US4057349A
Expired / Lapsed
US
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Spectroscopic temperature measurement
Assignee: Honeywell International Inc
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Filing: 1976-08-31
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Granted: 1977-11-08
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Expires: 1996-08-31
Abstract
Abstract A method and apparatus for determining the temperature of gaseous materials are provided. Light produced by scattering in a gaseous material and having spectral components periodic in frequency is collected, collimated and transmitted by a light conditioning means to an interferometric means. The interferometric means selectively separates periodic spectra from the light and transmits the spectra in the form of a detectable signal containing first and second branches of the spectra. Means are provided for measuring the intensities of the branches and detecting and recovering the intensity ratio thereof, which is correlated with the temperature of the gaseous material.
Inventors
- 👤 Joseph J. Barrett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:33
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/60; G01J5/601; G01J5/0014
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
214 words
Apparatus for determining the temperature of a gaseous material by analyzing light having spectral components periodic in frequency, comprising: a. light conditioning means for collecting, collimating and transmitting said light; b. interferometric means adapted to receive said light for selectively separating periodic spectra therefrom and transmitting said spectra in the form of a detectable signal, said interferometric means having interference-producing means for providing a plurality of transmission windows regularly spaced in frequency, the frequency spacing between adjacent windows being adjusted to depart from an odd integral submultiple, n, of the frequency difference between adjacent spectral components of the periodic spectrum of said gaseous material, said odd integral submultiple being at least three so as to produce a split-fringe containing first and second branches of the components, and scanning means for causing the transmission peaks for adjacent nth orders to substantially coincide with the spectral lines of either branch of the components, whereby each branch of said split-fringe is derived from a plurality of periodic spectral lines and has an integrated intensity substantially equal to their sum; c. signal conditioning means for measuring the intensity of each of said branches; and d. detecting means for indicating and recording the intensity ratio of the branches, said intensity ratio correlating with the temperature of said gaseous material.
Claim 2
Dependent Claim
214 words
Apparatus for determining the temperature of a gaseous material by analyzing light having spectral components periodic in frequency, comprising: a. light conditioning means for collecting, collimating and transmitting said light; b. interferometric means adapted to receive said light for selectively separating periodic spectra therefrom and transmitting said spectra in the form of a detectable signal, said interferometric means having interference-producing means for providing a plurality of transmission windows regularly spaced in frequency, the frequency spacing between adjacent windows being adjusted to depart from an odd integral submultiple, n, of the frequency difference between adjacent spectral components of the periodic spectrum of said gaseous material, said odd integral submultiple being at least three so as to produce a split-fringe containing first and second branches of the components, and scanning means for causing the transmission peaks for adjacent nth orders to substantially coincide with the spectral lines of either branch of the components, whereby each branch of said split-fringe is derived from a plurality of periodic spectral lines and has an integrated intensity substantially equal to their sum; c. signal conditioning means for measuring the intensity of each of said branches; and d. detecting means for indicating and recording the intensity ratio of the branches, said intensity ratio correlating with the temperature of said gaseous material.
Claim 3
Dependent Claim
64 words
Apparatus as recited in claim 1, wherein said signal conditioning means includes modulating means for modulating the phase difference between interfering rays of said light so as to compare the peak intensities of said branches of said split-fringe, said modulating range being no greater than the frequency spacing between adjacent nth orders, and synchronous detection means for detecting the intensity ratio of said split-fringe.
Claim 4
Dependent Claim
30 words
Apparatus as recited in claim 2, wherein said modulating means has a modulating range substantially equal to the frequency difference between peak intensity portions of said branches of said split-fringe.
Claim 5
Dependent Claim
24 words
Apparatus as recited in claim 2, wherein said modulating means is a piezoelectric cylinder and said synchronous detection means is a phase-sensitive detection system.
Claim 6
Dependent Claim
27 words
Apparatus as recited in claim 4, wherein said interferometric means is a solid etalon having temperature control means associated therewith for adjusting the optical path length thereof.
Claim 7
Dependent Claim
111 words
Apparatus as recited in claim 4, including means for applying to said cylinder a voltage having a square wave form, the limits of said voltage being adjusted so that the intensity of said split-fringe alternates between the maximum values of said branches, means for determining for each half-cycle of said voltage the photon count at peak intensity of each branch of said split-fringe to produce first and second signal counts, means for accumulating the signal counts for a preselected period of time over a preselected number of cycles of said square wave, and means for dividing the first signal count by the second signal count to produce a signal count ratio.
