US1774109A - Electric switch - Google Patents

Description

' L. A. M. PHELAN ELECTRIC SWITCH 01-1 mm Filed Dec. 22. 1925 New vim mated Aug. 25, 1930 UNITED STATES PATENT" OFFICE tours a m. PHELAN, or mnsa'r, mnm m, assxdnoa, BY MESNE assremrmws, 'ro 'rnm-o-smr comraors comrmw, or nnxmnr, nwnmna, A coarona'non ELECTRIC SWITCH a ncama med December 22, 1926, ser'miimisaua Renewed January 6, 1930;

electrical circuit an extraordinary number of times without undergoing substantial, deterioration or disintegration.-

' A further object of this invention is to provide an electrical contactor switch in which the electrodes are made of difi'erent materials in order to control the movement of the body of the current-conducting fluid, such as mercury, under certain predetermined conditions'.

A still further object of this inventionis to provide an electric contactor as referred to above in which one electrode is so constructed, and the materials com risin that electrode are so selected, that a Elm 0% mencu ry will adhere to said electrode and cause a make and break to occur between twomercury bodies, that is to say, the main body of merlcury and the film adhering to the electro e.

Further objects will be aipparent from the description and drawings orming apart of this specification to which reference may now be had for a more complete understandm of the characteristic features of this invention,

modified form of one of the electrodes com prised in Fig. 1 j

Fig.4 is a dia ammatic view illustrating the method in w ch a body of mercury in a contactor breaks at an electrode having a lower rounded end; and

Fig. 5 is a diagrammatic view illustrating the method in which a body of mercury in a contactor may break from an electrode which is provided with a core made of a material to which the mercury adheres with some tenacity.

Referring more particularly to the drawings, the contactor comprises a container 10 in which two spaced electrodes 11 and 12 are hermetically sealed. The electrodes 11 and 12 are shown asdisposed adjacent one end of the tube, and fixed to supporting members 13 and 14. The supporting members are, in turn, connectedto leading-in-wires 15 and 16 respectively, which provide means for electrically connecting the electrodes 11 and 12 to. their respective accessible terminals 17 and 18. A bodyof mercury 19 is also disposed within the containerlO and serves to bridge the electrodes 11 and 12. Thus, under certain conditions, such as by tilting the contactor, .anelectrical circuit is .established through the contactor.

The container 10 may be made. of glass of :the quality usually employed in manufac turin incandescent lamp bulbs, etc., or it may e made of either pyrex or'boro-silicate glass. When the contalner is made of lass such as is usually employed for bulbs an the like, the leading-in-wires 15 and 16 are preferably made of a suitable wire, that is, one thatwillinsure theretention of permanent hermetic. seals for the container; this latter being necessary, for instance, when the seals become heated, or when substantially high currents are handled by the contactor.

A well known sealing-in-wire is known in the trade as Dumet which consists of an exterior copper coating over a nickel-iron alloy. If, however, the container be made of pyrex or boro-s'ilicate" glass, the leading-in-wires w leading-in-wires situated in the interior of the container. These supporting members may be made of a non-deteriorating or inert metal such as iron.

In order to maintain the interior of the container 10 inert to the material entering into the construction thereof, the atmospheric air is evacuated from the container to a substantially high degree and is then filled with an inert gas, such as hydrogen, to a pressure approximating atmospheric pressure. By this means of filling the container with an inert gas, and further, by properly selecting the materials exposed within the interior of the container, deterioration and disintegration of the contactor are greatly reduced when said contactor is subjected to severe service conditions.

The electrodes 11 and 12 are of difierent construction. The electrode 12 is made of any suitable material preferably of ironchromium alloy or iron alone, while the electrode 11 may be made of monel or, as illustrated in Fig. 2 of the drawing, may comprise a main body portion 21 which may be made of iron or an iron chromium alloy hav ing a .central core 22 made of monel.

When the electrode 11 consists of a plurality of portions all made of different materials, the body portion 21 is preferably made of a metal such as an iron chromium alloy or chromium steel alloy which does not disintegrate or deteriorate rapidly when subjected to an electric arc, however, this portion may also be-made of tungsten, molybdenum, or the like. When the said body portion 21 is made of the materials mentioned above it does not readily amalgamate with or become wetted by the mercury and, therefore, only a small film, if any, of mercury adheres to the body portion21.

The core 22, which is made of Monel metal, constitutes a metal that readily amalgamates or wets with the mercury so that when the meniscus of mercury recedes from the electrode, a small drop or body 23 of mercury will adhere to the core portion 22. This body of mercury 23 adheres tenaciously to the core because of the amalgamation therewith and the mercury. This insures, in subsequent breaks between the electrodes and the meniscus of mercury, that the breaks in the electric current or the arcs will occur between the main body of mercury in the contactor and the film or drop 23 which adheres to the electrode core 51.

In a modified form, as shown in Fig. 3, the main body portion 24 may preferably be made of an iron chromium alloy or of any of the metals mentioned above, and the core 25 may be made of Monel metal to which mercury will readily adhere. The lower portion of the electrode is rounded oft as shown at 26 in order to prevent the formation of any sharp corners or edges which would tend to deteriorate and disintegrate in the event that the electric arcs occurred adjacent to them. A body of mercury 27 will adhere to the monel core 25 for the same reason, as illustrated in Fig. 2. The concavity or recessed portion 28 of the electrode 24 tends to cause a body of mercury 27 to adhere with a high degree of tenacity to the core 25. In both the electrodes of Figs. 2 and 3 the supporting members may beinserted into openings 29 and 30 respectively.

