Patent ID: 7556088

Claim:
A heat exchanger assembly for cooling an electronic element comprising; a condensing tube defining a lower chamber for transferring heat from an electronic element to a working fluid to boil the working fluid and an upper chamber for transferring heat from the working fluid to the ambient air to condense the working fluid, said lower chamber extending between opposite ends and said upper chamber extending between and in fluid communication with said opposite ends of said lower chamber to define an endless loop, a plurality of internal fins extending within the endless loop of said tube for dissipating heat to the ambient air, and said internal fins presenting a plurality of V-shapes as viewed in cross-section with each fin extending transversly between and engaging both of said upper and lower chambers of said condensing tube whereby each fin transfers heat from the lower chamber to the upper chamber, and wherein said endless loop of said tube defines an oblong cross section extending from a center axis to reverse bends defining opposite ends, and wherein the axial length of the internal fins at the center axis is greater than the axial length of the internal fins at said ends.