US2297818A - Circuit interrupter - Google Patents

Description

Oct. 6, 1942'. R. c. VAN SICKLE 2,297,818

CIRCUIT INTERRUPTER Filed May 21, 1941 Fig! WITNESSES: INVENTOR Patented Oct. 6, 1942 UNITED STATES "PATENT OFF-ICE Boswell C. Van Sickle, Wilklnsburg, Pm, ma

to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa'., a corporation of Pennsyl Application May 21, 1941, was... 394,401

' 15 Claims. (01. 200-148) This invention relates to improvements in circuit interrupters, and more particularly to circuit interrupters of the fluid blast type wherein a compressed gas as air, for example, is directed into the arc stream to bring about arc extinction.

Various forms of fluid blast circuit interrupters have been heretofore proposed utilizing single and multiple blasts of fluid directed either transversely or longitudinally of the arc. The circuit interrupter capacities of these prior devices, however, are dependent upon the use of relatively high blast pressures. When a compressed gas of high pressure is used, difliculties in compression, storage and control of the gas supply are encountered. Although somewhat lower gas pressures have been made possible by the use of auxiliary resistors and are splitting devices, such expedients introduce complications and consequently greatly add to the initial cost and also to the cost of maintenance.

It is well known that a gaseous fluid being ejected from a nozzle attains a velocity which is a function of the square root of the pressure acting thereon, but which has a limiting velocity approximating that of sound. In one aspect of my invention I propose to subject a portion of the arc stream to extinguishing action equivalent to that which would be produced by the use of a single jet having twice the limiting velocity now attainable. I do this by subjecting two adjacent portions of the arc stream to two cooperating jets of arc extinguishing fluid flowing generally in opposite directions. Consequently, the thin slab of the arc stream intermediate said two portions has its upper surface swept by one jet, and its lower surface swept generally in the opposite direction by the other cooperating jet. The eflect of this action is the equivalent of the action produced by the use of a single Jet having twice the velocity now attainable in a single Jet acting upon a single portion of the arc stream.

The principal object of my invention is to provide a circuit interrupter of the fluid blast type that is simple in design and capable of interrupting high power with a relatively low blast pressure.

My invention contemplates obtaining improved arc extinction by subjecting an intermediate portion of a length of are to the action of opposing blasts of arc extinguishing fluid.

More specifically, I propose directing the opposed blasts generally transversely of the arc so that the arc section in the path of said blasts is subjected to the relative velocity between said blasts which, in eflect, isequivalent to a. single blast of twice the velocity of either of the two opposed blasts but which is thus obtained with only the same pressure.

Applicant is aware that opposed fluid blasts which envelope the contact structure and the arc therebetween have been heretofore proposed. This arrangement, however, does not obviate the use of high blast pressures, in thatthe opposing jets or streams directly impinge on each other and thereby form dead spaces in the arc stream which abound in ionized particles, and consequently make arc extinction diflicult. Arc extinction is further made dimcult in that the jets of fluid streaming past the opposed contacts carry the metallic vapor emanating from the contacts into the arc path.

A further object of the instant invention is to improve the arc extinguishing action of a fluid blast interrupter by the provision of means for directing opposing blasts of fluid upon a section of are removed from the terminal ends of the arc and in a region where the density of metallic vapor from the contacts is a minimum.

' ing carried into the arc path.

Other objects and advantages will appear in the following description when taken in connection with the accompanying drawing, in which:

Figure 1 is a side view partially in section showing a circuit interrupter embodying my invention; and

Fig. 2 is an exploded sectional view showing details of the arc chamber construction of the interrupter illustrated in Fig. 1.

Referring to the drawing, the reference numeral 3 designates a supporting framework which carries a tubular insulator 5. Mounted upon the insulator 5 is a split metallic casingwhich, in turn, carries an insulator 8. The insulator 9 has an elongated passage ii therethrough which serves as an arcing chamber. The upperend of the insulator 9 is provided with a metallic terminal member [3 which has a flared exhaust projection 15 thereon. The terminal member I3 is provided with a stationary contact assembly ll extending downwardly in an enlarged portion 19 of the arc passage H.

