Flow integrating system based on gas ultrasonic flow meter

Abstract

The invention relates to the technical field of gas ultrasonic flow meters, in particular to a flow integrating system based on a gas ultrasonic flow meter. The system comprises a data acquisition unit which acquires and stores data based on an acquisition and storage module; the ultrasonic transduction unit converts sound energy into an ultrasonic signal through an ultrasonic transducer based on the data acquired by the data acquisition unit; the flow measuring unit is used for driving a transducer, amplifying the ultrasonic signal and carrying out filtering and operation processing on the basis of the ultrasonic signal converted by the ultrasonic transduction unit; the flow integrating unit collects instantaneous flow, temperature and pressure data according to the operation processing result of the flow measuring unit, calculates the optimal compression factor, calculates the working condition accumulated flow, the standard condition instantaneous flow and the standard condition accumulated flow, and displays the values through a liquid crystal display screen. Through signal amplification, filtering and automatic gain control, noise and interference are effectively removed, and the signal quality and the signal-to-noise ratio are improved.

Description

Technical Field

[0001] The invention relates to the technical field of gas ultrasonic flow meters, in particular to a flow totalizing system based on a gas ultrasonic flow meter. Background Art

[0002] The flow totalization system based on the gas ultrasonic flow meter is a precise measurement and control system that uses ultrasonic technology to non-invasively measure the gas flow through the pipeline, and converts the received ultrasonic data into accurate flow information through complex signal processing algorithms. The system can not only monitor and record key parameters such as instantaneous flow and cumulative flow of the gas in real time, but also analyze and process the data to provide standard volume flow after temperature and pressure compensation to ensure high accuracy and reliability of the measurement results. In addition, it is usually equipped with advanced microelectronics and embedded systems, supports multiple communication protocols, and can be seamlessly integrated into larger automation or energy management systems to achieve remote monitoring, fault diagnosis, and optimization control functions. It is widely used in gas transportation and trade settlement processes in natural gas, petroleum, chemical and other industries, and is of great significance to improving energy efficiency, ensuring safe operation and meeting strict environmental protection requirements.

[0003] In the existing flow integration system based on gas ultrasonic flow meter, the measurement accuracy of the system may be affected by fluid conditions. For example, when there are more bubbles, particulate matter or dirt in the pipeline, these factors will interfere with the propagation of ultrasonic signals, resulting in deviations in the measurement results. Temperature also has a significant impact on measurement accuracy, because the ultrasonic transducer and the coupling material between it and the pipeline have limited temperature resistance and are usually only applicable to fluid environments below 200°C; under high temperature conditions, the sound velocity change of the measured fluid lacks sufficient original data support, which further limits its application field. In order to ensure the measurement accuracy, the system has very strict requirements for the straight pipe section. Generally, an unobstructed straight pipe section of 20D in front and 5D in the back (D is the pipe diameter) is required, otherwise it will increase the discreteness and reduce the reliability of the measurement. The uncertainty of the installation position will also bring large errors to the flow measurement, especially when the field conditions are complex, it is difficult to ensure the best installation position. Dirt or moisture is easily accumulated at the probe, which will affect the accuracy of the measurement in the long run and even cause the instrument to fail to work properly. Therefore, a flow integration system based on gas ultrasonic flow meter is designed. Summary of the invention

[0004] The purpose of the present invention is to provide a flow integration system based on a gas ultrasonic flow meter to solve the problem proposed in the above background technology that in the existing flow integration system based on a gas ultrasonic flow meter, the measurement accuracy of the system may be affected by the fluid conditions. For example, when there are more bubbles, particulate matter or dirt in the pipeline, these factors will interfere with the propagation of the ultrasonic signal, resulting in deviations in the measurement results. Temperature also has a significant impact on measurement accuracy, because the ultrasonic transducer and the coupling material between it and the pipeline have limited temperature resistance and are usually only applicable to fluid environments below 200°C; and under high temperature conditions, the sound velocity change of the measured fluid lacks sufficient original data support, which further limits its application field. In order to ensure measurement accuracy, the system has very strict requirements for straight pipe sections, generally requiring an unobstructed straight pipe section of 20D in front and 5D in the back (D is the pipe diameter), otherwise it will increase the discreteness and reduce the reliability of the measurement. The uncertainty of the installation position will also bring large errors to the flow measurement, especially when the field conditions are complex, it is difficult to ensure the best installation position. Dirt or moisture is easily accumulated at the probe, which will affect the accuracy of the measurement in the long run and even cause the instrument to fail to work properly.

[0005] To achieve the above object, the present invention aims to provide a flow totalizing system based on a gas ultrasonic flow meter, comprising a data acquisition unit, which acquires and stores data based on an acquisition storage module;

[0006] An ultrasonic transducer unit, which converts acoustic energy into an ultrasonic signal through an ultrasonic transducer based on the data collected by the data collection unit;

[0007] A flow measurement unit, which drives a transducer, amplifies the ultrasonic signal, and performs filtering and calculation processing based on the ultrasonic signal converted by the ultrasonic transducer unit;

[0008] The flow integrating unit calculates the optimal compression factor according to the result of the flow measuring unit's operation and processing, through the collected instantaneous flow, temperature and pressure data, realizes the calculation of the working condition cumulative flow, standard condition instantaneous flow and standard condition cumulative flow, and displays these values on a liquid crystal display.

[0009] As a further improvement of the technical solution, the data acquisition unit includes an acquisition storage module, and the acquisition storage module includes a temperature and pressure sensor module and a database module;

[0010] Wherein, the temperature and pressure sensor module is used to collect temperature and pressure data related to gas flow;

[0011] The database module is used to store temperature and pressure data related to gas flow.

