JP2022173501A - Coating film peeling method of cleaning object and coating film peeling device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating film peeling method of a cleaning object which can obtain a high coating film peeling effect in a simple constitution and a coating film peeling device.

SOLUTION: At first, by heating and compressing water and air and/or carbon dioxide, a gas liquid mixed fluid the water of which is in a subcritical state, and the air and/or carbon dioxide of which is in a supercritical state is produced (S101). Next, the produced gas liquid mixed fluid is sprayed to a cleaning object under a normal temperature normal pressure the surface of which has a coating film (S102). Thereby, the coating film is peeled.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a cleaning method and cleaning apparatus for cleaning various objects to be cleaned such as concrete structures and vehicles.

Conventionally, a cleaning method using cleaning water containing fine bubbles such as microbubbles and nanobubbles has been proposed (see Patent Documents 1 and 2). In such a cleaning method, fine bubbles that have adsorbed dirt on the object to be cleaned are separated from the object to be cleaned, or the impact caused by the crushing of the fine bubbles removes the dirt, thereby realizing effective cleaning. .

JP 2010-104903 A JP 2013-188732 A

However, since the microbubbles disappear at high temperatures, the above-described conventional technique can only use cleaning water at a relatively low temperature, such as room temperature or below, and the cleaning effect may not be sufficient.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and a main object thereof is to provide a cleaning method and a cleaning apparatus capable of solving the above problems.

In order to solve the above-described problems, one aspect of the cleaning method of the present invention provides a gas-liquid mixed fluid in which water and gas are heated and pressurized, and the water is in a subcritical state and the gas is in a supercritical state. is generated, and the generated gas-liquid mixed fluid is jetted against the object to be cleaned under normal temperature and normal pressure.

In the above aspect, the gas is preferably air and/or carbon dioxide.

Further, in the above aspect, the generated gas-liquid mixed fluid may be jetted against the object to be cleaned having a coating film formed thereon to remove the coating film.

In the above aspect, a metal complex may be added to the gas-liquid mixed fluid, and the object to be cleaned may be a concrete structure.

Moreover, in the above aspect, the object to be cleaned may be a vehicle.

Further, a cleaning apparatus according to one aspect of the present invention includes a generation unit that heats and pressurizes water and gas to generate a gas-liquid mixed fluid in which the water is in a subcritical state and the gas is in a supercritical state; and an injection unit for injecting the gas-liquid mixed fluid generated by the generation unit onto an object to be cleaned under normal temperature and normal pressure.

According to the present invention, a high cleaning effect can be obtained with a simple configuration.

1 is a diagram schematically showing the configuration of a cleaning apparatus according to Embodiment 1; FIG. FIG. 2 is a block diagram showing the main configuration of the washing device main body of Embodiment 1; 4 is a flow chart showing the operation flow of the cleaning apparatus of Embodiment 1; FIG. 5 is a block diagram showing the main configuration of a modification of the cleaning device main body of Embodiment 1; FIG. 5 is a block diagram showing the main configuration of a modification of the cleaning device main body of Embodiment 1; FIG. 5 is a block diagram showing the main configuration of a modification of the cleaning device main body of Embodiment 1; FIG. 4 is a diagram schematically showing the configuration of a cleaning apparatus according to Embodiment 2;

Preferred embodiments of the present invention will be described below with reference to the drawings. It should be noted that each of the embodiments shown below exemplifies a method and apparatus for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following. do not have. Various modifications can be made to the technical idea of the present invention within the technical scope described in the claims.

In the cleaning method of the present embodiment, the gas-liquid mixed fluid is used to clean the surface of the object to be cleaned. Examples of objects to be washed include various structures such as concrete structures and bridges, various vehicles such as automobiles, ships, aircraft, and various machines such as food processing machines, but are not limited to specific ones. does not mean An example of cleaning the surface of a structure will be described below.

(Configuration of cleaning device)
FIG. 1 is a diagram schematically showing the configuration of a cleaning apparatus according to this embodiment. As shown in FIG. 1 , the cleaning device 1 includes a cleaning device main body 2 , an injection nozzle 3 , and a connection hose 4 that connects the cleaning device main body 2 and the injection nozzle 3 .

As will be described later, in the cleaning device main body 2, a gas-liquid mixed fluid in which water and gas are mixed is generated. The gas-liquid mixed fluid generated in the washing device main body 2 is supplied to the injection nozzle 3 through the connection hose 4 by the action of the pressure pump 22, and is discharged from the opening provided at the tip of the injection nozzle 3. , is jetted against the structure 100, which is an object to be cleaned. At this time, the gas-liquid mixed fluid is jetted so as to spread radially from the opening of the jet nozzle 3, as indicated by reference numeral 101 in FIG.

