Cleaning method, cleaning device

Abstract

This invention provides a cleaning method that allows for the reduction of the size and installation area of ​​cleaning equipment, thereby lowering operating costs. [Solution] The cleaning method according to the present invention is characterized by comprising: a water displacement liquid injection step of injecting a water displacement liquid onto an object to be cleaned W in a cleaning tank 10; a cleaning liquid cleaning step of cleaning the object to be cleaned with a cleaning liquid in the cleaning tank 10 after the water displacement liquid injection step; and a cleaning liquid vaporization step of vaporizing the cleaning liquid.

Description

Technical Field

[0001] The present invention relates to a cleaning method for cleaning an object to be cleaned such as a metal processed product with a water replacement liquid, and a cleaning device capable of implementing such a cleaning method.

Background Art

[0002] In various industrial fields, processing oil is used when manufacturing metal processed products and the like. The processing oil is an oil processed according to various uses by refining and mixing a base oil and adding additives and the like. Further, the processing oil includes an oil-based processing oil and a water-soluble processing oil.

[0003] For example, since the oil-based processing oil dissolves in liquid hydrocarbons, metal processed products and the like processed with the oil-based processing oil (hereinafter also referred to as "objects to be cleaned") can be cleaned with appropriately managed liquid hydrocarbons, and even if the cleaning liquid is evaporated after cleaning, no water stain (watermark) occurs.

[0004] On the other hand, when a metal processed product or the like processed with a water-soluble processing oil is directly cleaned with liquid hydrocarbons as a cleaning liquid and then this cleaning liquid is evaporated, the moisture of the water-soluble processing oil adhering to the object to be cleaned generates water stains. Therefore, from the viewpoint of cleaning quality, it is necessary to remove the moisture adhering to the surface of the object to be cleaned and then proceed to the subsequent process with the cleaning liquid.

[0005] In addition, in the manufacturing and processing process of metal processed parts, various water cleaning treatments are also performed with an aqueous cleaning agent for the purpose of removing dirt or the like, or a cleaning agent obtained by emulsifying a cleaning liquid containing a surfactant and water in a hydrocarbon-based solvent. If these cleaning liquids containing water or water-soluble substances are evaporated as they are, water stains will similarly occur. Therefore, these also must be removed after cleaning.

[0006] For this reason, it has been proposed to remove moisture from the surface of the object to be cleaned by using a water displacement solution (water-removing cleaning solution). The water displacement solution is a cleaning solution that has a water displacement effect and does not show miscibility with water. In this cleaning method using a water displacement solution, the object to be cleaned, which has water adhering to its surface, is immersed in the water displacement solution, and after water displacement occurs during this immersion step, the water displacement solution is dried. By performing cleaning with such a water displacement solution, it is possible to prevent water stains from occurring on the surface of the object to be cleaned.

[0007] Regarding cleaning methods using water displacement solutions, for example, Patent Document 1 (Japanese Patent Application Publication No. 2020-195964) proposes a cleaning method that includes: a cleaning step of immersing an object to be cleaned in a cleaning solution containing a hydrocarbon solvent, a surfactant, and water to emulsify and separate water-soluble dirt from the object to be cleaned; a rinsing step of immersing the cleaned object in a hydrocarbon solvent rinsing solution and rinsing it under ultrasonic irradiation; a drying step of drying the rinsed object; and a regeneration step of separating water from the degraded rinsing solution used in the rinsing step to regenerate the rinsing solution. [Patent Document 1] Japanese Patent Publication No. 2020-195964 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the cleaning process for dewatering described in Patent Document 1, the object to be cleaned is immersed in a cleaning solution (water displacement solution) to separate water and water-soluble dirt from the object. In order to clean the object by immersion, it is necessary to prepare an immersion tank that has space to accommodate the entire volume of the object to be cleaned and the structures supporting it, and the amount of water displacement solution must also be large enough to fill the space. In other words, the water displacement process using water displacement solution has the problem of increasing the size of the entire cleaning device and requiring the preparation of a large amount of water displacement solution, which increases the installation area and operating costs of the cleaning device. [Means for solving the problem]

[0009] To solve the above problems, the cleaning method according to the present invention is characterized by comprising: a water displacement liquid injection step of injecting a water displacement liquid onto an object to be cleaned in a cleaning tank; a cleaning liquid cleaning step of cleaning the object to be cleaned with a cleaning liquid in the cleaning tank after the water displacement liquid injection step; and a cleaning liquid vaporization step of vaporizing the cleaning liquid.

[0010] Furthermore, the cleaning method according to the present invention is characterized by having a water removal step in which water is removed from the water displacement liquid used in the cleaning tank.

[0011] Furthermore, the cleaning method according to the present invention is characterized in that the cleaning step is performed by immersing the object to be cleaned in a cleaning solution.

[0012] Furthermore, the cleaning method according to the present invention is characterized in that the cleaning liquid cleaning step is performed by spraying a cleaning liquid onto the object to be cleaned.

[0013] Furthermore, the cleaning method according to the present invention is characterized in that the cleaning liquid vaporization step involves introducing the vapor of the cleaning liquid into the cleaning tank and then reducing the pressure inside the cleaning tank.

[0014] Furthermore, the cleaning method according to the present invention is characterized in that, in the cleaning liquid vaporization step, the cleaning liquid adhering to the object to be cleaned is vaporized by reducing the pressure inside the cleaning tank.

[0015] Furthermore, the cleaning method according to the present invention is characterized in that the cleaning solution contains a liquid hydrocarbon, and the liquid hydrocarbon is a mixture of two or more of the following: normal paraffin, isoparaffin, naphthene, or normal paraffin, isoparaffin, and naphthene.

[0016] Furthermore, the cleaning method according to the present invention is characterized in that the water displacement solution is the cleaning solution to which a surfactant has been added.

[0017] Furthermore, the cleaning apparatus according to the present invention is characterized by comprising: a cleaning tank in which an object to be cleaned is contained and the object to be cleaned is cleaned; a water displacement liquid introduction pipe for introducing a water displacement liquid into the cleaning tank; and a spray nozzle for spraying the water displacement liquid introduced by the water displacement liquid introduction pipe onto the object to be cleaned.

[0018] Furthermore, the cleaning apparatus according to the present invention is characterized by having a drain section for discharging the water displacement liquid used in the cleaning tank to the outside of the cleaning tank, and a dewatering tank for storing the water displacement liquid discharged from the drain section and for removing water from the stored water displacement liquid.

[0019] Furthermore, the cleaning apparatus according to the present invention is characterized by having a vacuum pump that reduces the pressure inside the dewatering tank, and by operating the vacuum pump to vaporize the water from the stored water displacement liquid and remove water.

[0020] Furthermore, the washing apparatus according to the present invention is characterized by having an introduction pipe for a gas with a humidity of less than 100% in the dewatering tank, and removing water by vaporizing the water from the stored water displacement liquid by bringing the gas into contact with the water displacement liquid.

[0021] Furthermore, the washing apparatus according to the present invention is characterized in that it removes water by separating it from the stored water displacement liquid in the dewatering tank by utilizing the difference in specific gravity between the water displacement liquid and water.

[0022] Furthermore, the cleaning apparatus according to the present invention is characterized by having a vacuum pump that reduces the pressure inside the cleaning tank, and by operating the vacuum pump, water is vaporized from the water displacement liquid used in the cleaning tank and removed.

