Centering lead wire and sealing structure of DN15 ultrasonic wave opposite radiation type water meter

Abstract

The application belongs to the technical field of flow metering equipment, and particularly relates to a centering lead-out wire and sealing structure of a DN15 ultrasonic wave opposite-shooting water meter, which aims to solve the problem that the existing technology, i.e. the opposite-shooting ultrasonic wave DN15 caliber water meter, has a too small water flow gap in the pipe, a low metering range ratio caused by a variable-diameter conversion joint, and a gap from the six principles of the optimal solution of the ultrasonic wave water meter technology development. A full-sealing special lead-out wire channel is arranged for the transducer signal wire, and a metal wire-sealing pipe is arranged, so that the ultrasonic wave transducer is arranged in a close-to-equal-diameter metal outer pipe opposite-shooting layout, and the signal wire is conveniently led out from the middle of the pipe. The application takes the equal-diameter metal outer pipe as the center structure, and realizes the maximization of the metering range ratio and the minimization of the starting flow value under the condition of ensuring that there is a sufficient water flow gap in the water meter pipe, through the optimization and cooperation of the transducer lead-out wire fixing seat, the metal wire-sealing pipe and the transducer lead-out wire fixing head.

Description

Technical Field

[0001] This invention belongs to the technical field of flow metering equipment, and specifically relates to a central lead wire and sealing structure for a DN15 ultrasonic through-beam water meter. Background Technology

[0002] In the era of the Internet of Things, big data, artificial intelligence, and industrial automation, the replacement of mechanical or electromechanical flow meters with fully electronic flow meters has become an irreversible trend in the 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 (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 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] Therefore, it is necessary to 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:

[0008] 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%).

[0009] 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 flowmeter pipeline can effectively improve the flowmeter's range ratio R.

[0010] (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.

[0011] (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.

[0012] (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.

[0013] (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.

[0014] 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.

[0015] 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.

[0016] According to the standards of the above principles, existing technologies still have defects or deficiencies.

[0017] Patent authorization announcement number CN 201503288 U discloses a base plate for an ultrasonic direct-through-beam flow meter. As shown in the figure, the patent uses a large 1MHz transducer with a conventional convex front diameter of 17mm and a rear diameter of 21mm. The transducer's installation and fixing occupy a large space. 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 flow meter 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's lead wires.

[0018] 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.

[0019] 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 pipe, 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 be connected using a converter head, as described in patent publication number CN 208223575 U, to achieve the DN15 specification. This threaded converter 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.

[0020] Further analysis of patent authorization announcement number CN 211317425 U reveals that ultrasonic water 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.

[0021] 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 waves, 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. Therefore, most manufacturers used larger 1MHz transducers with ceramic plates of 12-14mm diameter. In recent years, with advancements in precision manufacturing, the electro-acoustic conversion efficiency of smaller, higher-frequency transducers has significantly improved, fully meeting application requirements. Especially for small-aperture ultrasonic beam transmission, smaller diameter 8mm ceramic plates and 2MHz or 4MHz transducers can be selected. Adding the 1mm thickness required for the encapsulation shell, the minimum transducer diameter can be as small as Φ10mm.

[0022] 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.

[0023] 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.

[0024] 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, where the transducer and the flow meter inner tube are integrated into a single structure, and both ends are fixed and sealed 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 the minimum clearance for water flow 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 10mm (8mm ceramic resonator + 1mm protective shell on one side); inside the pipe, the outer tube thickness of the transducer bracket 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 1.5mm, groove on the outside of the inner tube with a depth of 1.5mm, plastic groove with remaining wall thickness 1mm).

[0025] 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.

[0026] Therefore, for a DN15 diameter, 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, i.e., the method according to 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 range is significantly reduced to R.

[0027] 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 due to the risk of scratches from the sealing method of pressing the sealing rings at both ends. Additionally, the complete 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 metal outer pipe forces the two transducer leads to 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, making the operation extremely difficult and the assembly labor-intensive and time-consuming.

[0028] 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

[0029] In view of the shortcomings of the existing technology, this application proposes 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 water meter base, 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.

[0030] It is evident that for an ultrasonic water meter with a length of 165mm and a diameter of DN15, while installing a through-beam transducer and ensuring a minimum flow gap of ≥3mm, the transducer is placed at both ends inside a metal pipe. This allows us to calculate that the distance between the transducer's emitting surfaces is approximately 113mm, significantly greater than the 63mm distance with an adapter. From R=Q3 / Q1=βL [where α=0, cos(α)=1], we can see that the improved range ratio increases by 113 / 63=179.3%, representing 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).

[0031] This invention provides a centered lead-out wire and sealing structure for a DN15 ultrasonic through-beam water meter. The technical solution is as follows: The DN15 diameter straight-through through-beam ultrasonic water meter of this invention has a base meter outer tube that is a straight-through, equal-diameter metal outer tube. The transducers are installed at both ends inside the equal-diameter metal outer tube. To solve the problem of leading the signal lines of a pair of through-beam transducers out from the middle of the equal-diameter metal outer tube while ensuring a minimum water passage gap >3mm within the water meter flow channel, a fully sealed lead-out wire channel is specifically designed for the transducer signal lines. By installing a wire sealing tube, the problem of sealing the wiring between the irregularly shaped transducer structure and the rectifier tube in the channel is solved. This allows the irregularly shaped transducer structure to be installed as close as possible to the inner sides of both ends of the equal-diameter metal outer tube, achieving a stable and maximized distance (sound path) between the two transducer emitting surfaces. It eliminates the need for the adapter-type diameter connection method described in patent publication number CN208223575 U. This new layout of transducer lead wires and sealing structure has achieved substantial results. It forms a DN15 diameter straight-through ultrasonic water meter structure with convenient signal line lead-out in the middle, with the central framework of an equal-diameter metal outer tube, transducer lead wire fixing seat, wire sealing tube, transducer lead wire fixing head, instrument circuit box, lead wire fixing cap, and temperature sensor working together. This achieves the maximization of the metering range ratio and the minimization of the starting flow value while ensuring that the water flow gap in the pipe is >3mm.

