Decontamination method and decontamination device using chlorine dioxide gas

Abstract

To provide a decontamination method and a decontamination device by chlorine dioxide gas which maintain the inside of a closed space as a decontamination object to sufficient low humidity environment during decontamination, can suppress corrosion in the space, are excellent in safety, and can complete decontamination work in short time.SOLUTION: A decontamination device A has a device body 1, a concentration measurement mechanism 2, a dehumidification and recovery mechanism 3, and a gas generation mechanism 4. The dehumidification and recovery mechanism 3 has a recovery cartridge part 30, and a line blower 31. The recovery cartridge part 30 is formed with two layers of an upper layer part 300 filled with activated charcoal, and a lower layer part 301 filled with crystalline zeolite. The gas generation mechanism 4 has a dehumidification cartridge 43. The dehumidification cartridge 43 is a member for passing gas for supply which is generated in an aeration tank 40 and is composed of chlorine dioxide gas and water vapor, capturing and dehumidifying the water vapor, and supplying only the chlorine dioxide gas to the inside of a sealed space S.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a decontamination method and decontamination device using chlorine dioxide gas, and more particularly to a decontamination method and decontamination device using chlorine dioxide gas that can maintain a sufficiently low humidity environment in an enclosed space to be decontaminated during decontamination, suppress corrosion in the space, and is safe and capable of completing decontamination work in a short time. [Background technology]

[0002] In recent years, there has been research into the use of chlorine dioxide gas as an antibacterial and antifungal decontamination method in sealed spaces such as safety cabinets and isolators for animal experiments, instead of formalin, which is a carcinogen.

[0003] Chlorine dioxide gas has been approved by the U.S. Environmental Protection Agency (EPA) as a sterilizing agent for fumigation since 1988. In addition, the method of sterilizing the inside of biosafety cabinets, where environmental disinfection and aseptic processing are required, with chlorine dioxide gas has been standardized by the American National Standards Institute (ANSI).

[0004] In addition, when decontaminating a sealed space using chlorine dioxide gas, if the contents within the space, for example, the components that form the sealed space, are made of iron, aluminum, copper, or other metal components, it is necessary to maintain the sealed space in a low humidity environment to prevent corrosion of these contents.

[0005] In this context, a decontamination method has been proposed that attempts to decontaminate large spaces safely and in a shorter time than conventional methods, without corroding the contents of the space requiring decontamination (see, for example, Patent Document 1).

[0006] In the decontamination method described in Patent Document 1, the amount of water vapor is 10 g / m 3The method described includes the steps of generating chlorine dioxide gas in an enclosed space under an environment of 31% or less relative humidity and introducing chlorine dioxide gas into the enclosed space at a chlorine dioxide gas concentration of 230 ppm or less and a CT value of 50 to 2000 ppm·h.

[0007] In addition, in Patent Document 1, even when the relative humidity in the enclosed space is low, the amount of water vapor is 10 g / m 3 When this occurs, there is a high risk of corrosion occurring, particularly for materials that have not been surface-treated, such as iron, aluminum, and copper, and it is stated that the indoor control based on relative humidity, which has traditionally been carried out during decontamination, is insufficient to prevent corrosion of the contents.

[0008] In addition, in Patent Document 1, the amount of water vapor in a closed space is set at 10 g / m 3 It is believed that the diffusion of chlorine dioxide gas is improved by setting the following. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 6637631 specification Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the decontamination method described in Patent Document 1, the amount of water vapor is 10 g / m 3 Although maintaining an environment of 30°C or less and a relative humidity of 31% or less is considered necessary to prevent corrosion of the contents in an enclosed space, it is actually difficult to maintain low levels of water vapor and relative humidity in an enclosed space.

[0011] More specifically, in the decontamination method described in Patent Document 1, no consideration is given at all to capturing the water vapor that is generated in conjunction with the generation of chlorine dioxide gas.

[0012] In the decontamination method described in Patent Document 1, chlorine dioxide water is aerated to liberate chlorine dioxide gas, which is then supplied to an enclosed space. During this process, water vapor volatilizes from the solution together with the chlorine dioxide gas.

[0013] This water vapor is supplied together with chlorine dioxide gas into the enclosed space to be decontaminated, so the humidity in the space easily increases. In other words, when the supply of chlorine dioxide gas starts in the enclosed space, the desired low humidity condition cannot be maintained.

[0014] Therefore, in the decontamination method described in Patent Document 1, even if a predetermined low humidity environment is created before chlorine dioxide gas is supplied into the sealed space, the amount of water vapor and the relative humidity increase after the supply of chlorine dioxide gas begins, making it impossible to prevent corrosion of the contents in the sealed space and perform decontamination.

[0015] In addition, conventional decontamination methods using chlorine dioxide gas, including the decontamination method described in Patent Document 1, were insufficient in terms of recovering chlorine dioxide gas in a short period of time and making the enclosed space usable, and there was room for improvement.

[0016] The present invention has been devised in consideration of the above points, and has an object to provide a decontamination method and decontamination apparatus using chlorine dioxide gas that can maintain a sufficiently low humidity environment inside an enclosed space to be decontaminated during decontamination, thereby suppressing corrosion within the space, and is safe and capable of completing decontamination work in a short period of time. [Means for solving the problem]

[0017] In order to achieve the above object, the present invention provides a decontamination method using chlorine dioxide gas, which reduces a predetermined microorganism in an enclosed space by applying chlorine dioxide gas into the space, and comprises sucking and dehumidifying the air in the enclosed space, and returning the dehumidified air to the enclosed space to maintain a relative humidity of less than 32% and an absolute humidity of less than 10 g / m. 3the supply gas containing chlorine dioxide gas and water vapor is generated, and the supply gas is dehumidified before being supplied to the sealed space, and the chlorine dioxide gas is supplied into the sealed space; after the chlorine dioxide gas supply step, the supply of the chlorine dioxide gas to the sealed space is stopped and the chlorine dioxide gas is exposed to the sealed space; and after the exposure step, the air in the sealed space is sucked to recover the chlorine dioxide gas and the concentration of the chlorine dioxide gas in the sealed space is reduced to less than 0.1 ppm.

[0018] In the dehumidification step, the air in the sealed space is sucked in and dehumidified, and the dehumidified air is returned to the sealed space to maintain the relative humidity in the sealed space at less than 32% and the absolute humidity at less than 10 g / m 3 By making the environment below 100° C., the enclosed space to be decontaminated can be made into a low-humidity environment in which the contents are less likely to corrode. That is, for example, even if the inside of the enclosed space was in a high-humidity environment before decontamination, it is possible to lower the humidity inside the enclosed space before decontamination work and then proceed with the subsequent processing.

[0019] In addition, in the chlorine dioxide gas supplying step, a supply gas containing chlorine dioxide gas and water vapor is generated, and before being supplied to the sealed space, the supply gas is dehumidified and the chlorine dioxide gas is supplied into the sealed space, thereby preventing the water vapor generated at the same time as the chlorine dioxide gas is introduced into the sealed space together with the chlorine dioxide gas, which would cause an increase in humidity in the sealed space. This also makes it possible to maintain the low humidity environment created in the dehumidifying step when the chlorine dioxide gas is introduced.

[0020] In addition, in the exposure step, after the chlorine dioxide gas supply step, the supply of chlorine dioxide gas to the sealed space is stopped and the sealed space is exposed to chlorine dioxide gas, thereby decontaminating the inside of the sealed space with chlorine dioxide gas. That is, the chlorine dioxide gas acts on the sealed space to reduce the number of specific microorganisms in the sealed space.

[0021] In addition, in the recovery process, after the exposure process, the air in the sealed space is sucked in to recover the chlorine dioxide gas, and the concentration of the chlorine dioxide gas in the sealed space is reduced to less than 0.1 ppm, so that the concentration of the chlorine dioxide gas in the sealed space after decontamination can be reduced to a concentration that is safe for the human body, etc. In other words, the sealed space after decontamination can be made into a safe environment for workers, etc. to use. The concentration of chlorine dioxide gas, 0.1 ppm, is the permissible exposure concentration for inhalation of chlorine dioxide, 8-hour time-weighted average (PEL-TWA), set by the U.S. Occupational Safety and Health Administration (USOSHA) from the perspective of occupational safety and health.

[0022] In addition, in the chlorine dioxide gas supply process, when the supply gas is passed through crystalline zeolite capable of adsorbing substances with molecular diameters of less than 0.3 nm for dehumidification, the water molecules are adsorbed by the crystalline zeolite for dehumidification. That is, out of the water vapor generated together with the chlorine dioxide gas, only the water vapor is selectively captured by the crystalline zeolite, and it becomes possible to efficiently supply only the chlorine dioxide gas into the closed space.

[0023] In addition, in the dehumidification process, when the air in the sealed space is passed through crystalline zeolite to dehumidify, the water molecules contained in the air in the sealed space are adsorbed by the crystalline zeolite, making it possible to dehumidify the space. In other words, in the dehumidification process, the crystalline zeolite can selectively capture only the water molecules from the air in the sealed space, thereby dehumidifying the sealed space.

[0024] Furthermore, when chlorine dioxide gas is supplied to the sealed space at a concentration in the range of 250 ppm to 1500 ppm in the chlorine dioxide gas supply process, the sealed space can be decontaminated efficiently in a short time, and chlorine dioxide gas can be handled at a concentration that makes it easy to ensure safety.

[0025] Here, in the chlorine dioxide gas supplying process, if the chlorine dioxide gas is supplied to the closed space at a concentration of less than 250 ppm, when the closed space is exposed to the chlorine dioxide gas for decontamination, the chlorine dioxide gas concentration is low, the efficiency of decontamination is reduced, and the time required to complete decontamination is long. In addition, in the chlorine dioxide gas supplying process, if the chlorine dioxide gas is supplied to the closed space at a concentration of more than 1500 ppm, the risk of explosion increases, making it difficult to ensure safety.

[0026] In addition, in the exposure process, if the closed space is exposed to chlorine dioxide gas until the CT value reaches at least 1100 ppm·hr, the closed space can be sufficiently decontaminated.

[0027] In addition, when the CT value of the chlorine dioxide gas in the sealed space reaches the target value in the exposure process and the recovery process is automatically started, the chlorine dioxide gas supplied to the sealed space can be efficiently recovered. As a result, the time from the start of preparation for decontamination to the completion of decontamination and the availability of the sealed space can be shortened.

[0028] In addition, during the chlorine dioxide gas supply process and exposure process, the relative humidity in the sealed space is kept below 32% and the absolute humidity is kept below 10 g / m 3 When the container is maintained in an environment below this level, the low humidity environment prepared in the dehumidification process before the start of decontamination can be maintained, thereby more sufficiently reducing the risk of corrosion of the contents.

[0029] In addition, in the chlorine dioxide gas supply process, when the gas in the sealed space is sucked and passed through activated carbon, and then used to generate supply gas, the sealed space can be prevented from becoming positive pressure, and chlorine dioxide gas can be prevented from leaking to the outside. That is, the gas containing chlorine dioxide gas supplied to the sealed space is collected, and the chlorine dioxide gas is adsorbed by activated carbon to produce fresh air, which is then used for aeration to generate supply gas. This makes it possible to circulate the gas by using the gas in the sealed space without introducing new air from the outside. Therefore, it is possible to avoid the phenomenon that the air pressure in the sealed space increases, the inside becomes positive pressure, and chlorine dioxide gas leaks to the outside through the gaps between the members that form the sealed space, as in the case of introducing new air from the outside in the generation of chlorine dioxide gas. In addition, since the gas is circulated, the concentration of chlorine dioxide gas can be efficiently increased in the sealed space. Furthermore, by adsorbing chlorine dioxide gas through activated carbon, the generation of rust in the air pump can be suppressed.

[0030] Furthermore, when the enclosed space is a safety cabinet or an isolator for animal breeding, the safety cabinet or the isolator for animal breeding can be decontaminated efficiently in a short time using chlorine dioxide gas, and the risk of corrosion of the contents can be reduced.

[0031] In order to achieve the above object, the decontamination apparatus of the present invention is a decontamination apparatus that reduces a predetermined microorganism in an enclosed space by applying chlorine dioxide gas phase to the space, and includes a decontamination apparatus main body connected via piping to a gas supply port and an exhaust port provided on the enclosed space side, a humidity measuring unit that measures the relative humidity and absolute humidity in the enclosed space, a gas concentration measuring unit that measures the chlorine dioxide gas concentration in the enclosed space, and a decontamination apparatus that dehumidifies air sucked from the enclosed space and maintains a relative humidity of less than 32% and an absolute humidity of less than 10 g / m within the enclosed space. 3the supply gas is generated through the piping path connected to the supply port and directed into the sealed space; a second dehumidification section provided on the piping path connected to the supply port and dehumidifying the supply gas; and a recovery section that sucks in the air in the sealed space that has been exposed to the chlorine dioxide gas for a certain period of time, recovers the chlorine dioxide gas, and reduces the concentration of the chlorine dioxide gas in the sealed space to less than 0.1 ppm.

[0032] Here, the decontamination apparatus main body is connected to the gas supply port and the gas exhaust port provided on the sealed space side via piping, so that the air in the sealed space can be directly supplied to the decontamination apparatus main body side and the air in the sealed space can be treated. This also makes it possible to decontaminate the sealed space without providing a separate device inside the sealed space.

[0033] In addition, the humidity measuring unit measures the relative humidity and absolute humidity in the sealed space, so that the relative humidity and absolute humidity in the sealed space when each process is being performed can be confirmed. Also, it becomes possible to carry out various operations according to the measured values ​​of the relative humidity and absolute humidity in the sealed space.

[0034] In addition, the gas concentration measuring unit measures the chlorine dioxide gas concentration in the sealed space, so that the carbon dioxide gas concentration in the sealed space during each treatment can be confirmed. Also, various operations can be performed according to the measured carbon dioxide gas concentration in the sealed space.

[0035] The first dehumidification unit dehumidifies the air sucked from the sealed space to maintain the relative humidity in the sealed space at less than 32% and the absolute humidity at less than 10 g / m 3By making the environment below 100° C., the sealed space to be decontaminated can be made into a low-humidity environment in which the contents are less likely to corrode. That is, for example, even if the inside of the sealed space was in a high-humidity environment before decontamination, the humidity inside the sealed space can be lowered via the first dehumidification unit before decontamination work, and the subsequent processing can be carried out.

[0036] In addition, chlorine dioxide gas can be produced for decontamination of enclosed spaces by mixing a chemical solution of chlorine dioxide gas in the aeration tank and sending gas into the aeration tank with an air pump.

[0037] In addition, an air pump sends gas into the aeration tank to generate a supply gas containing chlorine dioxide gas and water vapor, and sends the supply gas toward the sealed space through a piping path connected to the supply port, thereby allowing the chlorine dioxide gas generated in the aeration tank to be supplied toward the sealed space.

[0038] In addition, a second dehumidifying unit is provided on the piping path connected to the supply port, and by dehumidifying the supply gas, only the water vapor contained in the supply gas is removed and chlorine dioxide gas can be supplied into the sealed space. This makes it possible to prevent water vapor from being introduced into the sealed space together with chlorine dioxide gas, and to prevent the humidity in the sealed space from increasing. This also makes it possible to maintain the low-humidity environment of the sealed space through the first dehumidifying unit when chlorine dioxide gas is introduced.

[0039] In addition, the recovery unit sucks in the air in the sealed space that has been exposed to chlorine dioxide gas for a certain period of time, recovers the chlorine dioxide gas, and reduces the concentration of chlorine dioxide gas in the sealed space to less than 0.1 ppm, thereby making it possible to reduce the concentration of chlorine dioxide gas in the sealed space after decontamination to a concentration that is safe for the human body, etc. In other words, the sealed space after decontamination can be made into a safe environment for workers, etc. to use.

