PRINCIPLES OF NAVAL ENGINEERING 



DRUM SAFETY VALVES 



ECONOMIZE!! INin 



STEAM DRUM 



SCRUBBEI! ELEMENT 



SURFACE BLOWOFF PIPE 



CYCLONE STEAM SEPARATOR 

 INTERNAL FEED PIPE 



STEAM COLLECTING BAFFLE 



AIR INLn TO V 

 DOUBLE CASING \ 



MODEL IN SOOT BLOWER 



STEAM DRUM 

 PROTECTION PLATES 



SUPERHEATED-SIDE 

 FURNACE 



FURNACE PEEP HOLE 



SOOT BLOWER 

 ELEMENTS 



HIGH TEMPERATURE 

 INSULATING BRICK 



STUD TUBE 

 WATER COOLED 

 SIDE WALL 



PLASTIC CHROME ORF 

 DOWNCOMER 



WATER WALL HEADER 



IMPELLER PLATE 



DENSE FIREBRICK 



HIGH TEMPERATURE 

 INSULATING BRICK 



UNCALCINEO DIATOMACEOUS 

 EARTH BLOCKS 



BRICK BOLT 



WATER SCREEN HEADER 

 PROTECTION PLATES t BAFFLE MIX 



SeECIAl OIL BURNER LIGHTING PORT 

 AIR LOCK TYPE 



SATURATED-SIDE 

 FURNACE 



SUPERHEATER 

 TUBE SUPPORTS 



BURNER, BEADED 

 CONE 



WATER DRUM 



BOTTOM BLOWOFF 

 CONNECTION 



WATER WALL HEADER 

 DRAIN CONNECTION 



PLASTIC CHROME ORE 



WATER SCREEN HEADER 



BLOWOFF CONNECTION DOWNCOMERS 



BURNER AIR DOORS 

 FUEL OIL BURNER 

 FURNACE ACCESS DOOR 



STDNTUBE WATER-COOLED 

 DIVISION WALL 



SM- 



38.38X 



Figure 10-19.— Double-furnace boiler (cutaway view). 



furnaces— one for the saturated side and one for 

 the superheater side. It has controlled superheat. 

 It operates at a pressure of about 615 psig, and 

 is often called a "600-psi boiler." 



The most important advantage of the double- 

 furnace boiler arises from the fact that the 

 separate firing of the superheater side allows 

 positive control of the degree of superheat. In 

 the double-furnace boiler, it is theoretically 



possible to maintain the maximum designed 

 temperature at the superheater outlet under 

 widely varying conditions of load. In a single- 

 furnace boiler, where one source of heat is used 

 both for generating the steam and for super- 

 heating it, the degree of superheat increases 

 as the rate of steam generation increases; and 

 hence the maximum designed temperature at the 

 superheater outlet is normally reached only at 

 full power. 



250 



