Heat exchanger tube with high heat transfer and low pressure drop

Abstract

A heat exchanger tube with outside diameter less than or equal to ten (10) inches and inside diameter greater than or equal to one-tenth (0.1) inches, comprising an inlet and an outlet; the heat exchanger tube enclosing and at least partly in contact with flow of a first fluid with the tube inner surface, separated from a second fluid at least partially in contact with the heat exchanger tube outer surface; one or a plurality of ridges disposed on the inner surface of the heat exchanger tube wall; a ridge having a height measured from the inner heat exchanger wall surface of less than or equal to one (1.0) millimeter.

What is claimed: 
     
         1 . A heat exchanger tube, comprising:
 an inlet and an outlet; and,   one or a plurality of ridges disposed on an inner surface.   
     
     
         2 . The heat exchanger tube of  claim 1  wherein the cross-section of at least one ridge has a circumference in the shape of approximately a circle, a semi-circle, a sector of a circle, a polygon, a trapezoid, an ellipse, a semi-ellipse, a sector of an ellipse, a polygon, a rectangle, a square, an oval, a triangle or a combination thereof. 
     
     
         3 . The heat exchanger tube of  claim 1  wherein at least one of said ridges has a spatial curve in the shape of approximately a spiral, a section of a spiral, a helix, a section of a helix, or a combination thereof. 
     
     
         4 . The heat exchanger tube of  claim 3  wherein at least one of said ridges has a spatial curve in the shape of approximately a spiral with elevation angle that changes along the length of said heat exchanger tube from about said inlet to about said outlet. 
     
     
         5 . The heat exchanger tube of  claim 3  wherein a ridge has a height less than or equal to approximately one (1) millimeter. 
     
     
         6 . The heat exchanger tube of  claim 3  wherein the ridge has a spiral angle less than or equal to approximately fifty (50) degrees and greater than or equal to approximately one (1) degree. 
     
     
         7 . A method for transferring heat between a first fluid and a second fluid, the method comprising:
 providing a heat exchanger tube according to  claim 1 ;   directing a first fluid into the inlet of said heat exchanger tube; and,   at least partially immersing said heat exchanger tube in a second fluid to transfer heat between the first fluid and the second fluid.   
     
     
         8 . The method for transferring heat between a first fluid and a second fluid of  claim 7 , wherein the first fluid comprises air, combustion gas, combustion byproducts, or a combination thereof. 
     
     
         9 . The method for transferring heat between a first fluid and a second fluid of  claim 7 , wherein the second fluid comprises water, steam, oil or a combination thereof. 
     
     
         10 . A method of manufacture of a heat exchanger tube of  claim 1 , wherein at least one of said ridges is disposed upon an inner surface of said heat exchanger tube and secured in least one region by a weld. 
     
     
         11 . A method of manufacture of a heat exchanger tube of  claim 1 , wherein at least one of said ridges is disposed upon an inner surface of said heat exchanger tube by etching said ridge on the surface of a plate and deforming said plate into the shape of a tube. 
     
     
         12 . A method of manufacture of a heat exchanger tube of  claim 1 , wherein at least one of said ridges is disposed upon an inner surface of said heat exchanger tube by embossing said ridge on the surface of a plate and deforming said plate into the shape of a tube. 
     
     
         13 . A method of manufacture of a heat exchanger tube of  claim 1 , wherein at least one of said ridges is disposed upon an inner surface of said heat exchanger tube and secured in least one region friction between the outer surface of said ridge and the inner surface of said heat exchanger tube. 
     
     
         14 . A method of manufacture of a heat exchanger tube of  claim 1 , wherein at least one of said ridges is manufactured an inner surface of said heat exchanger tube by cutting excess material from the inner surface of said heat exchanger tube to result in said ridge in relief. 
     
     
         15 . A heat exchanger tube, comprising:
 an inlet and an outlet;   one or a plurality of ridges disposed on an inner surface of the heat exchanger tube;   a ridge having a spatial curve in the shape of approximately a spiral, a section of a spiral, a helix, a section of a helix, or a combination thereof disposed on the inner surface;   the height of said ridge less than or equal to approximately one (1) millimeter; and,   said ridge having a spiral angle less than or approximately equal to fifty (50) degrees and greater than or approximately equal to one (1) degree.