Method for cleaning objects to be cleaned

Abstract

This invention provides a cleaning method for objects to be cleaned that allows for the removal of large amounts of oil without using large quantities of cleaning solvents, while also considering safety and the global environment, and keeping cleaning costs low. [Solution] The process involves a heating step of heating the object to be cleaned 14 to 100°C or higher by immersing it in heated oil 4 at 100°C or higher; a peeling step of physically removing dirt attached to the object to be cleaned 14 by bringing it into contact with heated water 6 and using the pressure of the generated steam; a solvent cleaning step of removing any remaining oil from the object to be cleaned 14 by bringing it into contact with a cleaning solvent 13 having a boiling point lower than the temperature of the object to be cleaned 14 after the peeling step; and a drying step of evaporating the cleaning solvent 13 attached to the object to be cleaned 14 using the heat of the object to be cleaned 14 while maintaining the temperature of the object to be cleaned 14 higher than the boiling point of the cleaning solvent 13.

Description

Technical Field

[0001] The present invention relates to a cleaning method for removing dirt adhering to objects to be cleaned such as mechanical parts, electronic parts, and medical devices.

Background Art

[0002] When manufacturing industrial products such as metals, ceramics, and resins, heat is generated during processing such as pressing and cutting. Therefore, it is common to perform operations while cooling the material with processing oil. Therefore, when such processing is performed, dirt such as oil and cutting chips adheres to the industrial products that are the objects to be cleaned in the present application, and thus it is necessary to remove them.

[0003] When cleaning such objects to be cleaned, conventionally, as shown in Patent Document 1, it has been common to use a large amount of cleaning solvents in liquid cleaning and steam cleaning. However, the use of such a large amount of cleaning solvents has caused photochemical smog, ozone layer depletion, soil pollution, and公害 (public nuisance). In addition, in 1995, Freon 113, 1,1,1-trichloroethane was globally phased out, and in recent years, reducing carbon dioxide emissions has become a global issue. Therefore, in order to solve such problems, it is necessary to significantly reduce the amount of cleaning solvents used during cleaning.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, cleaning for purposes such as removing grease, carbon deposits, and water-soluble cutting fluids often requires particularly strong physical cleaning or large amounts of cleaning solvent to remove large quantities of oil. Therefore, it was still necessary to use large amounts of cleaning solvent. Furthermore, as described in Reference 1, when vapor cleaning is performed using cleaning solvents, there are concerns about the diffusion of solvent vapors into the atmosphere and the consumption of the cleaning solvent, which can easily lead to problems with environmental impact, safety, and cleaning costs.

[0006] Therefore, this invention aims to solve the aforementioned problems and provide a cleaning method for objects to be cleaned that can remove large amounts of oil without using large amounts of cleaning solvent, while also considering safety and the global environment and keeping cleaning costs low. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention provides a heating step in which the object to be cleaned is heated to 100°C or higher by immersing it in heated oil heated to any temperature of 100°C or higher, and a peeling step in which the object to be cleaned is brought into contact with heated water after the heating step, thereby physically peeling off the dirt attached to the object by the pressure of the steam generated when the object comes into contact with the heated water. The heated water can be set to any temperature of 100°C or lower depending on the cleaning purpose.

[0008] Furthermore, the temperature of the object to be cleaned after the heating process is 100°C or higher, and during the subsequent stripping and cleaning process, the object to be cleaned at 100°C or higher is brought into contact with heated water. Therefore, the temperature of the object to be cleaned during this stripping and cleaning process is lower than the temperature of the heated oil, and equal to or higher than the temperature of the heated water. After the stripping process, a solvent cleaning process is performed to remove any remaining oil from the object to be cleaned by bringing it into contact with a liquid cleaning solvent having a boiling point lower than the temperature of the object after the stripping and cleaning process.

[0009] Following the solvent cleaning step, a drying step is performed in which the cleaning solvent adhering to the object is evaporated by the heat of the object, while the temperature of the object to be cleaned is kept higher than the boiling point of the cleaning solvent. In order to keep the temperature of the object to be cleaned higher than the boiling point of the cleaning solvent as described above, it is preferable to proceed to the drying step of the object to be cleaned as soon as possible after the solvent cleaning step.