[0023] Furthermore, the cleaning apparatus according to the present invention has a discharge section for discharging the water-displacement liquid used in the cleaning tank to a centrifugal separator, and is characterized in that it removes water by separating it from the water-displacement liquid using the difference in specific gravity between the water-displacement liquid and water in the centrifugal separator.

[0024] Further, the cleaning device according to the present invention has a cleaning liquid introduction pipe for introducing a cleaning liquid into the cleaning tank, and is characterized in that the object to be cleaned is immersed in the cleaning liquid introduced through the cleaning liquid introduction pipe.

[0025] Further, the cleaning device according to the present invention has a vibrator disposed in the cleaning tank, and is characterized in that vibration is applied to the cleaning liquid by operating the vibrator.

[0026] Further, the cleaning device according to the present invention is characterized by having a cleaning liquid vapor introduction pipe for introducing vapor of the cleaning liquid into the cleaning tank.

[0027] Further, the cleaning device according to the present invention has a cleaning liquid introduction pipe for introducing a cleaning liquid into the cleaning tank, and is characterized in that the cleaning liquid introduced through the cleaning liquid introduction pipe is sprayed onto the object to be cleaned by the injection nozzle.

[0028] Further, the cleaning device according to the present invention has a vacuum pump for decompressing the inside of the cleaning tank, and is characterized in that the cleaning liquid adhering to the object to be cleaned is vaporized by operating the vacuum pump.

Advantages of the Invention

[0029] The cleaning method according to the present invention includes a water replacement liquid injection step of injecting a water replacement liquid onto the object to be cleaned in a cleaning tank, and a cleaning liquid immersion step of immersing the object to be cleaned in the cleaning liquid in the cleaning tank after the water replacement liquid injection step. Therefore, according to the cleaning method of the present invention, the water replacement liquid injection step and the cleaning liquid immersion step can be carried out in the same cleaning tank, and the enlargement of the cleaning device and the installation area can be suppressed. Further, according to the cleaning method of the present invention, the water replacement liquid is brought into contact with the object to be cleaned by spraying, so there is no need to immerse the object to be cleaned in the water replacement liquid, the required amount of the water replacement liquid is reduced, and the operation cost can be reduced.

[0030] Furthermore, the cleaning apparatus according to the present invention has a spray nozzle that sprays the water displacement liquid introduced in the water displacement liquid introduction pipe onto the object to be cleaned, and a drain section that discharges the water displacement liquid used in the cleaning tank to the outside of the cleaning tank. With such a cleaning apparatus according to the present invention, the water displacement liquid used in the cleaning tank is discharged from the drain section, and the cleaning tank can be used for cleaning with cleaning liquids other than the water displacement liquid, thus reducing the size and installation area of ​​the cleaning apparatus. In addition, with the cleaning apparatus according to the present invention, since the water displacement liquid is brought into contact with the object to be cleaned by spraying, there is no need to immerse the object to be cleaned in the water displacement liquid, the amount of water displacement liquid required is reduced, and operating costs can be reduced. [Brief explanation of the drawing]

[0031] [Figure 1] This figure schematically shows an overview of the cleaning apparatus 1 according to the first embodiment of the present invention. [Figure 2] This figure illustrates the cleaning process using the cleaning apparatus 1 according to the first embodiment of the present invention. [Figure 3] This figure illustrates the cleaning process using the cleaning apparatus 1 according to the first embodiment of the present invention. [Figure 4] This figure illustrates the cleaning process using the cleaning apparatus 1 according to the first embodiment of the present invention. [Figure 5] This figure schematically shows an overview of the cleaning apparatus 1 according to the second embodiment of the present invention. [Figure 6] This figure schematically shows an overview of the cleaning apparatus 1 according to the third embodiment of the present invention. [Figure 7] This figure schematically shows an overview of the cleaning apparatus 1 according to the fourth embodiment of the present invention. [Figure 8] This figure schematically shows an overview of the cleaning apparatus 1 according to the fifth embodiment of the present invention. [Modes for carrying out the invention]

[0032] The present invention will now be described in detail. The inventors of the present invention discovered that, in a water-displacing liquid having sufficient water-displacing performance, wetting occurs and a water-displacing phenomenon occurs on the surface of the object to be cleaned simply by bringing the water-displacing liquid into contact with the object to be cleaned, which is contaminated with water or water-soluble dirt, without immersing the object to be cleaned in the water-displacing liquid as in the conventional method. In other words, they found that liquid contact by immersion is not necessarily required to cause a water-displacing phenomenon on the surface of the object to be cleaned by a water-displacing liquid, and that a water-displacing phenomenon can be caused by supplying the water-displacing liquid to the surface of the object to be cleaned without any gaps. The cleaning method and cleaning apparatus according to the present invention, which will be described below, were obtained based on these findings.

[0033] The cleaning method and cleaning apparatus according to the present invention relate to a technique for removing water from the surface of metal workpieces, etc. ("workpieces to be cleaned") that have been processed with water-soluble processing oil or washed with water, by performing water-displacing cleaning with a water-displacing liquid, and further cleaning the workpieces with a cleaning liquid such as a liquid hydrocarbon. Here, the water and water-soluble dirt targeted by the present invention, as well as the cleaning liquid and water-displacing liquid used, will be described.

[0034] The water and water-soluble contaminants targeted by this invention include those in which water is in a continuous phase and those in which water is in a dispersed phase. For example, in water-soluble cutting oils of types A1 to A3 as defined in JIS K2241, water-based cleaning agents, or their rinsing water, water is mainly in a continuous phase. On the other hand, in cleaning agents that emulsify a cleaning solution containing a surfactant and water in a hydrocarbon solvent, water is mainly in a dispersed phase.

[0035] The cleaning solution used in the present invention contains a liquid hydrocarbon (liquid hydrocarbon solvent), and this liquid hydrocarbon is normal paraffin, isoparaffin, naphthene, or a mixture of two or more of normal paraffin, isoparaffin, and naphthene, wherein the isoparaffin, normal paraffin, and naphthene may have 8 to 20 carbon atoms, preferably 9 to 15 carbon atoms, and more preferably 10 to 13 carbon atoms.

[0036] In the present invention, the hydrocarbon solvents used in the water displacement solution or the cleaning solution may include, in addition to the normal paraffinic solvents and isoparaffinic solvents mentioned above, other liquid hydrocarbon solvents. For example, one solvent selected from the group consisting of normal paraffinic solvents, isoparaffinic solvents, naphthenic solvents, and aromatic solvents, or a mixture of two or more solvents selected from these groups, may be used. Furthermore, even if the cleaning solution contains organic solvents such as alcohol or glycol ether, there is no particular problem as long as it does not impair the cleaning performance.

[0037] As described above, a coarse cleaning solution and a rinsing solution are used as cleaning solutions. The difference between the coarse cleaning solution and the rinsing solution is that the latter cleaning solution contains fewer impurities and is clearer.

[0038] The water-displacing solution used in the present invention can be a hydrocarbon solvent to which a surfactant has been added, as described above. The surfactant that can be used in the water-displacing solution is not particularly limited, but nonionic or anionic surfactants can be used individually or in combination.

[0039] The concentration of the surfactant is not particularly limited, but it is between 0.01% by weight and 10% by weight relative to the cleaning solution, and preferably between 0.1% by weight and less than 4% by weight. If the content is less than 0.01% by weight, a sufficient water displacement effect cannot be obtained, and even if the content exceeds 10% by weight, no improvement in the water displacement effect can be expected. In particular, when the target water or water-soluble dirt is a continuous phase of water, more surfactant is required to displace the water adhering from the surface of the object to be cleaned, and it is desirable that the content be 0.1% by weight or more. When the target water or water-soluble dirt is a dispersed phase, the amount of surfactant required to displace the water adhering from the surface of the object to be cleaned can be reduced.

[0040] Among the surfactants that can be used in water displacement solutions, nonionic surfactants include ester types in which polyhydric alcohols and fatty acids are ester-bonded; ether types obtained by adding alkylene oxides such as ethylene oxide, propylene oxide, or butylene oxide to hydroxyl group-containing raw materials such as higher alcohols and alkylphenols; ester-ether types obtained by adding the above alkylene oxides to esters composed of polyhydric alcohols and fatty acids; fatty acid amine types composed of alkylamines and fatty acids; and fatty acid ethanolamide types composed of alkylethanolamides and fatty acids. Anionic surfactants include petroleum sulfonates, sulfonate types such as belladonna oil, and sulfate ester salt types.

[0041] In the cleaning method and cleaning apparatus according to the present invention, the water displacement liquid described above is sprayed onto the object to be cleaned to bring it into contact with it, thereby causing a water displacement phenomenon on the surface of the object to be cleaned. Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a schematic diagram showing an overview of a cleaning apparatus 1 according to the first embodiment of the present invention. The cleaning apparatus 1 can be suitably used to carry out the cleaning method according to the present invention.

[0042] The cleaning apparatus 1 according to the present invention has a cleaning tank 10. A structure (not shown) that supports the metal workpiece W places the metal workpiece W, which is the object to be cleaned, into the cleaning tank 10, and the object to be cleaned is cleaned. In the following description, a metal workpiece W will be used as an example of the object to be cleaned, but the cleaning method and cleaning apparatus 1 according to the present invention can also be applied to cleaning processed products of other materials, such as glass products and plastic products.

[0043] As described above, in cleaning using the cleaning apparatus 1 according to the present invention, in order to suppress water stains on the metal workpiece W, moisture adhering to the surface of the metal workpiece W is removed by a water displacement liquid in a step prior to cleaning with the cleaning liquid. At this time, the water displacement liquid is sprayed from the spray nozzle 11 and brought into contact with the metal workpiece W. In describing the cleaning apparatus 1 according to the present invention, the expression "spraying" the water displacement liquid from the spray nozzle 11 will be used, but in this specification, words such as "spray," "shower," "aerosol," and "jet" are considered to be synonymous with "spray."

[0044] The water displacement liquid tank 20 is a tank that stores the water displacement liquid to be sprayed from the spray nozzle 11. The water displacement liquid introduction pipe 52 is a pipe that transfers the water displacement liquid from the water displacement liquid tank 20 into the cleaning tank 10. A pump 81 is provided in the water displacement liquid introduction pipe 52, and when the pump 81 operates, the water displacement liquid is transferred into the cleaning tank 10. The water displacement liquid transferred in the water displacement liquid introduction pipe 52 is sprayed from the spray nozzle 11 onto the object to be cleaned in the cleaning tank 10. The spray nozzle 11 may have a fixed outlet and spray the water displacement liquid in only one direction, or it may have a movable outlet and the direction in which the water displacement liquid is sprayed can be changed. In addition, there may be a means to change the position of the object to be cleaned while the water displacement liquid is being sprayed from the spray nozzle 11.

[0045] The water displacement liquid used in the washing tank 10 is discharged to the outside of the washing tank 10 from the drain section 13. The water displacement liquid discharged from the washing tank 10 flows down into the piping 60. The piping 60 is equipped with a valve 41 for opening and closing the flow path and a three-way valve 91 for selectively switching between flow path (a) and flow path (b). Flow path (a) is a flow path connecting the washing tank 10 and the dewatering tank 40, and flow path (b) is a flow path connecting the washing tank 10 and the washing liquid tank 30 (more specifically, the crude washing liquid tank 33 or the rinse liquid tank 34) via the washing liquid recovery piping 63.

[0046] The dewatering tank 40 is a tank that receives the water displacement liquid used in the washing tank 10. The purpose of providing such a dewatering tank 40 is to remove water from the water displacement liquid that contains water and is used in the washing tank 10. Methods such as decantation, use of adsorbents, and distillation can be appropriately selected to remove water from the water displacement liquid, but in this embodiment, water is removed from the water displacement liquid by vaporization dewatering. For this purpose, the dewatering tank 40 is provided with a pipe 59 that connects the dewatering tank 40 to the outside of the washing device, and a vacuum pump 74 is further provided in this pipe 59. When the vacuum pump 74 operates, the pressure inside the washing tank 10 is reduced to below the vapor pressure of water, causing water to boil and be removed from the water displacement liquid inside the washing tank 10.

[0047] In addition to the vaporization dehydration method described above, the removal of water from the water displacement liquid in the dewatering tank 40 can also be achieved by providing a gas introduction pipe (not shown) in the dewatering tank 40, introducing a gas with a humidity of less than 100% through this gas introduction pipe, and bringing the gas into contact with the water displacement liquid, thereby vaporizing the water from the water displacement liquid stored in the dewatering tank 40 and removing the water.

[0048] Furthermore, the removal of water from the water displacement liquid in the dewatering tank 40 can also be done by utilizing the difference in specific gravity between the water displacement liquid and water within the dewatering tank 40 to separate and remove the water from the stored water displacement liquid.

[0049] The water displacement liquid recovery piping 61 is a pipe that connects the dewatering tank 40 and the water displacement liquid tank 20, and is used to recover the water displacement liquid from the dewatering tank 40 into the water displacement liquid tank 20. A pump 82 is provided in the water displacement liquid recovery piping 61, and when the pump 82 operates, the water-displaced water displacement liquid from the dewatering tank 40 is transferred to the water displacement liquid tank 20.

[0050] The water displacement liquid tank 20 is equipped with a pipe 57 connecting the water displacement liquid tank 20 to the outside of the washing device, and a vacuum pump 72 is also installed in this pipe 57. The vacuum pump 72 allows the water displacement liquid tank 20 to be depressurized when it operates. The water displacement liquid tank 20 is also equipped with a temperature control coil 37. Steam, heat transfer oil, etc. are flowed through the temperature control coil 37 to heat the water displacement liquid in the water displacement liquid tank 20. In addition, water can be removed from the water displacement liquid in the water displacement tank 20, as in the dewatering tank 40.

[0051] The cleaning solution tank 30 is a tank for storing cleaning solution used to clean the object to be cleaned after water displacement with the water displacement solution. In this embodiment, the cleaning of the object to be cleaned will be explained based on an example in which a two-stage cleaning is performed, consisting of cleaning with a coarse cleaning solution and then cleaning with a rinsing solution. However, it is also possible to perform a third or more cleaning stage with a clearer rinsing solution.

[0052] The cleaning fluid tank 30 contains two tanks: a crude cleaning fluid tank 33 and a rinse fluid tank 34. The cleaning fluid introduction piping 53 is a pipe that transfers the respective cleaning fluids from the crude cleaning fluid tank 33 and the rinse fluid tank 34 into the cleaning tank 10. A valve 43 for opening and closing the flow path is provided in the cleaning fluid introduction piping 53 that is directly connected to the crude cleaning fluid tank 33, and a valve 44 for opening and closing the flow path is provided in the cleaning fluid introduction piping 53 that is directly connected to the rinse fluid tank 34.

