Metering method based on static sound velocity and circuit transmission delay calibration and gas meter

Abstract

The invention relates to the technical field of ultrasonic metering equipment and measurement, in particular to a metering method based on static sound velocity and circuit transmission delay calibration, by designing a sound path distance converter in a flow channel of an ultrasonic gas meter, especially in a square flow channel, the ultrasonic propagation sound path distance is changed under the condition that a flow channel body is not affected, and the flow path distance is changed; obtaining a double-ultrasonic sound path optimization propagation path; meanwhile, mounting and dismounting are convenient, and operation is more convenient. Meanwhile, the ultrasonic static sound velocity and the electro-acoustic-electro-acoustic conversion transmission delay, namely the circuit transmission delay are calibrated in different temperature and pressure environments, that is, performance indexes of an electronic device in different temperature and pressure environments are obtained in advance, pre-calibrated data are used for follow-up flow calculation, the measurement and calculation steps are simplified, and the measurement efficiency is improved. And the accuracy and the stability of metering results are improved. Meanwhile, the invention further provides an ultrasonic gas meter comprising the sonic path distance converter.

Description

Technical Field

[0001] This invention relates to the field of ultrasonic metrology equipment and measurement technology, specifically to a metrology method based on static sound velocity and circuit transmission delay calibration. Background Technology

[0002] The application of ultrasonic metering technology in the gas industry is booming. However, whether using the correlation method or the zero-crossing method to measure the time difference between uplink and downlink flight, problems such as low measurement accuracy and poor consistency are easily encountered. The main reason for this is that sound waves are easily affected by various factors such as temperature, pressure, gas quality, transducer installation method, and related circuit parameters during propagation in air or gas. This causes changes in sound wave velocity and amplitude, making it difficult to determine the actual static sound velocity and circuit transmission delay error. Consequently, it is difficult to determine whether the measured data is interference or normal data, affecting the measurement of uplink and downlink flight time and the calculation of the time difference, ultimately affecting the accuracy and stability of ultrasonic gas meter measurements. Summary of the Invention

[0003] The purpose of this invention is to provide a measurement method based on static sound velocity and circuit transmission delay calibration, which solves the problems of low accuracy and poor stability in measuring the uplink and downlink flight time difference of ultrasonic gas meters. In particular, for gas meters that measure the propagation of through-beam or reflective sound waves with square sound channels, the method calibrates the static sound velocity and the "electroacoustic-to-acoustic" conversion transmission delay under different temperatures and pressures, and applies the static calibration data to the calculation of the uplink and downlink flight time during actual dynamic measurement, ultimately obtaining a more accurate uplink and downlink flight time difference, thereby improving the accuracy and stability of the original measurement and calculation results.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: a measurement method based on static sound velocity and circuit transmission delay calibration is provided, comprising the following steps: S1, a sound path converter is designed in the flow channel of the ultrasonic gas meter to change the propagation sound path of the sound wave in the flow channel, forming a dual sound path optimized transmission path in the flow channel, which consists of the original sound path and the optimized sound path after the sound path converter is installed. S2, calculate the original sound path and the optimized sound path after installing the sound path converter respectively; S3, based on the calculation results of the original sound path and the optimized sound path in the previous step, calculate the static sound velocity and circuit transmission delay data; S4 measures and records static sound velocity and circuit transmission delay under different temperature and pressure environments, and performs linear fitting on multiple calibration data. S5. Under different gaseous fluid environments, based on the linear fitting curve in the previous step, the static sound velocity and / or circuit transmission delay parameters are calculated, and then the gas flow rate data of the ultrasonic gas meter is calculated to obtain the final flow rate data of the corresponding unit, thus completing the metering process.

[0005] Based on the above technical solution, the design method of the sound path converter in step S1 includes the following steps: Within the square flow channel cross section CHIU, determine the position and spacing of the sound-generating transducer and the receiving transducer, where the center of the sound-generating transducer is denoted as D, and the center of the receiving transducer is denoted as G'. Sound path converter structure design: Determine the midpoint K of UI, take the midpoint O of DK, and then draw a virtual horizontal parallel line SR through point O. Point S is located on DM, point R is located on KQ, DM⊥UI at M, QK⊥UI at K, and the incident angle ∠DKU=45°. The inclined plane NQ of the sound path converter is obtained by rotating SR counterclockwise by 15° with point O as the center. Point N is located on DM, and point Q is on the extension line of KR, that is, ∠SON=15°, thus obtaining the sound path converter of polygon ABTNQKUVW. Optimization of sound path converter structure: Point P is a point near the center of OQ, PL⊥UI at L, to prevent the inclined plane QP from blocking the return sound path F'J', cut off the quadrilateral QPLK, and obtain the final polygonal structure of the sound path converter ABTNPLUVW; The original sound path propagation path in the flow channel without the sound path converter is DK→KG'; the optimized sound path propagation path after installing the sound path converter is OF'→F'J'→J'G, where ∠DF'O=∠G'F'J' and ∠F'J'U=∠G'J'I.

