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 that the existing biological safety cabinet has unstable falling air speed and cannot meet the falling air speed standard. The biological safety cabinet is provided with a first control valve at a communication port of a first air duct and a second air duct. When the working voltage of a supply air unit is greater than or equal to a preset first voltage threshold, the first control valve is configured to be opened to the maximum opening. The working voltage of the supply air unit is adjusted, and the rotating speed of the supply air unit is adjusted. When the working voltage of the supply air unit is less than the first voltage threshold, the supply air unit is configured to operate according to the first voltage. The opening and closing angle of the first control valve is adjusted, and the first air speed of the biological safety cabinet is adjusted. The first air speed of the biological safety cabinet is adjusted by combining the two modes of adjusting the supply air unit and adjusting the opening and closing angle of the first control valve, so that excessive noise of the biological safety cabinet is avoided.

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 are equipped with air supply fans to direct air downwards into the work area, and the airflow speed is controlled by adjusting the fan's rotation speed. For AC fans, higher noise levels are generated when the operating voltage is below a set value. Therefore, biosafety cabinet air supply fans are typically set with a minimum operating voltage to ensure that the fan noise meets the noise requirements of the biosafety cabinet.

[0004] However, such a setting can easily lead to excessively high descent wind speeds, resulting in unstable descent wind speeds that fail to meet the descent wind speed standards. Summary of the Invention

[0005] In order to solve the above-mentioned problems in the existing technology, namely the problem that the descent air velocity of the existing biosafety cabinet is unstable and cannot meet the descent air velocity standard.

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

[0007] The cabinet encloses a working area with an opening at the front. A bottom air inlet is located below the front of the working area, and an air outlet is located at the top of the working area. An air outlet is located at the top of the cabinet. A first wind speed sensor is installed within the working area to detect the wind speed blowing from the air outlet towards the working area. A first air duct and a second air duct are formed within the cabinet. The two ends of the first air duct are connected to the bottom air inlet and the air outlet, respectively. The second air duct is connected to the air outlet. A connecting port is provided between the second air duct and the first air duct, and a first control valve is installed within the connecting port. The first control valve is configured to open or close the connecting port. The aforementioned connection port allows the first air duct and the second air duct to be connected or disconnected; an air supply unit is installed at one end of the second air duct near the air outlet, the air supply unit including an air supply fan, the air supply unit being configured to determine the operating voltage of the air supply unit according to the first wind speed when the operating voltage of the air supply unit is greater than or equal to a preset first voltage threshold, and the first control valve being configured to open to its maximum opening; when the operating voltage of the air supply unit is less than the first voltage threshold, the air supply unit is configured to operate according to the first voltage, and the first control valve is configured to determine the opening angle of the first control valve according to the first wind speed, wherein the first voltage is greater than or equal to the first voltage threshold.

[0008] In the optional technical solution of the above-mentioned biosafety cabinet, a plurality of communication ports are arranged at intervals along the length of the cabinet body, and each communication port is provided with a first control valve; a plurality of first wind speed sensors are arranged at intervals along the length of the cabinet body in the working area, and the number of first wind speed sensors is the same as the number of first control valves, and each first wind speed sensor corresponds to one of the first control valves; the first control valve is configured to determine the opening and closing angle of the first control valve according to the first wind speed detected by the corresponding first wind speed sensor when the operating voltage of the air supply unit is less than the first voltage threshold.

[0009] In the optional technical solution of the above-mentioned biosafety cabinet, there are two air supply units, which are arranged at intervals along the length of the cabinet body; two communication ports are arranged at intervals along the length of the cabinet body, and each communication port is provided with a first control valve; there are two first wind speed sensors, and the two first wind speed sensors correspond to the two first control valves respectively, and the two first wind speed sensors correspond to the two air supply units respectively; the air supply unit is configured to determine the operating voltage of the air supply unit according to the first wind speed detected by its corresponding first wind speed sensor when the operating voltage of the air supply unit is greater than or equal to the first voltage threshold.

[0010] In the above-mentioned optional technical solutions for biosafety cabinets, when the first wind speed is less than the preset first target wind speed, the opening and closing angle of the first control valve increases; when the first wind speed is greater than the first target wind speed, the opening and closing angle of the first control valve decreases.

[0011] In the optional technical solutions of the above-mentioned biosafety cabinet, when the first wind speed is less than the preset first target wind speed, the operating voltage of the air supply unit increases; when the first wind speed is greater than the first target wind speed, the operating voltage of the air supply unit decreases.

[0012] In the optional technical solution of the above-mentioned biosafety cabinet, a partition is provided between the first air duct and the second air duct. The partition includes a first plate portion, a second plate portion, and a third plate portion. The first plate portion is located on the back side of the air supply unit and is connected to the back side of the air supply unit. The second plate portion is located above the air supply unit and is connected to the top of the cabinet body. The communication port is provided on the second plate portion. The third plate portion connects the first plate portion and the second plate portion.

[0013] In the optional technical solutions of the above-mentioned biosafety cabinet, the air outlet is connected to an indoor exhaust pipe and an outdoor exhaust pipe respectively; the working mode of the biosafety cabinet includes a first mode and a second mode; when the biosafety cabinet is in the first mode, the first control valve is configured to be open, the indoor exhaust pipe is configured to be open, and the outdoor exhaust pipe is configured to be closed; part of the gas drawn in by the bottom air inlet is blown to the working area through the first air duct, the second air duct, and the air outlet, and the other part of the gas drawn in by the bottom air inlet is discharged through the first air duct, the air outlet, and the indoor exhaust pipe; when the biosafety cabinet is in the second mode, the first control valve is configured to be open, the outdoor exhaust pipe is configured to be open, and the indoor exhaust pipe is configured to be closed; part of the gas drawn in by the bottom air inlet is blown to the working area through the first air duct, the second air duct, and the air outlet, and the other part of the gas drawn in by the bottom air inlet is discharged through the first air duct, the air outlet, and the outdoor exhaust pipe.

[0014] In the optional technical solution of the above-mentioned biosafety cabinet, a second control valve is installed in the outdoor exhaust duct, and the second control valve is configured to control the outdoor exhaust duct to open or close; the second control valve is configured to be closed in the first mode and open in the second mode; a third control valve is installed in the indoor exhaust duct, and the third control valve is configured to control the indoor exhaust duct to open or close; the third control valve is configured to be open in the first mode and closed in the second mode.

[0015] In the optional technical solution of the above-mentioned biosafety cabinet, an exhaust unit is installed at one end of the first air duct near the air outlet. The exhaust unit includes an exhaust fan and is configured to turn on when the biosafety cabinet is started. An external exhaust fan is installed in the outdoor exhaust duct and is configured to turn off in the first mode and turn on in the second mode. A second wind speed sensor is provided at the air outlet to detect the second wind speed blowing out of the air outlet. When the operating voltage of the exhaust unit is greater than or equal to a preset second voltage threshold, the exhaust unit is configured to determine the second wind speed. In the first mode, the third control valve is configured to open to its maximum opening; in the second mode, the second control valve is configured to open to its maximum opening. When the operating voltage of the exhaust unit is less than the second voltage threshold, the exhaust unit is configured to operate according to the second voltage. When the second voltage is greater than or equal to the second voltage threshold, in the first mode, the third control valve is configured to determine its opening angle based on the second wind speed; in the second mode, the second control valve is configured to determine its opening angle based on the second wind speed.

[0016] In the optional technical solutions of the above-mentioned biosafety cabinet, the biosafety cabinet is also equipped with an alarm device; when the operating voltage of the air supply unit is greater than or equal to the first voltage threshold, or when the air supply unit operates according to the first voltage and the first wind speed is less than the first preset wind speed, the alarm device issues a first alarm signal.

[0017] Those skilled in the art will understand that, when the operating voltage of the air supply unit of the biosafety cabinet is greater than or equal to a preset first voltage threshold, the first control valve is configured to open to its maximum opening. By adjusting the operating voltage of the air supply unit, the rotation speed of the air supply unit is adjusted, thereby adjusting the first airflow speed of the biosafety cabinet, making the adjustment of the first airflow speed rapid and quick. When the operating voltage of the air supply unit is less than the first voltage threshold, the air supply unit is configured to operate according to the first voltage. By adjusting the opening and closing angle of the first control valve, the first airflow speed of the biosafety cabinet is adjusted. This allows for flexible adjustment of the first airflow speed and avoids excessive noise caused by an excessively low operating voltage of the air supply unit. The embodiments of this application combine adjusting the air supply unit and adjusting the opening and closing angle of the first control valve to adjust the first airflow speed of the biosafety cabinet, ensuring that the first airflow speed meets the first target airflow speed and also avoiding excessive noise from the biosafety cabinet, thus meeting the noise requirements of the biosafety cabinet. Attached Figure Description

[0018] The following description, with reference to the accompanying drawings, outlines alternative embodiments of the biosafety cabinet of this application. The drawings are as follows:

[0019] Figure 1 This is a schematic diagram of the principle structure of the biosafety cabinet provided in the embodiments of this application;

[0020] Figure 2 This is a schematic diagram of the exhaust connector of the biosafety cabinet provided in the embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the gas flow direction in the first mode of the biosafety cabinet provided in this application embodiment;

[0022] Figure 4 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;

[0023] Figure 5 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;

[0024] Figure 6 This is a schematic diagram of the structure of the biosafety cabinet provided in the embodiments of this application;

[0025] Figure 7 This is an explosion diagram of the biosafety cabinet provided in the embodiments of this application;

[0026] Figure 8 This is a front view of the biosafety cabinet provided in the embodiments of this application;

[0027] Figure 9 yes Figure 8 Sectional view of AA.

[0028] 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: Exhaust unit; 112: Exhaust filter; 113: Bottom air duct; 114: Rear air duct; 120: Second air duct; 121: Air supply unit; 122: Air supply filter; 130: Outer shell; 131: Outer panel; 132: Bottom plate; 133: Top plate; 134: Front cover; 135: Glass door; 136: Drain tray; 1 40: Workbench; 150: Inner side panel; 160: Partition; 161: Connecting port; 162: First panel; 163: Second panel; 164: Third panel; 210: First control valve; 220: Fourth control valve; 230: Second control valve; 240: Third control valve; 300: Outdoor exhaust duct; 310: Outdoor exhaust fan; 400: Indoor exhaust duct; 500: Exhaust connector; 501: First interface; 502: Second interface; 503: Third interface; 510: Exhaust hood; 520: Pipe body; 600: Support leg. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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 before being blown back into the work area, such as the A2 type; while in others, clean air is exhausted to the outside after passing through the work area, such as the B2 type.

