US2935825A - Manufacture of electric incandescent lamps and similar devices - Google Patents

Manufacture of electric incandescent lamps and similar devices Download PDF

Info

Publication number
US2935825A
US2935825A US642741A US64274157A US2935825A US 2935825 A US2935825 A US 2935825A US 642741 A US642741 A US 642741A US 64274157 A US64274157 A US 64274157A US 2935825 A US2935825 A US 2935825A
Authority
US
United States
Prior art keywords
flushing
envelope
gas
tube
stem
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US642741A
Other languages
English (en)
Inventor
Bowtell James Norman
Moore John Alfred
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co PLC
Original Assignee
General Electric Co PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by General Electric Co PLC filed Critical General Electric Co PLC
Application granted granted Critical
Publication of US2935825A publication Critical patent/US2935825A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/38—Exhausting, degassing, filling, or cleaning vessels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K3/00—Apparatus or processes adapted to the manufacture, installing, removal, or maintenance of incandescent lamps or parts thereof
    • H01K3/22—Exhausting, degassing, filling, or cleaning vessels
    • H01K3/24—Machines therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S53/00—Package making
    • Y10S53/03—Sealing electron tubes

Definitions

  • INVEN TORS ⁇ lwwes Amv v BOWTE'LL ⁇ Auv l -mezb 4/0026 James Norman Bowtell, Wembley, and John Alfred Moore, Neasden, London, England, assignors to The General Electric Company Limited, London, England Application February 27, 1957, Serial No. 642,741
  • This invention relates to the manufacture of electric incandescent lamps and other devices which are like such lamps in that they have a sealed evaucated or gas-filled envelope, the interior ofwhich is required to be substantially free from impurities.
  • the interior of the envelopes are flushed out several times with a suitable gas, for example clean nitrogen, to remove impurities, before introducing the final gas filling and sealing off, this flushing being effected by repeatedly filling the heated envelope with the gas and then evacuating it, so as progressively to dilute the impurities released by the heating of the envelope from surfaces within the envelope, and especially from the internal surface of the envelope itself.
  • a suitable gas for example clean nitrogen
  • the purity of the final gas filling depends, amongst other things, upon the cleanliness of the flushing gas and on the number of flushings carried out, and in some cases the envelopes require to be flushed as many as ten or more times before the introduction of the final gas filling.
  • one disadvantage which is present with the above method of flushing is that since theingoing and outgoing gases use a common path during their introduction into and withdrawal from the envelope respectively, there is a possibility of impurities which are withdrawn from the envelope being reintroduced therein as each new charge of flushing gas is led into the envelope.
  • a complex valve system is required for controlling the evacuation and flushing processes, and this often forms a trap for some of the impurities withdrawn from the envelope during its evacuation, the impurities trapped thereby tending to be carried into the envelope with a subsequent introduction of the flushing gas.
  • other impurities may be present within the mounting which carries the envelopes during the flushing process and these may be introduced into the envelopes in some cases.
  • the main object of the present invention is to provide A a similar kind, required to be relatively free from irnw purities, and in which it is desired to flush out the en-, velope before sealing off.
  • the flushing gas in introdepend on the dimensions of the device being flushed, in particular on the bore of the pumping stem, and also on the pressures used in carrying out the flushing process.
  • the flushing process should, of course, be carried out just before the introduction of the gas filling, although in some cases, for example where the filling gas is not the same as that used for flushing, the envelope may require to be evacuated between the flushing and filling stages.
  • the invention can be employed in arrangements in which the envelope is repeatedly filled with flushing gas and exhausted, and has the advantage that the vacuum pump may be connected to the pumping stem COIIlIIIlU', ously, so as to have a continuous envelope-exhausting action throughout the flushing process, the flushing gas being introduced into the envelope in a succession of pulses.
  • a continuous pressure difference during the whole of the flushing process such that a continuous unidirectional flow of the finishing gas is obtained.
  • a vacuum pump is then used for reducing the pressure at the point of exit of the flushing gas from the pumping stem to a value considerably less than. atmospheric pressure for enabling a rapid flow of the flushing gas to be obtained whilst enabling the pressure within the envelope't'o be maintained at less than atmospheric pressure, thereby facilitating the release of impurities from the internal surfaces of the envelope.
  • a single flushing of the envelope of an electric incandescent lamp employing-thelatter method takes, on an average, about three to five seconds to effect with' present day'lamp-making machinery, depending on the volume of the envelope, the dimensions of the pumping stems and the efficiency of the vacuum pump, the complete flushing taking several times longer, depending on the number of individual flushings required.
  • the pressureat the point of exit of the flushing gas from the pumping stem is of the order of 0.5- millimetre mercury, and the pressure at the point of: entry into the envelope such that a pressure of about 20 millimetres of mercury is maintained within the envelope
  • the final gas filling is preferably also introduced into .the envelope through the Hushing tube before the withdrawal of the tube from the pumping stem.
  • the flushing gas is preferably nitrogen, or a mixture of nitrogen and argon as used for thefinal gas filling.
  • the flushing gas may be released to the atmosvV shape, the aperture of the stem within the envelope lying'between-the'two arms of theV. If the invention is to be applied with devices in which the aperture of the pumping stem within the envelope lies 7 to the side of the axis .of the main part of the stem, the
  • Apparatus for carrying out the flushing of envelopes of incandescent lamps or like devices having a single pumping stem may comprise an exhaust chamber connected or arranged to be connected to a vacuum pump, means for connecting the exhaust chamber to'the pumping stem of a lamp for exhausting the lamp envelope in use of the apparatus, and a tube extending hermetically but slidably through an aperture in part of the .wall of said chamber with its axis aligned with the axis of the pump ing stern of a said lamp when mounted in the apparatus, said tube being arranged to be connected outside the exhaust chamber to a source.
  • the devices with which the method and apparatus of the invention are used are preferably constructed so that the aperture of the pumping stem within the envelope lies --substantially on the axis of the main flushing tube should be sutiiciently resilient to ensure that on the introduction of thetube into the stem the free end of the tube tfollows th e curvature of the stem until it emerges from the aperture 'at the end of the stern within the envelope.
  • Figure '1 shows a sectional view of part of the apparatus employed in carrying out said method, before the introduction of the flushing gas
  • Figure 2 shows a sectional view of part of the apparatus, at right angles to that shown in Figure ,l, as the flushing process is being carried out
  • Figure '3 shows a plan section of a lamp during the flushing process across the line XX in Figure 2
  • Figure 4 shows the apparatus employed in flushing a different form of lamp from that illustrated in Figures 1 to 3.
  • the apparatus comprises a flushing head 1 in which a lamp bulb '2, having the pinched foot-tube 3 sealed thereto but with the pumping stem 4 not yet sealed off, is arranged to be mounted for carrying out thefiushing process, the bulb 2 being supported in the manner shown with the stem 4 extending'downwa'rds through an apertured rubber gland 5 arranged to grip the stem as in known flushing and sealing apparatus.
  • the flushing head 1 comprises a tubular exhaust chamber 6 arranged with its axis vertical and provided near the top with an inwardly directed annular flange 7, on which the gland 5, in the form of a cylinder having ,a circular hole extending coaxially through it, rests with said hole in alignment with the hole 9 at the centre of the flange 7.
  • the diameter and axial length of the gland 5 are such that it just fits within the member 6 and, whenresting on the flange 7, extends almost to the top of the member as shown.
  • the outer surface of the exhaust chamber 6 is threaded for a short distance from the upper end, and on to this threaded part is screwed an internally threaded cylindrical cap 10, closed at the top apart from a central hole 11 through which the stem 4 of the lamp bulb 2 projects.
  • a thrust bearing 12 sandwiched between two annular metal washers 13 and 14 is interposed between the top of the gland 5 and the closed endof the cap 10, and as the cap is screwed further'on to the top of exhaust chamber 6 the gland is compressed between the lower washer ,14 and the flange 7, which causes it to grip tightly the stem 4 of the lamp and form a hermetic seal between the stem and the gland, the unscrewing of the cap allowing the gland 'to release the stem.
  • a lever 15 is attached-to the cap 10 for facilitating the gripping and release of lamps carried by the-flushing head, and the screw threads are so assesses s arranged that the'stems of the lamps can be gripped and released with'only a partial turn of the cap 10.
  • a metal side tube 8 communicating with the interior of the chamber through an aperture in the wall, and connecting it to a vacuum pump 40 (see Figure 4) through a suitable control valve 41.
  • the exhaust chamber 6 carries an outwardly extending flange 16 and to this is screwed a similar flange 17 projecting outwardly from a hollow cylindrical stub 18 of the same diameter as the chamber 6 and arranged coaxially with respect to it.
