Gas concentration and flow rate sensor
First Claim
1. A sensor for detecting concentrations of a gas mixture comprising:
- a chamber bounding the gas mixture, the chamber having a fundamental resonant acoustic frequency varying with the gas concentrations of the mixture therein;
means for detecting acoustic noise in said chamber and producing therefrom a spectrum signal; and
means for measuring the fundamental resonant frequency of said chamber from said spectrum signal, said measured fundamental resonant frequency being a measure of the gas concentrations.
1 Assignment
0 Petitions
Accused Products
Abstract
A gas vapor sensor indicates the relative concentrations and flow rate of a gas mixture. Acoustic noise is generated within a closed chamber by the gas mixture flowing therethrough or by ambient noise sources. The chamber has a fundamental resonant frequency which varies with the vapor concentration. Acoustic frequency components of the noise corresponding to the resonant frequency of the chamber are sharply reinforced and dominate the acoustic spectrum within the chamber. The spectrum is detected and frequency filtered by a pair of dissimilar parallel filters to produce two attenuated outputs. The difference between the attenuated outputs indicates the resonant frequency and is a measure of the vapor concentration. The strength of the acoustic spectrum together with the measured vapor concentration indicates the flow rate of the mixture.
28 Citations
10 Claims
-
1. A sensor for detecting concentrations of a gas mixture comprising:
-
a chamber bounding the gas mixture, the chamber having a fundamental resonant acoustic frequency varying with the gas concentrations of the mixture therein; means for detecting acoustic noise in said chamber and producing therefrom a spectrum signal; and means for measuring the fundamental resonant frequency of said chamber from said spectrum signal, said measured fundamental resonant frequency being a measure of the gas concentrations. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9)
-
-
2. A sensor for simultaneously detecting concentrations and flow rates of a gas mixture comprising:
-
a chamber through which the gas mixture flows, the chamber having an inlet and an outlet and a fundamental resonant acoustic frequency varying with the gas concentrations of the mixture therein; means for detecting acoustic noise in said chamber and producing therefrom a spectrum signal; means for measuring the fundamental resonant frequency of said chamber from said spectrum signal, said measured fundamental resonant frequency being a measure of the gas concentrations; and means for measuring the strength of said spectrum signal, said measured strength being a measure of the gas mixture flow rate corresponding to said gas concentrations.
-
-
10. A method for simultaneously detecting concentrations and flow rates of a gas mixture comprising:
-
passing the gas mixture through a chamber having an inlet and an outlet and a fundamental resonant acoustic frequency varying with the relative gas concentration of the mixture therein; detecting acoustic noise in said chamber and producing therefrom a spectrum signal; measuring the strength of said spectrum signal; filtering said spectrum signal through a pair of parallel filters to produce a pair of attenuated outputs; and measuring the ratio of the difference between the pair of attenuated outputs to the sum of the pair of attenuated outputs, said measured ratio being a measure of the gas concentrations and said measured strength of the spectrum signal being a measure of the gas mixture flow rate corresponding to said gas concentrations.
-
Specification