Method and system for calculating temperature of a high precision ultrasonic transducer

Abstract

The present application belongs to the technical field of ultrasonic water meter, and particularly relates to a method and system for calculating temperature of high-precision ultrasonic transducer, which measures the transmission time of ultrasonic waves under the environment of 20 DEG C in the production calibration stage, and calculates a compensation coefficient K which can comprehensively reflect the influence of factors such as pipeline structure, assembly, water quality, water pressure and atmospheric pressure based on the deviation of the measured speed and the standard sound speed. In the subsequent temperature back calculation, the measured speed is corrected by using the compensation coefficient K. Therefore, the present application can effectively eliminate the systematic deviation introduced by external factors such as pipeline structure, assembly error, water quality, water pressure and atmospheric pressure, significantly improve the precision of water temperature back calculation based on sound speed, and control the temperature measurement precision within 1-50 DEG C to within ±0.5 DEG C.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ultrasonic water meters, and particularly relates to a method and system for calculating temperature of a high-precision ultrasonic transducer. BACKGROUND

[0002] In the technical field of ultrasonic water meters, accurate acquisition of fluid temperature is crucial for temperature compensation of flow rate. In the prior art, a common method is to use the correlation between ultrasonic propagation speed in water and temperature to deduce water temperature. However, this method faces significant technical problems in practical application: the measured ultrasonic propagation speed is comprehensively affected by various external factors such as pipe structure, assembly error, water quality difference, water pressure, and atmospheric pressure, resulting in inherent deviation from the speed-temperature relationship in standard pure water. If not compensated, this will cause a significant decrease in the accuracy of deduced water temperature, failing to meet the demand for high-precision measurement. SUMMARY

[0003] The purpose of the present application is to provide a method and system for calculating temperature of a high-precision ultrasonic transducer, which can effectively eliminate systematic deviations introduced by external factors such as pipe structure, assembly error, water quality, water pressure, and atmospheric pressure, significantly improving the accuracy of deduced water temperature based on speed, to solve the problems raised in the background.

[0004] To achieve the above purpose, the present application adopts the following technical solution: a method for calculating temperature of a high-precision ultrasonic transducer, comprising the following steps:

[0005] In the production calibration phase, an ultrasonic water meter equipped with an ultrasonic transducer is placed in a water meter calibration machine at 20℃, and a flow acquisition module is used to measure the ultrasonic transmission time in the forward and reverse water flow directions;

[0006] According to the measured forward and reverse water flow ultrasonic transmission times, the actual ultrasonic transmission time in water is calculated, and combined with the known ultrasonic transmission path length, the uncompensated ultrasonic transmission speed is obtained;

[0007] Based on the deviation of the uncompensated ultrasonic transmission speed from the speed in standard pure water, the comprehensive compensation coefficient K of the propagation path is calculated, which is used to compensate for the effects of pipe structure, assembly error, water quality, water pressure, and atmospheric pressure;

[0008] According to the temperature drift consistency of the ultrasonic transducer material, the temperature drift coefficient Ks of the transducer is obtained by pre-fitting using statistical methods, and combined with the measured start-up time at 20℃, the linear relationship of the start-up time with temperature change is calculated;

[0009] The compensation coefficient K and the linear relationship of the start-up time with temperature change are used to comprehensively compensate the ultrasonic transmission speed at different temperatures, and the water temperature is deduced.

[0010] In the terminal use, by closing the water outlet and performing the self-calibration program, the compensation coefficient K is recalculated to eliminate the influence of the water quality, atmospheric pressure and water pressure difference of the installation site on the temperature calculation accuracy.

[0011] Preferably, the flow acquisition module is composed of a CMT3001 / X chip.

[0012] Preferably, the actual transmission time T of the ultrasonic wave in water is calculated by the formula T = (UPS + DNS) / 2 - Ts, wherein UPS is the transmission time in the forward water flow direction, DNS is the transmission time in the reverse water flow direction, and Ts is the starting time of the ultrasonic transducer.

[0013] Preferably, the uncompensated ultrasonic transmission speed V is calculated by the formula V = L / T, wherein L is the ultrasonic transmission path length, and T is the actual transmission time.

[0014] Preferably, the compensated transmission speed Vcompensation is calculated by the formula Vcompensation = (1 + K) * V, wherein K is the comprehensive compensation coefficient, and V is the uncompensated transmission speed.

[0015] Preferably, the relationship between the starting time Ts of the ultrasonic transducer and the temperature is Ts = Ks * T + b, wherein Ks is the transducer temperature drift coefficient, and b is the starting time offset at 20°C.

[0016] Preferably, the temperature drift coefficient Ks of the transducer is 0.00464035.

[0017] In another aspect, the present application provides a high-precision ultrasonic transducer temperature calculation system, comprising:

[0018] an ultrasonic transducer for transmitting and receiving ultrasonic signals;

[0019] a flow acquisition module composed of a CMT3001 / X chip for measuring the ultrasonic transmission time UPS in the forward water flow direction and the ultrasonic transmission time DNS in the reverse water flow direction;

[0020] a storage unit for storing the comprehensive compensation coefficient K obtained under the 20°C calibration environment, the transducer temperature drift coefficient Ks, the starting time offset b at 20°C, and the ultrasonic transmission path length L;

[0021] a temperature calculation unit, wherein the temperature calculation unit is configured to:

[0022] calculate the actual transmission time T of the ultrasonic wave in water according to the formula T = (UPS + DNS) / 2 - Ts, and calculate the uncompensated ultrasonic transmission speed V according to the formula V = L / T;

[0023] The comprehensive compensated transmission speed Vcompensated is calculated according to the formula Vcompensated=(1+K)*V.

[0024] The current water temperature is inversely calculated according to Ts=Ks·T+b and the sound speed-temperature mapping relationship.

[0025] Preferably, the storage unit further stores a sound speed-temperature mapping relationship.

[0026] Preferably, the system further comprises a self-calibration control unit for triggering a self-calibration program when the terminal device has no water flow.

[0027] The technical effects and advantages of the present application are as follows:

[0028] In the production calibration stage, the transmission time of the ultrasonic wave is measured at 20℃ environment, and a compensation coefficient K is calculated based on the deviation of the measured speed from the standard sound speed, which can comprehensively reflect the influence of factors such as pipeline structure, assembly, water quality, water pressure and atmospheric pressure. In the subsequent temperature inverse calculation, the measured speed is corrected by using the compensation coefficient K. Therefore, the present application can effectively eliminate the systematic deviation introduced by external factors such as pipeline structure, assembly error, water quality, water pressure and atmospheric pressure, significantly improve the accuracy of water temperature inverse calculation based on sound speed, and control the temperature measurement accuracy within ±0.5℃ in the range of 1~50℃. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The flowchart of the method for calculating the temperature of the high-precision ultrasonic transducer of the present application;

[0030] Figure 2 The block diagram of the system for calculating the temperature of the high-precision ultrasonic transducer of the present application;

[0031] Figure 3 The flowchart of the method for calculating the temperature of the high-precision ultrasonic transducer of the present application;

[0032] Figure 4 The flowchart of the method for calculating the temperature of the high-precision ultrasonic transducer of the present application; DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] The application provides a high-precision ultrasonic transducer temperature calculation method as shown in the following formula: Figure 1 The method comprises the following steps:

[0035] In the production calibration stage, the ultrasonic water meter equipped with the ultrasonic transducer is placed in a water meter calibration machine at 20 DEG C, and the ultrasonic transmission time in the forward and reverse water flow directions is measured by using a flow acquisition module; high-efficiency calibration at a single standard temperature point (20 DEG C) is realized, the production process is simplified, the calibration cost and time are reduced, and a foundation is laid for subsequent elimination of the system inherent deviation by using the comprehensive compensation coefficient K.

[0036] According to the measured ultrasonic transmission time in the forward and reverse water flow directions, the actual ultrasonic transmission time in water is calculated, and the uncompensated ultrasonic transmission speed is obtained in combination with the known ultrasonic transmission path length.

