Biological safety cabinet

Abstract

The application belongs to the technical field of experimental equipment, and particularly relates to a biological safety cabinet. The application aims to solve the problems of large installation space and high cost caused by the need to configure two types of biological safety cabinets in the existing laboratory. The biological safety cabinet has three working modes, i.e., a first mode, a second mode and a third mode. The controller is configured to determine the target mode of the biological safety cabinet according to the mode selection instruction input by the user. The controller is further configured to control the biological safety cabinet to switch from the preset default mode to the target mode or from the current mode to the target mode. In this way, the biological safety cabinet has different working modes to adapt to different experimental requirements, thereby improving the application range of the biological safety cabinet. The laboratory does not need to configure two devices, which is conducive to reducing the installation space and reducing the cost. Moreover, the biological safety cabinet is provided with a default mode, and the switching mode is simpler and more effective, thereby avoiding the problem of gas overflow in the switching process.

Description

Technical Field

[0001] This application belongs to the field of experimental equipment technology, specifically relating to a biosafety cabinet. Background Technology

[0002] Biosafety cabinets are designed to protect the operator, the laboratory environment, and the experimental materials from exposure to infectious aerosols and splashes that may be generated during the handling of infectious experimental materials such as primary cultures, bacterial and viral strains, and diagnostic specimens.

[0003] Biosafety cabinets can be divided into three main categories: Class I, Class II, and Class III, to meet different biological research requirements. Among them, Class II biosafety cabinets are currently the most widely used type. In some Class II biosafety cabinets, clean air is recirculated and filtered after passing through the work area before being blown back into the work area; while in others, the clean air is exhausted to the outside after passing through the work area.

[0004] In related technologies, biosafety cabinets have a unidirectional airflow, requiring multiple types of biosafety cabinets to be configured in laboratories to meet the experimental requirements of different subjects. This not only requires a large installation space but also results in high costs. Summary of the Invention

[0005] In order to solve the above-mentioned problems in the existing technology, namely the problem that existing laboratories need to be equipped with multiple types of biosafety cabinets, resulting in large installation space and high costs.

[0006] This application provides a biosafety cabinet, including a cabinet body and a controller;

[0007] The cabinet encloses a working area with an opening on the front. The cabinet has a bottom air inlet at the bottom of the front side of the working area and an air outlet at the top of the working area. The top of the cabinet has a top air inlet and an air outlet, and the air outlet is connected to an indoor air outlet pipe and an outdoor air outlet pipe, respectively.

[0008] The cabinet contains a first air duct and a second air duct. The two ends of the first air duct are connected to the bottom air inlet and the air outlet, respectively. The two ends of the second air duct are connected to the top air inlet and the air outlet, respectively. A connecting opening is provided between the first air duct and the second air duct.

[0009] When the biosafety cabinet is in the first mode, the connection port is configured to be open, the indoor air outlet is configured to be open, the top air inlet is configured to be closed, and the outdoor air outlet is configured to be closed.

[0010] When the biosafety cabinet is in the second mode, the top air inlet is configured to be open, the outdoor air outlet is configured to be open, the connecting port is configured to be closed, and the indoor air outlet is configured to be closed.

[0011] When the biosafety cabinet is in the third mode, the connection port is configured to be open, the outdoor air outlet is configured to be open, the top air inlet is configured to be closed, and the indoor air outlet is configured to be closed.

[0012] The controller is configured to determine the target mode of the biosafety cabinet based on a mode selection command input by the user; the controller is also configured to switch from a preset default mode to the target mode, or switch from the current mode to the target mode; wherein the default mode is one of the first mode, the second mode, and the third mode, the target mode is different from the default mode, and the current mode is different from the target mode.

[0013] In the optional technical solutions for the above-mentioned biosafety cabinet, the default mode is the first mode.

[0014] In the optional technical solutions of the above-mentioned biosafety cabinet, a first fan is installed at the end of the second air duct near the air inlet; a second fan is installed at the end of the first air duct near the air outlet; an exhaust fan is installed in the outdoor air outlet duct; the controller is communicatively connected to the first fan, the second fan, and the exhaust fan respectively; when the biosafety cabinet is in the first mode, the first fan and the second fan are configured to start, and the exhaust fan is configured to stop; when the biosafety cabinet is in the second mode and the third mode, the first fan, the second fan, and the exhaust fan are configured to start.

[0015] In the optional technical solution of the above-mentioned biosafety cabinet, an electrically controlled door is installed at the front opening of the cabinet body, and the electrically controlled door is communicatively connected to the controller; the controller controls the electrically controlled door to open or close the front opening of the cabinet body.

[0016] In the optional technical solutions of the above-mentioned biosafety cabinet, the controller is configured to switch from the first mode to the target mode, or, when switching from the current mode to the target mode, sequentially control the first fan to turn off, control the electrically controlled door to close the front opening of the cabinet, and control the second fan to turn off.

[0017] In the optional technical solution of the above-mentioned biosafety cabinet, when the controller is configured to switch from the first mode to the second mode, the following steps are executed in sequence: the indoor air outlet duct is configured to be closed; the outdoor exhaust fan is configured to be started; after a first delay, the outdoor air outlet duct is configured to be open; after a second delay, the second fan is configured to be started; after a third delay, the top air inlet is configured to be opened; after a fourth delay, the first fan is configured to be started; the connecting port is configured to be closed; and the electrically controlled door is configured to open the front opening of the cabinet.

[0018] In the optional technical solutions of the above-mentioned biosafety cabinet, when the controller is configured to switch from the second mode to the first mode, the following steps are executed in sequence: the outdoor air outlet duct is configured to be closed; the external exhaust fan is configured to be closed; the top air inlet is configured to be closed; the connecting port is configured to be opened; the indoor air outlet duct is configured to be opened; the second fan is configured to be started; the electrically controlled door is configured to open the front opening of the cabinet; and the first fan is configured to be started.

[0019] In the optional technical solutions of the above-mentioned biosafety cabinet, when the controller is configured to switch from the first mode to the third mode, the following steps are executed in sequence: the indoor air outlet duct is configured to be closed; the outdoor exhaust fan is configured to be started; the outdoor air outlet duct is configured to be opened; the second fan is configured to be started; the electrically controlled door is configured to open the front opening of the cabinet; and the first fan is configured to be started.

[0020] In the optional technical solutions of the above-mentioned biosafety cabinet, when the controller is configured to switch from the third mode to the first mode, the following steps are executed in sequence: the outdoor air outlet duct is configured to be closed; the external exhaust fan is configured to be closed; the indoor air outlet duct is configured to be opened; the second fan is configured to be started; the electrically controlled door is configured to open the front opening of the cabinet; and the first fan is configured to be started.

