Method and system for real-time monitoring of contaminants in food pipelines using ultrasound

Abstract

A method and system for real-time ultrasonic monitoring of contaminants in food pipelines. In the method, a single ultrasonic probe fixed to the outer wall of the food pipeline generates ultrasonic waves propagating within the pipeline wall based on an excitation pulse signal. The ultrasonic waves are reflected at different media interfaces within the pipeline, forming a reflected signal containing multiple echoes, including at least a first reflected wave signal generated by the pipe wall-contaminant interface or the pipe wall-cleaning fluid interface. The same ultrasonic probe receives the reflected signal and converts it into an electrical signal for output. After conditioning, amplification, and isolation, the electrical signal is acquired as a digital signal via high-speed analog-to-digital conversion and transmitted to a host computer. In the host computer, the energy characteristics of the first reflected wave signal within the target time window are extracted, and its energy characteristic value is calculated. The currently acquired energy characteristic value is compared with a baseline energy value under clean conditions. When the two values ​​are consistent, it is determined that the contaminants in the pipeline have been removed, and the cleaning endpoint has been reached.

Description

Technical Field

[0001] This invention relates to the field of in-situ cleaning and testing technology for food pipelines, and in particular to a method and system for real-time ultrasonic monitoring of contaminants inside food pipelines. Background Technology

[0002] In the production of food, beverages, and dairy products, regular cleaning of processing equipment and pipelines is essential to ensure product quality and hygiene safety. Clean-in-place (CIP) technology is a widely used industrial cleaning method, with a standard cleaning cycle including pre-rinsing, cleaning agent rinsing, intermediate cleaning, disinfection, and final rinsing. The final rinsing stage plays a crucial role in removing deposits and contaminants from pipe walls, making it a critical step in ensuring product quality and hygiene safety. Currently, traditional CIP processes largely rely on fixed time settings or operator experience to determine the cleaning cycle. While this method can guarantee cleaning effectiveness to some extent, it has limitations in actual production. Because the amount of contaminant deposits and their removal effectiveness are influenced by various factors such as raw material properties, process conditions, and pipeline structure, using uniform, fixed cleaning parameters is often difficult to adapt to different operating conditions. This can easily lead to two extreme situations: on the one hand, insufficient cleaning may result in incomplete removal of residues, affecting product quality and increasing food safety risks; on the other hand, to avoid incomplete cleaning, factories often choose to extend cleaning time, increase the flow rate of the cleaning solution, or increase the amount of chemical cleaning agent, resulting in over-cleaning and a significant waste of water, energy, and cleaning agent resources. Current technologies for monitoring cleaning effectiveness mainly include pressure difference detection, turbidity detection, manual sampling, and rapid ATP detection. However, these methods suffer from problems such as poor real-time performance, insufficient detection sensitivity, complex operation, and difficulty in online application in industrial settings, making it difficult to meet the demands of the modern food industry for efficient, accurate, and sustainable cleaning management.

[0003] The information disclosed in the background section is only for enhancing the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This invention provides a method and system for real-time ultrasonic monitoring of contaminants inside food processing pipelines. This system enables real-time, sensitive, and non-destructive monitoring of the removal status of contaminants during in-situ cleaning, providing a basis for accurate determination of the cleaning endpoint. This not only helps avoid over-cleaning or under-cleaning but also significantly improves the cleaning efficiency and reliability of the in-situ cleaning process, reducing the consumption of water, energy, and chemicals required. It solves the problems of existing in-situ cleaning processes, such as the lack of effective real-time monitoring methods, difficulty in accurately determining the cleaning endpoint, and the tendency to over-clean or under-clean.

[0005] A method for real-time ultrasonic monitoring of contaminants inside food pipelines includes:

[0006] A single ultrasonic probe fixed to the outer wall of a food pipe generates ultrasonic waves that propagate within the pipe wall based on an excitation pulse signal;

[0007] The ultrasonic waves are reflected at the interfaces of different media inside the pipe, forming a reflected signal containing multiple echoes, including at least a first reflected wave signal generated by the pipe wall-contaminant interface or the pipe wall-cleaning fluid interface.

[0008] The same ultrasonic probe receives the reflected signal and converts it into an electrical signal for output.

