Patent ID: 7147050

Claim:
A heat exchanger foil apparatus comprising: a first manifold zone comprising generally uniform foil corrugations of a reduced height; and a primary surface zone including: a central portion comprising generally uniform foil corrugations of a full height; and a first transition zone located between said central portion and said first manifold zone, said first transition zone having foil corrugations of heights less than said full height and greater than said reduced height, wherein, the height of each of a plurality of the foil corrugations of the first transition zone is approximately said reduced height where the corrugation is adjacent said first manifold zone and is approximately said full height where the corrugation is adjacent said central portion, and wherein, at least one of a said plurality of the foil corrugations has an aspect ratio that varies along a portion of its length between said first manifold zone and said central portion, said aspect ratio being defined as rise over run.