Large-diameter ultrasonic flowmeter with transducer fixed by flange and continuous sonic path distance

Abstract

The invention belongs to the technical field of flow metering equipment, particularly relates to a large-diameter ultrasonic flowmeter with a transducer fixed by a flange and a continuous sonic path distance, and aims to solve the problem that the large-range-ratio application of an ultra-large-diameter ultrasonic flowmeter cannot be realized in the prior art. A plurality of sections of lining pipes are arranged in a sleeve of a pipe body in a butt joint mode, a plurality of supports are arranged on the inner sides of an inlet and an outlet of each lining pipe in the mode of being perpendicular to the axis, transducers are embedded in the supports respectively, the transducers corresponding to each other in a straight line on the supports parallel to the section of the pipe body are paired in pairs, and therefore the different lining pipes in the same partition are arranged in the same partition. A plurality of groups of sound channel continuous measuring channels formed by two transducers form a straight line, the supports positioned at two ends of the pipe body sleeve are internally fixed through flanges, and transducer signal lines pass through inner holes of the supports and are connected into an instrument box through internal channels of the flanges and the outer side of the pipe body sleeve. Therefore, the large-caliber ultrasonic flowmeter with the sound path distance continuing and the measuring range ratio maximization is achieved.

Description

Technical Field

[0001] This invention belongs to the technical field of flow metering equipment, and specifically relates to a flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous acoustic 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 metering of water, heat, and gas supply for both industrial and residential use.

[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. Currently, the most widely used all-electronic flow metering devices worldwide are electromagnetic flow meters and the rising star, ultrasonic flow meters.

[0004] Ultrasonic flow meters have emerged alongside technological breakthroughs in their time-difference timing chips (from 2012 to 2017, international companies such as AMS, D-FLOW, and TI successively launched relatively advanced time-difference timing chips, and currently, their resolution has reached 5-10 ps, ​​fully meeting the needs of fluid metering applications). In contrast to electromagnetic flow meters, ultrasonic flow meters sample using time-difference digital signals (electromagnetic flow meters sample using analog signals). Taking ultrasonic water meters as an example, they have outstanding technical advantages: smaller starting flow rate (e.g., they can measure liquids with a flow velocity of 0.5 mm / s or higher, while electromagnetic flow meters are usually limited to 3 mm / s), wider range ratio (electromagnetic flow meters have a relatively narrow range ratio), the ability to actively measure the process time difference with sound waves, convert it into fluid velocity and temperature, and simultaneously compensate for the volume change being measured (for which electromagnetic flow meters require the installation of a thermometer), larger diameter multi-channel measurement with higher accuracy and safety (while electromagnetic flow meters only have a pair of coils and corresponding electrodes, and are rendered unusable if they malfunction), the ability to measure various low-viscosity liquids (while electromagnetic flow meters cannot measure low-conductivity liquids, such as pure water), and the ability to measure / meter gases such as fuel gas (electromagnetic flow meters cannot measure gas flow).

[0005] In the field of gas metering, devices that measure gas using all-electronic methods include thermal mass flow meters, vortex flow meters, and ultrasonic flow meters.

[0006] Thermal mass flow meters operate on the linear relationship between flow velocity, temperature, and resistance. Their key advantages include the ability to directly measure and quantify the mass flow rate of a single gas component, good compatibility with different pipe diameters, and low pressure loss. However, based on the principle of sampling from a single point, they have fatal flaws: 1) For large-diameter pipes with wide variations in gas velocity, setting only one or a few measurement points results in limited accuracy; 2) When encountering water-containing gases, the measurement will be inaccurate, rendering it impossible to measure; 3) They can only measure the flow rate of a single gas component, not multiple components, especially those with varying compositions. Therefore, the application and promotion of this method is challenging in complex operating conditions.

[0007] Vortex flow meters, based on their principle, have the advantage that the volumetric flow rate they measure is unaffected by parameters such as the 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's operating 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.

[0008] Ultrasonic flow meters are velocity-type flow meters that use a time-of-flight measurement principle. 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.

[0009] 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 in order to calculate the fluid volume in a wide range and with high accuracy: (1) Multiple pairs of transducers need to be laid out and installed in the pipe of the flow meter. 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 to stabilize the flow velocity in the flow channel, that is, to stabilize the fluid into a non-pulsating flow. Such sampling is more accurate and helps to greatly improve the measurement accuracy; (3) Since the length of the flow meter is a fixed value, the limited pipe length of the flow meter should be used to install the paired transducers at both ends of the fluid inlet and outlet of the pipe as much as possible. In this way, the range of the columnar sampling volume obtained is large, and the range ratio can be maximized. Obviously, the higher the measurement accuracy and the larger the range ratio, the better the measurement performance of the flow meter.

[0010] An ultrasonic flow meter consists of four main parts: a time-difference totalizer circuit, a transducer, a transducer mounting method, and a flow channel rectification structure. The performance of the time-difference totalizer circuit determines the minimum measurable flow rate or resolution, while the overall architecture of the transducer determines the comprehensive performance and quality of the ultrasonic flow meter, including the stability of the measured fluid, signal strength, range ratio, and production cost. Taking an ultrasonic water meter as an example, especially under the constraints of the new national standard R1000 range ratio standard, the optimal solution for an ultrasonic flow meter should follow these principles:

[0011] (I) The Principle of Maximizing the Range Ratio: To ensure that ultrasonic flow meters have a large measurement range (range ratio) while meeting specified accuracy requirements, especially for large-diameter flow 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 flow meter. For example, a manufacturing plant's water consumption during daytime industrial production is 500 times that 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 (negative accuracy value, such as with mechanical meters), which will inevitably cause measurement losses for the water supplier. Therefore, to ensure that ultrasonic flow meters have a large range ratio and achieve fair trade settlement, the projected distance of the line connecting a pair of transducers in the main pipe of the ultrasonic flow meter in the direction of water flow should be maximized to obtain a larger range ratio and a smaller starting flow. This principle determines the most important specification of ultrasonic flow meters.

[0012] (II) Through-beam Multi-channel Zoned Flow Stabilization and Anti-turbulence Interference Principle: Large-diameter flow meters are relatively large. To reduce signal attenuation and ensure signal reception strength, through-beam installation should be selected for the transducers. Furthermore, fluid flow velocities vary at different locations within the pipe, objectively requiring multiple transducers to measure and obtain reliable average flow velocities. Ensuring fluid flow stability guarantees measurement accuracy. To prevent significant instability caused by fluid turbulence, measures must be taken to minimize turbulence and ensure that each selected fluid stream is representative, allowing for more accurate sampling by a pair of transducers and improved measurement accuracy. Additionally, a generally accepted standard for flow meter 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 flow meter. This requirement is essential, especially for large-diameter flow meters. 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 fluid flows into the flow meter from the bends, the 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 flow meter's piping can be divided into zones to create a stable laminar flow, the requirement for straight pipe sections before and after the flow meter will be eliminated, providing strong support for the flow meter's application in various complex situations.

[0013] (III) 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.

[0014] (iv) Consistency Principle in Flowmeter Manufacturing: 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 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, which in turn determines the flowmeter's grade and the time and effort saved during calibration.

[0015] (V) Low pressure loss principle: When a pair of transducers are installed at an angle, the sound path is very short. In order to improve the flow meter's range ratio, the starting velocity must be increased, i.e., the flow meter channel must be necked. However, necking will greatly increase pipeline pressure loss and energy consumption. Therefore, the channel necking must meet the pressure loss value specified by the flow meter. Thus, the range ratio improvement achieved by this necking method is very limited. In addition, if the transducer is installed inside the pipeline, the smaller the volume of the transducer and its installation method, the better, in order to reduce fluid resistance and fluid interference to the transducer.

[0016] (vi) 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.

[0017] To further illustrate this point, the following is a theoretical derivation of the above principles (i) and (ii):

[0018] Theoretical derivation of the above principle (i):

[0019] 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.

[0020] 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%).

[0021] 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 also decreases proportionally (i.e., the corresponding minimum flow velocity V1 decreases). 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 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:

[0022]

[0023] 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:

[0024] 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.

[0025] Theoretical derivation of principle (ii) above:

[0026] 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:

[0027] 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:

[0028] 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.

[0029] 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 column for velocity.

[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) Based on current practical applications, for example, when f = 2MHz, a transducer spacing of 300mm can basically meet the sound wave reception requirements in water; however, for gases, such as air (or fuel gas), when f = 0.2MHz, with the same driving voltage and sound wave intensity, a transducer spacing of 100mm will result in a sound intensity received at the receiving end that is reduced to 1 / 10 or less of the intensity at a frequency of 2MHz and a transducer spacing of 300mm; therefore, especially for gases, if the transducer spacing is 400mm, even if the excitation voltage of a pair of transmitting transducers is increased to 18V, it is usually difficult to meet the sound intensity / amplitude requirements for signal reception. For example, for a DN500 gas meter, if the length of its flow meter is 500mm, according to I = I o e -2αx As the distance of ultrasonic waves increases in the direction of propagation, their exponential attenuation makes it virtually impossible to achieve metering by installing a pair of transducers along the entire length of the pipe.

[0034] The above demonstrates that achieving ultrasonic time-of-flight metering is difficult regardless of whether a 2MHz ultrasonic transducer with a 500mm spacing or a 0.2MHz ultrasonic transducer with a 500mm spacing is used in water. This explains why there is currently no application or technical data available for ultrasonic gas meters with a diameter of DN300 or larger.

[0035] 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 inside the annular cavity structure ring 315, and the volume of the structure ring is relatively large. This method is only suitable for situations where the flow meter has a large diameter; (2) As shown in 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 main lead 56 of the transducer is led out from the inside of the flange at both ends of the flow meter pipe section. It has a mounting base and is relatively complicated to process. (4) For ultra-large diameter flow meters, such as liquid DN1200 and gas DN300, the method of placing a pair of ultrasonic transducers at both ends of the pipe as much as possible cannot meet the requirements of signal triggering and metering due to the large attenuation of sound waves.

