US2604562A

US2604562A - Electric circuit interrupter

Info

Publication number: US2604562A
Application number: US73614A
Authority: US
Inventors: William E Paul
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1949-01-29
Filing date: 1949-01-29
Publication date: 1952-07-22
Anticipated expiration: 1969-07-22

Description

July 22, 1952 w, 5 PAUL 2,604,562

ELECTRIC CIRCUIT INTERRUPTER Filed Jan. 29, 1949 3 Sheets-Sheet 1 I Fig.1.

III IIIZ Inventor: William E. Paul,

His Attorney.

July 22, 1952 w. E. PAUL 2,604,562

ELECTRIC CIRCUIT INTERRUPTER Filed'Jan. 29, 1949 3 Sheets-Sheet 2 Fig.4.

Inventor: William E. Paul,

by His Attorney.

w. E. PAUL 2,604,562

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His Attorney.

July 22, 1952 ELECTRIC CIRCUIT INTERRUPTER Filed Jan. 29, 1949 able valve members disposed within the housing Ill. The insulator contains the fluid conduits from the valves disposed within the housing l and also serves as a means for supporting the longitudinally extending structure comprising the interrupting units 6, the exhaust chamhers I, and the insulators 8.

The constructional details of the interrupting units 6 and of the exhaust chambers 1 are shown in Fig. 2. Each interrupting unit 6 is housed within a hollow weather-proof insulator |2 which preferably is constructed of porcelain or other suitable inorganic ceramic material. The insulator I2 is held in position between the two metallic end plates |3 to which are secured the metallic flanged rings l4 which engage the insulating material l5 to hold the insulating tube I2 securely in place. Disposed within the insulator I2 is the interrupter casing comprising a base plate l6 and a top plate Also, a back plate l8, best shown in Fig. 9, and a front plate similar thereto are secured to the plates l6 and l! to complete the structure for enclosing the interrupting contacts I9 and 20. All these plate-like members are made from some suitable inorganic are resistant insulating material such as fibre. Contacts l9 and 20 are of the hinged type and are pivotally supported at the fixed pins 2| and 22 to the stationary conducting

studs

23 and 24 which may be integral with the two metallic flange plates 25, which in turn are provided with extending edges which engage the insulating gasket 26a. The

studs

23 and 24 are normally held in the position shown by means to be described hereinafter. Conducting

studs

23 and 24 are embedded within the

insulating blocks

21 and 28 which preferably are secured to the metallic plates 26 in any suitable manner. To aid in supporting the

blocks

21 and 28 and to aiford a partitioning structure for separating the downstream and upstream portions of the interrupting unit 6 from each other, the two lower plates Mia and the two upper plates Ila are appropriately secured to the plates |3 to the back wall l8, and to the front wall 25. Plates |6a and Na preferably are constructed of insulating material. A wedge-shaped barrier 29 is disposed within a central opening in the top plate H. The wedgeed of a homogeneous gas-emitting insulating material, such as polymeric methyl methacrylate or the like, so as to afford good insulation in all directions as well as possessing good are extinguishing characteristics. Longitudinally extending exhaust passages 30 branch on either side of the wedge-shaped barrier 23. These passages serve to divert exhaust gases from each interrupting unit 6 to the adjoining exhaust or expansion chambers The hinged contacts l9 and 20 are embedded within or otherwise united to the generally semicircular nozzle blocks 3| and 32, which blocks are of appropriate insulating material and are rotatable about the pivots 2| and 22 which are disposed at the geometric cen ter of the arcuate portion of the periphery thereshaped barrier 29 preferably should be constructspective pivots 2| and 22.

shown in Fig. 8 may be used. It will be observed that the contact 20 is provided with a projection 20a which engages the portion [3a of contact 9, thereby affording a somewhat yieldable engagement between the contacts due to resiliency of the portion I94: and of the projection 20a. Long wipe is achieved by constructing contact I! with two finger-like projections |9b which remain in engagement with the outer surfaces of the projection 28a after contact has been broken between portions 19a and projections 2311 thereby maintaining the circuit through the contacts l9 and 20 until a predetermined contact opening movement of the contacts has occurred.