[0034] For A2 type biosafety cabinets, an internal air supply fan is installed to deliver air downwards into the working area, and the downward airflow speed is controlled by adjusting the fan speed. For AC fans, when the operating voltage is lower than the set value, the AC fan generates higher noise levels. Therefore, biosafety cabinet air supply fans are usually set with a minimum operating voltage to ensure that the fan noise meets the noise requirements of the biosafety cabinet. However, this setting can easily lead to excessively high downward airflow speeds, resulting in unstable downward airflow speeds that fail to meet the required standards.

[0035] In view of this, this application provides a biosafety cabinet with a first control valve at the connection port connecting the first air duct and the second air duct. When the operating voltage of the air supply unit is greater than or equal to a preset first voltage threshold, the air supply unit determines the operating voltage based on the first wind speed in the working area. At this time, the first control valve is configured to open to its maximum opening. When the operating voltage of the air supply unit is less than the first voltage threshold, the air supply unit is configured to operate according to the first voltage, and the first control valve is configured to determine the opening and closing angle based on the first wind speed. This configuration can ensure the stability of the first wind speed in the working area, avoid the first wind speed being too high or too low, meet the descent wind speed standard of the biosafety cabinet, and also avoid excessive noise caused by the air supply unit operating voltage being too low.

[0036] The optional technical solutions for the biosafety cabinets in the embodiments of this application are described below with reference to the accompanying drawings.

[0037] 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.

[0038] Figure 1 This is a schematic diagram of the principle structure of the biosafety cabinet provided in the embodiments of this application.

[0039] 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.

[0040] 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 on the lower front side of the working area 101 of the cabinet 100 for drawing in gas. An air outlet 103 is provided on the top of the working area 101 of the cabinet 100 for supplying gas into the working area 101; and an air outlet 105 is provided on the top of the cabinet 100 for discharging gas.

[0041] A first wind speed sensor is installed in the working area to detect the first wind speed blowing from the air outlet 103 into the working area. Since the air from the air outlet 103 blows downwards into the working area, the first wind speed is also referred to as the "descending wind speed".

[0042] 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. Thus, the gas 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 second air duct 120 is connected to the air supply outlet 103. Furthermore, a connecting port 161 is provided between the second air duct 120 and the first air duct 110, so that the second air duct 120 and the first air duct 110 are connected through the connecting port 161.

[0043] In this embodiment, a first control valve 210 is installed within the connection port 161. The first control valve 210 is configured to open or close to connect or disconnect the first air duct 110 and the second air duct 120. When the first control valve 210 is configured to open, the first air duct 110 and the second air duct 120 are connected, and air in the second air duct 120 can enter the first air duct 110 and be delivered to the working area 101 via the air outlet 103; when the first control valve 210 is configured to close, the first air duct 110 and the second air duct 120 are disconnected.

[0044] Combined again Figure 1 An air supply unit 121 is installed at one end of the second air duct 120 near the air outlet 103. The air supply unit 121 provides power for the gas to enter the working area 101 through the air outlet 103. An air supply filter 122 is installed between the air supply unit 121 and the air outlet 103 to filter the gas entering the working area 101. The air supply unit 121 is configured to be activated when the biosafety cabinet is in use. The air supply unit 121 is activated during the use of the biosafety cabinet, that is, the air supply unit 121 is activated in all modes of the biosafety cabinet.

[0045] When the operating voltage of the air supply unit 121 is greater than or equal to a preset first voltage threshold, the air supply unit 121 is configured to determine its operating voltage based on a first air velocity. At this time, the first control valve 210 is configured to open to its maximum opening. This can be understood as follows: when the operating voltage of the air supply unit 121 is greater than or equal to the preset first voltage threshold, the first control valve 210 opens to its maximum opening, and the air supply unit 121 dynamically adjusts its operating voltage according to the first air velocity, thereby adjusting the rotational speed of the air supply unit 121, and consequently adjusting the first air velocity of the biosafety cabinet to ensure that the first air velocity of the biosafety cabinet meets the standard. It should be noted that the maximum opening of the first control valve 210 is a pre-set, relatively large opening angle.

[0046] In this embodiment, the operating voltage of the air supply unit 121 is negatively correlated with the first wind speed. When the first wind speed is less than a preset first target wind speed, the air supply unit 121 increases its operating voltage, thereby increasing its rotational speed; when the first wind speed is greater than the first target wind speed, the air supply unit 121 decreases its operating voltage, thereby decreasing its rotational speed. Of course, when the first wind speed is equal to the first target wind speed, the air supply unit 121 maintains its operating voltage, thereby ensuring that the first wind speed is equal to the first target wind speed.

[0047] When the operating voltage of the air supply unit 121 is less than the first voltage threshold, further reducing the operating voltage would cause the air supply unit 121 to generate excessive noise, failing to meet the noise requirements of the biosafety cabinet. Therefore, the air supply unit 121 is configured to operate at a first voltage, which is greater than or equal to the first voltage threshold. In other words, the air supply unit 121 maintains operation at the first voltage. At this time, the first control valve 210 is configured to determine its opening angle based on the first airflow velocity. This can be understood as follows: when the operating voltage of the air supply unit 121 is less than the first voltage threshold, the air supply unit 121 maintains a constant operating voltage, and the first airflow velocity of the biosafety cabinet is controlled by adjusting the opening angle of the first control valve 210.