  • a rubber gasket 19 between the stub and the bottom end of the chamber provides a hermetic seal between the two parts of the apparatus.
  • the outer surface of the stub .18 is threaded in a similar manner to the top of the chamber 6 and similarly carries an internally threaded cylindrical cap 20, this cap being closed at its lower end.
  • the stub is provided at the top with an inwardly directed annular flange 21 between which flange and the closed end of the cap 20 is arranged a cylindrical apertured rubber gland 22, similar to the gland 5, a thrust bearing assembly 23 sandwiched between two annular washers 24 and '25 being similarly interposed between the closed end ofthe capi20 and the adjacent end of the gland 22.
  • a hollow tube 26 Through the hole at the centre of the gland 22 and a corresponding hole in the closed end of the cap 20 extends a hollow tube 26, and the cap 24 is adjusted so that the rubber gland 22 is compressed against the sides of the tube 26 by an amount which allows the tube to slide axially within the gland but at the same time forms a hermetic seal between the 0.1 millimetre and an external diameter of 1.2 millimetre,
  • the tube 28 communicating with the interior of the tube 26 through a small hole 29 in the centre of the disc 27.
  • the disc 27 preferably extends into sliding contact with the inner surface of the exhaust chamber 6 for guiding the movement of the tube 26, and is perforated exteriorly of the tube 26 to allow gas to pass through the disc freely along the outer sides of the tubes 26 and 28.
  • the lower end of the tube 26 is closed but the tube is connected through a side tube 30 and a flexible pipe 42 (see Figure 4) to a source 43 of flushing -gas, a further control valve 44 being included between the source, and the tube 26 for controlling the flow of flushing gas to the tube 26 in operation of the apparatus.
  • the valve, 44 may, for example, consist, as shown schematically in Figure 4, of a valve member 46 biased towards a seating 41" by means of a spring 48, and movable away from the seating to open the valveby meanso'f a cam:49 or other suitable means.
  • Other forms of control valve can, however, obviously beused if desired.
  • a furthersource of filling-gas might in some-cases also be connected to the tube 26 through another control'valve (not shown),.as will be further explained later.
  • the tube 26 is arranged to slide axially between'two limiting positions in use of the apparatus and when the tube 26 is at its lowest position the top of the flushing tube 28 is arranged to lie just within the hole'9 at the centre of the annular flange 7 at the top of the exhaust chamher 6, the raising of the tube 26 to its upper limiting position causing the top of the flushing tube 28 to enter in to the stem 4 of a'lamp bulb 2 carried by the flushing head and to project into the interior of the bulb, preferably somewhat further thanthe position shown in Figure 2.
  • the pinch 31 of the foot tube 3 may, as shown more clearly, in Figures 2 and3, be formed with across-sectiomin planes perpendicular to the lamp axis, substantially in the form of the letter V with the glass support stem 32 for the filament supports 33 located at the apexlof the V, and the aperture ofthe umping stem 4 in alignment with the axis of the main part of the pumping stem and lying between the arms of the V.
  • the aperture of the pumping stem within the lamp envelope may, as shown in Figure 4, lie to the side of the axis of the main part of the stem, and for flushing such lamps the flushing tube 28 should be suitably resilient so that it follows the curvature of the stem when inserted therein, as illustrated in the figure.
  • the air in the bulb is partly removed by connecting the exhaust chamber to the vacuum pump 40-whilst the tube 26 is at its lower limit of travel. After a period of about 1 to 2 seconds, the tube 26 is raised so that the top of the flushing tube enters the lamp bulb as described.
  • the flushing gas is allowed to enter the bulb through the flushing tube 28, the gas scouring the inside of the bulb and leaving by the annular gap formed between the flushing tube 28 and the stem 4 of the bulb 2, as indicated by the arrows in Figure 2.
  • the turbulence of the flushing gas ensures good flushing, and sincethere is a continuous flow in one direction there is no danger of impurities, after leaving the bulb, being reintroduced-by the incoming gas.
  • the rate of introduction of the flushing gas' is preferably such that the internal pressure of the bulb is about 20 millimetres mercury and we have found that with this pressure the bulb is flushed, that is to say there is a complete change of gas within the bulb, in about 0.5 second, a continuation of the flushing process for about 15 seconds being found to be sufficient to give a good cleansing of impurities from interior of the bulb.
  • a further advantage of the arrangement in accordance with the invention is that the degree of gas-tightness at the glands 5 and 22 implied by the use of the term hermetic can be less than with comparable known arrangements, since any 'inleaking gas would tend to be drawn away by the vacuum pump rather than pass into the lamp bulb.
  • the flushing gas may, if desired consist of the gas mixture employed as the filling of the bulb after sealing off, for example a mixture of argon and nitrogen.
