Waste heat recycling system

Claim 1

Heat recycling apparatus for hot air dryers of the type having a pre-dryer section followed by a main dryer section each of which comprises a hollow insulated chamber through which product to be dried is carried along a path by a moving conveyor, the improvement comprising: a chamber for receiving fresh air to be introduced into the dryer, said chamber including baffle means for directing the fresh air from an air inlet to an air outlet through a circuitous multi-pass route within said chamber, a plurality of vertically positioned hot exhaust tubes within said chamber and exposed in said circuitous route, said hot exhaust tubes having inlet and outlet ends, said tube outlet ends being adjacent said fresh air inlet, said vertically positioned hot exhaust tubes including modular sections of tubes each modular section being mounted independent of the next whereby sections can be replaced as modules, said tubes including headers having cleaning spray nozzles directed upwardly and downwardly into said tubes for cleaning the interior of the tubes, means for forcing the fresh air along said route and into said pre-dryer section for extracting heat from the exhaust gases and increasing the temperature of the pre-dryer section so as to preheat the product to reduce time in the main dryer section, means for forcing hot exhaust from said main dryer section through said tubes for heating the fresh air prior to entering the pre-dryer section.