A sound velocity calculation method based on ultrasonic measurement and ultrasonic water meter

Abstract

The present invention relates to the field of ultrasonic measurement technology, specifically a sound velocity calculation method based on ultrasonic measurement and an ultrasonic water meter. This sound velocity calculation method, applied to ultrasonic water meters, establishes a common model with multiple piecewise functions based on different temperature ranges to estimate the ultrasonic pulse sound velocity within the set temperature ranges. A single-meter correction model is then established to correct the common model with multiple piecewise functions. The ultrasonic water meter employs this sound velocity calculation method. The present invention has a rational design, facilitates inference and acquisition of sound velocity values, and improves the accuracy of sound velocity estimation.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic measurement, and in particular to a sound velocity calculation method based on ultrasonic measurement and an ultrasonic water meter. Background Art

[0002] In the measurement process of ultrasonic water meters, accurate measurement of the speed of sound in water at different temperatures is a very important task, which is directly related to the accuracy of flow measurement.

[0003] To save device costs and improve product competitiveness, many ultrasonic water meter manufacturers are omitting temperature sensors during production. This significantly reduces costs while also eliminating the need for additional temperature sensors, which helps reduce meter size and battery loss, ultimately extending the meter's lifespan. In these cases, inference is often used to calculate the speed of sound and obtain the instantaneous flow rate.

[0004] In addition, based on the relationship between the sound velocity and the sound path L of the ultrasonic pulse in the ultrasonic water meter, the sound velocity is calculated by inference calculation. However, due to differences in installation size and process, the actual value of the sound path L of different ultrasonic water meters will deviate from the theoretical value. The method of setting a fixed sound path L in the existing technology often brings large errors in the sound velocity calculation. In some cases, the error between the theoretical sound velocity obtained by inference calculation and the actual sound velocity can reach more than 2%, which seriously hinders the improvement of the measurement accuracy of ultrasonic water meters.

[0005] As shown in the patent document entitled "A method for measuring water flow temperature based on an ultrasonic water meter and an ultrasonic water meter" with application number 202011022714.4, the actual propagation distance of the ultrasonic wave is converted by compensating for the distance error, and the sound velocity of the ultrasonic wave is calculated based on the actual propagation time. However, in actual application, the patent's assumptions about the consistency of installation dimensions and processes cannot be achieved in practice. At the same time, since the ultrasonic wave loses part of its waveform during the oscillation process, the distance compensation value in the patent often cannot be presented as a constant quantity, but has a certain coupling relationship with the sound velocity. Therefore, there is a certain error in the calculated sound velocity.

[0006] For example, as shown in the patent document entitled "A Temperature Measurement Method Suitable for Ultrasonic Water Meters" with application number 202410448132.4, a water temperature calculation model is established in combination with the sound path length. The input of the temperature calculation model is the absolute flight time, and the output is the corrected water temperature. During the calculation process, the water temperature calculation model also uses a compensation ratio value of the designed sound path length value for calculation. The implementation of this algorithm is relatively complex. The compensation ratio coefficient referenced in the calculation remains unchanged within a fixed temperature range. If too few temperature ranges are selected, a certain error will often be introduced, and accurate sound speed output cannot be achieved. Summary of the Invention

[0007] The present invention discloses a sound velocity calculation method based on ultrasonic measurement and an ultrasonic water meter. This method solves the technical problem of low calculation accuracy in the prior art method of obtaining sound velocity by inferring using a fixed sound path L. It facilitates the inference and acquisition of sound velocity values ​​and improves the accuracy of sound velocity calculation. The technical solution adopted is as follows:

[0008] A sound velocity calculation method based on ultrasonic measurement, applied to ultrasonic water meters, comprises the following steps:

[0009] 1) Prepare multiple ultrasonic water meters of the same specifications. Preferably, multiple ultrasonic water meters are placed on a calibration table;

[0010] 2) In the set temperature range △T1, obtain the temperature values ​​t11 and t12, and obtain the corresponding sound speeds C11 and C12 by table lookup method, where C11=1468+3.68(t11-10)-0.0279(t11-10)², and C12=1468+3.68(t12-10)-0.0279(t12-10)²;

[0011] 3) Obtain the average value of the uplink and downlink times of ultrasonic pulses of multiple ultrasonic water meters within the set temperature range △T1 A function of the inverse of the speed of sound 1 / C;

[0012] 4) fitting the function to establish a common model for calculating the speed of sound;

[0013] 5) The sound velocity calculation public model is saved in the ultrasonic water meter to infer the ultrasonic pulse sound velocity of the ultrasonic water meter operating in the temperature range ΔT1.

[0014] Based on the above technical solution, the number of the ultrasonic water meters is at least 8 to 10.

[0015] On the basis of the above technical solution, the least squares method is used to fit the function to obtain a common model for calculating the speed of sound as a first-order function:

[0016] ;

[0017] k is the slope coefficient of the fitting function, and b is the intercept of the fitting function;

[0018] Based on the above technical solution, the ΔT1 is not greater than 10°C.

[0019] On the basis of the above technical solution, the average value of the up and down time of the ultrasonic pulse is obtained within the set temperature range △T2. Function 2 of the inverse of the speed of sound 1 / C;

[0020] …

[0021] In the set temperature range △TN, obtain the average value of the ultrasonic pulse up and down time The function N is the inverse of the speed of sound 1 / C;

[0022] The temperature intervals ΔT1, ΔT2 ... ΔTN are independent of each other and together form an applicable temperature interval ΔT corresponding to the ultrasonic water meter. The sound velocity calculation public model is expanded into a public model having multiple piecewise functions.

[0023] On the basis of the above technical solution, a temperature sensor is used to collect and obtain the temperature values ​​t11 and t12, and the collection accuracy of the temperature sensor is at least 0.1°C.

[0024] On the basis of the above technical solution, the temperature values ​​t11 and t12 are respectively close to the two end values ​​of the temperature interval ΔT1.

[0025] On the basis of the above technical solution, a plurality of ultrasonic water meters of the same specification are placed on a calibration table, and the temperature range ΔT1 is an integer multiple of the temperature control accuracy of the calibration table.

[0026] Based on the above technical solution, a single table correction model is established, including the following steps:

[0027] 1) Prepare a single ultrasonic water meter that operates within a set temperature range ΔT1;

[0028] 2) Obtain the current operating temperature value t1 of the single ultrasonic water meter, and obtain the sound speed C1=1468+3.68(t1-10)-0.0279(t1-10)² by looking up the table; preferably, the temperature value t1 is the middle value of the set temperature interval ΔT1;

[0029] 3) Call the public model as described above. When C=C1, the calculation is obtained ;

[0030] 4) Read the measured value SUM(T) of the ultrasonic pulse uplink and downlink time of the single ultrasonic water meter at this time;

[0031] 5) Calculate the acquisition time and correction value ;

[0032] 6) Obtain the sound velocity function of the single ultrasonic water meter after optimization, that is, the single meter correction model:

[0033] ;

[0034] Preferably, in order to reduce the randomness of the correction value △t1, several temperature values ​​t1, t2, t3...tn can be evenly spaced in the set temperature interval △T1, and the average value of the correction value at the corresponding time can be calculated. , the further optimized single table correction model is:

[0035] ;

[0036] The single-meter correction model for sound velocity calculation is stored in the ultrasonic water meter to infer the ultrasonic pulse sound velocity of the ultrasonic water meter operating in the temperature range ΔT1.

[0037] Accordingly, the corresponding optimized single-table correction model for sound velocity calculation is obtained in the set temperature range ΔT2, ΔT2...ΔTN and saved in the ultrasonic water meter.

[0038] Alternatively, the correction value △t1 of the temperature interval △T1 can be applied to the set temperature intervals △T2, △T3…△T3 to simplify the calculation.

[0039] An ultrasonic water meter, using the above-mentioned sound velocity calculation method based on ultrasonic measurement, includes a metering unit, wherein the metering unit includes:

[0040] The storage unit is used to store the sound speed calculation model of different temperature ranges; the sound speed calculation model can adopt a public model for sound speed calculation or a single table correction model.

[0041] An acquisition unit, which acquires the current measured value of the uplink and downlink time of the ultrasonic pulse of the ultrasonic water meter, so as to obtain the current sound velocity value;

[0042] A reading unit, used to read the current measured value of the uplink and downlink time difference of the ultrasonic pulse of the ultrasonic water meter;

[0043] The calculation unit measures and obtains the current instantaneous flow value.

