IMPROVEMENTS IN FURNACES AND FIRE-PLACES, AND IN THE PREVENTION OF SMOKE
Year: 1853

page_text: LETTERS PATENT to John Ferguson, of Heathfield, in the County
of Lanark, North Britain, Brick and Pottery Manufacturer, for
the Invention of "IMPROVEMENTS IN FURNACES AND FIRE-PLACES,
AND IN THE PREVENTION OF SMOKE."
PROVISIONAL SPECIFICATION left by the said John Ferguson at
the Office of the Commissioners of Patents, with his Petition, on
the 16th November 1853.
1, JOHN FERGUSON, of Heathfield, in the County of Lanark, North
Britain, Brick and Pottery Manufacturer, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN FURNACES AND FIRE-PLACES,
AND IN THE PREVENTION OF SMOKE," to be as follows:-
This Invention relates to the so arranging the flues and furnace
details of steam boiler and other furnaces that considerable economy
in fuel may be secured, whilst the usual discharge of smoke is avoided.
As adapted for an ordinary cylindrical boiler furnace with an external
fire, a cold air supply pipe is led into the furnace seat or mounting on
each side of the fire door at the front end. This pipe or flue runs

page_text: horizontally into the seating, and passes in each case by a slight
bend into a narrow horizontal flue formed in the seating, just beneath
the level of the flame bed, beneath the boiler and behind the bridge.
This flue runs along beneath the flame bed, and is only separated
therefrom by a slight thin cover to the further end of the boiler; here
it takes a bend outwards, and returns back to the front end in a line
parallel to the first run of the flue, and at the same level. In this way
the cold air takes up considerable heat from the flame bed, and in this
heated state it is passed amongst the gases as they pass from the grate.
For this purpose the extreme front end of the flue passes by a short
bend or angle towards the line of the boiler's centre, and here enters
the outer end of a hollow or cellular bridge standing up from the
base of the seating at the back end of the grate bars. Precisely the
same arrangement is followed out on each side of the boiler, and the
hollow bridge has a central division across it to prevent the mingling of
the two currents. At the back of the hollow bridge are a set of
openings or jet passages, so that the heated air supplied to the bridge
chamber can thus escape in a diffused state on the side furthest from
the grate bars; here the air jets mingle with the gases, passing over the
front hollow fixed bridge, and the whole current of mixed heated air
and gases then passes onwards and strikes against the front of a vertical
hanging bridge of considerable depth. This bridge stops the progress
of the current, and enables the component matters thereof to become
fully mixed. In this state the combined current descends and passes
beneath the bottom edge of the hanging bridge, and rises up at the
other side and over the top of a third bridge or flame spreader into
the flame bed. Thus there are, as it were, two mixing chambers for
the air and gases, and the whole become well commingled, whilst an
economical use is made of the flame bed heat in passing the cold air
along the bottom flues. Although this arrangement has been specially
mentioned in its application to a certain kind of steam boiler, yet it is
equally applicable to all other varieties of furnace or fire place, whether
for steam purposes or not.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Ferguson in the Great Seal Patent Office
on the 16th May 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I
JOHN FERGUSON, of Heathfield, in the County of Lanark, North
Britain, Brick and Pottery Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of November, in the
year of our Lord One thousand eight hundred and fifty-three, in the
seventeenth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Ferguson, Her special
license that I, the said John Ferguson, my executors, administrators,
and assigns, or such others as I, the said John Ferguson, my executors,
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 FUR-
NACES AND FIRE-PLACES, AND IN THE PREVENTION OF SMOKE,"
upon the
condition (amongst others) that I, the said John Ferguson, 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 calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Ferguson, do hereby
declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon, that
is to say:
My said Invention relates to the so arranging the flues and furnace
details of steam boiler and other furnaces that considerable economy
in fuel may be secured, whilst the usual discharge of smoke and uncon-

page_text: sumed gases is avoided. As adapted for an ordinary cylindrical boiler
furnace with an external fire, a cold air supply pipe is let into the fur-
nace seat or mounting on each side of the fire door at the front end.
This pipe or fue runs horizontally into the seating, and passes in each
case by a slight bend into a narrow horizontal flue formed in the
seating just beneath the level of the flame bed, beneath the boiler and
behind the bridge. This flue runs along beneath the flame bed, only
separated therefrom by a slight thin cover to the further end of the
boiler; here it takes a bend outwards, and returns back to the front
end in a line parallel to the first run of the flue, and at the same level.
In this way the cold air takes up considerable heat from the flame bed,
and in this heated state it is passed amongst the gases as they proceed
from the grate. For this purpose the extreme front end of the flue
passes by a short bend or angle towards the line of the boiler's centre,
and here enters the outer end of a hollow or cellular bridge standing
up from the base of the seating at the back end of the grate bars.
Precisely the same arrangement is followed out on each side of the
boiler, and the hollow bridge has a central division across it to prevent
the mingling of the two currents. At the back of the hollow bridge
are a set of openings or jet passages, so that the heated air supplied to
the bridge chamber can thus escape in a diffused state on the side
furthest from the grate bars. Here the air jets mingle with the gases
passing over the front hollow fixed bridge, and the whole current of
mixed heated air and gases then passes onwards and strikes against the
front of a vertical hanging bridge of considerable depth. This bridge
stops the progress of the current, and enables the component matters
thereof to become fully mixed. In this state the combined current
descends and passes beneath the bottom edge of the hanging bridge, and
rises up at the other side and over the top of a third bridge or flame
spreader into the flame bed. Thus there are, as it were, two mixing
chambers for the air and gases, and the whole become well commingled,
whilst an economical use is made of the flame bed heat in passing the
cold air along the bottom flues. Although this arrangement has been
specially mentioned in its application to a certain kind of steam boiler
and fittings, yet it is equally applicable to all or most other varieties of

