US2933576A - Circuit interrupters - Google Patents

Description

April 19, 1960 R. E. FRIEDRICH ETAL 2,933,576

cmcun zm-zanupms Filed Oct. 3, 1958 7 Sheets-Sheet 1 mun INVENTORS Robert E. Friedrich and RusBsYeIl N. Yeckley. J 24% f M v AfTORNEY P 19, 1950 R. E. FRIEDRICH ETAL 2,933,576

CIRCUIT INTERRUPTERS Filed Oct. 3, 1958 7 Sheets-Sheet 2 APril 1960 R. E. FRIEDRICH ETAL 2,933,576

CIRCUIT INTERRUPTERS 7 Sheets-Sheet 3 Filed Oct. 3, 1958 April 1950 R. E. FRIEDRICH ET AL 2,933,576

CIRCUIT INTERRUPTERS 7 Sheets-Sheet 4 Filed Oct. 3, 1958 April 1960 R. E. FRIEDRICH ETAL 2,933,576

CIRCUIT INTERRUPTERS 7 Sheets-Sheet 5 Filed Oct. 3, 1958 April 19, 1960 R. E. FRIEDRICH ErAL 2,933,576

CIRCUIT INTERRUPTERS 7 Sheets-Sheet 6 Filed Oct. 3. 1958 II LJ lll'l Lllllllll I is U I I I I ,4 .61 I m K L l I 05G} I my:

April 1960 R. E. FRIEDRICH ETAL 2,933,576

CIRCUIT INTERRUPTERS 7 Sheets-Sheet 7 Filed 001;. 3, 1958 United States Patent CIRCUIT INTERRUPTERS Robert E. Friedrich, Baldwin, and Russell N. Yechiey, Monroeville, Pa., assignors to Westinghouse Eiectric Corporation, East Pittsburgh, Pa., a carporatien of Pennsylvania Application October 3, 1958, Serial No. 765,173 11 Claims. or. 200-448 This invention relates to circuit interrupters in general and, more particularly, to arc-extinguishing structures and piston assemblies therefor.

With the rapid growth of the electrical industry in recent years and consequent system expansion, some existing sub-transmission or middle voltage 46 kv. systems have virtually become distribution systems supplying power to industrial and distribution substations. This change in the basic use from bulk power supply to local power supply can be expected to become more prevalent with continued load growth. It is, therefore, necessary to provide equipment for sectionalizing lines to eliminate or minimize outages on these circuits.

Power circuit breakers manufactured to conform to present standards assure more interrupting ability than is required, and are, therefore, under most circumstances, uneconomical for this application. The automatic circuit recloser for these higher voltage distribution systems, de signed for lower interrupting capacity, is fundamentally lower in cost and at the same time provides other ad vantages.

In U.S. patent application, filed September 14, 1956, Serial No. 609,915, by Robert E. Friedrich, entitled Circuit interrupter, and assigned to the assignee of the instant application, there is described and claimed a novel circuit-interrupter construction particularly adapted for the middle voltage circuits, such, for example, as those from 23 to 69 kv. It is a general object of the present invention to improve upon the interrupting ability of the circuit interrupters described in the aforesaid application, by associating with such a circuit interrupter a piston assembly, which is adapted to effect purging of the contaminated or heated gases within the interrupting chamber during the closing operation of the interrupter.

Another object of the present invention is to provide an improved piston, or puffer assembly for a fluid-blast circuit interrupter, which is of compact size, simple and effective in operation, and is readily adaptable for inclusion in the interrupting structure of fluid-blast circuit interrupters.

Another object of the present invention is to provide an improved piston assembly for a fluid-blast circuit interrupter, in which means are incorporated to increase the speed of travel of the piston vane relative to the speed of operation of the contact structure, so as to provide an increased volume of fluid flow into the arcing chamber to eiiect purging of the arced gases therein.

Although the piston or putter assembly disclosed in the present invention has applicability to any type of fluid-blast circuit interrupter, it has particular applicability and advantage when applied to a circuit interrupter utilizing a substantially enclosed arcing chamber, which is vented with some diificulty. For example, in the type of circuit interrupter employing two arcs in series, one of which is a pressure-generating arc and the other being an interrupting are, necessarily the surrounding interrupting chamber must be substantially closed, so as to utilize the pressure effectively resulting from the thermal expansion of the gas. It has been found that in such types of circuit interrupters there may exist the possibility of local high-temperature regions.

Development testing of fluid-blast circuit interrupters, particularly those of the gas-blast form of the selfpressure-generating type, has indicated a decrease in interrupting performance during consecutive tests, using short-time intervals between tests, in particular multiplereclosings. The decrease in interrupting ability on multiple-reclosings has been found to be caused by the formation of a less dense gas in the interrupter chamber. During interruption, arcing heats the gas in the interrupter chamber. Operations immediately following will not allow enough time to permit the dissipation of this heat by natural means, such as convection or conduction.

Since the interrupting chamber is connected to the volume of the circuit interrupter, the result is that the substan-,

tially enclosed arcing chamber contains gas at normal pressure, elevated temperature and decreased density.

Since interrupting performance is a function of density,

this condition of decreased gas density within the substantially enclosed interrupting chamber will result in a lowering, or a drop in interrupting ability. 1

it is, therefore, a further object of the present invention to provide an improved puifer assembly, which will function in conjunction with a circuit interrupter to purge the arced gas within the substantially enclosed interrupt ing chamber.

in the specification and in the accompanying claims, it is to be understood that the term fluid includes gases, liquids, vapors and sprays. For purposes of illustration, however, and not by way of limitation, the present invention will be described as applied to a 46 kv. relatively low-capacity circuit interrupter adaptable for multiple reclosing duty, and utilizing as the arc-extinguishing fluid sulfur hexafluoride (SP sulation and arc-interrupting characteristics of sulfur hexafiuoride are described in detail in U.S. Patent No. 2,757,261, issued July 31, 1956, to Harry J. Lingal, Thomas E. Browne, In, and Albert P. Strom, and assigned to the assignee of the instant application.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

Figure 1 is a front elevational view of a three-pole automatic circuit recloser, embodying the principles of the present invention;

Fig. 2 is an enlarged side elevational view, partially in vertical section, of one of the pole-unit assemblies, the contact structure being illustrated in the closed-circuit position;

Fig. 3 is a vertical sectional view through the arcinterrupting unit of the pole-unit assembly of Fig. 2;

Fig. 3A is a plan view of the apertured valve plate disposed wlthin the interrupting chamber to prevent reverse flow to the piston assembly;

Figs. 4 and 5 are enlarged sectional views taken substantially along the lines IV-IV and V-V, respectively, of Fig. 2, the contact structures being shown in the closed-circuit position;

Fig. 6 is an enlarged side elevational view of the put for assembly employed in the pole unit of Fig. 2;

Fig. 7 is an end sectional view of the puffer assembly of Fig. 6, taken substantially along the line VII-VII of Fig. 6, with the movable parts being illustrated in the closed-circuit position;

Fig. 8 illustrates a modified type of puller assembly, which may be applied at the upper end of a pole-unit assembly, such as ilustrated in Fig. 2, taking the place of the upper cap assembly; and,

Fig. 9 is a top plan view, in section, of the modified Patented Apr. 19,1960

The remarkable in;

' sesame iii the line IX- IX thereof, with the'contact structure being illustrated in the closed-circuit position.

Referring to the drawings; and more particularly tov l thereof; it will bev observed, that the circuit interrupter of" the present invention is illustrated as of' the automatic circuit-recloser type, and is generally designated'by the reference numeral 1. Generally, the circuitf interrupter 1' includes three pole-unit assemblies, designated by the reference letters A, B, and C in Fig. 1; The'poleaunit assemblies A, B and C are identical instructure, and, therefore, a description of the operatingfeatures of one ofthe pole-unit assemblies willsuf ficefor anunderstanding of the operation, of" all three off them.

notediinlii g, l, the polerunit"assembliesrmhi and. 0,". are supported upon. a pairof" spaced; horizontally $3.5 tcud'ing angle irons 2,] only 'one ofiwhich is illustrated' in. Fig, 1". Grounded" mounting plates- 3, composed of;

sheet steel; are fixedly secured between the horizon:

tally extendiug angleirons 2', resulting in a rigid structure. Disposed" at the right-hand end of. the circuit interrupter 1', asviewed in Fig, 1; is a. mechanism compart-- ment 4, secured to apair of'channelmembers 5, 6, which may be welded below the angle irons 2.

Generally, the mechanism compartment 4 houses a 'closingsolenoid; notshown, which serves to actuate a horizontally extending operating rod, which extends horizontally through pipes 7-, interconnecting the several pole units. The horizontally extending operating rod is suitably linked to the operating mechanism 8 (Fig. 2) associated with each pole-unit assembly. Thus, should any pole-unit assembly be tripped open upon overl'oad, or by the passage of fault current, the solenoid, withinithe mechanism compartment 4, will be ac tuatedso as to move the horizontally extending operating rod, within pipes 7; to the. right, effecting thereby contact-.reclosure in oneor. more pole unitsjwhich have. been. opened by thefault current. If any pole unit as semhly'has opened, thersolenoitlmechanism.will be effective. toclosethat pole-unit-assembly, which has opened,v the other two pole unit assemblies remaining closed. A.

preferable type. of operating mechanism for the automatic'circuit recloser 1, herein illustrated, is set out and claimed in U.'S.' patent application filed December 24, 1956} Serial No. 630,304, by Roswell C; Van. Sickle, Fritz'*'E. Florschutz and Joseph Sucha, and assigned to the assignee of'the instant application.

The solenoidme'chanism, disposed Within. mechanism compartment4; is efi'ective to reclose. the. pole units a number of times following repeated. reopening, before. an intgator, not shown, functions to; prevent further reclosing acti'on of. the: solenoidimechanism, and permits the pole-unit'assemblies to remain open. A manually operable trip lever 9' may be. manually engaged by an operator with ahook stick, and'this will eifect, through suitable-linka ge', horizontal movement of a second hori z-ontally extending. rod, also passingthrough pipes 7, which will trip the mechanism. 8" associatedv with each pole-unit assembly.

' ignated by the reference numeral 15, and including an fully With particular reference. to, Fig, 2 of. the. drawings,

it'iwilllbe noted that each pole-unit. assembly includes a single terminal bushing, which may, be. of. the. condenser. type, generally designated by the reference numeral 10, a mechanism housing 11' enclosing a current transformer 12, and anioperating mechanism 8". As observed in Fig. 2; theterminal bushing 10 andthe mechanism housing ll' d'epend from-the grounded mountingplate' 3, the lat tenrestingupon-v the spaced angle i'rons'2, as hereinbefore described.

In. addition, each pole-unit assembly includes an upstanding; Weatherproof, insulating casing 13, preferably composed. of; a: suitable. weatherproof. material,- such. as porcelain. The insulating, casing 13 encloses, in a gasettg-htmanner, aninterrupter assembly,,generally desarc-extinguishing unit 17' and a rotatable contact structur'e 18.

Enclosing the upper open end of the hollow porcelain casing 13 is a-cap structure, generally designated by the reference numeral 1?, and including a mounting terminal plate 28, in this particular instance composed of'aluminum, and a cap casting 21, also: composed of aluminum. The cap structure. 21 supports a pressure gauge 22, a valve 23 and a rupturedisc' 24. The mount= terminal plate it) has. a terminal pad extension (Pig. 2) for the accommodation of a transmissiondine cable.

With particular referenceto. Fig. 2 ofthe drawings, it will be observed that the terminal. bushing 19 is clamped by means, not shown, to the grounded mounting plate 3 and extends therethrough, through an opening 25, and has the interior. end of the. terminal stud 2'? thereof received betweena pair of. contactfingers 2%. As set out in detail in the aforesaid patent; application Serial No. 609,915, the contact. fingers, 23' arehiased toward each other by a compression spring, surrounding a bolt and. are spaced apart by a surrounding spacing sleeve,

not shown.

The contact fingers Eli are enclosed within a substantially T-shaped bracket member i4,fsecured by bolts to an insulating support plate iii, in a manner more disclosed in the aforesaid Friedrich application.

. As shown more clearly in Fig. 7 of the drawings, the inwardly biased clamp-type contact fingers 39 of the finger assembly, 23 make resilient engagement with a contact sleeve 32 surrounding an insulating tubular drive shaft 33. The contact sleeve 32 extends upwardly through the insulating support plate 31, and, above the plate 31 has clamped thereabout a rotatable contac -arm casting 34, as illustrated in Fig, 5 of the drawings. With reference to Fig. 5, it will be observed that the contact arm casting 34 has a clamping bifurcated portion 34a, which is. clamped about the contact sleeve 32 bya'. bolt 35' and a nut 36.1 The, configuration of the contact arm 34 isapparent from a study of Figs. 2 andS' of the draw mgs. I g V At the outer free extremity of the contact arm 34 is a rotatable interrupting contact 37, which makes abutting, resilient, contacting engagement with a relatively stationary interrupting contact 38 (Fig. 3). The shank portion 39 of the relatively stationary interrupting contact 38 has a helical contact pressure spring 40 disposed 'thereabout, which bearsatoneend withina cup-shaped" recess 41 provided inv the inner side wall of an insulating tubular interrupting chamber; 42. The outer'end' of' the contact. biasing; spring 40 bears .against 'a' cup-shaped washer 43, which surrounds the shank'39 of1contact38 and is maintained in position by" a locking ring 44 (Fig. 3.).

it will be noted, with reference to Fig. 3 that there are.

provided two such relatively stationarycontacts 38, 45,

of. substantially identical construction, which are electrically and mechanically interconnected externally of the interrupting chamber 42 by an intermediate contact plate 46, which hasopenings 47 (Figs. 4 and 5) provided generating contact 49, more clearly shown in-Figs; 2 and 4 of the drawings. Therotatable movable pressure-generating contact 49 constitutes the outer' freeextremity ofa contact casting arm 54}, which, as-was'the case with contact-arm casting 3'4, encircles and'cl'ampingly engages acontact sleeve 51. (Fig. 2) disposed adjacent the upper end of the. tubular insulating drive. shaft 33.. Arelative- 1y stationary, rotatablelcontact, bar, pivotally mounted.

, on a conducting pivot to the underneath side of the terminal mounting plate 20, not shown, is biased laterally against the upper contact sleeve 51 in a manner illus trated in detail in the aforesaid, Friedrich application, and provides a means for electrically interconnecting the contact sleeve 51 with the terminal plate 26.

In the closed-circuit position of the circuit recloser A, the electrical circuit extending therethrough traverses terminal mounting plate 20, contact bar, not shown, bearing against contact sleeve 51, contact arm casting 50, rotatable pressure-generating contact 49, relatively stationary pressure-generating contact 45, intermediate contact bar 46, lower relatively stationary interrupting contact 38, rotatable movable interrupting contact 37, contact-arm casting 34, contact sleeve 32, resiliently biased fingers 30, Fig. 2, contact portions 28 of the resilient fingers to terminal stud 27 (Fig. 2) of terminal bushing 10. The lower extremity 53 of terminal stud 27 is connected to the other distribution line.

During the opening operation, the tripping latch 9 may be pulled downwardly by a hook stick. This will effect release of the energy stored within an opening accelerating spring, disposed interiorly within housing 4, to effect lateral movement of an operating rod, not shown, extending laterally through the interconnecting pipes 7 and connected to the several operating mechanisms 8 A, B, and C.

The mechanism 8 associated with each pole unit will effect rotative motion of a crank-arm assembly 54 (Fig. 2) supported from the mounting plate 3 and coupled by a pin-and-slot coupling 55 to the lower end of the insulating tubular drive shift 33.

The rotative opening motion of the tubular drive shaft 33 will effect consequent rotative opening motion of the pressure-generating and interrupting contacts 49, 37, respectively. The relatively stationary contacts 45, 38 will follow the movable contacts 37, 49 for a short distance, as provided by the springs 40 until-the intermediate contact bar 46 abuts the external wall of the tubular interrupting chamber 42. When this occurs, the rotatable movable pressure-generating contact 49 will establish a pressure-generating arc 56, as indicated in Fig. 4 of the drawings. In a similar manner, the movable interrupting contact 37 will establish an interrupting arc 57, as indicated in Fig. 5 of the drawings.

It will be observed that the rotatable movable pressure-generating contact 49 does not unplug from an orifice member 58 secured through an opening 59 in the side wall of the tubular interrupting chamber 42, so that consequently the pressure of the gas within region 60 within tubular chamber 42 rises because of thermal expansion. The rise of pressure within region 60 forces gas, in this particular instance sulfur hexafluoride (SP under pressure, out of the interrupting orifice 61 provided by an orifice member 62 likewise secured through an opening 63 of the tubular interrupting chamber 42. The rapid expulsion of gas under pressure out of the interrupting orifice 61 quickly effects extinction of the interrupting are 57, and consequently the electrical circuit passing through the recloser A is interrupted.

In the fully open-circuit position of the recloser A, the rotatable contact castings 34, 50 attain the open-circuit position, indicated by the dotted lines 64, 65 as shown in Figs. and 5, thereby providing two isolating gaps serially into the circuit.

As mentioned hereinbefore, testing has revealed during consecutive tests, with short intervals of time between tests, that is, during multiple reclosing operations, that local high-temperature regions within region 60, interiorly of tubular interrupting chamber 42, result in a lowering of the density of the gas within the interrupting chamber 42, and that this brings about a lowering or a drop, in the interrupting ability of the recloser 1.

To remedy this condition, the present invention is conas manually effected,

associated with the pole units.

6 cemed with associating with the interrupting chamber 42 a piston or a puffer assembly generally designated by the reference numeral 65 in Fig. 2, and more clearly illustrated in Figs. 6 and 7 of the drawings.

The puffer assembly 65 generally includes a piston vane 67 (Fig. 7) having a substantially rectangular configuration, which is secured by a plurality of bolts 68 and nuts 69 to the tubular insulating drive shaft 33, so that it rotates therewith. A piston chamber, generally designated by the reference numeral 70, is provided by a pair of substantially identical end plates 71, 72 having an external configuration more clearly shown in Fig. 7 of the drawings. Each of the piston- chamber end plates 71, 72 has a circular mounting opening 73 therethrough, to accommodate the tubular drive shaft 33. Since the drive shafe 33 is fixed in position, and merely rotates, it will be apparent that the drive shaft 33 assists in fixedly supporting the insulating end plates 71, 72, and consequently, the piston chamber 70 as a whole.

