Patent ID: 9694435
Date: 2017-07-04
CPC Classifications: B21D,B22F,B23K,B32B,C22C,C23C,F28D,F28F,Y10T

Claim:
1. A method for producing a permanently joined plate heat exchanger comprising a plurality of metal heat exchanger plates having a solidus temperature above 1100° C., provided beside each other and forming a plate package with first plate interspaces for a first medium and second plate interspaces for a second medium, wherein the first and second plate interspaces are provided in an alternating order in the plate package, wherein each heat exchanger plate comprises a heat transfer area and an edge area which extend around the heat transfer area, wherein the heat transfer area comprises a corrugation of elevations and depressions, wherein said corrugation of the plates are provided by pressing the plates, the method comprising applying a melting depressant composition on a first surface of the corrugation of elevations and depressions on the first side of a first plate, the melting depressant composition comprising bringing the corrugation of elevations and depressions on a second side of a second plate into contact with the melting depressant composition on the corrugation of elevations and depressions on the first side of the first plate by stacking the plates into a plate package, heating the first and second plates to a temperature above 1100° C., said surface of the corrugation of elevations and depressions on the first side of the first plate thereby melting such that a surface layer of the first plate melts and, together with the melting depressant component, forms a molten metal layer that is in contact with the corrugation of elevations and depressions on the second plate at contact points between the first plate and the second plate, and allowing the molten metal layer to solidify, such that a joint is obtained at the contact points between the plates in the plate package.