[0048] In this embodiment, the opening angle of the first control valve 210 is negatively correlated with the first wind speed. When the first wind speed is less than a preset first target wind speed, the opening angle of the first control valve 210 increases, thereby increasing the first wind speed; when the first wind speed is greater than the first target wind speed, the opening angle of the first control valve 210 decreases, thereby increasing the first wind speed. Of course, when the first wind speed equals the first target wind speed, the current opening angle of the first control valve 210 is maintained, thereby ensuring that the first wind speed equals the first target wind speed.

[0049] The air supply unit 121 in this embodiment includes an air supply fan and a voltage regulating element. The voltage regulating element is electrically connected to the air supply fan and can regulate the operating voltage of the air supply fan, thereby adjusting the operating voltage of the air supply unit 121. The voltage regulating element can be a silicon controlled rectifier (SCR), which controls the voltage of the air supply fan by controlling the current; the voltage regulating element can also be a transformer, etc.

[0050] During the aforementioned adjustment of the first airflow speed, the first control valve 210 opens, connecting the first air duct 110 and the second air duct 120 through the connecting port 161. Part 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 working area 101 through the air outlet 103. The remaining gas drawn in through the bottom air inlet 102 is discharged through the first air duct 110 and the air outlet 105. At this time, the biosafety cabinet is in its first 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. This mode can be used for standard microbiological experiments, etc.

[0051] Therefore, in this embodiment of the biosafety cabinet, when the operating voltage of the air supply unit 121 is greater than or equal to a preset first voltage threshold, the first control valve 210 is configured to open to its maximum opening. By adjusting the operating voltage of the air supply unit 121, the rotation speed of the air supply unit 121 is adjusted, thereby adjusting the first airflow speed of the biosafety cabinet, making the adjustment of the first airflow speed rapid and quick. When the operating voltage of the air supply unit 121 is less than the first voltage threshold, the air supply unit 121 is configured to operate according to the first voltage. By adjusting the opening angle of the first control valve 210, the first airflow speed of the biosafety cabinet is adjusted. This allows for flexible adjustment of the first airflow speed and avoids excessive noise caused by an excessively low operating voltage of the air supply unit 121. This embodiment of the application combines adjusting the air supply unit 121 and adjusting the opening angle of the first control valve 210 to adjust the first airflow speed of the biosafety cabinet, ensuring that the first airflow speed meets the first target airflow speed and avoiding excessive noise from the biosafety cabinet, thus meeting the noise requirements of the biosafety cabinet.

[0052] In some embodiments, a plurality of communication ports 161 are arranged at intervals along the length direction of the cabinet 100 (corresponding to the X-axis direction in the figure), and a first control valve 210 is provided in each communication port 161. This arrangement is beneficial to improving the uniformity of airflow along the length direction of the cabinet 100.

[0053] The working area 101 is arranged with multiple first wind speed sensors at intervals along the length of the cabinet 100, and the number of first wind speed sensors is the same as the number of first control valves 210. Each first wind speed sensor corresponds to one of the first control valves 210, so that each first control valve 210 corresponds to one first wind speed sensor.

[0054] When the operating voltage of the air supply unit 121 is less than the first voltage threshold, the first control valve 210 is configured to determine its opening angle based on the first wind speed detected by its corresponding first wind speed sensor. This can be understood as each first control valve 210 operating independently, which helps improve the uniformity of airflow.

[0055] Of course, when the operating voltage of the air supply unit 121 is greater than or equal to the first voltage threshold, all the first control valves 210 are opened to their maximum opening; the air supply unit 121 determines the operating voltage based on the average value of the first wind speed detected by multiple first wind speed sensors.

[0056] In some embodiments, two air supply units 121 are provided, and the two air supply units 121 are arranged at intervals along the length direction of the cabinet 100. This arrangement of two air supply units 121 can not only increase the power of airflow delivery, but also help to further improve the uniformity of airflow delivered downward to the working area 101.

[0057] Two connecting ports 161 are arranged at intervals along the length of the cabinet 100 (corresponding to the X-axis direction in the figure). Each connecting port 161 is equipped with a first control valve 210, and there are two first control valves 210 in total. At this time, there are two first wind speed sensors, and the two first wind speed sensors correspond to the two first control valves 210 respectively. For example, a first wind speed sensor is set on the left side of the working area 101, and a first wind speed sensor is set on the right side of the working area 101. At this time, the air supply unit 121 on the left corresponds to the first wind speed sensor and the first control valve 210 on the left side, and the air supply unit 121 on the right corresponds to the first wind speed sensor and the first control valve 210 on the right side.

[0058] When the operating voltage of the air supply unit 121 is greater than or equal to the first voltage threshold, the air supply unit 121 is configured to determine its operating voltage based on the first wind speed detected by its corresponding first wind speed sensor. This can be understood as each air supply unit 121 operating independently. This configuration improves both the uniformity of airflow and the reliability of the biosafety cabinet; if one air supply unit 121 fails, the other air supply unit 121 can still operate. At this time, both first control valves 210 are opened to their maximum opening.

[0059] Continue to refer to Figure 1A partition 160 is provided between the first air duct 110 and the second air duct 120. The partition 160 includes a first plate portion 162, a second plate portion 163, and a third plate portion 164. The first plate portion 162 is located on the back side of the air supply unit 121 and is connected to the back side of the air supply unit 121. The second plate portion 163 is located above the air supply unit 121 and is connected to the top of the cabinet 100. The second plate portion 163 is spaced from the first plate portion 162. The third plate portion 164 connects the first plate portion 162 and the second plate portion 163. A connecting opening 161 is provided on the second plate portion 163. Optionally, an installation pipe is provided on the second plate portion 163, forming the connecting opening 161.

