Methods and systems for measuring concentrations of known components in gas samples using acoustic resonance

• US 10,641,753 B1
• Filed: 10/25/2018
• Issued: 05/05/2020
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Tillotson, Brian
• Primary Examiner(s): Schmitt, Benjamin R
• Application Number:
  US16/170,926
• Publication Number:
  US 20200132632A1
• Time in Patent Office: 558 Days
• Field of Search: 73 232, 73 2401, 73 2406, 73 3105
• CPC Class Codes: G01N 2291/0215 Mixtures of three or more gases, e.g. air
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/22 Details , e.g. general constructional or apparatus details
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/34 Generating the ultrasonic, sonic or infrasonic waves , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01N 29/4436 with a reference signal amplitude comparison G01N29/48
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14
• CPC Class Codes: G01N 33/0009 General constructional details of gas analysers, e.g. portable test equipment devices for withdrawing samples in the gaseous state G01N1/22
• CPC Class Codes: G01N 33/0027 concerning the detector
• CPC Class Codes: G01N 33/004 CO or CO2
• CPC Class Codes: G01N 33/0062 concerning the measuring method or the display, e.g. intermittent measurement or digital display

Abstract

Disclosed are methods and systems for measuring concentration of known components in gas samples using an acoustic resonance technique. A system includes a resonant chamber, a sound generator positioned at and acoustically coupled to an opening of the resonant chamber, and an audio sensor positioned proximate to and in sound communication to the opening and configured to measure an acoustic spectrum. During operation, the sound generator produces a white noise such that the soundwaves of the white noise passes through a gas sample positioned in the resonant chamber. As the soundwaves pass through the gas sample, the audio sensor monitors the frequency spectrum and identifies any resonant frequency that, if present, would correspond to a specific component and the concentration of this component. Specifically, the component concentration is determined from the frequency response.

Claims

1. A system for measuring a concentration of a known component in a gas sample using an acoustic resonance technique, the system comprising:

a resonant chamber, comprising a wall, forming an interior, and an opening extending through the wall to the interior;

a sound generator, positioned at and acoustically coupled to the opening of the resonant chamber and configured to generate white noise and supply the white noise into the interior of the resonant chamber; and

an audio sensor, positioned proximate to and in sound communication to the opening and configured to measure an acoustic spectrum emitted from the interior of the resonant chamber through the opening.

2. The system of claim 1,

wherein the wall of the resonant chamber comprises a movable portion, opposite of the opening and slidably coupled to a fixed portion of the wall,

wherein the opening and the movable portion define a length of the interior of the resonant chamber;

and

wherein the length of the interior is controllably adjustable.

3. The system of claim 2,

wherein the resonant chamber comprises two or more markings;

and

wherein each of the two or more markings represents a resonant wavelength, corresponding to the length of the interior.

4. The system of claim 3,

wherein the wall is formed by a transparent syringe;

and

wherein the movable portion is formed by a piston.

5. The system of claim 1, wherein the sound generator is selected from a group consisting of:

an electronic sound generator,

a combination of a sound source and an airflow generator; and

a combination of a sound source and an airflow supply line.

6. The system of claim 5, wherein the sound source is a reed.

7. The system of claim 5, wherein the airflow generator is selected from the group consisting of a syringe, a compressed air tank, and a compressor.

8. The system of claim 1, further comprising a computer system such that the audio sensor is a part of the computer system and such that the resonant chamber and the sound generator are connected to and supported by the computer system.

9. The system of claim 8, wherein the computer system comprises a controller for analyzing the acoustic spectrum and determining the concentration of the known component in the gas sample.

10. The system of claim 8, wherein the computer system is a mobile phone further comprising an enclosure;

and

wherein the resonant chamber and the sound generator are integrated into the enclosure.

11. A method for measuring a concentration of a known component in a gas sample using a system, comprising a resonant chamber, a sound generator, and an audio sensor, the method comprising:

receiving the gas sample into an interior of the resonant chamber;

generating white noise using the sound generator, positioned at and acoustically coupled to an opening of the resonant chamber such that the white noise propagates to the interior of the resonant chamber; and

capturing an acoustic spectrum using the audio sensor, positioned proximate to and in sound communication to the opening, wherein the acoustic spectrum represents interaction of the white noise with the gas sample received in the interior of the resonant chamber and corresponds to the concentration of the known component in the gas sample.

12. The method of claim 11, further comprising determining, from the acoustic spectrum, the concentration of the known component in the gas sample.

13. The method of claim 12,

wherein determining the concentration of the known component in the gas sample is performed using a formula

14. The method of claim 11, further comprising:

determining a molar mass of the gas sample using a formula

15. The method of claim 11, further comprising performing a calibration of the system using a reference sample, thereby determining a resonant frequency of the reference sample.

16. The method of claim 15, wherein the known component replaces one or more components in the reference sample, thereby forming the gas sample.

17. The method of claim 15, wherein the known component proportionally replaces all components in the reference sample, thereby forming the gas sample.

18. The method of claim 11, further comprising displaying the concentration of the known component in the gas sample on a user interface (UI) component of the system.

19. The method of claim 11, further comprising adjusting a length of the interior of the resonant chamber.

20. The method of claim 19, wherein adjusting the length of the interior comprises changing a position of a movable portion of a wall of the resonant chamber relative to the opening.

21. The method of claim 20, wherein receiving the gas sample into the interior of the resonant chamber comprises changing the position of the movable portion of the wall relative to the opening.

22. The method of claim 11, wherein generating the white noise comprises supplying an airflow to a sound source of the sound generator.