IMPROVEMENTS IN THE MANUFACTURE OF COKE
Year: 1856

page_text: PROVISIONAL SPECIFICATION left by Antoine Perpigna at the Office
of the Commissioners of Patents, with his Petition, on the 11th April
1856. A communication.
I, ANTOINE PERPIGNA, Advocate, of Paris, in the Empire of France, do
hereby declare the nature of the said Invention for IMPROVEMENTS IN THE
MANUFACTURE OF COKE, to be as follows:-
The object of this Invention is to produce coke possessing the qualities of
hardness and compactness, which qualities are desirable in coke employed in
locomotive engines or in smelting metals. To attain this end, coals of different
kinds are combined in varying proportions, and carbonized together, in place
of employing bituminous coal alone, as is ordinarily practised. For example,
by combining in suitable proportions bituminous small coal and steain coal
(houille à. vapeur dite demi sèche), and carbonizing the same, coke of greater
density may be economically obtained; or, when bituminous coal is combined
with anthracite, a still superior quality will result.
It is well known that pure anthracite gives out the most heat during com-
bustion, but that it possesses the disadvantage of not burning in the open air;
this disadvantage disappears entirely after the conversion of the coal into coke,
and the result is a compact fuel, giving out greater heat than any other kind
of coke capable of burning in the open air, and possessing the required degrees
of density and homogeneity. During the process of carbonization the bitu-
minous coal is melted and becomes puffed out into a cellular mass, the cells of

page_text: which are filled up by the dry coal, thus causing them to bind together and
produce coke of considerable density.
Coke made with a mixture of two-thirds bituminous coal and one-third dry
coal differs but little in appearance from that made from bituminous coal
alone, but it is more dense, heavier, and its texture less cellular.
Coke made from two-thirds bituminous coal and one-third anthracite has
an appearance like polished silver, and is of still greater density.
Although ordinary coke ovens may be employed for the above purpose, it is
preferred to use circular ovens, the foundation of which is dug in the earth,
and the outer wall built up in ordinary brickwork, and lined with fire brick.
The bed of the oven is composed of a layer of sand, covered with fire brick,
and the dome also consists of fire brick.
For the purpose of preventing the injurious effects arising from expansion,
which is most violent at the spring of the arch above the oven doors, the
outer wall is bound round with a circular band of iron rods (say twenty in
number), fastened together by screw bolts. I provide the oven with an
opening or regulator for the admission of cold air, in order to regulate its
working, which opening is closed by a door of fire brick and iron. The
oven is heated to the temperature required for igniting the charge of mixed
coal, which is then introduced, the doors are closed, and the charge allowed
to ignite; the damper communicating with the flue is then opened; openings
or dampers in the doors are also opened to permit of the access of suffi-
cient air to ignite the escaping gases. When the outer crust or surface
of the coal begins to assume a red heat, and flame escapes through fissures
therein, which may be ascertained by looking through the openings in the
doors, these latter are closed and the regulator opened. The oven is then left
in operation for twelve hours, after which the regulator is closed, and the oven
again left in operation for thirty-six hours. The regulator is then slightly
opened until the escaping products consist merely of gases without flame; the
regulator must then be quite opened, and when these gases have disappeared
the damper is closed and the regulator left open, and after the expiration of
twelve hours the coke may be drawn out by means of suitable apparatus.