US3761724A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Double beam hydrocarbon gas detector
Assignee: Resalab Inc
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Filing: 1972-07-06
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Granted: 1973-09-25
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Expires: 1992-07-06
Abstract
Abstract Hydrocarbon gas in a sample is measured by a double beam detector responding to the transmission of absorption properties of the gas in response to applied radiation from a laser source. Monochromatic light from the laser source is split into two radiation beams, a sample path beam and a reference path beam, and directed to a radiation detector which sequentially responds to the reference energy and the sample energy. A difference in the absorption by the sample path energy with respect to the reference path energy produces two, different level, output signals from the detector. The sample energy signal and reference energy signal are respectively directed to a sample channel circuit and a reference channel circuit. Outputs from the individual circuits are amplified logarithmically and applied to inputs of a differential amplifier wherein the ratio of the sample signal to the reference signal produces a voltage for actuating a meter indicator. For a hydrocarbon gas content in a sample in excess of a predetermined limit, an alarm circuit actuates to give an audible warning of an excessive gas content.
Inventors
- 👤 J Dennis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:01
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01N21/27
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
209 words
A hydrocarbon gas detector having a monochromatic light source emitting radiation in the region absorbent of hydrocarbon molecules, said beam split into a sample path beam and a reference path beam both directed through a sample chamber along separate paths to a detector means having an output related to the energy in the sample path and reference path, the improvement comprising: a sample channel circuit responsive to the output signal of the detector means related to the sample path, energy for generating a sample channel output, a reference channel circuit responsive to the output signal of the detector means related to the reference path energy for generating a reference channel output, a logarithmic amplifier connected to the output of the sample channel circuit and the reference channel circuit and generating two outputs, one varying as the logarithm of the sample channel output and the second varying as the logarithm of the reference channel output, a differential amplifier connected to the outputs of said logarithmic amplifier and having an output varying as the ratio of the sample channel output over the reference channel output, and output circuit means responsive to the output of said differential amplifier to generator a measure of the concentration of hydrocarbon gas in the sample chamber.
Claim 2
Dependent Claim
209 words
A hydrocarbon gas detector having a monochromatic light source emitting radiation in the region absorbent of hydrocarbon molecules, said beam split into a sample path beam and a reference path beam both directed through a sample chamber along separate paths to a detector means having an output related to the energy in the sample path and reference path, the improvement comprising: a sample channel circuit responsive to the output signal of the detector means related to the sample path, energy for generating a sample channel output, a reference channel circuit responsive to the output signal of the detector means related to the reference path energy for generating a reference channel output, a logarithmic amplifier connected to the output of the sample channel circuit and the reference channel circuit and generating two outputs, one varying as the logarithm of the sample channel output and the second varying as the logarithm of the reference channel output, a differential amplifier connected to the outputs of said logarithmic amplifier and having an output varying as the ratio of the sample channel output over the reference channel output, and output circuit means responsive to the output of said differential amplifier to generator a measure of the concentration of hydrocarbon gas in the sample chamber.
Claim 3
Dependent Claim
41 words
A hydrocarbon gas detector as set forth in claim 1 including an alarm responsive to a predetermined level of output signal from said reference channel circuit to indicate a concentration of hydrocarbon gas in the test chamber above an established level.
Claim 4
Dependent Claim
48 words
A hydrocarbon gas detector as set forth in claim 1 including a gain control adjustment connected to said sample channel circuit to adjust the output thereof to be substantially equal to the output of the reference channel circuit with a hydrocarbon free gas sample in the test chamber.
Claim 5
Dependent Claim
42 words
A hydrocarbon gas detector as set forth in claim 1 including circuit means for timing the response of the sample channel circuit and the reference channel circuit to the detector output only when the respective path energy is applied to said detector.
Claim 6
Dependent Claim
32 words
A hydrocarbon gas detector as set forth in claim 4 wherein said timing means connects said sample channel circuit and said reference channel circuit to the detector output at preselected time intervals.
