Reprocessed plastic composite smell detection device and method based on gas sensor

Abstract

The invention provides a recycled plastic composite odor detection device and method based on a gas sensor, and belongs to the technical field of plastic detection, the recycled plastic composite odor detection device comprises a device shell, a dynamic odor excitation module, a composite odor multi-mode sensing element combination and a signal self-adaptive multi-mode data processing engine; the composite smell dynamic excitation module is installed on the device shell, and the composite smell multi-mode sensing element combination and the signal self-adaption multi-mode data processing engine are installed on a PCB in the device shell. Through a technical chain of dynamic excitation-multi-mode sensing-data analysis, high-precision detection and pollution traceability of the composite odor of the regenerated plastic product are realized, a new solution is provided for quality control and green production of the regenerated plastic industry, reliable safety monitoring and environment-friendly emission monitoring means are provided for industrial enterprises, and the method has a wide application prospect. The whole detection process only needs several minutes, and compared with a gas chromatography detection method, the detection time is greatly shortened, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic detection, and in particular relates to a device and method for detecting composite odor of recycled plastic based on a gas sensor. Background Art

[0002] During the production process of recycled plastics, various volatile organic compounds (VOCs) are produced due to factors such as degradation of raw material additives and residual pollutants. The odors of these organic compounds mainly include: aldehydes: CH2O, C2H4O, ethers: CH3-S-CH3, C5H 12 / C6H 14 / C7H 16 , alcohols: C2H5SH, CH3OH, C2H5OH, amines: NH3, C3H9N, benzenes: C6H6, C7H8, C6H5C2H5, C6H5Cl, alkanes: CH4, C4H8O2, CH2Cl2, C2H4C l2 , oxides: CO, CO2, SO2, sulfides: H2S, chlorides: Cl2 (C6H5Cl), and dust particles: PM2.5, etc. These trace gases and dust not only affect product quality and user experience, but may also cause potential harm to human health.

[0003] Traditional detection methods have the following defects: 1. Manual olfactory identification: This method is highly subjective and cannot distinguish specific pollutant types (e.g., the difference in olfactory threshold between nonanal and styrene). 2. Gas chromatography-mass spectrometry (GC-MS): The equipment is expensive, requires professional operation, and cannot achieve real-time monitoring; 3. Universal electronic nose: The sensor selection is not optimized for the degradation products of recycled plastics, and the false alarm rate for low-concentration cross-sensitive substances (such as sulfur compounds) is high.

[0004] 4. The gas sensor matrix disclosed in existing technologies (such as CN113049520A) lacks dynamic excitation-detection coupling design and multimodal data processing for recycled plastic scenarios, resulting in insufficient detection sensitivity and practicality.

[0005] Due to the volatility and diffusion of odors, existing measurement techniques produce discrete and single results, failing to fully detect the various trace components of volatile odors emitted by recycled plastics. Therefore, the development of a detection device and method for dynamically activated recycled plastics and multimodal sensing of composite odors based on degradation products is of great significance for recycled plastic production, product quality improvement, and environmental pollution assessment. Summary of the Invention

[0006] The present invention aims to solve the problems of the prior art and adopts the following technical solutions: In a first aspect, the present invention provides a recycled plastic composite odor detection device based on a gas sensor, comprising: a device housing, a dynamic odor excitation module, a composite odor multimodal sensing element assembly, and a signal adaptive multimodal data processing engine; The composite odor dynamic excitation module is mounted on the device housing, and the composite odor multimodal sensing element combination and the signal adaptive multimodal data processing engine are mounted on a PCB board in the device housing; The PCB board is connected to the LCD touch screen, which runs the control, measurement, and display software. The signal adaptive multimodal data processing engine consists of dedicated embedded system hardware and multimodal data processing software.

[0007] Furthermore, the detection device first adds the recycled plastic sample to be tested into the composite odor volatilization filter cup, and the heating element, fan, and temperature control circuit dynamically stimulate the degradation of the recycled plastic additive and the volatilization of the residual pollutant odor, and deliver it to the device main body shell where the composite odor multimodal sensor element combination is located; the multimodal sensor element combination sensitive to the recycled plastic composite odor is started to obtain multimodal detection data; and the data is sent to the multimodal data processing engine of the measurement and control device through the interface bus and level conditioning circuit for data processing, identification of gas type and concentration, and determination of pollution level.

