US3708674A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combustion detector
Assignee: National Aeronautics and Space Administration
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Filing: 1971-04-16
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Granted: 1973-01-02
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Expires: 1991-04-16
Abstract
Abstract A device for generating a rapid response signal upon the radiation-emitting combustion reaction of certain gases (or other materials) in order to provide a means for the detection and identification of such reaction and concurrently discriminate against spurious signals. This combustion might be the first stage of a coal mine explosion process, and thereby this device could provide a warning of the impending explosion in time to initiate quenching action. This device has the capability of distinguishing between the light emitted from a combustion reaction and the light emitted by miners'' lamps, electric lamps, welding sparks or other spurious events so that the quenching mechanism is triggered only when an explosion-initiating combustion occurs.
Inventors
- 👤 R Trimpi
- 👤 J Nealy
- 👤 W Grose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:54
CPC Classifications
E; E21; E21F; E21F17/00; E21F17/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
220 words
Apparatus for indicating that a radiation emitting combustion reaction of a predetermined type has occurred in a selected area comprising: optical means for collecting light for all combustions that occur in said selected area; means for spectrally separating said collected light into first and second separate narrow wave length regions with the center of said first wavelength region being at lambda and with the center of said second wavelength region being in the range of 0.9 lambda to 1.1 lambda , said first wavelength region being one of relatively high emission for said predetermined type of combustion reaction and concurrently for all spurious light sources the emission from the first wave length region being approximately equal to or less than the emission in the second wavelength region; means for producing a first signal whose amplitude is proportional to the emission in said first wavelength region and a second signal whose amplitude is proportional to the emission in said second wavelength region; and a subtractor receiving said first and second signals for producing an electrical signal whose amplitude is proportional to the difference in amplitudes of said first and second signals whereby whenever the amplitude of said electrical signal exceeds a predetermined value there is an indication that a combustion reaction of said predetermined type has occurred in said selected area.
Claim 2
Dependent Claim
220 words
Apparatus for indicating that a radiation emitting combustion reaction of a predetermined type has occurred in a selected area comprising: optical means for collecting light for all combustions that occur in said selected area; means for spectrally separating said collected light into first and second separate narrow wave length regions with the center of said first wavelength region being at lambda and with the center of said second wavelength region being in the range of 0.9 lambda to 1.1 lambda , said first wavelength region being one of relatively high emission for said predetermined type of combustion reaction and concurrently for all spurious light sources the emission from the first wave length region being approximately equal to or less than the emission in the second wavelength region; means for producing a first signal whose amplitude is proportional to the emission in said first wavelength region and a second signal whose amplitude is proportional to the emission in said second wavelength region; and a subtractor receiving said first and second signals for producing an electrical signal whose amplitude is proportional to the difference in amplitudes of said first and second signals whereby whenever the amplitude of said electrical signal exceeds a predetermined value there is an indication that a combustion reaction of said predetermined type has occurred in said selected area.
Claim 3
Dependent Claim
48 words
Apparatus according to claim 1 wherein said predetermined type of combustion reaction is a methane-air mixture type; said selected area is an area in a coal mine; said first wavelength region is a narrow region around 3,064A; and said second wavelength region is a narrow region around 3,000A.
Claim 4
Dependent Claim
13 words
Apparatus according to claim 1 wherein a divider is substituted for said subtractor.
Claim 5
Independent Claim
225 words
A method for indicating that a radiation emitting combustion reaction of a predetermined type has occurred in a selected area comprising the steps of: collecting light from all combustions that occur in said selected area; spectrally separating said collected light into first and second separate narrow wavelength regions with the center of said first wavelength region being at lambda and with the center of said second wavelength region being in the range of 0.9 lambda to 1.1 lambda , said first wavelength region being one of relatively high emission for said predetermined type of combustion reaction and said second wavelength region being one of relatively low emission for said predetermined type of combustion reaction and concurrently for all spurious light sources the emission from the first wavelength region being approxImately equal to or less than the emission in the second wavelength region; producing a first signal whose amplitude is proportional to the emission in said first wavelength region; producing a second signal whose amplitude is proportional to the emission in said second wavelength region; and producing an electrical signal whose amplitude is proportional to the difference in the amplitudes of said first and second signals whereby whenever the amplitude of said electrical signal exceeds a predetermined value there is an indication that a combustion reaction of said predetermined type has occurred in said selected area.
Claim 6
Independent Claim
225 words
A method for indicating that a radiation emitting combustion reaction of a predetermined type has occurred in a selected area comprising the steps of: collecting light from all combustions that occur in said selected area; spectrally separating said collected light into first and second separate narrow wavelength regions with the center of said first wavelength region being at lambda and with the center of said second wavelength region being in the range of 0.9 lambda to 1.1 lambda , said first wavelength region being one of relatively high emission for said predetermined type of combustion reaction and said second wavelength region being one of relatively low emission for said predetermined type of combustion reaction and concurrently for all spurious light sources the emission from the first wavelength region being approxImately equal to or less than the emission in the second wavelength region; producing a first signal whose amplitude is proportional to the emission in said first wavelength region; producing a second signal whose amplitude is proportional to the emission in said second wavelength region; and producing an electrical signal whose amplitude is proportional to the difference in the amplitudes of said first and second signals whereby whenever the amplitude of said electrical signal exceeds a predetermined value there is an indication that a combustion reaction of said predetermined type has occurred in said selected area.
Claim 7
Dependent Claim
56 words
A method according to claim 4 wherein the step of producing an electrical signal whose amplitude is proportional to the ratio of the amplitudes of said first and second signals is substituted for the step of producing an electrical signal whose amplitude is proportional to the difference in the amplitudes of said first and second signals.
Claim 8
Dependent Claim
49 words
A method according to claim 4 wherein said predetermined type of combustion reaction is a methane-air mixture type; said selected area is an area in a coal mine; said first wavelength region is a narrow region around 3,064A; and said second wavelength region is a narrow region around 3,000A.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |