US2105430A

US2105430A - Electric lamp

Info

Publication number: US2105430A
Application number: US393421A
Authority: US
Inventors: Herbert E Metcalf
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1929-09-18
Filing date: 1929-09-18
Publication date: 1938-01-11
Anticipated expiration: 1955-01-11

Description

.Jan. 11, 1938' H. E METCALF 2,105,430

ELECTRIC LAMP Original Fil ed Sept. 18, 1929 2 Sheets-Sheet l IE'lE l II. .II

ll 24 ll ATTO Jan. 11, 1938. H. E. METCALF ELECTRIC LAMP Original Fi led Sept. 18, 1929 2 Sheets-Sheet 2 INVENTOR.

Patented Jan. 11,1938

UNITED STATES PATENT OFFICE ELECTRIC LAMP York Application September 1:, 1929, Serial No. 393,4:1

. Renewed June 25, 1936 'lOla-ims.

This, invention relates generally to the construction of electric lamps utilized for illuminating purposes, and which employ light sources such as metallic filaments heated to mean-- 5 descence by means of an electric current. The

invention is of particular value where it is desired to produce a source of illumination of high candle power, as for example in the taking of motion pictures,'or for motion picture proiection work. It will be obvious that the invention is applicable to electric lamps in general which have light sources of high heat intensity.

Inthepast,ithasbeencommontoutilize' metallic filament electric lamps of relatively high wattage consumption for the production of a light source of relatively high candle power. By lamps of high wattage consumption, I have particular reference to lamps consuming one kilo-- watt or more of electrical energy. Because of an dimensions of the filaments and the relatively high temperatures at which they are operated,

it has been necessary in such lamps to utilize relatively largeevacuated envelopes. Even with such construction, while mechanical failure of as the evacuated envelopes may be avoided, the walls of the lamp are heated to a relatively high temperature and dissipatethls heat to convection currents of air and by radiation. imparting heat to convection currents of air surrounding a the lamp is frequently a serious objection, as for example when employing the lamp in a motion I picture projection room or in a soundproof motion picture recording studio. Furthermore, the light spectrum from such lamps contains a relatively high percentage of heat rays, which are frequently objectionable. Thus when using'such a lamp in a motion picture projection machine, a fire haurd iscreated in that the nature of the light is apt to heat inflammable film to cause a combustion, Furthermore, it is commonly appreciated that lamps of this character have a relatively short and uncertain life, largely because of the high temperature to which the parts of the lamp are heated.

as It is an object of the present invention to devise an electric lamp having a light source which can produce a high deg'reeof illumination,

without imparting an objectionable amount of heat to the air of the room or enclosure in which so the lampi s being operated.

It is a further object of this-invention to devise a lamp which will produce substantially cold light, that is, a light having a relatively low percentage of heat rays.

5 {It is a further obiectof invention to devise a lamp of the above character which will be relatively compact, and which will have a relatively long life.

Further objects of the invention will appear from the following description in which the pre- 5 ferred embodiments of the invention have been set. forth'in detail. It is to be understood that the appended claims are to be accorded a range of equivalentsconsistent with the state of the prior 10 art.

Referring to the drawings:

Figure 1 is a side elevational view, partly-in cross section, illustrating an electric lamp incorporating the invention.

Fig. 2 is a cross sectional view, taken along the line 2-2 of Fig.1.

Fig. 8 is a circuit diagram illustrating the manner in which-I prefer to interrelate the circuit for energizing my lamp, with the source of cooling fluid.

Pig. 4 is a side elevational view,'partly in cross section, illustrating a modified form of electric lamp incorporating my invention.

Fig. 5 is a cross sectional view taken along the line l-lof Fig. 4. 1

Fig. 6 is a side elevational view partly in cross section, illustrating a further modified form of my invention.

Referring first to l igsai and 2 for a detailed description of one specific embodiment of my insovention, I have shown a metallic filament ll -made of some suitable metal. such as tungsten,

positioned within an envelope I! of light transmitting material, such as glass. 'Hiis envelope is evacuated or contains an inert gas so as to serve to protect the-filament from deterioration. For operably supporting the filament, there are shown members II and ll of insulating material, which are connected by the metallic spacing rods ll. 'lhelowerendsofrodsiiareshowng projecting through insulating member I and are welded or otherwise suitably connected to metallic members ll. Envelope i2 is shown formed with the usual reentrant tube ll, having 'apressliatitsinnerend. Rodsorbarsliare 4,5 ll

connected to members l1, and are suitably sealed in press is. Filament ll has been shown in the form of a coiled wire having its terminals connected to metallic rods i8, and looped a plurality of timesbetween support members II and M. The ends of the looped portions can be connected to members it and it by members 22. The lower end of envelope i2 is shown mounted 1 upon a conventional base 24, provided with contact prongs Ilfand which is. adapted to 00- operate with a. conventional lamp socket. Suitable electrical conductors connect prongs 26 with rods 2|. While the filament may take various forms, I prefer for projection work, that it be disposed substantially in a common plane as shown in Fig. 2.

