Dual-element ultrasonic transducer

Abstract

The invention relates to the field of non-destructive testing and can be used for the ultrasonic inspection of pipes, workpieces, sheet metal products and profiled metal products. The technical result is an improvement in the operating characteristics of a dual-element ultrasonic transducer, particularly in terms of reliability and serviceability. The present dual-element ultrasonic transducer includes a base with the following mounted in succession thereon: a housing of a transmitting unit, containing a prism of a transmitting piezoelectric element and, attached to said prism, at least one transmitting piezoelectric element; an insulating screen having one acoustic or electromagnetic screening layer, or several screening layers simultaneously, in various combinations and configurations; and a housing of a receiving unit, containing a prism of a receiving piezoelectric element and, attached thereto, at least one receiving piezoelectric element, wherein all of the elements are rigidly connected to one another with the aid of a locking member.

Description

Ultrasonic dual-cavity transducer

[0001] The invention relates to the field of non-destructive testing and can be used for ultrasonic testing of pipes, blanks, sheet and rolled products.

[0002] The state of the art includes separate-combined ultrasonic transducers used to construct systems for manual, automated and automatic ultrasonic testing of materials (see the publication of the book: Non-destructive testing. Book 2. Acoustic testing methods. Edited by V.V. Sukhorukov. Moscow: Higher School, 1991, pp. 102-106).

[0003] The typical design of a separate-combined ultrasonic transducer contains a housing and the following located in it:

[0004] a prism with at least one emitting piezoelectric element;

[0005] a prism with at least one receiving piezoelectric element;

[0006] at least one acoustic insulating screen (IS) that absorbs acoustic energy;

[0007] at least one electromagnetic screen (ES) that provides electromagnetic shielding between the emitting and receiving piezoelectric elements.

[0008] This design of a separate-combined ultrasonic transducer, in comparison with other types of ultrasonic transducers, allows to significantly reduce the uncontrolled zone near the surface of the object of control. This is achieved due to the fact that the emitting part of the transducer (a prism with one or more emitting piezoelectric elements glued to it) and the receiving part of the transducer (a prism with one or more receiving piezoelectric elements glued to it) are electrically (due to the use of EE) and acoustically (due to the use of IE) isolated from each other.

[0009] In order to obtain high defectoscopic properties of the converter, its prisms are usually made of a material with low hardness, for example, of organic glass. However, during the operation of the converter, the degree of acoustic insulation decreases, which leads to a gradual degradation of the useful properties of the converter, in particular, to a decrease in its sensitivity and an increase in the dead zone.

[0010] One of the main factors leading to the weakening of the insulating properties of the IE material is its gradual saturation with contact liquid (for example, water), which leads to a decrease in the attenuation of the energy of elastic waves in the IE, and, as a consequence, to an increase in the acoustic coupling between the emitting and receiving parts of the transducer.

[0011] Another factor leading to degradation of the transducer properties is the destruction of its working surface, which occurs due to mechanical and erosive wear of the prisms and the EE separating them. Moreover, this wear occurs, as a rule, unevenly. In this case, the most important, from the point of view of preserving the transducer properties, central part of its working surface is most susceptible to wear. This happens because the transducer body, as a rule, is harder compared to the prisms and EE. Therefore, the rate of its destruction is significantly lower than the rate of destruction of the prisms and EE. As a result of such uneven wear of the transducer working surface, its flaw detection properties deteriorate, which, as a consequence, leads to a decrease in the quality and reliability of ultrasonic testing as a whole.

[0012] Technical solutions are also known in which the converter prisms are equipped with protectors made of wear-resistant material, such as glass or ceramics.

[0013] For example, wear-resistant SENDAST converters manufactured by 3T LLC, equipped with a ceramic protector, are known (see the publication on the Internet at the link: https: / 3tsensor.com / p111-sendast).

[0014] Such converters have a higher resistance to wear, but, in some cases, they do not provide the necessary flaw detection characteristics. This is due to the fact that solid materials have a higher acoustic impedance and are poorly matched with the acoustic impedance of water or another liquid that provides acoustic contact of the converter with the test object. As a result, the sensitivity of the converter to the working gap increases, as well as to distortions of the spectrum of ultrasonic signals. The latter leads to reverberation noise, expansion of the dead zone of the converter and a decrease in its beam resolution. The instability of the characteristics of such converters, as a rule, does not allow them to be used in highly sensitive multichannel ultrasonic testing systems.

[0015] Thus, wear-resistant hard prisms have high acoustic impedance and are of little use in multichannel ultrasonic testing systems, while prisms made of soft material, which in principle have high flaw detection characteristics, quickly degrade.

[0016] At the same time, the repair of converters, including restoration of the shape of the working surface of the prisms, is very expensive and not effective enough. After several restorations, such converters, as a rule, completely lose their defectoscopy characteristics.

[0017] An ultrasonic separate-combined transducer described in the patent for invention of the Russian Federation No. 2718129, published on March 30, 2020, IPC H04R 17 / 00, was selected as a prototype of the claimed technical solution.

[0018] The well-known design of the ultrasonic split-combined transducer has good durability and reliability, while it provides high flaw detection properties.

[0019] The specified characteristics are achieved in that the ultrasonic separate-combined transducer comprises a housing, a radiating prism with a radiating piezoelectric element fixed thereto, a receiving prism with a receiving piezoelectric element fixed thereto, and an electroacoustic screen installed between the prisms, including at least one insulating layer, wherein the electroacoustic screen also additionally comprises a reflective screen installed parallel to the insulating layer immediately after it along the course of movement of ultrasonic waves, and which is intended to return acoustic energy back to the insulating layer and, further, to the radiating prism. As an embodiment of the invention, the reflective screen can also be installed between two insulating layers.

[0020] In this case, the reflective screen is made of a wear-resistant material, for example, a dielectric (ceramics, ferrites) or a metal with a hardness exceeding the hardness of the material of the prisms and / or insulating layer, and satisfying the condition: (RS) ОЭ > (RS) ИС , Where:

[0021] (RS) ОЭ - the product of the specific gravity of the reflective screen material and the velocity of the longitudinal elastic wave in this material;

[0022] (RS) ИС - the product of the specific gravity of the insulating layer material and the velocity of the longitudinal elastic wave in this material.

[0023] The nature of prism wear in the case of using such a system is due to the division of the prism wear surface into two parts, due to which the prism wear occurs separately in each of these two parts. However, since the electroacoustic screen includes a solid element - a reflective screen, it continues to maintain its insulating properties even with relatively strong wear of the prisms.

[0024] However, such a converter also loses its operational properties over time, which requires its complete replacement even if only one of its elements has been destroyed or lost its flaw detection properties. This is due to the fact that all three elements - the receiving and emitting prisms, as well as the electroacoustic screen - are glued into the housing, uniting them into a single non-separable structure.

[0025] The technical problem solved by the claimed technical solution is the insufficient reliability or low maintainability of known designs of ultrasonic separate-combined transducers, due to which they cannot be used, for example, in automatic multi-channel ultrasonic testing systems.

[0026] The technical result of the claimed invention is an increase in the operational characteristics, namely the reliability and maintainability of the ultrasonic dual-channel transducer, which can be used, in particular, in an automatic multi-channel ultrasonic testing system.

[0027] The specified technical result is achieved due to the design of an ultrasonic separate-combined transducer, which is a collapsible structure including a base on which the following are installed in series: a radiating unit housing in which a prism of a radiating piezoelectric element is placed with at least one radiating piezoelectric element fixed thereto; an insulating screen which contains at least one shielding layer - acoustic or electromagnetic, or several shielding layers simultaneously in their various combinations and combinations; a receiving unit housing in which a prism of a receiving piezoelectric element is placed with at least one receiving piezoelectric element fixed thereto, wherein all elements of the structure are rigidly connected to each other by means of a fixing element.

[0028] In addition, on the same base, elements of the working fluid supply system can also be installed, ensuring acoustic contact of the ultrasonic split-combined transducer with the surface of the test object.

[0029] Thus, the claimed collapsible design of the ultrasonic separate-combined transducer allows for easy replacement or repair of damaged parts and full restoration of the transducer's functionality without the need for its complete replacement.

[0030] For example, a common reason for replacing an ultrasonic dual-cavity transducer is damage to the insulating screen, which is usually a flat plate and is a relatively inexpensive part. In this case, a damaged insulating screen can be replaced with a working one, or its functionality can be easily restored by turning it by an angle of 90º or 180º, or by removing (cutting) its damaged part.

[0031] In case of damage to one of the prisms, its replacement is also a simple technological operation, and the cost of such a replacement will be half as much as the cost of replacing the entire converter.

[0032] The claimed design of the ultrasonic split-combined transducer is illustrated by the image in Fig. 1, which shows the following positions: Figure 1

[0033] (1) – object of control;

[0034] (2) – base;

[0035] (3) – body of the radiating unit;

[0036] (4) – prism of the emitting piezoelectric element;

[0037] (5) – emitting piezoelectric element;

[0038] (6) – insulating screen;

[0039] (7) – receiver unit housing;

[0040] (8) – prism of the receiving piezoelectric element;

[0041] (9) – receiving piezoelectric element;

[0042] (10) – fixing element;

[0043] (11) – parts of the contact liquid supply system.

[0044] Shown is an ultrasonic dual-cavity transducer installed on the test object (1).

[0045] In this case, the ultrasonic separate-combined transducer is a collapsible structure, including a base (2), on which the following are installed in series:

[0046] a housing of the emitting unit (3), in which a prism of the emitting piezoelectric element (4) is placed with at least one emitting piezoelectric element (5) fixed to it;

[0047] an insulating screen (6), which contains at least one screening layer – acoustic or electromagnetic, or several such layers at the same time in their various combinations and combinations;

[0048] a receiving unit housing (7) in which a receiving piezoelectric element prism (8) is placed with at least one receiving piezoelectric element (9) secured to it.

[0049] In this case, all elements of the structure are rigidly connected to each other using a fixing element (10), for example, using a screw.

[0050] In addition, elements of the contact liquid supply system (11) can also be installed on the base (2), ensuring acoustic contact of the ultrasonic dual-combined transducer with the surface of the test object (1).

[0051] The claimed design operates as follows. Before conducting research, the assembled ultrasonic separate-combined transducer is installed on the surface of the test object (1).

[0052] In this case, depending on the task at hand, the required gap between the working surface of the prisms (4) and (8) and the surface of the test object (1) is set in advance, and the insulating screen (6) is also ensured to fit against the surface of the test object (1).

[0053] In order to ensure acoustic contact, a contacting liquid is supplied to the working area using its supply system (11), and then ultrasonic examinations of the test object (1) are carried out in accordance with a specified program.

[0054] In the event of damage to the elements of the ultrasonic separate-combined transducer design during operation, for example, prisms (4), (8) or an insulating screen (6), the transducer is disassembled, for which the fixing element (10) is released, after which the damaged element is replaced and the design is reconnected also using the fixing element (10).

[0055] Laboratory tests of the claimed design have proven its operability and the possibility of application in automatic multi-channel ultrasonic testing systems used in metallurgical industry enterprises.

[0056] Thus, the implementation of an ultrasonic separate-combined transducer as a collapsible and disassemblable device, providing the possibility of replacing one or several main design elements at once: prisms or an insulating screen, increases its reliability and maintainability, and also leads to a reduction in costs associated with the maintenance of industrial equipment, for example, conveyor systems for automatic multi-channel ultrasonic testing used in quality control of such products as pipes, sheet metal or rolled products.

Claims

An ultrasonic dual-combined transducer, which is a collapsible structure that includes a base on which the following are mounted in series: a radiating unit housing in which a prism of a radiating piezoelectric element is placed with at least one radiating piezoelectric element secured thereto; an insulating screen that contains at least one shielding layer - acoustic or electromagnetic, or several shielding layers simultaneously in their various combinations and combinations; a receiving unit housing in which a prism of a receiving piezoelectric element is placed with at least one receiving piezoelectric element secured thereto, wherein all elements of the structure are connected to one another by means of a fixing element. An ultrasonic dual-component transducer according to paragraph 1, characterized in that elements of the working fluid supply system are installed on the base, ensuring acoustic contact of the ultrasonic dual-component transducer with the surface of the test object.

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