Improvements in Carbons or Electrodes for Arc or other Electric Lamps.
Year: 1891

page_text: Date of Application, 5th June, 1891
Complete Specification Left, 5th Mar., 1892-Accepted, 23rd Apr., 1892
PROVISIONAL SPECIFICATION.
Improvements in Carbons or Electrodes for Arc or other Electric
Lamps.
I, JAMES EGLINTON ANDERSON GWYNNE, of Victoria Embankment in the
County of Middlesex, Civil Engineer, do hereby declare the nature of this invention
to be as follows :-
My invention relates to improvements in the construction of carbon or other
electrodes for arc electric lamps, and has for its objects the production of a proper
crater or a concave recess upon the positive electrode or carbon, and a corresponding
point or cone upon the negative electrode, which is adapted to said crater or concave
recess, and also to improve the conductivity of said electrodes by the insertion of
wires or by admixture, induration or assimilation of other substances or materials
for affecting the color of the radiation of the are without the employment of globes,
shades, or the like of different tints for that purpose.
The improved construction according to my said invention may be carried out
by a mechanical process after the carbon electrodes have been formed by com-
pression as hitherto, or I may adopt certain appliances to a mould or the like
during formation by compression.
The essential feature of my said invention consists primarily in forming an initial
crater and corresponding cone upon the positive and negative electrodes of an arc
electric lamp or other electric lamp of a similar kind, so that an arc of the
proper shape, luminosity and focal position may be established directly the current
of electricity is applied to said lamp without the uncertainty, waste of time, power
and carbon or other material resulting from the use of electrodes as hitherto made
and used.
The method of and means for forming an initial crater and cone as herein
described enables me to produce any required degree of divergence of the rays of
light which may be sustained throughout the period of consumption of the
electrodes, if these are homogeneous in structure and are subject to a regular feed
free from external disturbance.
In carrying my invention into practice I may, hy modifying the construction of
the moulds in which such electrodes are formed by compression produce the required
shape or conformation of both carbons. It is however necessary to provide a
moveable block or end to the mould to enable the core of the crater to be with-
drawn before the mould is parted for extraction; and I may either use a separate
block which is controlled by a spring or equivalent and manipulated by a trigger or
button, or a removeable core which may be withdrawn from the mould before the
formed electrode is extracted. In the case of the negative electrodes, the modified
shape of the mould suffices for moulding and extraction without using any special
device for this purpose.
may subject a positive electrode of the usual form to mechanical processes of
grinding and boring, so that a conical crater or concave recess is formed in the
point, said crater or concavity being concentric with the circumference of said
carbon, or if required may be at a suitable angle therewith to afford a certain
degree of divergence of the rays of light.
The negative carbon may also be formed mechanically by grinding or an
equivalent method of pointing or forming a conical end corresponding to the crater
or concavity of the positive carbon aforesaid.
The above mentioned devices are also applicable to solid carbons or other
electrodes and to those containing or made to contain one or more cores, hollow, or
therwise.