[0032] This invention relates to a central lead-out wire and sealing structure for a DN15 ultrasonic through-beam water meter. Its features include: a uniform-diameter metal outer tube, a shaped transducer, a rectifier tube, a lead-out wire channel, a wire-passing sealing tube, a transducer lead-out wire fixing seat, a transducer lead-out wire fixing head, a water meter instrument circuit box, a lead-out wire fixing cap, and a temperature sensor fixing seat. The DN15 diameter through-beam ultrasonic water meter has a base outer tube of uniform diameter with external threads at both ends for easy connection to external pipelines. The shaped transducer is assembled from a shaped transducer structural component and a transducer guide cover. The rectifier tube and the shaped transducers at both ends are connected by adhesive bonding or laser welding to form a double through-beam transducer inner liner tube integral structure. By setting an internal lead-out wire channel and installing a wire-passing sealing tube, the design is modified as described in patent authorization announcement number CN 211317425. The U-shaped ultrasonic water meter uses an integrated sealing method with external thread metal pressure rings at both ends inside the metal outer tube. This allows the transducer signal line to be safely and conveniently led out from the middle of the equal-diameter metal outer tube, resulting in a qualitative change in the structure of the transducer lead line and the sealing method. Therefore, under the new method, a DN15 diameter ultrasonic water meter with a transducer through-beam type, a centrally located lead line and sealing structure is formed, which maximizes the metering range ratio and minimizes the starting flow value.

[0033] The irregularly shaped transducer of this invention consists of an irregularly shaped transducer structural component and a transducer guide cover. An ultrasonic transducer ceramic plate assembly is encapsulated in the center of the irregularly shaped transducer structural component. The center of the irregularly shaped transducer structural component is connected to the inner side of the outer ring by an upper support column and a lower support column, respectively. A fixing bolt is installed inside the lower support column of the transducer. The fixing bolt is positioned by a blind hole. The inner hole of the upper support column is a wire-out oblique hole, one end of which communicates with the interior of the irregularly shaped transducer, and the other end communicates with the lead-out wire channel through the wire-out oblique hole, leading the transducer signal line to the center blind hole three on the outer side of the rectifier tube, and soldering it to the central hole PCB. The main lead-out wire is soldered on the central hole PCB, and the transducer signal line is led out through the central hole of the transducer lead-out wire fixing seat.

[0034] Because the transducer signal lines can be routed through three locations—the outgoing oblique holes, the lead-out channels, and the blind holes on the outside of the rectifier tube—and soldered and led out onto the PCB with the center hole, irregularly shaped transducer components can be installed close to the inner sides of both ends of the uniform-diameter metal outer tube without considering the location of the transducer lead-out mounting brackets or other factors. Therefore, this transducer signal line lead-out method allows the distance between the two transducer emitting surfaces to reach its maximum value, i.e., the maximum sound path, resulting in a large range ratio R.

[0035] Because the gap and cross-sectional area for fluid passage in the middle part of the irregularly shaped transducer structure are small, the middle part of the irregularly shaped transducer structure described in this application is connected to the inner side of the outer ring by an upper support column and a lower support column, instead of multiple columns. The purpose is to reduce obstruction, increase the cross-sectional area for water passage, and reduce pressure loss. In addition, the horizontal outlet hole of the inclined outlet hole is to extend the thickness of the upper support column to connect with the rectifier tube. In this way, it can both avoid increasing the area of ​​water passage inside the obstruction and allow the transducer signal line to pass through the blind hole three in the middle of the outer side of the rectifier tube.

[0036] The transducer lead wire fixing seat is located in the middle of the outer side of the equal-diameter metal outer tube; 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 on the side that seals with the inner side of the transducer lead wire fixing seat; there is a lower sealing ring below for sealing irregularly shaped transducer structural components; the positioning surface inside the lead wire fixing seat provides height positioning to ensure the height and flatness of the transducer lead wire fixing head. This ensures that the lower sealing ring below the 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 rectifier tube, thus serving to press, position, and fix the rectifier tube.

[0037] 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.

[0038] The connection between the rectifier tube and the transducer structural components at both ends: except for the position corresponding to the lead wire channel, the other mating surfaces are connected by a tight fit of convex and concave surfaces, which can make the components fit tightly and stably; when mating, a wire sealing tube and a sealing ring should be placed at the mating point of the lead wire channel, and then the two should be mated; at the joint, with the assistance of the clamp, the connection is made by adhesive or by laser welding at the joint, forming a stable overall structure of the inner liner tube of the double-beam transducer.

[0039] The aforementioned dual-beam transducer inner liner tube structure is secured by a transducer lead wire fixing head that presses and fixes the middle of the outer side of the rectifier tube from within the transducer lead wire fixing seat. Two fixing bolts are positioned from the lower support column of the irregularly shaped transducer, forming three positioning and fixing points. The fixing bolts are located within the lower support column of the transducer. Furthermore, each fixing bolt consists of an external threaded nut, a fixing bolt rod, and a spring. The internal hole of the external threaded nut is hexagonal for easy installation. Positioning is achieved by inserting the fixing bolt rod into the corresponding blind hole on the inner side of the equal-diameter metal outer tube. Installation of the fixing bolt: Insert the fixing bolt assembly, i.e., the spring and fixing bolt rod, into the blind hole of the lower support column of the irregularly shaped transducer structure, and tighten the external threaded nut to secure it in place.

[0040] The length of the inner liner tube of the dual-beam transducer is 0.3mm shorter on each side than that of the equal-diameter outer metal tube. Its function is to ensure that the pressure of the sealing gasket is mainly borne by the mating metal pipe ends when installing the water meter union. This can effectively protect the inner liner tube, so that it is subjected to less stress and does not deform during long-term use.

