US2679822A - Apparatus for coating hollow glassware - Google Patents

Description

June 1, 1954 R. A. KUEBLER APPARATUS FOR COATING HOLLOW GLASSWARE Filed June 29, 1950 i1llblll IIIIIIIIIIIIIIIIIIIIYIIIII Wm m-Iil Patented June 1, 1954 APPARATUS FOR COATING HOLLOW GLASSWAR-E Robert A. Kuebler, University Heights, Ohio, assignor to General Electric Company, a corporation of New York Application June 29, 1950, Serial No. 171,186

1 Claim.

My invention relates to apparatus for depositing particles of a fume of a radiation-modifying material upon the inner surface of hollow glassware. More particularly, my invention relates to apparatus for creating extremely fine particles of radiation-modifying material and for effecting the immediate deposition thereof upon the inner surface of a hollow glass article such as a lamp bulb. The invention has particular utility in the formation of a fume of light-diffusing particles and the deposition of said particles in a uniform coating over the interior surface of a lamp bulb as broadly disclosed and claimed in patent application serial No. 878, Marvin Pipkin, filed January 7, 1948, now Patent No. 2,545,896 and assigned to the same assignee as this application.

It has been shown heretofore that extremely fine particles of a suitable character to form an almost perfect diffusion material can be created by burning a combustible silicon compound such as ethyl silicate. Such particles can be caused to deposit upon an article directly after formation and are sufficiently adherent to remain fixed to said article during certain uses thereof. The particles can, for instance, be deposited upon the inner surface of an incandescent lamp bulb and will remain in place thereon without further treatment during the operations of making the lamp and during the period of use thereof.

One object of my invention is to provide apparatus for efiectively burning a combustible compound capable of producing a product of extremely fine particle size.

Another object of my invention is to provide apparatus for producing, by burning, a fume of particles of extremely small size within hollow glassware without injury thereto and in a. manner effecting a desired distribution of the particles over the interior surface of the glassware.

Another object of my invention is to provide a burner and associated apparatus for the effective production and distribution of extremely small particles upon the interior surface of hollow articles, which burner and associated apparatus are adapted to extended periods of operation by remaining as free as possible of deposited particles and by being as completely sealed as possible from said particles. To this end, the burner is constructed so as to throw the particles outward therefrom and so as to be readily brushed free of extraneous particles. The associated apparatus is subject to the collection of a much greater deposit of particles and is provided with means for automatically retaining its efiectiveness by cleaning the deposit therefrom.

And still another object of my invention is to provide a burner for effectively producing a radiation-modifying product within hollow glassware from fluid materials combining under certain conditions a very volatile and explosive mixture which burner is particularly adapted to control the mixing and combustion of said fluid materials and which is partiuclarly adapted to prevent the accidental mixing and possible explosion thereof.

A preferred embodiment of my invention provides apparatus for directing a relatively restricted flow of a gaseous combustible material, having a suitable radiation-modifying product of combustion, and a gaseous combustion-supporting material in a manner to support a continuous burning and to develop a substantially uniform outward spread of fume comprised of particles of the product. The apparatus is also preferably adapted to convert the combustible material from a liquid to a gaseous state by the introduction of heat thereinto and, by discharging said combustible material at a lower elevation than the combustion-supporting material, preventing the accidental overflow of the liquid combustible material into the portions of the apparatus containing said combustion-supportmaterial and the development of explosive mixtures in these portions. Apparatus is also provided for holding the hollow glassware and the source of the radiation-modifying material at operative relation and for effecting a suitable relative movement thereof to control the deposition of said material over the surface of the glassware. Apparatus of the above type produces an excess of the radiation-modifying material which is prevented from depositing upon and interfering with the operation of the apparatus by the particular design thereof and by suitable shields and self-cleaning means incorporated therein.

Still other objects and features of my invention will appear from the following detailed description and from the drawing.

In the drawing, Fig. 1 is a vertical section through a burner for developing a source of lightmodifying particles, a holder for supporting a glass bulb in operative relation to the burner, and apparatus for effecting the operation of the burner and holder and for eifecting relative motion therebetween; and Fig. 2 is a perspective view on a larger scale of the burner with certain internal passages therein indicated in dot-dash lines.