[0037] The actual ultrasonic transmission time T in water is calculated by the formula T=(UPS+DNS) / 2-Ts, wherein UPS is the forward water flow transmission time, DNS is the reverse water flow transmission time, and Ts is the ultrasonic transducer starting time.

[0038] The uncompensated ultrasonic transmission speed V is calculated by the formula V=L / T, wherein L is the ultrasonic transmission path length, and T is the actual transmission time. The compensated transmission speed Vcompensation is calculated by the formula Vcompensation=(1+K)*V, wherein K is the comprehensive compensation coefficient, and V is the uncompensated transmission speed.

[0039] The ultrasonic transducer starting time Ts changes with the temperature according to the formula Ts=Ks*T+b, wherein Ks is the transducer temperature drift coefficient, and b is the starting time offset at 20 DEG C.

[0040] By introducing and accurately compensating the inherent starting time Ts of the ultrasonic transducer and the linear drift characteristic (described by Ks and b) changing with the temperature, the measurement delay error caused by the temperature drift of the transducer material itself is effectively eliminated, the accuracy of the sound speed calculation at different temperatures is significantly improved, and a key guarantee for realizing high-precision water temperature back calculation is provided.

[0041] Based on the deviation of the uncompensated ultrasonic transmission speed from the sound speed in standard pure water, the comprehensive compensation coefficient K of the propagation path is calculated, and is used for compensating the influences of the pipeline structure, assembly error, water quality, water pressure and atmospheric pressure.

[0042] By introducing the comprehensive compensation coefficient K, the systematic sound velocity deviation caused by multiple complex factors such as pipeline geometry, mechanical assembly tolerance, actual water quality composition, working water pressure, and installation site atmospheric pressure is corrected at one time, so that the sound velocity data relied on by subsequent temperature back calculation can approach the standard value in the ideal pure water environment, and the consistency and high precision of temperature measurement in cross-environment and cross-batch applications are fundamentally guaranteed.

[0043] According to the consistency of the temperature drift of the ultrasonic transducer material, the temperature drift coefficient Ks of the transducer is obtained by statistical method, and the linear relationship of the starting time changing with temperature is calculated by combining the measured starting time at 20 DEG C.

[0044] By using the consistency of the temperature drift of the transducer material, the temperature drift coefficient Ks is determined in advance by statistical method, the temperature dependence of the starting time is accurately modeled, the temperature-related delay error caused by the transducer itself is effectively separated and quantified, and reliable theoretical basis and data support are provided for dynamically compensating the error in the full-range temperature range and improving the calculation precision of sound velocity and final water temperature.

[0045] By using the compensation coefficient K and the linear relationship of the starting time changing with temperature, the ultrasonic wave transmission speed at different temperatures is comprehensively compensated, and the water temperature is back calculated; by fusing the path comprehensive compensation coefficient K and the starting time temperature drift compensation model, the system error under the double influence of external environmental factors and transducer characteristics is eliminated, the accuracy of sound velocity measurement is significantly improved, the calculation precision of water temperature based on sound velocity back calculation is within ± 0.5 DEG C in the range of 1~50 DEG C, and the demand of high-precision temperature monitoring is met.

[0046] In the terminal use, by closing the water outlet and executing the self-calibration program, the compensation coefficient K is recalculated to eliminate the influence of water quality, atmospheric pressure and water pressure difference on the temperature calculation precision; by executing the self-calibration program on the terminal device, the comprehensive compensation coefficient K is dynamically updated, the measurement deviation introduced by the difference between the actual water quality, atmospheric pressure and water pressure of the installation site and the standard environment during production calibration is effectively offset, the temperature calculation precision of the product in different geographical and working condition environments is consistent with the calibration precision when leaving the factory, and the environmental adaptability and measurement stability of the system are significantly enhanced.

[0047] On the other hand, the application provides a high-precision ultrasonic transducer temperature calculation system, as shown in Figure 2 , comprising:

[0048] An ultrasonic transducer for transmitting and receiving ultrasonic signals;

[0049] The flow acquisition module, composed of CMT3001 / X chips, is used to measure the ultrasonic transmission time UPS in the downstream direction and the ultrasonic transmission time DNS in the upstream direction.

[0050] The storage unit is used to store the comprehensive compensation coefficient K, transducer temperature drift coefficient Ks, start-up time offset b at 20℃, and ultrasonic transmission path length L obtained under the 20℃ calibration environment; the storage unit also stores the sound velocity-temperature mapping relationship.

[0051] Temperature calculation unit, the temperature calculation unit is used for:

[0052] The actual transmission time T of ultrasound in water is calculated using the formula T=(UPS+DNS) / 2–Ts, and the uncompensated transmission speed V of ultrasound is calculated using the formula V=L / T.

[0053] The transmission speed V compensation after comprehensive compensation is calculated according to the formula V compensation = (1+K)*V.

[0054] The current water temperature can be calculated by using Ts=Ks·T+b and the sound speed-temperature mapping relationship.

[0055] It also includes a self-calibration control unit, which triggers a self-calibration procedure when there is no water flow in the terminal device.

[0056] Furthermore, the aforementioned units, during execution, also implement other steps of the method for calculating temperature using a high-precision ultrasonic transducer, as follows:

[0057] Step S1: Connect the flow acquisition module (A) constructed using chips such as CMT3001 / X to the installed ultrasonic transducers (B) and (C). Then, install the ultrasonic transducers (B) and (C) into their respective positions on the ultrasonic water meter tube (D). Finally, place the fully assembled ultrasonic water meter on a 20°C water meter calibration machine for measurement and calibration.

[0058] In step S2, for example using a D15 pipe, the ultrasonic wave transmission path is L (70.9 mm). We measure the start-up time Ts of the ultrasonic transducer using a CMT3001 / X flow acquisition module (A).

[0059] Step S3, since V=L / T(3), V (transmission speed of ultrasound in water), L (transmission path of ultrasound), T (transmission time of ultrasound in water).

[0060] T = (UPS + DNS) / 2 – Ts (4), UPS (transmission time of ultrasonic waves in water with the current), DNS (transmission time of ultrasonic waves in water against the current),

[0061] dv=v-1042.3(1), where v is the transmission speed of ultrasound in pure water under one standard atmosphere;

[0062] T=2.92498e-9*dv5–8.991-7*dv4+1.0139e-4*dv3-0.0042*dv2+0.227*dv-0.2483 (2)

[0063] T (Celsius temperature value); The ultrasonic transmission speed in water at 20℃ is calculated by formula (3) and (4) and there is a deviation from the value calculated by formula (1) and (2) or Table (5). The main reasons for the deviation are the differences in pipe structure, assembly error, water quality, water pressure and atmospheric pressure. These deviations are inherent deviations. Add a compensation coefficient K to get V compensation = V + K * V = (1 + K) * V (5);

[0064] Step S4: Using statistical principles, perform approximately 50 pairs of each type of ultrasonic transducer. Following step S2, record the ultrasonic transducer start-up time Ts at different temperatures. For example, we use Jiakang Electronics' PSC1.0M014085H2AD3-B0 ultrasonic transducer. According to Ts=Ks*T+b (6)

[0065] Ks (temperature drift coefficient of the transducer) and b (start-up time of the transducer at 20℃); the temperature drift coefficient Ks of Jiakang Electronics' PSC1.0M014085H2AD3-B0 ultrasonic transducer is fitted to be 0.00464035 (note that this coefficient is only related to the ultrasonic transducer material; once the material is fixed, the deviation of this coefficient is very small). Based on this coefficient Ks, it is possible to calculate the start-up time Ts of the ultrasonic transducer at different temperatures, making it possible to use point calibration (20℃) during production.

[0066] Step S5, from formulas (3)(4)(5)(6):

[0067] V compensation = (1+K)*(L / ((UPS–DNS) / 2-(Ks*T+b))) (7), where b is the start-up time of the transducer at 20℃; after the ultrasonic transmission speed in water is compensated by formula (7), the effective temperature accuracy calculated by V compensation is controlled within ±0.5℃ in the range of 1-50℃.

[0068] In step S6, due to the location of the water meter installation, differences in local water quality, atmospheric pressure, and water pressure need to be considered. Simply close the outlet and then open the inlet; using the method described in step S3, the comprehensive compensation coefficient K for the propagation path can be calculated.

