CA1077549A - Nozzle-type compressed-gas circuit-interrupter having gas-inlet orifices - Google Patents

Abstract

NOZZLE-TYPE COMPRESSED-GAS CIRCUIT-INTERRUPTER HAVING GAS-INLET ORIFICES

ABSTRACT OF THE DISCLOSURE
An improved nozzle-type compressed-gas circuit-interrupter is provided, either of the puffer-type, involving relative piston-and-cylinder motion to produce gas pressure, or, alternatively, using a high-pressure gas-reservoir source for injecting gas through a nozzle, whereby improved and advantageously-located gas-inlet orifice structures are associated with the said nozzle, so that gas may be injected into the arc at a plurality of inwardly-directed orifice openings provided in the nozzle structure itself.
Preferably, some of the gas-inlet orifices are directed downstream of the orifice constriction region so that the gas-inlet passages, or orifices direct a plurality of relatively cold gas jets inwardly into the established arc adjacent its downstream portion located within the insulating nozzle structure.
In one embodiment of the invention, the nozzle structure is movable, being attached to a movable operating gas-compression cylinder, which slides relatively over a stationary piston structure and compresses gas therebetween.
In another embodiment of the invention, instead of using a piston-and-cylinder gas-compression arrangement, gas may be supplied from an outside high-pressure gas-reservoir chamber, as well known by those skilled in the art of compressed-gas circuit interruption.

Description

CROSS-REFERENCES TO RELATED PATENTS
Re~erence may be made to Unlted States patent NoO 3,9~7,262 issued October 19 9 1976, ;'`

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~775~Lg to Joseph Rostron, entitled "Puf~er~Type Gas-Blast Circuit- ;
Interrupter Having Variable-Area Stationary Composite Piston Structurel'. Additionally, reference may also be made to United States Patent No. 49139,751 issued February 13i 1979 to Joseph Rostron et al, entitled "Improved Pu~fer-Type Compressed-Gas Circuit-Interrupter'l, both o~ said U~S. patents being assigned to the assignee of the present application.
BACKGROUND OF THE INVENTION
The present invention is particularly related to pu~er-type compressed gas circuit-interrupters of the type in which o~ly a single gas pressure level is utilized within the interrupting structure, and a di~ference of gas pressure ~or arc interruption is achieved by pis-ton action, that is, relative movement of an operating cylinder to a piston structure. Attention may be directed to United States patents: 3,839,613 - Tsubaki et al; ~,602~670 - Calvino Teijeiro; 3,849,616 - Calvino Teijeiro; 3,670~124 - Calvino Teijeiro; ~t670,125 - Calvino Teijeiro; and 3,712,969 - Calvino Teij eiro.
As well known by those skilled in the art~ the relative motion between the movable operating cylinder assembly and the ~ixed piston achieves a desirable compression of gas within the compression chamber therebetween, which compressed gas is utilized during arc interruption by generally ~orcing the said compressed high-pressure gas through a movable hollow insulating nozzle structure to direct the ~77~49 ~:

high-pressure gas flow intimately into effective engagement with the established arc drawn within the movable insulating nozzle throat to effect the latter's extinc-tion.
DESCRIPTION OF THE PRIO~ ART
The present invention relates to puffer-type cir-cuit-interrupters of the type set forth in U.S. Patent 3,551,623, issued December 29, 1970, to Robert G. Colclaser, Jr. and William H. Fischer. This patent shows the relative motion of a movable piston within a relatively stationary operating cylinder, with electromagnetic coils energizing a companion movable piston, which is electrically repelled toward the first-mentioned movable piston, the latter being attached to, and movable with, a contact-operating rod.
As well known by those skilled in the art, there are many patents treating different piston structures, for ~-. :.!
.~l example, U.S. Patent 2,429,311, issued October 21, 1947, to - M. J. Gay; and U.S. Patent 3,786,215, issued January 15, ~ 197~ to Gerhard Mauphe.
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An additional patent of interest in connection 20 with piston structures is U.S. Patent 3,331,935, issued July 18, 1967 to Stanislaw A. Milianowicz. Another piston patent, : j :
utilizing hydraulic action for effecting piston action, is U.S. Patent 2,913,559, issued November 17, 1959, to Charles F. Cromer.
An additional patent of interest is German Patent 671,326 patented in Germany October 1937. All of the afore-said patents indicate that piston structures of the prior art are well known, but many have deficiencies of complexity and of being rather slow in operation. In addit:ion, back-pressure gas conditions may easily arise, which renders the 46,250 : ~ ~775 .

