GB799064A - Improvements in steam generating and steam heating installations - Google Patents

Abstract

799,064. Water-tube steam boilers; regulating steam temperature. BABCOCK & WILCOX, Ltd. Oct. 11, 1956 [Oct. 24, 1955], No. 30972/56. Classes 123(2) and 123(3) A steam generating and heating installation comprises two similar boiler units 10, 12 spaced apart lengthwise of a common steam and water drum 14. The unit 10, which is shown in Fig. 2, comprises an upright furnace 56 lined with steam generating tubes extending between lower headers such as 44, 92 and upper headers such as 74, 98 which are respectively connected by downcomers and circulators to the drum 14. Combustion gases flow from the upper part of the furnace between the platens of a secondary superheater section 182 into a lateral pass locating another secondary superheater section 188 and a primary superheater section 190 and then flow downwards in a pass 192 in which are disposed other primary superheater sections 194, 195, 196 and economiser tube banks 200, 202. Provision is made for recirculating flue gas for steam temperature control, a fan 208 withdrawing the gas from the bottom of the pass 192 and discharging it into the bottom of the furnace 56. The unit 12 is identical except that the secondary superheaters 182, 188 are replaced by reheaters. In order to minimize the path of travel of water longitudinally of the drum 14 and to give an equalizing effect upon temperature along the drum and upon the fluid circulation of the units 10, 12, the downcomers and circulators are cross-connected as shown in Fig. 1. The downcomers 18, 19 of the unit 10 are connected to the drum 14 at points opposite that unit and at points 26, 38 opposite the unit 12 by branch pipes 24, 36; the downcomers 20, 21 of the unit 12 are connected to the drum 14 at points opposite the unit 12 and at points 30, 34 opposite the unit 10 by branch pipes 28, 32. In a similar way the upper collector headers of each unit are connected by circulators to the adjacent and remote parts of the drum so that the two units are tied together in a single circulatory system. Specification 526,825 is referred to.