In order to insure resilient electrical contact between the pivotally movable contacts [9 and 20 and their respective stationary conducting

studs

23 and 24, the structure shown in Fig. 5 has been found desirable. Both the contacts I3 and 23 are pivotally supported in the same manner, the details of which will be described in connection with contact |9. As shown in Fig. 5, the pivot pin 2| is secured to the conductor I9 by the rivet or pin 21a. The two prongs 23a of the bifurcated conducting stud 23 are provided with aligned openings which form journal supports for the outer ends of the pivot pin 2|. Formed integrally with the prongs 23a of conducting stud 23 are a plurality of conducting fingers 23b which are adapted to engage the outer surface of the shaft pin 2| by a relatively high pressure contact. In this way, shaft pin 2| is freely rotatable in response to movement of the contact l9 and at the same time high pressure contact is maintained between the conducting stud 23 and the shaft pin 2| by means of the fingers 23b so that arcing and resulting pitting of the engaging surfaces is avoided.

In order not to impede contact opening rotation of the hinged contacts l9 and 20 and their nozzle blocks 3| and 32,

recesses

35 and 36 are respectively formed in the nozzle blocks 3| and 32 which together with corresponding pockets in the supporting

blocks

21 and 28 form clearance chambers. Air is not entrapped in these

chambers

35 and 36 for it is allowed to escape by way of

vents

31 and 38 leading downstream therefrom. However, a small amount of air may be entrapped for contact cushioning by arranging the vents as side ports from the clearance chambers at some appropriate lateral point toward the stroke end as shown. Thus the pockets and the cooperating recesses form dashpot means which is effective after the

surfaces

35a and 36a respectively close the

vents

31 and 38.

Pressure air or gas admitted through the common supply conduit 58 to the lower portion of each interrupting chamber in the region below the nozzle blocks 3| and 32 will exert a substantially simultaneous contact opening force on the several co-acting pairs of nozzle blocks 3| and 32 which rotate mutually about their re- The engaging arcuate surfaces 3|a and 32a of the nozzle blocks 3| and 32, when the contacts are in the closed position shown in Fig. 2, are so arranged that a predetermined angular rotation of the nozzle blocks 3| and 32 is necessary before such engaging surfaces will be separated. Thus the in-flowing gas blast will build up pressure to accelerate opening movement of the contacts I9 and 2|! some time before pressure fluid is allowed to pass between the nozzle blocks 3| and 32. Thus, there I is no tendency for pressure fluid to accumulate in the upper portion of the arcing chamber in the region immediately surrounding thewedgeshaped barrier 29' until after-the contacts have achieved a relatively high velocity opening movement. For this reason, the interrupting units are not choked with pressure fluid before interruption of the arc and fluid is not wasted due to premature blasting. While high velocity opening movement of the contacts l9 and is being achieved, the relatively straight cut-away portions 31?) and 32b of the nozzle blocks 3| and 32 wil1 rotate to produce eventually a passage for the stream of pressure fluid directed between the nozzle blocks 3| and 32. The space between the portions 3lb and 32b is gradually increased as nozzle block 31 rotates counterclockwise and as nozzle block 32 rotates clockwise. After high pressure, high velocity, fluid flow has been established between the nozzle blocks 3| and 32 and outwardly through the widely divergent exhaust passages 30, the are drawn is blasted by the high velocity fluid against the wedge-like deflector 29 and the products of arcing flow through the exhaust passageways 36 into the expansion space within the chambers I.

From the above description, it will be understood that I initiate the are at the point of incidence of the applied fluid blast and then elongate the are by drawing both roots in generally opposite directions by virtue of the mutually rotasloping surfaces of the deflecting gas-emitting barrier 29. Thus, a very effective are extinguishing process ensues by virtue of the concentrated blastdirected toward the mid-portion of the are which presses the latter forcibly against the gasemitting surfaces of the deflector 29. Accordingly, the arc is assailed not only by a fresh stream of high-pressure cool uncontaminated air or gas issuing from between the nozzle blocks, but it is also subjected to a secondary gas blast treatment upon its opposite side which is automatically generated from the gas-emitting walls of the deflector 29 along which the arc has been drawn by the arcing contacts and against which it is being immobilized by the force of the fluid blast. As the contacts mutually rotate away from one another to thereby draw an arc of increasing length, the nozzle blocks inner periphery gradually recede from one another to produce a blast nozzle of increasing cross-sectional area whose flnal configuration is illustrated in Fig. 7. Accordingly, I have provided means for producing an extinguishing blast, the intensity or magnitude of which varies in accordance with arc length.

