Year: 1899

page_text: - '
C
ALFRED CHARLES BROWN, of 129, Algernon Road; Lewisham, -in-the County.of
London, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:
This invention consists in enclosing a rod of magnesia, lime or other refractory
oxide, or simple or compound material which although it may not be a con-
ductor of electricity at ordinary temperatures, becomes so when heated,-inside
a, carbon rod or tube, as a core foi the same; and either fixing the said 10d
tightly in the carbon or leaving it sufficiently loose to slide freely. Also in
using a pair of such combined rods or tubes with a common core rod as above
described extending across between & into each carbon, connected to a source of
electric supply, and used as the electrodes of an electric lamp; the carbons
being then preferably attached to the two sides or holders of an arc lamp, or
solenoid feed mechanism, so that when the current is switched on, and the
movement takes place which would in the ordinary way "strike the arc" the
central core becomes heated and conducts the current across,, the carbons then
separating fuïther until reaching an adjustable limiting stops The arrange-
ment, then thereafter acts as an incandescent lanip, using the carbon rods as
électrodes and the central core rod as the filament. Resistances or electro-
magnetic choking coils etc., may be inserted in circuit to prevent undue heating
and short circuiting, and to regulate the consumption of energy, and it will
be seen that should any accident happen to the core, rod or filament, the feed
mechanism will restore the circuit."
.
Or the carbons may in some cases be drawn apart by mechanism operated by
the rise of temperature generated by the are or incandescent, rod or filament,
acting by expanding a fluid or solid properly, arranged to transmit the, motion
to the carbons between adjustable or fixed limitations.
"
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Or the motion of the carbons may be imparted by hand, or by other-suitable
means
Instead of using a core capable of sliding in at least one of the carbons of the
pair used in a lamp and so forming a common core for both carbons extending
across the intervening space and forming an incandescent lamp as above described,
I may in some cases use a core of one of the above described materials, com-
pressed tightly into both carbons forming the pair, the refractory material
being then permissably formed of either a solid rod or a compressed powder and
the carbons being then used to form an ordinary are lamp with the advantage
of having a large percentage of the highly refractory material in a semi-con-
ducting state in the immediate arc.

page_text: Improvements in Electric Lamps.
ALFRED CHARLES BROWN, of 129, Algernon Road, Lewisham, in the County of
London, 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:—
This invention consists in enclosing a rod or filament of magnesia, lime or
other refractory oxide' or simple or compound material-which although it may
not be a conductor of electricity at ordinary temperatures, becomes so when
heated, inside a pair of carbon rods or tubes, as a core for the same; the rod
or filament extending across between and into each carbon tube, being preferably
fixed in one and loose in the other, or loose in both, and the carbon tubes which
are first allowed to touch end to end, being connected to a source of electric
supply, and used as the electrodes of an electric lamp; the carbons being prefer-
ably attached to the two sides or holders of an arc lamp, or solenoid feed
mechanism, so that when the current is switched on and the movement takes
place which would in the ordinary way strike the arc" the central core
becomes heated and conducts the current across, the carbons then separating
further until reaching adjustable limiting stops, and so breaking the arc which
first temporarily forms. The arrangement then thereafter acts as an incandescent
lamp, using the carbon rods as electrodes and the central core rod as the filament.
Resistances, or for alternating currents electio-magnetic choking coils et,
may be inserted in circuit to prevent undue heating and short circuiting, and to
regulate the consumption of energy.
Or the carbons may in some cases be drawn apart by mechanism' operated by
the rise of temperature generated by the arc or incandescent rod or filament,
acting by expanding a fluid or solid properly arranged to transmit the motion
to the carbons between adjustable or fixed limitations.
Or the motion of the carbons may be imparted by hand, or. by other suitable
means.
The accompanying drawing represents a typical form of this lamp in section,
but it must be distinctly understood that the non essential details may be varied
largely, the points which I consider vital to the invention being indicated in
the subjoined claiming clauses.
In the drawing A shews the body and framing of the lamp and B the iron-
core of a solenoid, the coil of which is wound in the space C (the actual windings
being omitted as they would be in section). The coil is joined across from the
terminal marked +, to the rod D, which is attached to, but insulated from, the
frame piece A. The opposite rod D¹ is also insulated from A but both are
connected with and carry the bottom cross piece E. This piece carries a clamp,
in which is affixed the carbon tube F. The fellow carbon tube G is clamped
to the solenoid core B and normally when the lamp is not in action touches
end on to Fas shewn. Within these two tubes is the filament indicated by
the dotted lines at II, and extending across into each of the tubes F & G and
. being preferably wedged or affixed into the lower one and loose in the upper.
Or it may be loose in both and simply dropped to the bottom of F being long
enough to extend partially also into G when the tubes are separated to their
maximum limit. When the lamp is out of action the circuit extends on from
the rod D through lower tube F, upper tube G, the iron core B of the solenoid
and the frame A to the terminal the connection between the core B and the
frame A being permanently ensured by the wire spiral J affixed to both, and
"'.

