Apparatus and method for combustion

Abstract

To enable a burnpot for a corn burning stove to be continuously operated, the burnpot has either: (1) an openable bottom with at least a first and second position, one of the at least first and second positions being substantially closed to enable a body of combustible fuel to burn on its upper surface, the other of the at least first and second positions providing an opening, burnpot side wall portions and a top of the burnpot being shaped so as to permit a solid clinker to drop out of the opening in the openable bottom when the openable bottom is in its second position; or (2) a bottom formed as one of a series of sections of a rotatable member so that as the member rotates, it carries ash with it away from the bottom of the burnpot. A combustion volume is provided between the openable bottom or rotatable bottom, the side surfaces and the top, the combustion volume having an upper portion and a lower portion whereby a fire on a combustion surface in the lower portion burns upwardly toward the upper portion so that byproducts of combustion build on the combustion surface to cause burning fuel to burn at a higher level; the higher level having a smaller cross sectional area than the lower portion whereby the byproducts of combustion may drop as a unit out of the burnpot bottom opening. Easy to ignite fuel is moved from one hopper into the burnpot and ignited. When the temperature is high enough to ignite the harder to ignite fuel it is moved into the burnpot and the flow of easy to ignite fuel stopped.

Description

RELATED CASES [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 410,118 filed Apr. 9, 2003, and this application is a continuation-in-part of provisional patent application 60 / 779,750 filed Mar. 7, 2006, both in the name of Terry L. Krumrei. Applicant claims the benefit of the filing date of provisional patent application 60 / 779,750 filed Mar. 7, 2006.BACKGROUND OF THE INVENTION [0002] This invention relates to methods and apparatuses for combustion and more particularly to a combustion technique and equipment including a burnpot system, a fuel hopper and a method of operating the burnpot system and fuel hopper. [0003] It is known to provide a combustion system for removing ash conveniently from the bottom of a burnpot with moving walls. The prior art moving walls slide open or swing open, either completely open such as by sliding out of the bottom or partly open such as in the case of moveable grates that move back and forth to open and close....

AI Technical Summary

Benefits of technology

[0011] In one embodiment, the surface of the cylinder is divided into four sections of 90 degrees each. In another embodiment, it is divided into three sections. The newly added fuel is ignited and burns on the top surface of the section closing the burnpot bottom for a period of time short enough to avoid excessive concentration of heat and high temperatures. Because the top fuel burns first, the temperature of the surface of the cylinder is not heated excessively. The cylinder may be rotated before the newly added fuel has been thoroughly burned. The number of sections on the drum and the rate of rotation may be selected for the fuel that is to be burned. It is also possible to control the air flow. These options are selected to avoid excessive heat that may cause some fuels to develop clinkers that attach too strongly to the drum or walls of the burnpot. Scrapers and / or cutting members may be incorporated to remove ash from the drum after it has rotated beyond the bottom of the burnpot. Ash containing unburned fuel may be recirculated if desired.

[0013] With this approach, the area and time of burning are spread. The metal surface of the cylinder does not rise to as high a temperature because the burning is spaced from the bottom by fuel that is not yet ignited before the cylinder is rotated and after the cylinder is rotated, the fuel is not pressed against the bottom of the cylinder by gravity but instead is repositioned. The lower concentration of heat avoids binding of the fuel with the surface of the cylinder and reduces melting of the fuel to form large clinkers. Further rotation of the cylinder causes the ash to drop from the ash removing section of the burnpot. A mounting structure is positioned with respect to the cylinder so that the cylindrical surface always closes the burnpot at the bottom end of the burnpot. The cylinder extends sufficiently beyond the opening at the lower end of the burnpot to carry the products of combustion out of the burnpot when the rotatable cylinder is rotated.

[0018] Instead of rotating about a horizontal axis, the ash removing section may rotate about a vertical axis. In this embodiment, there are two or more sections with one section closing the bottom of the burner and the other section permitting ash to drop from the burnpot. In the latter embodiment, the burnpot is shaped with the largest portion at the bottom to permit clinkers to fall from the burnpot freely. This may be combined with a similarly rotating retention slide so that the burning fuel is maintained on the retention slide while the ash removing system has an opening bottom section in position to permit ash and clinkers to fall out of the burnpot and rotated to an open position when the ash removing section is closed to receive the burning coals. If corn or other hard to ignite biomass is the fuel, the automatic ignition system with a hopper containing easily ignited fuel such as wood and a second hopper containing the harder to ignite biomass as described above may be used.

[0019] From the above description, it can be understood that the burnpot of the invention and stoves that accommodate it have several advantages, such as: (1) a continuous flame may be maintained while byproducts of burning are automatically removed; (2) difficult to ignite fuels may be ignited automatically; and (3) biomass such as corn that, when burnt, has a tendency to cause ash to stick to the burnpot may be utilized.

Problems solved by technology

The prior art systems of this type are difficult to operate automatically for long periods of time.

This approach works well with some fuels such as wood pellets but not for others such as corn or other unconventional biomass fuels which have higher ignition temperatures.

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