Volatile condensate detection method based on surface acoustic wave technology and detection instrument thereof

Abstract

The invention discloses a volatile condensate detection method based on a surface acoustic wave technology and a detection instrument thereof. The detection method comprises the following steps: detecting the accumulation, fusion and dripping processes of an object to be detected on the surface of the surface acoustic wave sensor through the surface acoustic wave sensor arranged at a position to be detected, judging the liquid drop state according to the peak change of a response curve, and triggering an alarm when the change of a rising edge exceeds a threshold value. The instrument comprises a surface acoustic wave sensor, a loss measurement module and a data processing module, and can analyze the accumulation, fusion and dripping states of the condensate and convert the change into a loss signal; the system further comprises a microcontroller, a high-precision acquisition unit, a data acquisition and processing unit and a coaxial cable, and remote signal transmission and remote monitoring are achieved. The system and the method can realize real-time monitoring of volatile condensates in dangerous places, and have the advantages of high sensitivity, fast response, good safety and support of remote multi-point detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection, and particularly relates to a volatile condensate detection method based on a surface acoustic wave technology and a detection instrument thereof. BACKGROUND

[0002] In the industrial production process, volatile organic compounds often volatilize into the production environment with organic solvents or water vapor. In actual production, the equipment and production environment need to be cleaned regularly to avoid excessive accumulation of volatile organic compounds in the gaps, slits and wall of the equipment, which may cause combustion and explosion under certain conditions. At present, the condensation amount and condensation behavior of volatile organic compounds at different positions in the production environment are mainly determined by production experience and visual judgment, and there is no related detection instrument and method. The risk is reduced mainly by shortening the continuous production time and increasing the flushing frequency, and there is a lack of objective judgment on the real-time state and risk of the accumulation, dripping and flow of volatile organic compounds.

[0003] Chinese patent CN119643754B discloses a detection method for the concentration of specific gas in an explosion hazard place. The method uses solid-phase microextraction sampling in the field, and the collected sample is detected offline by a surface acoustic wave gas chromatograph. The concentration of the target component gas in the explosion hazard place is calculated and analyzed according to the detection result, and finally the rapid detection of the concentration of specific gas in the explosion hazard place is realized. Although the sampling and detection method is safe and the detection time period is greatly shortened, the method can only detect specific gas and cannot detect the real-time state of the accumulation, dripping and flow of volatile condensate. It also cannot meet the needs of real-time detection and alarm.

[0004] Therefore, there is an urgent need for a method for detecting the real-time state of the accumulation, dripping and flow of volatile condensate in a dangerous place to provide support for safe handling. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art that cannot detect the real-time state of the accumulation, dripping and flow of volatile condensate in a dangerous place, and to provide a volatile condensate detection method based on a surface acoustic wave technology and a detection instrument.

[0006] To solve the above technical problems, the technical solution of the present application provides a volatile condensate detection method based on a surface acoustic wave technology, which comprises the following steps: Step 1, placing the surface acoustic wave sensor at the position to be detected; Step 2, converting the change of the surface acoustic wave sensor loss measured by the loss measurement module into a digital signal by the high-precision acquisition module, and generating a response curve; Step 3, performing real-time analysis on the response curve of step 2 by the data processing module to obtain the accumulation, fusion and dripping state of the to-be-detected substance The accumulation, fusion, and dripping process of the analyte in step 3 includes: a. The non-smooth jitter in the response curve indicates that the vapor of the test object condenses on the surface acoustic wave sensor surface and forms droplets, indicating that it is in an accumulation state. b. The droplets are determined to be in a fusion process by the presence of multiple spikes on the response curve with rising edges ranging from 0.004 dB to 2 dB. c. If the response curve shows a steep rising edge and a high peak, it is determined that the droplet is either dripping vertically or sliding along the surface of the surface acoustic wave sensor, and has entered the dripping state.

[0007] When the range of the rising edge variation exceeds the set threshold, the alarm module generates an audible and visual alarm signal.

