Ultrasonic transducer assembly and ultrasonic flow meter
By combining the clamping flange and clamping bolts with an elastic ring, the signal distortion and error offset problems caused by transducer installation in ultrasonic flow meters are solved, thereby improving metering accuracy and reliability and adapting to pressure changes within the flow channel.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU QINCHUAN IOT TECH CO LTD
- Filing Date
- 2023-08-07
- Publication Date
- 2026-06-26
Smart Images
Figure CN117029941B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of metering device technology, and in particular to an ultrasonic transducer assembly structure and an ultrasonic flow meter. Background Technology
[0002] Flow meters are essential metering devices in natural gas pipeline systems. For a long time, the most common types of flow meters used in natural gas pipeline systems have been turbine flow meters and orifice plate flow meters. Mechanical metering devices have complex structures and are prone to blockage and corrosion of components due to water vapor, particulate matter, and other impurities carried in natural gas. This not only reduces the lifespan of the flow meter but also severely hinders accurate metering. Ultrasonic gas flow meters, on the other hand, utilize the relationship between the propagation speed of ultrasonic pulses in the airflow and the airflow velocity to determine the gas flow rate. Specifically, the ultrasonic pulse propagates faster with the flow direction than against the flow direction, and the greater the time difference between these two propagation speeds, the greater the flow rate. In recent years, with the development of ultrasonic metering technology, ultrasonic flow meters have not only significantly reduced costs but also, because their core structure consists of a circuit module and a transducer, ensure that their performance and lifespan are not excessively affected by the fluid medium. This results in ideal metering accuracy under various operating conditions, and they have now become internationally recognized natural gas metering devices.
[0003] The ultrasonic transducer is a core component of the ultrasonic flow meter. Application number CN 202021914402.X, entitled "A Sealing Device for an IoT Ultrasonic Flow Meter Transducer," is a prior technical solution proposed by the applicant regarding the installation method of ultrasonic transducers. In this solution, by setting relevant ultrasonic transducer clamping methods (with built-in threads for locking) and sealing forms, vibration buffering, ensuring the sealing reliability of corresponding connection positions, and centering stability can be effectively achieved. Other solutions include those provided in patent application CN201920660830.5, entitled "A Gas Ultrasonic Flow Meter Transducer," which is essentially a snap-fit ultrasonic transducer connection solution. Other existing technologies include ultrasonic transducer installation solutions such as welding connections.
[0004] The mounting method of the ultrasonic transducer has a direct impact on the performance of the ultrasonic flow meter, and it is necessary to further optimize the mounting method. Summary of the Invention
[0005] To address the aforementioned optimization of ultrasonic transducer mounting methods, this invention provides an ultrasonic transducer assembly structure and an ultrasonic flow meter. The structural design provided by this solution effectively solves the problems of measurement signal distortion caused by ultrasonic transducer installation and error offset caused by multiple assembly steps.
[0006] To address the above problems, the ultrasonic transducer assembly structure and ultrasonic flow meter provided by the present invention solve the problems through the following technical points: the ultrasonic transducer assembly structure includes a flow channel, a connecting seat disposed on the flow channel, and an ultrasonic transducer mounted on the connecting seat.
[0007] The central hole of the connector is a stepped hole, and the stepped hole has a stepped surface facing outward from the central hole;
[0008] The ultrasonic transducer includes a transducer housing, which is supported on the stepped surface by a first elastic ring.
[0009] The outer end face of the connecting seat is a first plane perpendicular to the central hole, and it also includes a clamping flange. The clamping flange is provided with a second plane. The clamping flange is fixed to the connecting seat by multiple clamping bolts. After the clamping bolts are tightened, the first plane and the second plane are in contact, and the first elastic ring undergoes compressive elastic deformation in the axial direction of the central hole.
[0010] The outer end face of the transducer housing acts directly or indirectly on the inner end face of the clamping flange, and the inner end face of the clamping flange defines the position of the transducer housing on the axis of the central hole and defines the axial direction of the transducer housing.
[0011] In existing technologies, factors affecting the performance of ultrasonic flow meters include: the geometry of the flow meter body, the position of the ultrasonic transducer, and the uncertainty of known parameters (including temperature and pressure coefficients). These factors are generally considered intrinsic. Intrinsic factors also include the accuracy or reliability of the electronic components used, the transit time calculation method, and the accuracy of calibration compensation. Other extrinsic factors affecting the performance of ultrasonic flow meters include: flow velocity profile, temperature distribution, fluid pulsation, acoustic and electromagnetic noise, contaminants, and the dimensional stability of the flow meter body parts. Therefore, to ensure the metering performance of ultrasonic flow meters, the hardware design needs to consider the uniformity of flow velocity distribution across the fluid profile, fluid pulsation, the accuracy of the ultrasonic transducer installation position, and the repeatability of the installation position.
