US2215100A - Method and machine for sealing vitreous vessels - Google Patents

Description

' pL17.1940. D.s.GUsT1N 2,215,100

METHOD AND HACHINE FOR SEALING VITREOUSYESSELS Filed May '22, 1957 2 Sheets-Sheet. 1

F v7 I ATTORNEY p 7, 1940. D. s. GUSTIN 2,215,100

IETHQD AND HACHINE FOP. SEALING VITREOUS VESSELS v Filed lay 22. 1937 2 sh eets-sh eet z \Ri INVENTOR' r Q l B Mm ATTORNEY Patented Sept. 17, 1940.

' UNITED STATES METHOD AND MACHINE FOR SEALING YITREOUS VESSELS Daniel S. Gustin, Bloomfield, N. J., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa, a corporation of Pennsylvania Application May 22, 1937, Serial Nb. 144,143

13 Claims. This invention relates to the sealing of vitreous vessels, and more particularly to tipping of! exhaust tubes of incandescent electric lamps containing gas at a pressure higher than atmos- 5 pheric..

The principal object of my invention, generally considered, is the tipping ofl! of the exhaust tubes of incandescent electric lamps which have been filled with gas at a pressure higher than atmospheric.

Another object of my invention is the provision of a method and machine for tipping of! exhaust tubes'while enclosed in a space containing gas at a pressure higher than atmospheric.

A further object of my invention is the tippingoff of exhaust tubes of vitreous vessels, such as incandescent electric lamps, by a sharp oxyhydrogen flame.

Other objects and advantages of the invention relating to the particular arrangement and construction of the various parts will become apparent as the description proceeds.

Referring to the drawings, Figure 1 is a view, partly in side elevation 25 and partly in vertical section, of a fragmentary- Figure-5 is a fragmentary horizontal sectional view, on the line 5-5 of Fig.2, in the direction 40 of the arrows.

Figure 6 is a bottom plan of that portion ofthe apparatus shown in Fig. 5.

Incandescent electri lamps, as commonly manufactured, include aglass bulb having a reduced or neck portion into which a so-called stem is sealed. The stem includes what is termed a flare tube, one end of which is flanged or flared and sealed to the bulb neck and the 50 other'end terminates in a flattened portion or press, through which conductive lead wires are sealed and upon "which a filament is mounted.

Within the flare tube and'extending downwardly from the press are the leadwires, and an ex- 55 haust tube leads from an orifice in the flare tube or press, for the purpose of exhausting the bulb. or filling it with gas at a desired pressure.

When manufacturing vacuum lamps, it has been the practice to insert the exhaust tube into a port leading 'to a vacuum pump and after the 5 air or gas has been exhausted from the bulb, the tube is heated until the wall thereof collapses, whereupon the lamp becomes sealed and may be removed, in a well-known manner, by a pulling or stretching operation.

when, however, the lamp is filled with an inart gas at a pressure higher than atmospheric, the exhaust tube upon being heated will not collapse, but rather tends to expand or blow out due to the internal pressure. The method which I propose to employ for sealingovercomes this tendency to expand or :blow out, by performing the tipping ofl' operation in an atmosphere highi'er than normal atmospheric pressure, or corresponding with the pressure of the gas in the lamp bulb andexhaust tube therefrom, that is, preferably substantially equal to or higher than said gas pressure.

In the drawings of a preferred or selected embodiment of my invention, an incandescent lamp I0 is shown having an exhaust tube ii inserted in apertured exhaust rubber I! of a head or exhaust port It. The head is carried on a conveyor i4 and connected through a vacuum line lito suitable vacuum pumps not'shown.

,- Inasmuch as apparatus for exhausting and gas filling lamp bulbs is well known in the art, the mechanism therefor is only fragmentarily illustrated in order to show the improvement embodying the present invention. W The conveyor It includes a cap l8 screwthreaded to a fitting l1 and adapted to press a washer l8 through ball bearings I9. The cap maybe rotated at the proper time, by means of its laterally extending arm 20, to either press the rubber l2 about the exhaust tube It or releasethe pressure thereon'to facilitate insertion therein or withdrawal therefrom of an exhaust tube.

