US2640897A - Liquid break circuit breaker - Google Patents

Description

June 2, 1953 w. E. PAUL.

LIQUID BREAK CIRCUIT BREAKER Filed Jan. 5, 1951 5 l I IWI :nl

Patented June 2, 1953 UNITED STATES LPT-ENT OFFICE William E. Paul, Schenectady, N. Y., assignor to yGeneral `Electric Company, a corporation #of rNew York ApplicationJanuary 3, 1951, Serial No. 204,178

7 Claims. 1

This invention relates to liquid break circuit 'breakers of the so-called impulse type, ii. e. breakers in which a positive now of insulating liquid is supplied between the contacts of the breaker during separating movement thereof `for thepurpose of extinguishing the arc drawn therebetween.

In'this type of breaker, impulse action is ordinarily provided by means .of a spring actuated piston which is movable during the openingmovement of 'the contacts to supply a 'blast of arc extinguishing 'uidto the are. Pressure produced by the are tends to impede the operating movement of the impulse .piston and if the current to 'be interrupted is sufliciently large this pressure may even reverse the piston thereby ,preventing effective arc extinguis'hment.

In Patent 2.1022768-Trencham granted December 21, 1937, and assigned to the assignee of this invention, an arrangement .is disclosed wherein provision is made for .reducing or relieving the pressure set up ,at the contacts .due `to the 'interruption of heavy currents. 'In this Trencham et al. patent the pressure relieving means eiiectively relieves atleast to someextent the 4pressure which tends to interfere with the piston movement but due to the action .of the pressure relieving means vthe flow of arc .extin-v guishing fluid toward .the arc is not as .positive and direct Aas might be required for all conditions to be encountered.

Aprincipal object of this invention is .to provide animproved.impulsepiston arrangement for circuit breakers wherein suitable passagewaysafford direct communication vbetween the region in which vthe arc is formedand-each side of the piston for the purpose of controlling the .back thrust exerted on the piston due to arc pressure.

Another object of the invention is the provision of an improved circuit breaker of .the impulse type wherein positive Yiiow of iluid .for .arc extinguishing purposes isachieved Without allowing `arc pressure to impede .the working :movement of the impulse producing piston.

Still .another object of the invention is to `provide an -improved impulse .type circuit breaker wherein the operating movement of .the impulse piston is substantially independent ofthe .magnitude oi .the current to be interrupted.

According to the invention a piston for an impulse breaker is arranged with respect .to the interrupting contacts in such a .wayythat pressure dueto the arc drawn at the contacts is eiectively ktransmitted to both the working 'face of' the piston and to the opposite face thereof. In

2 this way pressure developed .due to the arc is prevented 'from interferring with the Working movement of thevpiston.

'Iheinvention will be more fully understood from the following description takenin conjunction with the accompanying drawings and the features Aof novelty which characterize the invention will be pointed out with particularityin the claims annexed to and forming va part of this specification.

In the drawing'Fig. l represents a side sectional view Aof a circuitinterrupter embodying the inventiorhFig. 2 'is a side .sectional view at right angles .to Fig. 1,"Fig. Bis a cross sectional View of the arrangement shown in `Figs. l and 2 taken along the line '3 3 of Fig. l, and Fig. 4 is a detail view oi' a portion of vthe lpiston structure comprising the invention.

.The interrupter unit as shownin thedrawings is adapted for .use in tank ltype circuit breakers which, Vas is Well known, are provided with a pair of interrupting units immersed in oil .contained in an enclosing ytank together with a vertically movable transversely disposed bridging bar which moveslintoandout oengagement with each .interrupting unit. Such a pair of series interrupters disposed in acommoncircuit breaker tank is depicted .in U. S. Patent 2,513,918 to Coggeshall which is assigned to the assignee of this invention. It will'be understood, however,

that .the invention is .also applicable to other i types of circuit breakers .as well. For example, ,the principles embodied inthe invention are applicable to the so-called oil poor circuit breakers d. Adapter member 'l is provided with adown-v Wardly vextending conducting portion S which maybe integrally formed with the top vplate of theinterrupter unit. Enclosingcasing [theonstructed of strong pressure-resistant ,insulating material, is secured to the top plate@ by means of bolts il, and bottom ^plate l2 of the interrupter unit is securedto :theenclosing structure or casing l0 by means of'bolts I3. Secured to, 55

