IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES OR FIRE-PLACES
Year: 1860

page_text: LETTERS PATENT to James Robertson, of No. 3, Stanisby Road, East
India Road, in the County of Middlesex, Cooper, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES OR FIRE-PLACES."
Sealed the 27th September 1860, and dated the 3rd April 1860.
PROVISIONAL SPECIFICATION left by the said James Robertson, at the
Office of the Commissioners of Patents, with his Petition, on the
3rd April 1860.
I, JAMES ROBERTSON, of 3, Stanisby Road, East India Road, in the County
of Middlesex, Cooper, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES OR FIRE-PLACES," to be
as follows:-
This Invention relates to a peculiar construction and arrangement of steam
:boiler, and other furnaces or fire-places, whereby economy of fuel and pre-
vention of smoke is effected.
According to this Invention it is proposed to adapt to any ordinary or other
furnace a moveable ash-pit bottom, which is hinged in the ash-pit at the end
farthest from the fire door, and is supported at its front end by counterbalance
weights and chains, or other suitable contrivance, which will admit of the
bottom being lowered or raised at its front end, so as to decrease or increase
as required the draught under the fire bars.

page_text: By another arrangement, this moveable bottom may be hinged at the front
end, and its back end lowered or raised for the same purpose, an aperture
being made in the bottom at or near its back end to allow of the admission of
air beneath the fire bars, which air after traversingalong the under side of the
fire bars to the front end or mouth of the furnace may be admitted at that
part on to the upper surface of the grate, and pass over the fuel on its way to
the chimney or uptake.
Another part of my Invention consists in the application and use of rotatory
fire bars, each separate bar being made to rotate on its axis by the aid of
suitable gearing connecting the series. By this/arrangement the formation of
clinkers is prevented, as the surfaces of the bars may be changed as often as
is required by rotating them either by hand or otherwise. These fire bars
should be of a round, oval, polygonal, or other section, which will admit of
their rotating in concert.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Robertson in the Great Seal Patent Office on the
3rd October 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ROBERTSON, of No. 3, Stainsby Road, East India Road, in the County of
Middlesex, Cooper, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of April, in the year of our Lord One
thousand eight hundred and sixty, in the twenty-third year of Her reign,
did for Herself, Her heirs and successors, give and grant unto me, the
said James Robertson, Her special license that I, the said James Robertson,
my executors, administrators, and assigns, or such others as I, the said James
Robertson, myexecutors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE CONSTRUCTION OF FURNACES OR FIRE-PLACES," upon the condition (amongst
others) that I, the said James Robertson, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six

page_text: calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said James Robertson do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
My said Invention relates to a peculiar construction and arrangement of
steam boiler, and other furnaces or fire-places, whereby economy of fuel, and
prevention of smoke is effected.
According to this Invention it is proposed to adapt to any ordinary or other
furnace, a fixed or moveable plate or ash-pit bottom, which when moveable is
hinged in the ash-pit at the end farthest from the fire door, and is supported
at its front end by counterbalance weights and chains, or other suitable
contrivance, which will admit of the bottom being lowered or raised at its front
end, so as to decrease or increase as required the draught under the fire
bars.
By another arrangement this moveable bottom may be so placed as to
leave an open space for the admission of air round its back end from the ash
pit,suchair then passing between the under side of the fire bars and the plate,
to the front end or mouth of the furnace, at which part it is admitted on to
the upper surface of the grate, and passes over the fuel on its way to the
chimney or uptake.
Another part or my Invention consists in the application and use of rotatory
fire bars, each separate bar being made to rotate on its axis by the aid of
suitable gearing connecting the series. By this arrangement the formation of
clinkers and their adhesion to the bars is in a great measure prevented, as the
surfaces of the bars may be changed as often as is required by occasionally
rotating them either by hand or otherwise. These fire bars may be of a
round, oval, polygonal, or other section, which will admit of their rotating in
concert, and may be grooved spirally or made in the form of screws for the
purpose of urging forward the clinkers and cinders towards the mouth of
the furnace, and hence they are easily removed.
And in order that the said Iuvention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
Figures.
Figure 1 of the annexed Sheet of Drawings represents a longitudinal

