US2232816A - Electric lamp - Google Patents

Description

Feb. 25, 1941. V N HORN 2,232,816

ELECTRIC LAMP Filed Jan. 19, 1940 FIE. 1. H

20 I ll /9--" ii? I 7 F ii: 2/

v Inventor:

Irving H. VanHorn,

is Attorney.

, Patented Feb. 25, 1941 PATENT OFFIQCEY nmcrnro LAMP Irving B. Van Horn, East Cleveland, Ohio, as-

signor to General Electric Company, a corporation of New Ycrh Application as, 19, 1940, Serial No. 314,640 Claims. (01. 176-34) My invention relates in general to. electric incandescent lamps comprising a sealed bulb containing a filament adapted to operate at a high temperature. More particularly, my invention 5 relates to a heat protective arrangement for such lamps.

In the operation of electric incandescent lamps of the high wattage type, various P s of the lamp, such as the bulb wall, stem, and the base,

to are heated to very high temperatures by the heat radiated by the filament. This is particularly true in reflecting ineandescentlamps of the type in which the side wallportion of the bulb is formed as a reflecting surface and the highlli wattage filament is mounted in relatively close relation to that portion of the bulb wall adjacent ,the bulk neck, such a filament location being necessitated by optical requirements. When such lamps are burned in a base-up position, the neck and adjacent portions of the bulb wall are apt to be heated to such a high temperature as to cause a cracking of the glass. Furthermore, the excessive heat in the neck portion of the bulb may prove to be injurious to the lamp base and in some cases even to the lamp socket.

One object otmy invention is to provide an electric incandescent lamp with a heat protecting device for shielding the bulb neck and lamp base from the heat radiated by the lamp filament.

80 Another object of my invention is to provide Still another object of my invention is to provide a relatively high-wattage reflecting type incandescent lamp employing a relatively small sized envelope.

A feature of the invention is the provision of a disc of insulating material in the neck ofrthe bulb between the lamp m and the filament togather with a wire screen element of cylindrical shape secured to the periphery of the insulating disc and extending longitudinally of the bulb neck to a point a relatively slight distance below the filament. g

Further objects and advantages of my invention will appear from the following detailed descriptlon' of a species thereof and from the ac comp ny s drawing in which; I

Fig. 1 is an elevation, 'partlyin section, of an 60 electric incandescent lamp comprising my invention; and Fig. 2 is a perspective view or the lamp as to the invention comprises a hermetically sealed bulb It containing a gas filling such'cs nitrogen, argon 'or other suitable gas, and having a neck portion H and a base l2 secured to said neck portion. The base may be of the conventional screw-threaded or any other suitable type. The bulb proper is formed with a flattened top porticn l3 having a curvature of relatively large radius and a reflecting side wall portion l4 shaped to conform to a surface of any desired optical reflecting'shape such as, for instance, a m

itinuing for a short distance along the said neck. The flattened top portion i3 is left clear for' the transmission of the light rays therethrough. The

inner surface of the bulb, including thegreater portion of the bulb neck, is preferably formed with a light frost. .As a result, the light rays transmitted through the top portion it are somewhat diilused.

Mounted within the bulb it symmetrically about the focal point or optical center of the refiecting suriace It is an electric energy translation element or filament it or a refractory metal, preferably tungsten. This filament preferably comprises a coil formed into a i -shape with the plane of the V extending transversely of the iongitudinal axis 01' the bulb. The filament is of relativelyhigh wattage such as, for instance, 300 watts or higher, and is supported at its ends by a pair oileading-in wires l1, l8 preferably of nickel. These leading-in wires are sealed in the pres portion 2b of an inwardly extending stem l9 and are soldered or otherwise secured to the base shell 2| and eyelet 22. The V-shaped filament is further. supported at its mid-point or 40 apex by a support wire 23 the lower end or which is. embedded in a button lot-med at the upper end of a glass arbor v25 extending upwardly from the stempress 20. v Motmted within the neck ll of the bulb be- 46 a substantially cylindrical metal shieldor wire 50 screen member '21 disposed substantially concentrically within the bulb neck H. The disc 26 is preferably made of a ceramic material commerically known as Alsimag, but it may be made'ot any ceramic possessing iairstrength'and 6t characterized by freedom frommoisture, such as centrically within the bulb neck just above the button 24 on the glass arbor 25, and is supported in such position by two support wires 28, 29 and also by the filament support wire 23. The disc support wires 28, 29 are embedded at one end in the glass button 24 and extend laterally therefrom. At their outer ends, the said disc support wires are bent around the edge or periphery of I the ceramic disc, as shown at 30, so as to rigidly .clamp the same. The filament support wire 23 is formed with a laterally extending bent portion 3| (Fig. 2) which likewise clamps around the edge of the ceramic disc 26. The three supports 23, 28 and 29 for the disc 26 are arranged approximately 120 apart so'as to support the disc at equally spaced points around its periphery. To prevent rotation of the ,disc, the periphery thereof is provided with notches 32 into which the support wires 23, 28 and 29 extend. The disc 26 is further provided with a pair of openings 33, 33

through which the leading-in wires l1, l8 extend.

