Ventilation cabinet structure

Abstract

The ventilation cabinet structure comprises a bottom frame and a cabinet body, the cabinet body is fixed at the upper end of the bottom frame, the cabinet body is provided with an operation area with an opening in the front side, a protective door capable of sliding up and down is arranged on the front side of the cabinet body, a gas collecting hood communicated with the operation area is fixed at the upper end of the cabinet body, and a flow guide plate is installed in the operation area. A pulley assembly is further arranged at the upper end of the cabinet body, a transmission belt is connected to the upper end of the protective door, one end of the transmission belt bypasses the pulley assembly and then is connected with a balance weight, and the pulley assembly is controlled by a driving motor installed on the cabinet body. The front side of the cabinet body is also provided with a human body induction sensor. The bottom of the cabinet body is provided with a limit switch used for contacting with the protective door. The utility model has the advantages of energy conservation and convenient operation.

Description

Technical Field

[0001] The utility model relates to the technical field of laboratory equipment, and particularly relates to a fume hood structure. Background Art

[0002] As an important safety protection equipment in the laboratory, the fume hood plays a key role in experimental environments such as chemistry, biology, and medicine. Its main function is to timely discharge harmful gases, vapors, and particulate matters generated during the experiment through forced ventilation, protecting the operators from chemical substances. As the core component of the fume hood, the protective door controls the air flow speed and exhaust air volume by adjusting the opening area, effectively reducing the leakage of harmful gases to the laboratory and ensuring the safety of the experimental environment. With the continuous improvement of laboratory safety requirements and the in-depth promotion of the concept of energy conservation and emission reduction, higher requirements are put forward for the intelligence and automation of fume hood equipment.

[0003] The protective doors of fume hoods in the prior art mainly adopt manual operation methods, and realize up and down sliding through a counterweight balance system or a spring assist mechanism. The operator manually adjusts the opening height of the protective door according to the experimental needs to obtain appropriate face air velocity and ventilation effect. Some high-end products are equipped with an electric drive device, and the lifting of the protective door can be controlled by a button, but still requires manual judgment and operation.

[0004] However, the above-mentioned prior art solutions expose many problems in practical applications. The biggest drawback of the manual operation method is that it completely depends on the subjective awareness of the operator. When the operator leaves the experimental area, they often forget to close the protective door, resulting in the fume hood running at a high energy consumption for a long time. The energy consumption when the protective door is fully open is usually several times that when it is closed, causing serious energy waste. Even for products equipped with an electric drive device, due to the lack of an automatic sensing function, there are also problems of untimely manual operation. In addition, manual operation is extremely inconvenient when both hands are occupied, affecting the smoothness and efficiency of experimental operations. Although the existing button control method has improved, it is still not intelligent enough and cannot automatically adjust the operation mode according to the personnel activity status, and fails to fundamentally solve the problems of energy consumption and convenience. Content of the Utility Model

[0005] The purpose of the utility model is to provide a fume hood structure, which can achieve energy conservation and convenient operation.

[0006] To achieve the above object, the present utility model provides the following technical solution: A fume hood structure, comprising a bottom frame and a cabinet body. The cabinet body is fixed to the upper end of the bottom frame. The cabinet body has an operation area with an opening at the front side. A protective door that can slide up and down is provided on the front side of the cabinet body. A gas collecting hood connected to the operation area is fixed to the upper end of the cabinet body. A flow guide plate is installed in the operation area. An exhaust passage connected to the gas collecting hood is formed between the flow guide plate and the cabinet body. A pulley assembly is further provided at the upper end of the cabinet body. The upper end of the protective door is connected to a transmission belt. One end of the transmission belt bypasses the pulley assembly and is connected to a counterweight. The pulley assembly is controlled by a driving motor installed on the cabinet body. A human body induction sensor is also installed on the front side of the cabinet body. A limit switch for contacting the protective door is provided at the bottom of the cabinet body. The human body induction sensor, the limit switch, and the driving motor are respectively electrically connected to a control module. When the human body induction sensor detects that a person has left, the control module controls the driving motor to rotate, driving the protective door to descend to the closed position. When the protective door contacts the limit switch, the control module controls the driving motor to stop working.