[0041] A ceramic plate assembly is encapsulated in the second blind hole in the middle of the irregularly shaped transducer structure to form a transducer. After encapsulating the ceramic plate assembly, the transducer signal lines are soldered. At this time, the transducer guide cover is not installed yet. Instead, the transducer signal lines are sent through the outgoing oblique hole and the lead-out channel to the third blind hole in the middle of the rectifier tube and soldered to the PCB with the center hole. The specific operation process of leading the transducer signal lines to the middle of the rectifier tube is as follows: the lead-out channel is set inside the support column on the irregularly shaped transducer structure and inside the tube wall of the rectifier tube. The specifications of a single signal line are: 12 copper wires with a diameter of 0.08mm inside, and an outer sheath with a diameter of 0.6mm. The PTFE wire has a smooth and hard surface and is resistant to high temperatures. For a welded double-beam transducer liner, two signal wires, a single positive signal wire and a single negative signal wire, are inserted into the oblique outlet hole from the center of the transducer. At the other end of the oblique outlet hole, a tool is used to guide the wire end from the lead-out channel inlet. The wire is then pushed through the transducer opening and into the blind hole three in the middle of the rectifier tube. Because the wire surface is hard and smooth, this wire feeding process is easily completed. The central hole PCB is located at the bottom of the blind hole three and is tightly mated to the edge of the blind hole three. The central hole PCB is located at the outlet of the lead-out channel, and its edge has a notch. The transducer signal lines are led out to the front of the PCB via the center hole for soldering. After the transducer signal lines are soldered, the flow guide cover is attached, completing the process of leading the transducer signal lines from the inner liner tube of the double-beam transducer to the blind hole three in the middle of the rectifier tube. To achieve IP68 waterproofing, a flat-headed thin tube is used to open from the upper end of the inclined outlet hole. Two-component A and B waterproof curing adhesive is injected into the interior of the irregularly shaped transducer through the inclined outlet hole. Note: The outlet hole, including the upper end of the inclined outlet hole, must be completely filled. In this way, the interior of the irregularly shaped transducer structure, including the outlet hole, and the transducer flow guide cover are tightly integrated, achieving a waterproof seal for the outlet hole.

[0042] The function of the lead-out channel and the lead-out sealing tube is as follows: Since the connection between the rectifier tube and the transducer structural components at both ends is completed by adhesive bonding or laser welding at the joint, this connection method can ensure a firm and stable connection between the two, but it cannot guarantee that the internal joint is waterproof. Therefore, the lead-out sealing tube and the sealing ring on it serve to seal the lead-out channel of the transducer signal line from the lead-out oblique hole to the rectifier tube and to ensure that the transducer signal line passes smoothly through.

[0043] The installation sequence for inserting the entire inner liner tube structure of a dual-beam transducer into the equal-diameter outer metal tube is as follows: Press down the fixing rod to retract it into the lower support column. Insert one end of the entire inner liner tube structure into the equal-diameter outer metal tube, ensuring it is offset from the corresponding blind hole one on the inner side of the equal-diameter outer metal tube. Do not allow one side of the fixing rod to enter the blind hole one initially. Press down the other end of the fixing rod, and after the entire inner liner tube structure of the dual-beam transducer is fully inserted into the equal-diameter outer metal tube, use a tool to clamp and rotate the upper and lower support columns, allowing both fixing rods at both ends of the entire inner liner tube structure to simultaneously enter their respective blind holes, completing the assembly and fixing. After this step, through the inner hole of the transducer lead-out mounting base, solder a ground wire, the two positive terminals of the two transducer signal lines, and three lead-out wires onto the PCB in the center hole of the rectifier tube blind hole three, completing the lead-out of the two transducer signal line bus.

[0044] The wall thickness of the uniform-diameter metal outer tube is sufficient to allow for direct machining of external threaded interfaces at both ends of the DN15 diameter tube body. A metal tube with a wall thickness of 2.5mm and an external thread height of 1.2mm is selected. While this type of metal tube is slightly thicker, its advantage lies in ease of processing and its ability to meet the technical requirement of a minimum gap >3mm in the center of the irregularly shaped transducer, allowing impurities to pass through smoothly. The outer tube of the irregularly shaped transducer structural component does not have a sealing structure but instead has an internal lead-out channel to guide the transducer signal line to the three blind outlets in the center of the rectifier tube. Therefore, except for the upper and lower support columns, a plastic outer tube thickness of 1.8mm is sufficient to meet the strength requirements. Thus, after the improvement of the DN15 diameter outer tube structure, the minimum gap in the center of the irregularly shaped transducer 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 CN208223575 U, it not only saves materials, but also fully meets the requirement of impurities passing through smoothly.

[0045] The instrument circuit box is located outside the equal-diameter metal outer tube and consists of a lower instrument circuit box shell and an upper instrument circuit box shell. Inside the instrument circuit box are an integrator circuit board, a display screen, and a battery. The lower instrument circuit box shell mates with the outer cylinder of the transducer lead wire fixing seat, and a sealing ring seals between them. The lower instrument circuit box shell is secured by a lead wire fixing nut. Specifically, the outer ring of the transducer lead wire fixing seat also has symmetrical positioning post structures that mate with the lower instrument circuit box shell, preventing it from rotating and ensuring a very secure fit. The positioning posts are located on both sides of the outer ring of the transducer lead wire fixing seat, and their function is to fix the lower instrument circuit box shell, preventing its rotation, thereby allowing adjustment of the display direction of the instrument display screen.

[0046] The lead wire fixing cap has two functions: first, it presses the transducer lead wire fixing head by applying force to the elastic washer; second, it is used to press the lower shell of the instrument circuit box. In this way, the fixing of the lower shell of the instrument circuit box is completed in a very simple way, saving fixing components; waterproof glue is potted inside the instrument circuit box to achieve IP68 protection level.