Furthermore, it will be observed that the arcing contacts l9 and 20, in their final open position as shown in" Fig. 7, lie fairly in the middle of the laterally divergent ventpassages so that the full length of the arc, from its central portion to its either extremity at the arcing contacts l9 and 26, is subjected to a blast of high pressure extinguishing gas which has been diverted into twodiverging streams in 'a manner highly effective for preventing re-establishment of the extinguished arc across these separated electrodes terrupting unit 6 between plates l3 and 26.

arcuate' sweep; enhancing tips of the -'-inter'-' rupting contacts-l9 and 20. In thismanner', the arc will become subjected to the direct pressure blast and the reactive emitted blastsubstantially instantaneously upon its inception. v

As the contacts open, thefe'ontour' of the divergent exhaust passages about the deflecting wedge 29 remains substantially unchanged because of the aforementioned truly 'arcuate' configuration of the upper portions 3lc' and 320 of intermeshed by other well-known means for achieving mutual movement for a part or throughout the whole of thejco'ntact travel.

Thefexhaust chambers 1., best'shown in Figs. 2 and ,4, comprise an outer metallicweather protective casing 40 which is providedwith a plu reality of lcuvers 4 I for allowing the escape of exhaust gases. An appropriately configured partition wall 42 segregates the; cylindrical casing 40 into a generally U-shaped exhaust or expansion chamber43 which communicates direct- 1y with the passageways 30 and'another chamber 44 within the U in which is housed a toggle connector generally designated by the numeral 45. Thetoggle 45' comprises a longer link 46, a short s'haftj41 at'theknee of the; toggle, and a shorter link 48. Secured to or integral with the shorterlink 4'8 isahandlemembe ,4 which has an extension Siladapted to engagethe link 46 forstopping and holding the toggle in its overset position as shown in Fig. 2. It will be apparent that counterclockwisemovement of the handle 49 will break the toggle and relieve the end thrust produced by the toggle when in its overset position shown. Because I make the toggle. members, ofjhard copper or othe r good conducting metal, they constitute an electrical connection as well as an efiective'thrust member between adjacent units. Thus, good contact making pressure is exerted between the

links

46 and 48 and the cooper'ating conducting studs 23 and.24,- and because the plates 26 are secured to the

studs

23 and 24, pressure is exerted on gaskets 26a to prevent leakage of fluid from in- In order to removethe toggle connection, the handle 49 is rotatedin the counterclockwise direction which will collapse the toggle and make possible its ready removal-from the chamber 44 through the door 5i. After the toggle connector has been remo'vedythe assembly '52 comprising the contact 20'an'd its nozzle block-32, the conducting'stud24, thevcontact reclosing spring 34, the

supporting block 28;-an'd its plate 26 may readily be withdrawn from the interrupter structure downwardly out through the casing door 5!.

In Fig. 3, I have shown an ordinary jack-screw comprising the cooperating members-54 and 55 of good conducting metal which may be used as a thrust type connector insteadof thetogg1e 7 connector 45 comprising the

links

46 and 48. It will be understood that, by means such as these, all the interrupters are electrically connected together in series relationship.

For the purpose of supplying pressure fluid to the interrupting units 6 from the pressure reservoir 9 and also for operating suitable disconnecting switches, the structure shown in Fig. 6 may be used. Pressure fluid for opening the contacts [9 and 20 and for blasting the arc drawn therebetween passes from reservoir 9 through the blast valve 56, conduit 51, into inlet passage 58 which is in communication with the lower portion of the several interrupting units 6. Blast valve 58 may be electromagnetically controlled either manually or automatically in any well-known manner.

Because the

contacts

19 and 28 will automatically reclose after the blast valve 55 is closed, due to the action of compression springs 33 and 34, it is necessary to provide suitable isolating switches arranged in series relationship to the interrupter units, the opening of which preferably would be initiated simultaneously with or shortly after the opening of blast valve 55. For example, the isolating

switch rods

59 and 60, which cooperate with contacts BI and 62, are disposed within the insulators 8.

Switch rods

59 and 60 are moved inwardly to the open position by pressure fluid passing from reservoir 9 through the opening control valve 63, insulating conduits 64 and B and being applied to pistons 66 and 87. Opening valve 63 may be electromagnetically operated and should be arranged to open somewhat after the opening of blast valve 56 in order to insure that the interrupting action will have been completed before permitting the isolating gap to form. Thus pressure fluid admitted through the insulating supply conduit 51 and the distributing conduit 58 will separate the contacts [9 and 20 and blast the are drawn therebetween to extinction before the isolating

switch blades

59 and 60 will have disengaged their cooperating contacts 6| and 62. Because the interrupting contacts l9 and 20 will reclose upon the cessation of the fluid blast under the urge of their return springs 33 and 34, it will be appreciated that the blast valve must be properly timed to reclose so that a safe isolating gap or gaps have been opened up before the interrupting contacts are permitted to reclose.

