Large-caliber multi-channel flow passage partitioning and sound path connecting ultrasonic gas meter

Abstract

The present application belongs to the technical field of flow metering equipment, and particularly relates to an ultrasonic gas meter with large caliber, multi-channel flow channel partition and sound path connection, which aims to solve the problem that the prior art cannot realize the ultrasonic gas meter with a caliber exceeding DN500. The present application adopts the following arrangement: a plurality of cross sections are arranged in the pipe body of the gas meter, eight transducer mounting columns are radially arranged at the center of the pipe, a plurality of transducers can be mounted on each transducer mounting column, the transducers mounted on two rows of transducer mounting columns in parallel and adjacent to each other can be paired for measurement, the flow velocity through the interval is measured by time difference and calculated by an independent interval integration circuit PCB, the measurement results of a plurality of groups of transducers arranged according to the length of the flow meter pipe are obtained, the segmented measurement results are processed, the sound path connection of measurement is realized, and finally the total average flow velocity and total flow value of the flow meter are obtained; thus, the ultrasonic large-caliber gas metering is realized, and the maximum measurement range ratio is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of flow metering equipment, and specifically relates to a large-diameter, multi-channel ultrasonic gas meter with zoned flow paths and continuous sound path. Background Technology

[0002] In the era of the Internet of Things, big data, artificial intelligence, and industrial automation, the replacement of mechanical or electromechanical flow meters with fully electronic flow meters has become an irreversible trend in the field of industrial and public water, heat, and gas supply metering.

[0003] Based on practical application requirements, the fluid metering industry or applications expect standard flow metering instruments with good compatibility in terms of caliber specifications, low pressure loss, large range ratio, high accuracy, high reliability, no wear-prone components, good durability, and cost-effectiveness. In recent years, in the field of gas, especially fuel gas flow metering, thermal mass flow meters and ultrasonic flow meters, which are fully electronic and have good compatibility, have been put into use.

[0004] Since companies such as AMS (ACAM) and TI launched high-precision ASIC gas time difference timing chips (2012-2017), it has become possible to apply the time difference method of ultrasonic flow velocity measurement to gas flow measurement and metering and to promote its widespread application. One important application area is gas metering.

[0005] In the field of gas, especially fuel gas metering, mechanical gas flow meters are still widely used. These include diaphragm flow meters (mainly for small-diameter applications, such as residential use), turbine flow meters, Roots flow meters, and rotary impeller flow meters, while vortex flow meters, thermal flow meters, and ultrasonic flow meters are electronic flow meters.

[0006] In the field of gas metering, the application technology focuses more on the measurement or metering of flow rates in large-diameter gas pipelines. Compared with small and medium-diameter gas pipelines, large-diameter gas pipelines not only have larger diameters but also more uneven distribution of gas flow velocity within the pipeline, resulting in a wider range of variations in gas flow rate and requiring higher accuracy and a larger range ratio for gas flow measurement. Therefore, improving the accuracy and range ratio of flow measurement in large-diameter gas pipelines is technically much more difficult than in small and medium-diameter gas pipelines. The technical problem to be solved in this case is to determine which measurement method and flow meter structure should be adopted to achieve high accuracy and a large range ratio in flow measurement of large-diameter gas pipelines. The following is an overview and analysis of the technical background of flow measurement in large-diameter gas pipelines.

[0007] Membrane flow meters, turbine flow meters, Roots flow meters, and rotary flow meters, regardless of whether they operate on a volumetric or velocity-based principle, are all mechanical flow meters. According to their principle, mechanical flow meters measure fluid passively and require the fluid to provide kinetic energy. Their common drawbacks include short lifespan due to wear and a narrow measurement range due to the need for a certain amount of kinetic energy to drive them. In addition, their measurement accuracy will decrease as the service life extends.

[0008] Thermal mass flow meters, measured entirely electronically, have the significant advantages of directly measuring and quantifying the mass of a single gas stream, offering good compatibility with different pipe diameters and low pressure loss. However, based on the principle of sampling from a single point, they also have fatal flaws: 1) For large-diameter pipes, where gas velocity varies widely, setting only one or a few limited measurement points results in very limited accuracy; 2) When encountering water-containing gases, the measurement will become inaccurate, rendering it impossible to measure. Therefore, the application and promotion of this method is challenging in complex operating conditions.

[0009] Vortex flow meters, which measure flow rate entirely electronically, have the advantage that the measured volumetric flow rate is unaffected by parameters such as temperature, pressure, and density of the fluid being measured. However, for compressible gases with variable velocities, a single probe cannot accurately measure changes in the pipe conditions, resulting in significant measurement errors. Furthermore, vortex flow meters are limited by their poor resistance to vibration and contamination. In particular, they are restricted by the lower limit of the Reynolds number, preventing them from measuring low-velocity gases. Consequently, the range ratio of vortex flow meters is also relatively low, hindering their widespread application.

[0010] Ultrasonic flow meters measured electronically are velocity-type flow meters. Their time-of-flight measurement principle works as follows: In a flowing fluid, two ultrasonic transducers are arranged at regular intervals before and after the flow. The time difference required for the sound waves to travel upstream and downstream is extracted, and the fluid velocity is calculated by combining these measurements. Then, the flow rate is calculated based on the pipe cross-sectional area and the flow time. Therefore, measuring fluid velocity using the ultrasonic time-of-flight method is an active method; even if the velocity is zero, it does not affect normal measurement (for example, the temperature and density of the medium can be indirectly measured through the time difference). The ultrasonic velocity measurement sample is formed by the cylindrical space between the two transducers, not a single point. Therefore, if multiple pairs of transducers are arranged at different heights and orientations along the cross-section of the pipe, the fluid velocity can be measured representatively, comprehensively, and effectively. Furthermore, the sound velocity varies for media of different densities and temperatures. Therefore, with a fixed installation spacing between a pair of transducers, a calibrated flow meter can deduce and calculate the fluid density based on the ultrasonic sound velocity and the pipe pressure and temperature.

[0011] From the above explanation of several principles and implementations of using all-electronic methods to measure gas volume, it can be seen that flow velocity sampling of flowing fluids can be divided into two categories:

[0012] 1) Calculate volumetric flow rate using point-based velocity sampling: Take one or several points as representatives of the fluid velocity at cross-section S of a flowmeter with diameter D. Based on the relationship of velocity changes at these points, deduce the total velocity Vt at cross-section S of pipe diameter D, and the time T taken for the fluid to flow through the length L of the flowmeter pipe section. L Then, the fluid volume U it passes through L =S×Vt×T L Here, Vt is the only variable, and Vt exists at time T. L Everything inside is changing, so the volumetric flow rate U L The accuracy of the measured volume U depends on the accuracy of Vt, which in turn depends on the number and distribution of sampling points on a surface. Typically, due to limitations in sensor installation, the number of sampling points is small, resulting in a low accuracy of the measured volume U. L The accuracy is limited.