[0012] As a further improvement of this technical solution, the specific steps of converting acoustic energy into ultrasonic signals by the ultrasonic transducer are as follows:

[0013] S3.1. Install a pair of ultrasonic transducers at the designated positions on the meter body;

[0014] S3.2. Drive the transmitting transducer to generate ultrasonic signals through TTL level signals;

[0015] S3.3. After the receiving transducer captures the ultrasonic signals, convert them into electrical signals;

[0016] S3.4. Calculate the flow rate of the gas between the two transducers by measuring the time difference of the ultrasonic wave propagation between the two transducers.

[0017] As a further improvement of this technical solution, in step S3.4, the specific calculation process of calculating the flow rate of the gas between the two transducers by measuring the time difference of the ultrasonic wave propagation between the two transducers is as follows;

[0018] The time difference of the ultrasonic wave propagation between the two transducers is Δt h ;

[0019] Then the flow rate of the gas between the two transducers is:

[0020]

[0021] where, v h represents the flow rate; d h represents the distance between the two transducers.

[0022] As a further improvement of this technical solution, the specific steps involved in driving the transducer, amplifying the ultrasonic signals, and performing filtering and arithmetic processing based on the ultrasonic signals converted by the ultrasonic transducer unit are as follows:

[0023] S5.1. Periodically drive the ultrasonic transducer to generate and receive ultrasonic signals;

[0024] S5.2. Amplify, filter, and digitize the received ultrasonic signals to remove noise and interference;

[0025] S5.3. Calculate the forward and reverse time differences of the ultrasonic wave propagation in the pipeline to determine the gas flow rate in the pipeline;

[0026] S5.4. Calculate the gas flow rate in the pipeline according to the time difference and convert it into the instantaneous flow rate under working conditions;

[0027] S5.5. Transmit the instantaneous flow rate, acoustic time, acoustic velocity, signal-to-noise ratio, gain control value, and signal utilization rate data to the flow integration unit through the TTL serial communication port.

[0028] As a further improvement of this technical solution, in S5.2, the specific process of amplifying, filtering, and digitizing the received ultrasonic signal to remove noise and interference is as follows:

[0029] S5.21. The ultrasonic signal received by the ultrasonic transducer is usually a weak electrical signal, and pre-amplification is performed to improve the signal-to-noise ratio;

[0030] Among them, the expression of pre-amplification is:

[0031] V out = A·V in ;

[0032] Among them, V out represents the amplified output voltage; A represents the amplification factor; V in represents the input voltage;

[0033] S5.22. The high-frequency noise and unnecessary frequency components are removed through a low-pass filter to retain the ultrasonic signal frequency band;

[0034] Among them, the expression of the low-pass filter is:

[0035]

[0036] Among them, H(f) represents the frequency response; ω represents the angular frequency; C represents the angular frequency; R represents the resistance; j represents the imaginary unit;

[0037] S5.23. The amplification factor is dynamically adjusted according to the signal strength to ensure that the signal amplitude is within an appropriate range and avoid overload and distortion;

[0038] Among them, dynamically adjusting the amplification factor according to the signal strength is:

[0039]

[0040] Among them, G represents the gain; V ref represents the reference voltage; V avg represents the average signal voltage;

[0041] S5.24. The amplified analog signal is converted into a digital signal for subsequent digital processing;

[0042] Among them, converting the amplified analog signal into a digital signal is:

[0043]

[0044] Among them, D represents the digital output value; V analog represents the analog input voltage; n represents the ADC resolution;

[0045] S5.25. Further use an FIR filter to remove residual noise and interference to improve the signal quality.

[0046] As a further improvement of this technical solution, in S5.3, calculating the forward and reverse time differences of the ultrasonic wave propagating in the pipeline to determine the specific calculation process of the gas flow velocity in the pipeline is as follows:

[0047] S5.31. Drive the transmitting transducer to generate an ultrasonic signal through a TTL level signal and record the transmission time t0.

[0048] After the receiving transducer captures the ultrasonic signal, record the receiving times t1 and t2, corresponding to the downstream and upstream directions respectively.

[0049] S5.33. Calculate the time difference Δt between the downstream and upstream flows.

[0050] Among them, the calculation of the time difference Δt between the downstream and upstream flows is:

[0051] Δt = t2 - t1;

[0052] Among them, t1 represents the receiving time in the downstream direction; t2 represents the receiving time in the upstream direction.

[0053] S5.34. Perform temperature compensation on the time difference according to the real-time temperature data to eliminate the influence of temperature change on the sound speed.

[0054] Among them, the calculation process of performing temperature compensation on the time difference according to the real-time temperature data is:

[0055] c(T) = c0(1 + αT + βT 2 )

[0056] Among them, c(T) represents the sound speed at temperature T; c0 represents the sound speed at the reference temperature; α represents the linear temperature coefficient; β represents the quadratic temperature coefficient; T represents the current temperature.

[0057] S5.35. Perform pressure compensation on the time difference according to the real-time pressure data to ensure the accuracy of the measurement result.

[0058] Among them, the calculation process of performing pressure compensation on the time difference according to the real-time pressure data is:

[0059] c(P) = c(T)(1 + γP);

[0060] Among them, c(P) represents the sound speed at pressure P; γ represents the pressure coefficient; P represents the current pressure.