For the purpose of closing the isolating contacts, a short fluid blast may be supplied through insulating

conduits

51 and 58 to the interrupting contacts l9 and 20 so as to separate and blast these contacts momentarily while the

isolative contacts

59 and 60 are closing. Therefore, simultaneously with, or just after, the opening of blast valve 58 for this purpose, the closing control valve 68 is opened and pressure fluid is supplied to the right-hand surface of piston 66 and to the left-hand surface of piston 51 to produce closing motion to the

contact rods

59 and 60 so as to engage the contacts BI and 62. As clearly indicated in Fig. 6, the closing valve 68 controls an insulating conduit 69 which branches into an insulating conduit leading to the closing end of the fluid motors. In order to make sure that pressure fluid is not trapped in back of the pistons as they perform contact opening and closing movements, suitable bleed ports may be provided such as those shown at Hand 72 within the conduits l0 and 65, respectively. or if desired the valves 63 and- 68 could be constructed with exhaust ports leading to atmosphere when the valves are closed.

From the above description, it is apparent that each pair of interrupting contacts l9 and 20 disposed within each interrupting unit 6 and the isolating contacts disposed within the insulators 8 are independently operable. By proper adjustment of

springs

33 and 34 on all the interrupting units 5, the contacts l9 and 20 of all the interrupting units may be made to operate substantially simultaneously even though pressure within conduit 58 may not be the same throughout its entire length. Due to the particular construction of the nozzle blocks 3! and 32 and the resulting rapid opening of the

contacts

19 and 20 and because of the sliding cooperation between the isolating contact rods 59 and 50 and their cooperating contacts GI and 82 and the resulting relatively slow opening of these contacts, a multiple-break interrupter is provided which will open its independent interrupting contacts substantially simultaneously and almost instantaneously and which will insure that the isolating contacts are opened after all of the interrupting contacts have been separated. Furthermore, the entire mechanism is enclosed and hence free from diificulties due to icing.

It should be noted that rapid reclosures on this breaker may be effected by having the isolating control valve 63 energized through a notching relay, for example, so that the isolating contacts 55? and need not be moved at all, until a given number of automatic reclosures of contacts l9 and 20 have been made by means of the biasing springs 33 and 34 and then reopened by again automatically tripping valve 56 from overcurrent. Valve 56 of course will automatically reseat at cessation of current after each interruption. By this means, the necessary time required for accelerating the isolating switches between operations is eliminated. Only after the desired number of reclosures have been made will the valve 63 be energized and final isolation occur, until the system is again reset.

In accordance with the modification of my invention shown in Figs. 10 and 11, the isolating function is performed by causing the interrupting contacts and the structure associated therewith to separate by an appreciable distance so as to form between the contacts an adequate isolating gap. The interrupter shown in Figs. 10 and 11 comprises the exhaust chamber generally designated by the numeral 14 and the interrupting chamber generally designated by the numeral 75. Support for the interrupter is provided in the form of a hollow insulator 16 which preferably is constructed of ceramic material and which may be generally similar to the insulator H of Fig. 1. Metallic foundation disc 11 is secured to the upper flanged end of insulator 16 by means of the bolts 18 and their cooperating clamps 19. The outer wall of exhaust chamber '14 comprises a cylindrical metallic casing 8| provided with exhaust louvers 82. An internal chamber 13 is disposed within the casing 81 and comprises the

metallic side walls

83 and 84, the bottom wall 85 as well as front and back walls 88 and 86a. Casing 8| is flanged at each end and is secured at its lower end to the foundation plate 11 by means of bolts 11a. The plate 81 is secured to the upper flange on the casing 8| by means of bolts 88 and their cooperating clamps 89 which in turn cooperate with the flange on the lower end of the ceramic shell 90 which forms a weather protecting enclosure for the interrupting chamber I5. The bolts 80 may be utilized as one terminal of the interrupter. As shown, the shell 90 may be corrugated in order to increase the creep'age path along the surfaces of the shell so as to prevent flash-over. Disposed at the upper end of the shell 90 and secured thereto by the bolts Eli and the clamps 02 is a metallic disc 93. A cover member'constructed of metal and designated by the numeral Si is secured to the plate 93 by means of bolts 95. If desired, the cover member 93 may be provided with any suitable terminal means such as is indicated at 96 to form another terminal of the interrupter.