Claim 7
Dependent Claim
50 words
A hydrocarbon gas detector as set forth in claim 5 wherein said sample channel circuit and said reference channel circuit each include a gated peak detector responsive to the output of the detector means during the preselected time intervals and storing the detector output until a subsequent gating time interval.
Claim 8
Dependent Claim
195 words
A hydrocarbon gas detector having a monochromatic light source emitting radiation in a region absorbent of hydrocarbon molecules, comprising in combination: means for splitting the radiation into a sample path beam and a reference path beam both through a sample chamber containing a gas sample along separate paths, radiant energy detector means responsive to energy in the sample path and the reference path and generating an output signal related to each, a sample channel circuit responsive to the output signal of said detector means related to the sample path energy for generating a sample channel output, a reference channel circuit responsive to the output signal of said detector means related to the reference path energy for generating a reference channel output, means for establishing a timing interval for connecting said sample channel circuit to said detector means to respond only to the sample path energy and for sequentially connecting the reference channel circuit to said detector means to respond only to the reference path energy, and output circuit means responsive to an output from said sample channel circuit and said reference channel circuit to generate a measure of the hydrocarbon gAs in the sample chamber.
Claim 9
Dependent Claim
195 words
A hydrocarbon gas detector having a monochromatic light source emitting radiation in a region absorbent of hydrocarbon molecules, comprising in combination: means for splitting the radiation into a sample path beam and a reference path beam both through a sample chamber containing a gas sample along separate paths, radiant energy detector means responsive to energy in the sample path and the reference path and generating an output signal related to each, a sample channel circuit responsive to the output signal of said detector means related to the sample path energy for generating a sample channel output, a reference channel circuit responsive to the output signal of said detector means related to the reference path energy for generating a reference channel output, means for establishing a timing interval for connecting said sample channel circuit to said detector means to respond only to the sample path energy and for sequentially connecting the reference channel circuit to said detector means to respond only to the reference path energy, and output circuit means responsive to an output from said sample channel circuit and said reference channel circuit to generate a measure of the hydrocarbon gAs in the sample chamber.
Claim 10
Dependent Claim
39 words
A hydrocarbon gas detector as set forth in claim 7 wherein said output circuit means includes a differential amplifier responsive to the output of the sample channel circuit and the reference channel circuit and providing an output related thereto.
Claim 11
Dependent Claim
89 words
A hydrocarbon gas detector as set forth in claim 7 wherein said output circuit means includes a logarithmic amplifier connected to the output of the sample channel circuit and the reference channel circuit and generating two outputs, one varying as the logarithm of the sample channel output and the second varying as the logarithm of the reference channel output, and a differential amplifier connected to the outputs of said logarithmic amplifier and having an output varying as the ratio of the sample channel output over the reference channel output.
Claim 12
Dependent Claim
28 words
A hydrocarbon gas detector as set forth in claim 9 wherein said output circuit means further includes an indicating meter responsive to the output of said differential amplifier.
Claim 13
Dependent Claim
41 words
A hydrocarbon gas detector as set forth in claim 7 including an alarm responsive to a predetermined level of output signal from said reference channel circuit to indicate a concentration of hydrocarbon gas in the sample chamber above an established level.
Claim 14
Dependent Claim
48 words
A hydrocarbon gas detector as set forth in claim 7 including a gain control adjustment connected to said sample channel circuit to adjust the output thereof to be substantially equal to the output of the reference channel circuit with a hydrocarbon free gas sample in the sample chamber.
Claim 15
Dependent Claim
38 words
A hydrocarbon gas detector as set forth in claim 7 wherein said means for establishing a timing interval connects said sample channel circuit and said reference channel circuit to said radiant energy detector means at preselected time intervals.
Claim 16
Dependent Claim
53 words
A hydrocarbon gas detector as set forth in claim 13 wherein said sample channel circuit and said reference channel circuit each include a gated peak voltage detector responsive to the output of said energy detector means during the selected predetermined time intervals and storing the detector output until a subsequent gating time interval.