[0061] As a further improvement of this technical solution, in S5.4, the specific process of calculating the gas flow rate in the pipeline based on the time difference and converting it into the instantaneous flow rate under operating conditions is as follows:

[0062] S5.41. Calculate the gas flow velocity v in the pipeline according to the time difference Δt and the pipeline diameter D;

[0063] Among them, the expression for calculating the gas flow velocity is:

[0064]

[0065] Among them, L represents the sound channel length;

[0066] S5.42. Calculate the instantaneous flow rate Q under operating conditions according to the pipeline cross-sectional area S and the gas flow velocity v in the pipeline actual ;

[0067] Among them, the expression for calculating the instantaneous flow rate under operating conditions is:

[0068] Q actual = S·v;

[0069] S5.43. Calculate the compression factor Z of the gas according to the real-time temperature and pressure data;

[0070] Among them, the expression for calculating the compression factor of the gas is:

[0071] Z = f(P, T);

[0072] S5.44. Apply the compression factor Z to convert the instantaneous flow rate under operating conditions into the instantaneous flow rate under standard conditions Q std ;

[0073] Among them, the expression for calculating the instantaneous flow rate under standard conditions is:

[0074]

[0075] Among them, P std represents the standard pressure; T std represents the standard temperature;

[0076] S5.45. Accumulate the instantaneous flow rate under operating conditions to obtain the cumulative flow rate Q under operating conditions total,actual , accumulate the instantaneous flow rate under standard conditions to obtain the cumulative flow rate Q under standard conditions total,std ;

[0077] Among them, the cumulative flow rate under operating conditions is:

[0078] Q total,actual = ∫Q actual (t)dt;

[0079] The cumulative flow rate under standard conditions is:

[0080] Q total,std = ∫Q std (t)dt;

[0081] Wherein, ∫ represents the integral symbol; t represents time; dt represents the time interval.

[0082] As a further improvement of this technical solution, the specific steps involved in collecting instantaneous flow rate, temperature and pressure data, calculating the optimal compression factor, realizing the calculation of cumulative flow rate under working conditions, instantaneous flow rate under standard conditions and cumulative flow rate under standard conditions, and displaying these values on the liquid crystal display are as follows:

[0083] S9.1. Receive the instantaneous flow rate data from the flow measurement unit, and obtain the real-time temperature and pressure data through the built-in temperature and pressure sensors;

[0084] S9.2. Calculate the optimal compression factor according to the AGA8-92DC standard method;

[0085] S9.3. Apply the compression factor to correct the instantaneous flow rate under standard conditions, accumulate the instantaneous flow rate under standard conditions, and record the cumulative flow rate under standard conditions;

[0086] S9.4. Display the converted values of measurement and calculation on the liquid crystal display;

[0087] S9.5. Transmit the data to the upper computer through the RS485 interface for remote monitoring, and save the measurement data for the user to download.

[0088] As a further improvement of this technical solution, in the above S9.2, the specific calculation process of calculating the optimal compression factor according to the AGA8-92DC standard method is:

[0089] Take the real-time temperature T(t) and pressure P(t) as input parameters;

[0090] Then the calculation expression for selecting the AGA8-92DC standard method is;

[0091]

[0092] Wherein, Z′ represents the optimal compression factor; P′ represents the absolute pressure; T′ represents the absolute temperature; V represents the volume; m represents the number of moles; Q represents the ideal gas constant.

[0093] Compared with the prior art, the beneficial effects of the present invention:

[0094] 1. In the flow integration system based on a gas ultrasonic flowmeter, the acquisition and storage module is used to obtain and efficiently store the flow rate, temperature, and pressure data from the sensor in real time, ensuring the accuracy and availability of the data and providing a solid foundation for flow monitoring and analysis. The ultrasonic transducer can quickly and accurately convert the electrical signal into an ultrasonic signal and receive the returned ultrasonic signal, ensuring the real-time and accuracy of the measurement. By adopting the direct and reflection type sound channel layout, multi-point sampling is achieved, effectively solving the problem of uneven flow field in the pipeline and improving the reliability and stability of the measurement.

[0095] 2. In the flow integration system based on a gas ultrasonic flowmeter, through signal amplification, filtering, and automatic gain control, noise and interference are effectively removed, improving the signal quality and signal-to-noise ratio and ensuring the accuracy of the measurement. A high-precision analog-to-digital converter, usually with a resolution of 12 bits or higher, is adopted to ensure the accuracy and reliability of the data. According to the AGA8-92DC standard method, the optimal compression factor is calculated to ensure the accuracy of the standard condition flow rate. The compression factor is applied to correct the standard condition instantaneous flow rate, and the working condition and standard condition cumulative flow rates are accumulated to ensure the high precision and reliability of the flow measurement. Brief Description of the Drawings

[0096] Figure 1 is the overall flow block diagram of the present invention;

[0097] The meanings of the reference numerals in the figure are as follows:

[0098] 1. Data acquisition unit; 2. Ultrasonic transducer unit; 3. Flow measurement unit; 4. Flow integration unit. Detailed Embodiment

[0099] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0100] Embodiment

[0101] Please refer to Figure 1 As shown, a flow integration system based on a gas ultrasonic flowmeter is provided, including a data acquisition unit 1. The data acquisition unit 1 acquires and stores data based on the acquisition and storage module;

[0102] In this example, the data acquisition unit 1 includes an acquisition and storage module, and the acquisition and storage module includes a temperature and pressure sensor module and a database module;

[0103] Among them, the temperature and pressure sensor module is used to collect temperature and pressure data related to gas flow;

[0104] Specifically, the temperature and pressure sensor module is an integrated measuring device used to collect and provide real-time temperature and pressure data during gas flow. These data are crucial for compensating and calculating the actual flow rate, ensuring measurement accuracy, and monitoring the safety and stability of operating conditions. Through accurate temperature and pressure measurements, this module helps the flow integration system achieve more accurate gas flow monitoring and management.

[0105] The database module is used to store temperature and pressure data related to gas flow.

[0106] Specifically, the database module is a system component for storing, managing, and processing data. It is responsible for receiving data from various sensors (such as the temperature and pressure sensor module) and ultrasonic flow meters in the flow integration system, performing efficient data storage, retrieval, and analysis to ensure data integrity and availability. At the same time, it supports historical data query, report generation, and data exchange with external systems, providing solid data support for flow monitoring and management.

