Patent US3789805A successfully refreshed from Google Patents.
US3789805A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Burner and heat exchanger
Assignee: Massachusetts Institute of Technology
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Filing: 1972-05-17
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Granted: 1974-02-05
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Expires: 1992-05-17
Abstract
Abstract A combination burner and heat exchanger has a first combustion zone for hot gaseous flow adjacent the burner, a first stage of heat exchanger in and terminating this zone and adapted to cool the flow to a temperature too low to support formation of certain undesired components therein but sufficiently high to support combustion of other undesired components, a second combustion zone, longer than the first, wherein the flow is maintained at a temperature sufficiently high to support such combustion, and a second stage of heat exchanger wherein the flow exiting the second combustion stage is cooled below the combustion temperature.
Inventors
- 👤 G Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:22
CPC Classifications
F; F22; F22B; F22B31/00; F24; F24H; F24H1/00; F24H1/22; F24H1/40; F24H9/00; F24H9/18; F24H9/1809; F24H9/1832; F24H9/1836
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
223 words
In a combination high intensity burner and heat exchanger unit, the burner connected to a supply for a mixture of vaporous or vaporizable fuel and excess air of a quantity to sustain complete combustion while attaining temperatures of the order of 2,000*K and wherein the burner is arranged to provide a hot gaseous flow including combustion products at an elevated temperature above a first temperature which supports combustion of certain undesired components and above a second higher temperature which supports formation of nitrogen oxides, and the heat exchanger is arranged in the gaseous flow to extract heat therefrom, the improvement which includes: means defining a first combustion zone for said gaseous flow adjacent said burner; a first stage of heat exchanger disposed in and terminating said first combustion zone and adapted to cool the gaseous flow to a temperature in the range of about 1,600-1,800*K, below said second temperature but above said first temperature; means defining a second combustion zone for said gaseous flow immediately following and longer than said first combustion zone and adapted to maintain said gaseous flow above said first temperature; and a further stage of heat exchanger disposed in the path of gaseous flow terminating said second combustion zone and adapted to cool the gaseous flow below said first temperature, the only entry for combustion air being said supply.
Claim 2
Dependent Claim
223 words
In a combination high intensity burner and heat exchanger unit, the burner connected to a supply for a mixture of vaporous or vaporizable fuel and excess air of a quantity to sustain complete combustion while attaining temperatures of the order of 2,000*K and wherein the burner is arranged to provide a hot gaseous flow including combustion products at an elevated temperature above a first temperature which supports combustion of certain undesired components and above a second higher temperature which supports formation of nitrogen oxides, and the heat exchanger is arranged in the gaseous flow to extract heat therefrom, the improvement which includes: means defining a first combustion zone for said gaseous flow adjacent said burner; a first stage of heat exchanger disposed in and terminating said first combustion zone and adapted to cool the gaseous flow to a temperature in the range of about 1,600-1,800*K, below said second temperature but above said first temperature; means defining a second combustion zone for said gaseous flow immediately following and longer than said first combustion zone and adapted to maintain said gaseous flow above said first temperature; and a further stage of heat exchanger disposed in the path of gaseous flow terminating said second combustion zone and adapted to cool the gaseous flow below said first temperature, the only entry for combustion air being said supply.
Claim 3
Dependent Claim
30 words
The unit of claim 1 wherein the residence time of the gas in said second combustion zone is at least several times its residence time in said first combustion zone.
Claim 4
Dependent Claim
46 words
The unit of claim 1 wherein said burner includes a perforated wall member and means to feed a fuel-air mixture through said wall member to form flames, and the spacing of said first stage of heat exchanger from said wall member is less than 3 inches.
Claim 5
Dependent Claim
12 words
The unit of claim 3 wherein said spacing is about 1 inch.
Claim 6
Dependent Claim
188 words
In a combination burner and heat exchanger unit wherein the burner is arranged to provide a hot gaseous flow including combustion products at an elevated temperature above a first temperature which supports combustion of certain undesired components and above a second higher temperature which supports formation of other undesired components, and the heat exchanger is arranged in the gaseous flow to extract heat therefrom, the improvement which includes: means defining a first combustion zone for said gaseous flow adjacent said burner; a first stage of heat exchanger disposed in and terminating said first combustion zone and adapted to cool the gaseous flow to a temperature below said second temperature but above said first temperature; means defining a second combustion zone for said gaseous flow immediately following and longeR than said first combustion zone and adapted to maintain said gaseous flow above said first temperature; and a further stage of heat exchanger disposed in the path of gaseous flow terminating said second combustion zone and adapted to cool the gaseous flow below said first temperature and which includes means for adjustably changing the length of said first combustion zone.
Claim 7
Dependent Claim
188 words
In a combination burner and heat exchanger unit wherein the burner is arranged to provide a hot gaseous flow including combustion products at an elevated temperature above a first temperature which supports combustion of certain undesired components and above a second higher temperature which supports formation of other undesired components, and the heat exchanger is arranged in the gaseous flow to extract heat therefrom, the improvement which includes: means defining a first combustion zone for said gaseous flow adjacent said burner; a first stage of heat exchanger disposed in and terminating said first combustion zone and adapted to cool the gaseous flow to a temperature below said second temperature but above said first temperature; means defining a second combustion zone for said gaseous flow immediately following and longeR than said first combustion zone and adapted to maintain said gaseous flow above said first temperature; and a further stage of heat exchanger disposed in the path of gaseous flow terminating said second combustion zone and adapted to cool the gaseous flow below said first temperature and which includes means for adjustably changing the length of said first combustion zone.
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) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |