U.S. patent number 3,624,386 [Application Number 04/792,387] was granted by the patent office on 1971-11-30 for arc lamp.
This patent grant is currently assigned to The Strong Electric Corporation. Invention is credited to Harold M. Plumadore.
United States Patent |
3,624,386 |
Plumadore |
November 30, 1971 |
ARC LAMP
Abstract
The disclosure embraces an arc lamp construction utilizing a
lamp comprising a gas-filled envelope containing spaced electrodes
in combination with magnetic forces for controlling the arc flame,
and a mounting for the gas-filled lamp adjustable to control the
relative position of the arc with respect to a reflector.
Inventors: |
Plumadore; Harold M. (Toledo,
OH) |
Assignee: |
The Strong Electric Corporation
(Toledo, OH)
|
Family
ID: |
25156731 |
Appl.
No.: |
04/792,387 |
Filed: |
January 21, 1969 |
Current U.S.
Class: |
362/261 |
Current CPC
Class: |
G03B
21/2026 (20130101); F21V 19/02 (20130101); F21W
2131/406 (20130101); F21V 29/677 (20150115) |
Current International
Class: |
F21V
29/00 (20060101); F21V 29/02 (20060101); F21V
19/02 (20060101); F21S 8/00 (20060101); G03B
21/20 (20060101); F21v 019/02 () |
Field of
Search: |
;240/44.2,51.11R,11.4A,41A ;313/161 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Matthews; Samuel S.
Assistant Examiner: Moses; Richard L.
Claims
I claim:
1. In combination, a housing, a lamp in said housing comprising an
elongated sealed envelope containing an inert gas and electrodes
spaced to provide an arc by the passage of electric current between
the electrodes, a reflector arranged to project light from the arc,
lamp supporting means in the housing, said lamp supporting means
including means engaging the lamp adjustable lengthwise of the
housing for adjusting the position of the lamp lengthwise of the
axis of the electrodes, second adjustable means operatively
engaging the lamp for moving an end region of the lamp vertically
and transversely of the axis of the reflector, and a permanent
magnet spaced laterally of the arc between the electrodes, the
polarity of the magnet being arranged to influence the position of
the incandescent gases at the arc to effect a stabilization of the
incandescent gases at the region of arc substantially congruent
with the focal point of the reflector.
2. In combination, a housing, a lamp in said housing comprising an
elongated sealed envelope containing an inert gas and electrodes
spaced to provide an arc by the passage of electric current between
the electrodes, a reflector arranged to project light from the arc,
lamp supporting means in the housing, said lamp supporting means
including means engaging the lamp adjustable lengthwise of the
housing for adjusting the position of the lamp lengthwise of the
axis of the electrodes, second adjustable means operatively
engaging the lamp for moving an end region of the lamp vertically
and transversely of the axis of the reflector, a permanent magnet
spaced laterally of the arc between the electrodes, the polarity of
the magnet being arranged to influence the position of the
incandescent gases at the arc to effect a stabilization of the
incandescent gases at the region of arc substantially congruent
with the focal point of the reflector, and means supporting the
magnet for adjusting the magnet with respect to the region between
the tips of the electrodes.
3. An arc lamp construction comprising, in combination, a housing
including a base portion, an arc lamp in said housing comprising an
elongated sealed envelope containing an inert gas and electrodes
spaced to provide an arc by the passage of electric current between
the electrodes, a reflector, means mounting the reflector in the
housing, support means for the lamp, said support means including a
first member, rotatable means on the base portion supporting the
first member for adjusting said member longitudinally of the
housing, clamp means engaging the envelope of the lamp, said clamp
means being mounted for limited articulation with respect to said
first member, a second member movably mounted on the base portion
and engaging an end region of the lamp, first means for adjusting
said second member in a direction transversely of the housing,
second means for adjusting said second member in a substantially
vertical direction, and magnetic means spaced from the region of
the arc for influencing the position of the incandescent gases at
the region of the arc.
4. The combination according to claim 3 wherein the magnetic means
is a permanent magnet, and support means for the magnet for
adjusting the distance of the magnet from the region of the
arc.
5. The combination according to claim 3 including electromagnetic
means spaced from the arc for influencing the position of the
incandescent gases at the region of the arc.
6. The combination according to claim 3 including a control member
accessible exteriorly of the base portion for adjusting the
relative position of said first member, and second and third
control members accessible exteriorly of the base portion for
manipulating said first and second means for adjusting an end
region of the lamp in vertical and horizontal directions.
7. An arc lamp construction comprising, in combination, a housing
including a base portion, an arc lamp in said housing comprising an
elongated sealed envelope containing an inert gas and electrodes
spaced to provide an arc by the passage of electric current between
the electrodes, a reflector, means mounting the reflector in the
housing, means supporting the lamp in the housing with the
electrodes in a substantially horizontal position, said lamp
supporting means including a first member, rotatable means on the
base portion supporting the first member for adjusting said member
longitudinally of the housing, bracket means engaging the envelope
of the lamp, said bracket means being mounted for limited
articulation with respect to said first member, a second member
movably mounted on the base portion and engaging an end region of
the lamp, first means for adjusting said second member in a
direction transversely of the housing, second means for adjusting
said second member in a substantially vertical direction, and
magnetic means spaced from the region of the arc for influencing
the position of the incandescent gases at the region of the arc.
Description
Arc lamps of the type wherein an arc is established by current flow
through spaced carbon electrodes have been used extensively for
cinematography, television casting and illumination for theatrical
purposes. In such lamps the electrodes at the region of the arc are
unconfined and the light rays from the incandescent ionized gases
at the arc are projected from a reflector to a desired area. In
lamps of this character the electrodes are consumed comparatively
rapidly requiring frequent replacement. The constant consumption of
the electrodes results in deposition of oxide particles upon the
reflector requiring frequent cleaning of the reflector in order to
maintain efficient light projection.
Endeavors have been made to utilize a lamp of a character wherein
electrodes are confined in a transparent envelop filled with an
inert gas, such as xenon, the electrodes being spaced to provide an
arc source of light. Heretofore, if the xenon lamp were mounted
with the elongated lamp body in a horizontal position, the
incandescent gases or arc flame tend to be offset vertically
upwardly from the axis of the electrodes. Therefore present
practice is to mount the lamp with the axis of the electrodes in a
vertical position. Operation of the lamp in a vertical position
rendered it impossible to use an efficient form of optical system
in a light projector. Such lamp used in other than a vertical
position effected an overconcentration of heat at an adjacent
region of the transparent envelope, such as an envelope of quartz,
resulting in damage to the envelope.
The present invention embraces an arc lamp construction utilizing a
gas-filled electrode illuminating means for producing an arc
wherein the longitudinal axis of the lamp construction is disposed
in a substantially horizontal position in association with means
for confining the incandescent gases of the arc flame substantially
at the region between the adjacent extremities of the electrodes
whereby a high efficiency of illumination from the arc is
attained.
An object of the invention resides in an arc lamp arrangement
utilizing an elongated lamp construction wherein electrodes are
disposed in a sealed transparent envelope filled with an inert gas,
such as xenon, in combination with magnetic means disposed with
respect to the arc between the electrodes to stabilize and maintain
the arc flame centralized in the region between the electrodes
thereby eliminating concentration of heat from the arc at any
localized region of the confining envelope.
Another object of the invention resides in a mounting means for an
elongated type of gas-filled electrode arc lamp in a light
utilization apparatus, the mounting means providing for universal
adjustment of the lamp facilitating the accurate positioning of the
arc at the focal point of a reflector of the apparatus.
Another object of the invention is the provision of an arc lamp
construction embodying an arc source of light provided by current
flow between electrodes sealed in a gas-filled envelope wherein one
end region of the elongated lamp is pivotally supported and the
other end region rendered adjustable in vertical and transverse
directions for accurately positioning the region of the arc at a
focal point of the reflector, the arrangement including the
establishment of magnetic forces acting in a direction to confine
the flame of the arc to a centralized region at the adjacent
extremities of the electrodes.