[0053] The cleaning fluid introduction pipe 53 is equipped with a three-way valve 93 that selectively switches between flow path (c) and flow path (d). Flow path (c) is a flow path connecting the cleaning tank 10 and the crude cleaning fluid tank 33, and flow path (d) is a flow path connecting the cleaning tank 10 and the rinse fluid tank 34. A pump 83 is provided in the cleaning fluid introduction pipe 53, and when the pump 83 operates, the crude cleaning fluid or rinse fluid is transferred into the cleaning tank 10.

[0054] A three-way valve 94 is provided in the cleaning fluid recovery piping 63 to selectively switch between flow path (e) and flow path (f). Flow path (e) is a flow path connecting the cleaning tank 10 and the crude cleaning fluid tank 33, and flow path (f) is a flow path connecting the cleaning tank 10 and the rinse fluid tank 34. A pump 84 is provided in the cleaning fluid recovery piping 63, and when the pump 84 operates, either the crude cleaning fluid or the rinse fluid can be transferred into the cleaning tank 10.

[0055] The cleaning fluid tank 30 is provided with a pipe 58 connecting the cleaning fluid tank 30 to the outside of the cleaning device, and a vacuum pump 73 is also provided in this pipe 58. The vacuum pump 73 operates to reduce the pressure inside the cleaning fluid tank 30.

[0056] A temperature control coil 38 is provided in the crude cleaning solution tank 33. Steam, heat transfer oil, etc. are circulated through the temperature control coil 38 to heat the crude cleaning solution in the crude cleaning solution tank 33. A temperature control coil 39 is also provided in the rinsing solution tank 34. Steam, heat transfer oil, etc. are circulated through the temperature control coil 39 to heat the rinsing solution in the rinsing solution tank 34.

[0057] The distillation regeneration tank 5 is provided to remove dirt and surfactants contained in the cleaning solution. The cleaning solution transferred to the distillation regeneration tank 5 comes from the crude cleaning solution tank 33, and for this reason, a pipe 65 is provided to form a flow path connecting the crude cleaning solution tank 33 and the distillation regeneration tank 5. A pump 85 is provided in the pipe 65, and when the pump 85 operates, the crude cleaning solution can be transferred from the crude cleaning solution tank 33 to the distillation regeneration tank.

[0058] In the distillation regeneration tank 5, the crude cleaning solution is heated and vaporized into steam, which is then transported through piping 66. Piping 66 is provided with a three-way valve 95 that selectively switches between flow path (g) and flow path (h). Flow path (g) is a flow path formed by the cleaning solution steam introduction piping 55 that connects the distillation regeneration tank 5 and the cleaning tank 10, while flow path (h) is a flow path that connects the distillation regeneration tank 5 and the rinse solution tank 34 in the cleaning solution tank 30 via piping 66.

[0059] A cooler 7 is installed in the piping 66 downstream of the three-way valve 95, and the vapor of the cleaning solution vaporized in the distillation regeneration tank 5 is liquefied in the cooler 7. The cleaning solution liquefied in the cooler 7 is transferred to the rinse solution tank 34 as a clarified cleaning solution. The liquid level in the rinse solution tank 34 is kept higher than the liquid level in the crude cleaning solution tank 33, and the cleaning solution that overflows from the rinse solution tank 34 flows into the crude cleaning solution tank 33. This makes it possible to suppress the increase in the fouling concentration of the crude cleaning solution in the crude cleaning solution tank 33.

[0060] If flow path (g) is selected by the three-way valve 95, the cleaning liquid vaporized in the distillation regeneration tank 5 is introduced into the cleaning tank 10 via the cleaning liquid vapor introduction pipe 55, and used for steam cleaning of the object to be cleaned.

[0061] The cleaning tank 10 is provided with a pipe 56 connecting the cleaning tank 10 to the outside of the cleaning device, and a vacuum pump 71 is installed in this pipe 56. The vacuum pump 71 allows the pressure inside the cleaning tank 10 to be reduced by operation. The cleaning tank 10 is also provided with a vibrator 15, and by operating the vibrator 15, vibrations can be applied to the object to be cleaned, which is immersed in the cleaning solution.

[0062] The cleaning device 1 according to the first embodiment of the present invention is basically configured as described above, but a means for removing dirt, such as a filter, may be appropriately provided in the illustrated piping of the cleaning device 1. Alternatively, such a means for removing dirt may be provided in new piping not shown.

[0063] Next, a cleaning method using the cleaning apparatus 1 according to the first embodiment configured as described above will be explained. The cleaning method according to this embodiment described below is just one example, and the cleaning method according to the present invention is not limited to the following description.

[0064] Furthermore, the cleaning method described herein may be performed manually or automatically. To automatically execute the cleaning method according to the present invention, a controller such as a microcomputer can be used, for example.

[0065] In this case, a controller such as a microcomputer, timing devices, sensors to measure the vacuum level in each tank, sensors to measure the liquid flow rate, sensors to measure the liquid level in each tank, and sensors to measure the cleanliness of the water displacement liquid or cleaning liquid are provided, and the measurement information from these sensors is input to the controller. The controller receives the measurement information from these sensors and input from the timing devices, makes decisions according to a predetermined algorithm, and outputs control commands such as opening and closing valves, switching flow paths in three-way valves, and turning vacuum pumps on and off.

[0066] Figure 2 schematically shows the water displacement liquid injection process in the cleaning apparatus 1 according to the first embodiment of the present invention. In the cleaning method according to the present invention, the metal workpieces W (workpieces to be cleaned) are, for example, processed with water-soluble processing oil, and these workpieces are placed in the cleaning tank 10 by being supported by a support structure (not shown) or the like.

[0067] In preparation for the water displacement liquid injection process in the washing device 1, valve 41 is closed to prevent the water displacement liquid used in the washing tank 10 from flowing down into the dewatering tank 40.

[0068] Valve 51 is opened. Since a flammable water displacement solution is used, safety is ensured by reducing the pressure inside the cleaning tank 10 using a vacuum pump 71. Depending on the flash point of the water displacement solution, the pressure inside the cleaning tank 10 is, for example, between 0.1 atmospheres and below atmospheric pressure. If water evaporates from the surface of the object to be cleaned, it can cause water stains, but at room temperature, water adhering to the object to be cleaned will not boil at a pressure of approximately 0.1 atmospheres and below atmospheric pressure, so it is preferable to maintain the pressure inside the cleaning tank 10 at this level. Once the pressure reduction inside the cleaning tank 10 is complete, valve 51 is closed.

[0069] Preferably, the water displacement liquid in the water displacement liquid tank 20 is kept at a temperature of approximately 40°C or higher than room temperature by the temperature control coil 37. The pump 81 is operated to spray the water displacement liquid onto the object to be cleaned using the spray nozzle 11. The sprayed water displacement liquid causes a water displacement phenomenon on the surface of the object to be cleaned, thereby removing moisture from the surface of the object to be cleaned.

[0070] The removed water, along with the sprayed water displacement liquid, falls to the bottom of the washing tank 10. Because the valve 41 is closed, the water removed from the surface of the object being washed and the used water displacement liquid do not flow down into the dewatering tank 40.

[0071] The advantage of contacting the object to be cleaned by spraying the water displacement solution rather than by immersion is that only the amount of water displacement solution to be sprayed needs to be prepared, thus reducing the operating cost of the cleaning device 1. Furthermore, even if the metal processed product W has a blind hole, the water displacement solution can still come into contact with the inside of the blind hole as it diffuses through the spraying.

[0072] Furthermore, according to the cleaning method of the present invention, the water displacement liquid injection step and the cleaning liquid immersion step (described in detail later) can be performed in the same cleaning tank 10, thereby reducing the size and installation area of ​​the cleaning equipment.

