Virtual multi-channel anti-bubble ultrasonic flow metering method and water meter

Abstract

This invention relates to a virtual multi-channel anti-bubble ultrasonic flow metering method and water meter, comprising: Step S1: establishing multiple virtual channels from the same physical channel including a first transducer AT and a second transducer AR; Step S2: the second transducer AR receives and measures the signal emitted by the first transducer AT, and the first transducer AT receives and measures the signal emitted by the second transducer AR; Step S3: identifying whether each virtual channel is wave-jumping; Step S4: updating the wave-jumping count jump_cnt for each virtual channel; Step S5: updating the overall bubble condition bubble based on the wave-jumping count jump_cnt of all virtual channels; Step S6: calculating the overall reverse and forward flow time difference t_a based on different overall bubble conditions bubble; Step S7: calculating the flow rate within the sampling time. This invention establishes multiple virtual channels using different measurement waveform configurations on the same physical channel, improving the stability and accuracy of water flow metering in ultrasonic water meters; since the number of physical channels remains constant, it balances performance and cost.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic flow measurement, and in particular to a virtual multi-channel anti-bubble ultrasonic flow measurement method and water meter. Background Technology

[0002] Ultrasonic water meters transmit ultrasonic signals into the water flow via a transmitting transducer and capture the ultrasonic signals after propagation through the water flow via a receiving transducer. Using the time difference in ultrasonic wave propagation in the upstream and downstream directions, combined with parameters such as pipe diameter and fluid sound velocity, the water flow rate is calculated using a formula. However, in practical applications, air bubbles inevitably mix into the water flow. These bubbles can be caused by factors such as residual air during pipeline maintenance or filling; the release of dissolved gases (such as oxygen and carbon dioxide) due to water temperature changes; and the formation of air bubbles due to vortices created by high-speed water flow within pipes. These bubbles exist in the water flow in the form of dispersed microbubbles, flocculent bubbles, or larger air masses, significantly negatively impacting the metering performance and operational stability of ultrasonic water meters.

[0003] 1) Interference with ultrasonic signal propagation, leading to signal attenuation and distortion: The acoustic impedance difference between bubbles and water is extremely large (air acoustic impedance is about 1 / 3400 of water). When ultrasonic waves encounter bubbles, strong reflection, scattering, and refraction occur. On the one hand, most of the acoustic energy is lost, and the signal strength acquired by the receiving transducer is greatly attenuated, or even unable to capture the ultrasonic signal; for example, ... Figure 9a and Figure 9b As shown, the received amplitude decreases under the bubble, and the same FHL level collide with the subsequent wave, causing the measurement of the time of flight to be incorrect, i.e., wave skipping; on the other hand, the scattered signal will generate multipath propagation, causing the signal detected by the receiver to have phase shift and waveform distortion, interfering with the accuracy of time difference measurement, and thus causing flow calculation error.

[0004] 2) Reduced metering accuracy and increased error range: The flow calculation result of ultrasonic water meters is directly related to the ultrasonic wave propagation time difference. The presence of air bubbles will disrupt the stable flow field of water flow, forming local turbulence or uneven flow velocity distribution, which will increase the deviation between the actual flow velocity on the ultrasonic wave propagation path and the average flow velocity of the pipe. At the same time, air bubbles occupy part of the water flow cross section, which reduces the effective water flow area actually involved in the metering, while the water meter still calculates based on the entire pipe cross section, further aggravating the metering deviation.

[0005] Experimental data shows that when the volume fraction of air bubbles in the water flow reaches 0.5%, the measurement error of the ultrasonic water meter will exceed the ±2% error range; when the volume fraction of air bubbles exceeds 2%, the measurement error can expand to more than ±10%. Moreover, under low flow conditions, the impact of air bubbles on measurement accuracy is more significant, and problems such as "slow measurement" or "missed measurement" are likely to occur. Summary of the Invention

[0006] This invention aims to solve the above-mentioned problems by providing a virtual multi-channel anti-bubble ultrasonic flow metering method and water meter, thus resolving the aforementioned issues.

[0007] A virtual multi-channel anti-bubble ultrasonic flow metering method includes:

[0008] Step S1: Establish multiple virtual channels from the same physical channel, which includes the first transducer AT and the second transducer AR.

[0009] Step S2: The second transducer AR receives and measures the signal emitted by the first transducer AT; the first transducer AT receives and measures the signal emitted by the second transducer AR.

