Transducer for ultrasonic flowmeter

Abstract

The invention relates to the technical field of ultrasonic flow meters, in particular to a transducer for an ultrasonic flow meter, which comprises a transducer head, a shell, a sealing assembly, a connecting line and a lead, the shell is of a cylindrical structure with two open ends, the transducer head is at least partially arranged at one end of the shell, and the sealing assembly and the shell jointly define a sealed accommodating space; the transducer head comprises a protective shell with an opening in one end, a matching layer, a piezoelectric ceramic piece, a backing layer and a rubber ring are arranged in the protective shell, the connecting wire is led out from the upper face and the lower face of the piezoelectric ceramic piece, and acoustic resistance of the protective shell is located between the piezoelectric ceramic piece and gas. According to the invention, step-by-step transition of acoustic impedance is realized, sound wave reflection is effectively reduced, the transmitting efficiency and receiving sensitivity of ultrasonic waves are improved, the signal-to-noise ratio is improved, the accuracy of flow measurement is improved, and meanwhile, the optimized acoustic impedance matching reduces driving energy required by transmitting, reduces energy consumption and is beneficial to prolonging the service life of equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic flowmeters, and in particular to a transducer for an ultrasonic flowmeter. Background Art

[0002] As the core sensing component of ultrasonic flowmeters, the performance of ultrasonic transducers directly affects the stability and reliability of flow measurement. Traditional ultrasonic transducers mainly adopt matching layer exposed structure, ordinary plastic sleeve fully enclosed design, and stainless steel or titanium alloy fully sealed design. However, these solutions all have significant technical limitations: Exposed matching layer structure: Good acoustic impedance matching is achieved through direct contact of the matching layer with the medium, which improves the ultrasonic emission efficiency and the received signal amplitude. However, due to the microporous structure of the matching layer material, water, oil, dust and corrosive gases can easily penetrate into the interior, causing oxidation or corrosion of the piezoelectric ceramic electrodes, thereby shortening the life of the transducer.

[0003] Conventional plastic-sheathed, fully enclosed structures: While the plastic sheath isolates the medium from penetration, addressing corrosion and air leakage, the acoustic impedance of the plastic material differs significantly from that of the piezoelectric ceramic and gas, leading to low acoustic matching efficiency and significantly reduced transducer sensitivity. Furthermore, this increases drive energy consumption, making it difficult to meet the low-power requirements of battery-powered scenarios.

[0004] Stainless steel or titanium alloy fully sealed structure: Fully encapsulating the transducer in stainless steel or titanium alloy effectively prevents the penetration of the medium and improves the transducer's corrosion resistance. However, due to the significant difference in acoustic impedance between stainless steel or titanium alloy and piezoelectric ceramics and gases, the acoustic matching is not ideal, resulting in low ultrasonic transmission efficiency and small received signal amplitude.

[0005] In summary, existing ultrasonic transducers face a contradiction between sealing, acoustic performance, and energy consumption: the exposed matching layer structure is susceptible to medium corrosion and has a high risk of leakage; although the plastic or metal sealing structure enhances protection, the impedance mismatch leads to decreased sensitivity and increased energy consumption, making it difficult to meet the low power consumption and high reliability requirements of battery-powered scenarios.

[0006] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0007] The present invention provides a transducer for an ultrasonic flowmeter, thereby effectively solving the problems pointed out in the background technology.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is: A transducer for an ultrasonic flowmeter, comprising: a transducer head, a housing, a sealing assembly, a connecting wire, and a lead wire; The housing is a cylindrical structure with two ends open, and the transducer head is at least partially disposed at one end of the housing; The sealing assembly is arranged inside the housing, and the sealing assembly, the transducer head and the housing are arranged to form a sealed accommodation space; The connecting wire is arranged in the accommodating space, and one end of the connecting wire is led out from the transducer head, and the other end is connected to the sealing assembly, so as to prevent the gas in the connecting wire from leaking out of the accommodating space; The lead wire is led out from the sealing component and connected to an external device; The transducer head includes a protective shell with an open end, a matching layer, a piezoelectric ceramic sheet, a backing layer sequentially arranged in the protective shell, and a rubber ring arranged between the matching layer, the piezoelectric ceramic sheet and the protective shell, and the connecting wires are led out from the upper and lower surfaces of the piezoelectric ceramic sheet; The acoustic impedance of the protective shell is between the piezoelectric ceramic sheet and the gas.

[0009] Furthermore, the material of the protective shell is one of PDVC, PVDF, and PTFE.

[0010] Furthermore, the protective shell is an integrally formed structure, comprising a cylindrical body and a top wall arranged on the top of the cylindrical body, and the thickness of the top wall is smaller than the thickness of the body.

[0011] Furthermore, the thickness of the top wall is between 0.2 mm and 0.4 mm.

