DN15 caliber through transmission type ultrasonic water meter transducer lead wire and sealing structure

Abstract

The present application belongs to the technical field of flow metering equipment, and particularly relates to a DN15 caliber through transmission type ultrasonic water meter transducer lead wire and sealing structure, aiming at solving the problems that the existing technology, i.e. the through transmission type ultrasonic DN15 caliber water meter, has a too small water flow gap in the pipe, a low metering range ratio caused by the use of a variable diameter conversion joint, and a gap between the six principles of the optimal solution of the ultrasonic water meter technology development, by changing and optimizing the transducer structure and layout, the sealing mode of the transducer and the intermediate flow guide pipe and the outer metal pipe, and the transducer lead wire mode, the problems are solved, the DN15 caliber is ensured to have a large sound path and a larger water flow gap in the meter, which is beneficial to the passage of conventional impurities in water, the overall sealing components are reduced, the transducer signal line lead-out operation is facilitated, at the same time, the structure is simple, safe and reliable, so that the present application has the characteristics of maximum metering range ratio, minimum starting flow, high measurement precision and high consistency in batch production.

Description

Technical Field

[0001] This invention belongs to the technical field of flow metering equipment, and specifically relates to a DN15 diameter through-beam ultrasonic water meter transducer lead wire and sealing structure. 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] Depending on the specific application requirements, the fluid metering industry or applications expect standard flow metering instruments that are compatible with a wide range of diameters and specifications, have low pressure loss, high accuracy, high reliability, no wear-resistant components, and are durable and economical. Currently, electromagnetic flow meters and ultrasonic flow meters are the most widely used all-electronic flow metering devices worldwide.

[0004] Ultrasonic flow meters have emerged alongside technological breakthroughs in their time-difference timing chips (between 2012 and 2017, international companies such as AMS, D-FLOW, and TI successively launched relatively advanced time-difference timing chips, currently achieving resolutions of 5-10 ps, ​​fully meeting the needs of water metering applications). In contrast to electromagnetic flow meters, ultrasonic flow meters sample using time-difference digital signals (while 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., capable of measuring liquids with flow velocities of 0.8–1 mm / s), wider range ratio, the ability to actively measure 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), and the ability to measure various low-viscosity liquids (while electromagnetic flow meters cannot measure low-conductivity liquids, such as pure water). In addition, they can also measure / meter gases such as fuel gas (while electromagnetic flow meters cannot measure gas flow).

[0005] So, how should we define the technological development direction and principles for upgrading and improving ultrasonic water meters? Generally, the main 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 crucial conditions for determining accuracy. The range ratio, under the condition of guaranteed metering accuracy, is the ratio of the commonly used flow rate to the minimum flow rate, reflecting the range that can be accurately measured; increasing the effective distance between ultrasonic transducers is a necessary condition for improving the range ratio. Clearly, the higher the metering accuracy and the larger the range ratio, the better the metering performance of the flow meter.

[0006] In recent years, the metering industry has seen significant improvements in the practical application of ultrasonic flow meters. The composition of an ultrasonic flow meter, besides the time-of-flight totalizer circuit, includes a transducer, transducer installation method, and flow channel structure. The performance of the former determines the minimum measurable flow rate, while the overall architecture of the latter determines the comprehensive performance and quality of the ultrasonic flow meter. Taking ultrasonic water meters as an example, especially under the constraints of the new water meter standards, the industry has clarified the direction of technological development. The optimal solution should follow the principles summarized below: (1) Principle of maximizing sound path: To achieve a large range ratio in ultrasonic water meters, especially for the most commonly used DN15 diameter, the sound path between ultrasonic transducers should be maximized. This is because a large range ratio is a crucial indicator for trade settlement and is the most important technical specification for water meters, unlike industrial flow meters. To achieve a large range ratio in ultrasonic water meters, the projected distance of the line connecting the two transducers in the main pipe in the direction of water flow should be maximized to obtain a larger range ratio and a smaller starting flow rate. (For water meters, the national standard increased the maximum value of the range ratio, or flow ratio, to R=1000 in 2018.)

[0007] Through theoretical analysis, the following conclusions can be drawn regarding the metering quality of ultrasonic flow meters: In the field of water metering, the range ratio R is defined as R=Q3 / Q1, where Q3 is the common flow rate corresponding to 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%).

[0008] Through in-depth analysis and derivation, this paper arrives at an important conclusion: For fluid passing through the flow meter pipeline, the measured starting flow rate (i.e., the minimum flow rate that the flow meter can sense and measure) Q q The lower (corresponding to its flow velocity V) q The lower the value, the lower the V. q The flow rate (Q1) is related to the resolution of the ultrasonic flow meter's time-of-flight chip and the pipe structure of the flow meter. Correspondingly, the minimum flow velocity V1 will also decrease proportionally. Typically, in practical applications, its empirical value is Q1 = (5~10)Q q (Q1 varies depending on the ultrasonic flowmeter circuit and transducer, resulting in overall zero drift, and the water resistance design of the flowmeter pipeline.) Therefore, for a given flowmeter diameter (where the time interval between Q3 and Q1 flowing through the flowmeter pipeline is equal), the relationship between the range ratio R and the distance L between the two transducers can be derived as follows: 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 water 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 water 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 / 10, 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: Increasing the projected distance L cos(α) between the two transducers in the direction of water flow in the flow meter pipeline can effectively improve the flow meter's range ratio R.

[0009] (2) Principle of through-beam installation between a pair of transducers: In through-beam installation, the acoustic signal is directly transmitted and received between a pair of transducers, thus the amplitude of the effective signal is the highest. Reflective installations, due to one or more reflecting surfaces, result in energy loss during acoustic wave reflection (ideally, when the reflecting surface is large enough, the energy loss is 10-20%, which generally does not affect measurement). Especially when the reflecting surface has an angular deviation or scale buildup after use, the energy loss can reach 40-60%, severely affecting normal measurement. Furthermore, the presence of reflecting surfaces complicates the installation structure, and improper handling of the water resistance distribution on the reflecting surface can also affect measurement accuracy.

[0010] (3) Consistency principle; The flow channel forming and processing technology of the ultrasonic water meter base has high component installation accuracy and consistency requirements, which determines the quality of mass production of flow meters. In particular, it is necessary to ensure that the distance between the emitting surfaces of the two transducers is fixed and not affected by differences in pipe section processing and transducer installation. Improving this level can reduce the range of individual error compensation and accuracy correction for the base meter, and reduce the complicated workload of manually correcting individual errors later.

[0011] (4) Pipe body sealing safety principle: In the case of an inner liner, in order to ensure sealing safety, local sealing should be used as much as possible rather than overall sealing to ensure the reliability and durability of the seal.

[0012] (5) Adaptability principle: Small-diameter flow meters are convenient for installing temperature sensors to meet the needs of heating metering; (6) Simple structure and easy assembly principle: The ultrasonic water meter has a simplified structure and a unique installation, which makes it easy to assemble as a whole, and it is stable, reliable and highly consistent.

[0013] Based on the above six principles, for small-diameter ultrasonic water meters, especially the most common DN15 diameter for civilian use, the most effective method is to build a built-in through-beam transducer structure and directly use an integral pipe section to process and manufacture a DN15 flow meter base.

[0014] According to the principle of maximizing sound path, to obtain better performance (small starting flow Q) q For ultrasonic flow meters, a pair of small-diameter, through-beam transducers must be installed within the DN15 straight pipe, with the transducer spacing as large as possible. Furthermore, compatibility with different regional water treatment and quality conditions must be considered. Based on experience, impurities in tap water are typically less than 3mm in diameter. For ultrasonic flow meters, a low-resistance filter needs to be installed at the front end. Due to its small area, based on experience with ordinary single-velocity mechanical flow meters, the mesh diameter needs to be Φ2.5–3mm to prevent clogging. Therefore, for fully electronic flow meters, it is generally best to ensure a minimum water flow clearance ≥3mm inside the flow meter base. This way, the filter only removes individual foreign objects like hair, allowing small particles to pass through, ensuring long-term use without clogging. Additionally, a series of issues need to be addressed, such as a simple and safe system sealing method and a convenient transducer lead-out structure (the lead-out must not be submerged in water). Currently, a safe and effective solution to these issues remains lacking.

[0015] According to the standards of the above principles, the existing technology still has defects or deficiencies.

[0016] Patent authorization announcement number CN 201503288 U discloses a base meter for an ultrasonic direct-through-beam flowmeter. As shown in the figure, the patent uses a large transducer (1MHz transducer, conventional convex dimensions: front end Φ17, rear end Φ21), which occupies a large space for installation and fixation. This increased volume necessitates larger piping, requiring segmented processing and assembly. This structure is not only complex and labor-intensive to install, but also requires multi-stage sealing, resulting in poor reliability. Since the piping is assembled in segments using nuts, this leads to component deformation and deviation, directly affecting the consistency of the flowmeter batch. Furthermore, the large transducer generates significant water resistance in the flow channel, and its flow path directly affects the accuracy of flow measurement at different flow velocities. Additionally, the patent does not provide a detailed description of the sealing of the transducer lead wires.

