Automatic flow measuring device for small and medium rivers

Abstract

This invention belongs to the field of hydrological and hydraulic measurement, specifically relating to an automatic flow measurement device for small and medium-sized rivers. It includes an inlet pipeline, three sampling branches, a four-way valve, measuring elements, a data acquisition and processing unit, and an output unit. The four-way valve integrates a resonant self-cleaning mechanism. Through a layer of hydrophobic glass microspheres with differentiated thickness and filling rate, and a semi-permeable membrane, local resonance is generated under the drive of piezoelectric ceramics, mechanically peeling away deposits on the inner wall and preventing excessive cavitation from interfering with downstream measuring elements. The three sampling branches simultaneously measure flow data, employing a multi-cycle, multi-sampling, three-way pairwise deviation comparison and statistical filtering algorithm to achieve instantaneous anomaly removal, long-term drift monitoring, and automatic shielding of faulty paths. The device has multi-parameter expansion capabilities, good silt removal effect, and advantages such as low interference, high fault tolerance, low power consumption, and suitability for unattended field operation.

Description

Technical Field

[0001] This invention relates to the field of hydrological and water conservancy measurement technology, specifically to an automatic flow measurement device for small and medium-sized rivers. Background Technology

[0002] Flow monitoring of small and medium-sized rivers is a crucial foundation for water resource management and flood control. Existing technologies, such as multi-point sampling systems, often suffer from complex structures, lack of data cross-verification, and susceptibility to sensor malfunctions. Furthermore, sediment and silt in rivers easily adhere to the inner walls of valves and channels, altering flow distribution ratios and introducing measurement errors. While ultrasonic dredging is effective, its strong cavitation effect releases numerous microbubbles and pressure shock waves into the water. These bubbles and disturbances continuously affect downstream flow velocity sensors (especially electromagnetic and ultrasonic types) and pressure sensors, causing measurement noise and deviations for several minutes or even longer, severely impacting subsequent precise measurements.

[0003] Furthermore, some existing self-cleaning flow measurement devices often use ultrasonic transducers directly attached to the outer or inner wall of the flow channel for cleaning. However, ultrasonic cleaning not only generates strong cavitation effects in the low-frequency range, but also severely interferes with the measurement accuracy of electromagnetic velocity sensors, pressure sensors, and optical water quality sensors even in the mid-to-high frequency range (40~80 kHz), and this interference can last for several minutes to tens of minutes. For automatic flow stations on small and medium-sized rivers that require continuous and high-precision monitoring, such interference is unacceptable. Conventional single-frequency ultrasonic cleaning or mechanical scraping methods are insufficient to completely remove the aforementioned complex deposits and may damage valve sealing surfaces or sensor sensitive elements. Currently, there is no flow measurement device that can simultaneously possess multi-channel data self-calibration and fault tolerance capabilities without generating cavitation interference.

[0004] For example, in the initial conception of this invention, the one-in-three-out characteristic of a four-way valve was used to make the sampling environment of the three sampling branches converge at once, and then the data were compared and screened to obtain more accurate experimental data. However, it was found in the experiment that since the structure of the four-way valve is more complex than that of the three-way valve and the two-way valve, if ultrasonic transducers are added, three ultrasonic transducers must be added to ensure the cleaning effect to guarantee consistency. However, the strong vibrations brought by the three ultrasonic transducers have a significant impact on the sensor, and the impact on the sensor is greater the closer to the four-way valve, which can easily affect the accuracy and lifespan of the sensor.

[0005] Furthermore, during ultrasonic cleaning, the typical frequencies are as follows: Low-frequency cleaning (20kHz-40kHz): effectively removes heavy contaminants; the ultrasonic waves in this frequency band generate large cavitation bubbles, and the energy released when the bubbles collapse is extremely strong, with a very powerful impact. In this invention, it has the greatest impact on the sensor.

