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US3569825A
Expired / Lapsed
US
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Corona discharge plasma oscillation gas trace detector
Assignee: GCA Corp
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Filing: 1969-02-06
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Granted: 1971-03-09
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Expires: 1989-02-06
Abstract
Abstract A method and apparatus for sensing and measuring the presence and amount of a specific gaseous component in a volume of gas as well as measuring gas density over a range of densities. The gas under teat is subjected to an inhomogeneous electric field to create a plasma having characteristic oscillation frequencies. By comparison with previously charted data or by comparison with the output of a simultaneously excited reference gas, the presence and concentration of the specific component may be evidenced by the plasma oscillation frequencies.
Inventors
- 👤 Pedro Lilienfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:15
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/62
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
55 words
A method of analyzing a test gas comprising the steps of: sampling said test gas; creating a first inhomogeneous electric field in said test gas; increasing the strength of said electric field to produce coherent plasma oscillations; and measuring the frequency of said coherent plasma oscillations to provide a data characteristic of said test gas.
Claim 2
Independent Claim
55 words
A method of analyzing a test gas comprising the steps of: sampling said test gas; creating a first inhomogeneous electric field in said test gas; increasing the strength of said electric field to produce coherent plasma oscillations; and measuring the frequency of said coherent plasma oscillations to provide a data characteristic of said test gas.
Claim 3
Dependent Claim
87 words
A method of determining the composition of a test gas as defined in claim 1 further comprising: simultaneously sampling a reference gas of known composition; creating a second inhomogeneous electric field similar to said first electric field in said reference gas; increasing the strength of said second electric field to produce coherent plasma oscillations in said reference gas; and comparing the oscillation frequency of said reference gas with the oscillation frequency of said test gas whereby to provide an indication of the composition of said test gas.
Claim 4
Dependent Claim
59 words
A method as defined in claim 2 wherein the step of comparing the oscillation frequency of said reference gas with that of said test gas includes determining the frequency difference between the oscillation frequency of said reference gas and that of said test gas as a function of the presence and concentration of a component of said test gas.
Claim 5
Dependent Claim
59 words
A method as defined in claim 2 wherein the step of comparing the oscillation frequency of said reference gas with that of said test gas includes determining the frequency ratio between the oscillation frequency of said reference gas and that of said test gas as a function of the presence and concentration of a component of said test gas.
Claim 6
Dependent Claim
45 words
A method as defined in claim 2 wherein the step of sampling said reference gas includes the step of sampling ambient gas and the step of sampling said test gas incluDes the steps of sampling said ambient gas and eliminating a specific gaseous component therefrom.
Claim 7
Dependent Claim
28 words
A method as defined in claim 1 and further including the step of reducing the pressure of said test gas to a predetermined pressure during the sampling thereof.
Claim 8
Dependent Claim
33 words
A method as defined in claim 2 and further including the steps of reducing the pressure of said test gas and of said reference gas to a predetermined pressure during the sampling thereof.
Claim 9
Dependent Claim
57 words
Apparatus for analyzing the composition of a test gas comprising: means for ionizing said test gas to a plasmic state at which coherent plasma oscillations at a frequency characteristic of said test gas are generated; and means for measuring the frequency of said coherent plasma oscillations to provide an indication of the composition of said test gas.
Claim 10
Dependent Claim
57 words
Apparatus for analyzing the composition of a test gas comprising: means for ionizing said test gas to a plasmic state at which coherent plasma oscillations at a frequency characteristic of said test gas are generated; and means for measuring the frequency of said coherent plasma oscillations to provide an indication of the composition of said test gas.
Claim 11
Dependent Claim
47 words
Apparatus as defined in claim 8 wherein said means for ionizing said test gas comprises: means for applying an inhomogeneous electric field to said test gas, at least a portion of said field being of an intensity sufficient to produce said plasmic region and coherent plasma oscillations.
Claim 12
Dependent Claim
79 words
Apparatus as defined in claim 8 and further comprising: means for ionizing a reference gas of known composition under identical conditions as those for ionizing said test gas to produce a reference plasmic region within said reference gas and coherent plasma oscillations at a frequency characteristic of said reference gas; and means for comparing the frequencies of oscillation of said reference gas plasma and said test gas plasma to provide an indication of the composition of said test gas.
Claim 13
Dependent Claim
58 words
Apparatus as defined in claim 10 wherein each of said means for ionizing said gases comprises: a container for one of said gases; an electrode disposed within said container; means for applying a DC potential across said container and said electrode; and means for controlling said applied potential to generate a field of predetermined gradient within said container.
Claim 14
Dependent Claim
22 words
Apparatus as defined in claim 8 and further comprising: means for rarefying said test gas prior to ionizing an said test gas.
Claim 15
Dependent Claim
114 words
Apparatus as defined in claim 10 wherein said means for ionizing said reference gas and said test gas comprises: a pair of containers, each of said containers having an inlet end and an outlet end; means for inducting said reference gas into one of said containers; means for inducting said test gas into the other of said containers; an electrode disposed within each of said containers; a source of DC potential; means for applying said DC potential across each of said containers and its associated electrode to produce said plasmic regions and coherent plasma oscillations; and means for comparing the plasma oscillation frequencies of said reference gas and said test gas in said containers.
Claim 16
Dependent Claim
22 words
Apparatus as defined in claim 13 and further comprising: means connected to said containers for rarefying said gases to a predetermined pressure.
Claim 17
Independent Claim
72 words
A method of ann analyzing the composition of a gas comprising: subjecting said gas to an electric discharge gap defined by a pair of electrodes; applying a nonuniform electric field across said discharge gap, said field being of a gradient such that the region about one of said electrodes is highly stressed to a degree wherein coherent plasma oscillations, characteristic of said gas, are generated; and measuring the frequency of said oscillations.
Claim 18
Independent Claim
72 words
A method of ann analyzing the composition of a gas comprising: subjecting said gas to an electric discharge gap defined by a pair of electrodes; applying a nonuniform electric field across said discharge gap, said field being of a gradient such that the region about one of said electrodes is highly stressed to a degree wherein coherent plasma oscillations, characteristic of said gas, are generated; and measuring the frequency of said oscillations.
Claim 19
Dependent Claim
88 words
Apparatus for analyzing the composition of a gas comprising: a pair of electrodes arranged to define an electric discharge gap therebetween; means for applying a nonuniform electric field across said discharge gap, thereby to subject said gas to said electric field when said gas occupies said discharge gap, said field being of a gradient such that the region about one of said electrodes is highly stressed to a degree wherein coherent plasma oscillations, characteristic of said gaS, are generated; and means for measuring the frequency of said oscillations.
Claim 20
Dependent Claim
88 words
Apparatus for analyzing the composition of a gas comprising: a pair of electrodes arranged to define an electric discharge gap therebetween; means for applying a nonuniform electric field across said discharge gap, thereby to subject said gas to said electric field when said gas occupies said discharge gap, said field being of a gradient such that the region about one of said electrodes is highly stressed to a degree wherein coherent plasma oscillations, characteristic of said gaS, are generated; and means for measuring the frequency of said oscillations.
References Cited (Backward Citations)
US3484602A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |