Method for removing hydrogen peroxide

Abstract

This method for removing hydrogen peroxide remaining in an object includes a decompression step (SB15) for decompressing an internal space of a chamber (11) in which the object is accommodated, a water vapor supply step (SB16) for supplying water vapor to the internal space in a state in which the internal space is decompressed, and an atmosphere supply step (SB17) for supplying the atmosphere to the internal space after the water vapor is supplied to the internal space.

Description

How to remove hydrogen peroxide

[0001] This application claims priority to Japanese Patent Application No. 2023-182110 filed in Japan on October 23, 2023, and Japanese Patent Application No. 2023-186270 filed in Japan on October 31, 2023, the contents of which are incorporated herein by reference. The technology disclosed in this specification relates to a method for removing hydrogen peroxide.

[0002] In the technical field of sterilization devices, a sterilization device using hydrogen peroxide is known, as disclosed in Patent Document 1.

[0003] International Publication No. 2020 / 183696

[0004] There is a need for a technique for removing hydrogen peroxide remaining on an object after the object has been sterilized with hydrogen peroxide.

[0005] The technology disclosed in this specification aims to remove hydrogen peroxide remaining on an object.

[0006] This specification discloses a method for removing hydrogen peroxide remaining in an object, which includes a depressurizing step of depressurizing the internal space of a chamber containing the object, a water vapor supplying step of supplying water vapor into the internal space while the internal space is depressurized, and an air supplying step of supplying air into the internal space after the water vapor has been supplied into the internal space.

[0007] According to the technology disclosed in this specification, hydrogen peroxide remaining on an object is removed.

[0008] Fig. 1 is a schematic diagram of a sterilization apparatus according to a first embodiment. Fig. 2 is a flowchart showing the operation of the sterilization apparatus according to the first embodiment. Fig. 3 is a flowchart showing the removal process according to the first embodiment. Fig. 4 is a diagram showing the fluctuation of the amount of hydrogen peroxide remaining on a 96-well plate due to the reduced pressure drying process. Fig. 5 is a diagram for explaining the effect of the removal process according to the first embodiment. Fig. 6 is a flowchart showing the removal process according to a second embodiment.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the embodiments. The components of the embodiments described below can be combined as appropriate. In addition, some components may not be used.

[0010] First Embodiment The first embodiment will be described.

[0011] <Sterilization Apparatus> Fig. 1 is a diagram showing a schematic diagram of a sterilization apparatus 100 according to this embodiment. The sterilization apparatus 100 uses hydrogen peroxide gas (H ２ O ２ ) to sterilize the object. Examples of the object include parts used in cell culture. Examples of the parts include petri dishes and well plates. The object may also be a medical instrument. Examples of the medical instrument include steel products such as forceps, scissors, or shears, and resin products such as tubes.

[0012] The sterilization apparatus 100 comprises a chamber unit 10 , a hydrogen peroxide supply unit 20 , a steam cleaning unit 30 , a decompression unit 40 , a pressure recovery unit 50 , and a control unit 60 .

[0013] The chamber unit 10 includes a chamber 11 including a door 12 , a heating unit 13 , a pressure sensor 14 , and a temperature sensor 15 .

[0014] The chamber 11 accommodates an object. The chamber 11 has an internal space in which the object is placed. The door 12 opens and closes an opening provided in the chamber 11. The object is carried into the internal space of the chamber 11 through the opening of the chamber 11. When the door 12 is closed, the internal space of the chamber 11 is sealed.

[0015] The heating unit 13 is connected to the chamber 11. The heating unit 13 adjusts the temperature of the internal space of the chamber 11.

[0016] The pressure sensor 14 is connected to the chamber 11. The pressure sensor 14 detects the pressure in the internal space of the chamber 11.

[0017] The temperature sensor 15 is connected to the chamber 11. The temperature sensor 15 detects the temperature of the internal space of the chamber 11.

[0018] During sterilization of an object, hydrogen peroxide supply unit 20 supplies hydrogen peroxide gas to the interior space of chamber 11. Hydrogen peroxide supply unit 20 includes bottle 21, extraction line 22, tube pump 23, storage unit 24, filter 25, evaporator 26, supply line 27, valve 28, and heater 29.

[0019] Bottle 21 contains an aqueous solution of hydrogen peroxide.

[0020] The extraction line 22 connects the bottle 21 to the storage unit 24. The aqueous solution of hydrogen peroxide extracted from the bottle 21 is supplied to the storage unit 24 via the extraction line 22.

[0021] A tube pump 23 is disposed in the extraction line 22. The tube pump 23 operates to supply the aqueous solution of hydrogen peroxide from the bottle 21 to the reservoir 24.

[0022] The storage unit 24 temporarily stores a predetermined amount of aqueous hydrogen peroxide solution extracted from the bottle 21. The air (atmospheric air) surrounding the storage unit 24 is introduced into the storage unit 24 via a filter 25. The pressure in the storage unit 24 is atmospheric pressure. An example of the filter 25 is a HEPA filter.

[0023] The vaporizer 26 is connected to the storage unit 24 via a supply line 27. The vaporizer 26 vaporizes the aqueous solution of hydrogen peroxide supplied from the storage unit 24 to produce hydrogen peroxide gas.

[0024] Valve 28 is disposed on supply line 27. An example of valve 28 is a solenoid valve. When valve 28 opens, the aqueous hydrogen peroxide solution in storage unit 24 is sucked into depressurized evaporator 26. As described above, the air (atmosphere) surrounding storage unit 24 is introduced into storage unit 24 via filter 25. When valve 28 opens, air (atmosphere) is sucked into evaporator 26 together with the aqueous hydrogen peroxide solution.

[0025] Vaporizer 26 is connected to chamber 11 via injection line 16 and injection line 17. Valve 71 is disposed in injection line 16, and valve 72 is disposed in injection line 17. Electromagnetic valves are exemplified as valves 71 and 72. Hydrogen peroxide gas is generated in vaporizer 26, and when the pressure in vaporizer 26 increases, valve 71 or valve 72 opens, supplying the hydrogen peroxide gas into the internal space of chamber 11.

[0026] The heater 29 adjusts the temperature of the evaporator 26. The heater 29 maintains the evaporator 26 at a predetermined temperature.

[0027] The steam cleaning unit 30 supplies water vapor to the interior space of the chamber 11 in a hydrogen peroxide removal process carried out after a sterilization process. The steam cleaning unit 30 includes a bottle 31, an extraction line 32, a tube pump 33, a storage unit 34, a filter 35, an evaporator 36, a supply line 37, a valve 38, and a heater 39.

[0028] The bottle 31 contains water.

[0029] The extraction line 32 connects the bottle 31 to the storage unit 34. The water extracted from the bottle 31 is supplied to the storage unit 34 via the extraction line 32.

[0030] A tube pump 33 is disposed in the extraction line 32. The tube pump 33 operates to pump water from the bottle 31 to the reservoir .

[0031] The storage unit 34 temporarily stores a predetermined amount of water extracted from the bottle 31. The air (atmospheric air) surrounding the storage unit 34 is introduced into the storage unit 34 via a filter 35. The pressure in the storage unit 34 is atmospheric pressure. An example of the filter 35 is a HEPA filter.

[0032] The evaporator 36 is connected to the storage unit 34 via a supply line 37. The evaporator 36 evaporates the water supplied from the storage unit 34 to generate water vapor.

[0033] Valve 38 is disposed on supply line 37. An example of valve 38 is a solenoid valve. When valve 38 is opened, water in storage unit 34 is sucked into depressurized evaporator 36. As described above, air (atmosphere) surrounding storage unit 34 is introduced into storage unit 34 via filter 35. When valve 38 is opened, air (atmosphere) is sucked into evaporator 36 together with water.

[0034] The evaporator 36 is connected to the chamber 11 via an injection line 18 and an injection line 19. A valve 73 is disposed in the injection line 18, and a valve 74 is disposed in the injection line 19. An example of the valves 73 and 74 is a solenoid valve. When water vapor is generated in the evaporator 36 and the pressure in the evaporator 36 increases, the valve 73 or 74 opens, and the water vapor is supplied to the internal space of the chamber 11.

[0035] The heater 39 adjusts the temperature of the evaporator 36. The heater 39 maintains the evaporator 36 at a predetermined temperature.

[0036] The decompression unit 40 exhausts gas from the internal space of the chamber 11. The decompression unit 40 reduces the pressure in the internal space of the chamber 11 by exhausting gas from the internal space of the chamber 11. The decompression unit 40 includes a vacuum pump 41, a first catalyst tank 42, a second catalyst tank 43, a first heater 44, and a second heater 45.