[0006] Medium-frequency cleaning (40kHz-80kHz): Relatively gentle; achieving an optimal balance between cleaning power and gentleness. The bubbles are of moderate size and evenly distributed, effectively removing common grease, dust, and particles without damaging ordinary objects. However, in this invention, if the three ultrasonic transducers installed inside the four-way valve are cleaned using medium-frequency cleaning, it will also affect the sensor.

[0007] High-frequency cleaning (80kHz and above): generates a large number of extremely small bubbles, resulting in a very delicate and gentle action. It can penetrate deep into tiny crevices to remove submicron-sized ultrafine particles with almost no damage to delicate surfaces. Therefore, it is not suitable for cleaning sludge deposits that may be more than 7mm thick, as the peeling efficiency is particularly slow, and it is generally only suitable for fine cleaning. Summary of the Invention

[0008] The purpose of this invention is to provide an automatic flow measurement device for small and medium-sized rivers to solve the above-mentioned problems.

[0009] The purpose of this invention is to provide an automatic flow measurement device for small and medium-sized rivers, which can be achieved through the following technical solutions: An automatic flow measurement device for small and medium-sized rivers includes: Water inlet pipeline; There are three sampling branches. The four-way valve includes a valve body, a four-way valve inlet, and three four-way valve outlets with the same flow channel structure and consistent flow resistance. The valve body is provided with an internal water channel that is connected to both the four-way valve inlet and the four-way valve outlet. The three four-way valve outlets are respectively connected to three sampling branches. Measuring elements are used to measure the monitoring data corresponding to each sampling branch; The data acquisition and processing unit receives the monitoring data and executes a data calibration and validity judgment algorithm to determine the final monitoring value; The output unit is used to output the final monitored value; The four-way valve integrates a resonant self-cleaning mechanism, which uses mechanical vibration to peel off the deposits attached to the inner wall of the four-way valve.

[0010] Furthermore, the measuring element includes a flow meter, and the monitoring data is single-point flow data; The data calibration and validity assessment algorithm includes: Multiple consecutive samples are taken within each measurement cycle. The relative deviations of the three single-point flow data in each sample are compared pairwise to obtain the temporary flow value and validity indicator of that sample. Statistical filtering is performed on multiple temporary flow values ​​to remove outliers, and the median or mean value is taken as the final flow value for this period. If the number of valid temporary traffic values ​​is insufficient, a retest or alarm will be triggered.

[0011] Furthermore, the judgment rule for the pairwise relative deviation comparison is as follows: If all pairwise relative deviations do not exceed the first threshold, then all three single-point flow data are valid, and the temporary flow value is taken as the median or mean of the three single-point flow data. If the relative deviation between only one single-point traffic data and the other two single-point traffic data exceeds the first threshold, while the relative deviation between the other two single-point traffic data does not exceed the first threshold, then the single-point traffic data is determined to be invalid, and the temporary traffic value is the average of the two valid single-point traffic data. If all pairwise relative deviations exceed the first threshold, the current sampling is invalid, and the temporary flow value is set to invalid data.

[0012] Furthermore, it also includes a long-term sensor health assessment module, which includes: Record the historical proportional coefficients between the three single-point flow data under normal operating conditions; For each measurement cycle, the current proportional coefficient is calculated. If the deviation from the historical benchmark exceeds the second threshold for multiple consecutive cycles, the corresponding measuring element is determined to have a long-term abnormality and an early warning is issued. When a certain measuring element is judged to be abnormal more than the preset number of consecutive cycles, the single-point flow data measured by that measuring element is automatically blocked, and only the other two measuring elements are used for measurement and output.

[0013] Furthermore, the resonant self-cleaning mechanism includes a piezoelectric ceramic block. A groove is provided below the connection between the outlet of the four-way valve and the internal water channel of the four-way valve. The piezoelectric ceramic block is installed at the bottom of the groove. The groove is also filled with a layer of glass microspheres that completely covers the piezoelectric ceramic block. A semi-permeable membrane that completely compacts the glass microsphere layer is covered at the opening of the groove. The semi-permeable membrane is sealed to the valve body, and the piezoelectric ceramic block is fixedly connected to the valve body.