In order to suppress the temperature drop of the gas-liquid mixed fluid, the connection hose 4 may be wound with a heat insulating material, a sheet-like heater, or the like.

FIG. 2 is a block diagram showing the main configuration of the washing device main body 2. As shown in FIG. As shown in FIG. 2 , the washing device body 2 includes a water storage tank 21 , a pressure pump 22 , a first tank 23 , a second tank 24 , an air tank 25 and a carbon dioxide tank 26 .

The water storage tank 21 stores water supplied from an external water supply facility or the like. The water stored in the water storage tank 21 in this manner is pressurized by the pressure pump 22 and sent out to the first tank 23 side.

The 1st tank 23 and the 2nd tank 24 are tanks which store pressurized water, and comprise a pressure vessel. The first tank 23 and the second tank 24 have heaters therein, and the heaters can be used to heat the stored pressurized water.

Air tank 25 and carbon dioxide tank 26 store air and carbon dioxide, respectively. These air and carbon dioxide are pressurized into the connecting pipe between the first tank 23 and the second tank 24 via an electromagnetic valve or the like (not shown). It should be noted that instead of supplying the gas from the tank as described above, for example, the gas may be supplied from a cylinder or the like.

(Operation of cleaning device)
Next, the operation of the cleaning apparatus 1 configured as described above will be described with reference to a flow chart.
FIG. 3 is a flow chart showing the operation flow of the cleaning device 1 of this embodiment. As shown in FIG. 3, the cleaning apparatus 1 first generates a gas-liquid mixed fluid, which is a cleaning fluid (S101), and then injects the gas-liquid mixed fluid onto an object to be cleaned under normal temperature and normal pressure. (S102). The details of each of these processes will be described below.

[Generation of gas-liquid mixed fluid (S101)]
In the present embodiment, water, air, and carbon dioxide are heated and pressurized to generate a gas-liquid mixed fluid in which water is in a subcritical state and air and carbon dioxide are in a supercritical state. In this specification, the term "supercritical state" means a state in which both the temperature and pressure are above the critical point, and the term "subcritical state" means that at least one of the temperature and pressure is below the critical point, It means a state under high temperature and high pressure.

The critical temperatures and critical pressures of water, air, and carbon dioxide, which are components of the gas-liquid mixed fluid used in this embodiment, are shown in Table 1 below.

In the present embodiment, the temperature of the gas-liquid mixed fluid generated in the cleaning apparatus main body 2 is set to about 200° C. in order to bring water into a subcritical state and air and carbon dioxide into a supercritical state. The pressure of this gas-liquid mixed fluid is set to approximately 3.77 MPa or more to maintain at least the supercritical state of air, and to 7.38 MPa or more to maintain the supercritical state of carbon dioxide.

The details of the procedure for generating the gas-liquid mixed fluid are as follows. First, the water stored in the water storage tank 21 is pressurized to a predetermined pressure by the pressure pump 22 and sent to the first tank 23 . The first tank 23 heats the pressurized water supplied from the pressurizing pump 22 to a predetermined temperature such as 80° C. and stores it.

The pressurized water stored in the first tank 23 is delivered to the second tank 24 by the action of the pressurization pump 22 . At that time, air and carbon dioxide are pressurized from the air tank 25 and the carbon dioxide tank 26 into the pipe connecting the first tank 23 and the second tank 24 . As a result, the pressurized water flowing from the first tank 23 to the second tank 24 is mixed with air and carbon dioxide to generate a gas-liquid mixed fluid.

The second tank 24 heats the gas-liquid mixed fluid produced as described above to about 200° C. and stores it. Further, the pressure of the gas-liquid mixed fluid stored in the second tank 24 is set to approximately 3.77 MPa or more by the action of the pressure pump 22 . As a result, a gas-liquid mixed fluid in which water is in a subcritical state and air is in a supercritical state is obtained. In order to obtain a gas-liquid mixed fluid in which carbon dioxide is also in a supercritical state, the pressure is set to 7.38 MPa or higher.

When air and carbon dioxide are mixed with water as described above, it is preferable to suppress the occurrence of cavitation as much as possible. Although the technique is not particularly limited, for example, there is a technique for miniaturizing bubbles by mixing the fluid while applying a shearing force to the fluid. As a mixing device for realizing this technique, for example, Ramond Nano Mixer (registered trademark) manufactured by Nanox Co., Ltd. can be cited.

[Injection of gas-liquid mixed fluid (S102)]
The cleaning device 1 injects the gas-liquid mixed fluid generated as described above from the opening of the injection nozzle 3 onto the surface of the structure 100 (S102).

