Safety cabinets and exhaust systems

Abstract

Provided is a technology that can prevent workers from being exposed to pollutants when an abnormality occurs in an air supply fan. The safety cabinet has an opening 60 for exhausting air from the work space 12, and is equipped with an exhaust duct 37 connected to the opening 60, a remote blower 33 for sending the air from the work space 12 to the outdoors through the exhaust duct 37, an air supply fan 14 for supplying air to the work space 12 from outside the safety cabinet 10, and a safety cabinet control unit 52 for transmitting an air volume control signal to the remote blower 33 when it detects that the air supply fan 14 has stopped operating.

Description

[Technical field]

[0001] The present invention relates to a safety cabinet and an exhaust system for use in industrial fields such as pharmaceuticals, medical care, and regenerative medicine. [Background technology]

[0002] In pharmaceutical development and research into pathogens such as viruses, safety cabinets are used to protect workers and samples. In safety cabinets, the air in the work space where contaminants are handled is filtered with a HEPA filter (High Efficiency Particulate Air Filter) to prevent contaminants from being discharged outside the equipment, and the air from which contaminants have been removed is exhausted outside the equipment.

[0003] In such safety cabinets, when handling large amounts of gaseous or volatile hazardous substances, the concentration of the hazardous substances will exceed the work environment standards if the exhaust is released into the laboratory. In addition, when handling substances that cannot be captured by HEPA filters or highly active substances such as anticancer drugs, it is dangerous to exhaust the exhaust into the laboratory.

[0004] For this reason, a remote fan is installed in the building in addition to the fan for the safety cabinet, and the safety cabinet exhaust is discharged outdoors through a direct duct connection that is connected to the remote fan with the safety cabinet sealed between the cabinet and the duct. The relevant regulations include the Industrial Safety and Health Act, the Offensive Odor Control Act, and the Air Pollution Control Act.

[0005] Patent Document 1 describes a direct duct connection technology in which a safety cabinet and a duct are sealed and connected to a remote blower. Patent Document 1 describes a method for inspecting an exhaust duct connection of a safety cabinet, in which the exhaust duct connection method is determined based on the output of a pressure detection means or an air volume detection means and the operating state of the blower means, and an alarm unit issues a warning if the exhaust duct connection method is inappropriate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-78527 A Summary of the Invention [Problem to be solved by the invention]

[0007] The above-mentioned Patent Document 1 describes that a warning is issued when the exhaust duct connection method is inappropriate, but if the air supply fan for supplying air to the work space of the safety cabinet stops abnormally, the building's remote blower continues to operate while maintaining a constant exhaust air volume, and the air volume equivalent to the air volume when the air supply fan is operating is added to the inflow air volume of the work opening. Therefore, the air volume in the work area below the work space becomes excessive, and there is a risk that the contaminant will fly up and contaminate the entire work space, especially when the contaminant being handled is a powder. Furthermore, there is a risk that the airborne contaminant will leak from the work opening and workers will be exposed to the contaminant.

[0008] An object of the present invention is to provide a technique capable of preventing exposure of workers to contaminants when an abnormality occurs in the supply air fan. [Means for solving the problem]

[0009] In order to solve the above problems, one representative safety cabinet of the present invention is a safety cabinet having an opening for exhausting air from the work space, and is equipped with an exhaust duct connected to the opening, a remote blower that sends the air in the work space from the exhaust duct to the outside, an intake fan that supplies air to the work space from outside the safety cabinet, and a control unit that sends an air volume control signal to the remote blower when it detects that the intake fan has stopped operating. Effect of the Invention

[0010] According to the present invention, when an abnormality occurs in the air supply fan, exposure of workers to contaminants can be prevented.

[0011] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a right side view showing an example of a schematic configuration of a safety cabinet. [Diagram 2] FIG. 11 is a right side view showing another example of the schematic configuration of the safety cabinet. [Diagram 3] FIG. 1 is a front view showing an example of the configuration of a safety cabinet according to a first embodiment. [Figure 4] FIG. 2 is a right side view showing an example of the configuration of the safety cabinet of the first embodiment. [Diagram 5] 4 is a flowchart showing an example of the operation of the safety cabinet of the first embodiment. [Figure 6] FIG. 11 is a front view showing an example of the configuration of a safety cabinet according to a second embodiment. [Figure 7] 10 is a flowchart showing an example of the operation of the safety cabinet of the second embodiment. [Figure 8] 13 is a flowchart showing an example of the operation of the safety cabinet of the third embodiment. [Figure 9] FIG. 13 is a diagram showing an example of a screen displayed on a display unit of a safety cabinet according to the third embodiment. [Figure 10] FIG. 11 is a right side view showing an example of the configuration of a safety cabinet according to a fourth embodiment. [Figure 11] 13 is a flowchart showing an example of the operation of the safety cabinet of the fourth embodiment. [Figure 12] FIG. 13 is a right side view showing an example of the configuration of a safety cabinet according to a fifth embodiment. [Figure 13] FIG. 23 is a right side view showing an example of the configuration of a safety cabinet according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments will be described with reference to the drawings.

[0014] However, the present invention should not be construed as being limited to the description of the following examples. It will be easily understood by those skilled in the art that the specific configurations can be modified without departing from the spirit or gist of the present invention.

[0015] In addition, in each drawing for explaining the embodiment, the same components are given the same names and symbols, and repeated explanations thereof may be omitted.

[0016] First, we will explain a safety cabinet equipped with two exhaust HEPA filters to detoxify contaminated air. When handling highly toxic substances in a safety cabinet, the contaminated air is passed through the exhaust HEPA filter twice, and the detoxified air is exhausted. By providing two exhaust HEPA filters, about 99% of the contaminants can be removed by passing the air through the first exhaust HEPA filter, and almost 100% of the contaminants can be removed by passing the air through the second exhaust HEPA filter.

[0017] FIG. 1 is a right side view showing an example of a schematic configuration of a safety cabinet.

[0018] 1, the safety cabinet 110 has inside thereof a work space 112 whose front side is constituted by a front shutter 113. An air supply fan 114 and an air supply HEPA filter 115 are provided at the upper part of the work space 112. The air supply fan 114 supplies clean air that has passed through the air supply HEPA filter 115 to the work space 112. A rear air flow path 130 is provided at the rear of the work space 112, and a pre-filter 119 is provided between the work space 112 and the rear air flow path 130.

[0019] A first exhaust HEPA filter 131 for exhaust is provided in the rear flow path 130, and a second exhaust HEPA filter 132 for exhaust is further provided in the building exhaust duct system and in the machine room. A remote blower 133 is provided above the safety cabinet 110.

[0020] The air supplied to the working space 112 from above and the air taken into the working space 112 from the working opening 117 pass through a prefilter 119 and flow through a rear flow passage 130, where contaminants 140 are removed by a first exhaust HEPA filter 131 and a second exhaust HEPA filter 132, and the air is exhausted to the outdoors by a remote blower 133. As shown in FIG. 2, two or more remote blowers may be provided.

[0021] FIG. 2 is a right side view showing another example of the schematic configuration of the safety cabinet.

[0022] The safety cabinet 110 in FIG. 2 differs from that in FIG. 1 in that it is equipped with two remote blowers, a remote blower 133 and a spare remote blower 134. In the case where one remote blower fails, this safety cabinet 110 can ensure a certain amount of exhaust air as long as the other remote blower continues to operate. However, when one remote blower stops, the exhaust air volume decreases, and the air barrier of the work opening 117 decreases, and there is a possibility that the contaminant 140 handled in the work space 112 may leak. Therefore, when one remote blower fails, the safety of the worker cannot be ensured, and the work must be stopped. EXAMPLES

[0023] 3 and 4 are diagrams showing an example of the configuration of the safety cabinet of Example 1, with Fig. 3 being a front view and Fig. 4 being a right side view. Note that in this example, an example of a safety cabinet provided with two HEPA filters for exhaust will be described, but the present invention is not limited to this.

[0024] As shown in FIG. 3, the safety cabinet 10 has, on the front side, a front shutter 13 that opens and closes vertically, and below the front shutter 13, a work opening 17 for performing work.

[0025] As shown in Fig. 4, the safety cabinet 10 is installed in a laboratory 55 in a building, and has a work space 12 inside, with an air supply fan 14 and an air supply HEPA filter 15 at the top of the work space 12. The air supply fan 14 takes in air from outside the safety cabinet 10, and supplies clean air that has passed through the air supply HEPA filter 15 to the work space 12. A worker 50 inserts his or her hands through a work opening 17 below the front shutter 13 to perform work in the work space 12.

[0026] The safety cabinet 10 is provided with a rear flow path 30 at the rear of the working space 12, and a pre-filter 19 is provided between the working space 12 and the rear flow path 30. The rear flow path 30 is provided with two exhaust HEPA filters 31 and 32.

[0027] The upper part of the safety cabinet 10 is provided with an opening 60 that exhausts the air that has passed through the two exhaust HEPA filters of the rear flow passage 30 to the outside of the safety cabinet 10, and the opening 60 is connected to a vertical flow passage 61. The vertical flow passage 61 is connected to an exhaust duct 37 via an electric valve 35. The electric valve 35 adjusts the amount of air passing through the exhaust duct 37. The exhaust duct 37 is provided with a remote blower 33 that sends air from the exhaust duct 37 to the outdoors.

[0028] The air supplied to the work space 12 from above and the air taken into the work space 12 from the work opening 17 pass through the prefilter 19 and flow through the rear flow path 30, where contaminants 40 are removed by the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32, and the air is exhausted to the outdoors through the exhaust duct 37.

[0029] The safety cabinet 10 also includes a safety cabinet control unit 52 that controls the operation of the air supply fan 14. The laboratory 55 is provided with a display unit 54 and a buzzer 58. The display unit 54 is configured with a liquid crystal monitor or the like, and displays the operating status of the air supply fan 14 and the remote blower 33, etc.

[0030] A processing unit 51 is installed in the control room of the building. The processing unit 51 constitutes an alarm system that notifies workers in the building of dangers such as exposure to contaminants by controlling and announcing displays 54 and buzzers 58 in the laboratory 55 shown in Fig. 4 as well as other laboratories throughout the building.

[0031] The safety cabinet control unit 52 , the display unit 54 , the buzzer 58 , the electric valve 35 , the remote blower 33 , and the arithmetic processing unit 51 are connected to each other via a control line 53 .

[0032] FIG. 5 is a flowchart illustrating an example of the operation of the safety cabinet according to the first embodiment.

[0033] 5, when the operation switch of the safety cabinet 10 is turned ON (step S101), a building exhaust start signal is sent from the safety cabinet control unit 52 to the remote blower 33 via the control line 53 (step S102). When the remote blower 33 receives the building exhaust start signal and starts operating, it sends a remote blower operation signal to the safety cabinet control unit 52.

[0034] The safety cabinet control unit 52 determines whether the remote blower operation signal has been turned ON (step S103). If the remote blower operation signal has not been turned ON (NO in step S103), the safety cabinet control unit 52 waits for the remote blower operation signal to be turned ON, and if a certain period of time has elapsed without the remote blower operation signal being turned ON (YES in step S104), the safety cabinet control unit 52 issues an alarm using the buzzer 58 (step S105), and returns to step S103.

[0035] When the remote blower operation signal is turned ON (YES in step S103), the safety cabinet control unit 52 starts operation of the air supply fan 14 after a certain time has elapsed (step S106), the safety cabinet 10 enters a normal operating state, and the operator 50 is ready to perform an experiment. The motorized valve 35 is always ON, and the damper is maintained in an open state.

[0036] To prevent positive pressure in the workspace 12 from causing contaminants 40 to escape outside the aircraft, the supply air fan 14 is interlocked to start operation after the remote blower 33 has started.

[0037] Next, the safety cabinet control unit 52 determines whether the operation switch of the safety cabinet 10 has been turned OFF (step S107), and if the operation switch of the safety cabinet 10 has been turned OFF, stops the operation of the air supply fan 14, stops the operation of the remote blower 33 after a certain period of time has elapsed, stops the operation of the safety cabinet 10, and terminates the processing.

[0038] To prevent positive pressure in the workspace 12 from causing contaminants 40 to escape outside the aircraft, the remote blower 33 is interlocked to shut down after the supply fan 14 has shut down.

[0039] On the other hand, if the operation switch of the safety cabinet 10 is not turned OFF (NO in step S107), the process proceeds to step S108.

[0040] In step S108, the safety cabinet control unit 52 determines whether the air supply fan operation signal is ON and monitors for an abnormal stop of the air supply fan 14. If the air supply fan 14 abnormally stops and the remote blower 33 continues to operate while maintaining a constant exhaust air volume, the amount of air flowing in from the work opening 17 becomes excessive. Therefore, the contaminant 40 will fly up into the work space 12, contaminating the work space 12, and there is a risk that the contaminant 40 will leak from the safety cabinet 10.

[0041] When the intake fan 14 stops abnormally and the intake fan operation signal is OFF (NO in step S108), the remote blower air volume control signal is turned ON (step S109) to prevent leakage of contaminants 40. In response to the remote blower air volume control signal being turned ON, the remote blower 33 is controlled to suppress its air volume. By suppressing the air volume of the remote blower 33, which corresponds to the air volume when the intake fan 14 is operating, an increase in the volume of air flowing in from the work opening 17 can be prevented.

[0042] At this time, the pressure in the exhaust duct 37 is monitored to determine whether the building exhaust airflow rate is an appropriate value (step S110). A sensor (not shown) detects the pressure in the exhaust duct 37. Based on the pressure detected by the sensor, the safety cabinet control unit 52 calculates the building exhaust airflow rate and determines whether it is an appropriate value. If the building exhaust airflow rate is higher than the appropriate value, the amount of air flowing in from the work opening 17 becomes excessive, causing contaminants 40 to fly up into the work space 12, contaminating the work space 12, and there is a risk that the contaminants 40 will leak from the safety cabinet 10. If the building exhaust airflow rate is lower than the appropriate value, the air barrier of the work opening 17 will be lowered, and there is a risk that the contaminants 40 will leak from the work opening 17.

[0043] When the building exhaust airflow rate is the appropriate value, the process returns to step S107, and the remote blower 33 continues to operate. On the other hand, when the step building exhaust airflow rate is not the appropriate value (NO in step S110), an alarm is issued by the buzzer 58 to call attention (step S111), and the process returns to step S107, and the remote blower 33 continues to operate.

[0044] In step S108, when the air supply fan operation signal is ON, the safety cabinet control unit 52 turns the remote blower air volume control signal OFF (step S112), returns to step S107, and continues operating the remote blower 33.

[0045] According to this embodiment, if the supply air fan 14 stops abnormally, the remote blower air volume control signal is turned ON to suppress the air volume of the remote blower 33, thereby preventing exposure of workers to pollutants. EXAMPLES

[0046] FIG. 6 is a front view illustrating an example of the configuration of the safety cabinet according to the second embodiment.

[0047] In the second embodiment, similarly to the first embodiment, the operating state of the remote blower 33 is changed by a command from the safety cabinet.

[0048] When an operator 50 uses the safety cabinet 10 for an experiment, the safety cabinet 10 must be used at a specified opening height set for the cabinet 10 in order to ensure an air barrier for the work opening 17. For this reason, an opening limit switch 56 is provided to monitor whether the front shutter 13 is set to the correct position.

[0049] On the other hand, even when the safety cabinet 10 is not in use, the remote blower 33 continues to operate so as to prevent leakage of contaminants 40 in the work space 12. At this time, a power-saving limit switch 57 is provided at a position where the opening height of the front shutter 13 is lower than when the safety cabinet is in use. When the safety cabinet control unit 52 receives a position information signal from the power-saving limit switch 57, it suppresses the air volume of the remote blower 33. This makes it possible to reduce power consumption when the safety cabinet 10 is not in use.

[0050] If the opening height of the front shutter 13 is lowered and the remote blower 33 continues to operate while maintaining a constant exhaust air volume, the amount of air flowing in from the work opening 17 will be excessive. As a result, contaminants 40 will fly up into the work space 12, contaminating the work space 12 and risk leaking from the safety cabinet 10. By suppressing the air volume of the remote blower 33, the exhaust air volume of the safety cabinet 10 can be maintained at an appropriate value, and exposure of the worker 50 to contaminants can be prevented.

[0051] FIG. 7 is a flowchart illustrating an example of the operation of the safety cabinet according to the second embodiment.

[0052] In FIG. 7, the same steps as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted. The safety cabinet control unit 52 determines whether the position information signal of the opening limit switch 56 or the power-saving limit switch 57 is ON and whether the front shutter 13 is set to the correct position (step S201). When neither the position information signal of the opening limit switch 56 nor the power-saving limit switch 57 is ON (NO in step S201), the process returns to step S107.

[0053] When the position information signal of opening limit switch 56 or power-saving limit switch 57 is ON (YES in step S201), it is determined whether the position information signal of power-saving limit switch 57 is ON (step S202).

[0054] When the position information signal of the power saving limit switch 57 is ON (YES in step S202), the remote blower air volume control signal is turned ON (step S203), and the process returns to step S107. In response to the remote blower air volume control signal being turned ON, the remote blower 33 is controlled to suppress the air volume.

[0055] If it is determined in step S108 that the position information signal of power saving limit switch 57 is not ON, the remote blower air volume control signal is turned OFF (step S204), and the process returns to step S107.

[0056] According to this embodiment, when the safety cabinet is not in use, the opening height of the front shutter 13 is lowered and the air volume of the remote-controlled blower 33 is controlled, thereby reducing power consumption and preventing workers from being exposed to contaminants. EXAMPLES

[0057] In this embodiment, an example will be described in which the fluctuation of the air barrier at the work opening 17 due to the fluctuation of the exhaust air volume of the safety cabinet 10 and the power supply to the safety cabinet 10 are monitored.

[0058] Fluctuations in the exhaust air volume may be a sign of a breakdown in the remote blower 33. Furthermore, an abnormality in the power supply to the safety cabinet 10 may cause the remote blower 33 to stop. By monitoring these, the safety of the work environment in the safety cabinet 10 can be confirmed, and when an abnormality occurs, the building's alarm system can notify the worker of the danger of the work environment. The alarm system is composed of an arithmetic processing device 51 and other components.

[0059] FIG. 8 is a flowchart illustrating an example of the operation of the safety cabinet according to the third embodiment.