[0010] Step S3: Identify whether each virtual channel has skipped waveforms;

[0011] Step S4: Update the jump count jump_cnt for each virtual channel;

[0012] Step S5: Update the overall bubble status based on the jump count (jump_cnt) of all virtual channels;

[0013] Step S6: Calculate the overall countercurrent and concurrent time difference based on different overall bubble conditions. t_a;

[0014] Step S7: Calculate the flow rate during the sampling time.

[0015] Preferably, the method further includes the following steps:

[0016] Step S8: Repeat steps S2 to S7 to calculate the flow rate for each sampling time. The wave jump count jump_cnt for each sampling time is updated based on the wave jump count jump_cnt of the previous sampling time.

[0017] Step S9: Add up the flow rates of all sampling times to obtain the total flow rate.

[0018] Preferably, in step S1, the physical channels are constructed using different excitation waveform parameters and / or received signal parameters to establish multiple virtual channels;

[0019] The excitation waveform parameters include waveforms without phase insertion, waveforms with high phase insertion, and waveforms with low phase insertion; the received signal parameters include the first wave detection level FHL, which is alternately detected at different received wave intervals, zero-crossing detection of rising edge, and zero-crossing detection of falling edge.

[0020] Preferably, step S1 includes:

[0021] Step S11: Call the built-in first wave detection level FHL in the ultrasonic meter;

[0022] Step S12: The first transducer AT and the second transducer AR respectively transmit waveforms, wherein the waveforms are at least one of no phase insertion, high phase insertion, and low phase insertion.

[0023] Preferably, in step S2, the second transducer AR measures the downstream flight time Td, the zero-crossing time Td_pre before the downstream insertion phase, and the zero-crossing time Td_pos after the downstream insertion phase; the first transducer AT measures the upstream flight time Tu, the zero-crossing time Tu_pre before the upstream insertion phase, and the zero-crossing time Tu_pos after the upstream insertion phase.

[0024] Optionally, step S3 identifies whether each virtual channel skips waves by using the phase insertion method, including the following steps:

[0025] Step S31: Calculate the time difference between the zero-crossing points before and after the downstream insertion phase. Pd = Td_pos - Td_pre, calculates the zero-crossing time difference before and after the countercurrent insertion phase. Pu = Tu_pos - Tu_pre;

[0026] Step S32: Calculate | Pd- Pw| and| Pu- Pw|, where Pw is the average time difference between the zero-crossing points before and after the insertion phase obtained without bubbles;

[0027] Step S33: When | Pd- Pw|>P_limit and / or| Pu- If Pw|>P_limit, the virtual channel is identified as a hopping channel; otherwise, it is identified as a non-hopping channel. P_limit is the hopping detection threshold, typically set to (0.4~0.7)*| Pj- Pw|, Pj is the average value of the zero-crossing time difference before and after the insertion phase obtained from the simulated wave skipping (i.e., the average value of Td_pos-Td_pre and Tu_pos-Tu_pre under the simulated wave skipping). Normally, FHL is on the third wave. By setting FHL to the second wave, the zero-crossing detection moves forward as a whole. The simulated wave skipping is used as a debugging method to obtain the wave skipping detection threshold P_limit.

[0028] Optionally, step S3 identifies whether each virtual channel skips waves using time and judgment methods.

[0029] Preferably, step S4 includes: when a jump wave is detected in step S3, the current channel jump wave count jump_cnt is incremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call; when no jump wave is detected in step S3, the current channel jump wave count jump_cnt is decremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call.

[0030] The minimum value of the wave jump count jump_cnt is 0, and the maximum value is the counting threshold jump_fault_cnt_this.

[0031] Preferably, step S5 includes:

[0032] After incrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt with the preset value jump_state. The preset value is less than the counting threshold jump_fault_cnt_this and greater than 0. When the jump count jump_cnt is less than or equal to the preset value jump_state, output the second overall bubble condition bubble1. When the jump count jump_cnt is greater than the preset value jump_state, compare the jump count jump_cnt of all channels with the counting threshold jump_fault_cnt_this. If the jump count jump_cnt of all channels is greater than or equal to the counting threshold jump_fault_cnt_this, output the third overall bubble condition bubble2; otherwise, output the second overall bubble condition bubble1.

[0033] After decrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt of all channels with 0. If the jump count jump_cnt of all channels is equal to 0, output the first overall bubble condition bubble0; otherwise, output the second overall bubble condition bubble1.

