Heat pipe ring stacked assembly

Abstract

A heat pipe ring for use in a crystal growth furnace is ring-shaped with at least one arm thereon and is constructed as one piece. An RF coil for heating a working fluid in said heat pipe is attached about said arm or an electric current can flow from one arm to an oppositely located arm to heat said body. These rings can be stacked and each may have an independently controlled sources of heat. Each heat pipe ring of the present invention has a wall of three layers of refractory material. In the case of working above 1000.degree. C., the working fluid can be lithium and the wall made of a layer of tungsten, a layer of graphite as a spacer, and a layer of silicon carbide. The internal surface on the tungsten layer is knurled to support capillary action. As a result of these features the heat pipe ring is able to survive high temperatures, greater than 1000.degree. C., high pressures, greater than 80 atm, corrosive atmospheres, a high vacuum, and further provides azimuthal symmetry as well as axial temperature gradient profiles when the heat pipes are stacked and independently heated.