[0060] In FIG. 8, the same steps as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

[0061] After the air supply fan 14 of the safety cabinet 10 starts operating, the safety cabinet control unit 52 determines whether the value indicating the operating status of the remote blower 33 satisfies a predetermined first judgment condition (step S301), and constantly monitors the operating status of the safety cabinet 10.

[0062] Here, the value indicating the operating state of the remote blower 33 includes a number of items such as exhaust air volume, voltage fluctuation, momentary power outage, or the state of an uninterruptible power supply (UPS) that supplies power to the safety cabinet 10 during a power outage. Note that instead of the exhaust air volume, the operating state of the remote blower 33 may be monitored by monitoring the exhaust HEPA filters 31, 32 or the pressure inside the exhaust duct 37.

[0063] A first judgment condition is set in advance for each of these multiple items, and when the value indicating the operating state satisfies the first judgment condition, it is judged that a minor abnormality has occurred in the operating state of the remote blower 33. An example of the first judgment condition is that the exhaust air volume is equal to or less than the lower limit of the exhaust air volume of the safety cabinet 10.

[0064] If the operating status of the remote blower 33, for example, a value indicating the exhaust air volume, satisfies the first judgment condition (YES in step S301), a warning signal is sent from the safety cabinet control unit 52 to the processing device 51 installed in the building's management room (step S302).

[0065] The calculation processing device 51 that receives the warning signal controls the display unit 54 installed in the safety cabinet 10 to display a screen such as that shown in FIG. 9, and warns the operator 50 by displaying, for example, messages such as “abnormal exhaust air volume” and “abnormal room pressure” in yellow.

[0066] Furthermore, the arithmetic processing device 51 controls the buzzer 58 installed in the safety cabinet 10 to sound, thereby alerting the operator 50.

[0067] Next, it is determined whether or not the value indicating the operating state of the safety cabinet 10 satisfies a predetermined second determination condition (step S303).

[0068] The second judgment condition is set in advance for each of a plurality of items of the operating state of the safety cabinet 10, and when the value indicating the operating state satisfies the second judgment condition, it is judged that a serious abnormality has occurred in the operating state of the remote blower 33. In this case, the worker 50 needs to evacuate from the laboratory 55. In addition, it is dangerous for the worker in the building to enter the laboratory 55.

[0069] If the value indicating the operating state of the safety cabinet 10 satisfies a predetermined second judgment condition (YES in step 303), the safety cabinet control unit 52 switches from the warning signal to an alarm signal and transmits it to the calculation processing device 51 (step S304).

[0070] In addition, when a value indicating the operating state of a predetermined number of the above-mentioned items, for example, two or more items, satisfies a first judgment condition, the attention signal may be switched to a warning signal. For example, when the exhaust air volume and the voltage fluctuation satisfy the first judgment condition, the attention signal may be switched to a warning signal.

[0071] Also, when the value indicating the operating state satisfies the first judgment condition for a predetermined period of time, the attention signal may be switched to the alarm signal. For example, when the exhaust air volume satisfies the first judgment condition for a predetermined period of time, the attention signal may be switched to the alarm signal.

[0072] The calculation processing device 51 that receives the alarm signal controls the display units 54 installed in each laboratory in the building to display a screen such as that shown in Figure 9, and urges workers in the building to evacuate by displaying, for example, messages such as "Power outage occurred" and "Emergency evacuation" in red.

[0073] In addition, the calculation processing device 11 controls the buzzers 58 installed in each laboratory in the building to sound at different tones and intervals than when a warning signal is received, thereby urging workers in the building to evacuate.

[0074] Furthermore, the arithmetic processing device 11 issues an alarm, for example by broadcasting it to the entire building, to advise people to avoid entering the laboratory 55.

[0075] By linking with the building's calculation device 51, an alarm can be sounded throughout the building. If a serious abnormality occurs in the operating condition of the remote blower 33, entry to the location where the safety cabinet 10 is installed can be restricted or workers can be urged to evacuate from the location where the safety cabinet 10 is installed.

[0076] Although the display unit 54 and the buzzer 58 are described as being installed in each laboratory in the building, they may be installed in other locations, such as a control room or a corridor.

[0077] According to this embodiment, a warning signal or alarm signal is sent to the building's processor 51 based on the value indicating the operating state of the remote blower 33, so that workers can be notified of the degree of danger in their work environment.

[0078] In addition, the calculation processing device 51 notifies the worker 50 in the safety cabinet 10 if a minor abnormality occurs in the operating status of the remote blower 33, and notifies all workers in the building if a serious abnormality occurs in the operating status of the remote blower 33, so that the workers can take action according to the level of danger in the work environment.

[0079] Furthermore, in one of the safety cabinets 10 in the building, when the safety cabinet control unit 52 detects that the above-mentioned first judgment condition is satisfied, it determines that a minor abnormality has occurred in the operating state of the remote blower 33, and transmits a warning signal to the alarm system. Upon receiving the warning signal, the alarm system notifies the operator 50 of the safety cabinet 10.

[0080] On the other hand, when the safety cabinet control unit 52 detects that the second judgment condition is satisfied in one of the safety cabinets 10 in the building, it determines that a serious abnormality has occurred in the operating state of the remote blower 33, and transmits an alarm signal to the alarm system. Upon receiving the alarm signal, the alarm system notifies all workers in the building.

[0081] This allows workers inside the building to take action according to the level of danger in their work environment.

[0082] The notification system may be configured to notify all workers in a building when it receives warning signals from a predetermined percentage of safety cabinets in the building.

[0083] In addition, by monitoring fluctuations in the power supply, momentary power outages, and the status of the uninterruptible power supply (UPS), it is possible to detect minute changes and abnormalities in the system's operating status, and by sending a signal to the arithmetic processing device 51, it is possible to notify the operator of the abnormality. EXAMPLES

[0084] In this embodiment, an example of a safety cabinet equipped with two exhaust ducts will be described.

[0085] FIG. 10 is a right side view illustrating an example of the configuration of the safety cabinet according to the fourth embodiment.

[0086] In Fig. 10, the same components as those in Fig. 4 are denoted by the same reference numerals, and the description thereof will be omitted. The safety cabinet 10 in Fig. 10 differs from that in Fig. 4 in that it includes two exhaust ducts, an exhaust duct 37 and a spare exhaust duct 38, which are provided in the building.

[0087] 10, the upper part of the safety cabinet 10 is provided with an exhaust duct 37 connected to the vertical flow path 61 via an electric valve 35, and a spare exhaust duct 38 branching from an opening 60 of the vertical flow path 61 to the motorized valve 35 and connected via a spare motorized valve 36. The spare motorized valve 36 adjusts the amount of air passing through the spare exhaust duct 38. The spare exhaust duct 38 is provided with a spare remote blower 34 that sends air from the spare exhaust duct 38 to the outdoors.

[0088] Normally, the motorized valve 35 is open, the remote blower 33 is operating, the standby motorized valve 36 is closed, and the standby remote blower 34 is stopped, so that the air in the working space 12 of the safety cabinet 10 is exhausted to the outdoors through the exhaust duct 37.

[0089] If the remote blower 33 stops abnormally, the backup electric valve 36 is opened, the backup remote blower 34 starts operating, and the electric valve 35 is closed, so that the air in the work space 12 is exhausted to the outdoors through the backup exhaust duct 38.

[0090] When the safety cabinet control unit 52 receives an abnormal stop signal for the remote blower 33, this can be achieved by sending a start signal for the backup remote blower 34, an open signal for the backup electric valve 36, and a close signal for the electric valve 35.

[0091] FIG. 11 is a flowchart illustrating an example of the operation of the safety cabinet according to the fourth embodiment.

[0092] In FIG. 11, the same components as those in FIG. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

[0093] Next, the safety cabinet control unit 52 determines whether the remote blower operation signal is ON (step S401) and monitors for an abnormal stop of the remote blower 33. If the remote blower 33 abnormally stops, exhaust to the outdoors becomes impossible, but if operation of the intake air fan 14 of the safety cabinet 10 continues, the clean air that has passed through the intake air HEPA filter 15 passes through the work space 12, contains the contaminants 40, and is blown out from the work opening 17 toward the worker 50, which may expose the worker 50 to the contaminants 40, which is dangerous.

[0094] In addition, if the remote blower 33 stops abnormally, stopping the operation of the air supply fan 14 of the safety cabinet 10 will cause the contaminants 40 in the work space 12 to float in the work space 12, and may leak through the work opening 17 into the laboratory 55 where the worker 50 is present.

[0095] In order to prevent exposure of the worker 50 to the contaminant 40, when the remote blower 33 stops abnormally and the remote blower operation signal is OFF (NO in step S401), the safety cabinet control unit 52 sends an operation stop signal to the remote blower 33 (step S402).

[0096] Next, the safety cabinet control unit 52 sends a close signal to the electric valve 35 to completely close the exhaust flow path of the exhaust duct 37 (step S403), and sends an open signal to the spare electric valve 36 to open the exhaust flow path of the spare exhaust duct 38 (step S404).

[0097] Furthermore, the safety cabinet control unit 52 transmits a start signal to the spare remote blower to start operation of the spare remote blower (step S405), and switches the exhaust flow path from the exhaust duct 37 to the spare exhaust duct .

[0098] As a result, contaminants 40 in the work space 12 pass through the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32, and are exhausted to the outdoors through the auxiliary exhaust duct 38, so that they do not become suspended in the work space 12 and there is no possibility of them leaking through the work opening 17 into the laboratory 55 where the workers 50 are present.

