US2007931A - Multiple solid energy emitter - Google Patents

Description

C. H. BRASELTON MULTIPLE SOLID ENERGY EMITTER July 9, 1935.

Filed Au 19, 1930 2 Sheets-Sheet l l NVENTOR July 9, 1935. c. H. BRASELTQN 2,07,931

MULTIPLE SOLID ENERGY EMITTER Filed Aug. 19, 1950 2 Sheets-Sheet 2 I NVENTQR Patented July 9, 1935 2,007,931

UNITED STATES PATENT OFFICE MULTIPLE SOLID ENERGY EMITTER Chester H. Braselton, New York, N. Y2, assignor to Sirian Lamp Company, Newark, N. J a cornotation of Delaware Application August 19, 1930, Serial No. 476,342

6 Claims. (Cl, 176-1) This invention relates to energy radiating apcium, or other materials preferably of low electron paratus, and particularly to that type of apparaevaporation constants which have been found to tus which utilizes an ionized gaseous atmosphere, emit electrons densely when heated. The base inconjunction with an electric conductor. filament is preferably tungsten wire, although One of the objects of the present invention is other metal conductors may be used. It is not 5 to provide an energy radiating device which emnecessary that the base material be highly reploys as an element of the radiator, a material fractory as the operating temperatures are relawhich emits energy selectively, when heated. tively low, in many cases not being above that of Another object is to provide a radiator combinlow red heat. Ihe filament is preferably coiled ing a selective emitter and a heating unit, which and coated with materials as above mentioned, 10 heating unit also functions as a radiator. which may be initially in the proportions of 40 Still another object of the invention is to utigrams of barium carbonate, 40 grams of calcium lize, as far as possible, the total energy output carbonate, 8 grams of barium nitrate with a of a radiator of the type employing a metallic binder of sufiicient nitrocellulose dissolved in conductor in an ionizable gas, which gas is actiamyl acetate to hold the coating on the wire, 15 mind by ionization in a region adjacent the conand mounted on a stem support sealed in the ductor. Further objects of the invention relate bulb of the envelope and the whole baked at a to novel means for supporting the heating means temperature of about 400 C. while a current is with reference to the selective radiator, and to passed through the filament heating the same to other features of the invention which will become about 600 C. and evacuated to a pressure of 20 apparent on consideration of the following de about /2 micron in order to remove water vapor scription and of the accompanying drawings, in and other gases which may be occluded in the which: I envelope. The potential is then slowly elevated Fig. l is a view in elevation of one form of the to about 800 0., thus gradually heating the coatradiator, which may be preferred; ing on the filament until the temperature arrives 25 Fig. 2 is a detail partly in section of the radiaat a red heat. Gases emitted from the coating tor unit; and interior of the bulb are in the meantime be- Fig. 3 is a modification oi the radiator of Fig. 1, i s r v d y th va uum p mp and t pumpshowing a different mode of support for the mg is continued until the pressure is approxit mately .5 micron. The oven is then removed 30 Fig. 3a is a view in elevation of another emand the current raised to heat the filament to bodiment of the radiator; about 1200 C. The pump is then shut oh and Fig. i is a view of another modification of the neon gas is again admitted to about /2 mm. of invention; and mercury, and a potential applied and raised until Fig. 5 illustrates a modified type of selective a reddish discharge completely fills the bulb, this so radiator adapted for use in the apparatus of discharge being concentrated intermediate adja- Fig. 4. cent parts of the radiator. The filament temper- In my related application, Serial No. 459,048, ature is then raised to about 1400" C. The bulb filed June 3, 1930 I have described a type of is then exhausted to about .5 micron, thus comenergy radiating device in which energy is rapleting the activating process for the coating. 40 diated by an activated layer of ionized inert To complete the radiator neon gas is admitted gases in juxtaposition to a conductor coated with to a pressure of 50 mm. of mercury, and then ara rich ionizing material. With an appropriate gon gas is also added until the pressure is appressure of gas and proper voltages, it has been proximately 200 mm. of mercury. Of course, the

