Improvements in Electric Arc Lighting.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Arc Lighting.
I, LLEWELLYN SAUNDERSON, Esquire J.P. of 10 De Vesci Terrace Kingstown,
County of Dublin, Ireland, 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:-
The object of my Invention is to produce an intense yellowish-white light of great
illuminating power in foggy as well as in clear weather between the electrodes of the
arc lamp by adding to the arc flame light-rays of long wave length, in which the
rays
arc light as usually exhibited between carbon electrodes is deficient. I attain this end
by supplying to the arc a minute quantity of highly-heated carbonaceous vapor.
My invention is illustrated by the annexed drawings.
Figure 1 is an elevation, partly in section, of the lower carbon for an arc lamp.
Figure 2 is also an elevation, partly in section, of a lower carbon, and shows a
modification. Figuro 3 is an elevation, partly in section of an upper carbon, and
shows another modification.
I employ, as shown in Figure 1, a small box a with a hollow or tubular carbon
electrode b inserted securely into it through the cover. This box is filled with vaseline
or some other semi-liquid hydrocarbon. The electrode has a tightly packed plug e
inserted at the end farthest away from the arc. This plug extends two or three inches
up the electrode, and is composed of fibrous material such as cotton, sponge &c. One
end of this fibrous plug is in contact with the vaseline or some other semi-liquid
hydrocarbon in the box a. This plug will at one end be continually kept slightly
moistened with the bydrocarbon, and the remainder of the plug acts as a retarder to
the vapor arising from this moistened end produced by the heat of the carbon electrode.
A minute quantity only of hydrocarbon vapor is by these means formed at any one
time, in consequence of the difficulty the liquid meets with in entering the electrode,
and in consequence of the fibrous plug opposing a resistance to the passage of
the vapor. This small quantity of vapor in its passage up the electrode, before it
enters the arc, becomes highly heated for the electrode gradually increases in
temperature as it approaches the arc, and is enabled to raise this minute quantity of
vapor to a very intense heat before it enters into the arc. In this way, without
cooling the carbon in the neighborhood of the arc, a small quantity of hydrocarbon
vapor is applied at intense heat, which is perfectly consumed at the arc, adding to the
light those rays of long wave length which would be otherwise deficient, producing an
intense yellowish-white light. These electrodes are capable of being used in an
electric-arc lamp of ordinary construction. The upper electrode may be a solid carbon,
or it may be an electrode such as is shown by Figure 3. 1, however consider it
unnecessary that hydrocarbon vapor should be supplied simultaneously through both
electrodes.
In Figure 2 I employ a bent tube d, preferably of metal closely packed with
a fibrous substance. This is inserted into the end of the electrode 6 farthest awar

page_text: from the arc. The fibrous plug c is allowed to continue a short way up the hollow
electrodo, and it is moistened with parafline-oil or like carbonaceous liquid in the
following manner :-Four to six drops per minute of the oil are allowed to drop from
a reservoir, and are led by a wire e upon the upper end of the plug. This is for the
purpose only of causing one end of the plug to be continually moistened. The
remainder of the plug acts as a retarder to the vapor arising from this moistened end,
produced by the heat of the electrode. A minute quantity only of hydrocarbon vapor
is by these means formed at any one time, and in consequence of the obstruction it
mocis with from the plug in its passage up the electrode, before it enters the are, the
vapor is detained in the electrode sufficiently long to cause this minuto quantity
of vapor to be raised to a very intense heat before it is allowed to enter into
the arc.
In Figure 3 the arrangement is similar to that described in respect to Figure 2,
but, this being an upper electrodo, the form of the tube at its end is different.
In order to prevent the hydrocarbon from being absorbed by the porous carbon
electrode and to saturate the same, and so to escape in vapor before it reaches the arc,
I line the interior passage in the electrode with an enamel consisting of hard pitch or
bitumen dissolved in a solvent. This enamel I apply with a brush and allow it to
harden. In the same way I coat the end of the electrode where the same is
inserted into the box, and the exterior surface of the carhon may be similarly
coated if desired. Thus the hydrocarbon liquid is kept from contact with the porous
surface of the electrode.
I would state that I am aware of the Patent granted to Orazio Lugo, No. 207,754
in the United States of America in which hollow electrodes are proposed to bo
employed with wicks, which convey hydrocarbon oil from end to end of the electrodo
and up to the point of the electrode where the oil is vaporized and ignited. The effect
of this is to cool the electrode where it should for my purpose be most intensely
heated, and also to deposit carbon upon it, while in my case the hydrocarbon is
all consumed. My Invention differs essentially from this, in that I do not permit
the liquid to be conveyed to the point of the electrode where the light is exhibited.
I do not cool the point of the electrode, nor do I deposit carbon upon it, for I find if
these things be done that (although no doubt the electrode is rendered more
durable) the light is greatly decreased. I therefore, while supplying to the arc a
limited quantity of hydrocarbon vapor and that at an intense heat, not only carefully
maintain the heat at the point of the electrode, but also greatly intensify it, not
permitting the liquid to approach it, and substituting for a wick a tight fibrous plug
a short way only up the interior of the electrode.
Having now particularly described and ascertained the nature of my enid Inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. In an arc lamp, the combination consisting of carbon electrodes (one or both hollow)
connected with an electric sonrce and usual devices for the production of the electric
are between the electrodes, a box containing vaseline or other semi-liquid hydro-
carbon attached to the end of the hollow electrode farthest away from the arc and a
tightly fitting fibrous plug inserted a short way up the electrode at the end which
enters the box, and a space within the electrode void of fibrous plug or packing
between the packing at one end and the are at the other.
2. In an arc lamp, the combination consisting of carbon electrodes (one or both
hollow) connected with an electric source and usual dovicos for the production of the
electric arc between the electrodes, a tightly fitting fibrous plug inserted a short way
up the hollow electrode, a space within the electrode void of fibrous plug or packing
between the packing at one end and the arc at the other, and means for supplying
liquid hydrocarbon to the plug or packing at the end farthest away from the arc.
3. In an are lamp, the combination consisting of carbon electrodes, (one or both
hollow) connected with an electric source and usual devices for the production of the
electric are between the electrodes, a tightly-fitting fibrous plug inserted into the hollow

page_text: electrode, a lining of bituminous enamel to the passage in the hollow carbon electrode,
and means for supplying liquid hydrocarbon to the plug or packing at the end
farthest away from the arc.
4. In an arc lamp in which a hydrocarbon is supplied to the arc; the use for this
purpose of a hollow carbon electrode coated either within or without or both with
enamel consisting of hard pitch or bitumen dissolved in a solvent.
Dated this 8th day of May 1890
CARPMAEL & Co.,
Agents.