Figure 4-1.—Cutaway view of a D-type boiler.
add each part to your boiler, follow the line
drawings introduced in the following paragraphs
that describe the position of each component.
STEAM DRUM
The steam drum is a cylinder located at the
top of the boiler. It runs lengthwise (fig. 4-1) from
the front to the back of the boiler. The steam
drum provides a space for the saturated steam
generated in the tubes and for the separation of
moisture from the steam. (Remember, saturated
steam is steam that has not been heated above the
temperature of the water from which it was
generated). The steam drum also serves as a
storage space for boiler water, which is distributed
from the steam drum to the downcomer tubes.
During normal operation, the steam drum is kept
about half full of water. The steam drum either
contains or is connected to many of the important
controls and fittings required for the operation
of the boiler.
At the bottom right side of the boiler you will
find the water drum, and on the bottom left side
4-5
