4 APPLICATION OF THE LAWS OF HYDRAULICS
First Experiment.—Study of the older, or updraft, type of
brick kiln (Fig. 1), which has the opening for the escape of the
waste gases at the highest part of the arched roof.
Small streams of colored kerosene are introduced through the
fireboxes and flow up to the central orifice, which is wide open.
The streams of kerosene may be seen as fine threads flowing up
close to the walls of the kiln and are not of sufficient volume to
fill the kiln chamber. Increasing the flow of the kerosene, or, as
it may be expressed, firing the kiln more heavily, does not affect
the result, It is very clear that the burning of the brick in a
kiln working in this manner will be defective. The brick in the
lower portion of the kiln will be soft and only partially burned.
In order to improve this condition it will be necessary partially to
stop up or close the smoke hole. The poor working conditions
which exist in the updraft brick kiln are shown in Fig. 1. When
the smoke hole is partially closed, the kerosene is forced to accumu-
late in the upper portion of the kiln; it fills more and more of the
the surface of the water; thence by a trough it flows to the large bottle below.
A small pump driven by a motor of -^ hp draws the kerosene from the lower
bottle and delivers it to the upper bottle, enabling the kerosene to circulate
by gravity as long as desired.