Safe cabinet

Abstract

The present invention efficiently sterilizes a safety cabinet. An indoor exhaust-type safety cabinet equipped with two fans, a clean air supply fan to a working chamber and an exhaust fan to a inside a clean room, wherein a sterilization mode changeover switch is provided or information of a sterilization mode can be input, and the output of the air supply fan is reduced in the sterilization mode in comparison to during normal operation.

Description

Biosafety cabinet

[0001] The present invention relates to a safety cabinet used in the development of pharmaceuticals, research on pathogens, and cell manipulation in regenerative medicine.

[0002] Safety cabinets are used when handling pathogens, such as in research on viruses and other pathogens, or in pharmaceutical development such as vaccine development, or for tasks such as cell observation and culture medium replacement in cell culture for regenerative medicine. Patent Document 1 (Patent Document 1) is an example of a safety cabinet. Patent Document 1 discloses a safety cabinet with an intake filter and an exhaust filter at the top of the workspace and an openable front shutter at the front of the workspace. Air flowing in through the front shutter opening and air passing through the intake filter pass through a slit at the front or rear of the workspace below, and is sucked in by a fan. The air pushed out by the fan passes through the intake or exhaust filter to purify the air.

[0003] Japanese Patent Application Laid-Open No. 2006-122816

[0004] Safety cabinets are used in a variety of fields. One example of their use is in the field of regenerative medicine, where cell culture is performed. In this field, preventing cross-contamination is particularly important.

[0005] Patent Document 1 discloses a surface sterilization method using ultraviolet light irradiation with a germicidal lamp installed in the working space of a safety cabinet, but does not consider sterilization of areas not exposed to ultraviolet light or sterilization including the air circulation path.

[0006] Therefore, an object of the present invention is to make it possible to efficiently sterilize a safety cabinet by introducing sterilizing gas used to sterilize a clean room into the safety cabinet.

[0007] This indoor exhaust type safety cabinet is equipped with two fans: a clean air supply fan to the work room and an exhaust fan to the inside of the clean room. It has a sterilization mode changeover switch or allows sterilization mode information to be input, and reduces the output of the air supply fan when in sterilization mode compared to normal operation.

[0008] According to the present invention, sterilizing gas is introduced into the safety cabinet during clean room sterilization, and the working space of the safety cabinet and the circulation exhaust path can be efficiently disinfected or sterilized.

[0009] Further means and effects of the present invention will become apparent throughout the entire specification below.

[0010] FIG. 1B is a front view of the safety cabinet of the present invention. FIG. 1C is a schematic cross-sectional explanatory view taken along line A-A in FIG. 1A. FIG. 1D is an explanatory view of the safety cabinet of the present invention during operation. FIG. 1E is an explanatory view showing control in the safety cabinet of the present invention. FIG. 1F is an example of a sterilization mode selector switch. FIG. 1G is an example of a sterilization mode selector switch. FIG. 1H is a diagram showing the safety cabinet and a clean room of the present invention. FIG. 1I is a diagram showing the safety cabinet and a clean room of the present invention.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings as needed.

[0012] 1A is a front view of the safety cabinet of the present invention. Reference numeral 100 denotes the safety cabinet. Reference numeral 10 denotes an upper housing, 11 denotes a side housing, 12 denotes a front housing, 13 denotes a lower housing, 20 denotes legs, and 21 denotes an upper duct.

[0013] A decorative cover 123 is provided. This includes both a case where it is formed integrally with the upper housing 10 and a case where it is formed integrally with the front shutter 103 made of transparent plastic or glass and is movable.

[0014] Reference numeral 104 denotes a working opening defined as the space between the front housing 12 and the underside of the front shutter 103 .

[0015] The safety cabinet of the present invention is of an indoor exhaust type, so that the exhaust air from the safety cabinet 100 is exhausted indoors as shown by exhaust air 114.

[0016] 1A is characterized by the inclusion of a sterilization mode changeover switch 124. The role of this sterilization mode changeover switch 124 will be described later.