[0008] To address the aforementioned technical problems, this application also provides a detection instrument for a volatile condensate detection method based on surface acoustic wave technology, used for monitoring the accumulation, fusion, and dripping processes of volatile condensates, including: A surface acoustic wave sensor unit is used to sense the accumulation, fusion, and dripping states of volatile condensates and convert the accumulation, fusion, and dripping states into loop losses. The host unit includes: A loss measurement module, wherein the loss measurement module is used to measure the loss change of the surface acoustic wave sensor; A high-precision acquisition module is used to convert the loss changes of the surface acoustic wave sensor measured by the loss measurement module into digital signals, and transmit them to the server via a network transmission unit; and The data processing module is used to generate response curves in real time and detect the accumulation, fusion, and dripping states of the analyte in real time based on the response curves. Furthermore, the data processing module also includes a data acquisition and processing unit, which can be deployed as software within the host unit. This unit is used to configure the sampling rate, output signal amplitude, and selection of sampling channels for the data acquisition of digital signals converted by the high-precision acquisition module, and to process, display, and store the digital signals. The microcontroller module is used to adjust the input signal frequency of the surface acoustic wave sensor and receive the output signal from the high-precision acquisition module. A coaxial cable is used for long-distance, low-loss transmission of the input and output signals of the surface acoustic wave sensor; The alarm module is used to generate an alarm signal when the change in loss exceeds a set threshold.

[0009] The loss measurement module includes: A signal generator, wherein the signal generator is used to generate two radio frequency signals with frequencies ranging from 30MHz to 4000MHz; A filter, wherein the filter is used to reduce high-order harmonic energy in radio frequency signals; Automatic gain control module, which is used to amplify signals and improve the dynamic range of the instrument; An amplitude discriminator is used to convert the change in loss of the surface acoustic wave sensor into a voltage signal, with a conversion ratio of 30mV / dB.

[0010] The loss measurement resolution of the loss measurement module is 0.001dB.

[0011] As another improvement to the above-mentioned instrument, the surface acoustic wave sensor unit is installed separately from the main unit. The surface acoustic wave sensor unit is installed at the position to be measured, and the main unit is installed in a safe area.

[0012] As a further improvement to the aforementioned instrument, the data acquisition and processing unit is used for local hard disk read / write and local hard disk capacity monitoring.

[0013] Compared with existing technologies, the advantages of this application are: 1. This application uses a surface acoustic wave sensor unit with low excitation energy and small device amplitude. After long-term operation, the surface acoustic wave sensor does not generate significant heat, which meets the safety requirements of places with potential explosion hazards. 2. This application uses the loss variation of surface acoustic wave devices to characterize the accumulation of volatile condensates. It has the characteristics of fast response speed (response time on the order of milliseconds), small loss variation with temperature relative to phase, wide temperature range, and good temperature stability. It can track the morphological changes of accumulation, fusion and dripping of volatile condensates. 3. This application uses a signal generator, an automatic gain module, and an amplitude discriminator to form a loss measurement circuit, which has a loss measurement resolution of 0.001dB and high sensitivity.

[0014] 4. This application allows the sensor and the main unit to be installed in different locations. Specifically, the sensor can be installed at the location to be measured, while the main unit can be installed in other locations. This reduces the impact of the measurement location, expands the instrument's application scenarios, and makes the instrument's design, manufacturing, installation, and use more convenient.

[0015] 5. This application uses a host computer that can carry multiple surface acoustic wave sensor units, realizing multi-point detection of volatile condensates. Attached Figure Description