lnterrupter, as a whole, relatively ælow-acting in operation, generally taking several cycles to effect circult interruption.
BRIEF SUMMARY OF THE INVEN~ION
According to the present invent~on, an improved lnsulating nozzle structure is provided, which is preferably, although not necessarily, movable, and attached to a movable operatlng gas-compression cylinder, which slldes over a stationary piston structure compressing gas therebetween. A
plurality of gas-inlet passages, or orifices are provided within the body portion of the insulating nozzle, so as to direct gas into the arc stream at least by means of a plurallty of inwardly-directed ~ets, or orifices downstream of the arc, which is drawn within the insulating nozzle structure.
:~, :1Also, desirably, additional gas-inlet orifices are provided at the most constricted portion of the nozzle. Th~s desirably results in a mixing of the cold arc-extinguishing gas, such .: . ...
` as sulfur-hexafluoride ~SF6) gas, for example, into the arc stream so that a desirable mixing of the gas with the arc stream occurs within the nozzle, and al~o, preferably, ~ :`
.i20 downstream of the nozzle to thereby effect rapid arc extinction.
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Another embodiment of the invention utilizes, -alternatively, instead of a piston-and-~ylinder gas-compression arrangement, high-pressure gas emanating from an outside high-pressure gas-reservoir chamber. Also~ the insulating nozzle may be either movable, as mentioned hereto-fore, in connection with a puffer-type circuit lnterrupter, or, alternatively, said insulating nozzle structure, having the gas-inlet passages, or orifices provided ~herein, may be stationary, and the contact s~ructure so arranged as to draw an arc interiorly through the fixed insulat.ing o:ri.fice 46,250 , ~775i~g structure itself. The important feature of the instant invention t~ be born in mind is the location and dlrection of the gas-inlet ~ets, or orifices, which are provided :; withln the body portion of the insulating nozzle. Whether the nozzle is ~ixed or movable is immaterial.
~ BRIEF DESCRIPTION_OF THE DRAWINGS
;, Figure 1 is a vertical sectional view taken through one embodiment of the present invention, illustrating a gas-blast puffer-type circuit-interrupter with the separable ~;~ 10 contacts illustrated in the closed-circu$t position;
., Figure 2 is a detailed sectional inverted plan view taken substantially along the line II-II of Figure 1 ~; looking in the direction of the arrows;
.:.3j Figure 3 is a view similar to Figure 1, but illus-: ,;
trating the disposition of the several component parts ln .'1 the partially-open-circuit position of the circuit-interrupter during the early stages of arcing;
:~, Figure 4 is a fragmentary sectional view illus-.
trating a later stage of arcing;
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., 20 Figure 5 illustrates the circuit-interrupter in "
the fully-open-circuit position;
Figure 6 is a fragmentary, sectional inverted plan view taken along the line VI-VI of Figure 5.
Figure 7 illustrates a modified metall:Lc tank form o~ the invention utilizing a pair of electrically serially-rela~ed arc-extinguishing units disposed within a grounded metallic tank structure in which the improved insulating nozæle of the invention is relatively fixed in position for each of the two arc-extinguishing units;
Figure 8 is an enlarged vertlcal sectional view . 46,250 ',. ''.~,' ~77549 `:

taken through one of the arc extinguishing units of Figure ; 7, the contact structure being illustrate~ ~n the closed- ~.
circuit position;
Figure 9 is a fragmentary sectional view, somewhat s$m~lar to that of Figure 8, but illustrating the arcing ~ .
condition of the circuit-interrupter;
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Figure 10 is a fragmentary detailed sectional view .^ of thç common blast-valve controlling the downward flow of ;, ~ :-,, oompressed-gas through the two conduits interconnecting the compressed-gas tank with the two lower-disposed arc-extin-- guishing units o~ Figure 7;
~;~ Figure 11 illustrates, to an enlarged scale, a :
,,, ~'! vertical sectional view taken through the improved insulating nozzle of the present invention, the structure conforming to ~ that set forth in Figures 1-6 o~ the drawings; and, :,' J~' Figure 12 is an inverted plan sectional view o~
;~1 the insulating movable nozzle o~ Figure 11. ' !
DESCRIPTION OF THE PREFERRED EMBODIMENTS
: Referring to the drawings, and more particularly to Figures 1-6 thereof, it will be observed that there is , provided a puffer-type compressed-gas circuit-interrupter 1 havlng an upstanding insulating casing structure 2, which is provlded at its upper end with a metallic dome-shaped con~
ducting cap portion 3, the latter supporting, by means of a bolt 4, a line-terminal connection Ll. Extending downwardly ~ :
interiorly of the conducting dome-shaped casting 3 within the casing structure 2 is a relatively-statio~ary contact structure, designated by the reference numeral 6, and cooper-able in the close~-circuit position of the interrupter with a movable contact structure 7, as illustrated more clearly -6- .

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~775~1 in Fi~ure 1 of the drawings. The movable contact structure 7 is electrically connected, by a plurality of sliding ring con- ~:
: tacts 9, to a generally horizontally--extending conducting sup-~`~ port plate 10, which provides a second line terminal L2 exter-nally of the casing 2, as again shown more clearly in Figure 1.
'. A suitable operating mechanism 12 of conventional orm effects rotation of an externally provided crank-arm .~. 13, the latter effecting opening and closing rotative motions ~, of an internally-disposed operating æhaft 14. The operating shaft 14, in turn, is fixedly connected to an internally-, ~' disposed rotative crank-arm 16, which ls plvotally connected, as at 17, to a floating link 18, the latter being pivotally :~
, connected, as at 19, to the lower end o~ a linearly-movable contact-operating rod 20.
~:~ It will be noted that the upper end of the contact ~il operating rod 20 forms the movable contact 7 itself, which, i~ . as mentioned heretofore, makes contacting closed-circuit engagement with the stationary contact structure 6 in the closed-circuit position of the interrupting device 1, as 20 illustrated in Figure lo `' A movable operating cylinder assembly 22 is provided having a large-diameter, downwardly-e~tending movable sleeve portion 24~ which slidably moves over a relatively-fixed piston structure 26, as again illustrated ln Figure 1.
During the opening operation 7 it will be observed that the movable operating cy].inder 22 moves downwardly over the relatively-fixed piston structure 26 compressing gas 28 within the region 30, and forcing it to ~low upwardly through -~
the vent openings 32 and through the relatively short nozzle 33, through which the arc 3ll is drawn) as shown in Figures . 46,250 ~L~775~9 :

3 and 4.
Figure 2 more clearly shows an inverted plan sectional view taken through the movable operating cylinder22, indicating the wide venting area 40 in vent openings 32 to provide unimpeded flow of the high-pressure gas 28 from .;: the compression region 30 within movable operati-ng c.ylinder ... 22 upwardly through the large vent openings 32 and into and ` through, the movable nozzle structure 33, where arc-extinction , ,~ .
quickly takes place.
The stationary main contact fingers 42 make con-; tacting engagement in the closed-circuit position, as illus-` trated in ~igure 1, with an annular main movable contact portion 44. During the opening operation of the puffer lnterrupter 1, the main stationary contact fingers 42 part contact with the annular movable main contacting portion 44, so that thereafter contact is only maintained between the stationary tubular arcing ccntack 46 and movable arcing contact fingers 48, as i.llustrated ln Figure 1~
Downward continued opening motion of the conducting operating rod 203 as effected by the operating mechanism 12, continues to force the movable operating cylinder 22 down-wardly over the stationary fixed piston structure 26, thereby providing an upward flow of compressed gas 28 through the movable insulating nozzle 33. It will be observed that a : downwardly~extending annular movable boss portion 50 enters a stationary cavity 52 provided generally centrally of the relatively-fixed piston structure 26, and thereby provides a mating closing interengagement between the two structures to thereby minimize the "dead" volume of gas 28 within space 30. This is deisrable inasmuch as a higher gas-compressi.on 46,250 .

