Multi-chambered acoustic sensor for determination gas composition

摘要

A sound velocity sensor is defined by a hermetic multi-chambered enclosure for containing flowing gases and mixtures of gases. The contained flowing gases are acoustically excited and the acoustic energy is measured over a fixed distance between a first sending end of the enclosure and a receiving end. The speed of sound of the gases are determined by comparing the energy transmitted through the flowing gases at various frequencies so as to precisely determine the resonant frequency of the gases flowing through the enclosure. In accordance with the present design, the chambers of the enclosure include internal transition shapes therebetween for optimizing the transmission of acoustic energy through the flowing gases and also enhancing one or more additional resonant modes at higher useful frequencies. The transition shapes used in connection with the sensor can be at least one of parabolic, hyperbolic, linear and exponential in nature.

主权项

1. A sound velocity sensor for analyzing the gas concentration of a flowing mixture of gases, the sensor comprising:
a hermetic enclosure including an interior having a pair of acoustic cavities separated by a constricted region and defining a resonator chamber; gas flowing means, fluidly connected to the enclosure, for flowing a gas mixture through the resonator chamber, the gas mixture including nitrogen as a primary carrier gas; acoustic driving means at a first sending end of the enclosure for transmitting an acoustic signal through the gas mixture flowing through the enclosure; receiving means at a second receiving end of the enclosure for receiving the acoustic signal; a processor configured to process the received acoustic signal; and means for detecting a resonant frequency of the flowing gas mixture and determining the composition of the gas mixture in which a first acoustic cavity of said enclosure is defined by an inwardly curved and tapering shape extending from the first sending end and an opposing second acoustic cavity is defined by an outwardly curved and tapering shape extending to the second receiving end with a narrow constricted region being defined between the first and second acoustic cavities for optimizing the transmission of acoustic energy through the flowing gas mixture and enhancing at least one additional resonant mode at higher useful frequencies.