A cleaning agent concentration analysis system based on pulse harmonic detection

Abstract

The application discloses a cleaning agent concentration analysis system based on pulse harmonic detection and relates to the technical field of electronic manufacturing cleaning, which comprises a four-way flow cell assembly, a sensor probe, a connecting fastener, a pulse emission unit, a pulse receiving unit, a signal processing module, a sensor power supply module and a display and control terminal, wherein the four-way flow cell assembly is installed on a transmission pipeline of a cleaning device and is used for transmitting a measured cleaning agent; the pulse emission unit is installed at a sensing end of the sensor probe; the pulse receiving unit is used for receiving an output response signal and performing preamplification, impedance matching and preliminary filtering on the response signal; and the signal processing module is installed inside the sensor probe.

Description

Technical Field

[0001] This invention belongs to the field of cleaning technology in electronic manufacturing, and specifically relates to a cleaning agent concentration analysis system based on pulse harmonic detection. Background Technology

[0002] In the electronics manufacturing process, circuit board cleaning is a crucial step. The concentration of the cleaning agent directly affects the cleaning effect and the quality of the circuit board. Traditional online concentration detection methods typically include the density method and the refractive index method. The density method indirectly estimates the concentration by measuring the density of the cleaning agent solution. In some simple systems, when the cleaning agent has a single component and its density change after mixing with the solvent is regular, this method has certain applications. For example, for some water-based cleaning agents containing only a small amount of additives, the approximate concentration can be obtained from the density value by referring to tables or empirical formulas within a certain temperature range. However, for cleaning agents with complex formulations, especially systems containing multiple surfactants, detergents, corrosion inhibitors, and other components, the contributions of each component to the density are intertwined, making it difficult to establish a simple density-concentration relationship. Moreover, temperature changes have a significant impact on density. In actual production processes, the temperature of the cleaning solution often fluctuates greatly, which significantly reduces the accuracy of calculating the concentration solely by the density method. In addition, if solid particles are suspended in the cleaning solution during the cleaning process, it will also interfere with the density measurement, leading to deviations in the results. The refractive index method is based on the property that cleaning agent solutions of different concentrations have different refractive indices. In some clear and transparent cleaning agent solutions with relatively simple compositions, such as pure organic solvents, the concentration can be determined by accurately measuring the refractive index. This is usually done using instruments such as an Abbe refractometer, where light is incident from the air into the cleaning agent solution, the refractive index is calculated based on the angle of the reflected light, and the corresponding concentration value is obtained according to a pre-plotted standard curve. However, most industrial cleaning agents are complex mixtures that may contain various organic and inorganic substances, as well as emulsifiers. The presence of these components can cause the cleaning agent to appear milky, cloudy, or colored, severely affecting the propagation path of light and making refractive index measurement difficult or even impossible. In addition, even for cleaning agents with a clear appearance, the large differences in the refractive indices of different components and the complex interactions between them make it difficult to construct a universal refractive index-concentration model. Therefore, the refractive index method is greatly limited in practical applications. In summary, both density and refractive index methods are affected by the complex composition of cleaning agents when performing online concentration detection, which reduces the efficiency of online detection, hinders closed-loop control and timely replenishment in the production process, and results in poor intelligence. Summary of the Invention

[0003] The purpose of this invention is to provide a cleaning agent concentration analysis system based on pulse harmonic detection. This system utilizes the harmonic phenomenon generated when a pulse signal propagates in the cleaning agent to perform concentration analysis. It is unaffected by the complex composition of the cleaning agent, improves detection efficiency, meets the needs of intelligent cleaning process management, and solves the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A cleaning agent concentration analysis system based on pulse harmonic detection includes: a four-way flow cell assembly, installed on the transmission pipeline of the cleaning equipment, for transmitting the cleaning agent to be tested; The sensor probe, installed at one end of the four-way flow cell assembly, is used to transmit pulse excitation signals into the cleaning agent to be tested and receive response signals. Connecting fasteners are installed at the connection between the four-way flow cell assembly and the sensor probe to secure the four-way flow cell assembly and the sensor probe. The pulse transmitting unit, installed at the sensing end of the sensor probe, is used to generate a pulse excitation signal with a preset frequency range, amplitude, and pulse width, and to transmit the pulse excitation signal. The pulse receiving unit, installed at the sensing end of the sensor probe, is used to receive the output response signal and perform pre-amplification, impedance matching, and preliminary filtering on the response signal. The signal processing module, installed inside the sensor probe, is used to process the electrical signal output by the pulse receiving unit and calculate the cleaning agent concentration. A sensor power supply module is installed inside the sensor probe. The sensor power supply module is electrically connected to the pulse transmitting unit and the pulse receiving unit respectively, and is used to provide a stable working power supply. The display and control terminal is electrically connected to the sensor probe and is used to input control parameters, output data signals, control signals, alarm signals, acquired detection signals, and display parameter information.

[0005] Preferably, the sensor probe includes a probe housing, the pulse receiving unit and the pulse transmitting unit are fixed side by side at one end of the probe housing, and the pulse transmitting unit is provided with a transmitting electrode, the pulse receiving unit is provided with a receiving electrode, and the transmitting electrode and the pulse transmitting unit are connected and fixed together by an insulating isolator.