[0006] Based on the above technical solution, the sound path converter structure optimization in the design method of the sound path converter in step S1 further includes: A vertical plate PP' is placed above point P to block the sound path that directly reaches the receiving transducer after diffuse reflection from point O.

[0007] Based on the above technical solution, the method for calculating the original sound path in step S2 includes the following steps: When no sound path converter is installed in the flow channel, the sound transmitting transducer and the receiving transducer are both set on the center line of the incident beam and the reflected beam, and correspond to the center point of the opposite side UI. Set the incident angle ∠DKU=45°, the transducer distance DG'=2CU, where CU is the width or depth of the square channel, then the reflection angle ∠G'KI=45°; Therefore, the sound path DK = KG' = CU, then the total sound path Lo = DK + KG' = 2 CU.

[0008] Based on the above technical solution, the method for calculating the sound path after installing the sound path converter in step S2 includes the following steps: Set the incident angle ∠DKU = 45°, the transducer distance DG' = 2CU, where CU is the width or depth of the square flow channel; DM⊥UI at M, and UCIH is the cross-section of the square flow channel, then CU = DM; Since point O is the midpoint of DK, then DO = DK= CU; Draw OE perpendicular to CH at E, then DSOE is a square. Calculate DE = DS = DM= CU; Since DE + EF' + F'G' = DG', then CU + EF' + F'G' = 2CU; Furthermore, ∠DF'O = ∠G'F'J' and ∠F'J'U = ∠G'J'I, meaning △'F'J'G' is an isosceles triangle. = = Therefore, we can conclude that G'F' = 4EF'. To be entered into the formula CU + EF' + F'G' = 2CU. EF' = (Calculation yields: ) CU; Then OF'= = = CU, F'J'=J'G'=2OF'= CU; According to the formula for calculating the total sound path Lc=DO+OF'+F'J'+J'G', the following can be obtained: Lc= CU+ CU+ CU+ CU= CU.

[0009] Based on the above technical solution, the calculation formulas for the static sound velocity and circuit transmission delay data in step S3 are as follows: After determining the original sound path and the optimized sound path, the formula for calculating the sound path is: Lc=Vs(Ttc-Td), Lo=Vs(Tto-Td); Where Lc is the optimized sound path after installing the sound path converter, Lo is the original sound path without the sound path converter, and Lo and Lc are calculated; Vs is the static sound velocity under specific operating conditions, Ttc is the flight time measured after installing the sound path converter, Tto is the flight time measured without the sound path converter, and Tto and Ttc are the actual measured values; Td is the circuit propagation delay, Td = Ts + Tr, where Ts is the time delay from the circuit excitation signal to the sound wave starting to propagate in the channel, and Tr is the reception delay from the transducer receiving the ultrasonic signal to the circuit detecting the signal; Based on the sound path calculation formula, the formulas for calculating the static sound velocity and the circuit transmission delay parameter are as follows: Vs= ;Td=Tto- ; Based on the calculation results of Lo and Lc in step S2 above, we can obtain: Vs=( CU-2 CU) = ; Td=Tto- =Tto- .

[0010] Based on the above technical solution, step S5 includes calibrating the static sound velocity and circuit transmission delay parameters in an atmospheric environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc and pressure Pc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the static sound velocity Vtc at the current temperature Tc in the temperature dimension. The formula for calculating Vtc is: Vtc = Va + Where Tc is within the temperature range of Ta-Tb, and Va and Vb are the calibrated static sound velocity values ​​at temperatures Ta and Tb, respectively. Step four, the same as step three, calculates the specific value of the static sound velocity Vpc in the pressure dimension at the current pressure Pc; Step 5: Calculate the two-dimensional calibration value Vtpc under the current temperature Tc and pressure Pc environment, i.e., Vtpc = ; Step six, the same as step three, calculates the calibration data Tdtc of the circuit propagation delay; Step 7: Calculate the gas flow velocity f in this measurement. Use ultrasonic waves that are excited in the same direction as the airflow to measure the velocity. If the measured flight time is Tc, then Lo = (Tc – Tdtc)(Vtpc + f), and calculate f = -Vtpc. Step 8: Multiply the gas flow rate f by the area of ​​the square flow channel to calculate the flow rate per unit, thus completing the metering process.

[0011] Based on the above technical solution, step S5 further includes calibrating the circuit transmission delay parameters in an unknown gaseous fluid environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the circuit propagation delay Tdtc at the current temperature Tc. Step four, calculate the gas flow velocity f measured in this study. Use bidirectional ultrasonic waves for excitation and reception. If the upward flight time is measured as Tu and the downward flight time as Td; and the static velocity of sound is set to Vs, then: Lo = (Tu – Tdtc)(Vs + f), Lo = (Td – Tdtc)(Vs - f); therefore, the calculation yields... f= = ; Step 5: Multiply the gas flow rate f by the area of ​​the square channel to calculate the flow rate per unit, thus completing the metering process.

[0012] Based on the above technical solution, the ultrasonic gas meter flow channel is a square reflective flow channel or a square opposing flow channel.

[0013] 10. A gas meter, characterized in that it comprises a sound path transducer, a square flow channel, a sound-emitting transducer, and a receiving transducer as designed in claim 2, wherein the sound-emitting transducer is disposed on one side of the square flow channel, the receiving transducer is disposed on the same side or opposite to the sound-emitting transducer, and the sound path transducer is disposed on the side of the square flow channel opposite to the sound-emitting transducer.

[0014] Based on the above technical solutions, The beneficial effects of the technical solution provided by this invention are as follows: This invention provides a metering method based on static sound velocity and circuit transmission delay calibration. By designing a sound path converter within the flow channel of an ultrasonic gas meter, especially within a square flow channel, the ultrasonic propagation path is altered without affecting the flow channel itself, resulting in an optimized dual ultrasonic path. This method also facilitates installation and disassembly, making operation more convenient. Furthermore, it calibrates the ultrasonic static sound velocity and the electroacoustic-to-acoustic conversion transmission delay (i.e., circuit transmission delay) under different temperature and pressure environments. This is equivalent to pre-obtaining the performance indicators of electronic components under different temperature and pressure conditions. The pre-calibrated data is then used for subsequent flow calculations, simplifying the measurement and calculation steps and improving the accuracy and stability of the metering results. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the original sound path of the ultrasonic wave without the sound path converter installed in this invention; Figure 2 This is the optimal sound path cross-section diagram for ultrasonic wave propagation in this invention, in which a sound path converter is installed; Figure 3 This is a schematic diagram illustrating the optimal sound path design principle for ultrasonic wave propagation with a sound path converter installed in this invention. Detailed Implementation The present invention will be further described below with reference to the accompanying drawings and embodiments: In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0016] In the description of this invention, it should be understood that the terms "left", "right", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0017] like Figures 1 to 3 As shown, a measurement method based on static sound velocity and circuit propagation delay calibration includes the following steps: S1, a sound path converter is designed in the flow channel of the ultrasonic gas meter to change the propagation sound path of the sound wave in the flow channel, forming a dual sound path optimized transmission path in the flow channel, which consists of the original sound path and the optimized sound path after the sound path converter is installed. S2, calculate the original sound path and the optimized sound path after installing the sound path converter respectively; S3, based on the calculation results of the original sound path and the optimized sound path in the previous step, calculate the static sound velocity and circuit transmission delay data; S4 measures and records static sound velocity and circuit transmission delay under different temperature and pressure environments, and performs linear fitting on multiple calibration data. S5. Under different gaseous fluid environments, based on the linear fitting curve in the previous step, the static sound velocity and / or circuit transmission delay parameters are calculated, and then the gas flow rate data of the ultrasonic gas meter is calculated to obtain the final flow rate data of the corresponding unit, thus completing the metering process.

[0018] This invention provides a metering method based on static sound velocity and circuit transmission delay calibration. By designing a sound path converter within the flow channel of an ultrasonic gas meter, especially within a square flow channel, the ultrasonic propagation path is altered without affecting the flow channel itself, resulting in an optimized dual ultrasonic path. This method also facilitates installation and disassembly, making operation more convenient. Furthermore, it calibrates the ultrasonic static sound velocity and the electroacoustic-to-acoustic conversion transmission delay (i.e., circuit transmission delay) under different temperature and pressure environments. This is equivalent to pre-obtaining the performance indicators of electronic components under different temperature and pressure conditions. The pre-calibrated data is then used for subsequent flow calculations, simplifying the measurement and calculation steps and improving the accuracy and stability of the metering results.

[0019] Furthermore, the operating conditions of the gas meter transducer are exactly the same during factory testing and calibration as during actual use. Therefore, the data measured and calibrated under static experimental conditions can be applied to the actual measurement of the gas meter.

[0020] like Figure 2 As shown in the figure, this is the optimal sound path cross-section diagram for ultrasonic wave propagation with a sound path converter installed. The key components are the square channel (square CHIU), the transmitting transducer, the receiving transducer, and the sound path converter (polygonal ABTNPLUVW). The optimal propagation path for the sound wave is DO→OF'→F'J'→J'G'. It is called the optimal propagation path because after the sound wave is emitted from point D, it is reflected at point O on the NP slope. After reflection, the beam center propagation path is OF→FJ→JG. However, considering the selection and setting of the transducer's sound emission and reception angles and the channel length, it is best if, without the sound path converter, the beam center after reflection reaches the center G' of the receiving transducer. (See attached figure.) Figure 1The original sound path cross-section of the ultrasonic wave without the sound path converter is shown in Figure (1). Therefore, in Figure (1), when the beam center returns to CH after three reflections, point G is to the left of point G' and they do not coincide. Therefore, by adjusting the transducer installation spacing DG', the transmit / receive angles ∠G'DK and ∠DG'K, the side length CU of the square flow channel cross-section, and the slope of the sound path converter's inclined plane NP, two optimal propagation sound paths for ultrasonic transmission and reception signals can be obtained. (See attached figure.) Figure 1 As shown, the original sound path cross-section diagram of ultrasonic wave propagation without the sound path transducer is the initial reflective flow channel design. The sound wave reaches the receiving transducer after one reflection at point K on UI. Therefore, the optimal propagation path of the original sound path is DK→KG'.

[0021] If a sound path converter is installed in the flow channel, since the positions of the two transducers are fixed and cannot be adjusted, the shape design of the sound path converter becomes the key to changing the sound path. The specific design method is as follows.

[0022] Based on the above technical solutions, such as Figure 3 As shown, the design method of the sound path converter in step S1 includes the following steps: Within the square flow channel cross section CHIU, determine the position and spacing of the sound-generating transducer and the receiving transducer, where the center of the sound-generating transducer is denoted as D, and the center of the receiving transducer is denoted as G'. Sound path converter structure design: Determine the midpoint K of UI, take the midpoint O of DK, and then draw a virtual horizontal parallel line SR through point O. Point S is located on DM, point R is located on KQ, DM⊥UI at M, QK⊥UI at K, and the incident angle ∠DKU=45°. The inclined plane NQ of the sound path converter is obtained by rotating SR counterclockwise by 15° with point O as the center. Point N is located on DM, and point Q is on the extension line of KR, that is, ∠SON=15°, thus obtaining the sound path converter of polygon ABTNQKUVW. Optimization of sound path converter structure: Point P is a point near the center of OQ, PL⊥UI at L, to prevent the inclined plane QP from blocking the return sound path F'J', cut off the quadrilateral QPLK, and obtain the final polygonal structure of the sound path converter ABTNPLUVW; The original sound path propagation path in the flow channel without the sound path converter is DK→KG'; the optimized sound path propagation path after installing the sound path converter is OF'→F'J'→J'G, where ∠DF'O=∠G'F'J' and ∠F'J'U=∠G'J'I.

[0023] Based on the above technical solution, the sound path converter structure optimization in the design method of the sound path converter in step S1 further includes: A vertical plate PP' is placed above point P to block the sound path that directly reaches the receiving transducer after diffuse reflection from point O.

[0024] The reason for truncating the quadrilateral QPLK in the polygonal ABTNPLUVW of the sound path transducer (4) is to prevent the inclined plane QP from blocking the return sound path FJ or F'J'. Similarly, a vertical thin plate PP' can be added to point P' to block the sound path that directly reaches the receiving transducer (3) after diffuse reflection from point O, preventing small signals from being received prematurely by the receiving transducer and increasing measurement accuracy.

[0025] According to the ideal gas theory, the speed of sound is v = Where γ is the specific heat ratio, R is the universal gas constant, T is the absolute temperature, and M is the molar mass of the gas. The static sound velocity calibrated under different temperatures reflects, to some extent, the change in the same amount of molar mass caused by different pressures and gas quality changes. Therefore, the calibration data points should be selectively calibrated within the temperature, pressure, and gas quality change range during normal operation of the gas meter, and calibrated under standard conditions (20℃, 1 standard atmosphere) in an air environment. The original measurement calculation data and standard data are put together and linearly fitted to obtain calibration parameters. Finally, the calibration parameters are used to correct the actual metering calculation value to obtain a more accurate measurement calculation value to represent the metering data.