found that a halo forms about the conductor values of voltages, resistance and gas pressure 45 which serves as an auxiliary conducting path for mentioned may be varied within limits in accordan electric current, and also as an important once with requirements. source of radiation, usable either for lighting Referring now to the drawings, Fig. 1 illuspurposes or for any other purpose which requires trates a radiator of the general type hereinabove the application of radiated energy of definite described, and having improved modifications, 50 wave frequencies, as will now be set forth. In the envelope I0 is Inaccordance with said application, afilament sealed a stem I I, on which is mounted three of appropriate resistance, such, for example, as standards l2, l3, and M. Adjacent the terminals 150 ohms, is coated with various alkaline earth of standards l2 and I 4 is secured a coil 9 of metal oxides such as the oxides of barium, caltungsten wire 15 having a coating of electron 55 emitting material l6 approximately throughout its coiled length. i

The wire of the coil 9 may be either straight or closely coiled so as to increase the effective resistance per unit length. The coating It may be of various alkaline oxides, but a mixture of oxides of barium and calcium may be specified as usable in this particular type of radiator. Within the coil 9 of this coated tungsten conductor is positioned a rod or pencil H which, when heated, selectively radiates in certain well defined frequency ranges, such as that of' the luminous range. Such materials for illuminating purposes are various oxides of rare earth metals such as cerium, yttrium or oxides of thorium, magnesium and calcium.

The pencil I1 is supported along the axis of the coil 9 by means of the inturned ends of the standards l2 and H which penetrate into axial recesses l8 and IQ of the pencil IT, as illustrated in Fig. 2 of the drawings.

The standard I3 is spotwelded or otherwise attached to the approximate mid-point of the coil l5 to serve as an auxiliary support therefor, and prevent sagging with consequent contact of the pencil I1 and the coil l5.

In operation, when the electric potential is applied to the connecting circuits 20 and 2|, which in turn are attached respectively to the conducting standards 12 and I4, the filament IS, with its attached coating I6, is heated until electrons are heavily emitted from the coating and an energized atmosphere of ionized gas forms as a halo about the conductor, the diameter of which depends upon the pressure of the inert gases, such as argon and neon, within the bulb. The heat energy derived from the ionized gas by bombardment, as well as by radiation and convection of gases from the filament l5, heats up the pencil I! to a point where it begins to selectively radiate energy. Where a lamp for illuminating purposes is contemplated, the gases are so chosen and the pencil and heater material is so selected that in the operating temperatures a high density of luminous radiation is provided.

The exact type of radiation may be varied over wide ranges, not only within the luminous range, but above or below said range. For instance, a radiator of ultra-violet energy may be designed as well as a radiator of wave length of lower frequency than that of red light. The total energy eifect is the sum of that derived from'the heating conductor, the ionized gases surrounding the conductor and the emitting solid body, so that a radiator of maximum efliciency is available.

In Fig. 3 a means of supporting the heating conductor I5 is shown, which varies from that of Fig. l in that the approximate midpoint of the conductor is connected by a conductor 30 to a pencil ll, thus forming a ground or shunt connection. The utility of this modification lies chiefly in radiators of the type which employ a high voltage and in which it is desirable to break the potential drop into a series of segments, according to the principles described in my copending application Serial No. 476,960.

In Fig. 4 of the drawings a modified form of radiator is illustrated in which the solid emitter is not a part of the electrical circuit, but consists of an insulated solid cylindrical unit 40, adapted to be positioned within the coated heater coil 4|. This emitter is mounted on the standard 42 in the stem 43 of the bulb 44, and carries at its upper end a fiat enlargement forming the head 45 which serves as the main energy emitter of the device. f

In the case of the prior modification the electrical conductivity of the emitter affects the operation of the device and ordinarily the resistance should be high. In the modification of Fig. 4, however, the electrical characteristics are of minor importance.

In operation, heat as derived from electronic and ionic bombardment, from radiation, and gas convection, is received by the cylindrical member 40 and conducted to the radiating head 45. In addition to the connecting standards 46 and 41 by which the coil 4| is supported, and through which electrical conductance is made to the exterior of the bulb, there is provided an additional supporting standard 40. Other supporting means may also be utilized to the amount necessary to prevent the coil and the heater from sagging and contacting with each other.

In Fig. 5 I have illustrated a modification of the solid emitter of Fig. 4, in that the cylindrical body 40 of selective emitting material, such as calcium oxide, is replaced by a refractory metal conductor 50, such as tungsten, this body terminating in a disc-like head 5|, which in turn fits into a recess 52 formedin the base of a head 53 of selective emitting material of the type utilized in the solid emitter of Fig. 4; that is, calcium oxide. This construction is advantageous, as the greater rapidity of the heat conduction of tungsten or other refractory metal reduces the time limit in which the radiator becomes effective after the electrical circuit is closed. Instead of placing the coating material externally of the coil, the same may be applied within the coil in the shape of 9, rod or pencil or as a plastic core material which is subsequently hardened by baking. Accordingly, in the claims hereto appended, the term coating is intended to cover both inner and outer applications of the coating material.

The gases employed have been referred to as monatomic and as readily ionizable, or as vapors of metals. Other gases than those mentioned, such as nitrogen, may be employed, providing appropriate controlling factors are introduced. A fundamental requirement appears to be in conneetion with these gases that the breakdown potential of the same along the axis of the conductor be less than the potential necessary to raise the temperature of the electron emitting material or coating to its operative temperature of electron emission.

The various turns of the coil 9 are illustrated as separated relatively widely, but in practical operation these coils may be more closely spaced together, and this will be the case whether or not the wire of the coils is straight or itself coiled, as shown in Fig. 1. Moreover, it is not necessary that the coating, if applied externally, be about the whole outer surface of the coils, but may lie only on the inner surface of the coil.

Various other modifications of the invention may be described, all of which utilize the general idea of associating with the combined metal and gas conductor unit a solid emitting unit which is adapted to receive energy from the primary conducting unit, and these modifications are intended base, a rod secured to one or more of said standards, said rod adapted when heated to selectively radiate energy, a heating conductor positioned adjacent said rod and secured to two or more of said standards through which electrical energy is adapted to be received, a coating of electron emitting material containingalkaline earth metal oxides fixed to said conductor, and an inert gas within said envelope, the pressure of said gas being such as to permit the formation of a layer of ionized gases adjacent said conductor, and said rod and conductor constituting the sole sources of the discharge.

2. An energy radiating device comprising the.

' 3. An energy radiating device comprising an envelope, 9. support within the envelope, a rod mounted on said support adapted when heated to emit luminous energy selectively, an electrical conductor adjacent said rod, a coating of electron emitting material containing alkaline earth metal oxides on said conductor, and an atmosphere of ionizable gas within the-envelope at a pressure of about 200 mm. of mercury, said rod and conductor constituting the sole sources of the discharge.

4. An energy radiating device comprising the combination of an envelope, a. support mounted I 1 in said envelope, a'plurality .01 standards mounted on said support, and a rod connected to one of said standards, an electric conductor coiled around said rod, said conductor being supported by other of said standards, an atmosphere of inert gas within said envelope, and means including a coating containing an oxide of the alkaline earth metal group on said conductor to ionize the gas in a region confined to the vicinity of said conductor, said rod and conductor constituting the sole sources of the discharge.

5. An energy radiating device comprising the combination of an envelope, a support mounted in said envelope, a plurality of standards mounted on said support, and a rod connected to one of said standards, a coil of conducting material wound around said rod, said conducting material being supported by other of said standards, an atmosphere of inert gas within said envelope including at least ten percent of neon gas, and means to ionize the gas in a region confined to the vicinity of said coil, said means including an .electron emitting substance having. an electron flow approximately equivalent to barium oxide, said rod and coil constituting the sole sources of the discharge.

6. An energy radiating device comprising the combination of an envelope, a-support mounted in said envelope, a plurality of standards mounted on'said support, and a rod connected to one of said standards, a coil of conducting material wound around said rod, said conductor being supported by other of said standards, an atmosphere including argon and neon gas within said envelope, and means to ionize the gas in a region confined to the vicinity of said coil, said means including an electron emitting substance containing an oxide of the alkaline earth metal group, said rod and coil constituting the sole sources of the discharge.

' CHESTER H. BRASELTON.

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