Claim 17
Dependent Claim
201 words
A hydrocarbon gas detector, comprising in combination: a monochromatic light source emitting radiation in the region absorbent of hydrocarbon molecules, means for splitting the radiation into a sample path beam and a reference path beam, a sample chamber containing a gas sample, a radiant energy detector, means for directing the sample beam through said sample chamber in a first direction to said detector means, means for directing the reference beam through said test chamber in a second separate direction to said detector means, a sample channel circuit responsive to the output signal of said detector related to the sample path energy for generating a sample channel output, a reference channel circuit responsive to the output signal of said detector related to the reference path energy for generating a reference channel output, means for establishing a timing interval for connecting said sample channel circuit to said detector to respond only to the sample channel energy and for connecting the reference path circuit to said detector to respond only to the reference path energy, and output circuit means responsive to an output from said sample channel circuit and said reference channel circuit to generate a measure of hydrocarbon gas in the sample chamber.
Claim 18
Dependent Claim
201 words
A hydrocarbon gas detector, comprising in combination: a monochromatic light source emitting radiation in the region absorbent of hydrocarbon molecules, means for splitting the radiation into a sample path beam and a reference path beam, a sample chamber containing a gas sample, a radiant energy detector, means for directing the sample beam through said sample chamber in a first direction to said detector means, means for directing the reference beam through said test chamber in a second separate direction to said detector means, a sample channel circuit responsive to the output signal of said detector related to the sample path energy for generating a sample channel output, a reference channel circuit responsive to the output signal of said detector related to the reference path energy for generating a reference channel output, means for establishing a timing interval for connecting said sample channel circuit to said detector to respond only to the sample channel energy and for connecting the reference path circuit to said detector to respond only to the reference path energy, and output circuit means responsive to an output from said sample channel circuit and said reference channel circuit to generate a measure of hydrocarbon gas in the sample chamber.
Claim 19
Dependent Claim
32 words
A hydrocarbon gas detector as set forth in claim 15 wherein said means for establishing a timing interval includes means for gating the monochromatic light source on for a preselected time interval.
Claim 20
Dependent Claim
38 words
A hydrocarbon gas detector as set forth in claim 16 wherein said means for splitting the radiation beam into a sample path and a reference path includes triggering means for actuating the means for establishing a timing interval.
Claim 21
Dependent Claim
49 words
A hydrocarbon gas detector as set forth in claim 17 wherein said means for establishing a timing interval includes synchronizing means for connecting said sample channel circuit and said reference channel circuit to the detector output at preselected time intervals during an ''''on'''' cycle of said monochromatic light source.
Claim 22
Dependent Claim
89 words
A hydrocarbon as detector as set forth in claim 15 wherein said output circuit means includes a logarithmic amplifier connected to the output of the sample channel circuit and the reference channel circuit and generating two outputs, one varying as the logarithm of the sample channel output and the second varying as the logarithm of the reference channel output, and a differential amplifier connected to the outputs of said logarithmic amplifier and having an output varying as the ratio of the sample channel output over the reference channel output.
Claim 23
Dependent Claim
41 words
A hydrocarbon gas detector as set forth in claim 19 including an alarm responsive to a predetermined level of output signal from said reference channel circuit to indicate a concentration of hydrocarbon gas in the sample chamber above an established level.
Claim 24
Dependent Claim
47 words
A hydrocarbon gas detector as set forth in claim 20 including a gain control adjustment connected to said sample channel circuit to adjust the output thereof to be substantially equal to the output of the reference channel circuit with a hydrocarbon free sample in the sample chamber.
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) | 1976-09-24 | 1977-03-26 | 1977-09-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-24 | 1981-03-26 | 1981-09-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-24 | 1985-03-26 | 1985-09-25 | $7700.00 | Window Closed / Lapsed |