Self-cleaning laboratory ventilation cabinet

Abstract

The invention relates to a self-cleaning laboratory fume hood, which belongs to the technical field of fume hoods, and comprises a hood body, a flow guide assembly and an air draft assembly, the cabinet body is provided with an operation table and an air draft assembly, and the flow guide assembly is installed at an air inlet of the air draft assembly; the flow guide assembly comprises a mounting frame and a plurality of flow guide plates; the installation frame is installed on the side, facing the operation table top, of the cabinet body, any flow guide plate is connected with a rotating shaft, the rotating shafts are rotationally installed on the installation frame, and the adjacent flow guide plates form an air guide opening with the adjustable size at the air inlet. According to the ventilation cabinet, mechanical vibration is generated through abutting of the vibration parts when the flow guide plates are closed, pollutants are automatically shaken off, and the shaken-off pollutants are sucked away and discharged in time through an air draft system of the ventilation cabinet; therefore, efficient, automatic and secondary-pollution-free self-cleaning of the guide plate is achieved, and the fundamental defects of a traditional wiping method are overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of fume hoods, and in particular relates to a self-cleaning laboratory fume hood. Background Art

[0002] Laboratory fume hoods are essential safety equipment in research and production fields such as chemistry, biology, medicine, and materials science. Their core function is to generate stable, directional airflow through a built-in exhaust system, effectively capturing harmful gases, vapors, dust, aerosols, and other pollutants generated during experiments and rapidly exhausting them outdoors or filtering and purifying them for discharge, thereby protecting operators from exposure hazards and preventing contamination of the laboratory environment.

[0003] During long-term use, despite the continuous operation of the exhaust system, some pollutants such as volatile organic compound vapors, acidic / alkaline gas condensates, reaction residues, particulate dust, and bioaerosols will inevitably deposit, adsorb, or condense on the inner walls, deflectors, work surfaces, duct inlets, and even internal surfaces of the fume hood, such as the fan blades. The continued accumulation of such pollutants poses multiple risks: it may cause bacteria or fungi to grow in the hood environment, resulting in potential biological contamination; residual chemicals may corrode the hood and shorten the life of the equipment; and more seriously, accumulated pollutants may be released again in subsequent experiments due to disturbances, temperature changes, or chemical reactions, forming a source of cross-contamination, which not only endangers the immediate safety of operators but also affects the accuracy and repeatability of experimental results.

[0004] However, existing solutions to fume hood problems usually involve wiping with a cleaning rag, which can only transfer dust or debris from the guide plate to the cleaning rag. The cleaning rag is generally placed around the guide plate. Over time and under the influence of the surrounding environment, the debris attached to the cleaning rag will still affect the environment of the laboratory table.

[0005] Therefore, there is a need for a self-cleaning laboratory fume hood that is effective, reliable and safe. Summary of the Invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a self-cleaning laboratory fume hood. The existing method to solve the problem of fume hood is usually to wipe it with a cleaning rag, etc. This method can only transfer dust or attachments from the guide plate to the cleaning rag, and the cleaning rag is generally arranged around the guide plate. With the accumulation of time and the influence of the surrounding environment, the attachments attached to the cleaning rag will still affect the environment of the laboratory table.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A self-cleaning laboratory fume hood, comprising a cabinet body, a flow guide assembly and an exhaust assembly; the cabinet body is provided with an operating table, the cabinet body is provided with an exhaust assembly, and the flow guide assembly is installed at the air inlet of the exhaust assembly; The guide assembly includes a mounting frame and several guide plates; the mounting frame is mounted on the side of the cabinet facing the operating table, any of the guide plates is connected to a rotating shaft, the rotating shaft is rotatably mounted on the mounting frame, and adjacent guide plates form an air guide port of adjustable size at the air inlet; the rotating shaft is also provided with a vibration part, and when the guide plate closes the air guide port, it abuts against the vibration part of the adjacent rotating shaft.

[0008] Preferably, it also includes a transmission assembly, which is used to drive several of the guide plates to adjust the size of the air guide port; the transmission assembly includes a spring, a transmission rod and a driving mechanism; the cabinet is provided with a guide groove, and the transmission rod moves in the guide groove, the spring is provided in the guide groove and connected to the bottom of the transmission rod, and is used to drive the transmission rod to move upward, and the driving mechanism is used to drive the transmission rod to move downward at the top of the transmission rod; several of the rotating shafts are hinged to the transmission rod, and the transmission rod moves up and down to drive several of the guide plates to rotate along with the rotating shaft.

[0009] Preferably, the driving mechanism includes a driving motor and a cam; the driving motor is installed on the top of the mounting frame, the cam is connected to the output shaft of the driving motor, and the driving motor drives the cam to rotate in a single direction; an abutment surface is provided on the top of the transmission rod, and the abutment surface is rollingly connected to the outer periphery of the cam, for driving the guide plate to open and close for cleaning.

[0010] Preferably, the cam is composed of at least two ascending sections with openings facing outwards and two descending sections with openings facing inwards, any one of the ascending sections is located between the two descending sections, and the ascending section and the descending section have a smooth transition.

[0011] Preferably, the exhaust assembly includes an exhaust fan and an exhaust duct, the exhaust fan is installed on the top of the cabinet, and the exhaust duct is sealed and connected to the exhaust fan and extends to the installation frame.

[0012] Preferably, it also includes a detection component, which adjusts the size of the air guide port according to the concentration; the detection component also includes a concentration sensor and a control unit, the concentration sensor is used to detect the concentration of the experimental gas in real time, the concentration sensor and the drive motor are both connected to the control unit, and the control unit controls the output torque of the drive motor according to the concentration signal fed back by the concentration sensor to adjust the area of ​​the air guide port.

[0013] Preferably, in the cleaning mode, the control unit controls the rotation speed of the driving motor according to the concentration signal of the concentration sensor to control the vibration of the guide plate.

[0014] Preferably, the control unit obtains the speed signal of the driving motor in real time and calculates the vibration intensity characteristic value of the guide plate according to the speed signal, and establishes a mapping relationship between the vibration intensity characteristic value and the target power of the exhaust fan; when the guide plate closes and hits the vibration part, the operating power of the exhaust fan is dynamically increased based on the current target power.

[0015] Preferably, the vibration part protrudes from the rotating shaft, and the angle between the vibration part and the guide plate is between 160° and 170°.

[0016] Preferably, the cabinet body is further provided with a transparent glass door which is slidably provided, and the transparent glass door is located in front of the operating table.

[0017] The beneficial effects of the present invention are: This application combines the abutment of the vibrating part with the driving of the rotating shaft when the guide plate is closed to generate mechanical vibration to automatically shake off the pollutants, and uses the inherent exhaust system of the fume hood to immediately suck away and discharge the shaken pollutants, thereby achieving efficient, automatic, and secondary pollution-free self-cleaning of the guide plate. This solves the fundamental defects of traditional wiping methods and significantly improves the maintenance efficiency and environmental hygiene level of laboratory fume hoods. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the front view of the laboratory fume hood provided in one embodiment of the present invention; Figure 2 This is a schematic side cross-sectional structural diagram of a laboratory fume hood provided in one embodiment of the present invention; Figure 3 This is a schematic diagram of the connection structure of the diversion assembly provided in one embodiment of the present invention; Figure 4 A schematic diagram of a cam structure provided in one embodiment of the present invention; Figure 5 This is a schematic diagram of the vibration mode structure of the flow guide component provided in one embodiment of the present invention; Legend: 1. Cabinet; 11. Worktop; 2. Air inlet; 3. Air guide assembly; 31. Air guide plate; 32. Rotating shaft; 33. Mounting frame; 34. Vibrating part; 4. Transmission assembly; 41. Spring; 42. Transmission rod; 5. Driving mechanism; 51. Cam; 511. Rising section; 512. Descending section; 52. Driving motor; 6. Exhaust assembly. DETAILED DESCRIPTION

[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0021] like Figure 1-Figure 5 As shown, a self-cleaning laboratory fume hood includes a cabinet body 1, a flow guide component 3 and an exhaust component 6; the cabinet body 1 is provided with an operating table, the cabinet body 1 is provided with an exhaust component 6, and the flow guide component 3 is installed at the air inlet 2 of the exhaust component 6; The air guide assembly 3 includes a mounting frame 33 and a plurality of air guide plates 31. The mounting frame 33 is mounted on the side of the cabinet 1 facing the operating table 11. Each air guide plate 31 is connected to a rotating shaft 32, which is rotatably mounted on the mounting frame 33. Adjacent air guide plates 31 form an air guide port of adjustable size at the air inlet 2. The rotating shaft is also provided with a vibrating portion. When the air guide port is closed, the air guide plate 31 abuts against the vibrating portion of the adjacent rotating shaft. During the experiment, the inclination angle of each guide plate 31 is adjusted by rotating the shaft 32 to form an air guide port of a specific size between adjacent guide plates 31, ensuring that harmful gases or particulate matter are effectively sucked into the exhaust component 6; when the experiment is over or cleaning is required, the guide plate 31 is controlled to rotate in the closing direction through the rotating shaft 32; at the moment when the guide plate 31 is completely closed, the rotating shaft vibration part 34 of the adjacent guide plates 31 is mechanically abutted to generate high-frequency micro-vibration; the mechanical vibration when the guide plate 31 is closed directly peels off the pollutants without any physical contact such as wiping with a rag, eliminating the transfer path of pollutants from the source, and the pollutants that are vibrated and detached are immediately captured by the negative pressure of the exhaust component 6 and directly enter the exhaust duct to avoid being retained in any area in the cabinet 1. When the guide plate 31 is closed, a completely sealed air guide port is formed, and the high-frequency vibration of the vibration part 34 ensures that there is no escape space for pollutants, while traditional rag cleaning cannot achieve complete removal in a sealed environment.

[0022] The vibration energy is transferred to the surface through the guide plate 31, causing the attached dust, pollutants or residues to fall off due to inertia. At this time, the exhaust component 6 keeps running, and the negative pressure environment formed will directly suck the detached pollutants into the exhaust duct to prevent them from spreading secondary inside the cabinet 1 or on the laboratory table.

[0023] In summary, the contact of the vibrating portion of the closed deflector 31, combined with the drive of the rotating shaft 32, generates mechanical vibrations that automatically shake off contaminants. These are then immediately sucked away and discharged by the fume hood's inherent exhaust system, achieving efficient, automated, and secondary contamination-free self-cleaning of the deflector 31. This overcomes the fundamental drawbacks of traditional wiping methods and significantly improves laboratory fume hood maintenance efficiency and environmental hygiene.

[0024] In one embodiment, a transmission assembly 4 is further included, which is used to drive the plurality of deflectors 31 to adjust the size of the air guide port; the transmission assembly 4 includes a spring 41, a transmission rod 42, and a driving mechanism 5; the cabinet 1 is provided with a guide groove, and the transmission rod 42 moves in the guide groove. The spring 41 is arranged in the guide groove and connected to the bottom of the transmission rod 42, and is used to drive the transmission rod 42 to move upward. The driving mechanism 5 is used to drive the transmission rod 42 downward at the top of the transmission rod 42; the plurality of rotating shafts 32 are hinged to the transmission rod 42, and the transmission rod 42 moves up and down to drive the plurality of deflectors 31 to rotate along with the rotating shaft 32; The driving mechanism 5 releases the downward driving force, the elastic potential energy of the spring 41 is released, and the transmission rod 42 is pushed to move upward along the guide groove, and the rotating shafts 32 of all the deflectors 31 are driven to rotate synchronously through the hinge structure, so that the deflectors 31 are flipped upward, the opening and closing angle of the air guide port is increased, and the ventilation volume is increased; the driving mechanism 5 applies a downward driving force, overcomes the elastic force of the spring 41, and pushes the transmission rod 42 to move downward along the guide groove, driving the deflectors 31 to flip downward, the opening and closing angle of the air guide port is reduced, and the ventilation volume is reduced; the transmission rod 42 is hinged to the rotating shafts 32 of all the deflectors 31, ensuring that the up and down movement of the transmission rod 42 can simultaneously drive all the deflectors 31 to rotate, thereby achieving uniform adjustment of the size of the air guide port; As a passive mechanical element, spring 41 does not require external energy drive and achieves force transmission and storage only through its own deformation. Compared with the use of complex transmission structures such as motors and gears to achieve the "reset + adjustment" function, the spring 41 solution greatly simplifies the mechanical complexity of the transmission component 4 and reduces manufacturing costs.

