US1595936A - Electric switch - Google Patents

Description

Aug. 10 1926.

J. D. HILLIARD ELECTRIC SWITCH 11 IIIIIVI Original Filed Feb. 8. 1921 Irv/ermor- JOhnDHiHiar'd His Annorfne.

Patented Aug. l0, 1926.

UNITED STATESv PATENT oFFICE.

JOHN D. HILLIARD, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK.

ELECTRIC swITH.

Original' application led February 8, 1921, Serial No. 443,440. Divided` and this November 23, 1922. Serial No. 602,702.

My invention relates to electric switches, and especially to switches of the type wherein a clrcuit 1s broken by the separation of contacts immersed in an insulating or arcextinguishing fluid.

When opening high power .circuits under oil, the arc formed upon separation of the switch contacts causes a certain amount of the oil to be disassociated or volatilized,

thereby producin within thtJ body of the oil a quantity o highly heated gas,l the generation of which may create a pressure suilicient to eject oil from the tank or even to injure the tank itself. The oil ejected from the tank is in a more or less atomized condition and is often carbonized so that it forms a black .deposit on objects with whichit comes into contact.

The koil is ejected by highly lheated ygas which, upon contact with the air, may cause secondary explosions of sulicient violence to burst the oil tank or tear it from its supports. Even where the direct injury from the Vexplosion is slight, the fire risk is increased, and it has frequently happened that such explosions. have resulted in a short circuit which seriously interfered with the operation of the system to which the switch was connected. f

According to the invention disclosed in my Patent 1,537,353, May 12, 1925, of which` this application is a division, and which is assigned to the same assignee as the present application, I so construct the switch that when the circuit is broken within an insulating -fluid, such as oil, no insulating fluid is ejected from the tank and secondary explosions caused by Icontact vof heated gas with the air are prevented. This end is accomplished by interposing in the path of the fluid Set in motion by the arc, a means which will preventthe ejection of liquid from the tank, will separate `a large part of the oil vapor and atomized oil from the gas, and will cool the fluids ejected from the tank tog. a temperature below that at which'they spontaneously ignite uponcontact with the air. These results are produced by causing the .moving vfluid to be broken vup into a plurality of fine streams which are caused to flow by circuitous passages through a cooling material.- While the specific means usedsto break `Aup the moving fluids into aplurality of tine application led streams may assume a variety of .form-s, I prefer to use a material which has a high dielectric strength such as quartz gravel,`

which may vary considerably in size,

ebbles from 1/2 to 1%, p

inch being satisfactory in many cases.

Since the quantity of hot vapor and gases generated within the body of insulating luid upon the interruption of a high'power circuit depends upon the time during which an arc persists between4 the switch eleotrodes, it is desirable to reduce, in so far as is possible, the time during whichthis arc high power circuit may be quickly and ef-y fectively interrupted. r

My invention will/be better understood from the following description taken in connection with the accom anying drawing and its scope will be pointed) out in the appended claim Referring now to the drawing, there is shown in the single figure thereof a metallic casing 1 closed at the top by meansl of a cover 2 having small outlet passages 3. This casing forms one terminal of the switch and is provided with a stationary contact '4 adapted to cooperate with a movable contact 5. Suspended from the cover 2 by means of insulator 6 and a metal tube 7 is a metallic casing 8 lined on the inside and covered on the outside with insulation 24, and having an insulator 9 supported 'through an opening in its bottom. The insulator 9 is rovided with a central opening through which the movable electrode 5 may bemoved to open and close the circuit. A small bleed hole 10 serves to allow the insulating fluid 1l to assume its natural level in the casing 8. Extending lengthwise the casing 1 are wooden rods 12 which are provided with shoulders. 13 upon which is supported a perforated ring 14 of insulating material. Between this ring and a similar ring 15 is interposed a mass of gravel or other suitable fragmentary material designed to cool and condense' the gases and vapor created within the insulating fluidl 11 by an arc formed between the electrodes 4 and 5 uponI their separation under load.

The baiiles 17 and 18 are provided be.- tween the outlets 3 andthe gravel batlie 16 to form a tortuous passage by means of which the gases are further cooled before they escape from the casing 1. Surrounding the movable electrode in the lower part of the casing 1 is a battle 19 which together with the bottom of this casing forms the pressure chamber 21 Within which the electrodes fl and 5 are separated to open the circuit. rlhe baffles 17, 18 and 19 are supported by insulating tubes 20 which surround the rods 12.