[0016] Figure 1 The diagram shows the components of an instrument for detecting volatile coagulants. Figure 2The diagram shown is a composition diagram of the loss measurement module; Figure 3 The diagram shown is a schematic of the polyethylene glycol-200 testing apparatus. Figure 4 The figure shown is the curve of instrument response as a function of agglomerate accumulation in Embodiment 2 of this application; Figure 5 The image shows that the surface agglomerates on the surface of the surface acoustic wave sensor in the first stage of Embodiment 2 of this application are distributed in a dotted pattern. Figure 6 The figure shown is the instrument response characteristic curve for the first stage of Embodiment 2 of this application; Figure 7 The image shows the characteristics of the surface agglomerates on the surface of the surface acoustic wave sensor in the second stage of Embodiment 2 of this application; Figure 8 The figure shown is the instrument response characteristic curve for the second stage of Embodiment 2 of this application; Figure 9(a) shows the surface condensate on the surface of the surface acoustic wave sensor before it drips in the third stage of Embodiment 2 of this application; Figure 9(b) shows the surface agglomerates dripping onto the surface of the surface acoustic wave sensor in the third stage of Embodiment 2 of this application; Figure 10 The figure shows the agglomerate dripping response of Embodiment 2 of this application, which is approximately 8.451 dB; Figure 11 The figure shown is the curve of instrument response as a function of agglomerate accumulation in Embodiment 3 of this application; Figure 12 The image shows that the surface agglomerates on the surface of the surface acoustic wave sensor in the first stage of Embodiment 3 of this application are distributed in a dotted pattern. Figure 13 The figure shown is the instrument response characteristic curve for the first stage of Embodiment 3 of this application; Figure 14 The image shows the characteristics of the surface agglomerates on the surface of the surface acoustic wave sensor in the second stage of Embodiment 3 of this application; Figure 15 The figure shown is the instrument response characteristic curve for the second stage of Embodiment 3 of this application; Figure 16(a) shows the surface condensate on the surface of the surface acoustic wave sensor before it drips in the third stage of Embodiment 3 of this application; Figure 16(b) shows the surface agglomerates dripping onto the surface of the surface acoustic wave sensor in the third stage of Embodiment 3 of this application; Figure 17 The image shows the first dripping response of the aggregate in Embodiment 3 of this application; Figure 18 The image shows the second drip response of the aggregate in Embodiment 3 of this application; Figure 19 The image shows the third drip response of the aggregate in Embodiment 3 of this application. Detailed Implementation

[0017] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0018] Example 1 like Figure 1 As shown, this embodiment provides the components of a volatile condensate detection instrument, including a surface acoustic wave (SAW) sensor unit, a coaxial cable unit, and a main unit. The SAW sensor unit senses the accumulation, fusion, and dripping states of condensates, converting changes in condensates into loop losses. The coaxial cable unit transmits the input and output signals of the SAW sensor over long distances with low loss. The main unit measures the loss changes of the SAW sensor and stores the collected data locally in real time. Its data acquisition and processing unit enables comprehensive analysis of condensate accumulation morphology and automatic alarm functions.

[0019] The host unit includes a loss measurement module, a microcontroller module, a high-precision acquisition module, and a data acquisition and processing unit. The loss measurement module measures the loss change of the surface acoustic wave sensor; the high-precision acquisition module converts the analog signal output from the loss measurement module into a digital signal; the microcontroller module adjusts the input signal frequency of the surface acoustic wave sensor module, receives the output signal from the high-precision acquisition module, and communicates with the computer. The data processing module also includes a data acquisition and processing unit, deployed as software within the host unit, used to configure the sampling rate, output signal amplitude, and sampling channel selection for the digital signal converted by the high-precision acquisition module, and to process, display, and store the digital signal.

[0020] The loss measurement module in the main unit, such as Figure 2 As shown, it consists of a signal generator, a filter, an automatic gain control module, and an amplitude discriminator. The signal generator module generates two RF signals 1, the frequency of which should be the operating frequency of the surface acoustic wave sensor; the filter reduces the high-order harmonic energy in RF signal 1; the automatic gain control module amplifies the signal and improves the dynamic range of the instrument; the amplitude discriminator converts the change in the loss of the surface acoustic wave sensor into a voltage signal with a conversion ratio of 30mV / dB.

[0021] Example 2 To further illustrate the scope of application of this application, this application provides specific examples of testing using polyethylene glycol-200 as a sample.

[0022] Polyethylene glycol-200 was used as the sample for testing. The principle of the testing device is as follows: Figure 3As shown, the surface acoustic wave (SAW) sensor is mounted above a liquid polyethylene glycol-200. The SAW liquid is heated to 100°C using a constant-temperature heater, causing the volatilized SAW vapor to condense and accumulate on the surface of the sensor. The host interface displays the real-time changes in SAW sensor loss. The test lasts approximately 7.5 hours. Figure 4 As shown.

[0023] The accumulation process of condensates on the surface of a surface acoustic wave sensor can be divided into three stages.

[0024] Stage 1: Polyethylene glycol-200 vapor condenses on the surface of the surface acoustic wave sensor, forming small droplets. As time increases, the droplets become increasingly dense, such as... Figure 5 As shown. The instrument response varies with the amount of droplet accumulation. Changes in the size and shape of the droplet on the surface acoustic wave sensor surface cause fluctuations in the response curve, resulting in an unsmooth response curve, such as... Figure 6 As shown.

