Patent ID: 7360534

Claim:
Apparatus for supplying heated replacement air to a process in which air is exhausted, said apparatus comprising an air intake connected to an injection chamber from which a desired volume of replacement air flows to the process, a source of BTU energy positioned outside said injection chamber and configured to inject heated gas into said injection chamber; at least one process fan configured to: i) draw replacement air through said air intake and into said injection chamber, and ii) deliver a predetermined and adjustable volume of the heated replacement air to the process, wherein the volume of the heated replacement air does not affect the products of combustion of the BTU energy that is injected; and, an adjustable mode changing damper configured to be movable between a first position wherein replacement air from a first location is drawn by said at least one fan from said air intake into said injection chamber and a second position wherein air from a second location is drawn by said at least one fan into said injection chamber.