Claim 8
Dependent Claim
29 words
Apparatus as recited in claim 6, including means for varying the preselected period of time, and the preselected number of cycles inversely with the branch intensities of said split-fringe.
Claim 9
Dependent Claim
16 words
Apparatus as recited in claim 4, wherein said phase sensitive detection system is a lock-in amplifier.
Claim 10
Dependent Claim
16 words
Apparatus as recited in claim 4, wherein said synchronous detection means is a photon counting system.
Claim 11
Dependent Claim
37 words
Apparatus as recited in claim 1, including light source means for generating monochromatic light, and projecting means for directing said monochromatic light through said gaseous material to produce said scattered light having spectral components periodic in frequency.
Claim 12
Dependent Claim
38 words
Apparatus as recited in claim 10, wherein said light source means is provided with means for projecting light having a line width and frequency stability about equal to or less than the instrumental width of said interferometric means.
Claim 13
Dependent Claim
15 words
Apparatus as recited in claim 10, wherein said light source means is a pulsed laser.
Claim 14
Dependent Claim
59 words
Apparatus as recited in claim 12, wherein said laser is associated with a time gated electronic detection system having (1) means for measuring the time interval required to send a pulse from said laser into said gaseous material and receive a return signal caused by light scattered therein and (2) means for measuring the amplitude of said return signal.
Claim 15
Dependent Claim
14 words
Apparatus as recited in claim 1, wherein said interferometric means is a Fabry-Perot interferometer.
Claim 16
Independent Claim
199 words
A method of determining the temperature of a gaseous material by analyzing light having spectral components periodic in frequency, comprising the steps of: a. collecting, collimating and transmitting said light in the form of a ray path; b. interferometrically separating periodic spectra from said light by directing said light through a plurality of transmission windows regularly spaced in frequency, the frequency spacing between adjacent windows being adjusted to depart from an odd integral submultiple, n, of the frequency difference between adjacent spectrum of said gaseous material said odd integral submultiple being at least three so as to produce a split-fringe containing first and second branches of the components, and scanning said ray path to cause the transmission peaks for adjacent nth orders to substantially coincide with the spectral lines of either branch of the components; c. transmitting a detectable signal composed of said split-fringe, each branch of said split-fringe being derived from a plurality of periodic spectral lines and having an integrated intensity substantially equal to their sum; d. measuring the intensity of each of said branches; and e. detecting and recording the intensity ratio of the branches, said intensity ratio correlating with the temperature of said gaseous material.
Claim 17
Independent Claim
199 words
A method of determining the temperature of a gaseous material by analyzing light having spectral components periodic in frequency, comprising the steps of: a. collecting, collimating and transmitting said light in the form of a ray path; b. interferometrically separating periodic spectra from said light by directing said light through a plurality of transmission windows regularly spaced in frequency, the frequency spacing between adjacent windows being adjusted to depart from an odd integral submultiple, n, of the frequency difference between adjacent spectrum of said gaseous material said odd integral submultiple being at least three so as to produce a split-fringe containing first and second branches of the components, and scanning said ray path to cause the transmission peaks for adjacent nth orders to substantially coincide with the spectral lines of either branch of the components; c. transmitting a detectable signal composed of said split-fringe, each branch of said split-fringe being derived from a plurality of periodic spectral lines and having an integrated intensity substantially equal to their sum; d. measuring the intensity of each of said branches; and e. detecting and recording the intensity ratio of the branches, said intensity ratio correlating with the temperature of said gaseous material.
Claim 18
Dependent Claim
28 words
A method as recited in claim 14, wherein said gaseous material comprises a mixture of gases and said preselected spectra are the spectra of a major constituent thereof.
Claim 19
Dependent Claim
13 words
A method as recited in claim 15, wherein said gaseous material is air.
References Cited (Backward Citations)
US3853404A
Cited
US3909132A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-07 | 1981-05-09 | 1981-11-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-07 | 1985-05-09 | 1985-11-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-07 | 1989-05-09 | 1989-11-08 | $7700.00 | Window Closed / Lapsed |