Improvements in Economizing Apparatus for the Carbons of Electric Arc Lamps.
Year: 1895

page_text: Date of Application, 21st Feb., 1895-Accepted, 13th Apr., 1895
COMPLETE SPECIFICATION.
Improvements in Economizing Apparatus for the Carbons of Electric
Arc Lamps.
1, ALFRED ALBRECHT, Engineer, of 18 Landsberger-strasse Allee, Berlin in
the Empire of Germany, 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 :-
This invention has for its object to prolong, as much as possible, the duration
of burning of the carbon pencils in electric arc lamps and in this way to economize
the supply of material for such lamps, and to avoid the frequent replacement of
these carbon pencils.
The apparatus is represented on the accompanying drawing in Fig. 1 as a vertical
section. Figs. 2, 3, 4 and 5 shew a front elevation,.a vertical section, a plan and
the plan of framework of a modification of the same, respectively.
The apparatus consists essentially of a hollow receptacle comprising two parts a
and which enclose the points of the upper and lower carbon pencils c and d, and
which are connected together at e e. The thus connected parts are suspended in
an appropriate manner on wire-arms, preferably made of platinum-from the
point of the bottom carbon d and follow its movement as it burns down.
The wire arms are secured to a common guide ring 9 which loosely encircles
the carbon pencil d and which at the same time forms the bottom edge of the
lower part b. In a like manner a guide ring is also provided for the upper part a
and loosely encircles the top carbon pencil c.
The upper part a consists of a flat hollow frustum having its apex downward.
Inside the hollow space thus formed the point of the upper carbon pencil is located.
The base a¹, as well as the conical face a² of the frustum, is constructed of a
transparent material of great heat resisting power-preferably of mica. The inner
edge of the disc a' may be secured to a flange ¹ of the guide ring h.
Such a hollow body represents an excellent receptacle for the products of
oxidisation, their exit in an upward direction being prevented in a large circle.
At the same time this receptacle reduces the admission of fresh atmospheric air,
which consequently can only reach the carbon pencils in a previously heated state.
The point of the carbon pencil is therefore constantly in a space which contains
rarefied air and is always surrounded by hot gases. The desired prolongation of
the oxidisation and an improvement in the electric light are the consequences of
this arrangement.
The voltaic arc being formed underneath the hollow frustum a, its conical
surface a² serves at the same time as a very good reflector in the downward
direction whereby, in consequence of the transparent material, the radiation of the
electric light in the upward direction is in no way prevented.
In order that the upper carbon pencil may not be prevented from moving up and
down, it is necessary that inside the guide ring ha sufficient space for play be left
between it and said carbon pencil. This space for play gives to the gases
accumulated in the receptacle a, though to an exceedingly small extent, the means of
escaping in the upward direction-a circumstance which is slightly detrimental to
the effect of the apparatus. The interior of the guide-ring is therefore provided
with one or more circular grooves 2 where the air may settle down, and, as it is
proved by practical tests, successfully prevent the beforementioned exit of the
carbon vapours.

page_text: The bottom part for the bottom carbon pencil consists of a small reticulated
cage through which the air can freely pass, and preferably made of very fine wire
of platinum, nickel or of any other suitable material. This part acts similarly
to the larger upper part a, thongh not to such an extent.
The part b which glows when the lamp is lighted, may be smaller than the part a
because the latter partly transmits its effect to the carbon underneath. On the
other hand this part should surround the carbon point more closely, in order that
it may always be kept in a glowing state, and that the radiation of light may not
be prevented.
Finally it may be observed that the part below, might be dispensed with. In
this case the connection between the upper part a, h and the bottom part f, gis
preferably effected by two simple wire arms i which are fastened at one end to the
ring g and at the other to the inside or outside edge of the conical surface a². In
the drawing these connecting arms are represented by dotted lines. Without the
part b, of course, the carbon d beneath is less economised, but, nevertheless, there
will be a considerable economy because, as beforementioned, the hollow frustum a
transmits its effect partially to the under carbon.
The apparatus may be made in various sizes, according to the dimensions of the
arc lamps to be used.
As described above, the economizing apparatus for the bottom carbon consists of
a small cage with a reticulated surface of a material having great heat resisting
power. For this purpose it appears according to experience that only fine platinum
wire netting is appropriate. But as platinum renders the apparatus expensive, and
requires besides great care and precaution when exchanging the carbon pencil and
when cleaning the apparatus, the employment of metal wire netting may be
abandoned, and instead of it, a glass dish m with an open bottom (Figs. 2 and 3)
may be used. This glass dish has a hollow bead round the interior edge, in which
a detachable spring clip ring n with open ends n¹ rests. To this ring wire arms o
are secured which pass round the bottom edge of the glass dish or saucer and are
secured to the guide ring g. The latter encircles the bottom carbon pencil and
hangs from its point by means of platinum wires f. By the application of such a
glass saucer, the duration of the burning of the bottom carbon will not be prolonged
as considerably as by the use of platinum netting; but on the other hand advantages
are obtained which fully balance those small disadvantages.
The economizing receptacle for the upper carbon has in this modification
(Figs. 2-5) also undergone a variation. The shape of a hollow frustum is
maintained, but in this case it is inverted, the base being at the bottom. In order
to render the interior of this hollow frustum accessible for cleaning purposes it is
made in two detachable parts.
The surface of the cone p which is preferably made of mica, is fastened to a
small frame which (Fig. 5) is composed of an upper ring q and an under ring
connected to each other by arms s.
2"
The ring q is laid in a groove in the guide ring 1 for the upper carbon pencil
and may be made from the same piece of metal as the arms s, it being suitably
bent for the purpose.
The fastening of the mica cover p on the upper edge of the arms s is made in a
well known manner by cutting small flaps sin them, and fitting these flaps into
slits of the cover p and bending them down. The upper and under edges of the
mica cover p are pushed under oblique projections on the rings h and r. The under
ends of the arms s are strongly rivetted on ring r by means of cut-in and flat bent
flaps a².
The bottom plate of the upper hollow part a consists of a circular mica disc t
which has an aperture in its centre and the outside periphery of which is
encircled by a ring of sheet metal (Fig. 3). The detachable connection of this
bottom plate with the frustum above may be effected by any suitable means.
According to the example shewn in the drawing, the encircling ring u has for this
purpose several studs with heads v, and the ring r of the frustum has slots suitably

page_text: arranged with larger openings w into which those studs are inserted and fastened
like a bayonet joint.
By a short axial turning, both parts may be separated from each other and if
necessary, easily cleaned. Finally, a removable connection between the top and
the bottom parts is provided; which connection may also be effected in any
appropriate manner. According to the example shewn in the drawing, the
encircling ring u is provided for this purpose with a number of clamps pivotted
IC
to it and free to turn and clip the ring and the upper flat edge m¹ of the glass
saucer m.
"
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. An economizing apparatus for carbons in electric arc lamps, characterised by
a flat hollow frustum a, of transparent material, which encloses the upper carbon
point e, stores a great quantity of burning residue in its interior, diminishes to a
considerable extent the entrance of fresh air, and allows this air to enter only in a
previously warm state.
2. In the apparatus claimed under 1: the arrangement of grooves h³ in guide
ring of the hollow frustum a as a means for preventing the exit of gases through
the space left for play between the upper carbon c and the guide ring h.
3. In the apparatus claimed under 1, the arrangement of a second hollow part b
for the bottom carbon d which part has a perforated surface and serves at the
same time as a connection between the upper hollow part a and the supporting
ring 9
4. The replacing of the economizing receptacle for the bottom carbon, claimed
under 3 by a glass saucer m with an open bottom, the lower edge of which is
connected with the supporting ring 9 and its upper edge with the economizing
receptacle for the upper carbon pencil in a detachable manner substantially as
described and illustrated.
5. The replacing of the economizing receptacle for the upper carbon claimed
under 1 by a hollow frustum, the surface and base of which are connected together
in a detachable manner for cleaning purposes substantially as described.
Dated this 21st day of February 1895.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.