US 10,852,168 B2Granted

Method of measuring time of flight of an ultrasound pulse

AssigneePCME Limited

InventorsNeil D'Souza-Mathew, Robert Fryers, Roger Millington, David Unitt

Life of this patent

Estimating the term…

Loading patent…

Abstract

Method and apparatus relating to ultrasound flow probes Measurement of time of flight of ultrasound pulses comprises: transmitting the pulses across a fluid flow; detecting a waveform (200) of the pulses, generating a cross-correlation between the waveform (200) and a tone (210) and identifying a plurality of peaks (220) in the cross-correlation; fitting a curve template (310) to the waveform at locations (300) corresponding to the peaks (220) and identifying the location (330) of the minimum error; performing a further cross-correlation (420) between the waveform (200) and the tone (210) over only a portion of the waveform (200) containing the minimum error location (330); and determining the temporal location corresponding to the maximum (430) of the further cross-correlation (430).

Claims16

Dependent claims

A method of measuring time of flight of a pulse of ultrasound in a fluid flow, the pulse having an ultrasonic frequency, the method comprising:

(1) transmitting the ultrasound pulse across the fluid flow;
(2) detecting the ultrasound pulse after transmission, the detected pulse being a first waveform comprising a first plurality of data points, generating a cross-correlation between the first waveform and a tone at the ultrasonic frequency, and identifying a plurality of peaks in the cross-correlation;
(3) fitting a curve template to the first waveform at temporal locations corresponding to the peaks in the cross-correlation and identifying a first temporal location in the first waveform of the minimum error of the fit, the first temporal location being within the temporal locations;
(4) performing a further cross-correlation between the first waveform and the tone, the further cross-correlation being carried out over only a portion of the first waveform, utilizing at least some of the data points of the first plurality of data points, the portion containing the first temporal location corresponding to the minimum error of the fit;
and
(5) determining a second temporal location in the first waveform corresponding to the maximum of the further cross-correlation and thereby obtaining a measurement of the time of flight of the pulses, the second temporal location being within said portion of the first waveform containing the first temporal location.

3 more elements

An ultrasound flow probe for measuring the flow velocity of a fluid flowing in a conduit, the probe comprising:

(i) a pulse transmitter for transmitting, from an upstream position, across the fluid flow, a first ultrasound pulse, the first ultrasound pulse having an ultrasound frequency;
(ii) a detector for detecting the first ultrasound pulse at a downstream position, the detected pulse being a first waveform comprising a first plurality of data points;
(iii) a pulse transmitter for transmitting, from the downstream position, across the fluid flow, a second ultrasound pulse, the second ultrasound pulse having a waveform having an ultrasound frequency and a rising edge;
(iv) a detector for detecting the second pulse at the upstream position, the detected pulse being a second waveform comprising a second plurality of data points;
and
(v) a processing unit configured to, for the first waveform and second waveform:
(A) generate a cross-correlation between the waveform of the detected pulse and a tone at the ultrasonic frequency and identify a plurality of peaks in the cross-correlation;
(B) fit a curve template to the waveform at temporal locations corresponding to the peaks in the cross-correlation and identify a first temporal location in the waveform of the minimum error of the fit, the first temporal location being within the temporal locations;
(C) perform a further cross-correlation between the waveform and the tone, the further cross-correlation being carried out over only a portion of the waveform, the portion containing the first temporal location corresponding to the minimum error of the fit;
and
(D) determine a second temporal location in the waveform corresponding to the maximum of the further cross-correlation and thereby obtain a measurement of the time of flight of the pulse, the second temporal location being within said portion of the first waveform containing the first temporal location;
and
(E) calculate the flow velocity using the measurements of the times of flight of the first and second pulses.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/322,456Filed 29 Jun 2015
Priority: GB 1411701.41 Jul 2014
Published: US 2017/0138773 A118 May 2017
Granted: 1 Dec 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01F 1/667
By measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters: arrangements of…
G01F 1/662
By measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters: constructional details
G01P 5/248
By measuring transit time of acoustical waves: by measuring phase differences
G01F 23/2962
Acoustic waves: measuring transit time of reflected waves