[0073] The water removed from the surface of the object to be cleaned and the water displacement liquid that are falling to the bottom of the washing tank 10 are directed to the dewatering tank 40 by selecting flow path (a) with the three-way valve 91 and opening valve 41, where they are stored.

[0074] Once the entire volume of water and water displacement solution in the washing tank 10 has flowed down into the dewatering tank 40, the valve 41 is closed. As a result, the dewatering tank 40 and the washing tank 10 become independent compartments, allowing the dewatering tank 40 to perform a process of removing water from the water displacement solution (hereinafter also referred to as the water displacement solution) containing the water removed from the object to be washed, while the washing tank 10 can perform a rough washing process (washing solution immersion process) using a rough washing solution. In this specification, the term "washing solution washing process" is defined to refer to a process that includes either a rough washing process using a rough washing solution or a rinsing process using a rinsing solution.

[0075] To remove water from the water displacement liquid stored in the dewatering tank 40, the vacuum pump 74 is operated to reduce the pressure inside the dewatering tank 40 to below the vapor pressure of water (for example, 40 Torr). As a result, the water in the water displacement liquid is exhausted as gas to the outside of the washing device. Once sufficient water has been removed from the water displacement liquid, the pump 82 is operated to transfer the water displacement liquid in the dewatering tank 40 to the water displacement liquid tank 20. The process of removing water from the water displacement liquid in the dewatering tank 40, etc., is called the "water removal process".

[0076] Figure 3 schematically shows the cleaning liquid immersion process in the cleaning apparatus 1 according to the first embodiment of the present invention. In Figure 3, the flow path (c) is selected in the three-way valve 93, the valve 43 is opened, and the pump 83 is operated to transfer the crude cleaning liquid in the crude cleaning liquid tank 33 to the cleaning tank 10 through the cleaning liquid introduction pipe 53, and the entire object to be cleaned is immersed in the crude cleaning liquid to perform cleaning with the cleaning liquid. The crude cleaning liquid stored in the crude cleaning liquid tank 33 and the rinsing liquid stored in the rinsing liquid tank 34 are kept at a temperature of approximately 40°C or higher than room temperature by the temperature control coil 38 and temperature control coil 39, respectively.

[0077] When the object to be cleaned is immersed in the coarse cleaning solution, it is preferable to apply physical force to the coarse cleaning solution during the cleaning process. In this embodiment, a transducer 15 such as an ultrasonic oscillator is operated to vibrate the cleaning tank 10, thereby applying vibration to the coarse cleaning solution as well, in order to improve the cleaning efficiency of the object to be cleaned.

[0078] The method of applying physical force to the crude cleaning solution to improve the cleaning efficiency of the object to be cleaned is not limited to the method of applying vibration with the vibrator 15. For example, the crude cleaning solution may be stirred with an agitator, a jet may be generated in the cleaning tank 10 with a pump, or a bubbling method such as introducing air or nitrogen gas from below the cleaning tank 10 may be used. Each of the listed methods can be used individually or in combination.

[0079] Once the cleaning of the object to be cleaned with the coarse cleaning solution in the cleaning tank 10 is complete, the coarse cleaning solution in the cleaning tank 10 is collected in the coarse cleaning solution tank 33. To do this, the three-way valve 91 is set to flow path (b), valve 41 is opened, and the pump 84 is operated to transfer the coarse cleaning solution in the cleaning tank 10 through the cleaning solution collection pipe 63.

[0080] After the cleaning process with the coarse cleaning solution as described above, further cleaning is performed using the rinsing solution stored in the rinsing solution tank 34. The cleaning of the object with the rinsing solution can be carried out in almost the same procedure as the cleaning with the coarse cleaning solution. However, in the cleaning with the rinsing solution, the valve operations are as follows: in the step of introducing the rinsing solution into the cleaning tank 10, the three-way valve 93 is set to flow path (d), valve 44 is opened, and pump 83 is operated. After cleaning the object with the rinsing solution, in the step of recovering the rinsing solution from the cleaning tank 10, the three-way valve 91 is set to flow path (b), the three-way valve 94 is set to flow path (f), valve 41 is opened, and pump 84 is operated to transfer the rinsing solution in the cleaning tank 10 through the cleaning solution recovery pipe 63.

[0081] As described above, after the cleaning of the object to be cleaned by washing with a rough cleaning solution and a rinsing solution, the cleaning method according to this embodiment performs a steam cleaning step of the object to be cleaned. Figure 4 schematically shows the cleaning solution steam cleaning step in the cleaning apparatus 1 according to the first embodiment of the present invention.

[0082] First, we will explain the operation of the cleaning apparatus 1 during times other than the time period (P) in which the steam cleaning process for cleaning the object to be cleaned is performed (Q). During this time period (Q), the distillation regeneration tank 5 in the cleaning apparatus 1 functions to remove dirt contained in the crude cleaning liquid stored in the crude cleaning liquid tank 33. During time period (Q), the pump 85 is operated to transfer the crude cleaning liquid stored in the crude cleaning liquid tank 33 to the distillation regeneration tank 5.

[0083] In the distillation regeneration tank 5, the crude washing solution is vaporized, and this is then clarified in the cooler 7 before being transferred to the rinse solution tank 34. During time period (Q), the flow path (h) is selected in the three-way valve 95. In the cooler 7, the vapor of the washing solution vaporized in the distillation regeneration tank 5 is liquefied. The washing solution liquefied in the cooler 7 is then transferred to the rinse solution tank 34 as a clarified washing solution.

[0084] On the other hand, during the time period (P) in which the steam cleaning process for cleaning the object to be cleaned is performed, the flow path (g) is selected in the three-way valve 95, and the cleaning liquid vaporized in the distillation regeneration tank 5 is introduced into the cleaning tank 10 via the steam introduction pipe 55, which serves as the flow path, and is used for steam cleaning the object to be cleaned.

[0085] In this process, before introducing the cleaning solution vapor into the cleaning tank 10, valve 51 is opened and the inside of the cleaning tank 10 is depressurized by the vacuum pump 71. After the predetermined depressurization is complete, valve 51 is closed, and then the cleaning solution vaporized in the distillation regeneration tank 5 is introduced into the cleaning tank 10. This procedure is followed to prevent damage to the vacuum pump 71 by passing the cleaning solution vapor through it.

[0086] After the steam cleaning of the object to be cleaned is complete, the vacuum pump 71 is then operated to vaporize the droplets of cleaning solution adhering to the object, thereby completing the cleaning of the object. The cleaning solution that has been subjected to steam cleaning and liquefied is collected in the crude cleaning solution tank 33. In this specification, the process of vaporizing the droplets of cleaning solution adhering to the object to be cleaned will be referred to as the "cleaning solution vaporization process."

[0087] Furthermore, when steam cleaning the objects to be cleaned, it is preferable to have a large difference between the temperature of the objects to be cleaned when exposed to the steam of the cleaning solution and the temperature of the steam of the cleaning solution. Therefore, when cleaning by immersing the objects to be cleaned in the rinsing solution, the rinsing solution can be used to remove heat from the objects to be cleaned. For this purpose, both pump 83 and pump 84 may be operated throughout the immersion period to continuously supply fresh rinsing solution to the cleaning tank 10.

