US1640829A - Incandescent electric lamp - Google Patents

Description

. 1,640,829 Aug. 30,1927. 1A. HEANY I INCANDESCENT ELECTRIC LAMP kFiled. May l5, 1918 :5 sheets-sneu 1 IN V EN TOR.

ATTORNEY Aug. 30, 1927.

J. A. HEANY INGANDESCENT ELECTRIC LAMP Filed May l5, 1918 3 Sheets-Sheet 2 Patented Aug. 30, 1927.

UNITED STATES PATENT OFFICE.

INCANDESCENT ELECTRIC LAMP.

Application led May 15, 1918. Seria1`No. 234,756. l

This invention relates to incandescent electric lamps and has for its objecty the provi-- sion of an improved lamp, which is highly efficient and has an unusually long life. This is accomplished by constructing the glower in the novel manner hereinafter described.

The invention is a modication'of the invention described in my application entitled Incandescent electric lamps, filed July 3, 1916, Serial No. 107,367 and in which the right to claim the invention broadly is reserved.

According to the present invention,`the glower is made of such sizes and in such shapes as to `materially reduce the convection losses. This is accomplished Without sacrificing any strength of the necessary resistivity to produce the proper degree of incandescence, due to the fact that the glower is constructed of materials which possess great strength at the operating temperature, and are capable of 'reaching a high degree of incandescence, even in the small candle power lamps and on relatively low voltages The glower may be cylindrical, tubular, plate-like, hemispherical, nearly spherical in form or any other suitable form'.

In general the glower comprises a resistor preferably of tungsten or tungsten alloy and a support preferably composed of a highly refractory material, such as a rare oxide or a mixture of rare oxides, which possesses marked rigidity at the operating temperature. The resistor is so associated with the support that the former heats the latter to incandescence. The resistor may comprise finely divided refractory metal uniformly distributed throughout the refractory material, may be formed by impregnating refractory metal throughout the refractory material, or may be formed by merely impregnating a thin zone of refractory material with a refractory metal. The resistor may also be composed of refractory metal wire wound in any de- Fired form or may consist of a thread of refractory metal placed in a groove provided in the support. l

The radiating surface of this glower may be of severaldifferent kinds. The resistor may also act as the radiating surface, and may. therefore, be in the nature of a helix or of a portion of a sphere, or be convoluted in any suitable manner and wound upon the support. The resistor may be completely .em-

bedded in the support in which case the Inaterial of the support is the radiating surface, or the radiator may be composed of a thin layer of refractory material different from thaty of the support or of a thin layer of refractory metal. Another form of radiatmg surface is one in which the surface is composed partly of refractory metal and partly of refractory material. When the radiating surface is of this character the metal forming the resistor is partially embedded in the support and the exposed portions thereof are separated by the surface of the support.

Another form of radiating surface of this type is provided when a resistor in which finely divided metal is uniformly distributed throughout the refractory material or refractory metal is impregnated in the refractory material' is used in such a way that the resistor is exposed. In such a case the radiating surface is part refractory metal and part refractory material.

` Thus it is seen that in this glower there may be tive different types of resistors and three different types of radiating surfaces together with several modifications of each type.

The materials used in the construction of this glower must be endowed with certain characteristics. The refractory compound to be used for the support possesses great strength at the operating temperature and is capable of becoming highly incandescent at said operating temperature. Furthermore, the material used in the support is capable of withstanding extremely high heat,

such as that of the oxy-hydrogen flame without being subject to appreciable evaporation or disintegration of any character. Another characteristic of this material is that itl is highly resistive atI the operating temperature so as not to allow current to leak to it from the resistor. Again, it has the property of being a poor conductor of heat as well as of electricity. Another important property possessed by the material of which the support is constructed is that known as Select-ive radiation, or the ability to emit a high percentage of rays in the visible portion of the spectrum at the temperature of operation of the lamp. The materials possessing these qualifications and which are therefore best suited for the purpose areJ the rare earth oxides, such for example as zirminimum. It is 'a well known fact that an increase in theediameter of a filament'or glower reduces the percentage of convection loss. For this reason the cylindrical and tubular forms of lower are so formed that they are relative y large in cioss section as compared with the filament of the ordinary strung type lamp, but are at the same time ver short as compared with said filament an are relatively small as compared with the bulb of the lam As the diameter of the glower is increase its percentage loss approaches, as a limit, that of a plane surface aving the same area. For this reason the lower is also constructed in a flat plate-like orm, so as to approach as nearly as possible a plane surface, thus also reducing the percentage of the convection loss. The hemispherical and nearlly spherical types of glower also serve to re uce the convection losses, due to their peculiar shape and to the fact that they have a relatively large diameter. Furthermore these types retain within their opening the hot gases, thus helping to reduce the convection losses and at t e same time stop evaporation losses, due to the fact that the gas 'within their opening becomes saturated and is then incapable of absorbing any more of the metal.

All these types of glowers may be operate'd either in vacuum or else in an inert gaseous medium, such as nitrogen, argon, helium or the like.

When any of these forms are operated in vacuum they are more elicient than the present vacuum lamp, due to the fact that they suffer but two end losses whereas the present type of lamp suffers two end losses and several supporting losses. Those forms of the glower inl which the refractory metal is exposed may be operated at the same temperatures that the present t pe of vacuum lamp is operated and yet will be more eilicient for the same candle power, because of the reduction of the losses to thc supports.

It is preferable, however, to operate those types of glowers in which the refractory metal is exposed in an inert gaseous medium under a pressure of a little less than one atmosphere. This allows the glower to be operated at a higher temperature, due to the fact that under pressure the volatilizing point is raised appreciably. Those types of glower in which the refractory metal is completely embedded may be operated in vacuum even at a higher temperature than the other in an inert gaseous medium, due to the fact that the refractory material uscd has a much higherl volatilizi'ng point.

The one big advantage of this` glower is vradiating surface is composed of metal.

Figs. 2, 6, 16 and 2() are similar sections in which the radiating surfaces are composed of refractory oxides.

Figs. 7, 8, 21 and 22 are similar sections in which the radiating surface is composed partly of' refractory metal and partly of refractory oxide.

Figs. 9 to 14 and 23 to 28 inclusive are similar sections of further modifications of the tubular type glower.

The glower 34 disclosed in Fig. 1 is composed of a tube 34a of refractory material near the exterior surface of which is embedded a helix 34" of refractory metal wire and on the surface of which is provided a thin sheet 34 of refractory metal. In Fig. 2 the glower 37 is composed of a tube 37 of refractory material on the inner surface of which is placed a helix 37b of refractory metal wire the turns of which are spaced apart merely enough to prevent short circuiting and are let into the tube approximately halt their diameter.

The glower 40 shown in Fig. 3 comprises a tube 40a of refractory material on the inner surface of which is provided a helix 40 of refractory metal Wire, the turns of which are spaced merely enough to prevent short circuiting and embedded enough to prevent displacement. In Fig. 4 the glower 41 comprises a tube of refractory material having embedded therein a helix 41b of refractory metal wire located near the inner surface of the tube. This glower is also provided on its inner surface with a thin sheet 41c of refractory metal. The glower 42 disclosed in Fig. 5 comprises a tubular support 42a of refractory material in which there is embedded a helix 42b of refractory metal wire and on the inner surface of which is located another helix 42c of refractory metal wire. The second helix 42 is in series with-the first helix 42b and is connected thereto at 42e. This helix 42c has its turns spaced apart merely enough toI prevent short circuiting and embedded sufficiently in the refractory material to prevent their displacement.

43 represents the glower as a Whole in Fig. 6 and is composed of a tube 43 of refractory material in which there is embedded close to the. ilmer surface of the tube a helix 43b of refractory metal Wire.

The glower of Fig. 7 is designated as 44 and consists of a tube 44a of refractory material on the inner surface of which is provided a h elix 44h of refractory metal wire, the turns of which are spaced apart their own diameter and embedded approximately half their diameter. In Fi 8 the glower comprises a tube 45a of re ractory material, a helix 45h of refractory metal Wire completely embedded in the said tube and a second helix 45c of refractory metal wire located on the inner surface of the tube and having its turns spaced apart their own diameter and embedded approximately half their diameter. The two helices are connected at 45.

The. glowcr 46 in Fig. 9 consists of a tube 46a of refractory material having a helix 46b of refractory metal Wire on its inner surface and a helix 46c of refractory metal wire on its outer surface. these two helices being connected at 46". The turns of each helix are separated merely enough to prevent contact and are embedded in the support sufficiently to prevent displacement. In Fig. 10 the glower 47 is composed of a tube 47 a of refractory material on the inner surface of Which is provided a helix 47b of refractory metal Wire, the turns of which are slightly embedded in the refractory material to prevent displacement and are spaced merely enough to prevent the adjacent turns contacting with each other. On the outer surface of this glower there is provided a thin sheet 47c of refractory metal.

