Plate heat exchanger with enhanced surface features

Abstract

A plate heat exchanger includes a plurality of plates for providing a flow path for two fluids. The plate heat exchanger has an inlet and an outlet for each of the two fluids, wherein facing surfaces of two adjacent plates of the plurality of plates defines a flow path for a first fluid. The opposite surface of one of the two adjacent plates and a facing surface of another adjacent plate from the plurality of plates provides a flow path for a second fluid. The first fluid and the second fluid flowing along their respective flow paths are maintained in thermal communication with each other. A plurality of surface features associated with at least a portion of one surface of at least one of the plates provides enhanced heat transfer between the two fluids passing along adjacent plates.

1 . A plate heat exchanger comprising: 
 a plurality of plates, each plate having opposed nonplanar surfaces and perimeter flanges, for providing at least one flow path for each of at least two fluids, wherein facing surfaces and perimeter flanges of a pair of adjacent plates of the plurality of plates define a flow path for each fluid of the at least two fluids, and wherein opposed surfaces of at least one plate of each pair of adjacent plates provides a flow path boundary for two fluids of the at least two fluids, the at least one plate having a high thermal conductivity and providing a portion of the flow path boundary for two fluids of the at least two fluids, thereby providing thermal communication between the two fluids on the opposed surfaces of the plate;    an inlet and outlet for each fluid of the at least two fluids, the inlet and outlet for each fluid being in fluid communication with each flow path for said fluid; and    at least one insert member having a plurality of surface microfeatures, the at least one insert member disposed in fluid communication with at least a portion of at least one flow path for at least one fluid, facing surfaces of the at least one insert member and one of the pair of adjacent plates of the plurality of plates being substantially immediately adjacent, the at least one insert member having a profile substantially conforming to at least one of the pair of adjacent plates, the plurality of surface microfeatures for providing enhanced heat transfer between the at least two fluids, the at least one plate forming a portion of the flow path boundary.    
   
   
       2 . The plate heat exchanger of  claim 1  wherein the plate heat exchanger is of brazed construction comprising the insertion of at least one foil plate between the adjacent plates of the plurality of plates, the at least one foil plate becoming molten and flowing between adjacent plates of the plurality of plates to form brazed nodal contacts between facing surfaces of the adjacent plates of the plurality of plates when the plate heat exchanger is heated to a predetermined temperature below the melting point of the adjacent plates of the plurality of plates, but above the melting temperature of the at least one foil plate, the at least one insert member having a coating layer applied to at least a portion of at least one surface of the at least one insert member to substantially prevent molten metal from the foil plate from flowing into the plurality of microfeatures of the at least one insert member.  
   
   
       3 . The plate heat exchanger of  claim 2  wherein the coating layer is an oxide coating.  
   
   
       4 . The plate heat exchanger of  claim 3  wherein the coating layer is an oxide coating selected from the group consisting of nickel oxide, chromium oxide, aluminum oxide, and zirconium oxide or combinations thereof.  
   
   
       5 . The plate heat exchanger of  claim 1  wherein the plurality of surface microfeatures have geometric attributes.  
   
   
       6 . The plate heat exchanger of  claim 1  wherein the plurality of surface microfeatures correspond to openings sufficiently large to prevent entrapment of a lubricating oil.  
   
   
       7 . The plate heat exchanger of  claim 1  wherein the plurality of surface microfeatures correspond to openings from about 0.002 inches to about 0.050 inches.  
   
   
       8 . The plate heat exchanger of  claim 1  wherein the at least one insert member is an insert plate.  
   
   
       9 . A plate heat exchanger of brazed construction comprising: 
 a plurality of plates, each plate having opposed nonplanar surfaces and perimeter flanges, for providing at least one flow path for each of at least two fluids, wherein facing surfaces and perimeter flanges of a pair of adjacent plates of the plurality of plates define a flow path for each fluid of the at least two fluids, and wherein opposed surfaces of at least one plate of each pair of adjacent plates provides a flow path boundary for two fluids of the at least two fluids, the at least one plate having a high thermal conductivity and providing a portion of the flow path boundary for two fluids of the at least two fluids, thereby providing thermal communication between the two fluids on the opposed surfaces of the plate;    an inlet and outlet for each fluid of the at least two fluids, the inlet and outlet for each fluid being in fluid communication with each flow path for said fluid;    at least one insert member having a plurality of surface microfeatures, the at least one insert member disposed in fluid communication with at least a portion of at least one flow path for at least one fluid, facing surfaces of the at least one insert member and one of the pair of adjacent plates of the plurality of plates being substantially immediately adjacent, the at least one insert member having a profile substantially conforming to at least one of the pair of adjacent plates, the plurality of surface microfeatures for providing enhanced heat transfer between the at least two fluids, the at least one plate forming a portion of the flow path boundary; and    at least one foil plate between the adjacent plates of the plurality of plates, the at least one foil plate becoming molten and flowing between adjacent plates of the plurality of plates to form brazed nodal contacts between facing surfaces of the adjacent plates of the plurality of plates when the plate heat exchanger is heated to a predetermined temperature below the melting point of the adjacent plates of the plurality of plates, but above the melting temperature of the at least one foil plate, the at least one insert member having a coating layer applied to at least a portion of at least one surface of the at least one insert member to substantially prevent molten metal from flowing into the plurality of microfeatures of the at least one insert member.    
   
