Abstract: A continuous-flow boiler has a two-section construction with gas-tightly welded walls and having a structure forming a combustion-chamber nose disposed beneath a horizontal section connecting both sections of the two-section boiler and including combustion chamber walls formed of a helical winding made up of wound parallel tubes which terminate in transition headers located externally to the combustion chamber walls at a point of transition of the tubes into vertical-tube walls extending upwardly from the helical winding, the combustion-chamber nose having a forward edge and an upper nose incline extending for a given distance along the top of the helical winding toward a front wall of the combustion chamber walls, two of the transition headers being disposed respectively adjacent lateral walls of the combustion chamber and extending from the front wall and terminating at the forward edge of the combustion-chamber nose, the tubes of the helical winding, in the region of the nose, being bent upwardly unwelded,

Abstract: To reduce the temperature difference between a straight tube bundle and the housing surrounding the same in a steam generator assembly for pressurized water reactors, a preheater for feed water is provided, and part of the pressurized water, after it has flowed through the heat exchanger or steam generator proper, is used for heating the feedwater in the preheater.