Device for accurate measurement of the dimensions of an object by ultrasonic waves

Claim 3

A device according to claim 1, wherein said device comprises two ultrasonic probes (Ea and Eb) and three reflecting barriers (10, 12, 14) placed between the oppositely-disposed transmitting faces of the two probes (Ea and Eb), said object being placed between two (12,14) of said barriers.

Claim 4

A device according to claim 1, wherein said barriers are constituted by wires, screens, grids or strips.

Claim 5

A device according to claim 1, for measuring the dimensions of a hollow object showed with a couplant liquid, wherein said device comprises only a single ultransonic probe (E a ) and just two reflecting barriers (10,12), said barriers both being placed in positions on the path of said ultrasonic pulses produced by said probe at distances from said probe that are less than the distance of said object from said probe, and wherein said electric signal producing means are means for producing electric signals proportional in value to the time interval between reception of the respective echoes from said barriers and for producing electric signals proportional in value to the time intervals between echoes corresponding to reflections from different surfaces of said objects.

Claim 6

A device according to claim 1, for the accurate measurement of radial dimensions of a cylindrical tube, wherein said object whose dimensions are to be measured is a cylindrical tube and said device further comprises means for displacing said tube in a direction parallel to its axis, and in which further, there are N pairs of said ultrasonic probes, placed in a ring around the tube, the two probes of each pair of probes being placed opposite to each other on each side of said tube, said tube having an external radius R 1 , the probes being disposed so as to transmit ultrasonic pulses which propagate in directions perpendicular to the generator-lines of said tube, and in which, further, said device also comprises means for sequentially switching into activity each of the N pairs of probes, and in which further, said barriers are constituted in a form capable of partially reflecting waves from any of said probes without more than partially obstructing wave pulses from said probes traveling to and from said tube, and in which, further, said electric signal producing means are means for producing electrical signals proportional to the interval between echoes respectively corresponding to reflections from said two barriers and means for producing electric signals proportional to the intervals betwen echoes corresponding respectively to reflection from different surfaces of said tube, and in which, further, said electronic processing means includes means responsive to said sequentially switching means for identifying the respective outputs of said processing means relating to each of said pairs of probes, whereby said electronic processing means is enabled to produce electric signals proportional to the external and internal radii of said tube in directions corresponding to each of said N pairs of probes.

Claim 7

A device according to claim 22, wherein the two reflecting barriers are respectively constituted by: a first cylindrical tube of external radius R 2 which is coaxial with the tube being measured, with R 2 > R 1 , the external surface of radius R 2 of said first barrier being located on a portion of the emission ultrasonic field of each probe; and a second cylindrical tube of radius R 3 , with R 3 > R 2 , the external surface of radius R 3 of said second tube being located on a portion of the emission ultrasonic field of each probe.

Claim 8

A device according to claim 5, wherein three pairs of collectors are placed at angular intervals of 120° about the tube to be tested.

Claim 9

A device according to claim 1, wherein, said means for producing electrical signals having values proportional to the time intervals which elapse between reception on said probes (Ea and Eb) of the various echoes corresponding to the reflections of the ultrasonic pulses from said barriers and from said object comprise: a first time-amplitude converter (A a ) having an adjustable gain Kλ 1 which is supplied at the input with electrical pulses corresponding to the first two ultrasonic echoes returned by said first barrier and said second barrier and received by the first probe (Ea) and which delivers at the output a signal equal to Kλ 1 t 1 , where t 1 is the time interval which elapses between the reception of the first two echoes by said first probe (Ea), a second time-amplitude converter (A b ) having an adjustable gain λ which is supplied with electrical pulses corresponding to the two ultrasonic echoes returned by the second barrier and the external surface of the object located opposite to the first probe (Ea) and received by said first probe (Ea) and which delivers at the output a signal equal to λt 2 , where t 2 is the time interval which elapses between reception of said two echoes by said first probe (Ea), and a third time-amplitude converter (A f ) having an adjustable gain λ which is supplied at the input with pulses corresponding to the two ultrasonic echoes returned by said third barrier and the external surface of the object located opposite to said second probe (Eb) and received by said second probe (Eb) and which delivers a signal equal to Kt 5 , where t 5 is the time interval which elapses between reception of said two echoes, and in which said electronic processing means comprise: an adding device (A d ) which is supplied from the outputs of the time-amplitude converters (A b ) and (A c ) and which delivers an output signal u 1 = λ(t 2 + t 5 ), a subtracting device (S a ) which is supplied at the input from the outputs of the time-amplitude converter (A a ) and of the adding device (A d ) and which delivers at the output an output signal u 2 = Kλ 1 t 1 - λ(t 2 + t 5 ), and an amplifier (A e ) supplied from the output of the subtracting device (S a ) and designed to deliver at the output a signal which is a linear function of the dimension of the part as measured along the direction of propagation of the ultrasonic waves.

Claim 10

A device according to claim 8, wherein the gain K of said first converter (A a ) is so adjusted that the output signal of said amplifier (A e ) has a zero value for an object having a known dimension and placed between the two barriers aforesaid.

Claim 11

A device according to claim 9, for measuring the internal and external dimensions of a hollow object, wherein said electric signal producing means further comprise: a fourth time-amplitude converter (A c ) having an adjustable gain k which is supplied at the input with electrical pulses corresponding to the two ultrasonic echoes returned by the external and internal surfaces of the object and received by the first probe (Ea) and which delivers at the output a signal equal to kt 3 where t 3 is the time interval which elapses between reception of said two echoes, and a fifth time-amplitude converter (A g ) having an adjustable gain k which is supplied at the input with electrical pulses corresponding to the two ultrasonic echoes returned by the external and internal surfaces of the object and received by the second probe (Eb) and which delivers at the output a signal equal to kt 6 , where t 6 is the time interval which elapses between reception of said two echoes, and in which said amplifier (A e ) of said processing means is supplied from the outputs of the fourth and fifth time-amplitude converters (A c ) and (A g ) and delivers an output signal u 3 = K(t 3 + t 6 ), and said electronic processing means further comprise: a second subtracting device (S b ) which is supplied by the output signal of said amplifier and by a signal having an adjustable value u 0 and which delivers at the output a signal having a value equal to u 4 = k(t 3 + t 6 ) - u 0 , a third subtracting device (S c ) which is supplied at the input from the output of the second subtracting device (S b ) and from the output of said amplifier (A e ) and delivers at the output a signal which is a linear function of the internal dimension of the object to be measured, along the direction of propagation of the ultrasonic pulses.