[0047] In this invention, if the heat energy carried by the fluid is to be measured, a temperature sensor needs to be installed. Since the overall structure of the inner liner tube of the double-beam transducer composed of the irregular transducer and the rectifier tube does not require a waterproof seal between the inner side of the equal-diameter metal outer tube, when performing heat metering applications, a temperature sensor mounting base is installed by laser welding near the outlet on the outer side of the equal-diameter metal outer tube. The temperature sensor is installed in the temperature sensor mounting base, and the temperature sensor measuring rod is obliquely inserted into the outside of the transducer guide cover at the outlet, which does not affect the measurement of the fluid.

[0048] In summary, compared with the prior art, the present invention has outstanding substantial improvements and significant progress, specifically manifested in the following ways: First, for a given length of DN15 or small-diameter ultrasonic water meter base, this invention, by setting a waterproof and sealed lead-out channel structure for the signal lead-out line of the built-in irregularly shaped transducer, leads the transducer signal line out from the middle of the rectifier tube. This allows the two built-in irregularly shaped transducer structural components to be placed close to the two ends of the inner side of the equal-diameter metal outer tube, without needing to reduce the diameter of the flow meter's straight-through pipeline by using a large-to-small connector to convert the thread. This ensures that the minimum water flow gap within the DN15-diameter irregularly shaped transducer is greater than 3mm, facilitating the safe passage of impurities in the water. Consequently, the distance between the two transducer emitting surfaces reaches its maximum value, i.e., the sound path is maximized. Thus, the DN15-diameter or small-diameter ultrasonic flow meter achieves maximum range ratio and minimum starting flow.

[0049] Secondly, a transducer signal line lead-out channel is set from the support column on the irregular transducer structure to the blind hole three in the middle of the outer side of the rectifier tube. This channel can lead the transducer signal line from inside the irregular transducer through the outgoing oblique hole and the lead-out channel to the blind hole three in the middle of the rectifier tube. Therefore, the transducer signal line can be welded and led out from the transducer lead-out fixing seat.

[0050] The beneficial effects achieved are as follows: the installation of irregularly shaped transducer structural components does not need to consider the impact on the lead-out and sealing of transducer signal lines, and can be installed close to the inner side of both ends of the uniform diameter metal outer tube; therefore, it can further increase the distance between the two transducer emitting surfaces, that is, increase the sound path and improve the range ratio R.

[0051] Third, since the cross-sectional area for fluid passage is minimized in the middle 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 is to reduce obstruction, increase the cross-sectional area for water passage, and reduce pressure loss. In addition, the horizontal outlet hole of the inclined outlet hole is made by extending the wall thickness of the upper support column to connect with the rectifier tube. In this way, the area for obstructing the internal water passage is not increased, and the transducer signal line can be passed to the blind hole three in the middle of the outer diameter tube.

[0052] Fourth, the function of the lead-out channel and the lead-through sealing tube: Because the connection between the rectifier tube and the irregularly shaped transducer structural components at both ends is completed by adhesive bonding or laser welding at the joint, this connection method can ensure a firm and stable connection between the two, but it cannot guarantee that the internal joint is waterproof. By installing the lead-through sealing tube and its sealing ring three, the rectifier tube and the irregularly shaped transducer structural components are connected, and the lead-out channel is sealed and waterproofed. Therefore, after the lead-out oblique hole is filled with glue for protection, the transducer signal line can be safely led out from the lead-out oblique hole to the blind hole three in the middle of the rectifier tube.

[0053] Fifth, the present invention provides a centered lead-out wire and sealing structure for a DN15 ultrasonic through-beam water meter. It only partially seals the entire structure of the inner liner tube of a pair of through-beam transducers, without using an overall sealing method for the inner liner tube. This effectively ensures that the minimum water flow gap inside the tube is greater than 3mm, which is conducive to the safe passage of impurities. This method can cleverly lead out the transducer signal wire through a dedicated channel while reducing the use of accessories, and finally send it to the water meter circuit board.

[0054] Sixth, the transducer lead wire fixing head of the present invention is positioned at a height by the positioning surface inside the transducer lead wire fixing seat. This ensures that the lower sealing ring under 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 pressing, positioning and fixing the irregular transducer structural component.

[0055] Seventh, 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 is used to press and fix the lower shell of the instrument circuit box, reducing the number of fixing components.

[0056] Eighth, 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 with the assistance of a fixture, forming an integral structure of a double-beam transducer inner liner tube. One purpose of this structure is to ensure that the distance between the two transducer emitting surfaces is highly consistent during mass production and remains constant during flow meter assembly or use. The distance between the transducer emitting surfaces determines the range ratio, so this ensures the consistency of flow meter parameters and greatly facilitates the testing and calibration of the flow meter.

[0057] Ninth, the inner liner of the equal-diameter metal outer tube is formed by two irregularly shaped transducer structural components connected to the reduced-diameter rectifier tube, which together form an integral structure of a double-beam transducer inner liner. The positioning and fixing method is as follows: the middle of the upper side of the rectifier tube is pressed and fixed by the lead wire fixing head; the lower support columns of the transducer structural components at both ends of the lower side are positioned and fixed by two fixing bolts. Thus, the integral structure of the double-beam transducer inner liner has three positioning and fixing points, which is very firm.

[0058] Tenth, the overall length of the inner liner tube 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 the outer pipe and installing the water meter fitting, the squeezing force of the sealing gasket is mainly borne by the mating metal pipe opening. This can effectively protect the inner liner tube, so that it is subjected to less stress and does not deform during long-term use.

[0059] Eleventh, the centered lead wire and sealing structure of the DN15 ultrasonic through-beam water meter described in this invention facilitates the welding of a temperature sensor mounting base to the outside of the outlet of a metal outer pipe of equal diameter, thereby installing the temperature sensor and facilitating heat energy measurement.

