CN219092637U

CN219092637U - Ultrasonic transducer structure

Info

Publication number: CN219092637U
Application number: CN202222278478.3U
Authority: CN
Inventors: 朴奇焕
Original assignee: Beijing Weien Sensing Technology Co ltd
Current assignee: Beijing Weien Sensing Technology Co ltd
Priority date: 2022-08-29
Filing date: 2022-08-29
Publication date: 2023-05-30
Anticipated expiration: 2032-08-29

Abstract

The utility model discloses an ultrasonic transducer structure, and relates to the technical field of transducers. The device comprises a shell, a crystal oscillator piece, a wafer gland, a belleville spring, a gland nut, a wire, a sealing ring and a transducer fixing head, wherein the crystal oscillator piece is arranged in the shell, the wafer gland is arranged on the crystal oscillator piece, the belleville spring and the gland nut are sequentially arranged on the wafer gland, and a coupling agent is poured between the crystal oscillator piece and the shell; the crystal oscillator piece is connected with a wiring pole at the center of the transducer fixing head through a wire, the wiring pole is connected with a cable joint, and a sealing ring is arranged between the shell and the transducer fixing head and is connected with the shell through threads. The utility model has reasonable structural design and good packaging effect, can stably work for a long time under the high temperature environment of 200 ℃ and can work for a long time under the environment of 4.0 MPa.

Description

Ultrasonic transducer structure

Technical Field

The utility model relates to the technical field of transducers, in particular to an ultrasonic transducer structure.

Background

Compared with differential pressure type meters, volumetric meters, traditional speed type meters and the like, the ultrasonic flowmeter has the advantages of large caliber range, wide range ratio, intelligence, easy installation, low cost, high precision, long service life, low cost maintenance and the like. The ultrasonic flowmeter is divided into a liquid ultrasonic flowmeter and a gas ultrasonic flowmeter from a measuring medium, and is divided into urban water diversion engineering measurement and municipal water supply and drainage (raw water, tap water, purified water, reclaimed water and sewage) measurement from industry; metering industrial water (desalted water, circulating water and sewage); metering agricultural water (farmland irrigation water, drinking water and sewage); natural gas high-low pressure pipeline, province and city grade distribution station metering and city gas metering; natural gas coal mining, liquefied natural gas and liquefied petroleum gas metering; metering large industrial gas; metering blast furnace gas and coke oven gas; other energy-saving and emission-reducing gas discharge metering and the like.

Ultrasonic flowmeter installations can be categorized as standard pipe sections (flanged connections), plug-in, external clamps, etc. However, no matter what the form is, the problems of the installation form, performance index, reliability and interchangeability of the transducer are solved, and the quality of the performance index of the transducer directly influences the measurement precision, reliability and interchangeability of the flowmeter.

The function of an ultrasonic transducer is to transmit and receive ultrasonic signals, i.e. to convert electrical energy into mechanical energy and then mechanical energy into acoustic energy when transmitting signals. When receiving signals, the acoustic energy is converted into mechanical energy and then the mechanical energy is converted into electric energy, so the transducer is called.

The structure, processing and packaging technology of the ultrasonic transducer directly influence the performance and quality of the transducer. The main performance indexes of the ultrasonic transducer are as follows: the diameter of the transmitting end face of the transducer is small, the interchangeability is good, the structure is reasonable (the installation is convenient), the high temperature and high pressure resistance and the corrosion resistance are realized on the same transmitting distance. The signal characteristic parameters of the ultrasonic transducer include frequency ƒ and sound velocity, and wavelength lambda, and their relationship is ƒ =c/lambda, see fig. 1. The wave intensity of the transducer varies with the transducer emission angle (off-axis angle of the emitted signal waveform), with the smaller the emission angle, the narrower the emitted waveform and the more concentrated the wave intensity.

Waveforms for 3 different transducer emission end radii α and wavelength ratios are shown in fig. 2. The higher the frequency, the shorter the wavelength and the straighter the ultrasonic path. When the wavelength is far smaller than the radius (lambda « alpha) of the transducer, the obtained narrow and powerful sound wave has the advantages that the wave intensity is concentrated when the wave is narrower than the wave, the emission distance is far, false reflection signals are not generated, and the sound channel is more accurate.

At present, the ultrasonic transducer commonly used in domestic engineering mainly adopts materials such as stainless steel, brass, PE and the like for the shell.

The main problems are that the radius alpha of the transmitting end face of the transducer is larger, the matching with frequency and wavelength is not proper, the thickness and flatness consistency of the transmitting surface of the shell are poor, and the interchangeability of the transducer is poor.

In the aspect of packaging, the contact part of the crystal oscillator piece and the shell mostly adopts an adhesive mode, and when the temperature change gradient is large, the phenomenon of falling off or poor contact is generated due to the difference of expansion coefficients of respective materials, so that the signal of the transducer is weakened or the transducer cannot work normally.