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. , ratio.is thereby achieved~
Dur~ng the closlng operation of the puffer inter-rupter 1, the movable operating cy~inder 22 moves upwardly9 ~ and carries w7th it the annular main movable contact 44 .~ together with the movable arGlng fingers 480 First, a con-. tact~ng interengagement is made between the tubular stationary arcing contact 46 and the circular cluster of movable arcing . fingers 48~ This contacting interengagement prevent.s a subsequent prestriking condition occurring between the main ,~1 10 stationarg ~ontact fingers 42 and the main annular movable :1 contact portion 44, Thus~ there is no prestriking o~ the arc occu.rrlng or perm~tted whatsoever at the main stationary contact fingers 42 and the annular main mova.ble contact 44~ :
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all prestriking being confined to the stationary tubular ,j ~
arcing contact 46 and the movable arcing contact probe 54 to prevent any arc erosion occurring at the main contacts 42, The gas-~low path taken by the compressed gas 28 through the movable operating cylinder 22 and the movable - 20 insulating nozzle 33 presents an efficiently-shaped contour, with steadily decreasing gas-flow area reaching the minimum, or criti~al flow area only at the nozzle throat 56.
The present invention particularly relates to structural improvements in the interrupting insulating .
nozzle 33 of single-pressure, puffer-type circuit-interrupters 1 of the type set forth in Figure lo The arc-`. quenching capability of the insulating improved orifice structure 33 of the present invention is enhanced through the in~ection of cool gas 28 into the hot arc plasma 34 resulting in a more rapid recovery of dielect:ric strength of _g_ ., 46~2~0 7~
, the arcing region 38, which can result in shorter arcing times and~or the withs~and af a high~r rçaovery voltage ~ Qllowing interruption.
!,,:.,'~ The interrupter struc~ure 1, includin~ the nczzle 33, is illustrated in Figure 1, and c~mprise~ e~sentially a ~;` moving cylinder contact assembly 22 movable over a stationary fixed piston 26. The moving ~ylinder contact assembly 22 ,.~^.
; oomprises a ~oss portiDn 50, to which the moving finger ,-',, contacts 48, arc horn 54 and movable operating rod 20 are ~` }O clamped. The interrupter nozzle 33 iq fixed ~o the movable operati~ ¢ylinder 22.
~`~ On the opening operation, the gas 28 i8 compressed within a compression volume 30 contained between the stationary Piston 26 and the moving operating cylinder 22 and flows through the supporting spider apertures 32 a~d through the movable ~ozzle orifice 33.
We have discovered that long downstream divergent nozzles are more effective as 3F6 circuit-interrupters.
~om~ 1phO~Dgr~ p227 C g t22d 7 ~3 ~29D h~Y~ 9~D~n~ ~n ~D7De c~Be~ a~ :
least, an early loss o~ luminescence at the downstream portion, or exit end of the movable nozzle 33. Investig~tion has found th~t a cold in~ection of gas molecules 28 into a hot arc plasma 34 results in a more rapid cooling, mixing and deioniæation. Recent analysis, a~ain points ouk the e~fect~veness of the downstream portion 33A o~ the nozzle 33 in arc interruption. This invention propose~ to in~ect cold SF6 gas 28 into this downstream region 33A, resulting in a more effective interrupter 1.
The gas 28, compressed by the moving cyll.nder 22, 30~ moves throu~h a plurality o~ provided openings 53 into the ~ 46,25Q

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' circumferential manifold 59, which communicates with a plurality of tubular openings 60 and 61 in the insulating nozzle 33, which in~ect the cold gas 28 into the downstream portion 33A of the movable nozzle 33a resulting in a more ~ rapid recovery of dielectric strength.
.-; Although shown as an adaption to a puffer-type circuit-interrupter 1, this additional ~et flow principle applies equally well to any gas-type circuit interrupter ;` utllizing axial blasting of arcs 34, both single and doubIe . 10 ~low.
Fig~re 7 illustrates an alternate form of the .
invention in which an insulating nozzle structure 63 is sta-tionary instead of movable, and instead of a fixed piston and mo~able operating cylinder arrangement to provide a compressed-gas fIow 28 through the nozzle, instead high-pressure gas 28 is taken from a high-pressure gas-reservoir, or chamber 65, illustrated in Figure 7. A common blast-valve 70, illustrated in Figure 10, controls the flow o~
high-pressure gas 28 from the high-pressure reservoir 65, 20 through a conduit 71 and through a pair of lower-disposed ~ ~.
branch feed-pipes 73, 74 to a pair o~ arc extinguishing units 75, which are electrically interconnected by a vertically-movable conducting crossbar 80. The fully-open circuit position of the conducting cross-bar 80 is designated by the dotted lines 83 in Figure 7.
Figures 8 and 9 illustrate more in detail the structural arrangement in which the arcing probe 54~ the main stationary contact 44A and the arcing fingers 48A are . all stationary and cooperate with the elements heretofore shown as movable in Figures 1-6, namely movable tubular 46,250 ~ 75~ ~

