IMPROVEMENTS IN APPARATUS FOR RE-BURNING ANIMAL CHARCOAL
Year: 1861

page_text: LETTERS PATENT to John Cowan, of the Firm of L. Cowan and Sons, of
Barnes, in the County of Surrey, Animal Charcoal Manufacturers, for
the Invention of "IMPROVEMENTS IN APPARATUS FOR RE-BURNING ANIMAL
CHARCOAL."
Sealed the 10th December 1861, and dated the 26th June 1861.
PROVISIONAL SPECIFICATION left by the said John Cowan at the
Office of the Commissioners of Patents, with his Petition, on the 26th
June 1861.
I, JOHN COWAN, of the Firm of L. Cowan and Sons, of Barnes, in the
County of Surrey, Animal Charcoal Manufacturers, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN APPARATUS FOR RE-BURNING
ANIMAL CHARCOAL," to be as follows:-
An important object in re-burning animal charcoal consists in preserving it
from the atmospheric air when to be removed from the cylinder, chamber, or
retort. For this purpose instead of having to remove the whole end or cover
to withdraw the contents as usual, thereby allowing a full and continuous rush
of air, I form in the front or discharge end or cover an opening, which only
occupies a limited or restricted portion thereof, and is closed as required by a
door, lid, or plate, which, when the charcoal is to be discharged, is opened, only
exposing a small portion of the interior, preserving the mass from being
decomposed by rush of air, and only allowing a small quantity of air, if any,

page_text: to get access to the products to be discharged. I support the cylinder or retort
on wheels or rollers, on which it turns, preferring to have two such wheels or
rollers at each end, and to form the front end or cylinder cover with a flange
broader than the rim of its supporting wheel (to allow for expansion), and
preferring to cause the flange at the back end to turn in a groove in its
supporting wheels, to keep that end in gear with the driving arrangements. I
drive or turn the cylinder or retort by forming or fixing teeth, or a cogged or
toothed wheel, rim, or flange on one end, which I drive by a pinion or
equivalent on a driving shaft, so that by having a number of pinions or wheels
at intervals on a main driving shaft lying horizontally along the back ends of a
row of cylinders or retorts placed side by side, and having toothed wheels or
flanges on such ends, any desired number of cylinders may be driven by the
same shaft. By the means above described the chains and girders hitherto
used may be dispensed with. The cylinders or retorts are mostly formed with
double plates or covers at the ends, having a space between those of each end.
I fill such space with fire-brick, or other non-conducting media, to prevent
radiation of heat at that part. Instead of employing a furnace to each moving
or revolving cylinder or retort, I sometimes construct an arch or chamber of
sufficient span or size to receive or contain more than one such cylinder or
retort; or I construct a series or set of two or more arches or chambers, so
connected one with the other, that the fire of one furnace may impart its heat
to more than one such cylinder or retort.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Cowan in the Great Seal Patent Office on the
26th December 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
COWAN, of the Firm of L. Cowan and Sons, of Barnes, in the County of
Surrey, Animal Charcoal Manufacturers, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of June, in the year of our Lord
One thousand eight hundred and sixty-one, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Cowan, Her special licence that I, the said John Cowan, my
executors, administrators, and assigns, or such others as I, the said John
Cowan, 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

page_text: 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 APPARATUS FOR
RE-BURNING ANIMAL CHARCOAL," upon the condition (amongst others) that I,
the said John Cowan, 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 John Cowan, 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, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say:-
This Invention has for its object improvements in apparatus for re-burning
animal charcoal. An important object in re-burning animal charcoal consists
in preserving it from the atmospheric air when it is to be removed from the
cylinder or retort. For this purpose instead of having to remove the whole
end or cover (of the cylinder or retort), in order to withdraw the contents, as
is usual, thereby allowing a full and continuous rush of air, I form in the front
or discharge end or cover an opening, which only occupies a limited or
restricted portion thereof, and is closed as required by a door, lid, or plate,
which, when the charcoal is to be discharged, is open, thereby only exposing a
small portion of the interior, preserving the mass from being decomposed by
the rush of air, and only allowing a small quantity of air, if any, to get access
to the products to be discharged. I support the cylinder or retort on wheels
or rollers, on which it turns; I prefer to have two such wheels or rollers at
each end of the cylinder, and to form the front end or cylinder cover with a
flange broader than the rim of its supporting wheels (to allow for expansion),
and I also prefer to cause the flange at the back end of the cylinder to turn in
a groove in its supporting wheels, to keep that end in gear with the driving
arrangements. I drive or turn the cylinder or retort by forming or fixing
teeth, or a cogged or toothed wheel, rim, or flange on the end, which I drive
by a pinion or equivalent on a driving shaft, so that by having a number of
pinions or wheels at intervals on a main driving shaft lying horizontally along
the back ends of a row of cylinders or retorts placed side by side, and having
toothed wheels or flanges on such ends, any desired number of cylinders may
be driven by the same shaft. The cylinders or retorts are mostly formed with

