An intelligent control system for chemical laboratories

Abstract

The application belongs to the technical field of laboratory equipment, and particularly relates to a chemical laboratory intelligent control system, which comprises a constant-temperature and constant-humidity control module, a variable air volume control module, a negative pressure control module, a toxic gas protection module and a central controller. The central controller is in bidirectional communication connection with the constant-temperature and constant-humidity control module, and is used for regulating the temperature and humidity in the laboratory. The central controller is in bidirectional communication connection with the variable air volume control module, and is used for stabilizing the face air speed of a fume hood. The central controller is in bidirectional communication connection with the negative pressure control module, and is used for maintaining a negative pressure environment and preventing toxic gas overflow. The central controller is in bidirectional communication connection with the toxic gas protection module, and is used for carrying out closed-loop protection according to the type of toxic gas. By using the application, the high-precision requirements of a chemical laboratory on ventilation regulation and toxic gas protection can be met.

Description

Technical Field

[0001] This invention belongs to the field of laboratory equipment technology, and in particular relates to an intelligent control system for chemical laboratories. Background Technology

[0002] With the increasing sophistication and scale of chemical experiments, the types of toxic and hazardous reagents (such as VOCs, chlorine, HF, and benzene compounds) used in laboratories are also increasing. The safety risks and environmental disturbances caused by reagent volatilization and leakage during experiments are becoming increasingly prominent. As core locations for scientific research and teaching, chemical laboratories not only need to meet basic requirements such as stable temperature and humidity, but also need to focus on specific needs such as toxic gas control, localized strong ventilation, and emergency safety safeguards to ensure the health of laboratory personnel, the accuracy of experimental data, and the safe operation of equipment.

[0003] Existing intelligent control technologies for laboratories have established a certain foundation in areas such as temperature and humidity regulation, basic ventilation, and data recording. However, they cannot meet the precision requirements of intelligent control in chemical experiments in terms of ventilation regulation and toxic gas protection. For example, the invention patent with application number 201810099432.0 only activates ventilation or alarms when the gas concentration exceeds a set threshold, failing to consider the "gradual concentration change-rapid diffusion" characteristics of chemical reagent leaks, resulting in a delayed response and easy gas diffusion throughout the room. The invention patent with application number 201910081837.6 is limited to a simple combination of "gas exceeding the standard - ventilation + alarm," without deep interlocking between experimental equipment and environmental safety, and cannot avoid the risks of equipment operation and gas leaks overlapping. The lack of a safety control mechanism during unattended periods means that reagent leaks can easily escalate due to lack of intervention. Furthermore, the emergency response process is not closed-loop, lacking an automated fallback logic of "power cut-off - personnel isolation - precise alerts," relying on manual intervention, which can easily lead to accidents due to untimely handling. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent control system for chemical laboratories, which aims to solve the problem that existing technologies cannot meet the needs of intelligent control in chemical laboratories in terms of ventilation regulation and toxic gas protection.

[0005] To achieve the above objectives, the technical solution provided by this invention is an intelligent control system for a chemical laboratory, comprising a constant temperature and humidity control module, a variable air volume control module, a negative pressure control module, a toxic gas protection module, and a central controller, wherein:

[0006] The central controller is bidirectionally connected to the constant temperature and humidity control module and is used to regulate the temperature and humidity in the laboratory. The central controller is bidirectionally connected to the variable air volume control module to stabilize the air velocity on the fume hood surface. The central controller is bidirectionally connected to the negative pressure control module to maintain a negative pressure environment and prevent the leakage of toxic gases. The central controller is bidirectionally connected to the toxic gas protection module, and is used to carry out closed-loop protection according to the type of toxic gas.

[0007] As an optional embodiment of the present invention, the constant temperature and humidity control module includes a temperature and humidity sensor, a filter differential pressure sensor, a supply / exhaust fan frequency converter, an electric regulating water valve, a rotary dehumidifier unit, and an electric fresh air valve, wherein: The temperature and humidity sensor is electrically connected to the input terminal of the central controller and is used to collect temperature and humidity data of indoor and outdoor air and air conditioning system circulating air. The filter differential pressure sensor is installed at the front and rear ends of the air conditioning unit filter and is electrically connected to the input terminal of the central controller to monitor filter pressure data; The frequency converter of the supply / exhaust fan is electrically connected to the supply fan and exhaust fan of the air conditioning room, and is also connected to the output terminal of the central controller to receive the speed adjustment command of the central controller. The electric regulating water valves are respectively installed on the surface cooler, heater, and humidifier branches of the air conditioning unit, and are connected to the output terminal of the central controller, and are used to adjust the refrigerant and heating medium and the amount of humidifying water according to the instructions of the central controller. The rotary dehumidifier unit is deployed in the air conditioning room and connected to the central controller to deeply reduce the humidity content of the air; The electric fresh air valve is installed near the end of the fresh air inlet duct and is connected to the central controller to regulate the amount of fresh air introduced.

[0008] As an optional embodiment of the present invention, the variable air volume control module includes a face velocity sensor, a fast air valve actuator, a human body sensor, a variable air volume butterfly valve, a variable air volume control unit, and a cabinet door opening sensor, wherein: The face velocity sensor is installed on the operating surface of the fume hood and connected to the variable air volume control unit to detect the face velocity data of the fume hood in real time. The human body sensor is installed above the operating area of ​​the fume hood and connected to the variable air volume control unit to identify the operating status of the experimenter. The fast air valve actuator is deployed near the exhaust duct of the fume hood and connected to the variable air volume control unit to receive opening adjustment commands; The variable air volume butterfly valve is installed on the exhaust branch pipe of the experimental bench and the main exhaust pipe of the whole room, and is connected to the fast air valve driver. The valve opening of the variable air volume butterfly valve is adjusted according to the opening adjustment command. The cabinet door opening sensor is installed on the edge of the fume hood door and connected to the variable air volume control unit to collect cabinet door opening data; The variable air volume control unit is connected to the central controller and transmits cabinet door opening data, fume hood surface wind speed data, and operation status data to the central controller. The central controller stores a variable air volume control algorithm program and generates opening adjustment commands based on the cabinet door opening data, fume hood surface wind speed data, and operation status data.