page_text: vertical section of one arrangement of my improved furnace as applied to an
ordinary internal flue steam boiler; and Figure 2 is a partial end elevation of
the same, and partial transverse section taken through the fire bars.
A, A, is the body or shell of the boiler, and B, B, the internal flue, in which
my improved furnace is constructed; C, C, are the fire bars, and D, the ash-
pit. These bars are supported at their extremities in suitable bearers E, E,
and may be made of any shape which will admit of their revolving each on its
own longitudinal axis. In my Drawing I have represented them as being
made of a circular section. These bars may be either plain or may have a
number of slots or perforations a, a, made transversely in them, so as to admit
of a free passage of air through them into or amongst the fuel, and may be
provided with a spiral groove on their surfaces, as shewn at b,'b, so that when
the bars are rotated the grooves will tend to draw forward the cinders and any
clinkers which may be formed towards the mouth of the furnace, to be there
discharged. Various mechanical contrivances may be used for imparting a
rotatory or circular vibratory motion to the entire series of bars, but I prefer
to employ the arrangement shewn in theDrawings, which consists in securing
a spur pinion F on to the end of each bar,such pinions gearing together so as
to form a train of gearing which, on receiving motion by means of a winch
handle G, will transmit such motion to the entire series of bars. In order to
protect the teeth of these wheels from clogging by the dropping therein of
pieces of coal or ciuders, I propose to cover them over by the dead plate H.
By occasionally turning the fire bars in the manner above described they
will last much longer than the ordinary fixed ones, as all parts will be
equally subjected to the action of the incandescent fuel, whilst at the same
time the formation of clinkers upon them will be entirely or in a great
measure prevented. Immediately below the fire bars, and in close proximity
thereto, I place a plate I, which is hinged at its back end c to the side of the
ash-pit, whilst its front end is free to be raised or lo wered nearer to or further
from the bars, according as more or less draught is required, a counterweight
and chaindattached to its front edge serving to facilitate this adjustment. An
opening or space K is left between the back ends of the fire bars and the
bridge L, and over this opening is placed a grating M. When a charge of
fresh fuel is introduced into the furnace the front end of the plate I is elevated
so as to bring it within a few inches of the fire bars, and the air which enters
below the grate must consequently pass between the surface of this plate and
the under sides of the fire bars. As this plate becomes considerably heated by
its close proximity to the incandescent fuel on the grate, and as it receives the
hot cinders and unconsumed fuel which drops from the grate, it follows that

page_text: the air as it passes along between the bars and the plate will become heated,
and will receive an additional degree of heat by passing through the highly
heated grating M, which also subdivides it into a number of streams or jets,
in which form it mingles with the carbon and unconsumed gases as they pass
over the bridge, and effectually prevents the formation of smoke. As the
combustion of the fresh fuel proceeds the plate I may be gradually lowered so
as to reduce the draught, thereby regulating the supply of air according to the
requirements of combustion.
In Figures 1 and 2 I have shown the plate I in its lowest position, in
which state the cinders and ashes may be readily removed from it with the
front of the ash-pit. In order to adapt this plate to the semi-circular form of
the ash-pit, and so allow of its descending to the required extent, I propose to
attach hinged flaps i, i, to the sides of the flap, which flaps will gradually
fold up as the plate descends, as shewn clearly in Figure 2. By the applica-
tion of the plate I below the fire bars the great loss and radiation of heat from
the ash-pit into the stokehole, which is found so objectionable in steam boats,
is prevented, as this heat is carried inwards to the flues by the draught beneath
the fire bars.
Figure 3 represents a longitudinal section of a slightlymodified arrangement
of furnace, and Figure 4 is a sectional plan of the same, taken partly above the
fire bars and partly below them. In this modification the rotating fire bars
C,C,which areof a similar construction and arrangement to those herein-before
described, extend up to the fire bridge, whilst the hinged plate Idoes not extend
so far, thereby leaving an opening or passage K between the back or hinged
end of the plate I and the fire bridge. The front end of the plate I is arranged
so as to be capable of being elevated or depressed, as described in reference to
Figures 1 and 2, for the purpose of removing the ashes therefrom. The front
ends of the fire bars are made of rather smaller diameter, as shown in
Figure 4, for the purpose of affording a free passage for the air between them
at that part. The air enters the mouth of the ash-pit, passes through the
opening or space K, and thence along the heated surface of the plate I
between it and the under side of the fire bars, when it becomes considerably
heated, and in that state passes between the fire bars at their front ends, and
over the entire surface of the fuel on its way to the flue. Although the greater
portion of the hot air passes in the one case through the opening K and
grating M, and. in the other through the widened spaces between the front
ends of the fire bars, yet a certain portion of it will also pass into the fuel
dispersed over the grate through the perforations in the fire bars and through
the spaces between such bars, as shown by the arrows. In some cases the

page_text: plate I may be fixed in place of moving on a hinge, and it should then be
-fitted in a horizontal or nearly horizontal position at sucha distance below the
fire bars as to afford facility for removing the cinders deposited thereon.
When a fixed plate is used any suitable contrivance may be employed for
regulating the draught of air.
Although I have only illustrated my Invention as applied to a stationary
cylindrical boiler furnace, it is obvious that the same improvements may
be applied to other existing furnaces without materially interfering with their
construction.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,―
1st, the general constructions and arrangements of furnaces or fire-places
for effecting good combustion, and preventing the formation of smoke, as
herein-before described.
2nd, the application and use to and in furnaces or fire-places of a fixed
or adjustable plate placed immediately beneath the fire bars, for the purposes
herein-before described.
3rd, the application and use to and in furnaces or fire-places of rotating
fire-bars, for the purposes herein-before described.
4th, the combination of a fixed or adjustable plate with rotatory fire bars,
as herein-before described.
In witness whereof, I, the said James Robertson, have hereunto set
my hand and seal, this Second day of October, One thousand eight
hundred and sixty.
JAMES ROBERTSON. (L.S.)