[0037] The vacuum pump 41 is connected to the chamber 11 via an exhaust line 46. The vacuum pump 41 operates to exhaust gas from the internal space of the chamber 11. A valve 77 is disposed in the exhaust line 46. When the pressure in the internal space of the chamber 11 is to be reduced, the valve 77 is closed and the vacuum pump 41 is stopped when the pressure in the internal space of the chamber 11 reaches a predetermined value.

[0038] The first catalyst tank 42 is disposed upstream of the vacuum pump 41. The second catalyst tank 43 is disposed downstream of the vacuum pump 41. The catalyst contains, for example, manganese dioxide as its main component and decomposes hydrogen peroxide.

[0039] The first heater 44 keeps the first catalyst tank 42 warm, and the second heater 45 keeps the second catalyst tank 43 warm.

[0040] The pressure-recovery unit 50 recovers the pressure in the internal space of the chamber 11 that has been reduced in pressure by the decompression unit 40. The pressure-recovery unit 50 introduces air (atmospheric air) from the external space of the chamber 11 into the internal space of the chamber 11 to recover the pressure in the internal space of the chamber 11. The pressure-recovery unit 50 includes a filter 51 and an introduction line 52.

[0041] The filter 51 collects foreign matter from the air (atmospheric air) introduced into the internal space of the chamber 11. An example of the filter 51 is a HEPA filter.

[0042] The introduction line 52 connects the internal space and the external space of the chamber 11. Air (atmosphere) introduced from the external space of the chamber 11 into the internal space of the chamber 11 flows through the introduction line 52. The air (atmosphere) in the external space of the chamber 11 is introduced into the internal space of the chamber 11 via the filter 51.

[0043] A valve 78 is disposed in the introduction line 52. An example of the valve 78 is a solenoid valve. The valve 78 adjusts the flow rate of air in the introduction line 52. When the valve 78 is opened, air (atmosphere) in the space outside the chamber 11 is introduced into the internal space of the chamber 11 via the introduction line 52. When the valve 78 is closed, the introduction of air (atmosphere) into the internal space of the chamber 11 is stopped.

[0044] The control unit 60 controls the components of the sterilization apparatus 100. The control unit 60 has a control device 61 and an input device 62. The control device 61 includes a computer system. Examples of the input device 62 include a touch panel or a computer keyboard. The control device 61 can control the components of the sterilization apparatus 100 based on input data input via the input device 62, for example.

[0045] <Operation of Sterilization Apparatus> Figure 2 is a flowchart showing the operation of the sterilization apparatus 100 according to this embodiment. In this embodiment, the sterilization apparatus 100 carries out a sterilization process SA and a removal process SB. The removal process SB is carried out after the sterilization process SA. The removal process SB is a process for removing hydrogen peroxide remaining on the object after the sterilization process SB.

[0046] (Sterilization Treatment) When an object is to be sterilized, the object is placed inside the chamber 11. A user of the sterilization apparatus 100 carries the object into the internal space of the chamber 11 through the opening of the chamber 11. After the object has been placed in the internal space of the chamber 11, the user closes the door 12. When the door 12 is closed, the internal space of the chamber 11 is sealed.

[0047] After the internal space of chamber 11 is sealed, control device 61 controls decompression unit 40 to exhaust gas from the internal space of chamber 11. After the gas has been exhausted from the internal space of chamber 11, control device 61 controls hydrogen peroxide supply unit 20 to supply hydrogen peroxide gas into the internal space of chamber 11. Control device 61 controls heating unit 13 to heat the internal space of chamber 11 to a predetermined sterilization temperature. With the internal space of chamber 11 heated to the sterilization temperature, hydrogen peroxide gas is supplied into the internal space of chamber 11. As an example, the sterilization temperature is approximately 50°C. By supplying hydrogen peroxide gas into the internal space of chamber 11, the hydrogen peroxide gas comes into contact with the surface of the object, and the object is sterilized with hydrogen peroxide.

[0048] (Removal Process) After the sterilization process is completed, a removal process SB is carried out to remove hydrogen peroxide remaining in the object. Figure 3 is a flowchart showing the removal process SB according to this embodiment. In this embodiment, the removal process SB includes a reduced pressure drying step SB11, a water vapor supplying step SB12, an atmosphere supplying step SB13, an atmosphere holding step SB14, a reduced pressure step SB15, a water vapor supplying step SB16, an atmosphere supplying step SB17, and an atmosphere holding step SB18.

