CIRCULAR HEAT EXCHANGER

Circular heat exchangers have been used to increase the efficiency of engines by absorbing heat from the exhaust gases and transferring a portion of the exhaust heat to the intake air. The present heat exchanger is built-up from a plurality of preformed involute curved cells stacked in a circular array to provide flow passages and for the donor fluid and the recipient fluid respectively. The stacked cells are welded along a portion of their edges to secure them in the stacked circular array. Each of the cells have a plurality of corners with the core presenting corresponding corners after the cells are welded together. In order to reinforce the core against thermal stresses and forces generated by pressures of the fluids, circumferential welds are provided at each of the corners.