[0013] 2) Calculate volumetric flow rate using cylindrical volume as the basis for velocity sampling: The ultrasonic time-of-flight method for sampling and calculating velocity has actually obtained the average velocity within the cylindrical volume between the two transducers. The sampling time is Tx, here. The difference between Vt and 1) is that Vt is obtained through Tx. It is a definite value, while in T L Vt represents the change value. The diameter of the columnar sampling is the diameter d of the transducer, and the length of the columnar sampling is the distance between a pair of transducers. If multiple pairs of transducers can be easily laid out and installed inside the flowmeter pipe, and these transducers can be evenly distributed across the pipe cross-section, and if the sampling of multiple columnar volumes can represent the volume inside the flowmeter pipe, then this method of flow calculation is more reasonable. If the length of the flowmeter pipe section is L, since the sampling time Tx << T... L Therefore, the method of calculating flow velocity and thus volume using ultrasonic time-of-flight measurement is much more scientific and accurate than the method mentioned in 1). Furthermore, since Tx is in the nanosecond range, multiple samples can be taken and superimposed within one second for a changing fluid, resulting in an accurate flow rate value.

[0014] From the above sampling analysis of fluid volume calculation according to different principles, it can be seen that the ultrasonic time-of-flight method for sampling flow velocity is more accurate and reasonable. Furthermore, for a flow meter of a given length, the ultrasonic time-of-flight method for sampling flow velocity requires at least three aspects to be met for accurate and reasonable fluid volume calculation: (1) Multiple pairs of transducers need to be laid out and installed in the pipe of the flow meter, and these transducers can be rationally laid out according to the characteristics of the flow velocity distribution in the pipe and paired and placed on several sections of the pipe; (2) In order to ensure the stability and accuracy of the flow velocity provided by the transducers laid out in different positions, flow stabilization measures must be taken for the flow velocity in the flow channel, that is, the fluid is stabilized into a non-pulsating flow, which is more accurate; (3) Since the length of the flow meter is a fixed value, the paired transducers should be installed at both ends of the fluid inlet and outlet of the pipe as much as possible, so that the range of columnar volume sampling obtained is large and the maximum range ratio can be obtained.

[0015] Based on current practical applications, the three aspects mentioned above regarding improving large-diameter gas metering can be summarized into the following three principles:

[0016] (I) Multi-channel principle: To ensure high metering accuracy and reliability of large-diameter ultrasonic gas meters, sampling of large-diameter ultrasonic flow meters should be multi-directional, i.e., adopting a multi-channel mode (i.e., multiple sets of transducers combined for measurement). This is because, in addition to separately measuring and calculating the flow velocity of fluid at different heights and positions within the pipe, thus improving metering accuracy, the multi-channel mode is also an important guarantee of metering reliability. For example, even if one or more pairs of transducers stop working, the other transducers can still perform flow measurement.

[0017] (II) Adopting the principle of flow stabilization and ensuring the flowmeter's resistance to turbulence interference in the multi-channel sampling channel: As is well known, gas volume differs from liquid volume; it is compressible. Therefore, its flow velocity varies significantly at different locations within the pipe. Measures need to be taken to stabilize the flow velocity variation of the gas at different locations within the flowmeter pipe, ensuring a relatively stable representativeness so that a pair of transducers can sample more accurately and improve measurement accuracy. Furthermore, for flowmeter installation, the generally accepted standard is to ensure a 10:5 ratio upstream and downstream straight pipe section, i.e., ten times the length of the flowmeter at the front end and five times the length of the flowmeter at the rear end, to guarantee the effective range ratio and measurement accuracy of the flowmeter. This requirement is especially essential for flowmeters with larger diameters. However, in some special situations, especially when installed in confined spaces within pipe shafts, if there are bends at the front and rear ends, it becomes impossible to guarantee a 10 / 50 velocity distribution. As gas flows into the flow meter from these bends, the velocity distribution is severely biased to one side. For ultrasonic flow meters with insufficient channels in straight pipes, this leads to inaccurate velocity sampling, significantly reducing the flow meter's range ratio and measurement accuracy. This has been a persistent problem in the industry. If the requirement for straight pipe sections before and after the flow meter could be eliminated, it would provide a strong guarantee for the flow meter's application in various complex situations. This invention solves this problem using a grid-like partitioned structure, the principle of which is as follows:

[0018] Deduction and conclusions on the stability of flow velocity in parallel small-diameter pipes:

[0019] For fluid flow within a pipe, fluid mechanics states that the Reynolds number is a criterion for determining whether fluid flow is laminar or turbulent. It is a measure of the ratio of inertial force to viscous force, and it is a dimensionless number. When the Reynolds number is low, the influence of viscous force on the flow field is greater than that of inertial force. Disturbances in the flow velocity are attenuated by viscous force, resulting in stable, laminar flow. Conversely, when the Reynolds number is high, the influence of inertial force on the flow field is greater than that of viscous force. The fluid flow is less stable, accompanied by pulsations, and small changes in velocity easily develop and intensify, forming chaotic and irregular turbulent flow. A theoretical and experimental derivation is provided below:

[0020] Let the inner diameter of the large-diameter straight pipe be D, the velocity of the fluid inside the pipe be V, the density of the fluid be ρ, and the dynamic viscosity of the fluid be μ. Then the fluid flow area of ​​the large-diameter straight pipe is A = πD. 2 / 4. The mass flow rate of the fluid is G = AρV, and the Reynolds number of the fluid is Re = ρVD / μ. If the fluid from this large-diameter straight pipe is introduced into a combined flow channel consisting of n small-diameter straight pipes connected in parallel with a diameter d, and the total fluid flow rate of this combined flow channel is kept the same as the fluid flow rate of the large-diameter straight pipe, and the flow area of ​​this combined flow channel is kept to be Az = nπd 2 / 4 is the same as the fluid flow area A of the large-diameter straight pipe, i.e., A2 = A. Then the Reynolds number of the fluid in the small-diameter straight pipe d in the combined flow channel is: Therefore, when n > 1, we can draw the following conclusion:

[0021] In a combined flow channel, the Reynolds number Rez of the fluid in the small-diameter straight pipe (d) is less than the Reynolds number Re of the fluid in the large-diameter straight pipe (Re), i.e., Rez < Re. For example, if n = 9, then Rez = Re / 3. This reveals that the Reynolds number of the fluid in the small-diameter straight pipe (d) is smaller than that in the large-diameter straight pipe, meaning that the fluid flow in the small-diameter straight pipe (d) in a combined flow channel has higher stability, less pulsation, and more accurate ultrasonic measurement of fluid velocity. Especially when installing flow meters in confined spaces within pipe shafts, if there are bends at the front or rear, it's impossible to guarantee the strict requirement of a 10-unit length of straight pipe before and after the flow meter installation. However, the combined flow channel measurement method not only allows for automatic fluid rectification but also eliminates or reduces this strict requirement, improving measurement accuracy.

[0022] For a local grid cavity that undergoes partitioning, under stable laminar flow conditions, the velocity distribution is parabolic. By installing a transducer in the middle of the grid, the velocity in the middle of each partition can be used as a representative sampling point for velocity.