[0008] Furthermore, a dynamic odor stimulation module is used to release volatile organic compounds in recycled plastics under controllable temperature gradient conditions; a certain amount of recycled plastic sample is weighed, the recycled plastic particles are placed in a stainless steel filter cup, covered with a sealing lid, and VOCs are released step by step through a gradient heating program; in the electric heating hot air circulation system, the hot air flow flushes the surface of the recycled plastic particle sample, enhancing the transmission efficiency of odor substances.

[0009] Furthermore, a composite odor multimodal sensing element combination is composed of customized sensing elements targeting the characteristics of recycled plastic pollutants; heating excitation-odor release introduces the composite odor into the closed shell so that it reaches the sensor distribution array; the odor sensitive element combination for recycled plastic degradation products is activated, and multi-channel parallel data is collected in a variable temperature working mode to realize sensitive detection of the composite odor of recycled plastic.

[0010] Furthermore, a signal-adaptive multimodal data processing engine is a component specifically used to receive, integrate, analyze and process data of various different modalities, consisting of hardware and software. Different gas sensors have different gas-sensitive effects, which will cause changes in electrical signals such as impedance, current, voltage, and charge in the gas sensors. These multimodal electrical signals are converted into measurement data through A / D conversion. The odor-sensitive element combination for recycled plastic degradation products, combined with a multimodal data processing algorithm, processes a large amount of gas sampling data, identifies and distinguishes multiple signals of mixed gases, and accurately determines the types and concentrations of different gases. Through the LCD and PCB board interface, the measurement results are displayed and stored on the local LCD touch screen of the instrument. Through the WiFi interface, the measurement results are sent to the Internet of Things platform for remote display and storage. The air pump and solenoid valve are opened, the exhaust gas is discharged, and the system is cooled. The sensor element is restored and the detection device returns to standby status, waiting for the next detection.

[0011] Furthermore, the dynamic odor stimulation module consists of a sample filter cup, a sealing cover, a heating element, a fan, an air pump, a solenoid valve, a temperature measuring element, a control touchscreen, and a device housing. The sample filter cup, sealing cover, and control touchscreen are mounted on the housing. The heating element, fan, temperature measuring element, air pump, and solenoid valve are mounted on a PCB inside the housing. The exhaust outlet and cooling air inlet are mounted on the rear side of the housing. The air pump and solenoid valve control the inlet and outlet of gas via the touchscreen.

[0012] Furthermore, the composite odor multimodal sensing element combination is a specially customized VOCs sensor combination that is selectively responsive and sensitive to the composite odor components of recycled plastics, including at least one metal semiconductor heterojunction sensor or electrochemical sensor that is selective and multimodally responsive to aldehydes, hydrocarbons, ethers, alcohols, amines, benzenes, alkanes, oxides, chlorides and sulfur-containing compounds; it is arranged in a 5×6 matrix with a gap of ≥10mm, mounted on a PCB board, and connected to a signal-adaptive multimodal data processing engine via an RS485 bus.

[0013] Furthermore, the signal-adaptive multimodal data processing engine consists of embedded system hardware mounted on a PCB and an LCD touchscreen for human-computer interaction control. The embedded system hardware on the PCB includes an ESP32 processor, bus interface protocol circuitry, level conditioning circuitry, and software for recycled plastic composite odor sampling, component identification, and multimodal data processing running on an embedded operating system. An AC-DC module on the PCB provides power to all components onboard.

[0014] In a second aspect, the present invention provides a detection method for the recycled plastic composite odor detection device based on a gas sensor as described in the first aspect, comprising the following steps: Step 1: Sample pretreatment, dynamic stimulation of recycled plastic additives and residual pollutants, and active acquisition of complex odors; weigh a set amount of recycled plastic sample, place it into a stainless steel filter cup, and cover it with a sealed lid; place the stainless steel filter cup containing the sample into an electric heating hot air circulation system, control the temperature, and heat for a set time to fully release the odor components of the additives and residual pollutants in the recycled plastic; Step 2: Multimodal sensing detection of the composite odor; the composite odor volatilized from the recycled plastic sample is blown into the closed housing by a fan; the multimodal sensing element combination is activated to perform multimodal sensing detection on the composite odor of the recycled plastic; Step 3: Multimodal data processing, result display and storage: The detected multimodal signals are converted into digital signals and transmitted to the adaptive multimodal data processing unit, which processes the multimodal data to generate a composite odor component map, odor concentration distribution, and pollution level determination; The LCD touch screen runs human-machine operation and measurement and control software, and is responsible for the operation control, parameter setting, data storage, and result display functions of the entire detection device; the measurement results can be remotely displayed and stored through the WiFi interface and the Internet of Things; Step 4, measurement ends; turn on the air pump and solenoid valve, cool the system, and remove exhaust gas; the multimodal sensor combination customized for the release of specific gases from recycled plastics returns to its initial state, and the adaptive multimodal data processing engine returns to standby state.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are: 1. This invention achieves high-precision detection and pollution traceability of complex odors in recycled plastic products through the technology chain of dynamic excitation-multimodal sensing-data analysis, providing a new solution for quality control and green production in the recycled plastics industry, and offering industrial enterprises reliable safety monitoring and environmental emission monitoring methods.