or formed integrally with, the top plate 9 is a iixed contact I4 having a contacting surface I5. Movable contact I5 having a contacting surface iiia for abutting engagement with I5 is provided with downwardly extending segmental members or nnger type contacts I'| which slidingly telescope with the hollow upstanding contact portion i8 shown formed integrally with the conducting bottom plate I2. The spring-driven impulse piston or nuid moving baiiie I9 is adapted to carry the movable contact IS and is provided with an indirect iiow passageway therethrough comprising a vertical inlet passage and a vertical outlet passage 2| interconnected at their inner ends by a cross-blast channel. Further'- more, the piston i9 is provided with a horizontal vent passage 22 the outer ends of which are arranged in registry with the elongated venting apertures 23 disposed on either side of the casing I0. Thus downward movement of piston I9 and of movable contact I6 will result in a flow of fluid from the space below the piston upwardly through vertical inlet passage 20 across the space occupied by the arc drawn between contacts I4 and IB and upwardly through vertical outlet passage 2| into the region in the casing I0 above the piston IB. It will be observed that pressure eveloped in the region of the arc, after the contacts are separated, can be vented directly to the space outside the interrupting unit through the horizontal relief vent passage 22 and the registering apertures 23. The apertures 23 are made suciently long to accommodate the venting operation even though the piston I9 and contact I6 are in their lowermost position or engagement with the bottom plate I2. It will also be observed that whatever portion of the pressure caused by the arc which may not be quickly vented through the vent passage 22 and apertures 23 is transmitted substantially equally through the vertical passages 20 and 2| respectively to the space below the piston and to the space above the piston. The pressure caused by the arc and which is not relieved through vent passage 22 is ineiiective to impede working movement of piston I9. Stated otherwise, the structure comprising the casing IIl, the top plate 9 and the bottom plate I2 ordinarily would be substantially fluid tight except for the vents 23 and, by virtue of the passages 23 and 2| which afford a direct, closed means of communication between the arc and each side of the piston, any unrelieved pressure due to the arc which might otherwise tend to impedo the working movement of the piston is therefore effectively counterbalanced. This does not necessarily mean that it would be desirable in every application or the invention to cause equal and opposite forces due to arc pressure to be exerted on the piston. It is conceivable that one force should be greater than the other for certain applications of the invention. To this end one of the passages such as 20 or 2| could be made larger than or otherwise dissimilar from, the other passage, or the effective piston areas could be made different, so that a predetermined differential action would be obtained.

For the purpose of compensating adverse forces affecting the piston I9, projecting guide rods 24, which are shown formed integrally with the piston, move reciprocatingly therewith through openings provided in top plate 9. These rods oonstitute means whereby the volumetric capacity of the casing I9 is maintained constant as the piston I9 is moved downwardly by the pull of its operating and guide rods 25 which are reciprocable through openings provided in the casing bottom u CIK .4 plate I2. The compensating rods 24 and operating rods 25 and their respective openings in plates 9 and I2 preferably should form substantially fluid tight seals, and it will be readily understood that as portions oi the operating rods 25 move out from the casing I0, the volume thereof is not diminished by reason of the corresponding entry of the compensating rods 24 which are of like diameter.

For actuating the piston, the rods 25 are iastened into the respective ends cf yoke member 25 which is provided with a central cylindrical recess 21 into the bottom of which the spring guide 28 is secured. Disposed about the guide 28 is a biasing spring 29 which engages the yoke 26 at the lower` end of the spring and which engages the inner upper end of the upstanding hollow contact portion i8 of bottom plate I2. Thus it will be seen that spring 29, being a compressional spring, exerts a downward i'orce on the yoke 26 thus biasing the piston I9 and movable Contact I6 to the open position at all times.