[0034] Preferably, step S6 includes: when the first overall bubble condition is bubble0, the overall countercurrent and concurrent flow time difference. t_a is the time difference between forward and reverse flow for all audio channels. The average value of t_i; the overall countercurrent and concurrent time difference when the second overall bubble condition is bubble1. t_a is the time difference between the upstream and downstream currents of all channels whose jump counts jump_cnt are less than or equal to the preset value jump_state. The average value of t_i; the overall countercurrent and concurrent time difference when the third overall bubble condition is bubble2. t_a=0;

[0035] The time difference between countercurrent and concurrent current t_i = Tu_i - Td_i, where i is the virtual channel number.

[0036] Preferably, step S7 includes:

[0037] Step S71: Calculate the water flow velocity v = t_a*C*C / (2*L), where C is the speed of sound and L is the ultrasonic transmission distance in the direction of water flow;

[0038] Step S72: Calculate the instantaneous flow rate Q = π * D * D / 4 * v * k, where D is the pipe diameter, v is the water flow velocity, and k is the flow compensation coefficient;

[0039] Step S73: Calculate the cumulative flow Σ=Q*CT, where CT is the measurement sampling time.

[0040] A water meter using the aforementioned virtual multi-channel anti-bubble ultrasonic flow metering method includes: a pipe section and a control device, wherein at least one pair of first transducers AT and second transducers AR are fixedly installed inside the pipe section, and the control device is electrically connected to the first transducers AT and the second transducers AR respectively.

[0041] This invention has the following advantages: Multiple virtual channels are established by using different measurement waveform configurations within the same physical channel. Each channel performs bubble detection and waveform parameter adjustment. The different waveform parameters between virtual channels adapt to different types of bubbles (discrete small bubbles, clustered large bubbles), improving the stability and accuracy of water flow measurement in ultrasonic water meters. Since the number of physical channels remains constant, both performance and cost are balanced. When a single virtual channel continuously skips waves, it indicates a bubble condition, and the sampling frequency and measurement waveform parameters are adjusted to increase the amplitude of the ultrasonic received signal under bubble conditions, thereby improving measurement accuracy. Normal operation is only restored when all channels are free of wave skipping, preventing frequent entry and exit from bubble conditions and improving stability. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other embodiments can be derived from the provided drawings without creative effort.

[0043] Figure 1: A schematic diagram of the structure of this invention (one physical audio channel);

[0044] Figure 2 : A schematic diagram of the structure of this invention (two physical channels);

[0045] Figure 3 : Flowchart of the measurement method of this invention;

[0046] Figure 4 Flowchart of steps S4 to S7;

[0047] Figure 5a A schematic diagram of the transmitted waveform without phase insertion;

[0048] Figure 5b : A schematic diagram of the high-phase transmission waveform;

[0049] Figure 5c : A schematic diagram of the low-phase transmission waveform;

[0050] Figure 6a The received waveform diagram that distinguishes virtual audio channels by the rising edge (dot) and falling edge (triangle) at the zero point;

[0051] Figure 6b : Figure 6a Zero-crossing detection comparator output diagram (blue waveform in the diagram corresponds to...) Figure 6a The dot crosses zero, corresponding to the purple waveform in the diagram. Figure 6a (the triangle passes through the zero point)

[0052] Figure 7a : Received waveform diagram of the first wave detection level FHL, which is detected by alternating interval waves on different waves;

[0053] Figure 7b : Figure 7a Zero-crossing detection comparator output diagram (blue waveform in the diagram corresponds to...) Figure 7a The blue dot crosses zero, corresponding to the yellow waveform in the diagram. Figure 7a (The yellow triangle passes through the zero point)

[0054] Figure 8 Step S3: Schematic diagram of the phase judgment method;

[0055] Figure 9a Background: Received waveform diagram of wave skipping in the technology;

[0056] Figure 9b : Figure 9a Zero-crossing detection comparator output diagram (blue waveform in the diagram corresponds to...) Figure 9a The blue dot crosses zero, corresponding to the red waveform in the diagram. Figure 9a (The red triangle passes through the zero point). Detailed Implementation

[0057] The present invention will be further described below with reference to the accompanying drawings and examples:

[0058] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0060] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0061] Example 1:

[0062] like Figures 1 to 8 As shown, this embodiment provides a virtual multi-channel anti-bubble ultrasonic flow metering method, including:

[0063] Step S1: Multiple virtual channels are established from the same physical channel, which includes the first transducer AT and the second transducer AR; wherein, a single physical channel can establish two or four virtual channels; for example... Figure 1 As shown, one physical channel A creates four virtual channels; two physical channels can create four or eight virtual channels; as... Figure 2 As shown, two physical channels A each create two virtual channels, for a total of four virtual channels;

[0064] Step S2: The second transducer AR receives and measures the signal emitted by the first transducer AT; the first transducer AT receives and measures the signal emitted by the second transducer AR.