[0036] In summary, given the attenuation of acoustic energy when ultrasound propagates in liquids and gases, the ultrasonic time-of-flight measurement principle must be adopted to fully utilize the specified flowmeter tube length and meet the conditions of principle (I) mentioned above, i.e., to maximize the range ratio and realize the application of large-diameter (e.g., in liquids, using a 2MHz transducer to achieve DN800 or larger diameter) ultrasonic flowmeters. This is a major challenge facing the ultrasonic flow metering industry. According to current available data, it is not yet possible to achieve this, and the problem urgently needs to be solved.

[0037] Therefore, the technical goal of this case is to overcome the shortcomings of the existing technology and innovate a new structure for a large-diameter ultrasonic flow meter that meets the requirements of high accuracy and large range ratio in flow meter measurement. Summary of the Invention

[0038] To address the aforementioned industry challenges, this paper proposes a large-diameter ultrasonic flow meter with flange-fixed transducers and continuous sound path. By utilizing the continuous sound path between multiple pairs of ultrasonic transducers, the total effective sound path is extended to approach the specified flow meter tube length. This not only enables the measurement of large-diameter or ultra-large-diameter liquids and gases but also maximizes the flow meter's range ratio, solving a major industry problem in measurement. The technical solution is as follows:

[0039] Multiple inner liner sections are installed inside the pipe casing. Multiple supports are arranged perpendicularly to the axis on the inlet and outlet sides of each inner liner. Transducers are embedded within these supports, with transducers paired in pairs on supports parallel to the pipe cross-section. This creates a straight line connecting multiple sound channels within different inner liner sections of the same zone. The supports at both ends of the pipe casing are fixed internally by flanges, and the transducer signal lines pass through the inner holes of the supports, through the internal channels of the flanges, and through the outside of the pipe casing to the instrument box. This achieves a large-diameter ultrasonic flow meter with continuous sound path and maximized range ratio.

[0040] This invention relates to a flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, characterized by: a flange 1; a flange 2; a pipe sleeve; a fixing seat 1; a boss 1; a fixing seat 2; an inner liner 1; a partition 1; an inner liner 2; a partition 2; a fixing head; a bracket 1; a transducer; a signal line; a bolt 1; a bolt 2; a bracket 2; a bracket 3; a bracket 4; an instrument box 1; a fixing pipe 1; and a protective shell. The inner liner 1 and inner liner 2 are joined together inside the pipe sleeve. Multiple brackets 2 and multiple brackets 4 are respectively arranged perpendicular to the axis on the inner side of the inlet and outlet of the inner liner 1. Multiple brackets 2 are arranged on the inner side of the outlet of the inner liner 2. Two brackets 2 and four are arranged on the inner side of the outlet of the inner liner 2. The ends are welded and fixed to the inner side of the inner liner and one side of the partition plate, respectively; bracket one and bracket three are fixed to bracket two and bracket four respectively through column and hole fit; the transducers are embedded and placed in bracket one and bracket three respectively, and the transducers corresponding to each other on bracket one and bracket three are paired up in pairs, so that in the same partition in inner liner one and inner liner two, the two sets of sound channels formed by the two pairs of transducers form a straight line for continuous measurement; one end of bracket one is fixed through the inner side of the flange, and the transducer signal line is connected to the instrument box through the inner hole of the bracket, through the internal channel of the flange and the outside of the pipe sleeve, thereby realizing a large-diameter ultrasonic flow meter with continuous sound path and maximized range ratio.

[0041] The transducer is tightly embedded in the curved surface of the bracket one, with the protrusion tightly fitted to the curved surface two, the plane four coinciding with the positioning surface one, and the signal line passing through the hole six; for the bracket three, two transducers are tightly embedded in the curved surface four from both ends of the column five, with the curved surfaces tightly fitted, the plane four coinciding with the positioning surface two, and the signal line passing through the hole eight.

[0042] The bracket 1 is tightly fitted with hole 7 of bracket 2 through column 1, and column 2 is tightly fitted with curved surface 3. The lower plane of the straight rod of bracket 1 passes through notch 1 and coincides with the upper plane of the straight rod of bracket 2. Plane 3 coincides with convex edge 1. Furthermore, plane 2 of bracket 1 is embedded in inner liner tube 3.

[0043] The bracket three is tightly fitted with the hole nine of the bracket four through the column four, and the column five is tightly fitted with the curved surface five. The lower plane of the straight rod of the bracket three passes through the notch two and coincides with the upper plane of the straight rod of the bracket four. In addition, the plane seven of the bracket three is embedded in the inner liner tube four.

[0044] The bracket 1 is positioned and fixed by a fixing head installed in hole 1 in flange 1 and flange 2; further, positioning surface 2 coincides with positioning platform in hole 1, rubber ring 4 contacts and seals with inner liner tube 3 and plane 2, rubber ring 3 contacts and seals with inner wall of hole 1, and rubber ring 2 contacts and seals with inner wall of hole 1 and gasket; further, bolt 1 presses the fixing head with gasket, thereby fixing inner liner tube 3; hole 1 has hole 4, which is located on the upper side of bolt 1, and bolt 2 is located at the upper end of hole 1.

[0045] The bracket three is positioned and fixed by a fixing head placed in the hole of the fixing seat two; further, the positioning surface two coincides with the positioning platform in the hole, the rubber ring four contacts and seals with the inner liner tube three and the plane seven, the rubber ring three contacts and seals with the inner wall of the hole, and the rubber ring two contacts and seals with the inner wall of the hole and the gasket; further, the bolt one presses the fixing head with the gasket, thereby fixing the inner liner tube three.

[0046] The partition plate 1 and partition plate 2 are located inside the metal inner liner tube 1 and inner liner tube 2, respectively. They are arranged in a grid pattern at certain intervals in the horizontal and vertical directions, and are respectively welded to the inner walls of the metal inner liner tube 1 and inner liner tube 2. The inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 can be in multiple sets as needed. Furthermore, the inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 can be made of the same material and are integrated into a single structure.

[0047] The boss is connected to the inside of flange one or flange two and the outside of the pipe sleeve. Furthermore, one side of the boss has hole four and the upper side has hole three. The inner side of the protective shell coincides with the upper side of the boss and is fixed by screws and hole three.

[0048] By implementing the above technical solutions, the range ratio of large-diameter (usually referring to diameters from DN50 to DN250) or ultra-large-diameter (diameter ≥ DN300) flow meters can be substantially improved, with significant results. This leads to a leap forward in the practical application of large-diameter or ultra-large-diameter flow meters, as detailed below:

[0049] First, maximize the range ratio by fully utilizing the given flowmeter tube length: Based on the effective sound intensity (amplitude) that a pair of transducers can receive, determine the maximum safe distance Li for signal reception between the pair of transducers. Within the tube casing under the given flowmeter tube length condition, install one or more sections of inner lining tube. Arrange multiple sets of supports and transducers on the beginning and end cross-sections of different inner lining tubes. Thus, within a section of the flowmeter cross-section, several pairs of transducers connected end-to-end form a straight line, creating a continuous sound path. This is equivalent to arbitrarily extending the distance between a pair of transducers to the required length of the flowmeter tube. It can be seen that the flow meter has achieved the maximum range ratio.

[0050] Secondly, achieving through-beam multi-channel and zoned flow stabilization: Each pair of transducers is installed through-beam and aligned with the fluid flow direction. According to R = β·L·cos(α), R = β·L, with the effective value at its maximum. Using partitions, zoned flow stabilization is achieved within the flowmeter's tube casing, with several pairs of transducers placed in each zone. Due to the zone isolation, a stable laminar flow is formed within the small partitioned cavities. Therefore, the flowmeter can resist the flow deviation impact of the preceding bend, accurately measure velocity changes within several zones, and ultimately obtain the fitted average velocity to calculate the accurate volumetric flow rate.

[0051] Third, the inner tube wall remains intact: Unlike the transducer's oblique insertion, the ultrasonic transducer of this invention is installed inside the flow channel without mounting holes, so the flow channel is smooth.

[0052] Fourth, the flow meters have high consistency in mass production: the flow meter tube body is welded and formed, and the parts are injection molded or processed according to precision standards; the installation of the transducer and the positioning and fixing of the bracket are standardized. Therefore, the flow meters produced in batches have high consistency, simplified flow calibration, and easy replacement and interchangeability of parts during maintenance.

[0053] Fifth, low pressure loss of the flow meter: For the inclined insertion ultrasonic transducer installation method, due to its short sound path, in order to obtain a relatively high range ratio, the method of necking is usually chosen to increase the flow velocity. The common method of necking is to reduce the diameter by 20%. That is to say, for a DN100 flow meter, the flow area after necking is 64% of the original, resulting in a large increase in pressure loss. Because the sound path of this invention is extended, the range ratio is large, and anti-interference partitions are set, the flow meter does not need to be necked. Moreover, the cross-sectional area of ​​the transducer and the support is very small, so the actual pressure loss of the flow meter is close to that of a straight pipe, which is very low.

[0054] Sixth, the tube body has high sealing safety: the transducer and the bracket are tightly connected and coated with epoxy resin; the transducer signal line is sent out through the bracket hole channel, and the bracket is sealed and fixed by the fixing head, using a small sealing ring, which is safe and reliable.

[0055] Seventh, flange mounting brackets are cleverly used on both sides of the flowmeter tube sleeve. This not only eliminates the need for a mounting head but also, because the transducer is placed below the flange, the transducer installation meets the requirements of principle one, maximizing the sound path. Eighth, engineering plastic brackets one and three for fixing the transducer are cleverly placed on metal brackets two and four, respectively. In addition to the ease of welding and fixing the metal brackets, their high strength helps brackets one and three resist water hammer or high-velocity impacts. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the appearance of a large-diameter ultrasonic flow meter with a flange-fixed transducer and continuous sound path.

[0057] Figure 2 This is a cross-sectional view of a large-diameter ultrasonic flow meter with a flange-fixed transducer and continuous sound path.

[0058] Figure 3 This is a side view of a large-diameter ultrasonic flow meter with a flange-fixed transducer and continuous sound path.

[0059] Figure 4 This is a schematic diagram showing the welding position between the metal support 2 and the inner liner tube 1;

[0060] Figure 5 This is a schematic diagram of the transducer bracket and the transducer assembly.

[0061] Figure 6 This is a schematic diagram of the transducer bracket 1 and the assembly of the transducer and the metal bracket 2.

[0062] Figure 7 This is a cross-sectional view of a large-diameter ultrasonic flow meter flange with an internally fixed transducer support.

[0063] Figure 8This is a cross-sectional view of the installation structure of a flange-fixed transducer bracket;

[0064] Figure 9 This is a schematic diagram of the assembly of transducer bracket three and dual transducers with metal bracket four;

[0065] Figure 10 This is a cross-sectional view of the transducer bracket three and the dual transducers assembled with the metal bracket four.

[0066] Figure 11 This is a cross-sectional view of the transducer support three and the transducer and metal support four assembled in the middle of the tube sleeve.

[0067] Figure 12 This is a schematic diagram of the connection between the four inner liner tubes and the position of the transducer support.

[0068] Figure 13 This is a schematic diagram of the signal line routing for a large-diameter ultrasonic flow meter with a flange-fixed transducer and continuous sound path.

[0069] Figure 14 This is a schematic diagram of the instrument box structure and signal line connections;

[0070] Figure 15 This is a schematic diagram of the fixed head structure.

[0071] In the picture:

[0072] 11. Flange A; 12. Flange B; 1112. Hole 1; 13. Pipe sleeve; 14. Fixing seat 1; 141. Hole 2; 142. Rubber ring 1; 15. Boss 1; 151. Hole 3; 152. Hole 4; 16. Fixing seat 2; 21. Inner liner tube 1; 211. Partition plate 1; 22. Inner liner tube 2; 221. Partition plate 2; 23. Inner liner tube 3; 231. Hole 5; 232. Plane 1; 24. Inner liner 30. Pipe 4; 30. Fixing head; 301. Rubber ring 2; 302. Rubber ring 3; 303. Rubber ring 4; 304. Positioning surface 2; 31. Bracket 1; 311. Plane 2; 312. Column 1; 313. Column 2; 314. Flow guide cap; 315. Curved surface 1; 316. Positioning surface 1; 317. Hole 6; 318. Curved surface 2; 319. Plane 3; 33. Transducer; 331. Protrusion; 332. Plane 4; 333. Plane 5; 334. Ceramic plate; 335. Terminal block; 34. Signal line; 35. Washer; 36. Bolt 1; 37. Bolt 2; 41. Bracket 2; 411. Hole 7; 412. Post 3; 413. Protrusion 1; 414. Notch 1; 415. Plane 6; 416. Curved surface 3; 32. Bracket 3; 321. Plane 7; 322. Post 4; 323. Post 5; 325. Curved surface 4; 326. Positioning surface 2; 327. Hole 8; 328. Curved surface 2; 42. Bracket 4; 421. Hole 9; 422. Column 6; 424. Notch 2; 425. Flat surface 7; 426. Curved surface 5; 51. Instrument box 1; 511. Fixing tube 1; 512. Positioning protrusion; 52. Cover; 53. Glass surface; 531. Rubber ring 5; 54. Circuit board; 55. Battery; 56. Instrument box 2; 57. Bolt 3; 61. Protective shell; 62. Screw. Detailed Implementation

[0073] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0074] Example 1:

[0075] This embodiment is a flange-fixed transducer, sound path connection, DN300 large-diameter ultrasonic water meter.

[0076] As attached Figure 1 , 2As shown, this embodiment includes flange 11; flange 2 12; hole 1112; pipe sleeve 13; fixing seat 14; boss 15; fixing seat 2 16; inner liner 21; partition 1 211; inner liner 2 22; partition 2 221; fixing head 30; bracket 1 31; transducer 33; signal line 34; bolt 1 36; bolt 2 37; bracket 2 41; bracket 3 32; bracket 42; instrument box 1 51; fixing pipe 1 511; and protective shell 61. Inner liner 1 21 and inner liner 2 22 are connected and installed inside the pipe sleeve 13. Multiple brackets 2 41 and multiple brackets 42 are arranged perpendicularly to the axis on the inner side of the inlet and outlet of inner liner 1 21, and multiple brackets 2 42 are arranged on the inner side of the outlet of inner liner 2 22. 41; The two ends of brackets two and four are welded and fixed to the inner side of the inner liner tube and one side of the partition plate, respectively; brackets one 31 and bracket three 32 are fixed to brackets two 41 and bracket four 42 respectively through column and hole fit; the transducers 33 are embedded and placed in brackets one 31 and bracket three 32 respectively, and the transducers corresponding to each other on brackets one and three are paired up in pairs, so that in the same partition in inner liner tube one and inner liner tube two, the two sets of sound channels formed by the two pairs of transducers form a straight line for continuous measurement; one end of bracket one is fixed through the inner side of the flange, and the signal line 34 of the transducer is connected to the instrument box 51 through the inner hole of the bracket, through the inner channel of the flange and the outer side of the pipe sleeve, thereby realizing a large-diameter ultrasonic flow meter with continuous sound path and maximized range ratio.

