IMPROVEMENTS IN FURNACES, ASH-PITS, AND FLUES FOR THE CONSUMPTION OF SMOKE AND NOXIOUS PRODUCTS OF COMBUSTION, AND IN THE APPARATUS OR MEANS CONNECTED THERE- WITH
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by James Robertson at the Office of
the Commissioners of Patents, with his Petition, on the 6th January
1865.
I, JAMES ROBERTSON, of Glasgow, in the County of Lanark, North Britain,
do hereby declare the nature of the said Invention of "IMPROVEMENTS IN
FURNACES, ASH-PITS, AND FLUES FOR THE CONSUMPTION OF SMOKE AND NOXIOUS
PRODUCTS OF COMBUSTION, AND IN THE APPARATUS OR MEANS CONNECTED THERE-
WITH," to be as follows, that is to say :-
This Invention relates to certain improvements in the construction and
arrangement of furnaces, ash-pits, and flues, the chief objects of which are
to consume the smoke and other noxious products arising from combustion,
together with a large saving of fuel.
According to one modification it is proposed to have an air-tight door in the
ash-pit, with an orifice formed in it, into which a tube is inserted leading from
fanners or other apparatus for forcing or drawing air into the ash-pit, thence
up through the fuel and along the flues. Instead of this arrangement per-
forated tubes may be introduced into the ash-pit near the fire-bars, and are
forced up through these perforations into the fuel and flues, and perforated
tubes may also be introduced into the furnace, and so arranged in it that when
the air is forced into the tubes it acts upon the burning fuel in small currents
by passing through the perforations. When there are a number or series of
furnaces the smoke and other volatile products are brought together into
one flue or passage, and then passed over or through highly heated surfaces;
and when the smoke or gases are in a highly heated state, air is admitted for

page_text: their abatement in consumption. Instead of this last-mentioned arrangement
it is proposed to place a box below the furnace bars, constructed so that the
front part may be lowered in order that the ashes may be discharged. This
box may be either open on the top or be fitted with a perforated cover; it has
an opening or perforations in the front through which the air is forced, thence
up through the fuel and along the flues.
When locomotive engines are travelling the currents of air forced in
through the openings in the ash-pan are sufficient to force the air through the
fire and flues. When it is desired to kindle fires for the purpose of getting
up steam in locomotive, steamboat, and other boilers, it is proposed to employ
fanners or other suitable means, from which a tube is lead into the ash-pit,
fire-bars, fire-box, or into the tubes, forcing air in, by which the steam is got
up very quickly. It is found that by forcing air by mechanical means through
the fuel and flues that the flues may be extended by repeatedly returning
them through the boiler, thus giving a larger surface, whilst at the same time
the heat is retained to a much larger extent then at present in the furnace
and flues, this being regulated by the control which the fireman has over the
pressure of the admitted air, the pressure being regulated by a stop-cock or
other suitable means; this latter arrangement may also be made self-acting.
Another part of this Invention consists in covering over the upper part of a
boiler (which is generally exposed) with a material of low conducting powers
leaving a space between the boiler and the covering, thus forming a duct or
flue through which the air is allowed to pass from an opening made at that
part of the flues furthest from the furnace door, at which latter point the air is
forced in, whence it travels along between the boiler and covering to the front
end of the furnace at this point, an elastic or other tube is fixed and leads to
an orifice in the top of the furnace door. The door is by preference made
hollow and open at the bottom, where the air is forced through an opening in
the dead plate into the ash-pit (an air-tight door closing the ash-pit). And
the air being heated in its progress has no other outlet but between the fire-
bars through the fuel and flues, thus the heat radiating from the boiler,
furnace door, and ash-pit, is carried through the fire and flues without being
lost. In some furnaces the fire-bars instead of being made of metal may be
constructed of fire-clay, hollow and perforated, and the air is then forced
through them at the opening in the front whence it passes up through the
perforations into the fuel and along the flues.
In all the different modifications berein-before referred to, the furnace man
has complete control over the supply of air, can regulate the draught to what
may be required, and retain the heat in the furnace and flues, thus tending to

page_text: generate steam and save fuel. By the existing systems great loss ensues from
a large portion of the heat passing away into and up the shaft. According to
the present Invention no tall shaft is required, as the fireman at all times can
command a draught to what may be required by regulating the supply of air
'forced in.