System, method and apparatus for automatically calibrating sound velocity of gas ultrasonic flowmeter

Abstract

A system for automatically calibrating the sound velocity of a gas ultrasonic flowmeter. The system comprises: at least one ultrasonic flowmeter (100), wherein an ultrasonic transducer (110) in each ultrasonic flowmeter (100) is used for sending and receiving sound waves in a pipeline; and a control unit (200), which comprises a satellite signal receiving unit (210), a time measurement unit (220) and a counting unit (230), wherein the satellite signal receiving unit (210) is used for generating a standard time frequency pulse, the time measurement unit (220) is used for generating a crystal oscillator frequency and calibrating a time measured by the time measurement unit (220), and the counting unit (230) is used for separately counting a crystal oscillator frequency pulse and the standard time frequency pulse. The control unit (200) is used for determining a sound velocity measurement deviation of the ultrasonic flowmeter (100), determining a deviation between the crystal oscillator frequency pulse and the standard time frequency pulse, correcting the crystal oscillator frequency on the basis of the deviation, and using a corrected crystal oscillator frequency to recalculate sound velocity. Further provided are a method for automatically calibrating the sound velocity of a gas ultrasonic flowmeter, an apparatus for automatically calibrating the sound velocity of a gas ultrasonic flowmeter, a computer device, and a computer-readable storage medium.

Description

An automatic calibration system, method and apparatus for the sound velocity of a gas ultrasonic flow meter

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202411196076.6, filed on August 28, 2024, and incorporates the entire contents of the aforementioned patent application as part of this application. Technical Field

[0003] This disclosure relates to the field of natural gas flow measurement technology, and in particular to an automatic calibration system, method and apparatus for the sound velocity of a gas ultrasonic flow meter. Background Technology

[0004] Ultrasonic gas flow meters have advantages such as wide measuring range, high accuracy, good repeatability, low pressure loss, no moving mechanical parts, high degree of informatization, and simple maintenance and use. They are increasingly widely used in the field of natural gas flow measurement.

[0005] To ensure the stable and reliable performance of ultrasonic flow meters during long-term operation, according to the verification procedure of JJG 1030-2007 "Ultrasonic Flow Meters", ultrasonic flow meters must be verified every 2 years. If the ultrasonic flow meter has a self-diagnostic function and passes the in-use inspection according to the requirements of GB / T 30500-2014 "Gas Ultrasonic Flow Meters In-Service Inspection", the verification cycle can be extended from 2 years to 6 years. When conducting in-use inspection, the performance of the ultrasonic flow meter is mainly confirmed by comparing the measured sound velocity with the theoretically calculated sound velocity and other indicators. If the deviation between the measured sound velocity and the theoretically calculated sound velocity exceeds ±0.2%, or the maximum sound velocity difference between the various channels of the ultrasonic flow meter exceeds 0.5 m / s, the sound velocity measurement of the ultrasonic flow meter is considered abnormal, and its working performance may be affected.

[0006] In general, the performance of ultrasonic flow meters is mainly confirmed through periodic verification or in-use testing. If performance changes occur during the verification or in-use testing period, they cannot be detected and addressed in a timely manner, ultimately affecting the interests of both parties in natural gas trading. Currently, the performance of ultrasonic flow meters is mainly monitored in real time by establishing a separate remote diagnostic system. However, this method requires the construction of a dedicated network and a large amount of supporting hardware, software, and human-machine interface terminals. The system construction investment cost is high, the maintenance difficulty is great, and it is not feasible for large-scale promotion and implementation. Summary of the Invention

[0007] To address the problem that the performance changes of ultrasonic flow meters cannot be known in real time during field use, and that inaccurate sound velocity measurement of ultrasonic flow meters leads to increased deviations in natural gas flow measurement results, embodiments of this disclosure provide an automatic calibration system, method, and apparatus for the sound velocity of gas ultrasonic flow meters.

