IMPROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO FURNACES, AND FOR PREVENTING RADIATION OF HEAT FROM FIRE DOORS AND OTHER PARTS OF THE FRONTS OF FURNACES
Year: 1853

page_text: LETTERS PATENT to Thomas Symes Prideaux, of St. John's Wood, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN APPARATUS
FOR REGULATING THE SUPPLY OF AIR TO FURNACES, AND FOR PREVENTING
RADIATION OF HEAT FROM FIRE DOORS AND OTHER PARTS OF THE FRONTS OF
FURNACES."
Scaled the 27th June 1854, and dated the 27th December 1853.
PROVISIONAL SPECIFICATION left by the said Thomas Symes Prideaux
at the Office of the Commissioners of Patents, with his Petition, on the
27th December 1853.
THOMAS SYMES PRIDEAUX, of St. John's Wood, in the County of
Middlesex, do hereby declare the nature of my said Invention for "IMPROVE-
MENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO FURNACES, AND FOR
PREVENTING RADIATION OF HEAT FROM FIRE DOORS AND OTHER PARTS OF THE
FRONTS OF FURNACES," to be as follows:-
This Invention has for its object the application of apparatus to the fire
doors of the furnaces of marine and other steam boilers and any desirable part
of other furnaces, with a view of regulating the admission of air to such

page_text: furnaces, in order to improve the combustion of the fuel and at the same time
preventing the radiation of licat outwards.
For this purpose the fire doors or other selected portion of the furnace are
made with moveable valves or shutters, which are to be opened immediately
after supplying fuel to the fire, and shut by degrees within a determined period
after firing, by means of water or other fluid being caused to pass through a
small opening, and yet managed to allow the piston or other instrument to be
moved freely when pressed in the opposite direction. The interior of the door
(or other portion of the furnace selected for the application of the valve) has
fixed to it a series of parallel inclined plates inclining in one direction, and a
second series of inclined parallel plates inclining in the other direction, (so as
to prevent the direct radiation of heat from the fire outwards,) and then a third
series of plates, which need not incline, with air spaces between each series.
The interior series of plates become very hot when the valves or shutters are
closed, but little of the heat reaches the exterior. On closing the fire door,
after supplying fuel to the fire, the shutters or valves are opened, and the air
passes freely between the highly heated plates, by which the air entering the
front of the furnace will be highly heated, and will contribute to the igniting
of the smoke, which would otherwise pass off from the furnace.
And the front of the furnace and ash-pit may be advantageously provided
with a similar heat isolating apparatus, vidclicit, series of parallel inclined
plates, those of the ash-pit being made moveable, so as to admit of the
apertures being closed at pleasure.
The fluid regulator will gradually close the shutters of the valve for sup-
plying air above the surface of tlic fuel as the green fuel becomes more and
more highly heated, and thus will be prevented the passage in of air in that
direction when the fuel has become well ignited, and a less quantity of air is
required
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Symes Prideaux in the Great Seal Patent Oflice on 30
the 27th June 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
SYMES PRIDEAUX, of Saint John's Wood, in the County of Middlesex, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 35
Patent, bearing date the Twenty-seventh day of December, in the year of our

page_text: Lord One thousand eight hundred and fifty-three, in the seventeenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Thomas Symes Prideaux, Her special license that I, the said Thomas
Symes Prideaux, my executors, administrators, and assigns, or such others as
I, the said Thomas Symes Prideaux, 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 "In-
PROVEMENTS IN APPARATUS FOR REGULATING THE SUPPLY OF AIR TO FURNACES, AND
FOR PREVENTING RADIATION OF HEAT FROM FIRE DOORS AND OTHER PARTS OF THE
FRONTS OF FURNACES," upon the condition (amongst others) that I, the said
Thomas Symes Prideaux, by an instrument in writing under my hand and
scal, should particularly describe and ascertain the nature of the said Inven-
tion, 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 Patont.
NOW KNOW YE, that I, the said Thomas Symes Prideaux, 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 statement thereof (that is to say) :-
This Invention has for its object the application of apparatus to the fire
doors of the furnaces of marine and other steam boilers and any other
desirable part of other furnaces, with a view of regulating the admission of air
to such furnaces, in order to improve the combustion of the fuel and at the
same time preventing the radiation of licat outwards. For this purpose the fire
doors or other selected portion of the furnace are made with moveable valves
or shutters, which are to be opened immediately after supplying fuel to the fire,
and shut by degrees within a determined period after firing, by means of water
or other fluid being caused to pass through a small opening, and yet arranged
to allow the piston or other instrument to be moved freely when pressed in the
opposite direction. The interior of the door (or other portion of the furnace
selected for the application of the valve) has fixed to it a series of parallel
inclined plates inclining in one direction, and a second series of inclined parallel
plates inclining in the other direction, (so as to prevent the direct radiation of
heat from the fire outwards,) and then a third serics of plates, which need not
incline, with air spaces between each series. The interior series of plates
become very hot when the valves or shutters are closed, but little of the heat
reaches the exterior. In closing the fire door, after supplying fuel to the fire,

