Heat exchanger tube having improved heat conductivity characteristics

Abstract

The present invention relates to a two-component heat exchanger tube ( 1 ) for producing heat exchangers. In particular, the tube ( 1 ) is of the two-component type comprising at least one inner component ( 10 ) and at least one outer component ( 20 ). Both components are made of metallic material. The inner component ( 10 ) is tubular in shape and comprises at least one outermost surface ( 11 ) and at least one innermost surface ( 12 ), where the latter defines a longitudinal cavity for the passage of a first fluid. The outer component ( 20 ) comprises a base surface ( 21 B) at which it is connected to the inner component ( 10 ). According to the invention, a layer ( 5 ) comprising graphene in pure form or in derivative form is provided between the outermost surface ( 11 ) of the inner component ( 10 ) and the base surface ( 21 B) of the outer component ( 20 ).

1 - 25 . (canceled) 
     
     
         26 . A two-component heat exchanger tube comprising:
 at least one inner component made of metallic material in the form of a tube comprising at least one outermost surface and at least one innermost surface, wherein the at least one innermost surface defines a longitudinal cavity for passage of a first fluid; and   at least one outer component made of metallic material comprising a base surface at which the at least one outer component is mechanically connected to the at least one inner component, the at least one outer component being configured for a second fluid to flow over externally,   wherein the base surface extends around the at least one outermost surface of the at least one inner component,   wherein a layer comprising graphene in pure form or in derivative form is provided between the at least one outermost surface of the at least one inner component and the base surface of the at least one outer component.   
     
     
         27 . The tube of  claim 26 , wherein the at least one outer component is configured to define at least one heat exchange fin over which the second fluid flows, the at least one fin extending around the at least one inner component. 
     
     
         28 . The tube of  claim 27 , wherein:
 the at least one outer component is configured to define a plurality of fins which extend around the at least one inner component according to a spiral profile considered in a longitudinal section plane containing a longitudinal axis of the at least one inner component, and   the fins have a circular shape considered in a transverse plane orthogonal to the longitudinal axis.   
     
     
         29 . The tube of  claim 28 , wherein:
 the at least one outer component is defined by a tubular body defining a cylindrical cavity, in which the at least one inner component of tubular shape is housed, and   the base surface of the at least one outer component delimits the cylindrical cavity.   
     
     
         30 . The tube of  claim 27 , comprising a plurality of outer components, each of the outer components respectively comprising a collar defining an inner surface at which it is mechanically connected to the outermost surface of the at least inner component, wherein each outer component defines a fin extending from and surrounding the collar, the outer components mechanically connected to the at least one inner component so as to be side by side longitudinally, wherein for each of the outer components a layer of graphene in pure or derivative form is provided between the inner surface of the collar and the at least one outermost surface of the at least one inner component. 
     
     
         31 . The tube of  claim 26 , wherein:
 the at least one outer component is defined by a strip made of metallic material mechanically applied to the at least one outermost surface of the at least one inner component at the base surface which is defined by an edge portion of the strip,   the strip is applied in a spiral pattern to define a plurality of fins extending around the at least one inner component, and   the layer comprising graphene in pure form or in derivative form is arranged between the at least one outermost surface of the at least one inner component and the base surface defined by the edge portion.   
     
     
         32 . The tube of  claim 31 , wherein:
 the edge portion is a longitudinal portion folded with respect to the body of the strip, whereby the fins, formed following spiral application of the strip around the at least one inner component, have a substantially L-shaped configuration, considered in a longitudinal sectional plane containing the longitudinal axis of the at least one inner component,   for each of the fins, considered on the section plane, a foot portion and a body portion are identified, wherein the foot portion is defined by a stretch of the edge portion of the strip, and   the layer comprising graphene is provided between at least a first side of the foot portion, facing the at least one inner component, and the at least one outermost surface of the at least one inner component.   
     
     
         33 . The tube of  claim 32 , wherein:
 for each of the fins, considered in the section plane, the foot portion comprises a first region and a second region,   the second region is included between the first region and a reminder of the strip,   the first and second regions configured to be offset wherein an inner side of the first region and an inner side of the second region are respectively adjacent to and spaced apart from the at least one outermost surface of the at least one inner component,   the second region of the foot portion overlaps with the first region of an adjacent fin,   the graphene layer being provided between the at least one outermost surface of the at least one inner component and the inner side of the first region of the foot portion.   
     
     
         34 . The tube of  claim 33 , wherein a further layer of graphene in pure or derivative form is provided between the overlapping regions of two adjacent fins. 
     
     
         35 . The tube of  claim 31 , wherein:
 the edge portion of the strip is inserted into a predefined spiral groove on the outer surface of the at least one inner component, and   the graphene layer is defined at least between the surfaces of the spiral groove and the edge portion of the strip inserted into the groove.   
     