Yoke member 25 and the above-described parts associated therewith are driven to, and maintained in, the closed position of the breaker indicated in the drawings through the agency of a striker block 3|! secured, as by riveting, between the spaced ends of the paired conducting members 3| which constitute the circuit breaker reciprocable blade which bridges a pair of interrupting units of which but one is shown. Conducting blades 3I engage fixed contact ngers 32 when the breaker is closed, and it will be understood that, in the open position and after the arcs drawn between contacts I4, I6 have been extinguished, the blades 3| are widely separated from the fingers 32 for establishing an isolating gap therebetween. Yieldable means in the form of spring 3 and member 34 are interposed between yoke 26 and block 30.

The circuit through the interrupter comprises conductor stud 3, flanged plate II, adapter structures 1 and 8, top plate 9, fixed contact I4, movable Contact I6, ringer contacts I1, projection I8, bottom plate I2, fingers 32, and along the blade conductors 3|. A companion series interrupter of similar construction would of course cooperate with the left hand end of blade conductors 3| as viewed in Fig. 1.

In View of the description above, it will be understood that the breaker would be opened by initiating downward movement of the recipcocable blade contact 3l. Such movement would permit biasing spring 29 to exert a downward force on yoke 26 which in turn would exert a downward force through rods 25 on the impulse piston I 9 and arcng contact I6, Thus oil or other suitable insulating fluid would be forced from Ithe space below the piston I9 upwardly through vertical passage 20, across the region of the arc drawn between the interrupting contacts I4 and I6, then upwardly through vertical passage 2| to occupy the space above the piston I9. Excess pressure caused by a high current arc would be relieved directly and laterally through the vent passage 22 and the vent ports 23 into the enclosing oil tank. Pressure which might fail to be relieved through this means would be exerted substantially equally both above and below the piston I9 so that, to a substantial degree any stalling action of the piston I9 and parts associated therewith lfrom pressure unbalance is minimized. Furthermore, it will be observed that this uniform action of the piston I9 and of the parts associated therewith is achieved without interfering with the positive flow @of duid from the .space below the piston |19 into the region occupied bythe arc `since pressure cannot escape at any point along this closed passage.`

While the arrangementr shown in the drawing and described thus far 'utilizes a fixed contact such as I 4 and a movable Contact such vas I6, it will lbe understood that Yboth contacts -could loe arranged to move by any suitable known `arrangement. If -both the contacts were `moved simultaneously `the time of interruption would be reduced.

In order to facilitate closing of the contacts, vertical passages best shown in Eig.. y3 fare provided with check valves l355 shownin Fig. 4

for the purpose yof allowing the-oilr to lflow downwardly through passages as the breakerl is closed. Of course the valves 36 would iclosedue tothe action of their springs Sli-when the vpiston I9 is moving downwardly during an opening-foperation so as to force the oil to flow upwardly through inlet passage 20 and outlet passage 2l.

While a particular embodiment of the invention only has been illustrated and described in detail, modifications thereof will occur to those skilled in the art. It is to be understood, therefore, that the invention is not to be limited to the particular arrangement disclosed and it is intended in the appended claims to cover all modifications which fall within the true spirit and scope of the invention.

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

l. An electric circuit breaker comprising casing structure containing insulating fluid, a pair of relatively movable contacts separable within said casing, means including a piston disposed.

within said casing and movable from a normal position to an operated position to subject the arc drawn between said contacts upon separation thereof to a ilow of said fluid, said casing being substantially pressure tight in the regions thereof adjacent opposite surfaces of said piston, venting means in said casing adjacent the region in which the arc is drawn for relieving the pressure developed due to the arc, and means deilning a substantially closed passageway for affording communication between the region in which the arc is drawn and said opposite surfaces of said piston so that pressure due to the arc is transmitted substantially simultaneously to said opposite surfaces.

2. An electric circuit breaker comprising casing structure substantially filled with insulating fluid, a pair of relatively movable contacts separable within said casing, means including a piston disposed within said casing and movable from a normal position to an operated position to subject the arc drawn between said contacts upon separation thereof to a flow of said fluid, said casing being substantially fluid tight in the regions thereof adjacent opposite surfaces of said piston, venting means in said casing adjacent the region in which the arc is ydrawn for relieving the pressure due to the arc, and means dening a substantially closed passage for affording communication between the region in which the arc is drawn and said opposite surfaces of said piston, said venting means being disposed with respect to said passage so that said opposite surfaces of said piston are substantially equally accessible to the pressure developed due to the arc drawn between said contacts so that pressure due to the arc is transmitted substantially simultaneously to said opposite surfaces.

