An anti-bubble flow measurement method based on ultrasonic measurement and ultrasonic water meter

Abstract

The present invention discloses an anti-bubble flow metering method based on ultrasonic measurement and an ultrasonic water meter. The anti-bubble flow metering method comprises the following steps: judging the size of the bubble ratio; when the bubble ratio is less than a set threshold value A, using a difference method to obtain the instantaneous flow; when the bubble ratio is greater than the set threshold value A, establishing a beam deviation model to measure the instantaneous flow. The ultrasonic water meter comprises a measuring pipe section, a first transducer group and a second transducer group are arranged on the same side of the measuring pipe section, and the anti-bubble flow metering method as described above is adopted. The present invention has high measurement accuracy and is conducive to simplifying the structure of the ultrasonic water meter.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic metering, and in particular to an anti-bubble flow metering method based on ultrasonic measurement and an ultrasonic water meter. Background Art

[0002] Ultrasonic waves have the characteristics of high frequency, directionality, and strong anti-interference ability, and can be used to measure the flow rate of fluids. In the design of ultrasonic water meters, the speed of water flow is determined by the time difference method of transmitting and receiving ultrasonic signals, so that the flow of water can be accurately measured. The core components of ultrasonic water meters include ultrasonic transducer groups (transducer groups include transmitters and receivers). When ultrasonic waves propagate along the direction of water flow, their propagation speed increases; conversely, when they propagate against the direction of water flow, the propagation speed slows down. By comparing the ultrasonic propagation time of downstream and upstream waves, the speed of water flow can be calculated. Based on this speed, combined with the cross-sectional area of ​​the pipe, the flow value can be obtained.

[0003] According to the measurement principle of ultrasonic water meter, the time difference between uplink and downlink is It is a very important physical quantity in the metering process, which directly determines the accuracy of the ultrasonic water meter. When there are bubbles in the pipe section, due to the inconsistency between the propagation speed of sound in gas and the speed of sound in water, the average sound speed will be reduced due to the influence of bubbles in the upstream and downstream sound channels. Due to the randomness of the bubble distribution, the time difference between the upstream and downstream cannot be accurately obtained, which brings great obstacles to the accurate calculation of the cumulative flow of the water meter.

[0004] Since the propagation characteristics of ultrasound in gas are inconsistent with those in water, in order to improve the measurement accuracy, it is generally clearly stated in the water meter installation instructions that bubbles need to be removed from the measuring pipe. Some current research and patents also revolve around such needs, focusing mainly on the elimination of bubbles and separation of bubbles in water. As shown in the patent application with application number CN202323381674.4 and the name of an ultrasonic water meter that prevents gas accumulation, bubbles in the water can be effectively separated by designing a special structure of the guide tube, and then the water flow rate is converted by ultrasonic measurement to ensure the measurement accuracy of the ultrasonic water meter. However, this design is a mechanical structure design method, which can only alleviate the influence of trace bubbles on the measurement of ultrasonic water meters, and often cannot achieve the ideal effect when the bubble flow speed is fast. For example, in the application document with application number CN202222570200.3 and the name of a portable ultrasonic water meter, by setting a defoaming component, if there are bubbles in the water flow, the spikes in the defoaming component can physically break the bubbles during the rotation process, so that there are no bubbles in the water flow and flow into the round tube, so that the accurate transmission of ultrasonic signals ensures accurate measurement. This patented design is essentially a way of eliminating bubbles using a mechanical structure design, and the structure is relatively complex and prone to failure.

