St. Paul daily globe., 1893-10-22

idea is certainly worth an experiment.
The Society for the Prevention of Smoke
might do well to look into the matter.
Many steam users have claimed that it
is impossible to burn soft coal and make
no smoke. Many devices have been in
troduced, and some apparently worked
satisfactorily in this direction. But
when the question was put to Prof.
Schwackhoefer i'll conversation he
stated that ne did not think there was
any practical way of preventing smoke,
as all devices had proved more or less
deficient, or had drawbacks that made
their general use impracticable. Dust
fuel, in his opinion, is the only absolute
preventative that entails no sacrifice on
the part of the steam user.
In this connection some statements
from report published some time ago,
in technical paper in Germany, may
be OF interest. At meeting of the So
ciety for the Treatment of Steam Boil
ers of Magdeburg. Germany, a paper
was read in which the lecturer stated
that while the idea of firing with pull
verified fuel was not new, it had never
until lately been put into practice A
Berlin firm of engineers had made ex-
perlmentS of which some results were
available. Accordingly coal is put into
large hopper, or feeder. at the bottom
of which is a shaking plate, which de-
l'vers the coal dust in even quantities
into tube through which air is blown
by ian into the fire chamber. The
current of air carries the coal
along and enters the chamber
IN condidltion of intimate mkt
ure with the fuel. The chamber is
lined with fire brick and its red-hot
walls keep setting the mixture on IRE
as 1t enters. Combustion proceeds rap
laly. completely, and at the highest
temperature The amounts of coal and
air can be readily adjusted to one. an
other and to the work required. Under
the influence of the high temperature
the fine particles of ashes are fused
and flow together at the bottom of the
chamber. remaining in fluid condition
until drawn off. The fire may he in
terrupted by merely turning off the
fan, and after the lapse of hours if the
fre Is to be started it is sufficient to turn
on the fan, where the fire chamber hav-
ing remained hot will ignite the fuel as
1t Is blown in. the smoke. of course,
Is easily and completely consumed. that
is, there is no smoke or SCOT formed.
OBJECTIONS TO THE FUEL.
The objections made to the use of coal
dust, pending more extensive expert.
mentS. are these: The grinding of the
coal is thing of questionable practical
btllty where large quantities are EN-
ployed. Difficulties may arise in firing
up after long periods of rest, such as
over night. There can be no banking
of the fire. AS to the great saving
claimed, the coal grinder aud ventilator
lanS create new sources or expense.
The Hamburg-American Packet COM
pany recently made extensive expert
mentS i'll this direction, but found the
expense of grinding the coal too great to
compensate for the savings III other
ways. The only way i'll which coal
could be ground economically would
probably be to have it done right at the
mine and on large scale.
Another objection, and serious one,
Is the danger of using coal dust. This
material in exceedingly fine condition
is highly. explosive. Under the influ-
ence of heat there is always more are
less dry distillation, and the gases re-
qulre no open blaze. but only heat, to
ignite them. The dust being infinitely
more inflammabe than lump coal would
easily catch fire if the gases given off
by dlstillatiOn should ignite. A similar
danger might exist in the furnace.
The action of the fan hot being power
fui enough to keep up an uninterrupted
strong current of air and fuel into the
fire chamber the blaze might work back
through the fuel supply tube and reach
the feeder or the place where the coal
dust is stored, causing explosions and
destructive fires. On the other hand,
the work would be cleaner. easier and
prompter, and the owner would be
somewhat more independent of the
fireman. ''- --r.
The statement that even a smokestack
is not required where dust fuel is used
probably rests on a similar argument as
the one that loss of heat in firing has
been placed to the credit of imperfect
combustion, the smoke being visible,
while the principal source of loss. the
excess of air, is invisible. There GER
talnly must be aaOutlet for the products
OF combustion, the various carbonic
oxides, all of which are more or less in
furious to the human system. and
should he carried off in some manner.
Not being visible, these agents may nave
been overlooked in the consideration
that there was no black smoke tnat re-
Qulred chimney.