AN IMPROVED SEMI-INCANDESCENT LAMP
Year: 1885

page_text: I THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster
Civil Engineer do hereby declare the nature of my invention for "AN IMPROVED
SEMI-INCANDESCENT LAMP a communication to me from abroad by Oscar Fredrik
Jönsson of Stockholm Sweden Engineer to be as follows:-
The object of this invention is the production of a semi-incandescent lamp in
which the carbon is surrounded by a confined quantity of air enclosed partly by
the tube of the lamp and partly by a glass globe, whereby the carbon forming
part of a closed circuit is caused to glow in the midst of an inert gas, chiefly azolic
gas and carbonic acid, owing to which the carbon will be consumed very slowly
and the light rendered uniform because the carbon will not be exposed to draught
and because the combustion takes place in a confined and as far as possible constant
gas mixture.
The lamp consists of two metallic tubes and placed one in another of which the
interior one is in conducting connection with one conductor, and the exterior tube
with the other conductor. The tubes are insulated the one from the other by
means of gypsum or other insulating matter. A stopper closes the top of the
interior tube and serves at the same time as a suspending hook for the lamp. This
tube encloses a carbon rod the top of which is introduced into a support fixed into
and insulated from a weight sliding in the tube. This weight may be made heavier
or lighter by adding or taking off small rings. The carbon rod passes through a
kind of pincers fixed at the bottom of the tube one jaw of the pincers is stationary
but the other is moveable about a joint and kept pressed against the carbon by
means of an adjustable weight. The lower end of the carbon rests upon a piece of
brass fixed on the end of a curved metal bar screwed on the exterior tube. The
lower end of the lamp is enclosed by a glass globe hermetically attached to a flange
fixed on the outer tube.

page_text: The electrical current passes to the interior tube and the pincers and from the
latter into the carbon rod and the piece of brass on which it abuts, then to the
outer tube. The glowing carbon point is at first burnt, so that oxygen is consumed
in the hermetically closed glass globe. When this has occurred the combustion will
be diminished, and the carbon consumed more slowly.
In proportion as the carbon is consumed it sinks down owing to the weight so
that its lower end always bears against the brass piece. When the carbon is
entirely consumed, the stopper is screwed off, and the weight removed in order to
apply another carbon rod which is introduced in the lamp, and then the stopper
screwed on as before and the lamp may be again lighted.

page_text: I, THORSTEN NORDENFELT of 53 Parliament Street in the City of Westminster
Civil Engineer, do hereby declare the nature of this invention (a communication
from abroad by Oscar Fredrik Jönsson of Stockholm Sweden Engineer) 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 this invention is the production of a semi-incandescent lamp in
which the carbon is surrounded by a confined quantity of air enclosed partly by
the tube of the lamp and partly by a glass globe, whereby the carbon forming
part of a closed circuit is caused to glow in the midst of an inert gas, chiefly azolic
gas and carbonic acid, owing to which the carbon will be consumed very slowly
and the light rendered uniforın because the carbon will not be exposed to draught
and because the combustion takes place in a confined and as far as possible constant
gas mixture.
On the annexed drawing-Figure 1 is a longitudinal section and Figure 2 an
elevation of the lamp. The lamp consists of two metallic tubes A and B placed
one in another of which the interior one A is in conducting connection with a
metallic ring C and the pole screw D for one conductor, and the exterior tube B is
in conducting connection with the metallic ring E and the pole screw F for the
other conductor. The tube A is insulated from the tube B by means of gypsum or
other insulating matter, and the metallic rings C and E are insulated one from
another by means of an intermediate block G of ebonite or other insulating
matter, H is a stopper for closing the top of the interior tube and serving at the
same time as a suspending hook for the lamp. The tube A encloses a carbon rod I
the top of which is introduced into a support K fixed into and insulated from a
weight L sliding in the tube A. This weight may be made heavier or lighter by
adding or taking off small rings M placed thereon. The carbon rod passes through
a kind of pincers fixed at the bottom of the tube A one jaw N of the pincers is
stationary but the other O is moveable about a joint and kept pressed against the
carbon by means of an adjustable weight P. The lower end of the carbon rests
upon a piece of brass Q fixed on the end of the curved metal bar R screwed on the
exterior tube B. The lower end of the lamp is enclosed by a glass globe S
hermetically attached to a flange T fixed on the tube B.
The electrical current enters from the circuit at the contact screw D in the
ring C and passes to the interior tube A and the pincers NO. From the latter the
current passes into the carbon rod I and into the piece of brass Q in contact
therewith, then to the bar R, the tube B, and the contact screw F. The glowing
carbon point between the pincers NO and the piece Q is at first burnt, so that
oxygen is consumed in the hermetically closed glass globe. When this has occurred
the combustion will be diminished and the carbon consumed more slowly.
In proportion as the carbon is consumed it sinks down owing to the weight L so
that its lower end always bears against the brass piece Q. When the carbon is
entirely consumed, the stopper H is screwed off, and the weight L removed in order
to apply another carbon rod which is introduced in the lamp, and then the stopper
screwed on as before and the lamp may be again lighted.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
(1.) A semi-incandescent lamp in which the carbon is surrounded by a confined
quantity of air enclosed partly by the tube of the lamp and partly by a glass
globe, whereby the carbon forming part of a closed circuit is caused to glow in the
midst of an inert gas, chiefly azolic gas and carbonic acid, owing to which the
carbon will be consumed very slowly and the light rendered uniform because
the carbon will not be exposed to draught and because the combustion takes place
in a confined and as far as possible constant gas mixture.
(2.) The arrangement of the lamp particularly with reference to the abutment
piece and the carbon rod passing through a suitable contact making nipper or
holder and resting against the abutment piece substantially as described and
represented.
(3.) The combination of the inner and outer metallic tubes A and B closed at
their upper ends and insulated from one another, the curved bar R the copper
block Qand the glass globe S carried at the lower end of the outer tube, the
carbon rod I carried within the inner tube and pressed downwards by a weight and
the nipper NO made to grasp the lower end of this carbon rod also by the action
of the weight.