GB812224A - Improvements in or relating to steam generators or heating boilers - Google Patents

Abstract

812,224. Boiler furnaces. OHLSSON, O. A. Feb. 4, 1957 [Feb. 2, 1956 ; May 17, 1956 ; Nov. 2, 1956], No. 3779/57. Class 51 (1). [Also in Group XIII] A steam generator or water-heating boiler comprises an outer water casing 1, Fig. 1, and an inner furnace casing 2 surrounding a lower cyclone chamber and an upper flame chamber wherein primary air is supplied beneath the grate and secondary air from tangential nozzles 17 in the cyclone chamber. The gases pass from the cyclone chamber through an outlet 14 of an annular member 12 whence tertiary air is centrally directed from nozzles 15 up into the flame chamber. The combustion products reflected from the wall 3 flow down to tubes 19 where they are drawn off by chimney draught towards cleaning doors 9 and through tubes 20 to a soot compartment 8, delivering heat to the water casing during their passage. A furnace door 4 has tapered vertical side walls, with the widest section innermost for greater accessibility to the cyclone chamber. In another embodiment, Fig. 2, the boiler is divided into a cyclone radiant section and a convection section connected by a water-cooled gas passage 22. Heating tubes 20a extend between tube-plates 3a to heat a water compartment and a pipe 21 open at both ends allows a free flow of water and steam in the compartment. Steam is drawn from domes 24 by tubes 25 to a common discharge main 26. In a further embodiment, Fig. 3, combustion gases are led from the flame chamber 35 upwardly through tubes 42, 47 which heat a steam dome formed by a cavity beneath a roof 45 into which cold air is introduced in cross-current streams around the tubes by a fan 49. The gases are then led by tubes 47 to an air-tight gas compartment 50 before escaping to a chimney 52.