The cylindrical shield or wire screen member 21 surrounds the ceramic disc 26 and extends from a point just below the filament l6 to a point opposite the stem press or thereabouts. This screen member is secured, at a point intermediate its length, to 'the periphery of the ceramic disc 26. For this purpose, the inner surface of they screen member 21 is formed with an annular groove 35 which receives the edge of the ceramic disc'fit. The wire screen member is made of suitable material, such as nickel wire, and with suitably sized mesh openings, such as, for'instance, 20 per inch. The cylindrical screen member is formed from a fiat screen which is first provided with the groove The ceramic disc 26 serves primarily as a heat deflector to shield the bulk neck I I, glass stem an,

the lamp base I2, and even the associated lamp socket, from the heat radiations of the filament when the lamp is burned in a base-up position- Furthermore, the disc 26, being made of a ceramic material white in appearance, also serves as a. light reflector to redirect forwardly into the beam all those rays from the filament which would otherwise pass out through the bulb neck and be lost. In this manner, undesirable back-light through the uncoated portion of the bulb neck up the hot gas convection currents within the I bulb and efiectively maintains the neck and adjacent side wall portions 35 of the bulb at permissible temperatures. Without the' wire screen member, the heat rays from the filament would be deflected by the ceramic disc 26 against the bulb neck II at points closely adjacent the periphery ofthe disc, thus causing intense localized heating of the glass at such points. Such an intense localized heating would cause the reflecting coating IE to burn at suchpoints and so present an unsightly appearance, or it may result in the cracking of the glass. Consequently, the wire screen member must be employed in conjunction with, and inaddition to, the ceramic disc 26 in order to obtain eflective protection of both the bulb and the reflecting coating from the heat radiations.

small sized bulb for lamps of relatively high wattage.

To enable the cylindrical wire screen member 21 and the refractory disc 26 to eifectively per- Because of such eil'ectlve protection,

it is therefore possible --to,employ a-relatively form their .heat protective functions, they must be of adequate size in relation to the bulb neck and the lamp filament. The disc 26 should be made of a diameter approximating that of the bulb neck so that it extends across substantially the entire space within the bulb neck and substantially closes oil the same, but with its periphery slightly spaced from the inner surface of the'bulb neck. The cylindrical wire screen member 21 should be of such a diameter'that, if extended, it would enclose the filament l6 as well as the leading-in wires l1, l6 and support wire 23. In other words, the cylindrical screen member, mounted concentrically within the bulb neck, should be of such a diameter that the lateral location of any given element of its surfacewill lie intermediate the centrally mounted filament and the bulb neck wall. In addition, the wire screen member 21 should be of sumcient length, i. e., should extend a sufiicient distance towards the filament id to more or less shield from the filament the relatively sharp-curved joining portions 35 of the bulb joining the bulb neck and side wall portions H and M, respectively. Such reversely curved joining portions are of little assistance in the production of the resultant light beam so that the interposition of the wire screen between the filament and such relatively inefiective joining-portions 36 does not cause any appreciable loss in the intensity of the projected beam. With the particular arrangement shown in the drawings, the wire screen member 2? and ceramic disc 26 together function as a heat protective device or shield not only when the lamp is burned in a vertical base-up position, but even when the lamp is tilted to a position at an appreciable angle from vertical base-up position, such as or thereabouts. v

In addition to its function as a heat protecting device, the wire screerr' member 21 also serves as an eifective blackening collector when the lamp is burned in a position approximating a base-up position. The wire screen collects a considerable percentage of the filament particles vaporized oi the filament during operation which might otherwise be deposited on the-bulb wall. Thus, blackening of the bulb is materially reduced with consequent maintenance of lamp efiiciency for a longer period of time.

Although I prefer to employ a wire screen for the purpose of protecting the bulb neck and adjacent portions of the bulb side wall from the heat radiated by the filament, other suitable means may be employed if desired. Thus a solid metal shield in the shape of a. cup may be mounted on the ceramic disc 26 so as to face the filament It. In such case, the metal cup is preferably made of a material having a surface which will reflect light so that the metal cup has the 7 additional function of a light reflector.

