IMPROVEMENTS IN APPLYING HEAT TO THE MANUFACTURE OF ALKALIES AND SALTS, AND FOR SMELTING AND OTHERWISE WORKING ORES, METALS, AND EARTHS
Year: 1838

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
FLUDE, of Long Lane, Bermondsey, in the County of Surrey, Manufacturing
Chemist, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Letters Patent under the Great Seal of Great Britain, bearing date at West-
minster, the Thirtieth day of January, in the first year of Her reign, did, for Her-
self, Her heirs and successors, give and grant unto me, the said Charles
Flude, Her especial license, full power, sole privilege and authority, that
I, the said Charles Flude, my exors, adiñors, and assigns, or such others
as I, the said Charles Flude, my exors, adiñors, or assigns, should at any
time agree with, and no others, from time to time and at all times during
the term of years therein expressed, should and lawfully might make, use,
exercise, and vend, within England, Wales, and the Town of Berwick upon
Tweed, my Invention of "IMPROVEMENTS IN APPLYING HEAT TO THE MANUFACTURE
OF ALKALIES AND SALTS, AND FOR SMELTING AND OTHERWISE WORKING ORES, METALS,
AND EARTHS;" in which said Letters Patent is contained a proviso that I, the said
Charles Flude, shall cause a particular description of the nature of my said'
Invention, and in what manner the same is to be performed, to be inrolled
in Her said Majesty's High Court of Chancery within six calendar months next
and immediately after the date of the said in part recited Letters Patent, as'
in and by the same, reference being thereunto had, will more fully and at large
anneer

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Flude, do hereby declare the nature of my said Invention, and
the manner in which the same is to be performed, are fully described and
ascertained in and by the following statement thereof, reference being had to
the Drawing hereunto annexed, and to the figures and letters marked
thereon, that is to say:-
My Invention relates to modes of applying coke ovens to the purposes of
the manufacture of alkalies and salts, and smelting and otherwise working ores,
metals, and earths, whereby in addition to the coal giving off the requisite quantity
of heat for carrying on such manufacture the useful product of coke is obtained
from the coal, in place of using such coal in the ordinary fire-places or furnaces,
where destructive combustion of such fuel is the result of the working; and I
would in the first place state, that I am aware that attempts have been made to
apply coke ovens to some of the manufactures above-mentioned; I do not,
therefore, claim such application generally, but only under such circumstances
as hereafter explained; and in order to give the best information in my power,
I will in the first place give such information as to the general working of coke
ovens, and of their application to the manufactures to which my Invention
relates, that a workman conversant with the furnaces and apparatus used in
such manufactures will readily adapt my Invention to a particular manufac-
ture; and I may here observe that, as my Invention only relates to certain
modes of applying coke ovens in substitution of the ordinary furnaces or fire-
places of the various processes above-mentioned, and does not further interfere
with the processes themselves, it will not be necessary to enter into a descrip-
tion of such processes, they being well understood; but confine my description
to the nature and application of coke ovens according to my Invention.
I will now proceed to describe the mode heretofore used in the manufacture
of coke, in order to point out and explain in what respect my Invention differs
from the plan hitherto pursued. I will also point out the purposes to which
the waste heat of coke ovens have hitherto been applied. Two modes have
hitherto been employed in the manufacture or production of coke. One mode
consists of igniting or burning large quantities of coal or slack (small coal) in
the open air, as is well known in various parts of this country. The other and
more usual mode is to ignite, carbonize, or distil coal or slack (small coal) in
brick ovens, generally of a circular or oval form, provided with a brick floor
and a low brick arch, and surmounted with a short chimney. These furnaces
or ovens are furnished with one or more doors, according to their size, for intro-
ducing the coal to be converted into coke. These doors are generally made of
iron, sliding in iron frames, and counterpoised by a weight attached to a chain

page_text: passing over a pulley, or are sometimes raised by an iron lever, as is usual with
heavy furnace doors. The size of the ovens and the thickness of the walls
varies considerably in different parts of the country; in some instances the
walls are built double, and the interval filled with sand or earth; the usual
dimension of the furnace is about twelve feet by six, and the height of the arch
in the centre three to six feet from the floor. The size, however, varies con-
siderably: in some instances they are built much smaller than the above; but'
the preference is generally given to the larger; the chimney is generally from
eighteen inches to three feet square, the flue being nine to eighteen inches
square, and furnished with a damper to regulate the draught.
Having thus described the construction of a coke oven as hitherto built, I shall
now proceed to point out the manner in which they are used, in order to explain
the nature of those improvements, by means of which I am enabled to render
the coke oven capable of performing processes by the waste heat, which it has
hitherto been deemed incompetent to effect. The oven when first used re-
quires to be heated to redness, by means of wood, coal, slack (small coal), or any
other convenient fuel. When this is effected the ashes, cinders, &c. are raked
out by a suitable instrument, and the coal or slack is then thrown in as quickly as
possible (the quantity varying from one to five tons), and the door being closed
the oven is left to itself for twenty-four to thirty-six, or even fifty hours,
according to the quantity of coal employed. When the volatile or gaseous
matters of the coal being all dissipated, the cokes are drawn out by a rake or
by an iron peel (similar in form to that used by bakers for drawing bread, but
of a larger size), and a fresh charge of coal is thrown in when the door is closed,
and the process goes on as before. The application of the waste heat of such
ovens has hitherto been very limited from the circumstance of the great quan-
tity of smoke given off, and the inequality and irregularity of the heat, which,
though strong for a limited portion of the time occupied in the carbonization
of the coal, could not be kept up and maintained, which circumstance renders'
it inefficient for the greater part of the processes enumerated in my Specifica-
tion, had the application been proposed. The processes to which, however, it'
has been applied are the following, videlicet, the burning of lime by attaching
a cone or kiln to the ovens, and allowing the flame, smoke, and hot air to pass
through the chalk or limestone placed in the same, which cone became the
chimney.
The lime so produced is known by the name of "flame lime," and is con-
sidered much superior to the lime produced in the ordinary way.
Coke ovens
have also been employed for heating gas retorts, and for the manufacture of
charcoal and acetic (pyroligneous) acid, by the destructive distillation of wood,

page_text: and for the manufacture of animal charcoal and ammonia by the destructive
distillation of bones; also for the manufacture of the salts known as the sul-
phate and muriate of ammonia or sal ammoniac, and for the distillation of oil
of vitriol..
. It has also been tried, but abandoned, for the following purposes; namely,
in the manufacture of common salt, salt cake (sulphate of soda), and alkalies;
but has now been entirely relinquished for such purposes, on account of the
want of control and irregularity of the heat, and for other causes which rendered
it inefficient and inelligible.
Having shewn the nature, construction, and use of coke ovens as hitherto em-
ployed, and to what extent the waste heat has been rendered available for manufac-
tory purposes, I shall now proceed to explain the nature of my improvements, by
which I have been enabled to extend its application and utility to purposes for
which it was before incompetent.
The outward and general appearance of
my ovens differs but little from those already in use, for some of the purposes
for which the waste heat has been already applied, as before described, par-
ticularly those employed in the manufacture of charcoal and acetic acid; (that
is to say,) there are of a square or oblong form, and consist of four walls lined
internally with fire bricks, a brick or tile floor, and a brick arch; the arch,
however, in ovens, according to my Invention, are generally higher from the
floor than in the usual construction of coke ovens; the size varies with the
nature of the operation the heating process is required to perform; the size,
however, to which I generally give the preference is about seven feet by five
internal measurement, that is to say, seven feet from front to back, and five
feet from side to side; the side walls are two and a half bricks thick, or
twenty-two inches, and the front and back walls two bricks or eighteen inches.
This, however, will be better understood by reference to the Drawing. Figure 1
shews a horizontal plan of the oven, floor, and the walls. This sized oven is
charged with about a ton of coals or slack (small coal) more or less, and is
what I denominate "a ton oven," and is, in my opinion, the most useful size
for general purposes. I do not, however, confine myself to this size, as where
very strong heats are required, as for smelting purposes, I generally use them
of a larger size, say eight feet by six, according to local circumstances, and
for those operations which require the heat to be diffused over a very large
space, as in the manufacture of common salt, I prefer using two or more
ovens to each pan, but of a smaller size. Indeed, it will generally be found
most advantageous to work them in pairs, either side by side or end to end,
according to situation, as shewn in Figures 2 and 3; the letter a shows the
door of the oven, and 6 the fire-bridge or exit flue.

