A System of Reflectors for Double Globe Electric Arc Lamps
Year: 1898

page_text: Date of Application, 16th Aug., 1898-Accepted, 29th Oct., 1898
A System of Reflectors for Double Globe Electric Arc Lamps,
I, OTTO VON MULMANN, of 30, Rue Ernest Allard, Brussels, Belgium, Electrical
Engineer, 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:-
With electric arc lamps in which the globe or cover enclosing the luminous
are is surrounded by an exterior globe according to the "Jandus system" reflec-
tors have been used arranged exterior to the outer globe like those generally used
with ordinary electric arc lamps where a single globe only protects the luminous
arc.
The interior surface of the ordinary single globe arc lamps are rapidly covered
by carbon dust arising from the combustion of the carbons but this carbon dust
is not deposited the same way in the interior globe of the double lamp.
In taking into consideration this special advantage of double globe lamps the
applicant has invented a special system of reflectors. These reflectors are placed
in the interior of the exterior globe and underneath the cap of the latter and
by this means not only is the lamp and reflector formed more compactly but the
distance between the luminous focus and the reflector is less than that of other
systems at present in use.
The invention may be carried into effect either by applying a coat of reflecting
enamel directly to the interior of the cap of the exterior globe or by arranging a
reflecting screen in the interior of this exterior globe under its cap."
The accompanying sheet of drawings illustrate different methods of carrying
the invention into effect.
Figure 1 is an elevation of the lower part of a double globe are lamp on the
Jandus system" with the outer globe in vertical section, the cap of this globe
being covered interiorly with a coat of reflecting enamel.
A coat of enamel a performing the office of a reflector which can be extended
downwards more or less as required is applied to the interior of the cap of the
outer globe A.
B is the interior globe enclosing the luminous arc.
As may be seen in the drawing hermetical joints are formed between the upper
opening of the globe A and the mounting of the lamp and between the lower
opening of the globe A and the plate d. This shelters the coat of enamel from
dust or other causes of deterioration coming from outside, while the globe B
protects it from the carbon dust coming from the luminous arc.
Figure 2 is a view similar to Figure 1 showing the application of a reflecting
screen to the interior of the exterior globe A, and,
Figure 3 is a perspective view of the screen and its adjacent parts on a larger
scale.
The screen a is fixed in place by the support C of the lower carbon holder on
the top of which it rests when the latter screwed into the mounting of the lamp,
though the said screen can be fixed in place by any other suitable means.
Price 8d ]

page_text: If the screen is too large to be introduced into the exterior globe in one piece
it can be constructed in two or more sections as is shown in Figure 3 of the
drawings.
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. In a double globe electric arc lamp a reflector arranged in the interior of
the exterior globe under the cap of the latter either produced by a coat of reflecting
enamel applied on the interior surface of the said exterior globe or applied in the
form of a reflecting screen constructed of one or several pieces substantially as
herein before described and shown in the accompanying drawings.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.
MARKS & CLERK;
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents.