# US 10,309,772 B2 · Ultrasonic thickness reduction inspection method/apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,772 B2 - Document ID: US10309772B2 - Status: Granted - Kind: B2 - Application number: 15/360,010 - Filed: 2016-11-23 - Published: 2017-06-01 - Granted: 2019-06-04 - Earliest claimed: 2015-11-27 - Assignees: Hitachi-GE Nuclear Energy, Ltd. - Applicants: Hitachi-GE Nuclear Energy, Ltd. - Inventors: Sou Kitazawa; Naoyuki Kono; Shinobu Okido - Web page: https://patentgrep.com/patent/US10309772B2 ## CPC - G01B 17/02: for measuring thickness - G01N 29/04: Analysing solids (using acoustic emission techniques G01N29/14) - G01N 29/11: by measuring attenuation of acoustic waves - G01N 29/343: {pulse waves, e.g. particular sequence of pulses, bursts} - G01N 29/348: {with frequency characteristics, e.g. single frequency signals, chirp signals (measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00)} - G01N 29/4436: {with a reference signal (amplitude comparison G01N29/48)} - G01N 29/50: using auto-correlation techniques or cross-correlation techniques - G01N 2291/015: Attenuation, scattering - G01N 2291/0258: Structural degradation, e.g. fatigue of composites, ageing of oils - G01N 2291/02854: Length, thickness - G01N 2291/044: Internal reflections (echoes), e.g. on walls or defects - G01N 2291/262: Linear objects - G01N 2291/2634: cylindrical from outside - G01N 2291/2636: cylindrical from inside - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract Chirp waves generated in a transmitting/receiving unit is supplied to ultrasonic sensors. Signals output from the ultrasonic sensors are supplied to the transmitting/receiving unit and summed in a signal processing/recording unit. The signal processing/recording unit performs mutual correlation processing between the summed signals and the chirp waves and calculates a peak generation time difference. Necessity of exchanging a pipe is determined by calculating and recording the thickness of a pipe from the calculated time difference and calculating a difference between thicknesses measured in the past and the present. ## Claims ### Claim 1 An ultrasonic thickness reduction inspection method, comprising: disposing a plurality of ultrasonic sensors on a surface of an inspection target; exciting the plurality of ultrasonic sensors by a frequency modulated wave signal in which a frequency is changed with time; supplying ultrasonic waves to an inside of the inspection target; receiving signals in which the plurality of ultrasonic sensors is excited by a plurality of echoes from the inside of the inspection target by the ultrasonic waves supplied to the inside of the inspection target; summing the plurality of received echo signals; calculating, from cross correlation between the signals summing the plurality of echo signals and the frequency modulated wave signal, a time difference between a first peak of the summed signals and a first peak of the frequency modulated wave signal; and detecting a change in a thickness of the inspection target based on the calculated time difference. ### Claim 2 (depends on 1) The ultrasonic thickness reduction inspection method according to claim 1, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in a circumferential direction of the pipe. ### Claim 3 (depends on 1) The ultrasonic thickness reduction inspection method according to claim 1, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in an axial direction of the pipe. ### Claim 4 (depends on 1) The ultrasonic thickness reduction inspection method according to claim 1, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in a circumferential direction and an axial direction of the pipe. ### Claim 5 (depends on 1) The ultrasonic thickness reduction inspection method according to claim 1, wherein, by electromagnetic induction generated between a plurality of coils disposed opposite to each other, signals are received which are generated when the frequency modulated wave signals of the plurality of ultrasonic sensors are excited, and the plurality of ultrasonic sensors is excited by the plurality of echoes from the inside of the inspection target. ### Claim 6 (depends on 1) The ultrasonic thickness reduction inspection method according to claim 1, wherein a first coil connected to the plurality of ultrasonic sensors, a second coil disposed opposite to the first coil, a third coil electrically connected to the second coil via a metal protection material, and a fourth coil disposed opposite to the third coil are disposed, and by electromagnetic induction between the first coil and the second coil and electromagnetic induction between the third coil and the fourth coil, signals are received which are generated when the plurality of ultrasonic sensors is excited by frequency modulated wave signals, and the plurality of ultrasonic sensors is excited by the plurality of echoes from the inside of the inspection target. ### Claim 7 An ultrasonic thickness reduction inspection apparatus, comprising: a plurality of ultrasonic sensors disposed on a surface of an inspection target; a transmitter/receiver configured to excite the plurality of ultrasonic sensors by a frequency modulated wave signal in which a frequency is changed with time, to supply ultrasonic waves to an inside of the inspection target, and to receive signals in which the plurality of ultrasonic sensors is excited by a plurality of echoes from the inside of the inspection target by the ultrasonic waves supplied to the inside of the inspection target; and a signal processor/recorder configured to sum the plurality of echo signals received by the transmitter/receiver, to calculate a time difference between a first peak of the summed signal and a first peak of the frequency modulated wave signal from cross correlation between signals summing the plurality of echo signals and the frequency modulated wave signal, and to detect a change in a thickness of the inspection target based on the calculated time difference. ### Claim 8 (depends on 7) The ultrasonic thickness reduction inspection apparatus according to claim 7, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in a circumferential direction of the pipe. ### Claim 9 (depends on 7) The ultrasonic thickness reduction inspection apparatus according to claim 7, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in an axial direction of the pipe. ### Claim 10 (depends on 7) The ultrasonic thickness reduction inspection apparatus according to claim 7, wherein the inspection target is a pipe, and the plurality of ultrasonic sensors is disposed side by side in a circumferential direction and an axial direction of the pipe. ### Claim 11 (depends on 7) The ultrasonic thickness reduction inspection apparatus according to claim 7, further comprising: a first coil connected to the plurality of ultrasonic sensors; and a second coil disposed opposite to the first coil and connected to the transmitter/receiver, wherein, by electromagnetic induction generated between the first coil and the second coil, signals are received which is generated when the plurality of ultrasonic sensors is excited by a frequency modulated wave signal, and the plurality of ultrasonic sensors is excited by the plurality of echoes from the inside of the inspection target. ### Claim 12 (depends on 7) The ultrasonic thickness reduction inspection apparatus according to claim 7, further comprising: a first coil connected to the plurality of ultrasonic sensors; a second coil disposed opposite to the first coil; a third coil electrically connected to the second coil via a metal protection material; and a fourth coil disposed opposite to the third coil and connected to the transmitter/receiver, wherein, by electromagnetic induction generated between the first coil and the second coil and electromagnetic induction between the third coil and the fourth coil, signals are received which are generated when the plurality of ultrasonic sensors is excited by a frequency modulated wave signal, and the plurality of ultrasonic sensors is excited by the plurality of echoes from the inside of the inspection target.