Large-diameter multi-channel flow channel partition correlation type ultrasonic gas flowmeter

Abstract

The invention belongs to the technical field of flow metering equipment, particularly relates to a large-caliber multichannel flow channel partition correlation type ultrasonic gas flowmeter, and aims to solve the problem that in the prior art, correlation installation in a four-channel transducer partition pipeline with the caliber smaller than or equal to DN100 cannot be achieved under the condition that the pressure loss condition of the flowmeter is met. According to the invention, paired opposite transducers are independently arranged in respective separated fixing seats in the section of a flow channel in a partitioned manner, so that the proportion of the fixing seats and outgoing line channels of the transducers occupying the section of the flow channel is reduced, and the pressure loss of the flow meter is reduced; while the range ratio of the gas flow meter is maximized, the application target of the gas flow meter which is installed in a partition correlation mode in a large-diameter four-channel transducer pipeline 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 flow channel partitioned through-beam super gas flow meter. 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, low pressure loss, large range ratio, high accuracy, high reliability, no wear-prone components, good durability, and cost-effectiveness. In recent years, thermal mass flow meters and ultrasonic flow meters have shown good compatibility and are already in use in the field of all-electronic mode for gas flow metering, especially for gas flow metering.

[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 promote its 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 have larger pipe diameters and uneven distribution of gas flow velocity within the pipeline, resulting in a wider range of gas flow distribution and variation. Therefore, the total flow measurement must be able to follow the distribution of the fluid flowing within the pipeline to achieve more accurate measurement and a higher range ratio. It is evident that improving the accuracy and range ratio of flow measurement in large-diameter gas pipelines is much more technically challenging than that in small and medium-diameter gas pipelines. The technical problem to be solved in this case is to determine which measurement method and flowmeter 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 their principle is volumetric or velocity-based, 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 are short lifespan due to wear and changes in mechanical damping, and a very low measurement range ratio because they require the fluid's kinetic energy to drive them.

[0008] Thermal mass flow meters, measured entirely electronically, rely on the linear relationship between flow velocity, temperature, and resistance. Their key advantages include direct measurement of gas mass flow rate for single-component gases, good compatibility with different pipe diameters, and low pressure loss. However, based on the principle of single-point sampling, they have fatal flaws: 1) For large-diameter pipes with wide gas velocity variations, the accuracy of measurements is very limited if only one or a few measurement points are set; 2) When encountering water-containing gases, the measurement will be inaccurate, making measurement impossible; 3) They can only measure the flow rate of single-component gases, not multi-component gases, especially those with varying compositions. Therefore, the application and promotion of this method is difficult 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 across the cross-sectional area S of a flowmeter with diameter D. Based on the relationship between the velocity changes at these points, derive the total velocity Vt across the pipe diameter D and cross-sectional area S, and the time T it takes for the fluid to flow through the length L of the flowmeter pipe section. L Then, it passes through the fluid volume U inside the pipe. L =S×Vt×T L Here, Vt is the only variable, and Vt is constant 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 pipe cross-section. Typically, due to limitations in sensor installation, the number of sampling points is small, resulting in an inaccurate measurement of the 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 actually obtains the average velocity within the cylindrical volume between the two transducers through velocity sampling and calculation. The sampling time is Tx, where 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 deriving volume using the ultrasonic time-of-flight method 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 a more accurate flow rate value.

[0014] From the above sampling analysis of fluid volume calculation based on 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, to accurately and reasonably calculate the fluid volume using the ultrasonic time-of-flight method for flow velocity sampling, at least two aspects must be met: (1) Multiple pairs of transducers need to be laid out and installed in the flow meter's pipe, 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 one or more cross 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 channel, that is, the fluid must be stabilized into a non-pulsating flow, and such sampling is more accurate.

[0015] Regarding the two aspects mentioned above for improving large-diameter gas metering, based on current practical applications, the following eight principles can be summarized:

[0016] (I) The Principle of Maximizing the Range Ratio: To ensure that ultrasonic gas meters have a large measurement range (range ratio) while meeting certain accuracy requirements, especially for large-diameter gas meters, maximizing the acoustic path between ultrasonic transducers (i.e., maximizing the range ratio) is extremely important. This is because a large range ratio is a crucial indicator for trade settlement and is also the most important technical specification of a gas meter. For example, a manufacturing plant consumes 500 times more gas during the daytime industrial production period than at night. If the flow meter's range ratio is low, such as 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 flow meter may be unable to measure at small flow rates or have a large measurement error (accuracy value is negative, such as in mechanical turbine gas meters), which will inevitably cause measurement losses for the gas supplier. Therefore, to ensure that ultrasonic gas flow meters have a large range ratio and achieve fair trade settlement, the projected distance of the line connecting the two transducers of the ultrasonic gas meter in the airflow direction within the flow meter's main pipe should be maximized to obtain a larger range ratio and a smaller starting flow rate. This principle is also the most important indicator for all flow meters.

[0017] (II) Multi-channel zoned flow stabilization and anti-turbulence principle: 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 are needed to stabilize the velocity variation of the gas at different locations within the flowmeter pipe, ensuring a relatively stable representativeness. This allows the transducers to sample more accurately, improving measurement precision. Furthermore, the generally accepted standard for flowmeter installation is to ensure a 10:5 length difference between the upstream and downstream straight pipe sections. This ensures stable fluid flow and guarantees the effective range ratio and measurement accuracy of the flowmeter. This requirement is essential, especially for flowmeters with larger diameters. However, in certain 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. Consequently, when gas flows into the flow meter from the bend, its velocity distribution is severely biased to one side. For ultrasonic flow meters with insufficient sound 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 environments.

