A flow metering method for ultrasonic detection

Abstract

The application provides a flow metering statistical method for ultrasonic detection, a first transmission time is determined by a first ultrasonic detection group, a second transmission time is determined by a second ultrasonic detection group, and a detected flow value is determined by an ultrasonic flow detection device; a difference between the first transmission time and the second transmission time is a transmission change duration, a size relationship between the transmission change duration and first and second preset durations is judged, the first preset duration is smaller than the second preset duration, and the first and second preset durations are preset values; if the transmission change duration is smaller than or equal to the first preset duration, the detected flow value is taken as a flow output value; if the transmission change duration is greater than the first preset duration, a plurality of detected flow values are acquired in a same sampling period with different sampling frequencies, an average value of the plurality of detected flow values is taken as the flow output value, and the ultrasonic flow detection statistical precision is improved according to different liquid flow states.

Description

Technical Field

[0001] This invention relates to the field of flow detection technology for ultrasonic flow meters, and more particularly to a flow measurement and statistical method for ultrasonic detection. Background Technology

[0002] An ultrasonic flowmeter is an instrument or device used to measure the flow rate of liquids. It utilizes ultrasonic technology to achieve non-contact, high-precision flow measurement. This type of flowmeter is suitable for various types of liquids, including water, wastewater, chemicals, and petroleum. The main working principle of an ultrasonic flowmeter includes:

[0003] Sensor Location: Ultrasonic flow meters typically consist of two sensors, one as a transmitter and the other as a receiver. These two sensors are usually installed at different locations in the pipe, one along the direction of fluid flow.

[0004] Ultrasonic emission: The transmitter generates ultrasonic pulses and sends them into the fluid. These ultrasonic pulses propagate at a specific frequency. Ultrasonic reception: The receiver receives the ultrasonic pulses propagating through the fluid. The velocity and flow rate of the fluid affect the propagation speed of the ultrasonic waves.

[0005] Time difference measurement: By measuring the time difference between the transmitted and received ultrasonic pulses, the flow meter can calculate the velocity of the fluid. This time difference is often referred to as the "Doppler shift".

[0006] Flow calculation: Based on the Doppler frequency shift and the size and shape of the pipe, the flow meter can calculate the actual flow rate.

[0007] Ultrasonic flow meters typically offer high accuracy and are suitable for precise flow measurement, especially in high-flow-rate and low-velocity applications. The performance of an ultrasonic flow meter is influenced by factors such as the characteristics of the fluid within the pipe, the pipe material, and the sensor's installation location. Therefore, these factors must be considered when selecting and installing an ultrasonic flow meter to obtain accurate measurement results.

[0008] Ultrasonic flow meters typically offer high accuracy when measuring fluid flow rate, but this accuracy can be affected by a variety of factors. Here are some of the main reasons that influence the measurement accuracy of ultrasonic flow meters:

[0009] Fluid properties: Different types of fluids (such as water, oil, chemicals, etc.) have different effects on the propagation speed of ultrasound. The temperature, density, and viscosity of a fluid affect the propagation of ultrasound, therefore corrections are needed to account for these factors.

[0010] Flow rate range: The measurement accuracy of ultrasonic flow meters is generally optimal within a certain flow rate range. Accuracy may decrease at low and high flow rates. Therefore, selecting the appropriate ultrasonic flow meter model for the application is crucial.

[0011] Installation Location: Proper installation of the ultrasonic sensor is crucial. The sensor's position, angle, and distance all affect measurement accuracy. Incorrect installation may lead to signal attenuation or deflection.

[0012] However, in the process of monitoring and collecting flow, if the flow of the liquid fluctuates greatly, such as large surges or fluctuations occurring inside the liquid flow, the ultrasonic signal emitted by the ultrasonic flow meter will be greatly affected, thus affecting the stability of flow detection. Summary of the Invention

[0013] In view of this, the technical problem to be solved by the present invention is: how to provide a flow measurement and statistical method for ultrasonic detection to improve the statistical accuracy of ultrasonic flow detection according to different liquid flow states.

[0014] To achieve the above objectives, the present invention provides a flow measurement and statistical method for ultrasonic detection, comprising:

[0015] The first transmission time is determined by the first ultrasonic detection group, the second transmission time is determined by the second ultrasonic detection group, and the detected flow rate value is determined by the ultrasonic flow detection device.

[0016] The absolute value of the difference between the first transmission time and the second transmission time is determined as the transmission change duration. The relationship between the transmission change duration and the first preset duration and the second preset duration is determined. The first preset duration is less than the second preset duration. The first preset duration and the second preset duration are preset values.

[0017] If the transmission change duration is less than or equal to the first preset duration, then the detected traffic value is used as the traffic output value.

[0018] If the transmission change duration is longer than the first preset duration, then multiple detection flow values ​​are obtained at different sampling frequencies within the same sampling period, and the average value of the multiple detection flow values ​​is used as the flow output value.

[0019] Furthermore, along the flow direction of the liquid, the first ultrasonic detection group is located upstream of the ultrasonic flow detection device, and the ultrasonic flow detection device is located upstream of the second ultrasonic detection group.

[0020] Furthermore, the first ultrasonic detection group includes a first upper transducer and a first lower transducer, with the first upper transducer and the first lower transducer facing each other. The second ultrasonic detection group includes a second upper transducer and a second lower transducer, with the second upper transducer and the second lower transducer facing each other.

[0021] Furthermore, if the transmission change duration is greater than the first preset duration and less than the second preset duration, then the sampling frequency is the first frequency; if the transmission change duration is greater than the second preset duration, then the sampling frequency is the second frequency, and the first frequency is less than the second frequency.

[0022] Furthermore, if the transmission change duration is greater than the first preset duration and less than the second preset duration, then multiple detected traffic values ​​are obtained at the first frequency, and the average value of the multiple detected traffic values ​​is used to determine the traffic output value.

[0023] If the transmission change duration is greater than the second preset duration, then multiple detection traffic values ​​are obtained at the second frequency, and the average value of the multiple detection traffic values ​​is used to determine the traffic output value.

[0024] Furthermore, the line connecting the first upper transducer and the first lower transducer is perpendicular to the axial direction of the liquid flow along the pipeline, and the line connecting the second upper transducer and the second lower transducer is perpendicular to the axial direction of the liquid flow along the pipeline.

[0025] Furthermore, the ultrasonic flow detection device includes a forward transducer and a reverse transducer. Along the flow direction of the liquid, the forward transducer is located upstream of the reverse transducer, and the horizontal distance between the first upper transducer and the forward transducer is equal to the horizontal distance between the second lower transducer and the reverse transducer.

[0026] Compared with related technologies, the present invention proposes a flow measurement and statistical method for ultrasonic detection, which has the following advantages: by determining the transmission change duration by the sequential transmission time of the first and second ultrasonic detection groups set perpendicular to the liquid flow direction, the stability of the liquid flow state in the pipeline can be determined by the difference in the transmission change duration, and the flow value can be averaged by taking different sampling frequencies within the same sampling period according to different flow states to obtain the flow output value, thereby improving the accuracy of flow detection under different liquid flow states. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a flow measurement and statistics method for ultrasonic detection in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram showing the layout of the first ultrasonic detection group, the second ultrasonic detection group, and the ultrasonic flow detection device in an embodiment of the present invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] Please see Figure 1-2 As shown, the present invention provides a flow measurement and statistics method for ultrasonic detection, which includes: determining a first transmission time by a first ultrasonic detection group, determining a second transmission time by a second ultrasonic detection group, and determining the detected flow value by an ultrasonic flow detection device.

[0031] In this configuration, the first ultrasonic detection group is positioned upstream of the ultrasonic flow detection device, and the ultrasonic flow detection device is positioned upstream of the second ultrasonic detection group, meaning the ultrasonic flow detection device is positioned between the first and second ultrasonic detection groups.

