High temperature primary surface recuperator air cell

Abstract

Primary surface recuperators generally undergo severe thermal and pressure cycles. Thermal cycling tends to cause the primary surface recuperator to expand along a central axis. However ducting connected with the primary surface recuperator tends to limit its expansion. Constructing bars in cells of the primary surface recuperator from the same material as the ducting tends to reduce thermal stresses that may otherwise result from difference in thermal expansion.

What is claimed is:  
     
         1 . A cell for use in a primary surface recuperator, said cell comprising: 
 a first sheet being made from a first material;    a second sheet having generally equivalent dimensions as said first sheet, said second sheet being made from said first material; and    an air bar being attached between said first sheet and said second sheet, said bar being made from a second material;    wherein said second material has a lower coefficient of thermal expansion than said first material.    
     
     
         2 . The cell for use in said recuperator as described in  claim 1  wherein said second material is a nickel based alloy.  
     
     
         3 . The cell for use in said recuperator as described in  claim 1  wherein said air bar being proximate an air outlet duct.  
     
     
         4 . The cell for use in said recuperator as described in  claim 1  including a second air bar attached between said first sheet and said second sheet.  
     
     
         5 . The cell for use with said recuperator as described in  claim 4  wherein said second air bar being made of said first material.  
     
     
         6 . The cell for use with said recuperator as described in  claim 5  wherein said second air bar being made of said second material.  
     
     
         7 . The cell for use with said recuperator as described in  claim 1  wherein said air bar further comprises a duct tab portion, said duct tab portion is adapted for connection with said air outlet duct.  
     
     
         8 . A recuperator comprising: 
 a plurality of cells, each of said plurality of cells comprising a first sheet, a second sheet, said first sheet and said second sheet having generally equivalent dimensions, said first sheet and said second sheet being made of a first material, a bar separating said first sheet from said second sheet, said air bar being made from a second material; and    a duct being connected with said plurality of cells about said bar, said duct being made of said second material.    
     
     
         9 . The recuperator as described in  claim 8  wherein said second material is a nickel based alloy.  
     
     
         10 . The cell for use in said recuperator as described in  claim 8  wherein said air bar being proximate said air outlet duct.  
     
     
         11 . The cell for use in said recuperator as described in  claim 8  including a second air bar attached between said first sheet and said second sheet.  
     
     
         12 . The cell for use with said recuperator as described in  claim 11  wherein said second air bar being made of said first material.  
     
     
         13 . The cell for use with said recuperator as described in  claim 11  wherein said second air bar being made of said second material.