Brazed heat exchanger

Abstract

A brazed heat exchanger having a stack of heat exchanger plates, each with an inflow hole and an outflow hole, that are arranged such that closed and open flow ducts for different media alternate in a stack direction. In the open flow ducts are two endpieces with a hole whose edge extends around the inflow hole or around the outflow hole respectively. The endpieces are deformed metal sheets with corrugations that form ducts, The metal sheets include flow openings for the medium flowing through the open flow ducts. The hole edges are deformed and have a height approximately corresponding to a height of the open flow duct, and are arranged close to a rim hole of the inflow hole or of the outflow hole.

What is claimed is: 
     
         1 . A brazed heat exchanger configured to be received in a housing and configured to transfer heat between a first medium and a second medium, the brazed heat exchanger comprising:
 a plurality of heat exchanger plates arranged to form a stack, each of the plurality of heat exchanger plates having a thickness and including an inflow hole and an outflow hole, the plurality of heat exchanger plates arranged in the stack to define a plurality of closed flow ducts between adjacent heat exchanger plates for the first medium and a plurality of open flow ducts between adjacent heat exchanger plates for the second medium, the closed and open flow ducts alternating in a stack direction of the plurality of heat exchanger plates; and   first and second endpieces in each of the plurality of open flow ducts,   wherein the first and second endpieces each include a metal sheet with corrugations that form ducts, each having a flow opening for the second medium flowing through the open flow ducts, the first and second endpieces each further include a hole having an edge that is deformed such that the edge has a height approximately corresponding to a height of the open flow ducts,   wherein the edge of each of the first endpieces extends around the inflow hole and the edge of each of the first endpieces is close to a rim hole of the inflow hole,   wherein the edge of each of the second endpieces extends around the outflow hole and the edge of each of the second endpieces is close to a rim hole of the outflow hole.   
     
     
         2 . The brazed heat exchanger of  claim 1 , wherein the edge of each of the first endpieces is formed with a braze gap around the inflow hole, and wherein the edge of each of the second endpieces is formed with a braze gap around the outflow hole. 
     
     
         3 . The brazed heat exchanger of  claim 1 , wherein the rim holes of the inflow hole and of the outflow hole of two of the plurality of heat exchanger plates forming one of the plurality of closed flow ducts engage into one another and bear against one another in opposite directions. 
     
     
         4 . The brazed heat exchanger of  claim 2 , wherein the edge of each of the first and second endpieces is approximately vertically standing, wherein the braze gaps of the first and second endpieces are arranged between the approximately vertically standing edge and the rim hole. 
     
     
         5 . The brazed heat exchanger of  claim 1 , wherein the ducts of the first and second endpieces have at least two different duct lengths. 
     
     
         6 . The brazed heat exchanger of  claim 1 , wherein at least one of the ducts of the first and second endpieces has a curvature. 
     
     
         7 . The brazed heat exchanger of  claim 6 , wherein the curvature corresponds approximately to a curvature of the edge and runs approximately concentric thereto. 
     
     
         8 . The brazed heat exchanger of  claim 6 , wherein at least one of the ducts of the first and second endpieces are of arcuate form so as to extend around a center, with a flow opening at the start of the duct and a flow opening at the end of the duct. 
     
     
         9 . The brazed heat exchanger of  claim 1 , wherein a longest of the ducts of the first and the second endpieces extends close to the edge and around a major part of a circumference thereof. 
     
     
         10 . The brazed heat exchanger of  claim 1 , wherein the open and the closed flow ducts are formed from pairs of the heat exchanger plates, wherein the closed flow ducts are arranged within the plate pairs and the open flow ducts are arranged between the plate pairs. 
     
     
         11 . The brazed heat exchanger of  claim 1 , wherein the closed flow ducts include lamella. 
     
     
         12 . The brazed heat exchanger of  claim 1 , wherein the open flow ducts are formed outside regions occupied by the metal sheets with studs formed into the heat exchanger plates. 
     
     
         13 . The brazed heat exchanger of  claim 12 , wherein the studs are formed with a height approximately half that of the open flow duct, with opposite studs being supported and connected by brazing. 
     
     
         14 . The brazed heat exchanger of  claim 1 , wherein between one side of one of the first endpieces and one heat exchanger plate, there is situated a braze foil or paste which approximately corresponds to a circumference of said first endpiece. 
     
     
         15 . The brazed heat exchanger of  claim 14 , wherein between the other side of said one of the first endpieces and an other heat exchanger plate, there is arranged another braze foil or paste which extends approximately over the entire other heat exchanger plate, including one of the second endpieces. 
     
     
         16 . The brazed heat exchanger of  claim 15 , wherein the other braze foil or paste is situated at least at locations at which brazing is performed, wherein said braze foil or paste has voids at other locations where no brazing is performed. 
     
     
         17 . The brazed heat exchanger of  claim 1 , wherein the metal sheets are configured so as to be able to admit flow from opposite directions. 
     
     
         18 . A brazed heat exchanger configured to be received in a housing and configured to transfer heat between a first medium and a second medium, the brazed heat exchanger comprising:
 a plurality of heat exchanger plate pairs arranged into a stack, open flow ducts arranged between adjacent ones of the heat exchanger plate pairs;   a vertical inflow duct extending through the stack at a first end of the stack and a vertical outflow duct extending through the stack at a second end of the stack, the vertical inflow and outflow ducts being fluidly connected by a closed flow duct within each of the heat exchanger plate pairs to allow for the first medium to flow between the vertical inflow and outflow ducts; and   a plurality of metal sheets provided within the open flow ducts at both the first end and the second end of the stack, each of the metal sheets being joined to adjacent ones of the heat exchanger plate pairs to provide structural support thereto,   wherein each of the plurality of metal sheets is provided with ducts to allow for flow of the second medium around the vertical inflow and outflow ducts.   
     
     
         19 . The heat exchanger of  claim 18 , wherein the metal sheets are deformed to have corrugations corresponding in height to the open flow ducts arranged between adjacent ones of the heat exchanger plate pairs, the ducts provided within the metal sheets being defined by said corrugations. 
     
     
         20 . The heat exchanger of  claim 18 , wherein each of the ducts provided within the metal sheets includes a flow opening at the start of the duct and a flow opening at the end of the duct, wherein at least some of said flow openings are in fluid communication with the open flow ducts arranged between adjacent ones of the heat exchanger plate pairs.