[0017] Figure 1B is a schematic cross-sectional explanatory diagram taken along line A-A in Figure 1A. Since this diagram is intended to explain the concept of the invention, it omits some details and also depicts components that are not exactly in the intended location.

[0018] Inside the safety cabinet 100, a work space 102 is arranged, the front of which is constituted by a front shutter 103. The underside of the work space 102 is constituted by a work table 101, and a front slit 104a is arranged on the front shutter 103 side of the work table 101. A work opening 104 is formed below the front shutter 103. By operating the air supply fan 121, air drawn in by the air supply fan 121 passes through a blow-out HEPA filter 111, where it is purified, and then blown out downward. After being rectified by a blow-out rectifying plate 107, the air is supplied into the work space 102 as a blow-out airflow 113, forming an air barrier.

[0019] In FIG. 1B, the system further includes an exhaust fan 122. Air drawn in by the exhaust fan 122 passes through an exhaust HEPA filter 110 to be purified, and is then released into the room from an exhaust port 108 as exhaust air 114.

[0020] An amount of air equal to the air exhausted from the safety cabinet 100 into the room by the exhaust fan 122 is drawn in as an inflow airflow 112 from the work opening 104 below the front shutter 103. The inflow airflow 112 is sucked into the front slit 104a together with a portion of the blown airflow 113 from the work space 102. This air passes through the exhaust circulation path 117 below the work table 101 and is sucked in together with a portion of the blown airflow 113 from the rear slit 105a formed on the opposite side of the front shutter 103 of the work space 102. The air then passes through the rear path 105 and is sucked into the supply air fan 121 and exhaust fan 122 of the safety cabinet. As a result, the inflow airflow 112 from the work opening 104 is circulated or exhausted without stagnation in the work space 102, and acts as an air barrier for the inflow airflow 112 from the work opening 104.

[0021] One example of the use and purpose of the safety cabinet is to handle dust and aerosols containing pathogens, etc., in the work space 102. In such cases, dust and aerosols containing pathogens, etc., will also be present in the back path 105 and the upper chamber 109. When air is supplied to the work space 102 and when air is exhausted from the safety cabinet 100, this dust and aerosols are removed by the blow-out HEPA filter 111 and the exhaust HEPA filter 110.

[0022] FIG. 1C is a schematic explanatory view of the safety cabinet of the present invention when an operator is working.

[0023] A worker 118 sits in front of the safety cabinet 100, inserts his arm into the work space 102 through the work opening 104, and performs work while looking inside the work space 102 through the front shutter 103. At this time, brightness is ensured by illuminating the work space 102 with lighting from a lamp 115. In such a safety cabinet, the worker 118 uses the front shutter with an opening specified by the manufacturer, for example, a 200 mm opening.

[0024] When work is finished, the work table 101 is wiped clean with disinfectant ethanol or the like, the front shutter 103 is closed, and the germicidal lamp 116 is turned on for a certain period of time to sterilize the surface of the work table 101. However, surface sterilization by ultraviolet irradiation from the germicidal lamp 116 is insufficient for sterilizing areas not exposed to ultraviolet light, and for sterilizing and disinfecting the exhaust gas circulation path 117 as well.

[0025] Therefore, in order to achieve more powerful sterilization and disinfection, it is possible to install a hydrogen peroxide gas generator in the clean room when necessary and introduce the hydrogen peroxide gas generated from it into the safety cabinet 100, thereby enabling more powerful sterilization and disinfection of the safety cabinet 100.

[0026] 3 shows an example in which the safety cabinet 100 of the present invention is installed inside a clean room 400, and a hydrogen peroxide gas generator 900 is installed therein. Reference numeral 401 denotes a wall surface of a service room on the periphery of the clean room.

[0027] During indoor sterilization of the clean room 400, high-concentration hydrogen peroxide gas generated by the hydrogen peroxide gas generator 900 is drawn into the safety cabinet 100 as the inflow airflow 112 through the access opening 104 in the safety cabinet 100 shown in FIG. 1B. At this time, the drawn-in hydrogen peroxide gas passes through the front slits 104a and the like and is sucked into the air supply fan 121 or the exhaust fan 122. As a result, the inhaled hydrogen peroxide gas passes through the outlet HEPA filter 111 or the exhaust HEPA filter 110 one or more times as part of the air flow within the safety cabinet 100. This allows the hydrogen peroxide gas to be distributed throughout the entire safety cabinet 100, including the upper chamber 109.

[0028] Glass filter media may be used as an example of a HEPA filter medium. Filter media can also be referred to as "filter material." In particular, in this case, because the filter media adsorbs a small amount of hydrogen peroxide gas, the hydrogen peroxide gas concentration decreases each time it passes through the HEPA filter. This reduces sterilization efficiency and increases the sterilization time required. Furthermore, after sterilization, the hydrogen peroxide gas concentration must be reduced to a level that does not adversely affect the human body or the samples being handled. When air is circulated and passed through the HEPA filter, the hydrogen peroxide gas adsorbed on the filter media gradually re-emits, so it may take time to reduce the concentration to the desired level. For example, the entire sterilization process may need to be performed overnight.

[0029] Therefore, the present invention makes it possible to further reduce the time required for this series of sterilization steps. Here, the role of the sterilization mode changeover switch 124 described in Figure 1A will be explained.

[0030] The sterilization mode selector switch 124 is used to cause the safety cabinet 100 to perform an operation different from normal operation during sterilization work. The sterilization mode selector switch 124 enables the airflow rates of the air supply fan 121 and the exhaust fan 122 to be switched between normal operation and normal operation.

[0031] First, normal operation will be described. During normal use of the safety cabinet 100, approximately 70% of the air from the air supply fan 121 passes through the outlet HEPA filter 111, becomes the outlet airflow 113, and circulates through the work space 102. The remaining approximately 30% passes through the exhaust HEPA filter 110 by the exhaust fan 122 and is exhausted outside the safety cabinet 100 as exhaust air 114. The proportion of the total air volume that becomes circulating airflow is called the circulating air rate, and in the above case, the circulating air rate is approximately 70%. This corresponds to a Type A2 cabinet specified in JIS K 3800 for biohazard class 2 cabinets.

[0032] By turning on the sterilization mode changeover switch 124, the circulation air rate is changed to, for example, 30%.

[0033] That is, assume that exhaust air 114 is 70% and blown airflow 113 is 30%. Then, the increased amount of exhaust air 114 is taken into safety cabinet 100 as inflow airflow 112. As a result, during sterilization inside the clean room, the amount of hydrogen peroxide gas sucked in through access opening 104 below front shutter 103 and discharged from exhaust port 108 on the ceiling side increases, allowing the hydrogen peroxide gas to circulate rapidly from bottom to top.

[0034] Furthermore, a fan filter unit equipped with a HEPA filter is usually installed on the ceiling of the clean room, and circulates air from top to bottom within the clean room. The increase in exhaust air 114 also contributes to strengthening the circulation of air within the clean room.

[0035] Both of these measures will improve the air circulation efficiency throughout the clean room, preventing air from stagnating during indoor sterilization, which could prevent proper sterilization, and preventing hydrogen peroxide gas from settling and condensing on materials, which could lead to corrosion.

[0036] Furthermore, as a contribution to the clean room side, a safety cabinet having a function of agitating the sterilizing gas in the clean room can be provided.

[0037] In addition, a safety cabinet can be provided that promotes air circulation in the clean room by using the inflow airflow and exhaust air into the safety cabinet, thereby increasing the sterilization efficiency of the clean room and helping to sterilize equipment in the clean room in a short period of time.

[0038] 2A shows an example of the sterilization mode changeover switch 124. There are a sterilization selection button 240, a normal operation selection button 241, and a stop button 242, which are designed to be exclusively selected.

[0039] The sterilization mode changeover switch 124 may be configured as a physical switch or as a screen selection switch such as a touch panel.

