Brazed Heat Exchanger and Production Method

Abstract

The invention relates to a heat exchanger which is brazed in a brazing furnace, comprising stacked heat exchanger parts which provide first channels and second channels, and with at least two brazing materials, the one brazing material in the first channels being different than the other brazing material in the second channels. According to one alternative, said heat exchanger is improved by virtue of the fact that there is the other or the one brazing material in one or in a few of the first channels or the second channels or in one or in a few of the first and the second channels, or the other and the one brazing material are present arranged in part regions.

What is claimed is: 
     
         1 . A brazed heat exchanger, comprising:
 a plurality of stacked plates defining a plurality of first channels for a first liquid and a plurality of second channels for a second liquid alternating in a plate stack direction;   a first brazing material providing brazed connection seams in each one of the plurality of first channels; and   a second brazing material different from the first brazing material providing brazed connection seams in at least some of the plurality of second channels, wherein at least one of the plurality of second channels has brazed connection seams provided by the first brazing material.   
     
     
         2 . The brazed heat exchanger of  claim 1 , wherein said at least one of the plurality of second channels additionally has brazed connection seams provided by the second brazing material. 
     
     
         3 . The brazed heat exchanger of  claim 2 , wherein said at least one of the plurality of second channels includes an inlet region for at least one of the fluids arranged at one end thereof, an outlet region for at least one of the fluids arranged at an opposing end thereof, and a central region between the inlet region and the outlet region, wherein brazed connection seams in the inlet and outlet regions are provided by the first brazing material and brazed connection seams in the central region are provided by the second brazing material. 
     
     
         4 . The brazed heat exchanger of  claim 1 , wherein the second brazing material provides brazed connection seams in each one of the plurality of second channels. 
     
     
         5 . The brazed heat exchanger of  claim 1 , wherein said at least one of the plurality of second channels includes an uppermost or a lowermost one of the plurality of second channels in the plate stack direction. 
     
     
         6 . The brazed heat exchanger of  claim 1 , wherein said at least one of the plurality of second channels includes both an uppermost and a lowermost one of the plurality of second channels in the plate stack direction. 
     
     
         7 . The brazed heat exchanger of  claim 1 , wherein the brazed connection seams in at least all of the plurality of second channels other than the uppermost two second channels and the lowermost two second channels are provided exclusively by the second brazing material. 
     
     
         8 . The brazed heat exchanger of  claim 7 , wherein the brazed connection seams in at least all of the plurality of second channels other than the uppermost second channel and the lowermost second channel are provided exclusively by the second brazing material. 
     
     
         9 . The brazed heat exchanger of  claim 1 , further comprising:
 a first and a second corrugated channel plate arranged within one of the at least one of the plurality of second channels that has brazed connection seams provided by the first brazing material; and   a corrugated slat arranged within said channel between the first and second corrugated channel plates.   
     
     
         10 . The brazed heat exchanger of  claim 9 , wherein the first and second corrugated channel plates are joined to those ones of the plurality of stacked plates defining said channel by brazed connection seams provided by the first brazing material, and wherein the corrugated slat is joined to those ones of the plurality of stacked plates defining said channel by brazed connection seams provided by the second brazing material. 
     
     
         11 . The brazed heat exchanger of  claim 1 , wherein the first brazing material is a copper brazing material and wherein the second brazing material is an iron brazing material. 
     
     
         12 . A brazed heat exchanger, comprising:
 a first plate;   a second plate joined to the first plate by connected plate edges to form a first closed channel;   a first part region of the first closed channel in which a first brazing material is arranged and a second part region of the first closed channel in which a second brazing material different from the first brazing material is arranged;   a third plate joined to the second plate by connected plate edges to form a second closed channel, wherein the first brazing material but not the second brazing material is arranged in the second close channel; and   a fourth plate joined to the third plate by connected plate edges to form a third closed channel, wherein the second brazing material but not the first brazing material is arranged in the second closed channel.   
     
     
         13 . The brazed heat exchanger of  claim 12 , further comprising:
 a first inlet channel and a first outlet channel extending through the first, second, third, and fourth plates, wherein a cooling liquid is fed to the first and the third closed channels by the first inlet channel; and   a second inlet channel and a second outlet channel extending through the first, second, third, and fourth plates, wherein an oil is fed to the second closed channel by the second inlet channel.   
     
     
         14 . The brazed heat exchanger of  claim 13 , wherein the first and second inlet and outlet channels are arranged within the first part region of the first closed channel. 
     
     
         15 . The brazed heat exchanger of  claim 12 , wherein the second part region of the first closed channel is a middle region of the first flow channel. 
     
     
         16 . The brazed heat exchanger of  claim 12 , wherein the second, third, and fourth plates are trough-shaped plates that are stacked inside one another and wherein the first plate is a base plate or a cover plate. 
     
     
         17 . A method of producing a brazed heat exchanger, comprising:
 assembling a plurality of heat exchanger parts into a stack to provide a set of first flow channels and a set of second flow channels in alternating sequence through the stack;   arranging a plurality of first corrugated slats within the set of first flow channels;   providing a first brazing material between peaks and troughs of the plurality of first corrugated slats and surfaces of the heat exchanger parts;   arranging a plurality of second corrugated slats within the set of second flow channels;   providing a second brazing material different from the first brazing material between peaks and troughs of the plurality of second corrugated slats and surfaces of the heat exchanger parts;   arranging a plurality of corrugated plates within the set of second flow channels;   providing a brazing material between surfaces of the plurality of corrugated plates and surfaces of the heat exchanger parts, wherein that brazing material is the first brazing material in one or more of the second flow channels; and   heating the stack to a temperature sufficient to melt both the first and the second brazing materials.   
     
     
         18 . The method of  claim 17 , wherein the first brazing material is a copper brazing material and wherein the second brazing material is an iron brazing material. 
     
     
         19 . The method of  claim 17 , wherein the plurality of corrugated plates are arranged in inlet and outlet regions of the set of second flow channels. 
     
     
         20 . The method of  claim 17 , further comprising:
 assembling a base plate at one end of the stack of heat exchanger parts; and   assembling a cover plate at another end of the stack of heat exchanger parts opposite the one end, wherein one of the one or more second flow channels having the first brazing material between surfaces of the plurality of corrugated plates and surfaces of the heat exchanger parts is the second flow channel nearest either the base plate or the cover plate.