[0065] Step S3: Identify whether each virtual channel has skipped waveforms;

[0066] Step S4: Update the jump count jump_cnt for each virtual channel;

[0067] Step S5: Update the overall bubble status based on the jump count (jump_cnt) of all virtual channels;

[0068] Step S6: Calculate the overall countercurrent and concurrent time difference based on different overall bubble conditions. t_a;

[0069] Step S7: Calculate the flow rate during the sampling time.

[0070] Preferably, the method further includes the following steps:

[0071] Step S8: Repeat steps S2 to S7 to calculate the flow rate for each sampling time. The wave jump count jump_cnt for each sampling time is updated based on the wave jump count jump_cnt of the previous sampling time.

[0072] Step S9: Add up the flow rates of all sampling times to obtain the total flow rate.

[0073] Preferably, in step S1, the physical channels are constructed using different excitation waveform parameters and / or received signal parameters to establish multiple virtual channels, as shown below:

[0074] (a) Establishing multiple virtual channels by transmitting waveforms: such as Figure 5a , Figure 5b and Figure 5c As shown, there are no phase insertion (time and judgment method), high phase insertion, low phase insertion, etc.; different virtual channels are distinguished by different waveforms;

[0075] (b) Establishing multiple virtual channels by receiving parameters: such as Figure 6a and Figure 6b As shown, the initial detection levels FHL are the same, with zero-crossing detection of the rising edge (dot) and zero-crossing detection of the falling edge (triangle); as... Figure 7a and Figure 7b As shown, the two initial detection levels FHL (in) Figure 7a The diagram shows the detection of zero-crossing points at different starting wave intervals (yellow and blue, respectively). For example, the first wave detection level FHL detects the blue dot zero-crossing point at the second starting wave interval, while another first wave detection level FHL detects the orange triangle zero-crossing point at the third starting wave interval. Different virtual channels are distinguished by detecting at different positions of the received waveform.

[0076] (c) Multiple virtual channels are distinguished by the combination of transmitted waveform and received parameters; for example, channel 0 is inserted with a low phase detection rising edge, channel 1 is inserted with a low phase detection falling edge, channel 2 is inserted with a high phase detection rising edge, and channel 3 is inserted with a high phase detection falling edge.

[0077] The excitation waveform parameters include waveforms without phase insertion, waveforms with high phase insertion, and waveforms with low phase insertion; the received signal parameters include the first wave detection level FHL, which is alternately detected at different received wave intervals, zero-crossing detection of rising edge, and zero-crossing detection of falling edge.

[0078] Preferably, step S1 includes:

[0079] Step S11: Call the built-in first wave detection level FHL in the ultrasonic meter;

[0080] Step S12: The first transducer AT and the second transducer AR respectively transmit waveforms, wherein the waveforms are at least one of no phase insertion, high phase insertion, and low phase insertion.

[0081] Preferably, in step S2, the second transducer AR measures the downstream flight time Td, the zero-crossing time Td_pre before the downstream insertion phase, and the zero-crossing time Td_pos after the downstream insertion phase; the first transducer AT measures the upstream flight time Tu, the zero-crossing time Tu_pre before the upstream insertion phase, and the zero-crossing time Tu_pos after the upstream insertion phase.

[0082] Optionally, step S3 identifies whether each virtual channel skips waveforms using the phase insertion method, including the following steps: Previously, in step S1, multiple virtual channels were distinguished by combining the transmitted waveform and received parameters, i.e., two types of waveforms, high-phase and low-phase, were transmitted. The rising and falling edges of each waveform were detected to construct four virtual channels. For example, channel 0 inserts a low-phase waveform with a rising edge detection, channel 1 inserts a low-phase waveform with a falling edge detection, channel 2 inserts a high-phase waveform with a rising edge detection, and channel 3 inserts a high-phase waveform with a falling edge detection.

