Device for heating air during the duty cycle of a combustion furnace

Abstract

An air heating device includes two closed conduits, one conduit for the flow of the air supply to a combustion furnace and the other for the flow of exhaust gas from a combustion furnace to a flue. The conduits pass through and around each other multiple times in an interweaving pattern such that the entirety of either conduit is almost completely surrounded by the other conduit, to maximize contact area and thermal energy transfer between the conduits relative to the device size and no use of small tubes or passageways. The shapes and pattern of the two conduits resembling the appearance of a sine wave and cosine wave drawn on the same x axis.

1 . A two closed conduit device comprising one conduit for the flow of the air supply to a combustion furnace and a second conduit for the flow of exhaust gas from a combustion furnace to a flue, wherein the conduits pass-through and around each other multiple times in an interweaving pattern such that the entirety of either conduit is substantially surrounded by the other conduit, to maximize contact area and thermal energy transfer between the conduits relative to the device size wherein the exhaust conduit does not use small tubes or passageways; further wherein the shapes and pattern of the first conduit resembling the appearance of a sine wave and the second conduit a cosine wave drawn wherein each wave is drawn on the same horizontal axis. 
     
     
         2 . The device of  claim 1 , wherein the widths of the vertical air conduit chambers progressively increase in the direction of the air flow and the widths of the vertical exhaust gas conduit chambers progressively decrease in the direction of the exhaust gas flow. 
     
     
         3 . The device of  claim 1 , wherein air guides are disposed on the inside walls of the vertical air and exhaust gas conduit chambers to increase thermal energy transfer between the air and exhaust gas flows and the conduit walls by increasing the surface area of the walls and the circulation of the air and exhaust gas against the walls. 
     
     
         4 . The device of  claim 1 , wherein each passing of the air and exhaust gas conduits through and around each other is enabled by a mesh style connection comprised of horizontal air ducts connecting two vertical air conduit chambers through a vertical exhaust gas conduit chamber without impeding the vertical flow of the exhaust gas through the chamber. 
     
     
         5 . The device of  claim 1 , wherein the efficiency of the thermal energy transfer from the exhaust gas flow to the air flow, relative to the size of the device, is of a level to make recycling of energy back to the furnace as preheated combustion air a mechanically and economically attractive energy saving technique. 
     
     
         6 . The device of  claim 1 , wherein pollutants are significantly filtered from the combustion exhaust gas flow before passing via the flue into the atmosphere, with filtered pollutants including particulate matter, sulfur, heavy metals, and other elements typically emitted by combustion furnaces fired by solid fuel or biomass. 
     
     
         7 . The device of  claim 1 , wherein the design of the exhaust gas conduit from a series of rectangular prism shaped chambers, without use of small tubes or passageways, enables easy cleaning access to the entire exhaust gas conduit interior via placement of narrow vertical doors along one side edge of each vertical exhaust gas conduit chamber.