arcing contact 46A, movable main contact flngers 42A, consti-tuting a movable contact structure, herein deslgnated by the reference numeral 90.
As shown in Figures 8 and 9, the movable contact structure 90 is rigidly affixed to the extremlty of the con-ducting aross-arm, or movable traverse member 80.
During the opening operation~ suitable means, not shown, effe¢ts a simultaneous downward opening movement of the movable crossbar 80, establishing two serially-related arcs 101 (Figure 9) established within the two arc-extinguishing units 75, the two collectlvely being more clearly illustrated in Figure 7. Simultaneously, with the : downward opening movement of the mo~able cross-arm 80, `
establishing the two arcs 1019 there also occurs upward mavement of the blast-valve 110 (Figure 10), permitting thereby a downward blas.ting of high-pressure gas 28 ~rom the high-pressure reservoir chamber 65, downwardly through the two ~onduits 73, 74, and into the two arc-extinguishing units 75. The flow of the gas blast 28 is designated by the .~ 20 arrows 115.
; A possible type of blast-valve operating mechanism is set forth in U.S. Patent 3,284,6023 issued November 8, ' ~ 1966 to ~riedrich et al, which could be used.
l Arc extinction occurs within each of the units 75 : in the manner described heretofore, except thatg obviously, the piston-and-cylinder arrangement 26, 22 is not utilized, : and instead reliance is placed upon the blast valve 110 and .~ the high~pressure gas 28 stored wlthin the high--pressure gas-reservoir chamber 65. Otherwise, the interrupting 30 features are the same as described heretofore~ consequently, -12~

46,250 ." .
~775~9 a further description thereof is deem.ed unnecessary. As ~-before, the cold ~ets 62 of a suitable gas, such as sulfur-hexa~luoride (SF6) gas~ is utilized, passlng khrough the two sets of stationary auxiliary orifices 60, 61 2nd into the resp ec t~ ve ~ 57 constriçted and downstream~exhaust areas 56'oi~ the nozzle :
structure 63.
From the foregoing descriptiona it will be apparent that there has been provided an improved insulating nozzle orifice structure 33, 63 having gas-i~let passages 60, 61 provided advantageously in khe body portion of the insulating orlfice. Preferably, the gas inlet passages 60, 61 termlnate not only downstream of the arc plasma, but, additionally, at the constricted portion of the nozzle itself, designated by the re~erence numeral 56.
Although two forms o~ the invention have been illustrated, one utilizing a "puffer-typel' of piston-cylinder ~as-compression arrangement 22 for providing a compressed gas flow, nevertheless, the principles of the nozzle structure 33, 63 are applicable, where desired, with , ,:
~.~ 20 a high-pressure gas source issuing from a high-pressure gas '~. reservoir, or chamber 65. Also, it is immaterial whether the nozzle structure 33 is fixed or movable, this being merely a matter of choice.
Also, where desired, double-flow gas action through bath separable contacts may be employed, that is the movable contact structure 7 in Figure 11 may exhaust arced gas through the movable operating rod 20, which in this case would be a tubular vented operating rod (not shown).

Although there have been illustratecl and described specific structures, it is to be çlearly understood that the -13~

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same were merely for the purpose o~ illustration, and that changes and modifications may readily be made therein by tho$e skilled in the art, without departing from the splrit .
and scope of the in~ention.

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Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are fefined as follows:

1. A compressed-gas type of circuit-interrupter including means defining an insulating nozzle having a most-restricted portion, means for establishing an arc through said insulating nozzle, means for providing a main gas-flow through the insulating nozzle and axially against the estab-lished arc, and separate independent freely-flowing gas-flow means terminating inwardly at said most-restricted portion for providing a plurality of freely-flowing auxiliary separate gas-inlet passages for forcing relatively cold independent jets of gas into the said arc throughout the interruption operation of said most-restricted portion and into the downstream portion of the nozzle.

2. me combination according to claim 1, wherein the insulating nozzle structure is movable being attached to an operating cylinder, and the latter sliding over a relatively-fixed piston structure to generate gas flow under pressure.

3. The combination according to claim 19 wherein a high-pressure gas-reservoir chamber is utilized to force gas through the insulating nozzle, and the insulating nozzle is relatively fixed in position.