US Patent 7640969 Heat exchanger tube, heat exchanger and use

According to the invention, in order to prevent a film from forming which obstructs the transfer of heat in heat exchanger pipes, the heat exchanger pipe comprises an external side which is adjacent to the external surface and which is impinged upon by a steam medium, and an inner side which is adjacent to an inner surface and which is impinged upon by a coolant, such that the outer surface is provided with a first layer which reduces the adhesion of the steam on the outer surface and/or the inner surface is provided with a second layer which reduces the adhesion of a coolant to the inner surface and which is embodied as a biocidal layer. The invention relates to a heat exchanger and to the use thereof.