[0007] Preferably, the cabinet body includes a left side plate, a right side plate, a back plate, a top plate, and a physicochemical board tabletop. The left side plate is vertically fixed to the left end of the bottom frame. The right side plate is vertically fixed to the right end of the bottom frame. The back plate is vertically fixed to the rear end of the bottom frame and is fixedly connected to the rear ends of the left side plate and the right side plate. The top plate is horizontally fixed to the upper ends of the left side plate, the right side plate, and the back plate. The physicochemical board tabletop is horizontally fixed to the upper surface of the bottom frame. A left maintenance plate is vertically fixed to the left end of the physicochemical board tabletop. A first chamber for accommodating pipelines is formed between the left maintenance plate and the left side plate. A right maintenance plate is vertically fixed to the right end of the physicochemical board tabletop. A second chamber for accommodating pipelines is formed between the right maintenance plate and the right side plate.

[0008] Preferably, first profiles are vertically provided at both the left and right ends on the front side of the cabinet body. The left and right side edges of the protective door are respectively in sliding fit with the corresponding first profiles. Second profiles are vertically fixed to both the left and right ends on the rear side of the cabinet body. The second profiles are arranged parallel to the first profiles. The left and right ends of the counterweight are respectively in sliding fit with the corresponding second profiles.

[0009] Preferably, the pulley assembly includes two first pulleys and two second pulleys. A first rotating shaft is rotatably arranged between the two first profiles, and the two first pulleys are respectively fixed at both ends of the first rotating shaft. A second rotating shaft is rotatably arranged between the two second profiles, and the two second pulleys are respectively fixed at both ends of the second rotating shaft. Two transmission belts are connected to the upper end of the protective door, and each transmission belt bypasses the corresponding first pulley and second pulley. The driving motor is in transmission connection with the first rotating shaft or the second rotating shaft.

[0010] Preferably, the counterweight is connected to the two transmission belts through a connecting piece. Rollers are arranged on both sides of the counterweight, and the rollers are in rolling fit with the corresponding second profiles.

[0011] Preferably, the bottom opening of the air collecting hood is communicated with the top of the operation area. An exhaust interface is arranged at the top of the air collecting hood, and the exhaust interface is used for connecting an external exhaust duct. The flow guide plate includes a vertical flow guide plate and an inclined flow guide plate. The vertical flow guide plate is vertically arranged at the rear side of the operation area, and a plurality of through grooves are formed in the vertical flow guide plate. The lower end of the inclined flow guide plate is connected to the upper end of the vertical flow guide plate, and the inclined flow guide plate is inclined downward from front to back. A gap is left between the upper end of the inclined flow guide plate and the top plate.

[0012] Preferably, an LED lighting lamp is arranged at the inner top of the cabinet body. The LED lighting lamp is electrically connected to the control module. When the human body induction sensor detects that a person is approaching, the control module controls the LED lighting lamp to light up. When the protective door descends to the closed position, the control module controls the LED lighting lamp to turn off.

[0013] Preferably, a movable experimental cabinet is arranged in the bottom frame.

[0014] Compared with the prior art, the advantages of the present utility model are as follows: The device of the present utility model monitors the presence state of the operator in real time through the human body induction sensor. When it detects that a person leaves the operation area, the control module automatically starts the driving motor, drives the transmission belt to operate through the pulley assembly, and uses the gravity of the counterweight to make the protective door smoothly descend to the closed position, effectively closing the operation area. When the protective door descends in place and touches the limit switch, the control module immediately controls the driving motor to stop working, ensuring the accurate positioning of the protective door.

[0015] The automated control of this structure significantly improves the operational convenience, avoiding the tediousness of manual operation. The automatic closing of the protective door after personnel leave can effectively prevent the leakage of harmful gases and ensure the safety of the laboratory environment. Through the coordinated action of the air collection hood, the flow guide plate, and the exhaust channel, an efficient air flow organization system is formed to ensure the full collection and elimination of harmful substances. The combined design of the counterweight and the drive motor not only ensures the stability of the protective door operation but also provides reliable power support. The setting of the limit switch avoids equipment damage caused by excessive downward pressure of the protective door, improving the reliability and service life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 Schematic three-dimensional structure diagram of the present invention;

[0018] Figure 2 Top view of the present invention;

[0019] Figure 3 Cross-sectional view of the present invention;

[0020] Figure 4 Schematic diagram of the internal structure of the present invention;

