Improvements in Arc Lamps.
Year: 1897

page_text: Improvements in Arc Lamps.
JOSEPH DEVONPORT FINNEY ANDREWS, 45, Fulham Park Gardens, Fulham, S.W.,
Electrical Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in electric arc lamps. I arrange the carbons
in line with one another in suitable holders. To one of the holders I attach an armature
in the form of an iron rod or tube, and I mount this in an outer tube so that it can
slide within and be guided. I prefer to close one end of the guide tube so that the
armature as it is caused to approach the closed end will compress the air or fluid
within the tube. Around the outside of this guide tube I form a coil of insulated
wire. When an electric current is made to pass through the coil of wire the iron
armature within the tube would be drawn into the tube in the known manner. The
air being compressed within the tube would lessen the speed of motion and when
an electric arc is being struck between the carbons the movement of the carbons
would be stended. I extend the guide tube beyond the end of the coil of wire so
as to guide the core or armature as it enters and to effect the compressure of the
air from the commencement which could not be the case without packing if the guide
tube where not thus extended. I sometimes close both ends of the guide tube
leaving however an aperature at one end so that the end of the carbon can be
inserted in its holder the carbon thus protruding from the end of the guide tube.
I may adopt means of checking the rapid movement of the armature within the
solenoid and then not enclose either end of the guide tube.
I prefer to encase the coil of wire in iron.
Instead of attaching to carbon to an armature moving within a coil I sometimes
prefer to attach it to an iron tabe arranged to move on the outside of the coil, in
this case the iron tube would form an air cylinder fitting on to the coil, the coil being
suitably covered to form a piston and would be a fixture, the iron tube or cylinder
being provided with a guide tube extended beyond its end so that it would guide the
cylinder when it has left or leaving the coil. Or instead of the guide tube being
fixed to the moveable cylinder I may arrange a fixed guide tube outside of it so
that the cylinder would move within it and outside of the coil as already described.
I may arrange the outer guide tube above described to be the cylinder and the iron
tube surrounding the coil to be the piston or I may attach the coil to the carbon
holder and arrange it to move within the outer iron cylinder & form a piston
to it as before.
The cylinder in this case would be extended by a non-magnetic extension so as
to form the guide tube.
Instead of forming any coil upon a non-magnetic bobbin I may form it on an iron
tube up the centre of which I would arrange the rod armature carrying the carbon
to glide in suitable guides, or I may wind the coil upon a non-magnetic bobbin
down the centre of which I would arrange a fixed rod or tube around this rod I would
have a space into which I would arrange a tube armature to glide. In this case
& in any of the above modifications in which I employ an iron envelope round

page_text: the outside of the coil I may construct the coil shorter than the tubes and armature.
I may make the tubes tapered and they may be thicker at one end than the other
& likewise the armature may be tapered & heavier at one end than the other, in
any of the above modifications I may find it convenient to carry some or all of the
weight of the armature by a spring or counterweight the latter being arranged by
a cord or cords passing over a pulley or pulleys. When I use springs to carry or
relieve the weight of the armature I prefer to employ one of special construction
consisting of 2 springs one pulling against the other, the armature being attached
between them. By this contrivance I could obtain the same pull throughout the
movement of the armature.
I prefer to use the above modifications of my lamp in conjunction with globes
around the arc which do not permit of free circulation of fresh air & I prefer to
construct the globes with an inner lining which would be somewhat smaller than
the interior of the outer globe so as to leave an air space between the 2. I prefer
to construct this lining of mica. I I attach the globes within to a separate fixing or
to the end of the guide tube in any suitable manner.
In some cases I may make the guide tube of glass having the coil of wire upon
it with its non-magnetic bobbin or iron tube bobbin & form the air tight globe
upon the end of the glass tube in this case I may employ the globe so formed as the
inner globe or lining or I may dispense with the outer globe.
I may exhaust the air from the globe enclosing the carbons or I may fill it with
any suitable atmosphere or gas.
When I desire to construct my lamp with an arc in a fixed position I prefer to
suspend the globe containing one of the carbons fixed to it by a suitable carbon
holder attached to a cord, band, or chain which is passed over a pulley & attached
at its other end to the armature.
100
1000
JOSEPH DEVONPORT FINNEY ANDREWS, 45, Fulham Park Gardens, Fulham, S.W.,
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 :-
My invention relates to improvements in electric arc lamps, I arrange the
carbons in line with one another in suitable holders. To one of the holders I attach
an armature in the form of an iron rod or tube and I mount this in an outer tube so
that it can slide within and be guided, I prefer to close one end of this guide tube
so that the armature as it is caused to approach the closed end will compress the
air or fluid within the tube. Around the outside of this guide tube I form a coil of
insulated wire. When an electric current is made to pass through the coil of wire
the iron armature within the tube would be drawn into the tube in the known
manner. The air being compressed within the tube should lessen the speed of
motion and when an electric arc is being struck between the carbons the movement
of the carbons would be steadied. I extend the guide tube beyond the end of the
coil of wire so as to guide the core or armature as it enters and to effect the
compression of the air from the commencement which could not be the case without
packing if the guide tube were not thus extended. I sometimes close both ends of
the guide tube leaving however an aperture on one end so that the end of the carbon
can be inserted in its holder the carbon thus protruding from the end of the guide