Assuming that the exhaust tube I lof the lamp it! has been clamped in the position illustrated and the lamp has been rotated through the stages wherein itwas-exhausted to the proper degree, the desired inert gas is admitted to the lamp I0 through the exhaust tube II from the inert gas line 2|, as will be clear from a consideration of Fig. 1. Before admitting gas, however, the vacuum line II is cut oil from the lamp by pressure applied to the rubber tube connection 22, in a 'well known manner, as by means oflthe member II.

- tube ll passes between and separates thebaflle ries the burner 4|. Said burner 4| is generally plates 24 and 25, as by moving from the left to take the position shown in section in Fig. 3, where it is received in portions of the plates and parts depending therefrom which are notched to provide circular apertures, in which the tube snugly fits when the apparatus is closed;

The bafiie plates 24 and 25 carry mechanism, which will now be described in detail, for performing a tippingoff operation on the exhaust tube ll, while the portion of said tube being tipped off is subjected to a pressure higher than atmospheric. Secured to the lower surfaces of said baffle plates 24-and 25 are burner shield sections 26 and' 21. These sections have their upper edge portions flanged, as indicated at 28 and 29,

and secured to the lower surfaces of the baffle plates 24 and 25, respectively, by anyv desired means as, for-xample, welding or brazing 30 and3l.

The bafiie plates 24 and 25 ,are pivotally mounted on a fulcrum screw 32 and together with their supported shields 26 and 21, are normally held in closed position about the associated exhaust tube II by means of a spring 33 operating on extensions 34 and 35 from said baffle plates 24 and 25, re spectively, so that after the exhaust tube has separated the baflle plates, to the position shown by dotted lines in Fig. 6 while moving in the direction indicated by the arrow, it finally reaches the normal position designated in said figure by the reference character ll, whereupon the baffle plates and associated burner shields close therearound, forming a substantially air-'- tight chamber enclosing the portion of said exhaust tube immediately below the bulb ,of the lamp H). v I V In order to effect a sealing operation in a chamber 59 so formed, the baflie plates 24 and 25 are connected to a gas outlet block designated by the reference character 36. Said block closes the back or right-hand side of the chamber 59 formed by the burner shield portions below the bame plates as viewed in Fig. 2. Connected to the gas outlet block 36 is a pipe 31 which may supply the desired air pressure to the chamber through port 38.

' The front or inner face of theblock 36 has an aperture 39 receiving a screw 40 which car- U-shaped in plan, as shown most clearly in Fig. 5, and provided with ports 42 and 43, for a suitable mixture of hydrogen and oxygen, for example, or a suitable mixture of other combustible gas and oxygen, air, or a mixture thereof. These ports eachtermlnate'in a plurality of burner orifices 44 from the port 42, and 45 from the port 43, which orifices are very so that the oxyhydrogen or 7 other flame produced beyond said openings will not backfire and is very fine and sharp.

In order to provide for feeding the gases mentioned to the ports 42 and 43, a gas inlet block 46' is secured to the upper portion of the outlet block 36. The block 46. has downwardly extending ports 41 and 48 with lower openings registering with the upper ends of ports in the outlet block 36 connecting with the burner ports 42 and 43, respectively, soas to provide for the transmission of the gases' from the manifold nipples 49 and 50 from the gas mixer.

The rear or right-hand portion of the gasinlet block 46, as viewed in Fig, 5, has arms and 52 straddling the pivot head 53 in order to pivotally their uppermost or chamber-closing position by -means of a spoon spring 58, the rear portion of which is secured to the pivot head 53 as by means of a' nut-12 threaded on the fulcrum screw 32.