The arc passage l l is also enlarged at its lower end and registers with an opening 2| in the upper Wall of casing I so as to place the passage in communication with the inside of the casing I. Operative through the casing 1 and the passage II and also coacting with the stationary contact assembly I1 is a movable contact 23. The lower end of the movable contact 23 is operatively coupled to a straight line operating linkage generally indicated at 25. I

The linkage 25 may beactuated to the closed circuit position by-coinpressed air mechanism comprising. a cylinder 21 having a piston 29 therein, which piston is coupled by a connecting rod 3| to the linkage 25. Compressed air for actuating the piston 29: may be obtained from the storage tank 33 carried by the supporting frame 3 and may be controlled by an-electromagnetical- 1y actuated valve 35. Movement of the contact operating linkage 25 to the open circuit position be efiected by the energization of a suitable trip When the interrupter is in the closed circuit position, as shown in Fig. 1, an electrical circuit is established therethrough from the upper terminal member l3, through the stationary contact I1, the movable contact 23, sliding contacts 24 to the metallic casing I. External circuit connections to the interrupter are made to terminals 43 and 45 secured, respectively, to the terminal member 13 and the casing I. Upon the occurrence of an overload in the circuit in which the interrupter is connected, trip coil 4| will be energized in theusual and well-known manner so as to release the latch 39 allowing the spring 31 to actuate the linkage 25 and the movable contact 23 to the open circuit position. An arc will thus be drawn between the stationary contact assembly I 1 and the moving contact 23 within the passage I l.

Extinction of the arc is accomplished by subjecting a portion of the are intermediate the.

length of the passage H to the action of opposed blasts of gas. These blasts may be created by compressed air stored within the tank 33 convalve 41. Compressed air from the valve 41 is conducted by an insulating conduit 49 through the metallic casing 1'. r The upper portion of the conduit is divided into two branches 5| and 53 which terminate in the upper wall of the casing 1, as shown.

A passage'55 formed within the insulator 9 extends from the branchv 5| to a point intermediate the ends of the passage H. The passage 55 has a final length thereof which terminates in a nozzle56 arranged with its longitudinal axis forming an acute angle with respect to the longitudinal axis of the arc passage II. The insulator 9 has a second passage 51 formed therein which leads from the branch conduit 53 and also trolled by an electromagnetically actuated blast has a nozzle portion 58 terminating intermediate the ends of the are passage H. The nozzle portion 58 of the passage 51 is generally parallel with and closely adjacent to the nozzle portion 56 of the passage .55. In order to facilitate the forming of passages and 51 in the insulator 9, I propose constructing the insulator 9 of two I parts as more clearly shown in Fig. 2. The lower portion of the insulator 9 has a generally cylindrical cavity 59 formed therein. The passages 55 and 51 may then in part be formed by either machining or otherwise providing channels in the opposite side walls, as shown.

The cylindrical cavity 59 is filled with a filling member 6| whose shape is complementary to that of the cavity 59 and is provided with a central opening which constitutes the lower portion of the arc passage 1!. A diagonal bore 63 through the upper left-hand portion of the filling member 6| completes the passage 51. Thus when the filling member BI is positioned within the cavity 59, the outer walls of the filling member 6! complete, in general, the blast conducting passages 55 and 51.

Upon release of the latch 39 and movement of the movable contact 23 to the open circuit position, suitablev control mechanism is provided which is also well-known in the art for actuating the electromagnetically controlled blast valve 61 so as to admit a blast of gas under pressure from the tank 33 through the conduit 49, the branch conduits 5| and 53, and through the passages 55 and 51.

The nozzles 56 and 58 being positioned on opposite sides of the are drawn between the contacts I1 and 23, subject an intermediate portion of the arc to the action of opposed blasts of arc extinguishing gas. These blastsimpinge violently upon the arc stream creating a high degree of turbulence so as to bring about diffusion of the ionized particles and subsequent extinction of the arc. The fact that the two jets or blasts of arc extinguishing gas are generally opposed to each other and side by side has the effect of subjecting a portion of the arc to a blast of twice the velocity of a single blast. Since the velocity of the gas is a function of the pressure of the gas supply, it follows that the two generally opposed velocities create an efiect depending upon the relative velocity of the gas between the two jets which would correspond to twice the velocity of either jet, or a much higher gas pressure on a single jet.

The nozzles 56 and 58 may be arranged so that they at least partially impinge upon each other within the arc path, so that the boundary between the two jets is in a highly turbulent stage. The nozzles 55 and 58 may also be so designed and arranged that they produce two streams or jets having a boundary therebetween that is substantially sharply defined, in which case a very thin section of arc would be subjected to the shearing stresses of the two opposed blasts of arc extinguishing fluid. In either case, conditions are set up within the arc stream that are favorable to are extinction.

