Device for accurate measurement of the dimensions of an object by ultrasonic waves
First Claim
1. A device for the accurate measurement of dimensions of an object by ultrasonic waves, wherein said device comprises at least one ultransonic probe which operates as a transmitter-receiver for ultrasonic pulses, at least two reflecting barriers for said ultrasonic pulses, said barriers being in precisely fixed locations on the path of the ultransonic pulses so as to provide only partial obstruction of said path, means for placing, in a less obstructed portion of said path, an object whose dimensions are to be measured in the direction of propagation of the ultrasonic pulses, means for producing electric signals proportional in value to the time intervals between the reception on each probe of the various echoes corresponding to the reflections of the ultrasonic pulses from said barriers and from said object, and electronic processing means for comparing electric signals proportional to the interval between echoes corresponding to reflections from two of said barriers with electric signals proportional to the interval between echoes corresponding to reflection from different surfaces of said object and for thereby producing electric signals proportional to dimensions of said object.
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Accused Products
Abstract
In a device for accurately measuring the dimensions of metallic tubes and the like by supersonic waves in a liquid medium, typically water, obstructions providing reflecting boundaries that are partially reflecting and partially transparent for acoustic waves are provided at different distances from the transmitter-receiver between the latter and the object being measured and echoes of transmitted pulses from the reflecting boundaries of the obstructions and from those of the object being measured are processed in order to obtain the measured dimensions in a manner unaffected by changes in the velocity of propagation of the waves in the liquid medium because of temperature effects and the like. The pulse processing involves obtaining electrical signals proportional to the time delay between pairs of pulses and then comparing the time delays relating to precisely known distances with time delays relating to distances being measured. When the tube being measured is empty or otherwise filled with a poor medium for acoustic transmission, transmitter-receivers are provided on opposite sides of the tube and for checking fully the uniformity of tube thickness and diameters. A pair of cylindrical shells of diameter greater than the tube extending part way only into the path of the ultrasonic waves most conveniently provides the obstructions of precisely known dimensions.
88 Citations
10 Claims
- 1. A device for the accurate measurement of dimensions of an object by ultrasonic waves, wherein said device comprises at least one ultransonic probe which operates as a transmitter-receiver for ultrasonic pulses, at least two reflecting barriers for said ultrasonic pulses, said barriers being in precisely fixed locations on the path of the ultransonic pulses so as to provide only partial obstruction of said path, means for placing, in a less obstructed portion of said path, an object whose dimensions are to be measured in the direction of propagation of the ultrasonic pulses, means for producing electric signals proportional in value to the time intervals between the reception on each probe of the various echoes corresponding to the reflections of the ultrasonic pulses from said barriers and from said object, and electronic processing means for comparing electric signals proportional to the interval between echoes corresponding to reflections from two of said barriers with electric signals proportional to the interval between echoes corresponding to reflection from different surfaces of said object and for thereby producing electric signals proportional to dimensions of said object.
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6. A device according to claim 22, wherein the two reflecting barriers are respectively constituted by:
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a first cylindrical tube of external radius R2 which is coaxial with the tube being measured, with R2 >
R1, the external surface of radius R2 of said first barrier being located on a portion of the emission ultrasonic field of each probe; anda second cylindrical tube of radius R3, with R3 >
R2, the external surface of radius R3 of said second tube being located on a portion of the emission ultrasonic field of each probe.
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Specification