RU138092U1 - ULTRASONIC IMMERSION MULTI-SECTION PIEZOELECTRIC CONVERTER - Google Patents

Abstract

1. An ultrasonic immersion multielement piezoelectric transducer comprising a sealed housing with a damping substance, piezoelectric elements mounted inside the body and located symmetrically in the housing relative to the acoustic axis of the transducer, and a lens located on the side of the radiating surface of the piezoelectric elements, the polarization vector of all piezoelectric elements is directed either to the radiation direction, or in the direction of the damping substance, and the lens is made common to all piezoelectric elements or consists of separate projection, interconnected at the interface with a binder, such as glue or a polymer compound, characterized in that the piezoelectric elements are arranged to form a concave or convex surface relative to the lens, the gaps between the piezoelectric elements are filled with a polymer compound to form smoothly curved surfaces common with the piezoelectric elements, one of which faces the lens, and the other toward the damping substance, all the piezoelectric elements are made with a common positive and negative electrodes overlapping the gaps between the piezoelectric elements filled with the polymer compound and connected to the electrical sealed connector, the lens and the damping substance with the surfaces facing the surfaces formed by the piezoelectric elements and the polymer compound, each, for its part, is closely adjacent to the electrodes located on these surfaces, and the adjacent lens surfaces and damping substance repeat the surface of the electrodes to which they are adjacent, and the linear size of the radiating surface of each

Description

The utility model relates to ultrasonic measuring equipment, namely to piezoelectric transducers and can be used for flaw detection and thickness measurement in the study of various kinds of materials, in particular pipes, rolled metal, plastics and heterogeneous materials, such as, for example, welded structures.

Known ultrasonic transducer containing a housing with a protector in the form of a truncated cone, a piezoelectric element and a damper placed in the housing (see application GB No. 2091520, CL G01N 29/00, 07/28/1982).

This transducer creates only a longitudinal wave in the material under study and can be used only in the high-frequency region, which narrows the scope of its use. In addition, wetting fluid is required to install the transducer on the test article.

A separately-combined converter is known, in the case of which a transverse wave emitter and a receiving element are installed at an angle of 45 degrees (see FR patent No. 2499248, class G01N 29/00, 08/06/1982)

This transducer operates in the high-frequency region and requires considerable effort to ensure good acoustic contact, which narrows the scope of its use.

In addition, a common disadvantage of the above converters is that they cannot work in immersion mode.

The closest to the utility model in terms of technical nature and the achieved result is an ultrasonic immersion multielement piezoelectric transducer comprising a sealed housing with damping substance, piezoelectric elements mounted inside the body and located symmetrically relative to the acoustic axis of the transducer in the case, and a lens conjugated with the piezoelectric elements from the side of the radiating surface piezoelectric elements, the acoustic axis of the piezoelectric elements intersect each other on the longitudinal axis of the conversion to the transducer radiation direction, the polarization vector of all piezoelectric elements is directed either towards the radiation or towards the damping substance, and the lens is made common to all piezoelectric elements or consists of separate sections interconnected at the interface with a binder, for example, glue or a polymer compound ( see utility model patent RU No. 114,786, class G01N 29/00, 04/10/2012).

This converter is made with the possibility of its use for monitoring objects with a rough, unprepared and curved surface. However, this converter has a relatively complex design, which reduces its reliability and limits the range of possible configurations of the radiation pattern.

The task to which the utility model is directed is to increase the reliability of the integrity control of the controlled material by increasing the length of the working zone and expanding the radiation pattern of the piezoelectric transducer while simplifying the design of the transducer.

The technical result consists in the fact that an increase in the reliability of the integrity control of the controlled material is achieved.

The problem is solved, and the technical result is achieved due to the fact that the ultrasonic immersion multi-element piezoelectric transducer contains a sealed housing with a damping substance, piezoelectric elements installed inside the body and located in the body symmetrically relative to the acoustic axis of the transducer, and a lens located on the side of the radiating surface of the piezoelectric elements, acoustic the axes of the piezoelectric elements intersect each other on the longitudinal axis of the transducer, the polarization vector of all the piezoelectric elements It is directed either toward the radiation or towards the damping substance, the lens being common for all piezoelectric elements or consisting of separate sections interconnected at the interface with a binder, for example, with adhesive or a polymer compound, the piezoelectric elements are arranged to form concave or convex relative to the lens surfaces, the gaps between the piezoelectric elements are filled with a polymer compound with the formation of smoothly curved surfaces common with the piezoelectric elements, one of which is facing well, the lenses, and the other towards the damping substance, all the piezoelectric elements are made with a common positive and negative electrodes, overlapping the gaps filled with the polymer compound between the piezoelectric elements and connected to the electrical sealed connector, while the lens and the damping substance are the surfaces facing the formed piezoelectric elements and the polymer compound surfaces, each for its part, is tightly adjacent to the electrodes located on these surfaces, and the adjacent surfaces inces and damping substance repeat the surfaces of the electrodes to which they are adjacent, and the linear size of the radiating surface of each piezoelectric element is equal to or less than h = C / 2F, where C is the speed of sound in the material of the piezoelectric element; F is the resonant frequency of the piezoelectric element.

The piezoelectric elements preferably have the same shape with respect to the longitudinal axis of the transducer,

Piezoelectric elements with the side facing the controlled material can be located at an acute or obtuse angle to the acoustic axis of the piezoelectric transducer, respectively, in the case of the location of the piezoelectric elements with the formation of a concave or convex surface.

The lens, preferably made in the form of a layer of acoustically conductive solid material, has a thickness S opposite to each of the piezoelectric elements equal to

, где

where

λ is the ultrasound wavelength in the lens material;

c is the speed of sound in the lens material;

f is the working frequency of the piezoelectric element.

.The lens may have a wedge-shaped shape opposite each piezoelectric element in the plane of the longitudinal section passing through the acoustic axes of the piezoelectric elements, and the thickness of the lens at the point where the acoustic axis of the piezoelectric element passes through it is

.

The lens can be made with the cylindrical outer surface facing the concave part in the direction of the controlled material and made opposite each of the piezoelectric elements, moreover, the generatrix of the cylindrical surface is perpendicular to the plane in which the acoustic axis of the piezoelectric elements lie, the lens has the smallest thickness equal to λ / 4, and the generatrix of the cylindrical surface at the point of smallest thickness of the cylindrical surface intersects with the acoustic axis of the corresponding piezoelectric element with an increase in the thickness of the lens in n the board of this acoustic axis.

The implementation of the piezoelectric elements arranged with the formation of a concave or convex surface relative to the lens with gaps between the piezoelectric elements filled with a polymer compound with the formation of smoothly curved surfaces common with the piezoelectric elements, one of which faces the lens and the other towards the damping substance in combination with the fact that all the piezoelectric elements made with a common positive and negative electrodes, overlapping the gaps filled with the polymer compound between the piezoelectric elements and sub closed to the electrical tight connector, while the lens and the damping substance surfaces facing the surfaces formed by the piezoelectric elements and the polymer compound, each for its part is tightly adjacent to the electrodes located on these surfaces, and the adjacent surfaces of the lens and damping substance repeat the surfaces of the electrodes to which they are adjacent, and the linear size of the radiating surface of each piezoelectric element is equal to or less than h = C / 2F, where C is the speed of sound in the material of the piezoelectric element; F - the resonant frequency of the piezoelectric element allows to simplify the design of the transducer due to the possibility of piezoelectric elements arranged with the electrodes in the form of a separate unit, which is easy to insert into the transducer during assembly or easily replaced if necessary, for example, during repair. Thus, the transducer can consist of separate structurally simple elements: a block of piezoelectric elements, a lens and a damping substance, from which the transducer of almost any necessary configuration is easily assembled. In addition, it is possible to create blocks of piezoelectric elements with a surface facing the lens, which can be two-dimensional, for example close to cylindrical, or three-dimensional, for example close to spherical, which in turn allows you to create transducers with almost any desired length of the working zone of the piezoelectric transducer, which allows to increase the reliability of the integrity control of the controlled material

позволяет добиться максимальной чувствительности пьезоэлектрического преобразователя за счет эффекта просветления.Making the lens thickness equal

allows you to achieve maximum sensitivity of the piezoelectric transducer due to the effect of enlightenment.

The implementation of the lens with the above wedge-shaped surfaces can reduce the duration of the echo pulse and increase the signal-to-noise ratio.

The implementation of the lens with cylindrical surfaces allows, in addition to the above qualities, to ensure the concentration of energy of the acoustic field in a given area.