[0018] (III) Transducer Through-beam Installation Principle: In through-beam installation, the acoustic signal is directly transmitted and received between a pair of transducers, resulting in the strongest effective signal amplitude. Large-diameter flow meters are relatively large; to ensure signal reception strength, through-beam installation should be selected for the transducers. Furthermore, among various through-beam installation methods, the installation method that aligns with the water flow direction—that is, placing a pair of transducers inside the flow meter pipe and aligning them with the fluid flow direction—maximizes the acoustic path between the two transducers.

[0019] (iv) Multi-channel principle: To ensure high measurement accuracy and reliability of large-diameter ultrasonic gas flow meters, sampling should be multi-directional, i.e., using a multi-channel mode (i.e., multiple transducer combinations 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 measurement accuracy, the multi-channel mode is also an important guarantee of measurement reliability. For example, even if one or more pairs of transducers stop working, the other transducers can still perform flow measurement.

[0020] (V) Inner Tube Wall Integrity Principle: To improve the metering accuracy and reduce fluid resistance of ultrasonic flow meters, the inner tube wall of the flow meter should be intact. Uneven structures on the flow meter's flow channel surface due to transducer installation can cause fluid turbulence, significantly impacting the metering accuracy, range ratio, and consistency at low flow rates.

[0021] (VI) Flowmeter Consistency Principle: To reduce manufacturing costs and facilitate manufacturing, standard parts (such as welded and injection-molded parts) combined with excellent manufacturing processes should be adopted to ensure high consistency and reliability of large-diameter ultrasonic gas flowmeters. The high-cost, complex, low-precision, and difficult-to-process casting process should be avoided when manufacturing flowmeter pipe sections. Instead, pre-cast pipe sections formed by stretching or forging should be welded and manufactured. Casting processes result in thicker pipe walls (thin walls are difficult to cast and prone to pinholes), leading to higher costs. Furthermore, the inner diameter of cast pipe sections varies significantly and is difficult to process (due to the common occurrence of necking). This makes large-diameter flowmeter calibration labor-intensive and time-consuming, requiring individual calibration and compensation for each flowmeter base meter. Additionally, the transducer assembly installation process must have high precision and consistency (cast pipe bodies cannot achieve high consistency) and interchangeability of parts. This determines the quality of mass-produced flowmeters, and this level of precision determines the flowmeter's grade and the time and effort saved during calibration.

[0022] (vii) Low pressure loss principle: In order to increase the flow rate and thus increase the range ratio, the flow meter will adopt the method of narrowing the flow meter channel. However, the narrowed channel must meet the pressure loss specified by the flow meter to reduce transmission energy consumption.

[0023] (viii) Pipe Body Sealing Safety Principle: For flow meters with larger diameters, using sealing rings of the same size as the pipe diameter to solve the pipe body sealing problem is difficult to install and poses a risk to the sealing effect. Therefore, use as few sealing rings as possible or use smaller sealing rings to ensure the reliability and durability of the seal.

[0024] Theoretical derivation of the above principle (i):

[0025] 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.

[0026] 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%).

[0027] 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 overall zero drift generated by the ultrasonic flowmeter circuit and transducers, as well as the design value of the water resistance in the flowmeter pipeline). Therefore, for a given 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:

[0028]

[0029] In the above formula, Q3 is the common 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:

[0030] 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.

[0031] Theoretical derivation of principle (ii) above:

[0032] This invention solves this problem using a grid-like partitioned structure, based on the principle of velocity stability in parallel small-diameter pipes. For fluid flow within pipes, 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 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. Velocity disturbances in the flow field 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 here:

[0033] 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., Az = 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:

[0034] 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) in a combined flow channel is smaller than that in the large-diameter straight pipe. This means 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, by using a combined flow channel method, a large flow channel is divided into multiple smaller channels. This not only allows for automatic fluid rectification but also eliminates or reduces the strict requirement of a 10-unit length of straight pipe before and after the flow meter installation, thus improving measurement accuracy.

[0035] 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.

[0036] Several existing technologies for ultrasonic transducer installation and flow channel partitioning in the implementation of ultrasonic flow meters include:

[0037] The ultrasonic gas meter uses an angled transducer installation method. This installation method has a short sound path, few sound channels, and high requirements for the precision of the angled hole machining. For example, the authorized announcement number CN 211696533 U provides a base pipe structure for a large-diameter multi-channel angled through-beam ultrasonic flow meter. The angle between the two transducers in this scheme and the direction of fluid flow in the pipe section is large, so the projection distance is very short, which violates principle (1). 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 (4). The machining angle of the angled hole for installing the transducer is very important. If the deviation is small, the sound wave reception intensity will be greatly reduced for large diameters, so the machining is difficult, which violates principle (6).

[0038] Based on the variability and compressibility of gas volume, to stabilize the fluid state, large-diameter ultrasonic gas meters should have their gas flow pipes rectified. Patent announcements CN 210166007 U and CN 210071019 U both provide a basic pipe structure for an ultrasonic flowmeter. For rectification, a honeycomb gas flow channel is installed only at the inlet section of the gas inlet pipe, failing to achieve rectification across the entire flowmeter pipe section. Particularly, the ultrasonic measurement section lacks zoning, leading to interference between flow velocities in different flow layers and inherent measurement uncertainty, which violates principle (II). Furthermore, the transducer is still installed using an oblique insertion method, violating principle (I).

[0039] Patent application publication number CN 114295167 A discloses a structure for a large-diameter multi-channel ultrasonic gas meter with a layered layout of internally lined flow channels. Compared to the oblique insertion transducer arrangement, this column-mounted transducer structure results in a much smaller angle between the lines connecting two transducers in the fluid flow direction within the pipe section, allowing for a larger spacing between a pair of transducers. However, the column-mounted transducers can only be installed inside the gas meter flange, thus limiting the spacing between pairs of transducers. This design also allows for the arrangement of multiple transducers at different heights, improving measurement accuracy and range ratio. While the flow channel cross-section can be horizontally partitioned according to different heights, because the transducer channels form an angle with the fluid flow direction (obliquely facing each other), vertical partitioning in the flow channel is not possible at regular intervals. For larger diameter flow channels, uncertainties in fluid velocity fluctuations still exist within a single partition. Therefore, the technical solution has not yet achieved the optimal values ​​for principles (1) and (2) and there is still room for improvement; the signal line of the gas meter is led out from the outside of the pipe body through the conduit to the middle of the instrument, which is less safe and more complicated to install, and there is still room for improvement.