An arcuately-shaped plate 74 extends longitudinally of the piston chamber 70 between the end plates 71, 72, and the outer free end 75 of the rectangularlyshaped piston vane 67 slides therealong having a rather close sliding fit therewith. The side plate 74 has openings for dowel pins 76, which assist in maintaining the side plate 74 in the proper position. Another plate 77 extends longitudinally of the piston chamber 70 and is likewise maintained in position by dowel pins 76. The plate 77 has a plurality of circular openings 78 extending, in alignment, lengthwise thereof, which register with a plurality of side bores 79 (Fig. 7) provided in a longitudinally extending insulating support plate 89. The plate 80 has an elongated end bore 81 bored through the end thereof, which interconnects with all the several bores 79, thereby constituting a manifold gas passage. The common manifold gas passage 81 is extended, by an insulating sleeve 82, which fits into a recess 83 provided in the insulating support plate 31, as shown in Fig. 6 of the drawings.

Tie-rods 84 extend lengthwise of the piston chamber 70 and, with spacing sleeves 85, 85a and nuts 85b maintain the entire puffer assembly 65 in a fixed stationary position relative to the support plate 31.

To insure unidirectional fluid passage through the piston vane 67, the latter is provided with an elongated slot 86 (Fig. 7), which may be closed by an elongated valve plate 87. Two bolts 88 pass through the ends of the elongated valve plate 87, and also pass through openings 89 of the piston vane 67. Helical springs 90 and nuts 91, surrounding the two bolts 88, provide biasing means 92 for biasing the elongated valve plate 87 closed over the elongated slot 86 in the piston vane 67.

From the foregoing description, it will be apparent that the piston chamber 70 is defined by portions of the end plates. 71, 72 the two longitudinally extending side plates 74, 77 and the rotatable piston vane 67 itself. During the opening operation of the interrupter, the tubular drive shaft 33 rotates in a counterclockwise direction, as indicated by the arrow 93 in Fig. 7. This draws gas through the elongated slot 86, the valve plate 87 opening. During the closing operation of the interrupter, the tubular drive shaft 33 rotates in a clockwise direction, as indicated by the arrow 94, and this compresses the gas within region 95 within piston chamber 70, closing the valve plate 87 and forcing the compressedgas to flow through the openings 78 and through the registering bores 79, in longitudinally extending plate 80, to the common manifold gas passage 81, extending lengthwise through plate 80. The gas passes in the direction indicated by the arrows 96 in Fig. 7 and lengthwise through the common manifold passage 81, as indicated by the arrows 97 in Fig. 6. The compressed gas then passes through connecting sleeve 82 and through I off tubular: interrupting chamber 42'.

. extremity of the recloser.

anemone an. opening;-

in. mounting plate: 3!; and; into then end.

With reference tov Fig: 3 of the drawings, it will be noted that disposedinteriorly within the lower end of tubular interruptingcliamber 42 area pluralityof apertured circular insulating plugs 99, 1G0, 191, and 102. A circular valve plate 16 (Fig. 3A) is movable within a recess A3 provided in insulating plug member 101. The valve plate 16 has a plurality of circumicrentially d1sposed valve openings 104,-which are closed when the valve plate 16 is in its lower position, as illustrated in Fig. 3. i

During the opening operation of the recloser A, the pressureof the. gas within the region 66, interiorly of' tubular interrupting chamber, 42, is sufi'cient' to maintain the circular valve plate 16 in its lowermost position. within circular recess103, as 'illustrated in Fig. 3'. Gravity assists:inzthispositioning of corcular valveplate 16. Are interruption takes place in the manner previously described, and, with referenceto Fig. 7, it will u be noted that counterclockwise rotation of piston vane 6? during the opening operation will open valve plate 37 andrecharge; the interior 95 withinpistonchamber 7h with fresh gas.

lilu ring the: closing operation of therecloser A, the tubular insulating. drive shaft 33 rotates, in a clockwise direction, as indicated by the arrow 94. in Pig. 7-. This will not only effect contact'reclosure within interrupting chamber 42, but, in addition, the clockwise rotative movement of piston vane. s7 will force compressed, fresh gas in the direction. indicated by the arrows 97 (Fig. 6) into theiregion' 135 (Fig. 3). The compressed gas within region 1951Willl force circular valve plate 16 upwardly, against. the. forcexof gravity, so that the gas may now pass through the circumferentially disposed openings 104 and into the interior all of the interruptingchamher. 42. This fresh gas,.provided by: the piston assembly, will purge the arc'ed' or contaminated and heated gas out of the interrupting chamberv 42; and will provide therein fresh gas of high density in readiness for a. subsequent opening operation.