page_text: tube. I may adopt other means of checking the rapid movement of the armature
within the solenoid and then not enclose either end of the guide tube.
I prefer to encase the coil of wire in iron.
Instead of attaching the carbon to an armature moving within a coil I sometimes
prefer to attach it to an iron tube arranged to move on the outside of the coil, in
this case the iron tube would form an air cylinder fitting on to the coil, the coil
being suitably covered to form a piston and would be a fixture, the iron tube or
cylinder being provided with a guide tube extended beyond its end so that it would
guide the cylinder when it has left or leaving the coil, or instead of the guide tube
being fixed to the movable cylinder I may arrange a fixed guide tube outside of it
so that the cylinder would move within it and outside of the coil as already described.
I may arrange the outer guide tube above described to be the cylinder and the iron
tube surrounding the coil to be the piston or I may attach the coil to the carbon
holder and arrange it to move within the outer iron cylinder and form a piston to it
as before. The cylinder in this case would be extended by a non-magnetic extension
so as to form the guide tube.
Instead of forming my coil upon a non-magnetic bobbin I may form it on iron
tube up the centre of which I would arrange the rod armature carrying the carbon
to glide in suitable guides or I may wind the coil upon a non-magnetic bobbin down
the centre of which I would arrange a fixed rod or tube, around this rod I would
leave a space into which I would arrange a tube armature to glide. In this case
and in any of the above modifications in which I employ an iron envelope round the
outside of the coil I may construct the coil shorter than the tubes and armature. I
may make the tubes tapered and they may be thicker at one end than the other
and likewise the armature may be tapered and heavier at one end than the other, in
any of the above modifications I may find it convenient to carry some or all of the
weight of the armature by a spring or counterweight the latter being arranged by
a cord or cords passing over a pulley or pulleys. When I use springs to carry or
relieve the weight of the armature I prefer to employ one of special construction
consisting of two springs one pulling against the other, the armature being attached
between them. By this contrivance I would obtain the same pull throughout the
movement of the armature.
I prefer to use the above modifications of my lamp in conjunction with globes
around the arc which do not permit of free circulation of fresh air and I prefer to
construct the globes with an inner lining which would be somewhat smaller than
the interior of the outer globe so as to leave an air space between the two. I
prefer to construct this lining of mica I attach the globes within to a separate
fixing or to the end of the guide tube in any suitable manner.
In some cases I may make the guide tube of glass having the coil of wire upon
it with its non-magnetic bobbin or iron tube bobbin and form the air tight globe
upon the end of the glass tube, in this case I may employ the globe so
formed as the inner globe or lining or I may dispense with the outer globe.
I may exhaust the air from the globe enclosing the carbons or I may fill it with
any suitable atmosphere or gas.
When I desire to construct my lamp with an arc in a fixed position I prefer to
suspend the globe containing one of the carbons fixed to it by a suitable carbon
holder attached to a cord, band, or chain which is passed over a pulley and
attached at its other end to the armature.
In Figure 1, I illustrate one form of my invention. B is an iron core arranged to
slide in a tube A A which is closed at the upper end. Upon this tube I mount a
coil of insulated wire C through which the current of the lamp is made to pass. A
carbon D is attached to the moving rod B and below it in direct line I arrange
another carbon E suitably supported in any known manner. When the lamp is
idle the carbons (except in certain modifications) touch. When the lamp is in use
the current will pass from one carbon to the other and by connection F through
the coil of wire and away. The effect of the current in the coil would be to draw
up the rod B and thus separate the carbons and form an arc. In doing so there