[0040] Patent authorization announcement number CN 215726162 U provides a structure for 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: multiple sets of through-beam transducers are arranged at both ends of the flow meter pipe section in the direction of fluid flow. For a given flow meter pipe length, the effective sound path can be fully utilized to improve the range ratio, which meets the requirements of principle (1); the multi-channel design can measure the flow channel space in all directions, which meets the requirements of principles (3) and (4); the structure of dividing the flow channel in the entire space can effectively stabilize the flow state of the fluid, overcome the influence of turbulence, and ensure stable measurement, which meets the requirements of principle (2); the pipe section is welded, which meets the requirements of principles (5) and (6). However, this layout and arrangement of transducers also has drawbacks and shortcomings, because (1) in this technical solution, multiple sets of transducers are arranged on both sides of the pipe, as shown in the appendix to the specification. Figure 2 and 3 As shown, they are located within the annular cavity structure ring 315; (2) as per the instruction manual. Figure 5 As shown, the transducer has a rear protrusion 333 for positioning, so this type of transducer is relatively large; (3) as shown in the instruction manual Figure 1 As shown, the transducer's main lead-out line 56 is led out from the inside of the flanges at both ends of the flowmeter pipe section, etc.

[0041] According to the technical solution provided by the above-mentioned patent, its application is only applicable to flow meters with larger diameters, such as flow meters with a diameter greater than 100mm, i.e., DN100 and above. The reason is that the annular cavity structure ring 315 of this solution occupies a large flow channel cross section, which is not suitable for large-diameter flow meters with smaller diameters, otherwise the pressure loss will be very large. In addition, for large-diameter flow meters, it is difficult to weld the transducer lead wire fixing seat 24 when the signal line is led out from the inside of the flange near the flange, and the instrument box 51 is also large in size, making it difficult to improve its protection level.

[0042] For example, if the above technical solution is applied to a flow meter with a DN100 diameter:

[0043] To improve metering accuracy at low flow rates, i.e., to increase the flow meter's range ratio and obtain a smaller starting flow, manufacturers will neck the flow meter's flow channel. Considering that the necking meets the pressure loss level specified in the standard and reduces pipeline energy consumption, the ratio of the diameter after necking to the diameter before necking is usually greater than 0.8:1, that is, the minimum cross-sectional area ratio of the flow meter pipe must be greater than 0.64. In other words, the ratio of the cross-sectional area of ​​the flow meter after necking to that before necking cannot be less than 0.64.

[0044] So, in the technical solution of patent grant announcement number CN 215726162 U (attached to the specification) Figure 2 and 3 If the smallest transducer currently in use is adopted, i.e., its outer diameter is Ф10mm, and the diameter after the sealing ring needs to be placed on the outside is at least Ф12mm, and the diameter after the protrusion 333 after fixing the transducer is Ф16mm, then the width of the annular cavity structure ring 315 is at least 18mm.

[0045] In a flow meter pipe with a diameter of Ф100mm, assuming that the outer diameter of the annular cavity structure ring 315 maintains a 15mm gap with the pipe wall, then the width of the annular cavity structure ring 315 is 18mm, and the area it occupies is 3.14*(35 2 -17 2 ) = 2939mm 2 The columns supporting the ring structure occupy an area of ​​15*6*5=450mm². 2 The cross-sectional area of ​​the flow meter pipe with a diameter of Ф100mm is 3.14*50. 2 =7850mm 2 After the energy exchanger is installed, the actual flow area of ​​the channel is calculated to be 7850 mm². 2 -2939mm 2 -450 mm 2 =4461mm 2 ;

[0046] The ratio of the area after transducer installation to the area before transducer installation is 4461 mm. 2 / 7850mm 2 =0.568<0.64, therefore, flow meters with a diameter less than 100mm, i.e. less than or equal to DN100, cannot adopt the technical solution of patent authorization announcement number CN 215726162 U.

[0047] In addition, for large-diameter flow meters, such as DN150 water meters, the national standard pipe length is 300mm. According to the above technical solution, the length of the instrument box is about 250mm, the shape is rectangular, and the volume and internal space are large, which makes it difficult to improve the protection level of the instrument box.

[0048] In summary, through technical analysis of several existing metering methods for pipeline gas flow measurement, it is evident that ultrasonic flow measurement is the most reasonable and advanced method in the field of gas metering. A detailed analysis of existing ultrasonic liquid and gas flow meters was conducted, examining factors such as the number of transducers installed, flow channel zoning and rectification, transducer lead-out methods, instrument box structure, and especially the increased pressure loss caused by different transducer placement methods within the flow meter due to flow channel zoning and the space occupied by the transducers in the flow channel. Based on principle (1), to improve the range ratio, installing multi-channel, through-beam ultrasonic transducers within the flow meter pipeline is undoubtedly the best choice. However, further calculations and analysis of the specific applications of existing technologies reveal that it is currently impossible to achieve multi-channel ultrasonic gas flow meters with in-pipe through-beam transducers and flow channel zoning for diameters ranging from DN50 to DN100. Summary of the Invention