3. An electric circuit breaker comprising cas'- ving structure containing insulating fluid, ya fixed ycontact and a movable contact disposed Vywithin said casing, .means Vincluding La .piston disposed within .said casing .and movable 'with said movl'able contact from .a 4normal position to Aan ioperated position to subject the arc drawn between `saidcontacts :upon 'separation thereof '.to Aa flow Jof saidfluid, venting r.means in :said casing adjacent the region in whichjthe arc 'is drawn lfor relieving lthe pressure fdue tothe arc, vand means deilning a :substantially closed passage for affording communication between the region in which the are is drawn and V.the opposite sur- Afaces of fsaid piston "so 'that pressure due tothe are is transmitted substantially simultaneously .to said opposite surfaces, 'said venting means being disposed withairespect tto said passage so that said opposite ysurfaces -of said :piston are substantially 4equally accessible vto the pressure due to the arc drawn between said contacts.

4. An electric circuit breaker comprising casing structure containing insulating fluid, baille structure disposed in said casing and movable therein from a normal position to an operated position, a passage in said baille structure arranged so that fluid in said casing is caused to flow through said passage in response to movement of said baille structure within said casing structure, and a pair of relatively movable contacts disposed with respect to said passage so that the arc drawn therebetween upon separation thereof is subjected to the flow of said fluid through said passage, said casing being substantially closed in the regions thereof adjacent the extremities of said passage and said passage being so proportioned that substantially equal instantaneous pressures due to the arc are transmitted through said passage to opposite surfaces of said baille means.

5. An electric circuit breaker comprising casing structure containing insulating iluid, baille structure disposed in said casing and movable therein from a normal position to an operated position, a passage in said baille structure arranged so that the fluid in said casing is caused to flow through said passage in response to movement of said baille structure within said casing structure, a pair of relatively movable contacts disposed with respect to said passage so that the are drawn therebetween upon separation thereof is subjected to the flow of said fluid through said passage, venting means in said casing adjacent the region in which the arc is drawn for relieving the pressure developed within said baille structure by the arc, said casing being otherwise closed so that substantially equal pressures due to the arc are transmitted through said passage to opposite surfaces of said baille means.

6. An electric circuit breaker comprising casing structure containing insulating fluid, baffle means disposed in said casing and movable therein from a normal position to an operated position, a passage in said baille means arranged so that iluid in said casing is caused to flow through said passage in response to movement of said baille means within said casing structure, a xed contact in said casing structure, a movable contact movable with said baille means and disposed with respect to said passage so that the arc drawn between said xed and movable contacts upon separation thereof is subjected to a ilow of said fluid through said passage, Venting means in said casing adjacent the region in which the arc is drawn for relieving pressure developed by the arc, said casing being otherwise substantially closed and said venting means being disposed with respect to the region in which the arc is formed so that substantially equal pressures due to the arc are transmitted through said passage to opposite surfaces of said baffle means.

7. An electric circuit breaker comprising casing structure lled with insulating liquid, bafiie means disposed in said casing and movable therein from a normal position to an operated position, spring means biasing said baille means toward its operated position and operable to move said baille means to its operated position during opening of said breaker, a passage in said baille means arranged so that the liquid in said casing is caused to ow through said passage in response to movement of said baie means toward its operated position, a pair of relatively movable contacts disposed with respect to said passage so that the 8 arc drawn therebetween upon separation thereof is subjected to a flow of said fluid through said passage, venting means in said casing adjacent the region in which the arc is drawn for relieving the pressure developed within said baille means by the arc, said casing being otherwise closed and said venting means being disposed with respect to the region in which the arc is formed so that substantially equal pressures due to the are are transmitted through said passage to opposite surfaces oi' said batiies means.

WILLIAM E. PAUL.

References Cited in the me o! this patent UNITED STATES PATENTS Number Name Date 2,219,171 Balachowsky Oct. 22, 1940 2,271,989 Prince Feb. 3, 1942 2,442,010 Leeds et ai May 25, 1948

Images