[0008] This disclosure provides an automatic sound velocity calibration system for a gas ultrasonic flow meter. The system includes: at least one ultrasonic flow meter, each ultrasonic flow meter including at least one set of ultrasonic transducers, each set of ultrasonic transducers being installed opposite each other on both sides of the pipe along the pipe's extension direction, the ultrasonic transducers being used to transmit and receive sound waves within the pipe; a control unit, the control unit being connected to each set of ultrasonic flow meters (i.e., the control unit is connected to the ultrasonic flow meter through each set of ultrasonic transducers), including: a satellite signal receiving unit, a time measurement unit, and a counting unit; the satellite signal receiving unit, connected to the time measurement unit, being used to generate standard time frequency pulses; the time measurement unit including a crystal oscillator and a calibration module, the crystal oscillator being used to generate a crystal oscillator frequency, the calibration module being used to calibrate the time measured by the time measurement unit; and a counting unit, connected to the time measurement unit and the satellite signal receiving unit. The control unit is used to count crystal oscillator frequency pulses and standard time frequency pulses respectively; it is used to determine the sound velocity measurement deviation of the ultrasonic flow meter based on the ultrasonic transmission time, ultrasonic reception time and pre-calculated theoretical sound velocity of the ultrasonic transducer in the pipeline, wherein the ultrasonic transmission time and ultrasonic reception time are measured by the time measurement unit; when the sound velocity measurement deviation exceeds the preset deviation range, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is determined based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within the preset time; the crystal oscillator frequency is corrected according to the deviation, and the time length between the ultrasonic transmission time and ultrasonic reception time is remeasured using the corrected crystal oscillator frequency; the sound velocity is calculated based on the remeasured time length between the ultrasonic transmission time and ultrasonic reception time.

[0009] According to one aspect of the present disclosure, the control unit is further configured to: determine a calibration coefficient based on the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse; and use the calibration coefficient to correct the sound velocity of the ultrasonic flow meter.

[0010] This disclosure provides an automatic calibration method for the sound velocity of a gas ultrasonic flow meter. The method includes: determining the sound velocity measurement deviation of the ultrasonic flow meter based on the length of the ultrasonic wave propagation path in the pipeline, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and a pre-calculated theoretical sound velocity, wherein the ultrasonic wave transmission time and ultrasonic wave reception time are measured by a time measurement unit; when the sound velocity measurement deviation exceeds a preset deviation range, determining the deviation between the crystal oscillator frequency pulses and the standard time frequency pulses based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses generated by the satellite signal receiving unit within a preset time; correcting the crystal oscillator frequency based on the deviation, and re-measuring the time between the ultrasonic wave transmission time and the ultrasonic wave reception time using the corrected crystal oscillator frequency; and calculating the sound velocity based on the re-measured time between the ultrasonic wave transmission time and the ultrasonic wave reception time.

[0011] According to one aspect of the present disclosure, determining the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse includes: determining the difference between the number of crystal oscillator pulses generated by the time measurement unit within a preset time period and the number of standard time frequency pulses of the satellite signal receiving unit; and taking the ratio of the difference to the number of standard time frequency pulses of the satellite signal receiving unit to obtain the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse.

[0012] According to one aspect of the present disclosure, correcting the crystal oscillator frequency based on the deviation includes:

[0013] f t ′ =-E t ×f t +f t ; where f t ′ This indicates the crystal pulse frequency in the calibrated time measurement unit; f t E represents the frequency of the crystal oscillator pulse generated in the time measurement unit before calibration. t This indicates the deviation between the number of pulses at the crystal oscillator frequency and the number of pulses at the standard time frequency.

[0014] According to one aspect of the embodiments of this disclosure, when an ultrasonic flow meter includes multiple sets of ultrasonic transducers, calculating the sound velocity based on the time length between the remeasured ultrasonic transmission time and ultrasonic reception time includes determining the weighted sound velocity measured by the multiple sets of ultrasonic transducers according to the following formula: Among them, c 测 c represents the corrected speed of sound. j Let a represent the velocity of sound measured by the j-th ultrasonic transducer before calibration. j The weight represents the weight corresponding to the calculated sound velocity value of the j-th group of ultrasonic transducers, where the weight is related to the pipe cross-section path across the sound channel.

[0015] According to one aspect of the present disclosure, determining the sound velocity measurement deviation of an ultrasonic flow meter based on the length of the ultrasonic wave propagation path within the pipeline, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and a pre-calculated theoretical sound velocity includes: determining the theoretical sound velocity based on the natural gas composition, temperature, and pressure; determining the measured sound velocity based on the ultrasonic wave transmission time, the ultrasonic wave reception time, and the distance between the ultrasonic transducers; and determining the measurement deviation based on the ratio of the difference between the measured sound velocity and the theoretical sound velocity to the measured sound velocity.

[0016] This disclosure provides an automatic sound velocity calibration device for a gas ultrasonic flow meter, the device comprising:

[0017] The sound velocity deviation determination unit is used to determine the sound velocity measurement deviation of the ultrasonic flowmeter based on the length of the ultrasonic wave propagation path in the pipe, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity. The ultrasonic wave transmission time and ultrasonic wave reception time are measured by the time measurement unit. The frequency deviation determination unit is used to determine the deviation between the crystal oscillator frequency pulses and the standard time frequency pulses generated by the time measurement unit within a preset time period, based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses generated by the satellite signal receiving unit within a preset time period, when the sound velocity measurement deviation exceeds the preset deviation range. The correction unit is used to correct the crystal oscillator frequency based on the deviation, and then remeasure the time between the ultrasonic wave transmission time and the ultrasonic wave reception time using the corrected crystal oscillator frequency. The sound velocity calculation unit is used to calculate the sound velocity based on the remeasured time between the ultrasonic wave transmission time and the ultrasonic wave reception time.

