US1512735A - Electric switch - Google Patents

Description

Oct. 21 1924. 1,512,735

C. E. BENNETT ET AL ELECTRIC SWITCH Original Filed Sent. 9. 1919 3 Sheets-Sheet 1 [NVLNTORS CHflRLEs L. BENNETT C'HRRLES G. fins/T 3 K/p ATTORNEYS Oct. 21 1924. I 1,512,735

C. E. BENNETT ET AL.

ELECTRIC SWITCH Original Filed Sent. 9. 1919 a sheets-Sheet 2 5 Eg E 9- f a? r T; T 6 M J r/a.a 4

INVENTOM' (amass fixcmverr 'C'HHRLE q. fins/r A IITORNEYJ Oct. 21 1924.

C. E. BENNETT ET AL ELECTRIC SWlTCH Original Filed Sent. 9, 1919 3 SheetsSheet FIG. 6

FIG-J INVENTORS C'HHRLES EBE/YMEv-T CHHFR'LES Q1/7351? 3 Km m ATTORNEYS Patented Oct. 21, 1924.

UNITED STATES PATENT OFFICE.

CHARLES E. BENNETT AND CHAR-LES G. ADSIT, 0F ATLANTA, GEORGIA, ASSIGNORS, BY

MESNE ASSIGNMENTS, TO BALT MANUFACTURING COMPANY, OF ATLANTA, GEOR- GIA, A CORPORATION OF GEORGIA.

ELECTRIC SWITCH.

Application filed September 9, 1919, Serial No. 322,642. Renewed September 12, 1924.

To all whom it may concern:

Be it known that we, CHARLES E. BENNETT and CHARLES G. Ansir, citizens of the United States, residing at Atlanta, in the county of Fulton and State of Georgia, have invented certain new and useful Improvements in Electric Switches, of which the following is a specification.

Our invention relates to electric switches, and particularly to heavy duty switches .for installation in power lines of medium or high voltage for either direct or alternating current. The object of our invention is to provide a switch of high capacity having means for automatically cooling and quenching the are which tends to form on the opening of the switch, an energy absorbing medium too cold for the are to be maintained.

In the accompanying more or less diagrammatic drawings- Fig. 1 is a vertical section through a switch in which my invention is embodied in one form, and showing the switch in closed position;

Fig. 2 is a similar View showing the switch open;

Figs. 3 and 4 are similar views of a modilied construction; and

Figs. 5and 6 are similar views of a sec ond 'inodification.

As shown in the more or less diagrammatic embodiment of our invention illustrated, the switch comprises, in the form indicated in Figs. 1 and 2, a tank or other liquid container 6 for an electrolyte 9, of rapid and high heat absorbing capacity, such as. water, which partially fills the tank.

A, tube 5, preferably of insulating material, I

dips at itslower open end into the electrolyte, but is closed at its upper end by a plug 12 pierced by a vent 4c and by a central hole through which slides the conductor rod 3 which forms the movable member of the switch proper. An air space 10 is confined between the electrolyte inth'e tube and the plug 12 of the upper endthereof. At the lower end of the rod 3-is the terminal 11,

,here shown in the form of a conical plug adapted to enter the cooperating terminal cup 7 mounted on the bottom of the tank and submerged in theelectrolyte 9. Any suitable means may be employed to operate the rod 3. As here shown it is connected at outgoing main 8 is attached to the tank or otherwise brought into electrical connection with the terminal 7 within the tank.

When the rod 3 is lifted the terminal 11 parts from terminal 7 and an arc tends to form therebetween. As the rod moves rapidly upward the arc passes through the electrolyte n ow separating the terminals.

.This liquid performs the very important function of absorbing or cooling the heat energy of the arc, and thus tends to rapidly quench it. Should the are not be quenched instantly the heat generated by it causes the electrolyte in the tube, and also the air or, vapor in theair space 10, to expand, thus expelling the liquid from the lower end of the tube. The are is thus not only in direct contact with the liquid, which absorbs the heat thereof, but the circulation of the liquid caused by its expulsion from the tube 5 through the path of the arc, breaks the arc and opens the circuit. The vent 4 is provided to prevent excessive pressure in the tube 5, which forms an expansion chamber within the tank, the arc being drawn in this expansion chamber and through the liquid therein.

In Figs. 3 and l we have shown a modified arrangement by which a double break in series is secured. This is attained by making the tank 6 of sufficient size to acc0m1nodate two insulating tubes 5, through the head of each of which passes a conducting rod 3 connected at its upper end to an insulating bridge piece 6. The mains 1 and 8 are connected respectively tothe two rods 3, and in the closed position of the switch the circuit is completed between the fixed terminals T either through the electrolyte or through the tank, or both. The rods are lifted by the balance lever '1) connected to the insulation bridge piece 6 through the insulator 16,

I mounted in the linker In this form we have also shown the tank 6 insulated by mounting it on insulators 15 in a surrounding tank 14:,

from which it is separated by a quantity ofoil 18, or other insulating material. The

outer tank may for additional protection be.

grounded at 9. On the opening of the switch the arcs which tend to form between the switch terminals l1 and the fixed terminals 7 are quenched in prec sely the same manner as-that above described.

