IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS.
Year: 1876

page_text: LETTERS PATENT to Richard Werdermann, of Princes Street, in the County of
Surrey, Civil Engineer, for the Invention of "IMPROVEMENTS IN ELECTRIC
LIGHTING APPARATUS.'
"
Sealed the Sth June 1877, and dated the 12th December 1876.
PROVISIONAL SPECIFICATION left by the said Richard Werdermann at the
Office of the Commissioners of Patents on the 12th December 1876.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS."
My said Invention relates to improvements in electric lamps, carbon electrodes
for the same, and in other apparatus for the production of electric light.
The carbon electrodes or carbons to be used in connection with the said electric
Jamps are coated with any suitable material, which will protect the same from
contact with air, and which is volatile when exposed to the intense heat of the
voltaic arc.
I use by preference calcined magnesia, sulphate of magnesia, borax,
sulphate of lime, and other substances or bodies, which in burning emit a great
amount of light.
The principal advantages of such coating of the carbons are the following,
namely:-
First. The flame produced by the burning of the carbons, which diminishes con-
siderably the intensity of the light by covering the same, is reduced to a minimum.
Second. By excluding the air from contact with the carbons the heating of the
electrodes is partly pevented.
Third. The coating material which is volatilised as the carbons are consumed
produces a greater amount of light and reduces the resistance of the circuit.
My Invention relates partly to an electric lamp not designed to be used in con-
nection with reflectors or holophotes.
The carbon electrodes are supported in the required proximity to each other, and
are automatically adjusted in proportion to their combustion in the following
manner, that is to say:-The carbon pieces are curved so as to forin portions of a
circle; one of these pieces is secured in a fixed arm or bar, and the other is secured
in an arm or beam pivoted to the said fixed bar. This pivoted arm is provided with

page_text: a balance weight, preferably containing sand or liquid, which escapes and diminishes
the weight, or with an arrangement of clockwork which regulates the action of the
said arin or beam, and always keeps the carbon points the proper distance apart.
Or I may employ electro-maguets or other suitable means for automatically
regulating the distance of the carbon points from each other during their com-
bustion.
Another part of my Invention relates to carbon electrodes to be used without any
lamps or regulator, as follows, that is to say :-Two concentric hollow cylinders of
carbon are insulated from each other by any suitable insulating material, which,
when exposed to the heat of the voltaic arc, will be volatilised. The inner side of
the inside carbon, and the outer side of the outside carbon electrode are equally
covered with the insulating material. A powerful current of air will pass through
the hollow space as through a chimney, and will accelerate the combustion of the
carbon and of the insulating material. The said inner cylinder instead of being
hollow may be solid. The outer cylinder is about one inch shorter or longer than
the inner one; both are fixed by screws in a holder consisting of two insulated
metal cylinders which are connected with the two poles of the electric current
generator.
Instead of using carbon cylinders, rods of carbon of square or oblong section may
be placed parallel, as set forth in the Specification of my former Letters Patent, dated
April 24th, A.1). 1874, No. 1438. It is advantageous to make the negative electrode
only half as thick as the positive one, a very uniform consumption of the carbon
being thereby obtained.
When the light is not required to illuminate in all directions, but when it is
desirable to obtain a very powerful point of light, I place a rod of carbon in front
of a plate of carbon parallel with and insulated from the same by mica or other
suitable material.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Richard Werdermann in the Great Seal Patent Office on the
12th June 1877.
RICHARD WERDERMANN, of Princes Street, in the County of Surrey, Civil
Engineer. "IMPROVEMENTS IN ELECTRIC LIGHTING APPARATUS."
My said Invention relates to improvements in electric lamps, and in carbon
electrodes for the same, and in other apparatus for the production of electric light.
DESCRIPTION OF THE DRAWING.
Figure 1 is a longitudinal section, and Figure 2 is an cnd view of a carbon
electrode covered or coated according to my Invention as herein-after described.
Figure 3 is a side elevation of an electric lamp constructed according to my
Invention.
Figure 4 is a longitudinal section, and Figure 5 a transverse section illustrating
my improvements in carbon electrodes; Figure 5 is a transverse section shewing a
modification of the same.
Figures 6, 7, 8, 9, are similar views illustrating other modifications of this part of
my Invention.
Figure 10 shows in transverse section various forms of my improved carbons or
carbon electrodes.
Figure 11 is a perspective view illustrating a further modification in the con-
struction of my carbon electrodes.
Like letters indicate the same parts throughout the Drawing.
The improved carbon electrodes or carbons, a, to be used in connection with the

page_text: said electric lamps are coated as shewn at a¹, Figures 1 and 2, with any suitable
material, which will protect the same from contact with air, and which is volatile
when exposed to the intense heat of the voltaic arc. I use by preference, either
separately or two or more of them in combination, the following materials, namely,
calcined magnesia, sulphate of magnesia, borax, boracic acid, sulphate of lime, fire-
clay, glass, alumina, or other substances or bodies, which in burning emit a great
amount of light.
The principal advantages of this coating of the carbons are the following,
namely:
:-
1. The flame ordinarily produced by the burning of the carbons, and which
diminishes considerably the intensity of the light by covering or enveloping the same
is reduced to a minimum.
2. By excluding the air from contact with the carbons the heating of the electrodes
is partly prevented.
3. The coating material which is volatilized as the carbons are consumed produces
a greater amount of light, and reduces the resistance of the circuit.
The electric lamps constructed according to my Invention are not designed to be
used in connection with reflectors or holophotes. In these lamps the carbon
electrodes or carbons are supported in the required proximity to cach other, and are
automatically adjusted in proportion to their combustion in the following manner,
that is to say The carbon pieces a are so curved, as shown in Figure 3, as to form
portions of a circle. One of these pieces is secured in a fixed support b, and the
other picce is secured in an arm or beam c pivotted to the said fixed support. This
pivotted arm may be provided with a balance weight, preferably containing sand or
liquid which escapes and diminishes the weight. But I prefer to provide the said
apparatus with an arrangement of clockwork at d, which regulates the action of the
arm or beam c, and always keeps the carbon points a the proper distance apart. Or
may employ electro-magnets, or other suitable means for automatically regulating
the distance of the carbon points from each other during their combustion.
My improved carbon clectrodes to be used without any lamp or regulator are
constructed as follows, that is to say-In Figures 4 and 5 I have shewn two con-
centric hollow carbon cylinders a, a², insulated from each other by any suitable
insulating material, as shewn at f, and which when exposed to the heat of the
voltaic are will be volatilized. The inner side of the inside carbon cylinder a, and
the outer side of the outside carbon cylinder a², may be equally covered with the
insulating inaterial. A powerful current of air will pass through the hollow space g
as through a chimney, and will accelerate the combustion of the carbon and of the
insulating material. The said inner cylinder instead of being hollow may be solid,
as shewn in Figure 5. The outer cylinder of these electrodes is about one inch
shorter than the inner one, as shewn at Figure a³. Both cylinders are fixed
by a screw in a holder i; I prefer to use a holder consisting of two insulated
metal cylinders j, k, which are connected with the two poles of the electric current
generator, as shewn in Figure 4.
Instead of using carbon cylinders, rods of carbon of square, oblong, or other
suitable section may be placed side by side, parallel with each other, as set forth
in the Specification of my former Letters Patent, dated 24th April, A.D. 1874,
No. 1438.
Figures 6 and 7 shew one of my improved electrodes formed of flat bars or rods a,
of carbon insulated at f, and suspended in a holder i.
In Figures 8 and 9 I have shewn one of the said electrodes consisting of flat rods a
secured together by clips 7.
Various sectional forms of my improved carbon rods are shewn at e, Figure 10.
Where a continuous electric current is used it is advantageous to make the
negative electrode only half as thick as the positive one, a very uniform con-
sunption of the carbon being thereby obtained.
When the light is not required to illuminate in all directions, but when it is
desirable to obtain a very powerful point of light, I place a rod a of carbon in front

page_text: of a plate of carbon at, parallel with and insulated from the said plate by mica or
other suitable material, as shewn at m, Figure 11.
Having thus fully described my said Invention, and the manner of performing
the same, I wish it understood that I claim for the purposes above specified,―
First. The coating of carbons or carbon electrodes with metallic oxides or salts
for the purposes specified.
Second. The coating of carbons or carbon electrodes with borax or with boracic
acid mixed with or in which are dissolved metallic oxides, salts, or other suitable
material, as above set forth.
Third. In an electric light or lamp the curved carbons arranged in the manner ]
above specified.
Fourth. In the construction of carbons or carbon clectrodes the carbon cylinders
placed one within the other, or side by side and parallel with each other, as above
set forth.
Fifth. The modification of my Invention in which I place the carbon or carbons
in front of a carbon plate, as above set forth.
Sixth. The employment of mica as an insulating material for carbons used for the
production of electric light, as above set forth.
In witness whereof, I, the said Richard Werdermann, have hereunto set my
hand and seal, this Twelfth day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
RICHARD WERDERMA NAT Gol