[0018] This disclosure also provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements an automatic calibration method for the sound velocity of a gas ultrasonic flow meter.

[0019] This disclosure also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements an automatic calibration method for the sound velocity of a gas ultrasonic flow meter.

[0020] This disclosure enables the ultrasonic flow meter to perform self-diagnosis of its performance and automatically calibrate key parameters such as time measurement online based on the diagnostic results, ensuring that the ultrasonic flow meter is always in the best performance working state, thereby extending the calibration cycle or replacing the periodic calibration. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 is a schematic diagram of an automatic calibration system for the sound velocity of a gas ultrasonic flow meter according to an embodiment of the present disclosure.

[0023] Figure 2 is a flowchart of an automatic calibration method for the sound velocity of a gas ultrasonic flow meter according to an embodiment of the present disclosure;

[0024] Figure 3 shows a flowchart of a method for determining the deviation between a crystal oscillator frequency pulse and a standard time frequency pulse according to an embodiment of the present disclosure;

[0025] Figure 4 shows a flowchart of a method for determining the measurement deviation between the measured sound velocity and the theoretical sound velocity according to an embodiment of this disclosure;

[0026] Figure 5 is a schematic diagram of the structure of an automatic calibration device for the sound velocity of a gas ultrasonic flow meter according to an embodiment of the present disclosure.

[0027] Figure 6 shows a schematic diagram of the structure of a computer device according to an embodiment of this disclosure.

[0028] Explanation of symbols in the attached diagram: 100, Ultrasonic flow meter; 110, Ultrasonic transducer; 200, Control unit; 210, Satellite signal receiving unit; 220, Time measurement unit; 230, Counting unit; 501, Sound velocity deviation determination unit; 502, Frequency deviation determination unit; 503, Correction unit; 504, Sound velocity calculation unit; 602, Computer equipment; 604, Processor; 606, Memory; 608, Drive mechanism; 610, Input / output module; 612, Input device; 614, Output device; 616, Presentation device; 618, Graphical user interface; 620, Network interface; 622, Communication link; 624, Communication bus. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0031] This disclosure provides method operation steps as shown in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual system or device products, the methods shown in the embodiments or drawings can be executed sequentially or in parallel.

[0032] It should be noted that the automatic calibration method for the sound velocity of the ultrasonic flow meter disclosed herein can be used in the field of natural gas flow measurement, and this disclosure does not limit the application field of the automatic calibration system, method and device for the sound velocity of the ultrasonic flow meter.

[0033] Figure 1 is a schematic diagram of an automatic sound velocity calibration system for a gas ultrasonic flow meter according to an embodiment of the present disclosure. The system includes:

[0034] At least one ultrasonic flow meter 100 and a control unit 200.

[0035] At least one ultrasonic flow meter 100 is provided, each ultrasonic flow meter 100 including at least one set of ultrasonic transducers 110, each set of ultrasonic transducers 110 being mounted opposite each other on both sides of the pipeline along its extension direction. Each set of ultrasonic transducers 110 is used to transmit and receive ultrasonic signals to each other within the pipeline. It should be understood that the pipeline is a channel or conduit structure used to transport natural gas. The ultrasonic transducers, as components of the ultrasonic flow meter, are mounted on both sides or the same side of the pipeline to measure gas flow velocity and sound velocity by transmitting and receiving ultrasonic signals.

[0036] The control unit 200, connected to the pipeline, includes a satellite signal receiving unit 210, a time measurement unit 220, and a counting unit 230. The satellite signal receiving unit 210 includes a GPS or BeiDou satellite system and is connected to the time measurement unit 220 to generate standard time frequency pulses. The counting unit 230 is connected to both the time measurement unit 220 and the satellite signal receiving unit 210.

[0037] The time measurement unit 220 includes a crystal oscillator and a calibration module. Specifically, the crystal oscillator is used to generate a stable crystal frequency (i.e., the frequency of the oscillation signal output by the crystal oscillator), and the calibration module is used to calibrate the crystal frequency signal, that is, to calibrate the time measured by the time measurement unit. In this disclosure, the counting unit 230 in the control unit 200 counts the crystal frequency to measure the time interval, and when the crystal frequency deviates, the calibration module in the time measurement unit 220 is controlled to calibrate the crystal frequency.

