IMPROVEMENTS IN ELECTRIC ARC LAMPS
Year: 1884

page_text: I, PHILIP MIDDLETON JUSTICE of 55 and 56, Chancery Lane in the County
of Middlesex, Fellow of the Institute of Patent Agents do hereby declare the
nature of said Invention for IMPROVEMENTS IN ELECTRIC ARC LAMPS to be as
follows:-
This Invention relates to electric arc lamps, and its object is to prevent the rapid
consumption of the carbons, and to produce a clear and steady light which will not
be effected by the circulation of air either upon the outside or in the interior of the
globe in which the electric light is formed.
In arc lamps as now commonly used the carbon electrodes are rapidly consumed
by oxidation due to the free access of air to the globe in which they are contained.
As the light produced is not due in any applicable amount to the combustion of,
the carbon, the oxygen of the atmosphere may be excluded, provided the free
movement of the carbon, be not interfered with, and means be found to prevent
breaking of the globe, by reason of the expansion of the inclosed air or other gases.
The main feature of my Invention consists therefore in enclosing the electrodes in
a globe or chamber, air tight at the bottom and opening at the top into an open
chamber or box which contains the regulating mechanism by which the moving
electrode is properly advanced.
It has been found by experiment that if the globe or chamber enclosing the
electrodes be air tight at the bottom and on all sides it may be open at the top
to admit the passage of the electrode and its holder from the regulator box or
chamber without any diaphram or stuffing box, or any close contact of the carbon
or its holder with the walls of the tube or passage between the globe or
chamber of the are and that of the regulating apparatus. Nor is it essential
that the regulator box itself should be air tight but it may be of ordinary
open construction.
The arc chamber at the commencement of the work will be filled with
atmospheric air. So long as any free oxygen remains in this air, the carbon
will be consumed resulting in the production of carbonous oxide gas, and this
action soon terminating the oxygen of the air is replaced by a heavy carbonous
oxide gas which mixed with the nitrogen is still heavier than the air and remains
[Price B71

page_text: by its gravity in the arc globe or chamber. As no further oxygen is supplied
combustion of carbon ceases. But any expansion due to the heat or to the formation
of carbonic oxide on relighting will find relief through the passage to the regulator
box or through valves specially provided as hereinafter explained. Besides the
movement of the upper electrodes is perfectly free.
The Invention is limited to the means for securing free movement of the
electrodes, and for avoiding fracture of the globe by reason of expansion of the
inclosed gases.
An ordinary regulator box containing any ordinary regulating
apparatus for advancing the carbon holder is employed. To the bottom of said
box is attached a short tubular box, by means of suitable flanges and packing to
form an air tight joint. Into this tube fits a second tube so connected to the upper
cap as to be air tight. The tubular box is long enough to form a guide for the
second tube which is adapted to slip therein and is provided with a packing ring.
Between the upper end of the tube and the end of the regulator box is a spring
which tends to force the second tube downward but which permits it to be raised
for removal.
The upper part of the globe is formed with an opening, the edges of which are
ground and which with a packing ring makes an air tight joint with the cap. The
lower surface of this cap may be polished if desired and act as a reflector. The
lower opening of the globe has similar ground edges and is fitted to the lower cap
with an air tight joint also formed by a packing ring. Said lower cap has a
tubular extension which forms a lower carbon holder, the lower end of the
extension being air tight, so that the globe is hermetically closed in its lower
part. This cap however is provided with valves one opening outwardly and the
other inwardly. The upper carbon holder moves loosely in the tube without any
such close contact as will interfere with its movement and above this is the
ordinary open box so that the regulating apparatus may cause the carbon to move
as freely as in ordinary open globes.
As heretofore explained the gases formed by combustion in the atmospheric air
contained in the globe at the beginning of the formation of the arc, are heavier
than the air itself and will not therefor rise or escape through the thin annular
passage in the tube, and through the regulator box and remaining in the globe
prevent any access of air to support combustion of the carbon.
In case of any expansion or contraction of the air or gases within the globe so
sudden and great as not find sufficient outlet through the second tube before
mentioned, one of the valves will open according to the direction of the pressure
and establish equilibrium without danger of breaking the globe. In practice
however this would seldom be required as there is sufficient vent through the
second tube under ordinary circumstances. But with these valves the regulator
box ought also be made air tight.