[0017] Patent publication number CN 201716054 U discloses another transducer through-beam mode, in which the transducer extends from the side of the pipe. Through-beam ultrasonic flow meters require that the two through-beam surfaces of the transducer be strictly parallel. However, this method of fixing the transducer with a single-hole insertion and no support below, and using the method of sealing and positioning by pressing the lower sealing ring with the transducer's convex edge as shown in the diagram, is extremely unreliable. With the transducer suspended in the waterway, under the impact of strong water flow, the pressure on the sealing surface is uneven and slightly tilted due to the lever torque (the compression of the sealing ring is regulated and cannot be too tight, so this surface generally cannot be used as the positioning surface). This poses a risk that the two through-beam surfaces of the transducer will not remain parallel. Experiments show that for plane waves, the sound energy loss caused by the non-parallelism of the two transducer surfaces is fatal. This method also has the problem of the durability of the single sealing ring.

[0018] Patent publication number CN 211317425 U proposes a small-diameter through-beam ultrasonic flow meter, which exhibits good stability in this through-beam mode. However, the standard pipe length for DN15 is specified as 165mm. If this mode is applied to a DN15 diameter, the sealing and lead-out method described in the patent necessitates a structure with a larger diameter intermediate pipe section to accommodate the through-beam transducer and ensure a minimum gap of ≥3mm. The two ends of the pipe must then be connected using a variable diameter connection as described in patent publication number CN 208223575 U to achieve the DN15 specification. This threaded variable diameter head method results in a shorter sound path and a lower measurement range than R, failing to adequately widen the gap between the two transducers, which contradicts the principle of maximizing sound path.

[0019] Further analysis of patent authorization announcement number CN 211317425 U reveals that ultrasonic water meters (flow meters) consist of three parts: a time-difference circuit system, a transducer, and the transducer installation mode and pipeline structure. Currently, time-difference circuit systems are mainly provided by AMS, D-Flow, and TI, and their accuracy already meets the application requirements of water meters. Therefore, improving the performance and quality of water meters is primarily determined by the transducer and its shape and structure, the combination of the transducer and the pipeline, and the installation structure within the pipeline.

[0020] Regarding the specifications of the ceramic transducer, the core component of ultrasonic transducers, the Water Meter Committee of the China Metrology Association has defined the application standards for transducers as follows: The specified vibration frequencies of the transducer ceramic plates are: 1MHz, 2MHz, and 4MHz. Common diameter-to-thickness ratios for ceramic sheets are: Φ12 / 2mm; Φ8 / 1mm; Φ8 / 0.5mm; The wavelengths corresponding to the material at each frequency are: 2.5mm, 1.25mm, 0.625mm. (Assume the speed of sound in a certain sound-conducting material at room temperature is 2500 m / s) Conventionally, the larger the transducer, the stronger the emitted sound wave, but the larger the installation size. Conversely, the higher the transducer frequency (i.e., the shorter the wavelength), the smaller its physical diameter and volume, making installation easier. Furthermore, the accuracy of its timing and triggering circuits is higher, and the time difference calculation is more precise. Early transducer manufacturing was less advanced, and reflective transducers suffered from sound wave loss, so most manufacturers used larger 1MHz transducers (using Φ12-14mm ceramic plates). In recent years, with advancements in precision manufacturing, the electro-acoustic conversion efficiency of smaller, higher-frequency transducers has been significantly improved, fully meeting application requirements. Especially for small-aperture ultrasonic through-beam systems, smaller transducers (Φ8mm ceramic plates) with frequencies of 2MHz or 4MHz can be selected. Therefore, including the 1mm thickness required for the encapsulation shell, the minimum transducer diameter can be as small as Φ10mm.

[0021] Once the transducer frequency and size are determined, the shape of the transducer, its integration with the pipeline, and its installation structure within the pipeline become the key factors determining its performance.

[0022] Patent authorization announcement number CN 211317425 U is a transducer-to-beam built-in solution that maximizes the distance between two transducers and can be well applied to diameters of DN20 and above. However, for DN15 water flow meters, if the transducer is to be built-in, the minimum gap between the water flow at the transducer position inside the pipe must be ≥3mm to ensure that impurities in the water can pass through smoothly.

[0023] Analysis of the implementation of this patent shows that if it is applied to a DN15 diameter water meter, i.e., using an internal transducer, and the transducer, i.e., the inner tube of the flow meter (becoming an integral unit), is fixed and sealed at both ends with metal pressure rings and sealing rings with built-in external threads, and the transducer lead wire is led out from the middle of the tube, then its minimum water flow gap can be calculated: The outer diameter of the DN15 flow meter pipe thread is 26.44mm (standard). To machine the internal thread, its safety thickness is at least 3.2mm (external thread height approximately 1.2mm, internal thread height 1mm, remaining wall thickness approximately 1mm); the minimum diameter of the transducer is Φ10mm (8mm ceramic resonator + 1mm protective shell on one side); inside the pipe, the outer tube thickness of the transducer support that is fixed in contact with the externally threaded metal pressure ring is at least 2.5mm (side sealing ring 1.5~2mm, transducer double-strand shield with outer sleeve lead wire smaller diameter Φ1.5mm, groove on the outside of the inner tube with a depth of 1.5mm, plastic groove with remaining wall thickness of 1mm). Therefore, the flow gap of the fluid passing through the transducer inside the pipe can be calculated as follows: (26.44mm-2×3.2mm-2×2.5mm-10mm) / 2=5.04mm / 2=2.52mm≤3mm.

[0024] Therefore, for a DN15 diameter transducer, the method of fixing and sealing the internal transducer with metal pressure rings at both ends of the pipe cannot ensure the safe passage of impurities in the water flow, and it is prone to clogging. It is necessary to use a middle pipe with a larger diameter and DN20-DN15 adapters at both ends, as described in patent publication number CN 208223575 U. In this case, the distance between the emitting surfaces of the two transducers is approximately L=63mm. Therefore, this mode violates the principle of maximizing the sound path, and the water meter's range is significantly reduced compared to R.

[0025] Based on the above analysis, the patent grant announcement number CN 211317425 The main reason why the U-shaped design cannot be directly applied to DN15 diameter pipes is that: the transducers are placed at both ends of a straight pipe of equal diameter. To facilitate the signal line from the middle of the pipe and for sealing purposes, metal pressure rings are used at both ends of the pipe to seal the inner liner. This requires thickening the outer ring of the inner liner for the sealing rings and the wiring, resulting in an excessively narrow water flow gap inside the pipe. Furthermore, this design uses internal pressure rings with external threads at both ends of the pipe, making assembly labor-intensive and inefficient. The presence of internal threads on the outer pipe also poses a safety hazard (easily scratched) due to the pressure sealing method used to install the sealing rings at both ends. Additionally, the overall sealing of the inner liner makes it inconvenient to install insertion-type temperature sensors due to waterproofing requirements. In particular, the narrow internal space between the inner pipe and the outer metal pipe makes it extremely difficult and time-consuming to assemble the transducer leads, which must run along the outer groove of the inner pipe and exit from the central hole (the longer portions of the leads at both ends pass inside the pipe, leaving no space for the excess wire ends).

[0026] In conclusion, for DN15 ultrasonic water meters, there is still a lack of effective solutions that can meet the above six principles as much as possible, while also being sealed, safe, and having convenient lead wires, based on currently published patents. Summary of the Invention

[0027] In view of the shortcomings of the existing technology, the present invention aims to solve the problem of reducing the overall sealing components and facilitating the lead-out operation of the transducer signal line by changing the transducer structure, the sealing method of the transducer and the intermediate guide pipe and the outer metal pipe, and the fixed installation method of the water meter totalizing circuit box and the flow meter base meter, so as to achieve a simple structure and safety and reliability while ensuring a loud sound range and a large water flow gap for DN15 diameter water meters.

[0028] It is evident that for an ultrasonic water meter with a length of 165mm and a diameter of DN15, if it is possible to install a through-beam transducer while ensuring a minimum flow gap of ≥3mm, and to place the transducer at both ends of the metal pipe as much as possible, the distance between the transducer's emitting surfaces can be calculated to be approximately 113mm. This distance is significantly greater than the 63mm distance with an adapter. From R=Q3 / Q1=βL [where α=0, cos(α)=1], it can be seen that after the improvement, the range ratio increases by 113 / 63=179.3%, achieving a qualitative leap. Furthermore, by appropriately reducing the diameter in the middle of the flow meter (while meeting pressure loss requirements), the range ratio, flow stability, and starting flow rate of the DN15 water meter can be further effectively improved (actual testing of this solution can achieve a starting flow rate Q...). q <0.4L / h).

[0029] This invention provides a transducer lead wire and sealing structure for a DN15 diameter through-beam ultrasonic water meter. The technical solution is as follows: the straight-through pipe of the ultrasonic flow meter is a uniform-diameter metal outer tube, which is laser-welded to a transducer lead wire mounting base and a temperature sensor mounting base on its outer side. Two irregularly shaped transducers are installed at both ends inside the straight-through pipe. These two transducers and the intermediate rectifier tube are connected by laser welding to form a double-through-beam transducer liner structure. This integral liner structure only has a partial seal with the inner side of the uniform-diameter metal outer tube, not a complete seal, allowing for a larger minimum water passage gap within the pipe. Therefore, for a given straight-through pipe length, for the most commonly used household DN15 diameter, a minimum water passage gap greater than 3mm can be achieved within the flow channel. This avoids the need for cumbersome large-diameter to small-diameter conversion joints for DN15 diameters. Thus, it not only achieves a stable maximum distance (sound path) between the two transducer emitting surfaces but also facilitates assembly and convenient lead-out of the transducer signal lines.

[0030] This invention relates to a transducer lead wire and sealing structure for a DN15 diameter through-beam ultrasonic water meter. Its features include: a uniform-diameter metal outer tube and three types of external thread forming structures, a shaped transducer, a ceramic plate assembly, a rectifier tube, a transducer lead wire fixing seat, a transducer lead wire fixing head, an instrument circuit box, a lead wire fixing cap, and a temperature sensor fixing seat; the DN15 diameter straight-through through-beam ultrasonic water meter has a uniform-diameter metal outer tube as its base; the shaped transducer consists of a shaped transducer structural component and a transducer flow guide cover; two shaped transducer structural components and the rectifier tube between them form a double through-beam transducer liner integral structure; the synergistic structure of the shaped transducer, transducer signal line, and sealing method ensures that... The two ends of the inner side of the metal outer tube can be installed and fixed with irregularly shaped transducer components without the need for pressure rings. This achieves a minimum water passage gap of more than 3mm in the water meter flow channel, avoiding the drawback of the existing DN15 diameter transducer through-beam installation, which requires a cumbersome large-diameter to small-diameter conversion joint for the pipe interface. As a result, a stable and maximized distance (sound path) is obtained between the two irregularly shaped transducer emitting surfaces, and the components are easy to assemble. With the uniform diameter metal outer tube as the central structure, and the transducer lead wire fixing seat, transducer lead wire fixing head, instrument circuit box, and lead wire fixing cap working together, a DN15 diameter straight-through through-beam ultrasonic water meter is formed, achieving the effect of maximizing the metering range ratio and minimizing the starting flow value.

[0031] In this invention, a ceramic plate assembly is installed in the middle of the irregularly shaped transducer structure; the middle of the irregularly shaped transducer structure is connected to the inner side of the outer ring by an upper support column and a lower support column, respectively; a positioning fixing bolt is installed in the lower support column; the fixing bolt is positioned by a blind hole; the inner hole of the upper support column is a wire outlet oblique hole, one end of which communicates with the inside of the irregularly shaped transducer, and the other end communicates with the central through hole of the transducer lead wire fixing head. The transducer signal line is led out from the middle of the irregularly shaped transducer through the wire outlet oblique hole and the central hole of the transducer lead wire fixing head to the integrator circuit board.

[0032] The function of the inclined hole in the middle of the upper support column is as follows: Although the transducer lead wire fixing seat is located inside the external threads at both ends of the equal-diameter metal outer tube, the transducer signal line can be led out through the inclined hole. Therefore, the irregular transducer structure can be installed as close as possible to the inner sides of both ends of the equal-diameter metal outer tube without considering the positional misalignment caused by the transducer lead wire fixing seat being located inside the external threads. Thus, it can effectively increase the distance between the two irregular transducer emitting surfaces, that is, increase the sound path and improve the range ratio R.

[0033] Since the gap and cross-sectional area for fluid passage in the middle of the irregularly shaped transducer structure are the smallest, the middle of the irregularly shaped transducer structure described in this application is connected to the inner side of the outer ring by two support columns, an upper support column and a lower support column, instead of multiple columns. The purpose of this is to reduce obstruction, increase the cross-sectional area for water passage, and reduce pressure loss.

[0034] The transducer lead wire fixing seat is located on the outside of the equal-diameter metal outer tube and on the inside of the external thread. The transducer lead wire fixing seat and the equal-diameter metal outer tube are connected by laser welding. The transducer lead wire fixing head is located at the lower end inside the transducer lead wire fixing seat, and has a side sealing ring that seals with the inner side of the transducer lead wire fixing seat. The positioning platform provides height positioning to ensure the height and flatness of the transducer lead wire fixing head. This ensures that the lower sealing ring of the transducer lead wire fixing head has a reasonable compression amount and allows the lower part of the transducer lead wire fixing head to be embedded inside the irregularly shaped transducer structural component, thus positioning and fixing the irregularly shaped transducer structural component. Furthermore, the lower sealing ring below the transducer lead wire fixing head is used to seal the irregularly shaped transducer structural component; the side sealing ring is used to seal the inner side of the transducer lead wire fixing seat.

[0035] The elastic washer is located above the transducer lead wire fixing head and below the lead wire fixing cap. The lead wire fixing cap presses and fixes the transducer lead wire fixing head by applying force to the elastic washer.

[0036] The connection between the rectifier tube and the transducer structural components at both ends is achieved by adhesive bonding or laser welding at the joint (laser welding is now widely used in metal and plastic welding), forming an integral structure for the inner lining of the double-beam transducer. The sealing ring on the rectifier tube serves to fix the rectifier tube during installation and to prevent water from flowing between it and the inner wall of the equal-diameter metal outer tube; it does not provide an overall seal.

[0037] The aforementioned dual-beam transducer liner integral structure is secured by a transducer lead wire fixing head pressing and fixing it from the upper part of the transducer lead wire fixing seat, while a fixing bolt is positioned from the lower part of the irregular transducer structural component, ensuring a very secure fit. The fixing bolt is located in the lower support column of the transducer; furthermore, the fixing bolt consists of an external threaded nut, a fixing bolt rod, and a spring. The internal hole of the external threaded nut is a hexagonal hole for easy installation. Its positioning is achieved by the fixing bolt rod engaging with the corresponding blind hole on the inner side of the equal-diameter metal outer tube. Installation of the fixing bolt: Insert the fixing bolt components, namely the spring and the fixing bolt rod, into the blind hole of the lower support column of the irregular transducer structural component, and tighten the external threaded nut to secure it in place with the internal thread of the blind hole of the lower support column.

[0038] The length of the inner liner of the dual-beam transducer is 0.3mm shorter on one side than the equal-diameter metal outer tube. Its function is to ensure that the pressure on the sealing gasket is mainly borne by the mating metal tube when the flow meter is installed. This can effectively protect the inner liner tube and prevent it from deforming due to less stress during long-term use.

[0039] Installation of the dual-beam transducer inner liner tube structure inserted into the equal-diameter outer metal tube: Press down the fixing rod, insert one end of the dual-beam transducer inner liner tube structure into the equal-diameter outer metal tube. Note that it should be offset from the position of the corresponding blind hole one on the inner side of the equal-diameter outer metal tube. That is, do not let one side of the fixing rod enter the blind hole one at first. After pressing down the other end of the fixing rod and inserting the entire dual-beam transducer inner liner tube structure into the equal-diameter outer metal tube, use a tool to hold the support columns of the two irregular transducer structural components, rotate the transducer sleeve, so that the two fixing rods at both ends simultaneously enter their respective blind holes one, and complete the installation and fixation.

[0040] The equal-diameter metal outer tube has external threaded interfaces at both ends. There are three ways to form these external threaded interfaces: First, the wall thickness is sufficient to allow the external threads to be machined directly onto the equal-diameter metal outer tube; second, when using a thinner equal-diameter metal outer tube, a pre-machined externally threaded sleeve is fitted onto it and fixed to the equal-diameter metal outer tube by laser welding; third, when using an equal-diameter metal outer tube of moderate thickness, part of the wall thickness is removed so that a pre-machined externally threaded sleeve can fit onto it, and the two are fixed to each other by laser welding.

[0041] For the first forming method mentioned above, where the wall thickness allows for direct machining of external threads on the equal-diameter metal outer tube, although the outer tube is slightly thicker, its advantage lies in ease of processing. It meets the technical requirement that the minimum gap in the irregularly shaped transducer is greater than 3mm, allowing impurities to pass through smoothly. This is because the inner sides of both ends of the equal-diameter metal outer tube of this invention do not require metal pressure rings with external threads, and the transducer lead wire does not pass through the outer side of the inner liner. Therefore, for a DN15 diameter, using an equal-diameter metal outer tube with a wall thickness of 2.5mm (external thread height approximately 1.2mm), the transducer's outer tube does not need a wiring groove to guide the transducer signal line to the outlet in the middle of the tube. Therefore, an outer tube thickness of 1.8mm fully meets the strength requirements. Thus, after improvements to the DN15 diameter equal-diameter metal outer tube and its internal structure, the minimum gap in the middle of the irregularly shaped transducer within the equal-diameter metal outer tube can be calculated as follows: (26.44mm-2×2.5mm-2×1.8mm-10mm) / 2=7.84mm / 2=3.92mm>3mm. Compared with patent publication number CN 208223575 U, it not only saves materials, but also fully meets the requirement of impurities passing through smoothly.