The apparatus shown in the drawing provides for the deposition of a light-diffusing material directly on the inner surface of a vitreous bulb l for an electric incandescent lamp immediately upon the formation of said light-diffusing material in the flame of the burner 2. This particularly effective manner of producing and depositing a light-diffusing material corresponds generally to that disclosed in the aforesaid United States patent application of Marvin Pipkin and provides for the ready application of a highly eiflcient light-diffusing material onto the bulb surface in a particularly satisfactory manner. Light-diffusing material applied to a bulb in the prescribed manner is retained by the bulb surface without benefit of a binder.

The bulb l rests in an inverted position on the upstanding collar 3 of the holder 4 surrounding the inner and outer support tubes 5 and B for the burner 2 and is aligned longitudinally with the vertically extending burner 2. The cycle of operation having to do with bulb :l is initiated with the burner 2 at a position immediately above the locating flange or shield on the top edge of collar 3. The bulb l is properly positioned within the apparatus by the engagement of the flange I with the open neck thereof and the seating of the outwardly flared end portion .8 of said neck upon the correspondingly flared portion of the collar 3 and is accordingly aligned and "fixed at an elevation determined by the cooperative functions of said flange 'l and said flared ,portions 8. The relative position of the bulb I within the apparatus-is determined by the holder 4 which is located upon the platform 9 carried by the support columns l0l-!] on the main body H .of saidiholder L During the entire cycle of operation, a relative rotative motion occurs between the bulb i and the burner 2 in that the holder 4 is rotated through a belt !2 engaging a sheave [3 on the lower end of the main body 1! thereof which extends through .and is supported by the bracket M. .A source of energy, not shown, moves the belt 12 at a sufficiently rapid speed to cause a moderate rate of rotation'i-n the bulb '-'l whereby a sufficiently rapid relative movement of the bulbsurface and the burner :2 occurs to neutralize the eifect of any nonuniformdistribution of the light-diffusing material about said burner '2. Support for the apparatus is provided in the bracket M which can be in the form of a stationary table or a turret which is indexed to carry the burner to bulb-loading and other work stations in turn.

The light-diffusing material deposited upon the interior surface of the bulb l is the product of a controlled burning of ethyl silicate vapors in the presence of oxygen and air and first appears in the apparatus in the form of a fume thrown off from the flames 45 over the upper end of said burner 2. Heat absorbed by the burner 2 from the flames 15 causes liquid ethyl silicate located within a relatively large central well it to boil off as a vapor which burns over the upper end thereof. However, comparatively little of the ethyl silicate vapors burn'close to the outer surface of the burner 2 as a series of three outlets l1, l8, and 19 on diametrically opposite sides ofthe central well [6 direct streams of oxygen from the end surface of the burner 2 and the majority of the free ethyl silicate vapors .is sucked into and directed away from the burner 2 by these streams. The three outlets H, .18, and IQ of each group extend from oblique end faces 2ll-29 on the burner 2 at opposite sides of a relatively deep transverse channel 2| thereacross and are accordingly directed across the axis of said burner 2. Each group of outlets l1, l8, and [9 are also offset oppositely from the center of the burner 2 and are inclined oppositely to the faces 2U20 so that the gas streams discharged thereby are directed over different end portions of said burner 2 and passwithout interference from each other toward the opposite bulb wall.

In other words, all the passages l1, l8, l9 in a given one of the two groups are inclined in the same general direction with respect to the vertical axis of the tubes 5, 6 and head 2, and each :group of passages have their axes inclined toward a vertical plane extending through the said vertical axis and through the axis of the channel 2|; the two groups of passages l1, l8, l9 also have their respective axes inclined in opposite directions with respect to a second vertical plane extending through said vertical axis normal to the first-mentioned plane, and the projected axes of respective groups of passages extend across opposite sides of the head 2 without intersecting at any point whereby the two groups project distinct non-intersecting flames which cross .over above the said head.