At present, the common energy converter in engineering is not isolated from the meter body in an insulating way, so that interference signals from a pipeline and the surrounding environment enter a measuring loop through the energy converter, and the signals of the flowmeter are interfered and cannot be measured normally. The transducers are isolated from the meter body after installation.

In summary, the present utility model provides an ultrasonic transducer structure.

Disclosure of Invention

Aiming at the defects existing in the prior art, the utility model aims to provide an ultrasonic transducer structure which has reasonable structural design and good packaging effect, can stably work for a long time in a high-temperature environment of 200 ℃ and can work for a long time in an environment of 4.0 MPa.

In order to achieve the above object, the present utility model is realized by the following technical scheme: an ultrasonic transducer structure comprises a shell, a crystal oscillator piece, a wafer gland, a disc spring, a gland nut, a wire, a sealing ring and a transducer fixing head, wherein the crystal oscillator piece is arranged in the shell, the wafer gland is arranged on the crystal oscillator piece, the disc spring and the gland nut are sequentially arranged on the wafer gland, and a coupling agent is filled between the crystal oscillator piece and the shell; the crystal oscillator piece is connected with a wiring pole at the center of the transducer fixing head through a wire, the wiring pole is connected with a cable joint, and a sealing ring is arranged between the shell and the transducer fixing head and is connected with the shell through threads.

Preferably, a thread sealant is further arranged at the threaded connection part of the shell and the transducer fixing head.

Preferably, the shell is made of stainless steel 316L or PE, and the diameters of the transducers are 15mm, 20mm and 25mm respectively.

Preferably, the emission angle of the shell is less than or equal to 5 degrees, and the thickness of the emission surface of the shell is 2.82mm.

An ultrasonic transducer packaging method comprising the steps of:

1. and purchasing a qualified bar according to the requirements of a design drawing, and controlling deviation strictly according to machining deviation of each part on the drawing, and verticality, flatness and smoothness of an emission section of the transducer shell.

2. The transducer shell and the transducer fixing head are in threaded connection, a sealing surface on the shell is perpendicular to the axis, the length requirement is guaranteed by connecting threaded threads, and the sealing gasket is made of different materials according to different temperatures, different pressures and different media.

3. The transducer head adopts a brass chromeplating process, and the cable lead of the crystal oscillator piece and the transducer shell adopt an insulation structure design, so that the processing precision and the smoothness are ensured.

4. The crystal vibration plate of the energy converter is tightly pressed by adopting a two-plate disc spring pressing mode, the crystal vibration plate and the emitting surface of the shell adopt a high-temperature resistant couplant, and the back part of the spring locking screw to the inside of the energy converter connector adopts a sealant filling process, so that the couplant is prevented from leaking and the waterproof problem is prevented.

The utility model ensures the signal intensity and interchangeability of the transducer by accurately designing and processing the structural size of the transducer. The product with good interchangeability has no drift of zero point after the transducer is replaced, no recalibration is needed, and great convenience is brought to the on-line maintenance of the flowmeter. The crystal oscillator sheet and the shell adopt a mode of filling a coupling agent and extruding and fixing by using a spring, and a mode of bonding by using glue is not used, so that the problems that when the temperature change gradient is large, the expansion coefficient of each material is not communicated, the phenomenon of falling or poor contact is generated, and the signal of the transducer is weakened or the transducer cannot work normally are avoided.

The utility model has the beneficial effects that: the 15mm/20mm/25mm transducers with different specifications are respectively used on ultrasonic flow meters with the diameters of DN300/DN1200/DNDN3000, the pressure level is 1.0 MPa-2.5 MPa, and the temperature range is not higher than 150 ℃. The installation mode is a standard pipe section flange connection type and field hole installation type. The number of channels of a common ultrasonic flowmeter is 1-5, and each channel consists of a pair of (two) transducers, so that the demand of the transducers is obvious. The transducer has good interchangeability, good insulativity and strong practicability.

Drawings

The utility model is described in detail below with reference to the drawings and the detailed description;

FIG. 1 is a schematic diagram showing the relationship between the characteristic parameters of the signal of an ultrasonic transducer of the background art, including frequency ƒ and sound velocity c and wavelength lambda;

FIG. 2 is a graph of the radius, frequency, and wavelength relationships of an ultrasonic probe in the background of the utility model;

fig. 3 is a schematic structural view of the present utility model.

Detailed Description

The utility model is further described in connection with the following detailed description, in order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the utility model easy to understand.