[0088] As described above, the cleaning method according to the present invention comprises a water displacement liquid spraying step in which a water displacement liquid is sprayed onto the object to be cleaned in a cleaning tank, and a cleaning liquid immersion step in which the object to be cleaned is immersed in the cleaning liquid in the cleaning tank after the water displacement liquid spraying step. Therefore, according to the cleaning method according to the present invention, the water displacement liquid spraying step and the cleaning liquid immersion step can be performed in the same cleaning tank, which can reduce the size and installation area of ​​the cleaning equipment. Furthermore, according to the cleaning method according to the present invention, since the water displacement liquid is brought into contact with the object to be cleaned by spraying, there is no need to immerse the object to be cleaned in the water displacement liquid, which reduces the amount of water displacement liquid required and makes it possible to reduce operating costs.

[0089] Furthermore, the cleaning device 1 according to the present invention has a spray nozzle 11 that sprays the water displacement liquid introduced in the water displacement liquid introduction pipe 52 onto the object to be cleaned, and a drain section 13 that discharges the water displacement liquid used in the cleaning tank 10 to the outside of the cleaning tank 10. With such a cleaning device 1 according to the present invention, the water displacement liquid used in the cleaning tank 10 is discharged from the drain section 13, and the cleaning tank 10 can be used for cleaning with cleaning liquids other than the water displacement liquid, thus reducing the size and installation area of ​​the cleaning device 1. In addition, with the cleaning device 1 according to the present invention, since the water displacement liquid is brought into contact with the object to be cleaned by spraying, there is no need to immerse the object to be cleaned in the water displacement liquid, the amount of water displacement liquid required is reduced, and operating costs can be reduced.

[0090] Next, other embodiments of the present invention will be described. Figure 5 is a schematic diagram showing an overview of the cleaning apparatus 1 according to the second embodiment of the present invention. In the cleaning apparatus 1 according to the second embodiment shown in Figure 5, components that are denoted by the same reference numerals as in the previous embodiment have the same configuration and function, so their description will be omitted.

[0091] The cleaning apparatus 1 according to the second embodiment differs from the cleaning apparatus 1 according to the first embodiment in that the dewatering tank 40 is omitted. In the cleaning apparatus 1 according to the first embodiment, the dewatering tank 40 was used to remove water from the water displacement liquid, but in the cleaning apparatus 1 according to the second embodiment, this water removal process is performed in the water displacement liquid tank 20. In order to remove water from the water displacement liquid in the water displacement liquid tank 20, the vacuum pump 72 is operated to reduce the pressure inside the water displacement liquid tank 20, thereby vaporizing the water from the water displacement liquid and removing it.

[0092] According to the cleaning apparatus 1 and cleaning method using the same as the cleaning apparatus 1 and cleaning method according to the first embodiment, it is possible to enjoy the same effects as the cleaning apparatus 1 and cleaning method according to the first embodiment, and the dewatering tank 40 is not required, making it possible to simplify the apparatus configuration.

[0093] In the second embodiment of the cleaning apparatus 1, the dewatering tank 40 is omitted and the process of removing water from the water displacement liquid is carried out in the water displacement liquid tank 20. However, such a water removal process can also be carried out in the cleaning tank 10. To do this, the valve 51 is opened and the vacuum pump 71 is operated to vaporize and remove water from the water displacement liquid used in the cleaning tank 10.

[0094] Next, other embodiments of the present invention will be described. Figure 6 is a schematic diagram showing an overview of the cleaning apparatus 1 according to the third embodiment of the present invention. In the cleaning apparatus 1 according to the third embodiment shown in Figure 6, components with the same reference numerals as those in the embodiments described so far have the same configuration and function, so their description will be omitted.

[0095] The cleaning method according to the first embodiment differs from the cleaning method according to the first embodiment in that the cleaning with the crude cleaning solution and the rinsing solution is performed in the same way as with the water displacement solution, that is, by spraying the crude cleaning solution and the rinsing solution onto the object to be cleaned.

[0096] For this purpose, a cleaning fluid introduction pipe 53, as shown in Figure 6, is used so that the coarse cleaning fluid and rinsing fluid can be sprayed from the spray nozzle 11. In the illustrated configuration, the spray nozzle 11 is shared by both the water displacement fluid and the cleaning fluid, but different spray nozzles can be used for each. Furthermore, a valve that opens and closes to prevent the inflow of cleaning fluid can be provided in the water displacement fluid introduction pipe 52, and a valve that opens and closes to prevent the inflow of water displacement fluid can also be provided in the cleaning fluid introduction pipe 53.

[0097] In the cleaning method according to the third embodiment, a water displacement liquid spraying step is performed in which a water displacement liquid is sprayed onto the object to be cleaned using a spray nozzle 11. Subsequently, a rough cleaning liquid spraying step is performed in which a rough cleaning liquid stored in a rough cleaning liquid tank 33 is sprayed onto the object to be cleaned in the cleaning tank 10. Further, a rinsing liquid spraying step is performed in which a rinsing liquid stored in a rinsing liquid tank 34 is sprayed. The "cleaning liquid spraying step" includes both the "rough cleaning liquid spraying step" and the "rinsing liquid spraying step".

[0098] In the cleaning apparatus 1 and cleaning method according to the third embodiment, the coarse cleaning solution and the rinsing solution are brought into contact with the object to be cleaned by spraying, similar to the water displacement solution. Therefore, the amount of coarse cleaning solution and rinsing solution required is not sufficient to immerse the object to be cleaned. Accordingly, according to this embodiment, the required amounts of coarse cleaning solution and rinsing solution are reduced, making it possible to reduce operating costs.

[0099] Furthermore, while the cleaning method according to the first embodiment involved steam cleaning using the vapor of the cleaning solution, the cleaning method according to the third embodiment does not involve steam cleaning. Therefore, in the cleaning apparatus 1 according to the third embodiment, the cleaning solution is guided to the cooler 7 through the pipe 66 vaporized by the distillation regeneration tank 5.

[0100] Furthermore, in the cleaning apparatus 1 according to the third embodiment, since steam cleaning is not performed, the temperature of the crude cleaning solution and the rinsing solution is set higher than in the first embodiment. Specifically, the crude cleaning solution stored in the crude cleaning solution tank 33 and the rinsing solution stored in the rinsing solution tank 34 are maintained at a temperature of approximately 80°C by the respective temperature control coils 38 and 39.

[0101] In the cleaning method according to the third embodiment, a rinsing liquid spraying step is performed in which rinsing liquid is sprayed onto the object to be cleaned in the cleaning tank 10. After cleaning with the rinsing liquid is completed, the vacuum pump 71 is then operated to vaporize the cleaning liquid (rinsing liquid) adhering to the object to be cleaned, thereby completing the cleaning of the object.

[0102] According to the cleaning apparatus 1 and cleaning method of the third embodiment described above, it is possible to enjoy the same effects as in the first embodiment, and furthermore, the required amounts of crude cleaning solution and rinsing solution can be reduced, making it possible to further reduce the operating costs of the apparatus.

[0103] Next, other embodiments of the present invention will be described. Figure 7 is a schematic diagram showing an overview of the cleaning apparatus 1 according to the fourth embodiment of the present invention. In the cleaning apparatus 1 according to the fourth embodiment shown in Figure 7, components that are denoted by the same reference numerals as in the previous embodiments have the same configuration and function, so their description will be omitted.

[0104] The washing apparatus 1 according to the fourth embodiment, like the washing apparatus 1 according to the second embodiment, omits the dewatering tank 40 from the washing apparatus 1 according to the first embodiment. In the washing apparatus 1 according to the fourth embodiment, as with the washing apparatus 1 according to the second embodiment, the process of removing water from the water displacement liquid is carried out in the water displacement liquid tank 20, but the method of removing water from the water displacement liquid differs from that of the washing apparatus 1 according to the second embodiment. The configuration for this is described below.

