US4403574A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Boiler pancake design
Assignee: Individual
•
Filing: 1981-06-10
•
Granted: 1983-09-13
•
Expires: 2001-06-10
Abstract
Abstract A device constituting an improved boiler design. The heat exchanger, known in the art as a pancake, is composed of an asymmetrical grid of interconnected hollow eliptical conduits through which flow the heat transfer fluid. In one embodiment of the invention, two pancakes are connected in series in such a way that their asymmetry is complementary. Such an arrangement is claimed to increase the efficiency of heat transfer and reduce the frequency of cleaning of the boiler when compared to boilers in the known art.
Inventors
- 👤 Stephen Free
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:15
CPC Classifications
F; F24; F24H; F24H1/00; F24H1/22; F24H1/38
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
83 words
A direct fired boiler device comprising: a firebox in which coal, wood or other suitable fuel is burned to produce combustion products; a series of two or more heat transfer devices maintained above said firebox, each said heat transfer devices comprising interconnected grid patterns of hollow elliptical-shaped conduits with their respective major axes parallel to the flow path of said combustion produts, said grid pattern being asymmetrical; and a chimney in communication with said firebox to convey said combustion products from the boiler.
Claim 2
Dependent Claim
83 words
A direct fired boiler device comprising: a firebox in which coal, wood or other suitable fuel is burned to produce combustion products; a series of two or more heat transfer devices maintained above said firebox, each said heat transfer devices comprising interconnected grid patterns of hollow elliptical-shaped conduits with their respective major axes parallel to the flow path of said combustion produts, said grid pattern being asymmetrical; and a chimney in communication with said firebox to convey said combustion products from the boiler.
Claim 3
Dependent Claim
53 words
A boiler, according to claim 1, wherein two or more heat transfer devices of asymmetrical design are stacked in series in such a way that their asymmetry is complementary in whole or in part such that, when taken in immediately adjacent stacked pairs, the resultant grid pattern of the stacked pairs is symmetrical.
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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) | 1986-09-12 | 1987-03-14 | 1987-09-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-12 | 1991-03-14 | 1991-09-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-12 | 1995-03-14 | 1995-09-13 | $7700.00 | Window Closed / Lapsed |