GB731311A - Improvements in or relating to steam generators - Google Patents

Abstract

731,311. Water-tube steam boilers. INTERNATIONAL COMBUSTION (HOLDINGS), Ltd. (Combustion Engineering Superheater, Inc.). Feb. 16, 1953, No. 4322/53. Class 123 (2). A water-tube steam boiler has a furnace A fired by downwardly directed burners 8 mounted in the roof of an offset chamber 1a in the furnace front wall 1. Combustion gases from the burners flow downwardly in chamber 1a and upwardly in the furnace A, discharging through a lateral pass 7 in which is disposed a superheater S and then turning for. downward flow through a flue 10 locating an economizer E, the gases passing to an outlet 11 through an air heater AH. The front wall 1, side walls 3 and roof 4 of the furnace are lined with steam generating tubes 16 which extend from a lower header 23 to header 25a which is connected to a steam and water drum 17. The rear wall is lined With, superheating and reheating tubes arranged as shown in Fig. 3, two groups of downflow superheater tubes 32 carrying steam from drum 17 being arranged alternately with upflow tubes 33 through which the steam flows to a header 35 and thence through superheater S to the final outlet header 40 whilst the reheater tubes extend from a lower header 42 between the groups of superheater tubes to an outlet header 43. To avoid excessive metal temperature of the steam heating tubes, chamber 1a is divided into separate compartments by vertically disposed banks of steam generating tubes which provide additional heat absorbing surfaces for the furnace A and ensure a safe temperature particularly in the lower portion thereof whilst allowing a high combustion rate to be maintained. The boiler may be operated with natural circulation or with forced circulation in which case a pump 55 delivers water from drum 17 to the lower header 23.