Ultrasonic transducer for gas metering and gas meter
Patent Information
- Application Number
- CN202611146808.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-30
- Publication Date
- 2026-10-20
AI Technical Summary
现有的一些超声换能器采用块体压电陶瓷(如PZT)制备，存在体积大、与气体声阻抗匹配差、难以实现阵列化及批量制造等问题
[0016]本申请通过传感模块与MEMS超声换能模块的高度集成，减小超声换能器的体积，契合燃气计量场景中超声换能器的小型化需求；通过超表面格栅结构在提供物理防护的基础上进一步对穿过其的超声波进行相位调制以优化声场，实现超声波束的聚焦、偏转或旁瓣抑制，从而提高了超声换能器的信噪比；通过传感模块的多维信号集成，实现燃气管道中气流的多参数一体化测量。
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Abstract
Description
Technical Field
[0001] This application relates to the field of acoustic measurement technology, and in particular to ultrasonic transducers and gas meters for gas metering. Background Technology
[0002] Ultrasonic gas meters are widely used in both residential and industrial gas metering due to their advantages such as no moving mechanical parts, wide range, and high metering accuracy. However, some existing ultrasonic transducers are made of bulk piezoelectric ceramics (such as PZT), which suffer from problems such as large size, poor acoustic impedance matching with the gas, and difficulty in arraying and mass production. Since gas metering typically requires compensation for temperature and pressure in the gas pipeline to calculate the standard flow rate, using separate ultrasonic transducers, temperature sensors, and pressure sensors results in a complex meter structure, numerous flow channel openings, poor assembly consistency, and potential leakage risks.
[0003] Furthermore, the inventors discovered in practical applications that the internal environment of gas pipelines is complex, with airflow often containing dust, water vapor, or oil. When ultrasonic transducers are directly exposed to the flow field, they are easily damaged or accumulate deposits, thus altering the acoustic characteristics of the ultrasonic transducers and leading to inaccurate measurements. While some existing metal mesh or porous plate structures provide some physical protection, they also cause severe attenuation of ultrasonic signals and distortion of the sound field. Summary of the Invention
[0004] In view of this, the purpose of this application is to provide an ultrasonic transducer and gas meter for gas metering, which realizes miniaturization, high signal-to-noise ratio and multi-parameter integrated measurement of the ultrasonic transducer for gas metering.
[0005] To achieve the above objectives, this application provides the following technical solution.
[0006] In a first aspect, this application provides an ultrasonic transducer for gas metering, comprising: a substrate having a first end face and a second end face disposed opposite to each other; a MEMS ultrasonic transducer module disposed on the first end face of the substrate; a sensing module disposed on the first end face of the substrate, the sensing module and the MEMS ultrasonic transducer module being spaced apart and electrically connected; and a housing having an internal cavity structure, the substrate, the MEMS ultrasonic transducer module and the sensing module being located inside the housing, the housing being fixedly connected to the second end face of the substrate, and a metasurface grid structure being provided on the top of the housing, the metasurface grid structure being located above the MEMS ultrasonic transducer module.
[0007] Optionally, the MEMS ultrasonic transducer module is configured as a PMUT array, and the operating frequency f of the MEMS ultrasonic transducer module is... w The range is: 400kHz≤f w ≤2MHz.
[0008] Optionally, the sensing module is configured as any one of a temperature sensor, a pressure sensor, or a temperature-pressure composite sensor.
[0009] Optionally, the sensing module and the MEMS ultrasonic transducer module are integrated on the first end face of the substrate based on SiP technology, or are monolithically integrated on the first end face of the substrate.
[0010] Optionally, the metasurface grid structure is configured to include multiple acoustic units with subwavelength characteristic dimensions, and the metasurface grid structure is configured to phase modulate ultrasonic waves passing through it.
[0011] Optionally, the substrate is configured as a circuit board.
[0012] Optionally, the ultrasonic transducer for gas metering further includes: solder joints, wherein there are multiple solder joints, and the multiple solder joints are spaced apart between the second end face of the substrate and the outer shell.
