Fume hood and fire extinguishing method

Abstract

The application discloses a fume exhaust cabinet, which comprises a cabinet body, an inner cavity, a work cavity, a window, a fume exhaust system, a fire extinguishing sensor, a fire extinguishing device and a nozzle. The window is arranged on the front wall of the cabinet body and can move upwards or downwards along the height direction of the cabinet body. The fume exhaust system is used for exhausting air entering the work cavity. The fire extinguishing sensor is arranged on the cavity wall of the work cavity. The fire extinguishing device is arranged outside the work cavity and used for storing fire extinguishing agent. The nozzle is arranged on the cavity wall of the work cavity and connected with the fire extinguishing device. When the fire extinguishing sensor detects a fire source in the work cavity, the nozzle sprays the fire extinguishing agent into the work cavity, the window moves downwards along the height direction of the cabinet body to be closed, the fume exhaust system is in an open state, and the work cavity is in a negative pressure state. The application can realize fire extinguishing under negative pressure. The application also provides a fire extinguishing method.

Description

Technical Field

[0001] The present invention relates to the technical field of fume hoods, and in particular to a fume hood and a fire extinguishing method. Background Art

[0002] Ventilation equipment can generally be described as equipment that removes waste gas, harmful gas, particulate matter and other gases in a work space to the outside of the work space (usually outdoors). This type of equipment is widely used in industry and life. For example, factories that produce toxic, harmful or particulate gases in industrial production, biological and chemical laboratories in research and development institutions, kitchens that produce fumes when cooking, etc., all require ventilation equipment to isolate the toxic gases and particulate matter in a certain work space from the users, prevent the users from inhaling toxic and harmful gases and particulate matter, and discharge the toxic and harmful gases and particulate matter to the outdoors.

[0003] Fume hoods are essential equipment for controlling contaminants in laboratories. Their function is to control pollutants emitted from within the hood and exhaust them outdoors, preventing them from escaping through the hood's operating ports and potentially endangering the health and safety of laboratory personnel. In some cases, a fire can occur within the hood during use, creating a fire source that can compromise the safety of laboratory personnel and equipment.

[0004] Therefore, it is necessary to be able to extinguish the fire in time after the exhaust cabinet catches fire. Summary of the Invention

[0005] The present invention aims to solve the technical problem of fume hood fires. The present invention provides an exhaust hood and a fire extinguishing method, which can achieve "negative pressure fire extinguishing" after the exhaust hood fire occurs, with minimal impact on the laboratory environment and experiments inside the hood.

[0006] In order to solve the above technical problems, an embodiment of the present invention discloses an exhaust cabinet, comprising: a cabinet body, having an inner cavity, which constitutes a working cavity; a window, which is arranged on the front wall of the cabinet body, and the window can move upward or downward along the height direction of the cabinet body; an exhaust system, which is used to discharge the air entering the working cavity from the working cavity; a fire extinguishing sensor, which is arranged on the cavity wall of the working cavity; a fire extinguishing device, which is used to store fire extinguishing agent and is arranged outside the working cavity; a nozzle, which is arranged on the cavity wall of the working cavity, and the nozzle is connected to the fire extinguishing device; wherein, the nozzle can spray fire extinguishing agent into the working cavity when the fire extinguishing sensor detects a fire source in the working cavity, and the window moves downward along the height direction of the cabinet body to close, and the exhaust system is in an open state, so that the working cavity is in a negative pressure state.

[0007] By adopting the above technical solution, the purpose of "fire extinguishing under negative pressure, effective fire extinguishing inside the cabinet, and safety outside the cabinet" can be achieved.

[0008] According to another specific embodiment of the present invention, the fire extinguishing agent is perfluorohexanone.

[0009] According to another specific embodiment of the present invention, it further includes: an air supply system, which is used to supply air to the working chamber. When the fire extinguishing sensor detects a fire source in the working chamber, the air supply system is in a closed state.

[0010] According to another specific embodiment of the present invention, the nozzle is provided on the top wall of the working chamber.

[0011] According to another specific embodiment of the present invention, the internal width of the fume hood is W, the internal depth of the fume hood is D, and the internal height of the fume hood is H;

[0012] Along the width direction of the fume hood, the width of the nozzle from the center line of the fume hood is W1, where 0mm≤W1≤0.32W;

[0013] Along the depth direction of the fume hood, the depth of the nozzle from the rear cavity wall of the fume hood is D1, wherein 0.3D≤D1≤0.5D;

[0014] Along the height direction of the fume hood, the height between the nozzle and the top cavity wall of the fume hood is H1, wherein 0mm

[0015] According to another specific embodiment of the present invention, 0mm<W≤1200mm, the number of the nozzles is one, W1=0mm; or, 1200mm<W≤1800mm, the number of the nozzles is two, and the width of each of the nozzles from the center line of the fume hood is W1, wherein 0.17W≤W1≤0.25W; or, 1800mm<W≤2400mm, the number of the nozzles is three, one of the nozzles is located at the center line of the fume hood, and the width of each of the remaining nozzles from the center line of the fume hood is W1, wherein 0.25W≤W1≤0.32W.

[0016] According to another embodiment of the present invention, Q min ≤Q 排 ≤N*V, where Q 排 It represents the fire extinguishing exhaust volume of the exhaust system when the nozzle sprays the fire extinguishing agent, Q min represents the minimum exhaust volume of the exhaust system while ensuring the minimum air change rate, N represents the air change rate of the fume hood, V represents the volume of the working chamber of the fume hood, and the minimum air change rate of the fume hood is 150 times / hour. In some possible embodiments, N=200.

[0017] ​According to another specific embodiment of the present invention, the capacity of the fire extinguishing agent stored in the fire extinguishing device is G, G=(V / S)×C1×K; wherein V represents the volume of the working chamber of the exhaust cabinet, S represents the specific volume of the fire extinguishing agent, C1 represents the fire extinguishing design concentration or the inerting design concentration, and K represents the pressure correction coefficient of the room where the exhaust cabinet is located.

[0018] According to another specific embodiment of the present invention, the pressure of the room is 0Pa, K=1; the pressure of the room is -2Pa, K=1.03; the pressure of the room is -5Pa, K=1.063; the pressure of the room is -8Pa, K=1.08.

[0019] According to another specific embodiment of the present invention, the fire extinguishing sensor is arranged on the top cavity wall of the working cavity and is arranged facing the bottom cavity wall of the working cavity.

[0020] According to another specific embodiment of the present invention, the fire extinguishing sensor includes any one or more of the following: a photoelectric smoke detector, a flame detector, and a temperature detector.

[0021] According to another specific embodiment of the present invention, the fume hood includes a controller, and the controller is connected to the window, the air supply system, the exhaust system, the fire extinguishing sensor, the nozzle, and the fire extinguishing device.

[0022] The present application also provides a fume hood fire extinguishing method, comprising:

[0023] A fire source is detected in the working chamber of the fume hood;

[0024] Controlling the window of the fume hood to move downward along the height direction of the fume hood body and close;

[0025] Control the exhaust system of the fume hood to be in the open state so that the working chamber of the fume hood is in a negative pressure state;

[0026] The nozzle in the working chamber of the fume hood is controlled to spray the fire extinguishing agent into the working chamber of the fume hood.

[0027] According to another specific embodiment of the present invention, the fire extinguishing agent is perfluorohexanone.

[0028] According to another specific embodiment of the present invention, the fire extinguishing method further includes: controlling the air supply system of the fume hood to be in a closed state, so that the working chamber of the fume hood is in a negative pressure state.

[0029] According to another specific embodiment of the present invention, a fire extinguishing sensor detects a fire source in the working chamber of the fume hood and controls the sound and light alarm to send out an alarm signal.

[0030] According to another specific embodiment of the present invention, at least two fire extinguishing sensors detect a fire source in the working chamber of the fume hood and control the nozzle to spray the fire extinguishing agent into the working chamber of the fume hood.

[0031] According to another specific embodiment of the present invention, the air supply system of the fume hood is controlled to be in a closed state for 60 seconds, and the exhaust system of the fume hood is controlled to be in an open state for 60 seconds.

[0032] According to another specific embodiment of the present invention, the nozzle is controlled to spray the fire extinguishing agent in the fire extinguishing device within 10 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Shows a three-dimensional diagram of the exhaust cabinet according to an embodiment of the present invention Figure 1 ;

[0034] Figure 2 The main view of the exhaust cabinet according to the embodiment of the present invention is shown. Figure 1 ;

[0035] Figure 3 A side view of a fume hood according to an embodiment of the present invention is shown. Figure 1 ;

[0036] Figure 4 A perspective view showing a fire extinguishing sensor in a fume hood according to an embodiment of the present invention;

[0037] Figure 5 Shows a three-dimensional diagram of the exhaust cabinet according to an embodiment of the present invention Figure 2 ;

[0038] Figure 6 Shows a top view of the fume hood according to an embodiment of the present invention Figure 1 ;

[0039] Figure 7 The main view of the exhaust cabinet according to the embodiment of the present invention is shown. Figure 2 ;

[0040] Figure 8 A side view of a fume hood according to an embodiment of the present invention is shown. Figure 2 ;

[0041] Figure 9 Shows a top view of the fume hood according to an embodiment of the present invention Figure 2 ;

[0042] Figure 10 Shows a top view of the fume hood according to an embodiment of the present invention Figure 3 ;

[0043] Figure 11 Shows a top view of the fume hood according to an embodiment of the present invention Figure 4 ;

[0044] Figure 12Shows a three-dimensional diagram of the exhaust cabinet according to an embodiment of the present invention Figure 3 ;

[0045] Figure 13 Shows a top view of the fume hood according to an embodiment of the present invention Figure 5 ;

[0046] Figure 14 The main view of the exhaust cabinet according to the embodiment of the present invention is shown. Figure 3 ;

[0047] Figure 15 A side view of a fume hood according to an embodiment of the present invention is shown. Figure 3 ;

[0048] Figure 16 The concentration curve of the external measuring point P1 of the fume hood according to the embodiment of the present invention is shown;

[0049] Figure 17 The concentration curve of the external measuring point P2 of the fume hood according to the embodiment of the present invention is shown;

[0050] Figure 18 The concentration curve of the external measuring point P3 of the fume hood according to the embodiment of the present invention is shown;

[0051] Figure 19 A concentration curve diagram of measuring point A1 inside the fume hood according to an embodiment of the present invention is shown;

[0052] Figure 20 A concentration curve diagram of measuring point A2 inside the fume hood according to an embodiment of the present invention is shown;

[0053] Figure 21 A concentration curve diagram of measuring point A3 inside the fume hood according to an embodiment of the present invention is shown;

[0054] Figure 22 A concentration curve diagram of measuring point A4 inside the fume hood according to an embodiment of the present invention is shown;

[0055] Figure 23 The concentration curve of the measuring point A5 inside the fume hood according to the embodiment of the present invention is shown;

[0056] Figure 24 A concentration curve diagram of measuring point A6 inside the fume hood according to an embodiment of the present invention is shown;

[0057] Figure 25 The concentration curve of the measuring point A7 inside the fume hood according to the embodiment of the present invention is shown;

[0058] Figure 26 A concentration curve diagram of measuring point A8 inside the fume hood according to an embodiment of the present invention is shown;

[0059] Figure 27 A concentration curve diagram of measuring point A9 inside the fume hood according to an embodiment of the present invention is shown;

