IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR EFFECTING THE MORE PERFECT COMBUSTION OF THE FUEL
Year: 1862

page_text: LETTERS PATENT. to Samuel Hazard Huntly, of No. 50, Upper Baker
Street, Regent's Park, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR EFFECTING THE MORE
PERFECT COMBUSTION OF THE FUEL."
Sealed the 12th December 1862, and dated the 17th June 1862.
PROVISIONAL SPECIFICATION left by the said Samuel Hazard Huntly
at the Office of the Commissioners of Patents, with his Petition, on the
17th June 1862.
I, SAMUEL HAZARD HUNTLY, of No. 50, Upper Baker Street, Regent's
Park, in the County of Middlesex, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR EFFECTING
THE MORE PERFECT COMBUSTION OF THE FUEL," to be as follows:-
My Invention consists in constructing inside the fire-box or in the space
over the fire-grate of furnaces, air flues, or passages formed in fire-clay or any
other suitable material, and provided with perforations, holes, or slits through
which atmospheric air is caused to pass, and to impinge in small jets on to the
top of the fire, by which a more perfect combustion of the fuel is effected.
This is of particular advantage when the fuel has been freshly fed on, and the
passage of the air through the fire-bars is more obstructed than when the fire

page_text: is clear, as the heat previously imparted to the mass of fire-brick or other
suitable material in which the air flues are formed is in that case radiated on
to the top of the fresh fuel, and distils the gases from the same, whilst the air
passing through the apertures or perforations in these flues effects the perfect
combustion of these gases. I prefer to arrange the said air flues or passages
in such a manner that the air passes into them from the ash-pit or space below
the fire-bars; whereby the quantity of air that impinges on to the top of the
fire will increase in proportion as the quantity that passes through the fire-bars
diminishes, and vice versa, and thus the apparatus is rendered self-regulating
without any additional mechanism being requisite for this purpose. In some
cases, however, I do not make the air flues or passages communicate with the
ash-pit, but conduct the air into them in any other convenient manner, and in
some cases I provide dampers or valves to these air flues to regulate at
pleasure the quantity of air that impinges on to the top of the fire. The form,
number, and arrangements of these air flues or passages, as also of the
apertures through which the air passes: from them on to the fire, may be
variously modified according to the requirement of the fuel employed, and
nature of the furnace to which they are applied. Thus in one arrangement
I mould them in blocks of fire-clay, which form more or less a complete
lining to the fire-box, and in some cases I extend such air flues beyond the
fire-box or space immediately over the fire-grate, so as to act upon any com-
bustible gases that may have passed away from the fire unconverted.
other cases I line the fire-box or space above the fire-grate only partially with
such air flues, and in some cases I cause the flame and products of combustion
to pass both underneath and over the top of such air flues, in which case they
may be pierced on top and bottom, if found convenient, and be supplied with
air from the front, or sides, or from the ash-pit at bottom.
In
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Samuel Hazard Huntly in the Great Seal Patent Office on
the 17th December 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, SAMUEL
HAZARD HUNTLY, of No. 50, Upper Baker Street, Regent's Park, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of June, in the year of our Lord

page_text: One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Samuel Hazard Huntly Her special licence that I, the said Samuel
Hazard Huntly, my executors, administrators, and assigns, or such others as
I, the said Samuel Hazard Huntly, 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 "IM-
PROVEMENTS IN THE CONSTRUCTION OF FURNACES FOR EFFECTING. THE MORE PERFECT
COMBUSTION OF THE FUEL," upon the condition (amongst others) that I, the said
Samuel Hazard Huntly, my exccutors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, 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 Samuel Hazard Huntly, do hereby declare
the nature of the 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 thereof, reference being had to the accompanying Drawing, and to
the figures and letters marked thereon, that is to say :-
My Invention consists in constructing inside the fire-box, or in. the space
over the fire-grate of furnaces, air flues, or passages formed in fire-clay or any
other suitable material, and provided with perforations, holes, or slits, through
which atmospheric air is caused to pass, and to impinge in small jets on to the
top of the fire, by which a more perfect combustion of the fuel is effected.
This is of particular advantage when fuel has been freshly fed on, and the
passage of the air through the fire-bars is more obstructed than when the fire
is clear, as the heat previously imparted to the mass of fire-brick or other
suitable material, in which the air flues are formed, is in that case radiated on
to the top of the fresh fuel, and distils the gases from the same, whilst the air
passing through the apertures or perforations in these flues, effects the perfect
combustion of these gases. I prefer to arrange the said air flues. or passages
in such a manner that the air passes into them from the ash-pit or space
below the fire-bars, whereby the quantity of air that impinges on to the top of
the fire will increase in proportion as the quantity that passes through the
fire-bars diminishes, and vice versa, and thus the apparatus is rendered self-

