GB737200A - Improvements in tubulous vapour generating and vapour heating units - Google Patents

Abstract

737,200. Water-tube steam boilers; steam superheaters. BABCOCK & WILCOX, Ltd. Dec. 18, 1953 [Dec. 23, 1952], No. 32676/52. Classes 123 (2) and 123 (3). A water-tube steam &c. boiler especially for marine use has two furnace chambers 1, 3 lined with refractory covered steam generating tubes and fired respectively by burner groups 8, 12 through ports 7, 9 in the front wall of the unit, the gases from furnace 1 discharging laterally through a screen 47 of generating tubes into parallel gas passes 13, 15 separated by a passage. way 17 and leading to a common uptake 19 in which is disposed an economizer 20. The gas flow through each pass 13, 15 is controlled by dampers 21 at their respective outlets into uptake 19. The passes 13, 15 locate respectively the sections 25 and 27 of a convection steam generating tube bank 23, the tubes of which extend between a water drum 31 and a steam and water drum 29, the latter also receiving the output from the furnace lining tubes which extend from lower headers 75 and 115. Between the screen 47 and the tube bank 25, pass 13 locates a superheater 33. The gases from furnace 3 also discharge laterally through a screen 60 behind which is disposed a reheater 53, the gases, after traversing the reheater, flowing through passageway 17 into a turning space 151 which serves to direct them into pass 15 and thence to uptake 19. During normal operation, both furnaces are fired, the steam output and reheat temperature being respectively regulated by adjustment of the firing rate of burners 8, 12 whilst the superheat temperature is regulated by control of dampers 21. During manoeuvring, furnace 1 is worked to give a substantial output of steam with little or no superheat whilst furnace 3 and reheater 53 are inoperative, the safety of the reheater being ensured since it is screened from furnace 1 and is not subjected to gas flow. During starting, furnace 1 only is fired, dampers 21 of pass 13 being closed to prevent damage to the superheater. In modified forms of the unit (Figs. 5-9, not shown) furnaces 1 and 3 are disposed side by side, the gases from furnace 3 flowing into furnace 1 after passing through a screened reheater.