[0010] Furthermore, the oil used in the method of the present invention is not particularly limited, but processing oils, rust-preventive oils, heat treatment oils, polishing fluids, etc. are preferred, and the cleaning solvent used in the method of the present invention is also not particularly limited, but chlorine-based solvents, fluorine-based solvents, alcohol-based solvents, etc. are preferred.

[0011] Furthermore, the solvent cleaning step may be carried out by showering the object to be cleaned with the cleaning solvent, or by immersing the object to be cleaned in the cleaning solvent. [Effects of the Invention]

[0012] As described above, the present invention involves physically removing dirt attached to the object to be cleaned in a peeling step, and then performing a solvent cleaning step after the peeling step to remove any oil remaining on the object to be cleaned. Therefore, even for stubborn dirt on objects that were previously difficult to remove, the continuous physical and chemical removal of dirt in the peeling step and solvent cleaning step makes it possible to easily and reliably remove dirt attached to the object to be cleaned. Thus, even if a large amount of oil is attached to the object to be cleaned before cleaning, it is possible to remove the oil quickly and effectively.

[0013] Furthermore, since the present invention does not involve steam cleaning with a cleaning solvent, it is not necessary to use large quantities of cleaning solvent, and the consumption of such cleaning solvent can be kept low. Therefore, it is possible to reduce cleaning costs while also considering safety and the global environment.

[0014] Furthermore, as described above, the drying process of the present invention involves maintaining the temperature of the object to be cleaned above the boiling point of the cleaning solvent after the solvent cleaning process, and evaporating the cleaning solvent adhering to the object using the heat of the object. Therefore, since no special equipment for drying is required, the object to be cleaned can be dried quickly and reliably at low cost. [Brief explanation of the drawing]

[0015] [Figure 1] A conceptual diagram of Embodiment 1 illustrating the present invention. [Example 1]

[0016] Embodiment 1 of the present invention will be explained in Figure 1. (1) is an oil tank, which is equipped with a first heater (2) and a first temperature sensor (3) at its bottom. Oil (4) that can be heated to any temperature of 100°C or higher is stored in the oil tank (1). Adjacent to the oil tank (1) is a water tank (5), which is equipped with water (6). A second heater (7) and a second temperature sensor (8) are provided at the bottom of the water tank (5), and the water (6) in the water tank (5) can be constantly heated and maintained at a constant temperature by the second heater (7) and the second temperature sensor (8).

[0017] As shown in Figure 1, a solvent tank (10) is placed adjacent to the water tank (5), and a third heater (11) and a third temperature sensor (12) are provided at the bottom of the solvent tank (10). A cleaning solvent (13) is stored inside the solvent tank (10), and the temperature of the cleaning solvent (13) can be heated by the third heater (11) and maintained at a constant temperature by the third temperature sensor (12).

[0018] The cleaning method for the object to be cleaned (14) using the cleaning apparatus configured as described above will be explained below. First, before starting the cleaning, the oil (4) in the heated oil tank (1) is heated to a target temperature of 100°C or higher and below the boiling point of the oil (4) using the first heater (2), and this temperature is maintained using the first temperature sensor (3). The oil (4) can be heated to any temperature between 100°C or higher and below the boiling point of the oil, depending on the purpose of cleaning. In addition, the water (6) stored in the water tank (5) is heated to a predetermined temperature of 100°C or lower using the second heater (7), and this temperature is maintained using the second temperature sensor (8).

[0019] Furthermore, the cleaning solvent (13) stored in the solvent tank (10) is heated to a predetermined temperature as described below by the third heater (11), and the temperature is maintained by the third temperature sensor (12).

[0020] Next, the cleaning process for the object to be cleaned (14) in this embodiment will be described. First, the object to be cleaned (14) is heated to 100°C or higher by immersing it in an oil tank (1) containing oil (4) heated to 100°C or higher. After the object to be cleaned (14) has been heated to a predetermined temperature of 100°C or higher in this heating process, the object to be cleaned (14) is removed from the oil tank (1) and a peeling process is performed.

