A fixed pair of ultrasonic water meter suitable for DN15 caliber transducer stand

Abstract

This invention belongs to the technical field of flow metering equipment, specifically a through-beam ultrasonic water meter with a DN15 diameter transducer column fixed. It aims to address the shortcomings of existing through-beam ultrasonic DN15 diameter water meters, such as insufficient water flow gap within the pipe, low metering range ratio due to the use of variable diameter adapters, and the gap between the current technology and the six principles of optimal solutions for ultrasonic water meter technology development. By installing transducer fixing columns at both ends of the flow meter's outer pipe and positioning these columns in terms of height and direction, a double through-beam transducer is formed within the flow meter's outer pipe. The base pipe is manufactured using an integrated brass / stainless steel forging / casting process, ensuring a minimum water flow gap greater than 3mm to facilitate impurity passage. Within a given straight pipe length, this invention maximizes the metering range ratio, minimizes the starting flow rate, provides high measurement accuracy, and ensures high consistency in mass production.

Description

Technical Field

[0001] This invention belongs to the technical field of ultrasonic flow metering equipment, and specifically relates to a column-fixed through-beam ultrasonic water meter adapted to a DN15 diameter transducer. 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, the most widely used all-electronic flow metering devices worldwide are electromagnetic flow meters and the emerging ultrasonic flow meters.

[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, which currently have a resolution 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 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 changes in the measured volume (for which electromagnetic flow meters require the installation of a thermometer), larger diameter multi-channel for higher accuracy and safety (electromagnetic flow meters only have a pair of coils and corresponding electrodes, and must be scrapped 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 the technological development direction and principles for upgrading and improving ultrasonic water meters be defined? 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:

[0007] (1) Principle of maximizing sound path: In order to make the ultrasonic water meter have a large range ratio, for ultrasonic water meters, especially the most commonly used DN15 diameter, the sound path between ultrasonic transducers should be maximized. Because for water meters, the large range ratio is an extremely important indicator for trade settlement and is also the most important technical indicator of water meters. To make the ultrasonic water meter have a large range ratio, the projection distance of the line connecting the two transducers of the ultrasonic water meter in the direction of water flow in the main pipe 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.)

[0008] Based on theoretical analysis, the following conclusions can be drawn regarding the metering quality of ultrasonic flow meters:

[0009] 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%).

[0010] 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 overall zero drift generated by the ultrasonic flowmeter circuit and transducer, as well as the water resistance design of the flowmeter pipeline). Therefore, it can be derived that for a certain 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 is:

[0011]

[0012] 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 corresponding flow meter pipeline. 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, β is a known quantity related to the measurement time difference and sound velocity of the flow meter, let β= V3 / 10k be a constant, and V1 is calculated by 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:

[0013] 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.

[0014] (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.

[0015] (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 two transducer emitting surfaces 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 in the later stage;

[0016] (4) Pipe body sealing safety principle: In order to ensure sealing safety, try not to use the whole sealing method but the partial sealing method to ensure the reliability and durability of the sealing.

[0017] (5) Adaptability principle: Small diameter makes it easy to install temperature sensors to meet the needs of heat metering;

[0018] (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 ensures that the flow meter has a high degree of consistency.

[0019] 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.

[0020] 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.

[0021] According to the standards of the above principles, existing technologies still have technical defects or deficiencies.

[0022] 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 Φ17 at the front and Φ21 at the rear), 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.

[0023] Patent publication number CN 201716054 U discloses another transducer-to-beam mode, in which the transducer extends from the side of the pipe. Through-beam ultrasonic flow meters require that the two opposing surfaces of the transducer be strictly parallel. However, this method of fixing the transducer with a single insertion hole and no support below, and sealing and positioning it by pressing the lower sealing ring with the transducer's raised 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 becomes 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 opposing surfaces of the transducer will not remain parallel. Experiments show that for plane waves, the acoustic 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.

[0024] 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 165mm. If this mode is applied to a DN15 diameter pipe, the sealing and lead-out wire methods specified in the patent necessitate 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 reducing connection as described in patent publication number CN 208223575 U to achieve the DN15 specification. This threaded reducing 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.

[0025] Patent publication number CN 205317274 U provides another transducer column fixed through-beam mode. In this mode, the top of the transducer column is positioned and fixed, and the bottom of the column is also fixed in the groove at the bottom of the pipe, making the positions of the two transducers and their through-beam surfaces stable and reliable. However, this patent does not provide clear and specific methodological details regarding the structure of the columnar transducer and its specific implementation, making it unusable for implementers and thus lacking practicality.

[0026] 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.

[0027] Regarding the specifications of ceramic transducers for ultrasonic transducers, the Water Meter Committee of the China Metrology Association sets the following limits on transducer application standards:

[0028] The specified vibration frequencies of the transducer ceramic plates are: 1MHz, 2MHz, and 4MHz.