[0040] The sterilization mode changeover switch 124 may be configured as one button for normal and stop, and another button for sterilization.

[0041] When the sterilization button is pressed or the sterilization mode is selected, it is desirable that the color of the button or display change, for example, to light up red, so that it can be easily confirmed that the device is in a special operating state that is different from normal.

[0042] Furthermore, it is desirable that the sterilization mode be given priority when selecting the mode, and that when the sterilization button is pressed or when the sterilization mode is selected, the operating state is forcibly switched to the sterilization mode.

[0043] 2B shows another example of the sterilization mode changeover switch 124. A toggle switch 250 is used to set the sterilization, stop, or normal mode.

[0044] Fig. 2C shows another example of the sterilization mode selector switch 124. In Fig. 2C, the entire sterilization mode selector switch 124 is configured as a touch panel. Each time the mode selection 260 is pressed, the operator can make settings while checking the operation mode information 261 displayed next to it, the selected mode information, etc.

[0045] In addition, the use of a touch panel makes it possible to register a large number of modes, which allows for mode registration more suited to the purpose of use and the situation. In Fig. 2C, the operation mode information 261 shows that the sterilization operation is selected as the operation mode, with the exhaust fan operating continuously and the intake fan operating intermittently.

[0046] Depending on the selection or setting made with the sterilization mode changeover switch 124, the actual operation of the exhaust fan and the air supply fan is changed.

[0047] Figure 1D is an explanatory diagram showing how the operation of the air supply fan 121 and the exhaust fan 122 is controlled based on instructions from the sterilization mode selector switch 124. Note that the control shown in Figure 1D is merely an example, and any control method or form in which the operation mode is ultimately changed by operating the sterilization mode selector switch 124 is included in the scope of this explanation.

[0048] Mode selection information 210 is transmitted to inverter controller 202. This transmission may be wireless or wired. Inverter controller 202 transmits an operation instruction for supply air fan 121 to supply air fan inverter 203, and transmits operation information for exhaust fan 122 to exhaust fan inverter 204. Supply air fan inverter 203 generates motor drive output 220 corresponding to the received operation information, and drives supply air fan motor 200, which drives supply air fan 121. Exhaust fan inverter 204 generates motor drive output 221 corresponding to the received operation information, and drives exhaust fan motor 201, which drives exhaust fan 122.

[0049] In FIG. 1D, the inverter controller 202 is illustrated as being separate from the sterilization mode selector switch 124, but the sterilization mode selector switch 124 may have the inverter controller 202 built in.

[0050] In addition, the air supply fan inverter 203 may be integrated with the air supply fan motor 200. In addition, the exhaust fan inverter 204 may be integrated with the exhaust fan motor 201.

[0051] The inverter controller 202 may be equipped with a PLC (programmable controller) and configured with a program.

[0052] The air volume may be changed by switching the fan output frequency by using the multi-speed operation function of the inverter 125 provided inside the decorative cover 123 and switching the contacts built into the inverter.

[0053] An example of control suitable for sterilization operation is to reduce the air circulation rate, as mentioned above. To achieve this, the rotation speed or inverter frequency of the air supply fan 121 is reduced, thereby reducing the air supply output from the air supply fan 121. This can also be achieved by increasing the rotation speed or inverter frequency or output of the exhaust fan 122. These may also be combined.

[0054] In addition, during sterilization operation, i.e., in sterilization mode, the frequency of the inverter output supplied to the air supply fan motor and the frequency of the inverter output supplied to the exhaust fan motor may be reversed from those during normal operation to reduce the air circulation rate.

[0055] Furthermore, during sterilization operation, i.e., in sterilization mode, the magnitude relationship between the output of the air supply fan and the output of the exhaust fan may be reversed from that during normal operation, thereby reducing the air circulation rate.

[0056] Instead of reducing the rotation speed or inverter frequency of the intake air fan 121, the effective circulation rate can be reduced by intermittent operation. In this case, a pulse wave can be formed in the circulating air inside the safety cabinet, rather than simply reducing the rotation speed or inverter frequency. This allows the hydrogen peroxide to attack contaminants adhering to the interior of the safety cabinet with a pressure wave, thereby quickly neutralizing the contaminants. Conversely, during diffusion operation, the pressure wave attack on the HEPA filter can promote the diffusion of hydrogen peroxide remaining in the HEPA filter. Note that control aimed at the pressure wave attack can be performed on the exhaust fan 122 instead of the intake air fan 121, or on both the intake air fan 121 and the exhaust fan 122.

[0057] Alternatively, in the early stages of the sterilization process, the circulation rate may be significantly reduced to actively introduce hydrogen peroxide gas from the clean room into the safety cabinet 100, and then the reduction in the circulation rate may be lessened to promote circulation within the safety cabinet 100. This is because the time that high-concentration hydrogen peroxide gas remains in the work space 102 will be longer, further improving the sterilization efficiency.

[0058] This embodiment is basically the same as embodiment 1. The difference is that the sterilization mode changeover switch 124 in embodiment 1 is installed outside the clean room 400 as shown in Figure 4, making it possible to switch the operation mode of the safety cabinet 100 by remote control from outside.

[0059] This eliminates the need for an operator to enter the clean room 400 to operate the device. Furthermore, it is possible to add an operation function for the hydrogen peroxide gas generator 900 to the sterilization mode selector switch 124, which allows for more efficient sterilization mode setting for the entire clean room.

[0060] This embodiment is basically the same as embodiment 2. The difference is that the function of the sterilization mode changeover switch 124 in embodiment 2 is incorporated into a smartphone device, a tablet device, or a remote monitoring system. This improves the flexibility and convenience of device operation.

[0061] The above examples illustrate the ideas and concepts of the present invention. Of course, the scope of the present invention also includes examples that are realized by combining the examples. Furthermore, as long as the disclosed ideas and concepts are used, any modifications or similar examples are also included within the scope of the present invention.

[0062] Furthermore, one example of the present invention described using the above embodiments can also be expressed as follows.

[0063] <1> An indoor exhaust type safety cabinet equipped with two fans, one for supplying clean air to the workroom and one for exhausting air to the inside of the clean room, which has a sterilization mode changeover switch or allows sterilization mode information to be input, and which reduces the output of the air supply fan when in sterilization mode compared to normal operation.

[0064] <2> The safety cabinet according to <1>, wherein the circulating air rate is reduced during the sterilization mode.

[0065] <No. 3> The safety cabinet according to <No. 2>, wherein the output of the exhaust fan is increased during the sterilization mode.

[0066] <Item 4> The safety cabinet according to item <Item 1>, wherein the frequency of the inverter output supplied to the motor of the air supply fan is reduced during the sterilization mode.

[0067] <No. 5> A safety cabinet according to <No. 1>, wherein, in the sterilization mode, the frequency of the inverter output supplied to the motor of the air supply fan and the frequency of the inverter output supplied to the motor of the exhaust fan are reversed from those in normal operation.

[0068] <No. 6> The safety cabinet according to <No. 2>, wherein the magnitude relationship between the output of the air supply fan and the output of the exhaust fan is reversed in the sterilization mode compared to normal operation.

[0069] <No. 7> The safety cabinet according to any one of <No. 1> to <No. 6>, wherein the sterilization mode selector switch allows selection of three modes: sterilization, normal, and stop.

[0070] <No. 8> In the safety cabinet according to <No. 7>, the sterilization mode changeover switch is configured as a touch panel.

[0071] <No. 9> The safety cabinet according to <No. 4> or <No. 5>, wherein the inverter is built into a decorative cover of the safety cabinet.

[0072] <Item 10> The safety cabinet according to any one of Items 1 to 6, wherein either the air supply fan or the exhaust fan is operated intermittently during the sterilization mode.

[0073] <No. 11> The safety cabinet according to <No. 2>, wherein the circulating air rate is significantly reduced in the early stage of the sterilization procedure, and the reduction in the circulating air rate is then alleviated.

