Abstract: A heater including a fire enclosure, such as a fireplace, has side walls each of which includes spaced walls which define a passageway for circulation of room air and is provided with recesses adjacent to the fire enclosure and extending into the room air passageways. In a preferred embodiment, the fire enclosure doors are mounted in the compartments and are provided with a unique mounting and handle by which a particular door may be selected and moved to a closed position in front of the fire enclosure opening.

Abstract: A method and apparatus produces an unrestrained vortical fluid flow pattern which is self limiting in diameter and remains stable in persistence throughout varying conditions of velocity, density, and temperature of the fluid.

Abstract: A set of fireplace andirons are slidable with respect to the fuel (log) supports. The unit may be formed integrally with a fireplace structure or as a separate distinct assembly. The sliding anvils may support other elements, such as a cooking grill.

Abstract: A fireplace unit wherein room air is circulated under the firebox bed plate has an ash discharge chute which depends from the rear portion of the bed plate and registers with the conventional fireplace ash chute. The ash chute includes diametrically opposite openings in the respective front and rear walls which openings communicate with the room air passageway under the bed plate and permit flow of recirculating room air transversely through the ash chute.

Abstract: A flow controller is constructed to induce a stable unrestrained vorticity pattern in a position where its circumferential expansion into the flow path acts as a self-adjusting impedance to the flow. The controller finds particularly advantageous utility in a furnace, stove, or fireplace.

Abstract: A heat exchanger particularly for use in a circulating hot air fireplace is constructed to induce vorticity in the flame and/or hot combustion gases at a position in proximity to a heat exchange surface to enhance residence time and thermal transfer to the circulating air.The vorticity pattern acts as a self-adjusting flow controller.

Abstract: A heat exchanger particularly for use in a circulating hot air fireplace is constructed to induce vorticity in the flame and/or hot combustion gases at a position in proximity to a heat exchange surface to enhance residence time and thermal transfer to the circulating air.The vorticity pattern acts as a self-adjusting flow controller.