[0021] Figure 5 Schematic three-dimensional structure diagram of the counterweight in the present invention;

[0022] Figure 6 Principle block diagram of the circuit part of the present invention;

[0023] In the figures, 1, bottom frame; 2, cabinet body; 3, operation area; 4, protective door; 5, air collection hood; 6, pulley assembly; 7, transmission belt; 8, counterweight; 9, drive motor; 10, human body induction sensor; 11, limit switch; 12, control module; 13, left side plate; 14, right side plate; 15, back plate; 16, top plate; 17, physical and chemical board tabletop; 18, left maintenance board; 19, first chamber; 20, right maintenance board; 21, first profile; 22, second profile; 23, first pulley; 24, second pulley; 25, second chamber; 26, first rotating shaft; 27, second rotating shaft; 28, connecting piece; 29, roller; 30, exhaust interface; 31, vertical flow guide plate; 32, inclined flow guide plate; 33, through groove; 34, LED lighting lamp; 35, experimental cabinet. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Next, in combination with the accompanying drawings in the embodiments of the present utility model, the technical solutions in the embodiments of the present utility model will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0025] Embodiment 1: As Figures 1 - 6 shown, a fume hood structure includes a bottom frame 1 and a cabinet body 2. The cabinet body 2 is fixed to the upper end of the bottom frame 1. The cabinet body 2 has an operation area 3 with an opening at the front side. A protective door 4 that can slide up and down is arranged on the front side of the cabinet body 2. An air collecting hood 5 connected to the operation area 3 is fixed to the upper end of the cabinet body 2. A flow guide plate is installed in the operation area 3, and an exhaust passage connected to the air collecting hood 5 is formed between the flow guide plate and the cabinet body 2. A pulley assembly 6 is further arranged at the upper end of the cabinet body 2. One end of a transmission belt 7 is connected to the upper end of the protective door 4. After one end of the transmission belt 7 bypasses the pulley assembly 6, it is connected to a counterweight 8. The pulley assembly 6 is controlled by a driving motor 9 installed on the cabinet body 2. A human body induction sensor 10 is also installed on the front side of the cabinet body 2. A limit switch 11 for contacting the protective door 4 is arranged at the bottom of the cabinet body 2. The human body induction sensor 10, the limit switch 11, and the driving motor 9 are respectively electrically connected to a control module 12. When the human body induction sensor 10 detects that a person has left, the control module 12 controls the driving motor 9 to rotate, driving the protective door 4 to descend to the closed position. When the protective door 4 contacts the limit switch 11, the control module 12 controls the driving motor 9 to stop working.

[0026] When the human body induction sensor 10 detects that there is no personnel activity in the operation area 3 and continues to delay for 3 - 5 seconds, the control module 12 issues a descent command. The driving motor 9 drives the pulley assembly 6 to rotate. The transmission belt 7 runs smoothly under the dual action of the gravity of the counterweight 8 and the driving force of the motor. The protective door 4 descends at a constant speed of 0.1 - 0.3 m / s. The weight of the counterweight 8 is usually designed to be 80 - 120% of the weight of the protective door 4 to ensure the safe operation of the system in the power-off state. When the protective door 4 approaches the closed position, the limit switch 11 detects the in-place signal of the protective door 4, and the control module 12 immediately executes a soft stop program, first reducing the motor speed and then completely stopping to avoid impact.

[0027] The human body induction sensor 10 uses a PIR pyroelectric infrared sensor or a microwave Doppler sensor, with a detection accuracy capable of detecting human activities within a range of 0.5 meters, a response time of less than 1 second. The control module 12 uses a 32-bit ARM microprocessor, which can accurately control the start, stop, and rotation speed of the drive motor 9 according to the sensor feedback signal. The drive motor 9 is selected as a stepper motor or a servo motor, with a power usually of 50 - 100W, and has high-precision positioning ability and low-noise characteristics.