[0105] In the cleaning apparatus 1 according to the fourth embodiment, the water displacement liquid tank 20 has a water discharge section 123 at its lower part. The water displacement liquid tank 20 is connected to a water storage tank 130 via a pipe 135 from this water discharge section 123. A valve 142 that allows the flow path to be opened and closed is provided in the pipe 135.

[0106] Furthermore, in the cleaning apparatus 1 according to the fourth embodiment, the water displacement liquid tank 20 is provided with a pipe 57 connecting the water displacement liquid tank 20 to the outside of the cleaning apparatus. On the other hand, a vacuum pump 72 is not provided in this pipe 57.

[0107] In the present invention, the method for removing water in the water removal step, which aims to discharge water from the water-displacement liquid after use, is not particularly limited, but can be divided into two categories: a method for separating and discharging water in a liquid state, and a method for separating and discharging water as water vapor. Furthermore, the former method of separating and discharging water in a liquid state can be described as separation by specific gravity difference, which utilizes the difference in specific gravity between the water-displacement liquid and water, and adsorption separation, which utilizes the difference in adsorption properties between the water-displacement liquid and water.

[0108] Methods using specific gravity difference separation utilize the difference in specific gravity between the hydrocarbon solvent, which is the main component of the washing solution or water displacement solution, and water. These methods can be used individually or in combination with other methods such as static separation or centrifugal separation. Static separation does not require power, and centrifugal separation requires a small amount of liquid in the apparatus. At this time, droplet coarsening can be promoted as needed by adding voltage, separation plates, coalescers, and coagulants.

[0109] In the cleaning apparatus 1 according to the fourth embodiment, the method of static separation is employed over the other method of centrifugal separation. Specifically, in the water displacement liquid tank 20, the water separated by specific gravity at the bottom is removed from the water displacement liquid by opening and closing the valve 142 as appropriate, and flowing down through the piping 135 to the water storage tank 130.

[0110] When employing a method using centrifugal separation, the water displacement liquid can be discharged from the discharge port of the water displacement liquid tank 20 to a centrifugal separator (not shown), and this centrifugal separator can be configured to remove water by separating it from the water displacement liquid using the difference in specific gravity between the water displacement liquid and water within the water displacement liquid.

[0111] While there are no particular limitations on the type of centrifugal separator used, decanter, basket, disc, and cyclone types can be used individually or in combination. Among these, the cyclone type has a simple structure, no moving parts, and is easy to miniaturize, while the disc type easily generates high centrifugal force, making it easy to stably remove fine water droplets.

[0112] When removing water from a water displacement solution using physical adsorption separation that utilizes the difference in adsorption properties between the water displacement solution and water, it is not limited to using a substance that has low affinity for hydrocarbon solvents, which are the main components of the cleaning solution or water displacement solution, but high affinity for water. Specifically, examples include oil-water separation filters with water-repellent surface treatment, silica gel, and adsorbents using water-absorbing polymers.

[0113] In the cleaning apparatus 1 according to the fourth embodiment, a configuration was adopted in which water is removed from the water displacement liquid in the water displacement liquid tank 20, but a configuration can also be adopted in which water is removed from the water displacement liquid in the cleaning tank 10.

[0114] In this case, the water can be removed from the water displacement liquid by reducing the pressure inside the cleaning tank 10 with a vacuum pump 71, or a centrifugal separator (not shown) can be installed on the discharge side downstream of the cleaning tank 10, and the water can be removed by separating it from the water displacement liquid using the difference in specific gravity between the water displacement liquid and water within this centrifugal separator.

[0115] The cleaning device 1 according to the fourth embodiment described above can also provide the same effects as those of the embodiments described so far.

[0116] Next, other embodiments of the present invention will be described. Figure 8 is a schematic diagram showing an overview of the cleaning apparatus 1 according to the fifth embodiment of the present invention. In the cleaning apparatus 1 according to the fifth embodiment shown in Figure 8, components with the same reference numerals as in the previous embodiments have the same configuration and function, so their description will be omitted.

[0117] The washing apparatus 1 according to the fifth embodiment, like the washing apparatus 1 according to the second embodiment, omits the dewatering tank 40 from the washing apparatus 1 according to the first embodiment. In the washing apparatus 1 according to the fifth embodiment, as with the washing apparatus 1 according to the second embodiment, the process of removing water from the water displacement liquid is carried out in the water displacement liquid tank 20, but the method of removing water from the water displacement liquid differs from that of the washing apparatus 1 according to the second embodiment. The configuration for this is described below.

[0118] In the cleaning apparatus 1 according to the fifth embodiment, a gas introduction pipe 150 is provided below the water displacement liquid tank 20, and dry gas with a humidity of less than 100% can be blown into the water displacement liquid tank 20 from below through this gas introduction pipe 150. The gas blown into the water displacement liquid tank 20 through the gas introduction pipe 150 can be air or nitrogen gas. Since the vapor pressure of water is higher than that of the hydrocarbon solvent, which is the main component of the water displacement liquid, moisture is preferentially vaporized and removed from the system as water vapor by bubbling such air or nitrogen gas.

[0119] In the cleaning apparatus 1 according to the fifth embodiment, the water displacement liquid tank 20 is provided with a pipe 57 connecting the water displacement liquid tank 20 to the outside of the cleaning apparatus, but a vacuum pump 72 is not provided in this pipe 57. With this configuration, the water in the water displacement liquid is discharged to the outside of the cleaning apparatus.

[0120] In the cleaning apparatus 1 according to the fifth embodiment, in order to separate and discharge water as water vapor from a liquid hydrocarbon solvent such as a water displacement liquid, heat is supplied and water vapor is transported out of the system by blowing a dry gas with a humidity of less than 100% into the water displacement liquid, thereby discharging the water out of the system. Although not particularly limited, this gas can be compressed air that has passed through a dryer supplied as a utility in a typical factory, or nitrogen gas from a nitrogen gas generator.

[0121] Generally, in order to separate and discharge water as water vapor from liquid hydrocarbon solvents such as water displacement solutions, a mechanism is needed to supply the amount of heat required to cause the phase change of water into water vapor, and a mechanism is needed to transport the generated water vapor out of the system.

[0122] For example, in a water displacement liquid tank 20 that stores water displacement liquid, a heating means is used to supply the water displacement liquid with the amount of heat necessary for vaporization, while the pressure inside the tank is reduced to below the vapor pressure of water, thereby boiling the water in the water displacement liquid, which is then discharged using a vacuum pump or the like.

[0123] In the cleaning apparatus 1 according to the fifth embodiment, the water displacement liquid tank 20 is provided with a function to separate and discharge water from the water displacement liquid as water vapor, but such a function may also be provided to the cleaning tank 10.

[0124] The cleaning device 1 according to the fifth embodiment described above can also provide the same effects as those of the embodiments described so far.

[0125] As described above, the cleaning method according to the present invention comprises a water displacement liquid spraying step in which a water displacement liquid is sprayed onto the object to be cleaned in a cleaning tank, and a cleaning liquid immersion step in which the object to be cleaned is immersed in the cleaning liquid in the cleaning tank after the water displacement liquid spraying step. Therefore, according to the cleaning method according to the present invention, the water displacement liquid spraying step and the cleaning liquid immersion step can be performed in the same cleaning tank, which can reduce the size and installation area of ​​the cleaning equipment. Furthermore, according to the cleaning method according to the present invention, since the water displacement liquid is brought into contact with the object to be cleaned by spraying, there is no need to immerse the object to be cleaned in the water displacement liquid, which reduces the amount of water displacement liquid required and makes it possible to reduce operating costs.