[0040] In addition, when the second dehumidifying section has crystalline zeolite capable of adsorbing substances with molecular diameters of less than 0.3 nm, the water molecules are adsorbed by the crystalline zeolite to dehumidify. That is, the water vapor generated together with chlorine dioxide gas is selectively captured by the crystalline zeolite, and only chlorine dioxide gas can be efficiently supplied into the sealed space.

[0041] Furthermore, when the first dehumidification unit has crystalline zeolite, the water molecules contained in the air in the sealed space can be adsorbed by the crystalline zeolite to dehumidify it. That is, the first dehumidification unit can also selectively capture only the water molecules from the air in the sealed space with the crystalline zeolite to dehumidify the sealed space.

[0042] In addition, when the recovery section has activated carbon, the chlorine dioxide gas used to decontaminate the enclosed space can be adsorbed onto the activated carbon, making it possible to efficiently reduce the concentration of chlorine dioxide gas in the enclosed space.

[0043] In addition, when a recovery cartridge part having a layer with a first dehumidifying part and a layer with a recovery part is provided, it is possible to perform each process of dehumidifying the air in the sealed space before decontamination and recovering chlorine dioxide gas from the air in the sealed space after the exposure to chlorine dioxide gas is completed through one recovery cartridge part. This makes it easier to make the decontamination device body compact by consolidating the members required for each operation into one. In addition, the first dehumidifying part and the recovery part can be replaced at the same time by simply replacing the recovery cartridge, making maintenance work easier.

[0044] In addition, when a sequencer is provided that automatically controls the operation of the aeration tank, air pump, air supply and exhaust system, and recovery unit based on the relative humidity and absolute humidity in the sealed space measured by the humidity measuring unit, or the concentration of chlorine dioxide gas measured by the gas concentration measuring unit, the aeration tank, air pump, air supply and exhaust system, and recovery unit can be automatically controlled through the sequencer according to the measured values ​​of the relative humidity and absolute humidity in the sealed space, or the concentration of chlorine dioxide gas in the sealed space. This makes it possible to automatically control a series of operations, such as dehumidifying the air in the sealed space before decontamination, starting up to increase the concentration of chlorine dioxide gas before starting decontamination, exposing the sealed space to chlorine dioxide gas, recovering chlorine dioxide gas after decontamination, and cleaning thereafter.

[0045] In addition, when the gas concentration measuring unit measures the concentration of chlorine dioxide gas by light absorption method and the measurement resolution is 0.001 ppm, the concentration of chlorine dioxide gas in the closed space can be measured with high accuracy. In addition, the concentration of chlorine dioxide gas can be measured in a short time, for example, once every 30 seconds or once every minute. According to this, when the concentration of chlorine dioxide gas in the closed space is made less than 0.1 ppm in the recovery unit, it is possible to detect with high accuracy whether the concentration falls below the standard concentration. In addition, it is possible to check the concentration change when chlorine dioxide gas is supplied into the closed space and the change in the CT value of chlorine dioxide gas during decontamination in almost real time. In addition, in the conventional method, a complicated task of repeatedly sampling and measuring using a gas detector tube for chlorine dioxide is required, but the gas concentration measuring unit of the present invention can automatically suck and accurately measure the concentration.

[0046] In addition, when the air pump is connected to the exhaust port and sucks the gas in the sealed space through a piping path provided with a gas purifier made of activated carbon, and sends the sucked gas to the aeration tank, it is possible to prevent the sealed space from becoming positive pressure, and prevent chlorine dioxide gas from leaking to the outside. That is, the gas containing chlorine dioxide gas supplied to the sealed space is collected, and the chlorine dioxide gas is adsorbed by the activated carbon to produce fresh air, which is then used for aeration to generate supply gas. This makes it possible to circulate the gas using the gas in the sealed space without introducing new air from the outside. Therefore, it is possible to avoid the phenomenon that the air pressure in the sealed space rises, the inside becomes positive pressure, and chlorine dioxide gas leaks to the outside through the gaps between the members that form the sealed space, as in the case of introducing new air from the outside in the generation of chlorine dioxide gas. In addition, since the gas is circulated, the concentration of chlorine dioxide gas can be efficiently increased in the sealed space. Furthermore, by adsorbing chlorine dioxide gas through activated carbon, it is possible to prevent rust from occurring in the air pump. Effect of the Invention

[0047] The decontamination method and decontamination apparatus using chlorine dioxide gas according to the present invention maintain a sufficiently low humidity environment within the enclosed space to be decontaminated during decontamination, thereby preventing corrosion within the space, and is also highly safe and capable of completing the decontamination work in a short period of time. [Brief description of the drawings]

[0048] [Figure 1] 1 is a schematic diagram showing a decontamination apparatus according to an embodiment of the present invention and a safety cabinet to be decontaminated. [Diagram 2] FIG. 1 is a flow chart showing the flow of a decontamination method to which the present invention is applied. [Diagram 3] 1A is a graph showing the change in chlorine dioxide gas concentration and relative humidity in Example 1, and FIG. 1B is a graph showing the change in chlorine dioxide gas concentration and relative humidity in Comparative Example. [Figure 4]13 is a graph showing the change in chlorine dioxide gas concentration and chlorine dioxide gas CT value over time in an enclosed space S in Example 2. [Diagram 5] 13 is a graph showing changes in temperature, absolute humidity, and relative humidity over time in the enclosed space S in Example 2. [Figure 6] FIG. 1 is a schematic diagram showing the configuration of an embodiment of a device for preventing positive pressure when chlorine dioxide gas is supplied to an enclosed space. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Hereinafter, embodiments of the present invention will be described with reference to the drawings for the purpose of understanding the present invention. [Embodiments of the present invention] As an example of a decontamination apparatus to which the present invention is applied, an embodiment of the present invention will be described. Note that the content described below is merely an example of a structure to which the present invention is applied, and the embodiment of the present invention is not limited to the structure described below.

[0050] As shown in Fig. 1, a decontamination apparatus A, which is an example of a decontamination apparatus to which the present invention is applied, is an apparatus for decontaminating a sealed space S of a safety cabinet B having the sealed space S. The sealed space S referred to here corresponds to the sealed space in the claims of the present application.

[0051] Safety cabinet B is a device that contains biohazards such as pathogens and genetically modified organisms to create a safe working environment, and is installed, for example, in the examination rooms of universities, research institutes, and medical institutions.

[0052] The safety cabinet B maintains the inside of the sealed space S at negative pressure, and the air in the sealed space is purified through a HEPA filter and exhausted to the outside from the exhaust port B1 (see Figure 1). 3 ~5m 3 It is designed to be spacious.

[0053] Here, the decontamination apparatus A has an apparatus main body 1, a concentration measuring mechanism 2, a dehumidification and recovery mechanism 3, and a gas generation mechanism 4, as shown in FIG.

[0054] The apparatus body 1 is a part that constitutes the main body of the decontamination apparatus A, and is also a housing member that houses the concentration measurement mechanism 2, the dehumidification and recovery mechanism 3, and the gas generation mechanism 4. The apparatus body 1 referred to here is a part that corresponds to the decontamination apparatus body in the claims of the present application.

[0055] The concentration measuring mechanism 2 is a measuring mechanism for measuring the relative humidity and absolute humidity of the internal environment of the sealed space S. The concentration measuring mechanism 2 also measures the temperature of the internal environment of the sealed space S in order to calculate the relative humidity and absolute humidity.

[0056] The dehumidification and recovery mechanism 3 is a mechanism for dehumidifying the air inside the sealed space S before decontaminating the sealed space S. The dehumidification and recovery mechanism 3 is also a mechanism for recovering chlorine dioxide gas from the air inside the sealed space S after exposing the sealed space S to chlorine dioxide gas.

