. (No Model.)
P. 0. JENKINS.
INGANDESGENT ELECTRIC LAMP. l
y Patented June 28, 1887.
lill/lll lllllllllll/ UNITED STATI-:s
PHILIP OSCAR JENKINS, OP WASHINGTON, DISTRICT on COLUMBIA.
lNCANDESCENT ELECTRIC LAMP.
SPECIFICATION forming part of Letters 4Patent No. 365,384, dated June 28, 1.887.
A Application tiled July 23, 1886. Serial No. 208,833. (No model.)
provements in Incandescent Electric Lamps;
and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in'the art to which it appertains to make and use the. same, reference being had tothe accompanying drawings, and to the letters of reference marked thereon,which form part of this speciiication.
lVIy invention relates to incandescent lamps, and has for its object to furnish a lamp of this class which will give forth a larger volume of light than heretofore, and which will be convenient and practical in use.
It consists incertain details of construction, arrangement, and combinations of parts and application of new materials, which I shall now proceed to fully describe, and the specific points of novelty inwhich willv be particularly designated in the claims.
Referring to the accompanying drawings, Figure 1 is a perspective view of my invention complete. Fig. 2 is an enlarged sectional view of the same with the rubber tubing detached. Fig. 3 is a detail perspective of the inside plate,having the end of the soapstone cylinder inserted therein. Fig. 4 is a detail view of the soapstone cylinder. f Fig. 5 is a detail View of one of the metallic tubes for conducting the gases into the'rubber tubes. Figs. 6
and'7 are detail views of different forms of my` carbon electrodes. Fig. 8 is a view in perspective of the manner of forming my mica casing. Fig. 9'is -an end view of same, showing the projecting or overlapping ends of mica before it is secured down.
Likeletters of reference mark the same parts in all the figures of the drawings.
Referringto the drawings by letter, A is the shell orv casing of mica.
b b are the metallic caps,` the average thickness of which is shown in section in Fig. 2.
' C C are the electrode-wires piercing the ends of cap b b, and d d is the carbon electrode interposed between the wiresC C, protectedby an external insulated graphite shell, and having each end in contact with the wire electrodes, said ends of electrode d each projecting through a central perforation in each of the two disks e', made of insulating substance interposed between the graphite and soapstone casings.
eis the casing, of graphiteor other suitable substance, inclosing the carbon-insulated pencil d.
ff are the soapstone cylinders, having one of theirends respectively piercing the metallic plates g g, which serve t'o keep the plaster or other plastic material from rising up in themica tube, and to press the material iirml y against the inside of the rim and bottom of the metallic caps b b.
h h are the rubber tubes which receive and hold excess of carbon oxide or the gases conducted by the metallic tubes 'i fi from within the mica casing. These tubes M have one end, i', larger than'the other, t, the object of which is to form a support for the ends ofthe rubber tubes. This rubber tube, the ob ]ect of which has been partly explained, is of a Avery elastic nature, being capable of great -distention, and consequently of an Increase of capacity; and it may be attached to the lamp, as shown, or may be secured` only at one end, .having the other free and plugged up to prevent the ingress of air, thereby freeing the lamp from all danger of bursting by the expansion of heat. y
D are modified forms of my carbon pencils, the advantages and uses of which will be hereinafter fully explained.
It is well known to those skilled in the art to which this invention appertains that the required resistance in an electrode for producing intensity of light cannot be obtained eX- ceptin a small electrode or its equivalent in character or capacity, and that the maintenance of thelight cannot be had unless in a vacuum or its equivalent; and, furthermore,
it is known that this equivalent has not hitherto been discovered and utilized; and it will be obvious that a device that will accomplish this result is of great advantage and importance in incandescentlighting, and this is the IOO ing of a cleavable nature, I carefully separate its laminte into very thin pieces, thereby obtaining the required elasticity, which enables me to properly roll it into form without breaking orinjuringit. As shown in Figs. S and 9, it is formed by rolling tightly around a smooth unyielding cylinder of the size required with reference to the intended size of the lamps, then rolling it upon itself several times in a convoluted state. Rubber bands are then applied, or some suitable material is passed around its ends to sustain the eylind rical forms alreadygained. The unyieldingcylinder upon which the mica has been wrapped is then withdrawn, leaving a hollow cylinder of mica of great firmness, one end of which is inserted into a metallic cup filled with some suitable plastic material. The electrode is then introduced and put into electrical contact with this cup by firmly touching its central surface or piercing it, as preferred, and the opposite end thereof is similarly treated.
