Method of identifying a gas
AssigneeIndustrial Scientific Corporation
InventorP. Richard Warburton
Life of this patent
Estimating the term…
Abstract
A method and apparatus for identifying an unknown reactive gas in a carrier gas, utilizing a sensor with a diffusion limited inlet. After a signal is established for the carrier gas, a flow of the mixture of carrier gas and reactive gas is passed to the sensor and a steady state signal S is established. Then, the input to and output from the sensor are closed, and the steady state signal decays as a known volume of reactive gas is consumed. The decay curve of the signal is integrated to produce an integrated response .SIGMA., and the ratio S/.SIGMA. is proportional to the diffusion coefficient for the reactive gas. By comparing this ratio to the ratio for a known reactive gas, the identity of the unknown reactive gas can be determined.
Claims10
Method for identifying a reactive gas in a carrier gas, comprising the steps of:
- obtaining a detector which generates an electrical signal upon exposure to the gas;
- positioning said detector to accept gas from a manifold of defined volume with a diffusion barrier between the detector and the manifold;
- determining an output signal from the detector for the carrier gas without the reactive gas;
- directing the reactive gas and carrier gas through an inlet into the manifold, obtaining a steady state signal S from the detector indicating presence of the reactive gas and exhausting carrier gas and reactive gas from the manifold through an outlet;
- closing the inlet and outlet, and permitting reactive gas in the manifold to diffuse through the diffusion barrier for analysis, determining a decay profile as the steady state signal is being reduced vs. time to the output signal for the carrier gas as reactive gas is consumed;
- determining from the steady state signal and decay profile a diffusion coefficient for the reactive gas, and identifying the reactive gas from the diffusion coefficient.
Dependencies are inferred from the claim text.