| 摘要 |
956,474. Regulating steam temperature in boilers; recirculating combustion gases. BABCOCK & WILCOX CO. Jan. 20, 1961 [Jan. 25, 1960], No. 2401/61. Headings F4A and F4B. In a high capacity high pressure and temperature natural circulation boiler including upright vapour generating wall tubes 18, 22, 27 lining a furnace chamber 12A, 12B, 12C low temperature gases, e.g. to control slanging and regulate steam temperature, are introduced into the radiation section 12A of the furnace chamber through a duct 52 the front face of which is defined by water-cooled rear wall tubes 22 which, at places, are displaced outwardly and laterally within the duct 52 to form low pressure drop outlet passages 56A, 56B and provide a shield which protects the inner face of the duct against radiation. Groups of adjacent tube parts 22A-22H are located, at spaced intervals, longitudinally of the duct 52 and as shown in Figs. 2, 3 the tubes of each group comprise tube sets 22A-22D and 22E- 22H which fan outwardly in a curve from opposite sides of a centre port 56 baffles 59, e.g. closely spaced flat studs 60 welded to the tubes and appropriately shaped plates, closing the spaces 58 between the tubes 22A-22H to form the streamlined outlet passages 56A, 56B. A retractable soot blower 61 is located at each port 56 the groups of which may be located at any desired position in the furnace chamber walls. The low temperature gases are withdrawn from a down pass 14 through a duct 49 leading to a blower 50 which discharges into the duct 52. Superheater tubes, lining the roof and walls of the downpass, are connected to a primary superheater 39 arranged upstream, gaswise, of an economiser 46 in the downpass 14 and connected to a secondary superheater 43 arranged in a horizontal pass 13 in front of a reheater bank 70. Cyclone furnaces 20, 20A, arranged at different levels and having their barrel portions defined by steam generating tubes, discharge into the section 12B of the furnace chamber. Other burners may be used for firing the unit. Specification 552,747 is referred to. |