[0029] Common diameter-to-thickness ratios for ceramic sheets are: Φ12 / 2mm; Φ8 / 1mm; Φ8 / 0.5mm;

[0030] The wavelengths corresponding to various frequencies for a certain material are: 2.5mm, 1.25mm, 0.625mm.

[0031] (Assume the speed of sound in a certain sound-conducting material at room temperature is 2500 m / s)

[0032] 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.

[0033] 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.

[0034] Patent CN 211317425 U is a transducer-in-place solution that maximizes the distance between two transducers and is well-suited for diameters of DN20 and above. However, typically, for DN15 water flow meters, if the transducer is to be placed inside the pipe, the minimum gap between the transducer and the water flow must be ≥3mm to ensure that impurities in the water can pass through smoothly.

[0035] Analysis of the implementation of this patent shows that if it is applied to a DN15 water meter, i.e., using an internal transducer, where the transducer (i.e., the flow meter tube) is integrated and 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 the minimum clearance for water flow can be calculated:

[0036] 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).

[0037] Therefore, the flow gap of the fluid passing through the transducer inside the pipe can be calculated as follows:

[0038] (26.44mm-2×3.2mm-2×2.5mm-10mm) / 2=5.04mm / 2=2.52mm≤3mm.

[0039] 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 method violates the principle of maximizing sound path, and the water meter's range ratio R is significantly reduced.

[0040] 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).

[0041] In summary, 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, there is still a lack of effective solutions. Summary of the Invention

[0042] 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 installation and fixing structure of the transducer, the sealing method of the transducer, the lead-out method of the transducer, and the fixing installation method of the totalizing circuit box and the flow meter base in small-diameter ultrasonic water meters. This will achieve a simple structure and be safe and reliable, while ensuring a loud sound range and a large water flow gap.

[0043] It is evident that for an ultrasonic water meter with a length of 165mm and a DN15 diameter, if it is possible to install a through-beam transducer while ensuring a minimum water 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 will be approximately 105mm. This distance will be significantly greater than the 63mm distance when an adapter is used. As can be seen, after the improvement, the range ratio increases by approximately 105 / 63 = 167%, achieving a qualitative leap. Furthermore, by appropriately reducing the diameter of the flow meter's middle section (while meeting pressure loss requirements), the range ratio of the DN15 water meter can be further effectively improved, the flow stability increased, and the starting flow rate reduced (this solution has been tested and can achieve a starting flow rate Q). q <0.5L / h).

[0044] This invention provides a transducer-post-fixed through-beam ultrasonic water meter suitable for DN15 diameter. The technical solution can be described as follows: the ultrasonic base tube is manufactured using an integrated forging / casting process with brass and stainless steel. The transducer is fixed on a transducer fixing column, which has upper and lower height and directional positioning. The water flow gap between the transducer and the inner side of the tube is greater than 3mm to facilitate the passage of impurities. For a given straight pipe length in the ultrasonic water meter, and for the most common household DN15 diameter, this avoids the use of cumbersome large-diameter to small-diameter conversion joints. Using a single integral pipe section ensures that the two transducer emitting surfaces remain parallel and have a long sound path, resulting in a smaller starting flow rate and a larger range ratio.

[0045] This invention relates to a DN15 diameter transducer column-fixed through-beam ultrasonic water meter, characterized by: an outer tube body of the flowmeter, a transducer and its fixing column, upper and lower positioning and sealing structures for the fixing column, and a connection structure between the lower shell of the totalizing circuit box and the flowmeter base. The outer tube body is connected to an external pipeline for the flow rate to be measured via pipe threads at both ends. The ultrasonic transducer is mounted on the fixing columns at both ends of the outer tube body, thus forming a double through-beam transducer within the outer tube body. An inner lining rectifier tube is embedded in the inner wall of the middle region of the outer tube body. Because the metal outer tube body is forged / cast, it is easy to adjust the local diameter within the tube, making it easy to achieve a larger local inner diameter and ensuring a minimum water passage gap greater than 3mm, facilitating the passage of common impurities. Furthermore, since both the fixing column and the inner lining rectifier tube are injection molded using precision molds, their consistency ensures the consistency of the flowmeter base during mass production, facilitating the testing and calibration of the flowmeter. Therefore, given the length of the straight pipe of the ultrasonic water meter, this invention achieves the goals of maximizing the range ratio and minimizing the starting flow rate for DN15 diameter metering.