[0005] In addition, there are some explorations on the processing of ultrasonic data in the case of bubble flow. As shown in the patent application with application number CN202410741925.5 and the name of a strong filtering high-precision metering smart water meter, when there are too many bubbles in the water flow, the pressure measuring component and the meter body module will monitor the water flow and there will be differences. The metering data within the difference time will be filtered to avoid excessive influence of too many bubbles on the metering of the meter body module. This is mainly to reduce errors by data filtering. When the data quality is poor, the algorithm cannot be effectively implemented. Therefore, it is urgent to design a new ultrasonic flow measurement method in the presence of bubbles. Summary of the invention

[0006] The present invention discloses an anti-bubble flow metering method based on ultrasonic measurement and an ultrasonic water meter, which solves the technical problems in the prior art that the ultrasonic water meter has a complex defoaming structure or poor defoaming effect, which is not conducive to improving the metering accuracy, and has the technical effect of high metering accuracy and being conducive to simplifying the ultrasonic water meter structure. The adopted technical solution is as follows:

[0007] An anti-bubble flow measurement method based on ultrasonic measurement comprises the following steps:

[0008] 1) comprising a first transducer group and a second transducer group, the first transducer group and the second transducer group are arranged on the same side of the measuring pipe section, and the first transducer group and the second transducer group are designed so that the amplitudes of ultrasonic pulse signals simultaneously emitted by their transmitting ends are the same;

[0009] Get the theoretical uplink time of the ultrasonic pulse of the first transducer group and theoretical downtime , and sum them: ;

[0010] Get the theoretical uplink time of the second transducer group ultrasonic pulse and theoretical downtime , and sum them: ;

[0011] Get the first transducer group ultrasonic pulse measurement uplink time and measure downlink time , and sum them: ;

[0012] Get the second transducer group ultrasonic pulse measurement uplink time and measure downlink time , sum the two: ;

[0013] 2) Calculate the uplink time measured by the first transducer group and measure downlink time time and the theoretical uplink time of the ultrasonic pulse of the first transducer group and theoretical downtime The difference between time and , ;

[0014] Calculate the second transducer group ultrasonic pulse measurement uplink time and measure downlink time time and the theoretical uplink time of the second transducer group ultrasonic pulse and theoretical downtime The difference between time and , ;

[0015] 3) When or When the absolute values ​​of are all less than the set threshold A, the instantaneous volume flow rate of water in the pipe section is measured by the time difference method. The calculation formula is:

[0016] ;

[0017] is the current propagation speed of the ultrasonic pulse in water;

[0018] D is the inner diameter of the ultrasonic water meter measuring pipe section;

[0019] Measure the time difference between the uplink and downlink propagation of ultrasonic pulses;

[0020] is the flow meter coefficient, the default value is 1;

[0021] L is the length of the uplink or downlink channel of the ultrasonic pulse;

[0022] 4) When or When the absolute value of is greater than the set threshold value A, the amplitude of the ultrasonic pulse signal emitted by the transmitting end in the first transducer group and the second transducer group is enhanced, and a beam shift method model is established:

[0023] First, bubbles are added in proportion to a pipe with a set flow rate range value, and a relationship between the bubble ratio and the amplitude signal collected by the ultrasonic pulse receiving end is established. The ultrasonic pulse receiving end is the transducer receiving end in the first transducer group or the transducer receiving end in the second transducer group. The calculation formula is:

[0024] Bubble ratio = K1*ultrasonic pulse receiving end amplitude drop ratio (Formula 1);

[0025] K1 is the bubble ratio correction coefficient, which is determined by experiments; the K1 value is obtained by calibration under different flow rate ranges;

[0026] Afterwards, in the absence of bubbles, in a pipe with a set flow rate range, a relationship between the ratio of the amplitude of the ultrasonic pulse signal received by the first transducer receiving end and the second transducer receiving end and the theoretical flow rate is established, and the calculation formula is:

[0027] Theoretical flow rate = K2*amplitude ratio of received signal (Equation 2);

[0028] K2 is the water flow rate correction coefficient, which is determined by experiments; the K2 value is obtained by calibration under different flow rate ranges;

[0029] Finally, the relationship between the actual flow rate measured by the calibration station, the bubble ratio and the theoretical flow rate is established as follows:

[0030] Actual flow rate = K3*theoretical flow rate*(1-bubble ratio);

[0031] K3 is the actual flow rate correction coefficient, and the K3 value is obtained by calibrating under different flow rate ranges.

[0032] Based on the above technical solution, the ultrasonic pulses of the first transducer group and the second transducer group are both propagated from the transmitting end to the receiving end along the W path; or the ultrasonic pulses of the first transducer group and the second transducer group are both propagated from the transmitting end to the receiving end along the V path.