[0042] For the second forming method mentioned above, to save materials, a thinner-walled, equal-diameter metal outer tube is selected, such as an outer tube wall thickness of 1.0mm (compliant with the standard CJ / T 151-2016 for thin-walled stainless steel pipes for domestic water use). This differs from the first method, which directly forms external threads at both ends of the equal-diameter metal outer tube. In this case, the externally threaded tube uses a threaded sleeve, welded to the equal-diameter metal outer tube using laser welding. In this scenario, the wall thickness of the equal-diameter metal outer tube is 1.0mm, not 2.5mm as in the first forming method. Therefore, the outer diameter of the thread remains unchanged at 26.44mm, the length of the externally threaded tube is 11mm, the thickness is 2.0mm (of which the thread height is 1.2mm), and the inner diameter is 22.44mm. The wall thickness of the equal-diameter metal outer tube is 1.0mm, and the outer diameter is 22.44mm. An externally threaded tube with a length of 11 mm and a thickness of 2.0 mm is fitted onto both ends of a metal outer tube with a wall thickness of 1 mm. The externally threaded tube and the metal outer tube are then welded together at the joint using a laser to form a single unit. The minimum gap between the inner side of the metal outer tube and the irregularly shaped transducer is calculated as follows: (26.44mm - 2×3mm - 2×1.8mm - 10mm) / 2 = 6.84mm / 2 = 3.42mm > 3mm. This meets the requirement for impurities to pass through smoothly. While meeting the strength requirements of the metal casing of the DN15 water meter base, this external thread formation method saves on outer tube material compared to patent publication number CN 208223575 U and the first forming method mentioned above. For the third forming method mentioned above, when selecting a uniform diameter metal outer tube with a suitable thickness, if increased strength is required, for example, a wall thickness of 1.5mm can be chosen. The outer diameter of the thread remains unchanged at 26.44mm. The length of the external threaded tube is 11mm, the thickness is 2.0mm (of which the thread height is 1.2mm), and the inner diameter is 22.44mm. The wall thickness of the uniform diameter metal outer tube is 1.5mm. 0.25mm is machined off each end of the diameter and 11mm is machined off the length. The 11mm long and 2.0mm thick external threaded tube is fitted onto both ends of the machined 1mm thick metal outer tube. Similar to the second forming method mentioned above, the external threaded tube and the metal outer tube with 0.25mm machined off each end are welded together at the joint using a laser to form a whole. From this, the minimum gap between the uniform diameter metal outer tube and the irregularly shaped transducer can be calculated as follows: (26.44mm - 2 × 3mm - 2 × 1.8mm - 10mm) / 2 = 6.84mm / 2 = 3.42mm > 3mm. This result is consistent with the second forming method and also allows impurities to pass through smoothly. Therefore, for metal outer tubes with a wall thickness of approximately 1.5mm, this forming method can be used. Compared to patent publication number CN 208223575 U and the first forming method mentioned above, this forming method saves on outer tube material.

[0043] Regarding the second and third types of thin-tube equal-diameter metal outer tube external thread formation methods mentioned above, a double-beam transducer liner integral structure is formed by connecting two irregularly shaped transducer structural components with the rectifier tube. The positioning and fixing method is as follows: the middle part of the rectifier tube is sealed and fixed in the blind hole two in the middle part of the rectifier tube by bolts and sealing ring two in the rectifier tube fixing seat; the two ends are pressed and fixed from the upper part of the transducer lead wire fixing seat by two lead wire fixing heads. Thus, a double-beam transducer liner integral structure is formed with three positioning and fixing points, which is very firm.

[0044] The ceramic plate assembly is placed in a blind hole in a shaped transducer structure. The ceramic plate is bonded to the bottom of the blind hole by a two-component A and B adhesive. The positive and negative electrodes of the ceramic plate are soldered to the PCB, and the transducer signal lines are also soldered to the PCB.

[0045] The transducer lead wires have two modes: The first step involves encapsulating a ceramic sheet within the blind holes of the irregularly shaped transducer structure. After soldering the leads to the PCB, the transducer signal lines are then soldered. At this stage, the transducer guide cap is not installed. Instead, a complete double-beam transducer liner structure is inserted into a uniform-diameter metal outer tube. Two fixing bolts are inserted into the blind holes within the uniform-diameter metal outer tube to secure the complete double-beam transducer liner structure. Next, the transducer leads are passed through the outgoing angled holes and exit from the transducer lead holder. This completes the assembly and exit of the irregularly shaped transducer and its signal lines within the uniform-diameter metal outer tube. To achieve IP68 waterproofing, a flat-headed thin tube is used to inject two-component A and B curing adhesive into the irregularly shaped transducer through the outgoing angled holes within the transducer lead holder, ensuring a tight bond between the irregularly shaped transducer structure and the transducer guide cap.

[0046] Secondly, the transducer signal line is connected via an internal connector and an external connector, and leads out from the transducer lead wire mounting base. The connector is fixed inside the connector mounting hole, and the bottom of the connector is soldered to the positive and negative terminals of the ceramic plate on the PCB via wires. Therefore, before the entire structure of the dual-beam transducer liner is inserted into the equal-diameter metal outer tube, two-component A and B curing adhesive can be injected into the transducer, and then the transducer flow guide cover can be attached, so that the irregularly shaped transducer structure and the transducer flow guide cover are tightly integrated into one unit.

[0047] The instrument circuit box is located outside the equal-diameter metal outer tube and consists of a lower casing and an upper casing. The integrator circuit board, display screen, and battery are located inside the instrument circuit box. The lower casing of the instrument circuit box and the outer ring of the transducer lead wire fixing seat are cylindrically fitted together and sealed by a sealing ring. The lead wire fixing cap has two functions: first, it presses the transducer lead wire fixing head tightly by applying force to the elastic washer; second, it is used to press the lower casing of the instrument circuit box. In this way, the lower casing of the instrument circuit box is fixed in a very simple way, saving fixing components. According to actual needs, waterproof glue can be potted inside the instrument circuit box to achieve an IP68 protection level.

[0048] In this invention, if the heat energy carried by the fluid is to be measured, a temperature sensor needs to be installed separately. Since the integral structure of the double-beam transducer liner composed of the irregular transducer and the rectifier tube does not require a waterproof seal between the inner side of the metal outer tube, a temperature sensor mounting base can be installed near the outlet of the equal-diameter metal outer tube when performing heat metering applications. The temperature sensor can be installed in the temperature sensor mounting base, and the temperature measuring rod of the temperature sensor is obliquely inserted outside the transducer guide cover at the outlet end, without affecting the measurement of the fluid.

[0049] In summary, compared with the prior art, the present invention has outstanding substantive features and significant progress, specifically manifested in the following ways: First, for a given length of DN15 or smaller diameter ultrasonic water meter base, this invention, by modifying the lead wires and sealing structure of the built-in irregularly shaped transducers, allows two built-in irregularly shaped transducer components to be placed close to both ends of a straight metal pipe of equal diameter, without requiring a reduction in diameter connection using a large-to-small connector threaded conversion method in the water meter's straight-through pipe. This ensures a minimum water flow gap greater than 3mm within the DN15 diameter straight-through pipe, facilitating the safe passage of impurities. This maximizes the distance between the emitting surfaces of the two transducers, i.e., maximizes the sound path, thereby enabling the DN15 or smaller diameter ultrasonic water meter to achieve a maximized range ratio and minimized starting flow.

[0050] Secondly, the function of the inclined hole structure in the middle of the upper support column of the irregular transducer structure is as follows: Although the transducer lead wire fixing seat is located inside the external threads at both ends of the equal-diameter metal outer tube, since the transducer signal line can be led out through the inclined hole, the irregular transducer structure can be installed close to the inner sides of both ends of the equal-diameter metal outer tube without considering the positional misalignment caused by the transducer lead wire fixing seat being located inside the external threads. Therefore, it can increase the distance between the two irregular transducer emitting surfaces as effectively as possible, that is, increase the sound path and improve the range ratio R.

[0051] Third, since the gap and cross-sectional area for fluid passage are minimized in the middle part of the irregularly shaped transducer structure, the middle part of the irregularly shaped transducer structure and the inner side of the outer ring are connected by two support columns, an upper support column and a lower support column, instead of multiple columns. The purpose of this is to reduce obstruction, increase the cross-sectional area for water passage, and reduce pressure loss.

[0052] Fourth, the socket and plug-type transducer lead wire and sealing structure of the present invention cleverly realize the signal transmission connection between the transducer signal line and the water meter circuit board through the internal and external connection plug and the internal connection socket. This method not only eliminates the need for overall sealing of the inner liner tube, but also facilitates the installation of irregularly shaped transducers and the lead wire of the transducer signal line.