[0069] In this embodiment, the CMT3001 / X chip is used to create a flow acquisition module, and the following method is used for correction:

[0070] A. Connect the water meter pipe equipped with the ultrasonic transducer to the flow acquisition module according to... Figure 3 The connection is shown, for example, a D15 pipe, with an ultrasonic transmission path of L (70.9 mm). With this setup, we can determine the start-up time Ts of the ultrasonic transducer.

[0071] B. Calibration was performed using the one-point calibration method, with the following test conditions: 20℃ was selected as the temperature point, and the test was conducted at 0 flow rate; the water pressure was set to 0.2 MPa. Figure 3 As shown, with the outlet closed according to the S1 connection method, the ultrasonic transmission time UPS (TX~RX) and the ultrasonic transmission time DNS (RX-TX) of the water meter under 0 flow conditions were tested. Simultaneously, the water temperature was measured using a thermometer with an accuracy of 0.02℃. The altitude of the test location was 70 meters. Detailed measurement data are shown in Table (VI).

[0072] C. According to formulas (3) and (4), refer to Table (VI), which records the water meter data measured according to the S1 connection method. The relevant parameters were measured by the CMT3001 / X chip at different temperatures using a DN15 pipe ultrasonic water meter. The UPS time was found to be 50.848263 microseconds, the DNS time to be 50.848274 microseconds, and the start-up time to be 2.155227 microseconds. The actual temperature measured by the thermometer was 20.06℃. Substituting the relevant data for 20℃ into formulas (3) and (4), we get:

[0073] T=(UPS+DNS) / 2–Ts=(50.848263+50.848274) / 2-2.155227=48.6930415(us);

[0074] V = L / T = 70.9 / 48.6930415 * 1000 = 1456.06 m / s;

[0075] At a temperature of 20.06℃, the pure water transmission speed under standard atmospheric pressure was calculated using formulas (1) and (2), and compared with the data obtained from Table (V), it was approximately 1482.479 m / s, with a deviation of 26.24 m / s. This error mainly stems from the structure of the water pipe and its assembly method.

[0076] The error is caused by differences in water quality and water pressure. These deviations are inherent. Add a compensation coefficient K; K=(1482.479-1456.06) / 1456.06=0.018144 (Note that this coefficient K needs to be calibrated for each flow meter or module).

[0077] V compensation = V + K * V = (1 + K) * V (5), V compensation (the transmission speed of ultrasonic waves in water after compensation, calculated by the compensation coefficient K).

[0078] From the formula, we get =1456.06(1+0.018144)=1482.479 m / s; From Table (I), we can find the temperature to be approximately 20.06℃ by referring to the table or formula (1) and (2). Since it is a calibration point, the temperature is not deviated.

[0079] To verify the accuracy of the compensation coefficient and the test accuracy of the compensated temperature, the temperatures of 5℃, 10℃, 15℃, 25℃, 35℃, 45℃ and 50℃ were tested and recorded in Table (VI).

[0080] From Table (V), the test data at 15℃ shows that the UPS time is 51.365299us and the DNS time is 51.365299us. The actual temperature measured by the thermometer is 15℃. Substituting the relevant data for 20℃ into equations (3) and (4), we get:

[0081] T=(UPS+DNS) / 2–Ts=(51.365299+51.365299) / 2-2.155227=49.210072(us);

[0082] V = L / T = 70.9 / 49.210072 * 1000 = 1440.761964 m / s;

[0083] From formula (5) = (1+K)*V = (1+0.018144)*1440.761964 = 1466.903187 m / s;

[0084] From 1466.903187 m / s, refer to Table (V) or from formulas (1) and (2) to get 15.3℃;

[0085] Similarly, the data from Table (VI) were used to calculate the following data:

[0086]

[0087] Table (I) shows the temperature values ​​calculated after correction factor K and their error compared to the actual temperature.

