Plate-type exchanger, heat exchanger plate and method for producing same

Plate-type heat exchanger for fluid media with at least one inlet (9) and at least one outlet (11) for a first slightly aggressive medium, with at least one inlet (12) and at least one outlet (10) for a second, more aggressive medium, and with a number of heat-exchanger plates (3) that are arranged in effective connection with respect to fluid with the inlets and the outlets in the plate-type heat exchanger, such that the media each flow in adjacent plate intermediate spaces, at least a few of the heat-exchanger plates (3) are constructed as a heat-exchanger plate (3a, 3b) comprising a first material, and a different material is provided or coated on the first material essentially only in those partial regions of its surface on at least one of a front or a back side in which the heat-exchanger plate is adapted to come into contact with the second more aggressive of the fluid media, wherein the heat-exchanger plate (3a, 3b) has, on the front side and the back side, a large surface area, heat-exchanging region (18a, 18b) and at least four connection regions (16a, b;

• 17a, b;
• 19a, b;
• 20a, 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 (5a, 7a, 4b, 6b), the heat-exchanger plate (3a, 3b) is made from the different material or is coated with the different material on its surface (18a, 19a, 20a) adapted to come in contact in the heat-exchanging region (18a) with the relatively more aggressive of the fluid media, in the heat-exchanging region (18a) as well as the connection regions (19a, 20a) connected to the heat exchanging region with respect to flow, and the heat-exchanger plate (3a, 3b) is made from the different material or is coated with the different material on its surface (16b, 17b, 18b) coming in contact in the heat-exchanging region (18b) with the other of the fluid media only in the connection regions (19b, 20b) for one medium.

Method for the production of a heat-exchanger plate (3a, 3b) for a plate-type heat exchanger, wherein front side of the plate is allocated to a less corrosive medium on its heat-exchanging surface (18b) and connection regions (16b, 17b) in flow connection with the front side heat-exchanging surface are produced from a less corrosion-resistant material, connection regions (19b, 20b) for a corrosive medium and made from a more corrosion-resistant material are connected to these regions, while on a back side of the plate, the heat-exchanging surface (18a) and the connection regions (19a, 20a) in flow connection with the back side heat-exchanging surface for the more corrosive medium and made from a more corrosion-resistant material and the remaining connection regions (16a, 17a) made from the less corrosion-resistant material are produced, wherein the heat-exchanger plate (3a, 3b) has, on the front side and the back side, at least four of the connection regions (16a, b;

• 17a, b;
• 19a, b;
• 20a, b) each containing one through-flow opening (4-7) for the heat-exchanging medium, wherein the connection regions alternately open into the heat-exchanging region or are separated from the heat-exchanging region by seals (5a, 7a, 4b, 6b), the heat-exchanger plate (3a, 3b) is made from the more corrosion-resistant material or is coated with the more corrosion-resistant material on the surfaces (18a, 19a, 20a) adapted to come in contact in the heat-exchanging region (18a) with the more corrosive medium, in the heat-exchanging region (18a) as well as the connection regions (19a, 20a) connected to the heat exchanging region with respect to flow, and the heat-exchanger plate (3a, 3b) is made from the less corrosion-resistant material or is coated with the less corrosion-resistant material on the surfaces (16b, 17b, 18b) coming in contact in the heat-exchanging region (18b) with the less corrosive medium only in the connection regions (19b, 20b) for less corrosive medium, and the materials are connected to each other in a fitting way, whereupon a multi-layer plate formed in this way is profiled.