Oct. 15, 1946. 2,409,361 E. KETTLEWELL SEAL FOR ELECTRIC LAMPS AND: SIMILAR DEVICES Filed March 50, 1944 Fig.1. Inven‘tor: ‘ ' Eric e't't'LeweLL, His A‘k't'orneg. - 2,409,361 Patented Got. 15, 1946 omen T STATES PATENT OFFICE SEAL FOR ELECTRIC LAMPS ‘AND SIIVIILAR DEVICES Eric Kettlewell, Kingsbury, London, England, as— signor to General Electric Company, a corpo ' ration of New York Application March'30, 1944, ‘Serial No. 528,661 ‘In Great Britain April 3, 1942 2 Claims. (of. 49-925) 1 . - This invention relates to devices of a type com prising an envelope of quartz or similar refrac tory or vitreous material with an electrode there in and means of current lead connection to the exterior sealed through a part of ‘the envelope structure. -The invention involves novelty in methods of manufacture, as well as in construc tion. The invention is especially applicable to 2 strips projecting therefrom as tags or “stream ers,” the wrapped portion being welded to the electrode. And with respect to steps (3) and (4), it is desirable, in the case of a relatively massive electrode member, that the quartz core have sub stantially the same external shape of cross-sec tion as the adjacent end portion of the elec trode-for instance, if the electrode is a cylin high pressure metal vapor discharge devices, in- » drical rod, the core may be a rod or tube of about eluding mercury vapor lamps which in operation 10 the same external diameter-and-that the quartz sleeve should be collapsed upon most or all the dissipate power considerably exceeding 1 kw. The current connections of such discharge de vices are usually carried through the quartz or wrapped part of the electrode. It is generally undesirable to collapse quartz upon the un wrapped part of the electrode. other vitreous envelopes by means of strip-form lead seals, comprising strips of sheet metal (often 15 By way of example, one embodiment of the so thin as to be quite properly termed foil) em bedded in the vitreous material while it is sof tened or fused by heat. Besides the delicacy or invention will now be described with reference to di?lculty of making such joints, there is the prob electrode assembly constructed as above indi the accompanying drawing, in which: ,Fig. 1 is a perspective or tilted side view of an lem of making satisfactory electrical and me 20 cated; Fig. 2 is a side view of a complete dis charge device embodying this electrode; Fig. 3 chanical connection between the thin strips and is a fragmentary, sectioned elevation of the elec the electrode member to which they lead, par trode assembly; and Fig. 4 is a perspective view of ticularly when this member is relatively massive, a modi?cation of the foil lead-in conductor. as well as of ?rmly supporting the member. In Fig. l, a relatively massive refractory metal It is an aim of this invention to overcome such 25 electrode of a high pressure metal vapor electric di?lculties by improved constructions and lamp is shown as a tungsten rod or cylinder I, methods. Various other features and advantages which may be 30 mm. long and 71/2 mm. in diam of the invention will appear from the following description of a species or form of embodiment eter, for example. Refractory sheet metal or foil and. a mode of fabrication, and from the draw 30 for the electrode wrapping and the seal strips may ing. , consist of molybdenum sheet 0.015 mm. thick. A In manufacturing a quartz envelope device in band 2 of this foi1 (15 mm. wide, for example) is wrapped around one end of the electrode mem accordance with the invention, in the form here inafter described, (1) a part of a refractory metal ber I and welded to it. Two strips 3, 3 of the sheet molybdenum (each 10 mm. wide and 40 electrode member (preferably cylindrical) is mm. long, for example) are each weldedv at one wrapped with thin refractory sheet metal or foil, end to the wrapping 2, while at the other end which is ‘welded to the electrode at a plurality of each strip is welded to a stout external wire lead places, (2) thin strips of refractory sheet metal 4, which may be multistranded as shown. Using or foil adapted for a strip seal are attached and electrically connected to the wrapping, and thus 40 a cylindrical quartz rod (also 71/2 