US2401998A - Electrial discharge device - Google Patents

Description

Jne l1, 1946. RH. MLLIAMS ELECTRICAL DISCHARGE DEVICE Filed Jue 19, 1943 Ralph H. wim

BY K

INVENTOR ATTORNEY Patented Juno 11,1946

rs PATENT.

ELECTRICAL DISCHARGE Davies Application lune 19, 1943, Serial Nop 491,742

This invention relates to discharge devices and has particular reference to electrodes therein.

An object of this invention is to provide improved electrode formation and arrangement in discharge devices'.

Another object is to provide an improved 'nuorescent lamp.

Another object is to provide an improved bulbtype fluorescent lamp.

Further objects, advantages and. features will be apparent from the following speciiication taken in conjunction with the accompanying drawing, in which:

Figure l is a perspective view of a lamp embody ing this invention:

Figure 2 is an enlargement of Figure l, broken and cut away to show the electrodes and their eads;

Figure l3 is a view of the electrodes oi Figure 2 showing the form oi anode and the positional relation between anode and cathode; and

Figure t isa schematic operati-ng wiring diagram oi the lamp oi Figures l-.

While this invention may readily be used in e.

variety of discharge devices, the illustrative embodiment herein shown and described comprises a small fluorescent bulb in dimension of the order Acoating gives o@ ultra violet rays.

A particular use for this lamp is in so-caiied black-light arrangements wherein the visible 'rays from the lamp are filtered out and the ultraviolet rays are used to activate visible ray em .1 t-

ing fluorescent material on an obiect,\for example, the dial oi an instrument.

Accordingly, the particular lamp in illustration e o (ci. 17o-12e As irl-Figure l., the ylamp comprises a bulbous glass envelope I, mounted on a brass base sleeve 2 with electrode lead 'contacts 3 and I held in an insulation body 6 which may be glass or other sleeve il and extending to their respectiveco'ntacts t, Il, and t. Mounted on these leads are 'the cathode it and the anode it. Tube it is for evacuation of the\bulb, and for the introduction or argon and mercury.

The cathode i2 is alcoiledwoil type oi tungsten illament coated with barium-strontium oxides as 3@ electron emissive material, heated to emission by current through the iilament; the anode i3 is of molybdenum; and, as shown, the anode is in a plane substantially at right angles to the plane of the lament. The action or the lamp is to heat the cathode to emission and then the lamentcircult is broken externally oi the lamp to induce a discharge from the lament to the anode.

l Figure 3 illustrates the arrangement oi the.

3@ anode i3 and cathode vit with respect to each Within .this loop, the cathode l2 is preferably located adjacent the top, or large portion, for easy starting characteristics, as indicatedA by arrows I5; and relatively distant from the bottom, or small portion for long are, high outputl characteristics as indicated by arrows It. While the utilises an argon, mercury and fluorescent matcrial combination designed to produce a maximum of ultra violet radiation. and a minimum of visible rays. Other combinations may be used as desired, for example, to produce. a maximum of 'visible rays.

This bulb may be simply and easily mounted in or removed yfrom a socket, .lust as an' ifncanu larly at low voltage, high ultra violet output, and

more uniformity and better distribution or arcelcl and ultra violet emanation around the oathing the-cathode,` a

The cathode may, if desired, be locaties-@ise-v where in the anode loop, the controlling charac teristic being that it is effectively surrounded by vthe anode loop. Itis preferably located near the loop in one direction, and distant from the loop in another direction. p

Thus, from lwhatever point on the cathode the varc emission originates, it may travel direct to the anode in an enectively straight line. @lit v l 5@ -As an alternate structure, the anode i3 may be con-V anode must be assembled by insertion through I the small neck of the bulb. A at wire may not be used since it would have an undesirable shadow Thus the anode of this invention is particularly adapted for the lamp. The wire is of small area cross-section to avoid the shadow effect, the loop has a small lateral dimension to permit entry thereof through theneck of the bulb, and is elongated to provide the surface area necessarir to carry the current.

vWhat I claim is:

l. A fluorescent lamp for lowvoltage direct current operation comprising a small bulbous glass envelope with a reduced neck leading to the only entrance .to the lamp; and an anode and a cathode extending into said lamp through said entrance and neck; said cathode comprising a iilamentary electron emissive member extending transversely of the lamp between a pair of uprights;v and said anode comprising an elongated l loop of smallrarea cross-section mounted on a single support beneath said cathode and extendstantially perpendicular to the plane'of sal'd cathode and its supports, in such a mannerl as to contain said cathode adjacent the end of the anode loop furthest in the lamp.

2. A fluorescent lamp constructed for negative glow operation comprising a small envelope of Ibulbous form having areduced neck portion, a base secured to its neck portion, a pair of lead -wires extending into the envelope from said base, a substantially straight filamentary electron emis- -sive cathode extending transversely of ythe envelope and secured at its ends to said lead Wires, an anode comprising a flat elongated loop of wire presenting an upper portion circular in form and disposed concentric with and in a plane perpendicular to said cathode the remaining portion of the anode being relatively distant from the `ing longitudinalls'lof saidv lamp in a Plane subcathode extending toward and supported from

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