[0021] In the optional technical solution of the above-mentioned biosafety cabinet, a first control valve is installed in the communication port. The first control valve is communicatively connected to the controller. When the controller controls the first control valve to open, the communication port opens; when the controller controls the first control valve to close, the communication port closes.

[0022] A second control valve is installed inside the top air inlet. The second control valve is communicatively connected to the controller. When the controller controls the second control valve to open, the top air inlet opens; when the controller controls the second control valve to close, the top air inlet closes.

[0023] A third control valve is installed inside the outdoor air outlet duct, and the third control valve is located between the exhaust fan and the air outlet; the third control valve is communicatively connected to the controller, and when the controller controls the third control valve to open, the outdoor air outlet duct is open; when the controller controls the third control valve to close, the outdoor air outlet duct is closed.

[0024] A fourth control valve is installed inside the indoor air outlet duct. The fourth control valve is communicatively connected to the controller. When the controller controls the fourth control valve to open, the indoor air outlet duct is open; when the controller controls the fourth control valve to close, the indoor air outlet duct is closed.

[0025] Those skilled in the art will understand that the biosafety cabinet in this embodiment includes a cabinet body and a controller. The cabinet body encloses a working area with a front opening. A bottom air inlet is located below the front of the working area for drawing in gas. An air outlet is located at the top of the working area for supplying gas into the area. The top of the cabinet body also has a top air inlet and an air outlet. The top air inlet draws in indoor gas, and the air outlet is connected to an indoor air outlet duct and an outdoor air outlet duct, respectively. The indoor air outlet duct exhausts air into the room, and the outdoor air outlet duct exhausts air to the outside. A first air duct and a second air duct are formed inside the cabinet. The two ends of the first air duct are connected to the bottom air inlet and the air outlet, respectively; the two ends of the second air duct are connected to the top air inlet and the air outlet, respectively. A connecting opening is provided between the first air duct and the second air duct.

[0026] When the biosafety cabinet is in its first mode, the connecting port is configured to be open, allowing the first and second air ducts to be connected; the indoor exhaust duct is configured to be open, the top air inlet is configured to be closed, and the outdoor exhaust duct is configured to be closed. Thus, a portion of the gas drawn in through the bottom air inlet enters the second air duct via the first air duct and the connecting port. The gas in the second air duct is then blown towards the work area through the air outlet. The remaining portion of the gas drawn in through the bottom air inlet is exhausted through the first air duct, the exhaust outlet, and the indoor exhaust duct. In this mode, the biosafety cabinet can be used for standard microbiological experiments, etc.

[0027] When the biosafety cabinet is in its second mode, the top air inlet is configured to be open, the outdoor air outlet is configured to be open, and the connecting port is configured to be closed, thus disconnecting the first and second air ducts; the indoor air outlet is configured to be closed. In this way, gas drawn in through the bottom air inlet enters the outdoor air outlet through the first air duct and the outlet, and is then discharged through the outdoor air outlet; gas drawn in through the top air inlet is blown into the work area through the second air duct and the air supply outlet. In this operating mode, all gas in the work area is discharged through the first air duct; it can be used in microbial experiments where volatile toxic chemicals and radioactive elements are used as auxiliary agents, and is safe and reliable.

[0028] In the third mode, the biosafety cabinet's connecting port is open, allowing the first and second air ducts to communicate; the outdoor exhaust duct is open, the top air inlet is closed, and the indoor exhaust duct is closed. Thus, a portion of the gas drawn in through the bottom air inlet enters the second air duct via the first air duct and connecting port. The gas in the second air duct is then blown towards the work area through the air outlet. The remaining gas drawn in through the bottom air inlet is exhausted outdoors through the first air duct, the exhaust duct, and the outdoor exhaust duct. In this mode, the biosafety cabinet can be used in microbiological experiments involving trace amounts of volatile toxic chemicals and radioactive elements as auxiliary agents. Compared to the second mode, the third mode consumes less power and is more energy-efficient.

[0029] The controller in this embodiment is configured to determine the target mode of the biosafety cabinet based on a mode selection command input by the user. Then, the controller is further configured to control the biosafety cabinet to switch from a preset default mode to the target mode, or from the current mode to the target mode. This allows the biosafety cabinet to have different operating modes to suit different experimental requirements, thus expanding its application range. The laboratory does not need to configure two devices, reducing installation space and costs. Furthermore, setting a default mode for the biosafety cabinet makes switching simpler and more effective, avoiding gas leakage problems during the switching process. Attached Figure Description

[0030] The following description, with reference to the accompanying drawings, outlines alternative embodiments of the biosafety cabinet of this application. The drawings are as follows:

[0031] Figure 1 This is a schematic diagram of the principle structure of the biosafety cabinet provided in the embodiments of this application;

[0032] Figure 2 This is a schematic diagram of the structure of the biosafety cabinet provided in the embodiments of this application;

[0033] Figure 3 This is an explosion diagram of the biosafety cabinet provided in the embodiments of this application;

[0034] Figure 4 This is a front view of the biosafety cabinet provided in the embodiments of this application;

[0035] Figure 5 yes Figure 4 Sectional view of AA;

[0036] Figure 6 This is a schematic diagram of the gas flow direction in the second mode of the biosafety cabinet provided in the embodiments of this application;

[0037] Figure 7 This is a schematic diagram of the gas flow direction in the first mode of the biosafety cabinet provided in this application embodiment;

[0038] Figure 8 This is a schematic diagram of the gas flow direction in the third mode of the biosafety cabinet provided in the embodiments of this application;

[0039] Figure 9 This is a schematic diagram of the exhaust connector of the biosafety cabinet provided in the embodiments of this application.

[0040] In the attached diagram: 100: Cabinet; 101: Working area; 102: Bottom air inlet; 103: Air outlet; 104: Top air inlet; 105: Air outlet; 110: First air duct; 111: Second fan; 112: Exhaust filter; 113: Bottom air duct; 114: Rear air duct; 120: Second air duct; 121: First fan; 122: Air supply filter; 130: Outer casing; 131: Outer panel; 132: Bottom plate; 133: Top plate; 134: Front cover; 135: Electrically controlled door; 1351: Door; 1352: Drive motor; 1353: Transmission component; 1354: Guide rail; 136: Water tray; 140: Workbench; 150: Inner side panel; 160: Partition; 161: Connecting port; 210: First control valve; 220: Second control valve; 230: Third control valve; 240: Fourth control valve; 300: Outdoor air outlet duct; 310: Outdoor exhaust fan; 400: Indoor air outlet duct; 500: Exhaust connector; 501: First interface; 502: Second interface; 503: Third interface; 510: Exhaust hood; 520: Pipe body; 600: Support leg. Detailed Implementation

[0041] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0042] Secondly, it should be noted that in the description of the embodiments of this application, the terms "inner" and "outer" and other terms indicating the direction or positional relationship are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of this application.