[0046] The flow meter base is a metal outer tube with threads at both ends. The outer tube has a transducer post mounting base and a lower positioning groove for the transducer post. The overall transducer fixing structure consists of a transducer fixing post and a flow guide. The transducer or transducer assembly is mounted on the transducer fixing post, and there are two mounting methods: one is to install an independent transducer in the middle hole of the transducer fixing post, where the hole is a through hole; the other is to directly encapsulate the transducer assembly in the middle hole of the transducer fixing post. Although the position is the same, the hole structure is a blind hole. The lower end of the transducer fixing post is positioned and installed on... The transducer column is positioned in a lower positioning groove, with its upper end installed in the through hole of the transducer column mounting base, and its height is positioned by a positioning platform. The upper outer ring of the transducer fixing column has a side seal and a top seal. A metal elastic washer is located above the transducer fixing column and the top sealing ring. The external thread metal cap is located above the elastic washer and is connected to the internal thread of the transducer column mounting base. The lower shell of the totalizing circuit box is fixedly connected to the lower shell fixing screw hole on the transducer column mounting base by screws. For water meter applications with high range ratio and accuracy requirements, an inner lining rectifier tube must be installed. The inner lining rectifier tube is located in the middle of the metal outer shell and is fixed by a rectifier tube fixing bolt. The outer ring of the inner lining rectifier tube has a sealing ring, which only serves to tightly fit the inner lining rectifier tube and block water.

[0047] The flow meter base is formed by integrated forging / casting of brass / stainless steel. The transducer column mounting base on the metal outer tube and the diameter-changing parts of the tube are formed by stamping / casting in one go using the same mold. The outer tube is consistent, and the internal positioning platform and positioning groove are completed by multi-hole positioning processing in one go by a special machine. This greatly improves the consistency level of mass production of flow meter bases.

[0048] The transducer mounting post is manufactured by PPS / PPT using a precision injection mold.

[0049] The transducer mounting post has transducer mounting holes, and the transducer formed in the mounting holes can be mounted and fixed in two ways. Both methods facilitate installation and allow the transducer signal lines to be led out:

[0050] The first transducer installation and fixing method is as follows: A complete transducer is installed in the through hole. The transducer is sealed by a sealing ring and positioned by a positioning platform. The lead wire is led out from the rear end of the transducer. Finally, at the rear end of the transducer, a flow guide with external threads is screwed into the internal threaded hole of the transducer fixing post to tighten the transducer. The specific operation process of this transducer and lead wire assembly method is as follows: The transducer is installed in the through hole of the transducer post. The lead wire is passed through the wire guide oblique hole and sent to the upper cavity of the transducer fixing post. Next, the transducer fixing post is inserted from the transducer post mounting hole into the positioning groove for directional positioning. The positioning groove under the transducer post is a rectangular groove. Then, the external thread of the flow guide is screwed into the internal threaded hole of the transducer fixing post to tighten the transducer. In order to better guide the fluid, the flow guide cap has a certain length, so it must be installed from the front / rear end of the tube body with a tool after the transducer fixing post is installed. After installing the flow guide cap, use a flat-headed fine needle to inject two-component A and B high-strength adhesive into the flow guide shroud through the wire hole. Then fix the flow guide shroud to the transducer fixing post. The sealing ring on the flow guide shroud prevents leakage during adhesive injection.

[0051] The second transducer mounting method differs from the independent transducer described above in that the transducer and transducer mounting post are integrated. The transducer assembly is encapsulated in a blind hole in the center of the transducer mounting post. This is achieved by bonding a ceramic sheet to the bottom of the blind hole using two-component A and B adhesive. The ceramic sheet leads are soldered to the PCB, and the lead wires are also soldered and led out onto the PCB. In this method, the transducer lead wires are assembled by passing them through a wire-passing oblique hole to the upper cavity of the transducer mounting post. The transducer mounting post is then inserted into the transducer post mounting hole, with its lower end extending into the rectangular positioning groove below the transducer post for directional positioning. Notably, unlike the previous method, the flow guide here has no external threads, and the through hole has no internal threads. Therefore, the flow guide is simply squeezed into the blind hole of the transducer mounting post. Finally, using a flat-headed fine needle, inject two-component A and B high-strength adhesive into the flow guide through the wire hole. In particular, the sealing ring on the flow guide prevents leakage during the injection of adhesive, while the grooved barb structure at the bottom of the flow guide helps to tighten and fix the flow guide by bonding with the A and B adhesives.

[0052] Experiments show that for plane waves, the installation of a pair of through-beam transducers requires that the emitting surfaces of the two transducers be strictly parallel; even a small angular deviation will cause a significant attenuation of the received signal amplitude. Conversely, a small displacement (e.g., a 1mm misalignment) of the centerlines of the two parallel transducers has almost no attenuation of the received signal amplitude. Therefore, maintaining the parallelism of the emitting (receiving) surfaces of the two transducers is crucial. The transducer fixing post of this invention is positioned and installed at its lower end within a positioning groove under the transducer post for directional and angular positioning. This positioning groove is a rectangular blind hole. The upper end is installed in the through hole of the transducer post mounting base, and the positioning platform positions the height to ensure that the height of the pair of transducers in the flow channel is consistent. The upper outer ring of the transducer fixing post has a side sealing ring and a top sealing ring, forming a two-stage, two-method sealing system to ensure reliable sealing. The elastic gasket is located above the top sealing ring of the transducer fixing post. The external threaded cap is located above the elastic washer. By tightening the hexagonal inner hole in the center of the external threaded cap, its external thread connects with the internal thread of the transducer column mounting base, pressing the transducer fixing column tightly onto the positioning platform to determine its height.