[0033] On the basis of the above technical solution, after initialization before the measurement starts, the compensation value Os of the uplink propagation time and the downlink propagation time of the ultrasonic pulse in the transducer group is obtained, including: placing the measuring pipe section in still water, and closing both ends of the measuring pipe section, and obtaining the compensation value Os of the uplink and downlink propagation time of the ultrasonic pulse in the measuring pipe section: ;

[0034] is the uplink propagation time of ultrasonic pulse in still water for one transducer group;

[0035] is the downlink propagation time of ultrasonic pulse in still water for the same transducer group;

[0036] C is the theoretical propagation speed of ultrasonic pulse in water;

[0037] Right now, ;

[0038] The first transducer group and the second transducer group have the same structure and the same ultrasonic pulse uplink or downlink channel length L.

[0039] On the basis of the above technical solution, the temperature T of the water in the measuring pipe section is obtained. The theoretical propagation speed of the ultrasonic pulse in the water at temperature T is: C=1468+3.68(T-10)-0.0279(T-10)².

[0040] Based on the above technical solution, the threshold value A is set to 100ps-500ps.

[0041] On the basis of the above technical solution, or When the absolute values ​​of are all less than the set threshold value A, the amplitudes of the ultrasonic pulse signals emitted by the transmitting ends of the first transducer group and the second transducer group are the same and are between 3 and 5V; when or When the absolute value of is greater than the set threshold A, the amplitudes of the ultrasonic pulse signals emitted by the transmitting ends of the first transducer group and the second transducer group are the same and are between 8V and 12V.

[0042] On the basis of the above technical solution, or When the absolute values ​​of are all less than the set threshold A, the instantaneous flow of the first transducer group and the instantaneous flow of the second transducer group The average value is taken as the measured value, =( ) / 2.

[0043] On the basis of the above technical solution, the upward direction of the ultrasonic pulse is along the direction of water flow in the measuring pipe section, and the downward direction of the ultrasonic pulse is opposite to the direction of water flow in the measuring pipe section.

[0044] Based on the above technical solution, the first transducer group ultrasonic pulse measures the uplink time Or measure the downlink time The average value of 15 to 20 consecutive measurements is taken, and the second transducer group ultrasonic pulse measurement uplink time Or measure the downlink time , the average value of 15 to 20 consecutive measurements was taken.

[0045] An ultrasonic water meter comprises a measuring pipe section, a first transducer group and a second transducer group are arranged on the same side of the measuring pipe section, and the above-mentioned anti-bubble flow metering method is adopted.

[0046] Beneficial effect: Compared with the prior art, the present invention or When the absolute values ​​of are all less than the set threshold value A, the time difference method is used to calculate the instantaneous volume flow rate of water in the measuring pipe section. ,when or When the absolute value of is greater than the set threshold A, the amplitude of the ultrasonic pulse signal emitted by the transmitting end in the first transducer group and the second transducer group is enhanced, and a beam offset method model is established. In this way, on the one hand, the measurement method can be flexibly adopted according to the actual situation to ensure sufficient measurement accuracy. On the other hand, it can avoid increasing the calculation load of the chip when the bubble ratio is negligible, thereby improving the rationality of the design.

[0047] In the present invention, or When the absolute value of is greater than the set threshold A, a beam offset method model is established to solve the flow metering problem, which can not only avoid the use of complex defoaming mechanisms and simplify the ultrasonic water meter structure, but also reduce the production cost. In addition, in this application, by collecting enough data, the beam offset method model can be expanded to have a wider range of applications, and it can be applied even in situations where the bubble ratio is large, which solves the disadvantages of using a defoaming mechanism to improve the flow metering accuracy in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0049] Figure 1 : A schematic diagram of the structure of the ultrasonic water meter measuring pipe section in the present invention;

[0050] Figure 2 : Schematic diagram of the flow metering method steps of the present invention. DETAILED DESCRIPTION

[0051] In the prior art, the principle of using time difference to determine water flow velocity can be expressed as follows:

