purpose. They are tack-welded in place and can be
removed when you are installing the new liner. If they
are not removed, make sure the liner has clearance
between this clip and the end of the refractory to allow
for expansion in this direction.
Depending upon the design pressure of the boiler,
the furnace may be of the corrugated type. Although it
is not necessary to fill in the depressions for
convenience of installation, some or all of the
corrugation valleys may be filled with insulating
cement. The liner tile should be fitted tightly against
the crown of the corrugations.
The furnace extension of the boiler or a dry oven is
shown in figure 2-21. The throat tile should be installed
flush with the front of the oven and should fit tightly
against its sides. The two rows of furnace tile should be
fitted tightly against the furnace wall. It is not
necessary to allow for expansion.
It is recommended that the tile be dry fitted, match
marked, removed, and then reinstalled with the proper
amount of refractory cement. Thin joints are desirable.
Generally, it is necessary to shave a portion from one
or more tiles to obtain a fit. If a fill piece is required, cut
it to fit and install this piece at the bottom of the
furnace. It is important to have a good seal between-the
burner housing and the throat tile. Liberally coat-the
sealing area with an insulating pulp cement or
equivalent mixed with water before swinging the
burner housing into place.
The rear door is a steel shell containing horizontal
baffle tiles and lined with insulation material and a
castable refractory (fig. 2-19).
Burned or discolored paint on the outer surface of
the door does not necessarily indicate refractory
trouble but may be an indication of other conditions
such as the following:
Door retaining bolts insufficiently or unevenly
Air line to the rear sight tube is blocked or loose.
Figure 2-21.Furnace liner refractory125-150-200 hp.