IMPROVEMENTS IN ECONOMISING FUEL
Year: 1855

page_text: LETTERS PATENT to Frank Clarke Hills, of the Chemical Works, Dept-
ford, for the Invention of "IMPROVEMENTS IN ECONOMISING FUEL."
Sealed the 14th March 1856, and dated the 26th December 1855.
PROVISIONAL SPECIFICATION left by the said Frank Clarke Hills at
the Office of the Commissioners of Patents, with his Petition, on the
26th December 1855.
I, FRANK CLARKE HILLS, of the Chemical Works, Deptford, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN ECONOMISING FUEL"
to be as follows:-
My Invention consists in the employment of steam mixed with atmospheric
air, preferably heated, as a supporter of combustion. The steam coming in
contact with the ignited fuel in the furnaces is decomposed; its oxygen uniting
with the carbon of the fuel employed, and its hydrogen uniting with fresh
oxygen, a very intense heat is produced, and a considerable quantity of fuel,
saved.
This Invention is more particularly applicable to furnaces in which coke is
burnt and a white or high heat obtained, such as locomotive engine furnaces,
gas retort furnaces, iron smelting or melting furnaces, &c. &c., and especially
where the steam can be obtained by waste heat or as a waste product.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frank Clarke Hills in the Great Seal Patent Office on the
24th June 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANK
CLARKE HILLS, of the Chemical Works, Deptford, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of December, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Frank Clarke Hills, Her special licence that I, the said Frank Clarke
Hills, my executors, administrators, and assigns, or such others as I, the
said Frank Clarke Hills, 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 "IMPROVE-
MENTS IN ECONOMIZING FUEL," upon the condition (amongst others) that I, the
said Frank Clarke Hills, my executors 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 Frank Clarke Hills, 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, that is to say :-
My improvements in economizing fuel are particularly applicable to furnaces
where a white or very high heat can be obtained, such as gas retort furnaces
or locomotive engine furnaces; but they are also adapted for steam boiler and
other furnaces, especially' when steam can be obtained as a waste product,
or when by waste heat steam can be obtained or be superheated.
My improvements consist in the employment of steam mixed with atmo-
spheric air, preferably heated, for supporting combustion, and in certain
arrangements of furnaces for that purpose, and which furnaces are also well
adapted for the prevention of smoke even when steam is not employed, in
which case the closed ash-pit described will not be necessary.
I now proceed to describe the mode in which I carry out my Invention.

page_text: A furnace is to be constructed of any convenient size and shape, furnished
with hollow fire bars, by which I mean fire bars having longitudinal openings
through them from end to end like pipes; these bars are to be used instead of
the solid bars usually employed, only instead of having round holes through
them; the holes should correspond to the shape of the bars. A hanging bridge
or arch, composed of fire lumps or bricks, or other suitable material, is to bo
placed over and across the fire bars from side to side of the furnace at a
suitable height, and fitting the under side of the boiler or top of the furnace,
and about one-third of the length of the bars, in front of the back end or
bridge of the furnace; or a pocket or channel may be made in the boiler to
form the said bridge. The back of the furnace is to be formed of what is
called a split bridge, which is a bridge with a slot or opening, or with more
than one opening, in the brickwork across the back of the furnace. Commu-
nicating with this slot or with these openings is a chamber, into which the
ends of the hollow fire bars are closely fitted, so as to exclude any air from,
entering the split bridge excepting that which passes through the hollow bars,
the front ends of which are open to the atmosphere. The lower part of this
slot or opening in the bridge should open into the back end of the ash-pit, for
the purpose of cleaning out any dust, &c. that may drop through the split
bridge, and this opening into, the ash-pit must, except when being cleaned out,
be closed by a valve or door. A number of small holes, slots, or openings are
to be made in the fire door, or dead plate, or front part of the furnace. The
ash-pit is to be closed in front, instead of being open as usual, but having a
door for cleaning out the ashes; a pipe for admitting air, with a steam jet pipe,
in the middle of it, is to be fixed in the front of the ash-pit above the door for
cleaning out the ashes. The; furnace being prepared as above, a fire is to be
lighted on the hollow fire bars, and the ash-pit door is to be left open until the
fire has become bright and clear; the ash-pit door is then to be shut, and stean
is to be admitted through the jet into the ash-pit; the jet of steam will draw
air in with it through the air pipe into the ash-pit, and the air and steam will
be there well mingled together, and will then pass upwards between the fire
bars and through the red or white hot fuel on them, and the steam will be
decomposed; the hydrogen of the steam mingled with other gases which bave
not undergone complete combustion will, on arriving at the top of the fuel,
meet fresh atmospheric air, which is admitted into the furnace through the
small holes or openings, before described, in the fire door or front part of the
furnace, and the whole will then be deflected by the arch or hanging bridge
on to the hottest part of the fuel, at the back of the furnace, when the. hydrogen
from the decomposition of the steam, and any other unburnt gases or