[0016] 2. This method simulates the natural volatilization process of recycled plastics, performing complex odor detection within a closed enclosure, allowing for simultaneous measurement of multiple components and concentrations. This eliminates the subjectivity of manual olfactory analysis and provides objective and accurate results. The entire detection process takes only a few minutes, significantly shortening detection time and improving efficiency compared to gas chromatography. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0018] Figure 1 This is a schematic diagram of the general assembly of a recycled plastic composite odor detection device based on a gas sensor; Figure 2 Schematic diagram of a recycled plastic composite odor detection device module based on a gas sensor Figure 3 This is a schematic diagram of the back of a recycled plastic composite odor detection device based on a gas sensor; Figure 4 This is a schematic diagram of the PCB components of a recycled plastic composite odor detection device based on a gas sensor; Figure 5 This is a schematic diagram of the electrical connections of an odor-coupled sensor array for recycled plastic degradation products on a PCB; Figure 6 This is a schematic diagram of the signal adaptive multimodal data processing engine architecture; Figure 7 The software flow chart of the signal adaptive multimodal data processing engine is as follows; Among them, 101, detection device; 102, LCD touch screen; 103, recycled plastic sample inlet; 104, power supply and data signal connection from PCB to LCD; 105, sensor element analog connection; 106, sensor element digital connection; 107, exhaust gas exhaust pipe; 108, cooling air intake pipe; 109, AC-DC module DC output connection; 110, AC220V to AC-DC power converter power connection; 111, filter cup; 201, recycled plastic dynamic excitation module; 202, multi-modal sensor element combination; 203, multi-modal digital Data processing engine; 301, rear side of detection device; 302, exhaust outlet; 303, cooling gas inlet; 304, AC power socket and power switch; 401, PCB board; 402, odor-coupled sensitive element array for recycled plastic degradation products; 403, PCB to touch screen interface; 404, exhaust pump; 405, signal adaptive multimodal data processing engine; 406, fan; 407, heating element; 408, AC-DC power converter; 409, solenoid valve; 501, gas sensor power supply +; 502, gas sensor power supply -; 503, gas sensor data +; 504, gas sensor data -; 501, 502, 503, 504 constitute the interface bus and level conditioning module between the sensor array and the multimodal data processing engine; 505, aldehyde gas sensor; 506, ether gas sensor; 507, alcohol gas sensor; 508, amine gas sensor; 509, benzene gas sensor; 510, alkane gas sensor; 511, oxide gas sensor; 512, sulfide gas sensor; 513, chloride gas sensor; 514, dust particles 601, WiFi wireless communication interface; 602, digital communication interface; 603, analog signal interface; 604, 32-bit ESP32 processor; 605, on-chip memory; 606, on-chip 12-bit A / D converter; 701, boot system startup; 702, digital analog multimodal signal reception; 703, A / D conversion analog signal processing; 704, multimodal data processing; 705, LCD communication, local data display and storage; 706, WiFi wireless communication, remote data display and storage. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other without conflict.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Example 1 like Figures 1 to 7 As shown, the present application provides a recycled plastic composite odor detection device based on a gas sensor, comprising: The dynamic odor stimulation module is used to release volatile organic compounds (VOCs) from recycled plastics under controllable temperature gradient conditions. A certain amount of recycled plastic sample (e.g., 50 ± 0.1 g) is weighed, and the recycled plastic particles are placed in a stainless steel filter cup with a sealed lid. VOCs are released step by step through a gradient temperature ramp (20°C → 30°C → 40°C → 50°C → 60°C). In the electrically heated hot air circulation system, the hot air flow washes over the surface of the recycled plastic particle sample, enhancing the efficiency of odorant transmission. The composite odor multimodal sensor element combination consists of customized sensor elements tailored to the characteristics of recycled plastic pollutants. A heating excitation-odor release process introduces the composite odor into a closed enclosure, allowing it to reach the sensor array. The odor-sensitive element combination for recycled plastic degradation products is activated, and multi-channel parallel data acquisition is performed in a variable temperature operating mode to achieve sensitive detection of the composite odor of recycled plastic. This process can be summarized as: gas excitation-sensing coupling control, multimodal sensing, multi-channel parallel sampling, and multimodal signals and data are delivered to the multimodal data processing engine via different paths. The signal-adaptive multimodal data processing engine, a component specifically designed to receive, integrate, analyze, and process data from multiple modalities, consists of both hardware and software. Different gas sensors have different gas-sensing effects, which can cause changes in electrical signals such as impedance, current, voltage, and charge. These multimodal electrical signals are converted into measurement data through A / D conversion. A combination of odor-sensitive elements for recycled plastic degradation products, combined with a multimodal data processing algorithm, processes large amounts of gas sampling data, identifies and distinguishes the various signals of mixed gases, and accurately determines the type and concentration of different gases. Measurement results are displayed and stored on the instrument's local LCD touchscreen via the LCD and PCB interface. Through the WiFi interface, measurement results are sent to the IoT platform for remote display and storage. The air pump and solenoid valve open, exhaust gas is discharged, and the system cools. The sensor element recovers, and the detection device returns to standby mode, awaiting the next test.

