Patent ID: 8387248

Claim:
A method of forming a heat exchanger comprising the steps of: a) forming a mandrel, the mandrel having opposite surfaces, b) forming apertures between the opposite surfaces of the mandrel and providing an association feature on the mandrel, forming grooves on the opposite surfaces of the mandrel, arranging the grooves on the opposite surfaces of the mandrel such that they intersect and forming the apertures within the mandrel where some or all of the grooves on the opposite surfaces of the mandrel intersect, c) providing a coating on the surface of the mandrel to provide a heat exchanger shell with an association feature, d) removing the mandrel from the heat exchanger shell to form a hollow heat exchanger shell, e) arranging a plurality of the hollow heat exchanger shells in a stack such that the association features are aligned, each hollow heat exchanger shell, formed in step d) has grooves on the opposite outside surfaces and a flow pattern on an inside surface, the grooves on the opposite outside surfaces of each hollow heat exchanger shell intersect and apertures extend through each hollow heat exchanger shell where some or all of the grooves on the opposite outside surfaces of the hollow heat exchanger shell intersect, f) consolidating the plurality of hollow heat exchanger shells in the stack to provide a heat exchanger with the association features of the hollow heat exchanger shells aligned, the hollow heat exchanger shells are aligned such that the grooves on the outside surfaces of the hollow heat exchanger shells provide flow channels between the hollow heat exchanger shells.