page_text: double plates or covers at the ends, having a space between those of each end.
I fill such space with fire-brick, or other non-conducting media, to prevent
radiation of heat at that part. Instead of employing a furnace to each moving
or revolving cylinder or retort, I sometimes construct an arch or chamber of
sufficient span or size to receive or contain more than one such cylinder or
retort; or I construct a series or set of two or more arches or chambers, so
connected one with the other that the fire of one furnace may impart its heat
to more than one such cylinder or retort.
I now proceed with reference to the accompanying Drawings to describe
in what manner the Invention may best be carried into practical effect.
Figure 1 is a front end elevation of a furnace containing, for example, two
cylinders or retorts, though a single cylinder or retort or a larget number than
two may be fitted in the furnace; Figure 2 is a back end elevation, and
Figure 3 a transverse vertical section of the same; Figure 4 is a longitudinal
section taken through one of the cylinders or retorts.
A, A, is the brickwork of the furnace; B, the furnace door; C, the ash-pit.
The fire-bars are not shown, but are constructed and supported as usual.
D, D¹, are two retorts or cylinders. Retorts of the description shown, being
generally of cylindrical form, are mostly called "cylinders." The cylinder D
is shewn as open and the cylinder D¹ as closed.
I before stated that heretofore in the usual mode of constructing these
cylinders or retorts the front end or cover, that is, the cover of the discharge
end is so arranged that it must be taken completely off when the cylinder is to
be opened in order to discharge the contents; thus the whole end is thrown open
from top to bottom and from side to side, so that the atmospheric air rushes
forcibly and continuously over and into the mass of charcoal in the cylinder,
and decomposes and injures the same, whereas, according to my Invention, I
construct the front or discharge end plate or cover E as a fixture bolted or
otherwise secured to the body of the cylinder or formed in a piece therewith,
and at its lower part I construct an opening F, which only occupies a portion
of the end plate or cover and does not even reach up to the centre thereof nor
extend laterally to the periphery of the plate. This opening is carefully closed
while the operation of reburning is proceeding, by a door G which is fastened by
bolts H, which bolts pass at each end through staples or eyes I fixed to the
cylinder end, and are secured by screws J. When the contents of the cylinder
are to be discharged the door G is unfastened and removed, whereby only a
small portion of the interior or transverse section of the cylinder is discovered
or exposed. The fixed portions of the plate resist the entrance of the atmo-
spheric air, which can only find admission (if at all) through the small opening F;

page_text: the draft inward is reduced, and but little if any air rushes in. K, K',
are wheels or rollers on which the cylinder is supported; there are two such
wheels at each end of the cylinder. The wheels are keyed on short spindles,
supported in the metal end plates L, L, bolted to the brickwork. One of the front
wheels is in this particular arrangement made smaller than the other to clear
the furnace door, but this is only done when the door is placed as shewn. The
cylinder ends or covers E, T, are flanged, the flanges forming the surfaces that
roll on the wheels K, K¹; the flange of the front end or cover is broader than
the edge of the wheels K, to allow for the expansion of the metal under the
heat evolved. The peripheries of the two front wheels K, K, are smooth, but
those of the back wheels K', K', are grooved, and the flange of the back
end or cover T of the cylinder runs in such groove, whereby the driving
arrangements are kept in proper gear. M is a horizontal driving shaft which
extends the whole length of the back end of the furnace, and communicates
motion to the whole of the cylinders therein. This shaft is supported in
plummer blocks or bearings N, supported on standards O, bolted to the
furnace ends L, L. Rotary motion is communicated to this shaft M by strap
and pulley (not shewn) driven by a steam engine or other ordinary means of
communicating motion. The shaft M carries as many toothed pinions Pas
there are cylinders. On the back end or cover T of each cylinder is fixed a
toothed wheel or rim Q, and each such wheel Q is in gear with a pinion P.
By these means, on rotary motion being communicated to the shaft M, the
said rotary motion will be transmitted to each cylinder. The pinions P are
held on the shaft by forked clutches R, so that any one of the pinions may be
made to run loose on the shaft M, and thus any one cylinder may be stopped
without interrupting the motion of the others.
The cylinders used in re-burning animal charcoal are usually constructed
with double end pieces, namely, an outer front end or cover E, and an inner
or "false" front end S, also an outer back end or cover T, and an inner or
0 "false" back end U. The space left between the pieces E and S and the
space left between the pieces T and U have been hitherto left empty, thereby
causing radiation and loss of heat at those parts. Now, according to my
Invention, I fill up these spaces with fire-bricks, as shewn at V, Figure 4, or
instead of fire-brick I may use other substances, non-conductors of heat, and
5 by these means the waste or radiation of heat is wholly prevented at the end
parts. W is the exit pipe for carrying away the vapours or volatile products
of the distillation or re-burning; this pipe is constructed in the usual manner,
except that it is bent, as shewn, in order to clear the gearing P and Q.
The furnace shewn in the Drawing is so constructed, that instead of each

page_text: cylinder having a separate furnace, as is usual, the arch X is of such span as
to hold two moving or revolving cylinders, both being thus enclosed in and
heated by one and the same furnace; or the span, instead of only subtending
two such cylinders, may be of such radius or curvature as to hold more than two
such cylinders. The furnace is so built, and its bridge Y so situated, that the hot
air, flames, and gaseous products of combustion from the fuel on the fire-bars
of the furnace surround and heat both or all the cylinders fitted in the furnace.
The heat and flames pass away through flues Z to the chimney; or the furnace
may be arranged with a series of arches X, each arch subtending one or more
moving cylinders, a series of fires or sets of fire-bars being arranged in the fur-
nace at a part thereof under the cylinders, and the chambers or portions of the
furnace in which the cylinders are held communicate with one another, so that
each fire may contribute its heat to more than one cylinder. The number of fire-
places may be fewer than that of the cylinders, say, half as many, and instead
of being placed immediately under them, may be arranged one between every
two cylinders, for example, so that a comparatively small number of fires may
heat a large number of cylinders.
Having now described the nature of my said Invention, and in what manner
the same may be performed, I declare that I claim,-
First, the mode of constructing cylinders or retorts, as described, so as to
prevent the necessity of removing the whole end or cover to effect the dis-
charge, by the forming of an opening in the said end or cover only extending
over a limited or restricted portion of such end or cover, whereby the cylinder
or retort can be opened without uncovering the whole end, and without
exposing the contents to a full and continuous rush of air.
Second, the supporting of the cylinder or retort on wheels or rollers on which
it turns, substantially as herein described.
Third, the driving of a revolving or partially revolving cylinder or retort by a
pinion or equivalent gearing into teeth or a toothed wheel, flange, or rim on
one end of the cylinder or retort.
Fourth, the mode of driving a series of cylinders or retorts by a horizontal
shaft lying along the back of the furnace, and carrying pinions or wheels in
gear with teeth or toothed wheels, flanges, or rims on the cylinder or retort
ends.
Fifth, the arrangement of supporting wheels or rollers herein-before
described, in which two are at each end of the cylinder or retort, the rims
of the front pair being narrower than the rim of the front end flange, and the
back pair having grooved rims for the other end flange to work in.
Sixth, the filling of the spaces left between the double end pieces at

page_text: each end of the cylinder with fire-brick or other non-conducting media, as
described.
Seventh, the constructing of the furnace with an arch or chamber of suffi-
cient span or size to receive or contain, and heat more than one moving or
revolving cylinder or retort, so that one furnace may heat more than one such
retort.
Eighth, the constructing of the furnace with a series or set of two or more
arches or chambers so connected, or so communicating with one another, that
the fire of one furnace may transmit its heat to more than one moving or
revolving cylinder or retort.
Ninth, the general arrangement and combination of parts constituting the
improved apparatus for re-burning animal charcoal, herein-before described
and represented in the accompanying Drawings.
In witness whereof, I, the said John Cowan, have hereunto set my hand
and seal, this Twenty-fourth day of December, in the year of our Lord
One thousand eight hundred and sixty-one.
Witness,
M. HENRY,
Patent Agent,
84, Fleet Street, London.
JOHN COWAN. (L.S.)