[0013] Optionally, the vertical cross-sectional shape of the solder joint is semi-circular, the horizontal end face of the solder joint is fixedly connected to the second end face of the substrate, and the arc end face of the solder joint is fixedly connected to the outer shell.
[0014] Optionally, the ultrasonic transducer for gas metering further includes: a plurality of sealing plates, wherein the plurality of sealing plates are configured as a frame-shaped structure surrounding the bottom of the housing.
[0015] Secondly, embodiments of this application provide a gas meter applied to a gas pipeline, the gas pipeline including a main flow channel and a bypass flow channel arranged in the same direction and parallel to the main flow channel, the gas meter including: an ultrasonic transducer for gas metering as described in the first aspect or any optional embodiment of the first aspect, the ultrasonic transducer for gas metering being installed in the bypass flow channel.
[0016] This application reduces the size of the ultrasonic transducer by highly integrating the sensing module and the MEMS ultrasonic transducer module, meeting the miniaturization requirements of ultrasonic transducers in gas metering scenarios; by using a metasurface grid structure to provide physical protection and further modulate the phase of the ultrasonic waves passing through it to optimize the sound field, it achieves focusing, deflection or sidelobe suppression of the ultrasonic beam, thereby improving the signal-to-noise ratio of the ultrasonic transducer; and by integrating the multi-dimensional signals of the sensing module, it realizes the integrated measurement of multiple parameters of airflow in gas pipelines. Attached Figure Description
[0017] The present application will be further described below with reference to the accompanying drawings and embodiments.
[0018] Figure 1 This is a schematic diagram of the top structure of an ultrasonic transducer for gas metering provided in an embodiment of this application.
[0019] Figure 2 for Figure 1 A cross-sectional view of an ultrasonic transducer used for gas metering.
[0020] Figure 3 This is a schematic diagram of a first partial cross-sectional structure of the metasurface grid structure provided in the embodiments of this application.
[0021] Figure 4 This is a schematic diagram of a second partial cross-sectional structure of the metasurface grid structure provided in the embodiments of this application.
[0022] Figure 5 This is a schematic diagram of the bottom structure of an ultrasonic transducer for gas metering provided in an embodiment of this application.
[0023] Figure labeling: 1-Outer shell; 2-Metasurface grid structure; 20-Acoustic unit; 3-Sensing module; 4-MEMS ultrasonic transducer module; 5-Substrate; 6-Solder joint; 7-Sealing sheet. Detailed Implementation
[0024] The present application will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present application, and therefore only show the components relevant to the present application.
[0025] See Figures 1-5 This application provides an ultrasonic transducer for gas metering, including a substrate 5, a MEMS (Micro-Electro-Mechanical System) ultrasonic transducer module 4, a sensing module 3, and a housing 1.
[0026] The substrate 5 has a first end face and a second end face arranged opposite each other. The MEMS ultrasonic transducer module 4 and the sensing module 3 are both disposed on the first end face of the substrate 5. The MEMS ultrasonic transducer module 4 is used to transmit and receive ultrasonic signals, and the sensing module 3 is used to collect the airflow parameters of the gas pipeline. The sensing module 3 and the MEMS ultrasonic transducer module 4 are arranged at intervals, and the sensing module 3 and the MEMS ultrasonic transducer module 4 are electrically connected to transmit signals.
[0027] The interior of the outer shell 1 is a cavity structure. The substrate 5, the MEMS ultrasonic transducer module 4 and the sensing module 3 are located inside the outer shell 1. The outer shell 1 is fixedly connected to the second end face of the substrate 5.
[0028] Based on the above technical solution, the sensing module 3 and the MEMS ultrasonic transducer module 4 are disposed on the same substrate 5 and encapsulated in the same housing 1, which reduces the volume of the ultrasonic transducer and meets the miniaturization requirements of the ultrasonic transducer in the gas metering scenario.
[0029] The top of the outer shell 1 is provided with a metasurface grid structure 2, which is located above the MEMS ultrasonic transducer module 4.