  • the flushing gas will be released to the atmosphere, although in some cases, especially where a mixture of argon and nitrogen isemployed, it may be desirable for the gas leaving the bulbs during the flushing process to betrapped and used again after purifying.
  • the valve 44 being open continuously throughout the flushing 'process so as-to produce a steady flow of the flushing gas o the bulb .2, thm n gas fi n e be ntrod into ,the bulb through the flushingtube cash r] vis then lowered, and the stem 4 is finally sealed off.
  • flushing gas for example pure nitrogen
  • offiushing gas and filling gas are required .to be .connectable to the tube 26 and the bulb should be evacuated completely between the flushing and filling processes.
  • the gas used for flushing is the same as that of the final filling, such complete evacuation will, .ingeneral, not be necessary.
  • the bulb does not have the same length of time to cool down, and it may therefore be desirable, in order to save further time in the manufacture of the lamp, to seal the bulb whilst its internal pressure is above atmospheric, and allow the pressure to fall to the required final value after cooling, for example to about 700 millimetres mercury. Any suitable known ,methods of sealing envelopes havinginternal pressures in excess of atmospheric can be employed for this purpose. .Sealing a bulb whilst hot has the additional advantage that the reabsorption of impurities by the internal sur- "face of the bulb, which sometimes occurs on cooling, is prevented. I a
  • the machine employed for carrying out the flushing process will carry .a plurality of flushing heads, for example each congstructedas described by -way of example, ,in order to enablerit to be usedfor mass production processes.
  • the machine may conveniently consist of a rotatable table carrying a plurality, say twenty, of flushing vheads arranged on the circumference of av circle centeredonthe axis of rotation, the unflushed lamps being ,each placed on the machine in an empty flushing head as the head reaches a predetermined position on rotation of the table, and the flushed and sealed lamps being removed from the flushing heads when they reach another-position; for example they may be transferred to further apparatus for the attachment of the lamp caps.
  • a machine including a plurality of flushing heads as .aforesaidcarricd by a rotatable table
  • the gripping and-release of the lamp stems by'the flushing heads, the raising and lowering of the tube 26, the introduction of the flushing gas and final gas filling and the operation of the valve in the vacuum yStem may all be arranged .to be effected automatically as the table rotates, for example by means of suitably arranged cams, and if desired automatically operated means may be employed .for transferring the lamps to and from the machine.
  • a method of manufacturing a said electric incandescent lamp or like device having a sealed envelope containing a gas filling wherein the envelope is flushed before sealing by a method according to claim 1 and wherein, after the completion of the flushing process, the final gas filling is introduced into the envelope through the saidtubular member before the tubular member is withdrawn-from the pumping stem.
  • Apparatus for carrying out the flushing of envelopes of incandescent lamps or like devices in which the envelopes are of the kind comprising a glass bulb having a single elongated pumping stem extending from the bulb comprising an exhaust chamber having an opening for receiving the pumping stem of a said envelope and means ,for hermetically closing the gap between the stem and theside of the opening when the stern has been inserted into theopening, means for connecting the exhaust chamher to a vacuum pump for exhausting the envelope in use of the apparatus, and a tube extending hermetically but slidably through an aperture in part of the wall of said chamber with its axis aligned with the axis of the pumping stem of the device when the latter is mounted in the apparatus, said tube being arranged tobe connected out- .side the exhaustcharnber to a source of gas for flushing the interior of the device envelope and being connected within the chamberto a flushing tube which is movable with it relatively to the chamber so that the flushing tube can be inserted into the pumping
  • Apparatus according to claim 7 designed for flushthe interior of theenvelopes of electric incandescent lamps, or like devices of the kind in which the, aperture of the'pumpingste n at the end within the envelope liesto the side of theaxis of the main part of .the stem so that the stem follows a curved path at that end, wherein the flushing tube isof such resilience that on being introducediinto thepumpingstem the free end of the tube can'follow the curvature of the stem until it emerges from said aperture.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Cleaning In General (AREA)
US642741A 1956-02-28 1957-02-27 Manufacture of electric incandescent lamps and similar devices Expired - Lifetime US2935825A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6215/56A GB820446A (en) 1956-02-28 1956-02-28 Improvements in or relating to the manufacture of electric incandescent lamps and similar devices

Publications (1)

Publication Number Publication Date
US2935825A true US2935825A (en) 1960-05-10

Family

ID=9810510

Family Applications (1)

Application Number Title Priority Date Filing Date
US642741A Expired - Lifetime US2935825A (en) 1956-02-28 1957-02-27 Manufacture of electric incandescent lamps and similar devices

Country Status (5)

Country Link
US (1) US2935825A (xx)
DE (1) DE1088611B (xx)
FR (1) FR1167327A (xx)
GB (1) GB820446A (xx)
NL (2) NL214962A (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3028712A (en) * 1959-06-01 1962-04-10 Gen Electric Apparatus for gas filling electric lamps
US3311439A (en) * 1962-03-22 1967-03-28 Lampes Elect Fab Reunies Method of filling electric incandescent lamps, discharge tubes or the like with gas and of sealing the same
US20090290130A1 (en) * 2006-10-03 2009-11-26 Yoshifumi Nishimura Light source lamp cooling apparatus and projection display apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL290353A (xx) * 1962-03-22
DE1270174B (de) * 1964-04-29 1968-06-12 Patra Patent Treuhand Verfahren und Vorrichtung zum Entlueften und Gasfuellen des Gefaesses elektrischer Lampen durch Spuelen

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1406380A (en) * 1920-04-12 1922-02-14 Heath Wilfrid Paul Process of and means for putting up powdered milk and other food products in a sterile atmosphere
US1854471A (en) * 1928-05-15 1932-04-19 Owens Illinois Glass Co Apparatus for producing hollow glassware
US2101092A (en) * 1934-12-28 1937-12-07 Gen Electric Liquid contact switch
US2215100A (en) * 1937-05-22 1940-09-17 Westinghouse Electric & Mfg Co Method and machine for sealing vitreous vessels
US2722355A (en) * 1951-07-31 1955-11-01 Gen Electric Method and apparatus for loading flash lamps
US2740570A (en) * 1952-10-01 1956-04-03 Gen Electric Method and apparatus for exhausting and sealing-off lamp envelopes
US2759646A (en) * 1955-03-31 1956-08-21 Westinghouse Electric Corp Method and apparatus for loading flash lamps