The structuredisposed Within the insulating shell 90 and comprising the interrupter unit is' similar to the structure shown in Figs. 2 and '7 except that the lower contact 03 and its associated structure is adapted to move longitudinally downward to perform an isolating action. The

uppercontact does not move bodily, and hence its associated insulating block 80 is bolted to plate 03 by bolt Insulating plates 09 are fixed in position to block 80 by any suitable means.

insulating block 91 and plates I00 are secured together to form a unitary movable structure I IS. A tongue and groove construction as indicated at IOI is provided to insure a substantially fluidtight junction between the abutting surfaces of plates 09 and I00 and between blocks 00 and 97. The contacts I02 and I03 are pivoted to the shaft pins I04 and I05, respectively, and are embedded within their corresponding rotatable nozzle blocks, I05 and I01. The contacts and their nozzle blocks are biased toward the closed position shown by means fo the compression springs I08'and I 09.. The shafts I04 and I05 are journally supported by the plates 99 and I00, respectively. The shaft I04 is electrically interconnected with top plate 93 by the conductors 80a which are bolted to plate 93 by bolt 98 and which are provided with openings at their lower ends through which shaft pin I04 extends. Shaft pin I05 is connected to middle plate 01 through the flexible conductor I00a.

Fluid pressure for operating the contacts I02 and I03 together with their coresponding nozzle blocks is admitted from a source not shown through the valve V3, the conduit H0 which extends through the

plates

11, 85 and 81, and into the lower end of the inlet passage I I I formed in block 91., Fluid from conduit through the passageway III, operates the con tacts, and extinguishes the arc. Exhaust passage IIZgformed within block 80 serves to convey the products of the interrupting operation through the opening II4 to atmosphere. Exhaust passage II3 leads to the opening IIE', thence into the space between the cylindrical casing BI and the walls of chamber I3. This blast escapes from the shell 8| to atmosphere through the louvers 82. The portion H8 of the exhaust passage between the passage I I 3 in block 91 and the opening II 5 is formed by the metallic member II! which is bolted to the block 9"! and'is slidable along the wall 83.

' The unitary structure generally designated by thenumeral H9 and comprising'blo'ck 91 and plates I00 together with contact I03 and nozzle block I01 is held in the position shown by the latch I23 which engages the lower surface of the back plate I00. The latch I23 is maintained in the closed position by the action of spring I24 and is movable to the open position by fluid pressure admitted to the cylinder I25 which is efiective to operate the piston I26 against the.

I I0 passes action of spring I24. Cylinder I25 is secured within a; recess in the plate 81 by means of the ears I21 and bolts I28 shown dotted in Fig. 10. Ears I21 may be welded to cylinder I25. Fluid pressure for opening the latch I23 is admitted to the cylinder I25 through conduit I29 and valve V1 from a source of fluid pressure, not shown.

A circuit opening operation of the interrupter of Figs. 10 and 11 is accomplished when valve V3 is opened in the same manner as interruption is accomplished in the case of thestructure shown in Figs. 2 and 7, i. e., fluid pressure-rotates the contact I02 and its nozzle block- I06. clockwise about the shaft pin I04 and also rotates the contact I03 and itsnozzleblock iI0'I. in the counterclockwise direction about the-shaft pin I05. The are is then blasted to extinction by the flow. of fluid between the contacts and through. the exhaust passages H2 and H3. After the arcis extinguished, the unit H9 is caused to move downwardly by the action of the fluid pressure from conduit [l0 provided'the latch I23 is moved out of engagement with back plate I00 by the action of fluid pressure ad mitted through valve V1. It will be obvious that suitable means would be provided for opening valve V1 an appropriate time after the opening ofvalve V3. I