[0060] In this embodiment, the first plate portion 162 is located on the back side of the air supply unit 121, and the second plate portion 163 is located above the air supply unit 121. Along the Y-axis, there is a gap between the first plate portion 162 and the second plate portion 163. Therefore, the third plate portion 164 is an inclined plate, which can provide installation space for the subsequent exhaust unit 111. In this embodiment, both the first plate portion 162 and the second plate portion 163 are vertical plates extending along the Z-axis, which not only improves the regularity of the first air duct 110 and the second air duct 120, but also facilitates the setting of the connecting port 161 and the installation of the first control valve 210.

[0061] Continue to refer to Figure 1 The air outlet 105 is connected to an indoor exhaust pipe 400 and an outdoor exhaust pipe 300. The indoor exhaust pipe 400 is used to lead the gas discharged from the air outlet 105 into the room, and the outdoor exhaust pipe 300 is used to lead the gas discharged from the air outlet 105 to the outside. Figure 2 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 2 The biosafety cabinet in this embodiment of the application also includes an exhaust connector 500, which provides a connection structure for the indoor exhaust pipe 400 and the outdoor exhaust pipe 300.

[0062] 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 exhaust pipe 300, and the third interface 503 is connected to the indoor exhaust pipe 400.

[0063] The exhaust connector 500 of this application embodiment includes an exhaust hood 510 and a pipe body 520. The exhaust hood 510 can be a rectangular cover with an opening at the bottom, and the bottom opening is a 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 respectively. The opening direction of the second interface 502 is vertical, which facilitates the connection of the outdoor exhaust 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.

[0064] Figure 3 This is a schematic diagram of the gas flow direction in the first mode of the biosafety cabinet provided in this application embodiment; Figure 4 This is a schematic diagram of the gas flow in the second mode of the biosafety cabinet provided in this application embodiment. In the figure, arrow a (without filling) represents clean gas; arrow b (with filling) represents contaminated gas.

[0065] Combination Figure 3 and Figure 4 The working modes of the biosafety cabinet in this application embodiment include a first mode and a second mode.

[0066] When the biosafety cabinet is in the first mode, the first control valve 210 is configured to open to connect the first air duct 110 and the second air duct 120; the indoor exhaust duct 400 is configured to open and the outdoor exhaust duct 300 is configured to close; part of the gas drawn in by the bottom air inlet 102 enters the second air duct 120 through the first air duct 110 and the connecting port 161, and the gas in the second air duct 120 is blown to the work area 101 through the air supply port 103; the other part of the gas drawn in by the bottom air inlet 102 is discharged through the first air duct 110, the air outlet 105 and the indoor exhaust duct 400.

[0067] When the biosafety cabinet is in the second mode, the first control valve 210 is configured to open to connect the first air duct 110 and the second air duct 120; the outdoor exhaust duct 300 is configured to open and the indoor exhaust duct 400 is configured to close; part of the gas drawn in by the bottom air inlet 102 enters the second air duct 120 through the first air duct 110 and the connecting port 161, and the gas in the second air duct 120 is blown to the work area 101 through the air supply port 103; the other part of the gas drawn in by the bottom air inlet 102 is discharged through the first air duct 110, the air outlet 105 and the outdoor exhaust duct 300.

[0068] The difference between the first and second modes is that in the first mode, the gas in the outlet 105 is exhausted into the room through the indoor exhaust duct 400, and the first mode can be applied to standard microbiological experiments, etc.; in the second mode, the gas in the outlet 105 is exhausted to the outside through the outdoor exhaust duct 300. The second mode can be applied to microbiological experiments where trace amounts of volatile toxic chemicals and trace amounts of radioactive elements are used as auxiliary agents. Compared to the third mode described later, the second mode has lower power consumption and is more energy-efficient. Therefore, the biosafety cabinet of this application embodiment can be of different types to suit different experimental requirements, thus improving 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.

[0069] In order to achieve on / off control of the outdoor exhaust duct 300, combined with Figure 3 and Figure 4 In this embodiment of the application, a second control valve 230 is installed inside the outdoor exhaust duct 300. The second control valve 230 is configured to control the opening or closing of the outdoor exhaust duct 300. When the second control valve 230 is open, the outdoor exhaust duct 300 is open; when the second control valve 230 is closed, the outdoor exhaust duct 300 is closed. The second control valve 230 is configured to be closed in a first mode and open under A2 exhaust.

[0070] In order to achieve on / off control of the indoor exhaust duct 400, combined with Figure 3 and Figure 4 A third control valve 240 is installed inside the indoor exhaust duct 400. The third control valve 240 is configured to control the opening or closing of the indoor exhaust duct 400. When the third control valve 240 is configured to be open, the indoor exhaust duct 400 is configured to be open; when the third control valve 240 is configured to be closed, the indoor exhaust duct 400 is configured to be closed. The third control valve 240 is configured to be open in a first mode and closed in a second mode.

[0071] Continue to refer to Figure 1 , Figure 3 and Figure 4 To power the exhaust of air from the vent 105, an exhaust unit 111 is installed at one end of the first air duct 110 near the vent 105, thereby providing power for gas exhaust, particularly when exhausting into the indoor exhaust duct 400. An exhaust filter 112 is installed between the exhaust unit 111 and the vent 105 to filter the exhaust gas. The exhaust unit 111 is configured to be activated when the biosafety cabinet is in use; that is, the exhaust unit 111 is activated in all modes of the biosafety cabinet.