[0043] Furthermore, it should be noted that, in the description of the embodiments of this application, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0044] Biosafety cabinets are designed to protect the operator, the laboratory environment, and the experimental materials from exposure to infectious aerosols and splashes that may be generated during the handling of infectious experimental materials such as primary cultures, bacterial and viral strains, and diagnostic specimens.

[0045] Biosafety cabinets can be classified into three main categories: Class I, Class II, and Class III, to meet different biological research requirements. Among them, Class II biosafety cabinets are currently the most widely used type. In some Class II biosafety cabinets, clean air is recirculated and filtered before being blown back into the work area, such as in Class I cabinets; while in others, clean air is exhausted to the outside after passing through the work area, such as in Class II cabinets. In related technologies, laboratories often need to be equipped with both types of biosafety cabinets to suit the experimental requirements of different subjects. For example, Class I biosafety cabinets are usually chosen; while Class II cabinets are typically used for experiments that may release radioactive or toxic gases. This not only requires a larger installation space but also results in higher costs.

[0046] In view of this, this application provides a biosafety cabinet with three working modes, including a first mode, a second mode, and a third mode. The laboratory does not need to configure multiple devices, which helps to reduce the installation space occupied and reduce costs. In addition, the biosafety cabinet has a default mode, which makes the biosafety cabinet switch between the default mode and the target mode. The switching method is simpler and more effective, and avoids the problem of gas leakage during the switching process.

[0047] The optional technical solutions for the biosafety cabinets in the embodiments of this application are described below with reference to the accompanying drawings.

[0048] First, it should be noted that in this embodiment, the orientation is determined based on the installation location of the biosafety cabinet. The directional term "front" refers to the side of the biosafety cabinet with the front window, where the operator performs experiments on the workbench; the directional terms "back" and "behind" indicate the side away from the front window; the directional term "top" indicates the side away from the ground; and the directional term "bottom" indicates the side facing the ground. The Z-axis indicates the vertical direction.

[0049] Figure 1This is a schematic diagram of the principle structure of the biosafety cabinet provided in the embodiments of this application.

[0050] Reference Figure 1 The biosafety cabinet of this application embodiment includes a cabinet body 100 and support legs 600. An air duct is formed inside the cabinet body 100 to guide gas to the work area 101 or exhaust it to the outside of the cabinet body 100. The support legs 600 are used to support the cabinet body 100. Four support legs 600 can be provided and fixed to the four top corners of the bottom of the cabinet body 100 respectively. The bottom end of the support legs 600 can also be provided with casters to facilitate the movement of the biosafety cabinet.

[0051] In this embodiment, the cabinet 100 encloses a working area 101 with a front opening. The front opening of the cabinet 100 serves as the front window of the biosafety cabinet, through which the operator operates within the working area 101. A bottom air inlet 101 is provided below the front of the working area 101 for drawing in gas. An air outlet 103 is provided at the top of the working area 101 for supplying gas into the working area. The top of the cabinet 100 also has a top air inlet 104 and an air outlet 105. The top air inlet 104 draws in indoor gas, and the air outlet 105 discharges gas. The air outlet 105 is connected to an outdoor air outlet duct 300, which leads the gas discharged from the air outlet 105 to the outside. The air outlet 105 is also connected to an indoor air outlet duct 400, which leads the gas discharged from the air outlet 105 to the indoor environment.

[0052] The cabinet 100 contains a first air duct 110 and a second air duct 120. The two ends of the first air duct 110 are connected to a bottom air inlet 102 and an air outlet 105, respectively. Thus, air in the working area 101 enters the first air duct 110 through the bottom air inlet 102 and is discharged through the air outlet 105. The two ends of the second air duct 120 are connected to a top air inlet 104 and an air outlet 103, respectively. Thus, air drawn in by the top air inlet 104 enters the second air duct 120 and is delivered to the working area 101 through the air outlet 103. A connecting port 161 is provided between the first air duct 110 and the second air duct 120. When the connecting port 161 is open, the first air duct 110 and the second air duct 120 are connected; when the connecting port 161 is closed, the first air duct 110 and the second air duct 120 are disconnected.

[0053] Among some of the possible implementations, refer to Figure 1The first air duct 110 includes a bottom air duct 113 and a rear air duct 114 that are connected to each other. The bottom air duct 113 is located at the bottom of the working area 101, and the rear air duct 114 is located at the back of the working area 101. The front end of the bottom air duct 113 is connected to the bottom air inlet 102, and the rear air duct 114 is connected to the air outlet 105, thereby guiding the air entering from the front to the top. The second air duct 120 is located at the top of the working area 101, and the second air duct 120 is located in front of the rear air duct 114, which facilitates the formation of a downward airflow that blows towards the working area 101. Through the above arrangement, the first air duct 110 and the second air duct 120 inside the cabinet 100 have a compact structure.

[0054] The following is combined Figures 2 to 5 This describes a schematic diagram of the cabinet structure in an embodiment of this application. Wherein, Figure 2 This is a schematic diagram of the structure of the biosafety cabinet provided in the embodiments of this application;

[0055] Figure 3 This is an explosion diagram of the biosafety cabinet provided in the embodiments of this application; Figure 4 This is a front view of the biosafety cabinet provided in the embodiments of this application; Figure 5 yes Figure 4 Sectional view of AA.

[0056] Combination Figure 2 and Figure 3 The cabinet 100 in this embodiment includes: an outer shell 130, a workbench 140, an inner side panel 150, and a partition 160.

[0057] The outer casing 130 includes an outer side panel 131 with a front opening, a bottom plate 132, a top plate 133, and a front cover 134. The outer side panel 131 includes a back side plate and two side plates disposed on both sides of the back side plate. The bottom plate 132 and the top plate 133 are respectively fixed to the bottom and top of the outer side panel 131. The front cover 134 is fixed to the upper front side of the outer side panel 131 and is provided with control components such as an operation panel. The top air inlet 104 and the air outlet 105 are both disposed on the top plate 133 to facilitate air intake and exhaust. The bottom air inlet 102 is disposed on the bottom plate 132, for example, the bottom air inlet 102 is disposed on the front side of the bottom plate 132.

