GAS HEATER HAVING FIREBOX WITH CONTROLLABLE OUTSIDE AIR MIXING VENT

摘要

A fireplace has a firebox with a controllable outside air vent to provide a source of cooler air for mixing with and modulating the temperature of the air heated by the fireplace. The air vent is vertically formed between a combustion chamber and a surrounding shell so that a convective current causes the air to flow therethrough and pass over the top surface of the combustion chamber to keep it cooler than otherwise possible with heated room air. Convective currents in another air duct formed between the shell and the combustion chamber circulates room air around the combustion chamber to transfer heat to the room air. The warmed outside air and room air mixes in a plenum above the fireplace prior to entering the room, thereby modulating the temperature of the heated air and permitting it to burn without excessively heating the room. A damper regulates the flow of outside air into the air vent, as desired.