[0009] As an optional embodiment of the present invention, the negative pressure control module includes a micro differential pressure sensor, a first variable air volume valve, a second variable air volume valve, a flow detector, a negative differential control unit, and a door magnetic sensor, wherein: The micro differential pressure sensor is installed in the partition wall between the laboratory and the corridor and is connected to the negative differential control unit to monitor the actual pressure difference between the laboratory and the external environment in real time. The door magnetic sensor is installed on the door frame of the laboratory room and connected to the negative differential control unit to detect the door's open / closed status. The flow detector is installed in the laboratory supply / exhaust main duct and connected to the negative differential control unit to monitor the total supply / exhaust air volume; The first variable air volume valve is installed at the inlet of the laboratory air supply branch pipe and connected to the negative differential control unit. It is used to receive the adjustment command of the first variable air volume valve and adjust the valve opening of the first variable air volume valve. The second variable air volume valve is installed at the outlet of the laboratory exhaust branch pipe and connected to the negative differential control unit. It is used to receive the adjustment command of the second variable air volume valve and adjust the valve opening of the second variable air volume valve. The negative pressure control unit is connected to the central controller and transmits the actual differential pressure value, the door opening / closing status, and the total supply / exhaust air volume to the central controller. The central controller stores a negative pressure control algorithm program and generates a first variable air volume valve adjustment command and a second variable air volume valve adjustment command based on the actual differential pressure value, the door opening / closing status, and the total supply / exhaust air volume.

[0010] As an optional embodiment of the present invention, the toxic gas protection module includes a composite gas sensor, an aerosol purification device, a reagent cabinet miniature exhaust pump, an emergency exhaust channel solenoid valve, and an alarm module, wherein: The composite gas sensor is deployed in reagent cabinets, fume hoods, laboratory zones, and the main return air in the room, and is connected to the central controller to detect the concentration of harmful gases in real time and upload gas characteristic signals. The central controller stores a toxic gas protection algorithm program, which generates protection commands and alarm information based on the concentration of harmful gases and gas characteristic signals. The aerosol purification device is installed at the end of the main exhaust duct of the whole room and the exhaust branch duct of the fume hood, and is connected to the central controller to receive the protection command of the central controller and start the purification function. The reagent cabinet's miniature exhaust pump is installed on the top of the reagent cabinet and connected to the central controller. It is used to receive protection commands from the central controller and perform local exhaust ventilation. The emergency exhaust channel solenoid valve is installed on the spare branch of the main exhaust pipe of the whole room and is connected to the central controller. It is used to exhaust harmful gases in the event of a gas leak crisis. The alarm module is connected to the central controller and is used to trigger and push corresponding alarm information according to the warning level, emergency level, and crisis level when the gas concentration exceeds the limit.

[0011] As an optional embodiment of the present invention, the central controller also stores a constant temperature and humidity control algorithm program, including the following steps: Calculate the indoor and outdoor enthalpy values ​​based on the temperature and humidity data; The priority of fresh air is determined based on the difference between the indoor and outdoor enthalpy values, and control instructions for the electric fresh air valve are generated. Calculate the temperature deviation value and humidity deviation value based on the temperature and humidity data; The opening command of the electric regulating water valve, the speed regulation command of the supply / exhaust fan inverter, and the humidity control command of the rotary dehumidifier are generated based on the temperature deviation value and the humidity deviation value. The speed adjustment command of the supply / exhaust fan inverter and the control command of the electric fresh air valve are compensated based on the filter pressure data to obtain the compensated speed adjustment command of the supply / exhaust fan inverter and the compensated control command of the electric fresh air valve.

[0012] As an optional embodiment of the present invention, the variable air volume control algorithm program includes the following steps: The target wind speed is determined based on the operational status data and the cabinet door opening data. Calculate the difference between the surface wind speed data of the fume hood and the target wind speed; Based on the comparison between the difference between the fume hood surface wind speed data and the target wind speed and a preset threshold, an opening adjustment command is generated.

[0013] As an optional embodiment of the present invention, the negative pressure control algorithm program includes the following steps: The compensation coefficient is determined based on the door's open / closed state. The preset pressure difference value is compensated based on the compensation coefficient to obtain the compensated pressure difference value; Based on the comparison between the compensated differential pressure value and the actual differential pressure value, a first variable air volume valve adjustment command and a second variable air volume valve adjustment command are generated. Calculate the difference between the total supply air volume and the total exhaust air volume, and modify the first variable air volume valve adjustment command and the second variable air volume valve adjustment command based on the difference to obtain the modified first variable air volume valve adjustment command and the second variable air volume valve adjustment command.

[0014] As an optional embodiment of the present invention, the gas protection algorithm program includes the following steps: Concentration change rate curves were constructed based on the concentration of harmful gases. The concentration change rate curve is classified and early warning is issued according to the preset concentration change value to obtain different levels of early warning response; Protection commands and alarm information are generated based on gas characteristic signals and early warning responses.

[0015] The above-mentioned technical solutions in the intelligent control system for a chemical laboratory provided by the embodiments of the present invention have at least one of the following technical effects: This application provides an intelligent control system for a chemical laboratory. Through enthalpy calculation logic based on temperature and humidity data, combined with the opening control of an electric fresh air valve, it maximizes the utilization of fresh air during transitional seasons, reduces the cooling / heating load of the air conditioning system, and achieves energy-saving goals. Through a constant temperature and humidity control algorithm, it links an electric regulating water valve, supply / exhaust fan inverters, and a rotary dehumidifier unit to precisely control temperature and humidity fluctuations in the laboratory, meeting the stable temperature and humidity requirements of chemical experiments. Through the compensation effect of filter differential pressure data, it promptly corrects fan speed and fresh air valve opening, offsetting the airflow reduction and heat exchange efficiency decrease caused by filter blockage, avoiding lag in temperature and humidity regulation, and ensuring long-term stable control accuracy. Through multi-data fusion from human body sensors, cabinet door opening sensors, and face velocity sensors, combined with a target wind speed matching algorithm, it achieves adaptive adjustment of fume hood wind speed, adapting to different scenarios such as "no operation - routine experiments - reagent transfer". Through a variable air volume control algorithm, it links a rapid air valve driver and a variable air volume butterfly valve to ensure stable fume hood face velocity, preventing the escape of harmful gases and avoiding energy waste caused by excessive exhaust. The target negative pressure value is corrected by compensating for the door status using a door magnetic sensor, and coordinated with the first / second variable air volume valves to maintain stable negative pressure in the laboratory and prevent the spread of toxic gases. Supply / exhaust air volume data collected by a flow detector serves as the basis for verifying and correcting negative pressure regulation, effectively avoiding "false negative pressure" or excessive negative pressure. Simultaneously, when multiple fume hoods are operating simultaneously, it anticipates load changes in advance, ensuring negative pressure stability and preventing system overload. Composite gas sensors deployed in reagent cabinets, fume hoods, laboratory zones, and the main return air outlet provide comprehensive, high-precision monitoring of harmful gas concentrations, accurately distinguishing between different gas types such as acidic, organic, and toxic gases. A three-level early warning response mechanism based on concentration change rate curves triggers progressive protective actions of "local exhaust - enhanced exhaust - emergency interlock," linking aerosol purification devices, emergency exhaust channel solenoid valves, and alarm modules to form a closed-loop protection system of "detection - identification - response - alarm," minimizing the risk of toxic gas leakage. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of an intelligent control system for a chemical laboratory according to the present invention.

[0018] Figure 2This is a flowchart of the constant temperature and humidity control algorithm for an intelligent control system for a chemical laboratory according to the present invention.

[0019] Figure 3 This is a flowchart of the variable air volume control algorithm for an intelligent control system for a chemical laboratory according to the present invention.

[0020] Figure 4 This is a flowchart of the negative pressure control algorithm for an intelligent control system for a chemical laboratory according to the present invention.

[0021] Figure 5 This is a flowchart of the toxic gas protection algorithm for an intelligent control system for a chemical laboratory according to the present invention. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain embodiments of the present invention, and should not be construed as limiting the present invention.

[0023] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0026] In specific embodiments of the present invention, such as Figure 1 As shown, a chemical laboratory intelligent control system is provided, including a constant temperature and humidity control module, a variable air volume control module, a negative pressure control module, a toxic gas protection module, and a central controller, wherein: The constant temperature and humidity control module establishes a bidirectional communication connection with the central controller through the standard MODBUS RTU protocol. On the one hand, the central controller receives the temperature and humidity data and filter pressure data of the indoor and outdoor air and the air conditioning system circulating air collected by the constant temperature and humidity control module. On the other hand, the central controller stores the constant temperature and humidity control algorithm program and outputs the corresponding drive control commands to the hardware unit of the constant temperature and humidity control module according to the temperature and humidity data and filter pressure data of the indoor and outdoor air and the air conditioning system circulating air.

[0027] The variable air volume (VAV) control module establishes a two-way communication connection with the central controller through the standard MODBUS RTU protocol. On the one hand, the central controller receives cabinet door opening data, fume hood surface wind speed data, and operation status data collected by the VAV control module. On the other hand, the central controller stores a VAV control algorithm program and outputs opening adjustment commands to the VAV control module based on the cabinet door opening data, fume hood surface wind speed data, and operation status data.

[0028] The negative pressure control module establishes a bidirectional communication connection with the central controller through the standard MODBUS RTU protocol. On the one hand, the central controller receives differential pressure data, door opening / closing status data, and total supply / exhaust air volume data collected by the negative pressure control module. On the other hand, the central controller stores a negative pressure control algorithm program, which outputs the first variable air volume valve adjustment command and the second variable air volume valve adjustment command to the negative pressure control module based on the differential pressure data, door opening / closing status data, and total supply / exhaust air volume data.

[0029] The toxic gas protection module establishes a two-way communication connection with the central controller through the standard MODBUS RTU protocol. On the one hand, the central controller receives the harmful gas concentration and gas characteristic signals collected by the toxic gas protection module. On the other hand, the central controller stores the toxic gas protection algorithm program and outputs protection commands and alarm information to the toxic gas protection module based on the harmful gas concentration and gas characteristic signals.

[0030] In a specific embodiment of the present invention, the preferred model of the central controller is a Siemens S7-1500 PLC controller, which stores constant temperature and humidity control algorithm programs, variable air volume control algorithm programs, negative pressure control algorithm programs, and toxic gas protection algorithm programs. The central controller is electrically connected to an industrial touch screen, which is deployed in the laboratory control room to display real-time data and alarm information received by the central controller.

[0031] Specifically, the constant temperature and humidity control module includes a temperature and humidity sensor, a filter differential pressure sensor, a supply / exhaust fan frequency converter, an electric regulating water valve, a rotary dehumidifier unit, and an electric fresh air valve, among which: The temperature and humidity sensor in a specific embodiment of the present invention is preferably a wall-mounted sensor with an accuracy of ±0.3℃ and ±2% RH, which is deployed in the laboratory room, air conditioning return air duct, air supply duct and outdoor fresh air inlet. The temperature and humidity sensor is electrically connected to the input terminal of the central controller and is used to collect temperature and humidity data of indoor and outdoor air and air conditioning system circulating air.

