Maple syrup vaporizer apparatus with hollow shell recirculation arch

摘要

A hollow shell recirculation arch underlies and supports at least one maple sap vaporizing pan. The arch is formed of inner and outer sheet metal shells. The inner shell is upwardly open and is sized smaller than the outer shell so as to form a space therebetween defining a first head exchange chamber. A transverse bridge wall is interposed within the inner shell, intermediate of the inner shell front wall and a rear wall, and separating the inner shell into a fire box and a second heat exchange chamber. Fire brick lines the interior surfaces of the fire box. Preferably the transverse sidewalls of the inner shell are V-shaped to concentrate and reflect the heat upwardly through the open top of the inner shell against the vaporizing pan. A smoke stack assembly includes a horizontal smoke stack pipe fixedly mounted to the arch and projecting through the rear walls of the outer and inner shells and extending over the major length of the regenerative head exchanger section of the arch and terminates in an open end facing the bridge wall and spaced slightly therefrom. Fresh combustion air is forced through the first head exchange chamber between the inner and outer shells, flowing the length of the arch for preheating the combustion air. Passages provide a primary air stream feed into the combustion chamber along with secondary air through the bridge wall which is preferably hollow and bears a plurality of short length nozzles discharging secondary air into the fire box.