     
         36 . The tube of  claim 31 , wherein a body of the strip is folded over itself so that two portions of the body are facing each other thereby defining a space inside which a further layer of graphene in pure form or in derivative form is provided. 
     
     
         37 . The tube of  claim 36 , wherein:
 the body of the strip is folded so that said two portions are facing each other according to a U-shaped configuration, and   the U-shaped configuration is further facing the outer surface of the base component.   
     
     
         38 . The tube of  claim 36 , wherein the body is folded such that the two portions are facing each other and connected such that the further layer is completely surrounded by the body of the strip. 
     
     
         39 . The tube of  claim 36 , wherein:
 the strip is folded such that the fins, defined following application of the strip onto the at least one inner component, have a substantially tuning fork configuration for which a base portion and a head portion are identified,   each of the base portion and the head portion are defined by two mutually facing portions of the strip, and   the further graphene layer is defined between the mutually facing portions of the strip defining the base portion.   
     
     
         40 . A method for producing an exchanger tube, the method comprising:
 (a) providing a first tubular body defining an inner component comprising at least one outermost surface and at least one innermost surface, wherein the at least one innermost surface defines a longitudinal cavity for passage of a first fluid, and further providing a second tubular body defining an outer component comprising a base surface, the outer component being configured for a second fluid to flow over externally;   (b) applying a layer comprising graphene in pure form or in derivative form to the at least one outermost surface of the inner component and/or to the base surface of the outer component;   (c) inserting the inner component into the outer component; and   (d) deforming the outer component to form a plurality of fins which extend around the inner component according to a spiral profile considered in a longitudinal section plane containing a longitudinal axis of the inner component, wherein the fins have a circular shape considered in a transverse plane orthogonal to the longitudinal axis, wherein the deformation is carried out by generating pressure on the outer component, following which the base surface thereof remains connected to the at least one outermost surface of the inner component.   
     
     
         41 . The method of  claim 40 , further comprising, before step (b), a step of cleaning the at least one outermost surface of the inner component and/or of the base surface of the outer component. 
     
     
         42 . The method of  claim 40 , wherein in said step (b) the graphene is dispersed in a liquid to be applied to the at least one outermost surface and/or to the base surface. 
     
     
         43 . The method of  claim 42 , wherein the dispersion is applied via a mechanical deposition technique, a deposition technique, or an electrochemical/electrophoretic deposition technique. 
     
     
         44 . The method of  claim 42 , wherein in said step (b) the graphene is applied in powder state onto the at least one outermost surface of the inner component and/or the base surface of the outer component. 
     
     
         45 . The method of  claim 40 , wherein step (d) comprises use of a lubricant containing graphite, wherein the lubricant is deposited onto the outer surface of the outer component during the generating of pressure and/or onto the fins formed following the generating of pressure. 
     
     
         46 . The method of  claim 40 , wherein step (d) is followed by a step of applying a further layer of graphene in pure form or in derivative form onto one or more regions of the surface of the outer component. 
     
     
         47 . A method for producing an exchanger tube, the method comprising:
 (a) providing a first tubular body made of metallic material defining an inner component, the inner component comprising at least one outermost surface and at least one innermost surface, wherein the at least one innermost surface defines a longitudinal cavity for passage of a first fluid;   (b) providing a strip made of metallic material defining an outer component, wherein the outer component comprises a base surface defined by an edge portion of the strip, the outer component being configured for a second fluid to flow over externally;   (c) folding an edge portion of the strip along a whole of its length in an L-shaped configuration;   (d) applying a layer comprising graphene in pure or derivative form onto the at least one outermost surface of the inner component and/or onto a side of the edge portion destined to be connected to the at least one outermost surface;   (e) mechanically connecting, in a spiral pattern, the edge portion of the strip to the at least one outermost surface of the inner component so that the layer comprising graphene remains placed between the first side of the edge portion and the outer surface of the inner component, wherein the strip is applied in a spiral pattern to define a plurality of fins extending around the at least one inner component.   
     
     
         48 . The method of  claim 47 , further comprising, before step (e), a step of knurling the at least one outermost surface of the inner component. 
     
     
         49 . The method of  claim 47 , further comprising a step of knurling the edge portion on a second side opposite the first side. 
     
     
         50 . A method for producing an exchanger tube, the method comprising:
 (a) providing a first tubular body made of metallic material defining an inner component, the inner component comprising at least one outermost surface and at least one innermost surface, wherein the at least one innermost surface defines a longitudinal cavity for passage of a first fluid;   (b) providing a strip made of metallic material defining an outer component, wherein the outer component is configured for a second fluid to flow thereover externally;   (c) forming a spiral groove on the at least one outermost surface of the inner component;   (d) depositing graphene in pure or derivative form in the spiral groove and/or in an edge portion of the strip destined to be inserted into the spiral groove;   (e) connecting the strip to the at least one outermost surface of the inner component by inserting the edge portion into the spiral groove and subsequently pressing edges of the spiral groove against opposing surfaces of the strip.