[0072] Optionally, when the biosafety cabinet is operating in the subsequent third and second modes, the exhaust unit 111 does not need to be activated, and only the external exhaust fan 310 provides exhaust power. In the first mode, the exhaust unit 111 must be activated to prevent indoor air from flowing back into the biosafety cabinet through the air outlet 105.

[0073] To provide power for gas exhaust, an exhaust fan 310 is installed inside the outdoor exhaust duct 300. In the second mode, when the second control valve 230 is configured to open, the exhaust fan 310 is configured to start to improve exhaust efficiency and prevent outdoor air backflow into the biosafety cabinet. In the first mode, the exhaust fan 310 is configured to be off.

[0074] In this embodiment of the application, a second wind speed sensor is provided at the air outlet 105. The second wind speed sensor is used to detect the second wind speed blown out of the air outlet 105.

[0075] When the operating voltage of the exhaust unit 111 is greater than or equal to a preset second voltage threshold, the exhaust unit 111 is configured to determine its operating voltage based on the second wind speed. In the first mode, the third control valve 240 is configured to open to its maximum opening; in the second mode, the second control valve 230 is configured to open to its maximum opening. This can be understood as follows: when the operating voltage of the exhaust unit 111 is greater than or equal to the second voltage threshold, either the second control valve 230 or the third control valve 240 opens to its maximum opening, adjusting the second wind speed by regulating the operating voltage of the exhaust unit 111, thus enabling rapid and quick adjustment of the second wind speed.

[0076] In this embodiment, the operating voltage of the exhaust unit 111 is negatively correlated with the second wind speed. When the second wind speed is less than the preset second target wind speed, the exhaust unit 111 increases its operating voltage, thereby increasing its rotational speed; when the second wind speed is greater than the second target wind speed, the exhaust unit 111 decreases its operating voltage, thereby decreasing its rotational speed. Of course, when the second wind speed is equal to the second target wind speed, the exhaust unit 111 maintains its operating voltage, thereby ensuring that the second wind speed is equal to the second target wind speed.

[0077] When the operating voltage of the exhaust unit 111 is less than the second voltage threshold, the exhaust unit 111 is configured to operate according to the second voltage. When the second voltage is greater than or equal to the second voltage threshold, in the first mode, the third control valve 240 is configured to determine its opening angle based on the second airflow rate. In the second mode, the second control valve 230 is configured to determine its opening angle based on the second airflow rate. This can be understood as follows: when the operating voltage of the exhaust unit 111 is less than the second voltage threshold, the exhaust unit 111 maintains a constant operating voltage. By adjusting the opening angle of the second control valve 230 or the third control valve 240, the second airflow rate of the biosafety cabinet is controlled. This allows for flexible adjustment of the second airflow rate and avoids excessive noise caused by excessively low operating voltage of the exhaust unit 111.

[0078] The exhaust unit 111 of this embodiment includes a supply fan and a voltage regulating element. The voltage regulating element is electrically connected to the supply fan and can regulate the operating voltage of the exhaust fan, thereby adjusting the operating voltage of the exhaust unit 111. The voltage regulating element can be a silicon controlled rectifier (SCR), which controls the voltage of the supply fan by controlling the current; the voltage regulating element can also be a transformer, etc.

[0079] In this embodiment, the opening angles of the second control valve 230 and the third control valve 240 are negatively correlated with the second wind speed. When the second wind speed is less than the preset second target wind speed, the opening angle of the second control valve 230 or the third control valve 240 increases, thereby increasing the second wind speed; when the second wind speed is greater than the second target wind speed, the opening angle of the second control valve 230 or the third control valve 240 decreases, thereby increasing the second wind speed. Of course, when the second wind speed is equal to the second target wind speed, the current opening angle of the second control valve 230 or the third control valve 240 is maintained, thereby ensuring that the second wind speed is equal to the second target wind speed.

[0080] Therefore, the biosafety cabinet in this embodiment of the application adopts a combination of adjusting the exhaust unit 111 and adjusting the opening and closing angle of the control valve to adjust the second wind speed of the biosafety cabinet, ensuring the ratio between the second wind speed and the first wind speed, thereby ensuring the air volume distribution ratio of the biosafety cabinet, and also avoiding excessive noise from the biosafety cabinet, thus meeting the noise requirements of the biosafety cabinet.

[0081] The biosafety cabinet in this embodiment is also equipped with an alarm device; when the operating voltage of the air supply unit 121 is greater than or equal to a first voltage threshold, or when the air supply unit 121 operates at the first voltage and the first wind speed is less than a first preset wind speed, the alarm device issues a first alarm signal. The first preset wind speed is much less than the first target wind speed.

[0082] This can be understood as follows: when the air supply unit 121 is operating normally, if the first air velocity is too low, it indicates that the first control valve 210 is malfunctioning, and the alarm device will issue a first alarm signal. The alarm device can be a display, indicator light, or speaker light, and the first alarm signal can be displayed on the display as a warning sign, or as an audible signal or visual signal.

[0083] The biosafety cabinet in this application embodiment also includes a third mode, thereby expanding the application range of the biosafety cabinet. The following is in conjunction with... Figure 5 To explain, among other things, Figure 5 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.

[0084] A top air inlet 104 is provided on the top of the cabinet 100. A fourth control valve 220 is installed at the top air inlet 104. The fourth control valve 220 is configured to control the opening or closing of the top air inlet 104. When the fourth control valve 220 is open, the top air inlet 104 is open, and indoor air can enter the second air duct 120 through the top air inlet 104. When the fourth control valve 220 is closed, the top air inlet 104 is closed.

[0085] It should be noted that, in the embodiments of this application, the first control valve 210, the fourth control valve 220, the second control valve 230 and the third control valve 240 are to be interpreted in a broad sense. They can be 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.

[0086] In the third mode, the first control valve 210 is configured to close to isolate the first air duct 110 and the second air duct 120, and the fourth control valve 220 is configured to open the top air inlet 104, the second control valve 230 is configured to open the outdoor exhaust duct 300, and the third control valve 240 is configured to close the indoor exhaust duct 400. The exhaust unit 111 and the external exhaust fan 310 are configured to open, so that the gas drawn in through the bottom air inlet 102 is discharged through the first air duct 110, the air outlet 105, and the outdoor exhaust duct 300; the air supply unit 121 is configured to start, and the gas drawn in through the top air inlet 104 is blown to the work area 101 through the second air duct 120 and the air supply outlet 103. The biosafety cabinet in the third mode can be used in microbial experiments where volatile toxic chemicals and radioactive elements are used as auxiliary agents.

[0087] Therefore, in this embodiment, the biosafety cabinet can operate in three modes, and the on / off states of the control valves and motors are detailed in Table 1:

[0088] Table 1

[0089] model Valve 1 Valve 2 Valve Three Valve 4 air supply unit Exhaust unit External exhaust fan First Mode open close open close run run closure Second Mode open open close close run run run Third Mode close open close open run run run

[0090] It should be noted that the first mode is the operating mode of the A2 type biosafety cabinet, the second mode is the operating mode of the A2 exhaust type biosafety cabinet, and the third mode is the operating mode of the B2 type. In the table above, "Valve 1" represents the first control valve, "Valve 2" represents the second control valve, "Valve 3" represents the third control valve, and "Valve 4" represents the fourth control valve.

[0091] Therefore, the biosafety cabinet in this embodiment controls the direction of gas flow in the air duct by controlling four electrically controlled valves and three fans, so that the biosafety cabinet can be formed in different types to suit different experimental requirements, thereby improving 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.

[0092] There are several ways to create the aforementioned air ducts and vents within the cabinet 100, as shown below. Figures 6 to 9 This describes the structure of the cabinet in the embodiments of this application. Figure 6 This is a schematic diagram of the structure of the biosafety cabinet provided in the embodiments of this application; Figure 7 This is an explosion diagram of the biosafety cabinet provided in the embodiments of this application; Figure 8 This is a front view of the biosafety cabinet provided in the embodiments of this application; Figure 9 yes Figure 8 Sectional view of AA.

[0093] First, combine again Figure 1 In some possible implementations, the first air duct 110 includes a connected bottom air duct 113 and a rear air duct 114. 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, facilitating 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 within the cabinet 100 have a compact structure.

[0094] Combination Figure 6 , Figure 7 , Figure 8 as well as Figure 9 The cabinet 100 in this embodiment includes: an outer shell 130, a workbench 140, and an inner side panel 150.

[0095] 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. A glass door 135 is provided below the front cover 134. The glass door 135 can slide along the length of both sides of the outer side panel 131 to open or close the front window. The top air inlet 104 and the air outlet 105 are both provided on the top plate 133 to facilitate the intake and exhaust of air. The bottom air inlet 102 is provided on the bottom plate 132, for example, the bottom air inlet 102 is provided on the front side of the bottom plate 132.

[0096] 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.

[0097] 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.

[0098] A partition 160 is fixed between the inner side panel 150 and the top panel 133. The first portion 162 of the partition 160 is connected to the inner side panel 150, and the second portion 163 of the partition 160 is fixedly connected to the top panel 133. 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 filter.

[0099] 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.

[0100] 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.

[0101] In summary, the biosafety cabinet of this embodiment is provided with a first control valve 210 at the connection port 161 of the first air duct 110 and the second air duct 120. When the operating voltage of the air supply unit 121 is greater than or equal to a preset first voltage threshold, the first control valve 210 is configured to open to its maximum opening. By adjusting the operating voltage of the air supply unit 121, the rotation speed of the air supply unit 121 is adjusted, thereby adjusting the first air speed of the biosafety cabinet, making the adjustment of the first air speed quick and easy. When the operating voltage of the air supply unit 121 is less than the first voltage threshold, the air supply unit 121 is configured to operate according to the first voltage. By adjusting the opening angle of the first control valve 210, the first air speed of the biosafety cabinet is adjusted. This not only allows for flexible adjustment of the first air speed but also avoids excessive noise caused by the operating voltage of the air supply unit 121 being too low. This embodiment of the application combines two methods: adjusting the air supply unit 121 and adjusting the opening angle of the first control valve 210, to adjust the first air velocity of the biosafety cabinet, ensuring that the first air velocity meets the first target air velocity, and also avoiding excessive noise from the biosafety cabinet, thus meeting the noise requirements of the biosafety cabinet.

