EP0476601A1
Expired / Lapsed
EP
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Burner flame sensing system and method
Assignee: Fireye Inc
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Filing: 1991-09-18
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Granted: —
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Expires: 2011-09-18
Abstract
Abstract The presence of a flame from a burner is determined by analyzing the signal produced by a radiation sensor (12) aimed at a burner. The signal produced by the radiation sensor (12) is applied to the analog input of a microcomputer (50) and processed therein. Specifically, a Fourier transformation is applied to the signal producing amplitude values for a spectrum of component frequencies produced by changes in the power of the flame over time. A logarithmic value is derived for each of the amplitude values. The degree of linearity of the distribution of the component frequency logarithmic amplitude values provides an indication of the flame presence. Several parameters, including integrated linear error, linearity regression correlation and slope difference, provide an indication of the degree of linearity. A plurality of values for each of these parameters are produced during an interval of time. When a given percentage of the parameter values are above their respective thresholds the flame is determined to be present, whereas when another given percentage of the parameter values are below their respective threshold the flame is determined to be extinguished.
Inventors
- 👤 Kenneth C. Cormier
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:13
CPC Classifications
F; F23; F23N; F23N5/00; F23N5/02; F23N5/08; F23N5/082; F23N2223/00; F23N2223/08; F23N2223/10; F23N2229/00; F23N2229/08; F23N2229/22
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
72 words
A flame analyzer comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; means for transforming the electrical signal into a spectrum of component frequencies of the electrical signal which component frequencies are due to power changes of the flame with time; and means for determining a characteristic of the flame in response to the spectrum of component frequencies of the electrical signal.
Claim 2
Dependent Claim
72 words
A flame analyzer comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; means for transforming the electrical signal into a spectrum of component frequencies of the electrical signal which component frequencies are due to power changes of the flame with time; and means for determining a characteristic of the flame in response to the spectrum of component frequencies of the electrical signal.
Claim 3
Dependent Claim
27 words
The flame analyzer as recited in claim 1 wherein said means for transforming the electrical signal comprises means for performing a Fourier transformation on the electrical signal.
Claim 4
Dependent Claim
95 words
A flame analyzer comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; means for converting the electrical signal into a spectrum comprising a plurality of component frequencies of the electrical signal, the component frequencies resulting from changes in power of the flame with time, and wherein each component frequency has an amplitude; means for determining a degree of linearity of a distribution of component frequency amplitudes throughout the spectrum; and means for determining a characteristic of the flame in response to the degree of linearity.
Claim 5
Dependent Claim
95 words
A flame analyzer comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; means for converting the electrical signal into a spectrum comprising a plurality of component frequencies of the electrical signal, the component frequencies resulting from changes in power of the flame with time, and wherein each component frequency has an amplitude; means for determining a degree of linearity of a distribution of component frequency amplitudes throughout the spectrum; and means for determining a characteristic of the flame in response to the degree of linearity.
Claim 6
Dependent Claim
27 words
The flame analyzer as recited in claim 3 wherein said means for converting the electrical signal comprises means for performing a Fourier transformation on the electrical signal.
Claim 7
Dependent Claim
40 words
The flame analyzer as recited in claim 3 wherein said means for determining a degree of linearity comprises means for determining a difference between slopes of the distribution of component frequency amplitudes at at least two frequencies of the spectrum.
Claim 8
Dependent Claim
59 words
The flame analyzer as recited in claim 3 wherein said means for determining a degree of linearity comprises means for determining a linearity regression correlation (R) for the distribution of component frequency amplitudes as given by the expression: where i is the number of component frequencies and s ; is the amplitude of a component frequency f ; .
Claim 9
Dependent Claim
91 words
The flame analyzer as recited in claim 3 wherein said means for determining a degree of linearity comprises: means for deriving data values for a set of the component frequencies, each data value being defined by an equation of a line tangent at a given point to the distribution of component frequency amplitudes; and means for integrating the difference between the amplitude produced by said means for converting and the data value for each member of the set of component frequencies to produce a first value indicative of the degree linearity.
