Duct

Abstract

The present invention relates to a duct for conducting a flowing primary fluid, having a thermally conductive wall with exterior ribs having an exterior side through which a secondary fluid can pass, at least partially, whereby the duct wall comprises a structured surface on its exterior side in addition to the ribs. The invention further relates to a heat exchanger with an inventive duct and an air condenser, particularly a natural-draught condenser, with inventive heat exchangers.

1 . Duct ( 2 ) for conducting a flowing primary fluid, having a thermally conductive wall ( 3 ) with exterior ribs ( 8 ,  9 ) having an exterior side through which a secondary fluid can pass, at least partially, characterized in that the ribs ( 8 ,  9 ) have a structured surface ( 17 ), at least in part.  
   
   
       2 . Duct according to  claim 1 , characterized in that the ribs ( 8 ,  9 ) have a fully structured surface ( 17 ).  
   
   
       3 . Duct according to  claim 1 , characterized in that the structured surface ( 17 ) comprises formations ( 18 ).  
   
   
       4 . Duct according to  claim 1 , characterized in that the structured surface ( 17 ) comprises depressions ( 19 ).  
   
   
       5 . Duct according to  claim 1 , characterized in that the structured surface ( 17 ) is aligned with a flow direction of the secondary fluid such that formations ( 18 ) and depressions ( 19 ) are arranged in alternation in the flow direction.  
   
   
       6 . Duct according to  claim 1 , characterized in that the formations ( 18 ) and/or depressions ( 19 ) form a uniform pattern.  
   
   
       7 . Duct according to  claim 1 , characterized in that the structured surface ( 17 ) has a microstructure ( 21 ) and/or a macrostructure ( 22 ).  
   
   
       8 . Duct according to  claim 1 , characterized in that the size of the formation ( 18 ) and/or the depression ( 19 ) of the macrostructure ( 22 ) in the direction of the secondary fluid flow equals a few tenths of a millimeter, in particular 0.30 mm to 1.00 mm.  
   
   
       9 . Duct according to  claim 1 , characterized in that the size of the formation ( 18 ) and/or the depression ( 19 ) of the microstructure ( 21 ) in the direction of the secondary fluid flow equals a few hundredths of a millimeter, in particular 0.05 mm to 0.15 mm.  
   
   
       10 . Duct according to  claim 1 , characterized in that a plurality of ribs is formed by a corrugated rib strip ( 8 ,  9 ).  
   
   
       11 . Duct according to  claim 1 , characterized in that the corrugated rib strip ( 8 ,  9 ) extends in the longitudinal direction of the duct ( 2 ).  
   
   
       12 . Duct according to  claim 1 , characterized in that the corrugated rib strip ( 8 ,  9 ) is covered by a plate ( 11 ,  12 ) on its side facing away from the duct wall ( 3 ), and forms a meander structure ( 15 ,  16 ) through which the secondary fluid can pass.  
   
   
       13 . Duct according to  claim 1 , characterized in that the corrugated rib strip ( 8 ,  9 ) is soldered and/or glued at its turning points ( 10 ,  13 ) to the duct wall ( 3 ) and the plate ( 11 ,  12 ).  
   
   
       14 . Heat exchanger ( 1 ) having at least one duct ( 2 ) according to  claim 1 .  
   
   
       15 . Heat exchanger according to  claim 14 , characterized in that the heat exchanger comprises a duct ( 2 ) with a passable meander structure ( 15 ,  16 ) having exterior coverplates ( 11 ,  12 ) which form a stackable duct configuration.  
   
   
       16 . Heat exchanger according to  claim 14 , characterized in that the heat exchanger comprises a plurality of stacked plate-shaped duct configurations, whereby different fluids in alternation can pass through adjoining plate-shaped duct configurations.  
   
   
       17 . Air condenser for condensing steam, particularly turbine steam of a power plant, whereby steam that is to be condensed can be fed to heat exchangers ( 1 ) by way of a steam supply line and partitions, and whereby lines are provided for condensate removal and inert gas discharge, characterized in that at least one heat exchanger ( 1 ) is a heat exchanger according to one of the preceding claims  14  through  16 .  
   
   
       18 . Air condenser according to  claim 17 , characterized in that the air condenser is a natural-draught condenser.