[0038] The counting unit 230 is used to count the crystal oscillator frequency pulses and the standard time frequency pulses, respectively. The control unit 200 is used to control the ultrasonic transducer 110 to transmit and receive ultrasonic waves in the pipeline. Based on the length of the ultrasonic wave propagation path in the pipeline, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity, the sound velocity measurement deviation of the ultrasonic flow meter is determined. When the sound velocity measurement deviation exceeds the preset deviation range, the deviation between the crystal oscillator frequency pulses and the standard time frequency pulses is determined based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses generated by the satellite signal receiving unit within the preset time. The corrected crystal oscillator frequency is used to remeasure the time between the ultrasonic wave transmission time and the ultrasonic wave reception time. Based on the remeasured time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the theoretical velocity, the sound velocity is calculated.

[0039] Figure 2 is a flowchart of an automatic calibration method for the sound velocity of a gas ultrasonic flow meter according to an embodiment of this disclosure, which specifically includes the following steps:

[0040] Step 201: Determine the sound velocity measurement deviation of the ultrasonic flow meter based on the length of the ultrasonic wave propagation path in the pipeline, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity.

[0041] The ultrasonic wave transmission time and ultrasonic wave reception time are measured by the time measurement unit.

[0042] In this disclosure, one or more sets of ultrasonic transducers in a gas ultrasonic flow meter are controlled to transmit or receive ultrasonic signals within a pipeline. Typically, the ultrasonic transducers in a gas ultrasonic flow meter simultaneously transmit and receive acoustic signals. One transducer in a set transmits an ultrasonic signal from one side of the pipeline into the pipeline, while another transducer is installed on the other side of the pipeline to receive the ultrasonic signal. In this step, the propagation speed of the ultrasonic signal in the pipeline medium can be calculated based on the spacing between the installations of each set of ultrasonic transducers and the ultrasonic transmission and reception times measured by the time measurement unit.

[0043] In this embodiment, the control unit is connected to the ultrasonic flow meter, and the control unit can control the ultrasonic transducer in the ultrasonic flow meter to perform the transmission and reception of ultrasonic signals. In other embodiments of this disclosure, the ultrasonic flow meter has a timed automatic on / off function, which can realize the timed transmission and reception of ultrasonic signals.

[0044] In this step, the sound velocity measured by the ultrasonic flow meter is also only related to the propagation time of the ultrasonic signal between the ultrasonic transducers. Therefore, to a certain extent, the accuracy of the sound velocity measurement by the ultrasonic flow meter can be improved by calibrating the sound velocity measurement by measuring the accuracy of the propagation time of the ultrasonic signal between the ultrasonic flow meters.

[0045] When the fluid velocity in the pipe is not zero, the ultrasonic velocity measured by each group of ultrasonic transducers can be determined according to the following formula:

[0046] When the fluid velocity in the pipe is zero, the ultrasonic velocity can be determined using the following formula:

[0047] or

[0048] Where L represents the length of the sound wave propagation path, which is determined by the installation position of the ultrasonic transducer in the pipe; t1 represents the time for the ultrasonic signal to propagate downstream in the medium (e.g., from point A to point B); t2 represents the time for the ultrasonic signal to propagate upstream in the medium (from point B to point A).

[0049] In this step, the ultrasonic velocity calculated above is compared with the pre-calculated theoretical sound velocity to obtain the sound velocity deviation of the ultrasonic flowmeter. The theoretical sound velocity is only related to operating parameters such as the pressure, temperature, and composition of the medium. By comparing the measured sound velocity of the ultrasonic flowmeter with the theoretical sound velocity of the flowmeter under the same operating conditions, according to the technical requirements of GB / T 30500-2014 "In-service Inspection of Gas Ultrasonic Flowmeters", if the sound velocity deviation is within ±0.2%, the ultrasonic flowmeter is considered to have normal sound velocity measurement; otherwise, it is abnormal.

[0050] For example, if the ultrasonic velocity calculated using the above formula is 410.25 m / s, and the pre-calculated theoretical sound velocity is 412.28 m / s, then the sound velocity deviation of the ultrasonic flowmeter can be calculated as follows: Among them, E c This indicates the deviation between the measured speed of sound and the theoretical speed of sound; c 测 Indicates the measured ultrasonic velocity; c 算 This represents the theoretical speed of sound.

[0051] Step 202: When the sound velocity measurement deviation exceeds the preset deviation range, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is determined based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within the preset time.

