Abstract: A steam generator (2) is described in which a combustion chamber has at least one combustion chamber wall formed by a plurality of longitudinal furnace tubes (10) for passage of an evaporatable flow medium, connected together in gas-tight manner by tube webs. As will be familiar different tubes are likely to be subjected to a heat input in use that varies when the combustion chamber is fired. The tube bores of the furnace tubes are larger where subject to higher heat input than where subject to lower heat input. In particular the tube bores of the furnace tubes are generally larger in the middle region of the combustion chamber wall than at the transversely peripheral regions of the combustion chamber wall.

Abstract: A mobile coal-fired fluidized bed furnace system (10) is provided for generating steam to power a locomotive. Coal is combusted within the fluidized bed furnace chamber (30) in the fluidizing air to produce a hot flue gas which pass from the furnace chamber (30) through a boiler tank (90) and an economizer (34). The steam generated in the boiler bank and the walls of the furnace chamber is collected in steam drum (40) and passed therefrom through an in-bed superheater (100) and thence to the power generating means (22) to produce the power which drives the locomotive.

Abstract: A low pressure steam generator comprising a horizontal coil of tubing having a single upper steam outlet header and a pair of lower water inlet headers on opposite sides of the coil. Curved taps connect the successive turns of the coil with the steam header, and curved taps connect the water headers alternately to the coil turns to give a structure which is resistant to differential thermal expansion and which is minimally susceptible to surging, pressure variation, and entrainment of water in the steam input.

Abstract: A low pressure steam generator including a water tube structure of plural, substantially annular coaxial portions each connected individually by separate conduits to a steam header above and a water header below. The portions coact with suitable baffle means to comprise a combustion chamber, but are significantly spaced to allow combustion products to pass between them from a burner directing a flame axially within the chamber, and the greater part of the combustion products are directed upward by the baffle means to bathe the steam header outside the combustion chamber as well. Means are provided for maintaining the water to be vaporized at a suitable level, and the whole is enclosed in a suitable housing to the top and bottom of which the headers are secured. The tube structure may be a continuous helix or an array of discrete annuli.