JP2017155274A - Circulation type high pressure steam washing method of metal article by soft hydrothermal process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing method that can surely wash metal article soiled by cutting fluid or the like without using a cleaning liquid such as organic solvent.SOLUTION: The washing method according to the present invention includes a high pressure steam washing step (step ST9) in which, via a pressure vessel containing aluminum pipes soiled with cutting fluid, steam is circulated in a state of highly saturated steam having a vapor saturation degree not less than 100% and the cutting fluid is washed by a soft hydrothermal process. It was confirmed that fats/oils such as cutting fluid and other organic material can be reliably wash and removed from metal article.SELECTED DRAWING: Figure 2

Description

  The present invention uses a chemical characteristic of a soft hydrothermal process to wash a metal product on which foreign matter (dirt) including fats and oils such as cutting fluids adheres, and a metal product in a circulation type high-pressure steam cleaning method. Regarding the method.

  Metal parts such as metal parts manufactured through cutting and grinding processes need to be cleaned to remove dirt such as cutting fluid and solid foreign substances adhering to the surface in the processing step. Conventionally, an organic solvent such as a fluorine-based solvent or a hydrocarbon-based solvent is generally used as a cleaning agent to clean and remove oils and fats adhering to a metal product. Such a cleaning method is disclosed in Patent Documents 1 and 2, for example. In Patent Document 2, water, an alkaline solution, or an organic solvent is used for finish cleaning of the metal strip after the oil is removed.

  Here, the present inventors applied the chemical characteristics of a soft hydrothermal process (high temperature and high pressure water and steam of 200 ° C. or less) with almost no basic research examples, and made it impossible to perform at high temperatures in existing autoclaves. It has been found that it is possible to inactivate resistant proteins or enzymes and bacterial endotoxins (Patent Documents 3, 4, and 5). Moreover, the novel algal oil extraction method which enabled extraction of algal oil efficiently without using the organic solvent, the ultrasonic wave, or the mechanical method to which the said soft hydrothermal process was applied was discovered (patent document 6).

JP 2014-188478 A JP-A-7-243070 JP 2011-083206 A JP 2010-075619 A JP 2009-240206 A JP-A-2015-221007

  In a generally used cleaning method using an organic solvent, it is necessary to treat the organic solvent after use from the viewpoint of environmental protection and the like, and an organic solvent such as a hydrogen fluoride solvent is generally expensive. Accordingly, ultrasonic cleaning using water, steam cleaning using high-temperature and high-pressure steam, and the like are desirable.

  However, conventionally, there has not been proposed a cleaning method using water or steam that can reliably clean fats and oils. Further, when a metal product, for example, an aluminum part is cleaned using high-temperature steam, aluminum oxide or aluminum hydroxide, which is a by-product generated in the cleaning process, remains in a whitened state on the surface. Furthermore, these cleaning methods generally require a drying step after the cleaning. If the drying process can be omitted, the working efficiency can be increased.

  An object of the present invention is to pay attention to the chemical characteristics of a soft hydrothermal process, and to reliably clean cutting fluids and fats and oils adhering to metal products using water vapor by applying the soft hydrothermal process. The purpose of this is to propose a flow-through high-pressure steam cleaning method for metal products.

  In order to solve the above-mentioned problems, the flow-type high-pressure steam cleaning method for metal products according to the present invention is configured so that water vapor is converted to steam saturation via a pressure vessel containing a metal product to which foreign substances including organic matter are attached. Is characterized in that it includes a high-pressure steam cleaning step in which foreign substances are circulated in a highly saturated steam state that does not fall below 100% and the foreign substances are cleaned from the metal product by a soft hydrothermal process.

The relationship between the saturated water vapor amount and the temperature and pressure can be derived based on the following equation of state of gas.
PV = nRT (PV = G / M · RT)
P: Pressure (MPa)
V: Volume (dm ³ )
n: Number of moles (mol)
G: Mass of H ₂ O (kg)
M: Molecular weight of H ₂ O (18.015)
R: Gas constant (8.31 × 10 ⁻³ dm ³ · MPa / K · mol)
T: Temperature (K [° C. + 273 ° C.])

