Finned tube with indentations

Abstract

A tube used for heat transfer has adjacent fins extending from an outer surface of the tube with a channel between the fins. The fins include a roof formed over the channel, and holes penetrate the roof into the channel. The fin, including the roof, is monolithic with the tube body. Helical ridges are formed on a tube inner surface, and the tube body includes an indentation in the outer surface which extends the tube body inner surface towards a tube axis.

1 . A finned tube comprising:
 a tube body having an outer surface, an inner surface, and an axis;   at least one monolithic fin defined on the tube body outer surface such that, in the axial direction, the tube outer surface has adjacent fins, wherein a channel is defined between adjacent fins, and wherein the fin has an upper portion deformed to form a roof over the channel, and wherein the roof defines holes penetrating in to the channel;   a plurality of helical ridges defined on the tube body inner surface;   at least one helical indentation defined in the tube body outer surface such that the indentation extends the tube body inner surface towards the tube axis.   
   
   
       2 . A finned tube comprising:
 a tube body having an inner surface;   a helical ridge defined on the tube body inner surface; and   an indentation defined in the tube body, the indentation looping around the tube.   
   
   
       3 . The finned tube of  claim 2  wherein the indentation is helical, and wherein the indentation spirals around the tube in the opposite direction of the ridge. 
   
   
       4 . The finned tube of  claim 2  wherein the indentation is helical, and wherein the indentation spirals around the tube in the same direction as the ridge. 
   
   
       5 . The finned tube of  claim 2  wherein the indentation further comprises a plurality of indentations forming successive rings around the tube. 
   
   
       6 . The finned tube of  claim 2  wherein the indentation further comprises a plurality of helical indentations spiraling around the tube body in opposite directions. 
   
   
       7 . The finned tube of  claim 2  wherein the tube body includes an outer surface, the finned tube further comprising a monolithic helical fin defined on the tube body outer surface such that the tube body outer surface includes adjacent fins when viewed axially, wherein a channel is defined between adjacent fins, and wherein the fin includes an upper portion deformed to form a roof over the channel. 
   
   
       8 . The finned tube of  claim 7  wherein the tube body outer surface, adjacent fins, and the roof define a boiling cavity, and wherein the roof defines a plurality of roof holes penetrating into the boiling cavity. 
   
   
       9 . The finned tube of  claim 8  wherein the fins include a fin top having notches, and the notches define the roof holes. 
   
   
       10 . The finned tube of  claim 2  wherein the tube is comprised of copper. 
   
   
       11 . A finned tube comprising:
 a tube body having an outer surface;   a monolithic fin defined on the outer surface such that the outer surface includes adjacent fins viewed in the axial direction, wherein a channel is defined between adjacent fins, and wherein the fins include an upper portion deformed into a roof over the channel; and   an indentation defined in the tube body, the indentation looping around the tube.   
   
   
       12 . The finned tube of  claim 11  wherein the indentation is helical. 
   
   
       13 . The finned tube of  claim 11  wherein the indentation further comprises a plurality of helical indentations spiraling around the tube in opposite directions. 
   
   
       14 . The finned tube of  claim 11  wherein the indentation further comprises a plurality of indentations forming successive rings around the tube body. 
   
   
       15 . The finned tube of  claim 11  wherein the tube body further includes an inner surface, the finned tube further comprising a helical ridge defined on the tube body inner surface. 
   
   
       16 . The finned tube of  claim 15  wherein the indentation is helical and the indentation spirals around the tube in the opposite direction as the ridge. 
   
   
       17 . The finned tube of  claim 15  wherein the indentation is helical and the indentation spirals around the tube in the same direction as the ridge. 
   
   
       18 . The finned tube of  claim 15  wherein the tube body outer surface, adjacent fins, and the roof define a boiling cavity, and the roof defines a plurality of holes penetrating into the boiling cavity. 
   
   
       19 . The finned tube of  claim 18  wherein the indentation interrupts the boiling cavity. 
   
   
       20 . The finned tube of  claim 11  wherein the tube is comprised of copper.