[0049] After the sterilization process is completed, a reduced-pressure drying step SB11 is performed with the object housed in the chamber 11. In the reduced-pressure drying step SB11, the control device 61 controls the decompression unit 40 to reduce the pressure in the internal space of the chamber 11 housing the object. In the reduced-pressure drying step SB11, the control device 61 reduces the pressure in the internal space of the chamber 11 to approximately 10 Pa (second pressure). In the reduced-pressure drying step SB11, the control device 61 controls the heating unit 13 to raise the temperature of the internal space of the chamber 11 to a reduced-pressure drying temperature that is higher than the sterilization temperature. As an example, the reduced-pressure drying temperature is approximately 80°C.

[0050] In the reduced pressure drying step SB11, the pressure in the internal space of the chamber 11 is adjusted to about 10 Pa, and the temperature is maintained at about 80° C. for about 24 hours (second time).

[0051] In the reduced pressure drying step SB11, when the internal space of the chamber 11 is decompressed, the hydrogen peroxide remaining in the object evaporates efficiently, and the hydrogen peroxide is removed from the object. However, after a certain time has passed since the start of the reduced pressure drying step SB11, the amount of evaporated hydrogen peroxide decreases.

[0052] Figure 4 shows the change in the amount of hydrogen peroxide remaining on a 96-well plate due to the vacuum drying step SB11. As shown in Figure 4, the amount of hydrogen peroxide remaining on a sterilized 96-well plate decreases quadratically during the vacuum drying step, but it has been found that the removal effect is limited to a concentration of approximately 1.0 μg / mL at the time of filling with culture medium. Therefore, in this embodiment, the control device 61 terminates the vacuum drying step SB11 approximately 24 hours after the start of the vacuum drying step SB11. Possible causes of a decrease in the amount of evaporated hydrogen peroxide include a high concentration of hydrogen peroxide remaining in the object or hydrogen peroxide binding to the object, making it difficult to evaporate.

[0053] After the reduced-pressure drying step SB11 is completed, a water vapor supplying step SB12 is performed. In the water vapor supplying step SB12, the control device 61 controls the steam cleaning unit 30 so that water vapor is supplied to the internal space of the chamber 11 while the internal space of the chamber 11 is depressurized to approximately 10 Pa.

[0054] In the water vapor supplying step SB12, water vapor is supplied to the internal space of the chamber 11.

[0055] The amount of water vapor supplied to the internal space of the chamber 11 is small. As an example, the amount of water vapor supplied to the internal space of the chamber 11 is approximately 10 cc. If a large amount of water vapor is supplied to the internal space of the chamber 11, the vacuum pump 41 of the decompression unit 40 may suck in a large amount of water vapor in the decompression step SB15 performed after the water vapor supply step SB12. In this embodiment, the amount of water vapor supplied to the internal space of the chamber 11 is determined in advance. The amount of water vapor supplied to the internal space of the chamber 11 is determined so as not to affect the vacuum pump 41 and so as to remove hydrogen peroxide from the target object.

[0056] Furthermore, by supplying a small amount of water vapor into the internal space of the chamber 11, the pressure in the internal space of the chamber 11 increases to approximately 20 Pa.

[0057] After the water vapor supply step SB12 is completed, the atmospheric air supply step SB13 is performed. In the atmospheric air supply step SB13, the control device 61 controls the pressure recovery unit 50 to supply atmospheric air to the internal space of the chamber 11. As described above, the pressure recovery unit 50 has a filter 51 such as a HEPA filter. Clean air (atmospheric air) that has passed through the filter 51 is supplied to the internal space of the chamber 11. The supply of air (atmospheric air) to the internal space of the chamber 11 increases the pressure in the internal space of the chamber 11. The control device 61 may increase the pressure in the internal space of the chamber 11 to atmospheric pressure or to a pressure lower than atmospheric pressure.

[0058] In this embodiment, in the atmosphere supplying step SB13, the pressure in the internal space of the chamber 11 increases to a pressure (approximately 90,000 Pa) lower than atmospheric pressure, so that the supplied water vapor is diffused over the entire surface of the object.

[0059] After the atmospheric pressure supply step SB13 is completed, an atmospheric pressure holding step SB14 is performed in which the pressure in the internal space of the chamber 11 is maintained at approximately 90,000 Pa. This causes the hydrogen peroxide remaining on the object to dissolve in the moisture (supplied water vapor) adhering to the entire surface of the object.