The pressure (injection pressure) of the pressurized hot water injected from the injection nozzle 3 varies depending on the flow rate (discharge amount). When the flow rate is 15 L / min, the range of 5 to 22.5 MPa is preferable, and when the flow rate is less than that, the range of 0.1 to 5 MPa is preferred, and when it is higher and when a larger injection pressure is required. It is preferably 25 MPa or more.

The temperature and pressure of the gas-liquid mixed fluid injected to the structure 100 under normal temperature and pressure drop rapidly. Then, after reaching the surface of the structure 100, the water evaporates into water vapor. At this time, rapid volume expansion occurs due to the phase transition, and the pressure removes dirt adhering to the surface of the structure 100 .

Further, when the temperature of the gas-liquid mixed fluid released to normal temperature becomes lower than 140.7° C., which is the critical temperature of air, the air dissolved in the gas-liquid mixed fluid is separated to generate nanobubbles. As a result, the nanobubbles adsorb dirt on the surface of the structure 100 and separate it, and the impact caused by the crushing of the nanobubbles cleans the dirt.

Further, when the temperature of the gas-liquid mixed fluid further drops to below 31.1° C., which is the critical temperature of carbon dioxide, the carbon dioxide dissolved in the gas-liquid mixed fluid is separated to generate nanobubbles. This also produces a cleaning effect similar to that described above.

In addition, while air and carbon dioxide are in a supercritical state, they can be used as supercritical fluids. Since the supercritical fluid has extremely low surface tension, it penetrates into minute recesses formed on the surface of the structure 100 and removes dirt adhering to the inside thereof.

Each cleaning effect described above is instantaneous, but can be sustained by continuously injecting the gas-liquid mixed fluid. Thereby, a sufficient cleaning effect can be obtained.

If a coating film is formed on the surface of the object to be cleaned, the coating film can be removed by jetting the gas-liquid mixed fluid in step S102. In particular, when the temperature of the gas-liquid mixed fluid reaches 140.7° C. or higher when it reaches the surface of the object to be cleaned, that is, when air can be used as a supercritical fluid, the effect of removing the coating film is improved. . Therefore, if the object to be cleaned is a steel bridge or the like and the paint film needs to be peeled off, the temperature of the gas-liquid mixed fluid should be set to 140.7°C or higher when it reaches the surface of the object to be cleaned. is preferred. On the other hand, when the object to be washed is a vehicle or the like and it is necessary to avoid peeling of the paint film, it is preferable to set the temperature to be less than 140.7°C.

In the present embodiment, air and carbon dioxide are pressurized into the pipe connecting the first tank 23 and the second tank 24, but the position where these gases are introduced is not limited to this. For example, air and carbon dioxide may be introduced before the first tank 23 as shown in FIG. 4, and air and carbon dioxide may be introduced at the exit side of the second tank 24 as shown in FIG. You may Here, air and carbon dioxide do not have to be introduced from the same point, and may be introduced from separate points.

Moreover, in the present embodiment, the pressure pump 22 is provided between the water storage tank 21 and the first tank 23, but the pressure pump 22 may be provided at another position. For example, a pressure pump 22 may be provided between the first tank 23 and the second tank 24 . Also, the number of pressurizing pumps 22 is not limited to one. A pressure pump 22 may be provided.

In addition, in the present embodiment, the washing device main body 2 has two tanks, the first tank 23 and the second tank 24, as tanks for storing the pressurized water, but it may have one tank. FIG. 6 is a block diagram showing the main configuration of such a modification of the washing device main body 2. As shown in FIG. As shown in FIG. 6 , this cleaning device main body 2 does not have a first tank 23 , and water is sent from a water storage tank 21 to a second tank 24 by the action of a pressure pump 22 . An air tank 25 and a carbon dioxide tank 26 are connected to the piping between the pressure pump 22 and the second tank 24, and air and carbon dioxide are supplied from the air tank 25 and the carbon dioxide tank 26, respectively. It is press-fitted into the pipe. As a result, a gas-liquid mixed fluid is obtained, which is pressurized and stored in the second tank 24 in the same manner as described above. Even in this case, an excellent cleaning effect can be obtained as in the case described above. Also in this configuration, air and carbon dioxide may be introduced at the outlet side of the second tank 24 .

Gases such as air and carbon dioxide may be supplied directly into the second tank 24 instead of through the piping before the second tank 24 . However, in that case, cavitation may occur in the second tank 24, which may cause problems. Therefore, it is preferable to supply the gas into the pipe before the second tank 24 as described above.

Further, in the present embodiment, the gas-liquid mixed fluid is generated by dissolving air and carbon dioxide in water, but only one of air and carbon dioxide is dissolved in water to generate the gas-liquid mixed fluid. I don't mind.