[0028] Embodiment 2: As Figures 1 - 6 shown, different from Embodiment 1, the cabinet 2 includes a left side plate 13, a right side plate 14, a back plate 15, a top plate 16, and a chemical-resistant board tabletop 17. The left side plate 13 is vertically fixed at the left end of the bottom frame 1, the right side plate 14 is vertically fixed at the right end of the bottom frame 1, the back plate 15 is vertically fixed at the rear end of the bottom frame 1 and is fixedly connected to the rear ends of the left side plate 13 and the right side plate 14. The top plate 16 is horizontally fixed at the upper ends of the left side plate 13, the right side plate 14, and the back plate 15. The chemical-resistant board tabletop 17 is horizontally fixed on the upper surface of the bottom frame 1. A left maintenance board 18 is vertically fixed at the left end of the chemical-resistant board tabletop 17, and a first chamber 19 for accommodating pipelines is formed between the left maintenance board 18 and the left side plate 13. A right maintenance board 20 is vertically fixed at the right end of the chemical-resistant board tabletop 17, and a second chamber 25 for accommodating pipelines is formed between the right maintenance board 20 and the right side plate 14.

[0029] The left side plate 13, the right side plate 14, and the back plate 15 form a three-sided enclosure structure, which uses phenolic resin plates or stainless steel plates with a thickness of 12 - 15mm, and has excellent corrosion resistance and mechanical strength. The top plate 16 serves as a load-bearing structure, which not only bears the weight of the air collection hood 5 and the pulley assembly 6, but also provides a stable support platform for the installation of internal equipment. The chemical-resistant board tabletop 17 is selected from epoxy resin plates or ceramic plates, with a thickness usually of 20 - 25mm, and has the characteristics of acid and alkali resistance, high temperature resistance, and easy cleaning, and can withstand the erosion of various chemical reagents.

[0030] The widths of the first chamber 19 and the second chamber 25 are usually 80 - 120mm, which are specifically used for arranging service facilities such as water supply and drainage pipelines, gas pipelines, and cable harnesses. The two maintenance boards adopt an openable design and are equipped with detachable inspection boards, which can be easily opened for pipeline maintenance or replacement during maintenance.

[0031] In this embodiment, first profiles 21 are vertically arranged at both the left and right ends of the front side of the cabinet 2, and the left and right side edges of the protective door 4 are respectively in sliding fit with the corresponding first profiles 21. Second profiles 22 are vertically fixed at both the left and right ends of the rear side of the cabinet 2, and the second profiles 22 are arranged in parallel with the first profiles 21. The left and right ends of the counterweight 8 are respectively in sliding fit with the corresponding second profiles 22.

[0032] The first profile 21 is arranged at the left and right ends of the front side of the cabinet body 2, providing vertical movement guidance for the protective door 4. The left and right side edges of the protective door 4 form a sliding fit relationship with the first profile 21, and the movement track of the protective door 4 is controlled through the fit clearance. The second profile 22 is fixed at the left and right ends of the rear side of the cabinet body 2, arranged in parallel with the first profile 21, providing guiding support for the vertical movement of the counterweight 8. The left and right ends of the counterweight 8 are respectively in sliding fit with the corresponding second profile 22, ensuring that the counterweight 8 maintains a stable movement state during the lifting process.

[0033] Through the front and rear double guide rail structures, this guiding system forms a stable four-point constraint mechanism. When the driving motor 9 is started, the transmission belt 7 drives the protective door 4 to slide vertically along the first profile 21. At the same time, the counterweight 8 moves synchronously along the second profile 22, and the two maintain movement synchronism through the transmission belt 7. The parallel arrangement of the first profile 21 and the second profile 22 ensures that the transmission belt 7 maintains a constant tension and direction during operation, avoiding uneven loading and jamming caused by non-parallel guide rails. The design of the sliding fit effectively restricts the movement of the protective door 4 and the counterweight 8 during the movement process, preventing lateral swing and torsional deformation. When the protective door 4 descends to the closed position, the first profile 21 continues to provide precise positioning for the protective door 4, ensuring that the protective door 4 is closely attached to the sealing surface of the cabinet body 2.

[0034] In this embodiment, the pulley assembly 6 includes two first belt pulleys 23 and two second belt pulleys 24. A first rotating shaft 26 is rotatably arranged between the two first profiles 21, and the two first belt pulleys 23 are respectively fixed at both ends of the first rotating shaft 26. A second rotating shaft 27 is rotatably arranged between the two second profiles 22, and the two second belt pulleys 24 are respectively fixed at both ends of the second rotating shaft 27. The upper end of the protective door 4 is connected with two transmission belts 7, and each transmission belt 7 bypasses the corresponding first belt pulley 23 and second belt pulley 24. The driving motor 9 is in transmission connection with the first rotating shaft 26 or the second rotating shaft 27.