[0060] This application proposes a method for installing a non-circular transducer inside a uniform-diameter metal outer tube, with a lead-out channel, a lead-out sealing tube, and a sealing structure in the middle; for clamping, positioning, and fixing the rectifier tube using a transducer lead-out fixing head; for bonding or laser welding the non-circular transducer and the rectifier tube together; and for connecting the lower shell of the instrument circuit box to the uniform-diameter metal outer tube. These methods are proposed based on years of engineering research and practical experience, and have been verified to be effective in practice. They are novel, creative, and practical. Attached Figure Description

[0061] Figure 1 This is a cross-sectional view of the center lead-out wire and sealing structure of a DN15 ultrasonic through-beam water meter. Figure 2 This is a partial sectional view of the center lead-out wire and sealing structure of a DN15 ultrasonic through-beam water meter. Figure 3 This is a side sectional view of the lead wire structure of a DN15 diameter through-beam ultrasonic water meter. Figure 4This is a side view of a DN15 diameter through-beam ultrasonic water meter. Figure 5 This is a schematic diagram of the signal line lead-out hole and instrument housing positioning structure of a DN15 through-beam ultrasonic water meter. Figure 6 This is a schematic diagram of the installation structure of a DN15 diameter through-beam ultrasonic water meter temperature sensor. In the picture: 11. Equal-diameter metal outer tube; 111. External thread; 12. Transducer lead wire fixing seat; 121. Sealing ring one; 122. Positioning surface; 123. Positioning post; 14. Transducer lead wire fixing head; 141. Lower sealing ring; 142. Side sealing ring; 13. Center hole PCB; 131. PCB positive electrode pad; 132. PCB ground pad; 15. Elastic washer; 16. Lead wire fixing cap; 25. Ceramic plate assembly; 22. Irregularly shaped transducer structural component; 221. Upper support post; 222. Lower support post; 223. Outlet oblique hole; 23. Transducer flow guide cover; 231. Flow guide cover lower groove; 26. Fixing bolt; 262. Fixing bolt rod; 261. External thread nut; 263. Spring; 112. Blind hole one; 224. Blind hole two; 225. Length; 33. Rectifier tube; 331. Sealing ring two; 332. Lead wire channel; 334. Joint; 333. Blind hole three; 44. Wire sealing tube; 441. Sealing ring three; 55. Instrument circuit box; 55A. Instrument circuit box lower shell; 55B. Instrument circuit box upper shell; 551. Integrator circuit board; 552. Display screen; 553. Battery; 18. Transducer signal line; 17. Temperature sensor mounting bracket; 171. Temperature sensor; Detailed Implementation Example 1

[0062] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0063] As attached Figure 1As shown, this embodiment is a central lead-out wire and sealing structure for a DN15 ultrasonic through-beam hot water meter. The technical application scheme is as follows: the equal-diameter metal outer tube 11 of the ultrasonic hot water meter is a 2.5mm thick stainless steel 304 tube, which is connected to the transducer lead-out wire fixing seat 12 and temperature sensor fixing seat 17 on its outer side by laser welding; irregularly shaped transducers are installed at both ends inside the equal-diameter metal outer tube, each consisting of an irregularly shaped transducer structural component 22 and a transducer flow guide cover 23; the two irregularly shaped transducer structural components 22 and the intermediate rectifier tube 33 are connected at the joint by adhesive bonding or laser welding to form a double through-beam transducer inner liner tube integral structure; (This is consistent with patent authorization announcement number CN 211317425). Unlike U, a lead-out channel 332 is provided to allow the transducer signal line to be led out from the middle of the uniform diameter metal outer tube. In the lead-out channel 332, a wire sealing tube 44 and a sealing ring 441 are installed, thereby solving the problem of sealing the lead-out channel 332 of the transducer signal line between the irregular transducer structural component 22 and the rectifier tube 33. Therefore, this substantial change, under a given straight pipe length of the ultrasonic water meter, can achieve a minimum water passage gap of >3mm in the flow channel for a DN15 diameter water meter. Thus, it not only achieves a stable maximum spacing between the two transducer emitting surfaces, i.e., improves the range ratio R, but also facilitates assembly and convenient lead-out of the transducer signal line.

[0064] The equal-diameter metal outer tube 11 is a 2.5mm thick stainless steel 304 tube with external threads 111 on both ends. On the outside of the equal-diameter metal outer tube, the transducer lead wire fixing seat 12 and the temperature sensor fixing seat 17 are connected by laser welding.

[0065] The irregularly shaped transducer consists of an irregularly shaped transducer structural component 22 and a transducer flow guide cover 23. A ceramic plate assembly 25 is encapsulated in the blind hole 224 in the middle of the irregularly shaped transducer structural component. The middle of the irregularly shaped transducer structural component and the inner side of the outer ring are connected by an upper support column 221 and a lower support column 222, respectively. A fixing bolt 26 is installed in the lower support column 222 of the transducer. The fixing bolt is positioned by a blind hole 112. The inner hole of the upper support column is a wire outlet oblique hole 223, one end of which communicates with the inside of the irregularly shaped transducer and the other end communicates with the lead wire channel 332. Through the lead wire channel 332, the transducer signal line (18) is connected to the blind hole 333 in the center outside the rectifier tube (33) and soldered to the PCB in the middle hole. 13; After the entire structure of the inner liner tube of the dual-beam transducer is installed in the metal outer tube of equal diameter, the transducer signal line leads are soldered to the PCB 13 at the center hole of the blind hole 333 through the center hole of the transducer lead wire fixing seat 12, so that the transducer signal line 18 is led out to the circuit board 551.

[0066] Since the transducer signal lines can be soldered and led out through the outgoing oblique hole 223 and the lead-out channel 332 to the rectifier tube blind hole 333 on the PCB 13, the irregularly shaped transducer structural component 22 can be installed close to the inner sides of both ends of the uniform-diameter metal outer tube 11. Therefore, this transducer signal line lead-out method can maximize the distance between the two transducer emitting surfaces, achieving its maximum value and obtaining a large range ratio R.

