Improvements in Electric Arc Lighting.
Year: 1890

page_text: e of Application, 11th Aug., 1890-Accepted, 4th Oct., 1890
COMPLETE SPECIFICATION.
Improvements in Electric Arc Lighting.
I, SYDNEY PITT of Sutton in the County of Surrey, Gentleman (a communication
to me from abroad by Messrs. Sautter Harlé & Co., of 26 Avenue Suffron Paris)
do hereby declare the nature of this invention and in what manner the same
to be performed to be particularly described and ascertained in and by the following
statement:-
IS
The present invention has for its object improvements in electric arc lamps and
relates especially to the automatic maintenance of the luminous point in the focus of the
apparatus in which the lamp is placed, whether a lighthouse, a projector or any
other.
Up to the present time the fixity in space of the luminous electric focus has only
been obtained by the simultaneous approach of the two carbons; at an equal speed
when an alternating current is employed, producing an equal expenditure of the
electrodes; or with unequal speeds proportional to the expenditure of the electrodes
when a continuous current is employed.
When, in consequence of the breaking one of the carbons or from a speed of expendi-
ture different from that which had been expected, or perhaps from a defective initial
position, given to the electric focus, this is not in its normal position, it is adjusted to
it by hand, by means of suitable mechanism, whilst observing an image of the
flame projecting upon a screen upon which the focal plane has been marked by
a line.
The invention is an arrangement which results in the automatic replacing of the
luminous facet of one of the electrodes to the position which has been assigned to it
when for any reason it has left it. The position of the other electrode is regulated by
the variation of the intensity of the current or counter electro motor force of the
voltaic arc so as to maintain a constant separation of the carbons during work. The
sudden separation of the electrodes at the moment of lighting is brought about
by the application of an electro motor mechanism to one or other of the carbons.
Again, in order to obtain the fixity of the voltaic are I employ as I describe
further on one or more solenoids or permanent magnets or tubular electro magnets.
My invention is represented in the annexed drawings in which
Figure 1 is a section of my regulating thermo-motor.
Figure 2 is a plan.
Figure 3 is an elevation.
Figures 4, 4 and 5 show details.
Figure 6 shows one of the arrangements of the electro motor actuated by the
thermo-motor regulator and the necessary connections.
Figure 7 shows another arrangement of the apparatus working with a counter-
weight.
Figures 8, 9 and 10 show different positions which the carbons may occupy.
In Figures 1 to 5 A, is a screen. B, an extensible metallic wire. CC, straining
Screws. DD, screws for clamping the straining screws CC. E contact lever
against which the middle part of the wire B rests. F, support for the lever.
G, isolating supporting plate. H, spring serving to hold the lever E in close contact
with the middle part of the extensible wire. I and J, contact screws. K support for
the screw J. L, isolating supporting plate for the screw J. M fixed support of the
regulator. 1 and 2 carbons.
In Figure 6, P, is the case of the lamp. Q, the platform supporting the electro
LL
cowing to