[0044] Beneficial effects:

[0045] The present invention is rationally designed and creates a common model for calculating the speed of sound. It uses the uplink and downlink times of the ultrasonic pulse and the inverse of the speed of sound as independent and dependent variables, and forms a linear function after fitting. On the one hand, it simplifies the model, facilitates inference calculation, and is conducive to improving the measurement efficiency of ultrasonic water meters. On the other hand, it forms a common model with multiple piecewise functions for different temperature intervals, so that the common model more accurately describes the relationship between time and the inverse of the speed of sound, which is conducive to improving the accuracy of the estimated speed of sound. On the other hand, the common model uses the average value of the uplink and downlink times of the ultrasonic pulse, that is, when creating the common model, multiple water meters are used and the average value of the uplink and downlink times of the ultrasonic pulse is used. This fully considers the fact that the actual value of the sound path of the ultrasonic water meter will deviate from the theoretical value due to differences in installation size and process, which is conducive to further improving the accuracy of the estimated speed of sound. In the present invention, since ultrasonic water meters generally have a large applicable temperature range, the applicable temperature range of the ultrasonic water meter is divided into multiple temperature intervals, and the common model is expanded into a function with multiple piecewise functions, which is also conducive to ensuring the accuracy of the sound speed estimation.

[0046] In addition, the present invention fully considers the calibration efficiency issue. After the public model is established, a single meter correction model is established. When water meters are mass-produced and calibrated, only single meter correction is required, and the speed of sound in water can be obtained quickly and accurately.

[0047] The present invention fully considers the consistency of the actual value of the ultrasonic water meter sound path and the discreteness of the processing and assembly errors. On the basis of establishing a public model, a single-meter correction model is established. For each ultrasonic water meter, the difference between the time and theoretical calculation value in the public model and the actual measurement value is used as the correction value, which is beneficial to further improve the accuracy of the estimated sound velocity, and thus help to improve the measurement accuracy of instantaneous flow and cumulative flow.

[0048] That is, the invention estimates the speed of sound by establishing a reasonable public model and a single-table correction model, and combining the two. The algorithm is simple and can greatly improve the accuracy of the estimated speed of sound, which is conducive to reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present invention. Those skilled in the art can also derive other implementation drawings based on the provided drawings without inventive effort.

[0050] Figure 1 : Schematic diagram of the steps of establishing a common model with multiple piecewise functions and the corresponding single-table correction model method in the present invention;

[0051] Figure 2 : Take multiple temperature points in different temperature ranges, and use the corresponding public model to calculate the error of the sound velocity compared with the sound velocity read by the calibration table, and use the corresponding single-meter correction model to calculate the error of the sound velocity compared with the sound velocity read by the calibration table; DETAILED DESCRIPTION

[0052] As an existing technology, the main components of an ultrasonic water meter include an ultrasonic pipe section, a transducer, and a circuit section. The ultrasonic transducer is placed at a corresponding position inside the ultrasonic water meter pipe section. The ultrasonic metering chip transmits pulses of fixed amplitude through the ultrasonic transducer in the upstream and downstream directions at a certain time interval, and determines the upstream and downstream times based on the amplitude and zero crossing of the pulse. During the metering process, the ultrasonic water meter mainly calculates the instantaneous flow rate through the time difference data of the upstream and downstream, and then integrates the instantaneous flow rate through the sampling time to obtain the cumulative water consumption. In the process of calculating the instantaneous flow rate, some commonly used formulas are derived as follows:

[0053] Assume that the sound path of the ultrasonic water meter is L, the sound speed is C, and the water flow velocity is v;

[0054] The time taken to receive the signal in the uplink direction is:

[0055] ;

[0056] The time taken to receive the signal in the downlink direction is:

[0057] ;

[0058] Among them O S is the compensation value of the measurement time, which is a constant.

