US4066904A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of measurement of the concentration of a substance contained in a gas and devices for carrying out said method
Assignee: Bpifrance Financement SA
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Filing: 1976-05-06
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Granted: 1978-01-03
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Expires: 1996-05-06
Abstract
Abstract In a method for measuring the concentration of a substance contained in a gas, the gas is irradiated with a radiation having a sufficiently short wavelength to photodissociate the substance. A photometric measurement is then carried out on at least one of the products of photodissociation in order to determine its concentration which is proportional to the concentration of the substance to be measured.
Inventors
- 👤 Jean-Loup Bertaux
- 👤 Jacques Alain Quessette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:10
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/62; G01N21/63; G01N21/631; G01N21/17; G01N21/25; G01N21/31; G01N21/33; G01N21/64; G01N27/00; G01N27/62
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
80 words
A method of measurement of the concentration of a photodissociable substance contained in a gas, wherein: a gas having an unknown content of photodissociable substance is irradiated with a radiation having a sufficiently short wavelength to photodissociate said substance, a photometric measurement is carried out on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of the substance to be measured.
Claim 2
Independent Claim
80 words
A method of measurement of the concentration of a photodissociable substance contained in a gas, wherein: a gas having an unknown content of photodissociable substance is irradiated with a radiation having a sufficiently short wavelength to photodissociate said substance, a photometric measurement is carried out on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of the substance to be measured.
Claim 3
Dependent Claim
26 words
A method according to claim 1, wherein the dissociation products are produced in a non-excited state, and said photometric measurement consists of a measurement of absorption.
Claim 4
Dependent Claim
26 words
A method according to claim 1, wherein the dissociation products are produced in a non-excited state, and said photometric measurement consists of a measurement of fluorescence.
Claim 5
Dependent Claim
25 words
A method according to claim 1, and wherein said substance is water vapor, the dissociation products are the hydrogen atom H and the OH radical.
Claim 6
Dependent Claim
58 words
A method according to claim 1, wherein the radiation with which said gas is irradiated has a sufficiently short wavelength to ensure that at least one of the photodissociation products is created in an excited state, whereupon said photometric measurement consists in measuring the intensity of the light emitted at the time of de-excitation of said excited product.
Claim 7
Dependent Claim
47 words
A method according to claim 5, wherein said substance is water vapor, the dissociation products being the hydrogen atom H and the OH radical, and wherein the wavelength of the radiation employed in the irradiation step is 1216 A corresponding to the Lyman alpha line of hydrogen.
Claim 8
Dependent Claim
21 words
A method according to claim 6, wherein the photometric measurement takes place on the optical resonance of hydrogen at 1216 A.
Claim 9
Independent Claim
97 words
A method of measurement of the concentration of water vapor contained in a gas, wherein: said gas is irradiated with a radiation having a sufficiently short wavelength shorter than 1360 A to dissociate the water vapor into dissociation products consisting of the hydrogen atom H and the OH radical, the latter being accordingly produced at the time of photodissociation in an excited OH* state, and photometric measurement is carried out which consists in measuring the intensity of the radiation emitted within the range of 3000 to 3250 A at the time of de-excitation of the OH* radical.
Claim 10
Independent Claim
97 words
A method of measurement of the concentration of water vapor contained in a gas, wherein: said gas is irradiated with a radiation having a sufficiently short wavelength shorter than 1360 A to dissociate the water vapor into dissociation products consisting of the hydrogen atom H and the OH radical, the latter being accordingly produced at the time of photodissociation in an excited OH* state, and photometric measurement is carried out which consists in measuring the intensity of the radiation emitted within the range of 3000 to 3250 A at the time of de-excitation of the OH* radical.
Claim 11
Independent Claim
109 words
A method of measurement of the concentration of a substance contained in a gas, wherein: a gas having an unknown content of a photodissociable substance is irradiated with a radiation having a sufficiently short wavelength to photodissociate said substance, a photometric measurement is carried out in two different zones of the gas on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of the substance to be measured, and a comparison of the results obtained in respect of the two zones is performed to determine the concentration of said substance.
Claim 12
Independent Claim
109 words
A method of measurement of the concentration of a substance contained in a gas, wherein: a gas having an unknown content of a photodissociable substance is irradiated with a radiation having a sufficiently short wavelength to photodissociate said substance, a photometric measurement is carried out in two different zones of the gas on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of the substance to be measured, and a comparison of the results obtained in respect of the two zones is performed to determine the concentration of said substance.