'Inasmuch as the jets of arc extinguishing gas are directed against the are intermediate its ends, the point of interruption takes place remote from either-the stationary contact l1 or the top portion of movable contact 23. Arc extinction, therefore, is less diflicult in that it takes place in a region where the density of metallic vapor from the contacts is at a minimum. Furthermore, the particular arrangement makes provision for carrying the metallic vapor from the contacts l1 and 23 out of the arc passage ll gas and the products of arcing from the central I region of the passage ll both upwardly through the exhaust projection l5, and also downwardly through the opening 2| into the casing 1 where it may exhaust to atmosphere through an opening II. The fact that are extinction is caused to take place remote from the contacts has a further advantage, in that it decreases the erosion of the contact surfaces. It has been established that a high degree of turbulence such as is produced by directing a blast of arc extinguishing gas directly upon the terminal of an arc causes a higher degree of contact erosion.

The word fluid," as herein used in the speciflcation and in the following claims, is used in its broadest sense and is intended to include gases, vapors and liquids.

Although I have shown and described a peciflc circuit interrupting structure, it is to be understood that the same is for the purpose of ustration and that changes and modiflcatio may be made by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

1. In a circuit interrupter of the fluid blast type, separable contact means for establishing an arc, a pair of cooperating nozzles disposed adjacent the intermediate portion of said arc, the two nozzles of said pair being positioned substantially on opposite sides of said arc and axially offset with respect to each other so that the two jets of fluid from said pair of nozzles subject a portion of the arc therebetween to the shearing stresses created by said pair of jets, said pair of jets being directed into said arc path at an inclined angle with respect to the longitudinal axis of said arc.

2. In a circuit interrupter of the fluid blast type, separable contact means for establishing an arc, a pair of cooperating spouts disposed adjacent the intermediate portion of said arc, the two spouts of said pair being positioned substantially on opposite sides of said arc and axially oifset with respect to each other so that the two jets of arc extinguishing fluid from said pair charging substantially longitudinally of said arc through said venting means.

5. In a circuit interrupter of the fluid blast type, means at least partially of insulating material deflning an elongated arc chamber, separable contact means for establishing an arc within said elongated chamber, said means of insulating material having at least two-axially offset passages therethrough for conducting arc extinguishing fluid into said chamber, and means for conducting arc extinguishing fluid under pressure into said passages, said passages being arranged to direct axially offset opposedstreams of are extinguishing fluid into a portion intermediate the length ofsaid arc and at an inclined angle thereto.

6. In a circuit interrupter of the fluid blast type, means at least partially of insulating material deflning an elongated arc chamber, separable contact means for establishing an arc within said said pair of spouts will at least in part impinge elongated chamber, said means of insulating material having at least two axially oiIset and substantially parallel passages therethrough for conducting arc extinguishing fluid into said elongatedchamber, means for conducting are extinguishing fluid under pressure into said passages, said passages being arranged to direct two axially offset opposed streams of arc extinguishing fluid into a portion intermediate the ends of said arc and at an acute angle thereto, and vent means for said arc chamber disposed adjacent said separable contact means at the ends of said chamber to cause said arc extinguishing fluid to sweep the products of arcing from the arc path and out of the vent means at the ends of are directed into the arc path to establish a highly turbulent region for deionizing the arc stream and to subject a portion of said are to the shearing stresses caused by said pair of jets, said pair of jets discharging substantially longitudinally of said arc.

3. In a circuitinterrupter oi the fluid blast type, separable contact means for establishing an are, a pair of cooperating outlets disposed at an inclined angle with respect to the longitudinal axis of said are and positioned adjacent an intermediate portion thereof, the two outlets of said pair being positioned substantially diametrically on opposite sides of said arc and substantially parallel to one another, said two outlets being axially offset with respect to each other so that the two jets of fluid from said two outlets subject a portion of said are to the shearing stresses created by said pair of jets, said pair of jets being substantially parallel to one another and at an inclined angle with respect to the longitudinal axis of said arc.

4. In a circuit interrupter of the fluid blast type, means at least partially of insulating material defining an elongated arc chamber, means for establishing an are within said elongated arc chamber, means directing at least two axially offset opposed streams of arc extinguishing fluid into an intermediate portion of said arc, and venting means comprising an outlet adjacent each end of said elongated arc chamber for the escape of arc extinguishing fluid and the products of arcing, said two axially ofiset streams diesaid chamber.

