Apparatus and method for acoustic monitoring of steam quality and flow

Patent metadata

Field	Value
Publication number	US-2016356744-A1
Application number	US-201615237522-A
Country	US
Kind code	A1
Filing date	Aug 15, 2016
Priority date	Mar 7, 2011
Publication date	Dec 8, 2016
Grant date	—

Abstract

An apparatus and method for noninvasively monitoring steam quality and flow and in pipes or conduits bearing flowing steam, are described. By measuring the acoustic vibrations generated in steam-carrying conduits by the flowing steam either by direct contact with the pipe or remotely thereto, converting the measured acoustic vibrations into a frequency spectrum characteristic of the natural resonance vibrations of the pipe, and monitoring the amplitude and/or the frequency of one or more chosen resonance frequencies, changes in the steam quality in the pipe are determined. The steam flow rate and the steam quality are inversely related, and changes in the steam flow rate are calculated from changes in the steam quality once suitable calibration curves are obtained.

First claim

What is claimed is:

1 . An apparatus for monitoring steam quality at a chosen location in a pipe in which steam is flowing, comprising:
a piezoelectric transducer for detecting sound generated in the pipe by the steam flowing through the pipe at the chosen location; a signal processor for receiving the signal from said piezoelectric transducer and determining at least one acoustic frequency from the natural resonance vibration frequency spectrum of the pipe; and a microprocessor for monitoring the peak amplitude at the at least one acoustic vibration frequency from said signal processor; whereby changes in the steam quality are obtained from changes in the peak amplitude at the at least one acoustic vibration frequency.

2 . The apparatus of claim 1 , wherein said piezoelectric transducer is chosen from lithium niobate, lead zirconate-lead titanate and bismuth titanate crystals.

3 . The apparatus of claim 1 , further comprising a buffer rod in acoustic contact with said pipe.

4 . The apparatus of claim 1 , wherein said signal processor comprises a digital signal processor from which a fast Fourier transform of the detected sound is generated.

5 . The apparatus of claim 4 , wherein said digital signal processor comprises a spectrum analyzer.

6 . An apparatus for monitoring steam quality at a chosen location in a pipe in which steam is flowing, comprising:
a detector spaced-apart from said pipe for detecting sound generated in the pipe by the steam flowing through the pipe at the chosen location; a signal processor for receiving the signal from said detector and determining at least one acoustic frequency from the natural resonance vibration frequency spectrum of the pipe; and a microprocessor for monitoring the peak amplitude at the at least one acoustic vibration frequency from said signal processor; whereby changes in the steam quality are obtained from changes in the peak amplitude at the at least one acoustic vibration frequency.

7 . The apparatus of claim 6 , wherein said detector comprises a microphone.

8 . The apparatus of claim 7 , wherein said microphone comprises a parabolic reflector.

9 . The apparatus of claim 7 , wherein said microphone is chosen from a pencil microphone, a directional microphone and a phased-array microphone.

10 . The apparatus of claim 6 , wherein said detector comprises a laser Doppler vibrometer.

11 . The apparatus of claim 6 , wherein said signal processor comprises a digital signal processor from which a fast Fourier transform of the detected sound is generated.

12 . The apparatus of claim 11 , wherein said digital signal processor comprises a spectrum analyzer.

13 . A method for monitoring steam quality at a chosen location in a pipe in which steam is flowing, comprising the steps of:
detecting sound generated in the pipe by the steam flowing through the pipe at the chosen location; determining at least one acoustic frequency from the natural resonance vibration frequency spectrum of the pipe; and monitoring the frequency of a peak at the at least one acoustic vibration frequency; whereby changes in the steam quality are obtained from changes in the frequency of the peak at the at least one acoustic vibration frequency.

14 . The method of claim 13 , further comprising the step of calculating the change in steam flow rate from the change in steam quality.

15 . The method of claim 13 , wherein said step of detecting sound generated in the pipe is achieved using a microphone.

16 . The method of claim 15 , wherein the microphone comprises a parabolic reflector.

17 . The method of claim 15 , wherein the microphone is chosen from a pencil microphone, a directional microphone and a phased-array microphone.

18 . The method of claim 13 , wherein said step of detecting sound generated in the pipe is achieved using a laser Doppler vibrometer.

19 . The method of claim 13 , wherein said step of detecting sound generated in the pipe is achieved using a piezoelectric transducer in acoustic contact with the pipe.

20 . The method of claim 19 , wherein the piezoelectric transducer is chosen from lithium niobate, lead zirconate-lead titanate and bismuth titanate crystals.

21 . The method of claim 13 , wherein said step of detecting sound generated in the pipe is achieved using a piezoelectric transducer in acoustic contact with a buffer rod in acoustic contact with the pipe.

22 . The method of claim 21 , wherein the piezoelectric transducer is chosen from lithium niobate, lead zirconate-lead titanate, and bismuth titanate crystals.

23 . The method of claim 13 , further comprising the step of generating a fast Fourier transform of the detected sound generated in the pipe.

24 . An apparatus for monitoring steam quality at a chosen location in a pipe in which steam is flowing, comprising:
a piezoelectric transducer for detecting sound generated in the pipe by the steam flowing through the pipe at the chosen location; a signal processor for receiving the signal from said piezoelectric transducer and determining at least one acoustic frequency from the natural resonance vibration frequency spectrum of the pipe; and a microprocessor for monitoring the frequency of a peak at the at least one acoustic vibration frequency from said signal processor; whereby changes in the steam quality are obtained from changes in the frequency of the peak at the at least one acoustic vibration frequency.

25 . The apparatus of claim 24 , wherein said piezoelectric transducer is chosen from lithium niobate, lead zirconate-lead titanate and bismuth titanate crystals.

26 . The apparatus of claim 24 , further comprising a buffer rod in acoustic contact with said pipe.

27 . The apparatus of claim 24 , wherein said signal processor comprises a digital signal processor from which a fast Fourier transform of the detected sound is generated.

28 . The apparatus of claim 27 , wherein said digital signal processor comprises a spectrum analyzer.

29 . An apparatus for monitoring steam quality at a chosen location in a pipe in which steam is flowing, comprising:
a detector spaced-apart from said pipe for detecting sound generated in the pipe by the steam flowing through the pipe at the chosen location; a signal processor for receiving the signal from said detector and determining at least one acoustic frequency from the natural resonance vibration frequency spectrum of the pipe; and a microprocessor for monitoring the frequency of a peak at the at least one acoustic vibration frequency from said signal processor; whereby changes in the steam quality are obtained from changes in the frequency of the peak at the at least one acoustic vibration frequency.

30 . The apparatus of claim 29 , wherein said detector comprises a microphone.

31 . The apparatus of claim 30 , wherein said microphone comprises a parabolic reflector.

32 . The apparatus of claim 30 , wherein said microphone is chosen from a pencil microphone, a directional microphone and a phased-array microphone.

33 . The apparatus of claim 29 , wherein said detector comprises a laser Doppler vibrometer.

34 . The apparatus of claim 29 , wherein said signal processor comprises a digital signal processor from which a fast F

Assignees

• Los Alamos Nat Security Llc

Inventors

• Sinha Dipen N
• Pantea Cristian

Classifications

• G01F1/666 Primary

  by detecting noise and sounds generated by the flowing fluid · CPC title

• G01N29/036 Primary

  by measuring frequency or resonance of acoustic waves · CPC title

• G01N29/02 Primary

  Analysing fluids (using acoustic emission techniques G01N29/14 {; constructional or flow details for analysing fluids G01N29/222; optoacoustic fluid cells G01N29/2425}) · CPC title

• G01F1/66

  by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters · CPC title