[0059] because , the calculation formula of the uplink and downlink propagation time difference of ultrasonic pulse can be simplified as:

[0060] ;

[0061] By transforming the above formula, we can get ;

[0062] The calculation formula of the final instantaneous flow rate in the ultrasonic pipe section ;

[0063] Since C>>V, the uplink and downlink propagation times of ultrasonic pulses are:

[0064] ;

[0065] That is, the up-and-down time of the ultrasonic pulse can be expressed as the inverse of the speed of sound / C is a function of the independent variable, specifically:

[0066] A sound velocity calculation method based on ultrasonic measurement, applied to ultrasonic water meters, comprises the following steps:

[0067] 1) Install multiple ultrasonic water meters on a calibration platform. The number of ultrasonic water meters is at least 8-10. In this embodiment, there are eight ultrasonic water meters of the same specification, labeled I, II, III, IV, V, VI, VI, VII, and VIII. The applicable temperature range of these eight ultrasonic water meters is ΔT = 50°C, for example, 0-50°C. The multiple ultrasonic water meters are placed in a static water environment to avoid complex electromagnetic interference. In other embodiments of the present invention, the number of ultrasonic water meters may be greater.

[0068] The calibration station is a prior art and will not be described in detail here. In this embodiment, the temperature control accuracy of the calibration station is 1°C.

[0069] 2) Within the set temperature range ΔT1, in this embodiment, ΔT1 is 0-10°C, including 0°C, which is an integer multiple of the temperature control accuracy of the calibration station, facilitating measurement.

[0070] 3) Acquire temperature values ​​t11 and t12. In this embodiment, temperature values ​​t11 and t12 are close to the two end values ​​of temperature interval △T1. Specifically, adjust the water flow temperature so that the temperature value around the pipes of the eight ultrasonic water meters on the calibration table is consistent with the set temperature value t11. When the temperature value around the pipes of the eight ultrasonic water meters on the calibration table reaches the set temperature value t11, collect the precise temperature reflected by the temperature sensor inside the calibration table. The temperature reflected by the temperature sensor is accurate to 0.1°C.

[0071] Afterwards, according to the temperature value t11, the corresponding sound speed C11 is obtained by looking up the table, that is, C11=1468+3.68(t11-10)-0.0279(t11-10)², and then the inverse of the sound speed at this time is obtained; among them, obtaining the corresponding sound speed by looking up the temperature value table is an existing technology and will not be repeated here.

[0072] The time and data output by the ultrasonic water meter communication line are used to obtain the average value of the uplink and downlink times of the ultrasonic pulses of the eight ultrasonic water meters at the temperature value t11. In this embodiment, the average value of the time and downlink times is expressed in nanoseconds (ns). The first data set of the average value of the uplink and downlink times of the acoustic pulses and the inverse of the speed of sound is established.

[0073] Adjust the water flow temperature again to make the temperature around the 8 ultrasonic water meter pipes on the calibration table consistent with the set temperature value t12. When the temperature around the 8 ultrasonic water meter pipes on the calibration table reaches the set temperature value t12, collect the precise temperature reflected by the temperature sensor inside the calibration table. The temperature reflected by the temperature sensor is accurate to 0.1°C.

[0074] Then, according to the temperature value of t12, the corresponding sound speed C12 is obtained by looking up the table, that is, C12=1468+3.68(t12-10)-0.0279(t12-10)², and then the inverse of the sound speed at this time is obtained;

[0075] The time and data output by the ultrasonic water meter communication line are used to obtain the average value of the uplink and downlink times of the ultrasonic pulses of the eight ultrasonic water meters at the temperature value t12. In this embodiment, the average value of the time is expressed in nanoseconds (ns), and a second data set of the average value of the uplink and downlink times of the acoustic pulses and the inverse of the speed of sound is established. In other embodiments of the present invention, more temperature values, such as t13, t14, etc., can be obtained within the set temperature interval ΔT1.

[0076] 4) Obtain the average value of the uplink and downlink times of the ultrasonic pulses of 8 ultrasonic water meters within the set temperature range △T1 A function of the inverse of the speed of sound 1 / C;

[0077] 5) Fitting the function 1 to establish a common model for calculating the speed of sound. In this embodiment, the least squares method is used to fit the function 1 to obtain a common model for calculating the speed of sound that is a first-order function:

[0078] ;

[0079] k is the slope coefficient of the fitting function, and b is the intercept of the fitting function.