In order to allow for pivotal motion of the baflles 24 and 25 about their pivot pin or fulcrum screw 32with respect to. the gas outlet block 36 and at the same time allow movement thereof with respect to the connected.- inlet and outlet blocks, and burner 4 I, about their horizontal pivot screws 54 and 55, so that the bailies 24 and 25 and the burner shield sections 26 and 21 may be firmly pressed into tight engagement with the adjacent 'face of the outlet block 36, the front or bafiie and shield engaging surface of the gas outlet block 36 is made spherical about a center cor-' responding with the point of intersection between the vertical axis about which the baflles 24 and 25 pivot, and the horizontal axis about which reference character 63 and the rear upright edges 64 and 65 of the burner shield sections 26 and 21, respectively, are made circular in outline to correspond with the curvature at the places where engagement takes place, as shown inost clearly in Figs. 2 and 4.

The 'rear edges of the lower walls of the burner shield sections 26 and 21 are also formed circular in outline, the narrow outlet-block-engaging faces being correspondingly spherical, as shown most clearly in Fig. 6, and as designated by the reference characters 66 and 61. baiiles 24 and 25 have their corresponding edges formed circular in outline, the narrow faces being correspondingly spherical where they engage the gas outlet block 36, as designated by the reference characters 68 and 69 in Fig. 3.

Likewise, the

25 are free-to open and close between the full line positions and those shown dotted in Fig. 6, while at the same time they are free to pivot about their horizontal axis with respect to the gas inlet and outlet burner blocks, to release the gas pressure if it becomes excessive, said battles and associated parts being normally pressed firmly into engagement with the curved face 63 of the outlet block 36 to form a substantially airtight chamber in which the tipping off operation is performed.

I In order to limit. upward swinging movement of the baflies and associated parts with respect to the inlet, outlet and burner sections 46, 36 and 4|, I provide a set screw 16 passing'thorugh the gas inlet block 46 and with its lower and normally engaging, or adapted to engage, a flange 1| on the pivot head 53 which rests on the baflles 4 24 and 25. Said flange 1| has a stud 13 depending therefrom as a locating pin between the baiiles 24 and 25. The set screw 10 may be locked in adjusted position by means of a nut 14. I

T It will therefore be seen that the bulb of the lamp in may be exhausted, filled with. an" inert gas and finally moved to a position where that portion .of its exhaust tube I immediately be-,

low the neck of the bulb is enclosed in the chamber 59 formed by the baiiie plates 24 and 25 above, the burner shields 26 .and vTI to the sides and front, and the gas outlet block 36 to the rear. While so enclosed an oxyhydrogen flame, or other hot heating means, is positioned to create a heat zone about the tube II, at a point designated by the reference character 60, to rapidly seal and cut oil the tube while air pressure,-supplied from the pipe 31, prevents expansion of the exhaust tube ll, while allowing it to contract naturally, in accordance with the surface tension of the glass, to secure the desired seal. During the sealing or tipping off operation, the lead wires SI and 62 are of course bent to lie. above the baflle plates 24 and 25, protected from damage due to excessive heat.

The bailies are pivotally mounted about a pin so that they may move away from and toward one another to allow for the reception and release of the exhaust tubes of lamps associated therewith, and pivotally mounted about a horizontal axis with respect to the gas outlet block and associated parts while spring-pressed upwardly, thereby maintaining the chamber 5.9

closed to as great an extent as possible and avoiding an unnecessary escape of compressed air, even when the baiiles are open for the reception of an exhaust tube. The bulb of the lamp l0, after being tipped oil, may be removed either by hand or by'the usual automatic means.

4 Although a preferred embodiment of my invention has been disclosed, it will be understood that modifications maybe made within the spirit 2: The method of sealing a vitreous vessel having a tubular extension, after said vessel is filled with a gas above atmospheric pressure, comprising enclosing only a, portion of said extension in a chamber, creating gas pressure above atmospheric in said chamber, and tipping of! the enclosed portion of said extension while sub- Jected to said pressure. I

3. The method of tipping of! an exhaust tube from a vessel containing a 'gas at.a pressure above atmospheric, comprising enclosing only a portion of said exhaust tube in a chamber, creating a gas pressure in said chamber substantially equal to the pressure in said vessel, and

heating said exhaust tube in said chamber until I a seal is eflected ing positioning only a portion of said-tube in an enclosed space, introducing into said space a gas at a predetermined pressure atleast as high as that in said tube, and heating said portion to collapse the wall thereof and close the passage in said tube while in said enclosed space.