[0107] This flow integration system based on an ultrasonic gas flow meter further includes an ultrasonic transducer unit 2. The ultrasonic transducer unit 2 converts acoustic energy into ultrasonic signals through ultrasonic transducers based on the data collected by the data acquisition unit 1;

[0108] Specifically, an ultrasonic transducer is a component that converts acoustic energy into an electrical signal or vice versa. A pair of ultrasonic transducers is installed on the transducer mounting seat of the meter body. The converter generates an electrical pulse signal to drive the transmitting transducer to generate ultrasonic waves, and the paired transducer receives the ultrasonic wave signal and converts it into an electrical signal.

[0109] In this example, the specific steps for converting acoustic energy into ultrasonic signals through ultrasonic transducers are as follows:

[0110] S3.1: Install a pair of ultrasonic transducers at the designated position on the meter body;

[0111] S3.2: Drive the transmitting transducer to generate ultrasonic signals through a TTL level signal;

[0112] Specifically, TTL level signal driving means using an electrical signal with the Transistor-Transistor Logic (TTL) level standard to control or activate the operation of an electronic device or circuit. TTL is a digital logic circuit technology that specifies voltage levels to represent binary "0" and "1". In standard TTL logic, "0" corresponds to a voltage between 0 and 0.8 volts, while "1" corresponds to a voltage between 2.0 and 5.0 volts. In the application of ultrasonic flowmeters, TTL level signals are used to generate precise pulse sequences, which drive the transmitting transducer to generate ultrasonic signals. By controlling the frequency, amplitude, and duration of the TTL signal, the emission characteristics of ultrasonic waves can be optimized to ensure the accuracy and reliability of measurement. In addition, TTL level signals also have good compatibility and stability, facilitating interfacing with other digital circuits or microcontrollers to achieve system integration and automated control.

[0113] S3.3 After the receiving transducer captures the ultrasonic signal, it converts it into an electrical signal;

[0114] S3.4 By measuring the time difference of the ultrasonic wave propagating between the two transducers, the flow rate of the gas between the two transducers is calculated.

[0115] In this example, the specific calculation process for calculating the flow rate of the gas between the two transducers by measuring the time difference of the ultrasonic wave propagating between the two transducers is as follows;

[0116] The time difference of the ultrasonic wave propagating between the two transducers is Δt h ;

[0117] Then the flow rate of the gas between the two transducers is:

[0118]

[0119] Among them, v h represents the flow rate; d h represents the distance between the two transducers.

[0120] Specifically, after the ultrasonic transducer is installed at the designated position on the meter body, the system uses TTL level signals to drive the transmitting transducer to generate ultrasonic signals. The receiving transducer captures these signals and converts them into electrical signals. By accurately measuring the time difference of the ultrasonic wave propagating in the downstream and upstream directions between the two transducers, the system calculates the gas flow velocity between the two transducers; this flow velocity measurement is one of the core functions of the flow integration system, which provides real-time and accurate gas flow velocity data, and is crucial for subsequent flow calculation. Specifically, this flow velocity data is used to calculate the instantaneous flow rate, and combined with the data provided by the temperature and pressure sensors, the actual flow rate under the working conditions is adjusted to the standard conditions by calculating the compression factor, so as to achieve the accurate calculation of the cumulative flow rate under the working conditions, the instantaneous flow rate under the standard conditions, and the cumulative flow rate under the standard conditions. This process ensures the high precision and reliability of the flow measurement, supports the safe and efficient operation of the gas transmission pipeline, and provides reliable data support for energy management and trade settlement.

[0121] The flow integration system based on the gas ultrasonic flowmeter further includes a flow measurement unit 3. The flow measurement unit 3 drives the transducer, amplifies the ultrasonic signal, and performs filtering and arithmetic processing based on the ultrasonic signal converted by the ultrasonic transducer unit 2;

[0122] In this example, the specific steps involved in driving the transducer, amplifying the ultrasonic signal, and performing filtering and arithmetic processing based on the ultrasonic signal converted by the ultrasonic transducer unit 2 are as follows:

[0123] S5.1. Periodically drive the ultrasonic transducer to generate and receive ultrasonic signals;

[0124] S5.2. Amplify, filter, and digitize the received ultrasonic signal to remove noise and interference;

[0125] In this example, the specific process involved in amplifying, filtering, and digitizing the received ultrasonic signal to remove noise and interference is as follows:

[0126] S5.21. The ultrasonic signal received by the ultrasonic transducer is usually a weak electrical signal, and pre-amplification is performed to improve the signal-to-noise ratio;

[0127] Among them, the expression of pre-amplification is:

[0128] V out =A@V in ;

[0129] Among them, V out represents the amplified output voltage; A represents the amplification factor; V in represents the input voltage;

[0130] S5.22. Remove high-frequency noise and unwanted frequency components through a low-pass filter to retain the ultrasonic signal frequency band;

[0131] Specifically, a low-pass filter is an electronic circuit or mathematical tool that allows signals below a specific cut-off frequency to pass through while attenuating signals above that frequency, thus effectively removing high-frequency noise and interference. In signal processing, it helps smooth the signal, reduce unnecessary high-frequency components, and ensure the accuracy of subsequent analysis or measurement. Low-pass filters are widely used in audio processing, communication systems, control systems, and sensor data processing to improve signal quality and system performance. For example, in an ultrasonic flowmeter, a low-pass filter can be used to eliminate high-frequency noise in the received signal, ensuring the accuracy and reliability of flow rate measurement.

