Method of and Apparatus for Prolonging the Life of the Carbons in Electric Arc Lamps.
Year: 1891

page_text: COMPLETE SPECIFICATION.
A Method of and Apparatus for Prolonging the Life of the Carbons
in Electric Arc Lamps.
I, CHARLES WALTER HAZELTINE, a citizen of the United States, residing at
St. Louis, in the State of Missouri, United States of America, Travelling Sales-
man, 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 prolong the life of the carbons in electric arc
lamps whilst they are being consumed.
In carrying my invention into effect I apply in close proximity to the arc, a
protective tip or shield to prevent the rapid consumption of carbon. This tip or
shield is in the ordinary forms of arc lamp fed as the opposite carbon wears away;
and is automatically adjusted by any suitable means but by preference is fed by the
movement of the upper carbon, to which it is preferably applied.
The invention will be best understood by reference to the accompanying drawings
which by way of a type or example, and not as defining the scope of my invention,
illustrate one form of my apparatus.
Figure 1 is an elevation of an arc lamp having one form of that part of my
invention which constitutes the apparatus applied thereto.
Figure 2 is an enlarged view of the carbons near the arc, showing a part of the
protective tip or shield in section.
The same figures of reference indicate the same parts in the two views.
I have shown only in the accompanying drawings the outline of an arc lamp
and not represented the mechanism by which the are is maintained, as my
invention is independent of any special mechanism for regulating the arc, and
may be applied to any type of arc lamp. 5 is the casing of an arc lamp that
contains the mechanism which controls the arc. 6 is a housing in which the
carbon-carrier 7 plays up and down, and 8, 8 are the frame-pieces which sustain
the lower carbon 9 from the casing 5 of the lamp. 10 is the upper carbon,
which is secured to the carbon-carrier 7 before referred to. To this upper
carbon 10, and above and close to the arc, say one-eighth or quarter of an
inch therefrom, I apply a protective tip or shield 11 of refractory material,
such for example as baked clay, porcelain or the like, that has a perforation
therethrough which permits the upper carbon to feed freely through the same,
as the carbons burn away. In order to keep the protective tip or shield near
the arc and receive the resulting beneficial effect, it is necessary in the particular
arrangement shown, to feed the said tip or shield downward to compensate for
the burning away of the lower carbon. I preferably feed the protective tip or
shield downward by the movement of the upper carbon, and to effect this
purpose I for example secure pulleys 12, 12 to the said protective tip or shield,
over each of which pulleys passes a cord or chain 13. One end of each of the
cords is secured to the carbon-carrier 7 and the cords after being carried over
the pulleys 12, 12, pass around pulleys 14, 14 fixed to any suitable immovable

page_text: part of the lamp. The other ends of said cords are secured to a bail of the
movable pulleys 12. Each of the cords 13 may return upon itself three times
and will then make the feed of the protective tip or shield equal to one-third
of the feed of the upper carbon. In practice the lower carbon burns away
about half as fast as the upper carbon when my protective tip is applied as
shown. If for instance, the upper carbon has to feed through two inches to
compensate for its own consumption, it must also feed one inch in addition to
compensate for the consumption of the lower carbon. The feed of the upper
carbon will thus be three inches in the case supposed. To maintain the pro-
tective tip or shield in the same relative position with reference to the arc at
all times, it is necessary in the case assumed that the shield should be fed
In other
through one inch while the upper carbon is fed through three inches.
words the feed of the tip or shield should be one-third of the feed of the upper
carbon. Care should be taken that the tip be not fed faster than the lower
carbon burns away, clse the tip will in time envelope the arc and thus interfere
with the proper functions of the same. The tip should be fed if anything, a
little less than the rate of combustion of the lower carbon in order to have a
safe working margin.
I have found by experiment that a tip or shield applied to one of the carbons in
electric arc lamps, preferably the positive or upper carbon, will act to prolong the
life of the lower or negative carbon, which need not necessarily be furnished with a
tip. In other words, a single tip applied to one carbon will act to prolong the life
of both carbons.
By applying this simple device to an arc lamp, I have found by actual practice
that the consumption of carbons is decreased fully or even more than one-half, thus
making carbons burn twice as long as they otherwise would and this without in any
way decreasing the candle power. With this protective shield applied to an
ordinary single arc lamp, it can be made to burn the entire night through, or as
long as would a double arc lamp of the usual construction. I am unable to account
for this saving of carbon, and I do not wish to state any supposed theory of operation
by which this result is attained. The protective shield or tip may possibly prevent
the carrying away of any unconsumed carbon particles and their consequent
dissipation and loss in the air, or it may on the other hand operate to concentrate
such carbon particles upon the arc and secure their complete combustion. The
results here given have been reached in actual practice after repeated trials of
many days duration.
I desire it to be understood that I do not confine myself to pulleys or cords for
feeding the protective tip or shield as the upper carbon is fed, or to feeding the tip
or shield by the movement of the upper carbon, or to making the tip or shield of
any particular material. My protecting tip or shield can be applied to any existing
are lamp and does not necessitate any change in the mechanism of the lamp.
I may incidentally mention that the protective shield, when applied to the upper
carbon, also acts to prevent radiation of light above the said tip or shield which
therefore serves in effect as a reflector for the light of the arc, diffusing it in all
directions where needed. When such a protective tip is used, it causes the arc to
spread and lose its defined limits, so making the light softer and more agreeable to
the eyes.
I am aware that before the date of my invention tips somewhat resembling mine
have been employed, some for purposes of reflection, and some for purposes of
incandescence. Such tips however differed essentially from mine and were employed
for a different purpose and in a different manner.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The method of prolonging the life of the carbons in electric are lamps substan-
+ill..

page_text: 2. The apparatus for prolonging the life of the carbons in electric arc lamps
substantially as set forth.
3. The use of a protecting tip or shield substantially as and for the purpose set
forth.
4. In an electric arc lamp the employment of a device for maintaining a protecting
tip or shield as herein set forth in its required position with respect to the arc as the
carbons burn away.
Dated thin 9th day of Tona 1901
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, Strand, W.C., Applicant's Patent Agent.