[0060] Figure 28 A concentration curve diagram of the measuring point B1 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0061] Figure 29 A concentration curve diagram of the measuring point B2 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0062] Figure 30 A concentration curve diagram of the measuring point B3 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0063] Figure 31 A concentration curve diagram of the measuring point B4 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0064] Figure 32 A concentration curve diagram of the measuring point B5 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0065] Figure 33 A concentration curve diagram of the measuring point B6 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0066] Figure 34 A concentration curve diagram of the measuring point B7 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0067] Figure 35 A concentration curve diagram of the measuring point B8 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0068] Figure 36 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0069] Figure 37 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0070] Figure 38 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0071] Figure 39 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0072] Figure 40 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0073] Figure 41 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0074] Figure 42 A concentration curve diagram of the measuring point B9 inside the fume exhaust cabinet according to the embodiment of the application is shown;

[0075] Figure 43 Fig. 7 shows the isosurface of the 7th second when the concentration of the fire extinguishing agent in the fume hood according to the embodiment of the present application is 5.9%;

[0076] Figure 44 Fig. 8 shows the isosurface of the 8th second when the concentration of the fire extinguishing agent in the fume hood according to the embodiment of the present application is 5.9%;

[0077] Figure 45 Fig. 9 shows the isosurface of the 9th second when the concentration of the fire extinguishing agent in the fume hood according to the embodiment of the present application is 5.9%;

[0078] Figure 46 Fig. 10 shows the isosurface of the 10th second when the concentration of the fire extinguishing agent in the fume hood according to the embodiment of the present application is 5.9%. DETAILED DESCRIPTION

[0079] The present application is described in detail by specific embodiments, and other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure of the present application. Although the description of the present application will be introduced in combination with the preferred embodiments, this does not mean that the features of the present application are limited to the embodiments. On the contrary, the purpose of introducing the present application in combination with the embodiments is to cover other options or modifications that can be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0080] It should be noted that in the present specification, similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0081] In the description of the present embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0082] The terms "first", "second", and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0083] In the description of this embodiment, it should be noted that, unless otherwise specified or limited, the terms "disposed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this embodiment based on specific circumstances.

[0084] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0085] In some possible implementations, a fire detection tube is arranged inside the fume hood. When a fire occurs inside the fume hood, the 170-degree flame burns through the fire detection tube, and the fire extinguishing agent sprays out from the rupture, thereby extinguishing the fire. Alternatively, in some possible implementations, the flame burns through the fire detection tube, causing the pressure inside the fire detection tube to drop. The pressure drop signal triggers the bottle mouth solenoid valve of the fire extinguishing device to open, and the fire extinguishing agent sprays out from the metal pipe nozzle, thereby extinguishing the fire. However, this fire extinguishing method cannot extinguish early-stage fires in a timely manner. After the fire extinguishing agent in the fire extinguishing device is sprayed, the pressure inside the fume hood increases, and toxic and harmful gases in the cabinet will leak into the laboratory space.

[0086] To this end, this application provides another fire extinguishing method: fire extinguishing under negative pressure, which has less impact on the laboratory environment inside the cabinet and the experiments inside the cabinet.

[0087] For example, refer to Figures 1 to 14 The present application provides a fume hood 1, comprising a cabinet body 10. The cabinet body 10 has a front wall 101, a rear cavity wall 103, a left wall 105, a right wall 106, a top cavity wall 104 and a bottom cavity wall 102. The front wall 101 and the rear cavity wall 103 are arranged along the depth direction of the fume hood 1 ( Figure 3 The left wall 105 and the right wall 106 are arranged relative to each other along the width direction of the exhaust cabinet 1 ( Figure 2 The top cavity wall 104 and the bottom cavity wall 102 are arranged relative to each other along the height direction of the exhaust cabinet 1 ( Figures 1 to 3 、 Figure 8 、 Figure 12 The above cavity walls enclose the inner cavity of the cabinet body 10, and the inner cavity constitutes the working cavity 11 of the exhaust cabinet 1.

[0088] Among them, when the exhaust cabinet 1 is placed in an indoor environment, the wall of the cabinet 10 that the user faces during operation is the front wall 101. A window 20 is provided on the front wall 101 of the cabinet 10. The window 20 can be opened along the height direction of the cabinet 10 ( Figures 1 to 3 、 Figure 8 、Figure 12 Alternatively, the viewing window 20 moves downward along the height direction of the cabinet body 10 to open to form a front opening open to the indoor environment, and the front opening serves as an operation port.

[0089] The fume hood 1 of the present application also includes an air supply system and an exhaust system. The air supply system is used to supply air to the working chamber 11, and the exhaust system is used to exhaust the air entering the working chamber 11 from the working chamber 11. Exemplarily, the air supply system includes an air supply valve and an air supply port provided on the fume hood 1. The exhaust system includes an exhaust valve and an exhaust port 12 provided on the fume hood 1. Exemplarily, the exhaust port 12 on the fume hood 1 is provided at the top of the fume hood 1. In some possible embodiments, the fume hood 1 does not include an air supply system.

[0090] A fire extinguishing sensor and a nozzle 50 are provided on the cavity wall of the working chamber 11 of the cabinet 10. For example, the fire extinguishing sensor and the nozzle 50 are provided on the top cavity wall 104 of the working chamber 11. A fire extinguishing device 40 is provided outside the working chamber 11 of the cabinet 10. For example, the fire extinguishing device 40 is provided on the top of the cabinet 10. The fire extinguishing device 40 is used to store fire extinguishing agent and is connected to the nozzle 50. For example, the fire extinguishing device 40 is connected to the nozzle 50 via a fire extinguishing agent pipeline 43 to supply fire extinguishing agent to the nozzle 50. There is no limit on the number of nozzles 50 and it can be set accordingly according to the needs of fire extinguishing. For example, the number of nozzles 50 can be one, two, three, etc.