As described above, in the washing apparatus 1 of the present embodiment, a vehicle such as an automobile can be used as an object to be washed in addition to the structure 100 . For example, by incorporating the washing device 1 into a gate-type car wash machine, it is possible to realize a car wash machine or the like that can obtain a high washing effect without using a brush.

(Embodiment 2)
In the case of Embodiment 1, the gas is introduced into the cleaning device main body 2 to generate the gas-liquid mixed fluid, but the present invention is not limited to this. In this embodiment, gas is introduced into the injection nozzle to generate a gas-liquid mixed fluid.

FIG. 7 is a diagram schematically showing the configuration of a cleaning apparatus according to Embodiment 2. FIG. As shown in FIG. 7, the cleaning device 10 includes a cleaning device main body 20, an injection nozzle 30, and a connection hose 4 that connects the cleaning device main body 20 and the injection nozzle 30 together. The configuration of the cleaning device main body 20 is the same as that of the cleaning device main body 2 of Embodiment 1 except that it does not have the air tank 25 and the carbon dioxide tank 26, so the description thereof is omitted.

The injection nozzle 30 has an injection port (not shown) and is configured to receive gas (air and/or carbon dioxide) from an external cylinder or the like through the injection port. The injection nozzle 30 mixes the gas received from the injection port with pressurized hot water received from the cleaning device main body 20 through the connection hose 4 to produce a gas-liquid mixed fluid similar to that of the first embodiment. to generate Then, the injection nozzle 30 injects the gas-liquid mixed fluid thus generated from the opening provided at the tip, thereby performing cleaning in the same manner as in the case of the first embodiment.

In addition, a nanobubble generator is provided inside the injection nozzle 30, and the gas is mixed with pressurized hot water by the nanobubble generator, and then the gas-liquid mixed fluid is injected from the opening to generate nanobubbles. You may make it promote generation|occurrence|production. As such a nanobubble generator, for example, a YJ nozzle manufactured by Aviro Vision Co., Ltd. can be exemplified.

(Other embodiments)
In each of the above embodiments, a metal complex may be added to the gas-liquid mixed fluid. For example, when a titanium complex is added to the gas-liquid mixed fluid, the surface of the object to be cleaned is cleaned by jetting the gas-liquid mixed fluid, and a protective layer containing titanium oxide can be formed on the surface. . Therefore, not only the cleaning but also the surface protection effect of the object to be cleaned can be expected. This is particularly effective when the object to be cleaned is a concrete structure.

The metal complex added to the gas-liquid mixed fluid may be other than the above titanium complex. Here, the metal complex refers to a complex containing precipitated nanoparticles of the metal that constitutes the complex, and also containing a water-soluble alkaline component such as sodium bicarbonate or NaOH. Specifically, metal complexes such as sodium silicate and potassium silicate can be used. In addition, Li ⁺ , Na ⁺ , K ⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Cd ²⁺ , Cu ²⁺ , Mn ²⁺ , Zn ²⁺ , La ³⁺ , Ni ^{2+ , Mg 2+ ,} Co ²⁺ , Fe ^{2+ ,} etc. Substitutionally active metal complexes and substitutionally inactive metal complexes such as Cr ³⁺ , Co ³⁺ , Ru ²⁺ , Rh ³⁺ , Ir ³⁺ and Pt ²⁺ can be used.

INDUSTRIAL APPLICABILITY The cleaning method and cleaning apparatus of the present invention are useful as a cleaning method and cleaning apparatus for structures such as concrete structures and bridges, vehicles and the like.

Reference Signs List 1, 10 cleaning device 2, 20 cleaning device main body 3, 30 injection nozzle 4 connection hose 21 water storage tank 22 pressure pump 23 first tank 24 second tank 25 air tank 26 carbon dioxide tank 100 structure

Claims (4)

Heating and pressurizing water and gas to generate a gas-liquid mixed fluid in which the water is in a subcritical state and the gas is in a supercritical state;
The generated gas-liquid mixed fluid is sprayed onto the object to be cleaned under normal temperature and pressure and having a coating film formed on the surface thereof to remove the coating film.
A method for stripping a coating film from an object to be cleaned. the gas is air;
jetting the gas-liquid mixed fluid onto the object to be cleaned so that the supercritical state of the gas is maintained when it reaches the surface of the object to be cleaned;
The method for removing a coating film from an object to be cleaned according to claim 1. The object to be cleaned is a steel bridge,
3. The method for removing a coating film from an object to be cleaned according to claim 1 or 2. a generation unit that heats and pressurizes water and gas to generate a gas-liquid mixed fluid in which the water is in a subcritical state and the gas is in a supercritical state;
an injection unit that injects the gas-liquid mixed fluid generated by the generation unit against the object to be cleaned and having a coating film formed on the surface thereof under normal temperature and normal pressure to peel off the coating film. Coating stripping equipment.

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