A particular advantage of the. foregoing construction is that since the putter assembly operatesduring the clos- 7 ing operation, it does not have to act against the arcing pressure, and, therefore, requires less mechanical effortfor operation. Also, the puffer action, during theclosing operation, will aid in the;v prevention of long pre strikes during the closing strokes. A prestrikef isiarcing. betwcenthe approaching contacts'during aclosing oper.

ationof the recloser due to the voltage'thereacross.

Figs..8 and 9. illustrate: a modification of the invention in which the cap. structure 10, illustrated in Figs. i and 2 of the drawings is omittedandin place thereof a modified cap structure 107 is substituted therefor at the upper Fig. 8, illustrates a modified type of terminalmounting plate 29a, from which the tubular interrupting chamber 42a depends, in amanner similar to that illustrated in'Fig. 2 of the drawings. It will be noted that the modified cap structure Iii?" constitutes a' generally circular piston chamber 108 (Fig; 9) within which a rotatable piston vane, or wing, H59 rotates. The piston wing'109 is laterallysecured to a vertically extending. supporting rod 110 having an upper reduced end portion 111 journalled' within a" recess 112- provided in top plate 113. The lower end ofsupporting rod 110 has a reduced shank portion 114, which ex= tendsthrough an opening 1l5'provided' in a piston-chamher end plate ltd. Pinned to the lower extremity of us duced.v shank portion 114 of supporting rod 110 is a pinion gear 117, which meshes withagearsegment 118' pinned to a rotatable drive shaft 119 in a manner more clearly shown in Fig. ofthe drawings. Asshown,

the drive. shaft 119. isjournalled within a depending sleeve. portion 120: of: piston end plate- 116.

- ment E518 and rotation of piston wing within piston chaitnberv 1%.

With reference to-Fig; 8, itvn'll lie-observed that'an insulating'sleeve 121* extends between openings 1-22 provided' in" piston end plate 116 and an opening 123 pro= vided in modified terminal mounting plate 20a. The upper and of interrupting chamber @241 has a plurality of members 12442.27 which support the circularvalve plate 123-, biased to. its upper closed position by a light;

helical. compression spring 12.). The valve 'plate 128' ality of openingsuse as did the valve plate- A V The fundamental" operation or modified piston ass seinhiyilfit illustrated in Figs. 3' and 9 is identical to that of the piston assembly d5 inPigs. 6' and 7' of'the draw ingsg' namely during the opening operation of the recloser A, arcing-pressure withinrcgion so niaintainsvalve plate 128' in its upward closed position. During this time, rotation of the tubular drive shaft 35 7 effects, through the-multiplying gears 117, M8, charging rotation of tlie'piston' wing 169-, the latter having a springbiased valve plate 87, the same as the piston vane 67 the arrangement shownin' Fig; 7 of the drawings; During the closing operation, the rotative' motion of drive shaft 33, indicated by arrcw ii in Fig. 9, not only effects contact reclosure within interrupting chamber 42a; but also', through the multiplying gear segment 1'18 effects driving movement o'f pisto'n vane 1329 to, force gas to flow in the direction of the arrows E31 through connecting sleeve 121 to force valve plate 128 to its lower: most openposition. The lowering of valve plate 3528 will permit the compressed gas to flow from the niodilied piston assembly 330' into" the upper end of tubular.

interrupting chamber: 424:; and thereby effectv therein a purging"of thecontaminated and heated arced'; gases.

From the foregoing description of two modifications of the invention,- it will be apparent that the puller as sembly of tie present invention provides an eiiective means to purge high-temperaturearcedgases/cut of the arcing chamber, and to replace them with relatively high-density gas in readiness for subsequent opening operation. As a result, there is. no possibility of local high-temperature regions within the interrupting chamber 42,42a, and insurance is obtained that the arcingchamr ber contains gas of the same densityfla's is' contained hroughout the interior of the circuit'reclo'ser. As a re sult', during multiple reclosings, effective circuit interrup- 7 closing operation does not have to act against the arcingpressure, and therefore-the mechanical effort required for operation'of' thepuilerassembly is a minimum.

It will be obvious to those skilled in the artthatthe present invention is applicable to" any typeof circuit interrupten. However, particular advantage is obtained by an application of the present'inventiorr to interrupt= ing structuresprovided with substantially-enclosed arcing" chambers, in which there is some ditlicultyin rapidly're plenishing the gas therein due to the substantially enclosed" construction; Particularlyis thistrue in the caseof' multiple-break, interrupting structures involving a, pressure-generating arc in series" with an interrupting arc, in which interruption takes place in a substantially enclosed" arcing chamber; Since a' substantially enclosed interrupting chamber is employed, difiiculty is obtained in replenishing the gas during successive interruptions;

'and' arr application of the present inventionv remedies 9 this. situation. Insurance is bad that fresh gas is-swept into the arcing chamber during the closing stroke prior to each opening operation, gas of relatively low density rupting chamber.