[0052] In this step, the preset deviation range is used to standardize the measured ultrasonic velocity and determine whether the measured ultrasonic velocity is normal. The standard GB / T 30500-2014, "In-Service Inspection of Ultrasonic Gas Flow Meters," stipulates that the deviation between the measured sound velocity and the theoretical sound velocity of an ultrasonic flow meter should be less than ±0.2%, confirming that the ultrasonic flow meter's sound velocity measurement is normal. Based on the example in step 201, the deviation is -0.49%. Therefore, it is necessary to correct the crystal oscillator frequency using the standard time frequency pulses from the satellite signal receiving unit. Specifically, the deviation between the crystal oscillator frequency pulses and the standard time frequency pulses from the satellite signal receiving unit needs to be calculated based on the number of crystal oscillator frequency pulses from the time measurement unit and the standard time frequency pulses from the satellite signal receiving unit. The crystal oscillator frequency is then further corrected based on this deviation.

[0053] In this step, the deviation between the crystal oscillator frequency pulses and the standard time frequency pulses of the satellite signal receiving unit can be calculated using the following formula:

[0054] Among them, E t This indicates the deviation between the crystal oscillator frequency pulse generated in the time measurement unit and the standard time frequency pulse of the satellite signal receiving unit; C t Indicates the number of crystal frequency pulses generated in the time measurement unit; C s This indicates the number of standard time frequency pulses for the satellite signal receiving unit.

[0055] For example, if the number of frequency pulses generated by the crystal oscillator in the time measurement unit deviates from the number of standard time frequency pulses collected from the GPS or BeiDou satellite system within a certain time period, the frequency generated by the crystal oscillator in the time measurement unit 2 can be corrected and calibrated based on the magnitude of the deviation. The counting unit 2 can detect no less than 10 pulses per second. 8 This ensures that the frequency generated by the crystal oscillator in time measurement unit 2 meets the acquisition requirements of the standard time frequency of the GPS or BeiDou satellite system. For example, the counting unit measures 10 standard time frequency pulses received by the satellite signal receiving unit from the GPS or BeiDou satellite system within 1 second. 8 The number of crystal frequency pulses generated by the crystal oscillator of the time measurement unit was measured to be 9.5 × 10⁻⁶. 7 The deviation is calculated using the above formula. That is, the deviation between the number of crystal oscillator frequency pulses in the time measurement unit and the number of standard time frequency pulses collected by the satellite signal receiving unit is -0.5%.

[0056] Step 203: Correct the crystal oscillator frequency according to the deviation, and use the corrected crystal oscillator frequency to remeasure the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time.

[0057] Based on the deviation calculated in step 202, the calibrated crystal oscillator pulse frequency is determined, and the calibration component in the time measurement unit is used to calibrate the crystal oscillator pulse frequency generated in the time measurement unit. The calibration formula is as follows: f′ t =-E t ×f t +f t =1.005×f t ;

[0058] Where, f′ t This indicates the crystal pulse frequency in the calibrated time measurement unit; f t E represents the frequency of the crystal oscillator pulse generated in the time measurement unit before calibration. t This indicates the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse.

[0059] Step 204: Calculate the speed of sound based on the time between the remeasured ultrasonic wave transmission time and the ultrasonic wave reception time.

[0060] According to the above formula and embodiments, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse, and the calibration coefficient of the crystal oscillator frequency, are 1.005. This calibration coefficient is then further transmitted to the time measurement unit to calibrate the sound velocity measured by the ultrasonic flowmeter. Specifically, using the calibrated crystal oscillator pulse frequency in the time measurement unit, the time length between the ultrasonic wave transmission time and reception time in the ultrasonic flowmeter is remeasured, and the corresponding sound velocity is calculated according to the aforementioned sound velocity calculation formula.

[0061] When the ultrasonic flow meter includes only one set of ultrasonic transducers, the corrected measured sound velocity is expressed by the following formula:

[0062] or

[0063] Where, c′ 测 c1 represents the corrected sound velocity, c2 represents the ultrasonic velocity measured when the fluid velocity in the pipe is not zero, and c3 represents the ultrasonic velocity measured when the fluid velocity in the pipe is zero.

[0064] In this disclosure, when the ultrasonic flow meter includes multiple pairs of ultrasonic transducers, the calculation of the sound velocity based on the time length between the remeasured ultrasonic transmission time and ultrasonic reception time includes: determining the weighted sound velocity measured by multiple sets of ultrasonic transducers according to the following formula:

[0065] Where, c′ 测 c represents the corrected speed of sound. j Let a represent the velocity of sound measured by the j-th group of ultrasonic transducers before calibration. j The weight corresponding to the calculated sound velocity value of the j-th group of ultrasonic transducers is indicated by the weight, which is related to the pipe cross-section path across the sound channel.