[0030] Understandably, after the ultrasonic transducer is installed in the gas pipeline, the metasurface grid structure 2, as the outermost surface of the encapsulated MEMS ultrasonic transducer module 4, comes into contact with the gas medium. The grid-shaped physical gaps, after being designed to prevent dust and oil contamination, can prevent large particles of impurities, rust, or water droplets in the gas pipeline from directly impacting the surface of the MEMS ultrasonic transducer module 4, thus playing a role in physical protection.
[0031] In some embodiments, the MEMS ultrasonic transducer module 4 is constructed as a PMUT (Piezoelectric Micromachined Ultrasonic Transducer) array, and the operating frequency f of the MEMS ultrasonic transducer module 4 is... w The range is: 400kHz≤f w ≤2MHz.
[0032] The PMUT array consists of multiple non-axisymmetric thin-film array elements, with the minor axis of the array elements parallel to the gas flow direction in the gas pipeline, in order to optimize the coverage of the sound beam within the cross-section of the gas pipeline and improve the accuracy of gas velocity measurement.
[0033] In practical applications, PMUT arrays can be constructed as suspended micro-film structures formed by etching high-performance piezoelectric thin film materials (such as AlScN, scandium aluminum nitride) on a silicon substrate. Compared with bulk piezoelectric ceramics, their acoustic impedance is better matched with gaseous media such as natural gas, thus having higher energy coupling efficiency.
[0034] It should be noted that the operating frequency f of the MEMS ultrasonic transducer module 4 is... w The resonant frequency f of the MEMS ultrasonic transducer module 4 indicates the frequency at which it transmits or receives ultrasonic waves. r This indicates the frequency at which its sound-to-electric energy conversion efficiency is at its highest.
[0035] Ideally, when the MEMS ultrasonic transducer module 4 is constructed as a PMUT array, the operating frequency f w Equal to the resonant frequency f r At this point, the MEMS ultrasonic transducer module 4 achieves optimal transmission efficiency and reception sensitivity for ultrasonic waves.
[0036] In practical applications, the resonant frequency f of the MEMS ultrasonic transducer module 4 r The range is: 450kHz≤f r ≤500kHz, to balance the acoustic attenuation in the gas medium and the measurement time resolution.
[0037] In some implementations, the sensing module 3 is configured as any one of a temperature sensor, a pressure sensor, or a temperature-pressure composite sensor.
[0038] In practical applications, the pressure sensing element used in the pressure sensor can be configured as a piezoresistive or capacitive MEMS pressure chip, the temperature sensing element used in the temperature sensor can be configured as a platinum resistance temperature detector or a thermistor, and the temperature-pressure composite sensor can be configured as an integration of the above-mentioned pressure sensing element and the above-mentioned temperature sensing element.
[0039] Based on the above technical solution, the multi-parameter integrated measurement of gas flow in the gas pipeline is realized through the multi-dimensional signal integration of the sensing module 3, so as to correct the standard volume of gas flow in the gas pipeline.
[0040] In some implementations, the sensing module 3 and the MEMS ultrasonic transducer module 4 are integrated on the first end face of the substrate 5 based on SiP (System in Package) technology, or are monolithically integrated on the first end face of the substrate 5.
[0041] For example, in SiP integration, the sensing module 3 and the MEMS ultrasonic transducer module 4 are integrated in the same housing and share the same electrical interface to output ultrasonic ToF (Time of Flight) signals as well as temperature analog / digital signals and / or pressure analog / digital signals.
[0042] For example, in monolithic integration, the sensing module 3 and the MEMS ultrasonic transducer module 4 are integrated in the non-vibration region of the same silicon substrate.
[0043] It is understandable that if the sensing module 3 is constructed as a temperature-pressure composite sensor, the pressure sensing element and temperature sensing element configured in the temperature-pressure composite sensor can be integrated with the MEMS ultrasonic transducer module 4 based on SiP technology or integrated on a single chip.
[0044] Based on the above technical solution, the sensing module 3 and the MEMS ultrasonic transducer module 4 are highly integrated, achieving the ultimate miniaturization effect.
