JP7525992B2 - Decontamination Equipment - Google Patents

Description

The present invention relates to a decontamination device, and in particular to a decontamination device configured to decontaminate a target space.

Japanese Patent Publication No. 6285060 (Patent Document 1) discloses a decontamination device for decontaminating sterile manufacturing facilities and the like. This decontamination device uses a dry fog containing peracetic acid to decontaminate the space to be decontaminated (biodecontamination). In this decontamination device, the relative humidity in the space to be decontaminated is controlled by using a gas recovery machine (dehumidifier) during decontamination. Therefore, with this decontamination device, the relative humidity in the space to be decontaminated does not increase excessively, and it is possible to suppress the situation in which equipment in the space to be decontaminated breaks down or corrodes due to condensation.

Patent No. 6285060

To improve the effectiveness of decontamination using peracetic acid, it is necessary to keep the relative humidity in the space to be decontaminated (hereinafter simply referred to as the "target space") relatively high. On the other hand, if the relative humidity in the target space becomes excessively high, there is a high possibility that equipment in the target space will break down or corrode due to condensation.

In the decontamination equipment disclosed in the above-mentioned Patent Document 1, the relative humidity in the target space is controlled by using a gas recovery machine (dehumidifier) during decontamination. However, in this case, the use of a dehumidifier increases the size of the decontamination equipment. In addition, the dehumidifier also recovers dry fog (hereinafter also referred to as "peracetic acid gas") containing peracetic acid, which reduces the concentration of peracetic acid in the target space and reduces the decontamination effect. Furthermore, because the dehumidifier recovers peracetic acid gas, there is a possibility that the dehumidifier will break down early due to the adhesion of peracetic acid.

For example, exhausting the air during decontamination may be considered in order to control the relative humidity in the target space. However, if exhausting the air during decontamination, the exhaust gases have adverse effects on people and the external environment. In addition, peracetic acid gas is also exhausted, which reduces the concentration of peracetic acid in the target space and reduces the decontamination effect.

The present invention has been made to solve these problems, and its purpose is to provide a decontamination device that can maintain the concentration of peracetic acid and the relative humidity in a target space within an appropriate range without dehumidifying or exhausting the air during decontamination of the target space.

The decontamination apparatus according to the present invention is configured to decontaminate a target space with peracetic acid. The decontamination apparatus includes a first emission section and a second emission section. The first emission section is configured to emit a first gas resulting from a first decontamination agent. The second emission section is configured to emit a second gas resulting from a second decontamination agent. The concentration of peracetic acid in the second decontamination agent is higher than the concentration of peracetic acid in the first decontamination agent. Each of the first emission section and the second emission section operates so as not to wet the wall surface of the target space.

In this decontamination apparatus, a first decontamination agent and a second decontamination agent, each of which has a different concentration of peracetic acid, are used. Therefore, according to this decontamination apparatus, by appropriately using the first decontamination agent and the second decontamination agent, it is possible to maintain the concentration of peracetic acid and the relative humidity in the target space within an appropriate range without dehumidifying or exhausting the air, and to prevent the walls of the target space from becoming wet.

In the above decontamination device, the generation method of each of the first gas and the second gas may be an atomization method or a vaporization method.

The decontamination apparatus further includes a control unit configured to control the first release unit and the second release unit, and the control unit may control the first release unit to release the first gas until the relative humidity in the target space reaches a predetermined value, and may control the second release unit to intermittently release the second gas after the relative humidity reaches the predetermined value.

When this decontamination device is used, the first gas is released to first raise the relative humidity in the target space to a predetermined value (the relative humidity at which the decontamination effect of peracetic acid is sufficient), and then the second gas is intermittently released to suppress the increase in relative humidity and the decrease in the concentration of peracetic acid. Therefore, with this decontamination device, it is possible to suppress the occurrence of condensation caused by an excessive increase in relative humidity in the target space without dehumidifying or exhausting, and it is possible to effectively decontaminate the target space.

The present invention provides a decontamination device that can maintain the concentration of peracetic acid and the relative humidity in a target space within an appropriate range without dehumidifying or exhausting the air during decontamination of the target space.

FIG. 1 is a diagram for explaining an overview of a decontamination device. FIG. 1 is a diagram showing a schematic configuration of a decontamination apparatus. 4A and 4B are diagrams illustrating a schematic configuration of a first emission section. 4A and 4B are diagrams illustrating a schematic configuration of a second emission section. 4 is a flowchart showing an operation procedure of the decontamination apparatus. FIG. 13 is a graph showing the changes in relative humidity and peracetic acid concentration in a target space. FIG. 13 is a diagram showing changes in temperature, humidity, and peracetic acid concentration in a space to be decontaminated in an embodiment. FIG. 13 is a diagram showing changes in temperature, humidity, and peracetic acid concentration in a space to be decontaminated in a comparative example.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals and their description will not be repeated.

[1. Overview]
1 is a diagram for explaining an overview of a decontamination apparatus 100 according to the present embodiment. As shown in FIG. 1, the decontamination apparatus 100 is used in a space 200.

Space 200 is the space to be decontaminated (target space), and is, for example, a space within a sterile manufacturing facility, a sterile testing room, a manufacturing facility for regenerative medical products, a sterile laboratory animal breeding room, an operating room, a food manufacturing facility, or a facility for handling and managing pathogenic microorganisms (hereinafter, simply referred to as "facilities, etc."). Space 200 may also be, for example, the internal space of a device installed within a facility, etc. In other words, space 200 may be, for example, the space within a safety cabinet, which is a box-shaped experimental facility for suppressing biohazards.

The decontamination device 100 is a device for decontaminating (biodecontaminating) the space 200. The decontamination device 100 is configured to decontaminate the space 200 by releasing peracetic acid gas into the space 200.

To enhance the effectiveness of decontamination using peracetic acid, it is necessary to keep the relative humidity in the space 200 at a certain level. On the other hand, if the relative humidity in the space 200 becomes excessively high, there is a high possibility that equipment in the space 200 will break down or corrode due to condensation.

In order to control the relative humidity in the space 200, it is possible to install a dehumidifier in the decontamination equipment and use the dehumidifier during decontamination. However, in this case, since the dehumidifier is installed in the decontamination equipment, the size of the decontamination equipment becomes larger. In addition, since the dehumidifier also collects peracetic acid gas, the concentration of peracetic acid in the space 200 decreases, and the decontamination effect decreases. Furthermore, since the dehumidifier collects peracetic acid gas, there is a possibility that the dehumidifier will break down early due to the adhesion of peracetic acid.

For example, exhausting air during decontamination may be considered in order to control the relative humidity in the space 200. However, if exhausting air during decontamination, the exhaust gas will have adverse effects on people and the external environment. In addition, peracetic acid gas is also exhausted, which reduces the concentration of peracetic acid in the target space and reduces the decontamination effect.

In decontamination of the space 200 using the decontamination apparatus 100 according to this embodiment, the concentration of peracetic acid and the relative humidity in the space 200 are maintained within an appropriate range without dehumidification or exhaust during decontamination. The configuration and operation of the decontamination apparatus 100 are described in detail below.

[2. Configuration of decontamination equipment]
Fig. 2 is a diagram showing a schematic configuration of the decontamination apparatus 100. As shown in Fig. 2, the decontamination apparatus 100 includes a first discharging section 110, a second discharging section 120, and a control section 130. Note that, for example, in order to control the first discharging section 110 and the second discharging section 120 based on the humidity and the peracetic acid concentration in the space 200, the control section 130 may have a humidity sensor function and a peracetic acid concentration sensor function.