[0083] like Figure 8 As shown, the dark red rhombus represents the zero-crossing time Tpre before phase insertion (either one zero-crossing point or the average of several zero-crossing points can be used), and the orange triangle represents the zero-crossing time Tpos after phase insertion (either one zero-crossing point or the average of several zero-crossing points can be used). Records are saved without bubbles. Pw=(Tpos-Tpre), simulating a jumping wave (e.g.) Figure 9a and Figure 9b The correct FHL is set on the second oscillation wave (either the first or third oscillation wave is set, simulating a jumping wave). The zero-crossing point detected by Tpre / Tpos is moved forward or backward, and the jumping wave is recorded. Pj=(Tpos_j-Tpre_j), set the wave skipping detection threshold P_limit=(0.4~0.7)*|( Pj- Pw|;During the measurement process, the calculation| Pd- By comparing Pw| with P_limit, it can be determined whether a wave skipping occurs;

[0084] Step S31: Calculate the time difference between the zero-crossing points before and after the downstream insertion phase. Pd = Td_pos - Td_pre, calculates the zero-crossing time difference before and after the countercurrent insertion phase. Pu = Tu_pos - Tu_pre; where Td_pos and Tu_pos can be... Figure 8 Take the average of any one or more of the zero-crossing points of the orange triangle, where Td_pre and Tu_pre can be... Figure 8 The average value is taken from any one or more of the zero-crossing points of the dark red rhombus. Regardless of whether one or more points are selected for averaging, the selected position relative to FHL is fixed in each calculation.

[0085] Step S32: Calculate | Pd- Pw| and| Pu- Pw|, where Pw is the average value of the zero-crossing time difference before and after the insertion phase obtained without bubbles. Pw is stored in the memory of the control device;

[0086] Step S33: When | Pd- Pw|>P_limit and / or| Pu- If Pw|>P_limit, the virtual channel is identified as a hopping channel; otherwise, it is identified as a non-hopping channel. P_limit is the hopping detection threshold, typically set to (0.4~0.7)*| Pj- Pw|, Pj is the average time difference between the zero crossing points before and after the insertion phase obtained by the simulated wave jumping (i.e., the average of Td_pos-Td_pre and Tu_pos-Tu_pre under the simulated wave jumping), and P_limit is stored in the memory of the control device.

[0087] Optionally, step S3 identifies whether each virtual channel skips waveforms using time and judgment methods, and calculates... S = |SumT - SumNtc|, where SumT = Tu + Td are the measured countercurrent and concurrent flow times, SumNtc = 2L / C are the theoretical countercurrent and concurrent flow times, C is the sound velocity which can be calculated using the water medium sound velocity-temperature empirical model, and the temperature is obtained through a temperature sensor; when S>Sum_Limit represents the wave skipping, where Sum_limit is the time and wave skipping detection threshold, typically set to 0.4 to 0.8 times the excitation waveform period. Specifically, the method disclosed in Chinese Patent Publication No. CN119374677A can be used.

[0088] Preferably, step S4 includes: when a jump wave is detected in step S3, the current channel jump wave count jump_cnt is incremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call; when no jump wave is detected in step S3, the current channel jump wave count jump_cnt is decremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call.

[0089] The minimum value of the wave jump count jump_cnt is 0, and the maximum value is the counting threshold jump_fault_cnt_this.

[0090] Preferably, step S5 includes:

[0091] After incrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt with the preset value jump_state. The preset value is less than the counting threshold jump_fault_cnt_this and greater than 0. When the jump count jump_cnt is less than or equal to the preset value jump_state, output the second overall bubble condition bubble1. When the jump count jump_cnt is greater than the preset value jump_state, compare the jump count jump_cnt of all channels with the counting threshold jump_fault_cnt_this. If the jump count jump_cnt of all channels is greater than or equal to the counting threshold jump_fault_cnt_this, output the third overall bubble condition bubble2; otherwise, output the second overall bubble condition bubble1.

[0092] After decrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt of all channels with 0. If the jump count jump_cnt of all channels is equal to 0, output the first overall bubble condition bubble0; otherwise, output the second overall bubble condition bubble1.

[0093] More preferably, the preset value jump_state ranges from 4 to 16. Most preferably, the preset value is 8.

[0094] More preferably, the counting threshold jump_fault_cnt_this ranges from 16 to 64. Most preferably, the counting threshold jump_fault_cnt_this is 32.