page_text: regulating without any additional mechanism being requisite for. this purpose.
In some cases, however, I do not make the air flues or passages communicate
with the ash-pit, but conduct the air into them in any other convenient
manner, and in some cases I provide dampers or valves to these air flues to
regulate at pleasure the quantity of air that impinges on to the top of the fire.
The form, number, and arrangement of these air flues or passages, as also
of the apertures through which the air passes from them on to the fire, may
be, variously modified according to the requirements of the fuel employed, and
.the nature of the furnace to which they are applied.. Thus in one arrangement
I mould them in blocks of fire-clay, which form more or less a complete
lining to the fire-box, and in some cases I extend such air flues beyond the
fire-box or space immediately over the fire-grate, so as to act upon any com-
bustible gases that may have passed away from the fire unconverted. In other
cases I line the fire-box or space above the fire-grate only partially with such
air flues, and in some cases I cause the flame and products of combustion to
pass both. underneath and over the top of such air flues, in which case they
may be pierced on top and bottom, if found convenient, and be supplied with
air from the front, or sides, or from the ash-pit at bottom.
Figures 1 and 2 on the accompanying Drawing, shew one arrangement of
my Invention as applied to the furnace of a Cornish boiler. Figure 1'shews a
transverse section, and Figure 2 shews a part longitudinal section.
open and com-
A, A, is the shell of the boiler; B, B, are the furnace bars; C is the
bridge. On either side of the furnace bars are fixed supports D, D, having
openings d, d, which supports carry the fire-brick lining E, in which are
formed the channels e, e, e, the lower extremities of which are
municate with the space beneath the fire-grate or ash-pit F. The backs of
these channels are closed by the shell of the boiler flue, as shewn; whilst in
front, over the fire-grate, they communicate by means of small openings or
slits e, e', with the space above the fire-grate. By this arrangement, when the
fire is burning on the grate, atmospheric air will pass into the channels e, e,
from the ash-pit. F, as shown by the arrows, and will pass thence in small jets
through the openings e¹, e¹, on to the top of the fire, and the combustible gases
that are passing off from the fuel unconsumed will, by the combined action of
these jets of air and of the heat radiated down from the material in which the
air channels are formed, become more or less perfectly consumed, and by their
combustion, will naturally cause a greater amount of heat to be generated
from a certain quantity of coal than would be the case under ordinary
-circumstances.

page_text: Another advantage arising from this improved arrangement is, that the heat
from the furnace is more uniformly distributed over the heating surface of
the boiler instead of being principally concentrated at the part situated imme-
diately over the furnace, as the air in passing through the channels e, e, and
apertures e, e, continually takes up a portion of the heat that is absorbed by
the fire-brick lining E, and thereby prevents the shell of the boiler at that
part from being deteriorated from the excess of heat that ordinarily strikes
against it. The heat so taken up by the air in passing through the channels
is in no way. lost, as it is usefully employed in causing the more perfect com-
bustion of the gases and the decrease in the amount of heat that is passed
through that part of the shell of the boiler flue situated over the fire-
grate is greatly exceeded by the increase of heat in the other parts of the
boiler flues.
Although the fire-brick lining E, with the air channels e, is shewn only
extending as far as the fire-bridge C, yet in some cases I extend the lining
beyond the bridge, and instead of making the air channels e, e, in a transverse
direction, as shewn, they may run in a longitudinal direction, and the air may
enter them in front of the boiler. In some cases also, instead of lining the
space over the furnace completely with such air flues, I only line it partially
with the same. Although in adapting this arrangement of my Invention to
furnaces in present use, the area of the fire-grate is somewhat diminished, yet
the amount of heat produced from the smaller quantity of fuel will more than
equal that produced before by the greater amount of fuel on account of the
more perfect combustion of the same. The same quantity of fuel may, however,
be used in this arrangement as was used before, as, on account of the more
perfect combustion, the fire. may be made of a greater depth than before: 'I
sometimes from. the lining E with the air channels e, e, of cast iron instead of
fire-brick, in which case it would be of a less thickness and would consequently
not take up so much space in the furnace.
•
Figure 3 shows a transverse section through a Cornish boiler with another
modification of my Invention. In this arrangement, instead of forming a
number of air channels in a lining of fire-brick over the furnace, as just
described, I arrange a lining of sheet iron E in the boiler flue A over the
furnace in such a manner as to leave a space e, e, between it and the boiler
Alue, which space constitutes the air flue, and whence the air passes into the
space over the top of the fire-grate in small jets through the holes or
perforations e, el, formed in the lining E; this lining is carried by supports D, D,
of fire-brick or other suitable material. In this arrangement, as shewn, the

