Flat product of metal, in particular, in the form of a wall for heat exchangers, as well as a heat exchanger with a double layer wall of copper and titanium
The invention pertains to a flat product in the form of a wall for a heat exchanger that is operated with cooling mediums in the form of corrosive liquids that contain biological organisms. In order to protect the wall of the heat exchanger against corrosion on the side that comes in contact with the cooling medium and to prevent biological organisms from settling down on the heat exchanger wall, the wall consists of a titanium or titanium alloy layer and a copper/titanium alloy layer that is integrally connected to the titanium or titanium alloy layer by means of an intermediate alloy layer.
1. A method for manufacturing a heat exchanger including a wall that is exposed to cooling mediums in the form of liquids containing biological organisms, the method comprising:
plating a strip of a titanium material with a strip of a copper material to form a composite strip;
shaping the composite strip into plates or tubes;
subjecting the composite strip to a heat treatment before or after the plates or tubes are shaped to form an alloy boundary layer between the two materials, the heat treatment of the composite strip achieving a thorough alloying of the copper materials; and
joining the plates or tubes to obtain heat exchangers with the thorough alloyed copper material of the composite strip facing the cooling mediums to provide protection against biofouling.
2. The method for manufacturing a heat exchanger according to claim 1 , wherein the heat treatment takes place in an inert gas atmosphere at a temperature between 800° C. and 1000° C.
3. The method for manufacturing a heat exchanger according to claim 1 , wherein the heat treatment is carried out for a duration between 5 and 15 minutes.
4. The method for manufacturing a heat exchanger according to claim 1 , wherein the heat treatment of the composite strip is carried out in the form of a continuous operation.
5. The method for manufacturing a heat exchanger according to claim 1 , wherein the heat treatment takes place at a temperature which is below the melting points of the titanium material and the copper material.