[0052] The time calculation formula for uplink propagation is: (1);

[0053] The time calculation formula for downlink propagation is: (2);

[0054] because , the calculation formula for the ultrasonic uplink and downlink propagation time difference can be simplified to

[0055] (3);

[0056] By transforming formula (3), we can get (4);

[0057] Volume instantaneous flow calculation formula (5);

[0058] In the formula, , —Ultrasonic wave uplink and downlink propagation time;

[0059] is the current propagation speed of the ultrasonic pulse in water;

[0060] is the flow velocity of water in the measuring pipe section;

[0061] To measure the instantaneous volume flow rate of water in the pipe section;

[0062] D is the inner diameter of the ultrasonic water meter measuring pipe section;

[0063] It is the propagation time difference between the uplink and downlink of ultrasonic wave;

[0064] is the flow meter coefficient, the default value is 1;

[0065] L is the length of the uplink or downlink channel of the ultrasonic pulse.

[0066] When there are bubbles in the measuring pipe section, the average sound velocity in the uplink and downlink sound channels will be reduced due to the influence of the bubbles, and the time difference between the uplink and downlink cannot be accurately obtained due to the randomness of the bubble distribution. , and thus cannot be accurately measured, and the flow measurement method used by the ultrasonic water meter in this application can well solve the above problems, as follows:

[0067] like Figure 1 An ultrasonic water meter is shown, comprising a measuring pipe section 5 formed by a DN15 metal copper pipe section, wherein a first transducer group and a second transducer group are arranged on the same side of the measuring pipe section 5, wherein the first transducer group comprises two first transducers, the two first transducers are mutually transmitting ends and receiving ends (1, 3), and the second transducer group comprises two second transducers, the two second transducers are mutually transmitting ends and receiving ends (2, 4).

[0068] like Figure 1As shown, the length of the ultrasonic pulse propagation upward or downward sound channel between the two first transducers in the first transducer group is the same as the length of the ultrasonic pulse propagation upward or downward sound channel between the two second transducers in the second transducer group, which is L, and extends along a W shape, and an ultrasonic pulse transmitting sheet is provided at the corresponding position of the measuring pipe section 5. In addition, in this embodiment, the ultrasonic pulse amplitude intensity emitted by the transmitting end in the first transducer group and the second transducer group is the same and is emitted synchronously. Among them, in this embodiment, the upward direction of the ultrasonic pulse is along the water flow direction in the measuring pipe section 5, and the downward direction of the ultrasonic pulse is against the water flow direction in the measuring pipe section 5.

[0069] In other embodiments of the application, the ultrasonic pulses of the first transducer group and the second transducer group are both propagated along a V path from the transmitting end to the receiving end.

[0070] In this embodiment, a temperature measurement sensor 6 is further provided in the measuring pipe section 5 for monitoring the temperature of water in the measuring pipe section 5. The temperature measurement sensor 6 can be a thermal resistor or a thermocouple. The temperature measurement sensor 6 is a prior art and will not be described in detail here.

[0071] In addition, in order to realize data transmission in time, a communication module is added to the chip circuit implementation part to send metering data to the outside at the set time interval. The communication protocol here can be selected from LORA, NB-IOT, MODBUS, etc. as needed, and verification is added to prevent communication data transmission errors.

[0072] The flow measurement method used by the ultrasonic water meter is as follows: Figure 2 shown.

[0073] An anti-bubble flow measurement method based on ultrasonic measurement comprises the following steps:

[0074] 1) After initialization, the compensation value Os of the uplink propagation time and the downlink propagation time of the ultrasonic pulse in the transducer group is obtained, specifically including: placing the measuring pipe section 5 of the ultrasonic water meter in still water, with both ends of the measuring pipe section 5 closed, and obtaining the compensation value Os of the uplink and downlink propagation time of the ultrasonic pulse in the measuring pipe section 5,

[0075] ;

[0076] is the uplink propagation time of ultrasonic pulse in still water for one transducer group;

[0077] is the downlink propagation time of ultrasonic pulse in still water for the same transducer group;

[0078] is the theoretical propagation speed of ultrasonic pulse in water.