[0022] A device and method for detecting composite odors from recycled plastics based on a gas sensor. The detection device comprises a dynamic excitation module for composite odors from recycled plastics, a composite odor multimodal sensor assembly, and a signal-adaptive multimodal data processing engine. The dynamic excitation module is mounted on the device housing, while the composite odor multimodal sensor assembly and the signal-adaptive multimodal data processing engine are mounted on a printed circuit board (PCB) within the housing. The PCB is connected to an LCD touchscreen, which runs control, measurement, and display software. The signal-adaptive multimodal data processing engine consists of dedicated embedded system hardware and multimodal data processing software. The detection device first adds a recycled plastic sample to a composite odor volatilization filter cup. A heating element, fan, and temperature control circuit dynamically excite the odors of degraded recycled plastic additives and residual pollutants, which are then volatilized and delivered to the device housing, where the composite odor multimodal sensor assembly resides. The multimodal sensor assembly, sensitive to the composite odors from recycled plastics, is activated to acquire multimodal detection data. This data is then transmitted to the multimodal data processing engine of the measurement and control device via an interface bus and level conditioning circuit for data processing to identify the gas type and concentration and determine the contamination level. The measurement and control software running on the touch screen performs parameter setting, operation control, and result display for the entire device and sends the data to the remote data monitoring platform through the Internet of Things.

[0023] This invention, specifically designed for recycled plastic applications, uses a detection method chain consisting of dynamic excitation, multimodal sensing, coupled detection design, and data processing to detect and display trace components of volatile gases from recycled plastics. The results are highly reproducible, providing a reference for recycled plastic production and quality improvement.

[0024] 1.1 Recycled plastic dynamic excitation module, simulating the natural volatilization environment of recycled plastic, integrating a gradient temperature control unit (gradient temperature increase of 20℃~30℃~40℃~50℃~60℃±1℃) and a hot air flow generator (flow rate of 3L / min), simulating the natural volatilization environment of recycled plastic to stimulate characteristic odor; Measure the weight of recycled plastic particles (50g), measure the concentration of a certain gas in a certain volume, and calculate the amount of volatile matter contained in the unit weight (per gram) of the sample in the data processing engine.

[0025] 1.2 Composite odor multimodal sensor element combination, targeting the volatile gas characteristics of recycled plastics. Due to the complex composition of recycled plastic additives and pollutant residues, a multimodal sensor element combination is selected. Different sensitive effects are selected for different gases to convert them into different forms of electrical signals, such as charge, voltage, current, conductivity and other different modal signals.

[0026] Taking toluene gas released from common pollutant residues in recycled plastics as an example, a SnO2-based sensor was selected to enhance the selective response to toluene by doping with Pt nanoparticles.

[0027] This technical solution is composed of digital sensors and analog sensors according to signal classification, and is composed of more than ten categories and dozens of types of metal oxide sensors, semiconductor gas sensors, and electrochemical sensors according to sensitive materials, including but not limited to the following categories: WO3-Pt nanoparticle sensor: specifically designed for detecting aldehydes (such as nonanal, detection limit 0.05ppm); SnO2-ZnO heterojunction sensor: selective response to benzene series (toluene / ethylbenzene); CuO-In2O3 thin film sensor: Identification of sulfur-containing compounds (such as dimethyl disulfide); TiO2 nanotube array sensor: captures chlorides (such as HCl produced by PVC degradation); Molecularly imprinted polymer (MIP) sensors: targeting typical pollutants in recycled plastics (such as bisphenol A); This technical solution includes but is not limited to the parameters of some customized special sensors for recycled plastics given in Table 1.