[0025] The second stage: After the boundaries of the small droplets overlap, multiple small droplets merge into one large droplet. This droplet merging behavior causes a sharp peak on the instrument's response curve. For example... Figure 7 As shown, with the increase of condensation, more large droplets appear on the surface of the surface acoustic wave sensor, resulting in multiple spikes on the instrument's response curve. Figure 8 As shown, the rising edge of the peak on the response curve is gentle and the peak value is small. The change in the rising edge of the peak in the second stage is approximately in the range of 0.004~1dB.

[0026] The third stage: As the amount of condensate accumulates, the balance between the surface tension and gravity of the large droplets is broken, and the droplets begin to move, either dripping vertically or sliding along the surface of the surface acoustic wave sensor. Figure 9(a) shows the condensate on the surface acoustic wave sensor before it drips, and Figure 9(b) shows the condensate after it drips. Droplet movement causes significant changes in loss, resulting in a sharp rise and high peak on the response curve, such as... Figure 10 As shown.

[0027] In this embodiment, the third-stage agglomerate dripping response is approximately 8.451 dB. Agglomerate dripping indicates a risk, and the instrument issues an alarm.

[0028] Example 3 To further illustrate the scope of this application, specific embodiments are provided for testing using triacetin as a sample.

[0029] Triacetin was used as the sample for detection. The principle of the detection device is as follows: Figure 3As shown, the surface acoustic wave (SAW) sensor is mounted above a liquid triacetin. The liquid is heated to 80°C using a constant-temperature heater, causing the volatilized triacetin vapor to condense and accumulate on the surface of the SAW sensor. The host interface displays the real-time changes in SAW sensor loss. The test lasted approximately 7.7 hours. Figure 11 As shown.

[0030] The accumulation process of condensates on the surface of a surface acoustic wave sensor can be divided into three stages.

[0031] Stage 1: Triacetin vapor condenses on the surface of the surface acoustic wave sensor, forming small droplets. As time increases, the droplets become increasingly dense, such as... Figure 12 As shown. The instrument response varies with the amount of droplet accumulation. Changes in the size and shape of the droplet on the surface acoustic wave sensor surface cause fluctuations in the response curve, resulting in an unsmooth response curve, such as... Figure 13 As shown.

[0032] The second stage: After the boundaries of the small droplets overlap, multiple small droplets merge into one large droplet. This droplet merging behavior causes a sharp peak on the instrument's response curve. For example... Figure 14 As shown, with the increase of condensation, more large droplets appear on the surface of the surface acoustic wave sensor, resulting in multiple spikes on the instrument's response curve. Figure 15 As shown, the rising edge of the peak on the response curve is gentle and the peak value is small. The change in the rising edge of the peak in the second stage is approximately in the range of 0.004~2dB.

[0033] The third stage: As the amount of condensate accumulates, the balance between the surface tension and gravity of the large droplets is broken, and the droplets begin to move, either dripping vertically or sliding along the surface of the surface acoustic wave sensor. Figure 16(a) shows the condensate on the surface acoustic wave sensor before it drips, and Figure 16(b) shows the condensate on the surface acoustic wave sensor after it drips. Droplet movement causes significant changes in loss, resulting in a sharp rise and high peak on the response curve, such as... Figure 17 , 18 As shown in Figure 19.

[0034] In this embodiment, the agglomerates dripped three times in the third stage, with responses of 5.926 dB, 5.510 dB, and 8.006 dB, respectively. The dripping of agglomerates indicates the presence of a risk, and the instrument issues an alarm.

[0035] As can be seen from the above embodiments, this application, in its research on methods for detecting volatile gas condensates, does not limit itself to intuitive thickness detection, but focuses on the formation of condensates and the causes of risks they pose.

[0036] Currently, although existing technologies also use surface acoustic wave technology for detection, they can only detect specific gases and cannot detect the accumulation, fusion, and dripping of volatile condensates in real time and generate real-time feedback.

[0037] This application uses polyethylene glycol-200 and triacetin as volatile agglomerates for detection. Combined with molecular dynamics analysis, it studies the wetting of liquids on different surfaces such as metals and quartz, revealing the agglomerate formation pattern, namely three stages: droplet accumulation, fusion, and droplet falling. The droplet morphology and response curves differ in each stage. The droplet falling stage may pose a safety hazard.