[0023] (III) For ultrasonic measurement, given the limited length of the flowmeter, the principle of maximizing the sound path is crucial. To ensure the ultrasonic gas meter has a large measurement range (range ratio) while meeting certain accuracy requirements, especially for large-diameter gas meters, maximizing the sound path between the ultrasonic transducers is extremely important. This is because a large range ratio is a critical indicator for trade settlement and is the most important technical specification for gas meters. For example, a factory might consume 500 times more gas during the daytime industrial production period than at night. If the flowmeter's range ratio is low, say R=200, then to consider the measurement of the large flow range during the day, the measurement of the small flow range at night must be neglected. In other words, the flowmeter may be unable to measure at low flow rates or have a large measurement error (negative accuracy, such as with mechanical turbine gas meters), inevitably causing measurement losses for the gas supplier. Therefore, to ensure the ultrasonic gas meter has a large range ratio and achieves fair trade settlement, the projected distance of the line connecting the two transducers of the ultrasonic gas meter in the airflow direction within the flowmeter's main pipe should be maximized to obtain a larger range ratio and a smaller starting flow rate.

[0024] Typically, the performance indicators of a flow meter are metering accuracy and range ratio. Metering accuracy is the ratio of the flow meter's measured flow rate to the actual flow rate. Improving fluid flow stability and batch production consistency are important conditions for determining metering accuracy. The range ratio is the ratio of the commonly used flow rate to the minimum flow rate under the condition of guaranteed flow metering accuracy. It reflects the range that can be accurately measured. Increasing the effective distance between ultrasonic transducers is a necessary condition for improving the range ratio. Therefore, the higher the metering accuracy and the larger the range ratio, the better the metering performance of the flow meter.

[0025] Obviously, after suppressing the influence of turbulence in the airflow process, the larger the range ratio, the better the metering performance of the flow meter. In this regard, there is a certain correlation between the volumetric flow rate Q of the ultrasonic flow meter and the range ratio R and the length L of the flow meter pipe (assuming it is the distance between a pair of transducers). In the field of metering, the range ratio R is defined as R = Q3 / Q1, where Q3 is the commonly used flow rate for a certain pipe diameter, which is a given value; Q1 is the minimum flow rate that meets certain metering accuracy requirements (for example, the metering accuracy of a two-stage flow meter is ±5%).

[0026] Through analysis and deduction, this case leads to an important conclusion: for the fluid passing through the flow meter pipeline, the measured starting flow rate Q... q The lower the minimum flow rate that the flow meter can sense and measure (corresponding to its flow velocity V), the better. q The lower the value, the lower the V. q (This is related to the resolution of the time-of-flight chip in the ultrasonic flow meter and the pipeline structure of the flow meter). Correspondingly, Q1 will also decrease proportionally (i.e., the corresponding minimum flow velocity V1 will decrease). Typically, in practical applications, its empirical value is Q1 = (5~10)Q q (Q1 varies depending on the ultrasonic flowmeter circuit and transducer, resulting in overall zero drift, and the water resistance design of the flowmeter pipeline.) Therefore, for a given flowmeter diameter (where the time interval between Q3 and Q1 flowing through the flowmeter pipeline is equal), the relationship between the range ratio R and the distance L between the two transducers can be derived as follows:

[0027]

[0028] In the above formula, Q3 is the commonly used flow rate of a certain diameter flow meter, V3 is the flow velocity of the fluid in the flow meter pipeline corresponding to Q3, Q1 is the minimum flow rate to meet certain measurement accuracy requirements, and V1 is the flow velocity of the fluid in the flow meter pipeline corresponding to Q1. For a certain diameter flow meter, Q3 and V3 are constants (selected values), π is pi, r is the inner radius of the flow meter pipeline, t is the measurement time, L is the distance between the opposing surfaces of the two transducers in the ultrasonic flow meter pipeline, α is the angle between the line connecting the two transducers in the direction of fluid flow in the flow meter pipeline (α is an acute angle; when α = 0, the line connecting the two transducers is in the same direction as the fluid flow, cos(α) = 1), k is a known quantity related to the measurement time difference and sound velocity of the flow meter, and β is a known quantity related to the measurement time difference and sound velocity of the flow meter. Let β = V3 / 10k, which is a constant, and V1 is calculated using the ultrasonic flow meter time difference formula. q The conclusion is that Therefore, in specific calculations, V1 is calculated as V1 = 10V q Substituting the values, we can draw the following conclusions from the above formula for R:

[0029] Increasing the projected distance L·cos(α) between the two transducers in the direction of fluid flow in the flowmeter pipeline can effectively improve the flowmeter's range ratio R.

[0030] Of the three principles mentioned above, the first two are relatively easy to implement, while the third is very difficult. The reason is as follows:

[0031] (1) The attenuation law of sound intensity propagating along the unidirectional x-axis is: I = I o e -2αx , where I o Let be the initial sound intensity, and α be the absorption attenuation coefficient (scattering attenuation is ignored here). Then... Where f is the sound wave frequency, β is the shear viscosity coefficient, thermal conductivity, isochoric specific heat, isobaric specific heat, and other parameters related to various processing methods of the medium, and ρ is the sound wave frequency. o Where C is density and C is the speed of sound.

[0032] (2) The higher the sound wave frequency f, the higher the measurement accuracy. Therefore, currently, for fluid measurement, f is 1-4 MHz for liquids and 0.2-0.5 MHz for gases; from I = I o e -2αx and It is known that the intensity of sound decays exponentially during propagation; the higher the frequency f, the greater the decay along the x-direction of propagation, and the greater the density ρ. o The smaller the speed of sound C, the greater the attenuation.

[0033] (3) According to current practical applications, for example, when f = 1MHz, a pair of transducers with a spacing of 1400mm can meet the measurement requirements for sound wave reception in water; however, for gases, such as air (or fuel gas), when f = 0.2MHz, for the same intensity of sound waves, a pair of transducers with a spacing of 100mm will receive sound intensity at the receiving end that is reduced to about 1 / 10 of the original; and if the pair of transducers is 300mm apart, and the excitation voltage of the transmitting transducer is set to 18V, the received sound wave signal can only barely meet the requirements for time difference measurement, and when the distance is greater than 300mm, the attenuated sound wave is almost impossible to identify and perform time difference measurement for the signal received by the transducer; according to I = I o e -2αx As the distance traveled in the direction of propagation increases, the exponential decay of sound waves becomes significant.

[0034] The above explains that when using ultrasonic metering, setting the transducer excitation voltage to 18V, a 1MHz transducer for water, and a flow meter with a transducer spacing of 1400mm (i.e., a DN1000 angled insertion type) can meet the requirements for signal recognition and metering. However, for natural gas, using a 0.2MHz transducer, for a DN200 angled insertion type gas flow meter, a transducer spacing of 280mm is barely sufficient to achieve gas flow metering for a DN150 angled insertion type. Therefore, in the field of ultrasonic gas metering, there is currently no information or data regarding the application of ultrasonic gas meters with larger diameters, such as DN300 and above (if the transducers are installed in an angled insertion configuration, the spacing between a pair of transducers is approximately 420mm and above).

[0035] In summary, given that the attenuation of ultrasonic waves propagating in gases is much greater than that in liquids, implementing large-diameter (e.g., larger than DN300) ultrasonic gas meters using the ultrasonic time-of-flight measurement principle presents a significant challenge in the gas metering industry and urgently needs to be addressed.