In Fig. 11 the glower 48 comprises the usual tube 48n of refractory material and is provided with an inner helix 48b and an outer helix 48c of refractory metal wire connected in series at 48". Both of these helices are embedded in the refractory material suflieiently to prevent displacement. The turns of the inner helix are as close as they can be without being in actua-l contact, while the turn-s of the outer helix are spaced apart their own diameter. The glower 49 of Fig. 12 is formed of a tube 49 of refractory material the inner surface of which is provided with a helix 49" and the outer surface with the helix 49c of refractory niet al wire. These two helices are connected with each other at 49. The turns of the outer helix are relatively close to each other but not in contact. while the turns of the inner helix are spaced apart approximately their own diameter. Both helices are slightly embedded in the support to prevent displacement. In Fig. 13 the glower is designated as 5() and comprises a tubular support a of refractory material the inner surface of which is provided with a. helix 50b and the outer surface with a helix 5()C joined to each other at 50e. The turns of each helix are spaced apart their -own diameter and are embedded approximately onehalf their diameter. 'lhe glower 51 of Fig. 14 comprises the tubeI 51 of refractory material on the inner surface of which is provideda helix 51b of refractory metal wire the turns of which are spaced apart their own dia-meter and embedded approximately one-half their diameter. Surrounding the support is a thin sheet. 5lc of refractory metal.

Figs. l5 to 28 inclusive are the same as Figs. 1 to 14 inclusive with the exception of the fact that instead of having helices of iefraetory metal wire the glowers are provided with helical grooves or threads filled with refractory metal. In these figures the reference numerals 53 to 70 inclusive designate the glower as a whole and the reference characters 53a to 7()a inclusive represent the tube'of refractory material which constitutes the support. The reference characters 53b to 70h designate the resisting elements of the repective figures.

In Figs. 15 and 18 the reference characters 53c and 60c respectively designate the thin sheets of refractory metal Which act as the radiating surfaces in these figures. In Figs. 19 and 23 the reference characters 6l and c respectively denote metal filled grooves which act as the radiating surfaces. In Figs. 21 and 22 the reference characters 63 and 64 respectively denote metal filled grooves which together with the refractory material between the turns of the same, form the radiating surface. In Figs. 19, 22. 23. 25. 26 and 24 the reference characters 61". G4". 65". 67e. 68e and 69e denote the connections between the inner and outer helices. In Figs. 23, 24. 25, 26. 27 and 28 there are provided metal helical filled grooves 65". G6". 67". 68", 69b and 70" on the inner surface of the tubes. the surfaces of Which lie flush with the inner surfaces of the tubes. In Figs. 23. 24 and 25 thel turn-s of these grooves are spaced merely enough to prevent short circuitingwhile in Figs. 26, 27 and 28 they are spaced apart their own width. In Figs. 23. 25. 26 and 27 there are provided metal filled helical grooves 65. 67C. 68c and 69c on the exterior of the tubes. the surfaces of which lie flush with the outer surfaces of the tubes. In Figs. 23 and 26 the turns of these grooves are. spaced apart merely enough to prevent contact. while in Figs. 25 and 27 they are apart their own width. In Figs. 24 and 28 the reference characters 66c and 70c denote thin sheets of refractory metal.

In Figs. 1, 3, 4, 5, 9, 10, 15, 17, 18, 19, 23 and 24 the radiating surface is of refractory metal either in the form of a thin sheet of metal or a helix of the metal, the turns of which are spaced close to each other to form almost a continuous surface or a combination of both. In Figs. 1 and 15 this radiating 5 surface. is placed on the exterior of the tube.

In Figs. 3, 4, 5, 17, 18 and 19 the radiating surface is on the interior of the tube while in Figs. 9, 10, 23 and 24 the radiating surface is-both on the exterior and interlor of the tube. In Figs. 3, 4, 5, 17, 18 and 19 the portion'of the support exterior of the helices 1s made thick enough to act as a heat insulator to'force the radiation to come from the interior of the tube.

In Figs. 2, 6, 16 and 20 the radiatin surface is composed of refractory materia In Figs. 2 and 16- the resisting elements are spaced close to the lexterior of the tube and therefore the radiation is from the exterior 2o surface. In Figs. 6 and 20 the resisting elementv is 'placed close tothe interior of the t-ube making the radiation come fromthe internal surface.