[0006] Preferably, the probe housing has a signal output terminal inside for transmitting signals to the signal processing module. The signal processing module and the sensor power supply module are both fixed inside the probe housing, and the other end of the probe housing is threaded with a cover.

[0007] Preferably, the outer wall of the probe housing is provided with an external thread section for connecting with the four-way flow cell assembly, and a sealing ring is installed at the connection between the probe housing and the four-way flow cell assembly.

[0008] Preferably, the sealing ring is fitted onto the outer wall of the probe housing, and the sealing ring is one of nitrile rubber ring, fluorosilicone rubber ring, EPDM rubber ring, polyurethane rubber ring, and perfluoroether rubber ring.

[0009] Preferably, the sensor probe further includes a temperature detection element for synchronously acquiring the temperature of the cleaning agent to be tested. The temperature detection element is mounted on an insulating isolator between the receiving electrode and the transmitting electrode, and the temperature detection element is located at the end edge of the probe housing.

[0010] Preferably, the signal processing module includes: a signal conditioning submodule, used to perform noise reduction, filtering, baseline correction, and gain adjustment on the acquired raw signal; The analog-to-digital converter submodule is used to convert analog signals into digital signals; The spectrum analysis submodule uses analysis algorithms to extract the fundamental and higher harmonic components. The analysis algorithms include one or more of the following: fast Fourier transform, wavelet analysis, short-time Fourier transform, and phase-locked analysis. The feature extraction submodule is used to extract one or more of the following feature parameters: harmonic amplitude, harmonic phase, harmonic energy ratio, frequency band distribution characteristics, time-domain attenuation characteristics, and waveform distortion characteristics. The concentration calculation submodule is used to convert characteristic parameters into cleaning agent concentration values ​​based on a pre-established concentration calibration model. The data storage submodule is used to store historical test data, calibration parameters, alarm thresholds, and model parameters corresponding to different cleaning agent formulations.

[0011] Preferably, it also includes an automatic calibration module installed inside the sensor probe, which is electrically connected to the signal processing module and is used to periodically call standard concentration sample solutions or standard parameters to perform zero-point calibration and range calibration on the signal processing module.

[0012] Preferably, the pulse transmitting unit includes: a pulse generator for generating a pulse excitation signal; The driver amplifier is connected to the output of the pulse generator and is used to amplify the generated pulse excitation signal. The parameter adjustment circuit is connected to the output of the driver amplifier and is used to adjust and control the pulse frequency, pulse width, duty cycle and emission intensity.

[0013] Preferably, it also includes an alarm module integrated into the display and control terminal, which issues an audible and visual alarm and outputs an interlock control signal when the detected concentration exceeds the set upper or lower limit.

[0014] The cleaning agent concentration analysis system based on pulse harmonic detection proposed in this invention has the following advantages compared with the prior art: 1. This invention connects to the transmission pipeline of the cleaning equipment through a four-way flow pool assembly, and works with a sensor probe to realize the transmission of pulse excitation signals and the acquisition of response signals. Through the coordinated work of the pulse transmission unit, pulse receiving unit, signal processing module, sensor power supply module and display and terminal, the concentration analysis is performed by utilizing the harmonic characteristics generated by the propagation of the pulse signal in the cleaning agent. This fundamentally avoids the measurement deviation caused by complex components, temperature fluctuations, liquid color and turbidity, and achieves the effect of online and real-time detection throughout the process, improving detection efficiency and meeting the needs of intelligent cleaning process management. 2. This invention mounts the pulse transmitting unit, pulse receiving unit, signal processing module, and sensor power supply module on the sensor probe, resulting in a compact structure, convenient installation, and low maintenance cost. It is suitable for various industrial scenarios such as electronic manufacturing, precision hardware, and semiconductor cleaning. 3. The present invention can be installed in the circulating return pipeline, replenishment pipeline, main process tank bypass or online detection branch of the cleaning equipment through the four-way flow pool component. It can be flexibly installed according to the needs of online continuous detection. With the use of connecting fasteners, the convenience of installation is improved. 4. This invention links the sensor probe with the display and control terminal, supporting parameter input, signal acquisition, data display and control output, providing a hardware foundation for intelligent cleaning process management and improving the overall level of intelligence in detection and production. Attached Figure Description

[0015] Figure 1 A schematic diagram of the exploded structure according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of the exploded structure of a sensor probe according to an embodiment of the present invention is shown; Figure 3 A signal processing flowchart according to an embodiment of the present invention is shown; Figure 4 A structural block diagram of a signal processing module according to an embodiment of the present invention is shown; In the diagram: 101, Four-way flow cell assembly; 102, Connecting fastener; 103, Sealing ring; 104, Sensor probe; 105, Sensor power supply module; 106, Pulse transmitting unit; 107, Pulse receiving unit; 108, Signal processing module; 109, Display and control terminal; 201. Probe housing; 202. Transmitting electrode; 203. Receiving electrode; 204. Insulating isolation component; 205. Signal lead-out terminal; 206. Temperature detection element; 207. Cover. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The specific embodiments described herein are merely used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] This invention provides, for example Figure 1-4 The cleaning agent concentration analysis system based on pulse harmonic detection, as shown, includes a four-way flow cell assembly 101, a sensor probe 104, a connecting fastener 102, a pulse transmitting unit 106, a pulse receiving unit 107, a signal processing module 108, a sensor power supply module 105, and a display and control terminal 109. The four-way flow cell assembly 101 is installed on the transmission pipeline of the cleaning equipment for transmitting the cleaning agent to be tested. The sensor probe 104 is installed at one end of the four-way flow cell assembly 101 for transmitting pulse excitation signals into the cleaning agent to be tested and receiving response signals. The connecting fastener 102 is installed at the connection between the four-way flow cell assembly 101 and the sensor probe 104 for fixing the four-way flow cell assembly 101 and the sensor probe 104. The pulse transmitting unit 106 is installed at the sensing end of the sensor probe 104 for generating a preset frequency... The sensor probe 104 receives and transmits pulse excitation signals with a specified frequency range, amplitude, and pulse width. A pulse receiving unit 107 is installed at the sensing end of the sensor probe 104 to receive the output response signal and perform pre-amplification, impedance matching, and preliminary filtering on the response signal. A signal processing module 108 is installed inside the sensor probe 104 to process the electrical signal output by the pulse receiving unit 107 and calculate the cleaning agent concentration. A sensor power supply module 105 is installed inside the sensor probe 104 and is electrically connected to both the pulse transmitting unit 106 and the pulse receiving unit 107 to provide a stable power supply. A display and control terminal 109 is electrically connected to the sensor probe 104 and is used to input control parameters, output data signals, control signals, alarm signals, acquired detection signals, and display parameter information.

[0018] The four-way flow tank assembly 101 connects to the transmission pipeline of the cleaning equipment. In conjunction with the sensor probe 104, it realizes the transmission of pulse excitation signals and the acquisition of response signals. Through the coordinated work of the pulse transmission unit 106, pulse receiving unit 107, signal processing module 108, sensor power supply module 105, and display and terminal, the concentration analysis is carried out by utilizing the harmonic characteristics generated by the propagation of the pulse signal in the cleaning agent. This fundamentally avoids the measurement deviation caused by complex components, temperature fluctuations, liquid color and turbidity, and achieves the effect of online and real-time detection throughout the process, improving detection efficiency and meeting the needs of intelligent cleaning process management.

[0019] Furthermore, such as Figure 1 As shown, the four-way flow cell assembly 101 is a four-way through-cavity structure, made entirely of corrosion-resistant metal material, preferably 316L stainless steel. It has two fluid inlets at the top and bottom, and two functional interfaces at the left and right. The top and bottom ends are fluid channel interfaces, serving as the inlet and outlet of the cleaning agent, respectively. One end of the left and right ends is used to install the sensor probe 104, and the other end can be fitted with a blind plate or sight glass to achieve sealing or observation. The four-way flow cell assembly 101 is directly connected to the circulating return pipeline, replenishment pipeline, main process tank bypass, or online detection branch of the cleaning equipment through flanges, quick-connects, or threaded interfaces, so that the cleaning agent to be tested flows continuously through the cavity, forming a stable and undisturbed detection flow field, providing a standardized detection environment for the sensor probe 104.

[0020] like Figure 1 As shown, the connecting fastener 102 adopts one of the following structures: quick-release clamp, spring clamp, or spiral clamp. The main body of the connecting fastener 102 is an open clamp shape, equipped with a locking handle, bolt, or buckle mechanism. The material of the connecting fastener 102 is 304 stainless steel, 316L stainless steel, 2205 duplex stainless steel, titanium alloy, or other metal materials that can withstand material corrosion, temperature, and pressure. In this solution, the quick-release clamp of 316L stainless steel is preferred. During installation, the fastener is placed on the outside of the mating end of the four-way flow cell assembly 101 and the sensor probe 104. By tightening the bolt, pressing the handle, or fastening the buckle, a radial clamping force is generated, so that the mating surfaces of the two are tightly fitted, and the intermediate sealing ring 103 is pressed to achieve sealing and mechanical fixation. The whole system has the characteristics of quick assembly and disassembly, reliable sealing, vibration resistance, and corrosion resistance, and can quickly complete the coaxial positioning and locking of the probe and the flow cell.

[0021] like Figure 2As shown, the sensor probe 104 includes a probe housing 201. The pulse receiving unit 107 and the pulse transmitting unit 106 are fixed side by side at one end of the probe housing 201. The pulse transmitting unit 106 is provided with a transmitting electrode 202, and the pulse receiving unit 107 is provided with a receiving electrode 203. The transmitting electrode 202 and the pulse transmitting unit 106, as well as the receiving electrode 203 and the pulse receiving unit 107, are connected and fixed by an insulating isolator 204. The pulse transmitting unit 106 and the pulse receiving unit 107 are arranged side by side, and the transmitting electrode 202 and the receiving electrode 203 are arranged in a counter-alternating manner to improve the ability to distinguish harmonic propagation characteristics. The pulse signal is coupled and transmitted to the cleaning agent through the transmitting electrode 202, and the harmonic response signal is collected through the receiving electrode 203. The insulating isolator 204 realizes electrical insulation between the electrode and the probe housing 201, blocking leakage and signal crosstalk paths, so that the sensor probe 104 can work stably in the corrosive cleaning agent environment for a long time, extending its service life. The probe housing 201 has a signal output terminal 205 inside for transmitting signals to the signal processing module 108. The response signal collected by the electrode is stably transmitted to the signal processing module 108. The overall structure is compact, reducing external wiring and external electromagnetic interference. The signal processing module 108 and the sensor power supply module 105 are both fixed inside the probe housing 201. The other end of the probe housing 201 is threaded with a cover 207. The cover 207 and the probe housing 201 form a closed protective structure, which is suitable for liquid detection environment, easy to install and maintain, and greatly improves the system's operational stability and environmental adaptability. The outer wall of the probe housing 201 is provided with an external thread section for connecting with the four-way flow cell assembly 101. A sealing ring 103 is installed at the connection between the probe housing 201 and the four-way flow cell assembly 101. The sealing ring 103 is sleeved on the outer wall of the probe housing 201. The connecting fastener 102 has an installation groove for installing the sealing ring 103. The sealing ring 103 is one of nitrile rubber ring, fluorosilicone rubber ring, EPDM rubber ring, polyurethane rubber ring and perfluoroether rubber ring. The sealing ring 103 improves the sealing performance of the connection between the four-way flow cell assembly 101 and the sensor probe 104, reduces material leakage in the pipe, and the sealing ring 103 is resistant to cleaning agent corrosion, high and low temperature resistance, and aging resistance. It does not fail after long-term use, ensuring continuous and stable sealing at the connection position and is suitable for harsh working conditions of various industrial cleaning agents. The sensor probe 104 also includes a temperature detection element 206 for synchronously acquiring the temperature of the cleaning agent to be tested. The temperature detection element 206 is installed on the insulating isolator 204 between the receiving electrode 203 and the transmitting electrode 202, and the temperature detection element 206 is located at the end edge of the probe housing 201. The temperature detection element 206 is a PT100 platinum resistance thermometer or an NTC thermistor, preferably a miniature PT100 platinum resistance thermometer. The temperature detection element 206 acquires the temperature data of the cleaning agent to be tested in real time, and the temperature parameters are synchronously sent to the signal processing module 108 to participate in concentration calculation compensation, eliminating the influence of temperature changes on harmonic propagation and concentration calculation, further improving the accuracy and stability of the detection results, and broadening the applicable temperature range of the system.

[0022] The pulse transmitting unit 106 includes a pulse generator, a drive amplifier, and a parameter adjustment circuit. The pulse generator generates a pulse excitation signal; the drive amplifier is connected to the output of the pulse generator and amplifies the generated pulse excitation signal; the parameter adjustment circuit is connected to the output of the drive amplifier and controls the pulse frequency, pulse width, duty cycle, and transmission intensity. The pulse generator can be an AD9833, MAX038, or STM32 microcontroller with built-in timer pulse output; the drive amplifier can be an OPA847, AD844, or THS3091 high-speed broadband operational amplifier. The parameter adjustment circuit consists of a digital potentiometer, a multiplexer, a PWM adjustment unit, and an MCU. The digital potentiometer controls the equivalent resistance value with a digital signal, enabling continuous, precise, and contactless adjustment of the pulse frequency, pulse width, drive gain, and signal amplitude. The multiplexer switches between different frequency levels, different pulse width modes, and different gain levels, allowing the system to... It can quickly adapt to the detection needs of different cleaning agents and different concentration ranges, reduce the occupation of control ports, and improve the flexibility and response speed of parameter adjustment. The PWM adjustment unit outputs a square wave or pulse drive signal with a fixed frequency and adjustable duty cycle according to the parameters set by the MCU. It is used to accurately define the pulse width, repetition frequency, transmission duration and transmission intensity of the pulse excitation signal, and provide a stable and standard timing reference for the pulse transmission unit 106 to ensure that the pulse excitation required for harmonic detection is highly consistent and repeatable. The MCU is used to receive parameter instructions issued by the display and control terminal 109, and to perform parsing, calculation and logic processing. At the same time, it outputs control signals to the digital potentiometer, multiplexer and PWM adjustment unit to coordinate the work of each device. It also collects the operating status of the pulse transmission unit 106 in real time and sends it back to the display terminal to realize parameter display and closed-loop calibration. It also performs real-time monitoring, abnormal protection and stable control of the entire excitation signal output process to ensure that the system works reliably and the detection parameters are accurate. During adjustment and control, the user inputs and confirms the target pulse parameters through the display and control terminal 109. These parameters include pulse frequency, pulse width, duty cycle, and emission intensity. The display and control terminal 109 transmits these settings to the MCU. Upon receiving the parameter command, the MCU writes the digital control quantity into the parameter adjustment circuit via the communication interface. The parameter adjustment circuit, based on the command, changes the resistance value, frequency division coefficient, comparison level, or PWM duty cycle of the internal digital potentiometer, thereby adjusting the oscillation period, trigger timing, and output waveform characteristics of the pulse generator. Simultaneously, it changes the amplification factor and output amplitude of the drive amplifier. The pulse generator... Under the control of the adjustment circuit, a pulse excitation signal that meets the target parameters is generated. After being enhanced in power and driving capability by the drive amplifier, it is coupled to the cleaning agent to be tested through the transmitting electrode 202. During this process, the parameter adjustment circuit and the pulse transmitting unit 106 will transmit the current operating frequency, pulse width, duty cycle, transmission intensity and other status information back to the MCU in real time. After the MCU completes the data processing, it uploads it to the display and control terminal 109 for real-time display, thus forming a complete closed-loop control of parameter setting, command issuance, execution adjustment, signal output and status feedback, ensuring that the pulse excitation signal is output stably and accurately according to the user set value.