[0032] Specifically, the ultrasonic flow detection device includes a forward transducer 11 and a reverse transducer 12, positioned upstream of the reverse transducer 12 along the flow direction of the fluid. These two transducers are typically installed at different locations in the pipeline, respectively, along the fluid flow direction. One transducer generates ultrasonic pulses and sends them into the fluid, with the ultrasonic pulses propagating at a specific frequency. The other transducer receives the ultrasonic pulse signals sent by its counterpart. The propagation speed of the ultrasonic pulses is affected by the fluid velocity and flow rate. By measuring the time difference between the transmitted and received ultrasonic pulses, the flow meter can calculate the fluid velocity. This time difference is commonly referred to as the "Doppler shift."

[0033] The first ultrasonic detection group includes a first upper transducer 21 and a first lower transducer 22, which are arranged facing each other. The second ultrasonic detection group includes a second upper transducer 31 and a second lower transducer 32, which are also arranged facing each other. By arranging the first upper transducer 21 and the first lower transducer 22, as well as the second upper transducer 31 and the second lower transducer 32, facing each other along the direction of liquid flow, the influence of obliquely arranged transducers on ultrasonic detection under both downstream and upstream flow conditions can be avoided.

[0034] By using the first upper transducer 21 and the first lower transducer 22, as well as the second upper transducer 31 and the second lower transducer 32, which are arranged vertically in front of each other, the flow fluctuation of the liquid when flowing through the first ultrasonic detection group and the second ultrasonic detection group can be accurately determined. That is, the time difference between the signal emitted by the first upper transducer 21 and the signal received by the first lower transducer 22 is used as the first transmission time, and the time difference between the signal emitted by the second upper transducer 31 and the signal received by the second lower transducer 32 is used as the second transmission time.

[0035] The fluctuation state of the liquid flow is determined by the difference between the first transmission time and the second transmission time. Specifically, the absolute value of the difference between the first transmission time and the second transmission time is used for judgment. If the liquid flow fluctuation is large, it will cause a large impact on the transmission of the ultrasonic signal in the pipeline, and thus the determined transmission change time will be large. If the liquid flow fluctuation is small or tends to be stable, the determined transmission change time will be small.

[0036] The line connecting the first upper transducer 21 and the first lower transducer 22 is perpendicular to the axis of the liquid flow along the pipe. The line connecting the second upper transducer 31 and the second lower transducer 32 is also perpendicular to the axis of the liquid flow along the pipe. The horizontal distance between the first upper transducer 21 and the forward transducer 11 is equal to the horizontal distance between the second lower transducer 32 and the reverse transducer 12.

[0037] This ensures that the first and second ultrasonic detection groups are located on both sides of the ultrasonic flow detection device and are equidistant, reducing the flow fluctuations that may occur over a longer range due to the different distances between the first and second ultrasonic detection groups, thus preventing errors in flow detection.

[0038] The absolute value of the difference between the first transmission time and the second transmission time is determined as the transmission variation duration. The relationship between the transmission variation duration and the first preset duration and the second preset duration is determined. If the first preset duration is less than the second preset duration, the first preset duration and the second preset duration are considered preset values. Different fluid transport states represented by different transmission variation durations are used for hierarchical processing, that is, the ultrasonic flow detection device acquires and collects the inspection flow rate value at different sampling frequencies within the same sampling period.

[0039] If the transmission change time is less than or equal to the first preset time, the detected flow rate value is used as the flow rate output value. That is, if the current liquid flow fluctuation is small, the detected flow rate value of the ultrasonic flow detection device can be directly output without calibration or adjustment.

[0040] If the transmission duration exceeds a first preset duration, multiple detected flow values ​​are acquired at different sampling frequencies within a sampling period of the same duration, and the average of these multiple detected flow values ​​is used as the flow output value. For example, the sampling period is 20s or 30s.

[0041] Specifically, if the transmission change duration is greater than a first preset duration but less than a second preset duration, the sampling frequency is the first frequency; if the transmission change duration is greater than the second preset duration, the sampling frequency is the second frequency. The first frequency is less than the second frequency. It should be noted that the first frequency or the second frequency refers to the number of samples taken within the same sampling period. The first frequency being less than the second frequency means that the number of samples corresponding to the first frequency within the same sampling period is less than the number of samples corresponding to the second frequency. The number of samples refers to the number of times the ultrasonic flow detection device performs a detection; one detection corresponds to one sampling.