page_text: The oven and chamber are each covered in with a nine inch arch, built with
fire bricks, surmounted by three counter arches of common bricks; in the fire
arch the bricks are placed on end or lengthwise, but in the three counter
arches the bricks are placed on edge, or four inches and a half thick, making
what is called a fourteen inch arch together; the object of these counter arches
is to retain the heat. The top arch may also be covered with sand or shingle to
confine the heat more effectually. "a" shews the door of the oven, which I
generally build twenty-two inches square in the front opening, but splayed out
or widening internally; this is for the convenience of raking out and with-
drawing the coke; this opening I close when the oven is at work by a twenty-
four inch fire tile, banded with iron to strengthen it in case of cracking;
this tile door will be found to retain the heat in the oven better than the iron
door usually employed; this door may be raised by a chain and iron lever, as
before described, or it may be furnished with projecting handles, and moved
aside by hand; "6" is the fire-bridge or flue, through which the flame and
heated air passes into the laboratory or chamber; this flue I build large, say
about thirty-six inches wide by about twelve inches deep; the side walls I
build two bricks and a half thick, or twenty-two inches, and the front and back
walls two bricks thick, or eighteen inches; and I prefer carrying up or building
the front and back walls somewhat above the height of the crown of the arch,
as shewn in the Drawing, and forming the arch of the exact length of the clear
space between the said walls, say seven feet, as shewn in the Drawing; the
arch is thus made independant of the front and back walls, taking no bearing
upon them, and is built with a straight joint (front and back,) bearing only on
the side walls, in which are formed the "skew" "backs," as they are denomi-
nated by the workmen. The side walls are strengthened and secured by brick
battering pillars or buttresses, or by iron rods or bars passing across the top of
the arch, and by iron wall plates screwed up to the rods by nuts, as is usual in
tying in or bracing large furnaces. I prefer using inch square wrought iron
rods, in which a strong thread is cut at each end; the said ends being passed
through holes in the wall plates, which may be of wrought or cast iron of the
usual size and dimensions, passing down from the top of the ovens to the
ground into which they are inserted about nine inches deep, and rammed up
close to the wall for the more securely bracing the work; the top of each wall
plate is then screwed up to the transverse tye bar by iron nuts cut to fit the
thread before described. I generally use two tye-bars and four wall plates to
each oven, when built singly. The height of the crown of the arch from the
floor is five feet (more or less) internal measurement; the floor is raised about
twelve inches above the ground, and is built of three courses of bricks laid flat,