[0053] Since the base metal outer tube is forged / cast, the local diameter between the transducer fixing post and the inner cavity of the metal outer tube can be enlarged. Therefore, the gap between the transducer fixing post and the inner cavity of the metal outer tube can easily meet the requirement of ≥3mm. In terms of processing, the outer and inner diameters of the metal tube in the transducer mounting area are relatively large, and the inner cavity is machined using an internal grooving tool, which is a conventional and extremely convenient process.

[0054] For water meter applications with high requirements for range ratio and accuracy, since they are all injection molded from engineering plastics using precision molds, the transducer fixing column and the inner lining rectifier tube have a high degree of consistency. This ensures the consistency of flow channels and performance in batch products and plays an important role in simplifying the subsequent testing and calibration of the flow meter. In heating metering applications, since the requirements for range ratio are not high (the highest value of the standard range ratio R for heating is 250), the inner lining rectifier tube does not need to be installed.

[0055] The lower shell of the totalizing circuit box is conveniently fixed to the lower shell mounting screw holes on the transducer column mounting base using screws. If IP68 waterproofing is required, the inside of the totalizing circuit box can be filled with transparent waterproof adhesive.

[0056] In this invention, if the heat energy carried by the fluid is to be measured, a temperature sensor is required. Since the integral metal outer tube is forged / cast, this straight-through, transducer column-fixed through-beam ultrasonic flowmeter structure not only facilitates the formation of the temperature sensor mounting base using molds, but also greatly facilitates temperature sensor installation because no internal sealing is required. In heat metering applications, the temperature sensor mounting base can be placed near the outlet at the outer end of the metal outer tube. The temperature sensor can be easily installed in the mounting base, with the temperature sensor's measuring rod angled outside the transducer guide cover, without affecting the measurement of the fluid.

[0057] This invention can be applied to larger diameters, such as DN40. In this case, the flow channel only has a narrowing in the middle, and the transducers can adopt a three-to-three channel mode, that is, three transducers on one side. For applications with diameters of DN50 and above, the threaded interface of the base pipe can be replaced with a flange connection.

[0058] In summary, compared with the prior art, the substantial improvements and advancements proposed in this application can be attributed to the following aspects:

[0059] First, this invention proposes a transducer-post-fixed through-beam ultrasonic water meter adapted to DN15 diameter. For a given length of DN15 or smaller diameter ultrasonic flow meter base meter, by setting up a transducer fixing post with upper and lower positioning, a transducer lead wire, and a sealing structure, the lead wire is led out through the oblique hole of the transducer fixing post. This allows two built-in transducers to be placed close to both ends of the flow meter's straight pipe, increasing the spacing between the pair of transducers. Since the metal outer tube is forged / cast, it is easy to ensure that the minimum water passage gap inside the pipe is greater than 3mm, facilitating the passage of common impurities, without requiring a large-to-small diameter adapter to reduce the diameter of the flow meter's straight pipe. Therefore, with a given length of the ultrasonic water meter's straight pipe, this invention achieves the goals of maximizing the range ratio and minimizing the starting flow for DN15 diameter metering.

[0060] Secondly, the lower end of the transducer fixing column of the present invention is positioned and installed in the rectangular blind hole groove under the transducer column for directional and angular positioning; the upper end of the transducer column is installed in the through hole of the transducer column mounting base, and the height is positioned by the positioning platform. This installation and positioning method of the transducer can ensure that the two transducer emitting surfaces are strictly parallel, overcoming the defect of slight angular deviation between the transducer emitting surfaces due to unilateral fixing of the transducer, and ensuring the amplitude strength of the received signal.

[0061] Third, the transducer mounting post of the present invention has transducer mounting holes. The transducer formed in these mounting holes can be installed and fixed in two ways, both of which facilitate installation and the lead-out of the transducer signal lines: The first method uses a complete transducer, installed in a through hole, sealed by a sealing ring, positioned by a positioning platform, and the lead-out line is led out from the rear end of the transducer through a wire-passing oblique hole. Finally, the rear end of the transducer is screwed into the internal threaded hole of the transducer mounting post by the external thread of the flow guide shroud to press and fix the transducer; The second method integrates the transducer and the transducer mounting post. That is, the transducer assembly is encapsulated in a blind hole, the transducer mounting post is inserted into the transducer post mounting seat hole, its lower end is inserted into the positioning groove under the transducer post for directional positioning, the flow guide shroud is squeezed into the through hole of the transducer mounting bracket, and then sealed with adhesive.

[0062] Fourth, for water meter applications with high requirements for range ratio and accuracy, since the components are all injection molded with engineering plastics using precision molds, the transducer fixing column and the inner lining rectifier tube have a high degree of consistency, ensuring the consistency of flow channels and performance of batch products, which plays an important role in simplifying the subsequent testing and calibration of flow meters.