[0012] Regarding the installation of ultrasonic transducers in flow channels, the snap-fit installation method is characterized by its simple structure and convenient assembly and disassembly. When the structural design incorporates snap-fit and guide components, it offers relatively high installation accuracy, but also suffers from a larger structural volume. The method of directly threading the ultrasonic transducer housing onto its outer side for locking is convenient for installation and removal, and suitable for applications with high fluid pressure. However, due to the inherent clearance in the threaded fit, the thread machining accuracy, and deformation during use, the ultrasonic transducer can easily become non-coaxially mounted, causing signal distortion. Furthermore, differences in the locking force between two mating operations can also lead to measurement error deviations. Besides these two installation methods, welding is also an option. The current connection method is a non-detachable connection, which is detrimental to the maintenance of the ultrasonic transducer and flow channel. Furthermore, the heat introduced by welding is unfavorable to the temperature stability of the meter body parts. Therefore, this solution provides an ultrasonic transducer assembly structure that differs from existing technologies. In practical applications, the ultrasonic transducer proposed in this solution includes a transducer housing and a sensor assembly installed inside the housing. The ultrasonic transducers are used in pairs, each including ultrasonic signal transmission and acquisition functions. The accuracy of the ultrasonic transducer installation position determines the measurement time of the ultrasonic flow meter (depending on the installation position, it may affect the transmission time t of the ultrasonic wave in the fluid portion outside the sound channel (where the fluid velocity is 0)). c The influence of ultrasonic wave propagation time t in the fluid flowing within the flow channel AB By adopting the ultrasonic transducer installation method proposed in this solution, the problem of measurement signal distortion caused by ultrasonic transducer installation position error and the error offset problem after multiple assembly can be effectively improved.
[0013] More specifically, ultrasonic transducers are generally coaxially mounted on a connector. The coaxial mounting includes the following prior art: the inner side of the connector is connected to the flow channel, the connector has a central hole, which is circular, and the coaxial mounting is generally constrained by a sealing ring (the second elastic ring provided in the following scheme) set between the outer wall of the transducer housing and the wall of the central hole. Unlike existing technologies, this solution uses clamping bolts and clamping flanges to define the position of the transducer housing on the axis of the central hole and to define the axial direction of the transducer housing. It has the following characteristics: By including a first plane and a second plane, when the clamping bolts are tightened so that the first plane and the second plane are in contact, the inner end face of the clamping flange can be constrained to have a specific inner end face position and inner end face plane direction relative to the flow channel through direct or indirect action. When the inner end face of the clamping flange is used to constrain the outer end face of the transducer housing, the specific inner end face position and inner end face plane direction can effectively ensure the axial direction of the transducer housing and the connecting seat, and ensure that the transducer housing is located in a specific position on the axis of the connecting seat. Compared to threaded connection schemes that directly set external threads on the transducer housing and internal threads on the central hole, this solution maintains the planar position and planar direction of the inner end face of the clamping flange through planar contact, effectively avoiding... The threadless connection pair addresses the issue of ensuring the coaxiality of the transducer housing on the connector due to machining precision, deformation, and clearance (in existing technologies, the force exerted by the corresponding thread on the transducer housing is much greater than the supporting force provided by the second elastic ring, so the second elastic ring does not necessarily undergo ideal uniform deformation at various positions in the circumferential direction). This effectively avoids the problem of inaccurate control over the screw-in depth caused by the machining precision and deformation of the corresponding thread, even when torque is used to screw the transducer housing in. By configuring it to include a first elastic ring and a stepped surface, with the stepped surface facing outwards from the central hole, the transducer housing supported on the stepped surface by the first elastic ring, and the first elastic ring undergoing compressive elastic deformation after the clamping bolts are tightened, firstly, the elastic restoring force of the first elastic ring can be used to prevent the clamping bolts from loosening, maintaining the fit between the first and second planes. Secondly, the first elastic ring can also serve as an axial seal for the gap between the ultrasonic transducer and the connector, ensuring the reliability of the ultrasonic flowmeter's seal.
[0014] In summary, this solution, given a fixed size for components such as the flow channel and connecting seat, utilizes flange connections. By clamping the inner end face of the flange against the outer end face of the connecting seat to constrain the outer side of the transducer housing, and using a first elastic ring to ensure the reliability of these constraints, it effectively solves the problems of measurement signal distortion caused by ultrasonic transducer assembly errors (determined by the specific position of the sensor assembly in the flow channel) and error offset caused by multiple assemblies (determined by the repeatability of the specific position of the sensor assembly in the flow channel). Furthermore, this solution has a simple structure, is smaller in size compared to snap-fit connections, and facilitates the assembly and disassembly of the ultrasonic transducer.
[0015] In addition, this solution uses a compression method to fix the ultrasonic transducer, and the position of the compression flange is ensured by corresponding surface mating. The flow channel can be considered an internal pressure vessel relative to the outside. When the pressure fluctuates in the flow channel, compared with the solution where the ultrasonic transducer is directly screwed into the connecting seat by threads, the threads on the compression bolts in this solution can undergo greater elastic deformation. Therefore, under a certain range of internal pressure changes, the pressure change in the flow channel will not cause the position of the compression flange to change. Thus, the assembly structure adopted in this solution can prevent the ultrasonic transducer from retracting under different working pressures.