page_text: I may insert metallic wires, or metallic cores in the substance of the electrodes
for the purpose of increasing the conductivity thereof, or I may add to the plastic
mass during formation any suitable metallic bodies or salts and thoroughly
incorporate these, for the purpose of increasing the conductivity thereof, and also
varying the tint or color of the light rays from the arc instead of producing this
effect by colored mediums as heretofore.
Dated this 5th day of June 1891.
FREDK. WALKER,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.
COMPLETE
SPECIFICATION.
Improvements in Carbons or Electrodes for Arc or other Electric
Lamps.
I, JAMES EGLINTON ANDERSON GWYNNE, of Victoria Embankment, in the
County of London, Civil Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
My invention relates to improvements in the construction of carbon or other
electrodes for use in are electric lamps, and has for its objects the production of a
proper crater or a concave recess within the point of the positive electrode or
carbon, and a corresponding point or cone upon the negative carbon or electrode,
the two shapes thus forming a practically perfect pair of electrodes for starting and
maintaining an electric arc, and also to improve the conductivity of said electrodes
by the insertion of wires into the carbon or by admixture, induration, or assimilation
of other substances or materials.
In carrying my invention into effect, I may shape the ends of the positive and
negative carbons to form an initial crater and point respectively by any suitable
mechanical process, such for instance as a revolving cutter, or said initial crater and
point may be formed in the process of moulding or compressing, and I may adopt
any suitable appliances therefor.
One of the essential features of my said invention thus consists in forming an
initial crater and corresponding cone on the positive and negative carbons or
electrodes respectively of an arc or other electric lamp, so that an arc of proper
shape, luminosity, and focal position may be established directly the current of
electricity is applied to said lamp, obviating the uncertainty, waste of time and of
electrical energy and carbon or other material as obtains in the case of electrodes as
at present made and used. Further, by thus forming an initial crater and cone !
am enabled to produce any required degree of divergence of the rays of light which
may be sustained throughout the period of burning or consumption of the said
electrodes, provided that these are homogeneous in structure or consistance, and are
subjected to a regular and uniform feed or travel free from external disturbance.
In carrying my invention into practice, I may, by modifying the construction of
the dies or moulds in which such electrodes are formed, cause the ends to assume
the required shape as hereinbefore referred to. In the case of a mould it is necessary
to provide a moveable block or end to said mould to enable the core of the crater
to be withdrawn before the mould is parted for extraction, and I may either use a
separate block which is controlled by a spring or equivalent, and manipulated by a
trigger or button, or a moveable core which may be withdrawn from the mould
before the formed clectrode is extracted. In the case of the negative electrodes,
the modified shape of the mould suffices for moulding and extraction without using
any special device for this purpose.
.
I may subject a positive electrode of the usual form to mechanical processes of
grinding or boring, so that a conical crater or concave recess is formed in the end,
said crater or concavity being concentric with the circumference of the carbon or
electrode, or if necessary it may be arranged angularly therewith to afford a certain

page_text: degree of divergence of the rays of light. The negative carbon may also be formed
mechanically by grinding or any mechanical shaping process for pointing or forming
a conical end corresponding to the crater or concavity of the positive carbon
aforesaid.
Having thus shaped or formed the electrodes so as to present an initial crater
and cone as hereinbefore described, for the purpose of starting a steady and uniform
arc, I preferably, in order to maintain the regular and uniform preservation of said
shape necessary to keep up an unwavering light, form one or both electrodes with
an hollow core, or hollow cores, filled with any suitable substances, preferably in a
pulverized state, which are vaporised at a slightly lower temperature than the
substance of the electrode surrounding said core or cores, such for example as a
mixture of carbon and silica. When the arc is once established, the free
combustion and transference of the substance of the core or cores of the positive
electrode, reduces resistance and increases the luminosity of the arc, the hollow or
concavity of the crater thus being preserved intact until the electrode is entirely
consumed. Further, a distinct advantage is in that the concentration of such a
vaporisable medium within the crater, and directly opposite to the cone of the
negative electrode, causes the arc to be maintained centrally and give a steady
light without noise, and the diverting or travelling of the line of said arc, and
consequent distortion of the crater and cone is obviated.
I may in certain cases insert metallic wires, or other cores of conducting material
in the substance of the electrodes for the purposes of increasing the conductivity
thereof, or I may add to the plastic mass during formation any suitable metallic
bodies or salts, and thoroughly incorporate these with the plastic material of which
said electrodes are made, for the purpose of reducing the resistance of the circuit
and also for varying the tint or color of the rays of light emanating from the arc.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is ;-
First. The formation and application of an initial crater upon a positive
electrode, and a point or cone upon a negative electrode for use in an electric lamp,
substantially as and for the purposes herein described and set forth.
Second. In carbons or electrodes for arc or other electric lamps, the combination
of a core or cores of silica or mixture thereof with an initial crater upon the
positive and cone upon the negative electrodes respectively.
Dated this 4th day of March 1892.
FREDK. WALKER,
11, Furnival Street, Holborn, London, E.C., Agent for the Applicant.