Patent ID: 8869878

Claim:
A flat plate heat pipe, comprising: a flattened hollow pipe section, formed by pressing a hollow pipe, the flattened pipe section providing a continuous surrounding wall unit, a first open end and a second open end, a chamber defined in the continuously surrounding wall for receiving a working fluid, the continuous surrounding wall unit having an upper plate, a lower plate facing the upper plate and two side plates continuously surrounding the chamber, wherein the first open end and the second open end are sealed and formed into a first sealing end and a second sealing end by diffusion bonding, wherein the chamber is sealed between the first sealing end and the second sealing end; a sintered middle layer disposed in the chamber, the sintered middle layer having a plurality of posts to stand between the upper plate and the lower plate of the flattened hollow pipe section, a plurality of separate horizontal extending elements, each of the plurality of posts having at least one horizontal extending element formed on a circumference of the post, the horizontal extending element extending horizontally and connecting with another post, wherein the plurality of posts and the plurality of separate horizontal extending elements are organized in a polygonal formation with a plurality of posts located separately at two opposite sides of the polygonal formation each separate post being connected to the polygonal formation by one horizontal extending element; and a wick structure layer coated on an internal surface of the upper plate and the lower plate of the wall unit facing the chamber, wherein the working fluid in the chamber flows through the wick structure layer; and wherein the posts have a top end and a bottom end being connected to the wick structure layer of the upper plate and the lower plate respectively and each horizontal extending element has a top side and a bottom side being connected to the wick structure layer of the upper plate and the lower plate respectively; and wherein the working fluid in the chamber flows through the sintered middle layer in both vertical and horizontal directions to increase the return path of the working fluid.