   
       10 . The plate heat exchanger of  claim 9  wherein the coating layer is an oxide coating.  
   
   
       11 . The plate heat exchanger of  claim 10  wherein the oxide coating is selected from the group consisting of nickel oxide, chromium oxide, aluminum oxide, and zirconium oxide or combinations thereof.  
   
   
       12 . The plate heat exchanger of  claim 9  wherein the plurality of surface microfeatures have geometric attributes.  
   
   
       13 . The plate heat exchanger of  claim 9  wherein the plurality of surface microfeatures correspond to openings sufficiently large to prevent entrapment of a lubricating oil.  
   
   
       14 . The plate heat exchanger of  claim 9  wherein the plurality of surface microfeatures correspond to openings from about 0.002 inches to about 0.050 inches.  
   
   
       15 . The plate heat exchanger of  claim 9  wherein the at least one insert member is an insert plate.  
   
   
       16 . The plate heat exchanger of  claim 9  wherein the at least one insert member is a mesh.  
   
   
       17 . A method for providing an enhanced heat transfer surface for use with a plate heat exchanger including a plurality of plates, each plate having opposed surfaces and perimeter flanges, for providing at least one flow path for each of at least two fluids, wherein facing surfaces and perimeter flanges of a pair of adjacent plates of the plurality of plates define a flow path for each fluid of the at least two fluids, and wherein opposed surfaces of at least one plate of the pair of adjacent plates provides a flow path boundary for two fluids of the at least two fluids, the at least one plate providing a flow path boundary having a high thermal conductivity, thereby providing thermal communication between the two fluids on the opposed surfaces of the plate, an inlet and outlet for each fluid of the at least two fluids, the inlet and outlet for each fluid being in fluid communication with each flow path for said fluid, the step comprising: 
 placing at least one insert member having a plurality of surface microfeatures between at least one pair of facing surfaces of adjacent plates of the plurality of plates defining a fluid flow path;    inserting at least one foil plate between the adjacent plates of the plurality of plates, the at least one foil plate becoming molten and flowing between adjacent plates of the plurality of plates to form brazed nodal contacts between facing surfaces of the adjacent plates of the plurality of plates when the plate heat exchanger is heated to a predetermined temperature below the melting point of the adjacent plates of the plurality of plates, but above the melting temperature of the at least one foil plate; and    applying a coating layer to at least a portion of at least one surface of the at least one insert member to substantially prevent molten metal from the foil plate from flowing into the plurality of microfeatures of the at least one insert member.    
   
   
       18 . The method of  claim 17  wherein the step of applying the coating layer is performed after the step of placing at least one insert member.  
   
   
       19 . The method of  claim 17  wherein the coating layer is an oxide.  
   
   
       20 . A plate heat exchanger of brazed construction comprising: 
 a plurality of plates, each plate having opposed nonplanar surfaces and perimeter flanges, for providing at least one flow path for each of at least two fluids, wherein facing surfaces and perimeter flanges of a pair of adjacent plates of the plurality of plates define a flow path for each fluid of the at least two fluids, and wherein opposed surfaces of at least one plate of each pair of adjacent plates provides a flow path boundary for two fluids of the at least two fluids, the at least one plate having a high thermal conductivity and providing a portion of the flow path boundary for two fluids of the at least two fluids, thereby providing thermal communication between the two fluids on the opposed surfaces of the plate;    an inlet and outlet for each fluid of the at least two fluids, the inlet and outlet for each fluid being in fluid communication with each flow path for said fluid;    a plurality of surface microfeatures in fluid communication with at least a portion of at least one flow path for at least one fluid, the plurality of surface microfeatures for providing enhanced heat transfer between the at least two fluids, the at least one plate forming a portion of the flow path boundary;    at least one foil plate between the adjacent plates of the plurality of plates, the at least one foil plate becoming molten and flowing between adjacent plates of the plurality of plates to form brazed nodal contacts between facing surfaces of the adjacent plates of the plurality of plates when the plate heat exchanger is heated to a predetermined temperature below the melting point of the adjacent plates of the plurality of plates, but above the melting temperature of the at least one foil plate; and    a coating layer applied to the plurality of surface microfeatures to substantially prevent molten metal from flowing into the plurality of microfeatures.    
   
   
       21 . The plate heat exchanger of  claim 20  wherein the coating layer contains at least a portion of the plurality of microfeatures.  
   
   
       22 . The plate heat exchanger of  claim 20  wherein at least one insert member contains at least a portion of the plurality of surface microfeatures, the at least one insert member being disposed in fluid communication with at least a portion of at least one flow path for at least one fluid, facing surfaces of the at least one insert member and one of the pair of adjacent plates of the plurality of plates being substantially immediately adjacent, the at least one insert member having a profile substantially conforming to at least one of the pair of adjacent plates.  
   
   
       23 . The plate heat exchanger of  claim 20  wherein at least a portion of the plurality of microfeatures are formed in at least one plate of the plurality of plates.