The manner of directing the flames 15 across the :end of the burner 2 gives a swirling motion thereto .and keeps the higher temperature zone close in around the burner 2 so as to :allow the use thereof within the relatively confining neck portion of the bulb 1 without causing said neck to be heated to .an extent that it cracks or is injured. The outlets IT in opposite halves of the burner 2 .are at somewhat greater inclination to the burner faces 20-20 than the other outlets 1.8 and L9 to cause the outer fringe of the gas discharge therefrom to pass each other without interference and together with said outlets 1-8 and i9 discharge sufficient oxygen to cause separate streams 22 of concentrated f-ume to develo beyond the flames l5. These streams 22 of fume wipe the neck of the bulb I when the burner2 is located adjacent the top of the loeating flange l and are the source of the majority of the light-diffusiI-ig material deposited upon saidneckportion.

The burner 2 is, at all times during the operation of the apparatus, at an elevation determined by the vertical position of the support means comprised of the outer tube -6 and a further extent thereof in the tub 23 which passes down through the main body H of the holder 4 to operating means located below the support bracket 1 4. Overlapping portions of the outer support tube '6 and the tube 23 are fastened together by a screw 24 which also holds the inner support tube 5 in place through engagement with a depression in the side wall thereof. The burner support means includes a sleeve 25 around the tube '23 and is retained by the operating means through engagement with the oxygen connection block 26 which is clamped 'to the lower end of said tube 23.

A second connection block 21 fastened to the bottom surface of connection block 26 prov-idesthe means :of supplying ethyl silicate to the bottom end of the inner support tube 5.

The cycle of operation is initiated with the burner 2 located directly above the top edge of the locating flange "l as, at that time, the lever 28 of the operating means is then at a lowered position in which the roller .29 thereon rides on the low portion 30 of the :camBl :and holds the oxygen connection block 2th to which it is attached by link 32 and the split :collar 33, and the burner assembly at a correspondingly lower position. The burner 2 is not allowed to remain at this position after the start of the cycle because of the relatively restricted bulb area to be coated with the light-diifusing material and is gradually raised to the position shown by rotation of other higher portions 34 and of the cam 3i into 13051- tion below the roller 29. The rate of movement is to a considerable extent determined by the bulb area to be covered by the light-diffusing material at any particular moment; however, said rate must also be less when the burner 2 passes into the upper portion of the bulb as the concentrated streams 22 of the fume do not then wipe the surface thereof and relatively more time must be allowed for said material to deposit fro-m the slower moving fume. The considerably greater area of the upper portion of the bulb l increases the amount of light-diffusion material required in the upper portion 0.? the movement of the burner 2 and said burner 2 is caused to oscillate up and down through a short stroke by the advance of a hollow 36 in the cam 3i into engagement with the roller 29 to provide said additional material. The fume within the bulb 2 takes both a vertical curling motion and a spiralling motion because of the form of the bulb I and the particular direction of the oxygen discharge from the burner 2. Accordingly, all portions of said fume repeatedly wipe or paint the inner sur-- face of said bulb i and produce thereon as uniform a coating of light-diffusing material as possible. The end of the cycle of operation is reached following a gradual lowering movement of the burner 2 during which the concentrated fume streams 22 again impinge upon the bulb neck and deposit a second application of lightdifiusing material directly thereto.

The rates of burning of the ethyl silicate and flow of oxygen are both preferably controlled through adjustments of the sources of supply which are coupled to the connection blocks 27 and 26, respectively, by the pipes 31 and 33, respectively. The flow of ethyl silicate, for instance, is restricted to an amount required to produce the specific coating requirements of the bulb I and accordingly is such as to allow that amount of ethyl silicate to rise to the not top of the burner 2. The ethyl silicate flows from the end of the pipe 37 to a chamber in the center of the connection block 27 and from there passes directly up the hollow center of the inner support tube 5 to the well in the center burner 2. Leakage of the ethyl silicate, which under certain conditions is explosive, is prevented by the packing rings 33 and 4B which are located between the connection block 2'! and the support tube 5 on one hand and between said connection block 2'! and the clean-out plug 4! on the other hand. However, should some leakage occur between the connection blocks 26 and 21, it will be dissipated in the open air since vent grooves 42 between the abutted faces thereof allow it to escape.

Obviously, different operative conditions occur when the apparatus is initially placed in operation at the start of a day since the burner 2 is not then at the elevated temperature it maintains during normal operation. Accordingly, the controls must be adjusted so that less ethyl silicate passes to the burner 2 during the warmingup period to prevent liquid ethyl silicate from flowing out the top of the burner 2. Should the liquid ethyl silicate be fed to the burner 2 at such a rate that it flows out the end of the well I6, no damage can result as it will drain away from well I6 through the channel 2| and will not mix with the oxygen.

