IMPROVEMENTS IN FURNACES
Year: 1854

page_text: LETTERS PATENT to Thomas Forsyth, of Wolverton, in the County of
Buckingham, Engineer, for the Invention of "IMPROVEMENTS IN FURNACES."
Sealed the 25th July 1854, and dated the 24th February 1854.
PROVISIONAL SPECIFICATION left by the said Thomas Forsyth at the
Office of the Commissioners of Patents, with his Petition, on the 24th
February 1854.
I, THOMAS FORSYTH, of Wolverton, in the County of Buckingham, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
FURNACES" to be as follows:-
This Invention has for its object to construct furnaces in such manner that
the air supplied thereto shall be commensurate for supporting combustion of
the fuel for the time being in the furnaces, and also for igniting products
evolved from the fuel. For this purpose I arrange the fire bars of a furnace
in such manner that they shall act in some respect as part of a weighing
machine, that is, that they shall descend by the weight of fuel for the time
being on them, and, according to the extent of their movement, they regulate
and govern the quantity of air admitted below the fire bars, and also at the
bridge or other parts of the furnace. Hence it will be understood that the

page_text: fire bars will be caused to descend by the additional weight of a fresh charge
of fuel, and consequently a larger supply of air will be allowed to pass at that
moment, and the quantity of air admitted will decrease as the weight of fuel
on the fire bar becomes lighter, and this is consequent on the movement of
the bars and the balance weight or apparatus in connection with the fire bars,
communicating with and giving motion to the slides or valves by which the
admission of air is regulated.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Forsyth in the Great Seal Patent Office on the 3rd
August 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FORSYTH, of Wolverton, in the County of Buckingham, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of February, in the year of our
Lord One thousand eight hundred and fifty-four, in the seventeenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Forsyth, Her special licence that I, the said Thomas Forsyth,
my executors, administrators, and assigns, or such others as I, the said Thomas
Forsyth, my executors, administrators, and 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 FURNACES,'
upon the condition (amongst others) that I, the said Thomas Forsyth, 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 Thomas Forsyth, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment thereof (that is to say):-

page_text: This Invention has for its object to construct furnaces in such manner that
the air supplied thereto shall be commensurate for supporting combustion of
the fuel for the time being in the furnaces, and also for igniting products
evolved from the fuel. For this purpose I arrange the fire bars of a furnace in
such manner that they shall act in some respect as part of a weighing machine,
that is, that they shall descend by the weight of fuel for the time being on
them, and, according to the extent of their movement, they regulate and govern
the quantity of air admitted below the fire bars, and also at the bridge or other
parts of the furnace. Hence it will be understood that the fire bars will be
caused to descend by the additional weight of a fresh charge of fuel, and con-
sequently a larger supply of air will be allowed to pass at that moment, and
the quantity of air admitted will decrease as the weight of fuel on the fire bars
becomes lighter, and this is consequent on the movement of the bars and the
balance weights or apparatus in connection with the fire bars, communicating
with and giving motion to the slides or valves by which the admission of air
is regulated.
Having thus stated the nature of my said Invention, I will proceed to
describe the manner of performing the same.
DESCRIPTION OF THE DRAWING.
Figure 1 is an external elevation of a boiler furnace, having my Invention
applied thereto; Figure 2 is a transverse section thereof.
Figure 3 is a plan of the boiler, shewing the manner in which I prefer to
economise heat, by having heated water supplied to a boiler, by causing it to
be pumped into a hollow cylindrical compartment, through which the vertical
tubular flues from the fire-place pass, hence there is a feed pipe or vessel of
large diameter constantly full of hot water, which at its lower end is in com-
munication with the boiler. The arrangement shewn is for taking the hot
water from a series of tanks, which receive the water from .the twyers of
smiths forges. But my Invention is independent of such means of supply of
hot water to the boiler, and may be used without any such additions. a, a, is
an oval boiler, but other forms of boilers may be used; are the vertical
tubular flues, surrounded by the water vessel c, into which water is pumped
by the pump & from the cisterns e, which receive a supply of water from the
cistern f, which, having passed through the twyers 7 of the smiths forges,
flows by the pipes h into the cisterns; i is a hand valve to be screwed down
when the pressure becomes less in the boiler than in the column of water in
the vessel surrounding the vertical flues.

page_text: Figure 4 shews a plan and section of a fusible plug, and the manner of
fixing it in the boiler, by the aid of a brass screw socket as shewn, the
object being to raise the plug, so that it will fuse before the water is so
The fire bars, according
far reduced as to cause injury to the boiler.
to my Invention, are made part of a weighing machine, and are thus
the means of regulating the quantity of air supplied to the fuel on the
fire bars, the quantity of air supplied being decreased as a quantity of
fuel on the bars decreases; hence when a fresh supply of coal has been
put on to the fire bars, the products going off therefrom will require the
largest supply, and this will take place in consequence of the greater weight
on the fire bars; but as the fresh fuel consumes, and less and less products go
off, there will be a decreasing requirement for 'air, and the movement of the
fire bars will be the cause of closing the openings by degrees where the
supply of air takes place; and I would state, that although a particular
arrangement of parts is shewn for accomplishing this end, I do not confine
myself thereto, as it will be evident to a mechanic that the fire bars may be
arranged to work as part of a weighing machine, differently formed to what is
shown in the Drawing, and yet in substance be the same in action as that
shewn. j,j, are the fire bars, and having on either side bricks to prevent the
fuel touching the sides of the outer fire place, which might impede the free
action of the weighing machine. The inner fire place is carried by the plat-
form frame or plate j, j'; and the platform j, j, is supported by four rods
,, each having a spring weighing machine 7", which is what I prefer to
employ as the means for counterbalancing the fire place and the fuel. The
spring weighing machines are provided with screw nuts j, for regulating the
position of the fire bars. On either side of the fire there are air passages k,
with a cover l, which by a connecting rod m is attached to the platform j', and
is moved thereby, by which means, when a fresh charge of coals have been
put on to the fire bars, they will descend, and open the air passages to a greater
or lesser extent, according to the quantity of coals thrown on, and air will
pass through the uncovered openings; and as the fuel becomes consumed the
air passages will be gradually closed, and less and less air will pass.
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that I make no claim to any
of the mechanical parts separately, nor do I confine myself thereto, so long as
the peculiar character of my Invention be retained; but what I claim is,—
The combining of the fire bars of a furnace with apparatus in such manner
as to cause the fire bars to become part of a weighing machine, and so act as

page_text: to regulate the supply of air to the fuel thereon, and so that the supply of
air shall be caused to be shut off as the weight of fuel on the fire bars
decreases.
In witness whereof, I, the said Thomas Forsyth, have hereunto set my
hand and seal, this Thirty-first day of July, in the year of our Lord
One thousand eight hundred and fifty-four.
THOMAS FORSYTH. (L.S.)
Witness,
WILLIAM ROWLAND,
July 31st, 1854.
Wolverton.