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System and method for determining a concentration of gas in a confined space

  • US 9,448,186 B2
  • Filed: 12/08/2011
  • Issued: 09/20/2016
  • Est. Priority Date: 12/08/2011
  • Status: Active Grant
First Claim
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1. A system for determining a concentration of gas in a confined space, said system comprising:

  • a first frequency generator for generating a first radio frequency (RF) signal;

    a first antenna electrically connected to said first frequency generator for transmitting the first RF signal across the confined space;

    a second antenna for receiving the first RF signal;

    a first RF signal power detector for detecting the power of the first RF signal prior to transmission through the confined space and generating a first power signal corresponding to the first RF signal prior to transmission;

    a second RF signal power detector for detecting the power of the first RF signal received at said second antenna and generating a second power signal corresponding to the first RF signal received at said second antenna;

    a first comparator circuit in communication with said first and second RF signal power detectors for determining a concentration of oxygen in the confined space based on at least the first power signal and the second power signal;

    at least one thermal reference device for sensing a temperature;

    a temperature compensation comparator circuit in communication with said at least one thermal reference device, said first RF signal power detector for adjusting the first power signal to compensate for the temperature, and said second RF signal power detector for adjusting the second power signal to compensate for the temperature;

    a second frequency generator for generating a second RF signal;

    a third antenna electrically connected to said second frequency generator for transmitting the second RF signal across the confined space;

    a fourth antenna for receiving the RF signal; and

    a sixth comparator circuit in communication with said second frequency generator and said fourth antenna for determining a concentration of water vapor in the confined space based on at least the second RF signal prior to transmission through the confined space and the second RF signal received by said fourth antenna,wherein said first comparator circuit is in communication with said sixth comparator circuit for determining a concentration of water vapor in the confined space and determining a concentration of oxygen in the confined space based on at least the power signals corresponding to the first RF signal and the concentration of water vapor in the confined space.

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