[0035] In the above structure, the first rotating shaft 26 is horizontally installed between the two first profiles 21, and is rotatably connected through a bearing seat. The two first belt pulleys 23 are respectively fixed at both ends of the first rotating shaft 26. The diameter of the belt pulley is 80 - 120 mm, made of aluminum alloy material, and a V-profile is arranged on the wheel rim, with a groove depth of 5 - 8 mm to ensure the stable meshing of the transmission belt 7. The second rotating shaft 27 is installed between the two second profiles 22, parallel to the first rotating shaft 26, and the parallelism error is controlled within ±2 mm. The two second belt pulleys 24 are fixed at both ends of the second rotating shaft 27, forming a transmission pair with the first belt pulley 23.

[0036] The upper end of the protective door 4 is connected to two transmission belts 7. The transmission belts 7 are made of polyurethane material with a tensile strength of not less than 1000 N. Each transmission belt 7 bypasses the corresponding first pulley 23 and second pulley 24 to form a closed loop, with one end connected to the protective door 4 and the other end connected to the counterweight 8. The drive motor 9 is in transmission connection with the first rotating shaft 26 or the second rotating shaft 27. The motor output torque is transmitted to the pulley through the rotating shaft to drive the movement of the transmission belt 7. The double-pulley design ensures that the driving force is evenly distributed, avoiding the inclination or jamming of the protective door 4 caused by unilateral force. When the drive motor 9 rotates forward, the first pulley 23 drives the transmission belt 7 to raise the protective door 4 and lower the counterweight 8; when the drive motor 9 rotates in reverse, the protective door 4 descends and the counterweight 8 ascends. This transmission system has a stable transmission ratio, low noise, and is easy to maintain, capable of achieving precise positioning and smooth operation of the protective door 4.

[0037] Embodiment 3: As Figures 1 - 6 shown, different from Embodiment 2, the counterweight 8 is connected to the two transmission belts 7 through the connecting piece 28. Both sides of the counterweight 8 are provided with rollers 29, and the rollers 29 are in rolling fit with the corresponding second profile 22.

[0038] In the above structure, the upper end of the connecting piece 28 is provided with a fixed point for the transmission belt 7, and the two transmission belts 7 are firmly fixed by clamps or bolts to ensure stable and reliable force transmission between the transmission belt 7 and the counterweight 8. At least one roller 29 is provided on each side of the counterweight 8. The roller 29 adopts a polyurethane-coated bearing structure with an outer diameter of 40 - 60 mm, and the bearing is a deep groove ball bearing, which has good load-bearing capacity and rotational performance. The rolling fit has the advantages of small frictional resistance, low wear, and smooth operation compared with the sliding fit, effectively reducing the movement resistance of the counterweight 8 during the lifting and lowering process.

[0039] In this embodiment, the bottom opening of the air hood 5 is connected to the top of the operation area 3. The top of the air hood 5 is provided with an exhaust interface 30 for connecting to an external exhaust duct. The deflector includes a vertical deflector 31 and an inclined deflector 32. The vertical deflector 31 is vertically arranged at the rear side of the operation area 3, and a plurality of through slots 33 are opened on the vertical deflector 31. The lower end of the inclined deflector 32 is connected to the upper end of the vertical deflector 31, and the inclined deflector 32 is inclined downward from front to back. There is a gap between the upper end of the inclined deflector 32 and the top plate 16.

[0040] In the above structure, the air hood 5 forms a direct connection with the top of the operation area 3 through the bottom opening to ensure the effective collection of harmful gases. A rectifying device is arranged inside the air hood 5 to make the air flow evenly distributed through a perforated plate or honeycomb plate structure, avoiding local turbulence and dead corners. The exhaust interface 30 is located at the central position of the top of the air hood 5 and is connected to the external exhaust duct through a flange. A sealing gasket is provided at the connection to ensure good airtightness.