[0032] In a specific embodiment of the present invention, the filter differential pressure sensor is installed at the front and rear ends of the filter of the air conditioning unit. The filter differential pressure sensor is electrically connected to the input terminal of the central controller to monitor and collect filter pressure data in real time.

[0033] In a specific embodiment of the present invention, the power of the supply fan frequency converter is preferably 15kW. The supply fan frequency converter is electrically connected to the air conditioning room supply fan to drive the supply fan to rotate. The supply fan frequency converter is connected to the central controller DO module via a relay to receive speed adjustment commands, and the speed adjustment range is preferably 5-50Hz. In a specific embodiment of the present invention, the power of the exhaust fan frequency converter is preferably 18kW. The exhaust fan frequency converter is electrically connected to the air conditioning room exhaust fan to drive the exhaust fan to rotate. The exhaust fan frequency converter is connected to the central controller DO module via a relay to receive speed adjustment commands, and the speed adjustment range is preferably 5-50Hz.

[0034] In a specific embodiment of the present invention, the electric regulating water valve is preferably a proportional-integral type electric regulating valve, which is installed on the surface cooler, heater, and humidifier branches of the air conditioning unit and connected to the output terminal of the central controller, for adjusting the amount of refrigerant and heating medium and humidifying water according to the instructions of the central controller.

[0035] In a specific embodiment of the present invention, the rotary dehumidifier unit is deployed in the air conditioning room and connected to the central controller via a communication line to deeply reduce the humidity content of the air.

[0036] In a specific embodiment of the present invention, the electric fresh air valve is installed near the end of the fresh air inlet duct (close to the outdoor air intake) and connected to the central controller to regulate the amount of fresh air introduced.

[0037] After receiving temperature and humidity data and filter pressure data from the indoor and outdoor air and the circulating air of the air conditioning system, the central controller runs the constant temperature and humidity control algorithm program, including the following steps: The indoor and outdoor enthalpy values ​​are calculated based on the temperature and humidity data of indoor and outdoor environments and the circulating air of the air conditioning system. The calculation expressions for the indoor and outdoor enthalpy values ​​are as follows:

[0038]

[0039]

[0040] in, Indicates the indoor enthalpy value. Indicates indoor temperature value (letter) (For interior use only) This indicates the humidity level of the indoor air. This indicates the indoor humidity level. Indicates the partial pressure of saturated water vapor. This indicates the actual partial pressure of water vapor in the room. This indicates atmospheric pressure.

[0041]

[0042]

[0043]

[0044] in, Indicates the outdoor enthalpy value. Indicates outdoor temperature value (letter) (For outdoor use only) Indicates the humidity content of outdoor air. This indicates the outdoor humidity level. This indicates the actual partial pressure of water vapor outdoors.

[0045] The priority of fresh air is determined based on the difference between indoor and outdoor enthalpy values, and control instructions for electric fresh air valves are generated. Specifically, when the outdoor enthalpy is less than the difference between the indoor enthalpy and the preset enthalpy, that is... , The preset enthalpy value indicates that introducing fresh outdoor air at this time helps the constant temperature and humidity control module save energy. The central controller generates a control command to increase the opening of the electric fresh air valve, and at the same time generates a command to drive the frequency converter of the air supply fan to increase the speed, so as to introduce fresh outdoor air to save energy.

[0046] When the outdoor enthalpy is greater than the sum of the indoor enthalpy and the preset enthalpy, that is... This indicates that introducing fresh outdoor air at this time is not conducive to energy saving of the constant temperature and humidity control module, and the central controller generates a control command to reduce the opening of the electric fresh air valve.

[0047] Calculate the temperature deviation value and humidity deviation value based on the temperature and humidity data; Specifically, the difference between the collected indoor temperature value and the preset indoor temperature value is calculated to obtain the temperature deviation value. In this specific embodiment of the invention, the preset indoor temperature value is 25℃. The target supply air temperature is determined based on the temperature deviation value. When the temperature deviation value is greater than 0.5℃, the target supply air temperature is 20℃; when the temperature deviation value is less than -0.5℃, the target supply air temperature is 30℃; when the temperature deviation value is between -0.5℃ and 0.5℃, the target supply air temperature is linearly adjusted between 20℃ and 30℃. The collected supply air temperature value is compared with the target supply air temperature to obtain the supply air temperature deviation value.

[0048] The difference between the collected indoor humidity value and the preset indoor humidity value is calculated to obtain the humidity deviation value. In this specific embodiment of the invention, the preset indoor humidity value is 50%. The target supply air humidity is determined based on the humidity deviation value. When the humidity deviation value is greater than 3%, the target supply air humidity is 40%; when the humidity deviation value is less than -3%, the target supply air humidity is 60%; when the humidity deviation value is between -3% and 3%, the target supply air temperature is linearly adjusted between 40% and 60%. The collected supply air humidity value is compared with the target supply air humidity to obtain the supply air humidity deviation value.

[0049] The opening command of the electric regulating water valve, the speed adjustment command of the supply / exhaust fan inverter, and the humidity control command of the rotary dehumidifier are generated based on the temperature deviation value and the humidity deviation value.

[0050] Specifically, when the temperature deviation exceeds 0.5℃ (i.e., indoor overheating), the central controller outputs a command to increase the opening of the electric regulating water valve at the surface cooler, with the opening increment as follows:

[0051] in, Indicates the increment of opening; This indicates the deviation value of the supply air humidity; This represents the proportional coefficient in the feedback control parameters; This represents the integral coefficient in the feedback control parameters; This represents the derivative coefficient in the feedback control parameters; in a specific embodiment of the present invention .

[0052] At the same time, the central controller outputs a speed increase command to the blower inverter to accelerate the diffusion of cold air. The speed increase is as follows:

[0053] in, This indicates the increase in the speed of the blower inverter during cooling. This indicates the temperature deviation value.

[0054] When the temperature deviation is less than -0.5℃ (i.e., the room is too cold): the central controller outputs a command to increase the opening of the electric regulating water valve at the heater, and the calculation expression for the opening increment is the same as above. Consistent, but the coefficients are adjusted to Meanwhile, the central controller maintains the fan speed at the current value to prevent excessive temperature rise.

[0055] Specifically, when the humidity deviation exceeds 3% (i.e., the indoor humidity is too high), the central controller outputs a command to increase the opening of the electric regulating water valve at the surface cooler, a start command for the rotary dehumidifier unit, and a command to increase the speed of the blower inverter to ensure dehumidification effect. The speed increase is as follows:

[0056] in, This indicates the increase in the speed of the blower inverter during dehumidification. This indicates the humidity deviation value.

[0057] When the humidity deviation is less than -3% (i.e., the indoor air is too dry), the central controller outputs a command to increase the opening of the electric regulating water valve at the humidifier. The calculation expression for the opening increment is the same as described above. Consistent, but the coefficients are adjusted to Meanwhile, the central controller controls the fan speed to maintain the current value, so as to evenly diffuse the moisture.

[0058] The speed adjustment command of the supply / exhaust fan inverter and the control command of the electric fresh air valve are compensated based on the filter pressure data to obtain the compensated speed adjustment command of the supply / exhaust fan inverter and the compensated control command of the electric fresh air valve.

[0059] Specifically, the filter pressure data is divided based on the differential pressure threshold. When the filter pressure is less than 150 Pa, the filter is in normal working condition and no compensation is required. When the filter pressure is greater than 150 Pa and less than 200 Pa, the filter is in a slightly clogged state. When the filter pressure is greater than 200 Pa, the filter is in a moderately clogged state.

[0060] When the filter is slightly clogged, the central controller outputs a speed compensation command for the blower inverter to compensate for the airflow reduction. The compensation amount is 10Hz increase in speed for every 50Pa increase in filter pressure compared to 150Pa. Simultaneously, the central controller outputs a command to reduce the opening of the electric fresh air valve, with a reduction of 10% for every 50Pa increase in filter pressure compared to 150Pa.

[0061] When the filter is moderately clogged, the central controller outputs a control command to forcibly limit the opening of the electric fresh air valve to 20%, while simultaneously increasing the speed of the blower inverter to the maximum. At the same time, the industrial touch screen and mobile terminal push "filter maintenance reminder". If the blower air volume decreases by more than 30% (calculated by the blower speed and the total air volume fed back), the central controller outputs a control command to shut down the rotary dehumidifier unit, prioritizing the protection of core temperature and humidity indicators.

[0062] Specifically, the variable air volume (VAV) control module includes a face velocity sensor, a fast-acting damper actuator, a human body sensor, a VAV butterfly valve, a VAV control unit, and a cabinet door opening sensor, among which: In a specific embodiment of the present invention, the face velocity sensor is installed on the operating surface of each fume hood (10cm from the door). The face velocity sensor is connected to the variable air volume control unit via a shielded cable to detect the face velocity data of the fume hood in real time.

[0063] In a specific embodiment of the present invention, the human body sensor is preferably an infrared sensor. The human body sensor is installed above the operating area of ​​the fume hood (0.5m from the table surface), and its sensing distance is 0-3m. The human body sensor is connected to the variable air volume control unit and is used to identify the operating status of the experimental personnel.

[0064] In a specific embodiment of the present invention, the rapid air valve actuator is deployed near the exhaust duct of each fume hood. The rapid air valve actuator is connected to the variable air volume control unit and is used to receive opening adjustment commands.

[0065] In a specific embodiment of the present invention, the variable air volume butterfly valve is installed on the exhaust branch pipe of each experimental bench and the main exhaust pipe of the whole room. The variable air volume butterfly valve is connected to the fast air valve driver. The valve opening of the variable air volume butterfly valve is linearly corresponding to the output shaft rotation angle of the fast air valve driver. When the output shaft rotation angle is 0°, the variable air volume butterfly valve is completely closed. When the output shaft rotation angle is 90°, the variable air volume butterfly valve is fully opened. The fast air valve driver adjusts the angle of the output shaft rotation according to the opening adjustment command to adjust the valve opening of the variable air volume butterfly valve.

[0066] In a specific embodiment of the present invention, the cabinet door opening sensor is preferably a pull-wire displacement sensor. The cabinet door opening sensor is installed on the edge of the fume hood door and connected to the variable air volume control unit to collect cabinet door opening data.

[0067] In a specific embodiment of the present invention, the variable air volume control unit is preferably an embedded controller. The variable air volume control unit is deployed in the control cabinet next to the fume hood and connected to the central controller. It is responsible for collecting and uploading the sensor data of this module, and at the same time receiving instructions from the central controller to drive the execution components.

[0068] After receiving the cabinet door opening data, fume hood surface air velocity data, and operation status data transmitted by the variable air volume control unit, the central controller runs the variable air volume control algorithm program, including the following steps: The target wind speed is determined based on the operational status data and the cabinet door opening data. Specifically, the target wind speed is determined based on a two-dimensional matrix of the operating status and cabinet door opening. The two-dimensional matrix table is as follows: Table 1. Two-dimensional matrix table of operating status and cabinet door opening.

[0069] Calculate the difference between the surface wind speed data of the fume hood and the target wind speed; Based on the comparison between the difference between the fume hood surface wind speed data and the target wind speed and a preset threshold, an opening adjustment command is generated.

[0070] Specifically, when the difference between the fume hood surface velocity data and the target velocity is greater than 0.05 m / s, the central controller generates an adjustment command to reduce the opening of the variable air volume butterfly valve; when the difference between the fume hood surface velocity data and the target velocity is less than -0.05 m / s, the central controller generates an adjustment command to increase the opening of the variable air volume butterfly valve.