[0066] In this embodiment of the disclosure, when the ultrasonic flow meter is designed with multiple pairs of ultrasonic transducers, each pair of transducers will measure the corresponding sound velocity values ​​c1, c2, c3, c4, c5, c6, c7, c8, c9 ... n Because each group of ultrasonic transducers is positioned differently within the ultrasonic flowmeter body, the paths of their sound channels (L, the channels or paths for sound wave transmission) across the pipe cross-section are inconsistent. Since the flow velocity of natural gas within the pipe is not uniformly distributed across the entire pipe cross-section—specifically, the flow velocity is slower near the pipe wall and faster near the pipe center—the channel length may differ when the paths across the pipe cross-section are different. Furthermore, the representativeness of the paths across the pipe interfaces for different channels varies. Therefore, the weighting of the sound velocity values ​​measured by the ultrasonic flowmeter is also different, necessitating different sound velocity weights for different groups of ultrasonic transducers. This sound velocity weight is related to the path of the sound channel across the pipe cross-section. Specifically, the more concentrated the path of the sound channel across the pipe cross-section is at the pipe center, the greater the sound velocity weight; conversely, the more concentrated the path is at the pipe edge, the smaller the corresponding sound velocity weight.

[0067] Figure 3 shows a flowchart of a method for determining the deviation between a crystal oscillator frequency pulse and a standard time frequency pulse according to an embodiment of this disclosure, which specifically includes the following steps:

[0068] Step 301: Determine the difference between the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time period.

[0069] In this step, the number of crystal pulses generated by the crystal oscillator in the time measurement unit and the number of standard time frequency pulses collected by the satellite signal receiving unit are obtained within a preset time period. The difference between the two is then calculated.

[0070] Step 302: Take the ratio of the difference to the standard time frequency pulse number of the satellite signal receiving unit to obtain the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse.

[0071] In this embodiment, if there is a deviation between the number of crystal frequency pulses generated by the crystal oscillator in the time measurement unit and the number of standard time frequency pulses collected by the satellite signal receiving unit within a certain period of time, the crystal frequency generated by the crystal oscillator in the time measurement unit can be corrected and calibrated according to the magnitude of the deviation. The counting unit can detect no less than 10 pulses per second. 8 One, to ensure that the crystal pulse frequency generated by the crystal oscillator in the time measurement unit and the standard time frequency acquisition requirements of the satellite signal receiving unit are met.

[0072] Based on the number of crystal oscillator frequency pulses and the standard time frequency pulse of the satellite signal receiving unit, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse can be expressed by the following formula:

[0073] In this embodiment of the disclosure, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is determined according to the following formula: Among them, E t This indicates the deviation between the number of crystal oscillator frequency pulses generated in the time measurement unit and the standard time frequency pulses of the satellite signal receiving unit; C t Indicates the number of crystal frequency pulses generated in the time measurement unit; C s This indicates the number of standard time frequency pulses for the satellite signal receiving unit.

[0074] This disclosure enables online verification of the sound velocity of an ultrasonic flow meter without relying on external diagnostic and monitoring systems. Based on the verification results, it automatically calibrates key time parameters for sound velocity measurement. After time calibration, the accuracy can be better than 10⁻⁸ seconds, effectively improving the accuracy of ultrasonic flow meter sound velocity measurement and ensuring that the ultrasonic flow meter sound velocity measurement is always in optimal working condition.

[0075] Figure 4 shows a flowchart of a method for determining the measurement deviation between the measured speed of sound and the theoretical speed of sound according to an embodiment of this disclosure, which specifically includes the following steps:

[0076] Step 401: Determine the theoretical speed of sound based on the composition, temperature, and pressure of the natural gas.

[0077] In this step, the theoretical speed of sound of the ultrasonic signal under the current operating state is calculated by measuring the composition of the natural gas and combining it with the temperature and pressure of the medium measured by the temperature and pressure measuring unit. The composition of the natural gas is shown in Table 1. In this embodiment, the measured temperature of the fluid in the pipeline is 18.87℃ and the pressure is 6.29MPa, therefore the calculated theoretical speed of sound is 412.28 m / s.

[0078] Table 1 Examples of Natural Gas Composition

[0079] Step 402: Determine the speed of sound based on the ultrasonic wave transmission time, ultrasonic wave reception time, and the distance between the ultrasonic transducers.

[0080] This step involves real-time online automatic calibration of the sound velocity measured by the ultrasonic flow meter by comparing the deviation between the measured sound velocity described in Figure 2 and the theoretical sound velocity.

[0081] Step 403: Determine the measurement deviation based on the ratio of the difference between the measured sound speed and the theoretical sound speed to the measured sound speed. The measurement deviation between the measured sound speed and the theoretical sound speed is determined according to the deviation calculation formula in step 201.