page_text: air passes into the space e, e, from the ash-pit I, as shewn by the arrows, but
the air may also be caused to enter the same from the front of the boiler. This
just described arrangement would possess the advantage over the first described
one of not taking up so much space of the fire-grate...
Figure 4 shows a longitudinal section, and Figure 5 shews a part transverse
.section of a marine boiler, having another modification of my Invention. In
tbis arrangement the air passages are made in the form of wrought-iron tubes
or chambers E, E, communicating with the external air in front of the boiler,
as shown by the arrows, and attached by means of bolts G, G, to the casing
of the boiler flues; they are formed by preference gradually tapering towards
the inner end, as shewn, and are arranged so that they can at any time be
withdrawn. The. air passes from the inside of these tubes in small jets on to
the top of the fire through the small apertures e¹, e¹, and thus causes, as before
described, the combustion of the gases that otherwise pass away from the 'fuel
☐ unconsumed. In this arrangement it. will be observed that the space of
the fire-grate B is not at all encroached upon by the air tubes E, E.
In some cases.I arrange these tubes as a close partition in the boiler flue
so as to form a return flue between their upper surface and the surface of the
boiler flue, and I then also form the air holes e¹, e¹, in the upper surface of
the tubes.E through which the air passes in small jets, and, coming in contact
with the flames and hot gases; causes their still more perfect combustion, and
consequently a still greater developement of heat. Instead of employing
several air tubes E, E, as shewn, I sometimes form them into one tube, and I
.either leave the ends in the front of the boiler quite open, as shewn, or I
provide them with valves or dampers so as to regulate at pleasure the quantity
of air that passes on to the top of the fire.
Figure 6 shews a part longitudinal section through a boiler with another
modification of my Invention. In this arrangement the air passage e is
formed by placing a hollow iron shield E, having a water space, as shewn, a
short distance from the top of the boiler flue A over the furnace. The air
passes from the passage or chamber e in small jets. on to the top of the fire
through small tubes e¹, e', fixed in a water-tight manner in the shield E, and
passing through the water space of the same. The water space of the
shield E communicates by means of tubes H, H, with the interior of the
boiler, by which means circulation is established, and the shield E prevented
from becoming heated to an injurious degree; the tubes H also serve to carry
the shield E. The end and sides of the air passage e formed by the latter
may be closed up by means of fire-clay. In some cases I form the air flue

page_text: or chamber e in the water space of the boiler itself in the form of a tube
closed at the inner extremity, and situated above or at the side of the boiler
flue, and I cause it to communicate with the furnace through small tubes
passing through the shell of the boiler.
Figure 7 shews a part longitudinal section through the boiler of a loco-
motive engine with another modification of my Invention adapted to the fire-
box of the same. In this arrangement the air channels or passages e, e, are:
formed in the shield E of fire-brick or other material projecting from below
the tubes a, a, at the back of the fire box A to any convenient distance over
the fire-grate B. Small apertures e¹, e¹, are formed both in the under and
upper side of the channels e, e, through which the external air passing into
the channels e, e, from apertures in the sides of the fire-box, is caused to
impinge in small jets both on to the top of the fire and on to the gases passing
over the top of the shield E into the tubes a, a, and, in combination with the
heat radiated from the shield E, causes the more perfect combustion of such
gases.
Figure 8 shews a section through a "hot plate" to which my Invention is
adapted. A is the "hot plate;" B is the fire-grate; C, C, are the flues for
the passage of the flames and hot gases. In this arrangement a chamber-E
is, firstly, formed on the under side of the cover D, into which the external air
passes from the opening d, and whence the air impinges in small jets on to
the top of the fire through small apertures e¹, e. Furthermore, other air pas-
sages E, E, are formed over the top of the flues C, C, on either side of the
fire-place, having small openings e, e, through which the air passes in small
jets, and, mixing with the unconsumed gases as they pass away from the fire,
cause their more perfect combustion.
Having now described the nature of my Invention, and the best means I
am acquainted with of performing the same, I wish it to be understood that
I in no way limit myself to the various arrangements of my Invention, as
herein before described, with reference to the accompanying Drawing, as the
arrangement of the air passages, chambers, or flues, may be variously modified
without departing from the nature of my Invention, and they may be applied
to various other descriptions of furnaces or fire-places than those herein-
before set forth; nor do I claim generally the the introduction of small jets of
atmospheric air into the space above the fire-grate of furnaces; but what I
claim, is,-
Firstly, providing furnaces with air flues, passages, or chambers formed in
fire-clay or other suitable material, and having small apertures or slits com-

page_text: municating with the space above the fire-grate, through which flues, passages,
or chambers the external air is caused to pass, and to impinge in small jets
on to the top of the fire, substantially as herein-before described with reference
to the accompanying Drawing.
Secondly, effecting the more perfect combustion of the fuel in furnaces by
the combined action of jets of atmospheric air passing through flues or pas-
sages formed over the top of the fire, and the heat that is radiated from the
material in which such flues or passages are formed.
In witness whereof, I, the said Samuel Hazard Huntly, have hereunto
set my hand and seal, this Fifteenth day of December, in the year of
our Lord One thousand eight hundred and sixty-two.
SAMUEL HAZARD HUNTLY. (L.S.)