[0060] After the atmospheric holding step SB14 is completed, the depressurization step SB15 is carried out. In the depressurization step SB15, the control device 61 controls the depressurization unit 40 so that the internal space of the chamber 11 containing the object is depressurized. In the depressurization step SB15, the control device 61 depressurizes the internal space of the chamber 11 so that the pressure in the internal space of the chamber 11 becomes approximately 35 Pa (first pressure). In the depressurization step SB15, the control device 61 controls the heating unit 13 so that the depressurization temperature becomes equal to the temperature of the internal space of the chamber 11. As an example, the depressurization temperature is approximately 50°C. As the chamber 11 is depressurized, hydrogen peroxide remaining on the surface of the object is removed together with moisture and discharged to the external space.

[0061] In the depressurization step SB15, the pressure in the internal space of the chamber 11 is adjusted to about 35 Pa and the temperature is adjusted to about 50° C., and this state is maintained for a time period (first time) of 1 minute to 10 minutes. As an example, the state in which the pressure in the internal space of the chamber 11 is adjusted to about 35 Pa and the temperature is adjusted to about 50° C. is continued for about 3 minutes.

[0062] After the pressure reduction step SB15 is completed, the steam supplying step SB16 is carried out. The steam supplying step SB16 is the same as the steam supplying step SB12 described above.

[0063] After the water vapor supplying step SB16 is completed, the atmosphere supplying step SB17 and the atmosphere holding step SB18 are performed. The atmosphere supplying step SB17 is the same as the atmosphere supplying step SB13 described above, and the atmosphere holding step SB18 is the same as the atmosphere holding step SB14 described above.

[0064] The pulse process including the pressure reduction step SB15, the water vapor supply step SB16, the atmosphere supply step SB17, and the atmosphere holding step SB18 is performed multiple times. In the following description, the number of times the pulse process including the pressure reduction step SB15, the water vapor supply step SB16, the atmosphere supply step SB17, and the atmosphere holding step SB18 is performed is appropriately referred to as the pulse number.

[0065] The number of pulses is a predetermined value. The user may operate the input device 62 to input the number of pulses to the control device 61. The number of pulses may be determined arbitrarily by the user. The control device 61 determines whether the number of times the pulse process has been performed has reached the number of pulses (step SB19).

[0066] If it is determined in step SB19 that the number of pulses has not been reached (step SB19: No), the control device 61 repeats the processes from step SB15 to step SB18 until the number of pulse processes reaches the number of pulses.

[0067] If it is determined in step SB19 that the number of pulses has been reached (step SB19: Yes), the control device 61 ends the removal process SB.

[0068] <Effects> As described above, in this embodiment, the process SB for removing hydrogen peroxide remaining in the object includes a decompression step SB15 for decompressing the internal space of chamber 11 in which the object is housed, a water vapor supply step SB16 for supplying water vapor into the internal space of chamber 11 while the internal space of chamber 11 is decompressed, and an atmosphere supply step SB17 for supplying atmosphere into the internal space of chamber 11 after water vapor has been supplied to the internal space of chamber 11.

[0069] According to the embodiment, since the water vapor supplying step SB16 is performed, the hydrogen peroxide remaining on the object dissolves in the water vapor and is removed from the object, thereby sufficiently removing the hydrogen peroxide remaining on the object.

[0070] For example, in the field of regenerative medicine, cell culture is performed in a cell culture isolator. Components such as petri dishes and well plates are used in cell culture. The components used for cell culture are sterilized in a sterilization device 100 before being used in the cell culture isolator. If hydrogen peroxide remains in the components, cell culture will not be performed properly. According to this embodiment, the amount of residual hydrogen peroxide in the object is reduced to a concentration of less than 0.5 μg / mL when the medium is filled, allowing cell culture to be performed properly.

[0071] FIG. 5 is a diagram illustrating the effect of the removal treatment according to this embodiment. FIG. 5a shows the viability of human iPS cells cultured for 7 days on a 96-well plate that had been subjected to removal treatment after sterilization according to this embodiment. In FIG. 5a, Normal is the negative control, and A, C, E, and G represent plate rows. As shown in FIG. 5a, no effect of residual hydrogen peroxide was observed, including in rows A and G on the outer sides of the plate where hydrogen peroxide is likely to remain, and the viability was equivalent to that of the negative control group. FIG. 5b shows the cell counts after 1 day, 3 days, and 5 days when marmoset ES cells were cultured on a 6-well plate. In FIG. 5b, Control is the negative control, and Sample is the test group. As shown in FIG. 5b, no significant difference was observed between the negative control and the test group, regardless of the culture period, and no effect of residual hydrogen peroxide was observed.