mm. in diam eter) as the core 5 in alignment with the elec to the electrode, (3) the electrode and a quartz trode rod l-——and as shown forming as it were a core in line with it are placed within a quartz prolongation of the electrode-the lead strips 3, 3 tube or sleeve with the metal strips extending and the core 5 are both inserted or ?tted into outward along the core, between the same and said tube, and (4) the said tube (or part of it) 45 a quartz tube or sleeve 6 (of suitable internal bore), so that the strips lie between the core and is collapsed upon the enclosed core and strips, the tube, the wrapped end of the electrode I being and even on the foil-enveloped portion of the elec also inserted or ?tted into the end of the tube. trode. In this procedure, the order or distinction The tube or sleeve 6 is collapsed, by heating and . of steps (1) and (2) is immaterial, and “uniting” the strips and the electrode wrapping may be un 50 softening it, over the whole distance from the boundary between the wrapped and unwrapped derstood to include an original integral union left unsevered: for example, the foil wrapping and the strips may be cut out of the same sheet of metal in one piece and part of this piece wrapped around the electrode end, leaving the 55 portions of the electrode l to slightly beyond the junction of strips 3, 3 and leads 4, 4, and is inter fused and sealed with the core 5 within it. Assuming the tube or sleeve 6 to be itself the 3 2,409,361 . 4 integral sleeve or neck of a quartz lamp envelope What I claim as new and desire to secure by or bulb, the collapsing of this sleeve on the core Letters Patent of the United States is: 5, etc., as just described would complete the in~ 1. In a. seal of the class described, the combina stallation of the electrode I in the envelope. It tion of a metallic rod-like electrode and a core is preferred, however, that the sleeve 6 be a sep 6 member of vitreous material of substantially the arate tube, so that its collapse, etc., as described same diameter aligned in abutting end-to-end merelycompletes a vitreous refractory plug of an relation,,a metallic, foil conductor including a electrode assembly including the electrode I, with portion wrapped around ‘the end of said electrode the lead strips 3, 3 extending outward through adjacent said core member and another portion the seal between the plug sleeve 5 and its core' 5.“ extending therefrom longitudinally of said core Thereafter the plug with the electrode’! carried .1 member," and a‘sleeve of ‘vitreous material fused thereby is inserted into a neck or sleeve portion around said core member and the portion of said In of a vitreous refractory lampenvelope ll,,so v.electrodewhich iswrapped with foil, said foil that the electrode I is exposed‘ in 'the'envelope, and the envelope neck l0 is'softened and col-f 15 .;conductor.,being. embedded in the fused seal. .;2.~In;~a¢seal of, the class described, the combi lapsed on the plug by heat and interfused with it, thus sealing the plug into,_the;.ne'ck,.allaasin nation of a metallic rod~like electrode and a core member-of vitreous material of substantially the dicated in Fig. 2. same ‘diameter aligned in abutting end-to-end Fig. 4 shows a modi?cation of the foil lead-in conductor wherein the wrapped portion 2’ and 20 relation, a metallic foil conductor including a portion wrapped around the end of said electrode the ribbons or “streamers” 3' (corresponding to adjacent said core member and .a‘plurality of the portions 2 and 3 ‘in Fig. 3) are cut out of'the ‘ same sheet of metal in one piece. ribbon portions'extending therefrom longitudi nally of said core member, and a sleeve of vitreous In general, as. a‘ practical ‘matter, :refractory fused around said core member ,and the envelope material. similar to quartz includes any 25 material portion of' said electrode which is wrapped with highly silicious vitreous material which'has a ‘foil, said foil conductor being embedded in the coe?icient ‘of expansion of not more‘ substantially fused seal. than 1L5>< 10‘6‘per degree centigradeas compared "with a correspon‘ding‘coe?icient of expansioniof ‘ 055x104‘ per ' degree’ centigrade for-fused quartz 30 'or quartz glass itself. ERIC KE'I'I‘LEWELL.