid treatment device performs ozone treatment on the coating waste liquid supplied from the waste liquid tank, and by repeating the cycle of returning the purified water generated by the ozone treatment to the waste liquid tank, the cleaning liquid accumulated in the waste liquid tank can be made into purified water from which excess paint has been purified. As a result, there is no need to have a contractor collect the coating waste liquid containing excess paint as industrial waste as in the prior art, or to add chemicals such as preservatives and killer agents to the waste liquid tank to make it easier to recover the excess paint, and the labor and costs associated with the maintenance and management of the waste liquid tank can be significantly reduced compared to the past.

[0171] The coating waste liquid treatment device according to a specific example (Aspect 2) of Aspect 1 further includes an oxygen concentrator connected to the ozone generator for supplying oxygen gas to the ozone generator, a first compressor, a second compressor, a first flow path connected to the first compressor and the oxygen concentrator for guiding the air output from the first compressor to the oxygen concentrator, a second flow path connected to the second compressor and the oxygen concentrator for guiding the air output from the second compressor to the oxygen concentrator, and a switching mechanism for switching the communication / shut-off of the first and second flow paths, and the controller controls the switching mechanism.

[0172] The coating waste liquid treatment device according to a specific example (Aspect 3) of Aspect 2 further includes an air pressure detection sensor provided in the first flow path for detecting the internal pressure of the first flow path, and the switching mechanism shuts off the first flow path and communicates the second flow path based on the control of the controller that has acquired a detection signal from the air pressure detection sensor. According to Aspect 3, even if some abnormality occurs in the first compressor and the first compressor is stopped, the second compressor functions as a backup for the first compressor, so the supply of ozone gas to the ozone treatment tank can be continued without stopping.

[0173] The coating waste liquid treatment device according to a specific example (Aspect 4) of Aspect 2 further includes a backflow detection sensor connected to the ozone treatment tank and the ozone generator for detecting the backflow of ozone-treated water from the ozone treatment tank to the ozone generator.

[0174] The coating waste liquid treatment device according to the specific example of Aspect 4 (Aspect 5) stops based on the control of the controller that has acquired the detection signal of the backflow detection sensor. Thereby, it is possible to prevent the ozone generator from being damaged by the ozone-treated water flowing back from the ozone treatment tank and flowing into the ozone generator.

[0175] The coating waste liquid treatment device according to the specific example of Aspect 4 (Aspect 6) further includes a re-supply pump that re-supplies the purified water stored in the deaeration tank to the ozone treatment tank. The coating waste liquid treatment device according to Aspect 6 can purify the coating waste liquid without passing through the coating booth. Therefore, the operator in the coating booth can perform other operations (for example, cleaning inside the waste liquid tank, etc.) in parallel in the coating booth while purifying the coating waste liquid in the coating waste liquid treatment device, improving the labor productivity and work efficiency of the operator.

[0176] According to the specific example of Aspect 6 (Aspect 7), the ozone decomposer contains a catalyst that decomposes the ozone gas supplied from the deaeration tank. The coating waste liquid treatment device according to Aspect 7 further includes a deterioration index part that serves as an index of the degree of deterioration of the catalyst. The operator of the coating waste liquid treatment device according to Aspect 7 can grasp that the catalyst has been deactivated by checking the discoloration of the deterioration index part, and can know that it is necessary to replace the catalyst with a new catalyst.

[0177] The coating waste liquid treatment device according to the specific example of Aspect 7 (Aspect 8) further includes an ozone concentration measuring device that measures the ozone concentration of the gas discharged from the ozone decomposer.

[0178] The coating waste liquid treatment device according to the specific example of Aspect 8 (Aspect 9) stops based on the control of the controller that has acquired the measurement result of the ozone concentration measuring device. Thereby, it is possible to prevent ozone gas with a concentration equal to or higher than a predetermined concentration from being continuously discharged from the ozone decomposer, not only reducing the environmental load but also ensuring the safety of the operator of the treatment device.

[0179] The coating waste liquid treatment apparatus according to a specific example of Aspect 8 (Aspect 10) further includes a bubble sensor that detects bubbles of ozone gas contained in the ozone-treated water.

