US2617065A - Vapor-electric device - Google Patents

Description

Patented Nov. 4, 1952 VAPOR-ELECTRIC DEVICE Gerhard Lewin, Maplewood, N. J., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application October 14, 1950, Serial No. 190,141

7 Claims. 1

The invention relates to vapor-electric devices such as are generally known as ignitrons.

Attempts have heretofore been made to provide a semi-solid or sponge cathode for electric discharge devices, and the present invention contemplates improvement thereover.

In the broad aspect of the invention, more stable and unfailing arc discharge is an objective and accomplished result thereof.

The invention also provides for more certain supply of the mercury or other reconstructive cathode material to the surface where the arc is instigated.

A further object of the invention is to provide a cathode body not readily poisoned during fabrication and/or operation of the ignitron.

Another object of the invention is to provide a cathode body of a character not affected adversely by standby periods and which will resume operation at any time desired without missing.

Other objects of the invention will appear to those skilled in the art to which the invention appertains as the description proceeds, both by direct reference thereto and by implication from the context.

Referring to the accompanying drawing, in which like numerals of reference indicate the same parts in both views thereof:

Fig. 1 is a central longitudinal sectional view of an ignitron of arbitrarily selected construction showing my invention embodied therein; and

Fig. 2 is a cross-section on line lI-II of Fig. 1.

In the specific embodiment of the invention and associated ignitron construction illustrated in the drawing, but without limiting to the details thereof, a cylindrical casing I of steel or other sturdy material is shown having a bottom 12 integral therewith and a top header I3 sealed at the upper rim of said casing to provide a closed envelope adapted to be evacuated.

The particular header shown, provides appropriate lead-in seals l4, 5 for electrode leads l6, l1 respectively for an anode I3 and ignitor 19 within the casing and supported from said header by said leads. The lead-in seals each include a glass or other insulating sleeve 20 by which the leads are kept electrically distinct from each other and from the casing. The anode I8 is located toward the top of the casing, well above the bottom wall l2, whereas the ignitor I9 is located below the anode, prefer-ably centrally of the casing, and is directed toward and terminates at its bottom in the vicinity of said bottom wall. Said ignitor is shown as relatively slender and tapers downwardly, with its bottom end quite small. Said ignitor may be composed of materials as used for ignitors of the prior art. or may be of such other material or materials adapting it more especially to the present invention.

A sponge cathode, designated generally by'numeral 2|, is provided in said container and is of pan-cake shape, and situated upon the bottom wall 12 of the ignitron, preferably fitting the container at its periphery and frictionally or otherwise held permanently in fixed position. The aforementioned lower small end of the isnitor l9 rests upon the upper surface of the sponge cathode 2| in constant contact therewith, and as one means for maintaining such contact without detriment to the lead-in seal I5, the leadin I! for the ignitor, between the seal and the ignitor, is shown with a transversely extending section 22 which, with the rest of said lead-in, possesses adequate resiliency, supplemented by the weight of.the ignitor, to accomplish the purpose. The ignitor projects, from its contact on the sponge cathode, at right angles thereto and in a direction longitudinally of the casing. Mercury or other reconstructing liquid cathode material is applied to the sponge cathode 2| to the extent that said sponge will absorb the mercury or the like without any excess remaining on the surface. One manner of thus charging the sponge body with mercury is to cleanse the sponge material until sufficiently clean to be wetted by mercury and then apply an excessive amount of mercury in the casing, whereupon the sponge will immediately fill with mercury, after which the free mercury which is not absorbed into the sponge can be poured oiT. The sponge cathode 2|, with the absorbed mercury, constitutes the cathode of the ignitron.

According to the present invention, the sponge cathode 2| is constructed essentially of two different materials, of which one is usedto take advantage of its relatively large interstices between granules for providing generous reservoir capacity, and also to take advantage of its characteristic of ailinity for and absorption of the mercury coming in contact therewith. Selection of the other essential material to constitute the sponge cathode is for purposes of providing an arc-strikin surface generously supplied by capillarity through said material with mercury or the like, and to take advantage of resistance of this other sponge material to contamination or poisoning thereof during either fabrication procedure or during operation. More specifically, the present invention proposes for cathode 2| use of a body portion 23 essentially of sintered iron or other material having high absorptive afiinity for the reconstructing cathode fluid, such as the cury above mentioned, and an arc-striking portion 24 essentially a sintered metal of the platinum group of elements. Both platinum and ruthenium have proven to be excellent metals of this group for the purpose, and of these, I select ruthenium as preferable. I have discovered that these platinum group metals, and ruthenium in particular, are exceptionally well suited as arestriking materials, as they are easily wetted by mercury; show no adverse effects, mechanical or chemical, from use with or from components of the usual ignitor generally employed in ignitrons; possess noteworthy smooth operation; and exhibit little, if any, evidence of sputtering in use in the ignitron. A further and highly important advantage of use of the metals of the platinum group, with emphasis on the use of ruthenium as the preferred material, is that, even after long stand-by periods or intervals of non-use of the ignitron, there is no skipping or missing of the arc in striking instantly and invariably as required, and which is one of the drawbacks of molybdenum previously proposed in the art for a cathode material.

