Vertical radiation tank

A vertical radiation tank (10), more particularly for gaining heat from process gases of ash forming, carbon containing fuels, comprising a vessel (11) provided inside its jacket with diaphragm pipe walls (1) traversed by a coolant and bounding a flow space to be traversed by process gases, said space having at the top a central inlet for the process gas, on the lower side an inverting space for inverting the direction of flow of the process gas and adjacent thereto at least one outlet for the cooled process gas, said inverting space being bounded by a water space for capturing therein locally separated ash particles characterized in that the diaphragm pipe walls comprise a cylindrical, first diaphragm pipe wall concentric with the jacket of the vessel and covering the length of the flow space and the inverting space, a plurality of second pipe walls radially arranged inside the former, a funnel-shaped, third diaphragm pipe wall (3) bounding the radial pipe walls (2) on their underside and a short, cylindrical fourth diaphragm pipe wall adjoining the funnel-shaped diaphragm pipe wall, the third and fourth diaphragm pipe walls being formed by pipes branched from the first diaphragm pipe wall, the cylindrical first diaphragm pipe wall is formed by U-section pipes lying wholly or partly side by side, one limb of which at the top is connected with an annular collecting duct for the water supply and the other limb is connected with an annular collecting duct for the water outlet and the radial second pipe walls are formed by a plurality of co-planar U-section pipes, one limb of which at the top is connected with a collecting duct for the water supply and the other limb is connected with a collecting duct for the water outlet.