In Figs. 7, 8, 11, 12, 13, 14, 21, 22, 25, 26,

25 27 and 28 the radiating surface is composed partly of refractory metal and partly of refractory compound. In Figs. 7, 821 and 22 that portion of the sup ort exterior of the helices is relatively thic and acts as a heat insulator forcing the radiationto come from the interior of the tube. In Figs. 11, 12, 13, 14, 25, 26, 27 and 28 the radiation takes lace both from the interior and exterior of) the tubes.

In several of the glowers, the radiating surface is composed either wholly 'or in art of rare oxides. The oxide used as the ra iating surface may be either the same as that used in the construction of the support or 4o may be a different oxide or combination of oxides from that so made use of.

A simple method of making the glowers above is as follows:

The rare earth oxides such as zirconia, thoria, magnesia or the like in their raw condition, either singly or in combination are thoroughly mixed with a dissipating binder, for example, any hydrocarbon binder. The paste thus formed consisting of the raw oxide or oxides and binder is next molded into strands. The molded strands are then subjected to an extremely high heat, such forexample as that of the oxyhydrogen flame. By the application of this high heat the binder is driven out together with the water of crystallization contained in the oxide or oxides, leaving the oxide in a dehydrated condition. During the dehydration a perceptible shrinkage takes place in the strand. The oxide will not after its dehydration, again absorb any water nor will it be subject to any further shrinkage. This step is a very important one, because without it the glower formed would not be practical. If a glower were to be constructed out of oxides which had not been dehydrated, it could not stand the temperature at which the lam ope-rates Without being seriously affecte When such a glower is placed in a lamp and duced by means thereof to an extremely fine powder. In its pulverulent condition, the oxide is a ain intlmately mixed with a dissipating inder, and a second paste is formed. While in this plastic condition the material is molded into 'the desired shape that the glower i's to be provided with in its final form. The material is then thoroughly dried, either in an oven or by a water bath. At the samev time provision is made for the introduction of the resisting elements. The material at this stage of the process can be easily worked. Grooves or threads can be cut in which refractory wire or metal is to belater placed or vthe resisting elements can be placed in the support at this time. f

Following this step, the support is again subjected to a high heat'to drive outthe `binder and to sinter the oxide into a hard porcellaneous structure.

I claim as my invention:

1. In an incandescent electric lamp, a glower of the type described, comprising a relatively short diameter tube of refractory material, and a resisting element ofrefractory metal partly embedded in the interior surface of said tube capable of heating the tube to incandescence.

2. In an incandescent electric lamp, a glower of the type described comprising a tube 0f refractor material and a resisting element composedy of a closely wound hellx of refractor metal partly embedded in the interior sur ace of said tube and capable of heating the tube to incandescence.

3. In an incandescent electric lamp, va glower of the type described comprising 'a tube of refractory material, a radiating element of refractory metal and a'resisting element consisting of a helix of refractory metal partially embedded in said tube adjacent the interior thereof and capable of heating the glower to incandescence.

4. In an incandescent electric lamp, a glower of the type described comprising a tube of refractory material, an exposed helix of refractory metal on the exterior of the tube and a second exposed helix of refractory metal on the inner surface of the tube.

5. In an incandescent electric lamp, a glower of the type described comprising a tube of refractory material, a helix of refractory metal on one surface of the tube and a helix of refractory metal on the other surface of the tube capable of heating the same to incandescence.

6. In an incandescent electric lamp, a glower of the type described, comprising a tube of refractory material, an exposed helix of refractory metal on the exterior of the tube and asecond exposed helix on the inner surface of the tube, one of said helices being closely Wound.

7. In an incandescent electric lamp, a glower of the type described, comprising a tube of refractory material, an exposed helix of refractory metal on the exterior of the tube and a second exposed helix on the inner surface of the tube, one of said helices having its adjacent turns spaced apart.

8. In an incandescent electric lamp, a gloWer of the type described, comprising a tube of refractory material, an exposed helix of refractory metal on the exterior of the tube, and a second exposed helix on the inner surface ofthe tube, one of said helices being,r closely wound and the other having its adjacent turns spaced apart.

9. In an incandescent electric lamp, a glower of the type described, comprising,- a tube of refractory material, a resistor einbedded in said tube interior havingbr elements positioned uniformly distant from the axis of said tube, and a radiating surface positioned at another distance from said tube.

JOHN ALLEN HEANY.

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