Tunnel wick heat pipes

Claim 1

A method of fabricating a heat pipe with a sintered wick containing liquid flow tunnels comprising: providing a first non-bonding base fixture capable of retaining a longitudinal section of heat pipe casing and a vapor space mandrel oriented so that between them there is clearance space from the outer surface of the vapor space mandrel to the inner surface of the casing; providing retaining means within the clearance space between the vapor space mandrel and the casing to hold rods of the size of the desired liquid flow tunnels; placing a longitudinal section of heat pipe casing and a non-bonding vapor space mandrel into the first base fixture to form a clearance space in the shape of and equal to the desired thickness of the sintered metal wick; placing non-bonding rods, of size appropriate to define the desired liquid flow tunnels, into the retaining means in such a manner that the rods are oriented in that position in which the liquid flow tunnels are desired to be formed; filling the balance of the clearance space with powder capable of being sintered; heating the entire assembly of parts to a temperature, for a time, and in an atmosphere suitable for sintering the powder into a rigid wick structure; removing the rods from the assembly of parts leaving longitudinal tunnels with open ends in the wick structure; removing the vapor space mandrel from the assembly of parts; removing the casing with the sintered wick structure bonded to it from the first base fixture; and completing the assembly of the heat pipe with end caps and a closure tube by conventional heat pipe construction techniques and evacuating and filling the heat pipe with liquid by conventional methods.

Claim 2

A method of fabricating a heat pipe with a sintered wick containing liquid flow tunnels comprising: providing a first non-bonding base fixture capable of retaining a longitudinal section of heat pipe casing and a vapor space mandrel oriented so that between them there is clearance space from the outer surface of the vapor space mandrel to the inner surface of the casing; providing retaining means within the clearance space between the vapor space mandrel and the casing to hold rods of the size of the desired liquid flow tunnels; placing a longitudinal section of heat pipe casing and a non-bonding vapor space mandrel into the first base fixture to form a clearance space in the shape of and equal to the desired thickness of the sintered metal wick; placing non-bonding rods, of size appropriate to define the desired liquid flow tunnels, into the retaining means in such a manner that the rods are oriented in that position in which the liquid flow tunnels are desired to be formed; filling the balance of the clearance space with powder capable of being sintered; heating the entire assembly of parts to a temperature, for a time, and in an atmosphere suitable for sintering the powder into a rigid wick structure; removing the rods from the assembly of parts leaving longitudinal tunnels with open ends in the wick structure; removing the vapor space mandrel from the assembly of parts; removing the casing with the sintered wick structure bonded to it from the first base fixture; and completing the assembly of the heat pipe with end caps and a closure tube by conventional heat pipe construction techniques and evacuating and filling the heat pipe with liquid by conventional methods.

Claim 6

A method of making a heat pipe with active heat pipe sections connected by at least one conventional pipe comprising: partially encasing the ends of the pipe with sintering powder formed into a conventional wick configuration; forming liquid flow tunnels adjacent to the ends of the conventional pipe by placing non-bonding removable members within the sintering powder and protruding beyond the ends of the sintering powder to form liquid flow tunnels within the wick structure; sintering the powder into a rigid structure; and removing the removable members after the sintering operation.

Claim 7

A method of making a heat pipe with active heat pipe sections connected by at least one conventional pipe comprising: partially encasing the ends of the pipe with sintering powder formed into a conventional wick configuration; forming liquid flow tunnels adjacent to the ends of the conventional pipe by placing non-bonding removable members within the sintering powder and protruding beyond the ends of the sintering powder to form liquid flow tunnels within the wick structure; sintering the powder into a rigid structure; and removing the removable members after the sintering operation.