[0041] The vertical baffle 31 is vertically installed at the rear of the operation area 3, and the plate surface is parallel to the back plate 15 with an appropriate distance maintained. A plurality of through slots 33 are provided on the vertical baffle 31 to provide a channel for the air flow while increasing the flow resistance, so that the air flow velocity tends to be uniform. The inclined baffle 32 is distributed obliquely backward and downward. The design of the inclination angle takes into account both the air flow guiding effect and the structural compactness. An appropriate gap is reserved between the upper end of the baffle and the top plate 16 to form a pressure equalizing chamber, so that the air flow can be further rectified before entering the exhaust channel. This gap design facilitates the installation and maintenance of the baffle.

[0042] In this embodiment, an LED lighting lamp 34 is provided at the inner top of the cabinet body 2. The LED lighting lamp 34 is electrically connected to the control module 12. When the human body induction sensor 10 detects that a person is approaching, the control module 12 controls the LED lighting lamp 34 to light up. When the protection door 4 descends to the closed position, the control module 12 controls the LED lighting lamp 34 to turn off.

[0043] In the above structure, the LED lighting lamp 34 is installed at the inner top of the cabinet body 2 to provide sufficient and uniform lighting for the experimental operation. The LED light source has the characteristics of high luminous efficiency, long service life, and low heat generation, avoiding the problems of stroboscopic and light decay of traditional fluorescent tubes. The lighting fixture adopts an anti-corrosion shell design, which can resist the erosion of laboratory chemical gases and ensure long-term stable operation.

[0044] The control module 12 is connected to the LED lighting lamp 34 through a cable to realize the intelligent control of the lighting system. When the human body induction sensor 10 detects that an operator is approaching the fume hood, the control module 12 immediately issues a lighting instruction, and the LED lighting lamp 34 starts instantly. It has a fast response speed and does not require a preheating time. The linkage design of the lighting system and the human body induction system avoids the cumbersome operation of manually turning on and off the lighting, significantly improving the use convenience. When the protection door 4 completely descends to the closed position, the control module 12 automatically turns off the LED lighting lamp 34 to achieve effective energy-saving control.

[0045] The automatic opening and closing function of this intelligent lighting system reduces unnecessary energy consumption and prolongs the service life of the LED light source. The instant response lighting control improves the operation environment, experimental efficiency and safety.

[0046] In this embodiment, a movable experimental cabinet 35 is provided inside the bottom frame 1.

[0047] The experimental cabinet 35 is arranged inside the bottom frame 1 and adopts a movable design. It can be flexibly moved through universal wheels. The experimental cabinet 35 has an independent cabinet body 2 structure, including components such as a frame, drawers and cabinet doors, providing a dedicated storage space for experimental equipment and reagents. The frame of the cabinet body 2 is made of metal material, with good load-bearing capacity and structural stability, and can bear the weight of experimental equipment and reagents.

[0048] In this embodiment, an operation panel is fixed to the front side of the cabinet body 2. The operation panel adopts a touch-type or button-type control interface, providing an intuitive device control method for users. The lighting control button on the panel allows users to manually turn on or off the LED lighting system according to experimental needs, effectively supplementing the automatic lighting control. The up and down control buttons enable the operator to manually adjust the position of the protective door 4, providing a reliable backup control solution in case of failures in the automatic control system or for special operation requirements.

[0049] The exhaust control function is achieved through the corresponding buttons or knobs on the panel. The operator can manually start and stop the exhaust system or adjust the exhaust air volume, thus meeting the different requirements for ventilation intensity under different experimental conditions. The operation panel is also equipped with status indicators, which can display the working status of systems such as lighting, exhaust, and the position of the protective door 4 in real time, enabling the operator to visually monitor the operation of the equipment. The surface of the panel is made of waterproof and corrosion-resistant materials, with good chemical resistance. The sealed design of its button or touch area ensures long-term stable operation in the laboratory chemical environment.

[0050] The operation panel is connected to the control module 12 through a signal line. The control instructions sent by the panel can drive the corresponding actuators after being processed by the control module 12. The manual control mode and the automatic control system are both independent and cooperative. The system operates according to a preset program in the automatic mode, while in the manual mode, the operator can flexibly control various functions according to actual needs. This dual control design not only improves the flexibility and reliability of equipment operation but also ensures that the requirements for safety and convenience in experimental operations can be met under various working conditions.