page_text: carbonaceous matter, will meet with the hot air which has passed through the
hollow fire bars, and up through the slot or split bridge, before described, by
which a perfect combustion of the whole will be effected. A cock should be
attached to the steam jet pipe to regulate the quantity of steam to be admitted,
and a regulator or valve should be attached to the pipe admitting the air to
the ash-pit to regulate the quantity of air to be drawn in by the jet of steam,
and no more air should be admitted than is sufficient to keep up the requisite
heat. The size of the steam jet and air pipe will of course depend upon the
size of the furnace and the pressure of the steam used, for the lower the
pressure of the steam the larger must be the orifice of the jet. I have found
a steam jet pipe with an eighth of an inch aperture, placed in the centre of an
air pipe three or four inches diameter, and about a foot long, to answer very
well for a three-horse power steam boiler, when the steam is admitted into the
ash-pit at about 20 lbs. pressure on the square inch. For decomposing the
steam perfectly, the fuel through which it passes should be of a considerable
depth, and the larger the pieces of coke or other fuel used, and the larger the
interstices between them are, the greater should be the depth of the fuel; it
should in no case be less than fifteen inches, but three or four feet deep would
be better, and the area of the furnace should be proportionably contracted;
steam admitted through thin fires is not decomposed, and consequently will not
make a saving of fuel, although it may to some extent condense smoke and
increase draught. It is not absolutely necessary that the ash-pits of the
furnaces should be closed, and that the steam and air should be forced in, as a
considerable quantity of steam may be caused to pass into the ash-pit, and
thence through the ignited fuel on the bars by the draught of the chimney; but
in this case the front of the ash-pit should be closed from the fire door down-
wards to within a few inches of the bottom of the ash-pit, leaving an opening
there for the admission of air, and so forming a vault above; but by this
means the admission of air cannot be so well regulated as when the jet and
air pipe are used. If steam is not employed in the said furnaces the fuel on
the bars should be much thinner, and it will not be necessary to close the ash-
pits in front. I believe that steam has been employed in various ways in
ordinary or common furnaces for increasing the draught and for condensing
smoke, and therefore I do not claim its use for these purposes; but what I
clain as my improvements are,―
First, passing air and steam into closed or partially closed ash-pits, and then
well mingled through fuel of such a thickness or depth, placed in furnaces so
constructed and at such a heat as to effect a perfect or nearly perfect decom-
position of the steam.

page_text: Second, I claim the construction or arrangement of the furnace described,
and especially the combination of hollow fire bars, in furnaces with a hanging
bridge, by which means the air is heated and brought in contact with the other
gases in the furnace, and thereby effecting a very perfect combustion; and
I make this claim whether steam is used or not, as the furnace is well adapted
for the combustion of fuel without causing smoke.
In witness whereof, I, the said Frank Clarke Hills, have hereunto set
my hand and seal, this Twenty-fourth day of June, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
WILLIAM GASTINEAU.
F. C. HILLS. (LS.)