In the specific disclosure arbitrarily selected for illustration in the drawing, the bod portion 23 of the sponge cathode is shown relatively flat or thin, of pan-cake shape to fit within the bottom portion of the container fiatwise on the bottom wall thereof and frictionally or otherwise held fixed in that position. The arc-striking portion 24 is shown as a smaller disc than said body portion and embedded therein concentric thereto and according to the present illustration the upper faces of the said body portion and arc-striking portion are in a common plane. The arcstrikin portion is thinner than the body portion so that a part of said body portion underlies the arc-striking portion and provides a copious supply of mercury or the like to said arcstriking portion and by capillary action through the arc-striking portion the mercury is ever present at the arc-striking surface. As the ruthenium, or its equivalent from the platinum group, has the beneficial characteristic of not drying up or of becoming non-wettable by mercury, the result is obtained of mercury always being present at the arc-striking surface and being invariably in condition for arc-striking continuously, repetitiously,or-occasionally as desired or required.

Finally, it may be pointed out that the body portion 23 of compressed sintered granules essentially iron, is employed in conjunction with the centrally disposed arc-striking portion 24 of compressed sintered granules essentially of the platinum group metal, to take advantage of the inherent characteristic of the iron sponge of more active absorption of mercury coming in contact therewith than would occur with a similarly compressed sintered body of metal of the platinum group. In view of the high cost of metals of the platinum group, the selected metal, in powder form, may be mixed with a less expensive metal or non-metal, also in powder form, to serve as a filler, and such metals as molybdenum and tungsten and non-metals such as ceramics, may thus be employed to help obtain desired volume or dimensions of the arc-striking portion 24, but with said portion still essentially metal of the platinum group .The powder employed, whether soleis a platinum group metal or a mechanical mixture with other materials, is compressed and sintered and juxtaposed to the body portion 23, which likewise, while preferably a compressed and sintered iron sponge, may be a mechanical mixture of which iron constitutes the essential ingredient.

An ignitron in use will condense mercury vapor on the side walls of the container, and that condensation forms in drops which run down the wall and lodge upon the sponge cathode surface. By the provision of a sponge of sintered iron or the like in the vicinity of the side wall of the container, said surface will be in appropriate location to receive and absorb the drops of mercury and thereby avoid flow of mercury over the cen tral arc-striking surface portion. That mercury is delivered back to the arc-striking portion 24 to the upper surface thereof and thus repetitiously used. The arc-striking portion composed essentially of ruthenium or the like, is inherently closer grained and has smaller interstices than in the iron or other sponge material of the body portion, and has the desired characteristic of rapid transition by capillarity of the mercury copiously fed thereto by the sponge body portion.

I claim:

1. A vapor-electric device comprising a sealed container havin an anode therein, a sponge cathode fixed in said container, said sponge cathode comprising a sponge material receptive of condensed cathode material flowing thereto down the side wall of the container, and an arc-striking portion spaced away from said side wall and juxtaposed to said sponge material, said arc-striking portion having an arc-striking surface essentially of a metal of the platinum group, an ignitor in said casing in contact with said arcstriking surface, and reconstructing cathode material absorbed in said sponge material.

2. A vapor-electric device comprising a sealed container having an anode therein, a sponge cathode fixed in said container, said sponge cathode comprising a sponge body portion and a sponge arc-striking portion juxtaposed to the body portion, said arc-striking portion having an arc-striking surface essentially of ruthenium, an ignitor in said casing in contact with said arcstriking surface, and reconstructing cathode material absorbed and constantly present in said sponge cathode.

3. A sponge cathode for a vapor-electric device, comprising a body portion characterized by affinity to absorption of a reconstructing cathode material, and an arc-striking portion juxtaposed to the body portion and composed essentially of a metal of the platinum group.

4.. A sponge cathode for a vapor-electric device, comprising a body portion characterized by affinity to absorption of a reconstruction cathode material, and an arc-striking portion essentially of ruthenium juxtaposed to the body portion.

5. A sponge cathode for a vapor-electric device, comprising a body portion characterized by aflinity to absorption of a reconstructing cathode material, and an arc-striking portion essentially of platinum juxtaposed to the body portion.

6. A sponge cathode for a vapor-electric device, comprising a body portion characterized by affinity to absorption of a reconstructing cathode material, and an arc-striking portion essentially of compressed granules of sintered metal of the platinum group.

7. A sponge cathode for a vapor-electric device, comprisin juxtaposed portions of difierent sponge materials of which the material for one 5 6 of said portions is essentially a. metal of the UNITED STATES PATENTS platinum group. Number Name Date 2,128,861 Tonks Aug. so, 1938 GERHARD 5 2,169,032 Slepian Aug. 8, 19 9 2,218,386 Smith Oct. 15,4240 REFERENCES CITED 2,432,513 Depew Dec. 1e,-;-1947* The following references are of record in the 2,463,037 Clark Apr. 26.11949 file. of this patent: f

Claims (1)

1. A VAPOR-ELECTRIC DEVICE COMPRISING A SEALED CONTAINER HAVING AN ANODE THEREIN, A SPONGE CATHODE FIXED IN SAID CONTAINER, SAID SPONGE CATHODE COMPRISING A SPONGE MATERIAL RECEPTIVE OF CONDENSED CATHODE MATERIAL FLOWING THERETO DOWN THE SIDE WALL OF THE CONTAINER, AND AN ARC-STRIKING PORTION SPACED AWAY FROM SAID SIDE WALL AND JUXTAPOSED TO SAID SPONGE MATERIAL, SAID ARC-STRIK-

Images