[0071] Specifically, the negative pressure control module includes a micro differential pressure sensor, a first variable air volume valve, a second variable air volume valve, a flow detector, a negative pressure control unit, and a door magnetic sensor, wherein: In a specific embodiment of the present invention, a micro differential pressure sensor is installed in the partition wall between the laboratory and the corridor. The micro differential pressure sensor is connected to a negative pressure control unit and is used to monitor the pressure difference between the laboratory and the corridor.

[0072] In a specific embodiment of the present invention, the door magnetic sensor is preferably a magnetic induction switch. The door magnetic sensor is installed on the door frame of the laboratory room and connected to the negative pressure control unit to detect the door's open / closed status.

[0073] In a specific embodiment of the present invention, the first variable air volume valve is preferably an electrically adjustable valve with a diameter of DN180. The first variable air volume valve is installed at the inlet of the laboratory air supply branch pipe and is connected to the negative pressure control unit for adjusting the air supply volume.

[0074] In a specific embodiment of the present invention, the second variable air volume valve is preferably an electrically adjustable valve with a diameter of DN200. The second variable air volume valve is installed at the outlet of the laboratory exhaust branch pipe and connected to the negative pressure control unit for adjusting the exhaust air volume.

[0075] In a specific embodiment of the present invention, the flow detector is preferably a vortex flow meter. The flow detector is installed on the laboratory supply / exhaust main duct and connected to the negative pressure control unit to collect total supply / exhaust air volume data.

[0076] In a specific embodiment of the present invention, the negative pressure control unit is preferably an embedded controller. The negative pressure control unit is deployed in the control room and connected to the central controller, and is responsible for data acquisition and instruction execution of this module.

[0077] After receiving the actual differential pressure value, door open / close status, and total supply / exhaust air volume data transmitted by the negative pressure control unit, the central controller runs the negative pressure control algorithm program, including the following steps: The compensation coefficient is determined based on the door's open / closed state. Specifically, opening the door can cause air leakage and affect the stability of negative pressure. In a specific embodiment of the present invention, the target negative pressure is corrected by a compensation coefficient. When the door is closed, the compensation coefficient is 1; when the door is open, the compensation coefficient is 1.25.

[0078] The preset pressure difference value is compensated based on the compensation coefficient to obtain the compensated pressure difference value; Specifically, in a specific embodiment of the present invention, the preset differential pressure value is -8Pa. When the door is closed, the compensation differential pressure value is -8Pa; when the door is open, the compensation differential pressure value is -10Pa.

[0079] Based on the comparison between the compensated differential pressure value and the actual differential pressure value, a first variable air volume valve adjustment command and a second variable air volume valve adjustment command are generated. Specifically, the difference between the actual pressure difference and the compensated pressure difference is calculated. If the difference is greater than a first preset difference (preferably 2 Pa in this specific embodiment), it indicates insufficient negative pressure. The central controller then generates a second variable air volume (VAV) valve adjustment command to increase the opening of the second VAV valve (exhaust side) and a first VAV valve adjustment command to decrease the opening of the first VAV valve (supply side). If the difference is less than a second preset difference (preferably -2 Pa in this specific embodiment), it indicates excessive negative pressure. The central controller then generates a second VAV valve adjustment command to decrease the opening of the second VAV valve (exhaust side) and a first VAV valve adjustment command to increase the opening of the first VAV valve (supply side).

[0080] Calculate the difference between the total supply air volume and the total exhaust air volume, and modify the first variable air volume valve adjustment command and the second variable air volume valve adjustment command based on the difference to obtain the modified first variable air volume valve adjustment command and the second variable air volume valve adjustment command.

[0081] Specifically, the correction logic is as follows: If the difference between the actual differential pressure value and the compensated differential pressure value is greater than the first preset difference, and the difference between the total supply air volume and the total exhaust air volume is greater than the first difference (the first difference in the specific embodiment of the present invention is preferably 200 m³ / h), that is, the difference between the total supply air volume and the total exhaust air volume is too large, the second variable air volume valve adjustment command is not changed, and a corrected second variable air volume valve adjustment command is obtained. Based on the first variable air volume valve adjustment command, a command to finely adjust and reduce the opening of the first variable air volume valve is generated, and a corrected first variable air volume valve adjustment command is obtained.

[0082] If the difference between the actual differential pressure value and the compensated differential pressure value is less than the second preset difference, and the difference between the total supply air volume and the total exhaust air volume is less than the second difference (the first difference in the specific embodiment of the present invention is preferably 50 m³ / h), that is, the difference between the total supply air volume and the total exhaust air volume is too small, the second variable air volume valve adjustment command is not changed, and the corrected second variable air volume valve adjustment command is obtained. Based on the first variable air volume valve adjustment command, an instruction to finely adjust and increase the opening of the first variable air volume valve is generated, and the corrected first variable air volume valve adjustment command is obtained.

[0083] Specifically, the toxic gas protection module includes a composite gas sensor, an aerosol purification device, a reagent cabinet miniature exhaust pump, an emergency exhaust channel solenoid valve, and an alarm module, among which: The composite gas sensor in a specific embodiment of the present invention is preferably an electrochemical PID dual-backup sensor, which can detect gas types including VOC, HF, HCl, and chlorine. The composite gas sensor is deployed in reagent cabinets, fume hoods, laboratory zones, and the main return air in the whole room, and is connected to the central controller via an RS485 bus for real-time detection of harmful gas concentrations and uploading gas characteristic signals (organic gases or acidic gases).

[0084] The aerosol purification device in a specific embodiment of the present invention is preferably a composite filter purification device compatible with activated carbon and impregnated potassium hydroxide. It has a built-in activated carbon filter (for treating organic gases) and an impregnated potassium hydroxide filter (for treating acidic gases), and switches the filter via a solenoid valve. The aerosol purification device is installed at the end of the main exhaust duct of the whole room and the exhaust branch duct of each fume hood, and is connected to a central controller to receive protection commands from the central controller and start the purification function.

