Patent ID: 8770268

Claim:
Heat-exchanger plate ( 3 a , 3 b ) for a plate-type heat exchanger comprising a plate with through-flow openings ( 4 - 7 ) arranged in a plane of the plate for fluid media, the plate ( 3 a , 3 b ) is constructed of a first material, and comprises a different material or is coated with the different material essentially only in those partial regions ( 18 a ; 19 a, b ; 20 a, b ) of its surface on at least one of a front or back side in which the heat-exchanger plate ( 3 a , 3 b ) is adapted to come in contact with a relatively more aggressive of the fluid media, wherein the heat-exchanger plate ( 3 a , 3 b ) has, on the front side and the back side, a large surface area, heat-exchanging region ( 18 a , 18 b ) and at least four connection regions ( 16 a, b ; 17 a, b ; 19 a, b ; 20 a, b ) each containing one of the through-flow openings ( 4 - 7 ) for the heat-exchanging media, wherein the connection regions alternately open into the heat-exchanging region or are separated from the heat-exchanging region by seals ( 5 a , 7 a , 4 b , 6 b ), the heat-exchanger plate ( 3 a , 3 b ) is made from the different material or is coated with the different material on its surface ( 18 a , 19 a , 20 a ) adapted to come in contact in the heat-exchanging region ( 18 a ) with the relatively more aggressive of the fluid media, in the heat-exchanging region ( 18 a ) as well as the connection regions ( 19 a , 20 a ) connected to the heat exchanging region with respect to flow, and the heat-exchanger plate ( 3 a , 3 b ) is made from the different material or is coated with the different material on its surface ( 16 b , 17 b , 18 b ) coming in contact in the heat-exchanging region ( 18 b ) with the other of the fluid media only in the connection regions ( 19 b , 20 b ) for one medium.