[0012] Furthermore, the top wall is a planar structure.

[0013] Furthermore, the top wall is an inwardly concave arc surface structure.

[0014] Furthermore, the top wall is processed by a laser etching process to ensure the dimensional accuracy of the thickness of the top of the protective shell.

[0015] Furthermore, a rubber sleeve is included, which is arranged between the transducer head and the shell to reduce shock and isolate external mechanical noise.

[0016] Furthermore, the sealing assembly includes a PCB board and a rubber pad arranged above and below, and a T-shaped column passing through the PCB board and the rubber pad. The tail of the connecting wire is arranged at the head of the T-shaped column, and the head of the T-shaped column is sealed by soldering, and the lead is led out from the T-shaped column.

[0017] Furthermore, the inner diameter of the rubber ring matches the outer diameter of the piezoelectric ceramic piece, and the outer diameter is in an interference fit with the inner wall of the protective shell, wrapping the matching layer and the side wall of the piezoelectric ceramic piece in a compression manner.

[0018] The technical solution of the present invention can achieve the following technical effects: The protective housing's acoustic impedance is between that of the piezoelectric ceramic and the gas, achieving a gradual transition in acoustic impedance. This effectively reduces sound wave reflections, improves ultrasonic transmission efficiency and reception sensitivity, enhances the signal-to-noise ratio, and enhances flow measurement accuracy. Furthermore, optimized acoustic impedance matching reduces the drive energy required for transmission, reducing energy consumption. This makes it suitable for low-power applications such as battery-powered devices, helping to extend device life.

[0019] The protective shell is an integrally molded structure with a top wall thickness between 0.2mm and 0.4mm. Preferably, the top wall thickness is 0.3mm, which helps to improve ultrasonic transmittance while maintaining structural strength. The thinner top effectively reduces energy loss in the sound wave propagation path and enhances the sensitivity of ultrasonic transmission and reception. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 Schematic diagram of the structure of a transducer used in an ultrasonic flow meter; Figure 2 Schematic diagram of the transducer head Figure 3 This is a schematic structural diagram of a specific embodiment of the protective shell; Figure 4 It is a structural schematic diagram of another specific embodiment of the protective shell; Figure 5 Schematic diagram of the sealing assembly.

[0022] Figure numerals: 1. transducer head; 11. protective shell; 111. body; 112. top wall; 112a. plane structure; 112b. arc surface structure; 12. matching layer; 13. piezoelectric ceramic sheet; 14. backing layer; 15. rubber ring; 2. shell; 3. sealing assembly; 31. PCB board; 32. rubber pad; 33. T-type column; 34. solder; 4. connecting wire; 5. lead; 6. rubber sleeve. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] like Figures 1 to 5 As shown: A transducer for an ultrasonic flowmeter, comprising: a transducer head 1, a housing 2, a sealing assembly 3, a connecting wire 4 and a lead wire 5; The housing 2 is a cylindrical structure with two ends open, and the transducer head 1 is at least partially disposed at one end of the housing 2; The sealing assembly 3 is arranged inside the housing 2, and the sealing assembly 3, the transducer head 1 and the housing 2 form a sealed accommodation space; The connecting wire 4 is arranged in the accommodation space, and one end of the connecting wire is led out from the transducer head 1, and the other end is connected to the sealing component 3, which is used to prevent the gas in the connecting wire 4 from leaking out of the accommodation space; Lead wire 5 is led out from sealing component 3 and connected to external equipment; The transducer head 1 includes a protective shell 11 with an open end, a matching layer 12, a piezoelectric ceramic plate 13, a backing layer 14, and a rubber ring 15 disposed between the matching layer 12, the piezoelectric ceramic plate 13, and the protective shell 11. The connecting wire 4 is led out from the upper and lower surfaces of the piezoelectric ceramic plate 13. The acoustic impedance of protective shell 11 is positioned between that of piezoelectric ceramic 13 and the gas, achieving a gradual transition in acoustic impedance. This effectively reduces sound wave reflections, improves ultrasonic transmission efficiency and reception sensitivity, enhances the signal-to-noise ratio, and enhances flow measurement accuracy. Furthermore, optimized acoustic impedance matching reduces the drive energy required for transmission, reducing energy consumption. This makes the device suitable for low-power applications such as battery-powered devices, helping to extend the device's lifespan.

[0026] The sealing component 3 and the connecting line 4 work together to form a closed accommodation space, effectively preventing the internal gas of the connecting line 4 from leaking into the external environment, improving the airtightness of the entire machine, and meeting the gas measurement environment with high sealing requirements. It is particularly suitable for flammable and explosive scenarios such as natural gas, and has higher safety.

[0027] In addition, the rubber ring 15 is arranged between the matching layer 12, the piezoelectric ceramic sheet 13 and the protective shell 11, which helps to buffer external vibration and structure-borne noise, reduce mechanical interference, and improve the stability and measurement consistency of the transducer under complex working conditions.

