Abstract: A waste heat boiler has an elongated horizontally oriented gas pass, a steam drum extending lengthwise of the gas pass but wholly outside the same at an elevation near but not above the roof of the gas pass. Transversely extending rows of nested water tubes which are preferably L-shaped with vertical and substantially horizontal stretches have the outer extremities of their substantially horizontal stretches joined to vertical feeder headers that extend upwardly along one side wall of the gas pass, and have the upper extremities of their vertical stretches joined to collecting headers that extend transversely across the gas pass just below its roof. The rows of tubes are arranged in groups or bundles, each held together by distributing headers and receiving headers that are separately connected with the steam drum and to which are respectively joined the feeder headers and the receiving headers.

Abstract: A vertical watertube boiler in which a bank of vertically oriented uniformly spaced watertubes, located in an upright cylindrical shell that has enlarged diameter upper and lower end portions, connect paired headers mounted on and protruding into diametrically opposite sides of the enlarged diameter end portions of the shell, the end portions of the tubes being bent laterally outward and joined to wall portions common to the headers and the gas pass formed by the shell; the headers associated with the upper enlarged diameter end portion of the shell being connected by risers with a steam drum and the headers at the lower enlarged end portion of the shell being connected with the steam drum by downcomers.

Abstract: A vertical firetube boiler in which the upper tube sheet has a dished formation to coact with an annular baffle spaced down from the peripheral portion of the upper tube sheet, to cause the circulating steam-water mixture in the boiler to flow radially outward along the underside of the upper tube sheet to a circular row or belt of holes that open to an annular steam collecting chamber.

Abstract: A vertical firetube boiler in which the upper tube sheet has a dished formation to coact with an annular baffle spaced down from the peripheral portion of the upper tube sheet, to cause the circulating steam-water mixture in the boiler to flow radially outward along the underside of the upper tube sheet to a circular row or belt of holes that open to an annular steam collecting chamber.