US2121615A - Gas or vapor filled discharge device - Google Patents

Description

June 21, 1938. H. VATTER GAS OR VAPOR FILLED DISCHARGE DEVICE Filed Sept. 30, 1936 INVENTOR Hans Va 7fe/" BY M WITNESSES:

Patented June 21, 1938 UNITED STATES PATENT E assignor t Siemens schaft, Siemensstadt,

& Halske, Aktiengesellnear Berlin, Germany, a

corporation of Germany Application September 30, 1936, Serial No. 103,297

In Germany 3 Claims.

My invention relates to electrode structure, and especially to electrode structure for gas or vapor filled discharge devices.

An object of the invention is to provide a cathode structure that will permit a quick change from a glow to an arc discharge at comparatively small current strengths.

It is well known that in a gas or vapor filled discharge device the discharge first becomes a glow type which is later transformed into an arc type of discharge in most cases the smallest arc current magnitude is considerably larger than the current magnitude of the glow discharge. It is desired to provide a special type of electrode for causing the arc discharge to be established quickly at comparatively small current strengths.

Other objects and advantages of the invention will be apparent from the following description in conjunction with the accompanying drawing in which the figure illustrates a discharge device with a preferred embodiment of the electrode structure.

In its specific embodiment, my electrode structure has two portions, one of which III has the 5 large surface which may be, as illustrated, the bottom of an inverted cup. This large active surface portion has preferably a central opening II therein through which projects a stem I2 having on its projecting portion a pointed por- 30 tion I3. This stem is connected at I4 to the cup supporting the other portion II] of the electrode structure at a considerable distance from the pointed end I3. The continued extension I5 of this stem I2 may be utilized as a lead support 35 and there may be ad 'tional supporting elements such as the stem I6.

The complete device, of course, includes at least one other cooperating main electrode and, if desired, control and auxiliary electrodes of 40 any desired shape and arrangement.

In the operation of the device, the glow discharge heats the projecting point to a high temperature and thus makes possible the speedy transition to an arc type of discharge that will 5 spread to the'large active surface of the portion II). The higher temperature of the point depends upon the fact that effective heat conduction can only take place from the point along the wire 6 and as this is only a small surface, the radiation loss is as small as possible. This heat transference from the pointed portion I3 may be minimized in various ways if desired.

The portion I2 may be of poor heat conducting material or may be designed with a very small October 5, 1935 cross section intermediate the pointed portion I3 and the connecting place I4 to the large surface electrode portion ID. This connecting portion may, for example, be of a small tungsten wire coated with insulation such as glass or porcelain. The intermediate portion I2 might contain a section of graphite that would conduct electricity readily, but not heat.

The point I3 may have a diameter of about 1 millimeter and preferably projects only but onehalf millimeter above the surface.

The pointed portion I3 may, of course, be constructed if desired of material that would readily start the discharge such as nickel, tungsten, or other materials with caesium, barium, thorium incorporated therein or on its surface.

While a specific embodiment of the invention has been disclosed, it is apparent that many modifications thereof are possible. Accordingly the appended claims are not to be limited except insofar as is necess'tated by the prior art.

I claim as my invention:

1. An electrical discharge device comprising a container, a gaseous atmosphere therein, an anode and a cathode structure within said container, said cathode structure having a large surface facing said anode and having an opening therein, a stem of said cathode structure projecting through the opening in said surface, said stem and said large surface being connected together away from the discharge space between said anode and cathode.

2. An electrical discharge device comprising a container, a gaseous atmosphere therein, an anode and a cathode structure within said container, said cathode structure comprising a cupshaped portion and a stem portion, said cupshaped portion having a surface facing said anode with a rim portion extending away from said anode, said stem portion projecting through an opening in the surface of said cup-shaped portion.

3. An electrical discharge device comprising a container, a gaseous atmosphere therein, an anode and a cathode structure within said container, said cathode structure comprising a cupshaped portion and a stem portion, said cupshaped portion having a surface facing said anode with a rim portion extending away from said anode, said stem portion projecting through an opening in the surface of said cup-shaped portion, and connected to the inner side of said rim portion.

HANS VA'ITER.

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