[0026] It should be noted that the linear fitting is based on known test point data, such as (x, y), to construct a function model that describes the relationship between variables x and y. Solving the function usually employs methods such as least squares to obtain the optimal parameters, which are the calibration parameters required above.

[0027] On the other hand, aside from the interference and distortion of electrical signals, the main influencing factor of the "electroacoustic-to-acoustic" conversion transmission delay time, i.e., the circuit transmission delay, is the operating temperature. Therefore, the circuit transmission delay Td calibrated at a certain temperature can be directly used in subsequent actual dynamic measurement calculations.

[0028] Therefore, the structural design adjustment calculation of the two ultrasonic path lengths and how to apply the static calibration data to the actual dynamic measurement calculations become the core key of this invention, as described in detail below: Based on the above technical solution, the method for calculating the original sound path in step S2 includes the following steps: When no sound path converter is installed in the flow channel, the sound transmitting transducer and the receiving transducer are both set on the center line of the incident beam and the reflected beam, and correspond to the center point of the opposite side UI. Set the incident angle ∠DKU=45°, the transducer distance DG'=2CU, where CU is the width or depth of the square channel, then the reflection angle ∠G'KI=45°; Therefore, the sound path DK = KG' = CU, then the total sound path Lo = DK + KG' = 2 CU.

[0029] To achieve better reception, the transceiver can be designed to be placed on the center line of the incident beam and the reflected beam, directly facing the center point K of the opposite side UI. In this way, after the excitation wave of the sound-emitting transceiver is reflected, the center point of the reflected beam reaches the receiving transceiver, which is the optimal original sound path propagation path.

[0030] Based on the above technical solution, the method for calculating the sound path after installing the sound path converter in step S2 includes the following steps: Set the incident angle ∠DKU = 45°, the transducer distance DG' = 2CU, where CU is the width or depth of the square flow channel; DM⊥UI at M, and UCIH is the cross-section of the square flow channel, then CU = DM; Since point O is the midpoint of DK, then DO = DK= CU; Draw OE perpendicular to CH at E, then DSOE is a square. Calculate DE = DS = DM= CU; Since DE + EF' + F'G' = DG', then CU + EF' + F'G' = 2CU; Furthermore, ∠DF'O = ∠G'F'J' and ∠F'J'U = ∠G'J'I, meaning △'F'J'G' is an isosceles triangle. = = Therefore, we can conclude that G'F' = 4EF'. To be entered into the formula CU + EF' + F'G' = 2CU. EF' = (Calculation yields: ) CU; Then OF'= = = CU, F'J'=J'G'=2OF'= CU; According to the formula for calculating the total sound path Lc=DO+OF'+F'J'+J'G', the following can be obtained: Lc= CU+ CU+ CU+ CU= CU.

[0031] Based on the above technical solution, the calculation formulas for the static sound velocity and circuit transmission delay data in step S3 are as follows: After determining the original sound path and the optimized sound path, the formula for calculating the sound path is: Lc=Vs(Ttc-Td), Lo=Vs(Tto-Td); Where Lc is the optimized sound path after installing the sound path converter, Lo is the original sound path without the sound path converter, and Lo and Lc are calculated; Vs is the static sound velocity under specific operating conditions, Ttc is the flight time measured after installing the sound path converter, Tto is the flight time measured without the sound path converter, and Tto and Ttc are the actual measured values; Td is the circuit propagation delay, Td = Ts + Tr, where Ts is the time delay from the circuit excitation signal to the sound wave starting to propagate in the channel, and Tr is the reception delay from the transducer receiving the ultrasonic signal to the circuit detecting the signal; Based on the sound path calculation formula, the formulas for calculating the static sound velocity and the circuit transmission delay parameter are as follows: Vs= ;Td=Tto- ; Based on the calculation results of Lo and Lc in step S2 above, we can obtain: Vs=( CU-2 CU) = ; Td=Tto- =Tto- .

[0032] For ease of engineering processing, in the atmospheric environment of low-altitude areas, at -10℃... Six temperature points were selected at intervals of 10°C within a 40°C range. While stationary, the static sound velocity Vs and circuit propagation delay Td were measured and recorded, along with the atmospheric pressure P. Additionally, the flow channel was placed at 20°C, standard atmospheric pressure, and ±3 kPa for pressure data measurement and calibration at three points.