In Figs. 5 and 6 we have shown an ar rangement in which the position of the parts is reversed, the fixed terminals 7 being arranged in the upper portion of the expansion chamber, and the movable terminals ll adapted to be drawn down into the liquid in the lower portions orthe tubes 5 when the have found such a construction unnecessary to the efiicient operation or the switch.

The present switch is particularly effective in interrupting tenacious arcs producer. between the switch terminals in a high volt age direct or alternating current circuit.

The heat of the arc is absorbed by a medium .whichtends to cool and quench the arc.

The function of the expansion chamber is important since the expulsion of theelectrolyte from the tube causes rapid circulation of the electrolyte in the apparatus and forces the water'or other liquid into direct contact with the'arc, thereby absorbing the heat of the latter. It is impossible to maintain an are between two points oi? contact submerged in the liquid when the latter is rapidly circulated. An arc produced through a body of water or the like, when it is in static condition, forms a holein the water, the diameter of the hole, so to speak, varying with the amount of energy passing through the arc above. Upon the slightest agitation of the liquid, 'however,this hole is broken up and the path of the arc is lengthenedand cooled at. the Sametime, and the are immediately quenched. This phenomenon is utilized in the present apparatus to quench the arc in a most eflicacious mannen Of course the normal liquid level in the tube and tank is reestablished at once upon the quenching of the arc, since the vent -l permits the escape of the air and the steam generated in the expansion chamber and permits the liquid to termined'level. y r

The operation of this switch is obviously unlike in principle to that or an oil switch,

tween the terminals. rise again to its prede-' in which the interruption of the' arc is de-' pendent upon the insulating qualities of the liquid (oil) surrounding the contacts. On the contrary, the liquid or the presentine terrupter is a conductor, and the quenching of the arc is dependent solely upon its.at

tenuation in a medium which rapidly absorbsthe heat of the arc, and at the same time breaks up its normal path.

l urtherinore, when 'an electric arc formed between two contactapartial vola' tihzation of the contacts themselves occurs, forming a conductive gas which tends to provide path ot'low resistance between the contacts and thus to facilitate the maintenance of the arc. This cannot occur,'how ver, when the contacts are immersed in a liquid that has high heat absorbing qualities and that is vaporized and rapidly circu lated as a result of the formation of the arc in contact therewith. i

The particular construction and arrange ment of parts'illustrated may obviously'be variously modified without departing from what we claim as our invention. We claim 1. An electric switch comprising a liquid container, a readily vaporizing electrolyte of high heat absorbing capacity contained therein, a member at least partially submerged in said electrolyte and having an interior chamber open to said electrolyte, in combination with a movable switch memberdrawing an arc in said chamber onthe opening :of the switch.

2. An electric switch comprising aliquid container, a readily vaporizing electrolyte of high heat absorbing capacity contained therein, an insulating member at least par tially submerged in said electrolyte and having'an interior chamber open t'oisaid electrolyte, in combination with a movable switch member drawing an'arcinsaid chamber on the opening of the switch.

3. An electric switch comprising a liquid container, a readilyvaporizing electrolyte of high heat absorbing capacity contained Y therein, a member at least partially submerged in said electrolyte and having'an interior chamber open to 'saidelectrolyte, but vented to prevent excessive pressure therein, in combination with a movable switch member drawing an arc in said cham her on the opening of the switch,

wine electric switch comprising a pair of switch f terminals, and means'for maintaining in the space be'tween, said terminals,

inthe open position-of the switch, aci'rculating conductive and readilyvaporizable liquid adapted to quench an are formed be- 5. An electric switch comprising a pair of switch terminals, and means for main taing in, the space between the terminals, in

the open position of the switch, a conductive Z by the heat of an are formed between said terminals.

7. An electric switch comprisingrelatively movable contacts and an associated conductive and readily vaporizable electrolyte in which at least one of said contacts is immersed on the opening of the switch, together with means for insuring the rapid circulation of the electrolyte in the vicinity of the arc during the maintenance of the latter.

8. An electric switch comprising relatively movable contacts and an associated conductive and readily vaporizable electrolyte in which at least one of said contacts is immersed on the opening of the switch, said electrolyte having the capacity to rapidly absorb the heat of the arc and thus to chill its path between tne contacts, together with means for insuring the rapid circulation of the electrolyte in the vicinity of the arc during the maintenance of the latter.

9. The method of breaking an electric circuit which comprises separating a pair of contacts beneath the surface of a readily vaporizing and heat absorbing electrolyte, trapping the vapor generated by the head of the current flow in the electrolyte above the surface of the electrolyte, and causing the electrolyte to move downward and away from one of the contacts under the pressure of said trapped vapor.

10. An electric switch comprising a liquid container, a readily vaporizing electrolyte of high heat absorbing capacity contained therein, an insulating member at least partially submerged in said electrolyte and atfording a pressure chamber open at its lower portion to the electrolyte and substantially closed at its upper portion, in combination with a pair of cooperating relatively movable switch contacts, and means for separating said contacts to open the switch one of said contacts in the open position of the switch being located in said chamber, whereby in the open position of the switch current is caused to flow through the electrolyte in said closed chamber and at least partially vaporize said electrolyte, the vapor so generate-cl being trapped in the upper portion of the chamber and serving to depress the electrolyte and thus cause the same to move away from the switch contact in said chamber.

In testimony whereof we have signed our names to thi specification.

CHAS. Gr. ADSIT. CHARLES E. BENNETT.

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