Plate-fin heat exchanger core design for improved manufacturing

Abstract

A method for producing a plate-fin heat exchanger core includes the steps of stacking a bottom end sheet, multiple alternately stacked individual hot and cold layers, and a top end sheet, each of the individual hot and cold layers including a fin element forming multiple parallel open-ended fluid channels, a parting sheet separating the various individual layers, and two closure bars positioned on opposite sides of the fin element, parallel to the open-ended channels and extending a length of the open-ended channels, brazing the bottom end sheet, the various layers, and the top end sheet in a brazing furnace; and removing material from each of the exterior faces by precision machining, thereby removing material from each closure bar outer face. The precision machining can include electrical discharge machining, laser cutting, band sawing, drilling, boring, hogging, acid etching, and ion milling, in any combination.

1 . A heat exchanger core comprising:
 a plurality of alternately stacked individual hot and cold layers having a parting sheet between adjacent hot and cold layers, each of the individual hot and cold layers including:
 a fin element forming a plurality of parallel open-ended channels adapted to pass a fluid therethrough, the open-ended channels of the individual hot layers parallel to each other, and the open-ended channels of the individual cold layers parallel to each other; and 
 two closure bars positioned on opposite sides of the fin element parallel to the open-ended channels and extending the length of the open-ended channels, 
 wherein each of the individual hot layers are aligned such that each of the individual hot layers facilitates airflow from a hot air inlet face of the heat exchanger to a hot air outlet face of the heat exchanger, and each of the individual cold layers are aligned such that each of the individual cold layers facilitates airflow from a cold air inlet face of the heat exchanger to a cold air outlet face of the heat exchanger; 
   hot core bands formed of the parting sheets and the closure bars of both the hot and cold layers, the hot core bands framing and extending from the hot air inlet face and from the hot air outlet face, the hot core bands configured to be welded to a hot air inlet manifold or to a hot air outlet manifold; and   cold core bands formed of the parting sheets and the closure bars of both the hot and cold layers, the cold core bands framing and extending from the cold air inlet face and from the cold air outlet face, the cold core bands configured to be welded to a cold air inlet manifold or to a cold air outlet manifold.   
     
     
         2 . The heat exchanger core of  claim 1 , wherein between adjacent hot core bands and cold core bands is a recessed region having a concave radius geometry configured to relieve temperature-induced material stress caused during a subsequent welding of the hot core bands to a hot air inlet manifold or to a hot air outlet manifold, and cold core bands to a cold core inlet manifold or to a cold core outlet manifold. 
     
     
         3 . The heat exchanger core of  claim 1 , further comprising:
 a top end sheet affixed on top of a top one of the plurality of alternately stacked individual hot and cold layers; and   a bottom end sheet affixed on bottom of a bottom one of the plurality of alternately stacked individual hot and cold layers.   
     
     
         4 . The heat exchanger core of  claim 1 , comprising one or more of nickel, aluminum, titanium, copper, iron, cobalt, and alloys thereof. 
     
     
         5 . The heat exchanger core of  claim 1 , wherein:
 the two hot closure bars of each of the individual hot and cold layers has a height between 0.025-2 in. (0.64-50.8 mm) and an original width.   
     
     
         6 . The heat exchanger core of  claim 1 , wherein the hot core bands and cold core bands are formed by precision machining of one or more of moving wire electrical discharge machining (EDM) and plunge EDM. 
     
     
         7 . The heat exchanger core of  claim 1 , wherein the hot core bands and cold core bands are formed by precision machining of one or more of laser cutting, band sawing, hogging, acid etching, and ion milling. 
     
     
         8 . A plate-fin heat exchanger comprising:
 the heat exchanger core of  claim 1 ;   a hot air inlet manifold welded to the hot core bands framing and extending from the hot air inlet face;   a hot air outlet manifold welded to the hot core bands framing and extending from the hot air outlet face;   a cold air inlet manifold welded to the cold core bands framing and extending from the cold air inlet face; and   a cold air outlet manifold welded to the cold core bands framing and extending from the cold air outlet face.   
     
     
         9 . The plate-fin heat exchanger of  claim 8 , wherein between adjacent hot core bands and cold core bands is a recessed region having a concave radius geometry configured to relieve temperature-induced material stress caused during a subsequent welding of the hot core bands to a hot air inlet manifold or to a hot air outlet manifold, and cold core bands to a cold core inlet manifold or to a cold core outlet manifold. 
     
     
         10 . The plate-fin heat exchanger of  claim 8 , further comprising:
 a top end sheet affixed on top of a top one of the plurality of alternately stacked individual hot and cold layers; and   a bottom end sheet affixed on bottom of a bottom one of the plurality of alternately stacked individual hot and cold layers.   
     
     
         11 . The plate-fin heat exchanger of  claim 8 , comprising one or more of nickel, aluminum, titanium, copper, iron, cobalt, and alloys thereof. 
     
     
         12 . The plate-fin heat exchanger of  claim 8 , wherein:
 the two hot closure bars of each of the individual hot and cold layers has a height between 0.025-2 in. (0.64-50.8 mm) and an original width.   
     
     
         13 . The plate-fin heat exchanger of  claim 8 , wherein the hot core bands and cold core bands are formed by precision machining of one or more of moving wire electrical discharge machining (EDM) and plunge EDM. 
     
     
         14 . The plate-fin heat exchanger of  claim 8 , wherein the hot core bands and cold core bands are formed by precision machining of one or more of laser cutting, band sawing, hogging, acid etching, and ion milling.