[0057] The gas production mechanism 4 is a mechanism for producing chlorine dioxide gas from the reaction liquid and supplying it to the sealed space S.

[0058] Here, the decontamination target by the decontamination device and the decontamination method of the present invention is not limited to a safety cabinet, but is any device or equipment that has a sealed space and needs to be decontaminated. For example, an isolator for an animal breeding device is a device used for breeding laboratory animals, etc., which keeps the inside of the sealed space at positive or negative pressure and takes in and exhausts purified air through a HEPA filter.

[0059] Next, a more detailed configuration will be described.

[0060] [Concentration measurement mechanism] First, the concentration measuring mechanism 2 has a chlorine dioxide gas concentration measuring unit 20 (see FIG. 1). This chlorine dioxide gas concentration measuring unit 20 is a gas concentration detection device using a light absorption method, and has a measurement resolution of 0.001 ppm. Therefore, it is configured to be able to accurately measure the chlorine dioxide gas concentration in the internal environment of the sealed space S even at a concentration of 0.1 ppm or less.

[0061] This chlorine dioxide gas concentration measuring unit 20 has the feature of measuring the concentration of the target gas by making the gas absorb light instantly before the gas decomposes, and can adopt, for example, the gas concentration detection device described in Japanese Patent No. 6886208.

[0062] This chlorine dioxide gas concentration measuring unit 20 is a device that, for example, alternately introduces the measured air (air containing chlorine dioxide) in the measured space and clean air (clean gas) not containing the target gas (chlorine dioxide) in the clean area into a gas container, and obtains the concentration ch of the target gas (chlorine dioxide) in the measured air by irradiating it with light from a light source.

[0063] Chlorine dioxide (target gas) has a light absorption wavelength range of approximately 270 to 500 nm, with a maximum wavelength near 360 nm. Therefore, when air containing chlorine dioxide is irradiated with ultraviolet light of a wavelength of approximately 360 nm, the chlorine dioxide absorbs the ultraviolet light and is decomposed. Therefore, when the air containing chlorine dioxide (air to be measured) is irradiated with ultraviolet light and the transmitted light is observed, the amount of ultraviolet light decreases by the amount absorbed by the chlorine dioxide, that is, in proportion to the concentration ch of chlorine dioxide in the air to be measured. Therefore, the chlorine dioxide gas concentration measuring unit 20 can detect the concentration ch of chlorine dioxide by detecting this amount of decrease.

[0064] Moreover, the chlorine dioxide gas concentration measuring unit 20 is configured to be able to measure the chlorine dioxide gas concentration in the internal environment of the sealed space S at a frequency of once every 0.5 minutes. Moreover, in the embodiment of the present invention, the measurement frequency of the chlorine dioxide gas concentration in the internal environment of the sealed space S is preferably once every 0.5 to 3 minutes, more preferably once every 1 to 2 minutes, and even more preferably once every minute.

[0065] In addition, if the measurement is performed once per minute, the volume of the target sealed space S is small, and it is easy to properly check the concentration even if a sudden change in chlorine dioxide gas concentration occurs. In addition, compared to the case of measuring once every 0.5 minutes, the glass surface attached to the inside of the tube of the gas flow path and the light irradiation flow path inside the measuring device is less likely to become dirty with decomposition products of chlorine dioxide decomposed by ultraviolet rays, and the measurement accuracy can be prevented from decreasing.

[0066] The concentration measuring mechanism 2 also has a temperature and humidity measuring unit (not shown). The temperature and humidity measuring unit is a device that measures the temperature, relative humidity, and absolute humidity of the internal environment of the sealed space S. The chlorine dioxide gas concentration measuring unit 20 and the temperature and humidity measuring unit are configured to operate continuously so as to monitor the internal environment of the sealed space S.

[0067] The concentration measuring mechanism 2 also has an intake / exhaust path 21 for measuring the concentration. This intake / exhaust path 21 is connected to the inside of the sealed space S, and is a path that supplies the air in the sealed space S to the chlorine dioxide gas concentration measuring unit 20 or the temperature / humidity measuring unit, and returns the gas whose concentration, etc. has been measured back to the sealed space S.

[0068] In addition, a touch panel type sequencer 5 is provided at the location of the concentration measuring mechanism 2 (see Fig. 1). The sequencer 5 is a control device that automatically controls a series of work processes based on the measurement of the chlorine dioxide gas concentration and the temperature and humidity, such as dehumidification of the sealed space S, generation of chlorine dioxide gas, supply of chlorine dioxide gas to achieve the target gas concentration, calculation of the CT value, and collection and cleaning of the gas based on the CT value.

[0069] That is, the sequencer 5 is a control device (controller) that automatically controls all processes, including dehumidification of the confined space S before decontamination, supply (start-up) of chlorine dioxide gas, exposure of the confined space S to chlorine dioxide gas, recovery of chlorine dioxide gas after exposure, and cleaning of the solution supply path and the aeration tank.

[0070] The sequencer 5 referred to here corresponds to the sequencer in the claims of the present application. The details of the automatic control via the sequencer 5 will be described later.

[0071] In addition, the sequencer 5 is provided with a touch panel for operating each device. As described above, the decontamination equipment A can automatically control a series of operations from the preparation stage before decontamination to cleaning after exposure to chlorine dioxide gas is completed through the sequencer 5, but the start, pause, end, etc. of each processing step can also be controlled by operating the touch panel.

[0072] [Dehumidification and recovery mechanism] 1, the dehumidification and recovery mechanism 3 has a recovery cartridge unit 30 and a line blower 31. The dehumidification and recovery mechanism 3 also has a recovery supply and exhaust path 32 that connects from the exhaust port B1 of the safety cabinet B to the inside of the sealed space S again via the recovery cartridge unit 30 and the line blower 31.

[0073] The recovery cartridge portion 30 here corresponds to the recovery cartridge portion in the claims of the present application.

[0074] The collection cartridge section 30 is formed with two layers: an upper layer section 300 filled with activated carbon, and a lower layer section 301 filled with crystalline zeolite. A prefilter (not shown) is provided to sandwich the upper tank section 300 and the lower layer section 301 from above and below.

[0075] The activated carbon referred to here corresponds to the activated carbon in the claims of the present application, and the crystalline zeolite referred to here corresponds to the crystalline zeolite in the claims of the present application.

[0076] The upper layer 300 filled with activated carbon is a portion through which the air in the sealed space S passes after exposing the chlorine dioxide gas to the sealed space S, and the chlorine dioxide gas is adsorbed by the activated carbon and collected.

[0077] In addition, the lower layer 301 filled with crystalline zeolite is a part that passes air from the sealed space S before exposing the sealed space S to chlorine dioxide gas, and causes water molecules contained in the air to be adsorbed by the crystalline zeolite, thereby dehumidifying the sealed space S.

[0078] The prefilter is a filter member that prevents the fine powder of crystalline zeolite from moving before or after the upper layer portion 301 or the lower layer portion 300 due to the air from the line blower 31 .

[0079] In this way, the recovery cartridge section 30 is a component that performs two processes: dehumidification before decontamination by passing air inside the sealed space S, and recovery of gas after exposing the sealed space S to chlorine dioxide gas.

[0080] The activated carbon filled in the upper layer 300 is granular activated carbon made of pellet-shaped activated carbon or irregularly shaped crushed carbon, and the upper layer 300 is constructed by filling 800 g of granular activated carbon into a molding frame.

[0081] Here, the shape and size of the activated carbon packed in the upper layer portion 300 are not particularly limited as long as it is capable of adsorbing and recovering chlorine dioxide gas.

[0082] In addition, the amount of activated carbon filled in the upper layer 300 of the molding frame can be set appropriately. 3 ~5m 3 In consideration of the requirement for efficient exposure to chlorine dioxide gas in a short time and the number of times that the activated carbon is used, about one to three times, within the range of the volume, the amount of activated carbon filled in the upper layer 300 is preferably set to 50 g to 5000 g, more preferably 100 to 2000 g, and even more preferably set to 200 g to 1200 g.

[0083] The crystalline zeolite filled in the lower layer 301 is a crystalline zeolite capable of adsorbing substances with molecular diameters of less than 0.3 nm, and is an aluminosilicate crystalline material. It has minute pores in the crystals and is configured to be capable of selectively adsorbing water molecules. This crystalline zeolite is capable of adsorbing 20% ​​by weight of water molecules (water vapor). The lower layer 301 is filled with 800 g of crystalline zeolite.

[0084] Furthermore, even after the water molecule adsorption capacity of crystalline zeolite becomes saturated, its adsorption capacity can be regenerated by recovering it, washing it, and drying it.

[0085] Here, the amount of crystalline zeolite packed in the lower layer 301 can be appropriately set. However, if the volume of the enclosed space S is 1 m 3 ~5m 3 Before starting decontamination, the air in the enclosed space S within the volume range is kept at a relative humidity of less than 32% and an absolute humidity of 10 g / m 3 In order to maintain a low humidity environment of less than 50° C., the amount of crystalline zeolite packed in lower layer portion 301 is preferably set to 50 g to 2000 g, more preferably 100 to 1500 g, and even more preferably 200 g to 1000 g.

[0086] The line blower 31 is a blower for sucking air from within the sealed space S and passing the sucked air through the collection cartridge unit 30 via the collection supply and exhaust path 32. The line blower 31 is driven to dehumidify the sealed space S before decontamination and to collect the gas after exposure to chlorine dioxide gas.

[0087] [Gas generation mechanism] As shown in FIG. 1, the gas production mechanism 4 includes an aeration tank 40 , an air pump 41 , a gas supply tube 42 , a dehumidification cartridge 43 , a gas recovery tube 410 , and an activated carbon cartridge 411 .

[0088] The aeration tank 40 is a tank for mixing a chemical solution for generating chlorine dioxide gas. The chemical solution is mixed inside the aeration tank 40 to form an aqueous solution, which is aerated via an air pump 41 to liberate chlorine dioxide gas and generate a supply gas containing water vapor.

[0089] The air pump 41 is a member that sends air into the aeration tank 40 and aerates the aqueous solution mixed with the chemical solution of chlorine dioxide gas. The air pump 41 is a member that sucks in the gas in the sealed space S through the gas recovery tube 410 when generating chlorine dioxide gas, and sends the air that has passed through the activated carbon cartridge 411 into the aeration tank 40.

[0090] The air pump 41 is a blower that sends the supply gas generated in the aeration tank 40 through a gas supply tube 42 and from the supply port B2 of the safety cabinet B into the sealed space S.

[0091] Furthermore, the air pump 41 is a member that creates a positive pressure inside the sealed space S by its air pressure during a start-up process described later. By creating a positive pressure inside the sealed space S, the supplied chlorine dioxide gas is circulated inside the sealed space S, and the air inside can be returned to the device main body 1 side from the exhaust port B1 of the safety cabinet B.

[0092] In addition, by supplying chlorine dioxide gas to the sealed space, circulating it, and returning it to the device main body 1 via the air pump 41, gas supply tube 42, sealed space S, and gas recovery tube 410, the gas is circulated and positive pressure can be prevented from building up inside the sealed space S during the chlorine dioxide gas supply process.

[0093] The gas recovery tube 410 is a gas supply path connecting the air pump 41 and the exhaust port B4 of the safety cabinet B. The gas recovery tube 410 is also a path to which an activated carbon cartridge 411 is attached.

[0094] The activated carbon cartridge 411 is a component that is supplied into the sealed space S, where the chlorine dioxide gas is diluted in the space, and the diluted chlorine dioxide gas / air gas is passed through, and the chlorine dioxide gas is adsorbed by the activated carbon to turn it into fresh air, which is then returned to the air pump 41 side.

[0095] The gas supply tube 42 is a gas supply path that connects the aeration tank 40 and the supply port B2 of the safety cabinet B. The gas supply tube 42 is also a path to which a dehumidification cartridge 43 is attached.

[0096] In addition, the dehumidifying cartridge 43 is a component that passes the supply gas generated in the aeration tank 40, which is composed of chlorine dioxide gas and water vapor, captures and dehumidifies the water vapor, and supplies only chlorine dioxide gas to the inside of the sealed space S.

[0097] Moreover, the dehumidifying cartridge 43 is a cylindrical filled cartridge to which the gas supply tube 42 can be connected at two points, the supply side and the exhaust side.

[0098] The dehumidification cartridge 43 is filled with 150 g of crystalline zeolite capable of adsorbing substances with molecular diameters of less than 0.3 nm. This crystalline zeolite is the same substance as the crystalline zeolite filled in the lower layer 301 of the collection cartridge portion 30 described above.

[0099] In addition, pre-filters (not shown) are provided before and after the portion of the dehumidification cartridge 43 filled with crystalline zeolite. The pre-filters are filter members that prevent the fine powder of crystalline zeolite from being moved by the air of the air pump 41.

[0100] In addition, the dehumidifying cartridge 43 is configured to be detachable from the gas supply tube 42. As a result, after the adsorption capacity of the crystalline zeolite for water molecules becomes saturated, the dehumidifying performance can be guaranteed by replacing the entire dehumidifying cartridge 43.

[0101] Here, the amount of crystalline zeolite packed in the dehumidification cartridge 43 can be appropriately set. However, it is preferable that the amount of crystalline zeolite used here is set according to the temperature of the aqueous solution, the aeration capacity (bubbling capacity), and the aeration time.

[0102] Here, for example, in an aeration tank with a capacity of 1 L, aeration in the aeration tank was performed for 15 minutes with a bubbling capacity of 18 L / min, and the aeration rate of 10 m 3 When chlorine dioxide gas containing water vapor generated during generation was introduced into the closed space (when chlorine dioxide gas was not dehumidified), the relative humidity in the closed space rose from 40% RH to 50% RH when the temperature of the aqueous solution was 25°C. In addition, the absolute humidity was 1 m 3 2.31g per 10m 3 This is an increase of approximately 23g.

[0103] Considering the above example, since crystalline zeolite can adsorb 20% by weight of water molecules (water vapor), if 150 g of crystalline zeolite is filled in the dehumidifying cartridge 43, it can adsorb 30 g of water vapor. In other words, as in the above example, the approximately 23 g of water vapor generated by 15 minutes of aeration can be adequately collected by the dehumidifying cartridge 43.

[0104] In view of the above, in an embodiment of the present invention, in order to sufficiently capture the water vapor generated in the aeration tank 40, the amount of crystalline zeolite filled in the dehumidification cartridge 43 is preferably set to 1 g to 2000 g, and more preferably set to 50 to 200 g.

[0105] Next, the volume of the aeration tank 40 and the bubbling volume during aeration will be described.

[0106] First, in the present invention, as described later, in the exposure period in which the sealed space S is exposed to chlorine dioxide gas, the concentration of chlorine dioxide gas is preferably 250 ppm to 1500 ppm.

[0107] And, for example, 1m 3In order to achieve a chlorine dioxide gas concentration of approximately 250 ppm in a small enclosed space, the aeration tank must have a volume of at least 130 mL. 3 In order to make the chlorine dioxide gas concentration about 1500 ppm in a small sealed space, the aeration tank needs to have a volume of at least 180 mL. Also, considering that the main body 1 of the decontamination equipment A is installed each time decontamination is performed, and taking into account the size of the main body 1, the aeration tank is thought to have an upper limit of about 15 L (15000 mL). And, considering the size of the safety cabinet or the like to be decontaminated, the volume of the aeration tank is preferably 100 mL to 15000 mL, more preferably 200 mL to 5000 mL, and even more preferably set to 500 to 2000 mL.

[0108] In addition, the bubbling volume when aeration is performed by the air pump 41 is set in relation to the volume of the aeration tank. For example, when the volume of the aeration tank is 120 mL, the bubbling volume needs to be at least 0.2 L / min. In addition, if the bubbling volume is too small, the liberation of chlorine dioxide gas from the aqueous solution in the aeration tank slows down. Therefore, in consideration of the above-mentioned range of the volume of the aeration tank and efficient generation of chlorine dioxide gas, the bubbling volume is preferably set to 0.2 L to 100 L / min, more preferably 0.5 L to 50 L / min, and even more preferably 1 L to 30 L / min.

[0109] As shown in FIG. 1, the gas generation mechanism 4 has a chemical tank 44 , a chemical tank 45 , a water tank 46 , a waste liquid tank 47 , a chemical pump 48 , and a waste liquid pump 49 .

[0110] Here, the chemical tank 44 is filled with sodium chlorite (25% or less), and the chemical tank 45 is filled with hydrochloric acid (9% or less). The water tank 46 is filled with water for dilution or cleaning.

[0111] The waste liquid tank 47 is a tank for storing waste liquid generated when chlorine dioxide gas is produced. The waste liquid pump 49 is a pump for sending the waste liquid to the waste liquid tank 47.

[0112] The chemical pump 48 is a pump that delivers sodium chlorite (25% or less) from the chemical tank 44, hydrochloric acid (9% or less) from the chemical tank 45, and water from the water tank 46 when chlorine dioxide gas is produced in the aeration layer 40. The chemical pump 48 is also a pump that delivers water from the water tank 46 when cleaning the supply paths for each solution.

[0113] More specifically, when the chemical pump 48 is driven, sodium chlorite, hydrochloric acid and water are sent to the aeration tank 40, where they are mixed to become an aqueous solution. At the same time, aeration is performed by the air pump 41, and chlorine dioxide gas is generated.

[0114] Next, a flow of a decontamination method, which is an example of a decontamination method using chlorine dioxide gas to which the present invention is applied, will be described. Note that the decontamination method described below is a method using the above-mentioned decontamination apparatus A.

[0115] Figure 2 shows the main steps of the decontamination method. As shown in FIG. 2, the decontamination method to which the present invention is applied includes a dehumidification step (S1), a start-up step (S2), an exposure step (S3), and a recovery and cleaning step (S4).

[0116] Here, the dehumidification step (S1) is a step of collecting water molecules contained in the air inside the sealed space S of the safety cabinet B to dehumidify the space before decontamination.

[0117] In this process, the line blower 31 is driven to suck air inside the sealed space S into the device main body 1 through the recovery exhaust path 32. The sucked air also passes through the recovery cartridge part 30. When passing through the lower layer part 301 of the recovery cartridge part 30, water molecules contained in the sucked air are adsorbed by the crystalline zeolite. This causes the sucked air to be dehumidified and returned to the inside of the sealed space S again.

[0118] In this process, the temperature, relative humidity, and absolute humidity of the internal environment of the sealed space S are measured by the temperature and humidity measuring unit, and each measured value is monitored. In the dehumidification process (S1), the air inside the sealed space S is kept at a relative humidity of less than 32% and an absolute humidity of less than 10 g / m 3 Dehumidification continues until the humidity drops below 0.5%.

[0119] In addition, the air inside the enclosed space S has a relative humidity of less than 32% and an absolute humidity of 10 g / m 3 If it falls below this level, the driving of the line blower 31 is stopped, and the process proceeds to the next start-up step (S2).

[0120] This dehumidification process (S1) can create a low-humidity environment inside the sealed space S. Furthermore, the detection of the relative humidity and absolute humidity values, and the termination of the dehumidification process (S1) and the start of the start-up process (S1) based on the detection are automatically controlled by a sequencer 5.

[0121] Next, a start-up step (S2) is performed in which chlorine dioxide gas is generated to make the concentration of chlorine dioxide gas inside the sealed space S reach a target concentration value.

[0122] In this start-up step (S2), the air pump 41, the chemical pump 48, and the waste liquid pump 49 are driven to mix the chemicals inside the aeration tank 40, and the aqueous solution is aerated to liberate chlorine dioxide gas.

[0123] In addition, the chlorine dioxide gas liberated in the aeration tank 40 contains water vapor, but when it is sent by the air pump 41 through the gas supply tube 42 toward the inside of the sealed space S, it passes through the dehumidification cartridge section 43.

[0124] When passing through the dehumidifying cartridge portion 43, the water vapor contained in the chlorine dioxide gas is adsorbed by the crystalline zeolite. As a result, the water vapor is selectively collected, and only the chlorine dioxide gas is supplied into the sealed space S.

[0125] In the start-up step (S2), the air pump 41 sucks the gas in the sealed space S through the gas recovery tube 410, and sends the air that has passed through the activated carbon cartridge 411 to the aeration tank .

[0126] At this time, the chlorine dioxide gas is supplied into the sealed space S, where it is diluted, and the diluted chlorine dioxide gas / air gas is passed through the activated carbon cartridge 411, where the chlorine dioxide gas is adsorbed by the activated carbon to become fresh air, which is then returned to the air pump 41 side.

[0127] This allows the air in the closed space between the decontamination apparatus body and the sealed space S to be circulated and chlorine dioxide gas to be continuously supplied without causing rust in the air pump 41. As a result, it is no longer necessary to introduce new air from the outside space to perform aeration, and it is possible to prevent the inside of the sealed space from becoming positive pressure and to prevent chlorine dioxide gas from leaking to the outside. In addition, since the gas is circulated, the concentration of chlorine dioxide gas can be efficiently increased in the sealed space.

[0128] In this process, the chlorine dioxide gas concentration measuring unit 20 measures the chlorine dioxide gas concentration inside the sealed space S. This measurement of the chlorine dioxide gas concentration is performed automatically at set intervals.

[0129] In the start-up process (S2), the chlorine dioxide gas concentration in the sealed space S increases, and the generation and supply of the chlorine dioxide gas continues until the target concentration is reached. In this embodiment, the target concentration is set to 1500 ppm.

[0130] The target concentration of 1500 ppm for the chlorine dioxide gas is the concentration for making the CT value of the chlorine dioxide gas reach 1100 ppm·h in a short time inside the sealed space S in the exposure step (S3) described later. In addition, if the concentration is 1500 ppm or less, the flammability and explosion risk of the chlorine dioxide gas can be reduced, and the concentration of the chemical solution is below the level of a deleterious substance, making it easier to handle.

[0131] Furthermore, in the start-up process (S2), as described above, the dehumidification cartridge section 43 can capture water vapor generated when chlorine dioxide gas is generated, and it becomes possible to supply only chlorine dioxide gas to the inside of the sealed space S, so that the sealed space S can be maintained in a low humidity environment.

[0132] In addition, in the start-up process (S2), the air pressure of the air pump 41 creates a positive pressure inside the sealed space S, and the supplied chlorine dioxide gas is circulated inside the sealed space S, and the internal air can be returned to the device main body 1 side through the exhaust port B1 of the safety cabinet B.

[0133] Furthermore, when the concentration of chlorine dioxide gas in the air inside the sealed space S reaches 1500 ppm, the operation of the air pump 41, the chemical liquid pump 48, etc. is stopped, and the process proceeds to the next exposure step (S3).

[0134] At this time, for example, the measurement by the chlorine dioxide gas concentration measuring unit 20 can be set to measure the concentration at intervals of one minute of the measurement cycle. Also, the start-up process (S2) can be terminated when the concentration is measured twice as high as 1500 ppm.

[0135] In addition, the concentration measurement based on the chlorine dioxide gas concentration, the end of the start-up process (S2) based on the concentration measurement, and the start of the exposure process (S3) are automatically controlled by the sequencer 5.