[0053] Fifth, the post-encapsulated transducer flow guide cover and transducer signal line lead-out and sealing structure of the present invention do not adopt the overall sealing method of the inner liner tube. Under the condition of ensuring the minimum water passage gap, it also achieves signal transmission with fewer components and convenient lead-out of transducer signal lines to the totalizing circuit board.

[0054] Sixth, the transducer lead wire fixing head of the present invention is height-positioned by the positioning platform inside the transducer lead wire fixing seat. This ensures that the lower sealing ring of the transducer lead wire fixing head has a reasonable amount of compression, and also allows the lower part of the transducer lead wire fixing head to be embedded inside the irregular transducer structural component, thereby playing the role of positioning and fixing the irregular transducer structural component.

[0055] Seventh, the thickness of the equal-diameter metal outer tube and the pipe thread interfaces at both ends of the outer side of the present invention can be formed in three ways. All three forming methods can reduce material costs compared with the thicker equal-diameter metal outer tube in patent publication number CN 208223575U, while facilitating processing and functionality.

[0056] Eighth, in this invention, for the external thread forming method of using a metal thick tube of equal diameter, for the overall structure of the inner liner of the double-beam transducer, two transducer lead wire fixing heads are pressed and fixed from the upper part of the sleeve, while two positioning fixing bolts are positioned from the lower part of the tubular transducer, which is very secure.

[0057] Ninth, in this invention, for the external thread formation method of using a thin metal tube of equal diameter, a double-beam transducer liner integral structure is formed by connecting two irregularly shaped transducer structural components with the rectifier tube. The positioning and fixing method is as follows: the middle part of the rectifier tube is sealed and fixed by bolts and sealing rings in the rectifier tube fixing seat; the two ends are pressed and fixed from the top of the transducer lead wire fixing seat by two transducer lead wire fixing heads. Thus, the inner liner tube is positioned and fixed in three places, which is very firm.

[0058] Tenth, the lead wire fixing cap of the present invention achieves the function of replacing one and replacing two. It presses the transducer lead wire fixing head by applying force to the elastic washer; at the same time, it presses and fixes the lower shell of the instrument circuit box, reducing the number of fixing devices for the lower shell.

[0059] Eleventh, the connection between the rectifier tube and the irregularly shaped transducer structural components at both ends of the present invention is completed by adhesive bonding or laser welding at the joint, forming an integral structure of a double-beam transducer liner. The purpose of this structure is to ensure that the distance between the emitting surfaces of the two irregularly shaped transducers is consistent during mass production and that the distance remains constant during the assembly or use of the flow meter. The distance between the emitting surfaces of the two irregularly shaped transducers determines the range ratio, thus ensuring the consistency of the water meter parameters and greatly facilitating the testing and calibration of the water meter.

[0060] Twelfth, the length of the overall structure of the inner lining of the dual-beam transducer described in this invention is 0.3mm shorter on one side than the equal-diameter metal outer tube. Its function is that when connecting with external pipes and installing water meter fittings, the pressure on the sealing gasket is mainly borne by the metal pipe opening. This can effectively protect the inner lining tube, so that it is subjected to less stress and does not deform during long-term use.

[0061] Thirteenth, the change in the lead wire and internal sealing structure of the transducer of the DN15 diameter through-beam ultrasonic water meter of the present invention, so that its straight pipe structure makes it convenient to use laser welding to fix the temperature sensor at the outer end of the outlet of the equal diameter metal outer pipe, and install the temperature sensor to facilitate heat energy measurement.

[0062] Fourteenth, the DN15 diameter through-beam ultrasonic water meter transducer lead wire and sealing structure of the present invention have two transducer lead wire fixing seats located at both ends of the equal diameter metal outer tube, which provides the possibility and convenience for setting and installing a flow control valve in the middle of the flow tube.

[0063] The various external thread formation structures for straight metal tubes with equal outer diameter, the irregularly shaped transducers and their sealing structures, the positioning and fixing structure of the irregularly shaped transducers and the sealing structure of the leads through the transducer lead fixing head, the adhesive bonding or laser welding of the irregularly shaped transducers and rectifier tubes into one piece, and the connection structure between the lower shell of the instrument circuit box and the equal-diameter metal outer tube proposed in this application are all proposed based on years of theoretical research and engineering research practice, and have been verified to be effective in practice. They are novel, creative and practical. Attached Figure Description

[0064] Figure 1 This is a schematic diagram of the lead wire and sealing structure of a DN15 diameter through-beam ultrasonic water meter transducer. Figure 2 This is a schematic diagram of the lead wire structure of a DN15 diameter straight-through through-beam ultrasonic water meter connector; Figure 3 This is a schematic diagram of a welded threaded sleeve structure for a thin-walled metal outer tube of equal diameter; Figure 4 This is a schematic diagram of a welded threaded sleeve structure for a moderately thick-walled metal outer tube of equal diameter; Figure 5 This is an exploded view of the irregularly shaped transducer connector lead wire structure; Figure 6 This is a side view of the water meter and a schematic diagram of the internal support column structure of the irregularly shaped transducer; Figure 7 This is a schematic diagram showing the mounting position of a DN15 diameter through-beam ultrasonic water meter temperature sensor. Figure 8 This is a schematic diagram showing the installation position of the temperature measuring rod of a DN15 diameter straight-through ultrasonic water meter temperature sensor. In the picture: 11. Equal diameter metal outer tube; 111. External thread; 112. External threaded tube; 22. Transducer lead wire fixing seat; 221. Sealing ring one; 233. Positioning platform; 23. Transducer lead wire fixing head; 231. Lower sealing ring; 232. Side sealing ring; 24. Elastic washer; 25. Lead wire fixing cap; 28. Rectifier tube fixing seat; 29. ​​Bolt; 291. Sealing ring two; 30. Ceramic plate assembly; 33. Irregularly shaped transducer structural component; 34. Transducer flow guide cover; 341. Flow guide cover lower groove; 301. A and B adhesives; 302. Ceramic plate; 303. PCB; 304. Socket; 305. Plug; 26. Fixing bolt; 261. Fixing bolt rod; 262. External thread nut; 263. Spring; 113. Blind hole one; 443. Blind hole two; 331. Upper support column; 332. Lower support column; 334. Outlet wire oblique hole; 333. Length; 44. Rectifier tube; 441. Sealing ring three; 442. Laser welded seam; 55. Instrument circuit box; 55A. Lower shell of instrument circuit box; 55B. Upper shell of instrument circuit box; 553. Integrator circuit board; 554. Display screen; 555. Battery; 56. Transducer signal line; 27. Temperature sensor mounting bracket; 271. Temperature sensor. Detailed Implementation

[0065] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples. Example 1

[0066] As attached Figure 1The diagram shows a DN15 diameter through-beam ultrasonic water meter transducer lead wire and sealing structure, including a 2.5mm thick 304 stainless steel equal-diameter metal outer tube 11, a shaped transducer, a rectifier tube 44, a transducer lead wire fixing seat 22, a transducer lead wire fixing head 23, an instrument circuit box 55, and a lead wire fixing cap 25. The DN15 diameter through-beam ultrasonic water meter has an equal-diameter metal outer tube 11 as its base. The shaped transducer consists of a shaped transducer structural component 33 and a transducer flow guide cover 34. Due to the qualitative change in the lead-out and sealing method of the transducer signal line 56, the shaped transducer can be installed at both ends of the equal-diameter metal outer tube 11 without the need for metal pressure rings. Its internal structure satisfies the requirement that the minimum water passage gap in the flow channel is >3mm. Therefore, the method described in patent publication number CN 208223575 U, which requires a large-to-small conversion connector to connect the two ends of a straight pipe to convert it to a DN15 diameter, is solved. Thus, the irregularly shaped transducer installation method used in this application maximizes the distance between the emitting surfaces of the two transducers, i.e., maximizes the sound path. The irregularly shaped two transducer structural components 33 are connected by a rectifier tube 44 to form a double-beam transducer liner integral structure. With the equal-diameter metal outer tube 11 as the center, and the transducer lead wire fixing seat 22, transducer lead wire fixing head 23, instrument circuit box 55, and lead wire fixing cap 25 working together, a DN15 diameter straight-through beam ultrasonic water meter is formed, achieving maximum metering range ratio and minimum starting flow value.

[0067] A ceramic plate assembly 30 is installed in the blind hole in the middle of the irregularly shaped transducer structural component 33; the middle part of the irregularly shaped transducer structural component 33 and the inner side of the outer ring are respectively connected by an upper support column 331 and a lower support column 332; a fixing bolt 26 is installed in the lower support column 332 of the transducer; the fixing bolt 26 is positioned by a blind hole 113; the inner hole of the upper support column 331 is a wire outlet oblique hole 334, one end of which communicates with the middle interior of the irregularly shaped transducer, and the other end communicates with the central through hole of the transducer lead wire fixing head 23. The transducer signal line 56 is led out from the middle interior of the irregularly shaped transducer through the wire outlet oblique hole 334 and the central hole of the transducer lead wire fixing head 23 to the integrator circuit board.

