SU1567884A1 - Method of determining inside dimension of articles having a cavity - Google Patents

Abstract

This invention relates to a measurement technique. The aim of the invention is to improve the accuracy and sensitivity of measurements. The product is filled with gas and ultrasonic oscillations are excited in it, the radial resonant frequency of these oscillations in gas is measured, the value of which, taking into account the shape of the internal cavity of the product in the measured cross section and the velocity of propagation of ultrasonic oscillations in gas, is calculated by taking into account the internal diameter of the product. By damping the ultrasonic oscillations in the product, it is easier to determine the resonant frequencies of the gas oscillations, which increases the sensitivity of the measurements. 1 Cp., 1 Il.

Description

The invention relates to a measurement technique and can be used to measure the internal diameter of pipes, including thin-walled ones.

The aim of the invention is to improve the accuracy and sensitivity of measurements.

The drawing shows a device for implementing the proposed method for determining the internal size of a product with a cavity.

The device contains a radiating and receiving piezoelectric transducers 1 and 2, which are placed on the outer cylindrical surface of the controlled pipe 3 and mounted in a damping ring 4, a generator 5, to the output of which a transducer 1 is connected, an indicator unit 6, to the input of which is connected a piezotransducer 2, frequency 7, also connected to the outlet of the generator 5. A cylinder 8 is used to fill the pipe with gas, and the adjustment and pressure change are performed by a valve 9 and a pressure gauge 10. The pipe 3 is sealed with plugs 11.

The method is carried out as follows.

The product is filled with a gas of a fixed composition at given temperatures and pressures. Ultrasonic oscillations are excited in the product in the transverse direction, the radial resonant frequency of these oscillations in the gas is measured, according to the value of which, taking into account the shape of the internal cavity of the product and the known speed of propagation of ultrasonic oscillations in gas,

a j

00

oo

4i

the diameter d of the product in the passage by the formula

 with,

where c is the speed of sound in gas;

Ob are the roots of the characteristic equation (W) 0, where 1 (x) is the Bessel function.

Thus, due to the direct determination of the resonant frequency of ultrasonic vibrations in the gas of the internal diameter of the product, the accuracy is increased.

The damping of the ultrasonic oscillations of the product itself simplifies finding the radial resonant frequency of ultrasonic oscillations in a gas and increases the sensitivity of measurements.

The application of the proposed method will simplify the control of the values of the internal diameter of pipes, especially thin-walled ones, and, consequently, increase its efficiency,

Claims (1)

Invention Formula 1, a method for determining the internal size of a product with a cavity, which is in excitation in the product of ultrasonic vibrations, in measuring the resonant frequency of these oscillations and determining, taking into account the last desired parameter, characterized in that, in order to improve the accuracy, the product is filled with gas, measure the radial resonant frequency of the ultrasonic oscillations of the gas in the product, the size of which determines its internal diameter. 2, the method according to claim 1, wherein, in order to increase the sensitivity, the product is damped. Editor oh, arrogant Compiled by V.Sorokin Tehred M. KhodanychKorrektor N King Order 1315 Circulation 478 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 Subscription