[0049] To address the aforementioned unresolved challenges, this paper proposes a large-diameter, multi-channel, zoned, through-beam ultrasonic gas flow meter. By modifying the structure of multiple pairs of transducers arranged in a zoned, through-beam configuration within the pipeline, the proportion of the flow channel cross-section occupied by the transducers is reduced. Furthermore, a series of changes to the signal line lead-out method, instrument box, and its installation structure resolve existing problems. The flow meter simultaneously meets the requirements of the proposed eight principles, achieving the application goals of a full range of large-diameter ultrasonic gas flow meters. The technical solution is as follows: a three-section inner liner is installed in the middle and at both ends of the large-diameter flow meter tube sleeve; the outer inner liner at both ends has a symmetrical structure, containing transducer mounting seats, wiring channels, and wiring conduits; the transducers are embedded in the mounting seats; several mounting seats are independent of each other and connected by wiring channels, which ultimately converge at the wiring conduit; after the signal line wiring is completed, the wiring channels are tightly sealed with covers. The inner liner tube contains longitudinally and transversely intersecting partitions and enclosed conduits. A signal lead-out opening is located in the middle of the conduit, communicating with a positioning groove in the center of the inner liner tube. This positioning groove is fixed and sealed by a positioning cap within the fixing seat in the middle of the tube body sleeve. Two identical outer liner tubes are fixed to the outer ring of the inner liner tube at both ends with a convex-concave structure. Simultaneously, the conduits between them are interlocked, forming a complete signal line channel. The instrument box has a double-layer structure; the outer layer connects to the tube body sleeve, while the inner layer houses and seals the integration circuitry and components. This creates a large-diameter, multi-channel, zoned, through-beam ultrasonic gas flow meter. The signal line, starting from the transducer, is led out through the positioning groove in the middle of the inner liner tube via the conduit and conduit to the instrument box, where it electrically connects to the circuit board.

[0050] This invention relates to a large-diameter, multi-channel, flow-channel, partitioned, through-beam ultrasonic gas flow meter, comprising a pipe sleeve, a fixing seat 1, a positioning cap, a bolt 1, a bolt 2, an inner liner 1, a wiring conduit 1, a fixing seat 2, a wiring groove 1, a cover 1, an inner liner 2, a wiring conduit 2, a transducer, a pressure cap, an instrument box 1, an instrument box 2, and a glass surface. A three-section inner liner is installed in the middle and at both ends of the large-diameter flow meter pipe sleeve. The inner liner 1 at both ends contains a fixing seat 2, a wiring groove 1, and a wiring conduit 1. The transducer is embedded in the fixing seat 2. Several fixing seats 2 are independent of each other and connected by wiring groove 1, which ultimately converge at a single point on the wiring conduit. After the signal wiring is completed, the wiring groove 1 is tightly sealed by the cover 1. The inner liner 2 in the middle contains longitudinally and transversely intersecting partitions 2 and a closed wiring conduit. Second, the middle of the second conduit has a through hole for the signal line, which communicates with the second positioning groove in the middle of the second inner liner tube. The second positioning groove is positioned, fixed, and sealed by the positioning cap in the middle fixing seat of the tube sleeve. The two identical inner liner tubes are fixed to the outer rings at both ends of the middle inner liner tube by positioning head one and positioning groove one. At the same time, the first conduit is embedded in the second conduit to form a complete signal line channel. The instrument box has a double-layer structure, that is, the first instrument box is responsible for the connection with the first fixing seat of the tube sleeve, and the second instrument box is responsible for the placement and sealing of the circuit board and battery. Thus, a large-diameter multi-channel flow channel partitioned through-beam ultrasonic gas flow meter is formed, starting from the transducer, the signal line is led out from the second positioning groove in the middle of the second inner liner tube through the first conduit and the first and second conduits to the second instrument box and electrically connected to the circuit board.

[0051] The transducer is fixed in the fixing base two by embedding; furthermore, the protrusion three fits tightly with the positioning curved surface, and the positioning surface four contacts and positions the positioning surface two; there are multiple fixing bases two.

[0052] The cable tray 1 has one end connected to the fixing base 2 and the other end connected to the cable conduit 1, forming a signal line transmission channel; furthermore, the width of the cable tray 1 is 1.3 to 3 mm.

[0053] In addition, the cover one covers the entire wiring groove one; furthermore, the protrusion one and the notch one are interlocked; the positioning surface three contacts and positions the positioning surface one; the protrusion two is tightly fitted with the wiring groove one; the shape of the cover one is determined by the number of transducers and the wiring groove one.

[0054] The second wiring conduit and the second partition plate are integrated; furthermore, the second partition plate is injection molded, and its width is 1-3mm.

[0055] The inner liner tube 2 is fixed by a positioning cap. Furthermore, the side of the positioning cap has rubber rings 3 and 4 that respectively contact and seal with the inner side of the tube sleeve and the fixing seat 1, wherein rubber ring 3 is below the gasket; rubber ring 5 contacts and seals with the side of the positioning groove 2, and rubber ring 6 contacts and seals with the bottom surface of the positioning groove 2; the bolt 1 fixes the positioning cap by tightening the gasket.

[0056] The fixing tube below the instrument box is fitted on the outside of the fixing seat, and the two are sealed by a rubber ring.

[0057] The instrument box 2 is inside the instrument box 1. The two are fixed by bolt 2 passing through the central hole of the instrument box 2, and the external thread of the bolt is connected to the internal thread of the fixing seat 1. The rubber ring 1 is located below the bottom surface of the inner instrument box and cooperates with the upper part of the fixing seat 1 for sealing.

[0058] The glass surface is located at the upper opening of the instrument box 2, and there is a rubber ring 7 below it; furthermore, the glass surface is fixed by pressing the pressure surface by engaging the internal thread of the pressure cap with the external thread of the instrument box 1.

[0059] The technical solution of this invention can realize a full range of large-diameter, multi-channel, flow-channel, zoned, through-beam ultrasonic gas flow meters. Large-diameter flow meters typically refer to those starting from DN50. Taking a DN50 diameter, four-channel ultrasonic flow meter as an example, a calculation is provided: If a uniform cylindrical transducer with an outer diameter of Ф10mm is still used, then the outer diameter of transducer mounting base two is Ф12mm. Using four channels (i.e., installing four transducers), the area of ​​the four mounting bases two is approximately 452mm². 2 For a DN50 diameter cable tray, the total area of ​​the cable tray plus the area occupied by the partition plate is approximately 232 mm². 2 The total is 684mm 2 .

[0060] Therefore, in a flow meter pipe with a diameter of Ф50mm, the cross-sectional area of ​​the flow meter pipe is 3.14*25. 2 =1962.5mm 2 After the energy exchanger is installed, the actual flow area of ​​the channel is calculated to be 1962.5 mm². 2 -684 mm 2 =1278.5mm 2 ;

[0061] The ratio of fluid throughput after transducer installation to that before transducer installation is 1278.5 mm. 2 / 1962.5mm 2=0.651>0.64 (the ratio of fluid throughput after necking in a conventional flowmeter). Therefore, the technical solution used in implementing this invention can be applied to flowmeters with a diameter of Ф50mm, i.e., a diameter ≥ DN50, solving the problem that the technical solution in patent authorization announcement number CN215726162U cannot be applied to flowmeters with a diameter ≤ DN100.

[0062] Since the width of the inner liner tube 1 is the same as the height of the transducer mounting base 2, and the acoustic wave emitting surface of the transducer is close to the inlet section of the inner liner tube 2, the partition plate 1 inside the inner liner tube 1 has little effect and can be removed to increase the flow area inside the inner liner tube 1. At this time, the ratio of the area after the transducer is installed to that before the transducer is installed is: 1353.5mm2 / 1962.5mm2=0.69>0.64, which is better.

[0063] In summary, this invention utilizes the aforementioned technical solution to separately house multiple transducers in their respective transducer mounting bases. This significantly reduces the area occupied by the mounting base of the multi-channel through-beam transducer within the flow meter's cross-section, thereby enabling a full range of large-diameter gas flow meters to achieve maximum flow rate range ratio while minimizing pressure loss, meeting application requirements. This solves the problem that the technical solution in patent authorization announcement number CN 215726162 U cannot be applied to flow meters with a diameter ≤ DN100. Compared with existing technologies, the technical improvements proposed in this invention represent substantial and significant progress, manifested in the following ways:

[0064] First, since the transducer is installed in the flow channel close to both ends of the flow channel and in the same direction as the fluid flow, according to the theoretical deduction of principle (1), the flow meter has achieved the target of maximizing the range ratio and meets the requirements of principle (1).

[0065] Second, since the small, equal-diameter transducers are installed in opposite directions in separate fixed bases, it is convenient to set up longitudinal and transverse partitions in the inner liner tube, thus meeting the requirements of principle (II).

[0066] Third, the transducers can be installed in a through-beam manner in the flow channel, and the connection between the transducers is consistent with the direction of fluid flow, thus meeting the requirements of principle (iii).

[0067] Fourth, multiple transducers are installed in the flow channel. The DN50 has 4 channels, and larger diameter transducers can be installed with more channels according to the pressure loss requirements, thus meeting the requirements of principle (iv).

[0068] Fifth, since the pipe body sleeve is welded and an inner liner is installed inside the pipe body sleeve, and the inner liner is injection molded, the inner wall of the partitioned small flow channels is smooth, which meets the requirements of principle (5).

[0069] Sixth, the flow meter tube sleeve is welded and the inner lining and its internal structure are injection molded in one piece. This ensures the consistency of the parts and thus guarantees a high degree of consistency in the flow meter's performance indicators, meeting the requirements of principle (six).

[0070] Seventh, calculations show that the transducer installation scheme used in implementing this invention can meet the pressure loss requirements of a flow meter with a diameter of Ф50mm. Therefore, the technical solution of this invention can meet the pressure loss requirements of the entire series of large-diameter flow meters, which is in accordance with principle (VII).

[0071] Eighth, the technical solution adopted in this invention does not use a large-diameter sealing ring between the inner liner and the pipe body sleeve, which conforms to principle (eight).

[0072] Ninth, in the technical solution adopted in this invention, the transducer signal line is led out from the middle of the tube body and electrically connected to the circuit board inside the instrument box, which is different from the signal line of patent authorization announcement number CN 215726162 U, which is led out from the inside of the two flanges respectively. In this way, not only are the signal line outlets and their components reduced.

[0073] Tenth, the instrument box used in the technical solution of this invention has a circular, double-layer structure. Instrument box one can be made of metal or high-strength engineering plastic, better supporting the connection and sealing with the pipe sleeve fixing seat one. Instrument box two is made of plastic material, supporting the placement and sealing of the circuit board and battery. This not only cleverly solves the connection and sealing problem between the instrument box and the pipe sleeve fixing seat one, but also uses a glass surface on instrument box two, which is inexpensive and more durable. From the flowmeter's appearance, especially the instrument box and its connections, no screws are used for fixing, preventing arbitrary disassembly. Attached image description:

[0074] Figure 1 This is a schematic diagram of the appearance of a large-diameter, multi-channel, flow-channel partitioned through-beam ultrasonic gas flow meter.

[0075] Figure 2 This is a cross-sectional view of the transducer wiring, the fixed position of the partition inner liner tube, and the circuit box structure of a large-diameter gas meter.

[0076] Figure 3 A schematic diagram of the transducer mounting base structure for a large-diameter gas flow meter. Figure 1 ;

[0077] Figure 4 A schematic diagram of the transducer mounting base structure for a large-diameter gas flow meter. Figure 2 ;

[0078] Figure 5 This is a schematic diagram of the transducer wiring trough cover structure of a large-diameter gas flow meter;

[0079] Figure 6 This is a schematic diagram of the appearance of a constant diameter transducer for a large-diameter gas flow meter.