[0088] The above tests revealed that the start-up time of the ultrasonic transducer was not temperature-compensated. Especially when the temperature exceeds 30℃, the error increases significantly with rising temperature. This temperature characteristic is closely related to the ultrasonic transducer material used by the manufacturer. Once the material is determined, the slope of the temperature compensation curve will remain consistent, with only slight deviations. Without compensation, the maximum calculated temperature deviation can reach 4.05℃. Therefore, temperature compensation is necessary, and the specific compensation method is as follows:

[0089] Based on chart (7) and formula (6):

[0090] For example, using Jiakang Electronics' PSC1.0M014085H2AD3-B0 ultrasonic transducer, the optimal constant ks was fitted to be 0.00464035 using engineering methods. By referring to Table (VI), the start-up time at the calibration point of 20.06℃ is 2.155227us.

[0091] From formula (6), we get: 2.155227 = 20.06 * 0.00464035 + b;

[0092] We can calculate b = 2.062141579 (µs);

[0093] As long as the start-up time of the ultrasonic transducer is measured at the calibration point as 2.155227, and the constant ks = 0.00464035, b = 2.062141579 (µs) can be calculated simultaneously.

[0094] According to formula (6), the start-up time at any temperature point can be calculated as shown in Table (II):

[0095]

[0096] Table (II) Transducer Start-up Schedule at Different Temperatures After Correcting the Start-up Time Temperature Drift Coefficient (ks)

[0097] From formulas (3)(4)(5)(6), we get:

[0098] V compensation = (1+K)*(L / ((UPS–DNS) / 2-(0.00464035*X+b)))(7);

[0099] The following table (III) shows the V compensation values ​​that can be calculated from formula (7);

[0100]

[0101] Table (III) Corrected start-up time temperature drift coefficient ks, actual ultrasonic transmission speed at different temperatures after start-up time and coefficient K.

[0102] At the same time, based on formulas (1) and (2) or by referring to table (5), we obtain table (4):

[0103]

[0104] Table (IV) Corrected Start-up Time Temperature Drift Coefficient ks, Calculated Temperature Values ​​at Different Temperatures After Start-up Time and Coefficient K, and Errors Compared with Actual Temperature Values

[0105] Since there are differences in water quality, atmospheric pressure, and water pressure at the water meter installation location, simply closing and reopening the outlet, and then correcting the compensation coefficient K using the software according to the S3 method described above, can eliminate the influence of water quality and pressure on the ultrasonic wave propagation speed, thereby ensuring the effective accuracy of temperature calculation.

[0106]

[0107] Continued from Table 5

[0108]

[0109] Table (V) Comparison of ultrasonic wave transmission speeds at different temperatures in pure water under one standard atmosphere.

[0110]

[0111] Table (VI) Relevant parameters measured by CMT3001 / X chip for ultrasonic water meters in DN15 pipelines at different temperatures

[0112] Note that the ultrasonic transmission path of the DN15 pipe is 70.9mm, and the transmission path is U-shaped.

[0113] This invention patent achieves single-point calibration (e.g., at 20°C) during the production calibration phase. Figure 3 As shown, a water meter at 20℃ is placed on the calibration platform. A flow acquisition module (A) constructed using chips such as CMT3001 / X is used to measure the start-up time of the ultrasonic transducer. The comprehensive compensation coefficient K for the propagation path is calculated using the method in step S3, effectively eliminating the influence of factors such as pipe structure, assembly errors, water quality, water pressure, and atmospheric pressure on sound velocity measurement.

[0114] Simultaneously, the method in step S4 systematically compensates for the temperature drift characteristic of the ultrasonic transducer start-up time (Ts=Ks·T+b). A mathematical model is established using the material temperature drift consistency, and corrected by combining measured data, significantly improving the accuracy of water temperature estimation based on sound velocity. Within the range of 1-50℃, the effective temperature accuracy is controlled within ±0.5℃.

[0115] Given the differences in water quality, atmospheric pressure, and water pressure in different regions, the method in step S6 ensures that the accuracy of the product's temperature measurement remains consistent with the accuracy of the production calibration. This invention patent has the advantages of low cost, simple calibration, and strong adaptability.