[0058] The workbench 140, inner side panel 150, and partition 160 are all installed inside the outer casing 130. The workbench 140 and inner side panel 150 enclose the working area 101. The workbench 140 and the base plate 132 are spaced apart to form a bottom air duct 113. A drip tray 136 is provided between the workbench 140 and the base plate 132 to collect condensate and other generated water.

[0059] The inner side panel 150 includes a rear side panel and two side panels disposed on both sides of the rear side panel. The rear side panel and the back side panel of the outer side panel 131 are spaced apart to form part of the back air duct 114.

[0060] A partition 160 is fixed between the inner side panel 150 and the top panel 133, and is fixedly connected to the top end of the inner side panel 150 and the top panel 133 respectively. A gap exists between the partition 160 and the back side panel of the outer side panel 131, forming part of the back air duct 114; a gap exists between the partition 160 and the front cover 134 to form a second air duct 120. A connecting port 161 connecting the first air duct 110 and the second air duct 120 is provided on the partition 160. The shape of the partition 160 is not limited in this embodiment, as long as sufficient space is provided for the second air duct 120 and the back air duct 114 to install a fan and a filter.

[0061] Thus, the back air duct 114 in this embodiment includes the gap between the partition 160 and the outer side panel 131, and the gap between the inner side panel 150 and the outer side panel 131.

[0062] Figure 9 This is a schematic diagram of the exhaust connector of the biosafety cabinet provided in the embodiments of this application, combined with... Figure 1 and Figure 9 The biosafety cabinet in this embodiment of the application also includes an exhaust connector 500, which provides installation space for the indoor exhaust duct 400 and the outdoor exhaust duct 300.

[0063] The exhaust connector 500 of this application embodiment has a first interface 501, a second interface 502 and a third interface 503. The first interface 501 is connected to the air outlet 105, the second interface 502 is connected to the outdoor air outlet 300, and the third interface 503 is connected to the indoor air outlet 400.

[0064] The exhaust connector 500 of this application embodiment includes an exhaust hood 510 and a pipe body 520, combined with Figure 3 The exhaust hood 510 can be a rectangular hood with an opening at the bottom, which is the first interface 501. The exhaust hood 510 is sealed and installed on the top plate 133 of the cabinet 100. The bottom end of the pipe body 520 is fixed to the top of the exhaust hood 510. The top of the pipe body 520 forms a second interface 502 and a third interface 503. The opening direction of the second interface 502 is vertical, which facilitates the connection of the outdoor air outlet pipe 300. The opening direction of the third interface 503 is perpendicular to the opening direction of the second interface 502, which facilitates the connection and arrangement of the pipe.

[0065] It should be noted that the structure of the cabinet 100 is not limited to the above structure, as long as it can form the air duct structure in the embodiment of this application.

[0066] In this embodiment, an electrically controlled door 135 is installed at the front opening of the cabinet 100, and the electrically controlled door 135 is located below the front cover 134. (Combined with...) Figure 3 The electrically controlled door 135 includes a door body 1351, a drive motor 1352, and a transmission component 1353. The door body 1351 is slidably mounted on the front sides of the two side panels of the outer perimeter panel 131. For example, a guide rail 1354 is provided on the front sides of the two side panels of the outer perimeter panel 131, and the door body 1351 is slidably mounted within the guide rail 1354. The door body 1351 can be a glass plate with good light transmission. The door body 1351 is connected to the drive motor 1352 via the transmission component 1353. Driven by the drive motor 1352, the door body 1351 slides along the guide rail 1354 to open or close the front opening of the cabinet 100. The drive motor 1352 can be installed on the top of the door body 1351 and is hidden inside the front cover 134. The output shaft of the drive motor 1352 is equipped with a transmission roller or transmission wheel, and the transmission component 1353 can be a transmission belt. One end of the transmission belt is fixed to the door body 1351, and the other end of the transmission belt is wound around the transmission roller or transmission wheel of the drive motor 1352. When the drive motor 1352 rotates, it drives the door body 1351 to slide along the guide rail 1354 through the transmission component 1353, thereby opening or closing the front opening of the cabinet 100.

[0067] The biosafety cabinet in this embodiment has three operating modes: a first mode, a second mode, and a third mode. The first mode is the A2 type biosafety cabinet operating mode, the second mode is the B2 type biosafety cabinet operating mode, and the third mode is the A2 exhaust operating mode. The following description, in conjunction with the appendix... Figure 6 and attached Figure 7 This application describes the flow direction of gas in the biosafety cabinet within the aforementioned air duct structure. Wherein, Figure 6 This is a schematic diagram of the gas flow direction in the second mode of the biosafety cabinet provided in the embodiments of this application; Figure 7 This is a schematic diagram of the gas flow direction in the first mode of the biosafety cabinet provided in this application embodiment; Figure 8 This is a schematic diagram of the gas flow in the third mode of the biosafety cabinet provided in this application embodiment. In the figure, arrow a, which is empty, represents clean gas; arrow b, which is filled, represents contaminated gas.

[0068] When the biosafety cabinet is in the second mode, combined with Figure 6The top air inlet 104 is configured to be open, the outdoor air outlet 300 is configured to be open, and the connecting port 161 is configured to be closed, so that the first air duct 110 and the second air duct 120 are configured to be disconnected; the indoor air outlet 400 is configured to be closed. Thus, the gas drawn in by the bottom air inlet 102 enters the outdoor air outlet 300 through the first air duct 110 and the air outlet 105, and is then discharged through the outdoor air outlet 300; the gas drawn in by the top air inlet 104 is blown towards the working area 101 through the second air duct 120 and the air supply outlet 103. In this working mode, all the gas in the working area 101 is discharged through the first air duct 110; it can be applied to microbial experiments where volatile toxic chemicals and radioactive elements are used as auxiliary agents, and is safe and reliable.

[0069] When the biosafety cabinet is in its first mode, combined with Figure 7 The connecting port 161 is configured to be open, allowing the first air duct 110 and the second air duct 120 to be connected; the indoor air outlet duct 400 is configured to be connected, the top air inlet 104 is configured to be closed, and the outdoor air outlet duct 300 is configured to be closed. Thus, a portion of the gas drawn in by the bottom air inlet 102 enters the second air duct 120 via the first air duct 110 and the connecting port 161. The gas in the second air duct 120 is then blown towards the working area 101 via the air outlet 103. The remaining portion of the gas drawn in by the bottom air inlet 102 is discharged via the first air duct 110, the air outlet 105, and the indoor air outlet duct 400. In this operating mode, 30% of the gas in the working area 101 is discharged through the air outlet 105, and 70% of the gas re-enters the working area 101 via the first air duct 110, the connecting port 161, the second air duct 120, and the air outlet 103, which can be applied to standard microbiological experiments, etc.

[0070] When the biosafety cabinet is in the third mode, combined with Figure 8 The connecting port 161 is configured to open, allowing the first air duct 110 and the second air duct 120 to be connected; the outdoor exhaust duct 300 is configured to be connected, the top air inlet 104 is configured to be closed, and the indoor exhaust duct 400 is configured to be closed. Thus, a portion of the gas drawn in through the bottom air inlet 102 enters the second air duct 120 via the first air duct 110 and the connecting port 161. The gas in the second air duct 120 is then blown towards the work area 101 through the air outlet 103. The remaining portion of the gas drawn in through the bottom air inlet 102 is exhausted to the outside via the first air duct 110, the air outlet 105, and the outdoor exhaust duct 300. In this mode, the biosafety cabinet can be used in microbiological experiments where trace amounts of volatile toxic chemicals and trace amounts of radioactive elements are used as auxiliary agents.

[0071] In the third mode, the gas in the working area 101 enters the first air duct 110. 70% of the gas in the first air duct 110 enters the second air duct 120 through the connecting port 161, and then re-enters the working area 101 through the air supply port 103. 30% of the gas in the first air duct 110 enters the outdoor air outlet duct 300 through the air outlet 105, and is discharged outdoors through the outdoor air outlet duct 300. The second mode has a large exhaust air volume, which results in a large make-up air volume in the laboratory, leading to high power consumption. Compared to the second mode, the third mode has lower power consumption and is more energy-efficient.

[0072] In order to achieve gas flow in the above three working modes, the biosafety cabinet in this application embodiment is provided with a first fan 121, a second fan 111 and an exhaust fan 310.

[0073] Combined again Figure 1 A first fan 121 is installed at one end of the second air duct 120 near the air outlet 103. The first fan 121 provides power for the gas to enter the working area 101 through the air outlet 103. An air filter 122 is installed between the first fan 121 and the air outlet 103 to filter the gas entering the working area 101. The first fan 121 is configured to start when the biosafety cabinet is in use. The first fan 121 is always activated during the use of the biosafety cabinet, meaning that the first fan 121 is activated in all three operating modes of the biosafety cabinet.

[0074] A second fan 111 is installed at one end of the first air duct 110 near the air outlet 105. The second fan 111 provides power for gas exhaust, especially when exhausting into the indoor air outlet duct 400. An exhaust filter 112 is installed between the second fan 111 and the air outlet 105 to filter the exhaust gas. The second fan 111 is configured to be activated when the biosafety cabinet is in use; that is, the second fan 111 is activated in all three operating modes of the biosafety cabinet.

[0075] An exhaust fan 310 is installed inside the outdoor air outlet duct 300 to provide power for exhausting air outdoors and to prevent outdoor air from flowing back into the biosafety cabinet.

[0076] In this embodiment, the controller is communicatively connected to the first fan 121, the second fan 111, and the exhaust fan 310 to control the starting and stopping of the fans. When the biosafety cabinet is in the first mode, the controller controls the first fan 121 and the second fan 111 to start and controls the exhaust fan 310 to stop; when the biosafety cabinet is in the second and third modes, the controller controls the first fan 121, the second fan 111, and the exhaust fan 310 to start.

[0077] Optionally, when the biosafety cabinet is operating in the second and third modes, the second fan 111 does not need to be started, and only the exhaust fan 310 is used to provide exhaust power. In the first mode, the second fan 111 must be started to prevent indoor air from flowing back into the biosafety cabinet through the air outlet 105.

[0078] To enable the opening and closing of the connection port 161, this embodiment of the application includes a first control valve 210 installed within the connection port 161 to control the opening and closing of the first air duct 110 and the second air duct 120. The first control valve 210 is communicatively connected to a controller. When the controller controls the first control valve 210 to open, the connection port 161 opens, connecting the first air duct 110 and the second air duct 120, allowing air from the second air duct 120 to enter the first air duct 110. When the controller controls the first control valve 210 to close, the connection port 161 closes, disconnecting the first air duct 110 and the second air duct 120.

[0079] To enable the opening and closing of the top air inlet 104, this embodiment of the application includes a second control valve 220 installed within the top air inlet 104. The second control valve 220 is configured to control the opening or closing of the top air inlet 104. The second control valve 220 is communicatively connected to a controller. When the controller controls the second control valve 220 to open, the top air inlet 104 opens, allowing indoor air to enter the second air duct 120 via the top air inlet 104; when the controller controls the second control valve 220 to close, the top air inlet 104 closes.

[0080] To enable the opening and closing of the outdoor air outlet duct 300, this embodiment of the application includes a third control valve 230 installed within the outdoor air outlet duct 300. The third control valve 230 is configured to control the opening or closing of the outdoor air outlet duct 300. The third control valve 230 is communicatively connected to a controller. When the controller controls the third control valve 230 to open, the outdoor air outlet duct 300 is open, allowing gas to be discharged outdoors; when the controller controls the third control valve 230 to close, the outdoor air outlet duct 300 is closed.

[0081] To enable the opening and closing of the indoor air outlet duct 400, this embodiment of the application includes a fourth control valve 240 installed within the indoor air outlet duct 400. The fourth control valve 240 is configured to control the opening or closing of the indoor air outlet duct 400. The fourth control valve 240 is communicatively connected to a controller. When the controller controls the fourth control valve 240 to be open, the indoor air outlet duct 400 is configured to be open, allowing gas to be discharged into the room; when the controller controls the fourth control valve 240 to be closed, the indoor air outlet duct 400 is configured to be closed.

[0082] It is understandable that the first control valve 210, the second control valve 220, the third control valve 230, and the fourth control valve 240 can be interpreted in a broad sense as valves that can control the opening and closing of pipelines, such as on / off valves and gate valves, or control switches such as electrically controlled doors that can control the opening and closing of pipelines.

[0083] Therefore, the biosafety cabinet in this embodiment controls the direction of gas flow in the air duct by controlling the opening and closing of the first control valve 210, the second control valve 220, the third control valve 230 and the fourth control valve 240, so that the biosafety cabinet can be formed in different types to suit different experimental requirements and improve the application range of the biosafety cabinet; the laboratory does not need to be equipped with two devices, which helps to reduce the installation space occupied and reduce costs.

[0084] Therefore, in this embodiment, the on / off states of the control valves and motors of the biosafety cabinet for the three operating modes are shown in Table 1:

[0085] Table 1

[0086]

[0087]

[0088] To implement the switching logic for the three operating modes, the biosafety cabinet in this embodiment of the application is equipped with a default mode, ensuring that the biosafety cabinet starts in the default mode every time it is used. The default mode is one of the first mode, the second mode, and the third mode. In this embodiment of the application, the default mode is the first mode. This setting makes switching between the three operating modes simple and efficient, and can avoid gas leakage during the switching process.

[0089] The controller in this embodiment is configured to determine the target mode of the biosafety cabinet based on a mode selection command input by the user. For example, the user can input the mode selection command by pressing a button; or, for another example, the user can input the mode selection command by touching a touch panel; or, for yet another example, the user can input the mode selection command by using a voice module.

[0090] The controller is also configured to control the biosafety cabinet to switch from a preset default mode to a target mode, which is different from the default mode; when the default mode is the first mode, the target mode can be the second mode or the third mode.

[0091] The controller is also configured to switch the biosafety cabinet from a current mode to a target mode, which is different from the target mode. The current mode can be any of the first, second, and third modes. For example, when the current mode is the second mode, the target mode can be either the first or third mode; as another example, when the current mode is the third mode, the target mode can be either the second or first mode.

[0092] The following describes the operating logic of each motor and control valve under the three modes of this application.

[0093] As shown in Table 1 above, in all three operating modes, the first fan 121, the second fan 111, and the exhaust fan 310 are all in the active state. Therefore, in this embodiment, when the biosafety cabinet switches modes, the controller sequentially controls the first fan 121 to shut down, controls the electrically controlled door 135 to close the front opening of the cabinet 100, and controls the second fan 111 to shut down. This configuration, by first shutting down the first fan 121, prevents airflow into the working area 101, thus maintaining a negative pressure state inside the biosafety cabinet. If the first fan 121 were to shut down with a delay, positive pressure might occur in the working area 101, leading to gas leakage. Shutting down the first fan 121 before closing the electrically controlled door 135 maintains the negative pressure inside the biosafety cabinet and prevents positive pressure from occurring.

[0094] To prevent gas leakage, the first fan 121 will immediately shut down in the event of a malfunction of the second fan 111 in the biosafety cabinet; otherwise, an alarm device will be triggered. Therefore, in this embodiment, the shutdown action of the second fan 111 is located after the shutdown action of the first fan 121, which can ensure that the second fan 111 continues to exhaust air after the first fan 121 is shut down, thus maintaining the negative pressure state inside the biosafety cabinet and preventing accidental triggering of the alarm device.

[0095] When the controller is configured to switch from the first mode to the second mode, the following steps are executed in sequence:

[0096] ① Control the first fan 121 to shut down → ② Control the electric door 135 to close the front opening of the cabinet 100 → ③ Control the second fan 111 to shut down → ④ Control the fourth control valve 240 to shut down, so that the indoor air outlet duct 400 is configured to be closed → ⑤ Control the exhaust fan 310 to start → ⑥ After a first delay, control the third control valve 230 to open, so that the outdoor air outlet duct 300 is configured to be open → ⑦ After a second delay, control the second fan 111 to start → ⑧ After a third delay, control the second control valve 220 to open, so that the top air inlet 104 is configured to be open → ⑨ After a fourth operation period, control the first fan 121 to start → ⑩ Control the first control valve 210 to close, so that the connecting port 161 is configured to be closed → Control the electric door 135 to open the front opening of the cabinet.

[0097] First, in the above steps, this application embodiment does not limit the first duration, second duration, third duration, and fourth duration. For example, the first duration, second duration, and third duration are 5 seconds, and the fourth duration is 3 minutes.

[0098] In the above steps, after shutting down the second fan 111 in step ③, it is in the static first mode, that is, the valve opening state is the same as in the first mode, but all fans are closed. In this embodiment, after shutting down the first fan 121 and the second fan 111, the fourth control valve 240 is closed to cut off the connection with the indoor environment. However, if the fourth control valve 240 is closed first and then the second fan 111 is shut down, the gas in the second fan 111 cannot be discharged, which may cause gas to exist between the fourth control valve 240 and the second fan 111, resulting in positive pressure and posing a risk of gas leakage.

[0099] After starting the exhaust fan 310 in step ⑤, the third control valve 230 is opened after a first delay. This is to discharge the gas in the pipe between the third control valve 230 and the exhaust fan 310, maintaining a negative pressure in the pipe. In step ⑦, after a second delay, the second fan 111 is opened to maintain a negative pressure in the channel between the second fan 111 and the third control valve 230. In step ⑧, after a third delay, the second control valve 220 is opened to discharge the gas in the channel between the second control valve 221 and the first fan 121, creating a negative pressure area between them. In step ⑨, after a fourth delay, the first fan 121 is started to ensure a negative pressure inside the biosafety cabinet before air is supplied to the work area 101. In this embodiment, after forming the static first mode, negative pressure is gradually generated from the outdoor exhaust pipe 300 to avoid gas overflow during the switching process.

[0100] In this embodiment, step ⑩, controlling the first control valve 210 to close, is to maintain a high negative pressure state in the area between the second control valve 220 and the first fan 121. If the first fan 121 is not started, the second fan 111 is running, and the first control valve 210 is closed, the second control valve 220 and the first fan 121 are connected to the outside through the top air inlet 104. The area between the first fan 121 and the top air inlet 104 is under slight negative pressure. At this time, the highest negative pressure is located at the air inlet of the second fan 111. The negative pressure gradually decreases from the air inlet of the second fan 111 to the working area 101 and then to the top air inlet 104. After the first fan 121 is started, the first control valve 210 is closed, and the area between the second control valve 220 and the first fan 121 can maintain a high negative pressure state.

[0101] When the controller is configured to switch from the second mode to the first mode, the following steps are executed in sequence:

[0102] ① Control the first fan 121 to shut down → ② Control the electrically controlled door 135 to close the front opening of the cabinet 100 → ③ Control the second fan 111 to shut down → ④ Control the third control valve 230 to shut down, so that the outdoor air outlet duct 300 is configured to be closed → ⑤ Control the exhaust fan 310 to shut down → ⑥ Control the second control valve 220 to shut down, so that the top air inlet 104 is configured to be closed → ⑦ Control the first control valve 210 to open, so that the connecting port 161 is configured to be open → ⑧ Control the fourth control valve 240 to open, so that the indoor air outlet duct 400 is configured to be open → ⑨ Control the second fan 111 to start → ⑩ Control the electrically controlled door 135 to open the front opening of the cabinet 100 → Control the start of the first fan 121.

