US4437005A
Expired / Lapsed
US
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Nondispersive infrared gas analyzer
Assignee: Siemens AG
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Filing: 1981-11-17
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Granted: 1984-03-13
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Expires: 2001-11-17
Abstract
Abstract A nondispersive infrared gas analyzer of the type wherein gas-filled chambers are arranged in the path of modulated infrared radiation. A measurement pickup is provided for producing a signal responsive to the response of a gas contained in the chamber to the infrared radiation. The infrared radiation is produced by a source of infrared radiation which is powered by a pulsed energy supply, the pulsed energy supply being responsive to control signals so as to provide pulses which have a duty cycle which is less than 1, and preferably between 0.1 and 0.5. The duration of the pulses is controlled in response to the maximum value of a measuring signal of an output of a measuring pickup. In other embodiments, the duration of the pulses may be determined empirically, by calculation, or by means of peak detector. This arrangement provides almost 100% modulation while considerably reducing power consumption and without loss of sensitivity. As such, the invention is particularly useful in battery-operated nondispersive infrared gas analyzer equipment adapted for field use.
Inventors
- 👤 Paul-Arthur Ophoff
- 👤 Johann Weinel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:17
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/31; G01N21/35; G01N21/37; G01N21/59; G01N21/61
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
121 words
A nondispersive infrared gas analyzer of the type having a plurality of gas-filled chambers arranged in the propagation path of modulated infrared radiation, and a measuring pickup for producing an electrical measurement signal, the nondispersive infrared gas analyzer further comprising: pulsed energy supply means for producing electrical pulses having a duty cycle which is less than 1; infrared radiation means for producing infrared radiation which is modulated in response to said duty cycle of said pulsed energy supply means, said infrared radiation means having a predetermined continuous power rating; and pulse control means for terminating each of said electrical pulses from said pulsed energy supply means in response to a peak value of a corresponding pulse in the electrical measurement signal.
Claim 2
Dependent Claim
121 words
A nondispersive infrared gas analyzer of the type having a plurality of gas-filled chambers arranged in the propagation path of modulated infrared radiation, and a measuring pickup for producing an electrical measurement signal, the nondispersive infrared gas analyzer further comprising: pulsed energy supply means for producing electrical pulses having a duty cycle which is less than 1; infrared radiation means for producing infrared radiation which is modulated in response to said duty cycle of said pulsed energy supply means, said infrared radiation means having a predetermined continuous power rating; and pulse control means for terminating each of said electrical pulses from said pulsed energy supply means in response to a peak value of a corresponding pulse in the electrical measurement signal.
Claim 3
Dependent Claim
31 words
The nondispersive infrared gas analyzer of claim 1 wherein said duty cycle of said electrical pulses from said pulsed power supply means is within a range of between 0.1 to 0.5.
Claim 4
Dependent Claim
46 words
The nondispersive infrared gas analyzer of claim 1 wherein said infrared radiation means is operated to produce the modulated infrared radiation in pulses of infrared radiation having a maximum amplitude value which corresponds to several times said predetermined continuous power rating of said infrared radiation means.
Claim 5
Dependent Claim
114 words
The nondispersive infrared gas analyzer of claims 1, 2, or 3, wherein there are further provided: monostable power switch means having a first terminal for coupling to a source of electrical energy, a second terminal for coupling to said infrared radiation means, and a third terminal for receiving control signals; pulse generator means for producing said control signals at said third terminal of said monostable power switch means, said control signals having pulses of selectable duration; and clock generator means for producing periodic clock pulses having a period corresponding to the sum of said duration of one pulse in said control signals, and the duration of an interval between consecutive ones of said pulses.
Claim 6
Dependent Claim
133 words
The nondispersive infrared gas analyzer of claim 1 wherein there are further provided: bistable power switch means having a first terminal for coupling to a power supply, a second terminal for coupling to said infrared radiation source, and a third terminal for receiving control signals; clock generator means for producing said control signals to said third terminal of said bistable power switch means, said control signal being formed of periodic clock pulses having a period which corresponds to the sum of the duration of one of said clock pulses and the duration of an interval between consecutive ones of said clock pulses; and maximum value detector means responsive to the electrical measurement signal for producing an output signal which defines a time at which said bistable power switch means changes its conductive state.
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) | 1987-03-13 | 1987-09-12 | 1988-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-13 | 1991-09-12 | 1992-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-13 | 1995-09-12 | 1996-03-13 | $7700.00 | Window Closed / Lapsed |