[0014] Furthermore, the glass microsphere layer is filled with hydrophobic glass microspheres with a particle size of 0.10~0.25mm, and the piezoelectric ceramic block operates at a frequency of 73~74kHz; The thickness of the glass microsphere layer in the first groove is h1, and the filling rate of the glass microsphere layer is A1. The thickness of the glass microsphere layer in the second groove is h2, and the filling rate of the glass microsphere layer is A2. The thickness of the glass microsphere layer in the third groove is h3, and the filling rate of the glass microsphere layer is A3. h1>h2>h3; A1·h1=A2·h2=A3·h3.

[0015] Furthermore, the method for manufacturing the hydrophobic glass microspheres includes the following steps: Ethanol, water, and silane coupling agent are mixed in a mass ratio of (90~92):(5~6.5):(3~3.5), and glacial acetic acid is added dropwise to adjust the pH of the system to 4.0~5.0 to obtain the impregnation solution. The glass beads are completely immersed in the impregnation solution and stirred at a temperature of 40~50℃. After the reaction is complete, the particles are separated, washed, dried at room temperature, baked at 120-140℃ for at least 1 hour, and then cooled to obtain hydrophobic glass microspheres.

[0016] Secondly, an automatic flow measurement method for small and medium-sized rivers includes the following steps: The water flow is simultaneously distributed to three independent sampling branches via the inlet pipeline and a four-way valve; During non-measuring periods, activate the resonance-type self-cleaning mechanism to peel off the deposits attached to the inner wall of the four-way valve and allow it to stand and recover. Three monitoring data channels are collected synchronously multiple times within the measurement period. The three channels are then subjected to self-consistent judgment for single sampling and statistical filtering for cross-sampling to obtain the final monitoring value for this period. It monitors the consistency of data from all sources over a long period of time, and automatically blocks and issues warnings when a certain source continues to be abnormal.

[0017] Furthermore, when a certain measuring element is determined to be continuously abnormal and is blocked, the system retains the measurement and output of the other two monitoring data, and periodically attempts to reconnect the monitoring data measured by the blocked sampling branch in subsequent cycles. If the monitoring data returns to normal for three consecutive cycles, the blocking is lifted.

[0018] Furthermore, the resonant self-cleaning mechanism is set to allow at least 10 seconds of rest time after each cleaning action to eliminate residual disturbances to the water flow caused by mechanical vibration.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Mechanical resonance is used to remove silt, which avoids secondary interference to downstream flow velocity, pressure sensors and other measuring elements, thus ensuring measurement accuracy.

[0020] 2. By comparing data from three channels pairwise, it can automatically identify and eliminate transient abnormal data, demonstrating fault tolerance. Based on historical proportional coefficients and accumulated faults, it can provide early warnings of sensor performance degradation or blockage and automatically block faulty channels.

[0021] 3. The resonant dredging mechanism has low power consumption (only a few watts are needed for a single dredging operation), making it suitable for unmanned field stations powered by solar energy.

[0022] 4. The three sampling branches can be flexibly configured with different types of water quality and hydrological sensors (such as temperature, conductivity, turbidity, pH, dissolved oxygen, ammonia nitrogen, redox potential, etc.) to achieve simultaneous monitoring of multiple elements of river hydrology and water quality. Moreover, the data from each branch can be incorporated into the same data calibration and validity judgment framework to improve the reliability of comprehensive monitoring.

[0023] 5. Compared with traditional ultrasonic dredging, the resonant self-dredging mechanism of this invention concentrates the vibration energy to the inner wall adhesion layer through structural resonance, which has a better peeling effect on clay deposits and other substances, and will not damage the internal surface of the valve body or affect subsequent measurements due to excessive cavitation. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the four-way valve described in this invention; Figure 2 This is a top view of the four-way valve described in this invention; Figure 3 for Figure 2 BB view. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0026] The following detailed description of embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0027] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "left," "right," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] Example 1

[0030] like Figure 1 As shown, an automatic flow measurement device for small and medium-sized rivers includes: Water inlet pipeline; There are three sampling branches. The four-way valve includes a valve body 10, a four-way valve inlet 11, and three four-way valve outlets 12 with the same flow channel structure and the same flow resistance. The valve body 10 is provided with an internal water channel 13 that is connected to both the four-way valve inlet 11 and the four-way valve outlet 12. The three four-way valve outlets 12 are respectively connected to three sampling branches. Measuring elements are used to measure the monitoring data corresponding to each sampling branch; The data acquisition and processing unit receives the monitoring data and executes a data calibration and validity judgment algorithm to determine the final monitoring value; The output unit is used to output the final monitored value; The four-way valve integrates a resonant self-cleaning mechanism, which uses mechanical vibration to peel off the deposits attached to the inner wall of the four-way valve.

[0031] In this embodiment, the measuring element includes a flow meter, and the monitoring data is single-point flow data; In some other embodiments, the measuring element may further include, as needed: Water temperature sensors can be platinum resistance, thermocouples, or semiconductor temperature sensors. Conductivity sensor, using a two-electrode or four-electrode type conductivity sensor; The turbidity sensor is an optical turbidity sensor. The pH sensor uses a glass electrode pH sensor. Dissolved oxygen sensor, employing either fluorescence-based dissolved oxygen sensor or polarographic electrode; Ammonia nitrogen sensors employ either ion-selective electrodes or optical colorimetric sensors. The redox potential sensor uses a platinum electrode and a reference electrode.

[0032] The data calibration and validity assessment algorithm includes: 1. Single-cycle multiple sampling is used to resist transient disturbances in the time domain; Multiple consecutive samples are taken within each measurement cycle (e.g., 1 minute) (e.g., 5 samples with a 2-second interval between each sample). The relative deviations of the three single-point flow data from each sample are compared pairwise to obtain the temporary flow value and validity indicator for that sample. Statistical filtering is performed on multiple temporary flow values ​​to remove outliers, and the median or mean value is taken as the final flow value for this period. If the number of valid temporary traffic values ​​is insufficient, a retest or alarm will be triggered.

[0033] 2. For the three single-point flow data sampled in the kth sampling (Q respectively) 1k Q 2k Q 3k The judgment rule based on pairwise relative deviation comparison (three-way self-consistent algorithm) is as follows: If all pairwise relative deviations do not exceed the first threshold (e.g., 8%), then all three single-point flow data are valid, and the temporary flow value q is... k Take three single-point flow data (Q) 1k Q 2k Q 3k The median or mean of ( ); If there is only one single point of traffic data (such as Q) 1k ) and the single-point flow data of the other two paths (such as Q) 2k Q 3k The relative deviations between the two data points (Q, Q, Q) all exceeded the first threshold, while the other two single-point flow data points (Q, Q, Q) were also affected. 2k Q 3k If the relative deviation between the two paths does not exceed the first threshold, that is, if the other two paths are consistent, then the single-point flow data of that path is determined to be invalid, and the temporary flow value is taken from the two valid single-point flow data (such as Q). 2k Q 3k The mean of ) If all pairwise relative deviations exceed the first threshold, the current sampling is invalid, and the temporary flow value is set to invalid data.

[0034] 3. In some other embodiments, the automatic flow measurement device for small and medium-sized rivers further includes a long-term sensor health assessment module, which includes: Record the historical proportional coefficients between the three single-point flow data under normal operating conditions; For each measurement cycle, the current proportional coefficient is calculated. If the deviation from the historical benchmark exceeds the second threshold (e.g., 15%) for multiple consecutive cycles (e.g., 3 cycles), the corresponding measuring element is determined to have a long-term abnormality and an early warning is issued. When a certain measuring element is judged to be abnormal more than the preset number (e.g., 4 times) in multiple consecutive cycles (e.g., 5 cycles), the single-point flow data measured by that measuring element will be automatically blocked, and only the other two measuring elements will be used for measurement and output until manual reset or self-test recovery.

[0035] Example 2

[0036] Based on Example 1, such as Figures 1-3 As shown, the resonant self-cleaning mechanism includes a piezoelectric ceramic block 21. A groove is provided below the connection between the outlet 12 of the four-way valve and the internal water channel 13 of the four-way valve. The piezoelectric ceramic block 21 is installed at the bottom of the groove. The groove is also filled with a glass microsphere layer 22 that completely covers the piezoelectric ceramic block 21. A semi-permeable membrane 23 that completely compacts the glass microsphere layer 22 is covered at the opening of the groove. The semi-permeable membrane 23 is sealed to the valve body 10. The piezoelectric ceramic block 21 is fixedly connected to the valve body 10.

[0037] In some embodiments, the drive circuit for driving the piezoelectric ceramic block 21 is integrated into the valve body 10, and its two electrode plates 40 can be connected to an external power source.

[0038] The glass microsphere layer 22 is filled with hydrophobic glass microspheres with a particle size of 0.10~0.25mm, and the piezoelectric ceramic block 21 operates at a frequency of 73~74kHz. The thickness of the glass microsphere layer 22 in the first groove is h1, and the filling rate of the glass microsphere layer 22 is A1; The thickness of the glass microsphere layer 22 in the second groove is h2, and the filling rate of the glass microsphere layer 22 is A2; The thickness of the glass microsphere layer 22 in the third groove is h3, and the filling rate of the glass microsphere layer 22 is A3; h1 > h2 > h3; h1 = 2.7 cm, A1 = 75%; h2 = 2.5cm, A2 = 81%; h3=2.2cm, A3=92%; The value of A1·h1=A2·h2=A3·h3 is 2.0; In some other embodiments, the method for fabricating the hydrophobic glass microspheres includes the following steps: Ethanol, water, and silane coupling agent are mixed in a mass ratio of (90~92):(5~6.5):(3~3.5), and glacial acetic acid is added dropwise to adjust the pH of the system to 4.0~5.0 to obtain the impregnation solution. The glass beads are completely immersed in the impregnation solution and stirred at a temperature of 40~50℃. After the reaction is complete, the particles are separated, washed, dried at room temperature, baked at 120-140℃ for at least 1 hour, and then cooled to obtain hydrophobic glass microspheres.

[0039] An automatic flow measurement method for small and medium-sized rivers includes the following steps: The water flow is simultaneously distributed to three independent sampling branches via the inlet pipeline and a four-way valve; During non-measuring periods, activate the resonance-type self-cleaning mechanism to peel off the deposits attached to the inner wall of the four-way valve and allow it to stand and recover. Three monitoring data channels are collected synchronously multiple times within the measurement period. The three channels are then subjected to self-consistent judgment for single sampling and statistical filtering for cross-sampling to obtain the final monitoring value for this period. It monitors the consistency of data from all sources over a long period of time, and automatically blocks and issues warnings when a certain source continues to be abnormal.

[0040] In some other embodiments, when a certain measuring element is determined to be continuously abnormal and is blocked, the system retains the measurement and output of the other two monitoring data, and periodically attempts to reconnect the monitoring data measured by the blocked sampling branch in subsequent cycles. If the monitoring data returns to normal for three consecutive cycles, the blocking is lifted.

[0041] In some other embodiments, the resonant self-cleaning mechanism is set to a resting time of at least 10 seconds after each cleaning action to eliminate residual disturbance of the water flow caused by mechanical vibration.