[0068] The function of the lead wire oblique hole 334 in the upper support column 331 is as follows: Although the transducer lead wire fixing seat 22 is located inside the external threads 111 at both ends of the equal diameter metal outer tube 11, since the transducer signal line 56 can be led out through the lead wire oblique hole 334, the irregular transducer structural component 33 can be installed close to the inner sides of both ends of the equal diameter metal outer tube 11 without considering the positional misalignment caused by the transducer lead wire fixing seat 22 being located inside the external threads 111. Therefore, it can effectively increase the distance between the two irregular transducer emitting surfaces, that is, increase the sound path and improve the range ratio R.

[0069] As attached Figure 6 As shown, since the gap in the middle part of the irregular transducer structure 33 where the transducer is located is the smallest, i.e. the cross-sectional area through which the fluid passes, the middle part of the irregular transducer structure in this embodiment is connected to the inner side of the outer ring by two support columns, the upper support column 331 and the lower support column 332, instead of multiple columns. This helps to increase the cross-sectional area through which the water passes and reduce pressure loss.

[0070] The transducer lead wire fixing seat 22 is located outside the equal-diameter metal outer tube 11 and inside the external thread 111; the transducer lead wire fixing seat 22 and the equal-diameter metal outer tube 11 are connected by laser welding; the transducer lead wire fixing head 23 is located at the lower end inside the transducer lead wire fixing seat 22, and its side has a side sealing ring 232 that seals with the inner side of the transducer lead wire fixing seat 22. The positioning table 233 is used for height positioning to ensure the height and flatness of the transducer lead wire fixing head 23. It can ensure that the lower sealing ring 231 at the bottom of the transducer lead wire fixing head 23 has a reasonable amount of compression, and can also embed the lower part of the transducer lead wire fixing head 23 into the interior of the irregular transducer structural component 33, thereby playing the role of positioning and fixing the irregular transducer structural component 33. The elastic washer 24 is located above the transducer lead wire fixing head 23 and below the lead wire fixing cap 25. The lead wire fixing cap 25 presses and fixes the transducer lead wire fixing head 23 by applying force to the elastic washer 24.

[0071] The connection between the rectifier tube 44 and the irregularly shaped transducer structural components 33 at both ends is achieved by adhesive bonding or laser welding at the joint, forming an integral structure for the inner lining of the double-beam transducer. This stable structure ensures that the distance between the emitting surfaces of the two irregularly shaped transducers remains constant, greatly improving the consistency of flowmeter mass production. The sealing ring 441 on the rectifier tube 44 serves to fix the rectifier tube during installation and to prevent water from flowing between it and the inner wall of the metal tube; it does not provide an overall seal.

[0072] The integral structure of the dual-beam transducer liner is fixed by the transducer lead wire fixing head 23 pressing and fixing it from the upper part of the transducer lead wire fixing seat, while the fixing bolt 26 is positioned and fixed from the lower support column 332 of the irregular transducer structural component 33. The fixing bolt 26 is located in the lower support column 332 of the transducer; further, the fixing bolt 26 is composed of an external thread nut 262, a fixing bolt rod 261, and a spring 263. The fixing bolt 26 is fixed by screwing the external thread nut 262, which has a hexagonal inner hole, into the internal thread of the lower support column 332, and the fixing bolt rod 261 is positioned by engaging the corresponding blind hole 113 on the inner side of the equal-diameter metal outer tube 11. Installation of the fixing bolt 26: Insert the fixing bolt assembly, namely the spring 263 and the fixing bolt rod 261, into the blind hole with internal thread in the lower support column 332 of the irregular transducer structural component, and tighten the external thread nut 262.

[0073] As attached Figure 1 As shown, the length of the overall structure of the inner liner of the dual-beam transducer is 333mm shorter than that of the metal outer tube of equal diameter by 0.3mm on one side. Its function is that when installing the water meter union, the pressure on the sealing gasket is mainly borne by the mating metal pipe, which can effectively protect the inner liner tube and prevent it from deforming due to less stress during long-term use.

[0074] Installation of a dual-beam transducer liner assembly into a constant-diameter metal outer tube 11: Press down the fixing rod 261 to retract its head, and insert one end of the irregularly shaped transducer structure into the constant-diameter metal outer tube 11. Note that it should be staggered from the corresponding blind hole position on the inside of the constant-diameter metal outer tube 11; that is, do not allow one side of the fixing rod 261 to enter the blind hole of the constant-diameter metal outer tube 11 initially. After pressing down the other end of the fixing rod 261 and inserting the entire dual-beam transducer liner assembly into the constant-diameter metal outer tube, use a fork-shaped tool to hold the upper support column 331 and the lower support column 332, and rotate to allow the two fixing rods 261 at both ends of the dual-beam transducer liner assembly to simultaneously enter their respective blind holes 113 within the constant-diameter metal outer tube 11, completing the installation and fixing.

[0075] As attached Figure 1 As shown, for a DN15 diameter tube, a uniform-diameter metal outer tube 11 with a wall thickness of 2.5mm (external thread height approximately 1.2mm) is selected; the outer tube thickness of the irregularly shaped transducer structural component is 1.8mm. Therefore, the minimum gap between the irregularly shaped transducer structural components inside the uniform-diameter metal outer tube can be calculated as follows: (26.44mm-2×2.5mm-2×1.8mm-10mm) / 2=7.84mm / 2=3.92mm>3mm, which fully meets the requirement for impurities to pass through smoothly, and saves more material than the outer tube in patent authorization announcement number CN 211317425 U.

[0076] The ceramic plate assembly 30 is placed in a blind hole in the irregular transducer structure. It includes a ceramic plate 302 bonded to the bottom of the blind hole by a two-component A and B adhesive 301, the positive and negative electrodes of the ceramic plate being soldered to a PCB 303, and the transducer signal line 56 also being soldered to a PCB 303.

[0077] The assembly process of the transducer signal line 56 is as follows: After encapsulating the ceramic sheet 302 and PCB 303 in the blind holes of the irregularly shaped transducer structure, the transducer signal line 56 is soldered. At this time, the transducer rectifier cover 34 is not installed yet. Instead, the entire structure of the double-beam transducer liner is inserted into the equal-diameter metal outer tube 11. The two fixing rods 261 are inserted into their respective blind holes 113 in the equal-diameter metal outer tube to fix the entire structure of the double-beam transducer liner. After that, the transducer lead wire is passed through the outgoing wire oblique hole 334 and out through the transducer lead wire fixing seat 22, completing the installation of the irregularly shaped transducer in the equal-diameter metal outer tube 11 and the lead wire of the transducer. To achieve IP68 waterproofing, a flat-headed thin tube is used to inject two-component A and B curing adhesive into the transducer through the oblique outlet hole 334 inside the transducer lead wire fixing bracket, tightly bonding the irregularly shaped transducer structural component 33 and the transducer guide cover 34 into a single unit. It should be noted that the lower groove 341 of the lower outer ring of the transducer guide cover 34 is bonded with the A and B adhesive, further solidifying the transducer guide cover 34 and the irregularly shaped transducer structural component 33 into a robust whole.

[0078] The instrument circuit box 55 is located outside the equal-diameter metal outer tube 11 and consists of a lower casing 55A and an upper casing 55B. The totalizing circuit board 553, display screen 554, and battery 555 are located inside the instrument circuit box 55. The lower casing 55A of the instrument circuit box mates with the cylindrical outer ring of the transducer lead wire fixing seat 22, and the two are sealed by a sealing ring 221. The lead wire fixing cap 25 has two functions: first, it presses the transducer lead wire fixing head 23 by applying force to the elastic washer 24; second, it is used to press the lower casing 55A of the instrument circuit box. In this way, the lower casing 55A of the instrument circuit box is fixed in a cost-effective and simple way. According to actual needs, waterproof glue can be potted inside the instrument circuit box to achieve an IP68 protection level. Example 2

[0079] As attached Figure 4 , 7The diagram shows a DN15 through-beam ultrasonic water meter transducer lead wire and sealing structure, including a 1.6mm thick 304 stainless steel equal-diameter metal outer tube 11, a shaped transducer, a rectifier tube 44, a transducer lead wire fixing seat 22, a transducer lead wire fixing head 23, an instrument circuit box 55, a lead wire fixing cap 25, and a temperature sensor 271; the DN15 diameter through-beam ultrasonic water meter has an equal-diameter metal outer tube 11 as its base casing; the shaped transducer consists of a shaped transducer structural component 33 and a transducer flow guide cover 34. Due to the qualitative change in the structure of the transducer lead wire and sealing method, the shaped transducer can be installed at both ends of the equal-diameter metal outer tube 11 without the need for pressure rings, and its structure meets the requirement that the minimum water passage gap in the flow channel is >3mm. Therefore, the method described in patent publication number CN 208223575 U, which requires a large-to-small conversion connector threaded to both ends of a straight pipe to convert it to a DN15 diameter, is solved. This maximizes the distance between the two transducer emitting surfaces, i.e., maximizes the sound path. The two irregularly shaped transducer structural components 33 are connected by a rectifier tube 44 to form a double-beam transducer liner integral structure. With the equal-diameter metal outer tube as the central framework, and the transducer lead wire fixing seat 22, transducer lead wire fixing head 23, lead wire fixing cap 25, instrument circuit box 55, and temperature sensor mounting seat 27 working together, a DN15 diameter straight-through beam ultrasonic water meter is formed, achieving maximum metering range ratio and minimum starting flow value.