The operation of my invent-ion is as follows z-Upon separation of contacts l and 5 under load there is produced an arc which' volatilizes or disassociates some of the insulating fluid ambient its path thereby creating pressure within the chamber 21. As the movable electrode 5 is withdrawn from this chamber it is followed by a -blast of insulating fluid which tends to cool and extinguish the arc. Upon further movement of the electrode 5, the arc is drawn through the insulator 9 into the pressure chamber 22 formed by the casing 8 and there is thereby created within this chamber a pressure which forces a blast ofl insulating fluid out of it through the opening in the insu- Y lator 9 into the discharge chamber 23 formed between the casings 8 and 1. These two blasts of insulating fluid are discharged in opposite direction-s into the path of the arc -which is effectively cooled `and extinguished thereby. l

My invention may be embodied in other forms than that shownand described, and I therefore intend to cover by the appended claims all changes'and modications apparent to those skilled in the art and within the scope of my invention.

What I claim as new and 'desire to secure by Letters Patent of the United States i., z-T

1. A fluid switch comprising two pressure chambers arranged to discharge in opposite directions, and a dischargechamber interconnecting said pressure chambers.

2. A iiuid switch comprising a plurality of pressure chambers having restricted dis' charge openings and arranged to discharge in different directions, a discharge chamber having an outlet and interconnecting said pressure chambers, and a perforated barrier interposed between the discharge openings of said pressure chambers and the outlet of said discharge chamber.

3. A fluid switch comprising two pressure chambers arranged to. discharge in opposite directions, a discharge chamber interconnecting said pressure chambers and having an outlet, and a barrier interposed between the discharge openings of said pressure chambers and said outlet, said barrier comprising granular material.

4. A switch comprising a pair of pressure chambers having restricted discharge openings and containing an insulating fluid, two

-electrodes arranged to form an arc in each of said chambers whereby pressure is created therein, and a discharge chamber for receiving the iiuid expelled from said pressure chambers by the pressure so created.

5. A switchv comprising a plurality of pressure chambers containing a fluid andA having restricted discharge openings arranged to discharge said fluid in different directions, electrodesarranged to produce an arc in said chambers whereby pressure is created therein, and a discharge chamber for ,receiving the fluid expelled from said pressure chambers by the pressure so created.

6. A switch comprising a plurality off pressure chambers containing a duid and having restricted discharge openings arranged to discharge said fluid in different directions in sequence, electrodes arranged to produce an arc successively in said chambers wherebypressure is created therein, and a discharge chamber for receiving the liuid pressure socreated.

7. A switch comprising a plurality of pressure chambers containing a fluid and having restricted discharge openings, electrod'es arranged to produce an arc whereby pressure is created in said chambers, said chambers being arranged to discharge said fluid into the path of said arc in opposite directions in sequence, and a 'discharge chamber for receiving the fluid expelled from said presure chambers bythe pressure so cre-l ate 8. A fluid switch provided with two pressure chambers and a discharge chamber between the same, said chambers being adapted to contain an insulating fluid and -electrodes arranged to produce an arc at each of said chambers, said' pressure chambers being provided with restricted openings communicating with said discharge chamber whereby upon the formation of said arcthe insulating duid in each of said pressure chambers will be discharged into the path of the arc in said discharge chamber.

9. A fluid switch provided withtwo pressure chambers anda discharge chamber between the same, said chambers being adapted to contain an insulating fluid, electrodes arranged to produce an arc at' each of said chambers, said pressure chambers being provided with restricted openings communicat- -expelled from said pressure chambers by the iio unon the formation of said arc an insulating fluid in each of said pressure chambers Will discharge chamber,

be discharged into the path of the are in said being providedjvith an outlet and granular cooling means Within said discharge chamber between said openings and said outlet.

10. A fluid break switch comprising a conductive casing adapted to contain an insulating Huid and having a cover provided with openings for the escape of gasfrom said easing, means forming a pressure 'chamber near the top of said casing support-ed by and insulated from said cover, rods extending betwveen the ends of said casing and having shoulders near the top of said easing, a series of offset bailles supported upon said said discharge chamber shoulders and spaced apartl by insulating sleeves surrounding said rods, one of said baffles being formed of gravel held between perforated insulating members, additional insulating sleeves surrounding said rods, an insulating member held in position by said sleeves and forming a second pressure chamber in the bottom of said casing, a stationary electrode Within said second pressure chamber in conductive relation with said casing, and an electrode movable through Said pressure chambers'to make and break Contact with' said stationary electrode.

In Witness whereof, IA have hereunto set my hand this 22nd day of November, 1922.

JOHN D. HILLIARD.

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