[0042] In this embodiment, the mid-frequency vibration generated by the piezoelectric ceramic block 21 is scattered, reflected, absorbed and rubbed by the glass microsphere layer 22. After a certain degree of attenuation, the residual ultrasonic waves can still clean the deposits on the inner wall, but the cleaning effect is generally poor. However, the penetrating power of these residual ultrasonic waves is greatly reduced, and the interference to other measuring elements in the vicinity is significantly reduced.

[0043] Therefore, in this invention, by causing the three glass microsphere layers 22 to resonate under a specific vibration field, the adhering material on the inner wall within 2-5 cm of the glass microsphere layer 22 can be peeled off due to resonance. Specifically, a semi-permeable membrane 23 must be used, preferably a wear-resistant PVDF or PES membrane; before use, it is soaked in water for 24 hours, allowing water to penetrate the semi-permeable membrane and fill the groove with water; during subsequent use, since sampling is continuous, the pipe is mostly filled with water, and even in special cases where it is dry, it can be run for a period of time before measurement.

[0044] The filling rate of the glass microsphere layer refers to the ratio of the accumulated volume of hydrophobic glass microspheres in the groove to the remaining volume in the groove. The remaining volume in the groove refers to the difference between the volume of the groove and the volume of the piezoelectric ceramic block 21. The filling rate reflects the compacted state of the hydrophobic glass microspheres in the groove.

[0045] Since the three vibration sources on the same valve body 10 are not far apart, they will naturally have a certain influence. Furthermore, by controlling the filling rate and ensuring the internal water channel 13 of the four-way valve is filled with water, and by controlling A1·h1=A2·h2=A3·h3, the hydrophobic glass microspheres with varying densities resonate under the combined vibration fields of the three vibration sources. This effectively peels off the deposits adhering to the inner wall of the resonance area. It should be noted that this resonance is particularly effective for soil, but its effect on other substances, such as colloidal substances, is generally limited. Clay and gelatinized starch can be used for comparison.

[0046] In this invention, the peeling effect is easily measured, mainly by checking whether resonance occurs in the vibration field area enclosed by the three vibration sources. If resonance does not occur, the vibration intensity near each of the three vibration sources varies greatly due to differences in thickness and filling rate. Therefore, it can be characterized by measuring the real-time flow difference (the difference between real-time flow and standard flow) flowing through the three four-way valve outlets 12. The real-time flow is the real-time flow of the three four-way valve outlets 12 measured by activating the three piezoelectric ceramic blocks 21; the standard flow is the real-time flow of the three four-way valve outlets 12 measured without activating the three piezoelectric ceramic blocks 21, and the average value is taken. In the experiment, the ratio of the difference between the real-time flow and the standard flow to the standard flow is the deviation rate. Through verification, when the deviation rate is less than or equal to 8%, resonance is considered to have occurred; if the deviation rate is greater than 8%, weak resonance or even no resonance is considered to have occurred. The experimental results are shown in Table 1: Table 1

[0047] As shown in Table 1, the data from Example 2 indicate that the deviation rates of the three four-way valve outlets 12 are 7.6%, 7.1%, and 6.5%, respectively. The very small deviation rate indicates that the flow rate of the three channels is highly consistent, which is in line with the expectation of resonance.

[0048] Control Experiment 1: The difference between this example and Example 2 is that A1=A2=A3=75%, h1=h2=h3=2.7cm; all other aspects are the same.

[0049] As shown in Table 1, when the thickness and filling rate are equal, the three vibration sources work independently and cannot form coupled resonance, resulting in poor dredging effect (with a deviation rate as high as 21.4%). This indicates that differential thickness is a necessary condition for resonance.

[0050] Control Experiment 2: The difference between this example and Example 2 is that A1=A2=75%, A3=92%, h1=h2=2.7cm, h3=2.2cm; all other measurements are the same.

[0051] As shown in Table 1, the resonance condition is not met because the unequal design condition of h1 > h2 > h3 (where h1 is any three values, but the intention here is to express that the three values ​​cannot be equal) is not satisfied, and the deviation rate is still relatively high (minimum 10.8%). This indicates that unequal thickness is crucial for resonance formation.

[0052] Control Experiment 3: The difference between this example and Example 2 is that the glass microsphere layer 22 in this example is made of ordinary glass microspheres without hydrophobic modification, while the rest are the same. After hydrophobic modification, cavitation can propagate more widely under the action of water, thereby allowing the semipermeable membrane 23 to vibrate better.

[0053] As shown in Table 1, non-hydrophobic glass microspheres can cause the deviation rate to increase to more than 15%, indicating that hydrophobic treatment helps cavitation-assisted dredging. The concentration of the transmitted vibration can be attenuated by the glass microsphere layer 22 and then diffused to a certain extent. Finally, it is widely transmitted through the semi-permeable membrane 23. Although the final ultrasonic vibration is slightly enhanced, it is still weaker than the peeling and cleaning directly using an ultrasonic transducer.

[0054] Control Experiment 4: The difference between this example and Example 2 is that aluminum foil is used instead of semi-permeable membrane 23 in this example, otherwise they are the same.

[0055] As shown in Table 1, when aluminum foil is used instead of a semi-permeable membrane, the water inside and outside the membrane cannot be effectively exchanged, and resonance cannot be formed. The groove is a medium layer with high porosity, resulting in strong vibration attenuation and poor dredging effect.

[0056] Control Experiment 5: The difference between this example and Example 2 is that the glass microsphere layer 22 is not installed in this example, and its interior is water, but everything else is the same.

[0057] As shown in Table 1, without the glass microsphere layer, the piezoelectric ceramic directly vibrates the water body, but lacks resonant amplification and directional energy accumulation, which may cause flow turbulence and has the largest deviation rate (33.4%).

[0058] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0059] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An automatic flow measurement device for small and medium-sized rivers, comprising: Water inlet pipeline; There are three sampling branches. The four-way valve includes a valve body, a four-way valve inlet, and three four-way valve outlets with the same flow channel structure and consistent flow resistance. The valve body is provided with an internal water channel that is connected to both the four-way valve inlet and the four-way valve outlet. The three four-way valve outlets are respectively connected to three sampling branches. Measuring elements are used to measure the monitoring data corresponding to each sampling branch; Its characteristic is that it further includes: The data acquisition and processing unit receives the monitoring data and executes a data calibration and validity judgment algorithm to determine the final monitoring value; The output unit is used to output the final monitored value; The four-way valve integrates a resonant self-cleaning mechanism, which uses mechanical vibration to peel off the deposits attached to the inner wall of the four-way valve.

2. The automatic flow measurement device for small and medium-sized rivers according to claim 1, characterized in that: The measuring element includes a flow meter, and the monitoring data is single-point flow data; The data calibration and validity assessment algorithm includes: Multiple consecutive samples are taken within each measurement cycle. The relative deviations of the three single-point flow data in each sample are compared pairwise to obtain the temporary flow value and validity indicator of that sample. Statistical filtering is performed on multiple temporary flow values ​​to remove outliers, and the median or mean value is taken as the final flow value for this period. If the number of valid temporary traffic values ​​is insufficient, a retest or alarm will be triggered.

3. The automatic flow measurement device for small and medium-sized rivers according to claim 2, characterized in that: The judgment rule for the pairwise relative deviation comparison is as follows: If all pairwise relative deviations do not exceed the first threshold, then all three single-point flow data are valid, and the temporary flow value is taken as the median or mean of the three single-point flow data. If the relative deviation between only one single-point traffic data and the other two single-point traffic data exceeds the first threshold, while the relative deviation between the other two single-point traffic data does not exceed the first threshold, then the single-point traffic data is determined to be invalid, and the temporary traffic value is the average of the two valid single-point traffic data. If all pairwise relative deviations exceed the first threshold, the current sampling is invalid, and the temporary flow value is set to invalid data.

