US2348825A

US2348825A - Electric lamp

Info

Publication number: US2348825A
Application number: US305883A
Authority: US
Inventors: Kratky Anton
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-11-24
Filing date: 1939-11-24
Publication date: 1944-05-16
Anticipated expiration: 1961-05-16

Description

2 sheeis-see't 1 INVENTOR 7 ATTORNEY A. KRATKY ELECTRIC LAMP Filed Nov. 24, 1939 May 16, 1944.

A. KRATKY ELECTRIC LAMP May 16, 1944.

Filed Nov. 24, 1959 2 Sheets-Sheet 2 INVENTOR gri/0n /rd//g BY; I

ATTORNEY Patented May 16, 1944 ELECTRIC LAMP Anton Kmky, vienna, Germany; vested in the Alien Property Custodian Application November 24, 1939, Serial No. 305,883 (Cl. 176-122) 3 Claims.

The present invention relates to electric lamps for illuminating or therapeutic purposes, the object being to provide a lamp wherein a metallic lament in liquid form during the operation of the lamp, constitutes the principal light source of the lamp or the principal source of radiant energy.

In the accompanying drawings Figure 1 is a sectional view of one illustrative embodiment of the invention in semi-diagrammatic form, and Figure 2 is a similar sectional view of another embodiment of the invention, the section of each view being through the vertical axis of the lamp and mounting.

Referring to Figure 1, a transparent lamp body i which may be generally conical in shape is provided with an annular groove 2 at the point of greatest diameter which, if the lamp is used in a vertical position, will coincide with the base of the lamp body. The bottom 3 of the lamp body is domed slightly and at one point in the groove 2 a barrier 4 may be formed as shown. The groove 2 is adapted to receive a body of a metal, or of an alloy of metals. which will be liquid at all times, or which will easily become liquid during operation of the lamp. For example, the groove may contain a body of mercury, sodium o`r potassium, or a suitable alloy of tlese or similar metals. In the further description of the invention it will be assumed that mercury is employed and that other suitable metals may be substituted therefor.

The lamp body may be provided with the usual threaded shell 5 attached to the transparent material of the lamp body by non-conducting cement 6 which also carries a terminal l to which one of the wires 8 of the lamp circuit is attached, the other wire 9 being attached to the shell 5. The two wires 8 and 9 may extend into the lamp body through a tube I0 lying along one wall of the lamp body and terminating near the groove 2, the said wires projecting through the end of this tube to form terminals 8' and 9' extending into the groove 2. If the barrier 4 is used the terminals 8' and 9' will be positioned as shown. one on each side of the barrier 4 where they dip into a body of mercury Il carried in this groove. Where the wires 8 and 9 pass through the end of the tube I0 they are sealed in the usual manner. In case the barrier 4 is omitted the terminals 8' and 9 should be arranged to dip into the mercury at substantially diametrically opposed points in the ring of mercury. If desired in connection with the arrangement shown in Figure 1, a high resistance wire l2 of tungsten or other suitable material may be placed in the groove and connected at its ends with the terminals 8 and 9 in order to fox-m a closed circuit as an auxiliary conductor.

The interior of the lamp body may be evacuated or may be lled with a reducing or neutral gas at relatively low pressure'. For this pressure hydrogen or nitrogen may be used and if it is desired to modify the color of the light neon, argon or crypton individually or in suitable combinations may be used.

Assuming that the, lamp is to be operated in the vertical position shown in Figure 1 and that a. suitable direct or alternating current is supplied through the wires 8 and 9, the mercury within the groove 2 will become very highly heated. When the temperature has been increased suiiiciently mercury will vaporize and mercury vapor will tend to ll the interior of the lamp body. The vaporization of mercury will diminish the supply of mercury in the groove 2, thus increasing the resistance in the lamp circuit. As the mass of liquid mercury decreases it will tend to divide itself into separate particles and a number of minute arcs may be formed between adjacent particles. The high resistance wire l2 when used will prevent the electrical circuit from becoming entirely broken.

