HOT-BLAST TEMPERATURE EQUALIZERS
more openings; the total area of these openings may be arrived
at by the use of the formula given in an earlier chapter of this
work, for furnaces having an orifice in the roof for the escape of
the waste gases.
If the area of these orifices and the volume of the combustion
chamber are correctly proportioned, the combustion pits of the
Cowper stove will be completely filled with the burning gases,
which will be held in the combustion chamber by reason of the
strangulated outlet, until the reaction of combustion is completed.
The free space below the dome of the stove will cease to play the
part of a combustion chamber, and it will become possible to carry
the checkerwork up higher into the dome of the stove.
IV. HOT-BLAST TEMPERATURE EQUALIZERS
It is not difficult to show that the construction of a rational
apparatus for the equalization of hot-blast temperatures is not
Fig. 75 shows the general arrangement of such hot-blast
equalizers as have been constructed.
Assuming that the temperature of
the blast is higher than that of the
brickwork in the equalizer, the
branch A, in which the hot gases
rise, will work irregularly, whereas
the branch B, in which the hot gases
pass downward, will be heated uni-
formly. The branch A will not heat
in a satisfactory manner; the branch
B will heat in a satisfactory man-
Assuming that the temperature
of the hot blast drops below the
temperature of the brickwork, the
branch A will commence to cool
uniformly and rapidly, whereas
the branch B will cool irregularly and slowly.
No one has been able to obtain satisfactory results from the
use of hot-blast temperature equalizers, and for this reason they
are very rarely used.