Heat exchanger with partial-height folded fins

Abstract

A heat exchanger has a plurality of plates having opposed surfaces and side walls extending beyond the opposed surfaces to a height (h); and a fin pack extending from one opposed surface toward an opposed surface of an adjacent plate, and having a fin height (f), wherein the fin height (f) is equal to or less than the height (h). The plates can be stacked to form a heat exchanger assembly with a gap between adjacent fin packs.

1 . A heat exchanger, comprising:
 a plurality of plates having opposed surfaces and side walls extending beyond the opposed surfaces to a height (h);   a fin pack extending from one opposed surface toward an opposed surface of an adjacent plate, and having a fin height (f), wherein the fin height (f) is equal to or less than the height (h).   
     
     
         2 . The heat exchanger of  claim 1 , further comprising a second fin pack having a height (h) and extending from the opposed surface of the adjacent plate toward the one opposed surface and having a fin height (f) that is less than or equal to the height (h). 
     
     
         3 . The heat exchanger of  claim 2 , wherein a gap is defined between the fin pack and the second fin pack. 
     
     
         4 . The heat exchanger of  claim 3 , wherein the fin packs are a folded structure, and wherein the gap is defined between crests of the folded structure. 
     
     
         5 . The heat exchanger of  claim 4 , wherein the gap is less than or equal to 0.020 inches (0.508 mm). 
     
     
         6 . The heat exchanger of  claim 1 , wherein the plurality of plates are stacked with side walls of adjacent plates bonded to each other. 
     
     
         7 . The heat exchanger of  claim 1 , wherein the plurality of plates define an internal flow passage. 
     
     
         8 . The heat exchanger of  claim 1 , wherein the opposed surfaces of adjacent plates of the plurality of plates define an external flow passage, and wherein the fin pack comprises two fin packs in the external flow passage, with one of the two fin packs extending from each of the opposed surfaces toward the other of the two fin packs. 
     
     
         9 . The heat exchanger of  claim 1 , wherein the fin pack is diffusion bonded or brazed to one of the opposed surfaces. 
     
     
         10 . A heat exchanger subassembly, comprising:
 a plate having first and second opposed surface, and side walls extending transverse to the opposed surfaces to define a side wall height (h) relative to the opposed surfaces;   at least one internal flow passage defined in the plate; and   a first folded fin pack on the first opposed surface and a second folded fin pack on the second opposed surface, each folded fin pack having a fin height (f) that is less than or equal to the side wall height (h).   
     
     
         11 . The heat exchanger subassembly of  claim 10 , wherein the internal flow passage extends substantially transverse to flow passages defined along walls of the first folded fin pack and the second folded fin pack. 
     
     
         12 . The heat exchanger subassembly of  claim 10 , wherein the first folded fin pack and the second folded fin pack are bonded to the first and second opposed surfaces. 
     
     
         13 . A method for making a heat exchanger, comprising:
 bonding a first folded fin pack and a second folded fin pack to opposed surfaces of a plate having side walls and an internal flow passage to form a heat exchanger subassembly;   stacking the heat exchanger subassembly with a further heat exchanger subassembly with a gap defined between adjacent folded fin packs; and   bonding the heat exchanger subassembly to the further heat exchanger subassembly at contacting surfaces of the side wall of each heat exchanger subassembly.   
     
     
         14 . The method of  claim 13 , wherein the bonding step comprises diffusion bonding. 
     
     
         15 . The method of  claim 13 , wherein the bonding step comprises brazing. 
     
     
         16 . The method of  claim 13 , wherein the side walls extend beyond the opposed surfaces to a height (h), and wherein the fin pack has a fin height (f), wherein the fin height (f) is equal to or less than the height (h).