[0103] In the above steps, since the biosafety cabinet is already under negative pressure due to operation in the second mode, no delay is required during the switching process.

[0104] In the above steps, the first fan 121 is turned off first, then the second fan 111 is turned off, and finally the exhaust fan 310 is turned off. This is because the first fan 121 delivers air and generates positive pressure, so it needs to be turned off first. Turning off the second fan 111 first and then the exhaust fan 310 is to avoid the problem of gas overflow caused by positive pressure between the second fan 111 and the exhaust fan 310.

[0105] In the above steps, after shutting down the exhaust fan 310 in step ⑤, a static second mode is formed. At this time, the power is off and the outdoor exhaust duct 300 is closed, and the opening states of other valves are the same as in the second mode. Then, after steps ⑥, ⑦, and ⑧, a static first mode is formed. At this time, the opening states of each valve are the same as in the first mode. In this switching process, switching from the dynamic second mode to the static second mode, then to the static first mode, and then back to the dynamic first mode is beneficial for airflow control and avoids the problem of airflow turbulence caused by directly switching from the dynamic second mode to the dynamic first mode.

[0106] In the above steps, the second fan 111 is started first, the electric control door 135 is opened, and then the first fan 121 is started. The purpose is to start the exhaust first and then start the supply air, that is, to form a negative pressure first and then supply air, which helps to avoid the problem of gas overflow.

[0107] When the controller is configured to switch from the first mode to the third mode, the following steps are executed in sequence:

[0108] ① Control the first fan 121 to close → ② Control the electric door 135 to close the front opening of the cabinet 100 → ③ Control the second fan 111 to close → ④ Control the fourth control valve 240 to close, so that the indoor air outlet duct 400 is configured to be closed → ⑤ Control the external exhaust fan 310 to start → ⑥ Control the third control valve 230 to open, so that the outdoor air outlet duct 300 is configured to be open → ⑦ Control the second fan 111 to start → ⑧ Control the electric door 135 to open the front opening of the cabinet 100 → ⑨ Control the first fan 121 to start.

[0109] In the above steps, after the second fan 111 is turned off in step ③, a static first mode is formed to avoid airflow turbulence during the switching process. In steps ⑤ and ⑥, the exhaust fan 310 is turned on first, followed by the third control valve 230, which helps to create negative pressure in the outdoor exhaust duct 300. In steps ⑦, ⑧ and ⑨, the second fan 111 is turned on first, followed by the electric control door 135, and finally the first fan 121 is turned on, ensuring that the gas in the working area 101 is discharged to the outside through the second fan 111, preventing the first fan 121 from sucking back the gas from the second fan 111 when the electric control door 135 is not opened.

[0110] When the controller is configured to switch from the third mode to the first mode, the following steps are executed in sequence:

[0111] ① Control the first fan 121 to close → ② Control the electric door 135 to close the front opening of the cabinet 100 → ③ Control the second fan 111 to close → ④ Control the third control valve 230 to close, so that the outdoor air outlet duct 300 is configured to be closed → ⑤ Control the exhaust fan 310 to close → ⑥ Control the fourth control valve 240 to open, so that the indoor air outlet duct 400 is configured to be open → ⑦ Control the second fan 111 to start → ⑧ Control the electric door 135 to open the front opening of the cabinet 100 → ⑨ Control the first fan 121 to start.

[0112] In the above steps, after the exhaust fan 310 is turned off in step ⑤, the static third mode is formed; after the fourth control valve 240 is opened in the process, the static first mode is formed. This setting facilitates the control of airflow during the switching process and avoids airflow turbulence.

[0113] In summary, the biosafety cabinet of this application embodiment includes a cabinet body 100 and a controller. The cabinet body 100 encloses a working area 101 with a front opening. A bottom air inlet 101 is provided on the lower front side of the working area 101 for drawing in gas. An air outlet 103 is provided on the top of the working area 101 for supplying gas into the working area 101. A top air inlet 104 and an air outlet 105 are provided on the top of the cabinet body 100. The top air inlet 104 is used to draw in indoor gas. The air outlet 105 is connected to an indoor air outlet 400 and an outdoor air outlet 300, respectively. The indoor air outlet 400 is used to exhaust air into the room, and the outdoor air outlet 300 is used to exhaust air to the outside.

[0114] The cabinet 100 forms a first air duct 110 and a second air duct 120. The two ends of the first air duct 110 are connected to the bottom air inlet 102 and the air outlet 105, respectively. The two ends of the second air duct 120 are connected to the top air inlet 104 and the air outlet 103, respectively. A connecting port 161 is provided between the first air duct 110 and the second air duct 120.

[0115] When the biosafety cabinet is in its first mode, the connection port 161 is configured to be open, allowing the first air duct 110 and the second air duct 120 to be connected; the indoor exhaust duct 400 is configured to be connected, the top air inlet 104 is configured to be closed, and the outdoor exhaust duct 300 is configured to be closed. Thus, a portion of the gas drawn in through the bottom air inlet 102 enters the second air duct 120 via the first air duct 110 and the connection port 161. The gas in the second air duct 120 is then blown towards the work area 101 through the air outlet 103. The remaining portion of the gas drawn in through the bottom air inlet 102 is exhausted through the first air duct 110, the air outlet 105, and the indoor exhaust duct 400. In this mode, the biosafety cabinet can be used for standard microbiological experiments, etc.

[0116] When the biosafety cabinet is in its second mode, the top air inlet 104 is configured to be open, the outdoor air outlet 300 is configured to be open, and the connecting port 161 is configured to be closed, thereby disconnecting the first air duct 110 and the second air duct 120; the indoor air outlet 400 is configured to be closed. Thus, the gas drawn in through the bottom air inlet 102 enters the outdoor air outlet 300 via the first air duct 110 and the air outlet 105, and is then discharged through the outdoor air outlet 300; the gas drawn in through the top air inlet 104 is blown towards the work area 101 via the second air duct 120 and the air supply outlet 103. In this operating mode, all gas in the work area 101 is discharged through the first air duct 110; this mode is suitable for microbial experiments involving volatile toxic chemicals and radioactive elements as auxiliary agents, and is safe and reliable.