[0099] Next, the safety cabinet control unit 52 controls the display unit 54 to display information to inform the operator 50 in the laboratory 55 that the remote blower 33 has stopped abnormally and the auxiliary exhaust duct 38 is being used (step S406), and then returns to step S107. Note that the buzzer 58 provided in the laboratory 55 may be sounded to inform the operator 50 that the remote blower 33 has stopped abnormally.

[0100] According to this embodiment, even if the remote blower 33 stops abnormally, the necessary exhaust air volume of the safety cabinet 10 can be maintained, and exposure of workers to contaminants can be prevented.

[0101] In addition, if the remote blower 33 stops abnormally, the electric valve 35 is closed and removed from the exhaust flow path of the safety cabinet 10, so that fault diagnosis and maintenance work on the remote blower 33 can be performed even when the safety cabinet 10 is in operation and in use.

[0102] Furthermore, the spare exhaust duct 38 is provided branching off between the opening 60 of the vertical flow path 61 and the motorized valve 35 so that the distance of the exhaust flow path from the opening 60 to the spare motorized valve 36 is shorter than the distance of the exhaust flow path from the opening 60 to the motorized valve 35. Therefore, if the remote blower 33 abnormally stops, the exhaust flow path can be switched from the exhaust duct 37 to the spare exhaust duct 38 in a short time due to the abnormal stop of the remote blower 33, and disturbance of the air barrier at the work opening 17 of the safety cabinet 10 can be prevented, thereby preventing leakage of contaminants. EXAMPLES

[0103] FIG. 12 is a right side view showing an example of the configuration of the safety cabinet of the fifth embodiment.

[0104] Example 5 differs from Example 4 in FIG. 10 in that a spare exhaust duct 38, a spare remote blower 34, and a spare electric valve 36 are arranged between the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32.

[0105] 12, the safety cabinet 10 has an opening 62 for exhausting air to the outside of the safety cabinet 10 between the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32 of the rear flow path 30. The opening 62 is connected to the auxiliary exhaust duct 38 via the auxiliary motorized valve 36.

[0106] As in the fourth embodiment, when the remote blower 33 abnormally stops and the remote blower operation signal is OFF, the safety cabinet control unit 52 provided in each of the multiple safety cabinets 10 sends a close signal to the motorized valve 35 to fully close the exhaust flow path of the exhaust duct 37, and sends an open signal to the spare motorized valve 36 to open the exhaust flow path of the spare exhaust duct 38. The safety cabinet control unit 52 sends a start signal to the spare remote blower 34 to start operation of the spare remote blower 34, and switches the exhaust flow path from the exhaust duct 37 to each spare exhaust duct 38.

[0107] At least one of the safety cabinet control units 52 included in each of the multiple safety cabinets 10 may transmit each signal.

[0108] According to this embodiment, if the remote blower 33 stops abnormally, the exhaust flow path is switched from the exhaust duct 37 to each auxiliary exhaust duct 38, so that the required exhaust volume of the safety cabinet 10 can be maintained and exposure of workers to contaminants can be prevented.

[0109] Also, an opening 62 is provided between the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32 in the rear flow path 30, and the auxiliary exhaust duct 38 is connected to the opening 62, so that the distance of the exhaust flow path from the pre-filter 19 to the auxiliary motorized valve 36 is shorter than the distance of the exhaust flow path from the pre-filter 19 to the motorized valve 35. Therefore, if the remote blower 33 abnormally stops, the exhaust flow path can be switched from the exhaust duct 37 to the auxiliary exhaust duct 38 in a shorter time, and disturbance of the air barrier at the work opening 17 of the safety cabinet 10 can be prevented, thereby preventing leakage of contaminants.

[0110] Furthermore, according to this embodiment, an opening 62 is provided between the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32 in the rear flow passage 30, and the preliminary exhaust duct 38 is connected to the opening 62, so that the exhaust air from the preliminary exhaust duct 38 does not pass through the second exhaust HEPA filter 32. Therefore, exhaust resistance is reduced compared to when the exhaust air passes through two exhaust HEPA filters, and the rated output of the preliminary remote blower 34 can be reduced, thereby reducing power consumption.

[0111] Although the opening 62 is disposed between the first exhaust HEPA filter 31 and the second exhaust HEPA filter 32 in the rear flow passage 30, the number of exhaust HEPA filters and the position of the opening 62 are not limited to this. The opening 62 only needs to be disposed so as to exhaust air that has passed through at least one exhaust HEPA filter. EXAMPLES

[0112] In this embodiment, an example in which exhaust flow paths of a plurality of safety cabinets are collectively connected to one exhaust duct will be described.