[0116] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating temperature using a high-precision ultrasonic transducer, characterized in that, Includes the following steps: During the production calibration phase, the ultrasonic water meter equipped with the ultrasonic transducer is placed in a water meter calibration machine at 20°C, and the ultrasonic transmission time in the direction of water flow and the direction of water flow is measured using the flow acquisition module. Based on the measured ultrasonic transmission times with and against the current, the actual transmission time of the ultrasonic wave in the water is calculated, and combined with the known ultrasonic transmission path length, the uncompensated ultrasonic transmission speed is obtained; the actual transmission time T of the ultrasonic wave in the water is calculated by the formula T=(UPS+DNS) / 2–Ts, where UPS is the transmission time with the current, DNS is the transmission time against the current, and Ts is the ultrasonic transducer start-up time. Based on the deviation between the uncompensated ultrasonic transmission speed and the sound speed in standard pure water, a comprehensive compensation coefficient K for the propagation path is calculated to compensate for the effects of pipeline structure, assembly errors, water quality, water pressure and atmospheric pressure. Based on the temperature drift consistency of the ultrasonic transducer material, the temperature drift coefficient Ks of the transducer was pre-fitted using statistical methods. Combined with the measured start-up time at 20℃, the linear relationship between start-up time and temperature was calculated. The relationship between the ultrasonic transducer start-up time Ts and temperature is: Ts = Ks·T 温度 +b, where Ks is the transducer temperature drift coefficient and b is the start-up time offset at 20℃; By utilizing the compensation coefficient K and the linear relationship between start-up time and temperature, the ultrasonic transmission speed at different temperatures is comprehensively compensated, and the water temperature is calculated in reverse. When used at the terminal, the compensation coefficient K is recalculated by closing the water outlet and executing the self-calibration procedure to eliminate the influence of differences in water quality, atmospheric pressure and water pressure at the installation site on the accuracy of temperature calculation.

2. The method for calculating temperature using a high-precision ultrasonic transducer according to claim 1, characterized in that, The traffic acquisition module is composed of CMT3001 / X chips.

3. The method for calculating temperature using a high-precision ultrasonic transducer according to claim 1, characterized in that, The uncompensated ultrasonic transmission speed V is calculated using the formula V=L / T, where L is the ultrasonic transmission path length and T is the actual transmission time.

4. The method for calculating temperature using a high-precision ultrasonic transducer according to claim 3, characterized in that, The comprehensive compensation of the transmission speed V is calculated by the formula V compensation = (1 + K) * V, where K is the comprehensive compensation coefficient and V is the uncompensated transmission speed.

5. The method for calculating temperature using a high-precision ultrasonic transducer according to claim 1, characterized in that, The temperature drift coefficient Ks of the transducer is 0.00464035.

6. A system for calculating the temperature of a high-precision ultrasonic transducer using the method described in any one of claims 1-5, characterized in that, include: An ultrasonic transducer is used to transmit and receive ultrasonic signals; The flow acquisition module, composed of CMT3001 / X chips, is used to measure the ultrasonic transmission time UPS in the downstream direction and the ultrasonic transmission time DNS in the upstream direction. The storage unit is used to store the comprehensive compensation coefficient K, the transducer temperature drift coefficient Ks, the start-up time offset b at 20℃, and the ultrasonic transmission path length L obtained under the 20℃ calibration environment. Temperature calculation unit, the temperature calculation unit is used for: The actual transmission time T of ultrasound in water is calculated using the formula T=(UPS+DNS) / 2–Ts, and the uncompensated transmission speed V of ultrasound is calculated using the formula V=L / T. The transmission speed V compensation after comprehensive compensation is calculated according to the formula V compensation = (1+K)*V. According to Ts=Ks·T 温度 The current water temperature can be obtained by inversely calculating the relationship between +b and the speed of sound-temperature mapping.

7. The system for calculating temperature using a high-precision ultrasonic transducer according to claim 6, characterized in that, The storage unit also stores the sound speed-temperature mapping relationship.

8. The system for calculating temperature using a high-precision ultrasonic transducer according to claim 6, characterized in that, The system also includes a self-calibration control unit for triggering a self-calibration procedure when there is no water flow at the terminal device.

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