Aerosol discriminator for particle discrimination
AssigneeAlliedSignal Inc.
InventorsRichard K. Morey, Donald R. Chansky, Jr., Douglas J. Wylie, Mark A. Mormino, Joseph F. Halik, IV
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Abstract
An optical particle counter generates a signal indicating an amount of radiation scattered by aerosols in a sample flow. Smoke can be discriminated from other aerosols in the sample flow by analyzing the AC component of the signal. Smoke has a much higher signal-to-noise ratio than that of larger particles such as dust and fog.
Claims24
A method of analyzing a scatter signal from an optical particle counter, said scatter signal indicating an amount of radiation scattered by a sample flow, said method comprising the steps of:
- determining the AC component of said scatter signal;
- and
- comparing said AC component to a reference signal indicating the amount of scatter caused by a particular aerosol.
Apparatus for analyzing a scatter signal from an optical particle counter, said scatter signal indicating an amount of radiation scattered by a sample flow, said apparatus comprising:
- sampling means for sampling said scatter signal;
- first processing means, responsive to said sampling means, for forming a distribution of samples;
- second processing means, responsive to said first processing means, for generating a signal indicating a variance of said distribution;
- third processing means, responsive to said second processing means, for generating a discriminator signal from said variance signal;
- and
- comparing means, responsive to said third processing means, for comparing said discriminator signal to a reference signal.
Apparatus for analyzing a scatter signal from an optical particle counter, said scatter signal indicating an amount of radiation scattered by a sample flow, said apparatus comprising:
- band pass filter means for determining the AC component of said scatter signal;
- and
- first comparing means, responsive to an output of said band pass filter means, for comparing said AC component to a first reference signal corresponding to a particular aerosol.
Dependencies are inferred from the claim text.