WOODKILN MOLDED COMBUSTION CHAMBER
The molded combustion chamber described herein is an improvement on prior art with a number of significant advantages. A single molded piece replaces many fabricated pieces of board and brick with uniformity of material and lower cost. It can be used by itself as a replacement for a grate in a wood/gas fireplace or as the key element of a metal or masonry fabricated fireplace. It can be molded up to 3″ in thickness, so that the focus can be on insulation and reflection rather than surface durability. The spherical baffle serves as a secondary combustion area, so that all flames are visible and significantly more heat is radiated into the living space. This design is more efficient and less costly than most EPA certified wood heaters with a secondary combustion chamber or catalytic converter. This design will also help a gas appliance meet the DOE efficiency goal. The absence of a grate and the insulating quality of the material used enable a very small coal bed to ignite new fuel. This is user friendly and facilitates the loading of a single large (all-nighter) log for a slow burn. The top of the chamber is flat for heating water and food. This design could be used in a large fireplace and would be particularly useful in underdeveloped parts of the world where there is no other means of cooking than a fire.
The present invention relates in general to combustion chambers and more particularly a wood kiln molded combustion chamber.
BACKGROUND OF THE INVENTIONFor background reference is made to the following patents.
An efficient fireplace (EFP) is herein defined as having an insulated combustion chamber and a large glass door to provide a full view of the fire with a high percentage of its heat radiated through the glass. U.S. Pat. No. 4,681,087 illustrates such a construction. (The consumer will buy it for efficiency and cleanliness as well as the feel of radiant heat and view of the fire.)
When the Clean Air Act authorized the EPA to regulate wood burning (1983) no such product existed. The resulting regulation required a wood heater to burn a load of Douglas Fir (2×4s and 4×4s spaced 1.5″ apart) at a very slow rate and defined a fireplace as being very inefficient. Some clever engineering took place resulting in rather complex, airtight, costly and unattractive units such as described in U.S. Pat. No. 4,766,876. The overall result was a decline (much greater than anticipated by the regulators) in new wood burning sales except for exempt units such as outdoor boilers. There are no efficient and low cost wood burning fireplaces. The sales of gas and electric fireplaces have experienced significant growth.
An early version of WoodKiln designed specifically to be a wood heater was the first to be certified to the 1990 standard. However, it was ugly and did not achieve this applicant's goal of an EFP. A later version failed the certification test—not because it was bad for air quality, but because it would not burn slowly enough to be a certified wood heater nor inefficiently enough to be an exempt fireplace.
The EPA is undertaking a 20 year review of its regulation. However, its primary emphasis seems to be to extend the regulation to currently exempt products as opposed to encouraging efficiency and innovation.
In addition to the wood heater test protocol, EPA is relying on an ASTM fireplace test in which it had significant input. Neither of these protocols is realistic for a WoodKiln EFP. They both call for a starting coal bed weight of 20% of the wet weight of the next load. EFP experience says that 5% to 10% is more realistic in terms of user friendliness and getting the new fuel started. The EPA and ASTM protocols both involve spacing the fuel in an unrealistic manner. The net result is to destroy the secondary combustion function of the WoodKiln combustion chamber. Neither protocol includes efficiency in the certification process.
This application involves the concept of a molded combustion chamber for use in an EFP, but which can also be marketed as a replacement for the grate or gas logs in most any fireplace with or without the blessing of the EPA. It also might provide a low cost, clean and efficient cook stove for underdeveloped parts of the world.
According to the invention, there is a combustion chamber of a single molded shape. The bottom slopes to the rear and the rear is vertical to the bottom. There may be a spherical top that slopes from just above the fuel location in the rear to the full height at the front center. The top front may be constructed and arranged to be used for cooking. An optional gas burner may be installed in the combustion chamber. A metal liner tray may be placed on the bottom for increased durability. The material of the combustion chamber may be a light weight insulating refractory which encourages complete combustion and radiates heat onto the fuel and out the front. The combustion chamber may be a replacement for a fireplace grate. There may be a small coal bed supporting a single large log for a slow burn. The combustion chamber may be incorporated into a low cost prefabricated fireplace insert or a masonry fireplace. Numerous other features, objects and advantages will become apparent from the following detailed description when read in connection with the accompanying drawing in which:
The bottom 2 is sloped to the rear to prevent logs and coals from rolling out the front without the need for a grate. The rear 3 is sloped to maximize radiant heat out the front. The top 4 is sloped in a spherical fashion to the top front to provide a long hot path for complete combustion in full view, eliminate the need for a secondary combustion chamber or a catalytic converter and maximize radiant heat out the front. The front of the top 5 is flat with a recess focusing the hot gas out the middle so that it can be used for cooking. An optional gas burner 6 similar to U.S. Pat. No. 5,391,074 can be added for starting a wood fire or as a source of heat without burning wood.
There has been described a novel wood kiln molded combustion chamber. It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific embodiment described herein without departing from the inventive concept. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or possessed by the apparatus and techniques herein disclosed and limited solely by the spirit and scope of the appended claims.
Claims
1-10. (canceled)
11. A combustion chamber of a single molded shape.
12. A combustion chamber in accordance with claim 11 having a bottom surface and a rear surface with the bottom surface sloping to the rear surface and the rear surface extending vertically from the bottom surface.
13. A combustion chamber in accordance with claim 11 having a spherical top that slopes from just above the bottom surface to the full height at the front center of the combustion chamber.
14. A combustion chamber in accordance with claim 11 and further comprising a gas burner within said combustion chamber.
15. A combustion chamber in accordance with claim 11 and further comprising a metal liner tray on the bottom surface.
16. A combustion chamber in accordance with claim 11 made of light weight insulating refractory material.
17. A combustion chamber in accordance with claim 11 and further comprising a small coal bed on the bottom surface supporting a single large log.
18. A combustion chamber in accordance with claim 11 having a top formed with a recess focusing the hot gas out the middle so that it can be used for cooking.
Type: Application
Filed: Jun 13, 2011
Publication Date: Dec 13, 2012
Inventor: John G. Meeker (Kent, CT)
Application Number: 13/158,968
International Classification: F23M 5/00 (20060101); F23M 99/00 (20100101);