Claim 13
Independent Claim
75 words
A device for measuring the concentration of a photodissociable substance contained in a gas, which device comprises: a source of radiation which emits a radiation having a wavelength shorter than 1360 A disposed for irradiating a volume of said gas, and photometric measuring means constituted by at least one photodetector having a range of sensitivity which includes the waveband from 3000 A to 3250 A, disposed for detecting emission of said radiation in said gas.
Claim 14
Independent Claim
75 words
A device for measuring the concentration of a photodissociable substance contained in a gas, which device comprises: a source of radiation which emits a radiation having a wavelength shorter than 1360 A disposed for irradiating a volume of said gas, and photometric measuring means constituted by at least one photodetector having a range of sensitivity which includes the waveband from 3000 A to 3250 A, disposed for detecting emission of said radiation in said gas.
Claim 15
Dependent Claim
32 words
A device according to claim 10, wherein said device comprises a single measuring channel constituted by a photodetector mounted on orientable mechanical means for scanning a number of zones of the gas.
Claim 16
Dependent Claim
55 words
A device according to claim 10, wherein said device further comprises a retractable scintillator which is placed in that zone of the gas in which the measurement is carried out and converts the radiation employed in the irradiation process to a radiation having a wavelength which falls within the range of sensitivity of the photodetector.
Claim 17
Dependent Claim
14 words
A device according to claim 12, wherein the retractable scintillator is of sodium salicylate.
Claim 18
Dependent Claim
59 words
A device according to claim 10, wherein said device comprises two measuring channels each constituted by a photodetector having a range of sensitivity which contains the waveband from 3000 to 3250 A, said channels being intended to measure the radiation issuing from two separate zones of the gas which are traversed successively by the radiation emitted by the source.
Claim 19
Dependent Claim
26 words
A device according to claim 14, wherein each channel further comprises a bundle of optical fibers placed between the gas zone under study and the photodetector.
Claim 20
Dependent Claim
31 words
A device according to claim 10 for measuring the concentration of water vapor in a gas, wherein the source emits radiation in which the spectrum contains the wavelength of 1216 A.
Claim 21
Dependent Claim
20 words
A device according to claim 16, wherein said device comprises at least one photodetector which is sensitive at 1216 A.
Claim 22
Independent Claim
62 words
A device for measuring the concentration of a photodissociable substance in a gas, which device comprises: a first source of radiation having a wavelength shorter than 1360 A for irradiating the gas, and photometric measuring means constituted by a second radiation source in which the spectrum contains the wavelength of 1216 A and by a photodetector which is sensitive at 1216 A.
Claim 23
Independent Claim
62 words
A device for measuring the concentration of a photodissociable substance in a gas, which device comprises: a first source of radiation having a wavelength shorter than 1360 A for irradiating the gas, and photometric measuring means constituted by a second radiation source in which the spectrum contains the wavelength of 1216 A and by a photodetector which is sensitive at 1216 A.
Claim 24
Independent Claim
105 words
A method of measuring the concentration of contaminants in the atmosphere, wherein: a volume of atmospheric air is irradiated with a radiation having a sufficient short wavelength to photodissociate contaminants, a photometric measurement is carried out in two different zones of the irradiated air on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of a contaminant of which it is a photodissociation product, and a comparison of the results obtained in respect of the two zones is performed to determine the concentration of said contaminant.
Claim 25
Independent Claim
105 words
A method of measuring the concentration of contaminants in the atmosphere, wherein: a volume of atmospheric air is irradiated with a radiation having a sufficient short wavelength to photodissociate contaminants, a photometric measurement is carried out in two different zones of the irradiated air on at least one of the photodissociation products in order to determine its concentration under conditions under which the concentration of the photodissociation product is proportional to the concentration of a contaminant of which it is a photodissociation product, and a comparison of the results obtained in respect of the two zones is performed to determine the concentration of said contaminant.
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) | 1981-01-02 | 1981-07-04 | 1982-01-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-02 | 1985-07-04 | 1986-01-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-02 | 1989-07-04 | 1990-01-03 | $7700.00 | Window Closed / Lapsed |