Abstract: A steam generator comprising water/steam tubes passing through the steam generator from the water inlet to the superheated steam outlet, horizontally arranged in tube banks, preferably flat tube banks, perpendicularly crossed by the fumes, the tubes ascend along the steam generator axis from one tube bank the other, with an oblique path so to expose the tube to the fume flow in different positions at each tube bank, the tubes are divided into two or more separate branches, each branch fed by a header distinct from the others, the steam generator being once-through in pure counter-current, vertical or horizontal, the headers of the outlet superheated steam are grouped at direct contact in a bundle, and they are thermally insulated from the outside.

Abstract: A steam generator comprising: water/steam tubes passing through the steam generator from the water inlet (62, 63, 64) to the superheated steam outlet (68, 69, 610), horizontally arranged in tube banks, preferably flat tube banks, perpendicularly crossed by the fumes (61), the tubes ascend along the steam generator axis from one tube bank to the other, with an oblique path so to expose the tube to the fume flow (61) in different positions at each tube bank, the tubes are divided into two or more separate branches (65, 66, 67), each branch fed by a header distinct from the others, the steam generator being once-through in pure countercurrent, vertical or horizontal, the headers (61, 69, 610) of the outlet superheated steam are grouped at direct contact in a bundle, and they are thermally insulated from the outside.