[0028] In this embodiment, matching layer 12, piezoelectric ceramic sheet 13, backing layer 14, and rubber ring 15 are secured within protective housing 11 using a polymer adhesive. This securely bonds the multi-layered assembly and enhances the overall structural stability. The polymer adhesive is heat-resistant and corrosion-resistant. This prevents loosening or falling components due to material aging or adhesive failure. Adhesive attachment facilitates automated batch assembly, improving processing consistency and production efficiency.

[0029] As a preferred embodiment of the above, the material of the protective shell 11 is PDVC (polyvinylidene chloride), PVDF (polyvinyl fluoride), or PTFE (polytetrafluoroethylene). In this embodiment, the material of the protective shell 11 is PDVC. Selecting PDVC, PVDF, or PTFE as the material of the protective shell 11 is conducive to achieving good acoustic impedance matching, making its acoustic impedance between that of piezoelectric ceramics and gas, thereby reducing sound wave reflection, improving transmission efficiency and receiving sensitivity, and enhancing measurement accuracy. At the same time, these polymer materials all have excellent chemical stability and airtightness, which can effectively prevent media such as water, oil, and corrosive gases from penetrating into the interior of the transducer, improving corrosion resistance and extending product service life. In addition, the material has good processability and is suitable for thin shell molding, meeting the transducer's dual requirements for shell 2 thickness and acoustic performance.

[0030] In this embodiment, the protective shell 11 is an integrally molded structure, comprising a cylindrical body 111 and a top wall 112 disposed on top of the cylindrical body 111. The thickness of the top wall 112 is less than that of the body 111. The integrally molded structure of the protective shell 11 eliminates the weak points of seams or welds found in traditional spliced shells, significantly enhancing the overall mechanical strength and preventing the risk of cracks or breakage caused by stress concentration. Furthermore, the design of the top wall 112 being thinner than the thickness of the cylindrical body 111 optimizes the transmission of sound waves, reduces energy loss, and improves the transmission efficiency and reception sensitivity of ultrasonic waves. This structure achieves excellent acoustic response characteristics while ensuring overall strength, enhancing the measurement accuracy and reliability of the transducer.

[0031] The thickness of the top wall 112 is between 0.2 mm and 0.4 mm, preferably 0.3 mm, which helps to improve the transmittance of ultrasound while maintaining structural strength. The thinner top effectively reduces energy loss in the sound wave propagation path, enhances the sensitivity of ultrasound transmission and reception, and further improves the detection accuracy and signal-to-noise ratio of the transducer. In addition, thickness consistency control also helps to stabilize the frequency response of the transducer, improving product consistency and reliability.

[0032] like Figure 3 As shown, as a specific implementation of the protective shell 11, the top wall 112 is a planar structure 112a, which has a simple structure, is easy to process, and is convenient for controlling thickness consistency, thereby enhancing product consistency and manufacturability.

[0033] like Figure 4 As shown, another specific embodiment of the protective housing 11 is shown in which the top wall 112 has an inwardly concave curved surface structure 112b. Specifically, the concave curved surface structure 112b helps focus ultrasound waves, improving the directionality and concentration of sound energy transmission, thereby enhancing transmission efficiency and receiving sensitivity. The curved surface structure 112b also reduces the diffraction effect of sound waves at the edges, optimizes the sound field distribution, and further improves measurement stability and accuracy.

[0034] As a preferred embodiment of the above embodiment, the top wall 112 is processed using a laser etching process to ensure the dimensional accuracy of the thickness of the top of the protective shell 11. Specifically, the use of a laser etching process to precisely process the top of the protective shell 11 helps to accurately control the thickness of the top, ensuring its dimensional accuracy and consistency. Improved thickness accuracy can further optimize the transmission characteristics of sound waves, making the transmission frequency and receiving sensitivity more stable, and improving the performance consistency and measurement accuracy of the transducer. In addition, this process is non-contact and highly controllable, suitable for thin film materials, and improves production efficiency and product yield.

[0035] In this embodiment, continue to refer to Figure 1 The transducer head 1 also includes a rubber sleeve 6, which is disposed between the transducer head 1 and the housing 2 to reduce vibration and isolate external mechanical noise. The rubber sleeve 6 encases the transducer head 1, preventing direct contact with the metal housing. This provides a vibration-reducing and noise-isolating function. This is particularly important in applications involving voltage-regulating equipment, where noise levels are high. Noise isolation significantly improves the subsequent circuitry's processing of ultrasonic signals, thereby enhancing the stability and reliability of the overall measurement system.

