IMPROVEMENTS IN THE MANUFACTURE OF ELECTRODES FOR THE PRODUCTION OF ELECTRIC LIGHT
Year: 1879

page_text: LETTERS PATENT to William Morgan-Brown, of the Firm of Brandon and
Morgan-Brown, Engineers and Patent Agents, of 38, Southampton Buildings,
London, and 1, Rue Laffitte, Paris, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF ELECTRODES FOR THE PRODUCTION OF ELECTRIC
LIGHT."
A communication from abroad by Paul Albert Porlier, Chemist, of
1. Rue Laffitte. Paris.
Sealed the 13th February 1880, and dated the 20th August 1879.
PROVISIONAL SPECIFICATION left by the said William Morgan-Brown at
the Office of the Commissioners of Patents on the 20th August 1879.
WILLIAM MORGAN-BROWN, of the Firm of Brandon and Morgan-Brown, Engineers
and Patent Agents, of 38, Southampton Buildings, London, and 1, Rue Laffitte,
Paris. "IMPROVEMENTS IN THE MANUFACTURE OF ELECTRODES FOR THE PRODUC-
TION OF ELECTRIC LIGHT." [A communication from abroad by Paul Albert Porlier,
Chemist, of 1, Rue Laffitte, Paris].
This Invention consists in replacing the usual carbon electrodes and others by
electrodes, which are good conductors, made substantially with an external metal
pipe such as steel, the rate of combustion of which is diminished by a substance
charged within the tube and apt to form with the metal a combination which is a.
bad conductor of electricity, which combined matter is constantly reproduced by
the electric current as fast as it is consumed by the said current.
This outer tube is formed of any appropriate metal, preferably steel, either by
rolling sheet metal with the edges simply butted together or united by brazing,
soldering, or otherwise, or by means of drawn tubing; within the same I charge
and compress a powder or paste, composed of one or more oxides, capable of acting
the part of a base with reference to the metallic oxide produced by the combustion
of the metallic tube, and to form with the same a slag or dross of such a consistence
that it will not run.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Morgan-Brown in the Great Seal Patent Office on the 14th
February 1880.
WILLIAM MORGAN-BROWN, of the Firm of Brandon and Morgan-Brown, Engineers
and Patent Agents, of 38, Southampton Buildings, London, and 1, Rue Laffitte,
Paris. "IMPROVEMENTS IN THE MANUFACTURE OF ELECTRODES FOR THE PRODUC-
TION OF ELECTRIC: LIGHT." A communication from abroad by Paul Albert Porlier,
Chemist, of 1, Rue Laffitte, Paris.
This Invention consists in replacing the carbon electrodes which have heretofore
generally been employed for the production of electric light, as well as other kinds
of electrodes proposed by different inventors, and even those with a metallic core
by electrodes, which are good conductors of electricity, and consist substantially in
an external metallic tube, the combustion of which is slackened by a substance
charged within the tube and which is capable of forming with the metal of the
tube a combination, which is a bad conductor of electricity, and which is constantly
reproduced under the influence of the electric current at the same ratio at which it
is consumed by that same current.
In carrying out the Invention a metallic tube, preferably of iron or steel, is used
which may be formed of sheet metal rolled, with the edges simply butted together
or united by brazing, or soldering, or drawn tubing may be used instead. Within
this tube is charged, and strongly compressed, a paste formed of oxide of magnesia
slightly moistened with water. Instead of oxide of magnesia may be used also
dolomite, freed from silica, lime, alumina, or carbonates of magnesia, of lime, and
even of baryta and of strontian. It must be said that the lime, the baryta, and
the strontain, color the light, a circumstance which according to the case may be
an advantage or a disadvantage. I can also use the different substances named by
mixing two or more of them together. These substances act as bases with reference
to the metallic oxide formed by the combustion of the exterior tube, and under the
influence of the electric current they form with this metallic oxide a slag or dross
in fusion, but still of sufficient consistency to prevent it from running.
In the annexed Drawing Figure 1 is a cross section through one of the new
electrodes; Figures 2 and 3 show in vertical section two electrodes arranged in
line with each other, and burning by means of any suitable regulator. These
Drawings represent, in full size, electrodes in which the exterior tube is made of
iron and is fitted with oxide of magnesia.
The dimensions of the electrodes must evidently vary with the quantity and the
intensity of the electric currents. I have found that the electrodes represented in
the Drawing give excellent results with a two-horse power machine constructed
after Gramme's system, and emitting constant currents. In this case the consump-
tion per hour amounts to from 3 to 5 eights of an inch, with alternate currents
this amount will even be somewhat less.
The length of the electrodes is equally undetermined. I may say, however, that
in consequence of the insignificant consumption compared with the electrodes
hitherto used, tubes of 8 inches length will be quite sufficient for 24 hours'
illumination.
In the manufacture of these electrodes special care should be taken with regard
to the selection of the raw material, as also with regard to the preparation and the
respective weights of such material. It is to be remarked that in order to obtain
the greatest amount of light, together with the smallest possible consumption, the
weight of the metal tube with reference to that of the oxides or carbonates
compressed in that tube must be in exact proportion corresponding to the chemical
equivalents of the materials of which the electrode consists. On the other side, the
oxides or carbonates should be exempt from silicum, and should be equally

page_text: compressed in their entire mass, so that the respective weights of the materials are
distributed in the proportions indicated along the entire length of the electrodes.
The great conductibility of these electrodes results from the fact that the case is
formed of a well conducting metal. Thereby the resistance which the electric
current finds on its passage is greatly reduced. The electrodes, as well as the
regulators, become heated but very little, and I can arrange a great number of
lights in one circuit.
These new electrodes emit sparks when they are lighted for the first time and
before the dross is formed. I avoid this difficulty by fixing on one end of each
electrode a small quantity of a paste formed of pulverized retort-carbon which is
agglommerated by means of a little gum, or instead of this method I can simply fix
a small piece of retort carbon in the end of the tube. If desired I can light the
electrodes before delivering them for use, so that they carry the dross already
formed on them and that they can be used at once like ordinary carbon electrodes.
The consumption of these electrodes is very insignificant, and results simply from
the mechanical transport of particles caused by the electric current and from the
volatilisation of a small quantity of oxide. In consequence of the passage of the
electric current the metal forming the exterior tube melts, and by becoming oxidized
acts upon the oxides or carbonates enclosed in the interior of the tube and forms
an incandescent drop of molten dross. A part of the metal contained in this dross
burns and imparts to the voltaic arc a very high intensity as well as a great
steadiness that has been unattainable with the electrodes heretofore employed.
Having now described and particularly set forth the nature of the said Invention,
and the manner of carrying the same into effect, I would have it understood that
what I claim is,―
Electrodes or pencils used for the production of electric light, consisting of a
metallic tube filled with one of the above named oxides or carbonates, or with a
mixture of two or more of the said substances, so that in consequence of the passage
of the electric current the metal of the tube forms, with the material enclosed
within the tube, a chemical combination in the shape of a molten dross, which,
however, is sufficiently dense so as not to run; the voltaic arc being then formed
between these two drops of dross, as above described, without limiting myself with
regard to the shape. or dimensions of these electrodes which naturally must vary
with the intensity and quantity of the electric currents as well as with the different
systems of production of electric light.
In witness whereof, I, the said William Morgan-Brown, have hereunto set my
hand and seal, this Fourteenth day of February, in the year of our Lord
One thousand eight hundred and eighty.
.
WILLIAM MORGAN-BROWN. (L.S.)