[0028] Table 1 Parameters of some recycled plastic customized gas sensors

[0029] The sensor space layout adopts matrix layout design, such as Figure 4 As shown, the spacing is ≥10mm to avoid cross interference.

[0030] The analog signal obtained by the combination of multi-channel parallel sampling and redundant sensors is directly connected to the AD module of the multi-modal data processing engine through the analog pin. The digital signal obtained is sent to the multi-modal data processing engine through the 485 bus. Figure 5 shown.

[0031] 1.3 Multimodal data processing engine, in view of the special conditions and special requirements of recycled plastic composite odor detection, the multimodal data processing engine of this technical solution consists of a special embedded processing system, the structure of which is as follows: Figure 6 As shown, it is composed of a multimodal data processing software, and the software flow chart is as follows Figure 7 shown.

[0032] In order to process large amounts of multimodal data, the central processing unit is a 32-bit ESP32 processor. In order to achieve a certain level of detection accuracy, the on-chip AD module uses 12-bit conversion accuracy to process analog sensor signals.

[0033] Considering multimodal data processing, a UART interface is used between the multimodal data processing engine and the LCD. A 485 interface is used for the digital interface between the multimodal data processing engine and the multimodal sensing unit. The analog signal between the multimodal data processing engine and the multimodal sensing unit is connected to the on-chip A / D conversion module via an analog signal interface. The multimodal data processing engine is connected to the remote IoT monitoring platform via a WiFi interface.

[0034] Through the embedded system hardware based on ESP32 and its rich multimodal signal interfaces, coupled with the multimodal data processing software running on it, a high-precision sensor data processing engine dedicated to environmental testing and multimodal sensing and detection of recycled plastic composite odors has been formed. The software samples the analog signal of the analog gas sensor through the analog pins of ESP32 and quantizes it using the ADC module inside ESP32; it receives the digital signal of the digital gas sensor through the digital pins of ESP32 and performs data processing. The multimodal data processing software flow chart is shown in the figure below. Figure 7 shown.

[0035] Example 2. This example provides a detection method for a recycled plastic composite odor detection device based on a gas sensor. The detection method is a dynamic excitation-multimodal sensing-data analysis method chain, specifically involving simulating the natural volatilization process of recycled plastic to dynamically stimulate the release of volatile compounds (VOCs); a signal-adaptive multimodal sensing element combination to perform comprehensive detection of the recycled plastic composite odor, and a multimodal data processing engine to perform odor type identification and category analysis, providing the volatile component composition, concentration distribution, and contamination level of the tested recycled plastic product. This method is particularly suitable for rapid identification of volatile organic compounds (VOCs) and excessive warning of VOCs in recycled plastic granulation production lines. The detection method includes the following steps: 2.1 Dynamic excitation stage: sample pretreatment, simulating the natural volatilization of recycled plastics to produce complex odors.

[0036] Weigh a certain amount of recycled plastic sample (e.g., 50 ± 0.1 g), place the recycled plastic particles in a stainless steel filter cup, cover with a sealing lid, and release VOCs step by step through a gradient temperature program (20°C → 30°C → 40°C → 50°C → 60°C); In the electric heating hot air circulation system, the hot air flow washes the surface of the recycled plastic particle sample, enhancing the transmission efficiency of odor substances; 2.2 Signal acquisition stage: heating excitation-odor release, introducing the complex odor into the closed shell so that it reaches the sensor distribution array; Launched a combination of odor-sensitive elements for recycled plastic degradation products, acquiring data in parallel across multiple channels under variable temperature operation mode to achieve sensitive detection of composite odors of recycled plastics; This process can be summarized as: gas excitation-sensing coupled control, multi-mode sensing, multi-channel parallel sampling, and multi-modal signals and data delivered to the multi-modal data processing engine through different paths; 2.3 Multimodal data processing stage: Different gas sensors have different gas sensing effects, which will cause changes in electrical signals such as impedance, current, voltage, and charge in the gas sensors. These multimodal electrical signals are converted into measurement data through A / D conversion; The odor-sensing element combination for recycled plastic degradation products, combined with a multimodal data processing algorithm, processes a large amount of gas sampling data, identifies and distinguishes multiple signals of mixed gases, and accurately determines the type and concentration of different gases; Multimodal data processing algorithms, including analog signal processing and digital signal processing.

[0037] The analog signal from the gas sensor is sent directly to the processor's A / D module via the ESP32 analog pin and converted into a digital signal, ready to be processed along with signals from other digital sensors arriving via the 485 bus.