Another object of the invention resides in an arc lamp construction
wherein an elongated xenon lamp is disposed substantially
horizontally in a lamp housing, and means for circulating air
through the housing to convey away heat developed by the arc and to
cool the current conductors at the ends of the xenon lamp.
Further objects and advantages are within the scope of this
invention such as relate to the arrangement, operation and function
of the related elements of the structure, to various details of
construction and to combinations of parts, elements per se, and to
economies of manufacture and numerous other features as will be
apparent from a consideration of the specification and drawing of a
form of the invention, which may be preferred, in which:
FIG. 1 is a side elevational view of an arc lamp light projecting
structure embodying a form of the invention;
FIG. 2 is a top plan view of the arc lamp structure shown in FIG.
1;
FIG. 3 is a vertical longitudinal sectional view taken
substantially on the line 3--3 of FIG. 2;
FIG. 4 is a longitudinal horizontal sectional view with the xenon
lamp removed, the view being taken substantially on the line 4--4
of FIG. 3;
FIG. 5 is an enlarged fragmentary detail view taken substantially
on the line 5--5 of FIG. 3;
FIG. 6 is an elevational view taken substantially on the line 6--6
of FIG. 3 illustrating one position of an arc flame control
means;
FIG. 7 is a fragmentary sectional view taken substantially on the
line 7--7 of FIG. 6;
FIG. 8 is a fragmentary view of a portion of the gas-filled lamp
illustrating the relative position of the arc flame stabilized
between the electrodes;
FIG. 9 is a view illustrating a modified position for the arc flame
control means;
FIG. 10 is a view similar to FIG. 7 illustrating a form of
electromagnetic means for controlling the arc flame, and
FIG. 11 is a view similar to FIG. 9 illustrating a modified
position for electromagnetic means for controlling the arc
flame.
While the invention is illustrated in a projection arc lamp
especially adapted for cinematography, television casting and
theatrical lighting, it is to be understood that the invention may
be used with other forms of lamp construction such as searchlights
and the like.
FIGS. 1 through 4 illustrate a projection lamp construction
embodying a form of the invention. The projection lamp construction
is inclusive of a housing 10 of substantially rectangular shape
elongated in the direction of light rays projected from a
reflector. The lamp structure has a base construction 12,
preferably of cast metal, which supports an upper portion or
section 14 of the housing fashioned of sheet metal. The sheet metal
portion 14 of the housing is fashioned at one side with an opening
normally closed by a movable door 16, the door being pivotally
supported by pivot pins mounted in lugs or bosses 18 provided on
the upper portion of the housing.
The upper portion of the housing 10 is equipped with a baffle or
member 20, particularly shown in FIG. 3, secured to the roof 21 of
the housing by means of brackets 22. The baffle 20 is fashioned
with a vent stack 24 through which air is vented from the housing
10 to convey away the heat from the arc lamp. Mounted upon a raised
portion 26 adjacent the rear portion of the base 12 is a pedestal
or support means 28 having forwardly extending projections 30 to
which is secured a reflector mounting means or supplemental frame
32 particularly shown in FIG. 3.
Supported upon the mounting means 32 is a reflector 35 preferably
of ellipsoidal shape adapted to reflect or project rays of light
from the arc forwardly through an opening in the front of the
housing 10. The reflector mounting frame 32 is equipped with
peripherally spaced spring clips 36 which engage the rear surface
of the reflector 35. The reflector is held in engagement with the
spring clips 36 by a latch member 37 pivotally supported on a lug
38, the latter carried by the reflector supporting frame 32. The
latch member 37 is illustrated in FIG. 3 in reflector retaining
position and is adapted for pivotal movement to facilitate removing
the reflector.
Light rays from the reflector 35 are projected through an opening
40 in the housing section 14 and through an opening 41 in a
supplemental housing 42 secured on the front panel of the housing
10. A douser screen or light impeding member 43 is secured to a
shaft 44 journaled in bosses 45 carried by the supplemental housing
42.