[0036] In the field of gas metering, the key to achieving the metering application of ultrasonic gas meters with large diameter (e.g., greater than DN300) and simultaneously realizing the goal of a large range ratio for flow meters lies in solving the problem of using ultrasonic waves to achieve long-distance flow velocity sampling and calculation within the same time interval.

[0037] Several existing structural methods for installing ultrasonic transducers on ultrasonic gas meters:

[0038] The installation method of the ultrasonic gas meter with oblique insertion transducer has the following characteristics: short sound path, few sound channels, and high precision requirements for oblique hole machining. For example, the authorization announcement number CN 211696533 U describes a base pipe structure for a large-diameter multi-channel oblique insertion through-beam ultrasonic flow meter. The projection distance of the line connecting the two transducers in the water flow direction in the pipe section is very short, which violates principle (III). In addition, when the pipe diameter is small, there is no space at the outer end of the pipe to install more sound channels, which violates principle (I). The machining angle of the oblique hole for installing the transducer is very high. If the deviation is small, the sound wave reception intensity will be greatly reduced for large diameters, so the machining is difficult.

[0039] Due to the variability and compressibility of gas volume, rectification should be performed within the gas flow pipeline of large-diameter ultrasonic gas meters to stabilize the fluid state. Patent announcements CN 210166007 U and CN 210071019 U both describe a base pipe structure for an ultrasonic flowmeter. For rectification, a honeycomb gas flow channel is installed only at a section of the inlet pipe, failing to achieve rectification across the entire flowmeter pipe section. The transducer is still installed using an oblique insertion method.

[0040] Patent application number CN 2021114261011 describes the structure of a multi-channel large-diameter ultrasonic water meter with a column-type transducer layered layout. Compared with the inclined transducer placement method, this structure allows for a larger spacing between a pair of transducers, and the transducers are also arranged at different heights, which improves the measurement accuracy and range ratio.

[0041] Patent application number CN 2021218819643 describes the structure of a large-diameter multi-channel zoned through-beam ultrasonic flow meter. Because the transducers are arranged in the flow channel, this solution has a larger spacing between a pair of transducers compared to the oblique insertion transducer arrangement and the column transducer arrangement. It achieves the following for ultrasonic flow measurement: (1) A pair of through-beam transducers are arranged in the direction of fluid flow, which can make full use of the effective sound path and is more conducive to the application of larger diameter flow meters; (2) Multi-channel, which meets the requirements of all-round measurement; (3) The flow channel zoned structure effectively stabilizes the fluid state and overcomes the influence of turbulence, etc. However, for a diameter of DN500 and a flow meter tube length of 600mm, the spacing between a pair of transducers is 550mm. It can measure normally in water, but it cannot be achieved in gas.

[0042] The above-mentioned methods of installing ultrasonic transducers in flow meters each have their own advantages and disadvantages in application. However, regardless of whether it is the transducer oblique insertion installation structure, the column installation structure, or the through-beam installation structure in the direction of fluid flow in the pipe, considering the safety of gas metering, and with the ultrasonic excitation voltage limited to a safe range, the application of gas metering cannot be realized when the diameter of the gas flow meter exceeds the range of signal reception and recognition between a pair of transducers.

[0043] In summary, based on the analysis of existing technologies for measuring pipeline gas flow, ultrasonic flow meters are the most reasonable and advanced method in the field of gas metering. However, for measuring gas flow in pipes, especially in large-diameter gas pipelines, existing technologies still have several shortcomings: the current placement methods of ultrasonic transducers in flow meters cannot meet requirements such as when the flow meter diameter is greater than DN300, or when maximizing the range ratio within the finite length of the flow meter. The technical objective of this invention is to overcome these shortcomings by developing a new structure for a large-diameter ultrasonic gas flow meter that meets the requirements of high accuracy and a large range ratio. Summary of the Invention

[0044] To address the aforementioned industry challenges, this paper proposes a large-diameter, multi-channel, flow-path-sequential ultrasonic gas meter. By utilizing the continuous sound path between a pair of ultrasonic transducers to extend the total effective sound path, it not only enables the metering of large-diameter gas flow meters but also maximizes the flow meter's range ratio. This solves the industry problem of difficulty in metering large-diameter gas meters (e.g., those larger than DN300). The technical solution is as follows:

[0045] The entire flow channel of a large-diameter or ultra-large-diameter flow meter is divided into a grid structure using a thin metal plate. Spindle-shaped transducer mounting columns are positioned by metal liners and partition plates, and secured by fixing heads. Multiple transducers can be installed on one or both sides of a single mounting column. Paired transducers are installed on two parallel rows of mounting columns on the same plane. An independent interval integration circuit PCB measures and calculates the flow velocity within each interval using time differences, obtaining the measurement results of multiple sets of transducers arranged according to the flow meter pipe length. Finally, the average flow velocity after the fluid passes through the complete cross-section and length of the flow meter is obtained, i.e., the average velocity within the measurement Δt time difference. Through this sound path continuation method, the total average flow velocity of the flow meter is finally obtained, and the total flow rate is derived.

[0046] The significant effects of implementing the above technical solutions are as follows: The entire flow channel of a large-diameter or ultra-large-diameter flowmeter is divided into a grid structure using a thin metal plate. Based on the deduction and conclusions regarding the stability of flow velocities in parallel small-diameter pipes, a stable laminar flow is formed within each small segmented cavity. Multiple transducers can be installed on one or both sides of a single transducer mounting column, with each transducer installed in the center of the small segmented cavity to form a stable laminar flow. The flow velocities measured by a pair of transducers are representative. The spindle-shaped cross-section of the transducer mounting column helps reduce fluid resistance and guide flow. The structure consists of a metal liner and partitions. The baffle is positioned and secured with a fixing head, ensuring the stability of the transducer mounting column's orientation and positioning. The segmented independent interval totalizing circuit PCB calculates the time difference measured by a pair of transducers in the interval between two parallel transducer mounting columns in the same plane to obtain the flow velocity value, and finally obtains the flow rate value of the flow meter. When the metering calculations of all segments are superimposed, an average flow velocity value that is almost equal to the total length of the flow meter is formed, and the total flow rate value is calculated from it. This can meet the metering requirements of large-diameter gas flow meters and maximize the flow meter's range ratio at the same time.

[0047] This invention relates to a large-diameter, multi-channel ultrasonic gas meter with zoned flow paths and continuous sound path. Its features include: an inlet flange and an outlet flange, a pipe sleeve, a mounting base, a metal liner, a grid-type partition plate, bidirectional mounting posts for the transducers, one unidirectional mounting post, two unidirectional mounting posts, a fixing head, a transducer, a vertical signal line cover, a horizontal signal line cover, a PCB for the interval integration circuit, and an instrument box. On the base pipe of the gas meter, which is connected by the inlet flange, the outlet flange, and the pipe sleeve, eight transducer mounting posts are installed radially in eight directions from the center of the pipe across the flow path cross-section of the large-diameter ultrasonic gas meter. The installation cross-section of these transducer mounting posts in the pipeline can have multiple... Each gas flow meter consists of two sections forming a group. On the two planes between each group, there are multiple pairs of transducer mounting columns. Each column can accommodate multiple transducers. Between the parallel, corresponding transducer columns and transducers in a single plane, a multi-channel, multi-combination flow velocity measurement system is formed. Pairs of transducers with different cross-sections and parallel to each other perform segmented measurements of the fluid within the total length of the gas flow meter's pipe casing. The results obtained along the pipe length are superimposed to form a continuous measurement path, ultimately yielding a total flow velocity measurement value and a calculated flow rate value. This not only enables the measurement of large-diameter gas flow meters but also achieves the maximum flow measurement range ratio even with a limited flow meter pipe length.