[0025] The transmission assembly 4 of this embodiment adopts the "single-rod articulated linkage + spring 41-drive mechanism 5" design, which perfectly solves the key problem of precise synchronous adjustment and reliable closure of multiple guide plates 31 in a simple and efficient manner. It not only significantly improves the operational convenience, airflow control performance and reliability of the self-cleaning function of the fume hood, but also greatly reduces the complexity and cost of the system.

[0026] The traditional solution relies on the forward and reverse rotation of the motor to achieve reciprocating motion, which has the problems of complex control, low efficiency and severe wear. In one embodiment, the driving mechanism 5 includes a driving motor 52 and a cam 51. The driving motor 52 is installed on the top of the mounting frame 33, and the cam 51 is connected to the output shaft of the driving motor 52. The driving motor 52 drives the cam 51 to rotate in a single direction. An abutment surface is provided on the top of the transmission rod 42, and the abutment surface is in rolling connection with the outer periphery of the cam 51 for driving the guide plate 31 to open and close for cleaning. The driving motor 52 rotates in one direction (such as clockwise), and the cam 51 rotates in one direction. The outer periphery of the wheel 51 pushes the transmission rod 42 to abut the surface, overcomes the elastic force of the spring 41 and moves downward, and drives the guide plate 31 to flip upward around the rotating shaft 32 through the hinge structure, and the air guide port expands. The cam 51 continues to rotate to the rebound area of ​​the transmission rod 42, and the restoring force of the spring 41 pushes the transmission rod 42 to rise and reset. The guide plate 31 is pulled downward by the transmission rod 42 and the air guide port shrinks. When the guide plate 31 is closed to the minimum air guide port, the vibrating part 34 of the adjacent guide plate 31 generates high-frequency micro-vibration due to mechanical abutment, peeling off the surface pollutants, and the pollutants are immediately discharged by the exhaust component 6.

[0027] This embodiment converts the unidirectional rotation of the motor into the reciprocating opening and closing of the guide plate 31 through the cam 51-transmission rod 42 mechanism. Combined with the reset of the spring 41 and the high-frequency vibration design, it achieves the triple optimization of "simplified control - improved efficiency - enhanced cleaning", fundamentally solving the contradiction that traditional driving methods are difficult to balance reliability, response speed and cleaning effect.

[0028] In order to avoid over-reliance on the output torque of the motor to achieve high-frequency vibration cleaning of the deflector 31, in one embodiment, the cam 51 is composed of at least two rising sections 511 with openings facing outward and two descending sections 512 with openings facing inward. The driving motor 52 rotates in one direction (e.g., clockwise), and the cam 51 makes the descending section 512 contact the abutting surface of the transmission rod 42, pushing the transmission rod 42 to overcome the elastic force of the spring 41 and move downward. The deflector 31 flips upward, and the air guide port expands. Any rising section 511 is located between the two descending sections 512, and the rising section 511 and the descending section 512 have a smooth transition. The driving motor 52 rotates in one direction (clockwise). The rising section 511 of the cam 51 contacts the abutting surface of the transmission rod 42, pushing the transmission rod 42 to overcome the elastic force of the spring 41 and move downward, the guide plate 31 flips upward, and the air guide port expands. The rising section 511 and the descending section 512 can be understood as a trough and peak structure. By setting the shape of the cam 51, the dependence on the output torque of the drive motor 52 is reduced. At the same time, the multiple spaced rising sections 511 and descending sections 512 essentially convert their own rotational motion into linear motion of the transmission rod 42, and at the same time increase the rising and falling frequency of the transmission rod 42, so that a smaller output torque of the drive motor 52 can achieve high vibration efficiency.