page_text: spring of the lighting electro magnet. U, carbon carrier. u stem of the carbon
carrier moving vertically in the screw S. stop limiting the movement of u.
1, carbon, 3, controlling solenoid. M, regulating thermo-motor. N, support for the
regulator 0, wire leading from the negative pole of the arc.
In Figure 7 l' is the case of the lamp. Q the platform supporting lifting
mechanism. W a counter-weight, R¹ electro motor operating the lever V for dis-
engaging the stop lever V1. X guide stem supporting the lighting electro magnet T
and the carbon carrier U. t, armature of the lighting electro magnet. ¹ counter
spring of the lighting electro magnet. U carbon carrier-u stem of the carbon
carrier moving vertically in the stem X. stop limiting the movement of u.
3, controlling solenoid. M the regulating thermo-motor. N, support for the regulator.
O, wire leading from the negative pole of the arc.
In Figures 8, 9 and 10-(1) positive carbons, (2) negative carbons, (3) controlling
solenoids.
ACTION OF THE APPARATUS.
As long as the luminous facet of the lower carbon 1 is on the level of or above the
upper edge of the screen A it is seen by the wire B and heats it. The heated wire
lengthens and as the position of its ends does not vary it bends and allows the flexible
lever E, which the spring H presses against the middle part of the wire, to move.
This displacement, multiplied by the lever, breaks the contact between the end of the
lever and the screw J. If the luminous facet of the lower carbon descends below the
upper edge of the screen A it is no longer scen by the wire which immediately cools,
contracts, and pressing upon the flexible lever E, displaces it and reestablishes the
contact between its lower end and the screw J. Then the current passes and actuates
the electro-motor R (Figure 6) or the electro motor R (Figure 7).
The electro magnet according to Figure 6 moves a driving pawl which acts upon
the ratchet nuts to cause the displacement of the screw S. That of Figure 7 lifts the
stop and setting free a clock movement driven by a weight W allows the carbon to
be raised. When in consequence of its movement the luminous facet is again seen by
the wire this becomes heated, lengthens and yields; the flexible lever is again
displaced and the contact with the screw J ceases. The contact with a screw I placed
in front of the first may be utilised to send the current into a second mechanism,
similar to the first but acting in the contrary direction to lower the carbon in place of
raising it. The second contact may also be utilised to sound a call bell.
The electro motor R may be employed to raise instead of the carbon holder a move-
able support upon which the lamp stands.
The heating of the wire B may be obtained either by the direct radiation of the
luminous facet, as described above, or from the projection upon the wire of an image
of this facet obtained by means of a lons suitably arranged, or of a reflector.
This arrangement allows of the regulating thermo-motor being placed at a greater
distance from the lamp and of increasing its sensibility by enlarging the image of the
luminous point. The wire B may be replaced if desired by any other analogous
thermo-motor serving the same object.
I can also in place of the calorific power of the focus utilize its luminous power.
For this purpose the metallic wire B would be replaced by a wire or series of wires of
selenium or other suitable matter of which the resistance or the conducting power can
be influenced by light. The electric current traverses the wire B, the variations of
intensity of this current determined by the variations of the lighting cause the
stopping or the putting into action of the electro motor which raises the carbon.
-
The mechanism for separating the carbons at the moment of lighting operates as
follows When the principal current is sent to the lamp (the carbons being in
contact) it passes in the electro-magnet T T (Figures 6 and 7) and this attracts the
armature overcoming the action of the antagonistic spring and separates the
carbons. The current which acts upon the electro-magnet R. Figure 6 or R¹ Figure 7
is a derivation frour the principal current obtained by known means which it is
unnecessary to describe.

page_text: In the Figures 8, 9 and 10 I have represented different positions of the carbons.
Around one of the electrodes I arrange one or more solenoids concentrically with
respect to the electrode or electrodes or in any other position.
The solenoids have for their object to impress upon the arc a movement of rotation
centreing it consequently upon the axis of the magnetic field created by the solenoid.
In this manner the carbons are maintained of a constant and uniform shape.
Figure 8 shews a solenoid 3 concentric to the positive lower carbon i, its effect is
to insure the horizontal and central position of the crater.
Figure 9 shews a crater maintained in an oblique position. Finally Figure 10
shews two carbons which, in place of being arranged upon the same axial line form
an angle between them. This arrangement is rendered possible by the employment
of the solenoids.
I may also, in place of the solenoids employ permanent magnets or tubular electro
magnets for centreing the are.
In certain cases it is convenient to rotate the two carbons or one of the two only
upon their longitudinal axis so as to insure an absolute uniformity of figure. This
result may be obtained by means of any suitable mechanism.
The arrangement which I have described and particularly the automatic regulator
may be applied to lamps working with alternating current as well as to lamps with
continuous current.
I do not limit myself to the details of carrying out my invention as these may be
varied according to circumstances.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
1. A combination with an electric arc lamp. of an automatic regulator operated by
the heat of the luminous focus to maintain the said focus in a constant position.
2. The combination with an electric arc lamp of an automatic regulator operated by
the light produced at the luminous focus to maintain the said focus in à constant
position.
3. The automatic regulator as I have described and represented it consisting in the
combination of a screen with a metallic wire sensitive to light or to heat, the said
wire controlling the oscillations of a lever serving to establish or to break electric
contact.
4. The combination with the automatic regulator of the mechanical arrangements
above described and shewn in Figures 6 and 7 to operate upon the lower carbon of
the lamp.
5. In an arc lamp the combination with one or other of the electrodes or with both
the electrodes, of solenoids, magnets or tubular electro magnets arranged as I have
described and represented in Figures 8, 9, and 10 of the annexed drawings with the
object of increasing the stability of the voltaic arc.
Dated this 9th day of August 1890.
CARPMAEL & Co.,
Agents.