[0036] Since there is a possibility of air leakage in the gap between the connecting wire 4 and the epoxy resin seal of the outer layer of the connecting wire 4, air leakage may occur, which is unacceptable in an environment with explosive gases such as fuel gas. Therefore, the following improvements are made: Among them, such as Figure 5As shown, the sealing assembly 3 includes a PCB board 31 and a rubber pad 32 arranged above and below, as well as a T-shaped post 33 extending through the PCB board 31 and the rubber pad 32. The tail of the connecting wire 4 is located at the head of the T-shaped post 33 and sealed with solder 34. The lead 5 extends from the T-shaped post 33. The T-shaped post 33 is made of copper or a copper alloy, which has good conductivity and solderability. By securing the tail of the connecting wire 4 to the head of the T-shaped post 33 and sealing it with solder 34, air leakage caused by gaps between the connecting wire 4 and the epoxy resin can be effectively avoided. Furthermore, the connecting wire 4 is led out through the T-shaped post 33 soldered to the PCB board 31, and the rubber pad 32 below the PCB board 31 is tightly connected to the metal housing 2, further enhancing the airtightness of the sealing assembly 3. This structure is particularly suitable for use in explosive gas environments, such as gas, where sealing is extremely demanding, helping to eliminate safety hazards and improve the reliability and safety of system operation.

[0037] As a preferred embodiment of the above embodiment, the inner diameter of the rubber ring 15 matches the outer diameter of the piezoelectric ceramic piece 13, and the outer diameter is in an interference fit with the inner wall of the protective shell 11, wrapping the matching layer 12 and the side wall of the piezoelectric ceramic piece 13 in a compression manner, effectively improving the fixing stability of the component and preventing displacement or loosening caused by vibration or impact; at the same time, this structure can absorb lateral stress and suppress the propagation of mechanical noise, further improving the anti-interference ability and signal-to-noise ratio of the transducer; in addition, the rubber ring 15 in a compressed state can also enhance the sealing, prevent external gas or liquid from penetrating, and improve the durability and reliability of the overall system.

[0038] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A transducer for an ultrasonic flowmeter, characterized in that: include: Transducer head, housing, sealing assembly, connecting wires and leads; The housing is a cylindrical structure with two ends open, and the transducer head is at least partially disposed at one end of the housing; The sealing assembly is arranged inside the housing, and the sealing assembly, the transducer head and the housing are arranged to form a sealed accommodation space; The connecting wire is arranged in the accommodating space, and one end of the connecting wire is led out from the transducer head, and the other end is connected to the sealing assembly, so as to prevent the gas in the connecting wire from leaking out of the accommodating space; The lead wire is led out from the sealing component and connected to an external device; The transducer head includes a protective shell with an open end, a matching layer, a piezoelectric ceramic sheet, a backing layer sequentially arranged in the protective shell, and a rubber ring arranged between the matching layer, the piezoelectric ceramic sheet and the protective shell, and the connecting wires are led out from the upper and lower surfaces of the piezoelectric ceramic sheet; The acoustic impedance of the protective shell is between the piezoelectric ceramic sheet and the gas.

2. The transducer for an ultrasonic flowmeter according to claim 1, characterized in that: The material of the protective shell is one of PDVC, PVDF, and PTFE.

3. The transducer for an ultrasonic flowmeter according to claim 1, characterized in that: The protective shell is an integrally formed structure, comprising a cylindrical body and a top wall arranged on the top of the cylindrical body, and the thickness of the top wall is smaller than the thickness of the body.

4. The transducer for an ultrasonic flowmeter according to claim 3, characterized in that: The thickness of the top wall is between 0.2 mm and 0.4 mm.

5. The transducer for an ultrasonic flowmeter according to claim 3, characterized in that: The top wall is a planar structure.

6. The transducer for an ultrasonic flowmeter according to claim 3, characterized in that: The top wall is an inwardly concave arc surface structure.

7. The transducer for an ultrasonic flowmeter according to claim 3, characterized in that: The top wall is processed by a laser etching process to ensure the dimensional accuracy of the thickness of the top of the protective shell.

8. The transducer for an ultrasonic flowmeter according to claim 1, characterized in that: It also includes a rubber sleeve, which is arranged between the transducer head and the shell and is used for shock absorption and isolation of external mechanical noise.

9. The transducer for an ultrasonic flowmeter according to claim 1, characterized in that: The sealing assembly includes a PCB board and a rubber pad arranged above and below, and a T-shaped column passing through the PCB board and the rubber pad. The tail of the connecting wire is arranged at the head of the T-shaped column, and the head of the T-shaped column is sealed by soldering, and the lead is led out from the T-shaped column.

10. The transducer for an ultrasonic flowmeter according to claim 8, characterized in that: The inner diameter of the rubber ring matches the outer diameter of the piezoelectric ceramic piece, and the outer diameter is in an interference fit with the inner wall of the protective shell, wrapping the matching layer and the side wall of the piezoelectric ceramic piece in a compression manner.

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