The Flow Of Gases In Furnaces

DESIGN OF OPEN-HEARTH FURNACES

271

bers for gas and air. When properly laid to secure stability, the
9-in straight makes a checker with the maximum heat storage
utilization of the volume occupied.

All of the computations are based upon an assumed rate of
fuel consumption, and will vary as that rate changes. Other
variations will be introduced by the use of different fuels and
different working conditions, than those which were fixed initially
as a basis for the computa-
tions. However, there is no
basic reason why the design
of a furnace cannot be reduced
to rational methods. When
the method of operation and
the design are fixed, it is

possible to predict the fuel ^ __ -- xu , , _ .

^ . , . FIG. 166. — Method of Laying Up

consumption within a reason- Checker Brick to Form Vertical

able margin, as well as the Passes.

performance of the furnace as

a heat-transfer apparatus. The main difficulty in obtaining

accurate results with these computations—results which will

check with practice—lies not in the computations, but in the

Waste
1
— P. 1 I

M

Heat
----

Boiler
1

i

"Damper
Fan

FIG. 167.—Schematic Arrangement of Flues and Dampers with
Waste-heat Boiler.

initial assumptions, for unless the foundation is. true the entire
superstructure will be wrong. For instance, in computing the
heat losses from the exterior walls of the furnace and chambers,