In FIG. 1 is a longitudinal section through an ultrasonic immersion multi-element piezoelectric transducer with two piezoelectric elements and a lens with cylindrical surfaces.

In FIG. 2 is a longitudinal section through an ultrasonic immersion multi-element piezoelectric transducer with piezoelectric elements and a wedge-shaped lens opposite each piezoelectric element.

In FIG. 3 is a longitudinal section through an ultrasonic immersion multielement piezoelectric transducer with a convex surface formed by the piezoelectric elements facing the controlled material.

An ultrasonic immersion multielement piezoelectric transducer comprises a sealed housing 1 with a damping substance 2, piezoelectric elements 3 installed inside the housing 1 and located in the housing 1 symmetrically with respect to the acoustic axis 4 of the transducer, and a lens 5 located on the side of the radiating surface of the piezoelectric elements Piezoelectric elements 3 can be made in the form round, segment or rectangular plates and are located on the side facing the controlled material at a sharp α or obtuse β angle to the acoustics the axis 4 of the piezoelectric transducer, respectively, in the case of the arrangement of the piezoelectric elements 3 with the formation of a concave or convex surface, while the piezoelectric elements 3 preferably have a relatively uniform shape relative to the longitudinal axis (coinciding with the acoustic axis 4) of the transducer and are made with electrodes 6 and 7 on their opposite surfaces connected to an electrical sealed connector 8. The acoustic axis 9 of the piezoelectric elements 3 intersect each other on the longitudinal axis of the transducer.

The polarization vector of all piezoelectric elements 3 is directed either to the side of radiation or to the side of the damping substance 2, moreover, the lens 5 is made common to all piezoelectric elements 3 or consists of separate sections 10 connected to each other at the interface with a binder, for example, with glue or a polymer compound.

The piezoelectric elements 3 are arranged with the formation of a concave (Fig. 1 and 2) or convex (Fig. 3) relative to the lens 5 of the surface. The spaces between the piezoelectric elements 3 are filled with a polymer compound 11 with the formation of smoothly curved surfaces common with the piezoelectric elements 3, one of which faces the lens 5 and the other towards the damping substance 2.

All piezoelectric elements 3 are made with a common positive 7 and negative 6 electrodes, overlapping the gaps filled with the polymer compound 11 between the piezoelectric elements 3 and connected to the electrical sealed connector 8, while the lens 5 and the damping substance 2 surfaces facing the formed piezoelectric elements 3 and the polymer compound 11 surfaces, each for its part, is closely adjacent to the electrodes 6 and 7 located on these surfaces, and the adjacent surfaces of the lens 5 and damping substance 2 are oryayut surface electrodes 6 and 7 to which they are adjacent, and the linear dimension of the radiating surface of each piezoelectric element 3 is equal to or less than h = C / 2F, where C - sound speed in material of piezoelectric element 3; F is the resonant frequency of the piezoelectric element 3.

Lens 5, preferably made in the form of a layer of acoustically conductive solid material, has a thickness S opposite each of the piezoelectric elements (not shown), equal

, где

where

λ is the ultrasound wavelength in the lens material;

C is the speed of sound in the lens material;

f is the working frequency of the piezoelectric element.

.The lens 5 may have a wedge-shaped shape opposite each piezoelectric element 3 in the longitudinal section plane passing through the acoustic axes 9 of the piezoelectric elements, and the thickness of the lens at the point where the acoustic axis 9 of the piezoelectric element passes through it is

.

Lens 5 can be made with the cylindrical outer surface facing the concave part toward the material to be controlled and made opposite each of the piezoelectric elements 3 (Fig. 1), moreover, the generatrix of the cylindrical surface is perpendicular to the plane in which the acoustic axes 9 of the piezoelectric elements lie, lens 5 has the smallest thickness, equal to λ / 4, and the generatrix of the cylindrical surface at the point of smallest thickness of the cylindrical surface intersects with the acoustic axis 9 of the corresponding piezoelectric element with increasing thickness lenses away from this acoustic axis 9.

Ultrasonic immersion multi-element piezoelectric transducer operates as follows.

After the transducer is installed in the liquid with a lens 5 above the surface of the controlled material, exciting voltage is applied to the terminals of the electrical tight connector 8 or, in the case of receiving ultrasonic vibrations, the received signal is removed from these conclusions. In the radiation mode, due to the connection of the electrodes of the piezoelectric elements 3 to the corresponding output of the connector 8, the piezoelectric elements 3 oscillate in phase, emitting longitudinal waves into the liquid. The wave front reaches the surface of the controlled object and, depending on the angle of incidence, forms the front of longitudinal or transverse waves in it. When this front meets a material inhomogeneity or defect, a reflected echo pulse is formed.

In the receiving mode, the reflected waves are received by all of the piezoelectric elements 3 or part thereof and form an output electrical signal at the terminals of the connector 8.

Placing the piezoelectric elements 3 in the manner described above in combination with performing them in pairs with the same shape allows you to increase the length of the working zone of the piezoelectric transducer and expand its radiation pattern, which ultimately allows to increase the reliability of the integrity control of the controlled material.

The immersion type of contact of the converter with the controlled object makes it possible to control materials with a rough surface (for example, castings) and long products, as well as to increase the life of the converter.

The ability to concentrate the energy of the acoustic field in a predetermined working area provides increased control reliability in bulk products.

The expansion of the radiation pattern provides the ability to detect randomly oriented defects.

This utility model can be used for flaw detection and thickness measurement of structural material in mechanical engineering, pipeline and railway transport.

Claims (6)

1. An ultrasonic immersion multielement piezoelectric transducer comprising a sealed housing with a damping substance, piezoelectric elements mounted inside the body and located symmetrically in the housing relative to the acoustic axis of the transducer, and a lens located on the side of the radiating surface of the piezoelectric elements, the polarization vector of all piezoelectric elements is directed either to the radiation direction, or in the direction of the damping substance, and the lens is made common to all piezoelectric elements or consists of separate projection, interconnected at the interface with a binder, such as glue or a polymer compound, characterized in that the piezoelectric elements are arranged to form a concave or convex surface relative to the lens, the gaps between the piezoelectric elements are filled with a polymer compound to form smoothly curved surfaces common with the piezoelectric elements, one of which faces the lens, and the other toward the damping substance, all the piezoelectric elements are made with a common positive and negative electrodes overlapping the gaps between the piezoelectric elements filled with the polymer compound and connected to the electrical sealed connector, the lens and the damping substance with the surfaces facing the surfaces formed by the piezoelectric elements and the polymer compound, each, for its part, is tightly adjacent to the electrodes located on these surfaces, and the adjacent lens surfaces and damping substance repeat the surface of the electrodes to which they are adjacent, and the linear size of the radiating surface of each piezoelectric element is equal to or less than h = C / 2F, where C is the speed of sound in the material of the piezoelectric element; F is the resonant frequency of the piezoelectric element. 2. The transducer according to claim 1, characterized in that the piezoelectric elements have a pairwise identical shape relative to the longitudinal axis of the transducer. 3. The transducer according to claim 1, characterized in that the piezoelectric elements with the side facing the controlled material are located at an acute or obtuse angle to the acoustic axis of the piezoelectric transducer, respectively, in the case of the arrangement of the piezoelectric elements with the formation of a concave or convex surface. 4. The transducer according to claim 1, characterized in that the lens, made in the form of a layer of acoustically conductive solid material, has a thickness S opposite to each of the piezoelectric elements equal to $$\frac{\lambda }{\mathrm{four}}=\frac{c}{\mathrm{four}f},$$

where λ is the ultrasound wavelength in the lens material; C is the speed of sound in the lens material; f is the working frequency of the piezoelectric element. 5. The Converter according to claim 1, characterized in that the lens has a wedge-shaped shape in the plane of the longitudinal section passing through the acoustic axis of the piezoelectric elements, and the thickness of the lens at the point where the acoustic axis of the piezoelectric element passes through it is $$\frac{\lambda }{\mathrm{four}}.$$

6. The transducer according to claim 1, characterized in that the lens is made with a cylindrical outer surface facing the concave part towards the material being controlled and made opposite each of the piezoelectric elements, the generatrix of the cylindrical surface being perpendicular to the plane in which the acoustic axes of the piezoelectric elements lie, the lens has the smallest a thickness equal to λ / 4, and the generatrix of the cylindrical surface at the point of smallest thickness of the lens with the cylindrical surface intersects with the acoustic axis of the corresponding element with an increase in the thickness of the lens in the direction from this acoustic axis.

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