[0113] FIG. 13 is a right side view showing an example of the configuration of the safety cabinet of the sixth embodiment.

[0114] As shown in FIG. 13, the openings 60 of the safety cabinets 10 are each connected to a vertical flow path 61, and each vertical flow path 61 is connected to one exhaust duct 37 via an electric valve 35.

[0115] Each of the safety cabinets 10 is provided with a spare exhaust duct 38 that branches off between the opening 60 of the vertical flow path 61 and the motorized valve 35 and is connected via a spare motorized valve 36. The spare motorized valve 36 adjusts the amount of air passing through the spare exhaust duct 38. The spare exhaust duct 38 is provided with a spare remote blower 34 that sends air from the spare exhaust duct 38 to the outdoors.

[0116] When the remote blower 33 abnormally stops and the remote blower operation signal is OFF, the safety cabinet control unit 52 provided in each of the multiple safety cabinets 10 sends a close signal to the motorized valve 35 to fully close the exhaust flow path of the exhaust duct 37, and sends an open signal to the spare motorized valve 36 to open the exhaust flow path of the spare exhaust duct 38. The safety cabinet control unit 52 sends a start signal to the spare remote blower 34 to start operation of the spare remote blower 34, and switches the exhaust flow path from the exhaust duct 37 to each spare exhaust duct 38.

[0117] When multiple safety cabinets are connected to one exhaust duct, the operation of multiple safety cabinets 10 must be stopped collectively because the stop of operation of one safety cabinet 10 causes fluctuations in the exhaust air volume of the other safety cabinets 10, causing disturbances in the air barrier of the work opening 17. If one safety cabinet abnormally stops, the exhaust flow path can be switched from the exhaust duct 37 to the spare exhaust duct 38 to prevent disturbances in the air barrier of the work opening 17.

[0118] According to the sixth embodiment, even if the remote blower 33 stops abnormally, the necessary exhaust volume of the safety cabinet 10 can be maintained, and exposure of workers to contaminants can be prevented. In addition, since a plurality of safety cabinets 10 share one exhaust duct 37, the safety cabinets can be manufactured at low cost.

[0119] In FIG. 13, the spare exhaust ducts 38 are arranged directly above each safety cabinet 10, and each is equipped with a spare electric valve 36 and a spare remote blower 34, but multiple spare exhaust ducts 38 can also be connected together to form a single system.

[0120] In this case, the number of pre-exhaust ducts can be reduced to one, which allows for further cost reduction in production.

[0121] In each of the above embodiments, a total exhaust type safety cabinet has been described in which air taken in from outside is passed through the work space, contaminants are removed using a HEPA filter, and all of the air is exhausted to the outside. However, the present invention can also be used in a circulation type safety cabinet in which part of the exhaust air is returned to the work space to circulate the air.

[0122] The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0123] 10. Biosafety Cabinet 13 Full Shutter 14 Air supply fan 33 Remote Blower 37 Exhaust Duct 52 Safety Cabinet Control Section 56 Opening limit switch 57 Energy saving limit switch

Claims

1. In a safety cabinet having an opening for exhausting air from a working space, an exhaust duct connected to the opening; a remote blower that blows the air in the working space to the outside through the exhaust duct; an air supply fan for supplying air from the outside of the safety cabinet to the working space; a control unit that transmits an air volume control signal to the remote blower when the control unit detects that the supply air fan has stopped operating; a sensor for detecting a pressure in the exhaust duct; The control unit is If the pressure in the exhaust duct is at an appropriate value after transmitting the air volume control signal, the operation is continued; A safety cabinet that issues an alarm if the pressure in the exhaust duct is not at an appropriate value after the air volume control signal is sent.

2. 2. The safety cabinet according to claim 1, A safety cabinet in which the remote blower changes the air volume based on an air volume control signal transmitted from the control unit.

3. The safety cabinet according to claim 2, A safety cabinet in which, when the remote blower receives the air volume control signal, it reduces the air volume to a volume equivalent to the air volume when the air supply fan is operating.

4. A safety cabinet having an opening for exhausting air from a working space; an exhaust duct connected to the opening; a remote blower that blows the air in the working space to the outside through the exhaust duct; A sensor for detecting a pressure in the exhaust duct; In an exhaust system comprising: The safety cabinet comprises: an air supply fan for supplying air from the outside of the safety cabinet to the working space; a control unit that transmits an air volume control signal to the remote blower when the control unit detects that the supply air fan has stopped operating; The remote blower changes the air volume based on a signal transmitted from the control unit, The control unit is If the pressure in the exhaust duct is at an appropriate value after transmitting the air volume control signal, the operation is continued; The exhaust system issues an alarm if the pressure in the exhaust duct is not at an appropriate value after the air volume control signal is sent.

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