The Flow Of Gases In Furnaces

58 APPLICATION OF THE LAWS OF HYDRAULICS

dimensions of the furnace heating chamber are affected (Fig. 36),
but the level of the lower free surface of the stream of gases remains
at the hearth of the furnace, and the furnace continues to work
well. The gases, however, remain in the heating chamber a
longer time and a better transfer of their heat to the material
being heated is obtained. The temperature of the gases leaving
the furnace and, accordingly, the temperature of the material
being heated, are different.

In this manner it is not difficult to pass from the consideration
of the continuous or gradual reheating furnace to that of the
chamber type of furnace. Fig. 37 shows a type of furnace inter-
mediate between the ordinary reheating furnace and the chamber

FIG. 37.
type of furnace. This is a reheating furnace at the Pouliloff
works; it is very short and has a high roof permitting very large
ingots to be placed upon its hearth.
Figs. 38 and 39 show the arrangement of a kiln for the burning
of silica brick, designed by the author. This is a multiple-chamber
furnace (Siemens system); the gas and the air enter and the prod-
ucts of combustion leave the heating chamber at the hearth level.
The hot products of combustion rise to the roof of the chamber,
and, as they gradually lose their heat, descend towards the hearth
and then pass through the flues leading to the regenerators. The
furnace chamber is constantly filled with flame, and the hearth
is always in contact with the hot gases. The design may be