[0085] In a specific embodiment of the present invention, the reagent cabinet miniature exhaust pump is preferably a silent centrifugal exhaust pump. The reagent cabinet miniature exhaust pump is installed on the top of the reagent cabinet (with an external exhaust duct) and connected to the central controller to receive protection commands from the central controller and perform local exhaust.

[0086] In a specific embodiment of the present invention, the emergency exhaust channel solenoid valve is installed on the spare branch of the main exhaust pipe of the whole room and connected to the central controller, and is used to discharge harmful gases in the event of a gas leak crisis.

[0087] The alarm module in a specific embodiment of the present invention includes a laboratory indoor audible and visual alarm, a duty room alarm host, and a mobile APP push unit. The alarm module is communicatively connected to the central controller and is used to trigger and push corresponding alarm information according to the warning level, emergency level, and crisis level when the gas concentration exceeds the limit.

[0088] After receiving the hazardous gas concentration and gas characteristic signals, the central controller operates based on the hazardous gas concentration and gas characteristic signals, including the following steps: Concentration change rate curves were constructed based on the concentration of harmful gases. Specifically, the concentration change rate is calculated using the sliding window method. In this specific embodiment of the invention, the window size is 5 seconds, and the expression for calculating the concentration change rate is as follows:

[0089] in, Indicates the rate of change of concentration; This represents the concentration difference within a single time window; Indicates the duration of the time window; Indicates the current time point (specifically...) The gas concentration at that time; This indicates the gas concentration 5 seconds ago.

[0090] The concentration change rate curve is classified and early warning is issued according to the preset concentration change value to obtain different levels of early warning response; Specifically, based on the concentration change rate curve, three warning levels are defined: warning level, emergency level, and crisis level. In a specific embodiment of this invention, tiered warning thresholds are set for these three warning levels. The threshold for the warning level is... ,and The threshold for emergency response is... ,and The threshold for emergency response is... ,and .

[0091] Protection commands and alarm information are generated based on gas characteristic signals and early warning responses.

[0092] Specifically, when in the warning level, the central controller outputs a control signal to start the micro exhaust pump of the reagent cabinet in the corresponding leak area. Based on the gas characteristic signal (organic gas or acidic gas), the central controller outputs a control signal to the solenoid valve of the aerosol purification device to switch the filter element, thereby achieving targeted purification of harmful gases. At the same time, the central controller pushes a "potential leak, check recommended" prompt to the alarm module.

[0093] When in emergency mode, the central controller outputs a control signal to increase the opening of the variable air volume butterfly valve of the fume hood in the corresponding leak area, and increases the speed of the exhaust fan inverter. At the same time, the central controller sends an intermittent alarm command to the audible and visual alarm of the alarm module, and pushes the alarm information to the administrator.

[0094] In a crisis-level situation, the central controller outputs control commands to open the emergency exhaust channel solenoid valve, activate the backup exhaust branch, drive the audible and visual alarm to continuously sound, and push alarm information to the administrator and safety manager. At the same time, the constant temperature and humidity module suspends temperature and humidity adjustment to prioritize exhaust ventilation.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An intelligent control system for a chemical laboratory, characterized in that, It includes a constant temperature and humidity control module, a variable air volume control module, a negative pressure control module, a toxic gas protection module, and a central controller, among which: The central controller is bidirectionally connected to the constant temperature and humidity control module and is used to regulate the temperature and humidity in the laboratory. The central controller is bidirectionally connected to the variable air volume control module to stabilize the air velocity on the fume hood surface. The central controller is bidirectionally connected to the negative pressure control module to maintain a negative pressure environment and prevent the leakage of toxic gases. The central controller is bidirectionally connected to the toxic gas protection module, and is used to carry out closed-loop protection according to the type of toxic gas.

2. The intelligent control system for a chemical laboratory according to claim 1, characterized in that, The constant temperature and humidity control module includes a temperature and humidity sensor, a filter differential pressure sensor, a supply / exhaust fan frequency converter, an electric regulating water valve, a rotary dehumidifier unit, and an electric fresh air valve, wherein: The temperature and humidity sensor is electrically connected to the input terminal of the central controller and is used to collect temperature and humidity data of indoor and outdoor air and air conditioning system circulating air. The filter differential pressure sensor is installed at the front and rear ends of the air conditioning unit filter and is electrically connected to the input terminal of the central controller to monitor filter pressure data; The frequency converter of the supply / exhaust fan is electrically connected to the supply fan and exhaust fan of the air conditioning room, and is also connected to the output terminal of the central controller to receive the speed adjustment command of the central controller. The electric regulating water valves are respectively installed on the surface cooler, heater, and humidifier branches of the air conditioning unit, and are connected to the output terminal of the central controller, and are used to adjust the refrigerant and heating medium and the amount of humidifying water according to the instructions of the central controller. The rotary dehumidifier unit is deployed in the air conditioning room and connected to the central controller to deeply reduce the humidity content of the air; The electric fresh air valve is installed near the end of the fresh air inlet duct and is connected to the central controller to regulate the amount of fresh air introduced.