[0016] As those skilled in the art, the above-mentioned method of using a second elastic ring to constrain the position of the ultrasonic transducer axis in the radial direction of the connecting seat is existing technology. The above solution actually only requires the protection of the ultrasonic transducer end constraint, solving the coaxiality problem and the specific position problem of the sensor assembly from the aspects of the ultrasonic transducer axis direction and end position. In specific applications, depending on the designed mating dimensions, if necessary, the machining accuracy of the parts and the second elastic ring can be selected to achieve the positioning of the ultrasonic transducer axis in the radial direction of the central hole.
[0017] As a further technical solution to the ultrasonic transducer assembly structure:
[0018] The transducer housing has an annular flange at its outer end, and the first elastic ring is clamped between the stepped surface and the inner end face of the annular flange. In this design, the first elastic ring is a crucial component for reliably fixing the transducer housing. This design provides a specific way to set the first elastic ring: the structure of clamping the first elastic ring between the stepped surface and the annular flange ensures the fixed position and functional reliability of the first elastic ring. The structure is simple. In practical implementation, based on the specific structural design of the ultrasonic transducer, a flange protruding outward from the side of the ultrasonic transducer body is provided at the outer end of the ultrasonic transducer to form the annular flange. In practical applications, the transducer housing is generally a metal housing, and the structure formed by the annular flange and the transducer housing is preferably an integral structure: the annular flange and the transducer housing are designed as a single unit.
[0019] The transducer housing has a cylindrical structure, and the central hole is circular. It also includes a second elastic ring disposed between the wall of the central hole and the outer wall of the transducer housing. This second elastic ring serves as an axial seal in the gap between the central hole wall and the outer wall of the transducer housing. In this design, the second elastic ring not only serves as an axial seal in the corresponding gap but also as an angular constraint component providing radial constraint along the central hole to the side of the transducer housing, thus maintaining coaxiality relative to the connecting seat. It is important to note that in this design, the fit between the first and second planes maintains a specific planar position and orientation of the inner end face of the clamping flange. Regarding the coaxiality of the transducer housing relative to the connecting seat, the outer end face of the transducer housing, directly or indirectly constrained by the inner side of the clamping flange, controls the axial direction and end position of the ultrasonic transducer. Since the constraint of the axial direction and end position is ultimately achieved through the fit between the first and second planes, the thread fit accuracy between the clamping bolt and the connecting seat will not cause uneven deformation of the second elastic ring in the circumferential direction. Therefore, when designing and selecting the second elastic ring, its deformation resistance does not need to be considered. Under these structural characteristics, compared to existing ultrasonic transducer fixing methods, a second elastic ring with a smaller outer diameter and smaller compression can be used. This is beneficial for controlling noise interference from the sensor assembly (such as noise within the ultrasonic range emitted by control valves on the pipeline). The smaller compression of the second elastic ring reduces the contact area between the second elastic ring and the connecting seat and transducer housing, which is beneficial for controlling the propagation of surface sound from the flow channel.
[0020] The second elastic ring is installed on the transducer housing through an annular groove on the outer wall of the transducer housing. The number of second elastic rings is greater than 1, and they are arranged at intervals on the axis of the transducer housing.
[0021] Both the first and second elastic rings are rubber O-rings. This solution provides a technical approach that facilitates the installation of the second elastic ring, ensuring axial sealing reliability and maintaining coaxiality accuracy: the second elastic ring is pre-installed on the transducer housing and then embedded in the central hole along with the transducer housing; by setting the number of second elastic rings to be greater than one, multiple seals can be formed in the gas leakage direction, reducing the contact area between the second elastic ring and the transducer housing and connecting seat when the sealing purpose is achieved, thus facilitating noise control. The use of rubber O-rings for both the first and second elastic rings also benefits the noise blocking control from the perspective of the acoustic path cross-sectional area.
[0022] Regarding the aforementioned noise control, a further application is as follows: both the first and second elastic rings are coated with a Teflon surface layer. The Teflon surface layer serves as the contact layer between the first elastic ring and the connecting seat and / or the transducer housing, and the Teflon surface layer serves as the contact layer between the second elastic ring and the connecting seat and / or the transducer housing. The material properties of Teflon itself are used to block the propagation of sound through the surface, thereby improving the signal acquisition quality of the sensor assembly.
[0023] The outer end face of the transducer housing indirectly acts on the inner end face of the clamping flange; it also includes a pad sandwiched between the outer end face of the transducer housing and the inner end face of the clamping flange, the pad being a flat pad made of plastic.
[0024] After the clamping bolts are tightened, the outer end face of the transducer housing and the inner end face of the clamping flange are parallel planes to each other, the inner end face of the gasket is in contact with the outer end face of the transducer housing, and the outer end face of the gasket is in contact with the inner end face of the clamping flange.
[0025] The transducer housing is spaced apart from the connecting seat. In the structure of the ultrasonic flow meter, this solution uses bolted connections to fix the ultrasonic transducer to the connecting seat. The flow channel, connecting seat, clamping flange, and clamping bolts should preferably be made of metal. This not only solves the problem of excessive measurement error caused by mechanical dimensional changes due to linear expansion, but also solves the problem of connection reliability. In this context, from the perspective of noise reduction of the sensor assembly, the first elastic ring, or the first elastic ring and the second elastic ring working together, can achieve the separation (non-direct contact) between the ultrasonic transducer and the connecting seat. The indirect effect is achieved through the pad, which can further utilize the blocking effect of the pad on the sound propagation of the meter body to further improve the signal acquisition quality of the sensor assembly. In specific applications, the end faces of both ends of the pad are set to be planes perpendicular to the axis of the end plate, and the second plane is a plane perpendicular to the axis of the clamping flange.
[0026] The inner end face of the clamping flange has a boss, which is embedded in the central hole and acts on the outer end face of the pad. This solution aims to provide a watch body structure that is easy to assemble and whose assembly accuracy can be controlled: the boss being embedded in the central hole is a kind of embedded installation of the inner end face of the clamping flange in the central hole. Through the cooperation of this end face with the outer end face of the pad, the first elastic ring, the ultrasonic transducer, and the pad are all recessed and installed in the central hole. In the above process, the hole wall of the central hole can provide lateral support for the corresponding parts to position them. After the above components are assembled, the clamping flange is then installed on the outer side of the pad to realize the assembly of the relevant watch body structure.
[0027] The gasket is made of Teflon. This solution provides a specific gasket selection method. First, the non-stick properties, thermal stability, wear resistance, corrosion resistance, and sliding properties of Teflon itself can be utilized to ensure the smoothness of the corresponding mating surfaces, the dimensional accuracy and positional accuracy of the surface structure, and reduce the possibility of the ultrasonic transducer axis deviating from the connecting seat axis due to friction during the assembly of the clamping flange. In addition, Teflon is a high-performance sound-blocking material, and this material selection is very beneficial for the gasket to block the sound propagation of the surface.
[0028] Both the gasket and the clamping flange are ring-shaped structures with a central hole, and the holes on the gasket and the clamping flange are interconnected. This solution provides a technical solution that utilizes the hole as a wire-passing hole on the structure of this device: the cable led out from the rear end (outer end) of the sensor assembly can be led out through the hole.
[0029] This solution provides an ultrasonic flow meter, including the ultrasonic transducer assembly structure described in any of the above embodiments. The ultrasonic flow meter includes the ultrasonic transducer assembly structure, which represents a specific application of the ultrasonic transducer assembly structure.
[0030] A further improvement to the ultrasonic flow meter is as follows:
[0031] The flow channel is provided with multiple connecting seats, and each connecting seat is equipped with an ultrasonic transducer. The ultrasonic transducers form a dual-channel or multi-channel through-beam arrangement. As those skilled in the art know, in the prior art, according to the channel arrangement method, there are single-channel through-beam arrangements, V-shaped reflection arrangements, U-shaped reflection arrangements, and dual (multi)-channel through-beam arrangements. This solution aims to provide a flow meter that utilizes relevant channel design to achieve short channel length, suitability for large-diameter flow meters, good repeatability, and high accuracy in the form of a flow meter.
[0032] The present invention has the following beneficial effects:
[0033] This solution, with fixed dimensions for components such as the flow channel and connecting seat, employs flange connections. By clamping the inner end face of the flange against the outer end face of the connecting seat to constrain the outer side of the transducer housing, and using a first elastic ring to ensure the reliability of these constraints, it effectively solves the problem of measurement signal distortion caused by ultrasonic transducer assembly errors (determined by the specific position of the sensor assembly in the flow channel) and error offset problems caused by multiple assembly steps (determined by the repeatability of the specific position of the sensor assembly in the flow channel). Furthermore, this solution has a simple structure, is smaller in size compared to snap-fit connections, and facilitates the assembly and disassembly of the ultrasonic transducer.
[0034] In this solution, the ultrasonic transducer is fixed using a compression method, and the position of the compression flange is ensured by corresponding surface mating. The flow channel can be considered an internal pressure vessel relative to the outside world. When the pressure fluctuates within the flow channel, compared to the solution where the ultrasonic transducer is directly screwed into the connecting seat by threads, the threads on the compression bolts in this solution can undergo greater elastic deformation. Therefore, under a certain range of internal pressure changes, the pressure changes within the flow channel will not cause the position of the compression flange to change. Thus, the assembly structure adopted in this solution can prevent the ultrasonic transducer from retracting under different working pressures. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of a specific embodiment of the ultrasonic flow meter described in this solution;
[0036] Figure 2 For along Figure 1 The cross-sectional view obtained by cutting through AA as shown;
[0037] Figure 3 for Figure 2 A magnified view of part A shown.
[0038] The reference numerals in the attached figures are as follows: 1, flow channel; 2, ultrasonic transducer; 21, connecting seat; 22, clamping flange; 23, gasket; 24, first elastic ring; 25, second elastic ring; 26, transducer housing; 27, sensor assembly; 28, clamping bolt; 29, annular flange. Detailed Implementation
[0039] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments:
[0040] Example 1:
[0041] like Figures 1 to 3 As shown, the ultrasonic transducer assembly structure includes a flow channel 1, a connecting seat 21 disposed on the flow channel 1, and an ultrasonic transducer 2 mounted on the connecting seat 21.
[0042] The central hole of the connecting seat 21 is a stepped hole, and the stepped hole has a stepped surface facing outward from the central hole;
[0043] The ultrasonic transducer 2 includes a transducer housing 26, which is supported on the stepped surface by a first elastic ring 24.