[0079] Taking the first transducer group or the second transducer group as an example, in this embodiment, taking the first transducer group as an example, in the measuring pipe section 5 formed by the DN15 metal copper pipe section obtained through the technical manual, the uplink or downlink sound channel length L of the ultrasonic pulse propagation between the two first transducers in the first transducer group is 82.8mm, and the temperature value T indicated by the temperature measurement sensor 6 is read as 10°C. The sound speed at this time is calculated by the table lookup method and the approximate analytical expression of the relationship between ultrasonic wave and temperature, C=1468+3.68(T-10)-0.0279(T-10)², and the sound speed is 1468m / S.

[0080] Obtained through measurement of circuit board chips in ultrasonic water meters and The value of the circuit board chip is measured and the compensation value Os is obtained. It is 66981.16ns, obtained by measuring the circuit board chip It is 66981.14ns, so Os=133962.3-2*0.0828*109 / 1468=21155.76ns.

[0081] The first transducer group and the second transducer group are designed so that the amplitudes of the ultrasonic pulse signals emitted simultaneously by their transmitting ends are the same.

[0082] 2) Obtain the theoretical uplink time of the ultrasonic pulse of the first transducer group and theoretical downtime , and sum them: ;Right now, ;

[0083] Get the theoretical uplink time of the second transducer group ultrasonic pulse and theoretical downtime , and sum them: ;Right now, ;

[0084] When the water temperature is 15.9℃, the calculated value is C=1469.0m / s. =133885.508ns, which can further simplify the chip calculation load, which is beneficial to improve efficiency and reduce costs;

[0085] Get the first transducer group ultrasonic pulse measurement uplink time and measure downlink time , and sum them: ;

[0086] Get the second transducer group ultrasonic pulse measurement uplink time and measure downlink time , sum the two: .

[0087] 3) Calculate the uplink time measured by the first transducer group and measure downlink time time and the theoretical uplink time of the ultrasonic pulse of the first transducer group and theoretical downtime The difference between time and , ;

[0088] Calculate the second transducer group ultrasonic pulse measurement uplink time and measure downlink time time and the theoretical uplink time of the second transducer group ultrasonic pulse and theoretical downtime The difference between time and , .

[0089] 4) When or When the absolute values ​​of are all smaller than the set threshold A, in this embodiment, the threshold A is set to 100ps-500ps. Preferably, the threshold A is set to 100ps-200ps.

[0090] At this time, the amplitude of the ultrasonic pulse signal emitted by the transmitting end of the first transducer group and the second transducer group is the same and is between 3 and 5V; the instantaneous volume flow rate of water in the pipe section 5 is measured. The calculation formula is:

[0091] ;

[0092] — the current propagation speed of the ultrasonic pulse in water;

[0093] D — ultrasonic water meter measuring the inner diameter of pipe section 5;

[0094] —Measurement time difference between uplink and downlink propagation of ultrasonic pulse;

[0095] —Flow meter coefficient, the default is 1;

[0096] The length of the uplink or downlink channel of the ultrasonic pulse;

[0097] at this time, ≈ .

[0098] This embodiment includes a first transducer group and a second transducer group. The instantaneous flow of the first transducer group and the instantaneous flow of the second transducer group The average value is used as the measured value to further improve the measurement accuracy. =( ) / 2.

[0099] 5) When or When the absolute value of is greater than the set threshold value A, the amplitude of the ultrasonic pulse signal emitted by the transmitting end in the first transducer group and the second transducer group is enhanced, the amplitude of the ultrasonic pulse signal emitted by the transmitting end in the first transducer group and the second transducer group is the same, and is enhanced to between 8 and 12V, and a beam shift method model is established:

[0100] First, bubbles are added in proportion to a pipe with a set flow rate range value, and a relationship between the bubble ratio and the amplitude signal collected by the ultrasonic pulse receiving end is established. The ultrasonic pulse receiving end is the transducer receiving end in the first transducer group or the transducer receiving end in the second transducer group. The calculation formula is:

[0101] Bubble ratio = K1*ultrasonic pulse receiving end amplitude drop ratio (Formula 1);