[0082] Figure 5 shows a schematic diagram of an automatic sound velocity calibration device for a gas ultrasonic flow meter according to an embodiment of this disclosure. The figure illustrates the basic structure of the automatic sound velocity calibration device for a gas ultrasonic flow meter. The functional units and modules can be implemented in software, or they can use general-purpose chips or specific chips to achieve automatic sound velocity calibration of the gas ultrasonic flow meter. The device specifically includes:

[0083] The sound velocity deviation determination unit 501 is used to determine the sound velocity measurement deviation of the ultrasonic flow meter based on the length of the ultrasonic wave propagation path in the pipeline, the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity. The ultrasonic wave transmission time and ultrasonic wave reception time are measured by the time measurement unit.

[0084] The frequency deviation determination unit 502 is used to determine the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time period when the sound velocity measurement deviation exceeds the preset deviation range.

[0085] The correction unit 503 is used to correct the crystal oscillator frequency according to the deviation, and to remeasure the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time using the corrected crystal oscillator frequency.

[0086] The sound velocity calculation unit 504 is used to calculate the sound velocity based on the time length between the remeasured ultrasonic wave transmission time and the ultrasonic wave reception time.

[0087] Figure 6 illustrates a computer device provided in an embodiment of this disclosure. The automatic calibration method for the sound velocity of a gas ultrasonic flow meter according to this application can be applied to a computer device. The computer device 602 may include one or more processors 604, such as one or more central processing units (CPUs), each of which can implement one or more hardware threads. The computer device 602 may also include any memory 606 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, the memory 606 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory can provide volatile or non-volatile retention of information. Further, any memory can represent a fixed or removable component of the computer device 602. In one case, when the processor 604 executes associated instructions stored in any memory or combination of memories, the computer device 602 can perform any operation of the associated instructions. The computer device 602 also includes one or more drive mechanisms 608 for interacting with any memory, such as hard disk drive mechanisms, optical disk drive mechanisms, etc.

[0088] Computer device 602 may also include an input / output module 610 (I / O) for receiving various inputs (via input device 612) and providing various outputs (via output device 614). A specific output mechanism may include a presentation device 616 and an associated graphical user interface (GUI) 618. In other embodiments, the input / output module 610 (I / O), input device 612, and output device 614 may be omitted, and the device may function solely as a computer device within a network. Computer device 602 may also include one or more network interfaces 620 for exchanging data with other devices via one or more communication links 622. One or more communication buses 624 couple the components described above together.

[0089] Communication link 622 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. Communication link 622 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0090] Corresponding to the methods in Figures 2 to 4, this disclosure also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described methods.

[0091] This disclosure also provides a computer-readable instruction, wherein when a processor executes the instruction, the program therein causes the processor to perform the method shown in Figures 2 to 4.

[0092] It should be understood that in the various embodiments of this disclosure, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this disclosure.

[0093] It should also be understood that, in the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, the character " / " in this disclosure generally indicates that the preceding and following related objects have an "or" relationship.

[0094] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this disclosure can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0095] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0096] In the embodiments provided in this disclosure, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, apparatuses, or units, or they may be electrical, mechanical, or other forms of connection.

[0097] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments of this disclosure, depending on actual needs.

[0098] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0099] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this disclosure, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this disclosure. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0100] This disclosure uses specific embodiments to illustrate the principles and implementation methods of this disclosure. The description of the above embodiments is only for the purpose of helping to understand the methods and core ideas of this disclosure. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this disclosure. Therefore, the content of this disclosure should not be construed as a limitation of this disclosure.

Claims

1. An automatic calibration system for the sound velocity of a gas ultrasonic flow meter, characterized in that, The system includes: At least one ultrasonic flow meter, the ultrasonic flow meter including at least one set of ultrasonic transducers, each set of ultrasonic transducers being installed opposite each other on both sides of the pipe along the pipe extension direction, the ultrasonic transducers being used to transmit and receive sound waves within the pipe. The control unit is connected to each group of ultrasonic flow meters and includes: a satellite signal receiving unit, a time measurement unit, and a counting unit; The satellite signal receiving unit is connected to the time measurement unit and is used to generate standard time frequency pulses; The time measurement unit includes a crystal oscillator and a calibration module. The crystal oscillator is used to generate crystal frequency pulses, and the calibration module is used to calibrate the time measured by the time measurement unit. The counting unit is connected to the time measurement unit and the satellite signal receiving unit, and is used to count the crystal oscillator frequency pulses and the standard time frequency pulses, respectively. The control unit is used to determine the sound velocity measurement deviation of the ultrasonic flow meter based on the ultrasonic transmission time, ultrasonic reception time, and pre-calculated theoretical sound velocity of the ultrasonic transducer in the pipeline; when the sound velocity measurement deviation exceeds the preset deviation range, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is determined based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time; the crystal oscillator frequency is corrected according to the deviation, and the time length between the ultrasonic transmission time and the ultrasonic reception time is remeasured using the corrected crystal oscillator frequency; the sound velocity is calculated based on the remeasured time length between the ultrasonic transmission time and the ultrasonic reception time.

