Ultrasonic measurement

Patent metadata

Field	Value
Publication number	US-2016202052-A1
Application number	US-201414916716-A
Country	US
Kind code	A1
Filing date	Sep 23, 2014
Priority date	Sep 30, 2013
Publication date	Jul 14, 2016
Grant date	—

Abstract

Ultrasonic measurement apparatus 10 includes a transmitter 14 to transmit an ultrasonic signal 16 into an item 12 . A receiver 18 receives echoes 20 from the item 12 . The apparatus 10 measures the echo 20 and makes a comparison with another echo to extract information relating to a deposit of additional material at a surface of the item 12 . For example, tribofilms or deposits may grow on the surface of the item 12 during use. A comparison of the echo, with previous echoes, allows the additional material to be detected and/or characterised.

First claim

1 . A method of ultrasonic measurement, the method comprising the steps of:
causing an ultrasonic signal to be transmitted into an item; causing an echo of the transmitted ultrasonic signal to be received from the item; measuring the echo; and undertaking a comparison with another echo to extract information relating to additional material at a surface of the item.

2 . A method according to claim 1 , wherein echoes are repeatedly measured for comparison as aforesaid to extract information relating to additional material.

3 . A method according to claim 1 or 2 , wherein the frequency spectrum of the echo is measured for comparison with another frequency spectrum.

4 . A method according to claim 3 , wherein information is extracted by comparing the shapes of the frequency spectra.

5 . A method according to claim 4 , wherein the comparison of shapes of the frequency spectra is used to characterise the composition of the additional material.

6 . A method according to claim 4 or 5 , wherein the frequency spectrum of an echo measured in the item in the absence of additional material is subtracted from the frequency spectrum of an echo measured subsequently, to create a difference spectrum which is used to characterise the additional material.

7 . A method according to claim 6 , wherein the difference spectrum indicates the material of the additional material.

8 . A method according to any of claims 1 to 7 , wherein the frequency spectrum of the echo is obtained by an FFT analysis.

9 . A method according to any of claims 1 to 8 , wherein a measurement indicative of the energy returned in the echo is made.

10 . A method according to claim 9 , wherein the energy measurement is used to indicate the thickness of the additional material.

11 . A method according to claim 9 or 10 , wherein the energy measurement is made by measuring the maximum amplitude of the echo.

12 . A method according to claim 9 , 10 or 11 , wherein the energy measurement is made by measuring the difference between the maximum and minimum values of the echo.

13 . A method according to claim 9 or 10 , wherein the energy measurement is made by an integration procedure.

14 . A method according to claim 13 , wherein the integration is applied to the echo in the time domain.

15 . A method according to claim 14 , wherein the integration is applied to a FFT of the echo.

16 . A method according to any preceding claim, wherein the transmitted ultrasound signal includes a spectrum of frequencies.

17 . A method according to any preceding claim, wherein the said another echo is an echo measured previously from the same item.

18 . A method according to any of claims 1 to 16 , wherein the said another echo is an echo derived by a mathematical model of the change.

19 . A method according to claim 17 , wherein the mathematical model is based on the geometry and material properties of the item and of the additional material at the surface.

20 . A method according to any preceding claim, wherein the steps of transmitting and receiving are repeated to measure a plurality of echoes, the plurality of echoes being combined for comparison with the said another echo.

21 . A method according to any preceding claim, wherein the item is a part having a surface within an engine.

22 . A method according to any preceding claim, where the transmitted signal includes ultrasound at a frequency between 0.5 MHz and 100 MHz, such as 10 MHz.

23 . Apparatus for ultrasonic measurement of an item, comprising:
a transmitter operable to transmit an ultrasonic signal into the item; a receiver operable to receive from the item an echo of the transmitted signal; and the apparatus being operable to measure the echo and to make a comparison with another echo to extract information relating to additional material at a surface of the item.

24 . Apparatus according to claim 23 , wherein echoes are repeatedly measured for comparison as aforesaid to extract information relating to additional material.

25 . Apparatus according to claim 22 or 24 , wherein the frequency spectrum of the echo is measured for comparison with another frequency spectrum.

26 . Apparatus according to claim 25 , wherein the apparatus is operable to extract information by comparing the shapes of the frequency spectra.

27 . Apparatus according to claim 26 , wherein the comparison of shapes of the frequency spectra is used to characterise the composition of the additional material.

28 . Apparatus according to claim 26 or 27 , wherein the frequency spectrum of an echo measured in the item in the absence of additional material is subtracted from the frequency spectrum of an echo measured subsequently, to create a difference spectrum which is used to characterise the additional material.

29 . Apparatus according to claim 28 , wherein the difference spectrum indicates the material of the additional material.

30 . Apparatus according to any of claims 23 to 29 , wherein the transmitter is operable to transmit an ultrasound signal which includes a spectrum of frequencies.

31 . Apparatus according to any of claims 23 to 30 , operable to obtain the frequency spectrum of the echo by an FFT analysis.

32 . Apparatus according to any of claims 23 to 31 , wherein a measurement indicative of the energy returned in the echo is made.

33 . Apparatus according to claim 32 , wherein the energy measurement is used to indicate the thickness of the additional material.

34 . Apparatus according to claim 32 or 33 , wherein the energy measurement is made by measuring the maximum amplitude of the echo.

35 . Apparatus according to claim 32 , 33 or 34 , wherein the energy measurement is made by measuring the difference between the maximum and minimum values of the echo.

36 . Apparatus according to claim 32 or 33 , wherein the energy measurement is made by an integration procedure.

37 . Apparatus according to claim 36 , wherein the integration is applied to the echo in the time domain.

38 . Apparatus according to claim 37 , wherein the integration is applied to a FFT of the echo.

39 . Apparatus according to any of claims 23 to 38 , wherein the said another echo is an echo measured previously from the same item.

40 . Apparatus according to any of claims 23 to 38 , wherein the said another echo is an echo derived by a mathematical model of the change.

41 . Apparatus according to any of claims 23 to 40 , operable to repeat the steps of transmitting and receiving to measure a plurality of echoes, and further operable to combine the plurality of echoes comparison with the said another echo.

42 . Apparatus according to any of claims 23 to 41 , wherein the item is a part having a surface within an engine.

43 . Apparatus according to any of claims 23 to 42 , where the transmitter is operable to transmit a signal which includes ultrasound at a frequency between 0.5 MHz and 100 MHz, such as 10 MHz.

44 . Software which, when installed on a computer system, is operable to perform the whole

Assignees

• Lubrizol Corp

Inventors

• Smith Oliver
• Sutton Michael R

Classifications

• G01N2291/02854

  Length, thickness · CPC title

• G01N29/36

  Detecting the response signal {, e.g. electronic circuits specially adapted therefor} · CPC title

• G01N29/12

  by measuring frequency or resonance of acoustic waves {(measuring frequency or resonant frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04, G01H13/00; acoustic resonators G10K11/04; vibration or shock testing of structures G01M7/00)} · CPC title

• G01N29/46

  by spectral analysis, e.g. Fourier analysis {or wavelet analysis (spectral signal processing per se G06F17/14)} · CPC title

• G01N29/11 Primary

  by measuring attenuation of acoustic waves · CPC title