Maple syrup vaporizer apparatus with hollow shell recirculation arch

A maple syrup vaporizer apparatus comprising a vaporizing pan assembly, a hollow shell recirculation arch underlying and supporting said vaporizing pan assembly and being sealably coupled thereto said hollow shell recirculation arch comprising an outer sheet metal shell including laterally spaced vertical sidewalls, longitudinally spaced vertical front and rear walls, and a bottom wall edge coupled at opposite ends to said front wall and rear wall, respectively and laterally edge coupled to respective lateral sidewalls, an inner shell upwardly open within said outer shell defined by at least laterally opposed sidewalls and a front wall and a rear wall at opposite ends thereof, said inner shell being sized such that at least over a portion of its width and length, it forms with said outer shell a first heat exchange chamber therebetween a bridge wall interposed within said inner shell, intermediate of said inner shell front wall and rear wall and forming, with said inner shell front wall a fire box, and with said rear wall of said inner shell, a second heat exchange chamber, said first and second heat exchange chamber defining a regenerative heat exchanger, an insulated deck extending horizontally over the major portion of the length of the second heat exchange chamber having a front edge sealed to said bridge wall and a rear edge spaced from the vertical rear wall of said inner shell, brickwork lining the interior surfaces of the fire box, the fire box being open at the top and directly facing the bottom of the pan assembly, and wherein means are provided within at least one of said hollow shell regeneration arch and said pan assembly for forming a horizontal passage from said fire box to the rear edge of the insulated deck for permitting products of combustion to flow from the fire box between the insulated deck and the bottom of the pan assembly and for entering the second regenerative heat exchange chamber by reverse flow about the rear edge of the insulated deck, and a smoke stack assembly including a horizontal smoke stack pipe fixedly mounted to the arch, projecting through the rear wall of the outer shell and the rear wall of the inner shell, and extending over the major length of the regenerative heat exchanger section of the arch and having an open end facing the bridge wall and spaced slightly therefrom, and means for forcing fresh combustion air into the first regenerative heat exchange chamber between the inner and outer shells for flowing the length of the arch, for preheating of the combustion air and means for discharging preheated combustion air as a primary air stream into the fire box for facilitating the combustion of fuel within the fire box in contact with the preheated fresh combustion air.