US1696571A - Electric switch - Google Patents

Description

Dec. 2 5, 1928.

J. D. HILLIARD 'ELECTRIC SWITCH Filed Jan. 6, 1923 Patented Dec. 25, 1928.

UNITED STATES 1,696,571 PATENT OFFICE.

.TOmQ' D. HELLARD, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 ELECTRIC COMPANY, A CORPORATION 0F NEW YORK;

ELECTRIC SWITCH.

Application led January 6, 1923. Serial No. 611,153.

My invention relates to electric switches and especially to switches of the ltype adapted to interrupt a circuit by the separation of-contacts immersed in an insulating or arc-extinguishing fluid.

When an electric arc is formed by the separation of switch contacts within an arcextinguishing fluid, such as oil, a part of the fluid ambient the arc path is subjected to a high temperature at which it is suddenly vaporized and dissociated to form incandescent or highly heated vapors and gases. This sudden eneration of vapor and gases produces witin the fluid body pressures which arerapidly propagated through the Huid massto the tank walls and which may be of suiicient intensity to seriously stress or distort the switch tank. -These gases may throw oil-into the openings or vents provided in the tank cover for the purpose of ventilation, thereby clogging ythe openings and preventing the free-escape of the gases.

The interrupting capacity ofa well designed -fiuid break switchL is largely determmedby the pressure which its tank will withstand. The pressure to which the tank is subjected is dependent upon the volume.

of gas generated by an arc between the switch contacts. vThe disposition of the gas, therefore, becomes a`consideration of paramount importance, and any means designed to facilitate the disposal of the gas materially increases the interrupting capacity of a given switch structure.

At 150 pounds per square inch oil issues from a vent at a velocity of about 175 feet per second whereas the switch gas is discharged at. about 6,000 feet per second under the same conditions. For this reason it is highly desirable that the gas be segregated from the oil before it reaches the point of egress from the switch tank. In accordance with my invention means are provided. for removing the gas from the immediate vicinity of the oint at which ,it is created. In this way t e pressure produced by the generation of a given volumeof gas 1s materially reduced and the interrupting capacit of a given switch structure is correspon ingly increased.

one embodiment of my invention I provide within the tank above the surface of the liquid a battle through which extend discharge pipes leading from a oint near the arc to a separating chamber, ormed between the cover of the switch tank and the bale, where the gas is separated from-the vapor and liquid which are cooled and returned to the main liquid body while the gas is discharged through suitable vents in the tank cover. In another illustrated embodiment of my invention the mixture of gasand liquid is removed from a point near the arc to a separating chamber or separator placed outside the switch tank for the purpose of separating the gas from the liquid and returning the liquid to the tank. B the term separating chamber, as hereina ter used, I mean to include any sort of chamber provided for the purpose of separating the gas from the liquid whether the same be placed inside or outside the switch tank. My invention may be embodied in other forms than those shown and described.

The modifications shown in this application are shown in Figures 4 and 5 of my copending application, Serial No. 611,152 filed Jan. 6, 1923 in which are broadly claimed means for removin the gases directly from the place of their ormation to a point outside the liquid body.

An object of my invention, therefore, is to provide means for lessening the danger of injury to the switch tank by pressure created upon the sudden generation of gas at an arc between the switch contacts.

A further object of my invention is to' provide means to facilitate the discharge of the as from the switch tank for the purpose o increasing the interrupting capacity of the switch.

Other objects and advantages will appear as my invention is considered in detail.

My invention will be better understood from the following description taken in connection with the accompanying drawings and its scope will be pointed out in the appended claims. Y Q

Referring now to the drawing, there 1s shown in Fig. 1 a sectional view of a switch in which one form of my invention has been embodied, and in Fig. 2 a similarview in which my invention is shown in a slightly different form.