The shaft 44 extends exteriorly of the douser or supplemental
housing 42 and is equipped with a handle 46. The douser or light
impeding member 43 is shown in open position in FIG. 3 and is
manually movable about the axis of the shaft 44 for closing the
opening 41 to interrupt the projection of light.
The lamp 48 providing the arc source of light is of elongated
construction and includes enlarged end terminal regions 50 and 52,
the end construction 50 supporting a cathode electrode 54, the
enlarged portion 52 supporting an anode electrode 56, the tips or
extremities of the electrodes being spaced apart as shown in FIG. 3
to provide a gap 57 in which the arc is formed by electric current
flow between the electrodes. A current conductor 58 sealed in the
end region 50 is connected with the electrode 54 and with an
igniter 59 of conventional construction for initiating operation of
the lamp, the igniter being supported on the pedestal 28. A power
switch 61 controls current supply to the electrodes, and an igniter
switch 65 is provided for energizing the igniter 59 for striking
the arc between the electrodes.
Conductor 60 is sealed in the end region 52, and is connected with
the electrode 56 and with a power supply. The current supply is
preferably AC current rectified to direct current with a minimum
current ripple. The lamp is fashioned with an elongated transparent
envelope 62 fashioned of quartz of good optical quality, the
envelope having an intermediate spherically shaped portion 64
adjacent the arc which is formed between the tips of the
electrodes.
The envelope 62 is filled with an inert gas under pressure, such as
xenon. The focal point of the reflector 35 is at the gap 57 on the
horizontal axis of the electrodes. The lamp 48 is adjustable so
that the arc may be adjusted to the most efficient light projecting
position with respect to the reflector 35 whereby maximum
illumination efficiency may be attained.
Referring particularly to FIGS. 3 and 4, the base structure 12 is
fashioned with boss portions 66 and 67. Each of the bosses is bored
to provide a journal support for a rotatable shaft 69. Rotatably
mounted on the front sidewall of the base 12 is a knurled knob 70
which is connected with one end of the shaft 69 by a flexible cable
72 of conventional construction of a character for transmitting
rotation of the knob 70 to the shaft 69. A pedestal or member 74
provides a support for one end region of the xenon lamp
construction 48.
The pedestal 74 is fashioned with a boss 76 which is bored to
accommodate the shaft 69, the pedestal 74 being slidable along the
shaft. The pedestal 74 is fashioned with a second boss 78 having a
threaded bore accommodating a threaded portion 79 of the shaft 69
which is threaded into the threaded bore in the boss 78. Through
this arrangement, rotation of the knob 70 effects rotation of the
shaft 69 through the flexible cable 72 for adjusting the lamp
supporting pedestal or member 74 lengthwise of the housing 14, the
direction of adjustment being dependent upon the direction of
rotation of the central knob or member 70.
The member 74 is fashioned with a bifurcated projection 81 which
straddles a pin 82 threaded into a bore in a projection 83
integrally formed on the base member 12. The pin 82 is locked to
the projection 83 by a locknut 84. The pin 82 extending between the
furcations of the bifurcated portion 81 is of a diameter to
facilitate sliding movement of the member 74 relative to the pin
82. The pin 82 serves to maintain the member 74 for adjustment in a
rectilinear direction lengthwise of the housing without pivotal
movement of the member 74.
The pedestal or member 74 is fashioned with an upwardly extending
web portion 86 which, as shown in FIG. 5, is fashioned at its upper
end with an opening 88 having chamfered entrance regions 90. A lamp
mounting bracket 92 has a bifurcated portion, the furcations 94
straddling the upper portion of the web 86. The furcations 94 are
respectively fashioned with a smooth bore and a threaded bore to
accommodate a bolt 96 which extends through the opening 88 in the
web 86 to mount the bracket 92 on the web 86 of member 74.
