78 All About Engines
casing with firebrick lining. The marine type is often
used for land purposes. It can be made in smaller parts
which are more easily transported to places which are
Half Section Front View.
Fig. 44.—Diagrammatic view of three-drum boiler
A, Ashpit; B, Firebars; C, Furnace; D, Water Drum; E, Steam Drum; F Superheater;
G, To Funnel
not served by railways, where roads are bad, and where
appliances for lifting heavy weights are not available.
The next type of boiler to be described is the
Yarrow, or three-drum boiler, and is used only on
ships, for which it is specially designed. In its