[0048] The partition plate is grid-shaped and installed inside the metal liner in a grid pattern with a certain spacing in the horizontal and vertical directions. It is connected to the inner wall of the metal liner by welding. The transducer is embedded in the transducer bidirectional mounting post or the transducer unidirectional mounting post. All three types of transducer mounting posts are positioned by the metal liner and the partition plate and are pressed and fixed by the fixing head. The metal liner is located inside the tube sleeve, and the two are positioned by the installed fixing head. The fixing head is located in the fixing seat on the tube sleeve. The transducer signal line runs from inside the transducer mounting post, through the hole in the fixing head, and through the horizontal and vertical signal line covers to the interval totalizing circuit PCB. The calculation result is transmitted through the signal cable and finally to the instrument box to connect with the total totalizing circuit PCB.

[0049] Furthermore, the inlet flange and outlet flange are located at both ends of the pipe sleeve, and have a fixing seat, an instrument box fixing column, a horizontal signal line cover, and a vertical signal line cover. They are connected to the pipe sleeve by laser welding or spot welding. The metal liner is located inside the pipe sleeve, and the gap between the two is very small. It is positioned and fixed by a fixing head.

[0050] The thickness of the partition plate is 1-3mm, which can be selected according to the diameter of the gas meter. The partition plate is connected to the inner wall of the metal liner by laser welding.

[0051] The transducer has a cylindrical, constant-diameter shape. Inside the transducer are ceramic plates, PCBs, negative electrode leads, positive electrode leads, and outgoing signal lines. The transducer is placed in the transducer mounting hole of the transducer mounting post. Its side is positioned by the cooperation of an external protruding post and an external protruding groove, and its lower part is positioned by a positioning platform. The two are bonded together with epoxy resin.

[0052] Transducer mounting posts can be divided into bidirectional mounting posts, unidirectional mounting posts (one type), and unidirectional mounting posts (two types), all made of engineering plastics such as PPS, PPO, PPA, and PA66. These mounting posts have a spindle-shaped cross-section, which guides the flow of fluid and reduces water resistance. Additionally, their positioning heads provide directional positioning. The bidirectional mounting posts are installed in the middle of the tube sleeve, while unidirectional mounting posts (one type and two types) are installed on either side of the tube sleeve. The transducer mounting holes on both sides of the bidirectional mounting posts are arranged in layers according to different heights. The transducers mounted on these posts are connected to the bidirectional, unidirectional, and unidirectional mounting posts in the same row. The transducers on column two are aligned in a straight line in the plane, forming a pair of opposing transducers. The positioning head of the transducer mounting column mates with the positioning hole one on the metal liner for directional positioning. The positioning column of the transducer mounting column inside the metal liner is inserted into the corresponding positioning hole two of the partition plate for cut-off positioning. The fixing seat is located on the outside of the tube sleeve, and the two are welded together. The fixing head is located in the fixing seat, and its height is positioned by the positioning surface one. The rubber ring two is located in the groove two at the lower end of the fixing head, which provides a sealing fit with the groove of the transducer column. The rubber ring one is located at the notch above the fixing head and provides a sealing function between the external thread nut and the inner side of the fixing seat.

[0053] The vertical signal line cover is located on the outside of the tube sleeve, covering the fixing seat to protect the outgoing signal line; the segmented vertical signal line covers are connected by cover connecting pieces.

[0054] The horizontal signal line cover is located on the outside of the pipe sleeve and is connected to the vertical signal line cover by laser spot welding. It is used to protect the interval totalizing circuit PCB. Inside the horizontal signal line cover, the interval totalizing circuit PCB is installed. It is used to calculate the time difference measured by each pair of transducers on a pair of transducer mounting posts. There are n interval totalizing circuit PCBs. Through signal lines, the flow velocity value or flow rate value is finally transmitted to the main control board in the instrument box.

[0055] The instrument box is fixed to the instrument box mounting post with screws; the instrument box mounting post is welded to the pipe sleeve; the section of the instrument box mounting post located inside the vertical signal line cover and the horizontal signal line cover has a hole to facilitate the passage of signal lines, which connect to the main control board inside the instrument box from inside the instrument box mounting post.

[0056] The transducer mounting columns and transducer layout are as follows: The transducer mounting columns are installed radially in eight directions according to the cross-section of the metal liner. Multiple sets of multi-channel transducers on them measure and calculate the flow velocity values ​​at different directions, positions, and heights by taking columnar samples from eight directions outward from the center of the pipe, at different planes within the two cross-sections of the pipe sleeve, and between different surfaces of the two transducers. These values ​​are then processed by their respective independent interval integration circuits (PCBs) and finally aggregated on the main control board in the instrument box to obtain the total metering data and flow rate value. From the longitudinal cross-section of the pipe sleeve, it can be seen that pairs of opposing transducers are arranged at different heights from top to bottom within the metal liner: Height 1, Height 2, Height 3, Height 4, Height 5, Height 6, Height 7, and Height 8.

[0057] Due to the short straight pipe sections or bends in the upstream connections where large-diameter gas meters are installed, localized turbulence is easily generated within the large-diameter pipe. A grid-style partition can effectively categorize and rectify this potential turbulence within the large pipe. Based on the conclusions regarding the velocity stability of parallel small-diameter pipes, this method achieves laminar flow. Since laminar flow velocities in pipes follow a parabolic distribution, meaning the velocity in the central region of the pipe is stable and representative, transducers are placed in the center of the grid to collect effective signals. Furthermore, since the velocity in the central region of the entire large-diameter pipe is stable, installing transducers around the perimeter of the central region effectively captures the velocity variations in that region.

[0058] The sound path continuity of this invention is achieved as follows: If three rows of transducer mounting columns are arranged longitudinally along the length of the flowmeter, and eight transducer mounting columns are arranged radially in eight directions in each row, forming two pairs of transducers, the time difference of the pairs of transducers in a plane is measured simultaneously to obtain the average flow velocity within their respective intervals. Then, the average of these two independent results is calculated to obtain the average flow velocity over the length of the entire flowmeter. Based on the cross-sectional area and pipe length, the volumetric flow rate can be calculated. Since the flow velocity measurement is completed within a time interval Δt (this interval is on the nanosecond level), and multiple measurements can be taken within one second (e.g., ten times), the obtained flow velocity change rate and average flow rate are quite accurate. For example, the flowmeter pipe section is divided into two equal segments, the sum of which is close to the pipe length, denoted by L. The interval m between a pair of transducers is close to 1 / 2 the pipe length, and the total length between the two pairs of transducers is close to L, i.e., 2m≈L. Therefore, according to the relationship between the range ratio R and the distance L between the two transducers: R=β·L·cos(α), in this invention, the angle α between the line connecting a pair of transducers and the direction of fluid flow in the pipe is 0, and the line connecting the two transducers is consistent with the direction of fluid flow, cos(α)=1, so R=β·L. Thus, it can be seen that the continuity of the sound path is realized. This not only realizes the measurement of large-diameter gas flowmeters, but also obtains the maximum value of the flow measurement range ratio under the condition of limited flowmeter pipe length.