The web portion between the furcations 94 is of a thickness or
dimension to accommodate limited relative swivel movement of the
bracket 92 with respect to the web 86 to facilitate adjusting
movement of the other end region of the lamp. The lamp support
bracket 92 has a semicylindrical recess or cradle 98 which receives
an elongated cylindrical portion 63 of the xenon lamp envelope
62.
The portion 63 is embraced by a clamp member 100 which may be drawn
into snug engagement with the lamp portion 63 by screws 101.
Through this arrangement, the lamp may be adjusted lengthwise along
the axis of the reflector 35.
Means is provided engageable with the other end region of the xenon
lamp 48 for adjusting the said end region vertically and
transversely of the axis of the reflector to secure accurate
positioning of the arc in the space 57 with respect to the light
projecting surface of the reflector 35, this arrangement being
shown particularly in FIGS. 3 and 4.
The pedestal or member 28 at the rear of the reflector is fashioned
with a boss 104 and a second boss 106 spaced transversely from the
first boss as shown in FIG. 4. The boss 104 is bored to journally
support a shaft 108. The boss 106 is provided with a threaded bore
to receive a threaded tenon 109 of the shaft 108. Journally
supported upon means carried by the base structure 12 at the front
side thereof is a rotatable knob or member 110. A flexible cable
112 has one end secured to the rotatable knob 110 and the other end
secured to an end of the shaft 108.
A movable carriage 114 is mounted upon the shaft 108. The carriage
114 is fashioned with a first projection or boss portion 116 having
a bore therein receiving the shaft 108, the bore being slightly
larger than the diameter of the shaft to accommodate slidable
movement of the carriage along the shaft.
The carriage 114 is fashioned with a second projection or boss
portion 118 provided with a threaded bore accommodating the
threaded tenon 109 on the shaft 108. The carriage 114 is equipped
with a member or block 120 having a generally V-shaped notch 122
for receiving and supporting an end region of the xenon lamp
construction 48.
As shown in FIG. 3, the enlarged region 50 of the lamp construction
is nested or cradled in the V-shaped notch 122 provided in the
block or member 120. A rotatable control knob 126 is journaled by
means supported by the base structure 12. The pedestal 28 is
fashioned with a horizontally extending projection 128 having a
vertically arranged threaded bore accommodating a threaded stub
shaft 130. The movable carriage 114 is fashioned with a horizontal
pad or projection 132 which is engaged by the upper end of the
threaded stub shaft 130, as shown in FIG. 3.
One end of a flexible cable 134 is connected with the control knob
126, and the other end of the cable 134 fixedly secured to the
lower end of the threaded stub shaft 130. As will be apparent from
FIG. 3, rotation of the stub shaft 130, having threaded connection
with the projection 128, elevates or lowers the end region of the
lamp construction 48 depending upon the direction of rotation of
the stub shaft 130.
Rotation of the control knob 110 is transmitted by the flexible
cable 112 to rotate the shaft 108, rotation of the shaft 108 moving
or adjusting the carrier 114 in a transverse direction depending
upon the direction of rotation of the knob 110.
As the end region 50 of the xenon lamp 48 is nested in the notch or
cradle 122 of member or block 120, this end region of the lamp 48
will be moved transversely causing slight pivotal movement of the
lamp construction 48 about a vertical axis through the opening 88
in the web 86 accommodating the screw 96 so that the tips of the
electrodes 54 and 56 are adjusted transversely of the longitudinal
axis of the reflector 35 to effect transverse adjustment of the
arc.
Manual rotation of the control knob 126 is transmitted through the
flexible cable 134 to the vertically disposed threaded stub shaft
130. As the upper end of the stub shaft engages the pad 132 on the
carriage 114, the adjustment end region 50 of the lamp construction
48 will be elevated or lowered depending upon the direction of
rotation of the knob 126 and the stub shaft 130. Through this
arrangement the lamp construction 48 is pivotally moved in a
vertical plane about the horizontal axis of the screw 96 whereby
the tips of the electrodes 54 and 56 may be adjusted vertically
whereby the position of the arc may be vertically adjusted with
respect to the axis of the light-reflecting surface of the
reflector 35.