[0077] As attached Figure 5 , 9 As shown in Figure 10, the transducer 33 is tightly embedded in the curved surface 315 of the bracket 31, wherein the protrusion 331 is tightly fitted with the curved surface 318, the plane 332 coincides with the positioning surface 316, and the signal line 34 passes through the hole 317; for the bracket 32, the two transducers are tightly embedded in the curved surface 325 from both ends of the column 323, and the curved surfaces are tightly fitted, the plane 332 coincides with the positioning surface 326, and the signal line 34 passes through the hole 327.

[0078] As attached Figure 6 , 4 As shown, the bracket 31 is tightly fitted with the hole 411 of the bracket 41 via the column 312, and the column 313 is tightly fitted with the curved surface 416. The lower plane of the straight rod of the bracket passes through the notch 414 and coincides with the upper plane of the straight rod of the bracket 41. The plane 319 coincides with the protrusion 413. Furthermore, the plane 311 of the bracket 31 is embedded in the inner liner tube 23.

[0079] As attached Figure 9As shown, the bracket 32 ​​is tightly fitted with the hole 9 421 of the bracket 42 via the column 4 322, and the column 5 323 is tightly fitted with the curved surface 5 426. The lower plane of the straight rod of the bracket 3 passes through the notch 2 424 and coincides with the upper plane of the straight rod of the bracket 4. In addition, the plane 7 321 of the bracket 32 ​​is embedded in the inner liner tube 4.

[0080] As attached Figure 8 As shown, the bracket 31 is positioned and fixed by the fixing head 30 installed in the hole 1112 in the flange 11 / flange 2 12; further, the positioning surface 2 304 coincides with the positioning platform in the hole 1112, the rubber ring 4 303 contacts and seals with the inner liner tube 3 23 and the plane 2 311, the rubber ring 3 302 contacts and seals with the inner wall of the hole 1112, and the rubber ring 2 301 contacts and seals with the inner wall of the hole 1112 and the gasket 35; further, the bolt 36 presses the fixing head 30 with the gasket 35, thereby fixing the inner liner tube 3 23; the hole 1112 has a hole 4 152, which is located on the upper side of the bolt 36, and the bolt 2 37 is located at the upper end of the hole 1112.

[0081] As attached Figure 11 As shown, the bracket 32 ​​is positioned and fixed by the fixing head 30 placed in the hole of the fixing seat 2 16; further, the positioning surface 2 304 coincides with the positioning platform in the hole, the rubber ring 4 303 contacts and seals with the inner liner tube 3 23 and the plane 7 321, the rubber ring 3 302 contacts and seals with the inner wall of the hole, and the rubber ring 2 301 contacts and seals with the inner wall of the hole and the gasket 35; further, the bolt 1 36 presses the fixing head 30 with the gasket 35, thereby fixing the inner liner tube 3 23.

[0082] As attached Figure 12 , 4 As shown, partition plate 1 211 and partition plate 221 are located inside the metal inner liner tube 1 21 and inner liner tube 22, respectively. They are arranged in a grid pattern at certain intervals in the horizontal and vertical directions, and are respectively welded to the inner walls of the metal inner liner tube 1 21 and inner liner tube 22. There can be multiple sets of inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 as needed. Furthermore, inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 can be made of the same material and are integrated into a single structure.

[0083] As attached Figure 13 As shown, the boss 15 is connected to the inner side of flange 11 or flange 2 12 and the outer side of pipe sleeve 13. Furthermore, one side of the boss has hole 4 152 and the upper side has hole 3 151. The inner side of the protective shell 61 coincides with the upper side of the boss 15 and is fixed by screw 62 and hole 3 151.

[0084] As attached Figure 14As shown, the fixing tube 511 below the instrument box 51 is fitted onto the outside of the fixing seat 14, and the two are sealed by a rubber ring 142.

[0085] The instrument box 2 56 is inside the instrument box 1 51. The two are fixed by bolt 3 57 passing through the central hole of the instrument box 2 56, and the external thread of the bolt is connected and engaged with the internal thread of the fixing seat 14.

[0086] The glass surface 53 is located at the opening above the instrument box 2 56, and there is a rubber ring 531 below it; furthermore, the glass surface 79 is pressed and fixed by the internal thread of the pressure cover 52 engaging with the external thread of the instrument box 1 51.

