GB1265662A - - Google Patents

Abstract

1,265,662. Marine boilers. BABCOCK & WILCOX Ltd. 22 Sept., 1969 [23 Sept., 1968], No. 45198/68. Heading F4A. A vapour generating and superheating unit in a ship propulsion plant, Fig. 1, comprises a furnace chamber 12, a first gas pass 43, Fig. 5, having superheater sections 56, 53 and a second gas pass 44 having superheater sections 71, 62 and reheating means 59, both passes being arranged for the parallel flow therethrough of combustion gases, the superheater sections 56, 71 being arranged for serial flow of vapour before it is cooled in attemperating means 78, while sections 53, 62 are arranged for serial flow after cooling in the attemperating means, and dampers 74, 75 controlling gas flow through the two passes. The attemperating means 78, arranged for parallel flow of steam, are contained in a separating drum 17 together with desuperheating means (79), Fig. 2 (not shown), arranged for serial flow of steam. The furnace chamber 12 fired by oil burners 23, has tube walls 18, 26 (31), Fig. 4 (notshown), and 11, the latter tubes of which defining an upflow passage 13 for combustion gases, which is divided into the passes 44, 43 the upper part of pass 43 housing economizers 45. Tube walls 18, 26 each extend between a header 15 and the drum 17 while tube wall (31) extends between headers (33) and the drum 17 via headers 34. The passage 13 has tube walls which each extend between headers 37, (38), Fig. 3 (not shown), and then to the drum 17. To drive the ship ahead, steam is generated for the high-pressure turbine of the main turbine system and the dampers 74, 75 and a three-way valve 80 are adjusted, so that the reheater 59, reheating steam between stages of the turbine system, and attemperator 78 result in the steam temperature at the high-pressure turbine being at the desired level. In astern operation dampers 75 are closed, since the reversing turbine does not require reheated steam, and valve 80 adjusted to ensure steam at the desired temperature reaches the turbine.