page_text: which may be in some cases made as an adjustable spring for the purpose of
varying the pressure on the core B, but for this purpose the weight of the core
itself can usually be made suficient, and the extent of motion of the latter is
made adjustable within fixed limits by the sciew or other suitable means.
When the current is switched on the solenoid becomes energised and draws
the core B up thus separating the tubes, and an arc temporarily forms at the
junction or dividing line L, the tubes F & G become heated for a portion of
their lengths and communicate the heat to the filament H, which is also heated
directly by the arc; the carbons ultimately separating further and exposing
the filament H until the core B comes against its limiting stop, and which
adjustment is set wide enough to break the arc, but the filament H (which may
be made of magnesia or other refractory substance as herein before described)
thereafter remains heated so long as the current is on, and conveys the current
across, so that the arrangement then forms an incandescent lamp.
The resistance of the coil, or an added resistance where desired, or, for
alternating currents, a small choking coil, serves to steady the current and
prevent over-heating.
The hanger may also be arranged so that the lamp may also in some cases be
suspended horizontally instead of vertically as shown, which former position
increases the side pressure of the filament H on one of the sides of the tubes F, G,
or their equivalents and which tubes may for some purposes be made of platinum
iredium or other metal instead of carbon, or the electrodes F & G instead of
being plain tubes may consist of two half tubes, or flat pieces with grooves,
sprung together so as to grip the filament H between them, with sufficient
pressure to make a good contact, but not sufficient to prevent the required end
movement. The filament itself may also if desired be flat or of other section
instead of round.
As stated above however the whole arrangement of moving mechanism may
be varied greatly without departing from the essential features of this inven-
tion. Any ordinary brake wheel, clutch, or other ordinary form of arc lamp or
are-striking mechanism may be substituted for the plain solenoid form shown,
or the sliding electrodes may be operated by hand.
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. In an electric lamp the use and employment of an incandescing body or
filament composed of a material which is a nonconductor of electricity at ordinary
temperatures, but becomes conductive at high temperatures, arranged so as to
form a common core for a pair of carbon tubes, or other holding and contacting
electrodes which have a permissable end movement, and are joined up in an
electric circuit, so that when the current is switched on and the tubes or elec-
trodes which have first been allowed to touch together, are drawn apart the
core or incandescing body is first heated up to conducting temperature by the
are temporarily formed, the heat being transferred to and along the filament
by the heated electrode with which it is in contact, and the filament then
conveying the current across between the tubes or electrodes after the latter
are separated far enough to break the arc, the arrangement thereafter forming
an incandescent lamp.
2. In an electric lamp, the combination of an incandescing body composed
of a material which is a non-conductor at ordinary temperatures and becomes
conducting only at high temperatures, a heating device for rendering said body
conducting, the same consisting of a normally conducting body in contact with
said incandescing body, means of generating heat within and in proximity to
said normally conducting body. of such intensity as to act by its transfer to
said incandescing body to render the latter an electrical conductor, and means
for discontinuing the generation of heat in said normally conducting body

page_text: when the temperature of said incandescing body has been raised sufficiently
to render it conducting.
3. In an electric lamp, the combination of an incandescing body composed
of a material which is a non-conductor at ordinary temperatures and becomes
conducting only at high temperatures, a heating device for rendering said
body conducting, the same consisting of a refractory normally conducting body
in contact with said incandescing body, means for generating heat within said
normally conducting body, of such intensity as to act by its transfei to said
incandescing body, to render the latter an electrical conductor, and means for
discontinuing the generation of heat in said normally conducting body when
the temperature of said incandescing body has been raised sufficiently to iender
it conducting.
.
4. In an electric lamp, the combination of an incandescent body composed
of a material which is a non-conductor at oidinary temperatures and becomes
conducting only at high temperatures, a heating device for rendering said body
conducting, the same consisting of a normally conducting body encompassing
said incandescing body, and means for generating heat within said normally
conducting body of such intensity as to act by its transfer to said incandescing
body to render the latter an electrical conductor.
5. The combination of an incandescent lamp the light-giving member of
which is a non-conductor at ordinary temperatures and a conductor at high
temperatures, and a steadying resistance or a choking coil in series with the lamp.
6. The combination of an incandescing body which is a non-conductor at
ordinary temperatures, but becomes conducting at high temperature, with a
pair of carbon tubes or other embracing and contacting electrodes having a
difference of electric potential between them, one at least of said electrodes being
arranged to slide in contact with the incandescing body whether the movement
be produced by hand or by the action of any mechanism, as and for the purposes
above described.
7. The combination of an incandescing body which may not be a conductor
at ordinary temperatures but becomes so at high temperatures with a pair of
electrodes one or both of which is or are capable of sliding in contact with said
incandescing body, the said electrodes being attached to and actuated by the
electromagnetic are striking and feed mechanism of an arc electric lamp,
or equivalent mechanism, so as to operate the said sliding electrodes auto-
matically.
8. The combination of a solenoid, core, a pair of sliding tubular or other
embracing and contacting electrodes and a rod or filament made of a material
which is a non-conductor of electricity at ordinary temperatures, but becomes
conductive at high temperatures all is described above and illustrated in the
accompanying drawing.
Dated this Oth dow of Doomlion 1000