US3796499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for determining the concentration of paramagnetic material in a gas mixture
Assignee: RTX Corp
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Filing: 1973-03-22
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Granted: 1974-03-12
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Expires: 1993-03-22
Abstract
Abstract A method and system for detecting the presence of a paramagnetic material in a gaseous mixture are disclosed. A sample of the mixture is subjected to modest strength magnetic fields and a source of stable frequency laser radiation. The magnetic field modifies an energy level spacing in the paramagnetic material due to the Zeeman effect to produce a resonant match with the laser radiation. Standard detection procedures are used to quantitatively correlate the variation in the intensity of the laser radiation passing through the mixture as a function of the magnetic field strength. In the case of nitric oxide, the method is sufficiently sensitive to detect concentrations considerably less than one part per million.
Inventors
- 👤 P Bonczyk
- 👤 C Ultee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:09
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/72; G01N27/74; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/39; G01N24/00; G01N24/006
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
129 words
Apparatus for determining the concentration of a paramagnetic material in a gaseous mixture comprising: means providing a beam of stable frequency laser radiation along an optical path; enclosure means for containing the gaseous mixture which is positioned in the optical path; means providing a primary magnetic field within the enclosure means with a source of direct electric current, the primary magnetic field being disposed about a central axis which penetrates the enclosure means and is colinear with the optical path; means for sweeping the intensity of the primary magnetic field in the enclosure means; means providing a secondary magnetic field within the enclosure means with a source of alternating electric current; and means for sensing the intensity variation of the laser radiation which is transmitteD through the enclosure means.
Claim 2
Dependent Claim
129 words
Apparatus for determining the concentration of a paramagnetic material in a gaseous mixture comprising: means providing a beam of stable frequency laser radiation along an optical path; enclosure means for containing the gaseous mixture which is positioned in the optical path; means providing a primary magnetic field within the enclosure means with a source of direct electric current, the primary magnetic field being disposed about a central axis which penetrates the enclosure means and is colinear with the optical path; means for sweeping the intensity of the primary magnetic field in the enclosure means; means providing a secondary magnetic field within the enclosure means with a source of alternating electric current; and means for sensing the intensity variation of the laser radiation which is transmitteD through the enclosure means.
Claim 3
Dependent Claim
34 words
Apparatus according to claim 1 including recording means for graphically describing the intensity of the transmitted laser radiation as a function of the intensity of the primary magnetic field maintained within the enclosure means.
Claim 4
Dependent Claim
24 words
Apparatus according to claim 1 wherein the means providing a beam of stable frequency laser radiation comprises an electric discharge excited carbon monoxide laser.
Claim 5
Dependent Claim
27 words
Apparatus according to claim 1 wherein the enclosure means for containing the gaseous mixture comprises a nonmagnetic container having windows which are transparent to the laser radiation.
Claim 6
Dependent Claim
36 words
Apparatus according to claim 1 wherein the means for sweeping the primary magnetic field comprises a constant voltage power supply having a regulated stable current output which is programmed to provide a linearly changing magnetic field.
Claim 7
Dependent Claim
35 words
Apparatus according to claim 1 wherein the means for determining the intensity of the laser radiation which is transmitted through the enclosure means comprises an infrared detector, a frequency selective preamplifier and a lock-in amplifier.
Claim 8
Dependent Claim
13 words
Apparatus according to claim 2 wherein the recording means comprises an x-y recorder.
Claim 9
Independent Claim
121 words
The method of determining the concentration of nitric oxide in a gaseous mixture with laser radiation having an energy of 3.507 microns including the steps of: providing a stable frequency beam of the laser radiation; directing the beam of laser radiation through an enclosure which is filled with the gaseous mixture; applying a direct current magnetic field to the nitric oxide to tune its absorptivity to the wavelength of the laser radiation by the Zeeman effect; determining the intensity variation of the laser radiation which is transmitted through the enclosure; and comparing the intensity of the radiation transmitted through the enclosure with the intensity variation in the laser radiation passed through a calibrated sample containing a known quantity of nitric oxide.
Claim 10
Independent Claim
121 words
The method of determining the concentration of nitric oxide in a gaseous mixture with laser radiation having an energy of 3.507 microns including the steps of: providing a stable frequency beam of the laser radiation; directing the beam of laser radiation through an enclosure which is filled with the gaseous mixture; applying a direct current magnetic field to the nitric oxide to tune its absorptivity to the wavelength of the laser radiation by the Zeeman effect; determining the intensity variation of the laser radiation which is transmitted through the enclosure; and comparing the intensity of the radiation transmitted through the enclosure with the intensity variation in the laser radiation passed through a calibrated sample containing a known quantity of nitric oxide.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |