IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES AND THEIR FLUES FOR THE PREVENTION OR CONSUMPTION OF SMOKE
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by James Campbell and Francis
Gemmill at the Office of the Commissioners of Patents, with their
Petition, on the 30th May 1874
We, JAMES CAMPBELL and FRANCIS GEMMILL, both of Paisley, in the
County of Renfrew, North Britain, Engine Keepers, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN THE CONSTRUCTION
OF FURNACES AND THEIR FLUES FOR THE PREVENTION OR CONSUMPTION OF SMOKE,"
to be as follows:-
.
The nature of this said Invention consists in erecting a set or pile of
fire-clay or other pipes which will resist the heat of the fire over each
other and the bridge wall at the back end of the furnace, stretching
horizontally behind it, resting on this wall and others erected for the
purpose within the back flue, filling the space to the top so as to form
long flue red-hot pipes for the whole smoke and flames to pass through
just after escaping from the fuel and back end of the furnace, or fire-
grate, or box; and also in forming air openings, channels, or pipes
through from the lower part of the ash-pit and the back or bridge wall
below the furnace bars, which would conduct sufficient air therefrom

page_text: .
into a recess in or behind that wall or one of the other walls
carrying the stack of flue pipes, up either at their front or back end so
as to inflame or intermingle or burn along with the gaseous products of
combustion from the fuel and furnace as they are entering or passing
from these flue pipes so as to completely consume them and prevent the
formation or escape of black smoke which is really utilized in producing
flame, and therefore effecting a saving in fuel. The air so admitted from
the ash-pit to these recesses is preferred to be regulated by a door or
valve, and spread in a thin current across the whole flue at the front or
back ends of the flue pipes, which may either simply rest on each other
or on separating supports, end to end, when made in short lengths, as
two or more, when made in three feet lengths, all so as to become red
hot or as hot as the air and gases require to be to burn in passing
through these flue pipes; and in tubular boilers these flue pipes might
be made shorter and stacked or piled as stated in front of the ordinary
flue heating tubes, which are kept too cold by the water in the boiler to
keep the gases and air at the said high heat for their complete com-
bustion, and from their coldness forming and taking on a coating of soot
on their heating surface, which prevents the absorption or radiation of
the heat from the said gascous products of combustion, and which is in
a great measure prevented by these improvements, thus not only pre-
venting the escape of the smoke from the furnace and chimney, but
also effecting a saving in fuel and giving a better heating effect and
radiation by keeping the heating surface of the boiler cleaner.
а
The new hot flue pipes may be of any ordinary size or sectional shape,
as from three inches and upwards, and round, oval, or polygonal. Six-
sided pipes would suit well, as they fit into each other without
interstices. When the pipes are round with interstices between them
the air could be admitted at the middle parts of the pipes, when desired,
instead of at the ends only.