It will also be readily perceived by those skilled in the art that the present invention may be employed in interrupters using different mediums than gases. For example, liquid-break interrupters may, with advantage, use the piston assembly of the present invention. Merely for purposes of illustration has the present invention been described as applied to a gas-type of circuit interrupter.

Although certain piston or puffer assembly constructions have been illustrated, it is to be clearly understood that the same were merly for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the invention.

We claim as our invention:

. 1. In a circuit interrupter, contact means cooperable to establish an are, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, piston operating means for effecting opening and closing motion of said movable piston within said piston chamber, unidirectional-acting valve means associated with said movable piston to effect is ejected out of the interfluid-driving effort only during the closing movement of the movable piston and relatively free non-driving motion of the piston during the opening movement thereof, and means correlating said piston operating means with said contact operating means so that driving piston motion occurs within said piston chamber during the closing operation of the interrupter whereby relatively fresh fluid is forced adjacent said contact means during such closing operation of the contact means.

2. The combination in a circuit interrupter of contact means cooperable to establish an arc, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, fluid passage means interconnecting said piston chamber with the region about said contact means, unidirectional acting valve means disposed within said fluid passage means preventing fluid flow through said fluid passage means toward said piston chamber, piston operating means for effecting opening and closing motion of said movable piston within said piston chamber, unidirectional-acting valve means associated with said movable piston to effect fluid-driving effort only during the closing movement of the movable piston and relatively free non-driving motion of the piston during the opening movement thereof, and means correlating said piston operating means with said contact operating means so that driving piston motion occurs within said piston chamber during the closing operation of the intercepter whereby relatively fresh fluid is forced against said contact means during such closing operation of the contact means.

3. A circuit interrupter including means defining an interrupting chamber, contact means disposed within said interrupting chamber and cooperable to establish an arc therein, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, fluid passage means interconnecting said piston chamber with the region about said contact means within said interrupting chamber, piston operating means for effecting opening and closing motion of said movable piston within said piston chamber, unidirectional-acting valve means associated with said movable piston to effect fluiddriving efiort only during the closing movement of the and that high-temperature movable piston and relatively free non-driving motion of the piston during the opening movement thereof, and means correlating said piston operating means with said contact operating means so that driving piston motion occurs within said piston chamber during the closing operation of the interrupter whereby relatively fresh fluid is forced adjacent said contact means during such closing operation of the contact means.

4. A circuit interrupter including means defining an interrupting chamber, contact means disposed within said interrupting chamber and cooperable to establish an arc therein, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, fluid passage means interconnecting said piston chamber with the region about said contact means within said interrupting chamber, unidirectional acting valve means disposed within said fluid passage means preventing fluid flow through said fluid passage means toward said piston chamber, piston operating means for effecting opening and closing motion of said movable piston within said piston chamber, unidirectional-acting valve means associated with said effort only during the closing movement of the movable piston and relatively free non-driving motion of the piston during the opening movement thereof, and means correlating said piston operating means with said contact operating means so that driving piston motion occurs within said piston chamber during the closing operation of the interrupter whereby relatively fresh fluid is forced adjacent said contact means during such closing operation of the contact means.

5. A circuit interrupter of the fluid-blast type including means defining a substantially enclosed interrupting chamber, serially related contact means disposed interiorly within said substantially enclosed interrupting chamber separable to establish a pressure-generating arc and a serially related interrupting arc, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, fluid passage means interconnecting said piston chamber with the region about said contact means within said substantially enclosed interrupting chamber, piston operating means for effecting opening and closing motion of said movable piston within said piston chamber, unidirectional-acting valve means associated with said movable piston to effect fluid-driving effort only during the closing movement of the movable piston and relatively free non-driving motion of the piston during the opening movement thereof, and means correlating said piston operating means with said contact operating means so that driving piston motion occurs within said piston chamber during the closing operation of the interrupter whereby relatively fresh fluid is forced adjacent said contact means during such closing operation of the contact means.

6. A circuit interrupter of the fluid-blast type including means defining a substantially enclosed interrupting chamber, serially related contact means disposed interiorly within said substantially enclosed interrupting chamber separable to establish a pressure-generating arc and a serially related interrupting arc, operating means for said contact means operable to effect closure of said contact means during the closing operation of the circuit interrupter, a piston assembly including a piston chamber and a movable piston movable therein, fluid passage means interconnecting said piston chamber with the region about said contact means within said substantially enclosed interrupting chamber, unidirectional acting valve means disposed within said fluid passage means preventing fluid flow through said fluid passage means toward said piston chamber, piston operating means for effecting opening and closing motion of said movable piston withmovable piston to effect fluid-driving mass ve i tempting chamber, and valve means carried by said atingmeans so that driving piston motion occurs within said piston chamber during the closing operation ot'the interrupter whereby relatively fresh fluid is forced adja-,

