Vertical firetube waste heat boiler

A boiler having vertical firetubes, upper and lower sheets to which the opposite ends of the firetubes are connected, an upright substantially cylindrical shell surrounding the firetubes in radially spaced relation to all of them and joined to the peripheral edges of the tube sheets to coact with the tube sheets in defining an upright closed vessel, and means including a downcomer outside the vessel for communicating the top and bottom of the vessel so that during operation of the boiler the vessel contents flow upwardly, said boiler being characterized by:

• A. the upper tube sheet having its peripheral edge at a level substantially above its central portion, and being upwardly inclined outwardly from its central portion along every radius to induce radially outward flow of the vessel contents along the underside of the upper tube sheet;
• B. an annular baffle projecting radially inward from the shell at a level below the junction of the shell with the upper tube sheet to direct the upwardly flowing vessel contents towards the axis of the vessel and against the center of the upper tube sheet to assure a positive radially outward flow of the vessel contents across the underside of the upper tube sheet that wipes away any steam bubbles in contact therewith;
• and
• C. the shell having circumferentially spaced outlets closely adjacent to and above the peripheral edge of the upper tube sheet through which the steam-water mixture constituting the contents of the vessel leaves the same.