[0029] In one embodiment, the exhaust assembly 6 includes an exhaust fan and an exhaust duct. The exhaust fan is installed on the top of the cabinet 1. It takes advantage of the natural rise of hot air to preferentially extract high-temperature or harmful gases above the operating table 11, thereby improving exhaust efficiency. The exhaust duct and the exhaust fan are sealed and extended to the mounting frame 33, forming a short and straight airflow path, reducing wind resistance and ensuring that the suction force is concentrated in the area of ​​the guide plate 31. In cleaning mode, the exhaust fan runs continuously to form a negative pressure environment in the cabinet 1. The guide plate 31 is adjusted to the required angle to form an air guide port. After the air flow is guided by the guide plate 31, it is quickly sucked to the outside along the exhaust duct to prevent harmful gases from spreading in the cabinet 1; when the guide plate 31 is closed to the minimum air guide port, the exhaust fan runs to form a local negative pressure area at the air guide port, and the pollutants removed by vibration are immediately sucked into the exhaust duct to prevent secondary diffusion.

[0030] Traditional exhaust components 6 mostly adopt a side suction structure, which has problems such as long path, high leakage rate, and inability to link with the guide plate 31; this embodiment upgrades "passive exhaust" to "active diversion-precise suction-adaptive adjustment" through a top exhaust fan, a short straight pipe, a sealed connection and variable frequency control.

[0031] Fixed air ducts cannot respond to sudden changes in the test gas concentration, resulting in insufficient extraction at high concentrations, pollutant escape, and energy waste at low concentrations. In one embodiment, a detection component is further included, which adjusts the size of the air duct according to the concentration; the detection component also includes a concentration sensor and a control unit. The concentration sensor is used to detect the concentration of the test gas. The concentration sensor and the drive motor 52 are both connected to the control unit. The control unit controls the output torque of the drive motor 52 according to the concentration signal fed back by the concentration sensor to adjust the area of ​​the air duct. The concentration sensor detects the gas concentration in cabinet 1 in real time and transmits it to the control unit. The control unit runs a PID algorithm to compare the real-time concentration with the preset safety threshold, calculates the required air vent opening and closing angle, and outputs a PWM signal to adjust the output torque of the drive motor 52. The drive transmission component 4 drives the deflector 31 to rotate, precisely adjusting the air vent area. At the same time, the exhaust component 6 synchronously adjusts the exhaust volume through the inverter, forming a closed-loop system of "concentration sensing-diversion adjustment-exhaust coordination." Safety performance has been significantly improved, and it can respond to sudden concentration changes in real time. At high concentrations, the air vents are automatically expanded and the exhaust volume is increased to ensure that pollutants do not escape. At low concentrations, the air vents are reduced to reduce energy consumption. At the same time, operational convenience is optimized, no manual intervention is required, and it is compatible with complex scenarios such as sudden leaks.