[0067] As attached Figure 4 As shown, since the water flow gap and fluid passage cross-sectional area are minimized in the middle part of the irregularly shaped transducer structure 22 where the transducer is located, the middle part of the irregularly shaped transducer structure 22 described in this application is connected to the inner side of the outer ring by two support columns, upper support column 221 and lower support column 222, instead of multiple columns. The purpose is to increase the water passage cross-sectional area and reduce pressure loss. In addition, the horizontal cable outlet hole of the cable outlet oblique hole 223 is to extend the thickness of the upper support column to connect with the rectifier tube. In this way, the internal water blocking area is not increased, and the transducer signal line can be led out to the blind hole 333 in the middle of the outer side of the rectifier tube.

[0068] The transducer lead wire fixing seat 12 is located at the middle of the outer side of the equal-diameter metal outer tube 11; the transducer lead wire fixing seat 12 and the equal-diameter metal outer tube 11 are connected by laser welding; the transducer lead wire fixing head 14 is located in the lower part of the transducer lead wire fixing seat 12, and has a side sealing ring 142 on the side to seal the inner side of the transducer lead wire fixing seat 12; there is a lower sealing ring 141 below for sealing the irregular transducer structural component 22; the positioning surface 122 in the transducer lead wire fixing seat is used for height positioning to ensure the height and flatness of the lead wire fixing head 14. It not only ensures that the lower sealing ring 141 below the transducer lead wire fixing head 14 has a reasonable amount of compression, but also allows the lower part of the transducer lead wire fixing head to be embedded into the interior of the rectifier tube 33, which plays the role of pressing, positioning and fixing the rectifier tube.

[0069] The elastic washer 15 is located above the transducer lead wire fixing head 14 and below the lead wire fixing cap 16. The lead wire fixing cap 16 presses and fixes the transducer lead wire fixing head 14 by applying force to the elastic washer 15.

[0070] The connection between the rectifier tube 33 and the irregularly shaped transducer structural components 22 at both ends: except for the position corresponding to the lead wire channel, the other mating surfaces are tightly connected by the convex and concave joints 334, which can make the components fit tightly and stably; during the mating, in order to waterproof and seal the lead wire between the two, the lead wire sealing tube 44 and its sealing ring 441 should be inserted first at the lead wire channel mating point, and then the two should be closed and mated; at the mating joint 334, they are connected by adhesive or laser welding to form a double-beam transducer inner liner tube integral structure.

[0071] The overall structure of the inner liner tube of the dual-beam transducer is positioned and fixed as follows: at the blind hole 333 in the middle of the outer side of the rectifier tube, the transducer lead wire fixing head 14 is used to press and fix it; inside the lower support column 222 of the transducer structure, the fixing bolt 26 is used to position and fix it; thus, the overall structure of the inner liner tube of the dual-beam transducer forms three positioning and fixing points inside the equal-diameter metal outer tube 11, which is very firm.

[0072] The fixing bolt 26 is located in the lower support column 222 of the transducer and consists of an external threaded nut 261, a fixing bolt rod 262, and a spring 263. The inner hole of the external threaded nut 261 is a hexagonal hole for easy installation. Its positioning is achieved by the fixing bolt rod 262 being inserted into the corresponding blind hole 112 inside the metal outer tube 11 of the same diameter. Installation of the fixing bolt 26: Insert the fixing bolt assembly, namely the spring 263 and the fixing bolt rod 262, into the blind hole of the lower support column 222 of the irregular transducer structural component 22, and tighten the external threaded nut 261 to fix it in place with the internal thread of the blind hole.

[0073] The length of the inner liner tube of the dual-beam transducer is 225 mm shorter than that of the equal-diameter outer metal tube 11 by 0.3 mm on each side. Its function is to ensure that the pressure of the sealing gasket is mainly borne by the mating metal tube ends when installing the water meter union. This can effectively protect the inner liner tube and prevent it from deforming due to less stress during long-term use.

[0074] A ceramic plate assembly 25 is encapsulated in the blind hole 224 in the middle of the irregularly shaped transducer structure to form a transducer. After encapsulating the ceramic plate assembly, the transducer signal line 18 is soldered. At this time, the transducer guide cover 23 is not installed yet. Instead, the transducer signal line 18 is sent through the outgoing oblique hole 223 and the lead-out channel 332 to the blind hole 333 in the middle of the rectifier tube and soldered to the PCB 13 with the center hole. The specific operation process of leading the transducer signal line 18 to the blind hole 333 in the middle of the rectifier tube 33 is as follows: The lead-out channel 332 is set inside the support column 22 on the irregularly shaped transducer structure 22 and the tube wall of the rectifier tube 33. The specifications of a single signal line are: 12 copper wires with a diameter of 0.08mm inside and a sheath with a diameter of 0.6mm outside. The PTFE wire has a smooth and hard surface and is resistant to high temperatures. For a welded double-beam transducer liner, two signal wires, a single positive signal wire and a single negative signal wire, are inserted from the middle of the transducer into the outgoing oblique hole 223. At the other end of the outgoing oblique hole 223, a tool is used to guide the wire end from the inlet of the lead-out channel 332. The wire is then pushed through the transducer opening and sent into the blind hole 333 in the middle of the rectifier tube 33. Because the surface of the wire is hard and smooth, this wire feeding process is easily completed. Figure 5As shown, the central hole PCB 13 is located at the bottom of blind hole 333 and is tightly mated with the edge of blind hole 333. The central hole PCB 13 is located at the outlet of the lead-out channel 332, and its edge has a notch to facilitate the lead-out of the transducer signal line 18 to the front of the central hole PCB 13 for soldering. After the transducer signal line is soldered, the transducer guide cover 23 is fastened, completing the process of leading the transducer signal line 18 from the inner liner tube of the double-beam transducer to the blind hole 333 in the middle of the rectifier tube 33. In order to achieve IP68 waterproofing, a flat-head thin tube is used to inject two-component A and B waterproof curing adhesive into the interior of the irregular transducer through the lead-out oblique hole 223. Note: the interior, including the outlet of the lead-out oblique hole 223, should be completely filled. In this way, the interior of the irregular transducer structure, including the lead-out channel, and the transducer guide cover are tightly integrated, so that the lead-out channel 332 achieves a waterproof sealing effect.

[0075] The function of the lead-out channel 332 and the lead-out sealing tube 44 is as follows: Since the connection between the rectifier tube 33 and the irregularly shaped transducer structural components 22 at both ends is completed by adhesive bonding or laser welding at the joint 334, this connection method can ensure a firm and stable connection between the two, but it cannot guarantee that the joint 334 is waterproof. Therefore, the lead-out sealing tube 44 and the sealing ring 441 on it serve to seal and allow the transducer signal line to pass through from the lead-out oblique hole 223 to the lead-out channel 332.

[0076] The installation sequence for inserting the complete structure of the inner liner tubes of a pair of through-beam transducers into the equal-diameter outer metal tube 11 is as follows: Press down the fixing rod 262 to retract it into the lower support column 222, insert one end of the complete structure of the inner liner tubes of a pair of through-beam transducers into the interior of the equal-diameter outer metal tube 11, and note that it should be staggered from the position of the blind hole 112 on the inner side of the equal-diameter outer metal tube 11. That is, do not let the fixing rod 262 on one side spring into the blind hole 112 first. After pressing down the other end of the fixing rod 262 and inserting the complete structure of the inner liner tubes of a pair of through-beam transducers into the equal-diameter outer metal tube 11, use a tool to hold the upper support column and the lower support column and rotate them so that the two fixing rods 262 simultaneously enter their respective blind holes 112, thus completing the assembly and fixing.

[0077] Overall transducer signal line lead-out: After completing the above procedures, the transducer signal line is led out through the center hole of the transducer lead-out cable fixing seat 12, as shown in the attached diagram. Figure 5 As shown, three leads are soldered onto the center hole of PCB 13 in blind via 3.

[0078] The wall thickness of the uniform-diameter metal outer tube 11 is sufficient to allow for direct machining of external thread 111 interfaces at both ends of the DN15 diameter tube body. A metal tube with a wall thickness of 2.5mm and an external thread height of 1.2mm is selected. While this type of metal tube is slightly thicker, its advantage lies in ease of processing and its ability to meet the technical requirement of a minimum gap >3mm in the middle of the irregularly shaped transducer, allowing impurities to pass through smoothly. The outer tube of the irregularly shaped transducer structural component 22 does not have a sealing structure but instead has an internal lead-out channel 332 to guide the transducer signal line 18 to the blind hole 333 outlet end in the middle of the rectifier tube 33. Therefore, except for the upper support column 221 and the lower support column 222, the remaining plastic outer tube thickness of 1.8mm fully meets the strength requirements. Thus, after the improvement of the DN15 diameter outer tube structure, the minimum gap in the middle of the irregularly shaped transducer 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 CN208223575 U, it not only saves materials, but also fully meets the requirement of impurities passing through smoothly.

[0079] The instrument circuit box 55 is located outside the equal-diameter metal outer tube 11 and consists of a lower instrument circuit box 55A and an upper instrument circuit box 55B. The instrument circuit box 55 contains an integrator circuit board 551, a display screen 552, and a battery 553. The lower instrument circuit box 55A mates with the outer cylinder of the transducer lead wire fixing seat 12, and a sealing ring 121 seals between them. The lower instrument circuit box 55A is pressed and fixed by the lead wire fixing nut 16. Specifically, the outer ring of the transducer lead wire fixing seat 12 is also provided with symmetrical positioning posts 123 that cooperate with and position the lower instrument circuit box 55A. The positioning posts 123 are located on both sides of the outer ring of the transducer lead wire fixing seat 12, and their function is to fix the lower instrument circuit box 55A and prevent it from rotating, thereby allowing adjustment of the display direction of the instrument display screen 552.

[0080] The lead wire fixing cap 16 has two functions: first, it presses the transducer lead wire fixing head by applying force to the elastic washer 15; second, it is used to press the lower shell 55A of the instrument circuit box. In this way, the fixing of the lower shell 55A of the instrument circuit box is completed by a very simple method, saving fixing components; waterproof glue is potted inside the instrument circuit box 55 to achieve IP68 protection level.

[0081] In this embodiment, if the heat energy carried by the fluid is to be measured, a temperature sensor 171 needs to be installed. Since the overall structure of the inner liner of the double-beam transducer composed of the irregular transducer and the rectifier tube 33 does not require a waterproof seal between the inner side of the equal-diameter metal outer tube 11, when performing heat metering applications, the temperature sensor mounting base 17 is laser-welded to the outer side of the equal-diameter metal outer tube near the outlet. The temperature sensor 171 is installed in the temperature sensor mounting base 17, and the temperature sensor measuring rod is obliquely inserted into the outer side of the transducer guide cover 23 at the outlet, which does not affect the measurement of the fluid.

[0082] The above embodiments illustrate the application of the centered lead wire and sealing structure of a DN15 ultrasonic through-beam water meter in the heat energy metering of hot water. However, the present invention is not limited to the specific embodiments described above. Any modifications or variations made based on the content of the present invention shall fall within the scope of protection claimed by the present invention.

