GB822817A - Improvements in tubulous vapour generating and vapour heating units - Google Patents

Abstract

822,817. Water-tube steam boilers; superheaters. BABCOCK & WILCOX Ltd. May 9, 1956 [May 10, 1955], No. 14393/56. Classes 123(2) and 123(3) [Also in Group XII] A natural circulation, top-supported steam generating unit comprises a steam and water drum 10, Fig. 1, from which water flows through downcomers 12 to a drum 14 leading upwardly from which are rows of steam generating tubes forming in part the walls of a radiant chamber 16. The unit also comprises. wall tubes 22, header 24, riser wall tubes 26 and a header 28 connected to the drum 10. Tubes 30 lead from the drum 14 along a floor 32 and wall components 36...38 which separate cyclone furnace chambers 42, 40, from the secondary furnace chamber 34 and form furnaces throats 44, 46, and finally extend as risers 54 to the drum 10. Tubes 60 extend from the drum 14, first in widely spaced relation through screens 62, 64 and then as the basis of a refractory covered wall 66 and roof 68 before connecting to the drum 10 through riser tubes. Similar arrangements of steam generating furnace wall tubes are included in the furnace side walls. Upwardly of the header 24 all chamber walls, with the exception of inclined wall 52, are lined with tangent superheater tubes 70, 76, 78, 80, Figs. 1, 2, the superheater tubes being supported by the steam generating tubes in such manner as to allow of independent movement therebetween (see Group XII). The upper part of chamber 16 is sub-divided by spaced reheater (82, 84, 86, 88, Fig. 2) and secondary superheater (83, 85, 87, 89) tube platens parallel to the side walls 72, 74. Each reheater platen consists of pendant U-tubes having a downflow leg 90A, Fig. 3, leading from a suspended header 90B and an upflow leg 90C connected to a suspended header 90D. The superheater platens are similar. The steam generating tubes 92, Fig. 3, of the side wall 72 are connected to a suspended header 94 whilst the superheater tubes 70 are U-tubes having inlet and outlet legs 70A, 70C, leading to respective suspended headers 70B, 70D. The roof of chamber 16 includes secondary superheater tubes 100 connecting to a header 102 through tubes 80. The cyclone furnace walls include tubes connected to headers such as 106 and risers 108 which form platens 110...114, Fig. 2, and terminate at the drum 10. The convection section of the unit is divided by a wall 114A, Fig. 2, into a reheater gas pass 110 and a superheater gas pass 112 the latter comprising secondary and primary superheaters 116,118. The passes 110, 112, lead to economizer sections 122, 124. Specifications 526,825 and 598,142 [Group XII] are referred to.