[0180] The coating waste liquid treatment apparatus according to a specific example of Aspect 10 (Aspect 11) stops based on the control of the controller that has acquired the detection signal of the bubble sensor. Thereby, even when the inflow of the ozone-treated water from the ozone treatment tank to the degassing tank is fast and the ozone-treated water rapidly accumulates in the degassing tank, the water level of the ozone-treated water in the degassing tank is maintained below a predetermined level, and it is possible to prevent the ozone-treated water from overflowing from the degassing tank or flowing back to the ozone decomposer.

[0181] According to a specific example of Aspect 10 (Aspect 12), the degassing tank includes a housing that stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, an inspection window that is attached to the housing and allows the inside of the housing to be visually inspected from the outside, and a seal member that is interposed between the housing and the inspection window and seals an internal space defined by the inner surface of the housing and the inner surface of the inspection window. Thereby, it is possible to prevent the purified water and ozone-treated water stored in the housing and the ozone gas degassed from the ozone-treated water in the degassing tank from leaking to the outside.

[0182] According to a specific example of any one of Aspects 1 to 12 (Aspect 13), the waste liquid tank has a first waste liquid tank and a second waste liquid tank, the waste liquid recovery pump has a first recovery pump and a second recovery pump, the return pump has a first return pump and a second return pump, the first recovery pump supplies the coating waste liquid stored in the first waste liquid tank to the ozone treatment tank, the second recovery pump supplies the coating waste liquid stored in the second waste liquid tank to the ozone treatment tank, the first return pump returns the purified water stored in the degassing tank to the first waste liquid tank, and the second return pump returns the purified water stored in the degassing tank to the second waste liquid tank.

[0183] According to a specific example of Aspect 13 (Aspect 14), the controller executes control to switch between a first purification cycle in which the coating waste liquid stored in the first waste liquid tank is purified by circulating through the first recovery pump, the ozone treatment tank, the deaeration tank, and the first return pump, and a second purification cycle in which the coating waste liquid stored in the second waste liquid tank is purified by circulating through the second recovery pump, the ozone treatment tank, the deaeration tank, and the second return pump. According to Aspect 14, the coating waste liquid treatment device can switch between the first purification cycle and the second purification cycle. Therefore, with a single coating waste liquid treatment device, it is possible to purify the coating waste liquid stored in the first waste liquid tank and the coating waste liquid stored in the second waste liquid tank, eliminating the need to introduce a plurality of coating waste liquid treatment devices corresponding to each of the first and second waste liquid tanks. As a result, compared with the case of introducing a plurality of coating waste liquid treatment devices, the cost of purifying the coating waste liquid stored in the first waste liquid tank and the coating waste liquid stored in the second waste liquid tank can be significantly reduced. That is, in Aspect 14, since the coating waste liquid treatment device can switch between the first purification cycle and the second purification cycle, the introduction cost of the device for purifying a plurality of waste liquid tanks can be suppressed, and the labor and cost associated with the maintenance and management of the first and second waste liquid tanks can be reduced.

[0184] A coating waste liquid treatment system according to one aspect of the present invention (Aspect 15) includes a coating booth having a waste liquid tank for storing coating waste liquid containing excess paint, a waste liquid recovery pump for sucking the coating waste liquid, an ozone treatment tank for subjecting the coating waste liquid supplied from the waste liquid recovery pump to ozone treatment, an ozone generator for generating ozone gas from oxygen gas and supplying the generated ozone gas to the ozone treatment tank, a deaeration tank for storing purified water from which ozone gas has been deaerated from the ozone-treated water supplied from the ozone treatment tank, an ozone decomposer for decomposing the ozone gas supplied from the deaeration tank, a return pump for returning the purified water stored in the deaeration tank to the waste liquid tank, and a coating waste liquid treatment device having a controller for controlling the waste liquid recovery pump, the return pump, and the ozone generator. According to Aspect 15, the coating waste liquid treatment device performs ozone treatment on the coating waste liquid supplied from the waste liquid tank, and by repeating the cycle of returning the purified water generated by the ozone treatment to the waste liquid tank, the cleaning liquid accumulated in the waste liquid tank can be made into purified water from which excess paint has been purified. As a result, there is no need to have the coating waste liquid containing excess paint collected by a contractor as industrial waste as in the past, or to add chemicals such as preservatives and killer agents to the waste liquid tank to make it easier to collect the excess paint, and the labor and cost required for the maintenance and management of the waste liquid tank can be significantly reduced compared to before.

[0185] A coating waste liquid treatment method according to one aspect (Aspect 16) of the present invention includes a suction step in which a waste liquid recovery pump sucks the coating waste liquid stored in a waste liquid tank, an ozone treatment step in which an ozone treatment tank performs ozone treatment on the coating waste liquid supplied from the waste liquid recovery pump, an ozone gas supply step in which an ozone generator generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank, a degassing step in which a degassing tank stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, an ozone decomposer decomposes the ozone gas supplied from the degassing tank, and a return step in which a return pump returns the purified water stored in the degassing tank to the waste liquid tank, and executes a purification cycle through the suction step, the ozone treatment step, the ozone gas supply step, the degassing step, and the return step. According to Aspect 16, ozone treatment is performed on the coating waste liquid supplied from the waste liquid tank, and the cycle in which the purified water generated by the ozone treatment is returned to the waste liquid tank is repeated, so that the cleaning liquid accumulated in the waste liquid tank can be made into purified water from which excess paint has been purified. As a result, there is no need to have the coating waste liquid containing excess paint collected by a contractor as industrial waste as in the past, or to add chemicals such as preservatives and killer agents to the waste liquid tank to make it easier to collect the excess paint, and the labor and cost required for the maintenance and management of the waste liquid tank can be significantly reduced compared to before.

Description of Signs

[0186] 1 to 9, 101... Coating waste liquid treatment system 10, 10A, 10B... Painting Booth 12A... Waste Liquid Tank (First Waste Liquid Tank) 12B... Waste Liquid Tank (Second Waste Liquid Tank) 20, 30, 40, 50, 60, 70, 80, 90, 100, 110... Painting Waste Liquid Treatment Device 21... Waste Liquid Recovery Pump 21A... Recovery Pump (First Recovery Pump) 21B... Recovery Pump (Second Recovery Pump) 22... Ozone Treatment Tank 23... Ozone Generator 24, 91... Degassing Tank 25... Ozone Decomposer 25C... Catalyst 26... Oxygen Concentrator 28... Controller 29... Return Pump 29A... Return Pump (First Return Pump) 29B... Return Pump (Second Return Pump) 41... Backflow Detection Sensor 51... Resupply Pump 61... Deterioration Index Section 71... Ozone Concentration Meter 81... Bubble Sensor 91a... Housing of Degassing Tank 91b... Inspection Window 91c... Sealing Member 227... Compressed Air Supply Device 227a... Compressor for Painting (First Compressor) 227b... Built-in Compressor (Second Compressor) 227c... Three-way Valve (Switching Mechanism) 227e... Air Pressure Detection Sensor R2 and R3... Flow Path (First Flow Path) R1 and R3... Flow Path (Second Flow Path)

Claims

1. A waste liquid recovery pump for sucking the coating waste liquid stored in the waste liquid tank, An ozone treatment tank for subjecting the coating waste liquid supplied from the waste liquid recovery pump to ozone treatment, An ozone generator for generating ozone gas from oxygen gas and supplying the generated ozone gas to the ozone treatment tank, A degassing tank for storing purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, An ozone decomposer for decomposing the ozone gas supplied from the degassing tank, A return pump for returning the purified water stored in the degassing tank to the waste liquid tank, And a controller for controlling the waste liquid recovery pump, the return pump, and the ozone generator A coating waste liquid treatment apparatus comprising.

2. An oxygen concentrator connected to the ozone generator for supplying oxygen gas to the ozone generator, A first compressor, A second compressor, A first flow path connected to the first compressor and the oxygen concentrator for guiding the air output from the first compressor to the oxygen concentrator, A second flow path connected to the second compressor and the oxygen concentrator for guiding the air output from the second compressor to the oxygen concentrator, And a switching mechanism for switching the communication / shutoff of the first and second flow paths Further comprising, The controller controls the switching mechanism, The coating waste liquid treatment apparatus according to Claim 1.

3. Further comprising an air pressure detection sensor provided in the first flow path for detecting the internal pressure of the first flow path, The switching mechanism shuts off the first flow path and communicates the second flow path based on the control of the controller that has acquired a detection signal from the air pressure detection sensor, The coating waste liquid treatment apparatus according to Claim 2.

4. Further comprising a backflow detection sensor connected to the ozone treatment tank and the ozone generator for detecting backflow of the ozone-treated water from the ozone treatment tank to the ozone generator, The coating waste liquid treatment apparatus according to Claim 2.

5. The coating waste liquid treatment apparatus according to Claim 4, which stops based on the control of the controller that has acquired the detection signal of the backflow detection sensor.

6. Further comprising a re-supply pump for re-supplying the purified water stored in the degassing tank to the ozone treatment tank, The coating waste liquid treatment apparatus according to Claim 4.

7. The ozone decomposer contains a catalyst for decomposing the ozone gas supplied from the degassing tank, Further comprising a deterioration index portion serving as an index of the degree of deterioration of the catalyst, The coating waste liquid treatment device according to claim 6.

8. Further comprising an ozone concentration measuring device for measuring the ozone concentration of the gas discharged from the ozone decomposer. The coating waste liquid treatment device according to claim 7.

9. The coating waste liquid treatment device according to claim 8, which stops based on the control of the controller that has obtained the measurement result of the ozone concentration measuring device.

10. Further comprising a bubble sensor for detecting bubbles of ozone gas contained in the ozone-treated water. The coating waste liquid treatment device according to claim 8.

11. The coating waste liquid treatment device according to claim 10, which stops based on the control of the controller that has obtained the detection signal of the bubble sensor.

12. The degassing tank A housing for storing purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank; An inspection window attached to the housing and allowing visual inspection of the inside of the housing from the outside; A seal member interposed between the housing and the inspection window and sealing an internal space defined by the inner surface of the housing and the inner surface of the inspection window. The coating waste liquid treatment device according to claim 10.

13. The waste liquid tank has a first waste liquid tank and a second waste liquid tank. The waste liquid recovery pump has a first recovery pump and a second recovery pump. The return pump has a first return pump and a second return pump. The first recovery pump supplies the coating waste liquid stored in the first waste liquid tank to the ozone treatment tank. The second recovery pump supplies the coating waste liquid stored in the second waste liquid tank to the ozone treatment tank. The first return pump returns the purified water stored in the degassing tank to the first waste liquid tank. The second return pump returns the purified water stored in the degassing tank to the second waste liquid tank. The coating waste liquid treatment device according to any one of claims 1 to 12.

14. The controller A first purification cycle in which the coating waste liquid stored in the first waste liquid tank is purified by circulating through the first recovery pump, the ozone treatment tank, the degassing tank, and the first return pump; A second purification cycle in which the coating waste liquid stored in the second waste liquid tank is purified by circulating through the second recovery pump, the ozone treatment tank, the degassing tank, and the second return pump. The coating waste liquid treatment device according to claim 13, which executes control to switch between them mutually.

15. A painting booth having a waste liquid tank for storing coating waste liquid containing excess paint; A waste liquid recovery pump for sucking the coating waste liquid An ozone treatment tank that performs ozone treatment on the coating waste liquid supplied from the waste liquid recovery pump, An ozone generator that generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank, A degassing tank that stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, An ozone decomposer that decomposes the ozone gas supplied from the degassing tank, A return pump that returns the purified water stored in the degassing tank to the waste liquid tank, and A controller that controls the waste liquid recovery pump, the return pump, and the ozone generator A coating waste liquid treatment apparatus having the above components A coating waste liquid treatment system comprising the above components.

16. A suction step in which a waste liquid recovery pump sucks the coating waste liquid stored in a waste liquid tank, An ozone treatment step in which an ozone treatment tank performs ozone treatment on the coating waste liquid supplied from the waste liquid recovery pump, An ozone gas supply step in which an ozone generator generates ozone gas from oxygen gas and supplies the generated ozone gas to the ozone treatment tank, A degassing step in which a degassing tank stores purified water from which ozone gas has been degassed from the ozone-treated water supplied from the ozone treatment tank, A step in which an ozone decomposer decomposes the ozone gas supplied from the degassing tank, A return step in which a return pump returns the purified water stored in the degassing tank to the waste liquid tank, and the method includes A purification cycle is executed through the suction step, the ozone treatment step, the ozone gas supply step, the degassing step, and the return step, A method for treating coating waste liquid.

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