2. The system according to claim 1, characterized in that, The control unit is further configured to: determine a calibration coefficient based on the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse; and use the calibration coefficient to correct the sound velocity of the ultrasonic flow meter.

3. An automatic calibration method for the sound velocity of a gas ultrasonic flow meter, characterized in that, The method applies the system according to any one of claims 1-2, and the method includes: The sound velocity measurement deviation of the ultrasonic flow meter is determined based on the length of the ultrasonic wave propagation path in the pipe, the time between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity. The time between the ultrasonic wave transmission time and the ultrasonic wave reception time is measured by the time measurement unit. When the sound speed measurement deviation exceeds the preset deviation range, the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is determined based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time period. The crystal oscillator frequency is corrected according to the deviation, and the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time is remeasured using the corrected crystal oscillator frequency. The speed of sound is calculated based on the time interval between the remeasured ultrasonic wave transmission time and the ultrasonic wave reception time.

4. The method according to claim 3, characterized in that, The deviation between the crystal oscillator frequency pulse and the standard time-frequency pulse is determined by: Determine the difference between the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time period; The deviation between the crystal oscillator frequency pulse and the standard time frequency pulse is obtained by taking the ratio of the difference to the standard time frequency pulse of the satellite signal receiving unit.

5. The method according to claim 4, characterized in that, Correcting the crystal oscillator frequency based on the aforementioned deviation includes: f t ′=-E t ×f t +f t ; Among them, f t ′ represents the crystal oscillator pulse frequency in the calibrated time measurement unit; f t E represents the frequency of the crystal oscillator pulse generated in the time measurement unit before calibration. t This indicates the deviation between the number of crystal oscillator frequency pulses and the standard time frequency pulses.

6. The method according to claim 5, characterized in that, When the ultrasonic flow meter includes multiple sets of ultrasonic transducers, the velocity of sound is calculated based on the time interval between the remeasured ultrasonic transmission time and the ultrasonic reception time, including: The weighted sound velocity measured by multiple sets of ultrasonic transducers is determined according to the following formula: Among them, c 测 c represents the corrected speed of sound. j Let a represent the velocity of sound measured by the j-th group of ultrasonic transducers before calibration. j The weight corresponding to the calculated sound velocity value of the j-th group of ultrasonic transducers is indicated, wherein the weight is related to the pipe cross-section path across the sound channel.

7. The method according to claim 6, characterized in that, Based on the length of the ultrasonic wave propagation path within the pipe, the time between ultrasonic wave transmission and reception, and the pre-calculated theoretical sound velocity, the sound velocity measurement deviation of the ultrasonic flow meter is determined, including: The theoretical speed of sound is determined based on the composition, temperature, and pressure of natural gas. The velocity of sound is determined based on the ultrasonic wave transmission time, ultrasonic wave reception time, and the distance between ultrasonic transducers. The measurement deviation is determined by the ratio of the difference between the measured sound speed and the theoretical sound speed to the measured sound speed.

8. An automatic calibration device for the sound velocity of a gas ultrasonic flow meter, characterized in that, The device includes: The sound velocity deviation determination unit is used to determine the sound velocity measurement deviation of the ultrasonic flow meter based on the length of the ultrasonic wave propagation path in the pipe, the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time, and the pre-calculated theoretical sound velocity. The time length between the ultrasonic wave transmission time and the ultrasonic wave reception time is measured by the time measurement unit. The frequency deviation determination unit is used to determine the deviation between the crystal oscillator frequency pulse and the standard time frequency pulse based on the number of crystal oscillator frequency pulses generated by the time measurement unit and the number of standard time frequency pulses of the satellite signal receiving unit within a preset time period when the sound speed measurement deviation exceeds the preset deviation range. The correction unit is used to correct the crystal oscillator frequency according to the deviation, and to remeasure the time length between the ultrasonic wave transmission time and the ultrasonic wave reception time using the corrected crystal oscillator frequency. The sound velocity calculation unit is used to calculate the sound velocity based on the time length between the remeasured ultrasonic wave transmission time and the ultrasonic wave reception time.

9. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 3 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the method according to any one of claims 3 to 7.

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