Acoustic sensor for in-line continuous monitoring of gasses
First Claim
1. An acoustic cell for analyzing the gas concentration of a gas flowing gas mixture, said cell comprising:
- a cell housing;
said cell housing including an interior having a plurality of adjacently coupled acoustic cavities which defines a resonator chamber;
gas flowing means, fluidly connected to said cell housing, for flowing a gas mixture through said resonator chamber;
acoustic driving means at a first end of said cell housing for sending an acoustic signal through said gas mixture flowing through said cell housing;
receiving means at a second end of said cell housing for receiving said acoustic signal;
processing means for processing said received acoustic signal;
means for detecting the resonant frequency of said flowing gas mixture; and
for determining the composition of said gas mixture, andmeans for acoustically isolating at least one of said driving means and said receiving means from said cell.
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Accused Products
Abstract
An acoustic cell includes multiple acoustic cavities fluidly coupled together. At least two of the acoustic cavities have unequal lengths and cross sections. End segments of the acoustic cell are uniformly cylindrically shaped or conically shaped. A driver transducer at one end of the acoustic cell and a receiver transducer at another end of the acoustic cell are acoustically isolated from the acoustic cell. A pair of preferably metallic isolation diaphragms transmit acoustic signals to and from the transducers without significantly altering the phase-frequency characteristics of the acoustic signals. The acoustic cell operates as an acoustic resonator operating at frequencies lower than any possible self-resonance frequencies of the isolation diaphragms or the driver and receiver transducers. When a binary gas is flowed through the cell, a processor detects a resonant frequency of the gas within the cell to determine a composition of the gas.
54 Citations
22 Claims
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1. An acoustic cell for analyzing the gas concentration of a gas flowing gas mixture, said cell comprising:
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a cell housing; said cell housing including an interior having a plurality of adjacently coupled acoustic cavities which defines a resonator chamber; gas flowing means, fluidly connected to said cell housing, for flowing a gas mixture through said resonator chamber; acoustic driving means at a first end of said cell housing for sending an acoustic signal through said gas mixture flowing through said cell housing; receiving means at a second end of said cell housing for receiving said acoustic signal; processing means for processing said received acoustic signal; means for detecting the resonant frequency of said flowing gas mixture; and
for determining the composition of said gas mixture, andmeans for acoustically isolating at least one of said driving means and said receiving means from said cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An acoustic sensor for analyzing the gas composition of a flowing gas mixture, said sensor comprising:
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a housing; said housing including an interior having a plurality of acoustic cavities defining a resonator chamber; flowing means, fluidly connected to said housing, for flowing a gas mixture through said housing; driver transducing means at a first end of said housing for receiving a driving electrical signal, converting said driving electrical signal to a driving acoustic signal, and sending said driving acoustic signal through said resonator chamber; receiver transducing means at a second end of said housing for receiving a received acoustic signal, converting said received acoustic signal to a received electrical signal, and outputting said received electrical signal; means for acoustically isolating at least one of said driver transducing means and said receiver transducing means from the remainder of the sensor; processing means for sending said driving electrical signal to said driver transducing means and for receiving said received electrical signal outputted by said receiver transducing means; means for varying a frequency of said driving acoustic signal; and means for detecting a resonance frequency associated with said gas mixture; wherein said processing means includes means for determining a composition of said gas mixture. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method for determining the composition of a gas mixture, said method comprising the steps of:
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providing an acoustic cell having a plurality of acoustic cavities; flowing a gas mixture through said acoustic cell; receiving a driving electrical signal from a digital signal controller; converting said driving electrical signal to a driving acoustic signal; sending said driving acoustic signal through said gas mixture flowing through said acoustic cell from driving means provided in said acoustic cell; receiving, using receiving means disposed in an opposite end of said cell, a received acoustic signal after the step of sending said driving signal through said gas mixture; acoustically isolating at least one of the sending means and receiving means from the remainder of said cell prior to sending said acoustic signal; converting said received acoustic signal to a received electrical signal; outputting said received electrical signal to said digital signal controller; processing, within said digital signal controller, said received electrical signal to detect a resonance frequency associated with said gas mixture; and determining, based on said resonance frequency, the composition of said gas mixture.
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Specification