In order to prevent undesirable fluctuations in the lamp circuit, should they occur, a line series resistance or ballast may be connected into the lamp circuit exteriorly of the lamp.

According to the present invention the liquid metallic lament is maintained or restored continuously by the condensation of the mercury vapor upon the conical sides of the lamp body and by returning the liquid mercury to the groove 2. Thus the supply of mercury n this groove is replenished and maintained so that the eleca trical circuit through the mercury is not completely interrupted.

As will later be described, means are provided to facilitate the condensation of mercury vapor by conducting heat away from the lamp body, particularly from the upper conical part. The cycle of operation consisting of the vaporization of the mercury and the condensation and return thereof to the groove, prevents the building up of unduly high pressure within the lamp body.

The lamp body may be of glass having a. melting point of about 1000 C., or quartz glass having a, melting point of about 1500 C., and in order to protect the material of the lamp body from the high temperature developed in the groove l2 this groove may be provided with a lining 2' oi' an oxide having a still higher melting point such, for example, as magnesio. or thorium oxide.

The means above referred to for cooling the upper part of the lamp body may consist of a conical shell I5 lying in close proximity to the walls of the lamp body and adapted to receive heat therefrom. This heat may be absorbed by a cooling fluid circulating within a chamber I6 and supplied thereto by a tube I1 and carried away by a tube I8 or may be radiated to the surrounding air by a number of fins I9 attached to the shell I5 or by both.

The shell I5 is conveniently formed as a part 'of or attached to a supporting member 20 in which an internally threaded socket 2i is mounted and separated from the supporting member by an insulating member 22, which in turn carries a contact member 23, the socket 2I and the contact member 23 constituting terminals for the lead wires 2I and 23', which when the lamp is in place connect respectively with the wires 9 and 8.

When in operation in a vertical position as shown in thedrawings, gravity may be relied upon to return the condensed mercury vapor to the groove 2, but if the lamp is to be operated in any other position or if it is not desired to rely entirely upon the force of gravity to return the condensed mercury to the groove 2, the entire lamp body and its mounting may be rotated so that centrifugal force will act to return the condensed mercury vapor rapidly to the groove 2 in the lamp body.

For this purpose the lamp mounting 20 may be carried upon a shaft journaled in a fixed member 26 and arranged for rotation in any suitable manner as by a motor M carrying a, pulf ley 21 which is connected by belt 28 with a belt groove 29 formed in the mounting 20.

In order to effect an electrical connection between the conductors of the rotatable mounting 20 and fixed memberV 26, the mounting 20 may lbe provided with commutator rings 30 and 3l against which

brushes

32 and 33 are arranged to bear. These brushes 32 and33 may be connected to a suitable source of electrical energy, either alternating or direct current at suitable potential, which may be 110 or 220 volts either direct or alternating current.

If it is desired to operate the lamp upon a three-phase alternating current a third lead, brush, commutator ring and lead-in wire may be provided in a readily understood manner, and

' in such case three terminals, instead of the two terminals, 8 and 9' as shown, will be positioned equidistant from each other in the groove 2 of the lamp body.

In order to supply a cooling uid to the cooling chamber I6 when the lamp housing is rotated, the tubes I1 and I8 may be extended through the shaft 25 and arranged to open into

channels

35 and 36 formed in the member `25, these channels being in turn connected through

passages

31 and 38 with a suitable source of cooling uid whichmay be caused to circulate through the cooling system in any suitable manner as by a pump or by gravity.

The radiant energy developed within lthe lamp body may be used alone or partly or entirely for the stimulation of a fluorescent coating which in turn will then produce desirable light rays. For this purpose the lamp body may be provided at much the same manner as the form of the insuitable places, for example, upon the outside of Y vention shown in Figure 1. except for the fact that the heating of the liquid metallic moment within the lamp body is eifected by an electrical current induced therein by a coil located in close proximity thereto.

