SU1228009A1 - Acoustic receiving converter - Google Patents

Abstract

The invention relates to a measurement technique and can be used for research and analysis. The invention relates to a measurement technology and can be used for research and analysis of materials and products with sound and ultrasonic vibrations. The purpose of the invention is to reduce the level of spurious signals and increase sensitivity. The drawing shows an acoustic 1 fienns: transducer, cut. The acoustic receiving transducer consists of a hollow cylindrical body 1 placed in it an acoustic waveguide 2 and a damper 3, between which a piezoelectric element 4 is fixed. From the end surface of the waveguide 2, the ball 5 is fixed in the case 1 to rotate. The end surface of the waveguide 2, adjacent to the ball, is filled with a spherical concave curvature with radius and products using sound and ultrasonic vibrations. The aim of the invention is to reduce the level of spurious signals and increase sensitivity. The acoustic receiver transducer is equipped with a ball rolled into the end of the hollow cylindrical body. The free end surface of the waveguide is spherically concave with a radius of curvature equal to the ball radius; the internal cavity of the body is filled with an electrically nonconducting fluid. 1 il. equal to the radius of the sound-conducting ball 5. The sensor body 1 is filled with an electrically conductive liquid 6, above which a movable stopper 7 is formed. The electrical signals are removed from the piezoelectric element 4 via an electrically conductive damper 3 using 1 coaxial connector 8. Shaft 5 has acoustic contact with the first solid body 9. When acoustic solidification of a solid body 9 is achieved, the acoustic receiving transducer is moved along its surface. At the same time, the ball 5 freely mounted in the housing 1 rolls along the surface of the solid body 9 under study. Acoustic waves from the solid body 9 passing through the ball 5 and the receiving waveguide 2 are converted by the piezoelectric element 4 into electrical signals picked up by means of a coaxial connector 8. Electroi ( World 00 o o o

Description

Aqueous fluid 6 fills the gap between the ball, 5 and the spherical end surface of the receiving waveguide 2, thereby providing acoustic contact between them, Pr and rotating the ball 5 also wets the surface of the probed solid 9. This increases the reliability of the acoustic contact in the zone contact of the acoustic transducer with the surface of the test solid 9, To prevent fluid 6 from escaping from the housing, its dynamic viscosity is selected within (0.9-1.7) N. s / m at a temperature of 293 K, and above it is formed cork 7. The boundaries of the viscosity of the beating fluid were established experimentally, as it was used castor oil. The temperature and, thus, the viscosity of the oil, it was found that the minimum value of the viscosity at which the fluid is still held in the housing is equal to 0.9 N, s / m2. Maximum in viscosity at which the liquid does not pass through the gap, formed by ball 5 and body 1, is 1.7 N. s / m. Due to the fact that the ball 5 contacts the surface of the test solid 9 in a small area (with ideally equal and strong surface - one point), a high resolution is achieved, equal to the diameter of the contact zone, since the mechanical surface damping is minimal. This ensures high sensitivity of the acoustic transducer when physicomechanical

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properties of materials, as well as ultrasonic flaw detection.

Cork 7 prevents the formation of air gaps in the volume of liquid 6 ;. If the viscosity is large enough, and the inner diameter of case 1 is small enough, the need for it may disappear.

During operation, the liquid 6 drops, and the plug 7 moves along with it. When the amount of liquid 6 decreases below the permissible level, its quantity can be re-located. When rolling ball 5,

contacting with liquids 6, provides lubrication of the point of contact with the solid body 9, which increases the reliability of the acoustic contact between them.

Claims (1)

Invention Formula An acoustic receiving transducer containing a cylindrical hollow body, a damper, a piezoelectric element and a waveguide waveguide installed in the acoustic contact, is rotatably mounted in the narrowed part of the body, while the space between the ball and the body is filled with contact liquid, so that that, in order to reduce the level of false signals and sensitivity, a cylindrical waveguide was inserted between the waveguide ball and the piezoelectric element, whose surface, facing the ball, was concave with the radius of curvature of the ball. 7777/7 /. / vx / Editor Oh, Fipitova Compiled by, Voronena Tehred.L.Serdyukov Proofreader V, Cabs Order 8255 Circulation 788 y Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Designer Works Patent, Uzhgorod, st. Gagarin, 101