6. The method of tipping oil larnps, comprising enclosing only portions of the exhaust tubes thereof in a closed chamber introducing gas at a pressure above atmospheric, and directing oxyhydrogen flames thereon.

'7. A machine for tipping oif exhaust tubes of vessels containing gas at a pressure higher than atmospheric, comprising a chamber enclosing a tipping off burner, and formed of movable walls accommodating the exhaust tube.

8. A machine for tipping off exhaust tubes of vessels containing gas at a pressure higher than atmospheriq'comprisihg a chamber defined by pivoted walls enclosing a tipping oif burner, accommodating only an exhaust tube, and means for introducing compressed air into said chamher.

9. A machine for tipping off the exhaust tubes of incandescent electric lamps, comprising a chamber defined by pivotally mounted walls which are normally pressed together but movable away from one another to admit exhaust tubes, a tipping ofi burner normally enclosed by said walls, and means for introducing gas at higher than atmospheric pressure into the space deflned. by said walls.

10. A machine for tipping off exhaust tubes of incandescent electric lamps, comprising a gas inlet block, a gas outlet blocli depending therefrom, a pair of baiiles pivotally movable about a normally \vertical axis, complementary burner [shield portions carried by said baffies, said baffies and shield portions being pivotally mounted to rotate with respect to said blocks about a normally horizontal axis, said baflies, shields,

.and outlet block normally engaging surfaces of one another to define a chamber, a burner block secured to said outlet block and normally enclosed in said chamber, the surface of said outlet block engaged by said baflles and shields being spherical with itscenter at the point of intersection of said vertical and horizontal axes,

the engaged narrow faces at the edges of said baflles and shields being correspondingly spherical, and resilient means for pressing said spherical faces into engagement with said-spherical surface to provide a substantially air-tight chamber enclosing said burner.,

11. A machine for tipping ofi exhaust tubes of incandescent electric lamps, comprising a gas inlet block, a gas outlet block depending there- 'from, a pair of bafiles pivoted about an axis,

complementary burner shield portions carried by said baiiies, said baiiles and shield portions being pivotally mounted to, rotate with respect to said blocks about an axis extending at right angles to and intersecting said bailies axis, said baflies, shield portions, and outlet block normally engaging surfaces of'one another to define a chamber, a burner block secured to said outlet block and normally enclosed in said chamber, the surface of said outlet block engaged-by said battles and shields being spherical, with its center disposed approximatelyat the point of intersection of said axes, the narrow faces at the edges ofsaid baffles and shields which engage said outlet block being correspondingly spherical, and means for pressing said spherical faces into engagement with said spherical surface to provide a pressure-holding chamber enclosing said burner.

12. A machine for tipping ofl exhaust tubes of incandescent electric lamps, comprising. a gas inlet block,- a gas outlet block depending therefrom, a pair of baflies, complementary. burner of said outlet block to define a chamber, a burner block secured to said outlet block and normally enclosed in said chamber, the surface of said outlet block engaged by said baflles andshields being spherical, with its center disposed approximately at the-point of intersection of said axes,

the narrow faces at the'edges of said baiiies and shields which engage said outlet block being correspondingly spherical, and means for press- 2,215,100 shield portions carried by said baflles, the ening said spherical faces into engagement with said spherical surface to provide a pressure-holding. chamber enclosing said burner and a portion of an exhaust tube.

.13. The method of sealing a lamp having an exhaust tube, comprising positioning the end portion ofsaid tube in an apertured exhaust rubber, disposing only an intermediate portion of said tube in an enclosed space, evacuating said' lamp, introducing inert gas at a desired pressure above atmospheric through said exhaust tube and into said lamp, admitting gas to said enclosed space to create a pressure therein above atmospheric, and heating said tube in said enclosed space to eflect a tipping ofi operation.

- DANIEL S. GUSTIN.

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