[0126] Furthermore, the cleaning apparatus according to the present invention has a spray nozzle that sprays the water displacement liquid introduced in the water displacement liquid introduction pipe onto the object to be cleaned, and a drain section that discharges the water displacement liquid used in the cleaning tank to the outside of the cleaning tank. With such a cleaning apparatus according to the present invention, the water displacement liquid used in the cleaning tank is discharged from the drain section, and the cleaning tank can be used for cleaning with cleaning liquids other than the water displacement liquid, thus reducing the size and installation area of ​​the cleaning apparatus. In addition, with the cleaning apparatus according to the present invention, since the water displacement liquid is brought into contact with the object to be cleaned by spraying, there is no need to immerse the object to be cleaned in the water displacement liquid, the amount of water displacement liquid required is reduced, and operating costs can be reduced.

[0127] Although the present invention has been described above based on embodiments, the present invention is not limited to the above embodiments. Various modifications to the above embodiments or combinations of embodiments within the same and equivalent scope as the present invention are also included in the scope of the present invention. [Explanation of symbols]

[0128] 1. Washing device 5. Distillation regeneration tank 7...Cooler 10. Washing tank 11. Spray nozzle 13...Drain section 15. Transducer 20. Water displacement fluid tank 30... Cleaning solution tank 33. Coarse cleaning solution tank 34. Rinse fluid tank 37. Temperature control coil 38... Temperature control coil 39... Temperature control coil 40...Dehydration tank 41...valve 43...valve 44...valve 51... Valve 52. Water displacement fluid introduction piping 53. Cleaning fluid introduction piping 55. Cleaning fluid steam introduction piping 56. Piping (between the cleaning tank and the outside of the cleaning device) 57. Piping (between the water displacement fluid tank and the outside of the cleaning device) 58. Piping (between the cleaning fluid tank and the outside of the cleaning device) 59. Piping (between the dewatering tank and the outside of the washing device) 60... Piping (between the washing tank and the dewatering tank) 61. Water displacement fluid recovery piping (piping for recovering water displacement fluid into a water displacement fluid tank) 63. Cleaning fluid recovery piping (piping for recovering cleaning fluid into the cleaning fluid tank) 65. Piping (between the cleaning solution tank and the distillation regeneration tank) 66. Piping (between the distillation regeneration tank and the cleaning solution tank) 71. Vacuum pump 72. Vacuum pump 73. Vacuum pump 74. Vacuum pump 81... Pump 82... pump 83... Pump 84... pump 85... pump 91... Three-way valve 93... Three-way valve 94. Three-way valve 95... Three-way valve 123...Water discharge part 130...Water storage tank 135... Piping (between the water displacement fluid tank and the water storage tank) 142... Valve 150...Gas introduction piping W...Metal processed products (objects to be cleaned)

Claims

1. A water displacement liquid injection step in which a water displacement liquid is sprayed onto the object to be cleaned in a cleaning tank, Following the water displacement liquid injection step, a cleaning liquid cleaning step is performed in which the object to be cleaned is cleaned with a cleaning liquid in the cleaning tank. A cleaning method characterized by comprising a cleaning solution vaporization step of vaporizing the cleaning solution.

2. The cleaning method according to claim 1, further comprising a water removal step of removing water from the water displacement liquid used in the cleaning tank.

3. The cleaning method according to claim 1, characterized in that the cleaning step is performed by immersing the object to be cleaned in a cleaning solution.

4. The cleaning method according to claim 1, characterized in that the cleaning step is performed by spraying a cleaning solution onto the object to be cleaned.

5. The cleaning method according to claim 1, characterized in that the cleaning liquid vaporization step involves introducing the vapor of the cleaning liquid into the cleaning tank and then reducing the pressure inside the cleaning tank.

6. The cleaning method according to claim 1, characterized in that the cleaning liquid vaporization step is performed by reducing the pressure inside the cleaning tank to vaporize the cleaning liquid adhering to the object to be cleaned.

7. The cleaning method according to any one of claims 1 to 4, characterized in that the cleaning solution contains a liquid hydrocarbon, and the liquid hydrocarbon is normal paraffin, isoparaffin, naphthene, or a mixture of two or more of normal paraffin, isoparaffin, and naphthene.

8. The cleaning method according to claim 7, characterized in that the water displacement solution is obtained by adding a surfactant to the cleaning solution.

9. A washing tank in which the object to be washed is placed and the object to be washed is washed, A water displacement liquid introduction pipe for introducing the water displacement liquid into the aforementioned cleaning tank, A cleaning device characterized by having a spray nozzle that sprays the water-displacement liquid introduced in the water-displacement liquid introduction pipe onto the object to be cleaned.

10. The washing tank has a drain section for discharging the water displacement liquid used in the washing tank to the outside of the washing tank, The washing apparatus according to claim 9, characterized in that it has a dewatering tank for storing the water displacement liquid discharged from the drain section and for removing water from the stored water displacement liquid.

11. The dewatering tank has a vacuum pump to reduce the pressure inside the tank, The cleaning apparatus according to claim 10, characterized in that water is removed by vaporizing the water from the stored water displacement liquid by operating the vacuum pump.

12. The dewatering tank has an introduction pipe for a gas with a humidity of less than 100%, The cleaning apparatus according to claim 10, characterized in that moisture is removed by vaporizing the water from the stored water displacement liquid by bringing the gas into contact with the water displacement liquid.

13. The washing apparatus according to claim 10, characterized in that, in the dewatering tank, water is removed by separating it from the stored water displacement liquid by utilizing the difference in specific gravity between the water displacement liquid and water.

14. The cleaning tank has a vacuum pump to reduce the pressure inside the tank, The cleaning apparatus according to claim 9, characterized in that the water is vaporized and removed from the water displacement liquid used in the cleaning tank by operating the vacuum pump.

15. The washing tank has a discharge section for discharging the water-displaced liquid used in the washing tank to a centrifugal separator. The cleaning apparatus according to claim 7, characterized in that water is removed by separating water from the water displacement liquid by utilizing the difference in specific gravity between the water displacement liquid and water within the centrifugal separator.

16. The cleaning tank has a cleaning fluid introduction pipe for introducing cleaning fluid, The cleaning apparatus according to claim 9, characterized in that the object to be cleaned is immersed in the cleaning liquid introduced through the cleaning liquid introduction pipe.

17. The cleaning tank has a vibrator, The cleaning apparatus according to claim 16, characterized in that vibration is applied to the cleaning liquid by operating the vibrator.

18. The cleaning apparatus according to claim 9, further comprising a cleaning liquid steam introduction pipe for introducing the cleaning liquid steam into the cleaning tank.

19. The cleaning tank has a cleaning fluid introduction pipe for introducing cleaning fluid, The cleaning apparatus according to claim 9, characterized in that the cleaning liquid introduced through the cleaning liquid introduction pipe is sprayed onto the object to be cleaned using the spray nozzle.

20. The cleaning tank has a vacuum pump to reduce the pressure inside the tank, The cleaning apparatus according to claims 16 to 19, characterized in that the cleaning liquid adhering to the object to be cleaned is vaporized by operating the vacuum pump.

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