4. The automatic flow measurement device for small and medium-sized rivers according to claim 2, characterized in that: It also includes a long-term sensor health assessment module, which includes: Record the historical proportional coefficients between the three single-point flow data under normal operating conditions; For each measurement cycle, the current proportional coefficient is calculated. If the deviation from the historical benchmark exceeds the second threshold for multiple consecutive cycles, the corresponding measuring element is determined to have a long-term abnormality and an early warning is issued. When a certain measuring element is judged to be abnormal more than the preset number of consecutive cycles, the single-point flow data measured by that measuring element is automatically blocked, and only the other two measuring elements are used for measurement and output.

5. The automatic flow measurement device for small and medium-sized rivers according to claim 1, characterized in that: The resonant self-cleaning mechanism includes a piezoelectric ceramic block. A groove is provided below the connection between the outlet of the four-way valve and the internal water channel of the four-way valve. The piezoelectric ceramic block is installed at the bottom of the groove. The groove is also filled with a layer of glass microspheres that completely covers the piezoelectric ceramic block. A semi-permeable membrane that completely compacts the glass microsphere layer is covered at the opening of the groove. The semi-permeable membrane is sealed to the valve body. The piezoelectric ceramic block is fixedly connected to the valve body.

6. The automatic flow measurement device for small and medium-sized rivers according to claim 5, characterized in that: The glass microsphere layer is filled with hydrophobic glass microspheres with a particle size of 0.10~0.25mm, and the piezoelectric ceramic block operates at a frequency of 73~74kHz. The thickness of the glass microsphere layer in the first groove is h1, and the filling rate of the glass microsphere layer is A1. The thickness of the glass microsphere layer in the second groove is h2, and the filling rate of the glass microsphere layer is A2. The thickness of the glass microsphere layer in the third groove is h3, and the filling rate of the glass microsphere layer is A3. h1>h2>h3; A1·h1=A2·h2=A3·h3.

7. The automatic flow measurement device for small and medium-sized rivers according to claim 6, characterized in that: The method for preparing the hydrophobic glass microspheres includes the following steps: Ethanol, water, and silane coupling agent are mixed in a mass ratio of (90~92):(5~6.5):(3~3.5), and glacial acetic acid is added dropwise to adjust the pH of the system to 4.0~5.0 to obtain the impregnation solution. The glass beads are completely immersed in the impregnation solution and stirred at a temperature of 40~50℃. After the reaction is complete, the particles are separated, washed, dried at room temperature, baked at 120-140℃ for at least 1 hour, and then cooled to obtain hydrophobic glass microspheres.

8. A method for automatic flow measurement of small and medium-sized rivers, executed by the automatic flow measurement device for small and medium-sized rivers as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The water flow is simultaneously distributed to three independent sampling branches via the inlet pipeline and a four-way valve; During non-measuring periods, activate the resonance-type self-cleaning mechanism to peel off the deposits attached to the inner wall of the four-way valve and allow it to stand and recover. Three monitoring data channels are collected synchronously multiple times within the measurement period. The three channels are then subjected to self-consistent judgment for single sampling and statistical filtering for cross-sampling to obtain the final monitoring value for this period. It monitors the consistency of data from all sources over a long period of time, and automatically blocks and issues warnings when a certain source continues to be abnormal.

9. The automatic flow measurement method for small and medium-sized rivers according to claim 8, characterized in that, When a certain measuring element is determined to be continuously abnormal and is blocked, the system retains the measurement and output of the other two monitoring data, and periodically attempts to reconnect the monitoring data measured by the blocked sampling branch in subsequent cycles. If the monitoring data returns to normal for three consecutive cycles, the blocking is lifted.

10. The automatic flow measurement method for small and medium-sized rivers according to claim 8, characterized in that, The resonant self-cleaning mechanism is set to allow at least 10 seconds of rest time after each cleaning action to eliminate residual disturbances to the water flow caused by mechanical vibration.

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