[0080] Figure 7 This is a cross-sectional view of the internal structure of the partitioned inner liner of a large-diameter gas flow meter;

[0081] Figure 8 This is a schematic diagram of the installation of the transducer mounting base and the partition inner liner of a large-diameter gas flow meter;

[0082] Figure 9 This is a schematic diagram showing the relationship between the transducer mounting base and the partition liner tube, as well as the relationship between the partition liner tube and the fixing bolts.

[0083] Figure 10 This is a schematic diagram showing the position of the transducer and its mounting base in the flow channel of a large-diameter gas flow meter.

[0084] In the picture:

[0085] 11. Pipe sleeve; 111. Flange A; 112. Flange B; 12. Fixing seat one; 121. Rubber ring one; 122. Rubber ring two; 13. Screw; 14. Positioning cap; 141. Rubber ring three; 142. Rubber ring four; 143. Rubber ring five; 144. Rubber ring six; 15. Gasket; 16. Bolt one;

[0086] 17. Two bolts; 22. One inner liner tube; 220. One positioning surface; 221. Flow guide cap; 222. One cable conduit; 223. One positioning head;

[0087] 224. Cable Tray 1; 225. Notch 1; 226. Positioning Surface 2; 227. Positioning Curved Surface; 228. Screw Hole 1; 229. Mounting Base 2; 230. Partition Plate 1; 23. Cover 1; 231. Protrusion 1; 232. Positioning Surface 3; 233. Protrusion 2; 33. Transducer; 331. Positioning Surface 4; 332. Protrusion 3; 333. Signal Cable; 55. Inner Liner Tube 2; 551 552. Cable routing conduit 2; 553. Through hole 1; 554. Positioning groove 1; 555. Positioning groove 2; 556. Partition plate 2; 67. Instrument box 1; 68. Lead seal ring; 69. Fixing pipe; 70. Instrument box 2; 71. Positioning head 2; 72. Rubber ring 7; 83. Glass surface; 84. Display screen; 855. Circuit board; 866. Battery; 87. Cover; 886. Pressing surface; 887. Through hole 2. Detailed Implementation

[0088] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0089] Example 1:

[0090] This embodiment is a DN80 diameter, 4-channel, 4-zone through-beam ultrasonic gas flow meter.

[0091] As attached Figure 1 , 2 As shown, this embodiment includes a pipe sleeve 11, a fixing seat 12, a positioning cap 14, a bolt 16, a bolt 27, an inner liner 22, a wiring conduit 222, a fixing seat 229, a wiring trough 224, a cover 23, an inner liner 55, a wiring conduit 551, a transducer 33, a pressure cap 88, an instrument box 66, an instrument box 77, and a glass surface 79. A three-section inner liner is installed in the middle and at both ends of the pipe sleeve 11 of the large-diameter flowmeter; the inner liner 22 located at both ends... The unit has a mounting base 229, a cable tray 224, and a cable conduit 222. The transducer 22 is fixed in the mounting base 229 by embedding. Several mounting bases 2 are independent of each other and connected by cable trays 224, which eventually converge at the cable conduit 222. After the signal line wiring is completed, the cable tray 224 will be tightly sealed by the cover 23. The inner liner tube 255 in the middle has longitudinal and transverse partitions 2555 and a closed cable conduit 2551. The signal line 333 is led into the middle of the cable conduit 2. The through hole 552 communicates with the positioning groove 554 in the middle of the inner liner tube 551; the positioning groove 554 is positioned, fixed, and sealed by the positioning cap 14 inside the fixing seat 12 in the middle of the tube sleeve; the two identical inner liner tubes 22 and the outer rings at both ends of the middle inner liner tube 55 are fixed by the positioning head 223 and the positioning groove 553. At the same time, the cable conduit 222 is embedded in the cable conduit 551, and the two are bonded with epoxy resin to form a complete signal line channel; the instrument box has a double-layer structure, that is, the instrument... Meter box 1 66 is responsible for the connection with the fixing seat 12 of the pipe sleeve 11, and meter box 2 77 is responsible for the placement and sealing of the circuit board 81 and the battery 82. Thus, a transducer 33 is formed, and the signal line 333 is led out from the positioning groove 2 554 in the middle of the inner liner tube 2 through the wiring groove 1 224 and the wiring pipe 1 222 and the wiring pipe 2 551 to the meter box 2 77 and the circuit board 81 for electrical connection. This constitutes a four-channel, four-zone flow channel through-beam ultrasonic gas flow meter that is suitable for DN80 diameter.

[0092] As attached Figure 4 , 6 As shown, the transducer 33 is embedded in the fixing base 229, and the two are bonded together with epoxy resin; furthermore, the protrusion 332 is tightly fitted with the positioning curved surface 227, and the positioning surface 4 331 is in contact with the positioning surface 226 for positioning; there are 4 fixing bases 229.

[0093] As attached Figure 3As shown, the cable tray 224 has one end connected to the fixing base 229 and the other end connected to the cable conduit 222, forming a transmission channel for the signal line 333; furthermore, the width of the cable tray 224 is 1.3mm.

[0094] As attached Figure 3 , 5 As shown, the cover 23 covers the entire wiring trough 1; furthermore, the protrusion 231 and the notch 225 are engaged; the positioning surface 232 contacts and positions the positioning surface 220; the protrusion 233 is tightly fitted with the wiring trough 224; the shape of the cover 23 is determined by the number of transducers 33 and the wiring trough 224, and the cover and the wiring trough are bonded together with epoxy resin.

[0095] As attached Figure 7 As shown, the second wiring conduit 551 and the second partition plate 555 are integrated; furthermore, the second partition plate 555 is injection molded and has a width of 1.3mm.

