AN IMPROVED MODE OF MANUFACTURING CARBONS FOR ELECTRICAL PURPOSES
Year: 1878

page_text: 26
LETTERS PATENT to Matthew Gray, of Cannon Street, in the City of London,
Engineer, for the Invention of AN IMPROVED MODE OF MANUFACTURING
CARBONS FOR ELECTRICAL PURPOSES."
PROVISIONAL SPECIFICATION left by the said Matthew Gray at the Office
of the Commissioners of Patents on the 9th November 1878.
MATTHEW GRAY, of Cannon Street, in the City of London, Engineer.
IMPROVED MODE OF MANUFACTURING CARBONS FOR ELECTRICAL PURPOSES."
" AN
The chief object of this Invention is to produce in an economical manner carbons
suitable for electric lights, the density of which carbon is required to be uniform,
and the length such as will enable the light to be maintained for many hours
without the necessity for renewing the carbons. For this purpose I take carbon
prepared in any approved manner and reduce it to powder. This powder I wash
in alkaline or acid solutions in order to remove any impurities therefrom. The
powdered carbon is then mixed with sugar, molasses, or other suitable adhesive sub-
stance which will liquefy with heat, the consistency required for the compound being
something like that of puddled clay. When in this state the mixture is fit for
moulding into such shapes as the carbons are intended to assume.
For the purpose
of moulding this carbon mixture I use a moulding press similar to that employed in
forining lead pipes or drain pipes, and by heating the cylinder in which the material
to be moulded is placed I maintain the carbon mixture in or reduce it to a plastic
state.

page_text: By the pressure of a plunger or of a propelling screw I condense the carbon
mixture in the cylinder of the press and cause it to exude therefrom through dies
fitted in the moulding press in cylindrical or other forms; I am thus enabled to
obtain carbons of any desired length greatly in excess of those at present produced.
These carbons as they are delivered from the press it will be desirable to submit to
a high heat in order to expel therefrom any moisture they may contain.
The carbons used for the electric light will be made preferably of a cylindrical
form, but for electrical batteries the carbons will take other forms, such as those at
present employed for the purpose, the object being in general to obtain a large
surface proportionate to the amount of material used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Matthew Gray in the Great Seal Patent Office on the 9th
May 1879.
MATTHEW GRAY, of Cannon Street, in the City of London, Engineer. " AN
IMPROVED MODE OF MANUFACTURING CARBONS FOR ELECTRICAL PURPOSES."
The chief object of this Invention is to produce in an economical manner carbons
suitable for electric lamps, the density of which carbons is required to be uniform,
and the length such as will enable the light to be maintained for many hours without
the necessity for renewing the carbons.
For this purpose I take carbon prepared in any approved manner and reduce it
to powder; this powder I wash in alkaline or acid solutions in order to remove any
impurities therefrom. The powdered carbon is then mixed with sugar, molasses, or
other suitable adhesive substance which will liquefy with heat, the consistency
required for the compound being something like that of puddled clay.
When in this state the mixture is fit for moulding into such shapes as the carbons
are intended to assume. For the purpose of moulding this carbon mixture I use a
moulding press similar to that employed in forming lead pipes or drain pipes, and
by heating the cylinder in which the material to be moulded is placed I maintain
the carbon mixture in or reduce it to a plastic state.
By the pressure of a plunger or of a propelling screw I condense the carbon
mixture in the cylinder of the press and cause it to exude therefrom through dies
fitted in the moulding press in cylindrical or other forms. I am thus enabled to
obtain carbons of any required sectional form, and of any desired lengths, which
may be greatly in excess of those at present produced.
These carbons as they are delivered from the press I submit to a high temperature
in a furnace for the purpose of carbonizing the saccharine matter of the carbon
mixture. I then, in order to fill up the pores in the carbons, immerse thein in
boiling sugar or molasses and subject them to a reheating for the purpose of carboni-
zing the saccharine matter contained therein.
The carbons used for the electric light will be made preferably of a cylindrical
form, but for electrical batteries the carbons will take other forms, such as those at
present employed for such purpose, the object being in general to obtain a large
surface proportionate to the amount of material used. By the above described mode
of manufacturing carbon cylinders and plates I am enabled not merely to ensure an
uniform density of the material, and to obtain the same in any desired lengths, but
I also effect a material economy in the cost of manufacture.
Having now set forth the nature of my Invention of "An Improved Mode of
Manufacturing Carbons for Electrical Purposes," and explained the manner of
carrying the same into effect, I wish it to be understood that under the above in
part recited Letters Patent, I claim,―
The moulding of carbons for electrical purposes, in the manner and for the pur-
poses above set forth.
In witness whereof, I, the said Matthew Gray, have hereunto set my hand
and seal, the Ninth day of May, in the year of our Lord One thousand
eight hundred and seventy nine.
MATTHEW GRAY. (L.S).