US1971805A - Electrode for stabilizing the cathode spot of mercury arc devices - Google Patents

Description

A llg. 28, 1934. A AMlLLAC 1,971,805

4ELEC'IRODE FOR STABILIZING THE GATHODE SPOT 0F MERCURY ARC DEVICES Filed June-7. 1952 Albert Arnllac, 'IOL MOL/6M JH is Attom-weg.

Patented Aug. Z8, 1934 `FFIC ELECTRODE FOR STABILIZING THE CATH- ODE SPOT OF MERCURY ARC DEVICES York Application June 7, 1932, Serial No. 615,897

In France July 24, 1931 6 Claims. (Cl.` Z50-27.5)

`My invention relates t o the cathodev structure of mercury arc devices, particularly to refractory electrodes mounted in the mercury poo-1 of such devices, and has for its object the provision of an improved electrode arrangement of this character for stabilizing the cathode spot position.

It has already been proposed to maintain in a fixed position the cathode spot of mercury arc rectiers and similar' electrical apparatus by means of a refractory electrode of suitable form,V

composed of tungsten, molybdenum, tantalum, etc., or of various compounds such as borides, silicides'orI metallic carbides. It is known that such stabilization of the cathode spot position insures, in apparatus so characterized, various advantages among which particularly is the possibility 'of i opeartion at a low load and the possibility of reducing, other conditions being equal, the quantity of vapor, of Vmercury or other material, whichV is required in the apparatus. My present invention is directed to an improvement in the means for stabilizing the position of the cathode spot of the apparatus under consideration. This improvement is essentially character,-

2 ized by the fact that cuts,'slits or other capillary spaces are provided in the cathode spot stabilizing electrode. 'I'he invention extends also, in combination with the above first-mentioned means, to complementary means consisting in an increase, with respect to the mass used up to the present, of the mass of the 'cathode-spot stabiliz-` ing electrode and of its thermal conductivity, and

also in an increase with respect to lengthused heretofore, of the .length of the line of stabiliza- 5 tion with respectto the dimensions and mass of the electrode. These two complementary means may be utilized separately or in combination.

The above meansto which my invention is directed increase the stability of the ixing of the cathode spot,`the increase of the mass and of the.

thermal conductivity of the electrode avoiding eX- cessive heating of the electrode and the disappearanceat its surface of the iilm of cathode material, .the existenceof which .is necessary for maintaining the stabilizing effect on the cathode spot position. i i.

My invention will be better understood from the following description when considered in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Figs. 1 and 2 illustrate schematically the position in the cathode container of a vapor electric device such as a mercury arc rectifier, of cathode spot stabilizing 5 electrodes in accordance with my invention; Fig.

3 is a cross-'sectional view of an electrode online 3-3 of Figs. 1 and 2; Fig. 4 is a side elevation of certain of the electrode elements shown in Fig. 3; Fig. 5 is a plan view of the electrode shown in Fig. 3; Fig. 6 is an enlarged View of a portion of Fig.` 5 and illustrates schematically the position of the cathode spot with relation to the stabilizing electrode; and Fig. 7 is a pian view illustrating a modified form of the invention.

In Figs. land 2 the numeral l() designates the cathode container of a mercury arc device such as a rectier and the numeral 11 designates the pool of mercury within the container. In order to maintain the cathode spot of mercury pool 11 in a `fixed position along a predetermined line a stabilizing electrode of refractory material, designated by the lines 12 and 13 in Figs. 1 and 2 respectively, is mounted in thefcontainer 10. The form of this electrode and the manner of mounting thereof in the container will be explained hereinafter.

In the form of the invention illustrated in Figs. 3 to 6, the electrode 12 or 13 of Figs. 1 or 2, for maintainingthe .position of the cathode spot, is constituted by a suitable number of ribbons of refractory metal 14, 15, 16, 17, which are separated from one another by ribbons 18, 19, 20 formed of any suitable metal which is `not attacked by mercury and the thickness of which corresponds to the capillary space which it is desired to establish between the portions 14, 15, 16, 17 of the spot stabilizing electrode. The ribbons 18, 19, 20 are not as high as the ribbons 14 to 17 and do not emerge from the mercury 11. The assembly or unit formed by ribbons 14 to 17 and 18 to 20 is mounted by a member 21 upon a salient portion or rib 22 integral with the wall of the receptacle containing the mercury 11.