page_text: and covered by a course of bricks set on edge. I generally use commn bricks
for the floor, the same being placed lengthwise with the oven, as shewn in
Figure 1; the front and back walls are about eight feet in height, and the
skew backs in the side walls about four feet nine inches, as I prefer giving the
arch a rise of about fifteen inches to increase its strength. When the arches
are finished I carry up the side walls to the same height as the front and back,
being about twelves inches higher than the top of the arch, to retain the sand
or shingle before described, for the more effectually confining the heat. D is
an opening furnished with a projecting shelf of fire tile or of cast iron-I prefer
the latter; this opening is about nine inches high and fifteen inches wide, and
is used as a feeding hole or hopper to regulate the heat, being stopped up with
small coal or slack, as is usual with the reverberatory furnaces of the ordinary
construction; this feeding ho or hopper furnishes the means of increasing
and regulating the heat, and is used thus:-When the bituminous matter of
the coal originally charged or thrown upon the floor of the oven for carboniza-
tion or coking is nearly burnt off, and the flame begins to diminish and weaken
in intensity, the flame is increased by the workman pushing down the coals
in the hopper from time to time with a rake made for that purpose, and care-
fully refilling the hopper with fresh coals to be used as occasion required. This
opening may be made in the front wall over the oven door, or in the side wall,
according to local circumstances. When much heat is required, I construct
two hoppers to each oven; when it is requisite (as is the case with some opera-
tions) to reduce and lessen the heat, the workman adjusts the coals in the
hoppers, so as to allow a larger quantity of cold air to enter the oven, or the
said hoppers may be entirely cleared of coals for the same purpose, leaving the
whole free space open for the cold air to rush through. This constitutes the
second part of my Invention when applied to the purposes named, and in the
way described, the same never having been before used as a means of increasing
and regulating the heat of a coke oven for manufacturing purposes.
Mode of conducting the hot air flues.-Figure 4 is a longitudinal section of
one of the side walls of the oven, shewing also a transverse section of the front
and back walls, with the bridge or fire flue, and describing the direction of the
hot air flues. A is the oven floor, formed as before described with two (or more)
courses of bricks laid flat, surmounted with a course of bricks laid edgewise;
B shews, the fire arch, and the three counter arches; "6" is the fire bridge or
exit flue, through which the flame, smoke, and hot air passes out of the oven.
The air necessary to support the combustion of the gases evolved and given off
by the coals enters by the air flue "d," and passing through and along the side
wall, and about half way through the end or back wall. The flue "k" shews

page_text: the outlet for the hot air; this outlet is separated from the fire bridge by a
covering one brick thick, so that the air, having traversed an extensive heated
surface, rushes out at or under the fire bridge, and effects the combustion of the
whole on the greater part of the smoke given off by the coal."
Although I have been thus particular in describing the nature of the coke
ovens as applied by me to the manufactures herein stated, and have given full
information for constructing the air flues by which the coke oven or the fluo
thereof near the bridge is supplied with heated air, by which the black
and dense smoke or vapours are ignited, and thus beneficially used in
obtaining heat for the purposes of the above manufactures; and although I
have only given Drawings of some of the construction of furnaces used in the
processes of applying heat to the manufacture of alkalies and salts for
and smelting and otherwise working ores, metals, and earths, I have
simply given them as examples; but the workman will readily be able
from such description, aided by the particular description given of what
I consider the best arrangement of air flues for heating the air supplied to the
coke oven, or to the fire bridge thereof, and also the hopper to be used accord-
ing to my Invention, will readily be able to adapt a coke oven to the particular
process he desires in substitution of the ordinary furnace or fire-place before
employed for the same process; and altho' I prefer the application of heated
air at or about the bridge, I do not confine myself thereto, as hot air may be
applied to coke ovens, so applied to the particular manufacture above mentioned,
at other places with a beneficial result.
Having thus described the nature of my Invention, and the manner of per-
forming the same, I would have it understood that what I claim as my Inven-
tion is, first, the application of coke ovens when combined with means for
supplying heated air thereto or to the flue thereof to the process herein ex-
plained. Secondly, I claim the application of a hopper or hoppers to a coke
oven when applied to the purposes above described; and, thirdly, I claim the
application of coke ovens to salt pans for making salt, when such ovens are
applied in a position not under the pan, but only given off heat thereto by flues
passing under the pan, whether such application be accompanied or not by th
se of heated air or hoppers, as above described.
In witness whereof, I, the said Charles Flude, have hereunto set my
hand and seal, this Thirtieth day of July, One thousand eight hundred
and thirty-eight

page_text: AND BE IT REMEMBERED, that on the Thirtieth day of July, in the
year of our Lord 1838, the aforesaid Charles Flude came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.