[0023] The pulse receiving unit 107 includes a low-noise amplifier, a bandpass filter, and an analog-to-digital converter (ADC) interface. The input of the low-noise amplifier is connected to the receiving electrode 203, the output of the low-noise amplifier is connected to the input of the bandpass filter, and the output of the bandpass filter is connected to the input of the ADC interface, thus realizing cascaded signal processing. The low-noise amplifier can be an AD8253, LTC6244, or OPA333; the bandpass filter can be a MAX7400, UAF42, or an RC active filter network; and the ADC interface can be an ADS1115, ADC128S102, or S... The TM32 has a built-in ADC. During operation, the weak harmonic response signal acquired by the receiving electrode 203 first enters the low-noise amplifier, which amplifies the weak signal with high gain and low noise figure and suppresses background noise. Then, the signal passes through a bandpass filter to filter out power frequency interference, high-frequency noise and non-target frequency band signals, retaining the effective harmonic frequency band. The analog signal is then converted into a digital signal by the analog-to-digital converter interface and sent to the signal processing module 108. Through pre-amplification, narrowband filtering, impedance matching and high-resolution sampling, the signal-to-noise ratio and extraction capability of the weak harmonic signal are improved, ensuring that low-amplitude signals can be stably identified.

[0024] like Figure 3 and Figure 4 As shown, the signal processing module 108 includes a signal conditioning submodule, an analog-to-digital conversion submodule, a spectrum analysis submodule, a feature extraction submodule, a concentration calculation submodule, and a data storage submodule. The signal conditioning submodule is used to perform denoising, filtering, baseline correction, and gain adjustment on the acquired raw signal. The signal conditioning submodule executes the following signal conditioning process: A1. A voltage follower composed of a high-precision operational amplifier and a differential impedance conversion network are used to perform impedance matching on the original signal to avoid signal reflection and attenuation. A2. The least mean square algorithm is used to identify and filter out power frequency interference, electromagnetic noise, high-frequency noise and random noise generated by liquid disturbance in the signal in real time, while retaining the real and effective harmonic response components. A3. Perform a baseline correction process to eliminate the baseline offset caused by temperature drift, circuit bias, and probe contact potential, so that the signal reference returns to near zero. The baseline correction process uses a moving average filtering algorithm or a polynomial fitting algorithm to sample and fit the baseline of the blank segment of the signal without pulse excitation, calculate the baseline offset and generate a real-time correction amount, and pull the offset baseline back to near the ideal zero potential. A4. Automatically or manually adjust the amplification factor according to the signal amplitude to amplify weak harmonic signals to the optimal voltage range suitable for analog-to-digital conversion; the voltage conditioning formula is: , In the formula, The conditioned output voltage, This is the gain coefficient. The input voltage signal is... Baseline compensation voltage; A5. Outputs high-quality analog signals with regular amplitude, low noise, and stable baseline, providing reliable input for subsequent analog-to-digital conversion and spectrum analysis; The analog-to-digital conversion submodule is used to convert analog signals into digital signals. The analog-to-digital conversion submodule uses an analog-to-digital converter to perform time discretization sampling on continuous analog signals at a fixed sampling frequency to obtain a series of instantaneous voltage values. The sampled instantaneous voltage values ​​are then kept fixed to provide a stable level for subsequent quantization. The continuously changing analog voltage values ​​are then divided into discrete level levels according to the minimum resolution, mapping the analog quantity to the closest discrete digital level. The quantized discrete level is then converted into binary digital code, and finally outputs a digital signal corresponding to the analog voltage. The spectrum analysis submodule uses analysis algorithms to extract the fundamental and higher harmonic components. These algorithms include one or more of the following: Fast Fourier Transform (FFT), wavelet analysis, Short-Time Fourier Transform (SFT), and Phase-Locked Analysis (PLA). The formula for the FFT algorithm is as follows: , In the formula, The frequency domain output value represents the complex amplitude and phase corresponding to the k-th frequency point. For the time-domain sampled signal, represents the discrete sampled voltage value at point n, where n is the time-domain sampling point index, k is the frequency-domain frequency point index, N is the total number of sampling points in one frame, and j is the imaginary unit. Pi; The wavelet analysis algorithm formula is: , In the formula, The energy distribution of the signal in the time plane. This represents the original continuous time-domain signal, where t is the time variable, b is the scaling factor corresponding to frequency (a larger b indicates a lower frequency), and c is the translation factor corresponding to the time position. As the energy normalization factor, It is the conjugate function of the mother wavelet; The formula for the short-time Fourier transform algorithm is: , In the formula, The time-frequency domain distribution value, For the time-domain signal to be analyzed, For integration time variable, Let f be the time center position, and f be the frequency variable. For window functions, Let j be the complex exponential basis function, and j be the imaginary unit. Pi; Phase-locked analysis algorithm uses the principle of correlation detection to lock onto the fundamental and higher harmonic components of the same frequency as the excitation signal, thus greatly suppressing noise interference; The algorithm accurately extracts the fundamental amplitude and phase, as well as the amplitude and phase information of the second, third, and other higher harmonics, from the frequency domain data. Specifically, the extraction process involves first performing Fast Fourier Transform, Wavelet Analysis, Short-Time Fourier Transform, or Phase-Locked Analysis on the digital signal after analog-to-digital conversion and windowing preprocessing to convert the time-domain signal into frequency-domain data. Then, the fundamental frequency point corresponding to the system pulse excitation signal is located in the frequency-domain data. Using the fundamental frequency as a reference, the target frequency points corresponding to the second, third, and higher harmonics are determined sequentially. Next, the corresponding complex spectrum values ​​are read at each target frequency point. The amplitudes of the fundamental and each harmonic are calculated, and the phase information of the fundamental and each harmonic is calculated. Finally, the fundamental amplitude, fundamental phase, second harmonic amplitude, second harmonic phase, third harmonic amplitude, and third harmonic phase data are compiled and output.

