Abstract: Device for heating or cooling infusion fluids or injectable fluids comprising a heat exchanger in the form of a hollow cylindrical or truncated, conical, double cased pot, open at the top; the outer wall being higher than the inner wall of the double casing, wherein the hollow space of the casing is sealed by a ledge surrounding the upper brim of the inner wall and extending up to the outer wall whereby the ledge is provided with connection branches spaced apart from each other and extending into the interior of the pot, where two parallel ridges form a double helix respectively a double thread within the whole of the hollow space of the casing between the walls, wherein each of the ends of the double helix is connected to one of the connection branches and the return of the double helix is located close to the bottom of the pot as a semi-circular arch.