[0044] The outer end face of the connecting seat 21 is a first plane perpendicular to the central hole. It also includes a clamping flange 22. The clamping flange 22 is provided with a second plane. The clamping flange 22 is fixed to the connecting seat 21 by multiple clamping bolts 28. After the clamping bolts 28 are tightened, the first plane and the second plane are in contact, and the first elastic ring 24 undergoes compressive elastic deformation in the axial direction of the central hole.
[0045] The outer end face of the transducer housing 26 acts directly or indirectly on the inner end face of the clamping flange 22, and the inner end face of the clamping flange 22 defines the position of the transducer housing 26 on the axis of the central hole and defines the axial direction of the transducer housing 26.
[0046] In existing technologies, factors affecting the performance of ultrasonic flow meters include: the geometry of the flow meter body, the position of the ultrasonic transducer 2, and the uncertainty of known parameters (including temperature and pressure coefficients). These factors are generally considered intrinsic, and also include the accuracy or reliability of the electronic components used, the transit time calculation method, and the accuracy of calibration compensation. Other extrinsic factors affecting the performance of ultrasonic flow meters include: flow velocity profile, temperature distribution, fluid pulsation, acoustic and electromagnetic noise, contaminants, and the dimensional stability of the flow meter body parts. Therefore, to ensure the metering performance of ultrasonic flow meters, the hardware design needs to consider the uniformity of flow velocity distribution across the fluid profile, fluid pulsation, the accuracy of the ultrasonic transducer 2 installation position, and the repeatability of the installation position.
[0047] During the research on ultrasonic transducer assembly, the applicant discovered that, regarding the installation of ultrasonic transducer 2 on flow channel 1, the snap-fit installation method has the advantages of simple structure and convenient assembly and disassembly. When the structural design uses snap-fit and guide components, it has the advantage of relatively high installation accuracy, but it also has the problem of large structural volume. The method of directly setting threads on the outer side of the ultrasonic transducer 2 housing for locking is convenient for installation and disassembly and suitable for high fluid pressure applications. However, due to the gap in the thread fit, the machining accuracy of the threads, and deformation during use, the ultrasonic transducer 2 is prone to non-coaxial installation, causing signal distortion. Furthermore, the difference in locking force between two mating operations can also cause measurement error deviations. Besides the above two installation methods... In addition, there is the welding connection method, which is a non-detachable connection method, which is detrimental to the maintenance of ultrasonic transducer 2 and flow channel 1. At the same time, the heat introduced by welding is detrimental to the temperature and geometry of the body parts. Based on this, this solution provides an ultrasonic transducer 2 assembly structure that is different from the prior art: In specific applications, the ultrasonic transducer 2 proposed in this solution includes a transducer housing 26 and a sensor assembly 27 installed inside the transducer housing 26. The ultrasonic transducers 2 are used in pairs and each includes ultrasonic signal transmission and ultrasonic signal acquisition functions. The installation position accuracy of the ultrasonic transducer 2 determines the measurement time of the ultrasonic flow meter (depending on the installation position, it may affect the transmission time t of the ultrasonic wave in the fluid part outside the sound channel (where the fluid velocity is 0)). c The influence of ultrasonic wave propagation time t in the fluid flowing in channel 1 AB By adopting the installation method of the ultrasonic transducer 2 proposed in this solution, the problem of measurement signal distortion caused by the installation position error of the ultrasonic transducer 2 and the error offset problem after multiple assembly can be effectively improved.
[0048] More specifically, the ultrasonic transducer 2 is generally coaxially mounted on the connecting seat 21. This coaxial mounting includes the following prior art: the inner side of the connecting seat 21 is connected to the flow channel 1, and the connecting seat 21 has a central hole, which is circular. The coaxial mounting is generally constrained by a sealing ring (the second elastic ring 25 provided in the following scheme) placed between the outer wall of the transducer housing 26 and the wall of the central hole. Unlike prior art, this scheme uses clamping bolts 28 and clamping flanges 22, etc., to define the position of the transducer housing 26 on the axis of the central hole and to define the axial direction of the transducer housing 26. It has the following characteristics: by including the first plane and the second plane, when the clamping bolts 28 are tightened so that the first plane and the second plane are in contact, through the direct or indirect action, the inner end face of the clamping flange 22 can be constrained to have a specific inner end face position and inner end face plane direction relative to the flow channel 1. When the inner end face of the clamping flange 22 is used to constrain the outer end face of the transducer housing 26, the specific position and plane orientation of the inner end face can effectively ensure the axial direction of the transducer housing 26 and the connecting seat 21, and ensure that the transducer housing 26 is located in a specific position on the axis of the connecting seat 21. Compared with the threaded connection scheme of directly setting external threads on the transducer housing 26 and internal threads on the center hole, this scheme maintains the plane position and plane orientation of the inner end face of the clamping flange 22 through plane contact, which can effectively avoid thread... The threaded connection pair has the problem of difficulty in ensuring the coaxiality of the transducer housing 26 on the connecting seat 21 due to machining accuracy, deformation, and gaps (in the prior art, the force of the corresponding thread on the transducer housing 26 is much greater than the support force provided by the second elastic ring 25 to the transducer housing 26, so the second elastic ring 25 may not undergo ideal uniform deformation at various positions in the circumferential direction). This can effectively avoid the problem of inaccurate control of the screwing depth due to the machining accuracy and deformation of the corresponding thread, even if torque is used to screw in the transducer housing 26. By setting it to include the first elastic ring 24 and the stepped surface, with the stepped surface facing the outside of the central hole, the transducer housing 26 is supported on the stepped surface by the first elastic ring 24, and the first elastic ring 24 undergoes compressive elastic deformation after the clamping bolt 28 is tightened. First, the elastic restoring force of the first elastic ring 24 can be used to prevent the clamping bolt 28 from loosening and maintain the fit between the first plane and the second plane. Second, the first elastic ring 24 can also serve as an axial seal for the gap between the ultrasonic transducer 2 and the connecting seat 21 to ensure the reliability of the ultrasonic flow meter seal.