[0132] Among them, the expression of the low-pass filter is:

[0133]

[0134] Among them, H(f) represents the frequency response; ω represents the angular frequency; C represents the angular frequency; R represents the resistance; j represents the imaginary unit;

[0135] S5.23. Dynamically adjust the amplification factor according to the signal strength to ensure that the signal amplitude is within an appropriate range and avoid overload and distortion;

[0136] Among them, dynamically adjusting the amplification factor according to the signal strength is:

[0137]

[0138] Among them, G represents the gain; V ref represents the reference voltage; V avg represents the average signal voltage;

[0139] S5.24. Convert the amplified analog signal into a digital signal for subsequent digital processing;

[0140] Among them, converting the amplified analog signal into a digital signal is:

[0141]

[0142] Among them, D represents the digital output value; V analog represents the analog input voltage; n represents the ADC resolution;

[0143] S5.25. Further use a FIR filter to remove residual noise and interference to improve signal quality.

[0144] Specifically, a FIR filter (Finite Impulse Response Filter) is a digital signal processing tool characterized by a finite-length impulse response, which means it only responds to the input signal within a finite time. The FIR filter achieves the filtering effect by weighted summation of a series of delayed input samples and can be precisely designed to meet specific frequency response requirements, such as low-pass, high-pass, band-pass, or band-stop characteristics. Due to its linear phase characteristics and stability, the FIR filter is widely used in fields such as audio processing, communication systems, image processing, and control systems, especially suitable for application scenarios that require maintaining the phase relationship of signals. In addition, the FIR filter is easy to implement and its performance can be optimized by adjusting the filter coefficients, so it is very popular in digital signal processing.

[0145] High precision and high reliability are required throughout the entire process from the generation, reception, and processing of ultrasonic signals to the final flow velocity calculation. Through precise time difference measurement and compensation for environmental conditions (temperature and pressure), the system can accurately calculate the gas flow velocity in the pipeline and convert it into the instantaneous flow rate under operating conditions. These data are then used to calculate the cumulative flow rate under operating conditions, the instantaneous flow rate under standard conditions, and the cumulative flow rate under standard conditions, providing reliable data support for the safe operation, energy management, and trade settlement of gas transmission pipelines. In addition, through the TTL serial communication port, these key parameters are transmitted to the flow integrator unit, realizing the integrated and automated management of the system.

[0146] S5.3. Calculate the forward and reverse time differences of ultrasonic wave propagation in the pipeline to determine the gas flow velocity in the pipeline;

[0147] In this example, the specific calculation process involved in calculating the forward and reverse time differences of ultrasonic wave propagation in the pipeline to determine the gas flow velocity in the pipeline is as follows:

[0148] S5.31. Drive the transmitting transducer to generate an ultrasonic signal through a TTL level signal and record the transmission time t0;

[0149] S5.32. After the receiving transducer captures the ultrasonic signal, record the receiving times t1 and t2, corresponding to the forward and reverse flow directions respectively;

[0150] S5.33. Calculate the time difference Δt between the forward and reverse flows;

[0151] Among them, the calculation of the time difference Δt between the forward and reverse flows is:

[0152] Δt = t2 - t1;

[0153] Among them, t1 represents the receiving time in the forward flow direction; t2 represents the receiving time in the reverse flow direction;

[0154] S5.34. Perform temperature compensation on the time difference according to the real-time temperature data to eliminate the influence of temperature changes on the sound speed;

[0155] Among them, the calculation process of performing temperature compensation on the time difference according to the real-time temperature data is as follows:

[0156] c(T) = c0(1 + αT + βT 2 );

[0157] Among them, c(T) represents the sound speed at temperature T; c0 represents the sound speed at the reference temperature; α represents the linear temperature coefficient; β represents the quadratic temperature coefficient; T represents the current temperature;

[0158] S5.35. Perform pressure compensation on the time difference according to the real-time pressure data to ensure the accuracy of the measurement results;

[0159] Among them, the calculation process of performing pressure compensation on the time difference according to the real-time pressure data is as follows:

[0160] c(P) = c(T)(1 + γP);

[0161] Among them, c(P) represents the sound speed at pressure P; γ represents the pressure coefficient; P represents the current pressure.

[0162] Specifically, the entire process from ultrasonic signal reception, amplification, filtering to digitization is efficient and accurate. By pre-amplification, the signal-to-noise ratio is improved; low-pass filtering removes high-frequency noise; dynamic gain adjustment maintains signal stability; analog-to-digital conversion digitizes the signal; and FIR filtering further purifies the signal. The system can obtain high-precision and reliable ultrasonic propagation time data. These data are the basis for calculating the gas flow velocity and instantaneous flow rate, and ultimately used to accurately calculate the working condition cumulative flow rate, standard condition instantaneous flow rate, and standard condition cumulative flow rate. In addition, high-quality signal processing also improves the anti-interference ability and long-term operation stability of the system, ensures the safe and efficient operation of the gas transmission pipeline, and provides reliable data support for energy management and trade handover.

[0163] S5.4. Calculate the gas flow velocity in the pipeline according to the time difference and convert it into the working condition instantaneous flow rate;

[0164] In this example, the specific process involved in calculating the gas flow velocity in the pipeline according to the time difference and converting it into the working condition instantaneous flow rate is as follows:

[0165] S5.41. Calculate the gas flow velocity v in the pipeline according to the time difference Δt and the pipeline diameter D;

[0166] Among them, the expression for calculating the gas flow velocity is:

[0167]

[0168] Among them, L represents the length of the sound channel;

[0169] S5.42. Calculate the instantaneous flow rate Q under the operating conditions according to the cross-sectional area S of the pipeline and the gas flow velocity v in the pipeline actual ;

[0170] Among them, the expression for calculating the instantaneous flow rate under the operating conditions is:

[0171] Q actual = S·v;

[0172] S5.43. Calculate the compression factor Z of the gas according to the real-time temperature and pressure data;

