US4457162A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multi-frequency photo-acoustic detector
Assignee: Gas Technology Institute
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Filing: 1982-09-17
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Granted: 1984-07-03
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Expires: 2002-09-17
Abstract
Abstract An apparatus and process for detecting a single specific chemical solid or gas in the presence of other chemical solids or gases or for detecting a number of specific mixed chemical solids or gases. The apparatus and process passes multiple beams of electromagnetic radiation incident on the material in a sample chamber producing acoustic signals at specific frequencies when light of specific wavelengths is absorbed. The electromagnetic radiation is selected to have wavelengths corresponding to optical absorption features of at least one specific chemical in the sample chamber. The acoustic signals are detected by at least one beat tone or combination tone characteristic of and representative of the degree of absorption by a specific chemical or multiple specific chemicals desired to be detected. The apparatus and process are especially useful in leak detection in natural gas systems and for detection of pollutants, explosive gases and the like.
Inventors
- 👤 William F. Rush
- 👤 James E. Huebler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:48
CPC Classifications
G; G01; G01M; G01M3/00; G01M3/38; G01M3/02; G01M3/04; G01M3/24; G01M3/243; G01N; G01N21/00; G01N21/17; G01N21/1702; G01N2021/1704; G01N2021/1706
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
123 words
A process for detecting a single specific gas or solid in a mixture or a number of specific mixed gases or solid materials comprising: passing said material to be detected into a sample chamber; modulating multiple beams of electromagnetic radiation having wavelengths corresponding to a characteristic absorbed wavelength of at least one of the chemicals in said material to be detected; simultaneously passing multiple beams of said modulated electromagnetic radiation incident on said material to be detected in said sample chamber causing multiple acoustical signals at specific frequencies upon absorption of said modulated beams of electromagnetic radiation; and detecting the acoustical signal corresponding to at least one beat tone or at least one combination tone characteristic of said specific material to be detected.
Claim 2
Dependent Claim
123 words
A process for detecting a single specific gas or solid in a mixture or a number of specific mixed gases or solid materials comprising: passing said material to be detected into a sample chamber; modulating multiple beams of electromagnetic radiation having wavelengths corresponding to a characteristic absorbed wavelength of at least one of the chemicals in said material to be detected; simultaneously passing multiple beams of said modulated electromagnetic radiation incident on said material to be detected in said sample chamber causing multiple acoustical signals at specific frequencies upon absorption of said modulated beams of electromagnetic radiation; and detecting the acoustical signal corresponding to at least one beat tone or at least one combination tone characteristic of said specific material to be detected.
Claim 3
Dependent Claim
15 words
The process of claim 1 wherein 2 to 6 beams of electromagnetic radiation are used.
Claim 4
Dependent Claim
15 words
The process of claim 1 wherein 2 to 4 beams of electromagnetic radiation are used.
Claim 5
Dependent Claim
13 words
The process of claim 1 wherein said material to be detected is gaseous.
Claim 6
Dependent Claim
13 words
The process of claim 1 wherein said material to be detected is solid.
Claim 7
Dependent Claim
25 words
The process of claim 1 wherein said wavelengths of electromagnetic radiation correspond to multiple characteristic absorbed wavelengths of a single chemical material to be detected.
Claim 8
Dependent Claim
26 words
The process of claim 1 wherein each of said wavelengths of electromagnetic radiation corresponds to single characteristic absorbed wavelengths of different chemical materials to be detected.
Claim 9
Dependent Claim
17 words
The process of claim 1 wherein said electromagnetic radiation is modulated by passing through a mechanical chopper.
Claim 10
Dependent Claim
15 words
The process of claim 1 wherein said electromagnetic radiation is modulated by the originating source.
Claim 11
Dependent Claim
21 words
The process of claim 1 wherein said beams of electromagnetic radiation are produced by light sources emitting a narrow wavelength beam.
Claim 12
Dependent Claim
19 words
The process of claim 1 wherein said acoustical signal is passed through a non-linear electronic element prior to detection.
Claim 13
Dependent Claim
13 words
The process of claim 1 wherein at least one beat tone is detected.
Claim 14
Dependent Claim
13 words
The process of claim 1 wherein at least one combination tone is detected.
Claim 15
Dependent Claim
37 words
The process of claim 1 wherein said material to be detected is gaseous; two to four beams of said electromagnetic radiation are used; and said acoustical signal is passed through a non-linear electronic element prior to detection.
Claim 16
Dependent Claim
13 words
The process of claim 14 wherein at least one beat tone is detected.
Claim 17
Dependent Claim
13 words
The process of claim 14 wherein at least one combination tone is detected.
Claim 18
Independent Claim
140 words
An apparatus for detecting a single specific gas or solid material in a mixture or a number of specific mixed gases or solid materials comprising: means defining a sample chamber for containing said material; means for generating at least one beam of electromagnetic radiation; means for simultaneously passing incident on said material in said sample chamber multiple beams of modulated electromagnetic radiation at wavelengths corresponding to a characteristic absorbed wavelength of at least one of the chemicals in said material to be detected; means for acoustical detection of multiple acoustical signals at specific frequencies upon absorption of said modulated beams of electromagnetic radiation providing an output electrical signal corresponding to a beat tone or a combination tone characteristic of said specific material or said number of specific mixed materials; and means for detection and indication of said output electrical signal.
Claim 19
Independent Claim
140 words
An apparatus for detecting a single specific gas or solid material in a mixture or a number of specific mixed gases or solid materials comprising: means defining a sample chamber for containing said material; means for generating at least one beam of electromagnetic radiation; means for simultaneously passing incident on said material in said sample chamber multiple beams of modulated electromagnetic radiation at wavelengths corresponding to a characteristic absorbed wavelength of at least one of the chemicals in said material to be detected; means for acoustical detection of multiple acoustical signals at specific frequencies upon absorption of said modulated beams of electromagnetic radiation providing an output electrical signal corresponding to a beat tone or a combination tone characteristic of said specific material or said number of specific mixed materials; and means for detection and indication of said output electrical signal.
Claim 20
Dependent Claim
16 words
The apparatus of claim 17 wherein said means for generating electromagnetic radiation comprises a laser source.
Claim 21
Dependent Claim
16 words
The apparatus of claim 17 wherein said means for generating electromagnetic radiation comprises an incandescent source.
Claim 22
Dependent Claim
16 words
The apparatus of claim 17 wherein said means for generating electromagnetic radiation comprises an arc source.
Claim 23
Dependent Claim
16 words
The apparatus of claim 17 wherein said means for generating electromagnetic radiation comprises an infrared source.
Claim 24
Dependent Claim
15 words
The apparatus of claim 17 additionally comprising a mechanical chopper for modulating said electromagnetic radiation.
Claim 25
Dependent Claim
18 words
The apparatus of claim 17 additionally comprising light beam interference filters for isolation of desired wavelength electromagnetic radiation.
Claim 26
Dependent Claim
15 words
The apparatus of claim 17 comprising a microphone in said sample chamber for acoustical detection.
Claim 27
Dependent Claim
22 words
The apparatus of claim 17 wherein said means for detection of said output electrical signal comprises at least one non-linear electronic element.
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) | 1987-07-03 | 1988-01-02 | 1988-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-07-03 | 1992-01-02 | 1992-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-07-03 | 1996-01-02 | 1996-07-03 | $7700.00 | Window Closed / Lapsed |