[0009] After conditioning, amplification, and isolation, the electrical signal is acquired as a digital signal by a high-speed analog-to-digital converter and transmitted to the host computer.

[0010] In the host computer, energy features are extracted from the first reflected wave signal within the target time window, and its energy feature value E is calculated:

[0011]

[0012] in, It is the voltage at a certain point in time. and These are the start and end times of the selected time window;

[0013] The currently collected energy characteristic value is compared with the baseline energy value under clean conditions. When the two tend to be consistent, it is determined that the pollutants in the pipeline have been removed, and the cleaning endpoint has been reached.

[0014] In the method for real-time ultrasonic monitoring of contaminants inside food pipelines, the target time window corresponds to the time interval in which the first reflected wave signal of the ultrasonic wave originates from the interface between the inner wall of the pipeline and the contaminant layer or the interface between the inner wall of the pipeline and the cleaning fluid is located.

[0015] In the method for real-time ultrasonic monitoring of contaminants in food pipelines, the target time window is 13.4-14.4 μs.

[0016] In the method for real-time ultrasonic monitoring of contaminants in food pipelines, the reference energy value under clean conditions is obtained by pre-collecting and storing standard reflected signal energy values ​​under known clean pipeline conditions.

[0017] In the method for real-time ultrasonic monitoring of contaminants in food pipelines, the excitation pulse signal is a narrowband pulse signal with a center frequency of 5MHz.

[0018] In the method for real-time ultrasonic monitoring of contaminants inside food pipelines, the ultrasonic probe is made of piezoelectric ceramic material and is attached to the outer surface of the pipeline by a coupling agent and / or an arc-shaped delay block.

[0019] A monitoring system for implementing the method includes:

[0020] A single ultrasonic probe, fixed to the outer wall of a food pipe, to emit and receive ultrasonic signals;

[0021] The signal conditioning module is connected to a single ultrasonic probe via a signal line. The signal conditioning module includes an excitation signal amplification circuit, a receiving signal amplification and filtering circuit, and an isolation circuit between the excitation and receiving signals.

[0022] An ultrasonic signal control and processing unit includes an ultrasonic signal transmitting module, a digital acquisition module, and a host computer analysis module. The ultrasonic signal transmitting module is connected to a single ultrasonic probe, the digital acquisition module is connected to the output of the signal conditioning module, and the host computer analysis module is communicatively connected to the host computer analysis module.

[0023] In the monitoring system described above, the isolation circuit employs a diode series limiting structure or a switching circuit to prevent high-voltage excitation signals from damaging subsequent receiving and acquisition circuits.

[0024] In the monitoring system described above, the ultrasonic signal transmission module includes a microprocessor-controlled integrated signal generator, a general-purpose function generator, or a dedicated pulse excitation circuit to generate an excitation pulse signal with adjustable parameters.

[0025] Compared with existing technologies, this invention has the following advantages: Compared with traditional methods, this method can achieve real-time, online monitoring of the deposition and cleanliness of contaminants inside food pipes. Through characteristic analysis of ultrasonic reflection signals, it is possible to accurately determine whether the inner wall of the pipe is clean without disassembling the pipe, eliminating the need for additional sampling or optical inspection. The proposed ultrasonic monitoring system is simple to use and easy to install, effectively avoiding the over-cleaning problem in traditional in-situ cleaning processes. Attached Figure Description

[0026] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0027] In the attached diagram:

[0028] Figure 1 This is a schematic diagram of an ultrasonic real-time monitoring system for contaminants inside food pipelines.

[0029] Figure 2 This is a schematic diagram of the propagation path of ultrasonic signals in a method for real-time ultrasonic monitoring of contaminants inside food pipes (arrows indicate the direction of sound wave propagation).

[0030] Figure 3 This is a schematic diagram of ultrasonic reflected signals from a contaminated pipe (a) and a clean pipe (b) in a method for real-time ultrasonic monitoring of contaminants in food pipes, as well as windows of 13.4–14.4 μs (c) and 23–24 μs (d).

[0031] Figure 4 This is a schematic diagram showing the changes in energy characteristics at the reflected signal window during the cleaning process of contaminated and clean pipes.

[0032] The present invention will be further explained below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0033] Specific embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0034] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out the invention; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of the invention. The scope of protection of this invention is determined by the appended claims.

[0035] To facilitate understanding of the embodiments of the present invention, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0036] like Figures 1 to 4 As shown, the method for real-time ultrasonic monitoring of contaminants inside food pipelines includes the following steps:

[0037] A single ultrasonic probe fixed to the outer wall of a food pipe generates ultrasonic waves that propagate within the pipe wall based on an excitation pulse signal;

[0038] The ultrasonic waves are reflected at the interfaces of different media inside the pipe, forming a reflected signal containing multiple echoes, including at least a first reflected wave signal generated by the pipe wall-contaminant interface or the pipe wall-cleaning fluid interface.

[0039] The same ultrasonic probe receives the reflected signal and converts it into an electrical signal for output.

[0040] After conditioning, amplification, and isolation, the electrical signal is acquired as a digital signal by a high-speed analog-to-digital converter and transmitted to the host computer.

[0041] In the host computer, energy features are extracted from the first reflected wave signal within the target time window, and its energy feature value E is calculated.

[0042]

[0043] in, It is the voltage at a certain point in time. and These are the start and end times of the selected time window;

[0044] The currently collected energy characteristic value is compared with the baseline energy value under clean conditions. When the two tend to be consistent, it is determined that the pollutants in the pipeline have been removed, and the cleaning endpoint has been reached.

[0045] In a preferred embodiment of the method for real-time ultrasonic monitoring of contaminants inside food pipelines, the target time window corresponds to the time interval in which the first reflected wave signal of the ultrasonic wave originates from the interface between the inner wall of the pipeline and the contaminant layer or the interface between the inner wall of the pipeline and the cleaning fluid is generated.

[0046] In a preferred embodiment of the method for real-time ultrasonic monitoring of contaminants in food pipelines, the target time window is 13.4-14.4 μs.

[0047] In a preferred embodiment of the method for real-time ultrasonic monitoring of contaminants in food pipelines, the reference energy value under clean conditions is obtained by pre-collecting and storing standard reflected signal energy values ​​under known clean pipeline conditions.

[0048] In a preferred embodiment of the method for real-time ultrasonic monitoring of contaminants in food pipelines, the excitation pulse signal is a narrowband pulse signal with a center frequency of 5MHz.

[0049] In a preferred embodiment of the method for real-time ultrasonic monitoring of contaminants inside food pipelines, the ultrasonic probe is made of piezoelectric ceramic material and is attached to the outer surface of the pipeline by a coupling agent and / or an arc-shaped delay block.

[0050] A monitoring system for implementing the method includes:

[0051] A single ultrasonic probe, fixed to the outer wall of a food pipe, to emit and receive ultrasonic signals;

[0052] The signal conditioning module is connected to a single ultrasonic probe via a signal line. The signal conditioning module includes an excitation signal amplification circuit, a receiving signal amplification and filtering circuit, and an isolation circuit between the excitation and receiving signals.

[0053] An ultrasonic signal control and processing unit includes an ultrasonic signal transmitting module, a digital acquisition module, and a host computer analysis module. The ultrasonic signal transmitting module is connected to a single ultrasonic probe, the digital acquisition module is connected to the output of the signal conditioning module, and the host computer analysis module is communicatively connected to the host computer analysis module.

[0054] In a preferred embodiment of the monitoring system, the isolation circuit employs a diode series limiting structure or a switching circuit to prevent high-voltage excitation signals from damaging subsequent receiving and acquisition circuits.

[0055] In a preferred embodiment of the monitoring system, the ultrasonic signal transmitting module includes a microprocessor-controlled integrated signal generator, a general-purpose function generator, or a dedicated pulse excitation circuit to generate an excitation pulse signal with adjustable parameters.

[0056] In one embodiment, a monitoring system includes: an ultrasonic probe, a signal cable, and an ultrasonic signal control and processing unit. The ultrasonic signal control and processing unit mainly comprises three functional modules: an ultrasonic signal transmitting unit, an ultrasonic signal receiving unit, and an ultrasonic signal processing unit.

[0057] In one embodiment, the method includes:

[0058] The ultrasonic signal transmitting module generates an ultrasonic excitation voltage signal; optionally, the excitation voltage signal generated by the ultrasonic signal transmitting unit is a pulse signal. The pulse width, frequency, and energy of the pulse signal are adjustable to adapt to the acoustic characteristics of different pipe materials and thicknesses. The excitation signal frequency is preferably a narrowband pulse of 80MHz. Optionally, the excitation signal is generated by an integrated signal control module with a microprocessor as its core; it can also be output by a general-purpose signal generator; it can also be generated by an integrated device with data acquisition and signal output functions; or it can be implemented by a specially designed ultrasonic pulse excitation circuit. The excitation voltage signal is processed by a signal conditioning module before being applied to the transducer module; optionally, the above signal conditioning module consists of three parts: signal amplification, filtering, and excitation-received signal isolation, including isolation, amplification, and filtering of the excitation and received signals.

[0059] An ultrasonic probe transmits ultrasonic signals to the pipe wall. Optionally, the ultrasonic probe is made of ceramic piezoelectric material, used to convert electrical signals into mechanical vibrations to generate ultrasonic waves, and simultaneously receive reflected ultrasonic signals and convert them back into electrical signals for output. The frequency response of the probe is adapted to the center frequency output by the ultrasonic signal transmitting unit. The probe can be fixed to the outer surface of the pipe with adhesive or assembled using a specially designed bracket for stable positioning and adaptation to pipes of different diameters and structures. A delay block structure can be provided at the front of the probe, and its bottom surface can be machined into an arc shape to fit the outer wall of the pipe, thereby improving coupling efficiency. Coupling agent should be applied between the probe and the delay block, and between the delay block and the probe.

[0060] When an ultrasonic signal encounters a contaminant interface, it generates a corresponding reflected wave signal.

[0061] The reflected wave is received by the same ultrasonic probe, processed by the signal conditioning module, and then acquired by the digital acquisition module. The acquired signal is transmitted to the host computer module for analysis and processing. Optionally, the signal conditioning module consists of three parts: signal amplification, filtering, and excitation-received signal isolation, including isolation, amplification, and filtering of the excitation and received signals. Optionally, the digital acquisition module uses the high-speed analog-to-digital converter (ADC) module of the data acquisition card to convert analog electrical signals into digital signals. Optionally, the host computer module analyzes and processes the reflected wave signal, including:

[0062] S51, Detection signal processing;

[0063] S52. Feature extraction of reflected signals;

[0064] S53, Pattern Recognition;

[0065] Optionally, the above signal processing employs windowing. The complete signal is divided into several time windows, and the ultrasonic signal waves reflected from the interface between the contaminant and the pipe wall are extracted for analysis. This processing method allows for flexible adjustment of the time window length and position according to specific needs.

[0066] Optionally, the above-mentioned reflected signal feature extraction is used for continuous monitoring of signal energy. Signal energy ( It can be calculated by integrating the square of the echo voltage within a selected time window:

[0067]

[0068] in, It is the voltage at a certain point in time. and These are the start and end times of the selected time window.

[0069] Optionally, reflection signal pattern recognition includes using machine learning methods such as artificial neural networks and support vector machines to classify and identify the energy characteristics of reflected wave signals to determine whether there are pollutants in the pipeline.

[0070] In one embodiment, to verify the monitoring effect of the ultrasonic online monitoring system described in this invention during the in-situ cleaning process, a complete experimental setup simulating in-situ cleaning was constructed. For example... Figure 1 As shown, the device consists of sanitary stainless steel pipes, valves, a circulating pump, a water tank, and a temperature probe. The flow rate of the cleaning fluid is controlled by adjusting the pump power, and the temperature probe ensures that the temperature remains constant during the in-situ cleaning experiment. Tomato sauce was used as the contaminant to be cleaned from the pipes, and water was used as the cleaning fluid. The entire experimental setup comprises an in-situ cleaning experimental apparatus, an ultrasonic probe, an ultrasonic excitation and receiving isolation circuit, a power amplifier, an oscilloscope, a DC power supply, a data acquisition card, and a computer for operation.

[0071] The experimental procedure is further explained below. The ultrasonic signal transmitting module generates an ultrasonic excitation voltage signal; specifically, the excitation voltage signal is generated by a signal generator, outputting a single-tone pulse voltage signal that directly acts on the 5MHz ultrasonic probe.

[0072] The excitation voltage signal is processed by the signal conditioning module before being applied to the transducer module. Specifically, the signal conditioning module uses a power amplifier and an excitation receiving isolation circuit. The power amplifier is used to amplify the voltage signal output from the data acquisition card, and the excitation receiving circuit uses a diode series limiting circuit.

[0073] The ultrasonic probe generates ultrasonic signals towards the pipe wall; specifically, the ultrasonic probe uses a piezoelectric transducer to convert the excitation voltage signal into an ultrasonic vibration signal, which is then used to transmit ultrasonic signals towards the pipe wall.

[0074] When an ultrasonic signal encounters a contaminant interface, it generates a corresponding reflected wave signal; specifically, such as... Figure 3 As shown, the ultrasonic signal generated by the ultrasonic probe propagates within the pipe wall, producing different reflected waves as it passes through different interfaces. The ultrasonic wave emitted by the probe, after passing through the pipe wall via a delay band, propagates radially into the internal medium of the pipe. When the sound wave propagates at different medium interfaces (such as pipe wall and contaminant layer, or contaminant layer and fluid medium), some sound energy is emitted and projected, the proportion depending on the acoustic impedance difference between the media on both sides of the interface. Acoustic impedance is mainly determined by the density and compressibility of the medium. When the acoustic impedance difference between adjacent media is large, the amplitude of the reflected signal is significantly enhanced; when the acoustic impedance matching is good, the reflected signal is relatively weak. In this device, the ultrasonic probe receives and records the echo signals reflected from different interfaces. As the cleaning process progresses, the contaminant layer is gradually removed, and the interface in some areas transitions from "pipe wall-contaminant layer" to "pipe wall-cleaning fluid" interface. At this time, because the difference in acoustic impedance between the contaminant layer material and the inner wall of the pipe is smaller than the difference in acoustic impedance between the cleaning fluid and the inner wall of the pipe, the amplitude of the reflected signal from the interface between the inner wall of the pipe and the contaminant layer will increase significantly.

[0075] The reflected waves are received by the same ultrasonic probe, processed by the signal conditioning module, and then acquired by the digital acquisition module. The acquired signals are transmitted to the host computer module for analysis and processing. Specifically, since the reflected wave signals are received by the same ultrasonic probe, all signals passing through the ultrasonic probe need to be processed by isolation circuits to prevent mutual interference. Specifically, the signal acquisition module uses a high-speed analog-to-digital converter (ADC) module to acquire the reflected wave signals, and the host computer analysis module uses an oscilloscope to display the final results.

[0076] Figure 3 The ultrasonic reflection signals of the pipeline in both clean and contaminated states are presented. In the echo signals, each peak corresponds to the reflection of ultrasonic waves at different interfaces, with the second and fourth peaks representing the first and second reflection signals at the interface between the pipeline inner wall and the contaminated layer, respectively. Comparing these two peaks reveals that the amplitude difference of the first reflection wave between the contaminated and cleaned pipeline states is significantly greater than the amplitude difference of the second reflection wave across different pipeline states. Based on this, the first reflection window (13.4–14.4 μs) is selected as the target window for subsequent signal feature analysis in this method.

[0077] exist Figure 4The experiment demonstrates the changes in energy characteristics at the reflected signal window during the cleaning process of contaminated and clean pipelines. For clean pipelines, the energy characteristics of the ultrasonic echo signal remain essentially constant within a specific range. However, for pipelines containing contaminants, the energy characteristic value of the echo signal is significantly lower than that of the contaminated pipeline. As the cleaning process progresses, i.e., as the contaminants are removed, the energy characteristic value of the echo signal from the contaminated pipeline gradually approaches that of the clean pipeline. When the energy characteristic values ​​of the echo signals from both pipelines are the same, it can be determined that the contaminants in the contaminated pipeline have been completely removed, and the cleaning endpoint has been reached. Therefore, the experiment proves that it is feasible to use an online ultrasonic monitoring system to monitor whether a pipeline has been cleaned.