It is imperative that the outlets II, I8, and I9 be at a higher elevation than the well I6 to prevent liquid ethyl silicate from flowing in and mixing with the oxygen therein as such a mixture is violently explosive. The oxygen introduced into the apparatus through the pipe 38 enters a chamber in the connection block 26 about the inner support tube 5 and flows upward through the lower end of the tube 23 and thence through the outer support tube 6 to a ring-shaped opening 43 in the burner 2, the lower terminus for the outlets I1, I8, and I9. Although the rate of flow of the oxygen is less critical than that of the ethyl silicate, it must be controlled so that a desired character of silica is formed and so that the extent of the flames I5 and the fume streams 22 will not injure the bulb I and still coat it properly. A deficiency of oxygen is to be avoided since it produces a dense black and streaked coating and permits a considerable deposit of silica to quickly collect on the burner 2 preventing its satisfactory operation. Some deposit does collect upon the burner 2 in normal usage, and it is desirable for said burner 2 to be cleaned with a wire brush at intervals. The design of the burner 2 is such as to collect a minimum amount of fume and such as to be readily cleaned by a brush. Leakage of oxygen from the connection block 26 is prevented by the packing ring 44 between it and the tube 23 and by the packing ring 45 between it and the inner support ring 5.

During the normal operation of the apparatus when a bulb I is in place over the burner 2, a comparatively slow circulation of air and fume occurs from the bulb I through the vent 46 provided between the support collar 3 for said bulb I and the outer support tube 6. This passage of the fume through the vent 46 causes a certain amount of the silica to deposit upon the surfaces of the collar 3 where it could possibly block the free circulation of gases from the bulb I if allowed to build up to any extent. However, scraper 47 at one point on the support tube 6 extends into the vent 46 and sweeps the deposit from the full length of the collar 3 in the course of the rotative motion of said collar 3 and the vertical motion of the support tube 6 in each cycle of operation. The excess silica dislodged from the vent 4t and the fume passing therethrough is thrown clear of the apparatus by the air currents established by the vane 48 on the lower end of the support tube 6. The relative rotation of the collar 3 and the other parts of the holder 4 also creates a mild suction within the vent 46 which assists in withdrawing the fume therethrough and scrapes the deposit of silica that finally collects on the parts within the adjacent area after extended operating periods. A shield 49 and the seal provided by the bellows 50, which rotates with the holder 4 and the sleeve 25, prevent the silica from depositing upon the outer surface of said sleeve 25 and accordingly interfering with theslipping of the said sleeve 25 in the main body I3 of the holder 4 during the vertical movements thereof.

Although a preferred embodiment of my invention is disclosed, it will be understood that the invention, as defined by the claim, can be widely modified within the spirit and scope thereof and is not limited to specific construction and arrangement of parts shown.

What I claim as new and desire to secure by Letters Patent of the United States is:

canvases In apparatus for :coating the interior surfaces of hollow bodies, a liquid fuel burner comprising wen'tically arranged concentric inner and :outer tubes, .a burner :head'mounted on the upper ends of .said tubes and havingan axial vertical aperture itherethrough aligned with the bore of said inner tube and also having an annular portion connected at its periphery "to said outer tube, said head having .a channel extending diametrica-lly across the upper face thereof through :said aperture, a group :of outlet passages in said annular portion of the head at each side of said channel, .said passages communicating at one end with the annular space between said tubes and terminating in orifices at the top of said head above the bottom of said channel, all the passages in a given group being inclined in the same general direction with respect to the vertical axis of said tubes and head, each group of passages having their axes inclined toward a vertical plane extending through said vertical axis and through the axis of said channel, the two groupsof passages also having their respective axes inclined in opposite directions with respect to a secondvertical plane extendingthrough said vertical axis normal to the first-mentioned plane and the proj ectedaxes of respective groups of passages "extending across opposite sides =0! said head without intersecting at any point whereby the two groups project distinct :non intersecting flames which cross over above said head, means to supply liquid fuel through said inner tube to the :aperture in said head, and

means *to supply a combustion-supporting gas through the annular space between said tubes to said passages.

References Cited in the file of this patent UNITED STA'IZES

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