Fig. 1 shows a switch tank 1 adapted to contain an insulating fluid 2 and provided with an insulating lining 3. Upon the tank 1 is a cover 4 provided with gas vents 5 and suitable openings Athrough which are .ducting pipe 18 and pipe 19 made oi insu-v -lating material arranged to conduct the supported the insulators 6, clamping rings 7 and bolts 8 being provided for the purpose of holding the insulators in fixed re lation with the tankccover. Suspended from the cover 4by vmeans of supports 9 and bolts 10 is a baille 11 so constructed as to assure that the pressure between the oil level 2 and baie 11 is greater than between baffle-11 and tank cover 4'when the switch interrupts the circuit and also arranged .to prevent the throwing of a large mass of oil into the vents 5. when the breaker operates. The chief function of the baille 11 is to force the gas 'generated by the ` arc throu'g'h tube 18 and 19 practically unmixed with oil and into a. corresponding high velocity of. escape. Extending through a stuing box l2 in the cover 4 is the operating rod 13 attached to the .-bridging member 14 and movable to make and break contact between this member and fixed main and auxiliary contacts 15 and A16 respectively which are in electrical connection with the switch terminals v17 and are supported by the insulators 6. Also.

supported by the insulators 6 are the congases formed at an arc between the auxiliary contacts 16 and the bridging member 14 away from the place of their formation to a point above the bale 11.

The modification of Fig. 2 dilfers from that of Fig. l onlyin that the gases formed at an a'rc between the switch terminals are discharged through a pipe 2O connected to the hollow switch lead 21 which is arranged to conduct the gases and any oil and oil vapor that may be mixed therewith to a separating chamber 22. Suspended from the top of the separating chamber 22 by bolts 23 are balles 24 and 25 provided for the purpose of cooling and condensing the oil and lvapor mixed with the gas and preventing their discharge through the opening 26 in the terminal of theswitch. Gravel masses 27 and 28 supported upon the partition 29 and the bottom 30 of the separating chamber 22 are provided for the purpose of retaining the oil for return to the tank 1 through the openings 31 provided for ,that purpose.

In the operation ofthe switch shown in Fig.- 1 from the illustrated closed position, the operating rod 13 is moved to break contact between the bridging -member 14 andthe main fixed contacts 15. Upon further movement of the operating rod 13 Vthe circuitis interrupted by the separation of the arcing members 14 and 16 and any arc formed between' these members will volatilize ordissociate some of the liquid ambient its path.

As the distance between the switch contacts Y is increased, the magnetic field produced by the current to be interrupted will force the arc to the lower edgeof the pipe 18 from which position the gas is readily discharged through the pipe 418. Due to the pressure 'existing within the tank, the gas-is forced upwardly lthrough the pipes 18 and 19 to a point above the bale 11 where the liquid and vapor are cooled and from whence they are returned to the main liquid body while the gas escapes through the vents 5. The operation of the switch shown in Fig. 2 differs from that just described in that the gas is separated from the oil and oil vapor in the separating chamber 22 instead of in the chamber formed between the tank cover 4 and the bale 11. l

The removal of the gas directly from the point at which it is generated is of particular advantage in that comparatively little liquid is mixed with the gas which is dis- 'charged from the mass f liquid, and the danger of oil reaching the lVents 5 and preventing free escape of the gas is thus greatly reduced. Y

My invention may be embodied in otherl forms than that shown and described and I,

therefore, intend to cover by the appendedA claims ald changes and modifications appari entto those skilledin .the art and within the scope of my invention.

What I claim as new and kdesire .to secure by Letters Patent of the United States, is

1. An electric switch comprising a closed tank containing an insulating' liquid the i level of which is-spaced below the top of the tank, switch contacts adapted to be separated beneath the surface of said liquid, a batHe arranged aboveV the level ofthe liquid and spaced below the top of the tank, a separating chamber arranged above the tank, and means for conducting gas and liquid 'from the vicinity of the contacts through the bale and space above the liquid to the separating chamber. i

2. An electric switch of the type wherein a circuit is'broken by means of contacts arranged upon their separation to extinguish any arc formed between 'them byxdrawing the same in an arc-,extinguishingliquid apt to he volatilized and dissociated at the arc temperature into permanent gases which produce pressure within said liquid comprislng a lbafle above said contacts, a separating chamben above said bale, and a hollow lead Y A.JOHN D. HILLIARD.

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