page_text: would be a tendency to too rapid a movement of the rod which would cause the
phenomenon known as hunting. To prevent this I close the upper end of the
tube A so that the rod in ascending would compress the air thereby checking any
rapid movement. As the carbons consume the arc would lengthen and which
would weaken the current and allow the rod to descend sufficiently to reinstate the
arc at its correct length. The even effect of the pull upon the core or rod by the
current throughout the length is obtained by suitable dimensions of the coil and
core. I prefer to extend the tube A beyond the end of the solenoid C in order
more effectively to guide the rod B in a straight line.
In some cases I find it beneficial to enclose the solenoid in an iron case G.
In Fig. 2. I illustrate a modification of part of my invention in which I arrange
an iron tube to move on the outside of a fixed solenoid instead of inside, A is the
tube of which the part H is non-magnetic. C the solenoid carried by the rod F
provided with a broad cheek B fitting the inside of the tube A and thus forming a
piston within it, by which the air would be compressed in the lower portion G.
The action of the lamp is the same as that of Fig. 1. Instead of fixing
the coil I may attach it to the movable carbon and fix the tube as in Fig. 3
in which A is the tube of which the part H is non-magnetic, C the solenoid with a
piston B on the upper end, which would effect compression of the air in the
upper part G when it is drawn in by force of the current in the coil. The action of
the lamp in this case being exactly similar to that shown in Fig. 1.
In Fig. 4. I illustrate that part of my invention by which I increase the
burning life of the carbons. A is the globe or cylinder of glass surrounding
the carbons B and C which are carried in suitable holders. Between the free ends
the electric arc D would be formed and maintained by any suitable carbon
feeding contrivance. In order to prevent or lessen the deposit on the globe I
provide an inner lining E of glass or mica held by any convenient means on the
inner surface of the globe at a slight distance from it so as to leave an air space F.
I may construct my globes in any of the usual shapes.
In Fig. 5. I illustrate my combined guide tube containing a magnetic core and
a globe. A is the guide tube constructed of non-maguetic material preferably
glass with a globe B formed on the end of it which may be made in one piece
with the guide tube when the latter is of glass, but when the tube is of brass or
other similar material the globe would be attached to it in any suitable inauner at
the point C, preferably air tight. D is the core carrying the carbon as in tho case
of Fig. 1. E is the solenoid preferably wound upon a separate bobbin F. The
guide tube containing the core and carbons together with the globe could thus be
removed from the coil for renewals.
In Fig. 6. I illustrate my method of maintaining the arc in approximately one
position. Attached to the upper end of the core B are cords A A which pass over
running pulleys C C and are attached by their ctber ends to two rods D D guided
in guides E F. To the lower ends of these rods I attach the globe F surrounding
the arc and containing the lower carbon. The core B is made heavier than the
globe F consequently the carbons G and H touch when there is no current passing
soon as current traverses the carbons and the coil 1 an arc will be
establisbed in the known manner and the regulation will continue as previously
described in connection with Fig. 1.
but so
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. The combination in an electric are lanp of a long solenoid, a long core or
tube and a long dash pot to act contiuccusly wit cut gearing throughout the
length or feeding range of the carbons substantially as described with reference
to Figs. 1, 2, 3, 5, & 6.
2. The construction of an are enclosing globe consisting of a globe provided

page_text: with an inner lining to prevent or lessen the darkening of the glass substantially
as described in relation to Fig. 4.
3. Combining the core guide tube and the arc enclosing globe substantially as
described with reference to Fig. 5.
4. Constructing an arc lamp with a core and solenoid and an arc enclosing
globe in which the lower carbon is fixed, the core and globe being suspended
on opposite ends of a cord passed over pulleys for the purpose of retaining the arc
in a nearly fixed position, as described with reference to Fig. 6.
Dated this Oth dow of Tule 1808
J. D. F. ANDREWS.