SU1305592A1 - Piezoelectric transducer for reception of acoustical emission signals - Google Patents

Abstract

The invention relates to a measurement technique and can be used in non-destructive testing devices of various designs. The aim of the invention is to increase the sensitivity by increasing the energy transfer rate. The sound transmitting waveguide 2, pressed without step transitions across the cross section of the waveguide 2 into the housing 1, is filled with an exponential one. The piezoceramic piezoelectric element 3, placed in the centering sleeve 4, isolated from the housing 1 by the soundproofing sleeve 5 and the washer 6, makes acoustic contact with the internal end of the exponential waveguide 2 by means of the sound transmitting fluid 7 placed in the calibrated washer 8 placed in the sleeve 4 between the ends of the waveguide 2 and the piezoelectric element 3, and provides the optimal transfer of energy from the waveguide 2 to the piezoelectric element 3, 1 sludge. with (L with e ate

Description

The invention relates to a measurement technique and can be used in non-destructive testing devices of various designs, in particular, when testing by the method of acoustic: emission (AE).

The purpose of the invention is to increase the sensitivity by increasing the energy transfer rate.

The drawing shows a piezoelectric transducer for receiving AE signals.

The converter for receiving acoustic emission signals includes a housing 1 in which one end of an exponential waveguide 2 is pressed. The piezoceramic element 3, which is located in the housing 1, is installed in the centering sleeve 4, which is isolated from the housing 1 by soundproofing sleeve 5 and a washer 6. Acoustic contact with an internal end zks- ponandogo. Waveguide 2 and piezoceramic element 3 are formed by a calibrated volume of contact liquid 7, determined by the thickness of a calibrated washer 8 placed in the sleeve 4 between piezoelectric element 3 and the end of the waveguide 2. Position 9 denotes a fastening nut and 10 is a controlled item.

The converter works as follows.

The converter is mounted on the product 10 and the wide end of the waveguide 2 is rigidly attached to the product 10. The acoustic emission signals arising in the product 10 are transmitted through the waveguide 2 through the contact fluid 7 to the piezoelectric element 3, converted into electrical signals and fed to a recorder (not shown).

The use of an exponential waveguide 2, performed without abrupt transitions across the cross section, makes it possible to avoid energy losses due to reflections from transitions with different wave impedances.

The calibrated microvolume of the sound-transmitting contact liquid 7 provides the optimal signal energy transfer from the internal end of the VolNIIPI Order 1423/42 Circulation 777 Subscription Polyvol. pr-tie, Uzhgorod, st. Project, 4

Novod 2 to the end of the piezoceramic element 3, excluding the appearance of standing waves in the liquid 7. The presence of soundproofing sleeves 4 and washers 6 ensures acoustic pickup of the piezoceramic element 3 from the housing, and pressing the exponential waveguide 2 without cross-sections through the housing 1, made of materials with different sound propagation velocities, eliminates the occurrence of standing waves in waveguide 2, the transfer of signal energy from waveguide 2 to housing 1, and consequently, energy loss. In addition, the use of the microvolume of the sound-transmitting contact liquid 7 prevents it from flowing out between the ends of the waveguide 2 and the piezoelectric element 3, and therefore eliminates the requirement for sealing the housing I, ensuring high reliability of the converter,

Invention Formula

A piezoelectric transducer for receiving acoustic emission signals comprising a hollow body, a piezoelectric element mounted inside the body, and an old acoustic conductor fixed at one end in the body coaxially with the piezoelectric element and connected to it by means of contact fluid, from. Due to the fact that, in order to increase sensitivity by increasing the energy transfer coefficient, it is equipped with a sound insulating sleeve installed inside the sleeve with a centering sleeve, a soundproofing tab located at the end of the centering sleeve and a calibrated plug mounted on the end of the sound-insulated sleeve. water, the piezoelectric element is installed in the centering sleeve, the contact liquid is placed inside the calibrated solder and the sound pipe is made in the form of an exponential waveguide, tapering to fixed This end is made of a material whose propagation velocity of acoustic oscillations differs from the propagation velocity of oscillations in the material of the housing.

Claims (1)

A piezoelectric transducer for receiving acoustic emission signals comprising a hollow body, a piezoelectric element mounted inside the body, and a rod sound conductor fixed at one end in the body coaxially to the piezoelectric element and connected thereto by means of contact liquid, revealing that, in order to increase sensitivity by increasing energy transfer coefficient, it is equipped with a soundproof sleeve installed inside the sleeve with a centering sleeve, a soundproof washer located at the centering end the sleeve, and a calibrated washer mounted on the end of the sound duct fixed in the housing, the piezoelectric element is installed in the centering sleeve, the contact fluid is placed inside the calibrated washer, and the sound duct is made in the form of an exponential waveguide, tapering to the fixed end, made of a material whose acoustic velocity differs in from the speed of propagation of vibrations in the body material