Patent ID: 8561602

Claim:
A device using a natural draft to create a gas flame that swirls about a vertical axis, comprising: a base comprising: a stand having at least one support member defining an air passage in fluid communication with surrounding air, and a stand top defining an opening; a plenum comprising a plenum top, a plenum base, and at least one side, the plenum top, plenum base, and at least one side defining a plenum chamber having a first effective diameter, the plenum being mounted on the top of the stand with the plenum base engaging the opening in the top of the stand; wherein the plenum base defines a plurality of louvers or flaps that are disposed in the plenum base in a radial direction with respect to the vertical axis, with each louver or flaps defining a radial slit and a scoop depending from the plenum base along the length of the slit, establishing fluid communication between the stand opening and the plenum; wherein the plenum top defines an outlet centered on the vertical axis, the outlet having a second effective diameter that is no greater than the first effective diameter; a nozzle mix gas burner comprising a burner top, a bottom, and at least one side, the burner top, bottom, and at least one side defining a burner chamber having a third effective diameter and an outer surface with a perimeter, wherein the outer surface defines a plurality burner ports, each burner port having a central axis, with the burner ports angled so as to direct gas in a desired upward direction and a desired rotary direction with respect to the vertical axis; a gas inlet tube in fluid communication with the burner chamber, the gas inlet tube connectable to a source of gas fuel; wherein the third effective diameter is less than the first effective diameter, the burner is disposed within a lower portion of the plenum substantially centered on the vertical axis, leaving a desired portion of the plenum base exposed about the burner, and within which the plurality of louvers or flaps are disposed, with the plenum base further defining a passage adapted to receive the gas inlet tube; a chimney having a fourth effective diameter and defining a vertical flue having an upper end and a lower end, the lower end of the flue operably engaged with the plenum outlet and in fluid communication with the plenum chamber, the chimney being substantially centered on the vertical axis; wherein the scoops are inclined at such an angle, so that when air flows from the stand into the plenum via the louvers or flaps the air flow is angled in the same desired rotary direction as the gas flow along the central axis; and wherein the gas burner outer surface defines a plurality of upward projections, the upward projections comprising a plurality of stepped teeth disposed in a substantially circular manner about the perimeter of the gas burner outer surface, each of said stepped teeth having a rear incline and a front incline, and wherein the plurality of burner ports are defined in the front inclines of the stepped teeth.