[0136] Next, an exposure step (S3) is performed in which the sealed space S is exposed to chlorine dioxide gas while the supply of chlorine dioxide gas is stopped. In the exposure step (S3), while the sealed space S is filled with the introduced chlorine dioxide gas, the CT value is continuously calculated based on the concentration measurement by the chlorine dioxide gas concentration measurement unit 20.

[0137] In addition, when it is detected that the CT value has reached 1100 ppm·hr or more, the exposure process (S3) ends and the process proceeds to the next recovery and cleaning process (S4).

[0138] In this exposure step (S3), the walls and floor that form the sealed space S are exposed to chlorine dioxide gas, making it possible to reduce the number of microorganisms adhering thereto.

[0139] Furthermore, examples of microorganisms in the present embodiment include bacteria, fungi, viruses, etc. Chlorine dioxide has a wide antibacterial spectrum and exhibits excellent sterilizing and disinfecting effects against contaminants such as bacteria, fungi, and viruses.

[0140] For example, its effectiveness has been confirmed in bactericidal tests against Escherichia coli and Salmonella, as well as Legionella, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Lactococcus, Lactobacillus, Bacillus cereus, Clostridium, Campylobacter, Cladosporium, Fusarium, Rhizopus, Penicillium, Trichophyton, etc. It has also been confirmed to inactivate viruses such as influenza virus, norovirus, HIV, hepatitis B virus, rotavirus, and canine parvovirus.

[0141] In this exposure step (S3), chlorine dioxide gas is allowed to act on the sealed space S, thereby making it possible to effectively remove microorganisms in a short period of time.

[0142] In the recovery / cleaning step (S4), the air inside the sealed space S is sucked in, and the chlorine dioxide gas contained in the air is adsorbed to reduce the chlorine dioxide gas concentration in the sealed space S to less than 0.1 ppm. In addition, the chemical pump 49 is driven, and the liquid supply path such as the aeration tank 40 and the chemical pump is cleaned using water stored in the water tank 46.

[0143] In this recovery / cleaning step (S4), the line blower 31 is driven to suck air inside the sealed space S into the device body 1 side through the recovery exhaust path 32. The sucked air passes through the recovery cartridge part 30. When passing through the upper layer part 300 of the recovery cartridge part 30, the chlorine dioxide gas contained in the sucked air is adsorbed by the activated carbon. The air that has passed through the activated carbon is returned to the inside of the sealed space S again.

[0144] In this step, the chlorine dioxide gas concentration in the sealed space S is measured by the chlorine dioxide gas concentration measuring unit 20, and the measured value is monitored. In the recovery and cleaning step (S4), the chlorine dioxide gas is continuously recovered until the chlorine dioxide gas concentration in the air in the sealed space S becomes less than 0.1 ppm.

[0145] In the recovery / cleaning step (S4), in parallel with the recovery of chlorine dioxide gas by the recovery cartridge unit 30, the aeration tank 40, the liquid supply paths such as the chemical pump, and the like are cleaned.

[0146] When the chlorine dioxide gas concentration in the air inside the sealed space S becomes less than 0.1 ppm, the recovery and cleaning process (S4) is completed. In this state, the series of decontamination processes for the sealed space S is completed, and the safety cabinet B can be used.

[0147] In this case, for example, the measurement by the chlorine dioxide gas concentration measuring unit 20 can be set to measure the concentration at intervals of one minute. Also, the recovery and washing step (S4) can be terminated when the concentration is less than 0.1 ppm twice.

[0148] Furthermore, the measurement of the chlorine dioxide gas concentration and the termination of the recovery and washing step (S4) based on this concentration are automatically controlled by a sequencer 5.

[0149] The decontamination method to which the present invention is applied is carried out according to the above-mentioned flow.

[0150] In the present embodiment, in the dehumidification step (S1), the enclosed space S is kept at a relative humidity of less than 32% and an absolute humidity of 10 g / m 3 The low humidity environment is maintained at less than 100° C., and in the start-up step (S2), water vapor is collected and only chlorine dioxide gas is supplied to the sealed space, thereby making it possible to maintain the low humidity environment.

[0151] This makes it possible to sufficiently prevent the contents of the target sealed space S from corroding when decontamination is performed using chlorine dioxide gas.

[0152] In this embodiment, by supplying chlorine dioxide gas to the sealed space S in the start-up step (S2) so that the concentration of chlorine dioxide gas becomes 1500 ppm, it becomes possible to make the CT value of chlorine dioxide gas reach 1100 ppm·hr in a short time in the exposure step (S3). In addition, by making the CT value reach 1100 ppm·hr, it becomes possible to sufficiently reduce the number of microorganisms attached inside the sealed space S.

[0153] In addition, in this embodiment, in the recovery and cleaning step (S4), chlorine dioxide gas is adsorbed through activated carbon in the recovery cartridge portion 30, making it possible to recover the chlorine dioxide gas in the sealed space S in a short time so that the chlorine dioxide gas concentration becomes less than 0.1 ppm.

[0154] As described above, the decontamination apparatus of the present invention can maintain a sufficiently low humidity environment within the enclosed space to be decontaminated during decontamination, thereby preventing corrosion within the space, and is also highly safe and capable of completing decontamination work in a short period of time. In addition, the decontamination method using chlorine dioxide gas of the present invention maintains a sufficiently low humidity environment within the enclosed space to be decontaminated during decontamination, thereby preventing corrosion within the space, and is also safe and capable of completing the decontamination work in a short period of time.

[0155] The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the present invention is not limited to the above embodiment and can be modified in various ways without departing from the gist of the invention. EXAMPLES

[0156] The following examples are provided.

[0157] [Relative humidity and absolute humidity in an enclosed space] Based on the above-mentioned configuration of the decontamination apparatus A, the influence of the presence or absence of the dehumidification cartridge unit 43 was examined. The one provided with the dehumidification cartridge unit 43 was used as Example 1, and the one not provided with the dehumidification cartridge unit 43 in the gas supply tube 42 was used as Comparative Example. In this example, the dehumidification cartridge unit 43 was filled with 100 g of crystalline zeolite (product name: molecular sieve 3A 1 / 16: manufactured by Kanto Chemical Co., Ltd.). In addition, for the Example and Comparative Example, the chlorine dioxide gas concentration and the relative humidity in the sealed space S were measured at each time point before the start of the supply of chlorine dioxide gas (elapsed time 0 minutes), at the end of the 10-minute start-up process (elapsed time 10 minutes), and at the end of the exposure process (elapsed time 70 minutes). The results are shown in Tables 1 and 2 and in Figures 3(a) and 3(b). Tables 1 and 3(a) show the results of Example 1, and Table 2 and Figure 3(b) show the results of Comparative Example.

[0158] (Table 1) JPEG0007668999000001.jpg1678

[0159] (Table 2) JPEG0007668999000002.jpg1879

[0160] As shown in Table 1 and Fig. 3(a), in Example 1, the relative humidity inside the sealed space S could be maintained at a low humidity of less than 32%. On the other hand, as shown in Table 2 and Fig. 3(b), in the comparative example, the relative humidity inside the sealed space S increased with time, and at the end of the exposure step, the relative humidity was 43%.

[0161] Next, a series of treatments were carried out on the safety cabinet B using the decontamination method to which the present invention is applied (Example 2). The decontamination method was carried out under automatic control by the sequencer 5. Biological indicators (BI) were placed at six locations in the sealed space S of the safety cabinet B, and decontamination was carried out to confirm the presence or absence of sterilization of the indicator bacterium B. atrophaeus. Figure 4 shows the changes in chlorine dioxide gas concentration and chlorine dioxide gas CT value (ppm·h) over time in the sealed space S, and Figure 5 shows the changes in temperature, absolute humidity, and relative humidity over time in the sealed space S.

[0162] In Example 2, 2.0 x 10 6 After decontamination, the cfu of B. atrophaeus was reduced by 6 logs (to 2.0 cfu or less).