[0080] A ceramic plate assembly 30 is installed in the middle of the irregularly shaped transducer structural component 33; the middle of the irregularly shaped transducer structural component 33 and the inner side of the outer ring are respectively connected by an upper support column 331 and a lower support column 332; the inner hole of the upper support column 331 is a wire outlet oblique hole 334, one end of which communicates with the middle interior of the irregularly shaped transducer, and the other end communicates with the central through hole of the transducer lead wire fixing head 23. The transducer signal line 56 is led out from the middle interior of the irregularly shaped transducer through the wire outlet oblique hole 334 and the central hole of the transducer lead wire fixing head 23.

[0081] The function of the inclined hole 334 for the output of the irregular transducer in the middle of the upper support column 331 is as follows: Although the transducer lead wire fixing seat 22 is located inside the external threads 111 at both ends of the equal-diameter metal outer tube 11, since the transducer signal line 56 can be led out through the inclined hole 334, the irregular transducer structural component 33 can be installed as close as possible to the inner sides of both ends of the equal-diameter metal outer tube 11 without considering the positional misalignment caused by the transducer lead wire fixing seat 22 being located inside the external threads 111. Therefore, it can effectively increase the distance between the two irregular transducer emitting surfaces, that is, increase the sound path and improve the range ratio R.

[0082] Since the gap and cross-sectional area for fluid passage are minimized in the middle part of the irregularly shaped transducer structure 33 where the transducer is located, the middle part of the irregularly shaped transducer structure in this embodiment is connected to the inner side of the outer ring by two support columns, the upper support column 331 and the lower support column 332, instead of multiple columns. This helps to increase the cross-sectional area for water passage and reduce pressure loss.

[0083] The transducer lead wire fixing seat 22 is located outside the equal-diameter metal outer tube 11 and inside the external thread 111; the transducer lead wire fixing seat 22, the rectifier tube fixing seat 28, and the temperature sensor fixing seat 27 are connected to the equal-diameter metal outer tube 11 by laser welding; the transducer lead wire fixing head 23 is located at the lower end inside the transducer lead wire fixing seat 22, and has a side sealing ring 232 that seals against the inner side of the transducer lead wire fixing seat 22, and is height-positioned by the positioning platform 233 inside the lead wire fixing seat 22. The lead wire fixing head 23 is used to ensure the height and flatness of the lead wire fixing head 23. It ensures that the lower sealing ring 231 at the bottom of the lead wire fixing head 23 has a reasonable amount of compression, and can also embed the lower part of the lead wire fixing head 23 into the interior of the irregular transducer structure 33, so as to play the role of positioning and fixing the irregular transducer structure 33. The elastic washer 24 is located above the lead wire fixing head 23 and below the lead wire fixing cap 25. The lead wire fixing cap 25 presses and fixes the transducer lead wire fixing head 23 by applying force to the elastic washer 24.

[0084] The connection between the rectifier tube 44 and the transducer structural components 33 at both ends is achieved by adhesive bonding or laser welding at the joint, forming an integral structure for the double-beam transducer liner. For the thin-walled, equal-diameter metal outer tube 11, as shown in the attached... Figure 4 As shown, the middle part of the rectifier tube 44 is sealed and fixed by bolts 29 and sealing ring 291 inside the rectifier tube fixing seat 28. The sealing ring 441 on the rectifier tube 44 serves to fix the rectifier tube and prevent water from flowing between it and the inner wall of the metal outer tube of the same diameter during installation, but does not provide an overall seal.

[0085] For the overall structure of the dual-beam transducer liner installed inside the thin tube, in addition to being fixed by bolts 29 and sealing rings 291 in the rectifier tube mounting base 28, the two transducer lead wire fixing heads 23 are also pressed and fixed from the top of the transducer lead wire fixing base, forming three positioning and fixing points. This stable structure can ensure that the distance between the two irregularly shaped transducer emitting surfaces of the overall structure of the dual-beam transducer liner remains constant, greatly improving the consistency of the flow meter's mass production performance.

[0086] Installation process: Insert the entire inner liner structure of a double-beam transducer into the equal-diameter metal outer tube 11, tighten the bolt 29 with sealing ring 291 in the rectifier tube fixing seat 28, and fix it in the blind hole 443 of the rectifier tube 44 to complete the fixing of the entire inner liner tube.

[0087] The overall length of the inner liner of the dual-beam transducer is 333mm, which is 0.3mm shorter on one side than the equal-diameter metal outer tube. Its function is to ensure that when installing the flow meter union, the pressure on the sealing gasket is mainly borne by the mating metal tube, which can effectively protect the inner liner tube and prevent it from deforming due to less stress during long-term use.

[0088] This second embodiment is as shown in the appendix. Figure 4 As shown, the DN15 diameter metal outer tube has a wall thickness of 1.6mm and a threaded outer diameter that remains unchanged at 26.44mm. The length of the threaded tube is 11mm, the thickness is 2.0mm (of which the thread height is 1.2mm), and the inner diameter is 22.44mm. The wall thickness of the equal-diameter metal outer tube is 1.6mm, and 0.3mm is machined off each end, and 11mm is machined off the length. The 11mm long, 2.0mm thick threaded tube is fitted over the outer ends of the machined 1mm thick metal outer tube. The threaded tube and the 0.3mm machined-off metal outer tube are then welded together at the joints at both ends using a laser to form a single unit. From this, the minimum gap between the equal-diameter metal outer tube and the irregularly shaped transducer can be calculated as follows: (26.44mm - 2×3mm - 2×1.8mm - 10mm) / 2 = 6.84mm / 2 = 3.42mm > 3mm. The result satisfies the requirement that impurities can pass through smoothly and saves material compared to the outer tube in patent authorization announcement number CN 211317425 U.

[0089] The ceramic plate assembly 30 is placed in a blind hole in the irregular transducer structure. The ceramic plate 302 is bonded to the bottom of the blind hole by a two-component A and B adhesive 301. The positive and negative electrodes of the ceramic plate are soldered to the PCB 303, and the transducer signal line 56 is also soldered to the PCB 303.

[0090] The assembly process of the transducer signal line 56 is as follows: After encapsulating and installing the ceramic plate 302 and PCB 303 in the blind hole of the irregular transducer structure, the transducer signal line 56 is soldered. At this time, the transducer guide cover 34 is not installed. Instead, the entire structure of the double-beam transducer liner is inserted into the metal outer tube 11 of equal diameter. The middle part of the rectifier tube 44 is sealed and fixed in the blind hole 443 in the middle part of the rectifier tube by the bolt 29 and the sealing ring 291 in the rectifier tube fixing seat 28. The two ends are pressed and fixed from the top of the transducer lead wire fixing seat 22 by two lead wire fixing heads 23. Thus, the entire structure of the double-beam transducer liner is positioned and fixed in three places, which is very firm. Next, the transducer signal line 56 is passed through the outgoing oblique hole 334 and out of the transducer lead-out wire fixing seat 22. Then, the transducer flow guide cover 34 can be fastened, completing the installation of the irregular transducer in the uniform diameter metal outer tube and the lead-out of the transducer signal line. To achieve IP68 waterproofing, a flat-head thin tube is used to inject two-component A and B curing adhesive into the irregular transducer through the outgoing oblique hole 334 from inside the transducer lead-out wire fixing seat 22, so that the irregular transducer structural component 33 and the transducer flow guide cover 34 are tightly bonded together. It should be noted that the flow guide cover groove 341 on the lower outer ring of the transducer flow guide cover 34 is bonded with the A and B adhesive, which can bond the transducer flow guide cover 34 and the irregular transducer structural component 33 together.

[0091] The instrument circuit box 55 is located outside the equal-diameter metal outer tube 11 and consists of a lower casing 55A and an upper casing 55B. The totalizing circuit board 553, display screen 554, and battery 555 are located inside the instrument circuit box 55. The lower casing 55A of the instrument circuit box mates with the cylindrical outer ring of the transducer lead wire fixing seat 22, and the two are sealed by a sealing ring 221. The lead wire fixing nut 25 has two functions: first, it presses the transducer lead wire fixing head 23 by applying force to the elastic washer 24; second, it is used to press the lower casing 55A of the instrument circuit box. In this way, the bottom casing 55A of the instrument circuit box is fixed in a very economical way. According to actual needs, waterproof glue can be potted inside the instrument circuit box to achieve an IP68 protection level.