Highly saturated water vapor refers to saturated water vapor with a high degree of steam saturation and water vapor at a pressure higher than the saturated water vapor pressure. The soft hydrothermal process refers to a chemical reaction using highly saturated steam at 200 ° C. or lower as a reaction medium. The high steam saturation means a state where the steam saturation is 100% or more, and the steam saturation is expressed by the following equation.
{Vapor density (kg / m ³ ) / Saturated water vapor density (kg / m ³ )} × 100 (%)

  In the method of the present invention, highly saturated water vapor is circulated through a pressure vessel, which is a washing tank, so that dirt containing organic substances such as oils and fats attached to metal products in the pressure vessel is washed. . According to the experiments by the present inventors, it has been confirmed that organic substances such as fats and oils, for example, cutting oil adhering to the metal working process can be removed reliably.

  In the method according to the present invention, a soft hydrothermal process is used, and cleaning treatment is performed while highly saturated water vapor is circulated through a pressure vessel. That is, in the high-pressure steam cleaning process, steam at a predetermined pressure and temperature is always supplied to the pressure vessel at a predetermined flow rate from the supply side (upstream side) through a steam supply valve maintained at a predetermined opening degree. On the water vapor discharge side of the pressure vessel, the opening degree of the exhaust valve is adjusted according to the internal pressure of the pressure vessel, and control is performed so that the internal temperature and the internal pressure of the pressure vessel are respectively maintained at predetermined values.

  By performing the cleaning process while circulating highly saturated water vapor through the pressure vessel, the amount of condensed water generated in the metal washing process is greatly reduced, and the generated condensed water is quickly removed from the pressure vessel. Is done. In other words, the metal article to be cleaned can be dried to a predetermined degree during the high-pressure steam cleaning step by circulating the highly saturated steam. Thereby, the drying time of the metal product after the cleaning process can be greatly shortened, and further, the drying process can be omitted, and the work time required for the cleaning process of a series of metal products can be greatly shortened.

  In the method of the present invention, usually, water vapor is supplied to the pressure vessel and the pressure vessel is heated by a heater from the outside to increase the internal temperature and the internal pressure of the pressure vessel to a predetermined temperature and pressure. It includes a temperature rise and pressure boosting step for steam saturation. Next to the temperature raising / pressurizing step, the internal temperature and internal pressure of the pressure vessel are maintained at a predetermined cleaning temperature, a predetermined cleaning pressure, and a predetermined steam saturation, over the predetermined cleaning time. A high pressure steam cleaning process is performed.

Depending on the physical properties of the object to be cleaned and the physical properties of the cutting oil and fats and oils, it may be desirable to perform an air exclusion process for removing air from the pressure vessel containing the metal product before the temperature raising and pressure increasing process. is there.

  The method of the present invention is suitable for use in cleaning and removing dirt containing fats and oils such as cutting fluid from metal products. For example, it can be used for cleaning aluminum products to which dirt containing cutting fluid (pressing fluid) is attached.

  According to the experiments by the present inventors, such an aluminum product was cleaned (cutting fluid: volatile press working oil manufactured by Sugimura Chemical Co., Ltd., product name “Sunpress S-108KA”). Has been confirmed to be reliably removed by washing. In particular, in the high-pressure steam cleaning process, at least 5 minutes or 115 ° C. or more in a state where the inside of the pressure vessel is maintained at a cleaning temperature of 105 ° C. or more, at least 20 minutes, or 120 ° C. or more. It was confirmed that the cutting fluid can be reliably removed by circulating water vapor that does not fall below 100% of the steam saturation over a cleaning time of at least 10 minutes in the state maintained at the cleaning temperature. Moreover, it was confirmed that the aluminum product after washing | cleaning is in a dry state substantially, and the drying process after washing | cleaning is unnecessary. Further, on the surface of the aluminum product after the cleaning, a white product of aluminum oxide or aluminum hydroxide, which is a by-product by steam cleaning, was not substantially confirmed and was in a good surface state.