[0096] As attached Figure 2 As shown, the inner liner tube 2 55 is fixed by the positioning cap 14. Furthermore, the positioning cap 14 has rubber rings 3 141 and 4 142 on its side, which respectively contact and seal with the inner side of the tube sleeve 11 and the fixing seat 12. Rubber ring 3 141 is below the gasket 15; rubber ring 5 143 contacts and seals with the side of the positioning groove 2 554, and rubber ring 6 144 contacts and seals with the bottom surface of the positioning groove 2 554; the bolt 16 fixes the positioning cap 14 by pressing the gasket 15.

[0097] As attached Figure 1 , 2 As shown, the fixing tube 662 below the instrument box 66 is fitted onto the outside of the fixing seat 12, and the two are sealed by the rubber ring 122.

[0098] As attached Figure 2 As shown, the instrument box 2 77 is inside the instrument box 1 66. The two are fixed by bolt 2 17 passing through the central hole of the instrument box 2 77, and the external thread of the bolt is connected and engaged with the internal thread of the fixing seat 12. The rubber ring 121 is located below the bottom surface of the instrument box 2 and cooperates with the fixing seat 1 above to seal.

[0099] The glass surface 79 is located at the opening above the instrument box 2 77, and there is a rubber ring 78 below it; furthermore, the glass surface 79 is fixed by the pressure surface 881 pressing it with the internal thread of the pressure cover 88 and the external thread of the instrument box 1 66.

[0100] Instrument box 2 77 has a complete seal: the instrument box 2 is fixed inside the instrument box 1 by bolt 2 and pressure cover; the lower end face of the instrument box 2 is sealed to the fixing seat 1 by extrusion rubber ring 1, and the fixing seat 1 has an annular notch at the position corresponding to the placement of rubber ring 1; the upper end of the instrument box 2 is connected to the outer side of the instrument box 1 by pressure cover threaded connection, and the pressure cover seals the glass between the glass and the instrument box 2 by extrusion glass compression rubber ring 7.

[0101] The inner liner tube one and inner liner tube two, as well as their internal structures, are all made of engineering plastics in a one-time injection molding process, resulting in lower manufacturing costs and higher product consistency.

[0102] Implementing the technical solution of this invention can realize a full range of large-diameter multi-channel flow channel partitioned through-beam ultrasonic gas flow meters. Taking a diameter of DN80 and a four-channel ultrasonic flow meter as an example, a calculation explanation is given below:

[0103] If we still use a cylindrical transducer with an outer diameter of Ф10mm, then the outer diameter of transducer mounting base two will be Ф12mm. For a four-channel system (i.e., installing four transducers), the area of ​​the four mounting bases two will be approximately 452mm². 2 For a DN50 diameter cable tray, the total area of ​​the cable tray plus the area of ​​the partition plate is approximately 424 mm2, totaling 876 mm2.

[0104] In a flow meter pipe with a diameter of Ф80mm, the cross-sectional area of ​​the flow meter pipe is 3.14*402=5024mm2; after installing the transducer, the actual flow area of ​​the flow channel is: 5024mm2-876 mm2=4148mm2.

[0105] The ratio of the fluid throughput after transducer installation to that before transducer installation is: 4148mm² / 5024mm² = 0.826 > 0.64 (the ratio of the fluid throughput after necking in a conventional flowmeter). Therefore, the technical solution used in this invention can meet the requirements of flowmeters with a diameter of DN80, solving the problem that the technical solution in patent authorization announcement number CN 215726162 U cannot be applied to flowmeters with a diameter ≤ DN100.

[0106] The assembly process of the gas flow meter components adopted in this invention is as follows:

[0107] 1. For example Figure 3 , 4 As shown in Figure 6, epoxy resin is applied to the inner side of the fixing base 229. The positioning surface 331 and the protrusion 332 of the transducer 33 are positioned and tightly fitted with the positioning surface 226 and the positioning curved surface 227 on the fixing base 229.

[0108] Signal line 333 extends out from notch 225, passes through cable tray 224, and extends out through cable conduit 222.

[0109] 2. For example Figure 3 , 5 As shown in Figure 8, apply epoxy resin to cover 23, align it with the wiring groove 224, cover and press it firmly.

[0110] 3. For example Figure 7 As shown, insert the inner liner tube 2 55 into the flow channel of the tube sleeve 11, align the positioning groove 2 554 with the inner hole of the fixing seat 12, and insert the positioning cap 14 with the rubber ring installed.

[0111] 4. For example Figure 2 , 8 As shown, the signal line 333 is threaded into the second conduit 551. When the end of the line reaches the first through hole 552, it is pulled out with tweezers, so that the end of the line can pass through the central hole of the positioning cap 14. Epoxy resin is applied to the outside of the first conduit 222, and then it is aligned with the inner hole of the second conduit 551. At the same time, the positioning head 223 and the positioning groove 553 are positioned. Finally, the screw 13 is aligned with the screw hole 228 and tightened to fix it, thus completing the routing and lead-out of the inner liner tube 1, the inner liner tube 2, and the transducer signal line. Only by using the method of aligning the inner liner tube 1 with the inner liner tube 2 inside the tube body sleeve, that is, aligning the first conduit with the second conduit inside the tube body sleeve, can a longer signal line pass through the central hole of the positioning cap.

[0112] 5. For example Figure 2 As shown, a shim 15 is placed on the positioning cap 14, and the positioning cap is pressed and fixed by tightening the bolt 16.

[0113] 6. For example Figure 1 , 2 As shown, place the rubber ring 122 on the outer ring of the mounting base 12, and then fit the mounting tube 662 under the instrument box 166 onto its outer side; place the rubber ring 121 and the instrument box 277, and tighten them with bolt 217.

