US3793525A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dual cell non-dispersive gas analyzer
Assignee: Lanteris Space LLC
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Filing: 1973-01-02
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Granted: 1974-02-19
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Expires: 1993-01-02
Abstract
Abstract In a gas analyzer a beam of radiant energy, chopped at a suitable frequency, and limited by filter means to a suitable portion of the spectrum, is passed through a sample region containing an unknown quantity of gas to be analyzed. Selector cells are alternately inserted into the beam at a rate substantially lower than the chopping frequency. One selector cell contains a quantity of the gas species to be analyzed at high pressure and the other contains a quantity of the same gas at low pressure. A photo detector converts the radiant energy variations to electrical signals which can be analyzed to indicate the quantity of gas in the sample region.
Inventors
- 👤 D Burch
- 👤 D Gryvnak
- 👤 J Pembrook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:03
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/3504; G01N21/3518
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
222 words
A radiant energy gas analyzer comprising: a source of radiant energy, means for modulating said radiant energy at a first frequency, means for passing said radiant energy through a region containing a gas to be analyzed, means for filtering said radiant energy to confine the transmitted radiant energy to a portion of the spectrum where said gas to be analyzed displays absorption lines, means for switching said radiant energy between two channels at a second frequency, means in a first channel for passing radiant energy through a first selector cell adapted to contain a quantity of said gas to be analyzed at a first pressure, means in a second channel for passing radiant energy through a second selector cell adapted to contain a quantity of said gas to be analyzed at a second pressure higher than said first pressure, means for adjusting the radiant energy in said two channels to obtain equal average transmission in the absence of said gas to be analyzed in said region, means for converting the radiant energy in said two channels to electrical energy, and means for analyzing said electrical energy to provide an indication of the ratio of signal at said second frequency to signal at said first frequency, said ratio being proportional to the quantity of said gas to be analyzed in said sample region.
Claim 2
Dependent Claim
222 words
A radiant energy gas analyzer comprising: a source of radiant energy, means for modulating said radiant energy at a first frequency, means for passing said radiant energy through a region containing a gas to be analyzed, means for filtering said radiant energy to confine the transmitted radiant energy to a portion of the spectrum where said gas to be analyzed displays absorption lines, means for switching said radiant energy between two channels at a second frequency, means in a first channel for passing radiant energy through a first selector cell adapted to contain a quantity of said gas to be analyzed at a first pressure, means in a second channel for passing radiant energy through a second selector cell adapted to contain a quantity of said gas to be analyzed at a second pressure higher than said first pressure, means for adjusting the radiant energy in said two channels to obtain equal average transmission in the absence of said gas to be analyzed in said region, means for converting the radiant energy in said two channels to electrical energy, and means for analyzing said electrical energy to provide an indication of the ratio of signal at said second frequency to signal at said first frequency, said ratio being proportional to the quantity of said gas to be analyzed in said sample region.
Claim 3
Dependent Claim
16 words
The apparatus of claim 1 wherein said second frequency is substantially lower than said first frequency.
Claim 4
Dependent Claim
37 words
The apparatus of claim 1 wherein said means for converting said radiant energy to electrical energy is a photodetector feeding an electronic circuit comprising: a broadband amplifier, and synchronous demodulators operating at said first and second frequencies.
Claim 5
Dependent Claim
70 words
The apparatus of claim 1 wherein said means for converting said radiant energy to electrical energy is a photodetector feeding an electronic circuit comprising: a bandpass amplifier tuned to said first frequency, a demodulator connected to said bandpass amplifier, means connected to said demodulator to produce a d-c signal related to said second frequency, and means connected to said demodulator to produce a d-c signal related to said first frequency.
Claim 6
Dependent Claim
217 words
In a dual channel analyzer of a particular gas in a sample, said analyzer including a radiant energy source and a single radiant energy detector, the improvement comprising: a. means for confining the energy of said source to a predetermined spectral range, b. means for passing said energy through a sample region that may contain a quantity of said gas, c. means for applying said energy alternately to two channels at a first frequency, d. means for passing the energy in one of said two channels through a selector cell adapted to contain a quantity of said gas at a first pressure, e. means for passing the energy in the other of said two channels through a selector cell adapted to contain a quantity of said gas at a second, lower pressure, f. means for equalizing the average transmittance of said two channels in the absence of said gas in said sample region, g. means for modulating said source at a second frequency, said second frequency being higher than said first frequency, and h. electrical circuit means connected to said detector for indicating the ratio of the amplitude of said first frequency signal component to the amplitude of said second frequency signal component, said ratio being proportional to said quantity of said gas in said sample region.
Claim 7
Dependent Claim
217 words
In a dual channel analyzer of a particular gas in a sample, said analyzer including a radiant energy source and a single radiant energy detector, the improvement comprising: a. means for confining the energy of said source to a predetermined spectral range, b. means for passing said energy through a sample region that may contain a quantity of said gas, c. means for applying said energy alternately to two channels at a first frequency, d. means for passing the energy in one of said two channels through a selector cell adapted to contain a quantity of said gas at a first pressure, e. means for passing the energy in the other of said two channels through a selector cell adapted to contain a quantity of said gas at a second, lower pressure, f. means for equalizing the average transmittance of said two channels in the absence of said gas in said sample region, g. means for modulating said source at a second frequency, said second frequency being higher than said first frequency, and h. electrical circuit means connected to said detector for indicating the ratio of the amplitude of said first frequency signal component to the amplitude of said second frequency signal component, said ratio being proportional to said quantity of said gas in said sample region.
References Cited (Backward Citations)
US3488491A
Cited
US3588496A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |