Ultrasonic apparatus and method for measuring wall thickness
US4305294A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1980 |
| Grant date | Dec 15, 1981 |
| Priority date | — |
| Expiry date | Jan 10, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/02854
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is a method for determining the thickness of an object, including the steps of generating a higher order mode ultrasonic wave at a first location on the object, varying the frequency of the generated wave, and measuring, at a second location on the object, the minimum frequency at which the generated wave will propagate in the object. Where the ultrasonic wave generated is a horizontally polarized shear wave, the thickness t may be calculated from the relationship EQU t=(n V.sub.s)/(2 f.sub.c), where: PA1 n is the wave mode number, PA1 V.sub.s is the shear wave velocity, and PA1 f.sub.c is the minimum propagation frequency. Alternatively, the steps may be repeated for the next consecutive frequency minimum and the thickness t calculated from the formula EQU t=V.sub.s /(2 .DELTA.f.sub.c) where: .DELTA.f.sub.c is the difference between two consecutive frequency minima. An apparatus for performing the method includes a transmitting transducer for generating a higher order mode ultrasonic wave at a first location on the object, a signal generator for driving the transmitting transducer with a variable frequency, a receiving transducer for detecting the wave in the object, an …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.