[0114] 7. For example Figure 1 , 2 As shown, place the circuit board 81 into the instrument box 2 77 and fix it in place, connect the battery 82, connect the signal line 333 to the circuit board electrically, place the rubber ring 78 and the glass surface 79, tighten the cover 88, and apply the lead seal to complete the assembly.

[0115] It should be noted that in the assembly process of this invention, epoxy resin is used for device connection, and all mating parts are tightly fitted. The mating dimensions of the cover and the groove are small, such as the width of the wiring groove 224 being 1.3mm, so the fit is tight. In addition, transducers, cover one, etc. are always subjected to pressure from the outside to the inside in the flow meter pipeline, and are always tightly fitted. Epoxy resin can withstand high temperature, so it is safe and reliable.

[0116] The above examples illustrate the application of the DN80 diameter large-diameter multi-channel flow-path partitioned through-beam ultrasonic gas flow meter of the present invention, but are not limited to the specific embodiments described above; they are also applicable to gas media with different compositions. If the size of the ultrasonic transducer ceramic plate and the sound wave frequency are changed, the present invention is also applicable to the field of liquid metering. Any modifications or variations made based on the content of this invention are within the scope of protection claimed by this invention.

Claims

1. A large-diameter, multi-channel, zoned, through-beam ultrasonic gas flow meter, characterized in that: The system includes a pipe sleeve (11), a fixing seat (12), a positioning cap (14), a bolt (16), a bolt (17), an inner liner (22), a cable conduit (222), a fixing seat (229), a cable tray (224), a cover (23), an inner liner (55), a cable conduit (551), a transducer (33), a pressure cap (88), an instrument box (66), an instrument box (77), and a glass surface (79). A three-section inner liner is installed in the middle and at both ends of the large-diameter flowmeter pipe sleeve (11). The inner liner at both ends... The inner liner tube (22) contains a second mounting base (229), a wiring trough (224), and a wiring conduit (222). The transducer (22) is embedded in the second mounting base (229). Several second mounting bases are independent of each other and connected by the first wiring trough. The first wiring trough (224) eventually converges at the first wiring conduit (222). After the signal line wiring is completed, the first wiring trough (224) will be tightly sealed by the first cover (23). The inner liner tube (55) contains two longitudinally and transversely intersecting partitions (555) and a closed wiring conduit (551). The middle of the wiring conduit... The instrument box has a through hole (552) from which the signal line (333) is led out. It is connected to the positioning groove (554) in the middle of the inner liner tube (551). The positioning groove (554) is positioned, fixed and sealed by the positioning cap (14) in the fixing seat (12) in the middle of the tube sleeve. The two inner liner tubes (22) with the same structure are fixed to the outer rings at both ends of the inner liner tube (55) in the middle by positioning head (223) and positioning groove (553). At the same time, the cable tube (222) is embedded in the cable tube (551) to form a complete signal line channel. The instrument box has a double-layer structure. That is, the instrument box one (66) is responsible for the connection with the pipe sleeve (11) fixing seat one (12), and the instrument box two (77) is responsible for the placement and sealing of the circuit board (81) and battery (82); thus, a transducer (33) is formed, which leads the signal line (333) through the wiring groove one (224) and wiring pipe one (222) and wiring pipe two (551) from the positioning groove two (554) in the middle of the inner liner pipe two to the instrument box two (77) and the circuit board (81) for electrical connection, thus forming a through-beam ultrasonic gas flow meter that is adapted to four channels and four flow channels.

2. The large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that: The transducer (33) is embedded in the fixing seat two (229); further, the protrusion three (332) is tightly fitted with the positioning surface (227), and the positioning surface four (331) is in contact with the positioning surface two (226) for positioning; there are multiple fixing seats two (229).

3. A large-diameter, multi-channel, zoned, through-beam ultrasonic gas flow meter according to claim 1, characterized in that... The first wiring trough (224) is connected at one end to the second fixing base (229) and at the other end to the first wiring tube (222), forming a transmission channel for the signal line (333); further, the width of the first wiring trough (224) is 1 to 3 mm.

4. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that: The cover (23) covers the entire wiring groove (224); furthermore, the protrusion (231) and the notch (225) are engaged; the positioning surface (232) contacts and positions the positioning surface (220); the protrusion (233) is tightly fitted with the wiring groove (224).

5. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that: The second wiring tube (551) and the second partition plate (555) are integrated; the second partition plate (555) is injection molded and its width is 1-3mm.

6. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that: The inner liner tube 2 (55) is fixed by the positioning cap (14). Furthermore, the positioning cap (14) has rubber ring 3 (141) and rubber ring 4 (142) on its side, which respectively contact and seal with the inner side of the tube sleeve (11) and the fixing seat 1 (12). Among them, rubber ring 3 (141) is below the gasket (15); rubber ring 5 (143) contacts and seals with the side of the positioning groove 2 (554), and rubber ring 6 (144) contacts and seals with the bottom surface of the positioning groove 2 (554); the bolt 1 (16) fixes the positioning cap (14) by pressing the gasket (15).

7. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that... The fixing tube (662) below the instrument box (66) is fitted on the outside of the fixing seat (12), and is sealed by the rubber ring (122).

8. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that... The instrument box 2 (77) is inside the instrument box 1 (66). The two are fixed by bolt 2 (17) passing through the central hole of the instrument box 2 (77) and its external thread connecting with the internal thread of the fixing seat 1 (12). The rubber ring 1 (121) is located below the bottom surface of the instrument box 2 and cooperates with the fixing seat 1 above for sealing.

9. A large-diameter multi-channel flow-channel zoned through-beam ultrasonic gas flow meter according to claim 1, characterized in that: The glass surface (79) is located at the opening above the instrument box 2 (77), and there is a rubber ring 7 (78) below it; furthermore, the glass surface (79) is pressed and fixed by the pressure surface (881) through the internal thread of the pressure cover (88) and the external thread of the instrument box 1 (66).

Images