[0059] In summary, this invention utilizes the layout of transducer mounting columns to achieve continuous ultrasonic path through the longitudinal arrangement of multiple sets of transducer mounting columns, ensuring that the effective signal reception range of a pair of transducers is maintained. This enables the metering of large-diameter or ultra-large-diameter (greater than DN300) gas meters, while simultaneously maximizing the range ratio of the gas meters, thus solving the problem of a shortage of ultra-large-diameter gas meters. Compared with existing technologies, this invention achieves the technical improvements proposed in the technical solution, demonstrating substantial and significant progress, as shown in:

[0060] The significant effects of implementing the above technical solutions are as follows: the flow channel of large-diameter or ultra-large-diameter flowmeters is divided into a grid structure using thin metal plates. Based on the deduction and conclusions of the stability of flow velocity in parallel small-diameter pipes, a stable laminar flow is formed in each small segmented cavity; multiple transducers can be installed on one or both sides of a transducer mounting column, with each transducer installed in the center of the small segmented cavity to form a stable laminar flow, and the measured flow velocity is representative; the spindle-shaped transducer mounting column is positioned by metal liner and partition plates, and is pressed and fixed with a fixing head, ensuring the stability of the direction and positioning of the transducer mounting column; the segmented independent interval integration circuit PCB measures the time difference between the intervals of two transducer mounting columns, and finally obtains the flow value of the flowmeter. When the metering of all segments is superimposed and calculated, a sound path that is almost equal to the length of the flowmeter is formed, which can realize the metering requirements of large-diameter gas flowmeters and maximize the range ratio of the flowmeter at the same time.

[0061] First, due to the change in the transducer installation method, the present invention can divide the flow channel of a large-diameter ultrasonic gas meter into a mesh structure using a thin metal plate, thereby forming a stable laminar flow in the small segmented cavity, which facilitates the measurement of representative flow velocity parameters in the mesh.

[0062] Second, the transducers are installed using transducer mounting columns with a spindle-shaped cross-section, which minimizes water resistance and facilitates fluid flow. Multiple transducers can be installed on each transducer mounting column. The transducers are cylindrical with a uniform diameter, which helps reduce the thickness of the transducer mounting columns. The transducer mounting columns are positioned by metal liners and partition plates to ensure the correct installation direction of the transducers.

[0063] Third, in the flow channel section of the large-diameter ultrasonic gas meter, eight transducer mounting columns are installed in a radial layout radiating outwards in eight directions from the center of the pipe. There can be multiple sets of such transducer mounting columns in the pipeline; multiple transducers can be installed on each transducer mounting column. Between the transducer columns and transducers that are parallel and side by side in a plane, a flow velocity measurement channel is formed, and the measurement is in multiple combination forms.

[0064] Fourth, the transducers on the transducer mounting column are measured and calculated on different planes within two cross sections of the tube sleeve to obtain the velocity variation values ​​at different directions, positions, and heights.

[0065] Fifth, within the length of the gas flow meter's tube sleeve, because ultrasonic waves attenuate significantly in gas and have a short propagation distance, it is necessary to install multiple transducer mounting columns on a plane parallel to each other on the cross-section of the tube sleeve, based on the sound wave intensity and its attenuation law. The distance between two adjacent planes must meet the requirements for sound wave reception intensity and measurement. Multiple transducers are installed on the corresponding transducer mounting columns between the planes. In this way, the fluid within the total length of the flow meter's tube sleeve can be measured in segments within the same time period, i.e., several nanoseconds, and a total measurement value can be obtained. According to R = β·L·cos(α), where cos(α) = 1, therefore R = β·L, it can be seen that due to this continuity of sound path, not only is the measurement of large-diameter gas flow meters realized, but also the flow measurement range ratio is maximized under the condition of limited flow meter pipe length. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the appearance of a large-diameter, multi-channel ultrasonic gas meter with zoned flow paths and continuous sound path.

[0067] Figure 2 This is a cross-sectional view of the flow channel partitioning and the location of the transducer mounting column in a large-diameter gas meter.

[0068] Figure 3 This is a schematic diagram of a cylindrical constant-diameter transducer;

[0069] Figure 4 This is a cross-sectional view of a cylindrical constant-diameter transducer;

[0070] Figure 5 This is a cross-sectional view of a transducer mounting column structure where the transducer can be installed bidirectionally.

[0071] Figure 6 This is a schematic diagram of a transducer mounting column with a unidirectional transducer installation.

[0072] Figure 7 This is a cross-sectional view of a transducer mounting column with a unidirectional transducer installation.

[0073] Figure 8 This is a schematic diagram of a transducer mounting column with a unidirectional transducer installation.

[0074] Figure 9 This is a schematic diagram showing the relationship between the positioning head and the positioning hole of a transducer mounting post.

[0075] Figure 10 This is a sectional view of the installation and positioning of the transducer mounting column in the large-diameter table;

[0076] Figure 11 This is a sectional view of the fixed head;

[0077] Figure 12 This is a cross-sectional view showing the relationship between the transducer mounting post, fixing head, external threaded pressure ring position and the metal liner and tube sleeve.

[0078] Figure 13 This is a schematic diagram showing the height position of the transducer on the transducer mounting column;

[0079] Figure 14 This is a cross-sectional view showing the positional relationship between the transducer mounting post, the PCB of the interval integration circuit, and the horizontal signal line cover.

[0080] Figure 15 It is a sectional view showing the positional relationship of five sections and eight transducer mounting columns in a large-diameter gas meter;

[0081] Figure 16 It is a cross-sectional view showing the positional relationship of the five-section transducer mounting columns arranged in four intervals in a large-diameter gas meter.

[0082] In the picture:

[0083] 11. Inlet flange; 12. Outlet flange; 25. Pipe sleeve; 251. Fixing base; 22. Metal liner; 23. Partition plate; 24. Diagonal support; 221. Positioning hole one; 222. Positioning hole two; 30. Bidirectional mounting post; 31. Unidirectional mounting post one; 32. Unidirectional mounting post two; 311. Positioning post; 312. Wiring hole; 313. Transducer mounting hole; 3131. Positioning platform; 3132. External protrusion; 314. Guide surface; 315. Positioning head; 316. Groove one; 36. Fixing head; 37. External thread nut; 3601. Notch; 3602. Central hole; 3603. Positioning surface two; 3604. Hollow post; 3605. Groove two; 3 61. Rubber ring one; 362. Positioning surface one; 363. Rubber ring two; 313. Transducer mounting hole; 33. Transducer; 333. Signal line; 331. Ceramic plate; 332. PCB; 3312. Negative electrode lead; 3313. Positive electrode lead; 337. U-shaped notch; 339. Outer protrusion; 3302. Bottom surface; A1. Height one; A2. Height two; B1. Height three; B2. Height four; C1. Height five; C2. Height six; D1. Height seven; D2. Height eight; 44. Vertical signal line cover; 441. Cover connecting piece; 442. Horizontal signal line cover; 4421. Interval integration circuit PCB; 55. Instrument box; 56. Instrument box fixing post. Detailed Implementation

[0084] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0085] Example 1:

[0086] This embodiment is a DN800 large-diameter multi-channel flow channel partitioning and sound path continuity ultrasonic gas meter.