[0087] The sound path continuity in this embodiment is implemented as follows:

[0088] The standard specifies that the pipe length of a DN300 water meter is 500mm. Two inner lining pipes are installed inside the water meter pipe casing. Multiple sets of supports and transducers are arranged on the first and last cross-sections of the inner lining pipe. Thus, within a section of the flowmeter cross-section, several pairs of transducers are connected end-to-end to form a straight line, creating a continuous sound path. This effectively extends the distance between a pair of transducers to nearly the length of the water meter pipe. It can be seen that the water meter has achieved the maximum range ratio.

[0089] As attached Figure 12 As shown, in this embodiment, a 2MHz transducer with an outer diameter of 10mm is used. The effective distance for signal reception between a pair of transducers is 250mm. Therefore, it is reasonable to divide the DN300 water meter pipe, which is 500mm long according to the standard, into two ends for measurement. In addition, the circuit can be divided into two types: 1) Single time difference circuit: Since the time difference measurement time is very short (within 1 millisecond), assuming that the change in water flow velocity during the measurement period is negligible, the time difference of AB segment and BC segment can be measured in sequence, and then added together to obtain the total time difference, so as to obtain the average flow velocity and flow rate (the sound speed in water at room temperature is 1500 m / s, and the water flow velocity is a few m / s); 2) Dual time difference circuit: The microcontroller manages two time difference circuits, that is, the time difference of AB segment and BC segment are calculated simultaneously, and then the results are added together to obtain the average flow velocity and flow rate.

[0090] The component assembly process of the technical solution adopted in this embodiment is as follows:

[0091] 1. As attached Figure 12 , 4 As shown, partition plate 1 211 and partition plate 221 are welded to the inner sides of metal inner liner tube 1 21 and inner liner tube 22, respectively; bracket 2 41 and bracket 42 are welded to the corresponding positions of metal inner liner tube 1 21 and inner liner tube 22, respectively.

[0092] 2. As attached Figure 5 ,9 As shown in Figure 10, for bracket 1 31, first pass the signal line 34 through hole 6 317, and then tightly embed the transducer 33 into the inner curved surface 1 315 coated with epoxy resin to complete the installation; similarly, for bracket 3 32, pass the two signal lines 34 through hole 8 327, and tightly embed the two transducers from both ends of column 5 323 into the inner curved surface 4 325 coated with epoxy resin to complete the installation.

[0093] 3. As attached Figure 4 , 8 As shown in Figure 9, for the installation of bracket 31, first pass the signal line 34 through hole 231, then fit bracket 31 with hole 411 of bracket 41 via post 312, and fit post 313 with curved surface 416. Further, the flat surface 311 of bracket 31 is embedded in the inner liner tube 23, and all mating parts are coated with epoxy resin for fixation. Similarly, bracket 32 ​​can be installed.

[0094] 4. As attached Figure 8 As shown, the signal wire 34 is passed through the fixing head 30, gasket 35, and bolt 36 in sequence above the hole 1112; the bracket 31 is positioned and fixed by the fixing head 30 placed in the hole 1112 in the flange 11 / flange 2; due to the positioning effect of the hole 1112, the inner liner tube 23 is also fixed; the signal wire is pulled out from the outside of the boss 15 and the tube sleeve 13 through the hole 4 using a thin hook.

[0095] 5. For example Figure 13 As shown, the signal line 34 is threaded through hole 141, and then through mounting base 14 and mounting tube 511 to enter instrument box 56.

[0096] 6. For example Figure 14 As shown, place the rubber ring 142 on the outer ring of the mounting base 14, and then fit the mounting tube 511 under the instrument box 51 onto its outer side; place the rubber ring and the instrument box 2 56, and tighten them with bolt 3 57; place the circuit board 54 into the instrument box 2 56 and fix it, connect the battery 55, electrically connect the signal line 34 to the circuit board 54, place the rubber ring 531 and the glass surface 53, tighten the cover 52, and apply the lead seal to complete the assembly.

[0097] 7. The types of brackets installed at both ends of the inner liner tube need further explanation: Bracket 1 and its matching bracket 2 are brackets for installing a single transducer, which are installed at the inlet and outlet sections of the flowmeter; while bracket 3 and its matching bracket 4 are brackets for installing a dual transducer, which are installed on the inner liner tube in the middle of the flowmeter. If there are multiple inner liner tubes, bracket 3 and its matching bracket 4 can be installed at the tail of the previous inner liner tube or at the front of the next inner liner tube. Only one section needs to be installed in the inner liner tube in the middle of each flowmeter tube body; since it does not affect the total sound path, it does not affect the calculation results.