Figure 3 is a diagram showing a schematic configuration of the first release section 110. The first release section 110 is configured to release the first gas (peracetic acid gas) resulting from the first decontamination agent 112 to the outside of the first release section 110. As shown in Figure 3, the first release section 110 includes a container 111, a first decontamination agent 112, a lid 113, and fans 114 and 115.

The container 111 is made of a material that is not corroded by the decontamination agent, such as metal or resin, and is configured to contain a first decontamination agent 112. The first decontamination agent 112 is an aqueous solution containing peracetic acid. The lid 113 is attached to the upper end of the container 111. Openings O1 and O2 are formed in the lid 113, and fans 114 and 115 are attached to the openings O1 and O2, respectively.

Fan 114 is configured to generate an airflow from the outside to the inside of first release section 110 by rotating. On the other hand, fan 115 is configured to generate an airflow from the inside to the outside of first release section 110 by rotating. As fans 114 and 115 rotate, peracetic acid gas (first gas) generated by evaporation of first decontamination agent 112 is released to the outside of first release section 110. In other words, the method of generating peracetic acid gas in first release section 110 is vaporization type.

Figure 4 is a diagram showing a schematic configuration of the second release section 120. The second release section 120 is configured to release the second gas (peracetic acid gas) resulting from the second decontamination agent 122 to the outside of the second release section 120. As shown in Figure 4, the second release section 120 differs from the first release section 110 only in the decontamination agent contained in the container 111. In the second release section 120, the second decontamination agent 122 is contained in the container 111. The second decontamination agent 122 is an aqueous solution containing peracetic acid. The concentration of peracetic acid in the second decontamination agent 122 is higher than the concentration of peracetic acid in the first decontamination agent 112. For example, the concentration of peracetic acid in the second decontamination agent 122 may be more than twice that of peracetic acid in the first decontamination agent 112.

In the second release section 120, the fans 114 and 115 rotate, and the peracetic acid gas (second gas) generated by the evaporation of the second decontamination agent 122 is released to the outside of the second release section 120. In other words, the method of generating the peracetic acid gas in the second release section 120 is vaporization.

The control unit 130 is configured to control the first emission unit 110 and the second emission unit 120. More specifically, the control unit 130 is configured to control the fans 114, 115 included in each of the first emission unit 110 and the second emission unit 120. The control unit 130 includes a hardware processor such as a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory), and is configured to execute information processing based on programs and various data.

[3. Operation of the decontamination equipment]
5 is a flowchart showing an operation procedure of the decontamination apparatus 100. The process shown in this flowchart is started, for example, when an operator using the decontamination apparatus 100 performs an operation for operating the decontamination apparatus 100.

Figure 6 is a diagram showing the progression of the relative humidity and the peracetic acid concentration in the space 200. In Figure 6, the horizontal axis indicates time, and the vertical axis indicates the relative humidity or the peracetic acid concentration. In addition, the solid line L1 indicates the progression of the relative humidity, and the solid line L2 indicates the progression of the peracetic acid concentration.

5 and 6, the control unit 130 controls the first release unit 110 to start releasing the first gas (step S100). More specifically, the control unit 130 controls the fans 114 and 115 included in the first release unit 110 to start rotating. During the release of the first gas (peracetic acid gas), the relative humidity and the peracetic acid concentration in the space 200 each increase.

The control unit 130 determines whether a first predetermined time (t1) has elapsed since the release of the first gas was started (step S110). The first predetermined time (t1) is, for example, the time at which the relative humidity in the space 200 reaches H1, which is lower than H2 (the humidity at which condensation is likely to occur), and the peracetic acid concentration in the space 200 reaches a concentration higher than C1 at which decontamination can be effectively performed. The relative humidity H1 is predetermined as a value at which the relative humidity does not exceed H2 when the time t6 from the start to the end of decontamination has elapsed, and the first predetermined time (t1) is predetermined as the time at which the relative humidity in the space 200 reaches H1.

