US 11,885,795 B2Granted

Method for measuring breath alcohol concentration and apparatus therefor

AssigneeAlco System Sweden AB

InventorsNigel Evans, Leigh Wallington

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Abstract

The present invention relates to a method and apparatus for measuring breath alcohol concentration of a user. A flow of an expired breath sample is passed through a fuel cell sensor giving an output signal proportional to the amount of alcohol present in the breath sample. By measuring the flow rate, the volume of the breath sample may be calculated, whereas the breath alcohol concentration is calculated based on the fuel cell output signal. Both the sample volume and the breath alcohol concentration values are continually updated by integrating the measured instantaneous flow rate and the fuel cell output signal over time. If the user stops blowing, flow compensation is performed to obtain a compensated fuel cell output signal using a stored calibration volume. Hence, an improved method for accurately measuring the breath alcohol concentration of a test person is achieved, capable of handling varied expired volumes of breath, which obviates the need for a sampling mechanism.

Claims18

Dependent claims

A method of measuring a breath alcohol concentration (BrAC) of a user with a reduced lung capacity, the method measuring a flow rate (Q) of a breath sample, the breath sample having a breath sample volume Vb that is variable, the method being performable without a sampling mechanism configured to measure a predetermined sample volume, the method comprising the steps of:

(I) receiving a flow of an expired breath sample from the user into an inlet tube, the inlet tube being adjacent to a proximal end of a first channel;
(II) receiving a first portion of the breath sample from the inlet tube into the first channel at the proximal end, wherein the first channel includes a closed distal end opposite the proximal end, and measuring an instantaneous flow rate (Q) of the first portion of the breath sample with a flow meter, the flow meter being disposed closer to the closed distal end of the first channel than to the proximal end;
(III) triggering a microcontroller in electronic communication with the flow meter to calculate the breath sample volume Vb based on the measured instantaneous flow rate (Q);
(IV) receiving a second portion of the breath sample from the first channel into a second channel at a second channel entrance disposed closer to the proximal end of the first channel than to the distal end, and passing the second portion of the breath sample into a fuel cell sensor in electronic communication with the microcontroller and providing a fuel cell sensor output signal (FCout);
(V) actuating the microcontroller to calculate the breath alcohol concentration (BrAC) based on the output signal (FCout) of the fuel cell sensor;
(VI) updating continually the breath sample volume (Vb) and the breath alcohol concentration (BrAC) via the microcontroller by integrating the measured instantaneous flow rate (Q) and the fuel cell output signal (FCout) over time, irrespective of the breath sample volume (Vb);
(VII) determining, via the microcontroller, an instant at which the flow of the expired breath sample from the user terminates, such that a final collected breath sample volume (Vb) is established;
and
(VIII) actuating the microcontroller to compensate the fuel cell sensor output signal (FCout) using a stored calibration volume (Vcal) to obtain a final compensated fuel cell output signal (FCcomp), before calculating the breath alcohol concentration (BrAC) again when the user stops blowing;
wherein said compensating is performed using a formula:
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such that the breath alcohol concentration (BrAC) is accurately calculated even when the breath sample volume (Vb) is varied.

37 more elements

An apparatus for measuring breath alcohol concentration (BrAC) of a user with a reduced lung capacity, the device configured to measure a flow rate (Q) of a breath sample, the breath sample having a breath sample volume Vb that is variable, the apparatus being operable without a sampling mechanism configured to measure a predetermined sampling volume, the apparatus comprising:

(I) an inlet tube configured to receive an expired breath sample of a user;
(II) a first channel and a second channel, the first channel having a proximal end adjacent to the inlet tube and a closed distal end opposite the proximal end, the second channel having a second channel entrance disposed closer to the proximal end of the first channel than to the distal end of the first channel;
(III) a flow meter configured to measure an instantaneous flow rate (Q) of a first portion of the breath sample received in the first channel, the flow meter being disposed closer to the closed distal end than to the proximal end;
(IV) a fuel cell sensor in fluid communication with the second channel and configured to measure a second portion of the breath sample received in the second channel at the second channel entrance from the first channel;
and
(V) a microcontroller in electronic communication with the flow meter and the fuel cell sensor, the microcontroller being configured to:
(a) calculate the breath alcohol concentration (BrAC) based on an output signal (FCout) of the fuel cell sensor;
and
(b) calculate the breath sample volume (Vb) based on the measured instantaneous flow rate (Q);
wherein the microcontroller is further adapted to:
(c) to continually update the breath sample volume (Vb) and the breath alcohol concentration (BrAC) by integrating the measured instantaneous flow rate (Q) and the fuel cell output signal (FCout) over time, irrespective of the breath sample volume (Vb);
(d) determine an instant at which the expired breath sample terminates and calculate the breath sample volume (Vb) at this instant;
and
(e) perform a flow compensation to obtain a final compensated fuel cell output signal (FCcomp) using a stored calibration volume (Vcal) wherein said flow compensation is performed using a formula:
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40 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/192,147Filed 4 Mar 2021 · continuation
Published: US 2021/0270804 A12 Sep 2021
Granted: 30 Jan 2024
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G01N 33/4972
Of gaseous biological material, e.g. breath: determining alcohol content
A61B 5/087
Measuring devices for evaluating the respiratory organs: measuring breath flow
A61B 5/097
Measuring devices for evaluating the respiratory organs: devices for facilitating collection of breath or for directing breath into or through…
A61B 5/7225
Signal processing specially adapted for physiological signals or for diagnostic purposes: details of analogue processing, e.g. isolation…

Family

PCT/SE2010/051421Parent of this continuation · filed 20 Dec 2010
US 2021/0270804 A1Pre-grant publication · published 2 Sep 2021
Application13/995,377Parent of this continuation
US 10,942,168 B2Parent of this continuation
US 2013/0281873 A1Published application
US 11,885,795 B2This patent

From the US filing history. Foreign family members aren’t listed.