Claim 10
Dependent Claim
81 words
The flame analyzer as recited in claim 7 wherein said means for determining a degree of linearity further comprises: means for determining a difference between slopes of the distribution of component frequency amplitudes at two locations, wherein the difference is a second value indicative of the linearity of the spectrum; and means for determining a linearity regression correlation for the distribution of component frequency amplitudes wherein the linearity regression correlation is a third value indicative of the linearity of the spectrum.
Claim 11
Dependent Claim
187 words
The flame analyzer as recited in claim 8 wherein said means for determining a characteristic of the flame comprises: a first means for comparing a plurality of the first values to a first threshold to determine amounts of the first values that are respectively above and below the first threshold; a second means for comparing a plurality of the second values to a second threshold to determine amounts that are respectively above and below the second threshold; a third means for comparing a plurality of the third values to a third threshold to determine amounts that are respectively above and below the third threshold; first means for averaging the amounts of the first, second and third values below their respective thresholds to produce a first average; second means for averaging the amounts of the first, second and third values above their respective thresholds to produce a second average; and means for producing an indication that the flame is extinguished when the first average exceeds a first reference value, and for producing and indication that the flame is present when the second average exceeds a second reference value.
Claim 12
Independent Claim
129 words
An apparatus for detecting the presence of a flame comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; an automatic gain controlled amplifier for amplifying the electrical signal; means for digitizing the electrical signal from said amplifier into a plurality of signal samples; means for storing the plurality of signal samples; means for transforming the signal samples from a time domain to a frequency domain to produce a plurality of component frequency amplitude values; means for deriving a logarithmic value for each component frequency amplitude value of the electrical signal; means for determining a degree of linearity of a distribution of the logarithmic values; and means for evaluating the degree of linearity to determine whether the flame is present.
Claim 13
Independent Claim
129 words
An apparatus for detecting the presence of a flame comprising: a sensor for detecting radiation produced by a flame and producing an electrical signal indicative of the radiation; an automatic gain controlled amplifier for amplifying the electrical signal; means for digitizing the electrical signal from said amplifier into a plurality of signal samples; means for storing the plurality of signal samples; means for transforming the signal samples from a time domain to a frequency domain to produce a plurality of component frequency amplitude values; means for deriving a logarithmic value for each component frequency amplitude value of the electrical signal; means for determining a degree of linearity of a distribution of the logarithmic values; and means for evaluating the degree of linearity to determine whether the flame is present.
Claim 14
Dependent Claim
32 words
The flame analyzer as recited in claim 10 wherein said means for determining a degree of linearity determines a difference between slopes at two locations along the distribution of the logarithmic values.
Claim 15
Dependent Claim
29 words
The flame analyzer as recited in claim 10 wherein said means for determining a degree of linearity determines a linearity regression correlation for the distribution of the logarithmic values.
Claim 16
Dependent Claim
65 words
The flame analyzer as recited in claim 10 wherein said means for determining a degree of linearity comprises: means for defining a line tangent to a given point along the distribution of logarithmic values; and means for integrating a series of differences between the logarithmic values and points on the defined line thereby producing a first value indicative of the linearity of the logarithmic values.
Claim 17
Dependent Claim
70 words
The flame analyzer as recited in claim 13 wherein said means for determining a degree of linearity further comprises: means for determining a difference between slopes at two locations on the distribution of logarithmic values to produce a second value indicative of the degree linearity; and means for determining a linearity regression correlation for the distribution of logarithmic values to produce a third value indicative of the degree of linearity.
Claim 18
Dependent Claim
214 words
The flame analyzer as recited in claim 14 wherein means for evaluating the degree of linearity comprises: a first means for comparing a plurality of the first values to a first threshold to determine an amount of the first values below the first threshold and an amount of the first values above the first threshold; a second means for comparing a plurality of the second values to a second threshold to determine an amount of the second values below the second threshold and an amount of the second values above the second threshold; a third means for comparing a plurality of the third values to a third threshold to determine an amount of the third values below the third threshold and an amount of the third values above the third threshold; first means for averaging the amounts of the first, second and third values below their respective thresholds to produce a first average; second means for averaging the amounts of the first, second and third values above their respective thresholds to produce a second average; and means for producing an indication that the flame is extinguished when the first average exceeds a first reference value, and for producing and indication that the flame is present when the second average exceeds a second reference value.
Claim 19
Independent Claim
83 words
A method for determining a characteristic of a flame comprising: detecting radiation at a frequency produced by a flame and producing an electrical signal indicative of the radiation; transforming the electrical signal from a time domain to a frequency domain to produce amplitude values for a plurality of component frequencies which result from shape changes of the flame with time; determining a degree of linearity of a distribution of the amplitude values; and employing the degree of linearity to determine a flame characteristic.
Claim 20
Independent Claim
83 words
A method for determining a characteristic of a flame comprising: detecting radiation at a frequency produced by a flame and producing an electrical signal indicative of the radiation; transforming the electrical signal from a time domain to a frequency domain to produce amplitude values for a plurality of component frequencies which result from shape changes of the flame with time; determining a degree of linearity of a distribution of the amplitude values; and employing the degree of linearity to determine a flame characteristic.
Claim 21
Dependent Claim
24 words
The method as recited in claim 16 wherein said step of transforming the electrical signal comprises performing a Fourier transformation of the electrical signal.
Claim 22
Dependent Claim
38 words
The method as recited in claim 16 wherein said step of determining a degree of linearity comprises deriving a logarithmic value for each amplitude value; and determining a degree of linearity of a distribution of the logarithmic values.
Claim 23
Dependent Claim
32 words
The method as recited in claim 16 wherein said step of determining a degree of linearity comprises deriving a difference between slopes at two points on the distribution of the amplitude values.
Claim 24
Dependent Claim
31 words
The method as recited in claim 16 wherein said step of determining a degree of linearity comprises means for determining a linearity regression correlation for the distribution of the amplitude values.
Claim 25
Dependent Claim
74 words
The method as recited in claim 16 wherein said step of determining a degree of linearity comprises: deriving data values for the component frequencies from an equation of a line tangent at a given point to the distribution of the amplitude values; and integrating the differences between an amplitude value and a data value for each component frequency in a given frequency band to produce a first value indicative of the degree of linearity.
Claim 26
Dependent Claim
66 words
The method as recited in claim 21 wherein said step of determining a degree of linearity comprises: determining a difference between slopes at two points on the distribution of amplitude values to produce a second value indicative of the degree of linearity; and determining a linearity regression correlation for the distribution of the amplitude values to produce a third value indicative of the degree of linearity.
Claim 27
Dependent Claim
224 words
The method as recited in claim 22 wherein said step of determining a degree of linearity further comprises: comparing a plurality of the first values to a first threshold to determine an amount of the first values that are below the first threshold and an amount of the first values that are above the first threshold; comparing a plurality of the second values to a second threshold to determine an amount of the second values that are below the second threshold and an amount of the second values that are above the second threshold; comparing a plurality of the third values to a third threshold to determine an amount of the third values that are below the third threshold and an amount of the third values that are above the third threshold; averaging the amounts of the first, second and third values that are below their respective thresholds to produce a first average; averaging the amounts of the first, second and third values that are above their respective thresholds to produce a second average; and wherein said step of employing the degree of linearity to determine a flame characteristic produces an indication that the flame is extinguished when the first average exceeds a first reference value, and produces and indication that the flame is present when the second average exceeds a second reference value.
References Cited (Backward Citations)
DE1960218A1
Cited
US4709155A
Cited
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