[0049] In summary, given a fixed size for components such as the flow channel 1 and the connecting seat 21, this solution utilizes flange connections and applies constraints to the outer side of the transducer housing 26 by tightening the inner end face of the flange 22 and the outer end face of the connecting seat 21. The reliability of these constraints is ensured by the first elastic ring 24. This effectively solves the problem of measurement signal distortion caused by assembly errors of the ultrasonic transducer 2 (determined by the specific position of the sensor assembly 27 on the flow channel 1) and the error offset problem caused by multiple assembly steps (determined by the repeatability of the specific position of the sensor assembly 27 on the flow channel 1). Furthermore, this solution has a simple structure, is smaller in size compared to snap-fit connections, and facilitates the assembly and disassembly of the ultrasonic transducer 2.
[0050] In addition, the ultrasonic transducer 2 is fixed in a compression manner in this solution, and the position of the compression flange 22 is ensured by the corresponding surface mating. The flow channel 1 can be regarded as an internal pressure vessel relative to the outside. When the pressure in the flow channel 1 fluctuates, compared with the solution where the ultrasonic transducer 2 is directly screwed into the connecting seat 21 by threads, the threads on the compression bolt 28 in this solution can undergo greater elastic deformation. Therefore, under a certain range of internal pressure changes, the pressure change in the flow channel 1 will not cause the position of the compression flange 22 to change. Thus, the assembly structure adopted in this solution can prevent the position of the ultrasonic transducer 2 from retracting under different working pressures.
[0051] As those skilled in the art, the above-mentioned method of using the second elastic ring 25 to constrain the position of the ultrasonic transducer 2 axis in the radial direction of the connecting seat 21 is itself prior art. The above solution actually only requires the protection of the end constraint of the ultrasonic transducer 2, solving the coaxiality problem and the specific position problem of the sensor assembly 27 from the aspects of the axial direction of the ultrasonic transducer 2 and the end position. In specific applications, according to the designed mating dimensions, if necessary, the machining accuracy of the parts and the second elastic ring 25 can be selected to achieve the positioning of the ultrasonic transducer 2 axis in the radial direction of the central hole.
[0052] Example 2:
[0053] This embodiment is a further refinement of embodiment 1:
[0054] The transducer housing 26 has an annular flange 29 at its outer end, and the first elastic ring 24 is clamped between the stepped surface and the inner end face of the annular flange 29. In this design, the first elastic ring 24 is a crucial component for reliably fixing the transducer housing 26. This design provides a specific way to set the first elastic ring 24: the structure of clamping the first elastic ring 24 between the stepped surface and the annular flange 29 ensures the fixed position and functional reliability of the first elastic ring 24. Simultaneously, the structure is simple. In specific implementation, based on the specific structural design of the ultrasonic transducer 2, the annular flange 29 is formed by a flange protruding outward from the side of the main body of the ultrasonic transducer 2 at its outer end. In practical applications, the transducer housing 26 is generally a metal housing, and the structure formed by the annular flange 29 and the transducer housing 26 is preferably an integral structure: the annular flange 29 and the transducer housing 26 are designed as a single unit.
[0055] Example 3:
[0056] This embodiment is a further refinement of embodiment 1:
[0057] The transducer housing 26 has a cylindrical structure, and the central hole is circular. It also includes a second elastic ring 25 disposed between the wall of the central hole and the outer wall of the transducer housing 26. The second elastic ring 25 serves as an axial seal in the gap between the wall of the central hole and the outer wall of the transducer housing 26. In this design, the second elastic ring 25 not only serves as an axial seal in the corresponding gap but also as an angular constraint component providing radial constraint along the central hole to the side of the transducer housing 26, thus maintaining coaxiality relative to the connecting seat 21. It should be noted that in this solution, the contact between the first and second planes maintains a specific planar position and orientation of the inner end face of the clamping flange 22. While maintaining the coaxiality of the transducer housing 26 relative to the connecting seat 21, the outer end face of the transducer housing 26, directly or indirectly constrained by the inner side of the clamping flange 22, controls the axial direction and end position of the ultrasonic transducer 2. Since the axial direction and end position constraint are ultimately achieved through the fit between the first and second planes, the thread fit accuracy between the clamping bolt 28 and the connecting seat 21 will not be affected. The uneven deformation of the second elastic ring 25 in the circumferential direction does not need to be considered in terms of its deformation resistance when designing and selecting the second elastic ring 25. Under such structural characteristics, compared with the existing ultrasonic transducer 2 fixing method, a second elastic ring 25 with a smaller outer diameter and a smaller compression amount can be used. This is beneficial for controlling the noise interference of the sensor assembly 27: the smaller compression amount of the second elastic ring 25 can reduce the contact area between the second elastic ring 25 and the connecting seat 21 and the transducer housing 26, which is beneficial for blocking the propagation of surface sound from the flow channel 1.