[0173] Among them, the expression for calculating the compression factor of the gas is:

[0174] Z = f(P, T);

[0175] S5.44. Apply the compression factor Z to convert the instantaneous flow rate under the operating conditions into the instantaneous flow rate Q under the standard conditions std ;

[0176] Among them, the expression for calculating the instantaneous flow rate under the standard conditions is:

[0177]

[0178] Among them, P std represents the standard pressure; T std represents the standard temperature;

[0179] S5.45. Accumulate the instantaneous flow rate under the operating conditions to obtain the cumulative flow rate Q under the operating conditions total,actual , accumulate the instantaneous flow rate under the standard conditions to obtain the cumulative flow rate Q under the standard conditions total,std ;

[0180] Among them, the cumulative flow rate under the operating conditions is:

[0181] Q total,actual = ∫Q actual (t)dt;

[0182] The cumulative flow rate under the standard conditions is:

[0183] Q total,std = ∫Q std (t)dt;

[0184] Among them, ∫ represents the integral symbol; t represents time; dt represents the time interval.

[0185] Specifically, first, the system uses the time difference of ultrasonic wave propagation in the pipeline and the pipeline diameter to calculate the gas flow rate. Then, the operating condition instantaneous flow rate is obtained by the pipeline cross-sectional area and the calculated flow rate. Then, the system calculates the compression factor of the gas based on the real-time temperature and pressure data to take into account the compressibility of the gas under different conditions. After that, the compression factor is applied to convert the operating condition instantaneous flow rate into the instantaneous flow rate under standard conditions to ensure that the measurement results meet the standard conditions. Finally, the system accumulates the operating condition instantaneous flow rate to obtain the operating condition cumulative flow rate, and accumulates the standard condition instantaneous flow rate to obtain the standard condition cumulative flow rate. This series of steps ensures the accuracy and reliability from flow rate measurement to flow calculation, and provides accurate data support for the safe operation, energy management and trade transfer of gas pipelines.

[0186] S5.5. The instantaneous flow rate, sound time, sound speed, signal-to-noise ratio, gain control value and signal utilization rate data are transmitted to the flow totalizing unit 4 through the TTL serial communication port.

[0187] Specifically, the TTL serial communication port is a digital communication interface based on the transistor-transistor logic (TTL) level standard, which is used for serial data transmission between electronic devices. It sends and receives data bit by bit in a bit sequence through one or several lines, and usually uses logic levels (such as 0V for logic "0", 3.3V or 5V for logic "1") to represent binary information. TTL serial communication ports are often used for short-distance, low-rate data exchange between microcontrollers, sensors and other low-voltage digital devices. Because of its simplicity, low cost and easy implementation, it is widely used in embedded systems and measuring instruments. For example, in an ultrasonic flow meter, the TTL serial communication port can be used to transmit key parameters such as instantaneous flow, sound time, and sound velocity to the flow totalizer module or other external devices.

[0188] The system periodically drives the ultrasonic transducer to generate and receive ultrasonic signals to ensure continuous acquisition of data on the gas flow in the pipeline. The received ultrasonic signals are amplified, filtered and digitized to remove noise and interference to ensure the accuracy and reliability of the data. Subsequently, the system determines the gas flow rate in the pipeline by calculating the time difference between the ultrasonic wave propagating downstream and upstream in the pipeline. The gas flow rate calculated based on the time difference is further converted into the operating instantaneous flow rate, which is a step that is crucial for accurately measuring the gas flow rate. Finally, the system transmits key data such as instantaneous flow rate, sound time, sound speed, signal-to-noise ratio, gain control value and signal utilization rate to the flow integrator through the TTL serial communication port for subsequent flow accumulation, temperature and pressure compensation, and standard flow calculation, and finally provides users with intuitive flow information through the LCD display.

[0189] The flow integration system based on the gas ultrasonic flow meter also includes a flow integration unit 4. The flow integration unit 4 collects instantaneous flow, temperature and pressure data according to the results of the calculation and processing of the flow measurement unit 3, calculates the optimal compression factor, realizes the calculation of the operating condition cumulative flow, the standard condition instantaneous flow and the standard condition cumulative flow, and displays these values on a liquid crystal display.

[0190] In this example, the optimal compression factor is calculated through the collected instantaneous flow, temperature and pressure data, the calculation of the operating condition cumulative flow, the standard condition instantaneous flow and the standard condition cumulative flow is realized, and the specific steps involved in displaying these values on the LCD screen are as follows:

[0191] S9.1, receiving instantaneous flow data from the flow measurement unit (3), and obtaining real-time temperature and pressure data through the built-in temperature and pressure sensors;

[0192] S9.2. Calculate the optimal compression factor according to the AGA8-92DC standard method;

[0193] Specifically, the AGA8-92DC standard method is an algorithm developed by the American Gas Association (AGA) for calculating the compression factor of natural gas and other hydrocarbon gases. This method is based on polynomial expansion and can accurately consider the effects of temperature, pressure and gas composition on the compression factor, thereby providing more accurate gas volume and energy measurement. AGA8-92DC is widely used in the natural gas industry, especially in flow measurement and custody transfer, ensuring the consistency and reliability of gas measurement under different conditions. This method is essential to ensure fair trade, optimize pipeline operations and improve energy management efficiency.

[0194] In this example, the specific calculation process of calculating the optimal compression factor according to the AGA8-92DC standard method is:

[0195] The real-time temperature T(t) and pressure P(t) are used as input parameters;

[0196] Then choose AGA8-92DC standard method to calculate the expression:

[0197]

[0198] Among them, Z′ represents the optimal compression factor; P′ represents the absolute pressure; T′ represents the absolute temperature; V represents the volume; m represents the number of moles; and Q represents the ideal gas constant.