Surrounding the envelope I2, I provide another outer envelope 21 which is preferably spaced from the inner envelope I2, at least for that portion of the inner envelope which immediately surrounds filament II. Envelope 21 is also made of some light transmitting material such as glass. The lower end of envelope 21 is sealed with respect to the inner envelope I2, as indicated at 28. The spacing between envelopes I2 and 21 forms a fluid chamber 29.

Chamber 29 is for the purpose of surrounding or encompassing the inner envelope I2 with a suitable cooling fluid preferably a liquid such as water. This cooling liquid is circulated through the chamber 29, preferably in such a manner that currents are formed to cause the liquid to swirl about the envelope I2. For this purpose, there is shown a tube 3| connected to the lower portion of outer envelope 21, and arranged to discharge liquid into chamber 29 in a tangential direction as shown in Fig. 2. Liquid is removed from the upper portion of chamber 29, as by means of the tube 32. It is apparent that because of the tangential relationship of inflow tube 3|, liquid introduced into chamber 29 will swirl about envelope I2 as it advances upwardly within chamber 29, and will finally be discharged through outflow tube 32. The imparting of a swirling movement to the cooling liquid insures adequate and uniform cooling of the envelope I2. Removal of liquid from the upper part of chamber 29 prevents the collecting of gas or air within the chamber. This gas is dissolved in the cooling fluid and is released in the form of bubbles on i the outer surface of the inner envelope I2 by the heat of the filament. The rapid swirling of the liquid sweeps away the bubbles before they become large enough to obstruct light, and would cause a gas or air pocket at the top of the chamber if not immediately removed by the outflow tube.

In operating the lamp described above, the filament is connected to a suitable source of electrical energy, and inflow pipe 3| is connected to a source of liquid under pressure, such as a water supply pipe. Assuming a. relatively high wattage consumption for the filament, say from 1 to 25 kilowatts or more, a large amount of heat will be imparted to the walls of the inner envelope I2, but this envelope will be kept at a relatively low temperature, since the heat is immediately con ducted to the liquid within the chamber 29. Likewise, the outer envelope 21 will be kept at a relatively low temperature, substantially the same as the temperature of water flowing through chamber 29, so that it will not heat air within the room or enclosure in which the lamp is operating. The water within chamber 29 also serves as a light filter medium to absorb a substantial amount of heat rays from the light radiated from the filament II. Thus, the light generated by the lamp is relatively cold, as is evidenced by the fact that when my lamp is utilized in a motion picture projection machine, an inflammable motion picture film may be stopped for an indefinite period without causing the film to .be ignited.

In Fig. 3, I have represented a special electrical circuit arrangement which will preclude injury to the lamp in the event of failure of the supply of cooling liquid. In this view, the lamp of my invention has been indicated generally as 34, and has its contacts 26 connected to the current supply lines I and 2. Connected in series with contacts 26, Iprovide a pair of cooperating

contacts

36 and 31. Contact 31 is carried by a flexible diaphragm 36, which in turn forms one wall of a liquid pressure chamber 39. Pipe 4| is connected to a source of liquid under pressure, such as a water supply pipe, and is in communication with chamber 39 thru a restricted nozzle or orifice 42. The object of orifice 42 is to discharge the liquid against diaphragm 36 with considerable kinetic energy thus causing this diaphragm to normally retain

contacts

36 and 31 closed. Discharge pipe 43 is connected with chamber 39, and in turn is connected to tube 3| of lamp 34, through a hose or pipe connection 44. When the lamp is in normal operation, continual introduction of liquid through pipe 4| retains

contacts

36 and 31 closed. However, in the event of the failure of the source of liquid supply, diaphragm 38 moves sufficiently to open

contacts

36 and 31, thus disrupting the supply of current to the lamp filament.

A modified form of my invention is shown in Figs. 4 and 5, in which the inflow and outflow tubes to the outer envelope project through a portion of the lamp base. Thus, in this instance, the lamp base I24 includes an annular collar 46, within which the lower end of envelope I21 extends. Suitable moldable material or cement 41, serves to secure and seal envelope I21 with respect to the base, and also with respect to the lower portion of the inner envelope II2. Envelope II 2 is likewise shown secured to and sealed with respect to the base, by means of moldable material or cement 48. Inflow pipe I3I, which in this instance is preferably made of metal, extends through a portion of the base, as for example thru the collar 46. The inner end portion of this tube I3I, is preferably directed in a tangential direction, as shown in Fig. 5.

The outflow pipe I32 is likewise preferably made of metal, and is also shown extended through the collar 46. The inner end portion 52 of tube I32 is shown extending upwardly between envelopes H2 and I21, and communicates with the upper portion of chamber I29, as shown in Fig. 4. Tube 52 is preferably flattened as shown in Fig. 5, in order to prevent objectionable restriction of the chamber I29.

A further modified form of my lamp is shown in Fig. 6 which is of particular value for substitution in place of the carbon electrodes of an arc lamp. In this instance, the terminals of the filaments are taken out through reentrance tubes 2I8, located at both ends of the inner envelope 2|2. Suitable bases 224 are mounted on the ends of envelope 2|2, and carry the contact members 56. These contact members are formed so that they can be operably engaged by the clamps normally used for holding arc electrodes. The outer envelope 221 in this instance has each end sealed with respect to collars 246, in the manner explained with respect to Figs. 4 and 5, and these collars are in turn formed as a part of the base structures 224. Liquid inflow tube 23| extends laterally through collars 246 and has a tangentially directed portion 25I, as shown in Fig. 4. Outflow tube 232 is at the upper end of the lamp, and extends laterally through the corresponding collar 246. The inner endportion 252 01 pipe 232, communicates with the upper portion of chamber229. The operation of the lamp shown in Fig. 6 as well as the lamp shown in Figs. 4 and 5, is substantially the same as the lamp described with respect to Figs. 1 and 2.

By utilizing the principles of my invention, it is possible to manufacture a commercial lamp for current consumption as high as kilowatts or more. Such lamps are comparatively compact, they give a cold light, and dissipate practically no heat to the surrounding air. For example, one lamp which I have constructed utilizes about three kilowatts, and is only approximately 3 inches in diameter. When used in a confined room or space, they cause practically no increase in the temperature of the surrounding air.

1. A liquid cooled lamp comprising a light source, a pair of concentric cylindrical transparent envelopes disposed around said source and spaced to form a chamber therebetween, an inlet conduit opening tangentially into one end of said chamber, and a transparent outlet conduit entering the same end of said chamber and extending through said chamber to open at the other end thereof.

2. A liquid cooled lamp comprising a light source, a pairof concentric cylindrical transparent envelopes disposed around said source and spaced to form a chamber therebetween, an inlet conduit opening tangentially into one end of said chamber, and a transparent outlet conduit entering the same end of, said chamber and extending through said chamber to open at the other end thereof, said outlet conduit being flattened within said chamber to reduce obstruction to rotational flow of liquid therein.

3. In combination, a cylindrical inner envelope, a light source mounted on one end thereof with energizing leads sealed therethrough, a cupshaped base having a rim adapted to receive the end of said envelope, said base also having a laterbase to seal said chamber, and inlet and outlet conduits entering said chamber through said base and said cement.

4. In combination, a vertically disposed, sealed, cylindrical inner envelope having a light source mounted therein, a cylindrical outer envelope disposed about said inner envelope in axial alinement therewith and sealed to said inner envelope to provide an annular chamber about the major portion of the surface of said inner envel pe. an

inlet conduit entering said chamber at one end thereof in axial parallelism with said envelopes and provided within said chamber with an arcuately directed portion lying transverseto the axis of said envelopes, and an outlet conduit entering said chamber adjacent said inlet conduit and parallel with a portion thereof, said outlet conduit extending longitudinally of said chamber and terminating at a point adjacent the axis of said envelopes.

5. In combination, a sealed cylindrical envelope having a light source mounted therein and energizing leads for said light source sealed through opposite ends thereof, a cup-shaped base having a flange thereon for engaging said envelope, disposed at each end of said envelope, n. cylindrical memberdisposed about said envelope, an annular flange on each of said bases for engaging an end of said cylindrical member, a quantity of cement in-each base for sealing said flanges to said envelope and said cylindrical member to provide a fluid-tight annular chamber about said envelope, a fluid conduit passing through each of said bases and said cement thereof and opening into said chamber at opposite ends thereof, and a connection stud on each of said bases and connected with said energizing leads, said studs be- .ing disposed in axial alinement with each other.

wherein the outlet conduit is of flattened section within the chamber to reduce obstruction to rotational flow of liquid therein.

HERBERT E. mm.