[0058] Example 4:
[0059] This embodiment is a further refinement of embodiment 3:
[0060] The second elastic ring 25 is installed on the transducer housing 26 through an annular groove on the outer wall of the transducer housing 26. The number of second elastic rings 25 is greater than 1, and they are arranged at intervals on the axis of the transducer housing 26.
[0061] Both the first elastic ring 24 and the second elastic ring 25 are rubber O-rings. This solution provides a technical approach that facilitates the installation of the second elastic ring 25, ensuring axial sealing reliability and maintaining coaxiality accuracy: the second elastic ring 25 is pre-installed on the transducer housing 26, and then embedded in the central hole along with the transducer housing 26; by setting the number of second elastic rings 25 to be greater than one, multiple seals can be formed in the gas leakage direction, reducing the contact area between the second elastic ring 25 and the transducer housing 26 and the connecting seat 21 when the sealing purpose is achieved, thus facilitating noise control. The use of rubber O-rings for the first elastic ring 24 and the second elastic ring 25 also benefits the noise blocking control from the perspective of the acoustic path cross-sectional area.
[0062] Regarding the noise control, a further application is as follows: both the surface of the first elastic ring 24 and the second elastic ring 25 are coated with a Teflon surface layer. The Teflon surface layer is used as the contact layer between the first elastic ring 24 and the connecting seat 21 and / or the transducer housing 26, and the Teflon surface layer is used as the contact layer between the second elastic ring 25 and the connecting seat 21 and / or the transducer housing 26. The material properties of Teflon itself are used to block the sound propagation of the surface, thereby improving the signal acquisition quality of the sensor assembly 27.
[0063] Example 5:
[0064] This embodiment is a further refinement of embodiment 1:
[0065] The outer end face of the transducer housing 26 indirectly acts on the inner end face of the clamping flange 22; it also includes a pad 23 sandwiched between the outer end face of the transducer housing 26 and the inner end face of the clamping flange 22, the pad 23 being a flat pad made of plastic.
[0066] After the clamping bolt 28 is tightened, the outer end face of the transducer housing 26 and the inner end face of the clamping flange 22 are parallel planes to each other, the inner end face of the pad 23 is in contact with the outer end face of the transducer housing 26, and the outer end face of the pad 23 is in contact with the inner end face of the clamping flange 22.
[0067] The transducer housing 26 is spaced apart from the connecting seat 21. In the structure of the ultrasonic flow meter, the ultrasonic transducer 2 is fixed to the connecting seat 21 by bolt connection using clamping bolts 28. Therefore, the connecting seat 21, clamping flange 22, and clamping bolts 28 should preferably be made of metal. From the perspective of noise reduction of the sensor assembly 27, the ultrasonic transducer 2 is spaced apart from the connecting seat 21 (not in direct contact) by using the first elastic ring 24, or the first elastic ring 24 and the second elastic ring 25 working together. The indirect effect is achieved through the pad 23, which can further improve the signal acquisition quality of the sensor assembly 27 by utilizing the blocking effect of the pad 23 on the sound propagation of the meter body. In specific applications, the end faces of both ends of the pad 23 are set to be planes perpendicular to the axis of the end plate, and the second plane is a plane perpendicular to the axis of the clamping flange 22.
[0068] Example 6:
[0069] This embodiment is a further refinement of embodiment 5:
[0070] The inner end face of the clamping flange 22 has a boss, which is embedded in the central hole and acts on the outer end face of the pad 23. This solution aims to provide a watch body structure that is easy to assemble and whose assembly accuracy can be controlled: the boss being embedded in the central hole means that the inner end face of the clamping flange 22 is installed in the central hole. Through the cooperation of this end face with the outer end face of the pad 23, the first elastic ring 24, the ultrasonic transducer 2, and the pad 23 are all recessed and installed in the central hole. In the above process, the hole wall of the central hole can provide lateral support for the corresponding parts to position them. After the above components are assembled, the clamping flange 22 is installed on the outer side of the pad 23 to realize the assembly of the relevant watch body structure.
[0071] Example 7:
[0072] This embodiment is a further refinement of embodiment 5:
[0073] The material of the gasket 23 is Teflon. This solution provides a specific gasket 23 selection. First, the non-stick properties, thermal stability, wear resistance, corrosion resistance, and sliding properties of Teflon itself can be utilized to ensure the smoothness of the corresponding mating surfaces, the dimensional accuracy and positional accuracy of the body structure, and reduce the possibility of the ultrasonic transducer 2 axis deviating from the connecting seat 21 axis due to friction during the assembly of the clamping flange 22. In addition, Teflon is a high-performance sound-blocking material, and this material selection is very beneficial for the gasket 23 to block the sound propagation of the body.