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL19038C (xx) * 1926-04-14
BE449302A (xx) * 1942-02-03

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1406380A (en) * 1920-04-12 1922-02-14 Heath Wilfrid Paul Process of and means for putting up powdered milk and other food products in a sterile atmosphere
US1854471A (en) * 1928-05-15 1932-04-19 Owens Illinois Glass Co Apparatus for producing hollow glassware
US2101092A (en) * 1934-12-28 1937-12-07 Gen Electric Liquid contact switch
US2215100A (en) * 1937-05-22 1940-09-17 Westinghouse Electric & Mfg Co Method and machine for sealing vitreous vessels
US2722355A (en) * 1951-07-31 1955-11-01 Gen Electric Method and apparatus for loading flash lamps
US2740570A (en) * 1952-10-01 1956-04-03 Gen Electric Method and apparatus for exhausting and sealing-off lamp envelopes
US2759646A (en) * 1955-03-31 1956-08-21 Westinghouse Electric Corp Method and apparatus for loading flash lamps

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3028712A (en) * 1959-06-01 1962-04-10 Gen Electric Apparatus for gas filling electric lamps
US3311439A (en) * 1962-03-22 1967-03-28 Lampes Elect Fab Reunies Method of filling electric incandescent lamps, discharge tubes or the like with gas and of sealing the same
US20090290130A1 (en) * 2006-10-03 2009-11-26 Yoshifumi Nishimura Light source lamp cooling apparatus and projection display apparatus
US8403499B2 (en) * 2006-10-03 2013-03-26 Nec Display Solutions, Ltd. Light source lamp cooling apparatus and projection display apparatus including detecting gas pressure to control light source

Also Published As

Publication number Publication date
DE1088611B (de) 1960-09-08
NL105254C (xx)
NL214962A (xx)
FR1167327A (fr) 1958-11-24
GB820446A (en) 1959-09-23

Similar Documents

Publication Publication Date Title
US2254905A (en) Exhaust machine and method of protecting exhaust systems
US2023628A (en) Method of and apparatus for manufacturing electric lamps
US2935825A (en) Manufacture of electric incandescent lamps and similar devices
US2914371A (en) Method of making miniature lamps
US1461155A (en) Method of and apparatus for manufacturing incandescent lamps
US5037342A (en) Method of making an electric lamp, and more particularly a lamp vessel in which electrodes are retained in the lamp by a pinch or press seal
US2259165A (en) Incandescent lamp and the like and method of making same
US2403073A (en) Method and apparatus for gas filling and tipping-off envelopes
US2006568A (en) Method of sealing metal wires to glass
US2401638A (en) Method of vacuum sealing
US2678761A (en) Exhaust head assembly
US2494915A (en) Method of gas-filling and sealing vessels
US3377496A (en) Gas filled envelope for a spark gap or the like
US2561838A (en) Tipping-off method
US3404933A (en) Method and apparatus utilized in repairing electron tubes
US1945769A (en) Method of sealing off
US2201694A (en) Method and apparatus for manufacturing electric lamps and similar articles
US2794699A (en) Manufacture of small lamps
US2788028A (en) Tubulation and glass ejection system
US2235510A (en) Valve apparatus
US2277691A (en) Apparatus for lamp manufacture
ES342745A1 (es) Un dispositivo de lampara incandescente.
US3901573A (en) Method of processing tungsten halogen light bulbs
GB242303A (en) Process and machine for the manufacture of incandescent lamps, thermionic valves and like apparatus
US3294468A (en) Method and apparatus for manufacturing fluorescent lamps