[0087] As attached Figure 16 , 1 As shown, this embodiment specifically describes a large-diameter, multi-channel ultrasonic gas meter with DN800, transducer mounting columns, and transducers arranged in four sections across the flow channel cross-section, featuring continuous sound path. Its features include: an inlet flange 11 and an outlet flange 12, a pipe sleeve 25, a fixing base 251, a metal liner 22, a partition plate 23, a bidirectional mounting column 30 for the transducer, a unidirectional mounting column one 31, a unidirectional mounting column two 32, a fixing head 36, a transducer 33, a vertical signal line cover 44, a horizontal signal line cover 442, and a section integration circuit PCB. 4421, Instrument Box 55; On the base pipe of the gas meter, which is connected by an inlet flange, an outlet flange, and a pipe sleeve, eight transducer mounting columns are installed radially in eight directions from the center of the pipe across the flow channel section of the large-diameter ultrasonic gas meter. These transducer mounting columns can have multiple installation sections in the pipeline; this embodiment has five sections, with two sections forming a group, for a total of four groups. If the distance between each group of transducers is 260mm, the received acoustic signal at its receiving end meets the measurement requirements (this distance can be adjusted according to actual test results). There are multiple pairs of transducer mounting columns, and multiple transducer mounting columns can be installed on each transducer mounting column. A number of transducers, arranged in parallel pairs on the same plane, form a multi-channel, multi-combination flow velocity measurement system. With pairs of transducers of different cross-sections, parallel to each other and on the same plane, the fluid within a 1200mm total length of the gas flow meter pipe is measured in segments. The results obtained along the pipe length are superimposed to form a measurement path of 4 × 260 = 1040mm. Finally, a total flow velocity measurement value and a calculated flow rate value are obtained over a 1040mm length. This not only enables the measurement of large-diameter gas flow meters but also maximizes the flow measurement range ratio within the limited length of the flow meter pipe.

[0088] As attached Figure 15 , 12As shown in Figure 14, the partition plate 23 is grid-shaped and installed inside the metal liner 22. It is arranged in a grid pattern with a certain spacing in the horizontal and vertical directions and is connected to the inner wall of the metal liner by welding. The transducer 33 is embedded in the bidirectional mounting post, the unidirectional mounting post 1 31 and the unidirectional mounting post 2 32 of the transducer. All three types of transducer mounting posts are positioned by the metal liner 22 and the partition plate 23 and are pressed and fixed by the fixing head 36. The metal liner 22 is located inside the tube sleeve 25 and the two are positioned by the installed fixing head 36. The fixing head is located in the fixing seat 251 on the tube sleeve 25. The transducer signal line 333 is connected to the interval totaling circuit PCB 4421 from the several transducer mounting posts, through the fixing head hole, the horizontal signal line cover 442 and the vertical signal line cover 44. Its calculation result is finally connected to the instrument box 55 and the total totaling circuit PCB by the signal cable.

[0089] Furthermore, the inlet flange 11 and outlet flange 12 are located at both ends of the pipe sleeve 25, respectively, and have a fixing seat 251, an instrument box fixing post 56, a horizontal signal line cover 442, and a vertical signal line cover 44 on them. They are connected to the pipe sleeve by laser welding. The metal liner 22 is located inside the pipe sleeve 25, and the gap between the two is very small. It is positioned and fixed by the fixing head 36.

[0090] The partition plate 23 has a thickness of 2mm, which can be selected according to the diameter of the gas meter. The partition plate is connected to the inner wall of the metal liner by laser welding.

[0091] The transducer 33 has a cylindrical shape with a constant diameter. Inside the transducer are ceramic plates 331, PCB 332, negative electrode leads 3312, positive electrode leads 3313, and outgoing signal lines 333. The transducer is placed in the transducer mounting hole 313 on the transducer mounting post. Its side is positioned by the cooperation of the external protruding post 339 and the external protruding groove 3132. Its lower part is positioned by the positioning platform 3131. The two are bonded together with epoxy resin.

[0092] As attached Figure 5 , 6As shown in Figures 7, 8, and 9, the transducer mounting columns can be divided into bidirectional mounting columns 30, unidirectional mounting column one 31, and unidirectional mounting column two 32, which are made of engineering plastics such as PPS, PPO, PPA, and PA66. These mounting columns have a spindle-shaped cross-section, which guides the flow of fluid to reduce water resistance. Additionally, their positioning heads 315 provide directional positioning. The bidirectional mounting column 30 is installed in the middle of the tube sleeve 25, while the unidirectional mounting columns one 31 and two unidirectional mounting columns 32 are installed on both sides of the tube sleeve. The transducer mounting holes 313 on both sides of the bidirectional mounting column are arranged in layers according to different heights. The transducers 33 installed on it correspond linearly in the plane to the transducers on the bidirectional mounting columns, unidirectional mounting column one, and unidirectional mounting column two installed in the same row. A pair of opposing transducers are formed; the positioning head 315 of the transducer mounting post cooperates with the positioning hole 221 on the metal liner 22 for directional positioning; the positioning post 311 of the transducer mounting post located inside the metal liner penetrates into the corresponding positioning hole 222 of the partition plate 23 for cut-off positioning; the fixing seat 251 is located on the outside of the tube sleeve 25, and the two are welded together; the fixing head 36 is located in the fixing seat 251, and is positioned by the positioning surface 362 and tightened by the external thread nut 37; the second rubber ring 363 is located in the groove 3605 at the lower end of the fixing head, and plays a sealing role with the groove 316 of the transducer post; the first rubber ring 361 is located at the notch 3601 above the fixing head, and plays a sealing role with the external thread nut 37 and the inner side of the fixing seat 251.

[0093] The vertical signal line cover 44 is located outside the tube sleeve 25 and covers the fixing seat 251 to protect the outgoing signal line 333; the segmented vertical signal line covers are connected by cover connecting pieces 441.

[0094] The horizontal signal line cover 442 is located on the outside of the tube sleeve 25 and is connected to the vertical signal line cover by laser spot welding. It is used to protect the interval totalizing circuit PCB 4421. Inside the horizontal signal line cover, the interval totalizing circuit PCB is installed. It is used to calculate the time difference measured by each pair of transducers on a pair of transducer mounting posts. There are n interval totalizing circuit PCBs. Through signal lines, the flow rate value or flow volume value is finally transmitted to the main control board in the instrument box 55.

[0095] The instrument box 55 is fixed to the instrument box fixing post 56 with screws; the instrument box fixing post is welded to the pipe sleeve, and the section of the instrument box fixing post located inside the vertical signal line cover and the horizontal signal line cover has a hole to facilitate the passage of the signal line, which connects from the instrument box fixing post to the main control board inside the instrument box.