[0098] The above examples illustrate the application of the flange-fixed transducer and sound path-connected large-diameter ultrasonic flow meter of the present invention in a DN300 water meter. However, the invention is not limited to the specific embodiments described above. 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 gas 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 ultrasonic flow meter with a flange-fixed transducer and continuous sound path, characterized in that: The system includes flange 1 (11); flange 2 (12); hole 1 (1112); pipe sleeve (13); fixed seat 1 (14); boss 1 (15); fixed seat 2 (16); inner liner 1 (21); partition 1 (211); inner liner 2 (22); partition 2 (221); fixed head (30); bracket 1 (31); transducer (33); signal line (34); bolt 1 (36); bolt 2 (37); bracket 2 (41); bracket 3 (32); bracket 4 (42); instrument box 1 (51); and protective shell (61). Inner liner 1 (21) and inner liner 2 (22) are installed together inside the pipe sleeve (13). Multiple brackets 2 (41) and multiple brackets 4 (42) are arranged perpendicular to the axis on the inner side of the inlet and outlet of inner liner 1 (21). Multiple brackets (41) are arranged inside the mouth; the two ends of brackets 2 and 4 are welded and fixed to the inside of the inner liner tube and one side of the partition plate, respectively; brackets 1 (31) and 3 (32) are fixed on brackets 2 (41) and 4 (42) respectively by column and hole cooperation; transducers (33) are embedded in brackets 1 (31) and 3 (32) respectively, and the transducers corresponding to the straight line on brackets 1 and 3 are paired up in pairs, so that in the same partition of inner liner tube 1 and inner liner tube 2, the two sets of sound channels formed by the two transducers form a straight line; one end of bracket 1 is fixed through the inside of the flange, and the signal line (34) of the transducer is connected to the instrument box (51) through the inner hole of the bracket, through the inner channel of the flange and the outside of the pipe sleeve, so as to realize a large-diameter ultrasonic flow meter with continuous sound path and maximized range ratio.

2. The flange-fixed transducer and sound path continuity large-diameter ultrasonic flow meter according to claim 1, characterized in that: The transducer (33) is tightly embedded in the curved surface (315) of the bracket (31), wherein the protrusion (331) is tightly fitted with the curved surface (318), the plane (332) coincides with the positioning surface (316), and the signal line (34) passes through the hole (317); for the bracket (32), the two transducers are tightly embedded in the curved surface (325) from both ends of the column (323), and the curved surfaces are tightly fitted, the plane (332) coincides with the positioning surface (326), and the signal line (34) passes through the hole (327).

3. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The bracket one (31) is tightly fitted with the hole seven (411) of the bracket two (41) through the column one (312), and the column two (313) is tightly fitted with the curved surface three (416). The lower plane of the straight rod of the bracket passes through the notch one (414) and coincides with the upper plane of the straight rod of the bracket two. The plane three (319) coincides with the protrusion one (413). Furthermore, the plane two (311) of the bracket one (31) is embedded in the inner liner tube three (23).

4. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The bracket three (32) is tightly fitted with the hole nine (421) of the bracket four (42) through the column four (322), and the column five (323) is tightly fitted with the curved surface five (426). The lower plane of the straight rod of the bracket three passes through the notch two (424) and coincides with the upper plane of the straight rod of the bracket four. In addition, the plane seven (321) of the bracket three (32) is embedded in the inner liner tube four.

5. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The bracket (31) is positioned and fixed by the fixing head (30) in the hole (1112) in the flange (11) and flange (12); further, the positioning surface (304) coincides with the positioning platform in the hole (1112), the rubber ring (303) contacts and seals with the inner liner tube (23) and the plane (311), the rubber ring (302) contacts and seals with the inner wall of the hole (1112), and the rubber ring (301) contacts and seals with the inner wall of the hole (1112) and the gasket (35); further, the bolt (36) presses the fixing head (30) with the gasket (35) to fix the inner liner tube (23); there is a hole (152) in the hole (1112), the hole (152) is located on the upper side of the bolt (36), and the bolt (37) is located at the upper end of the hole (1112).

6. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The bracket three (32) is positioned and fixed by the fixing head (30) placed in the hole of the fixing seat two (16); further, the positioning surface two (304) coincides with the positioning platform in the hole, the rubber ring four (303) contacts and seals with the inner liner tube three (23) and the plane seven (321), the rubber ring three (302) contacts and seals with the inner wall of the hole, and the rubber ring two (301) contacts and seals with the inner wall of the hole and the gasket (35); further, the bolt one (36) presses the fixing head (30) through the gasket (35) to fix the inner liner tube three (23).

7. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The partition plate 1 (211) and partition plate 2 (221) are located inside the metal inner liner tube 1 (21) and inner liner tube 2 (22), respectively. They are arranged in a grid pattern with a certain spacing in the horizontal and vertical directions, and are respectively connected to the inner walls of the metal inner liner tube 1 (21) and inner liner tube 2 (22) by welding. The inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 can be in multiple sets as needed. Furthermore, the inner liner tube 1, inner liner tube 3, inner liner tube 2, and inner liner tube 4 can be made of the same material and can be integrated into a single structure.

8. A flange-fixed transducer and a large-diameter ultrasonic flow meter with continuous sound path, as described in claim 1, characterized in that... The boss one (15) is connected to the inner side of flange one (11) or flange two (12) and the outer side of pipe sleeve (13). Furthermore, one side of the boss one has hole four (152) and the upper side has hole three (151); the inner side of the protective shell (61) coincides with the upper side of the boss one (15) and is fixed by screw (62) and hole three (151).

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