[0072] In this embodiment, the pulse process including the decompression process SB15, the water vapor supply process SB16, and the air supply process SB17 is performed multiple times. By performing the pulse process multiple times, hydrogen peroxide remaining in the object is sufficiently removed.

[0073] In this embodiment, the pressure reduction step SB15 reduces the pressure in the internal space of the chamber 11 to a first pressure (approximately 35 Pa). Prior to the pulse step (pressure reduction step SB15), a reduced-pressure drying step SB11 is performed in which the pressure in the internal space of the chamber 11 is reduced to a second pressure (approximately 10 Pa) lower than the first pressure. This efficiently evaporates any hydrogen peroxide remaining in the object, thereby removing the hydrogen peroxide from the object.

[0074] In this embodiment, in the depressurization step SB15, the internal space of chamber 11 is maintained at a first pressure (approximately 35 Pa) for a first time (e.g., 3 minutes). In the reduced-pressure drying step SB11, the internal space of chamber 11 is maintained at a second pressure (approximately 10 Pa) for a second time (e.g., 24 hours) that is longer than the first time. As a result, hydrogen peroxide remaining in the object is efficiently evaporated in the reduced-pressure drying step SB11, and the hydrogen peroxide is removed from the object.

[0075] In this embodiment, before the reduced pressure drying process SB11, a sterilization process (sterilization treatment SA) is performed in which the object is sterilized with hydrogen peroxide in the internal space of chamber 11. In this way, the sterilization treatment SA and the removal treatment SB are carried out consecutively in one sterilization apparatus 100.

[0076] Second Embodiment A second embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0077] 6 is a flowchart showing the removal process SB according to this embodiment. In this embodiment, the removal process SB includes a reduced pressure drying step SB21, an atmosphere supplying step SB22, a reduced pressure step SB23, a water vapor supplying step SB24, and an atmosphere supplying step SB25.

[0078] After the sterilization process is completed, a reduced-pressure drying step SB21 is performed with the object housed in the chamber 11. In the reduced-pressure drying step SB21, the control device 61 controls the decompression unit 40 to reduce the pressure in the internal space of the chamber 11 housing the object. In the reduced-pressure drying step SB21, the control device 61 reduces the pressure in the internal space of the chamber 11 to approximately 10 Pa (second pressure). In the reduced-pressure drying step SB21, the control device 61 controls the heating unit 13 to raise the temperature of the internal space of the chamber 11 to a reduced-pressure drying temperature that is higher than the sterilization temperature. As an example, the reduced-pressure drying temperature is approximately 80°C.

[0079] In the reduced pressure drying step SB21, the pressure in the internal space of the chamber 11 is adjusted to about 10 Pa, and the temperature is maintained at about 80° C. for about 24 hours (second time).

[0080] In the reduced-pressure drying step SB21, when the internal space of the chamber 11 is depressurized, the hydrogen peroxide remaining in the object evaporates efficiently, thereby removing the hydrogen peroxide from the object. However, the amount of evaporated hydrogen peroxide decreases after a certain time has passed since the start of the reduced-pressure drying step SB21. Therefore, in this embodiment, the control device 61 terminates the reduced-pressure drying step SB21 approximately 24 hours after the start of the reduced-pressure drying step SB21. Note that possible causes of the decrease in the amount of evaporated hydrogen peroxide include a high concentration of hydrogen peroxide remaining in the object or hydrogen peroxide binding to the object, making it difficult to evaporate.

[0081] After the reduced pressure drying step SB21 is completed, the atmospheric air supply step SB22 is performed. In the atmospheric air supply step SB22, the control device 61 controls the pressure recovery unit 50 to supply atmospheric air to the internal space of the chamber 11. As described above, the pressure recovery unit 50 has a filter 51 such as a HEPA filter. Clean air (atmospheric air) that has passed through the filter 51 is supplied to the internal space of the chamber 11. The supply of air (atmospheric air) to the internal space of the chamber 11 increases the pressure in the internal space of the chamber 11. The control device 61 may increase the pressure in the internal space of the chamber 11 to atmospheric pressure or to a pressure lower than atmospheric pressure.