page_text: furnace or fire place, whether for steam purposes or not; and in order
that my said Invention may be properly understood, I shall now pro-
ceed to describe the several Figures on the Sheet of Drawings hereunto
attached. Figure 1, on the Sheet of Drawings is a front end elevation
of a steam boiler and furnace arranged according to one modification of
my Invention; Figure 2, is a vertical longitudinal section of the same
taken through the centre of the boiler; Figure 3, is a vertical trans-
verse section, one half taken through the air space immediately in front
of the apertures by which the air enters the main flue, and the other
half taken a little behind this, where the entering branches of the air
passage bend in towards the centre line of the furnace; Figure 4, is a
horizontal longitudinal section of the furnace, one half being taken at
two different levels through one of the air passages, and the other at a
higher level, so as to exhibit the route of the main flue. The boiler A,
which I have selected for representation in combination with my im-
proved furnace, is of the ordinary cylindrical form, having hemispherical
ends. It is embedded in a rectangular structure or seat of brickwork B,
in which are formed the furnace, flue, and air passages. The grate C, is
at one end of the boiler, and the main flue D, issuing from it at the back,
first passes over the bridge E, and then under the hanging bridge F;
after this it runs along under the boiler until it reaches its its back end,
where it takes a turn upwards to the left hand side, as at G, and returns
along this side of the boiler to the front at II it next runs back along
off to the chimney at I.
the right side of the boiler, and finally passes
The entrances to the air passages, of which there is one on each side of
the furnace, are at J, a little below the level of the fire bars. Theso
entrances are provided with throttle valves or adjustable passages K,
for adjusting the indraught of air, the spindles of the valves passing
through the brick work into the ashpit, where they have lever handles
I, fixed upon them, by means of which they can be set in any required
position. These air passages pass horizontally and parallel with the
boiler's axis, to a short distance behind the hanging bridge F, they then
turn inwards as at M, and continue their course towards the back end
of the boiler, as at N, immediately below the main flue D, being sepa-
rated from this last by a very thin partition O. On reaching the back

page_text: of the boiler the air passages diverge to the right and to the left, as at
P, at the same time rising to a higher level; they thence return to the
front end of the boiler as at Q, being also here separated from portions
of the main flue by thin partitions R; they finally descend as at S, to
a space T, formed inside the bridge E, and this space T communicates
with the main flue D, by apertures U, in the back of the bridge E. In
this manner, the air entering at J, in traversing the range of passages
just described, takes up the heat radiated from the main flue through the
thin partitions O and R, thereby utilising this heat, which would other
wise be more or less wasted, whilst at the same time the air thus heated
acts more efficiently on commingling with the gases proceeding from
the furnace, so that the fuel is more thoroughly and perfectly consumed,
none passing off in the form of smoke. According to another modifica-
tion of my said Invention, the air entering by openings at any suitable
or convenient point or points, is first made to traverse passages on the
side of or below such portions of the main flue as are furthest from the
fire, and is afterwards made to pass through passages immediately
below or on the sides of that portion of the main flue which is nearest
to the fire, and is consequently the hottest, the air being thence admitted
into the main fiue so as to mingle with the gases therein, in a similar
manner to that described in reference to the modification which I have
first explained. In all cases the air passages are divided off from the
portions of the main flue by very thin partitions, so that the air may
take up the radiated heat as easily as possible. It is to be understood
that by the general system of introducing air, as I have herein-before
described, the air so admitted is heated to such an extent as to prevent
all danger of cooling the furnace or lowering the steam pressure in the
boiler. By the herein-before described plan I effect the complete
combustion of the smoke and the combustible gascous products, whilst
I at the same time secure great economy in the consumption of fuel
as compared with existing systems; with my arrangements I also effect
a great saving in attendance, as when once properly set the proper
action of the furnace is kept steadily up without any further adjustment
of the valves or other details, except in cases of extraordinary variation
in the working routine.

page_text: 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 may observe, in conclusion, that I do not con-
fine or restrict myself to the precise details or arrangements which I
have had occasion to describe or refer to as many variations may
be made therefrom without deviating from the principles or main
features of my Invention; but 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,-
First, the general arrangement and construction of furnaces or fire-
places, as herein-before described.
Second, the system or mode of constructing furnaces or fire-places
wherein passages are formed for the introduction of air into the main
flue or flues, such passages being carried along close to the main flue
passages, from which they are separated by very thin partitions, so that
the air may take up the heat radiated from the main flues, as herein-
before described.
Third, the system or mode of arranging and constructing furnaces or
fire-places wherein a hanging or intermediate bridge is combined with
or inserted in a mixing or combination chamber, for the commingling
of the gaseous products of combustion and air.
Fourth, the system or mode of arranging and constructing furnaces
or fire-places wherein the gascous draught current takes a descending
and ascending or tortuous route through a mixing or combination
chamber.
Fifth, the application and use of brick or earthenware ducts or
passages for heating the air prior to entering the furnace or flue.
In witness whereof, I, the said John Ferguson, have hereunto
set my hand and seal, this Twelfth day of May, in the year
of our Lord One thousand eight hundred and fifty-four.
JOHN FERGUSON. (L.S.)