page_text: the shutters or valves are opened, and the air passes freely between the highly
heated plates, by which the air entering the front of the furnace will be highly
heated, and will contribute to the igniting of the smoke, which would other-
wise pass off from the furnace. And the front of the furnace and ash-pit may
be advantageously provided with a similar heat isolating apparatus, viz', series
of parallel inclined plates, those of the ash-pit being made moveable, so as to
admit of the apertures being closed at pleasure. The fluid regulator will
gradually close the shutters of the valve for supplying air above the surface of
the fuel as the green fuel becomes more and more highly heated, and thus will
be prevented the passage in of air in that direction when the fuel has become
well ignited, and a less quantity of air is required.
Having thus stated the nature of the Invention I will proceed to describe
the manner of performing the same.
Figure 1 shows a section of an apparatus applied to the door of a furnace
constructed according to my Invention; Figure 2 is a front view of the same;
Figure 3 shows a side view; Figure 4 is a plan; Figure 5 shows a horizontal
section; and Figure 6 shows a section of the apparatus which I prefer to use
for regulating the line at which the supply of air should be shut off. In each
of these Figures the same letters of reference indicate the same parts. The
apparatus is arranged suitable for being introduced through an opening in the
door of a furnace, and of being affixed thereto by screws or otherwise; hence,
when the door is opened or closed, the apparatus will be moved with the door,
and, in fact, form part of it. a, a, is the case of the apparatus, in the front of
which are a series of plates b, b, which move on axes c, c; at either end, for cach
of these plates, is fixed an arm d, which at its other end is attached by a pin
joint to the bar e. Motion is given to the bar e by means of a rod or or link f,
which is attached at its lower end by a pin joint to the bar e, and at its upper
end by a pin joint to the lever g, which by its own weight and the weight of
the parts above described, which are connected to it, would at all times be down,
and the several plates b, b, would be shut or closed, and thus prevent the
ingress of air; and this is to be prevented, and the time of the closing of the
plates is to be regulated, so that they may be open immediately after supplying
coal to the fire, and then gradually close. This regulation I prefer to be
accomplished by means of a cylinder and piston and i. The piston has a
cupped valve of vulcanized india-rubber, which prevents the water contained
in the cylinder from passing up from below the piston in that direction, and

page_text: the water can only pass from the space below the piston to the space above the
piston by the passage j, j, and the extent or size of such passage at its lower
end is adjusted by the screw k, by which the time of the descent of the piston i
can be regulated with the greatest nicety. The piston rod of the piston i is
connected to the lever 7 by a link, as shown, and by reason of the flexible cup
of the piston the piston can be readily raised by means of the lever g, as the
water will pass readily when the piston i is raised. At the back of the
plates b, b, are a series of fixed inclined plates 1, 2, inclining in one direction.
m, m, is a series of inclined plates, inclining in an opposite direction, 12 being
an air space between them. o, o, is another scrics of plates, and P another air
space. Supposing the fire door to have been closed some time the inner series
of parallel plates at o, o, nearest the fire will have become very hot. On a
fresh supply of coals being required to the fire the furnace door will be opened
and the fuel thrown in; the door will then be closed, and the stoker is to raise
the lever g, which will open the plates b, so that air will rush in through the
apparatus and become highly heated, and in that state will flow over the fire
and combine with the products evolved from the fresh fuel, by which such pro-
ducts will become ignited and burned, thus preventing the evolution of smoke
from the chimney; and as the coal becomes more ignited the incoming air will
be more and more diminished by reason of the shutting or closing of the plates
or valves b, and by the time that no dense products or smoke are being evolved
from the fuel the coming in of air at the apparatus will be stopped, and the
apparatus will again become more and more heated till more fuel is required
to be fed into the fire. In addition to applying such apparatus to the furnace
door, the licat isolating portion of the apparatus may be applied in a like
manner to the ash-pit door, but so arranged as to be fixed at pleasure at any
desired position to insure sufficient space for the admission of air for the time
being to the ash-pit, to support combustion. Figure 7 shows so much of a
reverberatory or other furnace where the feeding of the fuel on to the fire-bars
takes place at one part of the furnace, and the apparatus for regulating the
supply of air to the fresh fuel is applied at another part of the furnace. x is
the opening for supplying the fresh fuel on to the fire-bars. y is a partition of
fire-brick or fire-clay, with passages for the air at y', in front of which the door
and apparatus for regulating and shutting off the supply of air above the fire-
bars is placed. I prefer to have a door in such cases, but it is not absolutely
necessary to do so. This apparatus, like that above described, is opened
and brought into action after charging with fresh fuel, and the apparatus will
then go on closing itself, as before explained.
Having thus described the nature of my Invention, and the manner of per-

page_text: forming the same, I would have it understood that I make no claim to the
mechanical parts separately, nor do I confine myself to the details. But what
I claim is, the combined apparatus herein described, applied to the door or
other part of a furnaco.
In witness whereof, I, the said Thomas Symes Prideaux, have hereunto
hand and seal, this Twenty-seventh day of June, in the year
of our Lord One thousand cight hundred and fifty-four.
set my
Witness,
S. CARPMAEL.
THOMAS SYMES PRIDEAUX. (L.S.)