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US 8,289,178 B2Granted
Electro/optical smoke analyzer
AssigneeVolution
InventorsMichael S. Slemon, Charles S. Slemon
Life of this patent
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Abstract
A system for analyzing smoke has a plurality of units, wherein each unit includes an optical emitter for alternately directing horizontally and vertically polarized light along a beam path, and into a smoke cloud, to generate scattered light. A horizontally polarized detector and a vertically polarized detector are positioned at different locations, but at a same distance and scattering angle relative to the beam path. Each unit has a different wavelength. A computer receives signals from the detectors of all units, in response to each emitter, for analysis of the smoke.
Claims16
An optical unit for a smoke analyzer system which comprises:
- an optical emitter (E) for alternately directing a beam of horizontally polarized light (λH), and a beam of vertically polarized light (λV) along a beam path through a smoke cloud;
- a horizontally polarized detector (DH) positioned at a scattering angle (θ) from the beam path for generating a signal SHH in response to λH, and for generating a signal SVH in response to λV;
- a vertically polarized detector (DV) positioned at the scattering angle (θ) opposite the beam path from DH for generating a signal SHV in response to λH, and for generating a signal SVV in response to λV;
- an oscillator connected to the emitter to establish a blink rate for transmissions of λH and λV from the emitter;
- a pre-filter connected to the detector DV and to the detector DH to filter noise from outputs of the respective detectors DV and DH , wherein the pre-filter filters a substantially d.c. component (white noise) from the outputs of the respective detectors DV and DH;
- a synchronous demodulator connected in series with the pre-filter and connected directly to the oscillator for tracking the blink rate of the emitter during generation of the signals SHH, SHV, SVH, and SVV;
- and
- a computer for evaluating the signals SHH, SHV, SVH, and SVV for analysis of the smoke.
5 more elements
A system for analyzing smoke which comprises:
- an emitter for directing polarized light along a beam path, wherein the emitter is positioned on a circumference of a circle and the beam path is directed along a diameter of the circle, and further wherein the light is near monochromatic and has a wavelength (λ);
- a plurality of respectively polarized detectors positioned at predetermined locations on the circumference of the circle to generate signals (S) in response to light from the emitter and wherein the circumference is divided into twelve sectors of an equal arc length (θ=30°), with detectors positioned on opposite sides of the beam path at locations of θ, 3θ and 5θ arc lengths from the emitter;
- and
- a computer for evaluating the signals (S) for analysis of the smoke.
1 more element
A method for using a system to analyze smoke which comprises the steps of:
- establishing the system by positioning three emitters and six detectors on a circumference of a circle divided into twelve equal sectors, each of arc length θ, wherein the first emitter is positioned to alternately direct a beam of horizontally polarized light of wavelength λH and a beam of vertically polarized light of wavelength λV along a diametric beam path through a smoke cloud inside the circle, and a second emitter positioned at a location on the circumference at an arc length 4θ from the first emitter to alternately direct polarized light of wavelength λ′H and λ′V along a diametric beam path, and a third emitter positioned at a location on the circumference at an arc length 4θ from the first emitter, wherein the third emitter is opposite the beam path of the first emitter from the second emitter, and wherein the third emitter alternately directs polarized light of wavelength λ″H and λ″V along a diametric beam path, and further wherein horizontally polarized detectors and vertically polarized detectors are selectively positioned on opposite sides of the beam path at locations of θ, 3θ and 5θ arc lengths from the first emitter;
- individually activating each emitter for a predetermined time interval, in sequence, to simultaneously generate response signals (S) in all detectors of the system;
- computing a polarization ratio, ρ(θ), wherein
- ρ(θ)=σHH(θ)/σVV(θ)
- with σHH(θ) and σVV(θ) respectively being a differential mass scattering cross section for horizontally polarized light and for vertically polarized light;
- and
- using the polarization ratio, ρ(θ), to identify smoke from a petrochemical (hydrocarbon) source.
4 more elements
Dependencies are inferred from the claim text.