Heretofore it has not been practicable to utilize a xenon lamp in a
substantially horizontal position for several reasons. The body of
incandescent ionized gases of the arc is normally distorted
upwardly by the intense heat in the region of the arc causing a
concentration of heat at a localized region of the quartz envelope
above the arc.
This thermal instability sets up or establishes severe stresses in
the quartz envelope which weaken the lamp structure and as
comparatively high pressure exists within the quartz envelope, the
envelope is liable to be fractured by the effects of the localized
heating and internal pressures.
Due to the vertical distortion of the body of incandescent ionized
gases providing the light source, the light transmitted to the
reflector does not emanate from a comparatively small focal area
but from the large area of the distorted body of incandescent gases
between the electrodes. This condition results in very inefficient
diffused reflected light and impairs the control of light rays
projected from the reflector.
In the arrangement of the invention means is provided exerting
forces on the ionized body of incandescent gases of the arc for
eliminating the vertical distortion or distention of the gases and
stabilizing incandescent gases in a sphere or ball-like body
centrally disposed between the tips of the electrodes. Magnetic
forces are employed for performing this function. Referring
particularly to FIGS. 3, 4, 6 and 7, one form of means for
establishing magnetic forces is illustrated and includes an
L-shaped bracket 136 secured to the base portion 137 of the base 12
by screws 138.
Secured to an upwardly extending portion 139 of the bracket 136 is
a magnet support means or block 140. The upwardly extending portion
139 of bracket 136 is fashioned with a vertical slot 142 which
accommodates securing screws 143 extending into threaded openings
in the block 140.
The block 140 is fashioned with a bore to accommodate a bar magnet
146 of the permanent magnet type such as an Alnico magnet held in
position by a setscrew 141. The block is bored to position the bar
magnet 146 with its longitudinal axis disposed transversely of the
longitudinal axis of the lamp 48 and transversely of the housing as
illustrated in FIGS. 4 and 6.
As shown in FIG. 3, the bar magnet 146 is disposed with its central
region substantially vertically beneath the region of the arc
established between the tips of the electrodes. In reference to the
position of the magnet in respect of polarity the south pole or
negative pole end 148 is disposed at the left side of a vertical
plane A--A through the longitudinal axis of the lamp 48 and the
axis of the reflector 35 viewed from the front of the reflector as
illustrated in FIG. 6.
The north pole end or positive pole 150 of the bar magnet is
disposed an equal distance to the right side of the plane A--A as
viewed in FIG. 6. For most efficient action of the magnetic forces
on the body of incandescent gases it is preferable the central
position of the magnet be on the plane A--A, although effective
results may be attained if the bar magnet 146 is disposed a slight
distance in either transverse direction from the central position
illustrated in FIGS. 4 and 6.
It is found that by positioning the magnet means 146 in the
position described with respect to the body of incandescent gases
providing the arc light, the body of incandescent gases is drawn
downwardly by magnetic forces so that the central region of the
body of the incandescent gases is substantially at the axis of the
electrodes and that the body of incandescent gases becomes
substantially spherical with a minimum of distortion. By
stabilizing the body of incandescent gases centrally between the
electrodes, there is no concentration of heat at a localized region
of the spherical portion 64 of the quartz envelope so that
localized thermal stresses are eliminated.
The concentration of the body of incandescent gases into a smaller
comparatively spherically shaped volume more nearly approaches a
point source of light at the focal point of the reflector so that
the rays of light projected from the reflector are better
controlled and may be concentrated in a smaller area for
illumination purposes. It is also found that by stabilizing the
incandescent gases between the electrodes in a spherically shaped
body that improved efficiency of light rays are directed to the
reflector with an increased intensity in the usable light projected
from the reflector. It is also found that the concentration and
stabilization of the incandescent body of gases on the central axis
of the electrodes improves the light intensity to an extent that
the current supplied to the arc may be reduced and still provide an
amount of light directed to the reflector to secure efficient
projected light.