[0074] Example 8:
[0075] This embodiment is a further refinement of embodiment 5:
[0076] Both the pad 23 and the clamping flange 22 are ring-shaped structures with a central hole, and the holes on the pad 23 and the clamping flange 22 are interconnected. This solution provides a technical solution that uses the hole as a wire hole on the structure of this device: the cable led out from the rear end (outer end) of the sensor assembly 27 can be led out through the hole.
[0077] Example 9:
[0078] This embodiment, based on Embodiment 1, provides an ultrasonic flow meter, including the ultrasonic transducer 2 assembly structure described in Embodiment 1. The ultrasonic flow meter includes the ultrasonic transducer 2 assembly structure, representing a specific application of the ultrasonic transducer 2 assembly structure.
[0079] Example 10:
[0080] This embodiment is a further refinement of embodiment 9:
[0081] The flow channel 1 is provided with multiple connecting seats 21, and each connecting seat 21 is equipped with an ultrasonic transducer 2. The ultrasonic transducers 2 form a dual-channel through-beam arrangement or a multi-channel through-beam arrangement. As those skilled in the art know, in the prior art, according to the channel arrangement method, there are single-channel through-beam arrangements, V-shaped reflection arrangements, U-shaped reflection arrangements, and dual (multi)-channel through-beam arrangements. This solution aims to provide a solution that utilizes relevant channel design to achieve a short channel length, suitability for large-diameter flow meters, good repeatability, and high accuracy in the form of a flow meter.
[0082] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, other embodiments derived without departing from the technical solution of the present invention should be included within the scope of protection of the present invention.
Claims
1. An ultrasonic transducer assembly structure, including a flow channel (1), a connecting seat (21) disposed on the flow channel (1), and an ultrasonic transducer (2) mounted on the connecting seat (21). Its features are, The central hole of the connecting seat (21) is a stepped hole, and the stepped hole has a stepped surface facing outward from the central hole; The ultrasonic transducer (2) includes a transducer housing (26), which is supported on the stepped surface by a first elastic ring (24). The outer end face of the connecting seat (21) is a first plane perpendicular to the central hole; It also includes a clamping flange (22), on which a second plane is provided. The clamping flange (22) is fixed to the connecting seat (21) by multiple clamping bolts (28). After the clamping bolts (28) are tightened, the first plane and the second plane are in contact, and the first elastic ring (24) undergoes compressive elastic deformation in the axial direction of the central hole. The outer end face of the transducer housing (26) indirectly acts on the inner end face of the clamping flange (22), and the inner end face of the clamping flange (22) defines the position of the transducer housing (26) on the axis of the central hole and defines the axial direction of the transducer housing (26). It also includes a pad (23) sandwiched between the outer end face of the transducer housing (26) and the inner end face of the clamping flange (22). The pad (23) is a flat pad and the material of the pad (23) is plastic. The outer end of the transducer housing (26) is provided with an annular flange (29), and the first elastic ring (24) is clamped between the stepped surface and the inner end face of the annular flange (29). The transducer housing (26) has a cylindrical structure and the central hole is a circular hole; It also includes a second elastic ring (25) disposed between the wall of the central hole and the outer wall of the transducer housing (26), the second elastic ring (25) serving as an axial seal in the gap between the wall of the central hole and the outer wall of the transducer housing (26).
2. The ultrasonic transducer assembly structure according to claim 1, characterized in that, The second elastic ring (25) is installed on the transducer housing (26) through an annular groove on the outer wall of the transducer housing (26). The number of the second elastic rings (25) is greater than 1. The second elastic rings (25) are arranged at intervals on the axis of the transducer housing (26). Both the first elastic ring (24) and the second elastic ring (25) are rubber O-rings.
3. The ultrasonic transducer assembly structure according to claim 1, characterized in that, After the clamping bolt (28) is tightened, the outer end face of the transducer housing (26) and the inner end face of the clamping flange (22) are parallel planes to each other, the inner end face of the pad (23) is in contact with the outer end face of the transducer housing (26), and the outer end face of the pad (23) is in contact with the inner end face of the clamping flange (22). The transducer housing (26) is spaced apart from the connecting seat (21).
4. The ultrasonic transducer assembly structure according to claim 3, characterized in that, The inner end face of the clamping flange (22) has a boss, which is embedded in the central hole and acts on the outer end face of the pad (23).
5. The ultrasonic transducer assembly structure according to claim 3, characterized in that, The pad (23) is made of Teflon.
6. The ultrasonic transducer assembly structure according to any one of claims 3 to 5, characterized in that, Both the pad (23) and the clamping flange (22) are plate ring structures with a central hole, and the hole on the pad (23) is connected to the hole on the clamping flange (22).
7. An ultrasonic flow meter, characterized in that, Includes the ultrasonic transducer assembly structure as described in any one of claims 1 to 6.
8. The ultrasonic flow meter according to claim 7, characterized in that, The flow channel (1) is provided with multiple connecting seats (21), and each of the connecting seats (21) is equipped with an ultrasonic transducer (2). The ultrasonic transducers (2) form a dual-channel beam-to-beam arrangement or a multi-channel beam-to-beam arrangement.