[0117] In the third mode, the biosafety cabinet has the connecting port 161 open, allowing the first air duct 110 and the second air duct 120 to be connected; the outdoor exhaust duct 300 is connected, the top air inlet 104 is closed, and the indoor exhaust duct 400 is sealed. Thus, a portion of the gas drawn in through the bottom air inlet 102 enters the second air duct 120 via the first air duct 110 and the connecting port 161. The gas in the second air duct 120 is then blown towards the work area 101 through the air outlet 103. The remaining portion of the gas drawn in through the bottom air inlet 102 is exhausted to the outside via the first air duct 110, the air outlet 105, and the outdoor exhaust duct 300. In this mode, the biosafety cabinet can be used in microbiological experiments where trace amounts of volatile toxic chemicals and radioactive elements are used as auxiliary agents. Compared to the second mode, the third mode consumes less power and is more energy-efficient.

[0118] The controller in this embodiment is configured to determine the target mode of the biosafety cabinet based on a mode selection command input by the user. Then, the controller is further configured to control the biosafety cabinet to switch from a preset default mode to the target mode, or from the current mode to the target mode. This allows the biosafety cabinet to have different operating modes to suit different experimental requirements, thus expanding its application range. The laboratory does not need to configure two devices, reducing installation space and costs. Furthermore, setting a default mode for the biosafety cabinet makes switching simpler and more effective, avoiding gas leakage problems during the switching process.

[0119] The technical solutions of this application have been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of this application.

Claims

1. A biological safety cabinet, characterized by, The application relates to a biosafety cabinet, which comprises a cabinet body and a controller. The cabinet body encloses a working area with an open front side, and is provided with a bottom air inlet below the front side of the working area and an air outlet on the top of the working area; the top of the cabinet body is provided with a top air inlet and an air outlet, and the air outlet is respectively connected with an indoor air outlet pipe and an outdoor air outlet pipe. A first air duct and a second air duct are formed in the cabinet body, the two ends of the first air duct are respectively connected with the bottom air inlet and the air outlet, the two ends of the second air duct are respectively connected with the top air inlet and the air outlet, and a communication port is arranged between the first air duct and the second air duct. When the biosafety cabinet is in a first mode, the communication port is configured to be open, the indoor air outlet pipe is configured to be open, the top air inlet is configured to be closed, and the outdoor air outlet pipe is configured to be closed. When the biosafety cabinet is in a second mode, the top air inlet is configured to be open, the outdoor air outlet pipe is configured to be open, the communication port is configured to be closed, and the indoor air outlet pipe is configured to be closed. When the biosafety cabinet is in a third mode, the communication port is configured to be open, the outdoor air outlet pipe is configured to be open, the top air inlet is configured to be closed, and the indoor air outlet pipe is configured to be closed. The controller is configured to determine a target mode of the biosafety cabinet according to a mode selection instruction input by a user. The controller is further configured to switch from a preset default mode to the target mode or switch from a current mode to the target mode; wherein the default mode is one of the first mode, the second mode and the third mode, the target mode is different from the default mode, and the current mode is different from the target mode. A first fan is installed at one end of the second air duct close to the air outlet, a second fan is installed at one end of the first air duct close to the air outlet, and an outdoor exhaust fan is installed in the outdoor air outlet pipe. The controller is in communication connection with the first fan, the second fan and the outdoor exhaust fan. When the biosafety cabinet is in the first mode, the first fan and the second fan are configured to be started, and the outdoor exhaust fan is configured to be closed. When the biosafety cabinet is in the second mode and the third mode, the first fan, the second fan and the outdoor exhaust fan are configured to be started. An electric control door is installed on the front side opening of the cabinet body, and the electric control door is in communication connection with the controller. The controller controls the electric control door to open or close the front side opening of the cabinet body. When the controller is configured to switch from the first mode to the target mode or switch from the current mode to the target mode, the first fan is controlled to be closed, the electric control door is controlled to close the front side opening of the cabinet body, and the second fan is controlled to be closed. When the controller is configured to switch from the first mode to the second mode, the following steps are sequentially performed:

2. The biological safety cabinet of claim 1, wherein, ​ The indoor air outlet pipe is configured to be closed; the outdoor exhaust fan is configured to be started; after delaying for a first time length, the outdoor air outlet pipe is configured to be turned on; after delaying for a second time length, the second fan is configured to be started; after delaying for a third time length, the top air inlet is configured to be opened; after running for a fourth time length, the first fan is configured to be started; the communication port is configured to be closed; and the electric control door is configured to open the front side opening of the cabinet body.

3. The biological safety cabinet of claim 1, wherein, When the controller is configured to switch from the second mode to the first mode, the following steps are sequentially performed: The outdoor air outlet pipe is configured to be closed; the outdoor exhaust fan is configured to be closed; the top air inlet is configured to be closed; the communication port is configured to be opened; the indoor air outlet pipe is configured to be opened; the second fan is configured to be started; and the electric control door is configured to open the front side opening of the cabinet body. The first fan is configured to be started.

4. The biological safety cabinet of claim 1, wherein, When the controller is configured to switch from the first mode to the third mode, the following steps are sequentially performed: The indoor air outlet pipe is configured to be closed; the outdoor exhaust fan is configured to be started; the outdoor air outlet pipe is configured to be opened; the second fan is configured to be started; and the electric control door is configured to open the front side opening of the cabinet body. The first fan is configured to be started.

5. The biological safety cabinet of claim 1, wherein, When the controller is configured to switch from the third mode to the first mode, the following steps are sequentially performed: The outdoor air outlet pipe is configured to be closed; the outdoor exhaust fan is configured to be closed; the indoor air outlet pipe is configured to be opened; the second fan is configured to be started; and the electric control door is configured to open the front side opening of the cabinet body. The first fan is configured to be started.

6. The biological safety cabinet according to any one of claims 1-5, wherein, A first control valve is installed in the communication port, and the first control valve is in communication connection with the controller; when the controller controls the first control valve to be opened, the communication port is opened; and when the controller controls the first control valve to be closed, the communication port is closed. A second control valve is installed in the top air inlet, and the second control valve is in communication connection with the controller; when the controller controls the second control valve to be opened, the top air inlet is opened; and when the controller controls the second control valve to be closed, the top air inlet is closed. A third control valve is installed in the outdoor air outlet pipe, and the third control valve is located between the outdoor exhaust fan and the air outlet; the third control valve is in communication connection with the controller; when the controller controls the third control valve to be opened, the outdoor air outlet pipe is turned on; and when the controller controls the third control valve to be closed, the outdoor air outlet pipe is closed. A fourth control valve is installed in the indoor air outlet pipe, and the fourth control valve is in communication connection with the controller; when the controller controls the fourth control valve to be opened, the indoor air outlet pipe is turned on; and when the controller controls the fourth control valve to be closed, the indoor air outlet pipe is closed.

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