GB503030A - Improvements in steam boilers of the locomotive boiler type - Google Patents

Abstract

503,030. Steam superheaters ; water chambers in ateam-boiler fireboxes. TENNANT, W. J. (Aktiebolaget Ljtmgstroms Angturbin) Oct. 11, 1937, No. 27623. [Classes 123 (ii) and 123 (iii)] Superheaters 68 of locomotive steam boilers are arranged wholly or in part in the firebox and are protected from direct heat radiation by a brick arch 15 and one or more boxes receiving cooling medium and disposed at right-angles to the boiler axis, all the combustion gases passing over the firebox superheater. The boxes may comprise thermic siphons 56, 57, 66 open respectively to the side and crown water spaces and connected by pipes 64, 65, the arch being supported by tubes 51 .. 54 extending between siphons 56, 57 and the front firebox plate 55. A low temperature superheater in series with superheater 68 may be located in the smoke box. Another construction provides a brick arch resting on two arch tubes and on the enlarged bottom portions of two longitudinally arranged thermic siphons, a transverse air chamber protecting the superheater and having openings delivering secondary combustion air below the arch. The superheater tubes are divided into five groups separated at their lower portion by the arch tubes and siphons and at their upper portion by water-tubes in the same inclined plane as the superheater and extending between the rear and crown plates of the firebox. A pre-superheater in the smokebox consists of two groups of annular tubes surrounding a circular screen of pivoted flaps normally forming a closed wall but adapted to be opened to facilitate inspection of the smoke tubes,