[0033] Because the static sound velocity and circuit transmission delay proposed in this invention are calibrated in an atmospheric environment, the static sound velocity and circuit transmission delay calibration data are also needed when dynamically selecting flow rate points for calibration or meter reading in an atmospheric environment. However, when measuring in an unknown environment, since it may be operating in a gas environment, the change of this parameter is mainly caused by the effect of temperature on electronic devices and is not related to the gas type. Therefore, only the circuit transmission delay calibration data is needed.

[0034] Based on the above technical solution, step S5 includes calibrating the static sound velocity and circuit transmission delay parameters in an atmospheric environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc and pressure Pc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Specifically, at -10℃ Six temperature points were selected at intervals of 10°C within a 40°C range, forming a temperature range below -10°C and -10°C. 0℃, 0℃ 10℃, 10℃ 20℃, 20℃ 30℃, 30℃ 40℃, above 40℃; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the static sound velocity Vtc at the current temperature Tc in the temperature dimension. The formula for calculating Vtc is: Vtc = Va + Where Tc is within the temperature range of Ta-Tb, and Va and Vb are the calibrated static sound velocity values ​​at temperatures Ta and Tb, respectively. Based on the sound velocity calibration data, the specific value of the static sound velocity Vtc in the temperature dimension at the current temperature Tc is linearly inferred, below -10℃ and at -10℃. The range of 0℃ is calculated and inferred from calibration data at -10℃ and 0℃; 0℃ The 30℃ range is calculated and inferred from the calibration data at 0℃ and 10℃. For temperatures of 40℃ and above, calculations are made based on calibration data from 30℃ and 40℃. For example, if the calibrated sound velocities at Tc = -3℃, -10℃, and 0℃ are Va and Vb, then... Vtc=Va+ =Va+ =

[0035] Step four, similar to step three, calculate the specific value of the static sound velocity Vpc in the pressure dimension at the current pressure Pc; the calculation formula for Vpc is similar to that for Vtc, except that the temperature parameter in Vtc is replaced with the pressure parameter.

[0036] Step 5: Calculate the two-dimensional calibration value Vtpc under the current temperature Tc and pressure Pc environment, i.e., Vtpc = ; Step six, the same as step three, calculates the calibration data Tdtc of the circuit propagation delay; Step 7: Calculate the gas flow velocity f in this measurement. Use ultrasonic waves that are excited in the same direction as the airflow to measure the flow. If the measured flight time is Tc, then Lo = (Tc – Tdtc)(Vtpc + f), and calculate f = -Vtpc.

[0037] Step 8: Multiply the gas flow rate f by the area of ​​the square flow channel to calculate the flow rate per unit, thus completing the metering process.

[0038] Based on the above technical solution, step S5 further includes calibrating the circuit transmission delay parameters in an unknown gaseous fluid environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Determine which range of the six calibrated temperature points the Tc value falls within: below -10℃, -10℃, etc. 0℃, 0℃ 10℃, 10℃ 20℃, 20℃ 30℃, 30℃ 40℃, above 40℃; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the circuit propagation delay Tdtc at the current temperature Tc. The calculation method is the same as that for static sound speed, and will not be repeated here.

[0039] Step four, calculate the gas flow velocity f measured in this study. Use bidirectional ultrasonic waves for excitation and reception. If the upward flight time is measured as Tu and the downward flight time as Td; and the static velocity of sound is set to Vs, then: Lo = (Tu – Tdtc)(Vs + f), Lo = (Td – Tdtc)(Vs - f); therefore, the calculation yields... f= = ; According to the calculation formulas Lo=(Tu –Tdtc)(Vs+f) and Lo=(Td –Tdtc)(Vs-f), we can obtain =Vs+f, =Vs-f; Subtracting the two equations, we get - =2f, so the gas flow rate f is calculated.

[0040] Step 5: Multiply the gas flow rate f by the area of ​​the square channel to calculate the flow rate per unit, thus completing the metering process.

[0041] Based on the above technical solution, the ultrasonic gas meter flow channel is a square reflective flow channel or a square opposing flow channel.

[0042] Preferably, the sound path converter proposed in this application can be applied not only to square reflective channels but also to square through-flow channels. The application in square reflective channels has been described in detail above. For through-flow channels, the difference is that the sound-generating transducer and the receiving transducer are installed on both sides of the channel, that is, the receiving transducer is installed at point K. In this way, two sound paths can also be adjusted for normal use.