[0074] <No. 12> The safety cabinet according to <No. 1>, wherein the safety cabinet receives the sterilization mode information from a sterilization mode changeover switch provided outside the clean room.

[0075] <No. 13> A sterilization system comprising the safety cabinet according to <No. 12>, wherein the sterilization mode changeover switch provided outside the clean room also has a function of issuing instructions to a hydrogen peroxide gas generator.

[0076] <No. 14> The safety cabinet according to <No. 1>, wherein the safety cabinet receives the sterilization mode information from a smartphone device, a tablet device, or a remote monitoring system.

[0077] DESCRIPTION OF SYMBOLS 10: Upper housing 11: Side housing 12: Front housing 13: Lower housing 20: Legs 21: Upper duct 100: Safety cabinet 101: Work table 102: Work space 103: Front shutter 104: Work opening 104a: Front slit 105: Rear path 105a: Rear slit 107: Blowout straightening plate 108: Exhaust port 109: Upper chamber 110: Exhaust HEPA filter 111: Blowout HEPA filter 112: Inlet airflow 113: Blowout airflow 114: Exhaust air 115: Light 116: Germicidal lamp 117: Exhaust circulation path 118: Operator 121: Intake air fan 122: Exhaust fan 123: Decorative cover 124: Sterilization mode selector switch 200: Intake air fan motor 201: Exhaust fan motor 202: Inverter controller 203: Inverter for air supply fan 204: Inverter for exhaust fan 210: Mode selection information 220, 221: Motor drive output 240: Sterilization selection button 241: Normal operation selection button 242: Stop button 250: Toggle switch 260: Mode selection area 261: Operation mode information 400: Clean room 401: Service room wall 900: Hydrogen peroxide gas generator

Claims

1. An indoor exhaust type safety cabinet equipped with two fans, one for supplying clean air to the work room and one for exhausting the air into the clean room, which has a sterilization mode changeover switch or allows sterilization mode information to be input, and which reduces the output of the air supply fan when in sterilization mode compared to normal operation.

2. A safety cabinet according to claim 1, wherein the air circulation rate is reduced during the sterilization mode.

3. A safety cabinet according to claim 2, wherein the output of the exhaust fan is increased during the sterilization mode.

4. A safety cabinet according to claim 1, wherein the frequency of the inverter output supplied to the motor of the air supply fan is reduced during the sterilization mode.

5. A safety cabinet according to claim 1, wherein, during the sterilization mode, the frequency of the inverter output supplied to the motor of the air supply fan and the frequency of the inverter output supplied to the motor of the exhaust fan are reversed from those during normal operation.

6. A safety cabinet according to claim 2, wherein the magnitude relationship between the output of the air supply fan and the output of the exhaust fan is reversed in the sterilization mode compared to normal operation.

7. A safety cabinet according to any one of claims 1 to 6, wherein the sterilization mode selector switch allows selection of three modes: sterilization, normal, and stop.

8. A safety cabinet according to claim 7, wherein the sterilization mode changeover switch is configured as a touch panel.

9. A safety cabinet according to claim 4 or 5, wherein the inverter is built into the decorative cover of the safety cabinet.

10. A safety cabinet according to any one of claims 1 to 6, wherein either the air supply fan or the exhaust fan is operated intermittently during the sterilization mode.

11. A safety cabinet as claimed in claim 2, in which the circulating air rate is significantly reduced in the early stage of the sterilization procedure, and the reduction in the circulating air rate is subsequently alleviated.

12. A safety cabinet according to claim 1, wherein the safety cabinet receives information about the sterilization mode from a sterilization mode changeover switch provided outside the clean room.

13. A sterilization system comprising the safety cabinet according to claim 12, wherein the sterilization mode changeover switch provided outside the clean room also has the function of issuing a command to a hydrogen peroxide gas generator.

14. The safety cabinet according to claim 1, wherein the safety cabinet receives the sterilization mode information from a smartphone device, a tablet device, or a remote monitoring system.

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