Piping structure of cooling device, method for making the same, and method for connecting pipes

Abstract

In a piping structure of a cooling device using an ebullient cooling system, the cooling performance of the cooling device is degraded if the pipe is provided with flexibility, therefore, a piping structure of a cooling device according to an exemplary aspect of the invention includes a first tubular part with a hollow portion through which a refrigerant used in the cooling device flows; wherein the first tubular part is made of metal materials; and the surface roughness of the inner surface of the first tubular part is less than or equal to the size of a condensation nucleus for the refrigerant.

1 . A piping structure of cooling device, comprising:
 a first tubular part with a hollow portion through which a refrigerant used in the cooling device flows;   wherein the first tubular part is made of metal materials; and the surface roughness of the inner surface of the first tubular part is less than or equal to the size of a condensation nucleus for the refrigerant.   
     
     
         2 . The piping structure of cooling device according to  claim 1 ,
 wherein the first tubular part is formed through an annealing process.   
     
     
         3 . The piping structure of cooling device according to  claim 1 ,
 wherein the surface roughness of an inner surface of the first tubular part is equal to or more than 0.1 micrometers and less than or equal to 10 micrometers.   
     
     
         4 . The piping structure of cooling device according to  claim 1 ,
 wherein the thickness of the first tubular part is equal to or more than 0.4 mm and less than or equal to 1 mm.   
     
     
         5 . The piping structure of cooling device according to  claim 1 , comprising:
 the first tubular part; and   a second tubular part with which the first tubular part is covered,   wherein the second tubular part is made of organic materials.   
     
     
         6 . The piping structure of cooling device according to  claim 1 , further comprising:
 a first connection connected to an evaporator storing a refrigerant; and   a second connection connected to a condenser condensing and liquefying a vapor-state refrigerant vaporized in the evaporator and radiating heat.   
     
     
         7 . A cooling device, comprising:
 an evaporator storing a refrigerant;   a condenser condensing and liquefying a vapor-state refrigerant vaporized in the evaporator and radiating heat; and   a pipe connecting the evaporator to the condenser,   wherein the pipe comprises the a piping structure of cooling device, the piping structure of cooling device, comprising a first tubular part with a hollow portion through which a refrigerant used in the cooling device flows; wherein the first tubular part is made of metal materials; and the surface roughness of the inner surface of the first tubular part is less than or equal to the size of a condensation nucleus for the refrigerant.   
     
     
         8 . The cooling device according to  claim 7 ,
 wherein the evaporator comprises a first connective projection connected to the pipe;   the condenser comprises a second connective projection connected to the pipe; and   at least one of the first connective projection and the second connective projection is made of the same material as a metal material of which the first tubular part is made.   
     
     
         9 . A method for making a piping structure of cooling device, comprising the steps of:
 applying a rolling process to a metal material composing a hollow portion through which a refrigerant used in a cooling device flows;   forming a plate-like metal plate material with a surface roughness less than or equal to the size of a condensation nucleus for the refrigerant by the rolling process; and   bending the metal plate material into a tube and joining both ends.   
     
     
         10 . The method for making a piping structure of cooling device according to  claim 9 , further comprising:
 performing an annealing process subsequently to the joining process.   
     
     
         11 . The method for making a piping structure of cooling device according to  claim 9 , further comprising:
 forming a first tubular part made of metal materials by the joining process; and   covering the outer periphery of the first tubular part by ejecting an organic material and forming a second tubular part made of the organic material.   
     
     
         12 . A method for connecting pipes, comprising the steps of:
 fitting, in a connective projection, a pipe comprising a first tubular part, the first tubular part having a hollow portion through which a refrigerant used in a cooling device flowing, made of a metal material, and a surface roughness of its inner surface being less than or equal to the size of a condensation nucleus for the refrigerant;   applying a pressure from the outer periphery of the pipe toward the center; and   deforming the metal material composing the first tubular part by the pressure and attaching firmly the metal material to the connective projection.   
     
     
         13 . The method for connecting pipes according to  claim 12 ,
 wherein the first tubular part is formed through an annealing process.   
     
     
         14 . The method for connecting pipes according to  claim 12 ,
 wherein the pipe comprises a second tubular part, which is made of organic materials, with which the first tubular part is covered; and   the pressure is applied from the outer periphery of the second tubular part toward the center.