Referring to fig. 3, the present embodiment adopts the following technical scheme: the ultrasonic transducer structure comprises a shell 1, a crystal oscillator piece 2, a crystal oscillator gland 3, a belleville spring 4, a gland nut 5, a lead 6, a sealing ring 7 and a transducer fixing head 8, wherein the crystal oscillator piece 2 is arranged in the shell 1, the crystal oscillator piece 2 is provided with the crystal oscillator gland 3, the belleville spring 4 and the gland nut 5 are sequentially arranged on the crystal oscillator gland 3, and a coupling agent is poured between the crystal oscillator piece 2 and the shell 1; the crystal oscillator piece 2 is connected with a wiring pole at the center of the transducer fixing head 8 through a lead 6, the wiring pole is connected with a cable joint 9, and a sealing ring 7 is arranged between the shell 1 and the transducer fixing head 8 and is connected with the same through threads.

It should be noted that the threaded connection between the housing 1 and the transducer fixing head 8 is further provided with a thread sealant.

In addition, the shell 1 is made of stainless steel 316L or PE, and the diameters of the transducers are 15mm, 20mm and 25mm respectively.

The thickness of the emitting surface of the transducer shell of the specific embodiment is designed to be matched with the wavelength of the crystal oscillator sheet, namely, the wavelength=sound velocity/frequency (lambda=c/ƒ), the frequency of the crystal oscillator sheet is 1000kHz, the sound velocity of water at 20 ℃ is 1414m/s, and the calculated wavelength is about 1.41mm. The thickness of the housing emission surface is designed to be twice the wavelength, i.e. the thickness of the housing emission surface is 2.82mm, taking into account the housing strength and rigidity.

And considering the expansion deformation condition when the temperature change gradient is large, the contact surface of the crystal oscillator piece and the shell adopts a high-temperature resistant couplant, and the crystal oscillator piece adopts a pair of butterfly-shaped spring compression structures.

In design, the two-pole outgoing lines of the transducer shell and the crystal oscillator sheet are structurally packaged by adopting an insulating gasket and an insulating sleeve at the joint of the transducer fixing head (and the transducer seat), so that the purpose of insulating and isolating the transducer and the meter body is realized.

In the specific embodiment, the transducer housing 1 is made of stainless steel 316L or PE, the diameters of the transducers are respectively (15 mm/20mm/25 mm), and the lengths of the transducers are set according to the protrusion degree of the transducers and the thickness of the pipeline wall. The crystal oscillator plate 2 is pressed in the transducer shell by the wafer gland 3 through the compression nut 5 by the disc spring 4, and a coupling agent is poured between the crystal oscillator plate and the shell. The shell is connected with the transducer fixing head 8 through internal and external threads, and sealing is realized by the shell section and the inner sealing surface of the transducer fixing head through pressing the sealing ring 7. The two-pole lead 6 of the crystal oscillator is welded with a wiring pole at the center of the transducer fixing head 8, and a wiring pole on the transducer fixing head is fixed with the transducer fixing head through an insulating sleeve. The two leads are insulated from the transducer housing and form a seal. The transducer and the transducer seat (meter body) are fixedly connected through screw threads, and the contact sealing surfaces of the transducer and the transducer seat are sleeved with a sealing gasket to compress and seal in advance, and the compressing force is implemented through a torque wrench. The cable lead plug is locked on the transducer seat cover by the sealing lock head, and is led out and sealed.

The method for packaging the ultrasonic transducer in the specific embodiment comprises the following steps:

Before packaging the transducers in this embodiment, machining deviations of the housing and internal packaging components are strictly detected, and after packaging, each transducer is tested and data is recorded according to an operation flow. The transducer package is then uniquely numbered for inspection.

The foregoing has shown and described the basic principles and main features of the present utility model and the advantages of the present utility model. It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made without departing from the spirit and scope of the utility model, which is defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims

1. The ultrasonic transducer structure is characterized by comprising a shell (1), a crystal oscillator piece (2), a wafer gland (3), a disc spring (4), a compression nut (5), a lead (6), a sealing ring (7) and a transducer fixing head (8), wherein the crystal oscillator piece (2) is arranged in the shell (1), the wafer gland (3) is arranged on the crystal oscillator piece (2), the disc spring (4) and the compression nut (5) are sequentially arranged on the wafer gland (3), and a coupling agent is filled between the crystal oscillator piece (2) and the shell (1); the crystal oscillator piece (2) is connected with a wiring pole at the center of the transducer fixing head (8) through a lead (6), the wiring pole is connected with a cable connector (9), and a sealing ring (7) is arranged between the shell (1) and the transducer fixing head (8) and is connected through threads.

2. An ultrasonic transducer structure according to claim 1, wherein the threaded connection between the housing (1) and the transducer fixing head (8) is further provided with a thread sealant.

3. An ultrasound transducer structure according to claim 1, wherein the housing (1) is a stainless steel 316L housing or a PE housing.

4. An ultrasound transducer structure according to claim 1, where the transducer diameters are 15mm, 20mm, 25mm, respectively.

5. An ultrasound transducer structure according to claim 1, where the emission angle of the housing (1) is less than or equal to 5 °, and the housing emission surface thickness is 2.82mm.