Patent ID: 7743821

Claim:
A heat exchanger comprising: at least one tube defined by a peripheral tube wall for circulating a first fluid; a single continuous fin spirally wound about and attached directly to said at least one tube and being in heat exchange relation between the fluid flowing in said at least one tube and a second fluid flowing about the fin and said at least one tube; said single continuous fin having a substantially smooth, flat surface with at least one groove formed within said substantially smooth, flat surface of said single continuous fin, spaced radially outwardly of said peripheral tube wall and spaced radially inwardly an outer peripheral edge of said substantially smooth flat surface, said groove extending continuously along said single continuous fin to generate fluid vortices for heat transfer enhancement with minimum pressure loss as compared with a smooth undeformed fin wherein said at least one groove forms a projection extending outwardly of said substantially smooth flat surface on one side of said single continuous fin in a registration with a concave recess formed by said groove in an opposite side of said single continuous fin in an axially adjacent portion thereof.