Referring to Figure 2, a lamp body 40 generally frusto conical in shape, is provided and a circular groove or channel 4I4 formed at the lower and outer edge. An axial passage 42 may be provided through the lamp body for a mounting member 43 which, as shown, is adapted to be fastened tothe shaft of a motor M.

Means are provided adjacent the upper part of the lamp body for conducting away heat and may conveniently take the form of a metallic shell 44 provided with heat radiating ilns 45. The lamp may be held on the mounting member 43 in any convenient manner as by a nut 43 threaded on the mounting member 43 and the mounting member 43 may be suitably keyed or fastened to the shaft of the motor as by a set screw 41.

If it is desired to use this lamp in the vertical position as shown, the force of gravity may be relied upon to return the condensed mercury vapor to channel 4I, as previously explained in connection with Figure l, but if it is desired to augment gravity by centrifugal force or if the lamp is to be operated in any position other than the one shown, it may be rotated upon the shaft of the motor M.

The heating of the liquid metallic filament 5I within the groove 4I is effected according to well known principles by placing in close proximity to the lamp a coil 5I through which a suitable alternating current is passed to induce a current in the ring of mercury, or other suitable metal,

lying in the groove 4I within the lamp body 40. The coil 5I may be so designed and energized as to induce within the liquid metallic filament present invention it is possible to obtain veryhigh temperatures approaching 2900 C, instead of the maximum temperature hitherto possible in the neighborhood of 2200 C. Inasmuch as the light rays emitted do not, in accordance with well known laws, increase proportionately with the temperature but according to the fourth power of the temperature, very considerable economy and efficiency will be secured by lamps made according to the present invention. The utilization of metals in iilament of a lamp in accordance with the present invention, permits the heating of the lament to a point not hitherto attained. The degree of heat which may be imparted to solid metallic lilaliquid form as the l lamps ranging from 2000 to 2400" C. Where an.

electrical current is passed through vaporized metal less light will be generated than when the same current is passed through the same metal in a solid or liquid state. According to the present invention the metallic filament in liquid form may be heated above its vaporizing. temperature and maintained at a very high temperature because the vaporized /metal is continuously condensed and returned to its liquid form and again becomes a part of the electrical circuit.

The invention may be variously modied and embodied within the scope of the subjoined claims.

I claim:

1. An electric lamp having in combination a rotatably mounted closed evacuated transparent housing provided with a groove adjacent the outer edge thereof, a lament in said housing formed by an attenuated body of mercury and a high resistance wire located in said groove and immersed in the mercury, means for passing an electric current through said filament to vaporize said mercury, means for cooling a wall of said housing to condense said vapor thereon, 'and means for rotating said housing on an axis perpendicular to said groove to accelerate the flow of condensate along said wall back to said lament to replenish the same in a continuousY cycle.

2. An electric lamp having in combination, a closed evacuated transparent lamp body, aprimary electrical metallic conductor, liquid at ordinary temperatures, conned within an annular groove in said body, an auxiliary conductor whose terminals are immersed in said primary conductor, means for passing current through the auxiliary conductor to heat said primary conductor far above its boiling point and cause a plurality of arcs to pass between individual particles thereof in said groove, and cooling means located above said groove for condensing vapor of said primary conductor and said body having a wall extending from said cooling means to said groove for returning said condensed vapor to said groove to be reused.

3. An electric lamp having ln combination, a closed evacuated transparent lamp body, a primary electrical metallic conductor, liquid at ordinary temperatures, confined withinan annular groove in said body, an auxiliary conductor immersed in said primary conductor, means for passing current through the auxiliary conductor to heat said primary conductor far above its boiling point and cause a plurality of arcs to pass between individual particles thereof in said groove, and cooling means located above said groove for condensing vapor of said primary conductor and said body having a wall extending from said cooling means to said groove for returning said condensed vapor to said groove to'be reused.

ANTON