[0045] In some embodiments, the metasurface grid structure 2 is configured to include multiple subwavelength characteristic dimensions of acoustic units 20, and the metasurface grid structure 2 is configured to phase modulate ultrasonic waves passing through it.
[0046] Specifically, multiple acoustic units 20 with subwavelength characteristic dimensions are arranged according to a specific pattern to form a subwavelength scale structure (such as a labyrinth structure of different depths or a Helmholtz resonant cavity). When ultrasonic waves from 400 kHz to 2 MHz pass through the metasurface grid structure 2, the phase modulation of the arrayed local acoustic units 20 causes the ultrasonic waves to generate a preset phase shift, thereby achieving directional deflection, focusing, or impedance matching conversion of the ultrasonic beam. This allows the ultrasonic waves emitted from the MEMS ultrasonic transducer module 4 to be injected into the flow channel at the optimal angle, suppressing sidelobe interference and reducing multipath noise caused by reflection from the pipe wall.
[0047] As a preferred implementation method, see [link to relevant documentation]. Figure 3 The vertical cross-sectional shape of the acoustic unit 20 is an isosceles trapezoid with a base angle α ranging from 65° to 90°, in order to optimize the ultrasonic emission sound field of the MEMS ultrasonic transducer module 4.
[0048] As another preferred implementation method, see [link to documentation]. Figure 4 The vertical cross-sectional shape of the acoustic unit 20 is an isosceles trapezoid with a base angle β ranging from 90° to 115°, in order to optimize the ultrasonic receiving sound field of the MEMS ultrasonic transducer module 4.
[0049] In practical applications, the thickness of the acoustic unit 20, i.e. the thickness h of the top of the metasurface grid structure 2, is preferably in the range of 100μm≤h≤400μm.
[0050] Based on the above implementation, the metasurface grid structure 2 further modulates the phase of the ultrasonic waves passing through it to optimize the sound field, thereby achieving focusing, deflection or sidelobe suppression of the ultrasonic beam and thus improving the signal-to-noise ratio of the ultrasonic transducer.
[0051] In some embodiments, the substrate 5 is configured as a circuit board to achieve electrical coupling between the sensing module 3 and the MEMS ultrasonic transducer module 4.
[0052] In some embodiments, the ultrasonic transducer for gas metering further includes: solder joints 6, wherein there are multiple solder joints 6, which are spaced apart between the second end face of the substrate 5 and the outer shell 1.
[0053] Based on the above technical solution, a low-impedance conductive path is established between the substrate 5 and the outer shell 1 using solder joint 6, thereby releasing high-frequency noise and static electricity in the circuit when the substrate 5 is constructed as a circuit board, and playing the role of electromagnetic shielding.
[0054] In some embodiments, the vertical cross-sectional shape of solder joint 6 is semi-circular, the horizontal end face of solder joint 6 is fixedly connected to the second end face of substrate 5, and the arc end face of solder joint 6 is fixedly connected to outer shell 1.
[0055] In other words, the three-dimensional shape of solder point 6 is hemispherical, which has a larger cross-sectional area compared with electrical connection methods such as bonding wire. During the welding process, it forms a gentle current density gradient, allowing the current to flow more evenly across the welding surface and uniformly transferring external stress to the entire spherical surface. This results in stronger fatigue resistance and improves the reliability of the electrical connection between the substrate 5 and the shell 1.
[0056] In some embodiments, the ultrasonic transducer for gas metering further includes: a plurality of sealing plates 7, wherein the plurality of sealing plates 7 are configured as a frame-shaped structure surrounding the bottom of the housing 1.
[0057] In practical applications, a hole-like structure can be made on the sealing plate 7, and the bottom of the outer shell 1 can be fixed to the gas pipeline by using the hole-like structure in conjunction with the external fixing components; alternatively, the sealing plate 7 can be constructed as a solder pad, and the bottom of the outer shell 1 can be fixed to the gas pipeline by soldering.
[0058] This application also provides a gas meter applied to a gas pipeline, the gas pipeline including a main flow channel and a bypass flow channel arranged in the same direction as the main flow channel, the gas meter including the ultrasonic transducer for gas metering as described in any of the above embodiments, the ultrasonic transducer for gas metering being installed in the bypass flow channel.
