IMPROVEMENTS IN THE MANUFACTURE OF CARBONS SUITABLE FOR ELECTRICAL PURPOSES AND APPARATUS CONNECTED THEREWITH "
Year: 1882

page_text: LETTERS PATENT to Henry Liepmann and Percy Stratford Looker both of
Leadenhall Street in the City of London for an invention of "IMPROVEMENTS
IN THE MANUFACTURE OF CARBONS SUITABLE FOR ELECTRICAL PURPOSES
AND APPARATUS CONNECTED THEREWITH
"
PROVISIONAL SPECIFICATION left by the said Henry Liepmann and Percy
Stratford Looker at the Office of the Commissioners of Patents on the
3rd March 1882.
HENRY LIEPMANN and PERCY STRATFORD LOOKER both of Leadenball Street in
the City of London "IMPROVEMENTS IN THE MANUFACTURE OF CARBONS SUITABLE
FOR ELECTRICAL PURPOSES AND APPARATUS CONNECTED THEREWITH,"
Our Invention refers to the manufacture of carbons from materials as hereafter
described and their subsequent treatment so as to render them of a high density
and suitable for the production of electrodes and other electric candles and
filaments whether they be rods, tubes, plates, lumps, discs, filaments or otherwise
suitable for electrical and other purposes.
For the purposes of our Invention we employ the material known in commerce
as the "Corosso or ivory nut or vegetable ivory or its clippings turnings or filings
or a material or materials of an analogous nature.
The nut may be used without the shell or the two may be combined, or the shell
may be used alone for filaments; we submit the material to destructive distillation
or we carbonize the material in any other convenient manner either by heat or by
the action of acids so as to leave the carbon produced therefrom in as pure or
partially as pure a state as may be. The nuts or other materials as aforesaid may
be used alone or in combination with other materials such as sugar, resins, oils
and essences or their equivalents, capable of producing a substantially pure
product.
When the "Corosso" or ivory nut or material before referred to has been
subjected to destructive distillation a light and heavy liquid goes over; this

page_text: distillate may be treated separately to get other products or we
can utilize
it to mix with carbon obtained as described to form a pasty mass alone or with
other materials.
In the manufacture of electrodes, for example, according to our Invention a
convenient method of proceeding is as follows. We grind the carbon obtained in
the manner before described to a fine powder and this either alone or in combination
with other carbon such as coke, gas retort carbon, graphite, lamp black, soot or
other such like suitable materials and we may mix it with the oily part of its own
distillate and we knead and work up the whole to a pasty mass with a solution
of sugar, treacle, or molasses, tar, or oils or other hydrocarbons, or we operate by
pressure alone on the carbon or mixture of carbons. When prepared as a paste it
is forced into a mould, say into a steel cylinder when carbon rod electrodes are
required to be produced and by means of plungers the paste is compressed as
tightly as may be considered necessary. The carbon rods after being removed
from the cylinders are dried and then recarbonized by inserting them in iron or
other tubes or otherwise, containing charcoal and then subjected for say half an
hour to the action of the heat of a strong furnace. The carbons are now firm and
coherent but sometimes they are still porous, in which case they are again boiled
in a strong solution of sugar, tar, oil or other hydrocarbon and again subjected to
the operation of carbonization until the requisite uniformity is obtained.
To facilitate the removal of the carbons from the moulds we prefer to inake
them (the moulds) in two parts or halves and we clamp them together in any
convenient way. We make our distilling retort of any suitable material say of
earthenware and we arrange it in such manner that it may be swung or hinged on
gudgeons for example and in a convenient manner for charging and discharging
same with the material to be submitted to the action of the destructive distillation.
In making filaments according to our Invention we form or cut the same to the
shape required from the nut aforesaid or turnings from same or its shell and we
carbonize as before described.
The carbons may if desired be coated with graphite, a thin layer of copper, with
both, or other means suitable for the purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Liepmann and Percy Stratford Looker in the Great Seal
Patent Office on the 2nd September 1882.
HENRY LIEPMANN and PERCY STRATFORD LOOKER both of Leadenhall Street in
the City of London "IMPROVEMENTS IN THE MANUFACTURE OF CARBONS SUITABLE
FOR ELECTRICAL PURPOSES AND APPARATUS CONNECTED THEREWITH
"
This invention refers to the manufacture of a carbon or carbons from materials as
hereafter described and their subsequent treatment so as to render them of a high
density and purity and suitable for electrodes, candles filaments, rods, tubes, plates,
lumps, discs or other forms suitable for electrical purposes.
"
For the purpose of this Invention we employ the material known in commerce
as the "Corosso or ivory nut, or vegetable ivory or its clippings turnings or filings
ie. the waste of the button manufactories which amounts more or loss to 20 per
cent of the ivory nuts employed. The nut may be used without the shell, or the
two may be combined, or the shell may be used alone say for filaments. We
submit the material to destructive distillation or we carbonize the material in any
convenient manner, by preference by heat and by the action of acids such as
hydrochloric or hydrofluoric acid or of caustic alkali and then with hydrochloric
acid and thus leave the carbon produced therefrom in as pure or partially as pure
a state as may be and so as to remove the silica, the iron, the alumina, and other
inorganic substances. The carbon thus made from the nuts, its clippings, turnings
or filings either with or without the shell is used along with a material or
materials for binding the particles of the carbon together such as sugar, resins, oils
essences or such like capable of producing a substantially pure product.
When the "Corosso or ivory nut or material with or without the shell before
referred to has been subjected to destructive distillation a light and heavy liquid go
over, this distillate may be treated separately to get other products
In the manufacture of electrodes according to this invention a convenient
method of proceeding is as follows. We grind the carbon obtained in the manner
before described to a fine powder either before or after the aforesaid purification
process and this either alone or in combination with not more than about 25 per
cent of other carbon such as coke, gas retort carbon, graphite, lamp black, soot or
other such like suitable materials and boil it up by preference in a vacuum with a
solution of sugar, treacle or molasses, tar or oils or other hydrocarbons for the
space of 10 to 50 minutes after which the carbon is strained from the solution
(which may be used again). The object of the addition of this solution is to bind
the parcticles together and to fill the pores.
When thus prepared it is forced into a mould say into an iron or steel cylinder
and by means of a hydraulic plunger press operating at a pressure of say 100 to
200 tons per square inch the mass is compressed as much as is considered
necessary.
To facilitate the removal of the carbons from the moulds we prefer to make the
latter in two parts or halves. Figure 1 of the accompanying drawings is a vertical
cross section of such a mould and Figure 2 a plan of lower half of same. A is the
lower half which has removable dovetail ends A¹; B¹ is the upper half forming
part of the plunger or ram of a bydraulic press.
The material having been put into the mould say about to the dotted line a, a
Figure 1 the plunger with die B' is then brought down and the contents compressed
to the cylindrical form. Figure 3 shows an arrangement of inould for making
three carbons at a time, but the mould can be made for any desired number of

page_text: carbons, the form of the latter whether rods, plates (such as for batteries for
instance) discs, incandescent burners or otherwise determines the form and con-
struction of the mould. After compression the ends A' are removed and the
carbon or carbons can then be easily pushed out. The die B' may be fitted to the
ram B in the manner shown.
The carbon rods after being removed from the cylindrical or other moulds are
dried at a temperature gradually rising from 80 to about 140° centigrade and are
then soaked or boiled by preference in a vacuum in the aforesaid sugary or other
solution which together with the remaining solution originally in the material
requires to be carbonized. This is done by inserting them in iron or other tubes
or vessels the spaces being filled up with any suitable substance say charcoal to
exclude air as much as possible, then subjected to say 30 to 60 hours more or less
as required to the action of a heat sufficient to convert the sugar or other filling
and binding bodies into carbon with as little volatilization that is as low a
temperature as possible, for this purpose we prefer to carbonize in a vacuum or
partial vacuum. The carbons should now be firm and coherent; if still porous they
are again soaked and boiled in a strong solution of sugar, tar, oil or other bydro-
carbon by preference in a vacuum and again subjected to the operation of
recarbonization by preference in a vacuum until the requisite uniformity is
obtained.
+
We may make our distilling retort of any suitable material say of fireclay,
earthenware and the like and arrange it in any suitable manner but prefer that it
may be swung or hinged on gudgeons for example and in a convenient manner for
charging and discharging same with the material to be submitted to the action of
the destructive distillation.
The carbons if desired are coated with graphite or with a thin layer of copper or
nickel or with graphite and copper or nickel. The copper or nickel coating may
be produced by electrolysis or otherwise.
"
And having thus in the foregoing described not only the general mode in which
"Corosso nut waste is rendered useful to the manufacture of pure and dense
carbon electrodes but having also described a superior process of manufacturing
carbon electrodes from such and other suitable carbonizable materials namely by
excluding the air from the material under treatment during certain stages of the
process and thus saving much time and also producing a still denser material or
article we declare that we claim :-
First: The application of carbonized "Corosso " nut waste to the manufacture
of carbon electrodes substantially as and for the purpose set forth.
Second: The combined process for manufacturing carbon electrodes consisting in
carbonizing or distilling, pulverizing, purifying, treating with binding and filling
material in a vacuum, moulding under heavy pressure, drying treating with filling
material again and carbonizing in a vacuum so as to expedite the process and
produce a denser article all substantially as described.
In witness whereof I the said Henry Liepmann for myself and on behalf of
the said Percy Stratford Looker have hereunto set my hand and seal this
First day of September in the year of Our Lord One thousand eight
hundred and eighty two:-
HENRY LIEPMANN. Ph.D. (L.S.)