When it is determined that the first predetermined time has not elapsed (NO in step S110), the control unit 130 controls the first release unit 110 to continue releasing the first gas. On the other hand, when it is determined that the first predetermined time has elapsed (YES in step S110), the control unit 130 controls the first release unit 110 to stop releasing the first gas (step S120). When the first predetermined time (t1) is reached, the relative humidity in the space 200 reaches, for example, H1, and the peracetic acid concentration in the space 200 reaches, for example, a value equal to or higher than C1.

The control unit 130 further determines whether it is time to end the decontamination in the space 200 (step S130). That is, the control unit 130 determines whether time t6 has elapsed since the start of decontamination in the space 200. Time t6 is predetermined as the time when decontamination in the space 200 is completed. When it is determined that it is time to end (YES in step S130), the decontamination operation by the decontamination apparatus 100 ends.

On the other hand, if it is determined that the end timing has not yet arrived (NO in step S130), the control unit 130 determines whether or not a second predetermined time has elapsed since the release of peracetic acid gas was stopped (step S140). The second predetermined time is, for example, the time it takes for the peracetic acid concentration in the space 200 to decrease to C1 due to the decomposition of peracetic acid, and is determined in advance. If it is determined that the second predetermined time has not elapsed (NO in step S140), the control unit 130 maintains the stopped state of the first release unit 110 and the second release unit 120.

On the other hand, when it is determined that the second predetermined time has elapsed (YES in step S140), the control unit 130 controls the second release unit 120 to start releasing the second gas (step S150). More specifically, the control unit 130 controls the fans 114, 115 included in the second release unit 120 to start rotating. During the release of the second gas (peracetic acid gas), the relative humidity and the peracetic acid concentration in the space 200 each increase again. Since the peracetic acid concentration of the second gas is higher than that of the first gas, during the release of the second gas, the peracetic acid concentration increases rapidly while the relative humidity increases slowly compared to during the release of the first gas.

Then, the control unit 130 determines whether or not a third predetermined time has elapsed since the release of the second gas started (step S160). The third predetermined time is the time required for the concentration of peracetic acid in the space 200 to increase sufficiently, and is determined in advance. If it is determined that the third predetermined time has not elapsed (NO in step S160), the control unit 130 controls the second release unit 120 to continue releasing the second gas.

On the other hand, if it is determined that the third predetermined time has elapsed (YES in step S160), the control unit 130 controls the second release unit 120 to stop releasing the second gas (step S170). Then, the process proceeds to step S130.

In this way, in the decontamination apparatus 100, the second gas is intermittently released by the second release section 120 until the timing for the end of decontamination arrives. According to the decontamination apparatus 100, the concentration and relative humidity of peracetic acid in the space 200 can be maintained within an appropriate range without dehumidification or exhaust by appropriately using the first release section 110 (first decontamination agent 112) and the second release section 120 (second decontamination agent 122).

The first predetermined time (t1), the second predetermined time, the third predetermined time, and time t6, as well as the peracetic acid concentration in each of the first decontamination agent 112 and the second decontamination agent 122, can be appropriately changed to an optimal value depending on conditions such as the volume of the space to be decontaminated and the initial humidity.

In addition, in this embodiment, the start and stop of the first gas and second gas release are controlled based on the elapsed time. However, the start and stop of the first gas and second gas release do not necessarily need to be controlled based on the elapsed time. For example, the stop of the first gas release may be controlled based on the relative humidity in the space 200, and the start and stop of the second gas release may be controlled based on the peracetic acid gas concentration in the target space. For example, the control unit 130 may control the first release unit 110 to stop the release of the first gas when a humidity sensor included in the control unit 130 detects that the relative humidity in the space 200 has reached H1, control the second release unit 120 to start the release of the second gas when a peracetic acid concentration sensor included in the control unit 130 detects that the peracetic acid concentration in the space 200 has decreased to C1, and control the second release unit 120 to stop the release of the second gas when a peracetic acid concentration sensor included in the control unit 130 detects that the peracetic acid concentration in the space 200 has reached a predetermined sufficiently high value.