For the purpose of preventing the accumulation. of substantial pressure below the unit 9' as the unit Jisj moved downwardly, .an opening I30 is provided which affords communication from within the chamber I3 to atmosphere so that air. ,within the chamber 13 and above'ith'e opening I30 will not be entrapped thereinthe unit II9 moves downwardly,,the passage III in block 91 "telescopically envelopes the conduit IIO. When the lower edge of unit II9 covers the opening I30, 'a certain amount of air will be entrapped between the lower surfac'e of the unit and the wall so as to afford a cushioned stop for theunit. When unit II9 reaches its low'ermost position, the latch I23 under'the action of the spring l24'engagesthe upper edge of the back wall I00 of the unit and efi'ectively locks the unit in the down position. In this way, anadequate isolating gap is established between the contacts I 02 and I03, obvious that pressure fluid'through valvevi' to operate piston I26 should be'shut-oif after the unit begins its downward travel and before the lowermost position thereof is-reached sothat the latch can perform its holding function after the unit reaches its lowermost position. It will also be obvious that it is the'action of gravity and of the pressure from valve V3 and conduit I I0 which causes downward movement of unit IIS aftersuch pressure has operated to open the interrupting contacts and to extinguish the arc. Valve Vishould be closed at an appropriate time which would insure that sufli'cient pressure fluid is 'availableto perform the isolating function without unduly prolonging thefluidi blast so as to avoid needless waste of pressure. fiuidi When a'cl'osing operation is performed, thev opening I30 must be closed. To this end, the opening I30 leading from: chamber 13' toiatmosphere is provided. with a normally open gate valve I3I which is biased to the open position by the spring I32. For closing valve I3 I, a piston I33 and its cooperating cylinder are provided. Fluid pressure for operating piston I33 is supplied from a source'not shown, through the valve V2 into conduit I34. Conduit I35 is connected with the valve V2 and is for the purpose of' admitting fluid pressure to the chamber 13 It n he so as to cause the unit to move upwardly to the closed position, the unit H9 acting as a piston. The'gate valve I3! is merely for the purpose of preventing the escape of fluid to atmosphere during closing operations of the interrupter. Of course, valve V1 would be opened just prior to or simultaneously with the opening of valve V2 so as to unlatch the unit. Valve V1 would be closed before the unit reaches its uppermost position so as to render the latch I23 capable of locking the unit in the upper position as shown in the drawings. It will also be obvious that valve V2 would be closed after the establishment of suflicient pressure within unit 13 to insure that a closing operation would be completed.

While the arrangement shown in Figs. 10 and 11 provides means for moving the single lower unit such as H9 only, it will be obvious to those skilled in the art that certain changes could be made so as to cause the upper unit comprising block 80, contact 102 and parts associated therewith to move upwardly simultaneously with the downward movement of unit H9. In this way, the isolating gap between the contacts would be made longer, and hence the voltage which the interrupter would withstand immediately follow ing an interrupting operation would be greater.

While I have shown and described particular embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from my invention in its broader aspects and I, therefore, intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

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

1. In an electric circuit interrupter of the fluid blast type, an arcing passage formed of stationary enclosing structure, a pair of relatively movable pivotally mounted long-wipe contacts disposed in said passage and separable in response to a. blast of fluid supplied to said passage, and nozzle means of insulating material disposed in said passage upstream of said contacts and operable in response to a blast of pressure fluid to said passage for automatically controlling the magnitude of the blast during a circuit interrupting operation, said nozzle means being effective to prevent blasting of said contacts until after a predetermined contact opening movement is accomplished.

2. In an electric circuit interrupter of the fluid blast type, an arcing passage formed of stationary enclosing structure, a pair of movable longwipe contacts in said passage, an inlet passage through which a blast of pressure fluid is supplied to said arcing passage for separating said contacts and for extinguishing the are drawn 'therebetween upon separation of said contacts, and nozzle means of insulating material movable with said contacts and having engaging surfaces upstream of said contacts for automatically increasing the blast of pressure fluid between said contacts after high velocity opening movement of said contacts is attained and for preventing blasting of said contacts until after a predetermined opening movement of said contacts.

3. In an electric circuit interrupter of the fluid blast type, an arcing passage formed of stationary enclosing structure, a pair of relatively movable long-wipe contacts in said passage, an inlet passage through which a blast of pressure fluid is supplied to said arcing passage for separating said contacts and for extinguishing the arc drawn therebetween upon separation of said contacts, and a nozzle block movable with one of said contacts and having a nozzle surface upstream of said contacts for automatically increasing the blast of pressure fluid between said contacts after high velocity contact opening movement is attained, said nozzle block being effective to increase the fluid blast before the arc is drawn between said contacts.

4. In an electric circuit interrupter of the fluid blast type, an arcing passage formed of stationary enclosing structure, a pair of movable longwipe contacts in said passage, an inlet passage through which a blast of pressure fluid is supplied to said arcing passage for separating said contacts and for extinguishing the are drawn therebetween upon separation of said contacts, and a nozzle block secured to each of said contacts and disposed in said passage, said blocks being normally in abutting relationship for closing said passage and being separable for automatically increasing the blast of pressure fluid supplied between said contacts, said nozzle blocks being configured to prevent the flow of fluid between said contacts until after said contacts attain a high speed opening movement.