[0199] Specifically, the system uses real-time temperature and pressure as input parameters, and calculates the optimal compression factor through the AGA8-92DC standard method. This compression factor is used to adjust the instantaneous flow rate under operating conditions and convert it into the instantaneous flow rate under standard conditions, ensuring the accuracy and consistency of gas metering, thereby supporting the safe operation, energy management, and trade settlement of gas pipelines.

[0200] S9.3. Apply the compression factor to correct the instantaneous flow rate under standard conditions, accumulate the instantaneous flow rate under standard conditions, and record the cumulative flow rate under standard conditions;

[0201] S9.4. Display the converted measured and calculated values on the liquid crystal display screen;

[0202] S9.5. Transmit the data to the host computer through the RS485 interface for remote monitoring, and save the measurement data for users to download.

[0203] Specifically, the RS485 interface is a serial communication interface standard that supports multi-point communication and can reliably transmit data in long-distance and noisy electrical environments. It uses a differential signal transmission method and uses a pair of twisted pairs to send and receive data, thus effectively resisting electromagnetic interference and providing better signal integrity. The RS485 interface can connect up to 32 devices (expandable to more through repeaters), is suitable for fields such as industrial automation, building control, and intelligent meters, and is commonly used for data exchange and remote monitoring between devices. Its half-duplex or full-duplex working mode enables multiple devices to communicate on the same network without complex wiring.

[0204] The system first receives the instantaneous flow rate data from the flow measurement unit and obtains the real-time temperature and pressure data through the built-in temperature and pressure sensors. Then, it calculates the optimal compression factor according to the AGA8-92DC standard method to accurately reflect the compressibility of the gas under current conditions. Next, it applies this compression factor to correct the instantaneous flow rate under standard conditions and accumulates these corrected flow rate values, recording the cumulative flow rate under standard conditions. The corrected values are intuitively displayed on the liquid crystal display screen for easy on-site viewing. Finally, the system transmits all the measured and calculated data to the host computer through the RS485 interface to achieve remote monitoring, and saves the data for users to download and further analyze.

[0205] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A flow integration system based on a gas ultrasonic flowmeter, characterized in that: Including: A data acquisition unit (1), which acquires and stores data based on an acquisition and storage module. An ultrasonic transducer unit (2), which converts acoustic energy into ultrasonic signals through ultrasonic transducers based on the data acquired by the data acquisition unit (1). A flow measurement unit (3), which drives transducers, amplifies ultrasonic signals, and performs filtering and arithmetic processing based on the ultrasonic signals converted by the ultrasonic transducer unit (2). A flow integration unit (4), which calculates the optimal compression factor based on the results of the arithmetic processing of the flow measurement unit (3), and the acquired instantaneous flow rate, temperature, and pressure data, realizes the calculation of the working condition cumulative flow rate, standard condition instantaneous flow rate, and standard condition cumulative flow rate, and displays these values through a liquid crystal display screen.

2. The flow integration system based on a gas ultrasonic flowmeter according to claim 1, wherein: The data acquisition unit (1) includes an acquisition and storage module, and the acquisition and storage module includes a temperature and pressure sensor module and a database module. Among them, the temperature and pressure sensor module is used to acquire temperature and pressure data related to gas flow. The database module is used to store temperature and pressure data related to gas flow.

3. The flow integration system based on a gas ultrasonic flowmeter according to claim 1, wherein: The specific steps for converting acoustic energy into ultrasonic signals through ultrasonic transducers are as follows: S3.1: Install paired ultrasonic transducers at designated positions on the meter body. S3.2: Drive the transmitting transducer to generate ultrasonic signals through TTL level signals. S3.3: After the receiving transducer captures the ultrasonic signals, convert them into electrical signals. S3.4: Calculate the gas flow velocity between the two transducers by measuring the time difference of ultrasonic wave propagation between the two transducers.

4. The flow integration system based on a gas ultrasonic flowmeter according to claim 3, wherein: In the above S3.4, the specific calculation process for calculating the gas flow velocity between the two transducers by measuring the time difference of ultrasonic wave propagation between the two transducers is as follows; The time difference in the propagation between the two transducers is Δt h ; Then the gas flow velocity between the two transducers is: where, v h represents the flow velocity; d h represents the distance between the two transducers.

5. The flow integration system based on a gas ultrasonic flowmeter according to claim 1, wherein: The specific steps involved in driving transducers, amplifying ultrasonic signals, and performing filtering and arithmetic processing based on the ultrasonic signals converted by the ultrasonic transducer unit (2) are as follows: S5.1: Periodically drive ultrasonic transducers to generate and receive ultrasonic signals. S5.2: Amplify, filter, and digitize the received ultrasonic signals to remove noise and interference. S5.3: Calculate the forward and reverse time differences of ultrasonic wave propagation in the pipeline to determine the gas flow velocity in the pipeline. S5.4: Calculate the gas flow velocity in the pipeline based on the time difference and convert it into the working condition instantaneous flow rate. S5.5: Transmit the instantaneous flow rate, acoustic time, acoustic velocity, signal-to-noise ratio, gain control value, and signal utilization rate data to the flow integration unit (4) through the TTL serial communication port.

6. The flow integration system based on a gas ultrasonic flowmeter according to claim 5, characterized in that: In the above S5.2, the specific process involved in amplifying, filtering, and digitizing the received ultrasonic signals to remove noise and interference is as follows: S5.21: The ultrasonic signals received by the ultrasonic transducers are usually weak electrical signals, and pre-amplification is performed to improve the signal-to-noise ratio. Among them, the expression of pre-amplification is: V out = A·V in ; Among them, V out represents the amplified output voltage; A represents the amplification factor; V in represents the input voltage; S5.22: Remove high-frequency noise and unwanted frequency components through a low-pass filter to retain the ultrasonic signal frequency band. Among them, the expression of the low-pass filter is: Among them, H(f) represents the frequency response; ω represents the angular frequency; C represents the angular frequency; R represents the resistance; j represents the imaginary unit; S5.