[4. Features]
As described above, the first decontamination agent 112 and the second decontamination agent 122, each of which has a different concentration of peracetic acid, are used in the decontamination apparatus 100. Therefore, according to the decontamination apparatus 100, by appropriately using the first decontamination agent 112 and the second decontamination agent 122, it is possible to maintain the concentration of peracetic acid and the relative humidity in the space 200 within an appropriate range without dehumidifying or exhausting the air, and to prevent the wall surface of the space 200 from becoming wet.

Furthermore, when the decontamination apparatus 100 is used, the first gas is released to first raise the relative humidity in the space 200 to a predetermined value (the relative humidity at which the decontamination effect by peracetic acid is sufficient), and then the second gas is intermittently released to suppress the increase in relative humidity and the decrease in the concentration of peracetic acid. Therefore, the decontamination apparatus 100 can suppress the occurrence of condensation caused by an excessive increase in relative humidity in the space 200 without dehumidifying or exhausting, and can effectively decontaminate the space 200.

5. Modifications
Although the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

(5-1)
In the above embodiment, the first gas and the second gas are generated by vaporization. However, the first gas and the second gas are not limited to this. For example, the first gas and the second gas may be generated by atomization (ultrasonic or air spray). In order to prevent corrosion of the space 200, it is preferable that each spray method does not wet the wall surface of the space 200. In order not to wet the wall surface, it is preferable that the material emitted from each of the first emission part 110 and the second emission part 120 is gas or fine particles of droplets with a particle size of 15 μm or less.

(5-2)
In the above embodiment, the decontamination apparatus 100 decontaminates the space 200 by emitting peracetic acid gas. However, the decontamination apparatus 100 does not necessarily have to emit peracetic acid gas. For example, the decontamination apparatus 100 may be configured to emit peracetic acid in the form of a mist.

(5-3)
In the above embodiment, the first emitting portion 110 and the second emitting portion 120 are structurally identical. However, the first emitting portion 110 and the second emitting portion 120 do not necessarily have to be structurally identical.

(5-4)
In the above embodiment, the first decontamination agent 112 is an aqueous solution containing peracetic acid. However, the first decontamination agent 112 does not necessarily have to be an aqueous solution containing peracetic acid. The first decontamination agent 112 may be, for example, simply water.

[6. Examples, etc.]
Examples and comparative examples will be described below.

(Various devices, etc.)
In the examples and comparative examples, the following devices were prepared. A class II safety cabinet (SCV-1308-EC II A2 manufactured by Hitachi Industrial Equipment Systems Co., Ltd.) was prepared as the space to be decontaminated. An LR5001 manufactured by HIOKI EE Corporation was prepared as the thermo-hygrometer. An F12/D-3-6-1-1 manufactured by ATI Co., Ltd., which is the peracetic acid concentration meter body, and an 00-1705 manufactured by ATI Co., Ltd., which is the sensor module, were prepared as the peracetic acid concentration meter.

The first gas generator (vaporization type) was prepared by attaching two fans with a size of 120 mm for inlet and outlet to the top of a box with a bottom (inner dimensions) of about 45 cm x 31 cm and a height of about 26 cm. The second gas generator (vaporization type) was prepared by attaching two fans with a size of 60 mm for inlet and outlet to the top of a box with a bottom (inner dimensions) of about 37 cm x 28 cm and a height of about 15 cm. In addition, HMV-091 manufactured by MesaLabs was prepared as a biological indicator (10 ⁶ ) for confirming decontamination. Three biological indicators were installed in each experiment.

In both the examples and comparative examples, the work space of the safety cabinet and the secondary side of the exhaust HEPA were protected, and decontamination was carried out while preventing leakage to outside air as much as possible. In addition, the thermometer/hygrometer, peracetic acid concentration meter, gas generator, and biological indicator were all installed within the work space. Each gas generator was installed near the center of the work space, and the other measuring instruments and biological indicator were installed at a reasonable distance from walls and other equipment so as not to interfere with the flow of air. The biological indicator was installed in an upright position, held by a clip.

