IMPROVEMENTS IN THE CONSTRUCTION OF BOILER FURNACES FOR ECONOMIZING FUEL AND PREVENTION OF SMOKE
Year: 1878

page_text: LETTERS PATENT to Francis William Ashton, of Manchester, in the County of
Lancaster, for the Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF
BOILER FURNACES FOR ECONOMIZING FUEL AND PREVENTION OF SMOKE."
ealed the 25th June 1878, and dated the 16th April 1878.
PROVISIONAL SPECIFICATION left by the said Francis William Ashton at
the Office of the Commissioners of Patents on the 16th April 1878.
"
FRANCIS WILLIAM ASHTON, of Manchester, in the County of Lancaster. ."IM-
PROVEMENTS IN THE CONSTRUCTION OF BOILER FURNACES FOR ECONOMIZING FUEL
AND PREVENTION OF SMOKE."
...This Invention relates to the construction of..the furnaces of steam boilers so that
there is a chamber. or second furnace behind the first furnace to receive the partly
burnt. fuel which is pushed forward from the first furnace, and through which a
current of air, steam, or gas is caused to pass, either by the natural draught or
otherwise, so that the fuel in this second furnace is kept constantly in an incan-
descent state, and every. combustible. part of the fuel is thus entirely consumed;
at the same time that any smoke produced by the fresh fuel in. the first furnace
having to pass over the incandescent mass in the second furnace will be ignited and
entirely consumed also.
In carrying out my. Invention, I dispense entirely with. the usual bridge and also
with the bridge wall beneath which ordinarily divides the ash-pit from the back
part of the flue. For this latter I substitute a cast-iron frame or partition fitted
with a damper or door which can be opened or closed to any desired extent from.
the front. At. a small distance behind the ends of the fire-bars I fix an inclined
slope made of cast iron or fire-brick, the upper side of which is about level with the
fire-bars (or rather higher), and the lower side fits the lower half of the flue. and
slopes forward towards the cast-iron frame or partition above. named, the space
between this partition and the cast-iron or fire-brick slope forming the chamber.or
second furnace above mentioned.

page_text: The stoker does not rake out any of his fuel forwards as usual, but before sup-
plying fresh fuel he pushes the fire back, and a quantity of this burning fuel falls
over the end of the furnace bars into this chamber and partly fills it. The stoker
then opens the door or damper in the ash-pit, and, the air being admitted, passes
through and keeps the fuel in an incandescent state, whereby all the combustible
part thereof becomes entirely consumed, leaving nothing but ashes and clinkers.
The intense heat thus produced in the second furnace entirely consumes any smoke
from the fresh fuel in the first or outer furnace as it passes over the same on its
way to the flue.
The ashes and clinkers from this chamber or second furnace can be raked
out from time to time, as may be required, through the door or damper in the
ash-pit.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis William Ashton in the Great Seal Patent Office on the 14th
October 1878.
"
FRANCIS WILLIAM ASHTON, of Manchester, in the County of Lancaster. ''IM-
PROVEMENTS IN THE CONSTRUCTION OF BOILER FURNACES FOR ECONOMIZING FUEL
AND PREVENTION OF SMOKE."
This Invention relates to the construction of the furnaces of steam boilers so that
there is a chamber or second furnace behind the first furnace to receive the partly
burnt fuel which is pushed forward from the first furnace, and through which a
current of air (steam, or gas) is caused to pass either by the natural draught or
otherwise, so that the fuel in the second furnace is kept constantly in an incan-
descent state, and the combustible part of the fuel is consumed; at the same time
that any smoke produced by the fresh fuel in the first furnace having to pass over
the incandescent mass in the second furnace will be ignited and consumed also.
Such being the nature and object of my said Invention, I will now proceed to
describe in detail the manner in which the same is to be or may be performed or
carried into practical effect; and in order that the same may be clearly understood,
I have annexed hereunto a Sheet of Drawings illustrative thereof, and have marked
the same with figures and letters of reference corresponding with those in the following
explanation thereof.
In the annexed Drawing, Fig. 1 is a longitudinal section, and Fig. 2 a transverse
section of a boiler flue fitted with my Invention; a, a, being the flue; b, b, the
"dead plate;" and c, c, the ordinary fire-bars, which may either be laid horizontally
or sloping slightly backwards, as shown at Fig. 1.
In carrying out my Invention, I dispense entirely with the usual bridge and also
with the bridge wall beneath, which ordinarily divides the ash-pit from the back
part of the flue. For this latter I substitute a cast-iron frame or partition d, d,
made in the form of a flat arch, and, if required, fitted with a damper or door which

page_text: can be opened or closed to any desired extent from the front, as shown by dotted
lines. This cast-iron frame d, d, supports a block e, e, of fire-clay, which protects
the rear end of the fire-bars from the great heat, this block being so formed (see
back view, Fig. 3) that the air entering by the arch must pass through the incan-
descent fuel at the same time that it is distributed over the whole width (or as
nearly so as possible) of the flue. At a small distance, say, from one to two feet
behind the ends of the fire-bars c, c, I fix an inclined slope f,f, made of cast iron
or fire-brick (the latter by preference), the upper side of which is curved and about
level with the fire-bars (or rather higher), and the lower side fits the lower half of
the flue a, a, and slopes forward towards the cast-iron frame or partition d, d, above
named, the space between this partition and the cast-iron or fire-brick slope ƒ, f,
forming the chamber or second furnace above mentioned.
The stoker does not take out any of his spent fuel forwards as usual, but before
supplying fresh fuel he pushes the fire back, and a quantity of this burning fuel
falls over the end of the furnace bars, over the block e, e, into the chamber and
partly fills it, and the air being admitted passes through and keeps the fuel in an
incandescent state, whereby all the combustible part thereof becomes entirely con-
sumed, leaving nothing but ashes and clinkers. The intense heat thus produced in
the second furnace, together with the air admitted, as above stated, consumes any
smoke from the fresh fuel in the first or outer furnace as it passes over the same
on its way to the flue.
The ashes and clinkers from this chamber or second furnace can be raked out
from time to time, as may be required, through the opening or space beneath the
arch d, d, in the ash pit.
Having now described the nature and object of my said Invention, together with
the manner in which the same is to be or may be performed or carried into practical
effect, I wish it to be understood that I claim as my Invention, dispensing with the
ordinary "bridge" of the furnace and supporting the rear ends of the fire-bars by
means of an arch formed as above described, a fire-brick or cast-iron slope being
fixed a short distance behind the same, substantially in the manner and for the
purposes herein-before more particularly set forth and described.
In witness whereof, I, the said Francis William Ashton, have hereunto set
my hand and seal, this Eighth day of October, in the year of our Lord One
thousand eight hundred and seventy-eight.
F. W. ASHTON, (L.S.)