US3612686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for gas analysis utilizing a direct current discharge
Assignee: IIT Research Institute
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Filing: 1968-01-03
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Granted: 1971-10-12
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Expires: 1988-01-03
Abstract
Abstract A method and apparatus for spectrochemical analysis of a gas is provided in which the subject gas is mixed with a carrier gas and introduced into an analysis space between two electrodes. A continuous direct current discharge between the electrodes is produced which sustains a plasma formed from the carrier gas so that components of the subject gas are excited to luminescence. Characteristic radiation emitted by the components is then detected. The carrier gas has a higher ionization potential than components of the subject gas and, for example, may be a noble gas. The method is operable at atmospheric pressure. The electrodes may be either solid wires or tubes through which the gas mixture enters and leaves the analysis space.
Inventors
- 👤 Robert A Braman
- 👤 Alexander Dynako
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:55
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/66; G01N21/69
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
29 words
A method of analyzing a subject gas in accordance with claim 1 wherein said step of mixing said subject gas comprises mixing said subject gas with a noble gas.
Claim 2
Dependent Claim
27 words
A method of analyzing a subject gas in accordance with claim 1 wherein said step of mixing said subject gas comprises mixing said subject gas with helium.
Claim 3
Dependent Claim
38 words
A method of analyzing a subject gas in accordance with claim 1 including causing said gas mixture to flow into said analysis space at one end thereof and out of said analysis space at the other end thereof.
Claim 4
Dependent Claim
32 words
A method of analyzing a subject gas in accordance with claim 4 including introducing said gas mixture into said analysis space at a rate of less than about 300 milliliters per minute.
Claim 5
Dependent Claim
39 words
A method of analyzing a subject gas in accordance with claim 1 including applying a direct current voltage of the order of 1, 000 volts to produce a continuous direct current discharge of the order of about 20 milliamps.
Claim 6
Dependent Claim
172 words
Apparatus for analyzing a subject gas comprising means for mixing said subject gas with a carrier gas having a higher ionization potential than any of the components of said subject gas to provide a gas mixture, a gas analysis chamber at substantially atmospheric pressure for receiving said gas mixture, two electrodes positioned within said chamber adjacent opposite ends thereof and defining an elongated analysis space within said chamber, power means for applying a direct current voltage to said electrodes of such magnitude as to produce a small continuous direct current discharge between said elecTrodes and to produce in said analysis space and sustain the existence therein of a plasma formed from said carrier gas whereby components of said subject gas are excited to emit light by transfer of energy from said plasma, means for resolving said emitted light into a spectrum, and means for selectively detecting the existence and intensity of various frequencies of said light to indicate the amount of corresponding components of said subject gas in said gas analysis space.
Claim 7
Dependent Claim
52 words
Apparatus in accordance with claim 7 wherein said gas analysis chamber includes a gas inlet for said gas mixture adjacent one of said electrodes and a gas outlet for said gas mixture adjacent the other of said electrodes so that said gas mixture flows through said chamber longitudinally of said analysis space.
Claim 8
Dependent Claim
16 words
Apparatus in accordance with claim 7 wherein each of said electrodes comprise a solid thin wire.
Claim 9
Dependent Claim
46 words
Apparatus in accordance with claim 7 wherein each of said electrodes comprises a hollow conductive tube in contact with said gas along its length through one of which tubes said gas enters said chamber and through the other of which tubes said gas leaves said chamber.
Claim 10
Dependent Claim
34 words
Apparatus in accordance with claim 7 wherein said gas analysis space has a length of between about one-fourth inch and about three-fourths inch and a diameter of between about 1 mm. and 10 mm.
Claim 11
Dependent Claim
25 words
Apparatus in accordance with claim 11 wherein said power means supplies a power of about 10 to 40 watts per inch of analysis space length.
Claim 12
Dependent Claim
16 words
Apparatus in accordance with claim 7 wherein said chamber is formed of heat resistant translucent glass.
Claim 13
Dependent Claim
15 words
Apparatus in a accordance with claim 7 wherein said chamber is formed of translucent quartz.
Claim 14
Dependent Claim
164 words
Apparatus for use in analyzing a subject gas mixed with a carrier gas having a higher ionization potential than any of the components of said subject gas comprising a gas analysis chamber at substantially atmospheric pressure for receiving said gas mixture, two electrodes positioned within said chamber adjacent opposite ends thereof and defining an elongated analysis space within said chamber, power means for applying a direct current voltage to said electrodes of such magnitude as to produce a small continuous direct current discharge between said electrodes and to produce in said analysis space and sustain the existence therein of a plasma formed from said carrier gas whereby components of said subject gas are excited to emit light by transfer of energy from said plasma, means for resolving said emitted light into a spectrum, and means for selectively detecting the existence and intensity of various frequencies of said light to indicate the amount of corresponding components of said subject gas in said gas analysis space.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-11 | 1975-04-12 | 1975-10-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-11 | 1979-04-12 | 1979-10-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-11 | 1983-04-12 | 1983-10-12 | $7700.00 | Window Closed / Lapsed |