[0095] More preferably, after outputting the second overall bubble condition bubble1, the measurement frequency is increased, that is, the time interval between two adjacent measurements is shortened. For example, originally two measurements were performed in 1 second, and the measurement sampling time (the time interval between two measurements) was 0.5 seconds; after increasing the measurement frequency, four measurements were performed in 1 second, and the measurement sampling time was 0.25 seconds.

[0096] Preferably, step S6 includes: when the first overall bubble condition is bubble0, the overall countercurrent and concurrent flow time difference. t_a is the time difference between forward and reverse flow for all audio channels. The average value of t_i; the overall countercurrent and concurrent time difference when the second overall bubble condition is bubble1. t_a is the time difference between the upstream and downstream currents of all channels whose jump counts jump_cnt are less than or equal to the preset value jump_state. The average value of t_i; the overall countercurrent and concurrent time difference when the third overall bubble condition is bubble2. t_a=0;

[0097] The time difference between countercurrent and concurrent current t_i = Tu_i - Td_i, where i is the virtual channel number.

[0098] Preferably, step S7 includes:

[0099] Step S71: Calculate the water flow velocity v = t_a*C*C / (2*L), where C is the speed of sound and L is the ultrasonic transmission distance in the direction of water flow;

[0100] Step S72: Calculate the instantaneous flow rate Q = π * D * D / 4 * v * k, where D is the pipe diameter, v is the water flow velocity, and k is the flow compensation coefficient;

[0101] Step S73: Calculate the cumulative flow Σ=Q*CT, where CT is the measurement sampling time.

[0102] Example 2:

[0103] like Figures 1 to 8As shown, this embodiment provides a water meter using the virtual multi-channel anti-bubble ultrasonic flow metering method described in Embodiment 1, comprising: a pipe section 5 and a control device. At least one pair of first transducers AT and second transducers AR are fixedly installed inside the pipe section 5, and the control device is electrically connected to the first transducers AT and the second transducers AR respectively.

[0104] Example 3:

[0105] This embodiment provides an improved water meter based on Embodiment 2. The pipe diameter of pipe segment 5 is DN15. Four virtual channels are established using a combination of transmitted waveform and received parameters through a physical channel. The interpolation phase method is used to identify whether there is wave skipping. The preset value is 8, and the counting threshold jump_fault_cnt_this is 32.

[0106] Comparative Example 1:

[0107] This comparative example uses the same structure as Example 3, the difference being the use of an existing bubble-free algorithm.

[0108] Table 1. Error Comparison between Example 1 and Comparative Example 1

[0109]

[0110] As shown in Table 1, under the same test environment, the flow error of Example 3 at various flow rates is smaller than that of Comparative Example 1. Specifically, Example 3 has an error of 100% when the flow rate is 1200 L / h, the flow rate is 100 L, and the bubble flow rate / percentage is 120 L / h and 10%. This is because in this case, the bubble error is too large, and the output parameter is designed to avoid excessive bubble error. Instead, a flow rate of 0 is used to indicate excessive gas to the staff.