[0063] Fifth, the lower shell of the totalizing circuit box described in this invention is fixedly connected to the lower shell fixing screw hole on the transducer column mounting base by screws, which is extremely convenient.

[0064] Sixth, the present invention proposes a structure for a through-beam ultrasonic water meter with a DN15 diameter transducer column fixed, which facilitates the installation of a temperature sensor and can be used for heat energy measurement.

[0065] Seventh, the structure of the present invention for a DN15 diameter transducer column fixed through-beam ultrasonic water meter has two transducer column mounting seats located at both ends of an 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.

[0066] Eighth, this invention can be applied to larger diameters, such as DN40. In this case, the flow channel only has a narrowing in the middle, and the transducers can adopt a three-to-three channel mode, that is, three transducers on one side. For applications with a diameter of DN50 and above, the threaded interface of the base pipe can be replaced with a flange connection. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of a through-beam ultrasonic water jet display adapted to a DN15 diameter transducer column fixed through-beam type.

[0068] Figure 2 This is a schematic diagram of a transducer assembly directly encapsulated in a blind hole of a transducer mounting post.

[0069] Figure 3This is a schematic diagram of the fixed installation of the temperature sensor of the through-beam ultrasonic flow meter with the transducer column fixed.

[0070] Figure 4 This is a schematic diagram of a large-diameter, multi-channel, direct-through, transducer column-fixed, through-beam ultrasonic water jet.

[0071] Figure 5 This is a schematic diagram of a large-diameter ultrasonic multi-channel transducer and its column fixing structure.

[0072] Figure 6 This is a schematic diagram of the assembly of a large-diameter multi-channel ultrasonic transducer.

[0073] In the picture:

[0074] 11. Metal outer tube body; 111. Pipe thread one; 112. Pipe thread two; 33. Transducer column mounting base; 113. Transducer column lower positioning groove; 114. Inner cavity of transducer fixing column tube; 115. Flow channel without rectifier tube; 116. Large diameter pipe inlet flow channel; 22. Transducer fixing column; 23. Flow guide; 231. Sealing ring one; 232. Barbed structure; 24. Transducer; 241. Sealing ring two; 242. Transducer assembly; 25. Elastic washer; 26. External threaded cap; 27. Fixing screw; 28. Transducer signal cable; 34. Fixing screw hole; 221. Transducer positioning platform; 222. Through hole; 2222. Blind hole; 223. Angled wire hole; 226. Lower column; 227. Upper column; 331. Positioning platform; 224. Side seal; 225. Top seal; 25. Elastic washer; 77. Instrument box; 77A. Lower shell of instrument circuit box; 77B. Upper shell of instrument circuit box; 771. Integrator circuit PCB; 772. Display screen; 773. Hole in lower shell of instrument circuit box; 774. Wire hole in lower shell of instrument circuit box; 775. Battery; 66. Inner rectifier tube liner; 661. Sealing ring three; 55. Rectifier tube fixing bolt; 551. Sealing ring four; 227. Blind hole; 44. Temperature sensor holder; 441. Temperature sensor. Detailed Implementation

[0075] The implementation of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0076] Example 1:

[0077] As attached Figure 1As shown, this embodiment is a through-beam ultrasonic water meter with a DN15 diameter transducer column fixed, including a flowmeter metal outer tube 11, a transducer 24, a transducer assembly 242 and its transducer fixing column 22, a transducer fixing column positioning platform 331, a transducer column lower positioning groove 113 and its sealing structure, an external threaded cap 26, a connection structure between the lower shell 77A of the instrument circuit box and the flowmeter base, and a temperature sensor seat 44; wherein, the two ends of the flowmeter metal outer tube 11 are connected to the external pipe to be measured through pipe thread one 111 and pipe thread two 112 respectively, and the flowmeter metal outer tube 11 contains a flowmeter metal outer tube 11. Transducer fixing posts 22 are provided at both ends for mounting ultrasonic transducers, thus forming a double-beam transducer 24 inside the outer tube of the flowmeter. An inner lining rectifier tube 66 is embedded in the central area of ​​the flowmeter's metal outer tube. Since the metal outer tube 11 is forged / cast, it is easy to adjust the local diameter inside the tube, making it easy to ensure that the minimum water passage gap inside the tube is greater than 3mm, facilitating the passage of common impurities. Furthermore, since both the transducer fixing posts 22 and the inner lining rectifier tube 66 are injection molded from precision molds, their consistency ensures the consistency of the flowmeter base during mass production, facilitating the flowmeter's testing and calibration. Therefore, given the straight-through pipe length of the ultrasonic water meter, this invention achieves the goals of maximizing the range ratio and minimizing the starting flow for DN15 diameter measurement.

[0078] The flow meter base is made of a metal outer tube 11. The metal outer tube 11 has a first pipe thread 111 and a second pipe thread 112 at both ends. The metal outer tube has a transducer post mounting base 33 and a transducer post positioning groove 113. The overall structure for fixing the transducer 24 consists of a transducer fixing post 22 and a flow guide shroud 23. The transducer 24 or transducer assembly 242 is mounted on the transducer fixing post 22. There are two mounting methods: one is to install an independent transducer 24 in the through hole 222 in the middle of the transducer fixing post; the other is to directly encapsulate the transducer assembly 242 in the blind hole 2222 in the middle of the transducer fixing post 22, as shown in the attached figure. Figure 2As shown, although the position is the same as the former, the hole structure here is a blind hole; the lower end of the transducer fixing column 22 is positioned and installed in the transducer column lower positioning groove 113, and the upper end is installed in the through hole of the transducer column mounting base 33, and the height is positioned by the positioning platform 331; the upper outer ring of the transducer fixing column 22 has a side seal 224 and a top seal 225; the elastic washer 25 is located above the transducer fixing column 22 and the top seal 225; the outer threaded cap 26 is located above the elastic washer 25, and... The transducer column mounting base 33 is internally threaded; the lower shell 77A of the instrument circuit box is fixedly connected to the lower shell fixing screw hole 34 on the transducer column mounting base 33 by fixing screw 27; for water meter applications with high range ratio and accuracy requirements, an inner lining rectifier tube 66 is added. The inner lining rectifier tube 66 is located in the middle of the metal outer tube body 11 and is fixed by the rectifier tube fixing bolt 55; the sealing ring 661 on the outer ring of the inner lining rectifier tube 66 only serves to tightly fit the inner lining rectifier tube and block water.

[0079] The flow meter base is formed by integrated forging / casting of brass / stainless steel. The transducer column mounting seat 33 on the metal outer tube 11 and the diameter change of the tube are formed by stamping / casting in one go using the same mold. The outer tube is consistent. The positioning platform 331 and the positioning groove 113 under the transducer column are completed by multi-hole positioning in one go by a special machine, which greatly improves the consistency level of the mass production of the flow meter base.

[0080] The transducer mounting post 22 is manufactured by PPS / PPT using a precision injection mold.

[0081] The transducer mounting post 22 has a transducer mounting through hole 222 or a blind hole 2222, meaning that the transducer formed in the transducer mounting hole can be mounted and fixed in two ways. Both methods facilitate installation and allow the transducer signal line 28 to be led out.

[0082] The first method for installing and fixing the transducer is as follows: (see attached image) Figure 1As shown, a complete transducer 24 is installed in the through hole 222. The transducer is sealed by a second sealing ring 241 and positioned by a transducer positioning platform 221. The transducer signal line 28 is led out from the rear end of the transducer 24. Finally, at the rear end of the transducer, a guide shroud 23 with external threads is screwed into the internal threaded hole of the transducer fixing post 22 with a tool to press the transducer 24. The specific operation process of this method is as follows: the transducer and transducer signal line are assembled by installing the transducer 24 in the through hole 222, and the transducer signal line 28 is passed through the wire guide oblique hole 223 and sent to the upper cavity of the transducer fixing post 22. Next, insert the transducer fixing post 22 into the hole of the transducer post mounting base 33, and position its lower end in the positioning groove 113 under the transducer post. Then, using a tool, screw the external thread of the flow guide shroud 23 into the internal thread of the through hole 222 of the transducer fixing post to press the transducer 24. For better fluid guidance, the flow guide shroud 23 has a certain length, so it must be installed from the front / rear end of the pipe body after the transducer fixing post 22 is installed. For this transducer installation method, the through hole 222 of the transducer fixing post is located at the end where the flow guide shroud is installed, and has several turns of internal thread. Finally, using a flat-headed fine needle, inject two-component A and B high-strength adhesive into the flow guide shroud 23 through the oblique hole 223 to fix the flow guide shroud 23 to the transducer fixing post 22. The sealing ring 231 on the flow guide shroud prevents leakage during adhesive injection.

[0083] The second method for installing and fixing the transducer is as follows: (see attached) Figure 2 As shown, unlike the independent transducers described above, the transducer and transducer mounting post 22 are integrated. The transducer assembly 242 is encapsulated within a blind hole 2222. This is achieved by bonding a ceramic sheet to the bottom of the blind hole using two-component A and B adhesive, soldering the ceramic sheet leads to the PCB, and soldering and leading out the transducer signal line 28 to the PCB. In this method, the transducer signal line is assembled by passing the transducer signal line 28 through the through-hole 223 and feeding it into the upper cavity of the transducer mounting post 22. The transducer mounting post 22 is then inserted into the hole of the transducer post mounting base 33, with its lower end extending into the lower positioning groove 113 for directional positioning. Notably, unlike the previous method, the flow guide shroud here has no external threads, and the through hole has no internal threads; therefore, the flow guide shroud 23 is simply squeezed into the blind hole of the transducer mounting post 22 for a tight fit. Finally, using a flat-headed fine needle, inject two-component A and B high-strength adhesive into the flow guide through the wire-passing oblique hole 223. The sealing ring 231 on the flow guide serves to prevent leakage during adhesive injection, while the grooved barb structure 232 at the lower end of the flow guide, after combining with the A and B adhesives, serves to tighten and fix the flow guide 23.