Claims

1. A DN15 ultrasonic through-beam water meter, characterized in that: The system includes a constant-diameter metal outer tube (11), a shaped transducer, a shaped transducer structural component (22), a rectifier tube (33), a lead-out channel (332), a lead-out sealing tube (44), a sealing ring three (441), a transducer lead-out fixing seat (12), a transducer lead-out fixing head (14), a lead-out fixing cap (16), an instrument circuit box (55), and a temperature sensor fixing seat (17). The constant-diameter metal outer tube (11) has external threads (111) at both ends on its outer side, and the transducer lead-out fixing seat (12) and the temperature sensor fixing seat (17) are welded to its outer middle and outer water outlet ends, respectively. The shaped transducer structural component (22) is connected to the inner side of the outer ring by an upper support column (2). 21) and the lower support column (222) are connected; the irregular transducer is assembled by adhesive bonding between the irregular transducer structural component (22) and the transducer guide cover (23), and is installed at both ends of the inner side of the equal diameter metal outer tube (11); the rectifier tube (33) and the irregular transducers at both ends are connected by adhesive bonding or laser welding to form a double-beam transducer inner liner tube integral structure; the transducer lead wire fixing head (14) is located at the lower end inside the transducer lead wire fixing seat (12), and there is a side sealing ring (142) on the side to seal the inner side of the transducer lead wire fixing seat (12); there is a lower sealing ring (141) below for sealing the irregular transducer structural component (22); by the transducer The positioning surface (122) inside the lead wire fixing seat is used for height positioning to ensure the height and flatness of the transducer lead wire fixing head (14). It not only ensures that the lower sealing ring (141) under the transducer lead wire fixing head (14) has a reasonable amount of compression, but also embeds the lower part of the transducer lead wire fixing head into the interior of the rectifier tube (33), which plays the role of pressing, positioning and fixing the rectifier tube (33); the ceramic plate assembly (25) is encapsulated in the blind hole two (224) in the middle of the irregular transducer structural component (22); the middle part of the irregular transducer structural component (22) and the inner side of the outer ring are connected by the upper support column (221) and the lower support column (222) respectively; the transducer lower support column (222) is installed inside The device is equipped with a fixing bolt (26); the fixing bolt is positioned by a blind hole (112); the inner hole of the upper support column (221) is a wire outlet oblique hole (223), one end of which is connected to the inside of the irregular transducer and the other end is connected to the lead wire channel (332). Through the lead wire channel (332), the transducer signal line (18) is connected to the blind hole three (333) on the outside of the rectifier tube (33) and soldered to the center hole PCB (13); in the lead wire channel (332), a wire sealing tube (44) and a sealing ring three (441) are installed to connect and seal the lead wire channel (332) between the irregular transducer structural component (22) and the rectifier tube (33); the minimum water passage gap in the flow channel is greater than 3mm.

2. The DN15 ultrasonic through-beam water meter according to claim 1, characterized in that: The routing channel of the transducer signal line (18) is as follows: the transducer signal line (18) starts from the blind hole two (224) inside the irregular transducer, passes through the outgoing oblique hole (223), the wire sealing tube (44), and the lead-out channel (332), and reaches the central hole PCB (13) inside the central blind hole three (333) outside the rectifier tube (33), and is soldered to the central hole PCB (13); by soldering the transducer signal lines of the two irregular transducers on the central hole PCB (13), the output is connected to the totalizing circuit board (551).

3. The DN15 ultrasonic through-beam water meter according to claim 1, characterized in that: The connection between the rectifier tube (33) and the transducer structural components (22) at both ends is as follows: except for the position corresponding to the lead-out channel (332), the mating surfaces of the other joints (334) are connected by convex and concave inlay; at the mating point of the lead-out channel (332), the lead-out sealing tube (44) and its sealing ring three (441) are used to close and mate the rectifier tube (33) and the transducer structural component (22); at the joint (334), the connection is made by adhesive bonding or laser welding to form a double-beam transducer inner liner tube integral structure.

4. The DN15 ultrasonic through-beam water meter according to claim 3, characterized in that: The positioning and fixing method of the inner liner tube of the dual-beam transducer is as follows: the rectifier tube (33) is pressed and fixed by the lead wire fixing head (14) at the center blind hole three (333) on the outside of the rectifier tube (33); the lower two ends are positioned and fixed by two fixing bolts (26) extending into the blind hole one (112) in the lower support column (222) of the transducer structure; for the inner liner tube of the dual-beam transducer, three positioning and fixing points are formed in the equal diameter metal outer tube (11).

5. The DN15 ultrasonic through-beam water meter according to claim 4, characterized in that: The overall length (225) of the inner liner of the dual-beam transducer is 0.3 mm shorter on each side than the length of the equal-diameter outer metal tube (11).

6. The DN15 ultrasonic through-beam water meter according to claim 4, characterized in that: Installation of the double-beam transducer inner liner tube integral structure inserted into the equal-diameter metal outer tube (11): Press down the fixing rod (262) to retract its head, insert one end of the double-beam transducer inner liner tube integral structure into the metal outer tube (11), the fixing rod (262) should be offset from the position of the blind hole one (112) on the inner side of the equal-diameter metal outer tube (11), press down the other end of the fixing rod (262), insert the entire double-beam transducer inner liner tube integral structure into the equal-diameter metal outer tube (11), rotate the double-beam transducer inner liner tube integral structure by clamping the upper support column (221) and the lower support column (222), so that the two fixing rods (262) at both ends simultaneously enter their respective blind holes one (112), and complete the installation and fixing.

7. The DN15 ultrasonic through-beam 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 instrument circuit box (55) contains an integrator circuit board (551), a display screen (552), and a battery (553). The lower shell (55A) of the instrument circuit box is fitted with the outer cylinder of the transducer lead wire fixing seat (12), and the two are sealed by a sealing ring (121). The lower shell (55A) of the instrument circuit box is pressed and fixed by the lead wire fixing cap (16). The outer cylinder of the transducer lead wire fixing seat (12) is also provided with two symmetrical positioning posts (123), which are fitted and positioned with the lower shell (55A) of the instrument circuit box. The lead wire fixing cap (16) has two functions: first, it presses the transducer lead wire fixing head (14) by applying force to the elastic washer (15); second, it is used to press the lower shell (55A) of the instrument circuit box.

8. The DN15 ultrasonic through-beam water meter according to claim 1, characterized in that: The temperature sensor mounting base (17) is located outside the equal-diameter metal outer tube (11) near the water outlet, and the temperature sensor (171) is installed inside the temperature sensor mounting base (17).

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