SU1183887A1 - Contactless impedance method of inspecting quality of article coating - Google Patents

Description

The invention relates to non-destructive testing and can be used for ultrasonic monitoring of the quality of the coating and cladding of multi-purpose structures - pressure slopes of hydraulic structures, canals, water lines, road and airfield pavements.

The purpose of the invention is to improve the accuracy of control.

The drawing shows a device for implementing a contactless impedance method of monitoring the quality of the coating products.

The device contains a radiator

1 ultrasonic vibrations and receivers 2 and 3, which are connected, respectively, with amplifiers 4

and 5. The outputs of these amplifiers are connected. phase meter 6 and a log meter 7, the signal from which is fed to the microprocessor 8. The signal to the emitter 1 is supplied from the generator 9 harmonic oscillations, the frequency of which is recorded by the frequency meter 10.

The proposed control method is as follows.

The emitter 1 ultrasonic vibrations and receivers 2 and 3 are located near the surface of the test product on the same normal to this surface. And the receivers

2 and 3 are set at a distance of s! significantly shorter wavelength. On the controlled surface of the radiator 1, which receives a signal from the generator 9, an acoustic wave is sent. Receivers

2 and 3 measure the amplitude of the ultrasonic wave reflected from the surface of the test item. Then the signals from receivers 2 and 3 are amplified by identical broadband amplifiers 4 and 5. With the help of the fa-? Zometer 6 is determined by the phase difference

ten

άφ =, - Ψ ₂ Ultrasonic waves at the measurement points, and with the help of a logometer 7, the ratio davR, '

. Lenia = at measurement points. In ⁹ · <2.

In the case when receivers 2 and 3 measuring sound pressure are at a distance & c) significantly shorter than the wavelength, then the surface impedance is calculated from the readings of the logometer 7 () and

phase meter 6 () according to the following expression

15

? " ^e " Ryg

• 4б * + (<* Л-А); ^&

where'ώ is the cyclic frequency of oscillations;

20 p - the density of the medium in which

elastic waves propagate.

The signals from the logometer 7, phase meter 6 and frequency meter 10 are received

²⁵ to microprocessor 8, which calculates the dependences and compares them with the impedance portraits in its memory that correspond to one or another typical values

30 controlled coating parameters (porosity _L density, thickness, etc.) obtained in advance under reference conditions. To measure the surface impedance of a controlled

35 products at each point move the receiving-emitting device, including the radiator 1, receivers 2 and 3, along the surface of the product at a given speed.

40 Contactless impedance quality control method for coatings of products allows to increase the accuracy of control, since a direct measurement of bolt-critical coating impedance is carried out.

Claims (1)

CONTACTLESS IMPEDANCE <COATING QUALITY CONTROL METHOD ^ OF PRODUCTS, consisting in that the controlled product is placed in the ultrasound field, measure at a given point, the amplitude of the ultrasonic wave reflected from the test item, characterized in that, in order to improve the control accuracy, the amplitude of the ultrasound wave is measured at a second point located with the first dot at one normal to the surface of the test item and spaced from it at a distance less than wavelengths, fix the phase difference of the ultrasonic wave at these points and determine the impedance of the product by the ratio of the measured amplitudes and phase differences, the value of which determines the quality of the coating of the product. nineteen ω with 00 with 00 00 m > 1183887