1 is a schematic configuration / piping system diagram of a small cleaning apparatus to which the present invention is applied. It is a schematic flowchart which shows the processing operation of the small washing | cleaning apparatus of FIG. It is a flowchart which shows a door seal subroutine (step ST3 of FIG. 2). It is a flowchart which shows a boiler subroutine (step ST4 of FIG. 2). It is a flowchart which shows a pressure vessel (can body) heater subroutine (step ST5 of FIG. 2). It is a flowchart which shows an example of a washing | cleaning subroutine (step ST9 of FIG. 2). It is a flowchart which shows the door seal cancellation | release subroutine (step ST11 of FIG. 2) for taking out the processed metal goods. It is a flowchart which shows an example of the preheating process of a small washing | cleaning apparatus. It is the chart and graph which show the result of the washing test. FIG. 10 is a chart showing the results of the cleaning test in FIG. 9 in more detail. It is a graph of the time-dependent change of the pressure of an example of a washing | cleaning test. It is a graph of the time-dependent change of the temperature of an example of a washing test. It is a graph of the time-dependent change of the opening degree of the steam supply valve of an example of a washing test. It is a graph of a time-dependent change of heater temperature of an example of a washing test. It is a graph of a time-dependent change of pressure and temperature of an example of a washing test. It is a graph of the time-dependent change of the pressure of the other example of a washing | cleaning test. It is a graph of the time-dependent change of the temperature of the other example of a washing | cleaning test. It is a graph of the time-dependent change of the opening degree of the steam supply valve of the other example of a washing | cleaning test. It is a graph of the time-dependent change of the heater temperature of the other example of a washing | cleaning test. It is a graph of the time-dependent change of the pressure and temperature of the other example of the washing test.

  Below, with reference to drawings, the embodiment of the small-sized washing device using the distribution type high-pressure steam washing method by the soft hydrothermal process of the present invention is described.

[overall structure]
FIG. 1 is a schematic configuration / piping system diagram showing a flow-type small cleaning device according to the present embodiment. A small cleaning apparatus 1 for cleaning a metal product includes a processing unit 2 for performing a high-pressure steam cleaning process, and the processing unit 2 is a pressure vessel 3 (a cleaning tank for cleaning a metal product (object to be cleaned)). Chamber). The pressure vessel 3 is provided with a heater 4 for heating the pressure vessel 3 from the outside, a temperature detection unit 5 for detecting the internal temperature and the internal pressure of the pressure vessel 3, and a pressure detection unit 6. An opening / closing mechanism 7 for the door 3a of the pressure vessel 3 is disposed.

  A boiler unit 10 for supplying water vapor to the pressure vessel 3 is disposed upstream of the pressure vessel 3 in the water vapor flow direction. The boiler unit 10 includes a boiler 11 and a boiler water supply tank 12. A vacuum pump 13 for evacuating the pressure vessel 3 and a drainage cooling unit 15 including a drainage tank 14 are disposed downstream of the pressure vessel 3 in the water vapor circulation direction.

  The operation of the high-pressure steam cleaning process of the small cleaning device 1 is controlled by the control panel 16. An operation / display unit 17 is connected to the control panel 16. The operation / display unit 17 includes a display screen 18 and a plurality of operation buttons 19. By operating the operation button 19, the temperature, pressure, and time during the cleaning process can be set and input. For example, it is set by a touch panel operation. The display screen 18 can display the apparatus operating state including the temperature and pressure during high-pressure steam cleaning.

  The main part of the piping system of the small cleaning apparatus 1 will be described with reference to FIG. In the pressure vessel 3 of the processing unit 2, a plurality of heaters 4 (H1 to H6) are arranged so as to surround the outer peripheral surface of the can body. The temperature detector 5 that detects the internal temperature of the pressure vessel 3 heated by the heater 4 includes, for example, an upper portion, a central portion, and a lower portion at the center position in the direction of the central axis within the horizontally placed pressure vessel 3. Three temperature sensors TE8, TE9, TE10 for detecting the temperature of the side portion, and two temperature sensors TE11, TE12 for detecting the temperatures of the downstream portion and the upstream portion in the central portion are provided. The pressure detection unit 6 that detects the internal pressure of the pressure vessel 3 includes one pressure sensor PT1 and one pressure gauge PT2.

  A boiler 11 is connected to the pressure vessel 3 via a steam supply pipe 21. The steam supply pipe 21 is provided with a steam supply electromagnetic valve 22 on the upstream side thereof, and a steam supply motor valve 23 maintained at a predetermined opening degree on the downstream side thereof. An exhaust motor valve 33 that is maintained at a predetermined opening degree according to the internal pressure detected by the pressure sensor PT1 is disposed downstream of the pressure vessel 3. The boiler 11 heats the soft water supplied from the boiler feed water tank 12 to generate water vapor. The generated water vapor is supplied to the pressure vessel 3 through the steam supply pipe 21. The boiler 11 is connected to the drainage tank 14 via a boiler drain pipe 24 and a boiler drain valve 25.