cent said contact means during such closing operation of the contact means.-

7. A fiuid-blast circuit interrupter including a rotatable drive shaft, movable contact structure carried by said" rotatable drive shaft, relatively stationary contact structure cooperable with said movable contactstructure to establish arcing, operating means for effectingopening and closing rotative movementof, said rotatable-drive shaft, means defining a piston chambenapiston vane so cured to said drive, shaft and operable within said piston chamber, passage means connecting said piston chamber with the region about said contact structure, and valve means carriedby said piston vane to effect fluid' driving motion of said pistonvane only during the closing rotative' movement of said drive shaft.

8". A fluid-blast circuit interrupter including a rotatable drive shaft, movable contact structure carried by said rotatable drive shaft, relatively stationary contact structure cooperable with said movable contact structureto establish arcing, operating means for efiecting opening and closing rotative movement of said rotativedriveshaft, means defining a piston chamber, apiston vane secured to said drive shaft and operable within said piston cham ber, passage means connecting said piston chamberwith'; the region about said'contactstructure, valve means carried by said piston vane to effect fluid driving motion of said piston vane onlyduring the closing rotativemove-= ment of said drive shaft, and unidirectional acting valvemeans disposed within. said passage means to prevent reverse flow* of fluid through said passage means toward said pistonchamber pending high-pressure conditions during the" opening operation.

9: A fluid-blast circuit interrupter including a hollow cylindrical insulating casing, a terminal bushing having one end thereof projecting into one end of said hollow insulating casing, a rotatable drive shaft projecting into thesameend of said hollow insulating casing, means delining an interrupting chamber disposed adjacentthe other end-of said hollow casing, movable contact structurecarried. by said drive I shaft and'movable intosaid" interrupting chamber, relatively stationary contact structure disposed interiorly within said interrupting chamber and cooper able with said movable contact structure to establisharcing within said interrupting chamber, a piston assembly including a piston wing carried'by said drive shaft'and 'apiston chamber having apair of piston chamber end plates, said piston chamber end plates having openings" therein through which said drive shaft" extends, passage: means interconnecting said piston chamberwith said inpiston vane to-eife'ct fluiddriving motion of said piston" vane only during the drive shaft. I a

10. A fluid-blast circuit interrupter including a hollow cylindrical insulating casing, a terminal bushing having one end thereof projecting into one end of said hollow insulating casing, a rotatable drive shaft projecting'into the same end of said hollow insulating casing, means closing rotative movement of said defining an interrupting chamber disposed adjacent the other end of said hollow casing, movable contact structure carried by said drive shaft and movable into said inter= rupting chamber, relatively stationary contact structure disposed interio'rly within said interrupting chamber and cooperable-with said movable contact structure to estabiis arcing within said interrupting chamber, a piston asembly including a piston wingcarried by'said drive" shaft and apiston chamber having a pair of piston chamber'end plates, said piston chamber end plates having openings-- therein through which said drive shaft extends, passage means interconnecting said piston chamber with said interrupting' chamber, valve means carried by said" piston vane to effect'fluid' driving motion of said pistonvaneonly during the closing rotative movement of said drive shaft;

andunidirectional acting Valve means disposed Within said passage meanstoprevent reverse flow offluid throughsaid passage means toward said piston chamber pending lngh'pre'ssure conditions during the opening operation;

1 1. A fluid blast circuit interrupter including a hollow" cylindrical insulating casing, a terminal bushing havingone end thereof projecting into one end of said hollow in sulating casing, a rotatable drive shaftprojectingintothe same end of said hollow insulating casing, means defining aninterrupting, chamber disposed adjacent the other end -01? said hollow casing, movable contact structure carried by said drive shaft and movable into said interrupting chamber, relatively stationary contact structure disposed" interiorly within said interrupting chamber and cooperable with said movable contact structure to establish arcing within said interrupting chamber, a piston assembly dis posed adjacentsaid otherend of said hollow insulatingcasing; the piston'assembly including a movable pistonand: apiston chamber, meanscorrelating movement'of said piston with said rotatable drive shaft sothat rotation of; said. drive shaft will effect movement of said" piston within said pistonrcharnber, passage meansinte'rco'nnecting;

said. piston. chamberfwith said interrupting chamber, and,

valveameanss carried. by said pistonv vane to effect fluid? drivingjmotiontof. said piston vane only during the closing rotativemovement of. said drive shaft.

References Qitedin the fileof this patent UNITED I STATES FATENTS} 2,850,600 a Prince Sept. 2,1958v FOREIGN PATENTS 310,618 Switzerland e Ian. '14, 1956*

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