5. In an electric circuit interrupter of the fluid blast type, an arcing passage formed of stationary enclosing structure, a pair of rotatable contacts in said passage, biasing means for normally holding said contacts in the closed circuit position, means for supplying a blast of pressure fluid to said passage to rotate said contacts to the open position and to blast the arc drawn therebetween to extinction, and a pair of nozzle blocks of insulating material normally in engagement with each other and rotatable with said contacts, said blocks being configured along their abutting surfaces so as to prevent blastin of said contacts until after a predetermined opening movement and thereafter to increase the blast of fluid between said contacts during a circuit interrupting operation.

6. In an electric circuit interrupter of. the gas blast type, an arcing passage formed of stationary enclosing structure, a pair of rotatable nozzle blocks of insulating material disposed in said passage, biasing means for normally holding said nozzle blocks in engagement with each other, a pair of interrupting contacts embedded within said nozzle blocks and having projecting portions thereof normally in engagement with each other, the surfaces of said nozzle blocks which are normally in engagement being upstream of said projecting portions of said contacts, an inlet passage through which a blast of gas is supplied to said arcing passage to cause rotation of said nozzle blocks and separation of said contacts and to blast the are drawn therebetween to extinction.

7. In an electric circuit interrupter of the gas blast type, an arcing passage formed of stationary enclosing structure, a pair of rotatable nozzle blocks of insulating material disposed in said passage, biasing means for normally holding said nozzle blocks in engagement with each other, a pair of interrupting contacts embedded within said nozzle blocks and having projecting portions thereof normally in engagement with each other, and an inlet passage through which a blast of gas is supplied to said passage to cause rotation of said nozzle blocks and separation of said contacts and to blast the arc drawn therebetween to extinction, the cooperating surfaces of saidnozzle blockswhich are normally'in one gagementbeing arcuate in shape so that the'flow of gas through said arcingpassage issubstantially prevented until after a predetermined relative movement of said contactsahasoccurred during a circuit interrupting operation.

8. In an electriccircuit interrupter or" the gas blast type, an arcing passage formed of stationary enclosing structure, a pair of rotatable nozzle blocks of insulating material disposedin said passage, biasing means for normally holding said nozzle blocks closely adjacent each other for closing said passage, a pairof interrupting contacts embedded within said nozzle blocks and having projecting portionsethereof normally engagement with each other, and an inlet pas-1 sage through which a blastzof gas is supplied tosaid arcing passage to cause rotation of'said nozzle blocks andseparation of said contacts and to blast the arc drawn therebetween to extinction, the upstream surfaces-of each of said nozzle blocks being configured to form a changing nozzle for controlling the flow of gas through said arcing passage only after a predetermined opening'movement of said contacts and saidadjacentsurfaces of said blocksbeing effective to prevent blasting of said contacts before said predetermined opening movement of said contacts.

9. In an electric circuit interrupter of the gas blast type, an arcing passage, a pair of rotatable nozzle blocks of insulating material having peripheries of generally circular configuration disposed in said passage, biasing means for normally holding said nozzle blocks closely adjacent one another for closing said passage, a pair of interrupting contacts embedded Within said noz zle blocks and having projecting portions thereof normally in engagement with each other, and an inlet passage through which a blast of gas is supplied to said passage to cause rotation of said nozzle blocks and separation of said contacts and to blast the are drawn therebetween to extinction, the upstream peripheral surfaces of each of said nozzle blocks being configured to form a nozzle for automatically increasing the flow of pressure gas through said arcing passage after a predetermined opening movement of said nozzle blocks and the downstream peripheral surfaces of said nozzle blocks being arcuate in shape to maintain a substantially unchanging configuration of said arcing passage in the region thereof downstream from said contacts.

10. In an electric circuit interrupter of the gas blast type, an arcing passage formed of stationary enclosing structure, a pair of rotatable nozzle blocks of insulating material disposed in said passage, biasing means for normally holding said nozzle blocks closely adjacent to each other, a pair of interrupting contacts embedded within said nozzle blocks and having projecting portions thereof normally in engagement with each other, for supplying a blast of gas to said passage to cause rotation of said nozzle blocks and separation of said contacts and to blast the are drawn therebetween to extinction, said nozzle blocks being configured to prevent blasting of said contacts until after predetermined opening movement of said contacts, a pair of exhaust passages leading from said arcing passages in divergent directions, and an arc divider of gas emitting insulating material disposed in said arcing passage intermediate said exhaust passages for diverting a portion of the blast through each of said exhaust passages and for supplying a secondary blast of gas to the are.