As concerns the action of the meniscus mercury in relation to the electrodes where the electric arcs are broken when the contactor is moved to open circuit position, reference may be had first to Fig. 4 wherein an electrode 31 having a lower rounded end is shown in contact with a body of mercury 32, the mercury being shown as receding from said electrode just prior to the breaking of the circuit. If the entire body of the electrode 31 is made of iron or an iron chromium alloy, the mercury film formed thereupon is insufficient to cause any substantial or effective portion of the mercury body 32 to adhere thereto in opposition to the cohering force which exists in situ in the mass of the meniscus of mercury 31. As the circuit is being broken, a very small thread of mercury 33 connects the main body of mercury 32 to the electrode 31, and when this thread breaks the direct and intimate contact between the electrode 31 and the mercury 32, an arc will occur at the surface of said electrode and, if the arc persists for any period of t1me,1t Wlll cause disintegration of the electrode. Moreover, the body of mercury 32, after breaking the thread 33 and disconnecting itself com.- pletely from'the electrode 31, may not possess suflicient momentum to insure that at all times the mercury body will flow rapidly away from the electrode 31.

Referring to Fig. 5, the electrode 34 is shown as being provided with a core 35, similar to the electrode shownin Fig. 2. As the body of mercury 36 flows away from said elect-rode, a substantial portion of mercury, indicated at 37 will adhere tenaciously to the bottom of the core 35. The mercury will be stretched as indicated at 38 to a narrow crosssectional area at a substantial distance from the electrode 34. The force of adherence between the core 35 and the body of mercury 37 is sufiicient to cause the body of mercury 36, on receding further .from the electrode 34, to break at the narrow cross-section portion 38. The meniscus of mercury 36 will then flow rapidly away from the electrode 34 after said rupture occurs. In this manner the arc occurs between two bodies of mercury and not at the surface of the electrode 62. The electrode is thus protected from disintegration meniscus with respect to theelectrode illustrated in Fig. 2 and described above would be just'as applicable to the electrode illustrated in Fig. 3, that is, a substantial portion of mercury would adhere tenaciously to the bottom of the core 25 and the body of mercury in receding from the electrode-24 would break at a substantial distance from said electrode,

thereby arcing between two bodies of mercury and not at the surface of the electrode 24.

The body of mercury 19 in the container 10 which serves to bridge the electrodes 11 and 12 may be chemically pure, in fact in many circumstances this is desirable. However, in order to increase the mobility of the mercury to efiect a rapid flow back and forth in the container, a small quantity of a solution of hydrocyanic acid, or other compounds of cyanide, may be mixed with the mercury. This process of treating mercury renders the same highly mobile, without affecting its electrical conducting properties or causing its deterioration or disintegration when embodied in a contactor, and is equally as desirable under other and different circumstances.

As has been hereinbefore stated, it is pref erable to have the electrodesll and 12 of different construction, the electrode 12 being made of any suitable material, preferably an iron chromium alloy or iron alone, while, the

electrode 11 comprises a main body portion which may also be made of iron or an iron chromium alloy, said body portion having a core of Monel metal; Since the monel core of the electrode 11 readily amalgamates or wets with mercury, on tilting the contactor, the body of mercury 19 will adhere to said electrode 11' until the proper angular displacement of the contactor is effected whereafter the body of mercury will snap away from the electrode 11. As'the electrode 12 is of such material that it substantially precludes mercury therefrom, the body of mercury 19 is :not obstructed in its rapid flow to andaway from the electrode 11.

From the foregoing, the advantages resid ing in the electrodes will be apparent since a substantial film of mercury will adhere to either of the electrodes illustrated in Figs. 2

. and 3 by reasonof the monel core portions and subsequent-breaks of the arc, whereby the breaks will occur between two mercury bodies, namely, the body of mercury'adhering to the electrode and the main body of mercury 19. Electrodes constructed in accordance with those shown in Figs. 2 and 3, and in the manner hereinbefore described, are substantially non-disintegrating and non-deteriorating since, as pointed out, the electric breaks and makes occur between two mercury bodies which are highly satisfactory electrical contact maln'ngmediums.

The material monel is well known in the art and its composition is also well known in the art. For further information asto this material and its physical properties, reference may be had to pages 1935 and 1936 of the publication entitled Handbook for Electrical Engineers by Harold Pender, editorin-chief, and published by John Wiley & Sons, Inc., and copyrighted in 1914, as well as to pages 531 and 532, inclusive of a publication entitled Kents Mechanical Engineers Handbook, 10th edition, 1925,'publishedby John Wiley.& Sons, Inc. That monel is a well known material appears from the advertisement on page 91 of the October 20, 1928 issue of the publication entitled The Literary Digest While but two specific embodiments of this invention have been shown and described, it is to be understood that the invention is not to be limited to these specific disclosures since various modifications will be apparent to those skilled in the art without departing from the spirit and scope of this invention,'

and, therefore, this invention is to be limited only by the appended claims and the prior art.

I claim:

1. A contactor com rising spaced cooperating electrodes one 0 which is substantially non-amalgamating with mercury and the other of which is made of monel.

2. A contactor comprisin cooperating spaced electrodes one of whic is made of a of a material substantially non-amalgamat- I ing with said mercury.

4,. A contactor comprising anfelongated hermetically sealed container, cooperating electrodes spaced longitudinally of the con tainer, and a movable meniscus of mercury contained therein, the electrode immediately adjacent to the end of said container being of Monelcmetal to which a mercury film readily adheres, and the other electrode being made of a chromium iron alloy.

In witness whereof, I have hereunto subscribedmy name.

LOUIS A. M. PHELAN.

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