[0082] In this embodiment, in the atmosphere supply step SB22, the pressure in the internal space of the chamber 11 rises to a pressure (approximately 90,000 Pa) lower than atmospheric pressure, so that hydrogen peroxide remaining in the object is discharged to the external space of the chamber 11 together with the atmosphere.

[0083] After the air supply step SB22 is completed, a depressurization step SB23 is carried out to depressurize the internal space of the chamber 11.

[0084] After the pressure reduction step SB23 is completed, a water vapor supply step SB24 is performed to supply water vapor into the internal space of the chamber 11. When water vapor is supplied into the internal space of the chamber 11 in the water vapor supply step SB24, hydrogen peroxide remaining in the object dissolves in the water vapor. The water vapor pulls the hydrogen peroxide away from the object. This removes the hydrogen peroxide from the object.

[0085] After the water vapor supply step SB24 is completed, an atmosphere supply step SB25 is performed. In the atmosphere supply step SB25, the control device 61 controls the pressure recovery unit 50 so that the atmosphere is supplied to the internal space of the chamber 11.

[0086] The pulse process, which includes the pressure reduction step SB23, the steam supply step SB24, and the atmosphere supply step SB25, is performed multiple times. The pulse count, which indicates the number of times the pulse process is performed, is a predetermined value. The user may operate the input device 62 to input the pulse count into the control device 61. The pulse count may be arbitrarily determined by the user. The control device 61 determines whether the number of times the pulse process has been performed has reached the pulse count (step SB26).

[0087] If it is determined in step SB26 that the number of pulses has not been reached (step SB26: No), the control device 61 repeats the processes of steps SB23 to SB25 until the number of pulse processes reaches the number of pulses.

[0088] If it is determined in step SB26 that the number of pulses has been reached (step SB26: Yes), the control device 61 ends the removal process SB.

[0089] 10...chamber unit, 11...chamber, 12...door, 13...heating unit, 14...pressure sensor, 15...temperature sensor, 16...injection line, 17...injection line, 18...injection line, 19...injection line, 20...hydrogen peroxide supply unit, 21...bottle, 22...extraction line, 23...tube pump, 24...storage unit, 25...filter, 26...evaporator, 27...supply line, 28...valve, 29...heater, 30...steam cleaning unit, 31...bottle, 32...extraction line, 33...tube pump, 34...storage unit, 35...filter, 36...evaporator, 37...supply line, 38...valve, 39...heater, 40...decompression unit , 41...vacuum pump, 42...first catalyst tank, 43...second catalyst tank, 44...first heater, 45...second heater, 46...exhaust line, 50...repressurization unit, 51...filter, 52...inlet line, 60...control unit, 61...control device, 62...input device, 71...valve, 72...valve, 73...valve, 74...valve, 77...valve, 78...valve, 100...sterilization apparatus, SA...sterilization treatment, SB...removal treatment, SB11...reduced pressure drying process, SB12...water vapor supply process, SB13...atmosphere supply process, SB14...atmosphere holding process, SB15...reduced pressure process, SB16...water vapor supply process, SB17...atmosphere supply process, SB18...atmosphere holding process.

Claims

1. A method for removing hydrogen peroxide remaining in an object, comprising: a decompression process for decompressing an internal space of a chamber in which the object is housed; a water vapor supply process for supplying water vapor to the internal space while the internal space is in a decompressed state; and an air supply process for supplying clean air that has been passed through a HEPA filter to the internal space after the water vapor has been supplied to the internal space.

2. The method for removing hydrogen peroxide according to claim 1, wherein a pulse process including the pressure reducing process, the water vapor supply process, and the air supply process is carried out a plurality of times.

3. The method for removing hydrogen peroxide according to claim 2, wherein the internal space is brought to a first pressure by the depressurization process, and a depressurization drying process is carried out before the pulse process in order to depressurize the internal space to a second pressure lower than the first pressure.

4. The method for removing hydrogen peroxide according to claim 3, wherein in the decompression step, the state in which the internal space is at the first pressure is maintained for a first time, and in the reduced-pressure drying step, the state in which the internal space is at the second pressure is maintained for a second time that is longer than the first time.

5. The method for removing hydrogen peroxide according to claim 3, wherein a sterilization step of sterilizing the object in the internal space with the hydrogen peroxide is carried out before the reduced pressure drying step.

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