Patent US4194487A successfully refreshed from Google Patents.
US4194487A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Downdraft woodburning stove
Assignee: Individual
•
Filing: 1976-08-02
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Granted: 1980-03-25
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Expires: 1996-08-02
Abstract
Abstract A downdraft woodburning stove in which there is improved combustion, heat transfer and combustion regulation comprising novel air inlet circulation, grate construction and automatic control of (1) temperature of exhaust gases and (2) of combustion air, and (3) the supplies of both primary and secondary air to a plurality of combustion areas.
Inventors
- 👤 John Y. Cadwallader
- 👤 Edward J. Frasier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:47
CPC Classifications
F; F24; F24B; F24B5/00; F24B5/02; F24B5/04; F24B1/00; F24B1/02; F24B1/16
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
115 words
A downdraft stove comprising a stove body within which are one or more slanting grates with means for supporting same in said body and also within which are internal members of one or more walls extending upwards from a point above the lowest point of said slanting grates so as to form a space between said members and grates with at least one air inlet nozzle below said grates, one or more air inlet nozzles above said grates and longitudinal elements above said nozzles to provide a clear passageway for combustion air whereby progressively burning coals descend to said space and whereby all smoke, air and gases pass through said space insuring their complete ignition.
Claim 2
Dependent Claim
115 words
A downdraft stove comprising a stove body within which are one or more slanting grates with means for supporting same in said body and also within which are internal members of one or more walls extending upwards from a point above the lowest point of said slanting grates so as to form a space between said members and grates with at least one air inlet nozzle below said grates, one or more air inlet nozzles above said grates and longitudinal elements above said nozzles to provide a clear passageway for combustion air whereby progressively burning coals descend to said space and whereby all smoke, air and gases pass through said space insuring their complete ignition.
Claim 3
Dependent Claim
32 words
The combination according to claim 1 with a single air inlet nozzle below said grates and with a single longitudinal element above said nozzle to provide a clear passageway for combustion air.
Claim 4
Dependent Claim
53 words
The combination according to claim 1 wherein the space between said internal members and the outer walls of said stove body comprises an exhaust gas chamber which extends down both sides and around the rear of said stove body and connects to a flue at the rear through which burnt gases are exhausted.
Claim 5
Dependent Claim
61 words
The combination according to claim 1 wherein said internal members are comprised of two or more walls joined so as to form a heat exchange chamber the air inside of which will be totally isolated from combustion air and which can be connected to a suitable blower or which can be provided with openings for passage of air by natural convection.
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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) | 1983-03-25 | 1983-09-24 | 1984-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-25 | 1987-09-24 | 1988-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-25 | 1991-09-24 | 1992-03-25 | $7700.00 | Window Closed / Lapsed |