[0080] In order to cover the applicable temperature range △T of ultrasonic water meter to a greater extent, in the set temperature range

[0081] In ΔT2, in this embodiment, ΔT2 is 10~20℃, including 10℃, and the above method is used to obtain the average value of the up and down time of the ultrasonic pulse Function 2 of the inverse of the speed of sound 1 / C;

[0082] …

[0083] Similarly, within the set temperature range △TN, the average value of the up and down time of the ultrasonic pulse is obtained. A function N of the inverse of the speed of sound 1 / C; in this embodiment, N=5.

[0084] In this embodiment, the temperature intervals ΔT1, ΔT2 . . . ΔTN are independent of each other and together form an applicable temperature interval ΔT corresponding to the ultrasonic water meter. In this way, a common model of multiple segments can be obtained, thereby improving applicability.

[0085] 6) The sound velocity calculation public model is saved in the ultrasonic water meter to infer the ultrasonic pulse sound velocity of the ultrasonic water meter operating in the temperature range ΔT1, ΔT2, ΔT3...ΔT5.

[0086] Further establish a single table correction model, including the following steps:

[0087] 1) Place the single ultrasonic water meter on the calibration table, such as the ultrasonic water meter marked as I. Similarly, place the single ultrasonic water meter in a normal temperature and static water environment to avoid complex electromagnetic interference. The water temperature at the water meter pipe section is within the set temperature range △T1 and the temperature remains constant.

[0088] 2) The temperature sensor inside the calibration station collects the current temperature value t1, and the sound speed at this time is obtained by looking up the table: C1 = 1468 + 3.68 (t1-10) - 0.0279 (t1-10)²;

[0089] 3) Call the corresponding public model above, when C=C1, calculate and obtain , that is, the theoretical value of the uplink and downlink time of the ultrasonic pulse of the single ultrasonic water meter;

[0090] 4) Read the measured value SUM(T) of the ultrasonic pulse uplink and downlink time of the single ultrasonic water meter at this time;

[0091] 5) Calculate the acquisition time and correction value ;

[0092] 6) Obtain the sound velocity function of the single ultrasonic water meter after optimization, that is, the single meter correction model:

[0093] ;

[0094] In this embodiment, in order to reduce the randomness of the correction value △t1, several temperature values ​​can be evenly spaced in the set temperature range △T1. 、 、 … , calculate the average value of the correction value of the corresponding time and , the further optimized single table correction model is:

[0095] ;

[0096] The correction value of the single-meter correction model for calculating the sound velocity is stored in the ultrasonic water meter's internal memory chip, allowing it to infer the ultrasonic pulse sound velocity of the single ultrasonic water meter operating within the temperature range ΔT1. Furthermore, to further simplify operations, this correction value is used for all piecewise functions, significantly reducing the workload for single-meter corrections. During factory delivery, only the common model used by the water meter needs to be corrected at room temperature, enabling rapid shipment and improving production efficiency.

[0097] In this embodiment, within the set temperature range △T1, if Figure 2 As shown, the horizontal axis is temperature, and the vertical axis is the percentage error of the estimated sound velocity compared to the value read by the calibration station. The upper blue curve shows the error of the sound velocity calculated using the corresponding single-meter correction model at multiple temperature points in different temperature ranges compared to the sound velocity read by the calibration station. The lower orange curve shows the error of the sound velocity calculated using the corresponding public model at multiple temperature points in different temperature ranges compared to the sound velocity read by the calibration station. Adjacent temperature points are connected by a straight line.

[0098] It can be seen that compared with the public model, the sound velocity error of the corrected single water meter is within 3‰, which can greatly improve the measurement accuracy of the water meter.

[0099] In other embodiments of the present invention, correction values ​​of corresponding single-meter correction models may also be obtained in set temperature intervals ΔT2, ΔT3, ..., ΔT5, and stored in an internal storage chip of the ultrasonic water meter.

[0100] An ultrasonic water meter, using the above-mentioned sound velocity calculation method based on ultrasonic measurement, includes a metering unit, which includes:

[0101] The storage unit is used to store the sound speed calculation model of different temperature ranges; the sound speed calculation model adopts a public model for sound speed calculation or a single table correction model.

[0102] An acquisition unit, which acquires the current measured value of the uplink and downlink time of the ultrasonic pulse of the ultrasonic water meter, so as to obtain the current sound velocity value;

[0103] A reading unit, used to read the current measured value of the uplink and downlink time difference of the ultrasonic pulse of the ultrasonic water meter;

[0104] The calculation unit measures and obtains the current instantaneous flow value.

[0105] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments. Any changes or modifications based on the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for calculating the speed of sound based on ultrasonic measurement, characterized in that: Applied to ultrasonic water meters, including the following steps: 1) Prepare multiple ultrasonic water meters of the same specifications; 2) In the set temperature range △T1, obtain the temperature values ​​t11 and t12, and obtain the corresponding sound speeds C11 and C12 by table lookup method, where C11=1468+3.68(t11-10)-0.0279(t11-10)², and C12=1468+3.68(t12-10)-0.0279(t12-10)²; 3) Obtain the average value of the uplink and downlink times of ultrasonic pulses of multiple ultrasonic water meters within the set temperature range △T1 A function of the inverse of the speed of sound 1 / C; 4) fitting the function to establish a common model for calculating the speed of sound; 5) The sound velocity calculation public model is saved in the ultrasonic water meter to infer the ultrasonic pulse sound velocity of the ultrasonic water meter operating within the temperature range ΔT1; 6) Further establish a single table correction model, including the following steps: S1. Prepare a single ultrasonic water meter, and operate the single ultrasonic water meter within a set temperature range ΔT1; S2. Obtain the current operating temperature value t1 of the single ultrasonic water meter, and obtain the sound speed at this time C1=1468+3.68(t1-10)-0.0279(t1-10)² by looking up the table; S3, calling the public model, when C=C1, calculate and obtain ; S4, reading the measured value SUM(T) of the uplink and downlink times of the ultrasonic pulse of the single ultrasonic water meter at this time; S5. Calculate the acquisition time and correction value ; S6. Obtain the sound velocity function of the single ultrasonic water meter after optimization, i.e., the single meter correction model: ； The single-meter correction model for sound velocity calculation is stored in the ultrasonic water meter to infer the ultrasonic pulse sound velocity of the ultrasonic water meter operating in the temperature range ΔT1.

2. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: The number of the ultrasonic water meters is at least 8 to 10.

3. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: The least squares method is used to fit the function to obtain a common model for calculating the speed of sound as a first-order function: ； k is the slope coefficient of the fitting function, and b is the intercept of the fitting function.

4. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: The ΔT1 is not greater than 10°C.

5. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: In the set temperature range △T2, obtain the average value of the ultrasonic pulse up and down time Function 2 of the inverse of the speed of sound 1 / C; … In the set temperature range △TN, obtain the average value of the ultrasonic pulse uplink and downlink time The function N is the inverse of the speed of sound 1 / C; The temperature intervals ΔT1, ΔT2 ... ΔTN are independent of each other and together form an applicable temperature interval ΔT corresponding to the ultrasonic water meter. The sound velocity calculation public model is expanded into a public model with multiple piecewise functions.

6. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: The temperature values ​​t11 and t12 are acquired by using a temperature sensor, and the acquisition accuracy of the temperature sensor is at least 0.1°C.

7. The method for calculating the speed of sound based on ultrasonic measurement according to claim 6, characterized in that: The temperature values ​​t11 and t12 are respectively close to the two end values ​​of the temperature interval ΔT1.

8. The method for calculating the speed of sound based on ultrasonic measurement according to claim 1, characterized in that: A plurality of ultrasonic water meters of the same specification are placed on a calibration table, and the temperature range ΔT1 is an integer multiple of the temperature control accuracy of the calibration table.

9. An ultrasonic water meter, characterized in that: The method for calculating the speed of sound based on ultrasonic measurement according to any one of claims 1 to 8 comprises a measuring unit, wherein the measuring unit comprises: A storage unit, used for storing sound speed calculation models in different temperature ranges; An acquisition unit, which acquires the current measured value of the uplink and downlink time of the ultrasonic pulse of the ultrasonic water meter, so as to obtain the current sound velocity value; A reading unit, used to read the current measured value of the uplink and downlink time difference of the ultrasonic pulse of the ultrasonic water meter; The calculation unit measures and obtains the current instantaneous flow value.

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