[0042] If the transmission change duration is greater than a first preset duration but less than a second preset duration, multiple detected flow rates are acquired at a first frequency, and the average of these multiple detected flow rates is used to determine the flow output value. If the transmission change duration is greater than the first preset duration but less than the second preset duration, it indicates that current flow fluctuations exist but are small. Therefore, multiple detected flow rates are acquired at a first frequency within the same sampling period, and the average of these multiple detected flow rates is used as the flow output value. Averaging these multiple detected flow rates improves the flow detection accuracy within this sampling period.

[0043] If the transmission change duration exceeds the second preset duration, multiple detected flow rates are acquired at a second frequency, and the average of these multiple detected flow rates is used to determine the flow output value. This indicates that current flow fluctuations exist and are significant. Therefore, multiple detected flow rates are acquired at a second frequency within the same sampling period, and the number of acquired flow rates is greater than that acquired at the first frequency. The average of these multiple detected flow rates is used as the flow output value. By averaging these multiple detected flow rates, the flow detection accuracy within this sampling period can be improved, and the flow detection accuracy under significant flow fluctuations can also be improved simultaneously.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flow measurement and statistical method for ultrasonic detection, characterized in that, It includes: The first transmission time is determined by the first ultrasonic detection group, the second transmission time is determined by the second ultrasonic detection group, and the detected flow rate value is determined by the ultrasonic flow detection device. The absolute value of the difference between the first transmission time and the second transmission time is determined as the transmission change duration. The relationship between the transmission change duration and the first preset duration and the second preset duration is determined. The first preset duration is less than the second preset duration. The first preset duration and the second preset duration are preset values. If the transmission change duration is less than or equal to the first preset duration, then the detected traffic value is used as the traffic output value. If the transmission change duration is longer than the first preset duration, then multiple detection traffic values ​​are obtained at different sampling frequencies within the same sampling period, and the average value of the multiple detection traffic values ​​is used as the traffic output value. Along the flow direction of the liquid, the first ultrasonic detection group is located upstream of the ultrasonic flow detection device, and the ultrasonic flow detection device is located upstream of the second ultrasonic detection group; The first ultrasonic detection group includes a first upper transducer and a first lower transducer, with the first upper transducer and the first lower transducer facing each other. The second ultrasonic detection group includes a second upper transducer and a second lower transducer, with the second upper transducer and the second lower transducer facing each other. The line connecting the first upper transducer and the first lower transducer is perpendicular to the axial direction of the liquid flow along the pipeline, and the line connecting the second upper transducer and the second lower transducer is perpendicular to the axial direction of the liquid flow along the pipeline.

2. The flow measurement and statistical method for ultrasonic detection as described in claim 1, characterized in that, If the transmission change duration is greater than the first preset duration and less than the second preset duration, then the sampling frequency is the first frequency; if the transmission change duration is greater than the second preset duration, then the sampling frequency is the second frequency, and the first frequency is less than the second frequency.

3. The flow measurement and statistical method for ultrasonic detection as described in claim 2, characterized in that, If the transmission change duration is greater than the first preset duration and less than the second preset duration, then multiple detection traffic values ​​are obtained at the first frequency, and the average value of the multiple detection traffic values ​​is used to determine the traffic output value. If the transmission change duration is greater than the second preset duration, then multiple detection traffic values ​​are obtained at the second frequency, and the average value of the multiple detection traffic values ​​is used to determine the traffic output value.

4. The flow measurement and statistical method for ultrasonic detection as described in claim 1, characterized in that, The ultrasonic flow detection device includes a forward transducer and a reverse transducer. Along the flow direction of the liquid, the forward transducer is located upstream of the reverse transducer. The horizontal distance between the first upper transducer and the forward transducer is equal to the horizontal distance between the second lower transducer and the reverse transducer.

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