IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS AND IN THE PREPARATION OF THE CARBON FILAMENTS THEREFOR
Year: 1882

page_text: LETTERS PATENT to James Frederick Phillips of the firm of Phillips and
Leigh Engineers and Patent Agents 7 Southampton Buildings Chancery Lane
in the County of Middlesex for an Invention of "IMPROVEMENTS IN
INCANDESCENT ELECTRIC LAMPS AND IN THE PREPARATION OF THE CARBON
FILAMENTS THEREFOR" Communicated to me from abroad by Carl Heinrich
Florenz Müller of Hamburg Germany.
PROVISIONAL SPECIFICATION left by the said James Frederick Phillips
at the Office of the Commissioners of Patents on the 2nd October 1882.
JAMES FREDERICK PHILLIPS of the firm of Phillips and Leigh Engineers and
Patent Agents 7. Southampton Buildings Chancery Lane in the County of
Middlesex. "IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS AND IN THE
PREPARATION OF THE CARBON FILAMENTS THEREFOR A communication to me
from abroad by Carl Heinrich Florenz Müller of Hamburg Germany.
"
This Invention relates to improvements in electric lamps where the light is
produced by the incandescence of carbon in a vacuum and the objects of the
improvements are.
First. That around the axis of the lamp or bulb an equal lighting surface will
be visible. Second to impregnate the material (used for the carbon filament)
thoroughly before or after or before and after the carbonization with liquids which
will increase or render the material homogeneous and Third. The employment of a
material specially suitable for such carbons.
The carbon filaments of incandescent lamps when observed from certain points
of view only allows a single line to be visible because the ascending part of the
bow obscures the descending one and vice versa. The diffusion of the light at such
points of view is consequently proportionately smaller that at such points where
the complete bow can be see.
The carbons are shaped in such a manner as to form two cylindrical or conical

page_text: spirals crossing one another and may be jointed at the one end (or it may be
complete) and the free ends connected to the conducting wires in any convenient
manner,
A suitable material for such carbon filaments are strips of sugar cane which are
impregnated before the carbonization with a solution of hydrate of carbon in water
so as to make them more flexible. After being shaped and carbonized the carbon
coils are again impregnated with a solution of cellulose etc for filling all pores of
the vegetable fibre.
These two impregnations are executed in the vacuum in such a manner that the
carbon coils or filaments are placed in closed' receptacles from which the air is
extracted and which are filled before the readmission of air with the convenient
solution.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Frederick Phillips in the Great Seal Patent Office on the
2nd April 1883.
JAMES FREDERICK PHILLIPS of the Firm of Phillips & Leigh Engineers and
Patent Agents, Southampton Buildings Chancery Lane in the County of Middlesex
"IMPROVEMENTS IN INCANDESCENT ELECTRIC LAMPS AND IN THE PREPARATION OF
THE CARBON FILAMENTS THEREFOR A Communication from abroad by Carl
Heinrich Florenz Müller of Hamburg Germany
"
This Invention relates to improvements in electric lamps where the light is
produced by the incandescence of carbon in a vacuum and the objects of the
improvements are first, to shape the carbons in such a manner, that around the
axis of the lamp or bulb an equal lighting surface will be visible; second to
impregnate the material (used for the carbon filament) thoroughly before or after
or before and after the carbonisation with liquids, which will increase the
homogenity of the material; and third the employment of a material specially
suitable for such carbons. The carbon filaments of incandescent lamps when
observed from certain points of view only allow a single line or a little more to be
visible, because the ascending part of the bow obscures the descending one and
vice versa. The diffusion of the light at such points of view is proportionately
smaller than at such points where the complete bow can be seen. In order to
illustrate this observation the four most known incandescent lamps are shown in
the accompanying drawing in side elevations, each in two views: in figures la
and 1b the Edison lamp, in figure 28 and 2b the Lane Fox lamp, in figure 3a and 3b
the Swan lamp, and in figure 4a and 4b the Maxim Lamp. The figures 1ª, 2ª, 3ª
and 4 show the full form of the carbon, consequently to all points of view, where-
from the carbon is to be seen in that shape, the largest quantity of light will be
diffused; but where the carbons are visible only in the shape illustrated by
figures 1b, 2b, 3b and 4b, viz; from a line of view, at right angle to the former, both
parts of the bow cover each other entirely or nearly entirely as in the Swan lamp.
In consequence of the quantity of light diffused to such points is in the same
proportion smaller as the lighting surface decreases.
According to this invention the carbons are therefore shaped in such a manner
as to form two cylindrical or conical spirals, crossing one another, which are jointed
at the one end and the free ends connected to the conducting wires in any con-
venient manner. Figure 5ª, 5b, and 5° illustrate this form of the carbon a, figure 5ª
and 5b in side elevations from the same points of view as the four other lamps;
figure 5° is a view from below.
The best manner of manufacturing carbons of this shape is the following one.
Fine strips of sugar-cane are placed in a receptacle, which is hermetically closed
and the air pumped out; then a solution of hydrate of carbon in water is filled in
such receptacle, whereby all pores of the sugar-cane-fibre are impregnated with
the solution and simultaneously the fibre is made more flexible. Now the fibre is
shaped into the described or desired form and carbonized as usual, whereafter a
second impregnation with a solution of cellulose or similar material executed in
the same manner, will guarantee a complete homogenity of the fibre.
=
Having thus described the nature of this invention and in what manner the
same is or may be performed I would have it understood that what I claim is :-
First. In incandescent electric lamps a filament of the shape of a double spiral
the windings of which cross one another, substantially as described and illustrated
in the annexed drawings.

page_text: Second. The process of impregnating vegetable fibres for carbons for incan-
descent electric lamps in a vacuum with a solution of hydrate of carbon in water,
substantially as set forth and for the purpose specified.
Third. The process of impregnating carbons for incandescent electric lamps in a
vacuum with a solution of cellulose or other similar material substantially as and
for the purpose specified.
In witness whereof I the said James Frederick Phillips have hereunto set my
hand and seal this Second day of April in the year of our Lord One
thousand eight hundred and eighty three.