In order to eiiect the fixing in position of the cathode spot by capillarity, which is the object of. the invention, the ribbons 14, and 16 of the refractory ribbons 14 to 17 are indented as shown in Fig. 4, and a suitable number of such ribbons according to the maximum rectified current are then pressed against the rib 22, the indented ribbons being in staggered relation or displaced one with respect to another conformably to the arrangement represented in Fig. 5 in which are shown the upwardly projecting portions of ribbons 14', 15 and 16. The inner ribbon, designated in the drawing as 17, is not indented and serves to insure a continuous line of stabilization or iixation of the cathode spot between the various groups of the teeth portions of ribbons 14, 15 and 16, which constitute in eiect a corresponding ccf los

number of spot fixation elements through the eiect of capillarity. At points 23 to 28, as shown in Fig. 6, at the ends of the capillary spaces formed between the adjacent tooth portions of the ribbons 14, 15, 16, and between the ribbons 16 and 17 by the narrow intermediate ribbons, appear regions in which the spot stabilizing `or positioning effect is very pronounced. The ribbon 17, which is not indented insures, as above exof xation corresponds to the dotted lineA 29 shown in the enlarged view, Fig. 6, and enfolds a number of capillary iixationV elements which is proportional to the current supplied by the cathode. The solid or unindented ribbon 17 may advantageously comprise at intervals very narrow vertical slits such as 30 forming so many added points of cathode spot fixation through the effect of capillarity.

Fig. 7 shows a modification of the invention in which the solid or unindented interconnecting electrode element 17 is arranged in the center of groups of indented ribbons to the number of six, 14 to 16 and 31 to 33. In this manner is obtained an improvement on the arrangement shown in Fig. 5 whereby the cathode spot may be maintained in position with the same effectiveness indifferently on one or the other of the groups of surfaces comprised in the arrangement for the fixation of the cathode spot.

Other forms of fixation electrodes may be ernployed in which are provided slits, cuts or other capillary spaces, without departing from the scope of the invention. For example, the electrodes may emerge obliquely from the mercury or, further, may have the form of segments of acylinder the point of emergence of which is substantially tangent to the surface of the mercury.

The cathode spot xation electrodes in accordance with the invention present preferably a continuous line which forms on the cathode surface spiral, zigzag or oblong patterns. Figs. 1 and 2, in which the numerals l2 and 13 represent fixation electrodes forming continuous lines on the cathode surface show schematically two forms of such arrangements.

In the form shown in Fig. 1 the fixation electrode takes the form of a spiral formed by nearly circular elements 34 which are concentric and are interconnected by straight elements 35. The object of this arrangement is to simplify the machining of the ribs formed in the cathode receptacle and against which the xation electrode is pressed.

Fig. 2 shows a zigzag arrangement of the xation electrode which is pressed against parallel ribs provided on the cathode receptacle.

It is to be understood that the schematic iigures of the drawing illustrate various cathode spot fixation electrodes in accordance with my invention and are given by way of examples merely and not as limitations thereof. The particular arrangements which have been described in connection with the figures are to be considered as being contemplated by my invention, it being understood that all equivalent arrangements may be utilized without going beyond the scope of the invention.

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

1,. In a vapor electric device having a liquid cathode, a relatively long and narrow auxiliary electrode horizontally vdisposed throughout its length in said cathode and having portions projecting upwardly from the surface thereof a substantial distance for stabilizing the position of vthe cathode spot on said cathode, said auxiliary electrode including a plurality of relatively thin ribbon members spaced apart throughout their ylength to form capillary spaces therebetween.

2. In a vapor electric device having a liquid cathode, a relatively long and narrow auxiliary electrode horizontally disposed throughout its length with reference to said cathode and having a portion immersed therein for stabilizing the position of the cathode spot thereon, said auxiliary electrode including a plurality of relatively thin ribbon members spaced apart throughout their length to form capillary spaces therebetween, said ribbon members including tooth portions projecting upwardly a substantially distance from the surface ci said cathode.

3. In a vapor electric device having a liquid cathode, an auxiliary electrode immersed in said cathode for stabilizing the position of the cathode spot thereon including a plurality of toothed ribbon members spaced apart throughout their length to form capillary spaces therebetween, the tooth portions of said ribbons being in staggered relation.

4. In a vapor electric device having a liquid cathode, an auxiliary electrode immersed in said cathode forstabilizing the position of the cathode spot thereon including a plurality of ribbon members spaced apart throughout their length to form capillary spaces therebetween, certain of Vsaid ribbon members being toothed, said toothed portions being in staggered relation, one of said ribbon members being substantially continuous.

5. In a vapor electric device having a liquid cathode, an auxiliary electrode immersed in said cathode for stabilizing the position of the cathode spot thereon including a plurality of ribbon members spaced apart throughout the length of said auxiliary' electrode to form capillary spaces between said ribbon members, said auxiliary electrodel being arranged in spiral form in said cathode.

6. In a vapor electric device having a liquid cathode, an auxiliary electrode immersed in said cathode for stabilizing the position of the cathode spoty thereon including a plurality of ribbon members spaced apart throughout the length of said auxiliary electrode to form capillary spaces between said ribbon members, said auxiliary' electrode being arranged in zigzag form f

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