While such a'metal cup is effective .in preventing overheating and cracking of the glass bulb, it does not diflfuse the hot gases within the bulb or collect the blackening particles as efiectively as does the wire screen member 21.

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

1. An electric incandescent lamp comprising a sealed glass bulb containing a gas fllling and having a neck portion, an electric energy translation element of relatively high wattage mount-' ed within said bulb in relatively close relation to said neck portion and normally causing overheating of said neck portion, and a heat protective device mounted within said bulb to de- 'flect'and diffuse the hot gas currents therein,

said device comprising a disc of refractory material mounted centrally'within said neck portion and extending transversely thereof, said disc deflecting the hot gas currents away from said neck portion, and a cylindrical wire screen member disposed substantially cencentrically within said bulb neck and extending between said disc and said translation element. said wire screen member being arranged to diffuse the hot gas currents within said neck portion and prevent over-heating thereof.

2. A reflecting electric incandescent lamp comprising a sealed glass bulb containing a gas filling and having a side wall portion and a neck porthe hot gas currents away from said neck portion, and a cylindrical wire screen member disposed substantially concentrically within said bulb neck and extending between said disc and said translation element, said wire screen member being arranged to diffuse the hot gas currents within said neck portion and prevent over-" heating oi the said neck portion and the reflecting coating thereon.

8. A reflecting electric incandescent lamp comprising a sealed glass bulb having a side wall portion and a neck portion, a continuous reflecting coating on the inner surface of said side wall and neck portions-an electric energy translation element of relatively high wattage mounted within said bulb in relatively close relation to said neck portion and normally causing overheating of said neck and adjacent side wall portions, and a heat protective device mounted 7 within said bulb to deflect and difluse the hot. gas currents therein, said device comprising a aesaerc i 3 'reflectingdisc of refractory material mounted centrally within said neck portion and substantially closing ed the same, and a cylindrical wire trically within said bulb neck and extending between said disc and said translation element. said cylindrical wire screen member being oi approximately-the same diameter as said disc with its upper edge located a relatively slight distance below said translation element.

4. ;A reflecting electric incandescent lamp comprising a sealed glass bulb containing a gas filling and having a side wall portion and a neck portion, a continuous reflecting coating on the inner surface of said side wall and neck portions, an electric energy translation element of relatively high wattage mounted within said bulb in rela tively close relation to said neck portion and normally causing overheating of said neck and adjacent side wall portions, and a heat protective device mounted within said bulb to deflect and diffuse the hot gas currents therein, said device I comprising a disc of refractory material mounted centrally within said neck portion and extending transversely thereof, said disc deflecting the hot gas currents away from said neck portion, and a cylindrical wire screen member surrounding said disc and secured to the periphery thereof, said wire screen member extending from said disc towards said translation element, the upper edge of said wire screen member being located a relatively slight distance below said translation element. 4

5. A reflecting electric incandescent lamp comprising a sealed glass bulb containing a gas filling and having a side wall portion, a neck portion, and an inwardly projecting stem in said neck portion, a continuous reflecting coating on the inner surface of said side 'wall and neck portions, a glass arbor extending longitudinally of said bulb from the inner end of said stem, an electric energy translation element of relatively high wattage mounted within said bulb in relatively close relation to said neck portion and normally causing overheating of said neck and adjacent side wall portions, and a heat protective device mounted within said bulb to deflect and diffuse the hot gas currents therein, said device comprising a reflecting disc of reiractorymaterial mounted centrally within said neck portion and substantially closing off the same, said disc being supported by a plurality of support wires embedded ln said glass arbor, and a cylindrical wire screen member disposed substantially concentrically within said bulb neck and extending between said disc and said translation element, said cylindrical wire screen member being of approximately the same diameteras said disc and being secured to'the periphery thereof, the Upp r edge oi said wire screen member terminating a relatively slight distance below said translation element.

IRVING- H. VAN HORN.

CERTIFICATE OF CORRECTION.

Patent No. 2,252,816. February 2 1911;.-

IRVING a. VAN 110m.

It is hereby certified that error appears inthe printed specification of the aboire nmdbered patent requiring correction'es follovia Page 5 first column, line 514., claim-5, after the herd 'bulb" insert "containing a gas filling and-- and that the said Letters Pateilt should be read with this correction therein that the same may conform to the record of the case in the Patent Office. X

Signed and sealed this 25th day of March, A. b. -19L1.

-fien ry van Arsdale, Actitig Commissioner of Patents.

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