[0084] Experiments show that for plane waves, the installation of a pair of through-beam transducers requires that the emitting surfaces of the two transducers be strictly parallel; even a small angular deviation will cause a significant attenuation of the received signal amplitude. Conversely, a small displacement (e.g., 1mm misalignment) of the centerlines of the two parallel transducers has almost no attenuation of the received signal amplitude. Therefore, maintaining the parallelism of the emitting (receiving) surfaces of the two transducers is crucial. The transducer fixing post 22 described in this application is positioned and installed at its lower end within the transducer post positioning groove 113 for directional and angular positioning. The transducer post positioning groove 113 is a rectangular blind hole. Its upper end is installed in the through hole of the transducer post mounting base 33, and its height is positioned by the positioning platform 331. The upper outer ring of the transducer fixing post has a side seal 224 and a top seal 225, forming a two-stage, two-type sealing system to ensure reliable sealing. The elastic gasket 25 is located above the top seal 225 of the transducer fixing post. The outer thread cap 26 is located above the elastic washer 25. By tightening the central hexagonal screw hole of the outer thread cap 26, its outer thread is connected to the internal thread of the transducer column mounting base 33, pressing the transducer fixing column 22 tightly onto the positioning table 331 to position its height.

[0085] Since the base metal outer tube 11 is forged / cast, the local diameter of the transducer fixing column inner cavity 114 between the transducer fixing column 22 and the inner cavity of the metal outer tube can be enlarged as needed. Therefore, the gap between the transducer fixing column 22 and the inner cavity of the metal outer tube 11 can easily meet the requirement of ≥3mm. In terms of processing, the outer diameter and inner diameter of the metal tube in the transducer placement area are relatively large, and the inner cavity is machined using an internal groove turning tool, which is a conventional and extremely convenient process.

[0086] For this embodiment, which is an application of a hot water meter, high requirements are placed on the range ratio and accuracy. Since it is processed by injection molding of PPS / PT engineering plastics using the same mold, the transducer fixing column 22 and the inner lining rectifier tube 66 have a high degree of consistency, ensuring the consistency of the flow channel and performance of batch products, which plays an important role in simplifying the subsequent testing and calibration of the flow meter.

[0087] The lower casing 77A of the instrument circuit box is conveniently and easily fixed to the lower casing fixing screw hole 34 on the transducer column mounting base 33 by fixing screws 27. If IP68 waterproofing is required, the inside of the instrument box 77 can be filled with transparent waterproof glue.

[0088] In this embodiment, in addition to measuring the hot water flow rate, it is also necessary to collect the heat energy carried by the fluid. Therefore, a temperature sensor 441 must be installed. Since the integral metal outer tube 11 is forged / cast, this type of through-beam ultrasonic hot water meter, which is adapted to a DN15 diameter transducer column, not only facilitates the installation of the temperature sensor base 44, but also makes it very convenient to install the temperature sensor 441 because no internal sealing is required. Because the temperature sensor base is placed at the outer end of the metal outer tube near the outlet, the temperature sensor 441 can be easily installed in the temperature sensor base 44. At the outlet position, the temperature sensor's measuring rod is obliquely inserted outside the transducer flow guide shroud 23, without affecting the measurement of the fluid.

[0089] The above examples illustrate the implementation and application of the present invention, which is a column-fixed through-beam ultrasonic water meter adapted to a DN15 diameter transducer. 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 are within the scope of protection claimed by the present invention.

Claims

1. A fixed-beam ultrasonic water meter adapted to DN15 orifice transducer stand, characterized in that The device includes a metal outer tube (11), a transducer (24), a transducer column mounting base (33), a flow guide (23), a transducer fixing column (22), a positioning platform (331), a transducer column lower positioning groove (113), a wire guide oblique hole (223), an external thread cap (26), an instrument circuit box lower shell (77A), and a temperature sensor base (44); wherein, the two ends of the metal outer tube (11) are respectively connected to the external pipe of the flow to be measured through pipe thread one (111) and pipe thread two (112); and the two ends of the metal outer tube (11) are provided with A transducer column mounting base (33) is provided for mounting transducer fixing columns (22). A transducer (24) and a flow guide (23) assembled and connected with the transducer fixing columns (22) are mounted on the transducer fixing columns (22). Thus, a double-beam transducer (24) is formed inside the metal outer tube (11). An inner lining rectifier tube (66) is embedded in the inner wall of the central area of ​​the metal outer tube (11). The metal outer tube (11) is formed by forging / casting, and the minimum water passage gap inside the tube is greater than 3mm. The internal positioning of the metal outer tube (11) is as follows: The platform (331) and the positioning groove (113) are machined by a special machine in one multi-hole positioning process; the metal outer tube (11) has a transducer column mounting seat (33) and a transducer column lower positioning groove (113); the lower end of the transducer fixing column (22) is positioned and installed in the transducer column lower positioning groove (113) for direction and angle positioning; the transducer column lower positioning groove (113) is a rectangular blind hole; and the upper end of the transducer fixing column (22) is installed in the hole of the transducer column mounting seat (33), and the height is positioned by the positioning platform (331); The upper outer ring of the transducer fixing column (22) has a side seal (224) and a top seal (225) forming two levels and two sealing forms; the elastic washer (25) is located above the top seal (225); the outer thread cap (26) is located above the elastic washer (25), and by tightening the center hexagonal screw hole of the outer thread cap (26), its external thread is connected to the internal thread of the transducer column mounting base (33), pressing the transducer fixing column (22) tightly on the positioning table (331) to position the height; the transducer signal line (28) is led out through the wire through oblique hole (223).

2. The fixed-beam ultrasonic water meter according to claim 1, characterized in that: The metal outer tube (11) is formed by integrated forging / casting of brass / stainless steel. The transducer column mounting seat (33) on the metal outer tube (11) and the diameter change of the tube are formed by stamping / casting in one go using the same mold, and the outer tubes are consistent.

3. The column-fixed through-beam ultrasonic water meter adapted to a DN15 diameter transducer as described in claim 1, characterized in that: The transducer fixing column (22) and the inner lining rectifier tube (66) are manufactured by PPS / PPT through precision injection mold; the inner lining rectifier tube (66) is located in the middle of the metal outer tube body (11) and is fixed by the rectifier tube fixing bolt (55).

4. The fixed-beam ultrasonic water meter according to claim 1, wherein the stand is adapted for a DN15 transducer. The first method of transducer installation and fixing is as follows: a complete transducer (24) is installed in the through hole (222). The transducer is sealed by the sealing ring two (241) and positioned by the transducer positioning platform (221). The transducer signal line (28) is led out from the rear end of the transducer. The rear end of the transducer is screwed into the internal thread hole of the transducer fixing post (22) by a tool with an external threaded guide cover (23) to press the transducer (24). The specific operation process of this method is as follows: the transducer and the transducer signal line are assembled by installing the transducer (24) in the through hole (222), passing the transducer signal line (28) through the wire guide oblique hole (223) and sending it to the upper cavity of the transducer fixing post (22); next, the transducer fixing post (22) is inserted into the hole of the transducer post mounting base (33) and lowered. The end is inserted into the positioning groove (113) under the transducer column for directional positioning. Then, using a tool, the external thread of the flow guide (23) is screwed into the through hole (222) of the internal thread of the transducer fixing column to press the transducer (24). In order to better guide the fluid, the flow guide (23) has a certain length, so it must be installed from the end of the metal outer tube after the transducer fixing column (22) is installed. For this transducer installation method, the through hole (222) of the transducer fixing column is located at the end where the flow guide is installed, and has several turns of internal thread. Finally, using a flat-headed fine needle, inject two-component A and B high-strength glue into the flow guide (23) through the wire oblique hole (223) to fix the flow guide (23) to the transducer fixing column (22). The sealing ring (231) on the flow guide plays a role in preventing leakage when injecting glue.

5. The fixed-beam ultrasonic water meter according to claim 1, wherein the stand is adapted for a DN15 transducer. 5 The second method of transducer installation and fixing is as follows: the transducer and the transducer fixing post (22) are integrated into one structure. The transducer assembly (242) is directly encapsulated in the blind hole (2222) in the middle of the transducer fixing post (22). Then, the transducer fixing post (22) is inserted into the hole of the transducer post mounting base (33), and its lower end is inserted into the positioning groove (113) under the transducer post for directional positioning. Unlike the first method of transducer installation and fixing described in claim 4, the guide shroud (23) here does not have external threads, and the blind hole (242) is not threaded. Since there is no internal thread inside 222), the flow guide (23) is squeezed into the blind hole (2222) of the transducer fixing post (22) and tightly fitted. The transducer signal line (28) is led out through the wire guide oblique hole (223). Finally, a flat-headed fine needle is used to inject two-component A and B epoxy glue into the flow guide through the wire guide oblique hole (223). The sealing ring 1 (231) on the flow guide plays a role in preventing leakage during glue injection. The barb structure (232) at the lower end of the flow guide, after being combined with A and B glue, plays a role in tightening and fixing the flow guide (23).

6. The fixed-beam ultrasonic water meter according to claim 1, wherein the stand is adapted for a DN15 transducer. The lower shell (77A) of the instrument circuit box is fixedly connected to the lower shell fixing screw hole (34) on the transducer column mounting base (33) by fixing screws (27).

7. The fixed-beam ultrasonic water meter according to claim 1, wherein the stand is adapted for a DN15 transducer. The metal outer tube (11) is provided with a temperature sensor seat (44) at the water outlet position, and the temperature sensor (441) is installed in the temperature sensor seat (44).

Images