[0025] The feature extraction submodule is used to extract one or more feature parameters from harmonic amplitude, harmonic phase, harmonic energy ratio, frequency band distribution characteristics, time-domain attenuation characteristics, and waveform distortion characteristics. The feature extraction submodule performs the following feature parameter extraction process: B1. Read the frequency domain data and time domain waveform data output by the spectrum analysis, first extract the harmonic amplitude and harmonic phase, that is, directly read the amplitude and phase values ​​of the fundamental wave and each harmonic at the corresponding frequency point. B2. Calculate the harmonic energy ratio. Sum the squares of the amplitudes of higher harmonics to obtain the total energy of the higher harmonics. Sum the squares of the fundamental frequency amplitude to obtain the fundamental frequency energy. The ratio of the total energy of the higher harmonics to the fundamental frequency energy is used as the harmonic energy ratio. The formula for calculating the harmonic energy ratio is: ,in, Harmonic energy ratio, The total energy of higher harmonics, It is the fundamental wave energy; B3. Extract frequency band distribution features, perform integral calculation on the spectral amplitude within the set target frequency band, obtain the total energy of the corresponding frequency band, and characterize the energy distribution of the signal in different frequency bands; B4. Extract the time-domain decay characteristics. Read the initial amplitude and amplitude at different times from the impulse response waveform, and obtain the time-domain decay time constant by fitting it with the exponential decay model. This constant characterizes the decay rate of the pulse signal in the cleaning agent. The formula for the exponential decay model is: , In the formula, Let be the signal amplitude at time t, representing the voltage amplitude of the impulse response signal at time t; is the initial amplitude, representing the maximum amplitude of the signal at the instant the pulse excitation ends; e is the natural constant, and t is the time variable (calculated from the end of the pulse). The time-domain decay time constant represents the decay rate of the pulse harmonic signal in the cleaning agent; B5. Extract waveform distortion features and obtain the degree of waveform distortion by calculating the difference between the actual waveform and the ideal fundamental waveform, total harmonic distortion, and other indicators. B6. Combine one or more feature parameters extracted from B1 to B5 into a feature vector to complete the extraction and output of all features; The concentration calculation submodule is used to convert characteristic parameters into cleaning agent concentration values ​​based on a pre-established concentration calibration model; The formula for converting cleaning agent concentration values ​​is: In the formula, C is the concentration of the cleaning agent (%). The measured harmonic velocity is (m / s). Let K be the harmonic velocity of the pure solution (m / s), K be the temperature coefficient, and T be the absolute temperature (K). The viscosity coefficient is... Pressure (Pa). For compensation coefficient, These are waveform characteristic parameters; The concentration calibration model was established as follows: Multiple standard sample solutions of different concentrations (1%, 3%, 5%, 7%, 10%, 12%) were prepared using the same type of cleaning agent. Pulse harmonic response data were collected under the same installation conditions. Spectral analysis was performed on the collected data to extract characteristic parameters such as second harmonic amplitude, third harmonic amplitude, total harmonic distortion, and phase shift. A concentration prediction model was then established using multiple regression, table lookup fitting, or machine learning algorithms. The results are shown in Table 1 below. Table 1 Serial Number Concentration rate temperature 10.5 25.1 31.7 36.2 45.2 1 1% 1412.8 1448.2 1465.3 1478.6 1493.5 2 3% 1410.7 1445.3 1462.2 1475.8 1490.6 3 5% 1408.1 1443.2 1460.3 1473.7 1488.5 4 7% 1405.9 1442.4 1457.2 1470.6 1485.4 5 10% 1403.0 1439.3 1454.4 1467.4 1482.2 6 12% 1401.2 1437.2 1452.3 1465.5 1480.1 During use, when changing the type of cleaning agent, simply recalibrate the corresponding sample solution to quickly establish a new model and improve the system's adaptability.

[0026] The data storage submodule is used to store historical test data, calibration parameters, alarm thresholds, and model parameters corresponding to different cleaning agent formulations. The data storage submodule adopts AT24Cxx series EEPROM, W25Qxx series Flash, SD card, and MCU built-in Flash, which can save historical test data, calibration parameters, alarm thresholds and multiple formulation models for a long time, and supports no data loss after power failure and fast reading and retrieval.

[0027] The sensor power supply module 105 includes a voltage regulator circuit, a filter circuit, an overvoltage protection circuit, and an electromagnetic isolation circuit. The voltage regulator circuit consists of LM7805, AMS1117, and LP38798 voltage regulator chips combined with capacitors to stabilize the input voltage at a constant output of 3.3V / 5V. The filter circuit consists of a π-type RC / LC network, electrolytic capacitors, and ceramic capacitors to filter out high and low frequency ripple. The overvoltage protection circuit consists of a Zener diode, a MOSFET, and a fuse to quickly cut off the output when the input voltage exceeds the limit. The electromagnetic isolation circuit consists of a digital isolator ADUM1201 and an isolation power supply module B0505S to achieve ground potential isolation, suppress common-mode interference, and improve the system's anti-interference capability and operational stability. The display and control terminal 109 is one of the following: a combination of PLC (Programmable Logic Controller), SCM (Single-Chip Microcomputer), and touch screen; a programmable logic controller display all-in-one machine; and a single-chip microcomputer device with display control. It is preferably a combination of programmable logic controller and touch screen. It has functions such as parameter input, data display, signal acquisition, control output, alarm linkage, and power management. Through the linkage between the sensor probe 104 and the display and control terminal 109, it supports parameter input, signal acquisition, data display, and control output, providing a hardware foundation for intelligent cleaning process management and improving the overall level of intelligence in detection and production.

[0028] To improve the accuracy of signal processing, this system also includes an automatic calibration module installed inside the sensor probe 104, electrically connected to the signal processing module 108, used to periodically call standard concentration sample solutions or standard parameters to perform zero-point calibration and range calibration on the signal processing module 108; the automatic calibration module performs the following calibration procedure: C1. After calibration is started, the standard concentration sample solution is introduced, or the internally stored standard electrical signal parameters are directly called. Then the pulse emission unit 106 emits a pulse excitation signal according to the conventional detection procedure. C2. The pulse receiving unit 107 collects the harmonic response signal corresponding to the standard sample solution. After signal conditioning, analog-to-digital conversion, spectrum analysis and feature extraction, the standard feature parameters are sent to the concentration calculation submodule. C3. Compare the real-time measured characteristic values ​​with the theoretical characteristic values ​​of the standard concentration to calculate the current zero-point offset and range deviation of the system. C4. Based on the deviation data, the baseline, gain, and calibration model coefficients in the signal processing module 108 are corrected and compensated to complete zero-point correction and range correction. The zero-point correction formula is as follows: In the formula, For the corrected baseline voltage, This is the zero-point drift amount. The zero-point measured baseline voltage; The range calibration formula is: In the formula, To correct the gain value, To set the gain value, This is the theoretical value of the standard sample solution. These are measured values; C5. After calibration is completed, the system automatically saves the latest calibration coefficients and overwrites the original parameters, then exits the calibration process and resumes normal online detection. Regular automatic calibration continuously eliminates detection errors caused by circuit drift, temperature changes, and probe wear, ensuring that the system maintains high precision and stable operation over a long period of time.

[0029] To facilitate interlocking control, this system also includes an alarm module integrated into the display and control terminal 109. When the detected concentration exceeds the set upper or lower limit, an audible and visual alarm is issued and an interlocking control signal is output. The alarm module consists of a signal acquisition unit, a threshold comparison unit, an audible and visual execution unit, and an interlocking control unit. The audible and visual execution unit includes a buzzer and an LED indicator. The alarm module operates continuously in real time during normal detection. The concentration calculation submodule continuously transmits the real-time calculated cleaning agent concentration value to the alarm module. The alarm module first synchronously compares the real-time concentration value with the user-preset upper and lower concentration thresholds. When the real-time concentration exceeds the upper or lower limit, an interlocking control signal is output. When the concentration falls below the lower threshold, the threshold comparison unit immediately outputs an abnormal trigger signal, driving the audible and visual execution unit to activate. This causes the buzzer to sound an alarm and the LED indicator to flash. Simultaneously, the interlock control unit outputs a switch signal or a communication-format interlock control signal, which can be directly connected to an external dosing system, cleaning equipment control system, or host computer to trigger automatic liquid replenishment, equipment shutdown, process reminders, and other linked actions. When the concentration value returns to the threshold range, the alarm module automatically deactivates the audible and visual alarm and resets the interlock signal. This provides real-time monitoring, immediate alarm, and proactive protection against concentration anomalies throughout the process, preventing a decrease in cleaning effectiveness or product quality defects due to concentration deviations from the process range.

[0030] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A cleaning agent concentration analysis system based on pulse harmonic detection, characterized in that: include: The four-way flow tank assembly (101) is installed on the transmission pipeline of the cleaning equipment and is used to transmit the cleaning agent to be tested; A sensor probe (104) is installed at one end of a four-way flow cell assembly (101) for transmitting a pulse excitation signal into the cleaning agent to be tested and receiving a response signal. A fastener (102) is installed at the connection between the four-way flow cell assembly (101) and the sensor probe (104) to fix the four-way flow cell assembly (101) and the sensor probe (104). The pulse transmitting unit (106) is installed at the sensing end of the sensor probe (104) and is used to generate a pulse excitation signal with a preset frequency range, amplitude and pulse width, and to transmit the pulse excitation signal. The pulse receiving unit (107) is installed at the sensing end of the sensor probe (104) to receive the output response signal and perform pre-amplification, impedance matching and preliminary filtering on the response signal; The signal processing module (108) is installed inside the sensor probe (104) and is used to process the electrical signal output by the pulse receiving unit (107) and calculate the cleaning agent concentration. The sensor power supply module (105) is installed inside the sensor probe (104). The sensor power supply module (105) is electrically connected to the pulse transmitting unit (106) and the pulse receiving unit (107) respectively, and is used to provide a stable working power supply. The display and control terminal (109) is electrically connected to the sensor probe (104) and is used to input control parameters, output data signals, control signals, alarm signals, acquired detection signals and display parameter information.

2. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 1, characterized in that: The sensor probe (104) includes a probe housing (201), and the pulse receiving unit (107) and the pulse transmitting unit (106) are fixed side by side at one end of the probe housing (201). The pulse transmitting unit (106) is provided with a transmitting electrode (202), and the pulse receiving unit (107) is provided with a receiving electrode (203). The transmitting electrode (202) and the pulse transmitting unit (106) and the receiving electrode (203) and the pulse receiving unit (107) are connected and fixed by an insulating isolator (204).

3. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 2, characterized in that: The probe housing (201) is provided with a signal output terminal (205) for transmitting signals to the signal processing module (108). The signal processing module (108) and the sensor power supply module (105) are both fixed inside the probe housing (201), and the other end of the probe housing (201) is threaded with a cover (207).

4. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 3, characterized in that: The outer wall of the probe housing (201) is provided with an external thread section for connecting with the four-way flow cell assembly (101), and a sealing ring (103) is installed at the connection between the probe housing (201) and the four-way flow cell assembly (101).

5. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 4, characterized in that: The sealing ring (103) is fitted onto the outer wall of the probe housing (201). The sealing ring (103) is one of nitrile rubber ring, fluorosilicone rubber ring, EPDM rubber ring, polyurethane rubber ring and perfluoroether rubber ring.

6. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 3, characterized in that: The sensor probe (104) also includes a temperature detection element (206) for synchronously acquiring the temperature of the cleaning agent to be tested. The temperature detection element (206) is installed on an insulating isolator (204) between the receiving electrode (203) and the transmitting electrode (202), and the temperature detection element (206) is located at the end edge of the probe housing (201).

7. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 1, characterized in that: The signal processing module (108) includes: a signal conditioning submodule, used to perform noise reduction, filtering, baseline correction and gain adjustment on the acquired raw signal; The analog-to-digital converter submodule is used to convert analog signals into digital signals; The spectrum analysis submodule uses analysis algorithms to extract the fundamental and higher harmonic components. The analysis algorithms include one or more of the following: fast Fourier transform, wavelet analysis, short-time Fourier transform, and phase-locked analysis. The feature extraction submodule is used to extract one or more of the following feature parameters: harmonic amplitude, harmonic phase, harmonic energy ratio, frequency band distribution characteristics, time-domain attenuation characteristics, and waveform distortion characteristics. The concentration calculation submodule is used to convert characteristic parameters into cleaning agent concentration values ​​based on a pre-established concentration calibration model. The data storage submodule is used to store historical test data, calibration parameters, alarm thresholds, and model parameters corresponding to different cleaning agent formulations.

8. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 7, characterized in that: It also includes an automatic calibration module installed inside the sensor probe (104), which is electrically connected to the signal processing module (108) and is used to periodically call standard concentration sample solution or standard parameters to perform zero-point calibration and range calibration on the signal processing module (108).

9. The cleaning agent concentration analysis system based on pulse harmonic detection according to claim 1, characterized in that: The pulse transmitting unit (106) includes: a pulse generator for generating a pulse excitation signal; The driver amplifier is connected to the output of the pulse generator and is used to amplify the generated pulse excitation signal. The parameter adjustment circuit is connected to the output of the driver amplifier and is used to adjust and control the pulse frequency, pulse width, duty cycle and emission intensity.

10. A cleaning agent concentration analysis system based on pulse harmonic detection according to claim 1, characterized in that: It also includes an alarm module integrated in the display and control terminal (109), which issues an audible and visual alarm and outputs an interlock control signal when the detected concentration exceeds the set upper or lower limit.

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