[0059] Understandably, in a gas pipeline with a main flow path and a bypass flow path, the gas mainly flows through the main flow path, while a small portion of the warmer, cleaner gas is diverted into the narrow bypass flow path.
[0060] Based on the above technical solution, an ultrasonic transducer for gas metering is used to measure the stable flow of gas in the bypass channel, so as to balance and compensate the gas flow in the main channel and ensure the measurement accuracy of the gas meter.
[0061] In this embodiment, the acoustic measurement method of the MEMS ultrasonic transducer module 4, the temperature or pressure parameter measurement method of the sensing module 3, and the electrical signal transmission method between the MEMS ultrasonic transducer module 4 and the sensing module 3 are technologies well known to those skilled in the art, and therefore will not be explained in detail.
[0062] The above embodiments are only for illustrating the technical concept and features of this application. Their purpose is to enable those skilled in the art to understand the content of this application and implement it. They should not be used to limit the scope of protection of this application. All equivalent changes or modifications made in accordance with the spirit and essence of this application should be covered within the scope of protection of this application.
Claims
1. An ultrasonic transducer for gas metering, characterized in that, include: The substrate (5) has a first end face and a second end face disposed opposite to each other; MEMS ultrasonic transducer module (4), wherein the MEMS ultrasonic transducer module (4) is disposed on the first end face of the substrate (5); The sensing module (3) is disposed on the first end face of the substrate (5). The sensing module (3) and the MEMS ultrasonic transducer module (4) are arranged at intervals. The sensing module (3) and the MEMS ultrasonic transducer module (4) are electrically connected. The outer shell (1) has a cavity structure inside. The substrate (5), the MEMS ultrasonic transducer module (4) and the sensing module (3) are located inside the outer shell (1). The outer shell (1) is fixedly connected to the second end face of the substrate (5). A metasurface grid structure (2) is provided on the top of the outer shell (1). The metasurface grid structure (2) is located above the MEMS ultrasonic transducer module (4).
2. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The MEMS ultrasonic transducer module (4) is constructed as a PMUT array, and the operating frequency of the MEMS ultrasonic transducer module (4) is f. w The range is: 400kHz≤f w ≤2MHz.
3. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The sensing module (3) is constructed as any one of a temperature sensor, a pressure sensor, or a temperature-pressure composite sensor.
4. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The sensing module (3) and the MEMS ultrasonic transducer module (4) are integrated on the first end face of the substrate (5) based on SiP technology, or are integrated on the first end face of the substrate (5) as a single piece.
5. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The metasurface grid structure (2) is constructed as an acoustic unit (20) comprising multiple subwavelength characteristic dimensions, and the metasurface grid structure (2) is configured to phase modulate ultrasonic waves passing through it.
6. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The substrate (5) is constructed as a circuit board.
7. The ultrasonic transducer for gas metering according to claim 6, characterized in that, The ultrasonic transducer for gas metering further includes: solder joints (6), the number of which is multiple, and the multiple solder joints (6) are spaced apart between the second end face of the substrate (5) and the outer shell (1).
8. The ultrasonic transducer for gas metering according to claim 7, characterized in that, The vertical cross-sectional shape of the solder joint (6) is semi-circular. The horizontal end face of the solder joint (6) is fixedly connected to the second end face of the substrate (5). The arc end face of the solder joint (6) is fixedly connected to the outer shell (1).
9. The ultrasonic transducer for gas metering according to claim 1, characterized in that, The ultrasonic transducer for gas metering further includes: a sealing plate (7), wherein there are multiple sealing plates (7), and the multiple sealing plates (7) are constructed as a frame-shaped structure surrounding the bottom of the outer shell (1).
10. A gas meter applied to a gas pipeline, the gas pipeline comprising a main flow channel and a bypass flow channel arranged in the same direction and parallel to the main flow channel, characterized in that, The gas meter includes: The ultrasonic transducer for gas metering as described in any one of claims 1-9, wherein the ultrasonic transducer for gas metering is installed in the bypass channel.