(Example)
In this embodiment, 1000 ml of a solution with a peracetic acid concentration of 0.06% was placed in the first gas generator, and 500 ml of a solution with a peracetic acid concentration of 0.45% was placed in the second gas generator.

In this embodiment, the first gas generator was operated until the humidity in the space to be decontaminated reached 85%. After the humidity reached 85%, the second gas generator was operated. After the first operation of the second gas generator, the second gas generator was repeatedly stopped and started according to the following rules.

(1) When the concentration of peracetic acid in the space to be decontaminated falls to 15 ppm, the second gas generator is operated. (2) When the concentration of peracetic acid in the space to be decontaminated rises to 20 ppm, the second gas generator is stopped. Note that in this embodiment, the operation and stop of the second gas generator was switched manually, so there may be cases where the above rules are not followed.

Decontamination was completed approximately 3 hours after the start of the first gas release, and the biological indicators were collected and cultured. In this example, all (3) biological indicators installed were negative (dead).

Figure 7 shows the changes in temperature, humidity, and peracetic acid concentration in the space to be decontaminated in the embodiment. As shown in Figure 7, in the embodiment, the relative humidity and peracetic acid concentration in the space to be decontaminated were controlled within an appropriate range.

Comparative Example
In the comparative example, 1000 ml of a solution with a peracetic acid concentration of 0.06% was placed in the first gas generator. In the comparative example, the first gas generator was operated until the humidity in the space to be decontaminated reached 85%. After the humidity reached 85%, the first gas generator was repeatedly stopped and started according to the following rules.

(1) When the concentration of peracetic acid in the space to be decontaminated falls to 15 ppm, operate the first gas generator. (2) When the concentration of peracetic acid in the space to be decontaminated rises to 20 ppm, stop the first gas generator.

After about two hours, the relative humidity in the space to be decontaminated exceeded 90%. Condensation occurred inside the device, and since there was a risk of the device corroding due to the condensation, the decontamination was stopped and the biological indicators were collected and cultured. In the comparative example, two biological indicators were negative, but one biological indicator was positive.

Figure 8 shows the changes in temperature, humidity, and peracetic acid concentration in the space to be decontaminated in the comparative example. As shown in Figure 8, in the comparative example, the relative humidity in the space to be decontaminated increased excessively.

100 Decontamination device, 110 First release section, 111 Container, 112 First decontamination agent, 113 Lid, 114, 115 Fan, 120 Second release section, 122 Second decontamination agent, 130 Control section, 200 Space, L1, L2 Solid lines, O1, O2 Openings.

Claims (3)

A decontamination apparatus configured to decontaminate a target space with peracetic acid,
A first emission section configured to emit a first gas resulting from a first decontamination agent;
A second emission section configured to emit a second gas resulting from the second decontamination agent;
A control unit configured to control the first emitter and the second emitter,
The concentration of peracetic acid in the second decontamination agent is higher than the concentration of peracetic acid in the first decontamination agent;
the control unit controls the first release unit to release the first gas until the following condition is satisfied, and controls the second release unit to intermittently release the second gas after the following condition is satisfied,
The following condition is that a first predetermined time has elapsed, which is the time it takes for the relative humidity in the target space to reach a humidity lower than the humidity at which condensation is likely to occur, or that the relative humidity in the target space reaches a predetermined value lower than the humidity at which condensation is likely to occur.
Decontamination equipment. The decontamination device according to claim 1, wherein the generation method of each of the first gas and the second gas is a mist generation method or a vaporization method. 3. The decontamination apparatus according to claim 1, wherein the control unit controls the first emission unit to emit the first gas until the relative humidity in the target space reaches the predetermined value, and controls the second emission unit to intermittently emit the second gas after the relative humidity reaches the predetermined value.