[0038] The digital signal of the gas sensor enters the ESP32 processor through the 485 bus for data processing. Some of the algorithms are as follows: a Data correction algorithm before and after odor stimulation: GS = GS2- GS1------Equation 1 Among them: the precipitation concentration of a certain odor of GS; the concentration of a certain odor after stimulation of GS2; the initial concentration of a certain odor in the shell before stimulation of GS1.

[0039] b Sampling data singular value processing algorithm: IfGS out >GS limit thenGS out = 0;------Formula 2 Among them: GS out Detection value of a certain odor, GS limit Limit value of an odor sensor. c Measurement value fluctuation suppression algorithm: ------Formula 3 in: The concentration of a certain odor precipitation, The i-th sampling value of a certain odor.

[0040] d. Calculation of the amount of odor released per unit weight of sample: ------Formula 4 Including: Amount of odor released per unit sample , The concentration of a certain odor precipitation, Effective volume of the instrument housing, weight of 50g recycled plastic sample.

[0041] e. Spectral diagram of compound odor groups: ------Formula 5 in: The height of a certain odor precipitation line, Proportional coefficient, The total amount of a particular odor released. A composite odor component map is a set of vertical lines of varying heights. Different vertical lines represent different odor names, and the height of the vertical lines is proportional to the total amount of odor released.

[0042] The composite odor group spectrum is composed of the height combination of all odor precipitation straight lines.

[0043] 2.4 Measurement result processing: Through the LCD and PCB board interface, the measurement results are displayed and stored on the instrument's local LCD touch screen; through the WiFi interface, the measurement results are sent to the IoT platform for remote display and storage; 2.5 The measurement is completed; the air pump and solenoid valve are opened, the exhaust gas is discharged, and the system is cooled; The sensor element recovers and the detection device returns to standby mode, waiting for the next detection; The advantages of the present invention are that the present invention realizes high-precision detection and pollution tracing of complex odors of recycled plastic products through the technical chain of dynamic excitation-multimodal sensing-data analysis, provides a new solution for quality control and green production in the recycled plastic industry, and provides industrial enterprises with reliable safety monitoring and environmental emission monitoring means.

[0044] This method simulates the natural volatilization process of recycled plastics, performing complex odor detection within a closed enclosure, allowing simultaneous measurement of multiple components and concentrations. This eliminates the subjectivity of manual olfactory analysis and provides objective and accurate results. The entire detection process takes only a few minutes, significantly shortening detection time and improving efficiency compared to gas chromatography.

[0045] Using the technical solution of the present invention, the inventors have developed a recycled plastic trace component detector.

[0046] The technical solution of the present invention is further specifically described through embodiments and in combination with the accompanying drawings in the specification.

[0047] like Figure 1-Figure 7Serial number 109 is the DC output connection of the AC-DC module, used for power transmission to the AC-DC module; Serial number 110 is the power connection from AC220V to the AC-DC power converter, used for power supply; Serial number 111 is the filter cup, used for filtration; Serial number 201 is the recycled plastic dynamic excitation module; Serial number 202 is the multimodal sensor element assembly; Serial number 203 is the multimodal data processing engine; Serial number 301 is the rear side of the detection device; Serial number 302 is the exhaust outlet; Serial number 303 is the cooling gas inlet; Serial number 304 is the AC power socket and power switch; Serial number 401 is the PCB board; Serial number 402 is an odor-coupling sensor array for recycled plastic degradation products; Serial number 403 is a PCB to touch screen interface; Serial number 404 is an exhaust pump; Serial number 405 is a signal adaptive multimodal data processing engine; Serial number 406 is a fan; Serial number 407 is a heating element; Serial number 408 is an AC-DC power converter; Serial number 409 is a solenoid valve; Serial number 501 is a gas sensor power supply +; Serial number 502 is a gas sensor power supply -; Serial number 503 is a gas sensor data +; Serial number 504 is a gas sensor data -; Serial number 501, Serial number 502, Serial number 50 3. Serial number 504 constitutes the interface bus and level conditioning module between the sensor array and the multimodal data processing engine; Serial number 505 is an aldehyde gas sensor; Serial number 506 is an ether gas sensor; Serial number 507 is an alcohol gas sensor; Serial number 508 is an amine gas sensor; Serial number 509 is a benzene gas sensor; Serial number 510 is an alkane gas sensor; Serial number 511 is an oxide gas sensor; Serial number 512 is a sulfide gas sensor; Serial number 513 is a chloride gas sensor; Serial number 514 is a dust particle temperature and humidity sensor or other sensor; Serial number 601 The following are the 32-bit ESP32 processors: Serial number 605 is the on-chip memory; Serial number 606 is the on-chip 12-bit A / D converter; Serial number 701 is the boot system startup; Serial number 702 is the digital analog multimodal signal reception; Serial number 703 is the A / D conversion analog signal processing; Serial number 704 is the multimodal data processing; Serial number 705 is the LCD communication, and the data is displayed locally as storage; Serial number 706 is the WiFi wireless communication, and the data is displayed remotely as storage.