3. The intelligent control system for a chemical laboratory according to claim 1, characterized in that, The variable air volume (VAV) control module includes a face velocity sensor, a fast-acting damper actuator, a human body sensor, a VAV butterfly valve, a VAV control unit, and a cabinet door opening sensor, wherein: The face velocity sensor is installed on the operating surface of the fume hood and connected to the variable air volume control unit to detect the face velocity data of the fume hood in real time. The human body sensor is installed above the operating area of ​​the fume hood and connected to the variable air volume control unit to identify the operating status of the experimenter. The fast air valve actuator is deployed near the exhaust duct of the fume hood and connected to the variable air volume control unit to receive opening adjustment commands; The variable air volume butterfly valve is installed on the exhaust branch pipe of the experimental bench and the main exhaust pipe of the whole room, and is connected to the fast air valve driver. The valve opening of the variable air volume butterfly valve is adjusted according to the opening adjustment command. The cabinet door opening sensor is installed on the edge of the fume hood door and connected to the variable air volume control unit to collect cabinet door opening data; The variable air volume control unit is connected to the central controller and transmits cabinet door opening data, fume hood surface wind speed data, and operation status data to the central controller. The central controller stores a variable air volume control algorithm program and generates opening adjustment commands based on the cabinet door opening data, fume hood surface wind speed data, and operation status data.

4. The intelligent control system for a chemical laboratory according to claim 1, characterized in that, The negative pressure control module includes a micro differential pressure sensor, a first variable air volume valve, a second variable air volume valve, a flow detector, a negative differential pressure control unit, and a door magnetic sensor, wherein: The micro differential pressure sensor is installed in the partition wall between the laboratory and the corridor and is connected to the negative differential control unit to monitor the actual pressure difference between the laboratory and the external environment in real time. The door magnetic sensor is installed on the door frame of the laboratory room and connected to the negative differential control unit to detect the door's open / closed status. The flow detector is installed in the laboratory supply / exhaust main duct and connected to the negative differential control unit to monitor the total supply / exhaust air volume; The first variable air volume valve is installed at the inlet of the laboratory air supply branch pipe and connected to the negative differential control unit. It is used to receive the adjustment command of the first variable air volume valve and adjust the valve opening of the first variable air volume valve. The second variable air volume valve is installed at the outlet of the laboratory exhaust branch pipe and connected to the negative differential control unit. It is used to receive the adjustment command of the second variable air volume valve and adjust the valve opening of the second variable air volume valve. The negative pressure control unit is connected to the central controller and transmits the actual differential pressure value, the door opening / closing status, and the total supply / exhaust air volume to the central controller. The central controller stores a negative pressure control algorithm program and generates a first variable air volume valve adjustment command and a second variable air volume valve adjustment command based on the actual differential pressure value, the door opening / closing status, and the total supply / exhaust air volume.

5. The intelligent control system for a chemical laboratory according to claim 1, characterized in that, The toxic gas protection module includes a composite gas sensor, an aerosol purification device, a reagent cabinet miniature exhaust pump, an emergency exhaust channel solenoid valve, and an alarm module, wherein: The composite gas sensor is deployed in reagent cabinets, fume hoods, laboratory zones, and the main return air in the room, and is connected to the central controller to detect the concentration of harmful gases in real time and upload gas characteristic signals. The central controller stores a toxic gas protection algorithm program, which generates protection commands and alarm information based on the concentration of harmful gases and gas characteristic signals. The aerosol purification device is installed at the end of the main exhaust duct of the whole room and the exhaust branch duct of the fume hood, and is connected to the central controller to receive the protection command of the central controller and start the purification function. The reagent cabinet's miniature exhaust pump is installed on the top of the reagent cabinet and connected to the central controller. It is used to receive protection commands from the central controller and perform local exhaust ventilation. The emergency exhaust channel solenoid valve is installed on the spare branch of the main exhaust pipe of the whole room and is connected to the central controller. It is used to exhaust harmful gases in the event of a gas leak crisis. The alarm module is connected to the central controller and is used to trigger and push corresponding alarm information according to the warning level, emergency level, and crisis level when the gas concentration exceeds the limit.

6. The intelligent control system for a chemical laboratory according to claim 2, characterized in that, The central controller also stores a constant temperature and humidity control algorithm program, including the following steps: Calculate the indoor and outdoor enthalpy values ​​based on the temperature and humidity data; The priority of fresh air is determined based on the difference between the indoor and outdoor enthalpy values, and control instructions for the electric fresh air valve are generated. Calculate the temperature deviation value and humidity deviation value based on the temperature and humidity data; The opening command of the electric regulating water valve, the speed regulation command of the supply / exhaust fan inverter, and the humidity control command of the rotary dehumidifier are generated based on the temperature deviation value and the humidity deviation value. The speed adjustment command of the supply / exhaust fan inverter and the control command of the electric fresh air valve are compensated based on the filter pressure data to obtain the compensated speed adjustment command of the supply / exhaust fan inverter and the compensated control command of the electric fresh air valve.

7. The intelligent control system for a chemical laboratory according to claim 3, characterized in that, The variable air volume control algorithm program includes the following steps: The target wind speed is determined based on the operational status data and the cabinet door opening data. Calculate the difference between the surface wind speed data of the fume hood and the target wind speed; Based on the comparison between the difference between the fume hood surface wind speed data and the target wind speed and a preset threshold, an opening adjustment command is generated.

8. The intelligent control system for a chemical laboratory according to claim 4, characterized in that, The negative pressure control algorithm program includes the following steps: The compensation coefficient is determined based on the door's open / closed state. The preset pressure difference value is compensated based on the compensation coefficient to obtain the compensated pressure difference value; Based on the comparison between the compensated differential pressure value and the actual differential pressure value, a first variable air volume valve adjustment command and a second variable air volume valve adjustment command are generated. Calculate the difference between the total supply air volume and the total exhaust air volume, and modify the first variable air volume valve adjustment command and the second variable air volume valve adjustment command based on the difference to obtain the modified first variable air volume valve adjustment command and the second variable air volume valve adjustment command.

9. The intelligent control system for a chemical laboratory according to claim 5, characterized in that, The gas protection algorithm program includes the following steps: Concentration change rate curves were constructed based on the concentration of harmful gases. The concentration change rate curve is classified and early warning is issued according to the preset concentration change value to obtain different levels of early warning response; Protection commands and alarm information are generated based on gas characteristic signals and early warning responses.

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