[0102] 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 biosafety cabinet, characterized in that, include: Cabinet; The cabinet encloses a working area with an opening on the front. The cabinet has a bottom air inlet at the lower front of the working area and an air outlet at the top of the working area. An air outlet is also provided at the top of the cabinet. A first wind speed sensor is installed within the working area to detect the first wind speed blowing from the air outlet into the working area. The cabinet body forms 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 second air duct is connected to the air supply outlet. A connection port is provided between the second air duct and the first air duct. A first control valve is provided in the connection port. The first control valve is configured to open or close the connection port so that the first air duct and the second air duct are connected or disconnected. An air supply unit is installed at one end of the second air duct near the air outlet. The air supply unit includes an air supply fan. The air supply unit is configured to determine the operating voltage of the air supply unit according to the first wind speed when the operating voltage of the air supply unit is greater than or equal to a preset first voltage threshold. The first control valve is configured to open to the maximum opening. When the operating voltage of the air supply unit is less than the first voltage threshold, the air supply unit is configured to operate according to the first voltage, and the first control valve is configured to determine the opening and closing angle of the first control valve according to the first wind speed, wherein the first voltage is greater than or equal to the first voltage threshold. Two communication ports are arranged at intervals along the length of the cabinet, and each communication port is provided with the first control valve. The first control valve is configured to determine the opening and closing angle of the first control valve based on the first wind speed detected by the corresponding first wind speed sensor when the operating voltage of the air supply unit is less than the first voltage threshold. When the first wind speed is less than the preset first target wind speed, the opening angle of the first control valve increases; When the first wind speed is greater than the first target wind speed, the opening angle of the first control valve decreases; When the first wind speed is equal to the first target wind speed, maintain the current opening and closing angle of the first control valve; Two air supply units are provided, and the two air supply units are arranged at intervals along the length of the cabinet. There are two first wind speed sensors, and the two first wind speed sensors correspond to the two first control valves respectively, and the two first wind speed sensors correspond to the two air supply units respectively. The air supply unit is configured to determine the operating voltage of the air supply unit based on the first wind speed detected by the corresponding first wind speed sensor when the operating voltage of the air supply unit is greater than or equal to the first voltage threshold. A partition is provided between the first air duct and the second air duct, and the partition includes a first plate portion, a second plate portion and a third plate portion; The first plate is located on the back side of the air supply unit, and the first plate is connected to the back side of the air supply unit. The second plate is located above the air supply unit and is connected to the top of the cabinet; the communication port is provided on the second plate. The third plate portion connects the first plate portion and the second plate portion.

2. The biosafety cabinet according to claim 1, characterized in that, When the first wind speed is less than the preset first target wind speed, the operating voltage of the air supply unit increases; When the first wind speed is greater than the first target wind speed, the operating voltage of the air supply unit decreases.

3. The biosafety cabinet according to claim 1, characterized in that, The air outlets are respectively connected to indoor exhaust pipes and outdoor exhaust pipes; The biosafety cabinet has two operating modes: a first mode and a second mode. When the biosafety cabinet is in the first mode, the first control valve is configured to open, the indoor exhaust duct is configured to open, and the outdoor exhaust duct is configured to close; a portion of the gas drawn in by the bottom air inlet is blown to the work area via the first air duct, the second air duct, and the air outlet, and the remaining portion of the gas drawn in by the bottom air inlet is discharged via the first air duct, the air outlet, and the indoor exhaust duct. When the biosafety cabinet is in the second mode, the first control valve is configured to open, the outdoor exhaust duct is configured to open, and the indoor exhaust duct is configured to close; a portion of the gas drawn in through the bottom air inlet is blown to the work area via the first air duct, the second air duct, and the air outlet, and the remaining portion of the gas drawn in through the bottom air inlet is discharged via the first air duct, the air outlet, and the outdoor exhaust duct.

4. The biosafety cabinet according to claim 3, characterized in that, A second control valve is installed inside the outdoor exhaust duct. The second control valve is configured to control the outdoor exhaust duct to open or close. The second control valve is configured to close in the first mode and open in the second mode. A third control valve is installed inside the indoor exhaust duct, and the third control valve is configured to control the opening or closing of the indoor exhaust duct; the third control valve is configured to open in the first mode and close in the second mode.

5. The biosafety cabinet according to claim 4, characterized in that, An exhaust unit is installed at one end of the first air duct near the air outlet. The exhaust unit includes an exhaust fan and is configured to turn on when the biosafety cabinet is started. An external exhaust fan is installed in the outdoor exhaust duct, and the external exhaust fan is configured to be turned off in the first mode and turned on in the second mode. The air outlet is equipped with a second wind speed sensor, which is used to detect the second wind speed blowing out of the air outlet. When the operating voltage of the exhaust unit is greater than or equal to a preset second voltage threshold, the exhaust unit is configured to determine the operating voltage of the exhaust unit according to the second wind speed. In the first mode, the third control valve is configured to open to the maximum opening. In the second mode, the second control valve is configured to open to its maximum opening; When the operating voltage of the exhaust unit is less than the second voltage threshold, the exhaust unit is configured to operate according to the second voltage. The second voltage is greater than or equal to the second voltage threshold. In the first mode, the third control valve is configured to determine the opening and closing angle of the third control valve according to the second wind speed. In the second mode, the second control valve is configured to determine the opening and closing angle of the second control valve according to the second wind speed.

6. The biosafety cabinet according to claim 1, characterized in that, The biosafety cabinet is also equipped with an alarm device; When the operating voltage of the air supply unit is greater than or equal to the first voltage threshold, or when the air supply unit operates at the first voltage and the first wind speed is less than the first preset wind speed, the alarm device issues a first alarm signal.

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