page_text: .
I, PHILIP MIDDLETON, JUSTICE of 55 and 56 Chancery Lane in the County
of Middlesex, Fellow of the Institute of Patent Agents do hereby declare the
nature of said Invention for "IMPROVEMENTS IN ELECTRIC ARC LAMPS" and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :—
This Invention relates to electric arc lamps and its object is to prevent the rapid
consumption of the carbons, and to produce a clear and steady light which will not
be affected by the circulation of air either upon the outside or in the interior of the
globe in which the electric light is formed.
In arc lamps as now commonly used the carbon electrodes are rapidly consumed
by oxidation due to the free access of air to the globe in which they are contained.
As the light produced is not due in any applicable amount to the combustion of
the carbon, the oxygen of the atmosphere may be excluded provided the free
movement of the carbon be not interfered with and means be found to prevent
breaking of the globe by reason of the expansion of the enclosed air or other gases.
The main feature of my Invention consists therefore in enclosing the electrodes in
a globe or chamber, air tight at the bottom and opening at the top into an open
chamber or box which contains the regulating mechanism by which the moving
electrode is properly advanced..
It has been found by experiment that if the globe or chamber enclosing the
electrodes be air tight at the bottom and on all sides it may be open at the top to
admit the passage of the electrode and its holder from the regulator box or
chamber without any diaphragm or stuffing box or any close contact of the carbon,
or its holder with the walls of the tube or passage between the globe or chamber
of the arc and that of the regulating apparatus. Nor is it essential that the
regulator box itself should be air tight but it may be of ordinary open construction.
The arc chamber at the commencement of the work will be filled with atmospheric
air. So long as any free oxygen remains in this air the carbon will be consumed
resulting in the production of carbonous oxide gas and this action soon terminating,
the oxygen of the air is replaced by a heavy carbonous oxide gas which mixed with
the nitrogen is still heavier than the air and remains by its gravity in the are
globe or chamber.
As no further oxygen is supplied combustion of carbon ceases.
But any expansion due to the heat or to the formation of carbonic oxide on
relighting will find relief through the passage to the regulator box or through
valves, specially provided as hereinafter explained. Besides the movement of the
upper electrodes is perfectly free.
The Invention is limited to the means for securing free movement of the
electrodes and for avoiding fracture of the globe by reason of expansion of the
enclosed gases.
In the accompanying Drawings is shown the improved apparatus with the
globe and its connections in central vertical section the other parts being in side
elevation.
In these Drawings X, represents an ordinary regulator box containing any
ordinary regulating apparatus for advancing the carbon holder H. To the bottom
of this box is attached a tubular box B, by means of suitable flanges and packing,
to form an air tight joint. Into this tube fits a tube C, connected to the upper
cap Z, so as to be air tight. The box B is long enough to form a guide for the
tube O, which is adapted to slip therein and is provided with a packing ring R³.
Between the upper end of the tube and the end of the regulator box is a spring S,

page_text: which tends to force the tube C, downward but which permits the tube to be raised
for removal. The upper part of the globe A. is formed with an opening the edges
of which are ground and which with a packing ring R2 makes an air tight joint
with the cap Z³. The lower surface of this cap may be polished if desired and act
as a reflector. The lower opening of the globe has similar ground edges and is
fitted to the lower cap by an air tight joint also formed by the packing ring R
Said lower cap has a tubular extension Z, which forms a lower carbon holder the
lower end of the extension being air tight so that the globe. is hermetically closed
in its lower part.
This cap however is provided with valves V-V. one opening outwardly and the
other inwardly.
The upper carbon holder H moves loosely in the tube C without any such close
contact as will interfere with its movement and above this is the ordinary open box
so that the regulating apparatus may cause the carbon to move as freely as in
ordinary open globes.
As heretofore explained the gases formed by combustion in the atmospheric air
contained in the globe A at the beginning of the formation of the arc, are heavier
than the air itself and will not therefore rise or escape through the thin annular
passage in the tube C. and through the regulator box, and remaining in the globe A
prevent any access of air to support combustion of the carbon.
In case of any expansion or contraction of the air or gases within the globe so
sudden and great as not to find sufficient outlet through the tube C, one of the
valves will open according to the direction of the pressure and establish
equilibrium without danger of breaking the globe. In practice however this
would seldom be required as there is sufficient vent through the tube C under
ordinary circumstances. But with these valves the regulator box ought also be
made air tight.
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 :
In an electric arc lamp a globe or chamber for the arc, closed air tight at the
bottom and on all sides, a regulator above the globe or chamber an air tight tube
forming a passage between the regulator, and the globe or chamber, and a carbon
holder extending loosely through the said tube whereby the gases are retained in
the globe undue pressure avoided and free movement of the carbon secured all
substantially as described.
Dated this 10th day of June AD 1884