[0032] In one embodiment, in the cleaning mode, the control unit controls the rotation speed of the drive motor 52 according to the concentration signal of the concentration sensor to control the vibration of the guide plate 31. When the guide plate 31 needs to be cleaned, the cleaning mode is entered from the exhaust mode or directly started. In the initial stage: the control unit allows the drive motor 52 to run at a preset basic speed to drive the rotating shaft 32 to rotate. Since the vibrating parts abut against each other, the rotation is hindered, which is converted into a mechanical vibration of basic intensity and transmitted to all the guide plates 31. During the vibration cleaning process, the concentration sensor continuously monitors the signal of pollutants or dust in the airflow in real time. The control unit compares and analyzes the received real-time concentration signal with the preset target value or threshold value. The concentration sensor transmits the detected real-time concentration signal to the control unit. In the high concentration stage: When it is detected that the concentration signal is significantly higher than the preset threshold, indicating that a large amount of attachments are being shaken off, the control unit will increase the speed of the drive motor 52. The higher speed makes the rotating shaft 32 try to rotate with greater force and higher frequency at the abutment point, and the vibration intensity transmitted to the guide plate 31 is enhanced, which can more effectively shake off stubborn, highly adhesive or thickly accumulated pollutants; as the cleaning progresses, the pollutants shaken off gradually decrease, and the concentration signal begins to decrease. When the concentration signal approaches or falls below the preset threshold, indicating that the main pollutants have been removed and only a small amount of residue or background level remains, the control unit will reduce the speed of the drive motor 52, and the cleaning is completed. During the entire vibration cleaning process, the dust and attachments that are shaken off are immediately sucked into the air guide area under the strong negative pressure generated by the continuously running exhaust component 6, and are completely discharged from the fume hood system with the exhaust air flow.

[0033] The embodiment elevates the self-cleaning function to a new level of intelligence and adaptability by introducing real-time feedback from the concentration sensor and a control strategy that dynamically adjusts the speed of the drive motor 52 based on the feedback. It not only solves the problems of inefficiency or excessive wear that may be caused by fixed vibration intensity in the basic solution, but also can "apply force on demand" according to the actual pollution removal effect, thereby achieving the comprehensive goals of maximizing cleaning efficiency, minimizing energy consumption, and optimizing equipment wear.

[0034] In one embodiment, the control unit obtains the speed signal of the drive motor 52 in real time and calculates the vibration intensity characteristic value of the deflector 31 based on the speed signal, and establishes a mapping relationship between the vibration intensity characteristic value and the target power of the exhaust fan. When the deflector 31 closes and hits the vibration part, the operating power of the exhaust fan is dynamically increased based on the current target power. The control unit collects the speed signal of the drive motor 52 in real time, calculates the vibration frequency and amplitude of the guide plate 31, and generates a vibration intensity characteristic value; and based on the preset mapping relationship, the control unit outputs a PWM signal to the exhaust fan to dynamically adjust the operating power of the exhaust fan; when the guide plate 31 closes and hits the vibration part, the system detects an increase in vibration intensity and immediately increases the exhaust fan power to the target value in the current mapping relationship, forming a strong negative pressure area to ensure that the vibrated pollutants are discharged immediately; during the cleaning process, the vibration intensity changes are continuously monitored, and the exhaust power is adjusted every 1 second to form a "vibration intensity-exhaust power" real-time matching closed loop.

[0035] In one embodiment, the vibration portion protrudes from the rotating shaft 32, and the angle between the vibration portion and the guide plate is between 160° and 170°, so that the guide plate 31 can be closed normally and can abut against the vibration portion when closed. Specifically, the guide plate 31 and the vibration portion are arranged at both ends of the rotating shaft, that is, the guide plate 31 is not symmetrically distributed on both sides of the rotating shaft 32, but is arranged on the other half of the rotating shaft. In this way, the protrusion of the adjacent rotating shaft 32 abuts the guide portion of the rotating shaft 32, thereby making the structure simple and efficient. If The vibration part on the abutting side is on the rotating shaft 32, and the angle between it and the guide plate 31 which is also set on the rotating shaft 32 is 160°-170°, so as to ensure the effective abutment between the guide plate 31 and the vibration part. If the angle is less than 160°, the guide plate 31 will collide and interfere with the vibration part or adjacent components too early during the closing process, resulting in failure to completely close; and if the angle is greater than 170°, the contact between the vibration part 34 and the adjacent guide plate 31 will become too weak or unstable during closing, and the vibration energy cannot be effectively transmitted, resulting in low cleaning efficiency.

[0036] In one embodiment, the cabinet 1 is further provided with a transparent glass door for sliding. The transparent glass door is located in front of the operating table 11. The transparent glass door is installed on the front side of the cabinet 1 through a sliding mechanism and can be electrically raised and lowered along the height direction of the operating table 11. The door is made of tempered glass and coated with an explosion-proof film, which has both light transmittance and safety. When the door is closed, it forms an airtight structure with the cabinet 1. The sliding design allows the door to be partially opened, taking into account both operational convenience and pollutant barrier effect.

[0037] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A self-cleaning laboratory fume hood, characterized in that: It includes a cabinet, a guide assembly and an exhaust assembly; the cabinet is provided with an operating table, the cabinet is provided with an exhaust assembly, and the guide assembly is installed at the air inlet of the exhaust assembly; The guide assembly includes a mounting frame and several guide plates; the mounting frame is mounted on the side of the cabinet facing the operating table, any of the guide plates is connected to a rotating shaft, the rotating shaft is rotatably mounted on the mounting frame, and adjacent guide plates form an air guide port of adjustable size at the air inlet; the rotating shaft is also provided with a vibration part, and when the guide plate closes the air guide port, it abuts against the vibration part of the adjacent rotating shaft.

2. A self-cleaning laboratory fume hood according to claim 1, characterized in that: It also includes a transmission assembly, which is used to drive several of the guide plates to adjust the size of the air guide port; the transmission assembly includes a spring, a transmission rod and a driving mechanism; the cabinet is provided with a guide groove, and the transmission rod moves in the guide groove, the spring is provided in the guide groove and connected to the bottom of the transmission rod, and is used to drive the transmission rod to move upward, and the driving mechanism is used to drive the transmission rod to move downward at the top of the transmission rod; several of the rotating shafts are hinged to the transmission rod, and the transmission rod moves up and down to drive several of the guide plates to rotate along with the rotating shaft.

3. A self-cleaning laboratory fume hood according to claim 2, characterized in that: The driving mechanism includes a driving motor and a cam; the driving motor is installed on the top of the mounting frame, the cam is connected to the output shaft of the driving motor, and the driving motor drives the cam to rotate in a single direction; an abutment surface is provided on the top of the transmission rod, and the abutment surface is rollingly connected to the outer periphery of the cam, for driving the guide plate to open and close for cleaning.

4. A self-cleaning laboratory fume hood according to claim 1, characterized in that: The cam is composed of at least two ascending sections with outward openings and two descending sections with inward openings. Any ascending section is located between the two descending sections, and the ascending section and the descending section have a smooth transition.

5. A self-cleaning laboratory fume hood according to claim 3, characterized in that: The exhaust assembly includes an exhaust fan and an exhaust duct. The exhaust fan is installed on the top of the cabinet. The exhaust duct is sealed and connected to the exhaust fan and extends to the installation frame.

6. A self-cleaning laboratory fume hood according to claim 5, characterized in that: It also includes a detection component, which adjusts the size of the air guide port according to the concentration; the detection component also includes a concentration sensor and a control unit, the concentration sensor is used to detect the concentration of the experimental gas in real time, the concentration sensor and the drive motor are both connected to the control unit, and the control unit controls the output torque of the drive motor according to the concentration signal fed back by the concentration sensor to adjust the area of ​​the air guide port.

7. A self-cleaning laboratory fume hood according to claim 6, characterized in that: In the cleaning mode, the control unit controls the rotation speed of the driving motor according to the concentration signal of the concentration sensor to control the vibration of the guide plate.

8. A self-cleaning laboratory fume hood according to claim 7, characterized in that: The control unit obtains the speed signal of the driving motor in real time and calculates the vibration intensity characteristic value of the guide plate according to the speed signal, and establishes a mapping relationship between the vibration intensity characteristic value and the target power of the exhaust fan; when the guide plate closes and hits the vibration part, the operating power of the exhaust fan is dynamically increased based on the current target power.

9. A self-cleaning laboratory fume hood according to claim 1, characterized in that: The vibration part protrudes from the rotating shaft, and the angle between the vibration part and the guide plate is between 160° and 170°.

10. A self-cleaning laboratory fume hood according to claim 1, characterized in that: The cabinet body is also slidably provided with a transparent glass door, and the transparent glass door is located in front of the operating table.

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