11. In an electric circuit interrupter of, the

fluid blasttype, an arcing passage, a pair of movable contacts in said passage, supporting means for said contacts, means for supplyinga blast of pressurefluid to said passage for separating said contacts and for extinguishing the are drawn therebetween upon separation of said contacts, a nozzle block movable with each of said contacts and operable, to increase automatically the blast of pressure fluid between said contacts during a circuit interrupting operation, and dashpot means for arresting the opening movement of said nozzle blocks including a recess'in said nozzle blocks'downstream from said contacts and a pocket. in said supporting means, said'recess andsaid pocket being operable-to en" trap fluidto cushion the opening movement of said nozzle block and said contacts.

l2'.--'A circuitinterrupting and isolating device comprising. an outer normally disposed iniengage-ment with each other within'said shell to define an interrupting chamher, said units being relatively movable with respect to'each other in a' direction longitudinal with respect to said shell and the complementary surfaces of said units being configured to form a substantially fluid tight junction therebetween, a contact member pivotally supported on each unit, a nozzle block movable with each contact member, said nozzle blocks being in engagement with each other during the initial opening movemerit of said contacts for preventing blasting of said contacts until after predetermined opening movement of said contacts, means for biasing said contact members toward each other, and means for supplying a blast of fluid to the interrupting chamber to separate said contacts and extinguish the are drawn therebetween and for separating said units following an interrupting operation.

13. A circuit interrupting and isolating device comprising an outer weatherproof insulating shell, a pair of complementary insulating units normally disposed in engagement with each other Within said shell to define an interrupting chamber, said units being relatively movable with respect to each other in a direction longitudinal with respect to said shell, and the complementary surfaces of said units being configured to form a substantially fluid tight junction therebetween, a contact member supported by each unit, means for biasing said contacts toward each other, means for supplying a blast of fluid to the interrupting chamber to separate said contacts and extinguish the are drawn therebetween and for separating said units following an interrupting operation, and latching means for releasably holding said units in engagement until the arc is extinguished during a circuit opening operation and for holding said units out of engagement upon completion of a circuit isolating operation.

14. An electric circuit interrupter comprising an interrupting chamber, an exhaust chamber disposed adjacent said interrupting chamber and in communication therewith, a pair of relatively movable contacts disposed in said interrupting chamber, each of said contacts being removable from said interrupting chamber, means for supplying a blast of pressure fluid to said interrupting chamber to separate said contacts and extinguish the are drawn therebetween, another chamber adjacent said interrupting and exhaust chambers for receiving one of said contacts upon weatherproof insulating; shell, a pair of complementary insulating unitsremoval thereof from said interrupting chamber, and thrust means disposed in said another chamber for releasably securing said one contact in position in said interrupting chamber, said last mentioned means being constructed of conducting material and being in series with said contacts when arranged to secure said one contact in position within said interrupting chamber.

15. An electric circuit interrupter comprising an interrupting chamber, an exhaust chamber disposed adjacent said interrupting chamber and in communication therewith, a. pair of relatively movable contacts disposed in said interrupting chamber, each of said contacts being removable from said interrupting chamber, means for supplying a blast of pressure fluid to said interrupting chamber to separate said contacts and extinguish the arc drawn therebetween, another chamber adjacent said interrupting and exhaust chambers for receiving one of said contacts upon 20 circuit breaker, said holding means being effective normally to secure said one contact in position within said interrupting passage and being arranged so that said one contact may be removed through said another chamber and said door upon release of said holding means.

WILLIAM E. PAUL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,901,679 Uebermuth Mar. 14, 1933 1,982,355 Ruppel Nov. 27, 1934 2,192,772 MacNeill Mar. 5, 1940 2,288,324 Prince June 30, 1942 2,445,529 Leeds July 20, 1948 2,477,810 Leeds et a1 Aug. 2, 1949 2,481,996 Grunewald et al. Sept. 13, 1949 2,551,772 Thibaudat May 8, 1951 FOREIGN PATENTS Number Country Date 316,952 Great Britain Sept. 11, 1930