Patent ID: 8117995
Filing Date: 2012-02-21
Classification: F28D,F28F

Abstract:
1. A method of protecting a heat exchanger that includes a flue gas cooler having plastic heat recovery tubes arranged on a counterflow principle in heat exchange connection with flue gases generated by a thermal power boiler, which heat recovery tubes are connected by an inlet chamber to an inlet tube and by an outlet chamber to an outlet tube, which form, together with a heater, a liquid cycle in which a liquid heat exchange medium is recirculated by a pump, said method comprising: guiding vapor, which is generated at an end portion of the heat recovery tubes, to a protection circuit that is separate from the liquid cycle, by guiding the vapor along a separate flow channel from the outlet chamber to an upper portion of an expansion vessel; and guiding a liquid heat exchange medium from a lower portion of the expansion vessel directly to the inlet chamber or to the inlet tube, in a vicinity of the inlet chamber, by a separate return duct, so as to enable natural circulation of the heat exchange medium in the heat recovery tubes without the use of external energy.