FIG. 8 is illustrative of the effect of the magnetic forces in
stabilizing the body of incandescent gases between the electrodes.
The relative position and general shape of the distorted body of
incandescent gases without the stabilizing effect of the magnetic
forces is indicated in broken lines at 152. In this position the
incandescent gases are normally distorted upwardly to a position
wherein the region of the spherically shaped portion of the quartz
envelope above the distorted body of gases is subjected to a
concentration of heat from the gases.
With the use of the bar magnet 146 positioned as shown in FIG. 6,
the body of incandescent gases is indicated at 154 in full lines
where it will be seen that the body of incandescent gases is more
nearly spherical in shape with its center substantially on the axis
of the electrodes and at the focal point of the reflector.
The effect of the magnetic forces provided by the magnetic means
146 may be varied by adjusting the relative position of the bar
magnet 146 vertically and thereby make possible the most efficient
stabilized position of the body of incandescent gases for efficient
illumination from the reflector.
The size of the bar magnet 146 and its relative position with
respect to the arc vary with the amount of current producing the
arc and the strength of the magnetic forces. As an example in
utilizing an xenon lamp of 6 kilowatts, a bar magnet 146 of about 1
inch in diameter is disposed with its axis approximately 7 inches
below the longitudinal axis of the lamp, the length of the magnet
bar being between 4 and 5 inches.
It is further found that the spacing between the tips of the
electrodes 54 and 56 may vary between 3 millimeters and 12
millimeters depending upon the capacity of the lamp and the size
and focal length of the reflector 35 with which the lamp is used.
It has been found preferable to utilize a spacing for the
electrodes to minimize the volume of incandescent gases in the arc
and yet secure efficient light projected from the reflector by
reducing the volume of the body of incandescent gases providing the
arc.
The light source provided by the stabilized arc more nearly
approaches a point providing for better control of light rays from
the reflector as well as to promote a reduction in the amount of
current for establishing the arc. While the bar magnet illustrated
has end surfaces in converging angular planes, it is to be
understood that a bar magnet having its end surfaces in
substantially parallel planes may be used if desired.
FIG. 9 illustrates a modified positioning for the bar magnet. As
shown in FIG. 9, a bracket 136a is secured to the baffle member 20
or to other support means. The bar magnet 146a is mounted in a
block 140a which is adjustably secured to the bracket 136a by bolts
143a. The magnet 146a is disposed adjacent the upper terminus of
the reflector with the axis of the bar magnet 146a in a transverse
vertical plane passing through the arc established in the space 57
between the tips of the electrodes.
In this form, the bar magnet 146a is positioned whereby the north
or positive pole end is disposed at the left side of the plane A--A
shown in FIG. 6 viewed from the front of the reflector 35. With the
bar magnet 146a in such position, the magnetic forces repel the
normally upwardly distorted body of incandescent gases, forcing
them downwardly to stabilize the body of incandescent gases more
nearly centrally on the axis of the electrodes.
Such magnetic forces eliminate the distortion of the arc flame or
incandescent gases and provide a more nearly spherically shaped
body of incandescent gases, thus improving the efficiency of light
projected from the reflector and eliminating concentration of heat
in a localized area of the spherical portion 64 of the quartz
envelope above the body of gases.
FIG. 10 is a view similar to FIG. 7 illustrating an electromagnetic
means for stabilizing the incandescent gases of the arc. The
arrangement illustrated in FIG. 10 includes a bracket 136b secured
to portion 137 of the base structure 12 of the lamp. A block 140b,
adjustable relative to the bracket 136b, is secured in adjusted
position by bolts 143b. In this form, the magnetic means is
inclusive of a soft iron core 156 surrounded by a coil 158 having
leads or conductors 160 and 161 for connection with a current
supply, preferably of low voltage.