[0043] like Figure 1 As shown, no path transducer is installed in the channel. If the incident angle ∠DKU = 45° is also selected, then the path Lo = DK = CU. (e.g.) Figure 2 As shown, a path converter is installed in the audio channel. Based on the similar algorithm described above, Lc = CU+ CU+ CU = ( + The calibration and flow rate calculation methods for the static sound velocity and "electroacoustic-to-acoustic" conversion transmission delay of the square jet channel are similar to those for the reflection channel, and will not be repeated here.

[0044] This application also provides a gas meter, including a sound path transducer, a square flow channel, a sound-generating transducer, and a receiving transducer designed as in claim 2, wherein the sound-generating transducer is disposed on one side of the square flow channel, the receiving transducer is disposed on the same side or opposite to the sound-generating transducer, and the sound path transducer is disposed in the square flow channel on the side opposite to the sound-generating transducer.

[0045] The foregoing has shown and described the basic principles and main features of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments. Therefore, the embodiments should be considered as exemplary and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of the equivalents of the claims be included within the present invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A measurement method based on static sound velocity and circuit transmission delay calibration, characterized in that, Includes the following steps: S1, a sound path converter is designed in the flow channel of the ultrasonic gas meter to change the propagation sound path of the sound wave in the flow channel, forming a dual sound path optimized transmission path in the flow channel, which consists of the original sound path and the optimized sound path after the sound path converter is installed. S2, calculate the original sound path and the optimized sound path after installing the sound path converter respectively; S3, based on the calculation results of the original sound path and the optimized sound path in the previous step, calculate the static sound velocity and circuit transmission delay data; S4 measures and records static sound velocity and circuit transmission delay under different temperature and pressure environments, and performs linear fitting on multiple calibration data. S5. Under different gaseous fluid environments, based on the linear fitting curve in the previous step, the static sound velocity and / or circuit transmission delay parameters are calculated, and then the gas flow rate data of the ultrasonic gas meter is calculated to obtain the final flow rate data of the corresponding unit, thus completing the metering process.

2. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, The design method of the sound path converter in step S1 includes the following steps: Within the square flow channel cross section CHIU, determine the position and spacing of the sound-generating transducer and the receiving transducer, where the center of the sound-generating transducer is denoted as D, and the center of the receiving transducer is denoted as G'. Sound path converter structure design: Determine the midpoint K of UI, take the midpoint O of DK, and then draw a virtual horizontal parallel line SR through point O. Point S is located on DM, point R is located on KQ, DM⊥UI at M, QK⊥UI at K, and the incident angle ∠DKU=45°. The inclined plane NQ of the sound path converter is obtained by rotating SR counterclockwise by 15° with point O as the center. Point N is located on DM, and point Q is on the extension line of KR, that is, ∠SON=15°, thus obtaining the sound path converter of polygon ABTNQKUVW. Optimization of sound path converter structure: Point P is a point near the center of OQ, PL⊥UI at L, to prevent the inclined plane QP from blocking the return sound path F'J', cut off the quadrilateral QPLK, and obtain the final polygonal structure of the sound path converter ABTNPLUVW; The original sound path propagation path in the flow channel without the sound path converter is DK→KG'; the optimized sound path propagation path after installing the sound path converter is OF'→F'J'→J'G, where ∠DF'O=∠G'F'J' and ∠F'J'U=∠G'J'I.

3. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 2, characterized in that, The sound path converter design method in step S1, which includes sound path converter structure optimization, further includes: A vertical plate PP' is placed above point P to block the sound path that directly reaches the receiving transducer after diffuse reflection from point O.

4. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, The method for calculating the original sound path in step S2 includes the following steps: When no sound path converter is installed in the flow channel, the sound transmitting transducer and the receiving transducer are both set on the center line of the incident beam and the reflected beam, and correspond to the center point of the opposite side UI. Set the incident angle ∠DKU=45°, the transducer distance DG'=2CU, where CU is the width or depth of the square channel, then the reflection angle ∠G'KI=45°; Therefore, the sound path DK = KG' = CU, then the total sound path Lo = DK + KG' = 2 CU.

5. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, The method for calculating the sound path after installing the sound path converter in step S2 includes the following steps: Set the incident angle ∠DKU = 45°, the transducer distance DG' = 2CU, where CU is the width or depth of the square flow channel; DM⊥UI at M, and UCIH is the cross-section of the square flow channel, then CU = DM; Since point O is the midpoint of DK, then DO = DK= CU; Draw OE perpendicular to CH at E, then DSOE is a square. Calculate DE = DS = DM= CU; Since DE + EF' + F'G' = DG', then CU + EF' + F'G' = 2CU; Furthermore, ∠DF'O = ∠G'F'J' and ∠F'J'U = ∠G'J'I, meaning △'F'J'G' is an isosceles triangle. = = Therefore, we can conclude that G'F' = 4EF'. To be entered into the formula CU + EF' + F'G' = 2CU. EF' = (Calculation yields: ) CU; Then OF’ = = = CU, F’J’ = J’G’ = 2OF’ = CU; According to the formula for calculating the total sound path Lc=DO+OF'+F'J'+J'G', the following can be obtained: Lc= WITH+ WITH+ WITH+ WITH= WITH.

6. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, The formulas for calculating the static sound velocity and circuit transmission delay data in step S3 are as follows: After determining the original sound path and the optimized sound path, the formula for calculating the sound path is: Lc=Vs(Ttc-Td), Lo=Vs(Tto-Td); Where Lc is the optimized sound path after installing the sound path converter, Lo is the original sound path without the sound path converter, and Lo and Lc are calculated; Vs is the static sound velocity under specific operating conditions, Ttc is the flight time measured after installing the sound path converter, Tto is the flight time measured without the sound path converter, and Tto and Ttc are the actual measured values; Td is the circuit propagation delay, Td = Ts + Tr, where Ts is the time delay from the circuit excitation signal to the sound wave starting to propagate in the channel, and Tr is the reception delay from the transducer receiving the ultrasonic signal to the circuit detecting the signal; Based on the sound path calculation formula, the formulas for calculating the static sound velocity and the circuit transmission delay parameter are as follows: Vs= ;Td=Tto- ; Based on the calculation results of Lo and Lc in step S2 above, we can obtain: Vs=( WITH -2 WITH) = ; Td=Tto- =Tto- 。 7. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, Step S5 includes calibrating the static sound velocity and circuit transmission delay parameters in an atmospheric environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc and pressure Pc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the static sound velocity Vtc at the current temperature Tc in the temperature dimension. The formula for calculating Vtc is: Vtc = Va + Where Tc is within the temperature range of Ta-Tb, and Va and Vb are the calibrated static sound velocity values ​​at temperatures Ta and Tb, respectively. Step four, the same as step three, calculates the specific value of the static sound velocity Vpc in the pressure dimension at the current pressure Pc; Step 5: Calculate the two-dimensional calibration value Vtpc under the current temperature Tc and pressure Pc environment, i.e., Vtpc = ; Step six, the same as step three, calculates the calibration data Tdtc of the circuit propagation delay; Step 7: Calculate the gas flow velocity f in this measurement. Use ultrasonic waves that are excited in the same direction as the airflow to measure the velocity. If the measured flight time is Tc, then Lo = (Tc – Tdtc)(Vtpc + f), and calculate f = -Vtpc. Step 8: Multiply the gas flow rate f by the area of ​​the square flow channel to calculate the flow rate per unit, thus completing the metering process.

8. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, Step S5 further includes calibrating the circuit transmission delay parameters in an unknown gaseous fluid environment, and calculating the flow rate of the ultrasonic gas meter in the corresponding unit based on the calibration data, including the following process: Step 1: Measure the current ambient temperature Tc; Step 2: Determine which calibration temperature point or temperature range the Tc value falls within; Step 3: Based on the linear fitting results of the calibration data in step S4, calculate the circuit propagation delay Tdtc at the current temperature Tc. Step four, calculate the gas flow velocity f measured in this study. Use bidirectional ultrasonic waves for excitation and reception. If the upward flight time is measured as Tu and the downward flight time as Td; and the static velocity of sound is set to Vs, then: Lo = (Tu – Tdtc)(Vs + f), Lo = (Td – Tdtc)(Vs - f); therefore, the calculation yields... f= = ； Step 5: Multiply the gas flow rate f by the area of ​​the square channel to calculate the flow rate per unit, thus completing the metering process.

9. The measurement method based on static sound velocity and circuit transmission delay calibration according to claim 1, characterized in that, The ultrasonic gas meter flow channel is a square reflective flow channel or a square through-flow channel.

10. A gas meter, characterized in that, It includes the sound path transducer, square flow channel, sound-emitting transducer and receiving transducer designed as in claim 2, wherein the sound-emitting transducer is disposed on one side of the square flow channel, the receiving transducer is disposed on the same side or opposite side of the sound-emitting transducer, and the sound path transducer is disposed on the side of the square flow channel opposite to the sound-emitting transducer.

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