[0092] In this second embodiment, it is necessary to measure the heat energy carried by the fluid, so in addition to flow measurement, a temperature sensor 271 also needs to be installed. Since the integral structure of the double-beam transducer liner composed of the irregular transducer and the rectifier tube 44 does not require a waterproof seal between the inner side of the equal-diameter metal outer tube, for temperature measurement, the temperature sensor 271 is directly inserted into the temperature sensor mounting base 27. Since the temperature sensor mounting base 27 is close to the outlet, placing the temperature sensor outside the transducer guide cover at the outlet will not affect the measurement of the fluid.

[0093] The above two examples illustrate the implementation and application of the transducer lead wire and sealing structure of the DN15 diameter through-beam ultrasonic water meter and heat meter in this invention. However, this invention is not limited to the specific embodiments described above. Any modifications or variations made based on the content of this invention shall fall within the scope of protection claimed by this invention.

Claims

1. A DN15 diameter through-beam ultrasonic water meter, characterized in that... The system includes a constant-diameter metal outer tube (11), an external thread (111), an external threaded tube (112), a shaped transducer structural component (33), a transducer guide cover (34), an outgoing oblique hole (334), a rectifier tube (44), a transducer lead wire fixing seat (22), a transducer lead wire fixing head (23), a lead wire fixing cap (25), and an instrument circuit box (55). The transducer lead wire fixing seat (22) is located outside the constant-diameter metal outer tube (11) and inside the external thread (111). The transducer lead wire fixing seat (22) and the constant-diameter metal outer tube (11) are connected by laser welding. The transducer lead wire fixing head (23) is located inside the transducer lead wire. The lower end of the transducer lead wire fixing seat (22) has a side sealing ring (232) on its side that seals with the inner side of the transducer lead wire fixing seat (22). The positioning table (233) is used for height positioning to ensure the height and flatness of the transducer lead wire fixing head (23). It ensures that the lower sealing ring (231) at the bottom of the transducer lead wire fixing head (23) has a reasonable compression amount, and can also embed the lower part of the transducer lead wire fixing head (23) into the irregular transducer structure (33), thus playing the role of positioning and fixing the irregular transducer structure (33). The lower sealing ring (231) below the transducer lead wire fixing head (23) is used to seal the transducer structure (33). 3) Sealing; The irregularly shaped transducer consists of an irregularly shaped transducer structural component (33) and a transducer guide cover (34), which are installed at both ends inside the equal-diameter metal outer tube (11); the two irregularly shaped transducers are connected to the rectifier tube (44) to form a double-beam transducer liner integral structure; a ceramic plate assembly (30) is installed in the middle of the irregularly shaped transducer structural component (33); the middle of the irregularly shaped transducer structural component (33) and the inner side of the outer ring are respectively connected by an upper support column (331) and a lower support column (332); a fixing bolt (26) is installed in the lower support column (332); the fixing bolt (26) is positioned by a blind hole (113); the upper support column (331) is installed in the middle of the outer ring. The hole is a wire-out oblique hole (334), one end of which is connected to the middle interior of the irregular transducer, and the other end is connected to the central through hole of the transducer lead wire fixing head (23). The transducer signal line (56) is led out from the inside of the irregular transducer through the wire-out oblique hole (334) and the central hole of the transducer lead wire fixing head (23) to the totalizing circuit board (553). The transducer signal line (56) is connected to the plug (305) through the socket (304) and led out from the upper end of the transducer lead wire fixing seat (22). The socket (304) is fixed in the socket fixing hole. The bottom of the socket is soldered to the positive and negative terminals of the ceramic plate (302) on the PCB (303) through the wire.

2. The DN15 diameter through-beam ultrasonic water meter according to claim 1, characterized in that: The connection between the rectifier tube (44) and the irregularly shaped transducers on both sides is completed by adhesive bonding or by laser welding at the joint, forming an integral structure of the double-beam transducer liner.

3. A DN15 diameter through-beam ultrasonic water meter according to claim 2, characterized in that: The aforementioned dual-beam transducer liner integral structure is installed inside a uniform-diameter metal outer tube (11). When the thickness of the uniform-diameter metal outer tube (11) is sufficient to directly machine external threads (111), the dual-beam transducer liner integral structure is fixed by the transducer lead wire fixing head (23) pressing and fixing it from the upper part of the transducer lead wire fixing seat (22), while the fixing bolt (26) is used for lower positioning and fixing from the lower support column (332) of the transducer structural component (33). The fixing bolt (26) is located in the lower support column (332), and the fixing bolt (26) is... The device consists of an external thread nut (262), a fixing rod (261), and a spring (263). The fixing rod (261) is fixed by screwing the external thread nut (262) with a hexagonal inner hole into the internal thread of the lower support column (332) and by inserting the fixing rod (261) into the corresponding blind hole (113) on the inner side of the metal outer tube (11) of the same diameter to complete the positioning. Installation of the fixing bolt (26): Insert the spring (263) and the fixing rod (261) into the blind hole of the lower support column (332) of the irregular transducer structure and tighten the external thread nut (262) of the fixing bolt.

4. A DN15 diameter through-beam ultrasonic water meter according to claim 2, characterized in that: The length (333) of the integral structure of the inner lining of the dual-beam transducer is 0.3 mm less than that of a single side of the equal-diameter metal outer tube.

5. A DN15 diameter through-beam ultrasonic water meter according to claim 1, characterized in that: The equal-diameter metal outer tube (11) has external threads (111) at both ends. There are three ways to form the threaded interface: First, the wall thickness of the equal-diameter metal outer tube (11) is sufficient to allow the pipe thread to be directly machined on the outer tube; Second, when a thinner equal-diameter metal outer tube is selected, a pre-processed external threaded tube (112) is fitted on it and fixed with the equal-diameter metal outer tube (11) by laser welding; Third, when a metal outer tube (11) of moderate thickness is selected, part of the wall thickness of the equal-diameter metal outer tube (11) is removed, a pre-processed external threaded tube (112) is fitted on it, and the two are fixed with laser welding. All three ways of forming the threaded interface can ensure that the minimum gap between the equal-diameter metal outer tube and the irregular transducer is greater than 3mm.

6. A DN15 diameter through-beam ultrasonic water meter according to claim 5, characterized in that: When using a thin and moderately thick metal outer tube (11) with external thread forming method, the positioning and fixing method of the overall structure of the double-beam transducer liner is as follows: the middle of the rectifier tube (44) is fixed by bolts (29) and sealing ring two (291) in the rectifier tube fixing seat (28); the two ends of the overall structure of the double-beam transducer liner are pressed and fixed from the top of the transducer lead wire fixing seat (22) by two transducer lead wire fixing heads (23), thus forming three positioning and fixing points for the overall structure of the double-beam transducer liner.

7. A DN15 diameter through-beam ultrasonic water meter according to claim 1, characterized in that: Assembly of the irregularly shaped transducer and its signal line: After encapsulating the ceramic sheet (302) and PCB (303) in the blind hole of the irregularly shaped transducer structural component (33), the transducer signal line (56) is soldered on the PCB (303). The entire structure of the double-beam transducer liner is inserted into the equal-diameter metal outer tube (11), and the two fixing rods (261) are inserted into the blind hole (113) of the equal-diameter metal outer tube (11) for fixation. Then the transducer signal line is assembled. The signal line (56) passes through the outgoing inclined hole (334) and emerges from the upper end of the transducer lead wire fixing seat (22), completing the assembly and lead-out of the irregular transducer and the transducer signal line in the metal outer tube of equal diameter; in order to achieve IP68 waterproof, a flat-head thin tube is used to inject A and B glue (301) into the interior of the irregular transducer through the outgoing inclined hole (334) from the transducer lead wire fixing seat (22), so that the irregular transducer structural parts and the transducer guide cover are integrated into one.

8. A DN15 diameter through-beam ultrasonic water meter according to claim 1, characterized in that: The instrument circuit box (55) is located outside the equal-diameter metal outer tube (11) and consists of a lower shell (55A) and an upper shell (55B). The totalizing circuit board (553), the display screen (554), and the battery (555) are located inside the instrument circuit box (55). The lower shell (55A) of the instrument circuit box is fitted with the outer cylindrical ring of the transducer lead wire fixing seat (22), and there is a sealing ring (221) between them. The lead wire fixing cap (25) has two functions: first, it presses the transducer lead wire fixing head (23) by applying force to the elastic washer (24); second, it is used to fix the lower shell (55A) of the instrument circuit box.

9. A DN15 diameter through-beam ultrasonic water meter according to claim 1, characterized in that: A temperature sensor mounting base (27) is installed on the outside of the outlet end of the equal-diameter metal outer tube (11), and the temperature sensor (271) is installed in the temperature sensor mounting base (27).

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