The electromagnetic means 156, 158 is disposed in a bore in the
block 146b, the coil 158 being insulated from the core 156 and from
the block 140b. The current flow through the coil is in a direction
to establish the south or negative pole end of the core 156 to the
right side of the plane A--A, shown in FIG. 6, viewed from the
front of the reflector, whereby the electromagnetic forces are
effective to eliminate the upward distortion of the body of
incandescent gases providing the arc as illustrated at 152 in FIG.
8 to stabilize the body of gases in more spherical form centrally
between the tips of the electrodes, as illustrated at 154 in FIG.
8.
With the use of an electromagnetic means illustrated in FIG. 10,
the stabilization of the body of incandescent gases may be
accurately controlled by varying the voltage or amperage of the
current flow through the coil 158. The coil 158 is connected with a
supply of direct current.
FIG. 11 is a view similar to FIG. 9 illustrating an electromagnetic
means disposed above the arc produced between the electrodes and on
an axis in a transverse vertical plane passing through the gap or
space 57 between the electrodes. The bracket 136c carried by the
member 20 supports a block 140c secured to member 136c by bolts
143c. Disposed in the bore in the block 140c is an electromagnetic
means comprising a soft iron core 156c and a coil 158c surrounding
the core, the coil being insulated from the core 156c and from the
block 140c and provided with conductors or leads 160c and 161c, for
connection with a direct current supply.
With the electromagnetic means 156c, 158c in the position shown in
FIG. 11 adjacent the upper terminus of the reflector 35, the
current flow through the coil 158c is in a direction opposite to
the current flow through the coil 158, shown in FIG. 10. With
current flow in the opposite direction, the polarity of the soft
iron core 156c is reversed whereby the electromagnetic forces act
on the upwardly distorted incandescent gases of the arc to force
the gases downwardly whereby the incandescent body of gases is more
nearly spherical as illustrated at 154 in FIG. 8 with the center of
the body of gases substantially on the axis of the electrodes.
The amperage or voltage of the current flow through the coil 158c
may be varied to vary the intensity of the magnetic forces provided
by the electromagnetic means to accurately control the position of
the body of gases of the arc between the electrodes so as to obtain
maximum efficiency of projected light from the reflector 35.
The lamp housing 10 is provided with means for effectively
conveying away the heat developed by the arc. Disposed in the
housing portion 14 is a blower 165 driven by a motor 166. Air is
admitted to the blower through an opening 168 of an annular fitting
169 mounted on the upper panel 21 of the housing structure 14. Air
entering the opening 168 is conveyed to the axial region of the
blower 165 through a flexible tube 170. The tangential outlet
portion 172 of the blower is connected by a duct 174 with the
hollow interior region 175 of the base structure 12.
The air from the duct 174 flows through an opening in a web 177 of
the base structure and through a duct 178 to deliver air onto the
end region 52 of the xenon lamp construction. The angularly
disposed portion 180 of the base structure is fashioned with
openings (not shown) to facilitate flow of air through openings 182
in the reflector support frame 32 and through openings 184 in the
base structure to facilitate cooling of components in the rear
region of the lamp housing 10. The air delivered by the blower 165
is vented through the stack 24 to the atmosphere.
While the most efficient stabilizing effect of the magnetic means
is attained with the magnet positioned either directly below or
above the region of the arc, it is to be understood that the
magnetic means may be slightly out of a vertical position through
the arc and secure effective stabilization of the body of
incandescent gases. The universal adjusting means for the xenon
lamp 48 hereinbefore described provides an efficient and effective
means for accurately positioning the arc between the electrodes at
the focal point of the reflector 35.
It will be seen that through the universal adjustment for the xenon
lamp and the utilization of the stabilizing forces of magnetic
means for controlling the relative position of the body of
incandescent gases at the arc, a most efficient utilization and
projection of light from the arc is attained.
Furthermore, in utilizing an arc provided in a gas sealed envelope
there is no residue deposited upon the reflector surface such as is
encountered in the use of an unconfined arc provided between carbon
electrodes.
It is apparent that, within the scope of the invention,
modifications and different arrangements may be made other than as
herein disclosed, and the present disclosure is illustrative
merely, the invention comprehending all variations thereof.
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