[0091] For example, the fire extinguishing sensor includes any one or more of the following: photoelectric smoke detector 30, flame detector 32 (infrared flame detector and ultraviolet flame detector), temperature detector 31. Figures 2 to 4 As shown, the fire extinguishing sensor in the present application includes: a photoelectric smoke detector 30, a flame detector 32, and a temperature detector 31. The photoelectric smoke detector 30, the flame detector 32, and the temperature detector 31 are arranged on the fire extinguishing mounting plate and connected to the cavity wall (for example, the top cavity wall 104) of the working chamber 11 through the fire extinguishing mounting plate. There is no limitation on the connection method between the fire extinguishing mounting plate and the cavity wall of the working chamber 11. For example, in the present application, a screw hole 331 is provided on the fire extinguishing mounting plate, and the screw hole 331 of the fire extinguishing mounting plate is fixedly connected to the cavity wall of the working chamber 11 by screws (not shown).

[0092] In the present application, the nozzle 50 can spray the extinguishing agent to the working chamber 11 when the fire sensor detects the fire source in the working chamber 11, and the window 20 moves downward along the height direction of the cabinet 10 to close, the air supply system is in the closed state, and the exhaust system is in the open state, so that the working chamber 11 is in a negative pressure state. That is, when the fire sensor detects the fire source in the working chamber 11, it means that the working chamber 11 of the exhaust cabinet 1 is on fire, the window 20 will move downward to close (cut off oxygen supply, prevent pollutants, and overflow of extinguishing agent), and the air supply system is in the closed state (cut off oxygen supply), the exhaust system is in the open state, the exhaust capacity is adjusted to the extinguishing exhaust capacity value, so that the working chamber 11 of the exhaust cabinet 1 is in a negative pressure state.

[0093] In the negative pressure state, the extinguishing agent in the extinguishing device 40 is sprayed to the fire source in the working chamber 11 through the nozzle 50, and the extinguishing under negative pressure is realized, which has little effect on the laboratory environment in the cabinet and the experiment in the cabinet. After the extinguishing agent in the extinguishing device 40 is sprayed out, the pressure in the cabinet 10 of the exhaust cabinet 1 rises, reducing the possibility of toxic and harmful gas leakage in the cabinet to the laboratory space. The purpose of "extinguishing under negative pressure, effective extinguishing in the cabinet, and safety outside the cabinet" is achieved.

[0094] In some possible embodiments, when the exhaust cabinet does not include an air supply system, when the fire sensor detects the fire source in the working chamber 11, it means that the working chamber 11 of the exhaust cabinet 1 is on fire, the window 20 will move downward to close (cut off oxygen supply, prevent pollutants, and overflow of extinguishing agent), and the exhaust system is in the open state, so that the working chamber 11 of the exhaust cabinet 1 is in a negative pressure state.

[0095] Exemplarily, when any one of the photoelectric smoke detector 30, the flame detector 32, and the temperature detector 31 detects the fire source in the working chamber 11, the nozzle 50 can spray the extinguishing agent to the working chamber 11. The timeliness of the extinguishing device 40 for extinguishing the exhaust cabinet 1 is improved.

[0096] In some possible embodiments, when one of the fire sensors detects the fire source in the working chamber 11, the exhaust cabinet 1 sends an alarm signal, and the nozzle 50 in the exhaust cabinet 1 does not spray the extinguishing agent to the working chamber of the exhaust cabinet 1. In some possible embodiments, when at least two fire sensors detect the fire source in the working chamber 11, the nozzle 50 in the exhaust cabinet 1 sprays the extinguishing agent to the working chamber of the exhaust cabinet 1.

[0097] In some possible embodiments, the extinguishing agent stored in the extinguishing device 40 is perfluorohexone.

[0098] Perfluorohexanone: BI1230, named dodecafluoro-2-methyl-pentanone. Perfluorohexanone has the following characteristics: (1) Its boiling point is higher than other gaseous fire extinguishing agents. It is liquid at room temperature and is not classified as a hazardous material. It can be stored and transported in ordinary containers under normal pressure within a wide temperature range. (2) The heat of vaporization of perfluorohexanone is only 1 / 25 of that of water, while its vapor pressure is 12 times that of water. Therefore, it is easy to vaporize. Even at low temperatures (-25°C), it can effectively vaporize and diffuse into the space it protects, extinguishing the fire and protecting the safety of personnel and equipment without leaving any traces. (3) Perfluorohexanone does not contain solid particles, grease, or ozone-depleting chemicals such as chlorine and bromine. It is non-conductive, volatile, leaves no traces, is non-corrosive, and does not damage electronic components and circuits. (4) Perfluorohexanone has been approved by the U.S. Environmental Protection Agency (EPA) and meets the registration requirements of the SNAP (Significant New Alternatives Policy). It can be used in places where people are present and is harmless to the human body. Typical application areas include: fires in computer rooms, data centers, military industry, equipment warehouses, aviation, ships, vehicles, libraries, oil and gas production, etc. (5) It has no obvious chemical reaction to common metal and rubber sealing materials, does not damage electronic components and circuits, and is compatible with a wide range of structural materials.

[0099] Perfluorohexanone has excellent fire extinguishing properties. Its mechanism of action is both physical and chemical, encompassing three steps: First, cooling extinguishing. After being atomized at high speed, perfluorohexanone vaporizes upon exposure to heat. Due to its large heat of vaporization capacity and strong heat absorption capacity, it rapidly loses heat from the flame, disrupting the tetrahedral equilibrium of the fire. Second, suffocation extinguishing. Perfluorohexanone, due to its high specific gravity, isolates the oxygen in the air surrounding the flame during its suspended, falling process. Third, chemical inhibition extinguishing. It captures free radicals in the combustion chain reaction, terminating the flame propagation chain reaction. Typical design concentrations range from 4.5 to 5.9 volume percent.