[0163] As shown in FIG. 4, in Example 2, the concentration reached 1200 ppm·hr in the exposure step of 60 minutes. In the recovery step, the recovery of chlorine dioxide gas was completed in about 10 minutes. Furthermore, as shown in FIG. 5, in Example 2, the inside of the sealed space S was maintained at a relative humidity of less than 32% and an absolute humidity of less than 10 g / m 3 The samples were kept in a low humidity environment of less than 5%.

[0164] [Preventing positive pressure when supplying chlorine dioxide gas to an enclosed space] As shown in Figure 6, the above-mentioned decontamination equipment A is 3 The device was installed outside the sealed chamber S1 having an area of ​​100 mm. Two kinds of chemical liquids were sent to the aeration tank by a chemical liquid pump and reacted to generate chlorine dioxide water. In addition, air taken in from the sealed chamber S1 by a gas recovery tube 410 by an air pump was sent to the aeration tank, and chlorine dioxide gas separated by aeration was sent to the sealed chamber S1 by a gas supply tube 42. In addition, the pressure in the sealed chamber S1 was measured over time, and the concentration of chlorine dioxide gas leaking out of the sealed chamber S1 was measured.

[0165] A pressure gauge P (Universal digital UPM60P-F1) for measuring air pressure and a circulator C for mixing air were installed in the sealed chamber S1, and a chlorine dioxide gas measuring instrument G (ATi chlorine dioxide gas concentration measuring instrument B12 type) was installed outside the sealed chamber S1. On the outer wall of the sealed chamber S1, there is an opening and closing plate S10 for inserting and removing materials and equipment, and the periphery of the opening and closing plate S10 was sealed in advance with masking tape T to prevent gas leakage.

[0166] (Table 3) JPEG0007668999000003.jpg1199

[0167] Table 3 shows the change in pressure over time in the sealed chamber S1 and the change in the concentration of chlorine dioxide gas leaked to the outside. As a result, the air pressure in the sealed chamber S1 did not change from the initial time and the internal pressure did not increase over time. In addition, no chlorine dioxide gas was found to leak to the outside of the sealed chamber S1. [Explanation of symbols]

[0168] A Decontamination equipment 1 Operation unit 2. Concentration measurement mechanism 20 Chlorine dioxide gas concentration measuring unit 21 Air supply and exhaust route 3. Dehumidification and recovery mechanism 30 Collection cartridge section 300 Upper Management 301 Lower part 31 Line Blower 32 Recovery supply and exhaust route 4. Gas generation mechanism 40 Aeration tank 41 Air Pump 410 Gas collection tube 411 Activated carbon cartridge 42 Gas supply tube 43 Dehumidifying cartridge 44 Chemical tank 45 Chemical tank 46 Water Tank 47 Waste Liquid Tank 48 Chemical Pump 49 Wastewater Pump 5. Sequencer B. Safety cabinet B1 Exhaust port B2 supply port B3 Supply port S closed space

Claims

1. A decontamination method using chlorine dioxide gas for reducing a predetermined microorganism in an enclosed space by applying chlorine dioxide gas to the enclosed space, comprising: The air in the sealed space is sucked in and dehumidified, and the dehumidified air is returned to the sealed space to maintain a relative humidity of less than 32% and an absolute humidity of 10 g / m ３ a dehumidification process for creating an environment below 100°C; a chlorine dioxide gas supplying step of generating a supply gas containing chlorine dioxide gas and water vapor, dehumidifying the supply gas before supplying the supply gas to the sealed space, and supplying the chlorine dioxide gas into the sealed space; an exposure step of exposing the sealed space to chlorine dioxide gas after the chlorine dioxide gas supply step, by stopping the supply of the chlorine dioxide gas to the sealed space; and a recovery step of recovering the chlorine dioxide gas by sucking the air in the sealed space after the exposure step, and reducing the concentration of the chlorine dioxide gas in the sealed space to less than 0.1 ppm. Decontamination method using chlorine dioxide gas.

2. In the chlorine dioxide gas supply step, the supply gas is passed through crystalline zeolite capable of adsorbing substances with molecular diameters of less than 0.3 nm to dehumidify the gas. A decontamination method using chlorine dioxide gas according to claim 1.

3. In the dehumidification step, the air in the sealed space is passed through the crystalline zeolite to dehumidify it. The method for decontamination using chlorine dioxide gas according to claim 2.

4. In the chlorine dioxide gas supplying step, the chlorine dioxide gas is supplied to the sealed space at a concentration in the range of 250 ppm to 1500 ppm. A decontamination method using chlorine dioxide gas according to claim 1 or 2.

5. In the exposure step, the sealed space is exposed to chlorine dioxide gas until the CT value reaches at least 1100 ppm-hour. A decontamination method using chlorine dioxide gas according to claim 1 or 2.

6. When it is detected that the CT value of the chlorine dioxide gas in the sealed space reaches a target value in the exposure step, the recovery step is automatically started. A decontamination method using chlorine dioxide gas according to claim 1 or 2.

7. In the chlorine dioxide gas supply step and the exposure step, the inside of the sealed space is kept at a relative humidity of less than 32% and an absolute humidity of less than 10 g / m ３ Maintain an environment below A decontamination method using chlorine dioxide gas according to claim 1 or 2.

8. In the chlorine dioxide gas supply step, the gas in the sealed space is sucked in, passed through activated carbon, and then used to generate the supply gas. A decontamination method using chlorine dioxide gas according to claim 1 or 2.

9. The enclosed space is a safety cabinet or an isolator for animal breeding. A decontamination method using chlorine dioxide gas according to claim 1 or 2.

10. A decontamination apparatus for reducing a predetermined microorganism in an enclosed space by applying chlorine dioxide gas to the enclosed space, A decontamination apparatus body connected to a gas supply port and an exhaust port provided on the sealed space side via piping paths; A humidity measuring unit for measuring the relative humidity and the absolute humidity in the enclosed space; A gas concentration measuring unit for measuring the concentration of chlorine dioxide gas in the sealed space; The air sucked from the sealed space is dehumidified to maintain the relative humidity in the sealed space at less than 32% and the absolute humidity at 10 g / m ３ a first dehumidification unit that creates an environment of less than 100°C; an aeration tank for mixing the chlorine dioxide gas chemical; an air pump that supplies gas to the aeration tank to generate a supply gas containing the chlorine dioxide gas and water vapor, and sends the supply gas toward the sealed space through the piping path connected to the supply port; a second dehumidification unit provided on the piping path connected to the supply port and configured to dehumidify the supply gas; a recovery section that sucks in the air in the sealed space that has been exposed to the chlorine dioxide gas for a certain period of time, recovers the chlorine dioxide gas, and reduces the concentration of the chlorine dioxide gas in the sealed space to less than 0.1 ppm. Decontamination equipment.

11. The second dehumidifying unit has a crystalline zeolite capable of adsorbing substances having a molecular diameter of less than 0.3 nm. The decontamination apparatus according to claim 10.

12. The first dehumidification unit has crystalline zeolite. The decontamination apparatus according to claim 10.

13. The recovery section includes activated carbon. The decontamination apparatus according to claim 10 or 11.

14. The collecting cartridge part includes a layer having the first dehumidifying part and a layer having the collecting part. The decontamination apparatus according to claim 10 or 11.

15. and a sequencer that automatically controls the operation of the aeration tank, the air pump, and the recovery unit based on the relative humidity and absolute humidity in the sealed space measured by the humidity measurement unit, or the concentration of the chlorine dioxide gas measured by the gas concentration measurement unit. The decontamination apparatus according to claim 10 or 11.

16. The gas concentration measuring unit measures the concentration of the chlorine dioxide gas by a light absorption method and has a measurement resolution of 0.001 ppm. The decontamination apparatus according to claim 10 or 11.

17. The air pump is connected to the exhaust port, and sucks gas from the sealed space through the piping path provided with a gas purifying unit made of activated carbon, and sends the sucked gas to the aeration tank. The decontamination apparatus according to claim 10 or 11.

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