[0038] Building upon this foundation, the applicant, leveraging its strengths, selected surface acoustic wave (SAW) technology, which is sensitive to the weight of objects on a surface, to develop a sensor, and subsequently developed a condensate detection instrument. Through extensive experimentation, response characteristics were extracted, verifying the feasibility of the detection method. By recording the relationship between droplet morphology and response values, the instrument aims to detect different states of condensates.

[0039] This application is based on theoretical research, and designs a sensor suitable for condensate detection and develops an instrument. Response features are extracted through extensive experimentation, which is not obvious to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this application and not to limit it. Although this application has been described in detail with reference to embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solution of this application do not depart from the spirit and scope of the technical solution of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A method for detecting volatile condensates based on surface acoustic wave technology, characterized in that the steps include... include: Step 1: Place the surface acoustic wave sensor at the position to be measured; Step 2: The loss change of the surface acoustic wave sensor measured by the loss measurement module is converted into a digital signal by the high-precision acquisition module, and a response curve is generated; Step 3: The response curve described in Step 2 is analyzed in real time by the data processing module to obtain the accumulation, fusion and dripping state of the test substance.

2. The method for detecting volatile coagulants according to claim 1, characterized in that, The real-time analysis in step 3 includes: a. The non-smooth jitter in the response curve indicates that the vapor of the test object condenses on the surface acoustic wave sensor surface and forms droplets, indicating that it is in an accumulation state. b. The droplets are determined to be in a fusion process by the appearance of multiple peaks on the response curve whose rising edge changes are less than a preset threshold. c. If the response curve shows a steep rising edge and a high peak, it is determined that the droplet is either dripping vertically or sliding along the surface of the surface acoustic wave sensor, and has entered the dripping state.

3. The method for detecting volatile coagulants according to claim 1, characterized in that, The rising edge variation range is from 0.004dB to 2dB.

4. The method for detecting volatile coagulants according to claim 3, characterized in that, When the range of the rising edge exceeds a set threshold, an alarm signal is generated, which is an audible and visual alarm.

5. The method for detecting volatile coagulants according to claim 1, characterized in that, The loss measurement resolution of the loss measurement module is 0.001dB.

6. A detection instrument for implementing the surface acoustic wave (SAW) technology-based volatile condensate detection method of claim 1, used for monitoring the accumulation, fusion, and dripping processes of volatile condensates, characterized in that, include: A surface acoustic wave sensor unit is used to sense the accumulation, fusion, and dripping states of volatile condensates and convert the accumulation, fusion, and dripping states into loop losses. The host unit includes: A loss measurement module, wherein the loss measurement module is used to measure the loss change of the surface acoustic wave sensor; A high-precision acquisition module is used to convert the loss change of the surface acoustic wave sensor measured by the loss measurement module into a digital signal; and a data processing module is used to generate a response curve in real time and detect the accumulation, fusion and dripping state of the test object in real time based on the response curve.

7. The volatile coagulant detection instrument according to claim 6, characterized in that, The aforementioned testing instruments also include, The microcontroller module is used to adjust the input signal frequency of the surface acoustic wave sensor and receive the output signal from the high-precision acquisition module. A coaxial cable is used for long-distance, low-loss transmission of the input and output signals of the surface acoustic wave sensor; The alarm module is used to generate an alarm signal when the change in loss exceeds a set threshold.

8. The volatile coagulant detection instrument according to claim 6, characterized in that, The loss measurement module includes: A signal generator is used to generate radio frequency signals; Filters are used to reduce the energy of high-order harmonics in radio frequency signals; Automatic gain control module, used to amplify signals and improve the dynamic range of the instrument; An amplitude discriminator is used to convert changes in the loss of a surface acoustic wave sensor into a voltage signal.

9. The volatile coagulant detection instrument according to claim 8, characterized in that, The frequency of the radio frequency signal is 30MHz~4000MHz.

10. The volatile coagulant detection instrument according to claim 6, characterized in that, The surface acoustic wave sensor unit is installed separately from the main unit. The surface acoustic wave sensor unit is installed at the location to be measured, and the main unit is installed in a safe area. The two are connected by a coaxial cable.

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