[0100] In some possible implementations, reference Figure 2 、 Figure 3 、 Figure 8 、 Figure 15 As mentioned above, the nozzle 50 is located on the top wall 104 of the working chamber 11. That is, along the height of the fume hood 1, the nozzle 50 is positioned facing the bottom wall 102 of the working chamber 11. This arrangement facilitates spraying fire extinguishing agent toward the fire source within the working chamber 11, effectively extinguishing the fire. For example, the nozzle 50 is installed directly above the equipment potentially causing a fire, with the nozzle 50 facing downward. This results in a higher concentration of fire extinguishing agent and more efficient fire extinguishing.

[0101] In some possible implementations, the fire extinguishing sensor is installed directly above the potential fire equipment, with the fire extinguishing sensor facing downward. After such an arrangement, the detection distance is short and the response speed is fast.

[0102] In some possible implementations, reference Figures 6 to 11 , along the width direction of the exhaust cabinet 1 ( Figure 6 、 Figure 7 、 Figures 9 to 11 The inner width of the exhaust cabinet 1 is W; along the depth direction of the exhaust cabinet 1 ( Figure 8 The internal depth of the exhaust cabinet 1 is D; along the height direction of the exhaust cabinet 1 ( Figures 8 to 11 The internal height of the fume hood 1 is H.

[0103] Among them, along the width direction of the exhaust cabinet 1, the width of the nozzle 50 from the center line of the exhaust cabinet 1 is W1 (such as Figure 6 、 Figure 10 、 Figure 11 ), wherein 0 mm ≤ W1 ≤ 0.32 W. The center line of the fume hood 1 is, for example, a symmetrical center line along the width direction. Figure 6 、 Figure 7 Figure 10 and Figure 11 The plane A shown divides the fume hood 1 into two parts symmetrically along the width direction, and the center line of the fume hood 1 is located in the plane A. In the depth direction of the fume hood 1, the depth of the nozzle 50 from the rear wall of the fume hood 1 (i.e., the rear wall 103) is D1 (as shown in FIG. Figure 8 ), wherein 0.3D≤D1≤0.5D; along the height direction of the fume hood 1, the height of the nozzle 50 from the top cavity wall 104 of the fume hood 1 is H1 (as Figure 8 ), where 0mm

[0104] In some possible implementations, the specific number of the nozzles 50 and the specific value of the width W1 of the nozzles 50 from the center line of the fume hood 1 can be set accordingly according to the width W of the fume hood 1 .

[0105] For example, refer to Figure 9 , 0mm<W≤1200mm, the number of nozzles 50 is one, W1=0mm. That is, when the width W of the fume hood 1 is within the above range, one nozzle 50 is provided at the center line of the fume hood 1 to achieve effective fire extinguishing.

[0106] For example, refer to Figure 10 ​, 1200mm<W≤1800mm, the number of nozzles 50 is two, and the width of each nozzle 50 from the centerline of the fume hood 1 is W1, where 0.17W≤W1≤0.25W. That is, when the width W of the fume hood 1 is within the above range, two nozzles 50 are installed in the fume hood 1, and the two nozzles 50 are equidistant from the centerline A, to achieve effective fire extinguishing. For example, the width W of the fume hood 1 is 1466mm. The distance between the two nozzles 50 is 600mm.

[0107] For example, refer to Figure 11 , 1800mm<W≤2400mm, the number of nozzles 50 is three, one of which is located at the center line of the fume hood 1, and the width of each of the remaining nozzles 50 from the center line of the fume hood 1 is W1, wherein 0.25W≤W1≤0.32W. That is, when the width W of the fume hood 1 is within the above range, three nozzles 50 are arranged in the fume hood 1 to achieve effective fire extinguishing. The three nozzles 50 are arranged in a row along the width direction of the fume hood 1. The distance between two adjacent nozzles 50 is equal.

[0108] In some possible embodiments, Q min ≤Q 排 ≤N*V, where Q 排 It represents the exhaust volume of the exhaust system when the nozzle 50 sprays the fire extinguishing agent, Q min Indicates the minimum exhaust volume of the exhaust system when ensuring the minimum air change rate, N represents the air change rate of the exhaust cabinet 1, V represents the volume of the working chamber 11 of the exhaust cabinet 1 (V = W * D * H), and the minimum air change rate of the exhaust cabinet 1 is 150 times / hour. Within the above range, it is conducive to achieving a negative pressure state for the exhaust cabinet 1. In some possible embodiments, Q min =N*V=150*1.51=226.5m 3 / h, V: cabinet volume = 1.51m 3 In some possible implementations, N=200.

[0109] In some possible implementations, the capacity of the fire extinguishing agent stored in the fire extinguishing device 40 is G, where G = (V / S) × C1 × K; V represents the volume of the working chamber 11 of the fume hood 1, S represents the specific volume of the fire extinguishing agent, C1 represents the fire extinguishing design concentration or the inerting design concentration, and K represents the pressure correction factor of the room where the fume hood 1 is located. Using this fire extinguishing agent capacity calculation formula, effective fire extinguishing can be achieved in the fume hood 1.

[0110] For example, the pressure in the room is 0Pa, K=1; the pressure in the room is -2Pa, K=1.03; the pressure in the room is -5Pa, K=1.063; the pressure in the room is -8Pa, K=1.08.

[0111] For example, the amount of fire extinguishing agent G for a 1.5m exhaust cabinet 1 1.5 . V 1.5 : The internal volume is: length * width * height = 1.47m * 0.79m * 1.3m = 1.51m 3 S:0.0719m 3 / kg; C1: Fire extinguishing range 4.5%-5.9%, taking the maximum value of 5.9%; the pressure of the room is -5Pa, K is 1.063. G 1.5 =(V / S)*C1*K=(1.51 / 0.0719)*0.059*1.063=1.31kg, after adding 10% safety margin G 1.5 =1.31*(1+10%)=1.44kg.

[0112] Spray finished within 10s, calculate the flow volume Q 1.5 =V / T, V=G 1.5 / ρ. Where: V represents the volume in gas state (m 3 ), T represents the injection time s, which is 10 s here; ρ represents the density in gaseous state, which is 0.0136 g / cm 3 .Q 1.5 =(1.44 / 13.6) / 10*3600=38.1m 3 / h.

[0113] Therefore, the fire extinguishing agent dosage calculation formula mentioned above can meet the fire extinguishing agent dosage required for extinguishing the fire in the exhaust cabinet 1.

[0114] In some possible implementations, reference Figure 1 The fume hood 1 of the present application includes a controller 60, which is connected to the viewing window 20, the air supply system, the exhaust system, the fire extinguishing sensor, the nozzle 50, and the fire extinguishing device 40. The controller 60 is connected to the fire extinguishing sensor via a first cable 61. The fire extinguishing device 40 includes a fire extinguishing control valve 41, which is connected to the controller 60 via a second cable 42. Thus, when the fire extinguishing sensor detects a fire source within the fume hood 1, the controller 60 controls the viewing window 20 to move downward along the height direction of the fume hood 1, and controls the control valve 41 of the fire extinguishing device 40 so that the fire extinguishing device 40 supplies fire extinguishing agent to the nozzle 50.

[0115] In some possible implementations, the fume hood 1 of the present application further includes an audible and visual alarm, which is connected to the controller 60. When the fire extinguishing sensor detects a fire source in the fume hood 1, the controller 60 controls the audible and visual alarm to send an alarm signal.

[0116] The present application also provides a fire extinguishing method for a fume hood 1, comprising:

[0117] The fire source is detected in the working chamber 11 of the fume hood 1 , for example, by detecting the fire source in the working chamber 11 of the fume hood 1 through the fire extinguishing sensor in the above embodiment.

[0118] The window 20 of the fume hood 1 is controlled to move downwardly along the height direction of the cabinet body 10 of the fume hood 1 and close. When the fire extinguishing sensor detects a fire source in the fume hood 1, the window 20 is controlled by the controller 60 to move downwardly along the height direction of the fume hood 1 to cut off oxygen supply and prevent pollutants and fire extinguishing agent from overflowing.

[0119] The air supply system of the fume hood 1 is controlled to be in a closed state (cutting off oxygen supply), and the exhaust system of the fume hood 1 is controlled to be in an open state, so that the working chamber 11 of the fume hood 1 is in a negative pressure state. For example, the air supply system of the fume hood 1 is controlled to be in a closed state and the exhaust system of the fume hood 1 is controlled to be in an open state, so that the working chamber 11 of the fume hood 1 is in a negative pressure state, by the above-mentioned controller 60. In some possible embodiments, the fume hood 1 does not include an air supply system. Therefore, when a fire source is detected in the working chamber 11 of the fume hood 1, the exhaust system of the fume hood is controlled to be in a closed state, so that the working chamber 11 of the fume hood is in a negative pressure state.

[0120] The nozzle 50 in the working chamber 11 of the fume hood 1 is controlled to spray the fire extinguishing agent into the working chamber 11 of the fume hood 1. For example, the nozzle 50 is controlled by the controller 60 to spray the fire extinguishing agent into the working chamber 11 of the fume hood 1. The fire extinguishing agent sprayed by the nozzle 50 is, for example, perfluorohexanone.

[0121] In some possible implementations, the fire extinguishing sensor detects a fire source in the working chamber of the fume hood 1 , controls the sound and light alarm to send an alarm signal, and the nozzle 50 does not spray the fire extinguishing agent into the working chamber 11 of the fume hood 1 .

[0122] In some possible implementations, when at least two fire extinguishing sensors detect a fire source in the working chamber of the fume hood, the nozzle 50 is controlled to spray the fire extinguishing agent into the working chamber 11 of the fume hood 1, thereby preventing accidental spraying of the fire extinguishing agent.

[0123] In some possible implementations, the air supply system of the fume hood 1 is controlled to be in an off state for 60 seconds, and the exhaust system of the fume hood 1 is controlled to be in an on state for 60 seconds. Within this time parameter range, the fume hood 1 can be placed in a negative pressure state, achieving negative pressure fire extinguishing.

[0124] In some possible implementations, the nozzle 50 is controlled to spray all the fire extinguishing agent in the fire extinguishing device 40 within 10 seconds. That is, when there is a fire source in the working chamber 11 of the exhaust cabinet 1, the fire extinguishing device 40 will spray all the fire extinguishing agent within 10 seconds, thereby effectively extinguishing the fire in the exhaust cabinet 1.

[0125] The following combinationFigures 12 to 46 The extinguishing effect of the fume hood 1 of the present application in the above-mentioned embodiment is described. Two nozzles 50 are arranged in the working chamber 11 of the fume hood 1 as an example, and the example is that all the extinguishing agent 10 is sprayed out within 10 seconds.

[0126] The physical model is established: a 1.5-meter fume hood is constructed, and the window 20 is in a closed state (there is still an opening of 35 mm for indoor ventilation), as shown in Figure 15 , the distance of the window 20 from the bottom chamber wall 102 along the height direction is 35 mm. The exhaust volume Q 排 of the fume hood 1 is: 226.5 cmh, the volume flow rate of the extinguishing agent is 38.1 cmh, and the volume flow rate of each nozzle 50 is 19.05 cmh. Referring to Figure 13 , one of the nozzles 50 is 433 mm away from the left wall 105 in the width direction, and the other nozzle 50 is 433 mm away from the right wall 106 in the width direction.

[0127] The extinguishing inside the working chamber 11 of the fume hood 1 is judged: the inside is divided into two layers, and there are 9 measuring points in each layer, a total of 18 measuring points. Referring to Figure 12 , along the height direction of the fume hood 1 (indicated by the Y direction in Figure 12 ), two layers of measuring points are provided (indicated by B layer and C layer in Figure 12 ), wherein B layer is provided with 9 measuring points, respectively B1 to B9, and C layer is provided with 9 measuring points, respectively A1 to A9. In the concentration curve of each measuring point within 10s, the curve has a part with a concentration exceeding 5.9%, which indicates extinguishing.

[0128] Referring to Figure 14 , the middle measuring points of B layer and C layer (B2, B5, B8, A2, A5, A8) are located at the center line A of the fume hood 1, the left side measuring points of B layer and C layer (B1, B4, B7, A1, A4, A7) are 83 mm away from the left wall 105 in the width direction, and the right side measuring points of B layer and C layer (B3, B6, B9, A3, A6, A9) are 83 mm away from the left wall 105 in the width direction.

[0129] Referring to Figure 15 , along the height direction of the fume hood 1, the measuring points of B layer are 350 mm away from the measuring points of C layer, and the measuring points of C layer are 50 mm away from the bottom chamber wall 102. Along the depth direction of the fume hood 1, the front measuring points of B layer and C layer (B1, B2, B3, A1, A2, A3) are 150 mm away from the front wall 101, the rear measuring points of B layer and C layer (B7, B8, B9, A7, A8, A9) are 103 mm away from the rear wall 103, and the middle measuring points of B layer and C layer (B4, B5, B6, A4, A5, A6) are 224 mm away from the front measuring points of B layer and C layer.

[0130] The basis for judging the external leakage pollution of the exhaust cabinet 1 is: Figure 12 and Figure 15 Along the depth direction of the exhaust cabinet 1, three measuring points (P1, P2, P3) are arranged on the opening surface 75mm outside the window 20. The concentrations of the left (P1 measuring point), middle (P2 measuring point), and right (P3 measuring point) are measured, and the required value is not more than 10%.

[0131] Among them, the reference Figure 14 Along the width direction of the exhaust cabinet 1, the left point (P1 measuring point) is 83mm away from the left wall 1052, the right point (P3 measuring point) is 83mm away from the left wall 1052, and the middle point (P2 measuring point) is located at the center line A of the exhaust cabinet 1.

[0132] Through multiple simulations, the fire extinguishing effect of the above-mentioned exhaust cabinet 1 meets the requirements. For details, see the description of the following figure:

[0133] Figure 16 The concentration value of the P1 measuring point is shown, Figure 17 The concentration value of the P2 measuring point is shown, Figure 18 The concentration value of the P3 measuring point is shown, according to Figures 16 to 18 The concentration values of the three external measuring points are not more than 10%. Therefore, the external leakage pollution of the exhaust cabinet 1 meets the requirements.

[0134] Figure 19 The concentration value of the A1 measuring point is shown, Figure 20 The concentration value of the A2 measuring point is shown, Figure 21 The concentration value of the A3 measuring point is shown, Figure 22 The concentration value of the A4 measuring point is shown, Figure 23 The concentration value of the A5 measuring point is shown, Figure 24 The concentration value of the A6 measuring point is shown, Figure 25 The concentration value of the A7 measuring point is shown, Figure 26 The concentration value of the A8 measuring point is shown, Figure 27 The concentration value of the A9 measuring point is shown, according to Figures 19 to 27 The fire extinguishing concentration values of the nine measuring points of layer B exceed 5.9%. Therefore, effective fire extinguishing is achieved in the exhaust cabinet 1.

[0135] Figure 28 The concentration value of the B1 measuring point is shown, Figure 29 The concentration value of the B2 measuring point is shown, Figure 30 The concentration value of the B3 measuring point is shown, Figure 31 The concentration value of the B4 measuring point is shown, Figure 32 The concentration value of the B5 measuring point is shown, Figure 33 The concentration value of the B6 measuring point is shown, Figure 34The concentration value of the B7 measuring point is shown. Figure 35 The concentration value of the B8 measuring point is shown. Figure 36 The concentration value of the B9 measuring point is shown. Figures 28 to 36 As shown in FIG, the fire extinguishing concentration values ​​at the nine measuring points on the C floor exceed 5.9%. Therefore, effective fire extinguishing is achieved in the exhaust cabinet 1.

[0136] Figures 37 to 46 The isosurfaces for each second from the 1st to the 10th second are shown, respectively, when the fire extinguishing agent concentration in fume hood 1 is at 5.9%. By establishing a CFD physical model, transient analysis was performed on each measuring point inside fume hood 1. Within 10 seconds, all measuring points reached a concentration of 5.9%, indicating that the fire was extinguished. By establishing a CFD physical model, transient analysis was performed on each measuring point outside fume hood 1. Within 10 seconds, all measuring points remained below 10%, indicating that the fire was safe.

[0137] In summary, through CFD analysis, it is concluded that for the exhaust cabinet 1 of the present application, when the number of nozzles is 2 and the position of the nozzle 50 is the position of the above embodiment, the purpose of extinguishing the fire inside the exhaust cabinet 1 and ensuring safety outside the exhaust cabinet 1 can be achieved.

[0138] Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, it should be understood by those skilled in the art that the above description is provided as a further detailed description of the present invention in conjunction with specific embodiments thereof, and that the specific implementation of the present invention is not limited to these descriptions. Those skilled in the art may make various changes in form and details, including simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A fume hood, characterized in that: include: The cabinet has an inner cavity, which constitutes a working cavity; a viewing window, provided on the front wall of the cabinet, wherein the viewing window can be moved upward or downward along the height direction of the cabinet; an exhaust system for exhausting the air entering the working chamber from the working chamber, the exhaust system comprising an exhaust port, the exhaust port being arranged at the top of the fume hood; a fire extinguishing sensor, arranged on the wall of the working chamber; a fire extinguishing device, used for storing fire extinguishing agent, and arranged outside the working chamber; A nozzle is provided on the wall of the working chamber, the nozzle is downwardly arranged, and the nozzle is connected to the fire extinguishing device; wherein, The nozzle is capable of spraying fire extinguishing agent into the working chamber when the fire extinguishing sensor detects a fire source in the working chamber, and the window moves downward along the height direction of the cabinet and closes, and the exhaust system is in an open state, so that the working chamber is in a negative pressure state; The capacity of the fire extinguishing agent stored in the fire extinguishing device is G, G=(V / S)×C1×K; wherein V represents the volume of the working chamber of the exhaust cabinet, S represents the specific volume of the fire extinguishing agent, C1 represents the fire extinguishing design concentration or the inerting design concentration, and K represents the pressure correction coefficient of the room where the exhaust cabinet is located.

2. The fume hood according to claim 1, wherein: The fire extinguishing agent is perfluorohexanone.

3. The fume hood according to claim 1 or 2, characterized in that: Also includes: An air supply system is used to supply air to the working chamber. When the fire extinguishing sensor detects a fire source in the working chamber, the air supply system is in a closed state.

4. The fume hood according to claim 1 or 2, characterized in that: The nozzle is arranged on the top wall of the working chamber.

5. The fume hood according to claim 4, wherein: The internal width of the fume hood is W, the internal depth of the fume hood is D, and the internal height of the fume hood is H; Along the width direction of the fume hood, the width of the nozzle from the center line of the fume hood is W1, where 0mm≤W1≤0.32W; Along the depth direction of the fume hood, the depth of the nozzle from the rear cavity wall of the fume hood is D1, wherein 0.3D≤D1≤0.5D; Along the height direction of the fume hood, the height between the nozzle and the top cavity wall of the fume hood is H1, wherein 0mm<H1≤0.2H.

6. The fume hood according to claim 5, wherein: in, 0mm<W≤1200mm, the number of the nozzle is one, W1=0mm; or, 1200mm<W≤1800mm, the number of the nozzles is two, the width of each nozzle from the center line of the exhaust cabinet is W1, wherein 0.17W≤W1≤0.25W; or, 1800mm<W≤2400mm, the number of the nozzles is three, one of which is located at the center line of the exhaust hood, and the width of each of the remaining nozzles from the center line of the exhaust hood is W1, wherein 0.25W≤W1≤0.32W.

7. The fume hood according to any one of claims 1, 2, 5 and 6, characterized in that: Q min ≤ Q 排 ≤N*V, where Q 排 It represents the fire extinguishing exhaust volume of the exhaust system when the nozzle sprays the fire extinguishing agent, Q min It represents the minimum exhaust volume of the exhaust system when ensuring the minimum air change rate, N represents the air change rate of the exhaust cabinet, V represents the volume of the working chamber of the exhaust cabinet, and the minimum air change rate of the exhaust cabinet is 150 times / hour.

8. The fume hood according to claim 7, wherein: N=200。 9. The fume hood according to claim 8, wherein: The pressure in the room is 0Pa, K=1; the pressure in the room is -2Pa, K=1.03; the pressure in the room is -5Pa, K=1.063; the pressure in the room is -8Pa, K=1.

08.

10. The fume hood according to any one of claims 1, 2, 5, 6, 8, and 9, wherein: The fire extinguishing sensor is arranged on the top cavity wall of the working cavity and faces the bottom cavity wall of the working cavity.

11. The fume hood according to any one of claims 1, 2, 5, 6, 8, and 9, wherein: The fire extinguishing sensor includes any one or more of the following: a photoelectric smoke detector, a flame detector, and a temperature detector.

12. The fume hood according to any one of claims 1, 2, 5, 6, 8, and 9, wherein: The fume hood includes a controller, which is connected to the window, the air supply system, the exhaust system, the fire extinguishing sensor, the nozzle, and the fire extinguishing device.

13. A method for extinguishing a fire in a fume hood, applied to the fume hood according to any one of claims 1 to 12, characterized in that: include: A fire source is detected in the working chamber of the fume hood; Controlling the window of the fume hood to move downward along the height direction of the fume hood body and close; Control the exhaust system on the top of the fume hood to be in the open state so that the working chamber of the fume hood is in a negative pressure state; The nozzle in the working chamber of the fume hood is controlled to spray the fire extinguishing agent into the working chamber of the fume hood.

14. The method for extinguishing a fire in a fume hood according to claim 13, wherein: The fire extinguishing agent is perfluorohexanone.

15. The method for extinguishing a fire in a fume hood according to claim 13, wherein: The fire extinguishing method further includes: controlling the air supply system of the fume hood to be in a closed state, so that the working chamber of the fume hood is in a negative pressure state.

16. The method for extinguishing a fire in a fume hood according to claim 13, wherein: A fire extinguishing sensor detects a fire source in the working chamber of the exhaust cabinet and controls the sound and light alarm to send out an alarm signal.

17. The method for extinguishing a fire in a fume hood according to claim 13, wherein: At least two fire extinguishing sensors detect a fire source in the working chamber of the fume hood and control the nozzle to spray the fire extinguishing agent into the working chamber of the fume hood.

18. The method for extinguishing a fire in a fume hood according to claim 15, wherein: The time for controlling the air supply system of the fume hood to be in a closed state is 60 seconds, and the time for controlling the exhaust system of the fume hood to be in an open state is 60 seconds.

19. The method for extinguishing a fire in a fume hood according to any one of claims 13 to 18, characterized in that: The nozzle is controlled to spray the fire extinguishing agent in the fire extinguishing device within 10 seconds.

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