Stoves and furnaces – Stoves – Heating
Patent
1985-07-29
1987-03-03
Jones, Larry
Stoves and furnaces
Stoves
Heating
126 77, 126112, 126 83, 110211, 110214, 110203, F24C 114
Patent
active
046467122
DESCRIPTION:
BRIEF SUMMARY
This invention relates to solid fuel heating appliances and more particularly to such appliances having high heating efficiency while generating low levels of polluting emissions.
As wood burns in a modern, air tight woodburning stove, products of both complete and incomplete combustion are created containing polluting emissions including particulate material and unburned volatiles which are discharged into the atmosphere and heavier compounds such as creosote which can condense onto the inside surface of the chimney flue. The problem is exacerbated when burning at low heat levels in an oxygen-starved mode. Creosote build up is dangerous in that it can ignite causing a hazardous chimney fire. The particulate emissions are damaging to the environment. Not only do the unburned volatiles have a detrimental impact on the environment, but also the heating value of these unburned volatiles is wasted as the volatiles are discharged into the atmosphere.
In an effort to make a cleaner burning stove with higher thermal efficiency, manufacturers have made stoves employing various techniques for more complete combustion such as secondary combustion chambers and catalytic combustors. Known catalytic combustors usually include a thick, perforate honeycomb structure of ceramic or other material coated with a catalyst material such as platinum, palladium or rhodium. The surface properties of these catalyst materials are such that the combustion products, too cool to burn unaided, will burn within the catalytic combustor. The conventionally known catalytically equipped stoves are so designed that virtually all of the combustion occurring beyond the primary firebox volume occurs within the volume of the catalytic element itself. Combustion ceases downstream of the catalytic element primarily because the region beyond the catalytic element is typically made of a heat conductive material allowing heat to escape thereby quenching further combustion. Since combustion in known stoves with catalytic combustors takes place entirely within the volume of the combustor, these combusters are quite thick. If combustion is not complete by the time the gases have exited the combustor, it is unlikely that any additional combustion will occur. Hence, the thicker, the better was the prevailing rule. However, even though the combustor is perforated, its thickness constitutes a significant flow restriction which increases back pressure.
Solid fuel stoves are also know which employ a secondary combustion chamber for further burning of gases from the primary combustion chamber. Generally, however, woodburning stoves with secondary combustion chambers, even if they are capable of sustaining combustion prior to a log shift, may "wink out" during the exhaust gas composition change due to a shift in the fuel load, for example, by a falling log. Even if the exhaust gases return to the same composition shortly after the distrubing event, the secondary system may not re-ignite if it has cooled down sufficiently in the meantime. In order to maintain secondary combustion and a clean burn in a stove with a conventional secondary combustion chamber, the combination of sensible heat (the temperature of the gases before they enter the secondary chamber) and latent heat (the heat released when the combustible constituents are burned in the secondary) contained in the gas mixture must be high enough to maintain continuous temperatures in the secondary chamber above 1000.degree.-1200.degree. F. If the gas mixture changes temporarily such that the total amount of heat (sensible and latent) available to the secondary chamber is insufficient to maintain the proper chamber temperatures, secondary combustion will cease. The gases will not re-ignite no matter how rich until they are again brought up to a temperature of 1000.degree.-1200.degree. F. when entering the secondary chamber. In general, re-ignition requires operator attention similar to that required during the initial lighting of the secondary chamber. Operation of a stove with a secondary combustion chamb
REFERENCES:
patent: 1399511 (1921-12-01), Moquist
patent: 2781039 (1957-02-01), Kaiser et al.
patent: 2845882 (1958-08-01), Bratton
patent: 3043247 (1962-07-01), Hebert et al.
patent: 3056467 (1962-10-01), Ravich
patent: 3880594 (1975-04-01), Shaw
patent: 4027602 (1977-06-01), Mott
patent: 4039292 (1977-08-01), Morini et al.
patent: 4054411 (1977-10-01), Beck
patent: 4138220 (1979-02-01), Davies et al.
patent: 4249509 (1981-02-01), Syme
patent: 4279629 (1981-07-01), Simms
patent: 4291669 (1981-09-01), Herne, Jr.
patent: 4319556 (1982-03-01), Schwartz et al.
patent: 4330503 (1982-05-01), Allaire et al.
patent: 4332206 (1982-06-01), Tucker et al.
patent: 4345528 (1982-08-01), Allaire et al.
patent: 4363785 (1982-12-01), Willson
patent: 4373507 (1983-02-01), Schwartz et al.
patent: 4380228 (1983-04-01), Crowley
patent: 4385568 (1983-05-01), Murray
patent: 4400356 (1983-08-01), McVay et al.
patent: 4422437 (1983-12-01), Hirschey
patent: 4425305 (1984-01-01), Retallick
patent: 4426992 (1984-01-01), Martenson
patent: 4437451 (1984-03-01), Wysong
patent: 4466358 (1984-08-01), Christian
patent: 4466421 (1984-08-01), Dorsch et al.
patent: 4476852 (1984-10-01), Lee et al.
patent: 4484530 (1984-11-01), Goetzman
patent: 4502395 (1985-03-01), Barnett
"A Catalytic Converter You Can Build," The Mother Earth News, Jan.-Feb. 1983, pp. 163-165.
Riteway's Uni-Com Brochure, 1983.
Smokemaster brochure, Dorwood Industries Ltd.
Smoke Genie brochure, Arden Industries, Inc., 1983.
In-Ten'si-Fire Owner's Manual, Catalytic Damper Corporation.
Versagrid brochure, Applied Ceramics, Inc.
Hart Fireplace Furnishings brochure, Form No. 1200-A.
The Shelburne Catalytic brochure, The Vermont Stove Company.
Andors Derik K.
Crossman, Jr. William W.
Ferguson Robert W.
Jones Larry
Vermont Castings, Inc.
LandOfFree
Solid fuel heating appliances does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Solid fuel heating appliances, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Solid fuel heating appliances will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1011106