  The door opening / closing mechanism 7 attached to the inlet side of the pressure vessel 3 includes a compressor 26, a door opening electromagnetic valve 27, and a door tightening electromagnetic valve 28. An air supply pipe 34 and an exhaust pipe 31 are connected to the pressure vessel 3. Air is supplied to the pressure vessel 3 through the air supply pipe 34 and the vacuum pump water supply valve (air supply electromagnetic valve) 35. The exhaust pipe 31 is connected to the suction side of the vacuum pump 13 via a vacuum motor valve 32, and is connected to the drainage tank 14 via an exhaust motor valve 33. Further, water is supplied to the vacuum pump 13 through a vacuum pump water supply valve 35.

[High-pressure steam cleaning operation]
FIG. 2 is a schematic flowchart showing the high-pressure steam cleaning processing operation of the small cleaning device 1. As a processing operation mode, a single pattern or a plurality of types of patterns can be prepared, and these operation patterns can be set in the control panel 16. For example, the operator can select one of these by operating the operation button 19 of the operation / display unit 17.

In the high-pressure steam cleaning processing operation (hereinafter sometimes simply referred to as “cleaning processing operation”), the preheating process of the pressure vessel 3 is first performed, and the cleaning processing operation shown in FIG. 2 is performed after the preheating process. Is started. The preheating process will be described later (see FIG. 8).

  In the cleaning process operation, first, an object to be cleaned is put into the pressure vessel 3 and the door 3a is closed (step ST1), and the cleaning process is started (step ST2). In the cleaning process, a door seal subroutine (step ST3: see FIG. 3), a boiler subroutine (step ST4: see FIG. 4) and a pressure subroutine (can body) 3 heater subroutine (step ST5: see FIG. 5) are respectively performed. Then, the seal pressure of the door 3a is increased to the specified seal pressure, the steam pressure supplied from the boiler 11 is increased to the specified pressure, and the heat generation temperature of the heater 4 is increased to the specified temperature (steps ST6, 7, 8).

  After the preparatory process is completed in this way, a cleaning operation of the metal article that is the object to be cleaned is performed in the pressure vessel 3 (step ST9: air exclusion process, temperature rising / pressurizing process, cleaning process and drying process, FIG. 6). reference). After the cleaning is completed, the internal pressure of the pressure vessel 3 is returned to the atmospheric pressure (step ST10), the door seal is released (step ST11: see FIG. 7), the door 3a is opened and the object to be cleaned after being cleaned is taken out (step ST12). ). Hereinafter, each step will be further described.

  FIG. 3 is a flowchart showing a door seal subroutine (step ST3 in FIG. 2). When the object to be cleaned is put into the pressure vessel 3 and the door 3a is closed, this is detected by the door closing limit switches LS1 and LS2 (see FIG. 1) (step ST301), the door tightening electromagnetic valve 28 is opened, and the compressor 26 is turned on. Entering (turning on), holding at the set pressure, sealing the door 3a with the specified sealing pressure (steps ST302 and 303), turning off the compressor 26 (closing), and closing the door tightening electromagnetic valve 28 (step ST304). By this series of operations, the sealed state is maintained until the end of cleaning (steps ST302 to ST305). After cleaning, the door tightening electromagnetic valve 28 is closed, and then the opening valve is opened to turn on the vacuum pump. As a result, the seal of the door 3a is released.

  FIG. 4 is a flowchart showing the boiler subroutine (step ST4 in FIG. 2). During operation of the boiler 11 (step ST401), the feed water pump WP (see FIG. 1) is driven and controlled so that the water level is maintained between the low water level and the high water level (steps ST402 to ST405). Further, the built-in heater is controlled so that the pressure of the generated steam is maintained at the specified pressure (steps ST406 to 409). Thereby, the steam controlled to the specified pressure is supplied to the pressure vessel 3 side.

  FIG. 5 is a flowchart showing a pressure vessel (can body) heater subroutine (step ST5 in FIG. 2). During driving of the heater 4 (step ST501), on / off control of the heater 4 is performed so that the heat generation temperature is maintained at a specified temperature (steps ST502 to 505).

  FIG. 6 is a flowchart showing an example of the cleaning subroutine (step ST9 in FIG. 2). In FIG. 6, steps shown in steps ST1 to ST8 in FIG. 2 are preparation steps.

  In the cleaning processing operation, first, an air exclusion process of the pressure vessel 3 is performed. The exhaust motor valve 33 and the air supply electromagnetic valve 35 are closed, the vacuum pump 13 is turned on, the vacuum motor valve 32 and the vacuum pump water supply valve 35 are opened (steps ST901 and 902), and the internal pressure of the pressure vessel 3 is set to a specified negative pressure. Later, the vacuum motor valve 32 is closed, the vacuum pump 13 is turned off, and the vacuum pump water supply valve 35 is closed (steps ST903 and 904).

Next, opening / closing control of the steam supply motor valve 23 and the steam supply electromagnetic valve 22 is performed, and a temperature rising / pressurizing step (pulse pressure increasing) in which the pulse pressure is applied to the pressure vessel 3 by two pulses is performed to define the internal pressure of the pressure vessel 3 The cleaning pressure is increased to, for example, 0.086 MPa (steps ST905 to 914). In parallel with the pressure increasing operation, the internal temperature of the pressure vessel 3 is controlled by the heater 4 so as to become a specified cleaning temperature, for example, 115 ° C., and the steam saturation is also controlled so as not to fall below 100% ( (See the can heater subroutine in FIG. 5).

  Next, after waiting for the internal pressure to stabilize (step ST915), the cleaning process is performed while maintaining the cleaning pressure for a predetermined cleaning time, for example, 10 minutes or more (step ST916). In the cleaning process, the steam supply electromagnetic valve 22 is maintained in an open state, the steam supply motor valve 23 is maintained at a constant opening, for example, a large opening of 70%, and a predetermined flow rate of water vapor passes through the pressure vessel 3. Circulate. The control panel 16 (see FIG. 1) adjusts the opening degree of the exhaust motor valve 33 based on the internal pressure of the pressure vessel 3, and maintains the internal pressure and internal temperature of the pressure vessel 3 at predetermined washing pressure and washing temperature. . Thereby, highly saturated water vapor | steam distribute | circulates in the pressure vessel 3, and the to-be-washed | cleaned object (metal article) using a soft hydrothermal process is performed.

After the specified cleaning time has elapsed, the steam supply motor valve 23 and the steam supply electromagnetic valve 22 are closed and the pressure vessel 3 is evacuated to bring the internal pressure of the pressure vessel 3 to a pressure state slightly higher than atmospheric pressure. (Steps ST917, 918). Next, the exhaust motor valve 33 is closed, the vacuum pump water supply valve 35 is opened, and the internal pressure of the pressure vessel 3 is made slightly lower than the atmospheric pressure (step ST919-
921). After exhausting the pressure vessel 3 in this way, the air supply electromagnetic valve 35 is opened, and the pressure vessel 3 is blown for a specified blowing time (steps ST922 and ST923). The object to be cleaned in the pressure vessel 3 is dried through a drying process consisting of exhaust and ventilation.

  Thereafter, the vacuum motor valve 32 is closed, the vacuum pump 13 is turned off, and the vacuum pump water supply valve 35 is closed (step ST924).

  Next, FIG. 7 is a flowchart showing a door seal release subroutine (step ST11 in FIG. 2) for taking out a processed object to be cleaned. First, the vacuum pump 13 is turned on, the door opening solenoid valve 27 is opened, the state is maintained for a specified time to release the sealing pressure, the vacuum pump 13 is turned off, and the door opening solenoid valve 27 is closed (step) ST111-113). As a result, the door 3a can be opened. After this, the door 3a is opened and the object to be cleaned is taken out.

  When the operation of the small cleaning device 1 is finished, the heater 4 is turned off and the operation of the boiler 11 is stopped.

[Example of preheating process]
FIG. 8 is a flowchart showing an example of a preheating process of the small cleaning apparatus 1. As shown in this figure, the water vapor generated in the boiler 11 is supplied to the pressure vessel 3, and in parallel with this, the pressure vessel 3 is heated to bring the pressure vessel 3 in the normal temperature and normal pressure state to a predetermined specified pressure and The temperature is raised to a predetermined specified temperature, and the seal pressure of the door 3a is increased to the specified seal pressure (steps ST131 to ST138). These operations are the same as those in steps ST1 to ST8 shown in FIG. Thereafter, after maintaining the prescribed temperature and prescribed pressure for a certain period of time, water vapor is discharged from the pressure vessel 3 to return the internal pressure to atmospheric pressure (steps ST139 to 145).

(contents of the test)
The present inventors cleaned the cutting fluid and oils and fats using the small cleaning device 1 having the above-described configuration, and evaluated the cleaning results.

A pipe having an elongated circular cross section made of aluminum was used as a metal article to be cleaned, and a cleaning test was performed by applying a cutting oil to the outer peripheral surface of the pipe. The product name “Sunpress S-108KA” (manufacturer: Sugimura Chemical Co., Ltd.), which is a volatile press working oil, was used as the cutting fluid.

  The cleaning test was performed for various combinations of the cleaning temperature (° C.) and the cleaning time (minutes) in the cleaning process. In the cleaning process, when the set temperature (external heater set value) of the heater arranged outside the pressure vessel (chamber) is the same as the cleaning temperature in the pressure vessel, the cleaning temperature is lowered And the test was conducted for the case where it was raised.

  The evaluation of the cleaning result was visually performed in two items, that is, the degree of removal of the cutting fluid and the fats and oils of the pipe after cleaning, and the degree of appearance due to whitening of aluminum hydroxide on the pipe surface. “Cleaning judgment (oil)”, which is an evaluation of the degree of cutting fluid removal, was performed by dividing the cutting fluid and oil removal status into three stages: “good”, “neither”, and “bad”. . “Cleaning judgment (appearance)”, which is an evaluation of the degree of appearance after cleaning, was also performed by assigning the appearance to three levels: “good”, “neither”, and “bad”. In these two evaluations, the cleaning conditions (cleaning temperature and cleaning time) determined to be “good” were determined to be “good” in the comprehensive evaluation.

  FIG. 9A shows a list of test results. FIG. 9B is a graph in which the test result of the cleaning judgment (oil) is plotted when the horizontal axis indicates the cleaning time (minutes) and the vertical axis indicates the cleaning temperature (° C.). c) is a graph in which cleaning determination (appearance) is similarly plotted.

  As can be seen from these figures, the cleaning temperature is 105 ° C., the cleaning time is 20 minutes, or the cleaning temperature is 120 ° C., the cleaning time is 5 minutes, or the cleaning temperature is 115 ° C., and the cleaning time is 10 minutes. Thus, it was confirmed that the cutting fluid adhering to the aluminum pipe could be reliably removed, and that the appearance quality such as whitening was not deteriorated on the pipe surface.

  FIG. 10 shows a list of specific test results for reference. FIG. 10A shows the results of each test when the set temperature (external heater set value) of the heater arranged outside the pressure vessel is the same as the wash temperature inside the pressure vessel in the cleaning step. FIG. 10B is a list showing the results of each test when the heater set temperature (external heater set value) is set to a value 3 degrees lower than the cleaning temperature. The temperature difference is shown in parentheses following the test date. FIG. 10C is a list showing the results of each test when the heater set temperature (external heater set value) is set to a value 10 degrees higher than the cleaning temperature.

  11A to 11E are graphs showing changes with time of parameters in the pressure vessel in the cleaning process employed in one of the cleaning tests evaluated as “good” as a reference for reference. Specifically, FIG. 11A is a graph showing the change over time of each control parameter in the pressure vessel used in the cleaning test when the cleaning temperature is 115 ° C. (heater setting temperature 115 ° C.) and the cleaning time is 10 minutes. 11B shows the temperature change, FIG. 11C shows the opening change of the steam supply valve, FIG. 11D shows the heater temperature, and FIG. 11E shows both the detailed pressure and temperature change in the cleaning process. .

  On the other hand, FIGS. 12A to 12E show changes with time of parameters in the pressure vessel in the cleaning process adopted in one of the cleaning tests evaluated as “None” as a reference. A graph is shown. Specifically, FIG. 12A is a graph showing the change over time of each control parameter in the pressure vessel used in the cleaning test when the cleaning temperature is 115 ° C. (heater set temperature 115 ° C.) and the cleaning time is 5 minutes. 12B shows the temperature change, FIG. 12C shows the opening change of the steam supply valve, FIG. 12D shows the heater temperature, and FIG. 12E shows both the detailed pressure and temperature change in the cleaning process. .

[Other embodiments]
The above example is a case where the cleaning method of the present invention is used for cleaning an aluminum pipe to which a cutting fluid is adhered. The method of the present invention is not limited to the above example, but for cleaning other types of metal products, parts made of various metal materials such as iron and copper, cutting oils and other fats and oils to which members are attached. Can be used. Furthermore, it can be used for cleaning foreign matters (dirt) including organic substances adhering to metal products as well as fats and oils. In other words, the pressure, temperature, steam saturation, and cleaning time in the pressure vessel should be set appropriately according to the material of the metal product to be cleaned and the type of organic matter such as oils and fats adhering thereto. Thus, it is possible to obtain a good cleaning result.

  In the above example, as shown in FIG. 6, in the cleaning process operation, an air removal process for removing air from the pressure vessel containing the metal product is performed (steps ST901 to ST904). The air removing step can be omitted depending on the physical properties of the object to be cleaned and the physical properties of the cutting oil and fats and oils, and is not an essential step.

1 Small cleaning device 2 Processing unit 3 Pressure vessel (chamber)
3a Door 4 Heater 5 Temperature detection unit 6 Pressure detection unit 7 Opening and closing mechanism 10 Boiler unit 11 Boiler 12 Boiler feed tank 13 Vacuum pump 14 Drain tank 15 Drain cooling unit 16 Control panel 17 Operation / display unit 18 Display screen 19 Operation button 21 Supply Steaming pipe 22 Steaming solenoid valve 23 Steaming motor valve 24 Boiler drain pipe 25 Boiler drain valve 26 Compressor 27 Door opening solenoid valve 28 Door tightening solenoid valve 31 Exhaust pipe 32 Vacuum motor valve 33 Exhaust motor valve 34 Supply pipe 35 Vacuum pump Water supply valve (air supply solenoid valve)

Claims (7)

  By passing water vapor in a highly saturated water vapor state where the vapor saturation does not fall below 100% via a pressure vessel containing a metal product to which foreign substances including organic matter are attached, the foreign substances are softened from the metal product. A distribution-type high-pressure steam cleaning method for metal products, comprising a high-pressure steam cleaning step for cleaning by a hydrothermal process. In claim 1,
Steam is supplied to the pressure vessel containing the metal product and the pressure vessel is heated by a heater from the outside to increase the internal temperature and the internal pressure of the pressure vessel to a predetermined temperature and pressure. Including a temperature raising and boosting step to
Next to the temperature raising / pressurizing step, the internal temperature and internal pressure of the pressure vessel are maintained at a predetermined cleaning temperature, a predetermined cleaning pressure, and a predetermined steam saturation, over the predetermined cleaning time. A distribution-type high-pressure steam cleaning method for metal products that performs a high-pressure steam cleaning process. In claim 2,
A flow-type high-pressure steam cleaning method for metal products, which includes an air exclusion step for removing air from the pressure vessel containing the metal products before the temperature raising and pressure-increasing step. In claim 2 or 3,
In the high-pressure steam cleaning step,
Supplying steam at a predetermined pressure and temperature from the upstream side of the water vapor flow direction to the pressure vessel at a predetermined flow rate through a steam supply valve maintained at a predetermined opening;
The opening of the exhaust valve is adjusted according to the internal pressure of the pressure vessel on the downstream side of the water vapor flow direction with respect to the pressure vessel, and the internal temperature of the pressure vessel and the internal pressure are respectively maintained at predetermined values. Flow-type high-pressure steam cleaning method for metal products to be controlled. In any one of claims 1 to 4,
The metal product to be cleaned is a flow-type high-pressure steam cleaning method for metal products to which foreign matters including fats and oils are attached. In claim 5,
The metal product is a flow-type high-pressure steam cleaning method for metal products which are aluminum products. In claim 6,
The fats and oils are cutting fluids,
In the high-pressure steam cleaning step, a flow-type high-pressure steam cleaning method for metal products that performs cleaning under any of the following conditions (1) to (3).
(1) In a state where the inside of the pressure vessel is maintained at a cleaning temperature of 105 ° C. or higher, water vapor that does not fall below 100% of the vapor saturation is circulated over a cleaning time of at least 20 minutes.
(2) In a state where the inside of the pressure vessel is maintained at a washing temperature of 120 ° C. or higher, water vapor that does not fall below 100% of the vapor saturation is circulated over a washing time of at least 5 minutes.
(3) In a state where the inside of the pressure vessel is maintained at a washing temperature of 115 ° C. or higher, water vapor that does not fall below 100% of the vapor saturation is circulated over a washing time of at least 10 minutes.