23. Dynamically adjust the amplification factor according to the signal strength to ensure that the signal amplitude is within an appropriate range and avoid overload and distortion; Among them, dynamically adjusting the amplification factor according to the signal strength is: where G represents the gain; V ref represents the reference voltage; V avg represents the average signal voltage; S5.

24. Convert the amplified analog signal into a digital signal for subsequent digital processing; Among them, converting the amplified analog signal into a digital signal is: where D represents the digital output value; V analog represents the analog input voltage; n represents the ADC resolution; S5.

25. Further use an FIR filter to remove residual noise and interference to improve the signal quality.

7. The flow integration system based on a gas ultrasonic flowmeter according to claim 6, characterized in that: In the above-mentioned S5.3, the specific calculation process for calculating the forward and reverse time differences of ultrasonic wave propagation in the pipeline to determine the gas flow velocity in the pipeline is: S5.

31. Drive the transmitting transducer to generate an ultrasonic signal through a TTL level signal and record the transmission time t0; S5.

32. After the receiving transducer captures the ultrasonic signal, record the receiving times t1 and t2, corresponding to the forward flow and reverse flow directions respectively; S5.

33. Calculate the time difference Δt between the forward flow and the reverse flow; Among them, calculating the time difference Δt between the forward flow and the reverse flow is: Δt = t2 - t1; Among them, t1 represents the receiving time in the forward flow direction; t2 represents the receiving time in the reverse flow direction; S5.

34. Perform temperature compensation on the time difference according to the real-time temperature data to eliminate the influence of temperature change on the sound speed; Among them, the calculation process for performing temperature compensation on the time difference according to the real-time temperature data is: c(T) = c0(1 + αT + βT 2 ); Among them, c(T) represents the sound speed at temperature T; c0 represents the sound speed at the reference temperature; α represents the linear temperature coefficient; β represents the quadratic temperature coefficient; T represents the current temperature; S5.

35. Perform pressure compensation on the time difference according to the real-time pressure data to ensure the accuracy of the measurement result; Among them, the calculation process for performing pressure compensation on the time difference according to the real-time pressure data is: c(P) = c(T)(1 + γP); Among them, c(P) represents the sound speed at pressure P; γ represents the pressure coefficient; P represents the current pressure.

8. The flow integration system based on a gas ultrasonic flowmeter according to claim 7, characterized in that: In the above-mentioned S5.4, the specific process for calculating the gas flow velocity in the pipeline according to the time difference and converting it into the instantaneous flow rate under operating conditions is: S5.

41. Calculate the gas flow velocity v in the pipeline according to the time difference Δt and the pipeline diameter D; Among them, the expression for calculating the gas flow velocity is: Among them, L represents the sound path length; S5.

42. Calculate the instantaneous flow rate Q under the operating conditions according to the cross-sectional area S of the pipeline and the gas flow velocity v in the pipeline actual ; Among them, the expression for calculating the instantaneous flow rate under operating conditions is: Q actual = S·v; S5.

43. Calculate the compression factor Z of the gas according to the real-time temperature and pressure data; Among them, the expression for calculating the compression factor of the gas is: Z = f(P, T); S5.

44. Convert the instantaneous flow rate under the operating conditions to the instantaneous flow rate Q under standard conditions using the compressibility factor Z std ; Among them, the expression for calculating the instantaneous flow rate under standard conditions is: where P std represents the standard pressure; T std represents the standard temperature; S5.

45. Cumulatively process the instantaneous flow rate under the working condition to obtain the cumulative flow rate Q under the working condition total,actual , cumulatively process the instantaneous flow rate under the standard condition to obtain the cumulative flow rate Q under the standard condition total,std ; Among them, the cumulative flow rate under operating conditions is: Q total,actual = ∫Q actual (t) dt; The cumulative flow rate under standard conditions is: Q total,std = ∫Q std (t) dt; Among them, ∫ represents the integral symbol; t represents time; dt represents the time interval.

9. The flow integration system based on a gas ultrasonic flowmeter according to claim 1, wherein: The specific steps for collecting the instantaneous flow rate, temperature, and pressure data, calculating the optimal compression factor, realizing the calculation of the cumulative flow rate under operating conditions, the instantaneous flow rate under standard conditions, and the cumulative flow rate under standard conditions, and displaying these values through a liquid crystal display screen are: S9.

1. Receive the instantaneous flow rate data from the flow measurement unit (3), and obtain the real-time temperature and pressure data through the built-in temperature and pressure sensors; S9.

2. Calculate the optimal compressibility factor according to the AGA8-92DC standard method; S9.

3. Apply the compressibility factor to correct the instantaneous flow rate under standard conditions, accumulate the instantaneous flow rate under standard conditions, and record the cumulative flow rate under standard conditions; S9.

4. Display the converted values of measurement and calculation on the liquid crystal display screen; S9.

5. Transmit the data to the host computer through the RS485 interface for remote monitoring, and save the measurement data for users to download.

10. The flow integration system based on a gas ultrasonic flowmeter according to claim 9, characterized in that: In the above S9.2, the specific calculation process for calculating the optimal compressibility factor according to the AGA8-92DC standard method is as follows: Take the real-time temperature T(t) and pressure P(t) as input parameters; Then select the AGA8-92DC standard method for the calculation expression as; Among them, Z′ represents the optimal compressibility factor; P′ represents the absolute pressure; T′ represents the absolute temperature; V represents the volume; m represents the number of moles; Q represents the ideal gas constant.

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