Having proceeded thus far (premising that I have introduced a small hollow tube in one or both ends, which communicates with the space inside) I fasten a thin rubber tube, first pressing out the air therein and hcrmetically sealing it, its office being semi-vicarious, as hereinafter explained. The free edge of the mica left by wrapping is glued down upon the other layers of same, so that there may be no possible ingress of air.
The increase ofthe volume of light and the maintenance of thesainc for a correspondingly greater length of time is obtained by the einployment of carbon pencils of from one-eighth to one-sixteenth of au inch in diameter, surrounded by a shell of the same or similarsubstance, (graphite beingpreferred, )which isprovided with an aperture of somewhat greater diameter than the electrode inserted therein. Then this shell (when not of the refractory non-eondncting oxides) is insulated both at its ends and upon its inside cylindrical surface. The former is done by intcrposing a solid substance of insulation similarly perforated, so that the small electrode within the shell may pass through it to the wires or poles, and the latter, by coating the small inclosed resisting-conductor with a coating or paste of the oxide ofzirconiuin,aluminum, or any other insulating refractory substance suitable therefor. This arrangement prevents a loss of rcsistance in the inclosed pencil-conductor, al lowing it its full power of conducting the heat generated by the electrical current at once to the shell, which shell becomes incandescent and gives forth from its larger surface a much greater volume of light than can be economically gained by the ordinary methods on a small electrode alone. sVhen it is desired to increase the resistance on an electrode quite large, and at the same time to maintain its size, the diameter is reduced, as will be seen by the accompanying drawings.
The lamps are preferably made three and one-half inches in length, the mica being better adapted for this size than glass, and 1n dition, it may be said that a small lamp 1s more unyielding to pressure than alargerone.
To avoid the combustion of the electrode and the shell, Ido not produce a vacuum by exhausting the air, but obtain an equivalent by reducing or converting the oxygenhwhich supports combustion, into carbonic oxide, 1n which form it is a nonsupporter of combustion, and, together with the nitrogen present, has its only obstacle or disadvantage 1n the expansive property awakened by the heat within. This disadvantage is entirely overcome, as before explained.
To effect the equivalent of a vacuuni 1n a lamp whose small amount of air is inadequate to more than supply a start toward the eombustioncarbons within, it is only necessary to subject my construction of carbon electrode and shell to the action of the electrical cur rent for a few moments, which will produce all combustion that can take place, and there remain only two gases-wiz,carbonic-oxide and nitrogen, neither of which will produce or support combustion. This result 1s comparativel y easy to obtain where the size of the carbons within the lamp is too large for thc quantity of air; and this non-combustiblecondition will remain indefinitely, so long as there can be no ingress of air inthe lamp,whieh contingency is carefully guarded against 1n the construction.
Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-
1. The method, substantially as described, of forming the cylindrical external mica casing, which consists in first separating the lam1- me of the mica into thin elastic sheets or layers, which are then rolled or folded around an unyielding eyli nder of suitable size and shape, then securing the said folds or layers together by gluing or otherwise, whereby 'a hollow transparent elastic mica cylinder or casing ot suitable diameter and shape is formed for incandescent electric lamps, as set forth.
2. The combi nation, with suitable electrodes, of a carbon body projecting at each end through a central perforation in a disk, as shown, surrounding the easing of said electrodes, as set forth.
3. The combination, with suitable electrodes and an insulated body of carbon interposed between said electrodes, of an insulated. graphite casing surrounding the said insulated carbon body, as set forth.
4. The combination,with suitable electrodes, of a carbon body projecting at cach end through a central perforation in a disk surrounding the casing of the said electrodes, having its diameter centrally reduccd,with the insulated graphite or other carbon casing, as set forth.
5. The combination of suitable electrodes, an insulated body of carbon interposed between said electrodes, having its diameter reduced between its extremities and insulated casing surrounding said body, and'suitable soapstone or other cylinders surrounding the electrodes and supported at one end in the- 'between said electrodes, a casing for said bodyinsulating material at each end of the carbon body, and a suitable cylinder for incasing the electrodes, as described.
8. The combination of an incandescent lamp having transparent mica inclosing shell, suitable electrodes, an interposed carbon body between said'electrodes enveloped with a graphite casing, andenveloping cylinders for said electrodes, with a glass reservoir consisting of rubber tubing impervious to air and communicating with the chamber of said lamp, as set forth.
`9. The combination ofthe gas-reservoir consisting of rubber or other tubing impervious to air and communicating with the chamber of the lamps, with an incandescent lamp, as described.
In testimony that I claim the foregoing as my oWn I affix my signature in presence of two witnesses.
PHILIP OSCAR JENKINS.
0. E. DUFFY, MJ.` CALLAN.