Heat-exchange pipe and producing method thereof

Abstract

A heat-exchange pipe that is excellent in heat-exchange property in which a metal porous body is not easily dropped off form a metal pipe; which is provided with the metal pipe and the metal porous body made by joining a plurality of metal fibers bonded to an inner-wall surface of the metal pipe; at least some of the metal fibers in the metal porous body are partially bonded to the inner-wall surface of the metal pipe along a length direction, bended on the inner-wall surface of the metal pipe, and extend to leave from the inner-wall surface.

1 . A heat-exchange pipe comprising
 a metal pipe having a circular cross section and   a metal porous body which is configured by joining a plurality of metal fibers and bonded to an inner-wall surface of the metal pipe, wherein   at least some of the metal fibers are partially bonded to the inner-wall surface of the metal pipe for a length direction, and the metal fibers which are bonded to the inner-wall surface bend on the inner-wall surface of the metal pipe and extend from the inner-wall surface to leave.   
     
     
         2 . The heat-exchange pipe according to  claim 1 , wherein a bonding area ratio of the metal fibers to the inner-wall surface of the metal pipe is 5% or more. 
     
     
         3 . The heat-exchange pipe according to  claim 1 , wherein in a transverse cross section across an axis of the metal pipe, a difference between an average area ratio of the metal fibers in a center circle part corresponding a half of an area of the metal porous body and an average area ratio of the metal fibers in a whole of the transverse cross section is 5% or less. 
     
     
         4 . A producing method of a heat-exchange pipe, comprising
 a precursor formation step of stacking a plurality of metal fibers to form a precursor,   an in-pipe charging step of pushing the precursor from one end of a metal pipe to charge into the metal pipe, and   a sintering step of sintering the metal pipe in a state of charging the precursor, wherein   the precursor before the in-pipe charging step is formed such that an outer diameter in a state where the metal fibers are stacked is larger than an inner diameter of the metal pipe.   
     
     
         5 . The heat-exchange pipe according to  claim 2 , wherein in a transverse cross section across an axis of the metal pipe, a difference between an average area ratio of the metal fibers in a center circle part corresponding a half of an area of the metal porous body and an average area ratio of the metal fibers in a whole of the transverse cross section is 5% or less. 
     
     
         6 . The heat-exchange pipe according to  claim 1  wherein the metal porous body further includes metal powder particles bonded to the metal fibers. 
     
     
         7 . A heat-exchange pipe comprising
 a metal pipe, and   a porous body which is configured by sintering a plurality of metal base substances and bonded to an inner-wall surface of the metal pipe, wherein   the metal base substances includes metal fibers, and the metal fibers bonded to the inner-wall surface partially leave from the inner-wall surface.   
     
     
         8 . The heat-exchange pipe according to  claim 7  wherein the metal base substances further include metal powder particles. 
     
     
         9 . The heat-exchange pipe according to  claim 8  wherein a ratio of the metal powder particles in the metal base substances is 15% by mass or less. 
     
     
         10 . The heat-exchange pipe according to  claim 8  wherein a particle diameter of the metal powder particles is 5 μm or more and 500 μm or less. 
     
     
         11 . The heat-exchange pipe according to  claim 7  wherein the metal base substances are made of aluminum or aluminum alloy, and are joined by a base substance joint part contains a eutectic-element compound including eutectic element that eutectic-reactions with Ti—Al type compounds and Al. 
     
     
         12 . The heat-exchange pipe according to  claim 7 , wherein a ratio L/R between a length L and a fiber diameter R of the metal fibers I 10 or more and 500 or less.