Abstract: The system includes means for cyclically putting into operation a circuit for controlling and regulating a DC generator connected between the structure to be protected which constitutes a cathode and the anodes of a group of anodes which are insulated from the structure and are in contact with the electrolyte in which said structure is placed. The circuit includes means for reading the potential provided by a reference electrode, for calculating the potential difference between the structure and the electrode potential as read, and for comparing the calculated potential difference with upper and lower thresholds. The value of the voltage output from the generator may be adjusted by means in steps of predetermined value as a function of the comparison signals delivered by the comparator. The system is particularly applicable to protecting underground or underwater metal structures from corrosion.

Abstract: A reduced wreath condensation boiler. A feed duct for fresh oxygen-carrying air taken from the atmosphere and an exhaust duct for exhausting diluted combustion products to the atmosphere downstream from the extractor fan are essentially parallel, but not coaxial, minimizing heat exchange. A first heat exchanger is disposed above the heating body for providing heat exchange between the fresh air from the feed duct and the combustion products from the heating body prior to dilution. Deflectors channel a portion of the air from said first heat exchanger to sweep the free space situated between the heating body and its airtight enclosure, while the remainder of the air from the first heat exchanger is directed towards the burner. At least one calibrated orifice injects the air which has swept over the heating body into the exhaust duct for the combustion products upstream from the extractor fan. This boiler reduces the wreath of water vapor where the flue gases are exhausted to the atmosphere.