[0102] K1 is the bubble ratio correction coefficient, which is determined by experiments; the K1 value is obtained by calibration under different flow rate ranges;

[0103] In this embodiment, taking the amplitude reduction ratio of the receiving end (3) in the first transducer group as an example,

[0104] When the flow rate is set in the range of 1.9-2.1m 3 / h, the K1 determined by experiment is 0.8;

[0105] When the water flow rate range is 0.5-0.6m 3 / h, the K1 determined by experiment is 0.6;

[0106] Afterwards, in the absence of bubbles, in a pipe with a set flow rate range, a relationship between the ratio of the amplitude of the ultrasonic pulse signal received by the first transducer receiving end and the second transducer receiving end and the theoretical flow rate is established, and the calculation formula is:

[0107] Theoretical flow rate = K2*amplitude ratio of received signal (Equation 2);

[0108] K2 is the water flow rate correction coefficient, which is determined by experiments; the K2 value is obtained by calibration under different flow rate ranges;

[0109] In this embodiment, taking the amplitude ratio of the signals received by the receiving end (3) in the first transducer group and the receiving end (4) of the second transducer group as an example,

[0110] When the flow rate is set in the range of 1.9-2.1m 3 / h, the K2 determined by experiment is 55.1;

[0111] When the water flow rate range is 0.5-0.6m 3 / h, the K2 determined by experiment is 40.9;

[0112] Finally, the relationship between the actual flow rate measured by the calibration station, the bubble ratio and the theoretical flow rate is established as follows:

[0113] Actual flow rate = K3*theoretical flow rate*(1-bubble ratio);

[0114] K3 is the actual flow rate correction coefficient, and the K3 value is obtained by calibrating under different flow rate ranges.

[0115] Specifically, since the value of K3 involves two variables, namely, water flow rate and bubble ratio, the K3 value formed during the calculation process will form a piecewise function of the two variables, namely, flow rate and bubble ratio. The record of the piecewise function value in the memory is as follows:

[0116] K3=0.98 2.1>Theoretical flow rate>1.9, bubble ratio≤3%;

[0117] K3=0.99 2.1>Theoretical flow rate>1.9, 3%>Bubble ratio≤6%;

[0118] In addition, to improve the measurement accuracy, the first transducer group ultrasonic pulse measurement uplink time Or measure the downlink time The average value of 15 to 20 consecutive measurements is taken, and the second transducer group ultrasonic pulse measurement uplink time Or measure the downlink time , the average value of 15 to 20 consecutive measurements was taken.

[0119] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments, and any changes or modifications made based on the present invention belong to the scope of protection claimed by the present invention.

Claims

1. A bubble-proof flow metering method based on ultrasonic measurement, characterized in that: The steps include: 1) comprising a first transducer group and a second transducer group, wherein the two transducer groups are arranged on the same side of the measuring pipe section; Get the theoretical uplink time of the ultrasonic pulse of the first transducer group and theoretical downtime , and sum them to get ; Get the theoretical uplink time of the second transducer group ultrasonic pulse and theoretical downtime , and sum them to get ; Get the first transducer group ultrasonic pulse measurement uplink time and measure downlink time , and sum them to get ; Get the second transducer group ultrasonic pulse measurement uplink time and measure downlink time , sum the two to get ; 2) Calculation , Time and , The difference between time and ;calculate , Time and , The difference between time and ; 3) When or When the absolute values ​​of are all less than the set threshold A, the instantaneous volume flow rate of water in the pipe section is measured by the time difference method. ; 4) When or When the absolute value of is greater than the set threshold value A, the amplitude of the ultrasonic pulse signal emitted by the transmitting end in the first transducer group and the second transducer group is enhanced, and a beam shift method model is established; The first transducer group and the second transducer group are designed so that the amplitudes of the ultrasonic pulse signals emitted simultaneously by their transmitting ends are the same; Measuring the instantaneous volume flow of water in a pipe section ; Establishing the beam deviation method model includes the following steps: First, bubbles are added in proportion to a pipe with a set flow rate range value, and a relationship between the bubble ratio and the amplitude signal collected by the ultrasonic pulse receiving end is established. The ultrasonic pulse receiving end is the transducer receiving end in the first transducer group or the transducer receiving end in the second transducer group. The calculation formula is: Bubble ratio = K1*ultrasonic pulse receiving end amplitude drop ratio (Formula 1); K1 is the bubble ratio correction coefficient, which is determined by experiments; the K1 value is obtained by calibration under different flow rate ranges; Afterwards, in the absence of bubbles, in a pipe with a set flow rate range, a relationship between the ratio of the amplitude of the ultrasonic pulse signal received by the first transducer receiving end and the second transducer receiving end and the theoretical flow rate is established, and the calculation formula is: Theoretical flow rate = K2*amplitude ratio of received signal (Equation 2); K2 is the water flow rate correction coefficient, which is determined by experiments; the K2 value is obtained by calibration under different flow rate ranges; Finally, the relationship between the actual flow rate measured by the calibration station, the bubble ratio and the theoretical flow rate is established as follows: Actual flow rate = K3*theoretical flow rate*(1-bubble ratio); K3 is the actual flow rate correction coefficient, and the K3 value is obtained by calibrating under different flow rate ranges; After initialization before the measurement starts, the compensation value Os of the uplink propagation time and the downlink propagation time of the ultrasonic pulse in the transducer group is obtained, including: placing the measuring pipe section in still water, and closing both ends of the measuring pipe section, and obtaining the compensation value Os of the uplink and downlink propagation time of the ultrasonic pulse in the measuring pipe section, ; is the uplink propagation time of ultrasonic pulse in still water for one transducer group; is the downlink propagation time of ultrasonic pulse in still water for the same transducer group; C is the theoretical propagation speed of ultrasonic pulse in water: 。 2. The anti-bubble flow measurement method according to claim 1, characterized in that: The ultrasonic pulses of the first transducer group and the second transducer group are both propagated from the transmitting end to the receiving end along the W path; or the ultrasonic pulses of the first transducer group and the second transducer group are both propagated from the transmitting end to the receiving end along the V path.

3. The anti-bubble flow measurement method according to claim 1, characterized in that: Obtain the temperature T of the water in the measuring pipe section. The theoretical propagation speed of the ultrasonic pulse in water at temperature T is: C=1468+3.68(T-10)-0.0279(T-10)².

4. The anti-bubble flow measurement method according to any one of claims 1 to 3, characterized in that: The threshold value A is set to be 100ps-500ps.

5. The anti-bubble flow measurement method according to claim 4, characterized in that: when or When the absolute values ​​of are all less than the set threshold value A, the amplitudes of the ultrasonic pulse signals emitted by the transmitting ends of the first transducer group and the second transducer group are the same and are between 3 and 5V; when or When the absolute value of is greater than the set threshold A, the amplitudes of the ultrasonic pulse signals emitted by the transmitting ends of the first transducer group and the second transducer group are the same and are between 8V and 12V.

6. The anti-bubble flow measurement method according to claim 5, characterized in that: when or When the absolute values ​​of are all less than the set threshold A, the instantaneous flow of the first transducer group and the instantaneous flow of the second transducer group The average value is taken as the measured value: =( ) / 2.

7. The anti-bubble flow measurement method according to claim 6, characterized in that: The upward direction of the ultrasonic pulse is along the direction of the water flow in the measuring pipe section, and the downward direction of the ultrasonic pulse is opposite to the direction of the water flow in the measuring pipe section.

8. The anti-bubble flow measurement method according to claim 7, characterized in that: The first transducer group ultrasonic pulse measurement uplink time Or measure the downlink time The average value of 15 to 20 consecutive measurements is taken, and the second transducer group ultrasonic pulse measurement uplink time Or measure the downlink time , the average value of 15 to 20 consecutive measurements was taken.

9. An ultrasonic water meter, comprising a measuring pipe section, a first transducer group and a second transducer group are arranged on the same side of the measuring pipe section, and adopts the bubble-proof flow metering method as described in any one of claims 1 to 3 and 5 to 8.

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