[0021] In this peeling process, the object to be cleaned (14), which has been heated to 100°C or higher as described above, is immersed in the heated water (6) in the water tank (5). By immersing the object to be cleaned (14), which has been heated to 100°C or higher, in the heated water (6), the heated water (6) comes into contact with the object to be cleaned (14) and evaporates instantaneously. As a result, the pressure of the water vapor generated during the instantaneous evaporation of the heated water (6) allows for the physical and instantaneous peeling of dirt such as oil (4) and metal shavings attached to the object to be cleaned (14).

[0022] After the above peeling process is completed, a solvent liquid washing process is performed. Regarding this solvent liquid washing process, the washed object (14) immersed in the heated water (6) in the water tank (5) during the peeling process as described above is taken out and immersed in the cleaning solvent (13) in the solvent tank (10). Here, as described above, the washed object (14) is heated to 100 °C or higher in the heating process and then immersed in the heated water (6) at 100 °C or lower containing boiling water in the peeling process. Therefore, since the temperature of the washed object (14) after the peeling process is cooled by the heated water (6), it becomes the same as or higher than the temperature of the heated water (6).

[0023] Also, the cleaning solvent (13) in the solvent tank (10) is one having a boiling point lower than the temperature of the washed object (14) after the peeling process, and is heated to a temperature below the boiling point of the cleaning solvent (13) by the third heater (11) in the solvent tank (10), and the heating state is maintained by the third temperature sensor (12).

[0024] And by passing through this solvent liquid washing process, the dirt on the washed object (14) that could not be completely removed in the above peeling process is brought into contact with the cleaning solvent (13), so that the dirt can be chemically removed. Therefore, by continuously performing the peeling washing and the solvent liquid washing as described above, it is possible to physically and chemically remove the dirt on the strong washed object (14) that was difficult to remove conventionally from the washed object.

[0025] In addition, in the solvent liquid washing process, the washed object (14) can be immersed in the cleaning solvent (13) for about several seconds to several tens of seconds to sufficiently remove the dirt on the washed object (14). Also, in this embodiment, the solvent liquid washing is performed by immersing the washed object (14) in the cleaning solvent (13) as described above, but in other different embodiments, it is not limited to this, and the solvent liquid washing can also be performed by spraying the cleaning solvent (13) on the washed object (14) in the form of a shower.

[0026] After the solvent cleaning process is completed, the object to be cleaned (14) is dried. In this drying process, first, the object to be cleaned (14), which has been immersed in the cleaning solvent (13) in the solvent tank (10) as described above, is removed and left to stand in an open area. In the solvent cleaning process, the cleaning can be completed by immersing the object to be cleaned (14) for several seconds to tens of seconds. Therefore, by proceeding to the drying process immediately after the solvent cleaning process is completed as described above, the temperature of the object to be cleaned (14) can be maintained at a temperature higher than the boiling point of the cleaning solvent (13) during the drying process, just as during the solvent cleaning process.

[0027] Therefore, the cleaning solvent (13) adhering to the object to be cleaned (14) during the solvent cleaning process will evaporate immediately due to the heat of the object to be cleaned (14), which is higher than the boiling point of the cleaning solvent (13). As a result, the object to be cleaned (14) can be dried quickly without the need for any special drying equipment. [Explanation of Symbols]

[0028] 4 oil 6 water 13 Cleaning solvent 14. Items to be washed

Claims

1. A method for cleaning an object to be cleaned, characterized by comprising: a heating step of heating the object to be cleaned to 100°C or higher by immersing it in heated oil heated to any temperature of 100°C or higher; a peeling step of performing peeling cleaning by bringing the object to be cleaned into contact with heated water after the heating step, thereby physically peeling off the dirt attached to the object by the pressure of the steam generated when the object comes into contact with the heated water; a solvent cleaning step of removing any remaining oil from the object to be cleaned by bringing the object to be cleaned into contact with a liquid cleaning solvent having a boiling point lower than the temperature of the object after the peeling step; and a drying step of evaporating the cleaning solvent attached to the object by the heat of the object to be cleaned while maintaining the temperature of the object to be cleaned higher than the boiling point of the cleaning solvent after the solvent cleaning step.

2. The above solvent cleaning step is characterized by showering the object to be cleaned with the cleaning solvent, or by immersing the object to be cleaned with the cleaning solvent, as described in claim 1.

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