[0096] As attached Figure 13As shown, the transducer mounting column and the layout of the transducers are as follows: The transducer mounting column is installed radially in eight directions according to the cross-section of the metal liner 22. Multiple sets of multi-channel transducers 33 on it are used to measure and calculate the flow velocity values ​​in different directions, positions and heights in eight directions inside the pipe, in different planes in two cross-sections of the pipe sleeve, and between different surfaces of two transducers by columnar sampling. The flow velocity values ​​are calculated by their respective independent interval integration circuits PCB 4421 and finally summarized on the main control board in the instrument box 55 to obtain the total metering data and flow value. From the longitudinal cross-section of the pipe sleeve, it can be seen that the pairs of opposing transducers are arranged in the metal liner 22 at different heights from top to bottom as follows: Height 1 A1, Height 2 A2, Height 3 B1, Height 4 B2, Height 5 C1, Height 6 C2, Height 7 D1, Height 8 D2.

[0097] Due to the short straight pipe sections or bends in the upstream connections where large-diameter gas meters are installed, localized turbulence is easily generated within the large-diameter pipe. A grid-style partition can effectively categorize and rectify this potential turbulence within the large pipe. Based on the conclusions regarding the velocity stability of parallel small-diameter pipes, this method achieves laminar flow. Since laminar flow velocities in pipes follow a parabolic distribution, meaning the velocity in the central region of the pipe is stable and representative, transducers are placed in the center of the grid to collect effective signals. Furthermore, since the velocity in the central region of the entire large-diameter pipe is stable, installing transducers around the perimeter of the central region effectively captures the velocity variations in that region.

[0098] The sound path continuity of this invention is achieved as follows: If five rows of transducer mounting columns are arranged longitudinally along the length of the flowmeter, and eight transducer mounting columns are arranged radially in eight directions in each row, forming four pairs of transducers, these four pairs of transducers simultaneously measure the time difference to obtain their respective average flow velocity. Then, in the instrument box, the two independent results are averaged to obtain the average flow velocity over the entire length of the flowmeter. Based on the cross-sectional area and pipe length, the volumetric flow rate can be calculated. Since the flow velocity measurement is completed within a time interval Δt (this interval is on the nanosecond level), and in this embodiment, six measurements are taken within one second, the obtained flow velocity change rate and average flow rate are quite accurate.

[0099] In this embodiment, the flowmeter pipe section is divided into 4 equal segments, the sum of which is 1040mm, which is close to the pipe length of 1200mm, denoted by L. For the interval m between a pair of transducers, the total length L between the 4 pairs of transducers is determined by the relationship between the range ratio R and the distance L between the two transducers: R = β·L·cos(α). In this invention, the angle α between the line connecting a pair of transducers and the direction of fluid flow in the pipe is 0, and the line connecting the two transducers is consistent with the direction of fluid flow, so cos(α) = 1. Therefore, R = β·L. Thus, the continuity of the sound path is achieved. This not only enables the measurement of large-diameter gas flowmeters, but also maximizes the flow measurement range ratio under the condition of limited flowmeter pipe length.

[0100] The above examples illustrate the implementation and application of the present invention, a DN800 large-diameter multi-channel flow path partitioned and sound path continuous ultrasonic gas meter. However, it is not limited to the specific embodiments described above. If the size and frequency of the transducer ceramic plate are changed, the present invention is also applicable to the field of liquid metering. Any modifications or variations made based on the content of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A large-diameter, multi-channel ultrasonic gas meter with zoned flow paths and continuous sound path, characterized in that: The gas meter base pipe, which is formed by connecting the inlet flange (11), outlet flange (12), and pipe sleeve (25), is divided into sections (23), including inlet flange (11), outlet flange (12), pipe sleeve (25), fixing seat (251), metal liner (22), partition plate (23), bidirectional mounting column (30), unidirectional mounting column one (31), unidirectional mounting column two (32), fixing head (36), transducer (33), vertical signal line cover (44), horizontal signal line cover (442), interval totaling circuit PCB (4421), and meter box (55). A partition plate (23) is installed inside the pipe sleeve (25) of the gas meter, which is connected by the inlet flange (11), outlet flange (12), and pipe sleeve (25). The partition plate (23) is 1-3 mm thick and is installed inside the metal liner (22). It is arranged in a grid pattern with a certain spacing in the horizontal and vertical directions. A super-powered gas meter is installed within the grid channel formed by each section. The acoustic measurement channel is constructed by installing eight transducer mounting columns radially around the center of the gas meter pipe on several cross sections. The unidirectional mounting column one (31) and unidirectional mounting column two (32) are located on the inner sides of both ends of the pipe sleeve (25), while the bidirectional mounting column (30) is located in the middle of the inner side of the pipe sleeve (25). Several transducers can be installed on each transducer mounting column. The transducers installed on two rows of parallel and adjacent transducer mounting columns on the same plane can be paired and measured. The flow velocity of the interval is measured and calculated by an independent interval integration circuit PCB (4421) through time difference. The measurement results of multiple sets of transducers arranged according to the length of the flow meter pipe are obtained. The segmented measurement results are processed to realize the continuity of the acoustic path of the measurement. Finally, the total average flow velocity and total flow value of the flow meter are obtained. Thus, the ultrasonic metering of large-diameter gas is realized and the measurement range ratio is maximized.

2. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that: The partition plate (23) is connected to the inner wall of the metal liner (22) by welding.

3. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that: The cross-sections of the unidirectional mounting column one (31), unidirectional mounting column two (32) and bidirectional mounting column (30) are spindle-shaped.

4. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that: The positioning head (315) on the one-way mounting post (31), one-way mounting post (32) and two-way mounting post (30) cooperates with the positioning hole (221) on the metal liner (22) for positioning; the positioning post (311) is inserted into the positioning hole (222) of the partition plate (23) for cut-off positioning.

5. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that... The fixing seat (251) is located on the outside of the tube sleeve (25), and the two are welded together; the fixing head (36) is located in the fixing seat (251), and is positioned by the first positioning surface (362) and tightened by the external thread nut (37); the second rubber ring (363) is located in the second groove (3605) at the lower end of the fixing head (36), and is sealed with the first groove (316) of the transducer column; the first rubber ring (361) is located at the notch (3601) above the fixing head.

6. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that... The transducer (33) is cylindrical with a constant diameter. Inside the transducer are ceramic plates (331), PCB (332), negative electrode leads (3312), positive electrode leads (3313) and signal lines (333). The transducer (33) is located in the transducer mounting hole (313). The side is positioned by the cooperation of the external protrusion post (339) and the external protrusion groove (3132). The lower part is positioned by the positioning platform (3131). The two are bonded together with epoxy resin.

7. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that... The vertical signal line cover (44) is located on the outside of the tube sleeve (25), and the segmented vertical signal line covers are connected by cover connecting pieces (441); the horizontal signal line cover (442) is located on the outside of the tube sleeve (25), and is connected to the vertical signal line cover by laser spot welding.

8. The ultrasonic gas meter with large-diameter multi-channel flow path partitioning and continuous sound path as described in claim 1, characterized in that... The transducers (33) are arranged in the metal liner (22) at different heights from top to bottom as follows: height 1 (A1), height 2 (A2), height 3 (B1), height 4 (B2), height 5 (C1), height 6 (C2), height 7 (D1), and height 8 (D2).

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