[0078] The ultrasonic online monitoring method for food pipelines provided by this invention can monitor the presence and removal status of contaminants inside the pipeline in real time and accurately, thereby determining whether the pipeline has reached the cleanliness standard. Throughout the cleaning process, ultrasonic signals can be recorded and processed in real time. This allows for real-time assessment of changes in the contaminant layer during cleaning, thus determining whether the cleaning endpoint has been reached. This effectively avoids over-cleaning or under-cleaning, thereby saving resources such as water, electricity, and cleaning agents, and reducing cleaning costs. Furthermore, due to the use of a single-probe reflective ultrasonic design, the device can operate stably in enclosed, opaque pipelines and high-flow-rate environments, making it widely applicable and meeting the industrial production conditions of food, dairy products, and beverages. In addition, by analyzing the energy characteristic values ​​of the primary reflection signal, this invention provides stable and reliable signal processing with strong noise resistance, accurately determining the pipeline cleanliness status in complex fluid environments. Therefore, the in-situ cleaning system can rationally control cleaning time and parameters based on monitoring results, improving cleaning efficiency, ensuring pipeline hygiene and product quality, and reducing food safety risks.

[0079] This invention's single-probe reflective ultrasonic monitoring structure uses a single ultrasonic sensor to simultaneously transmit and receive ultrasonic waves, eliminating the need for traditional transmission-type dual-probe arrangements. This design is particularly suitable for cleaning and monitoring opaque metal pipes in the food industry, enabling real-time monitoring without damaging the pipes or requiring openings, greatly improving the system's industrial applicability and operability. This invention proposes a method based on the energy characteristics of reflected ultrasonic signals to monitor whether contaminants within the pipe have been removed during the cleaning process, allowing for real-time monitoring of the cleaning endpoint in situ. This invention employs a non-invasive, industrially deployable structural design. The ultrasonic monitoring system can be easily and directly installed on the outer wall of existing factory pipes without affecting the sealing and fluid characteristics of the production system. The assembly of this device requires no modification to existing equipment, demonstrating significant promotional value and application prospects.

[0080] Furthermore, this invention employs a single-probe reflective ultrasonic detection structure combined with interface reflection signal energy characteristic analysis to achieve non-invasive, real-time online monitoring of the removal status of contaminants inside food pipelines. This technical solution precisely captures changes in the reflection behavior of ultrasonic waves at the "pipe wall-medium" interface, transforming the physical cleaning state into quantifiable and identifiable electrical signal characteristics, thus overcoming the limitations of traditional cleaning endpoint determination methods, which are often delayed, subjective, or highly destructive.

[0081] Specifically, when an ultrasonic probe emits a pulse signal into the pipe wall, the sound wave propagates radially and is reflected at the interface of media with different acoustic impedances. When contaminants (such as protein deposits, fat residues, or organic matter like tomato sauce) are present in the pipe, the acoustic impedance difference between the contaminants and the stainless steel pipe wall is small, resulting in a low acoustic energy reflection coefficient at the "pipe wall-contaminant" interface and weak echo signal energy. However, as the cleaning process progresses, the contaminants are gradually removed, and this interface gradually transforms into a "pipe wall-cleaning fluid (such as water)" interface. Due to the significantly greater acoustic impedance difference between water and metal, the reflection coefficient increases dramatically, thus significantly enhancing the energy of the first reflected wave returning from this interface. This physical mechanism allows the energy change of the echo signal to directly reflect the thickness and coverage of the contaminant layer, providing a highly sensitive detection basis for the dynamic monitoring of the cleaning process.

[0082] Furthermore, this invention focuses on extracting the energy characteristics of the first interface reflection wave (rather than multiple echoes or propagation time), effectively avoiding measurement drift caused by pipe thickness fluctuations, temperature changes, or fluid disturbances. By setting a specific time window (e.g., 13.4-14.4 μs) to lock onto the target reflection signal and calculating its voltage square integral energy value, stable and noise-resistant monitoring of the key interface state is achieved. This method does not rely on complex waveform recognition or modeling, is computationally simple, and has a rapid response, making it suitable for embedding into industrial control systems for real-time feedback.

[0083] Furthermore, the adoption of a single-probe integrated transceiver design is another key innovation of this invention. Compared to the traditional transmission-type dual-probe layout, this structure eliminates the need for symmetrical sensor installation on both sides of the pipeline, avoiding problems such as limited installation space and difficulty in alignment, making it particularly suitable for densely arranged food processing pipelines. Simultaneously, the probe is attached to the outer wall of the pipeline via a delay block and coupling agent, forming a completely non-invasive monitoring system that does not damage the pipeline's seal, does not affect fluid flow characteristics, and does not introduce contamination risks, meeting the stringent hygiene standards of the food industry (such as FDA and EHEDG requirements). Combined with the excitation-receiver isolation circuit (such as diode limiting or switch protection) in the signal conditioning module, the system can operate stably under conditions of high-voltage excitation and weak echo signals, preventing transmitted pulses from interfering with the receiving channel and ensuring the accuracy of data acquisition. Finally, through trend analysis of the energy curve by the host computer, the system can automatically identify the plateau period of the cleaning process—that is, when the current echo energy approaches the pre-calibrated clean pipeline reference value, the system determines that cleaning is complete and triggers a cleaning process termination command.

[0084] Although embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and instructive, and not restrictive. Those skilled in the art can make many other forms based on the guidance of this specification and without departing from the scope of protection of the claims of the present invention, and all of these are within the scope of protection of the present invention.

Claims

1. A method of real-time monitoring of contaminants in a food pipeline using ultrasound, characterized in that, Includes the following steps: A single ultrasonic probe fixed to the outer wall of a food pipe generates ultrasonic waves that propagate within the pipe wall based on an excitation pulse signal; The ultrasonic waves are reflected at the interfaces of different media inside the pipe, forming a reflected signal containing multiple echoes, including at least a first reflected wave signal generated by the pipe wall-contaminant interface or the pipe wall-cleaning fluid interface. The same ultrasonic probe receives the reflected signal and converts it into an electrical signal for output. After conditioning, amplification, and isolation, the electrical signal is acquired as a digital signal by a high-speed analog-to-digital converter and transmitted to the host computer. In the host computer, energy features are extracted from the first reflected wave signal within the target time window, and its energy feature value E is calculated: ； wherein, is the voltage at a certain point in time, and is the start and end time of the selected time window; The currently collected energy characteristic value is compared with the baseline energy value under clean conditions. When the two tend to be consistent, it is determined that the pollutants in the pipeline have been removed, and the cleaning endpoint has been reached.

2. The method for real-time ultrasonic monitoring of contaminants in food pipelines according to claim 1, characterized in that, Preferably, the target time window corresponds to the time interval in which the first reflected wave signal of the ultrasonic wave is generated at the interface between the inner wall of the pipe and the contaminant layer or the interface between the inner wall of the pipe and the cleaning fluid.

3. The method for real-time ultrasonic monitoring of contaminants in food pipelines according to claim 1, characterized in that, The target time window is 13.4-14.4 μs.

4. The method for real-time ultrasonic monitoring of contaminants in food pipelines according to claim 1, characterized in that, The reference energy value under clean conditions is obtained by pre-collecting and storing standard reflected signal energy values ​​under known clean pipeline conditions.

5. The method for real-time ultrasonic monitoring of contaminants in food pipelines according to claim 1, characterized in that, The excitation pulse signal is a narrowband pulse signal with a center frequency of 5MHz.

6. The method for real-time ultrasonic monitoring of contaminants in food pipelines according to claim 1, characterized in that, The ultrasonic probe is made of piezoelectric ceramic material and is attached to the outer surface of the pipe by a coupling agent and / or an arc-shaped delay block.

7. A monitoring system implementing the method of any one of claims 1-6, characterized in that, It includes: A single ultrasonic probe, fixed to the outer wall of a food pipe, to emit and receive ultrasonic signals; The signal conditioning module is connected to a single ultrasonic probe via a signal line. The signal conditioning module includes an excitation signal amplification circuit, a receiving signal amplification and filtering circuit, and an isolation circuit between the excitation and receiving signals. An ultrasonic signal control and processing unit includes an ultrasonic signal transmitting module, a digital acquisition module, and a host computer analysis module. The ultrasonic signal transmitting module is connected to a single ultrasonic probe, the digital acquisition module is connected to the output of the signal conditioning module, and the host computer analysis module is communicatively connected to the host computer analysis module.

8. The monitoring system according to claim 7, characterized in that, The isolation circuit employs a diode series limiting structure or a switching circuit to prevent high-voltage excitation signals from damaging subsequent receiving and acquisition circuits.

9. The monitoring system according to claim 7, characterized in that, The ultrasonic signal transmission module includes a microprocessor-controlled integrated signal generator, a general-purpose function generator, or a dedicated pulse excitation circuit to generate excitation pulse signals with adjustable parameters.

Images