Page 91 - Introduction to Marine Engineering

78 Boilers

Inlet heater
Cast iron gilled section

Sootblower

Upper front water wall
header-furnace side

Lower front water wall
header-furnace ride
Sootblower
Water drum
Downcomers wer front water wall
header-superheater side
Figure 4.4 Foster Wheeler Type ESD III monowall boiler

by infra-red radiation. This usually requires roof firing and a
considerable height in order to function efficiently. The ESD IV boiler
shown in Figure 4.5 is of the radiant type. Both the furnace and the
outer chamber are fully watercooled. There is no conventional bank of
generating tubes. The hot gases leave the furnace through an opening at
the lower end of the screen wall and pass to the outer chamber. The
outer chamber contains the convection heating surfaces which include
the primary and secondary superheaters. Superheat temperature
control is by means of an attemperator in the steam drum. The hot
gases, after leaving the primary superheater, pass over a steaming
economises This is a heat exchanger in which the steam—water mixture