[0048] Turn on the power switch 304 on the rear side 301 of the detection device body, and the AC-DC power conversion module 408 supplies power to the PCB board 401 and the LCD touch screen 102, and the module 201 in the detection device begins to enter the detection standby state.

[0049] A certain amount (50 g) of recycled plastic sample is added into the filter cup 111 in the detection device 101 through the recycled plastic sample inlet 103 .

[0050] The recycled plastic sample inlet 103 is composed of a stainless steel filter cup and a sealing cover.

[0051] The fan 406 and the heating element 407 are controlled by the LCD touch screen 102 to start the process of obtaining the composite odor by dynamically stimulating the recycled plastic.

[0052] The obtained recycled plastic composite odor enters the closed shell of the detection device 101, and the LCD touch screen 102 starts the signal adaptive multimodal odor data analysis engine 405, aldehyde gas sensor 505, ether gas sensor 506, alcohol gas sensor 507, amine gas sensor 508, benzene gas sensor 509, alkane gas sensor 510, oxide gas sensor 511, sulfide gas sensor 512, chloride gas sensor 513, dust particle, temperature and humidity sensor 514 and other components on the PCB board 401 to start detection.

[0053] An odor-coupled sensitive element array for recycled plastic degradation products, powered by sensor DC power lines 501 and 502, detects trace components of different odors. Various measurement signals are sent to the 32-bit ESP32 processor 604, on-chip memory 605, and on-chip 12-bit A / D converter 606 of the adaptive odor analysis engine 203 through gas sensor data +503, gas sensor data -504, and multimodal data via a digital communication interface 602 and an analog signal interface 603 for data processing. The sensors are connected using a sensor element analog connection 105 and a sensor element digital connection 106 for testing.

[0054] The measurement data is sent to the LCD touch screen 102 through the PCB to touch screen interface 403, the PCB to LCD power and data signal connection 104, and the results are displayed locally. The data is sent to the Internet of Things platform for remote display and storage through the WiFi interface 601 and wireless network.

[0055] After the measurement is completed, the LCD touch screen 102 controls the air pump 404 and the solenoid valve 409. The air pump 404 is provided with an exhaust gas exhaust pipe 107, and the solenoid valve 409 is provided with a cooling air inlet pipe 108. The air inlet 303 and the exhaust gas outlet 302 are opened to cool the main body of the device, reset the multimodal sensor element, and the circuit system enters a standby state, waiting for the next detection task.

[0056] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any other form. Any technician familiar with the present invention may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes for application in other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A recycled plastic composite odor detection device based on a gas sensor, characterized in that: include: Device housing, dynamic odor excitation module, composite odor multimodal sensing element assembly, and signal adaptive multimodal data processing engine; The composite odor dynamic excitation module is mounted on the device housing, and the composite odor multimodal sensing element combination and the signal adaptive multimodal data processing engine are mounted on a PCB board in the device housing; The PCB board is connected to the LCD touch screen, which runs the control, measurement, and display software. The signal adaptive multimodal data processing engine consists of dedicated embedded system hardware and multimodal data processing software.

2. A recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The detection device first adds the recycled plastic sample to be tested into the composite odor volatilization filter cup. The heating element, fan, and temperature control circuit dynamically stimulate the degradation of the recycled plastic additives and the volatilization of the residual pollutants, and deliver them to the main body shell of the device where the composite odor multimodal sensor element combination is located; the multimodal sensor element combination sensitive to the recycled plastic composite odor is activated to obtain multimodal detection data; and the data is sent to the multimodal data processing engine of the measurement and control device through the interface bus and level conditioning circuit for data processing, identification of gas type and concentration, and determination of pollution level.

3. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The dynamic odor stimulation module is used to release volatile organic compounds in recycled plastics under controllable temperature gradient conditions; a certain amount of recycled plastic sample is weighed, the recycled plastic particles are placed in a stainless steel filter cup, covered with a sealing lid, and VOCs are released step by step through a gradient temperature rise program; in the electric heating hot air circulation system, the hot air flow flushes the surface of the recycled plastic particle sample, enhancing the transmission efficiency of odor substances.

4. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: A composite odor multimodal sensing element assembly consisting of custom-designed sensing elements specific to recycled plastic contaminants; Heating excitation-odor release, introducing the complex odor into the closed shell so that it reaches the sensor distribution array; A combination of odor-sensitive elements for recycled plastic degradation products was launched, and multi-channel parallel data collection was carried out in variable temperature working mode to achieve sensitive detection of the composite odor of recycled plastics.

5. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The signal-adaptive multimodal data processing engine is a component specifically designed to receive, integrate, analyze, and process data from multiple modalities. It consists of both hardware and software. Different gas sensors have different gas-sensing effects, which can cause changes in impedance, current, voltage, and charge electrical signals within the gas sensors. These multimodal electrical signals are converted into measurement data through A / D conversion. A combination of odor-sensitive elements for recycled plastic degradation products, combined with a multimodal data processing algorithm, processes large amounts of gas sampling data, identifies and distinguishes the various signals of mixed gases, and accurately determines the types and concentrations of different gases. Measurement results are displayed and stored on the instrument's local LCD touchscreen via the LCD and PCB board interfaces. Measurement results are also sent to the IoT platform for remote display and storage via the WiFi interface. The air pump and solenoid valve open, exhausting the exhaust and cooling the system. The sensor element recovers and the detection device returns to standby mode, waiting for the next detection.

6. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The dynamic odor stimulation module consists of a sample filter cup, a sealing cover, a heating element, a fan, an air pump, a solenoid valve, a temperature measuring element, a control touch screen, and a device housing; the sample filter cup, sealing cover, and control touch screen are installed on the device housing, the heating element, fan, temperature measuring element, air pump, and solenoid valve are installed on the PCB board inside the device housing, and the exhaust gas outlet and cooling air inlet are installed on the rear side of the device housing; the entry and exit of gas are controlled by the air pump and solenoid valve through the touch screen.

7. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The composite odor multimodal sensing element combination is a specially customized VOCs sensor combination that has selective response and is sensitive to the composite odor components of recycled plastics. It includes at least one metal semiconductor heterojunction sensor or electrochemical sensor that has selective and multimodal response to aldehydes, hydrocarbons, ethers, alcohols, amines, benzenes, alkanes, oxides, chlorides and sulfur-containing compounds respectively; it is arranged in a 5×6 matrix with a gap of ≥10mm, mounted on a PCB board, and connected to the signal adaptive multimodal data processing engine via the RS485 bus.

8. The recycled plastic composite odor detection device based on a gas sensor as claimed in claim 1, characterized in that: The signal-adaptive multimodal data processing engine consists of embedded system hardware mounted on a PCB and an LCD touch screen for human-computer interaction control. The PCB with the embedded system hardware includes an ESP32 processor, a bus interface protocol circuit, a level conditioning circuit, and recycled plastic composite odor sampling, component identification, and multimodal data processing software running on an embedded operating system. The AC-DC module on the PCB provides power to all components on the board.

9. A detection method for a recycled plastic composite odor detection device based on a gas sensor as claimed in claims 1 to 8, characterized in that: The steps include: Step 1: Sample pretreatment, dynamic stimulation of recycled plastic additives and residual pollutants, and active acquisition of complex odors; weigh a set amount of recycled plastic sample, place it into a stainless steel filter cup, and cover it with a sealed lid; place the stainless steel filter cup containing the sample into an electric heating hot air circulation system, control the temperature, and heat for a set time to fully release the odor components of the additives and residual pollutants in the recycled plastic; Step 2: Multimodal sensing detection of the composite odor; the composite odor volatilized from the recycled plastic sample is blown into the closed housing by a fan; the multimodal sensing element combination is activated to perform multimodal sensing detection on the composite odor of the recycled plastic; Step 3: Multimodal data processing, result display and storage: The detected multimodal signals are converted into digital signals and transmitted to the adaptive multimodal data processing unit, which processes the multimodal data to generate a composite odor component map, odor concentration distribution, and pollution level determination; The LCD touch screen runs the human-machine operation and measurement and control software, and is responsible for the operation control, parameter setting, data storage, and result display functions of the entire detection device; the measurement results can be remotely displayed and stored through the WiFi interface and the Internet of Things; Step 4, measurement ends; turn on the air pump and solenoid valve, cool the system, and remove exhaust gas; the multimodal sensor combination customized for the release of specific gases from recycled plastics returns to its initial state, and the adaptive multimodal data processing engine returns to standby state.

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