[0111] The present invention has been described above by way of example, but the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A virtual multi-channel anti-bubble ultrasonic flow metering method, characterized in that, include: Step S1: Establish multiple virtual channels from the same physical channel, which includes the first transducer AT and the second transducer AR. Step S2: The second transducer AR receives and measures the signal emitted by the first transducer AT; the first transducer AT receives and measures the signal emitted by the second transducer AR. Step S3: Identify whether each virtual channel has skipped waveforms; Step S4: Update the jump count jump_cnt for each virtual channel; Step S5: Update the overall bubble status based on the jump count (jump_cnt) of all virtual channels; Step S6: Calculate the overall countercurrent and concurrent time difference based on different overall bubble conditions. t_a; Step S7: Calculate the flow rate during the sampling time; In step S1, the physical channels are established using different excitation waveform parameters and / or received signal parameters to create multiple virtual channels. The excitation waveform parameters include waveforms without phase insertion, waveforms with high phase insertion, and waveforms with low phase insertion; the received signal parameters include the first wave detection level FHL, alternating detection at different received wave intervals, zero-crossing detection of rising edge, and zero-crossing detection of falling edge. Step S1 includes: Step S11: Call the built-in first wave detection level FHL in the ultrasonic meter; Step S12: The first transducer AT and the second transducer AR respectively transmit waveforms, wherein the waveforms are at least one of no phase insertion, high phase insertion, and low phase insertion; Step S3 identifies whether each virtual channel skips waves by inserting a phase method, including the following steps: Step S31: Calculate the time difference between the zero-crossing points before and after the downstream insertion phase. Pd = Td_pos - Td_pre, calculates the zero-crossing time difference before and after the countercurrent insertion phase. Pu = Tu_pos - Tu_pre; Step S32: Calculate | Pd- Pw| and| Pu- Pw|, where Pw is the average time difference between the zero-crossing points before and after the insertion phase obtained without bubbles; Step S33: When | Pd- Pw|>P_limit and / or| Pu- If Pw|>P_limit, the virtual channel is identified as a hopping channel; otherwise, it is identified as a non-hopping channel. Here, P_limit is the hopping detection threshold, which is (0.4~0.7)*| Pj- Pw|, Pj is the average time difference between the zero-crossing points before and after the insertion phase obtained from the simulated jumping wave; Step S4 includes: when a jump wave is detected in step S3, the current channel jump wave count jump_cnt is incremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call; when no jump wave is detected in step S3, the current channel jump wave count jump_cnt is decremented by 1, and a new jump wave count jump_cnt is output for the next sampling time call. The minimum value of the wave jump count jump_cnt is 0, and the maximum value is the counting threshold jump_fault_cnt_this; Step S5 includes: After incrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt with the preset value jump_state. The preset value is less than the counting threshold jump_fault_cnt_this and greater than 0. When the jump count jump_cnt is less than or equal to the preset value jump_state, output the second overall bubble condition bubble1. When the jump count jump_cnt is greater than the preset value jump_state, compare the jump count jump_cnt of all channels with the counting threshold jump_fault_cnt_this. If the jump count jump_cnt of all channels is greater than or equal to the counting threshold jump_fault_cnt_this, output the third overall bubble condition bubble2; otherwise, output the second overall bubble condition bubble1. After decrementing the current channel jump count jump_cnt by 1, compare the jump count jump_cnt of all channels with 0. If the jump count jump_cnt of all channels is equal to 0, output the first overall bubble condition bubble0; otherwise, output the second overall bubble condition bubble1. Step S6 includes: when the first overall bubble condition is bubble0, the overall countercurrent and concurrent flow time difference. t_a is the time difference between forward and reverse flow for all audio channels. The average value of t_i; the overall countercurrent and concurrent time difference when the second overall bubble condition is bubble1. t_a is the time difference between the upstream and downstream currents of all channels when the jump count jump_cnt is less than or equal to the preset value jump_state. The average value of t_i; the overall countercurrent and concurrent time difference when the third overall bubble condition is bubble2. t_a=0; The time difference between countercurrent and concurrent current t_i = Tu_i - Td_i, where i is the virtual channel number; Step S7 includes: Step S71: Calculate the water flow velocity v = t_a*C*C / (2*L), where C is the speed of sound and L is the ultrasonic transmission distance in the direction of water flow; Step S72: Calculate the instantaneous flow rate Q = π * D * D / 4 * v * k, where D is the pipe diameter, v is the water flow velocity, and k is the flow compensation coefficient; Step S73: Calculate the cumulative flow Σ=Q*CT, where CT is the measurement sampling time.

2. The virtual multi-channel anti-bubble ultrasonic flow metering method according to claim 1, characterized in that, It also includes the following steps: Step S8: Repeat steps S2 to S7 to calculate the flow rate for each sampling time. The wave jump count jump_cnt for each sampling time is updated based on the wave jump count jump_cnt of the previous sampling time. Step S9: Add up the flow rates of all sampling times to obtain the total flow rate.

3. The virtual multi-channel anti-bubble ultrasonic flow metering method according to claim 1, characterized in that: In step S2, the second transducer AR measures the downstream flight time Td, the zero-crossing time Td_pre before the downstream insertion phase, and the zero-crossing time Td_pos after the downstream insertion phase; the first transducer AT measures the upstream flight time Tu, the zero-crossing time Tu_pre before the upstream insertion phase, and the zero-crossing time Tu_pos after the upstream insertion phase.

4. A water meter using the virtual multi-channel anti-bubble ultrasonic flow metering method as described in any one of claims 1 to 3, characterized in that, include: The pipe section (5) and the control device are provided. At least one pair of first transducers AT and second transducers AR are fixedly installed inside the pipe section (5). The control device is electrically connected to the first transducer AT and the second transducer AR respectively.

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