A Heat Pipe is a passive heat transfer device with an extremely high effective thermal conductivity. Its two-phase heat transfer mechanism results in heat transfer capabilities from one hundred to several thousand times that of an equivalent piece of copper.
A heat pipe consists of a vacuum tight envelope, a wick structure and a working fluid. The heat pipe is evacuated and then back-filled with a small quantity of working fluid, just enough to saturate the wick. The atmosphere inside the heat pipe is set by an equilibrium of liquid and vapour. As heat enters at the evaporator, this equilibrium is upset generating vapour at a slightly higher pressure. This higher pressure vapour travels to the condenser end where the slightly lower temperatures cause the vapour to condense giving up its latent heat of vaporization. The condensed fluid is then pumped back to the evaporator by the capillary forces developed in the wick structure.
This continuous cycle transfers large quantities of heat with very low thermal gradients. A heat pipes operation is passive being driven only by the heat that is transferred. This passive operation results in high reliability and long life.
Flat Heat Pipes – HPF Series
By using a flat heat pipe it may be possible to eliminate a costly fan and heat sink, with the additional benefits of reducing power consumption, noise output, product thickness and cost. Flat heat pipes can directly remove heat from the source transferring it directly to the chassis or to an external heat sink. It also negates the need for ventilation holes and so reduces ingress of dust (no air filters required) and static. The thickness of the HPF series ranges from 1.2mm to 2.5mm, across widths from 20mm – 50mm. Lengths range from 60mm~500mm. The HPF series Flat Heat Pipes can achieve up to 270W of heat load transfer.