[0051] The above is only a preferred embodiment of the present utility model and is not intended to limit the utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A fume hood structure, comprising a bottom frame and a cabinet body, wherein the cabinet body is fixed to the upper end of the bottom frame, the cabinet body has an operation area with an opening at the front side, and a protective door capable of sliding up and down is arranged on the front side of the cabinet body, and is characterized in that: A gas hood communicating with the operation area is fixed to the upper end of the cabinet body. A flow guide plate is installed in the operation area. An exhaust passage communicating with the gas hood is formed between the flow guide plate and the cabinet body. A pulley assembly is further provided at the upper end of the cabinet body. The upper end of the protective door is connected with a transmission belt. One end of the transmission belt bypasses the pulley assembly and is connected with a counterweight. The pulley assembly is controlled by a driving motor installed on the cabinet body. A human body induction sensor is also installed on the front side of the cabinet body. A limit switch for contacting the protective door is arranged at the bottom of the cabinet body. The human body induction sensor, the limit switch and the driving motor are respectively electrically connected with a control module. When the human body induction sensor detects that a person has left, the control module controls the driving motor to rotate, driving the protective door to descend to the closed position. When the protective door contacts the limit switch, the control module controls the driving motor to stop working.

2. The structure of a fume hood according to claim 1, wherein: The cabinet body includes a left side plate, a right side plate, a back plate, a top plate and a physical and chemical board tabletop. The left side plate is vertically fixed to the left end of the bottom frame. The right side plate is vertically fixed to the right end of the bottom frame. The back plate is vertically fixed to the rear end of the bottom frame and is fixedly connected to the rear ends of the left side plate and the right side plate. The top plate is horizontally fixed to the upper ends of the left side plate, the right side plate and the back plate. The physical and chemical board tabletop is horizontally fixed to the upper surface of the bottom frame. A left maintenance plate is vertically fixed to the left end of the physical and chemical board tabletop. A first chamber for accommodating pipelines is formed between the left maintenance plate and the left side plate. A right maintenance plate is vertically fixed to the right end of the physical and chemical board tabletop. A second chamber for accommodating pipelines is formed between the right maintenance plate and the right side plate.

3. The structure of a fume hood according to claim 1, wherein: First profiles are vertically arranged at both the left and right ends of the front side of the cabinet body. The left and right side edges of the protective door are respectively in sliding fit with the corresponding first profiles. Second profiles are vertically fixed to both the left and right ends of the rear side of the cabinet body. The second profiles are arranged parallel to the first profiles. The left and right ends of the counterweight are respectively in sliding fit with the corresponding second profiles.

4. The structure of a fume hood according to claim 3, characterized in that: The pulley assembly includes two first pulleys and two second pulleys. A first rotating shaft is rotatably arranged between the two first profiles. The two first pulleys are respectively fixed to both ends of the first rotating shaft. A second rotating shaft is rotatably arranged between the two second profiles. The two second pulleys are respectively fixed to both ends of the second rotating shaft. The upper end of the protective door is connected with two transmission belts. Each transmission belt bypasses the corresponding first pulley and second pulley. The driving motor is in transmission connection with the first rotating shaft or the second rotating shaft.

5. The structure of a fume hood according to claim 4, characterized in that: The counterweight is connected with the two transmission belts through a connecting piece. Rollers are arranged on both sides of the counterweight. The rollers are in rolling fit with the corresponding second profiles.

6. The structure of a fume hood according to claim 2, characterized in that: The bottom opening of the air hood is communicated with the top of the operation area. An exhaust interface is provided at the top of the air hood, and the exhaust interface is used to connect to an external exhaust duct. The deflector includes a vertical deflector and an inclined deflector. The vertical deflector is vertically arranged at the rear side of the operation area, and a plurality of through slots are formed in the vertical deflector. The lower end of the inclined deflector is connected to the upper end of the vertical deflector, and the inclined deflector is inclined downward from front to back. A gap is left between the upper end of the inclined deflector and the top plate.

7. A fume hood structure according to claim 2, characterized in that: An LED lighting lamp is provided at the inner top of the cabinet body. The LED lighting lamp is electrically connected to the control module. When the human body induction sensor detects that a person is approaching, the control module controls the LED lighting lamp to light up. When the protective door descends to the closed position, the control module controls the LED lighting lamp to turn off.

8. A fume hood structure according to claim 1, characterized in that: A movable experimental cabinet is arranged in the bottom frame.

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