7. In a circuit interrupter, means at least partially of insulating material defining an elongated arc chamber open at its ends, contact means separable within said chamber to establish an arc therein, and two fluid conducting passages leading into said arc chamber from opposite sides thereof, said two passages being arranged to direct two cooperating jets of arc extinguishing fluid which are axially offset with respect to each other against an intermediate section of said are and at an acute angle thereto, said jets breaking up the continuity of the arc stream and causing the products of arcing to exhaust through the ends of said arc chamber, said two cooperating jets flowing in substantially opposite directions.

8. In a circuit interrupter, means at least par tially of insulating material defining an elongated arc chamber open at its ends, contact means separable within said chamber to establish an arc therealong, means providing a fluid conducting passage leading into said are chamber, said passage terminating with a nozzle, said nozzle being arranged to direct a jet of are extinguishing fluid against said are intermediate its ends and at an acute angle with respect to the longitudinal axis thereof, said means providing a second fluid conducting passage leading into said arc chamber, said second passage terminating with a second nozzle, said two nozzles being at least partially axially ofiset, said second nozzle being arranged to direct a second jet of are extinguishing fluid against an intermediate portion of said are in an opposite direction but generally parallel to the flow of fluid in said first jet, said two jets cooperating to cause a high rate of dif- ,9. In a circuit interrupter of the fluid blast type, separable contact means for establishing an arc, a pair of cooperating spouts disposed at an inclined angle with respect to said are and adjacent. the intermediate portion thereof, said pair of spouts also being positioned substantially diametrically on opposite sides of said are and at least partially axially offset with respect to each other, the two blasts of fluid from said pair of spouts being directed at an inclined angle with respect to the longitudinal axis of said are and im'pinging at least in part upon each other in the arc path to efiect the extinction of said are.

10. In a circuit interrupter of the fluid blast type, separable contact means for establishing an are, a pair of cooperating nozzles disposed adjacent the intermediate portion of said arc, the two nozzles of said pair being positioned substantially on opposite sides of said are and at least partially axially offset with respect to each other so that the two jets of fluid from said pair of nozzles will at least in part impinge upon each other in the arc path to effect the extinction of said are, said two jets discharging substantially longitudinally of said are to prevent metallic particles from said contact means entering the interruption zone.

11. In a circuit interrupter of the fluid blast type, separable contact means for establishing an are, a pair of cooperating spouts disposed adjacent the intermediate portion of said are, said pair of spouts being positioned at an inclined angle with respect to the longitudinal axis of said are and substantially parallel to one another, said pair of spouts being disposed substantially diametrically on opposite sides of said are and at least partially axially ofiset with respect to one another so that the two jets of fluid issuing from said pair of spouts will at least in part impinge upon each other in the arc path, said pair of jets of fluid being directed substantially parallel to one another and at an inclined angle with respect to the longitudinal axis of said are.

12. In a circuit interrupter of the fluid blast type, separable contact means for establishing an arc, a pair of cooperating outlets disposed adjacent the intermediate portion of said are and substantially parallel to one another, said pair of outlets being positioned on opposite sides of said are and axially oiiset with respect to each other so that the two jets of fluid from said pair of outlets subject a portion of said arc to the shearing stresses created by said pair of jets, said pair of jets being substantially parallel to one another and discharging generally longitudinally of said are to sweep ionized products of decomposition toward said contact means.

13. In a circuit interrupter of the fluid blast type, separable contact means for establishing an are, a pair of cooperating nozzles disposed adjacent the intermediate portion of said are and positioned substantially diametrically on opposite sides thereof, said pair of nozzles being substantially parallel to one another and also at least partially axially oifset with respect to one another so that the two jets of fluid from said pair of nozzles will at least in part impinge upon each other in the arc path to effect the extinction of said are, said pair of jets being substantially parallel to one another and discharging substantially longitudinally of said are in the direction of said contact means to prevent ion- 14. In a circuit interrupter of the gas blast type, a cylindrically-shaped longitudinal arcing chamber composed at least in part of insulating material, stationary contact means disposed at one end of said chamber, venting means disposed adjacent said stationary contact means, a second venting means disposed adjacent the other end of said chamber, a movable cooperating rod-shaped contact movable longitudinally within said chamber to establish an arc axially within said chamber, a pair of gas, conducting passages formed within the lateral wall of said chamber, said pair ofpassages terminating in a pair of nozzles, said pair of nozzles being disposed substantially parallel to one another and positioned substantially on opposite sides of said are, said pair of nozzles also being disposed intermediate the ends of said are and making an inclined angle with respect tosaid are, means for causing gas flow through said pair of nozzles upon the establishment of said are, said pair of nozzles being at least partially axially offset with respect to each other so that the two jets of gas issuing therefrom will subject an intermediate portion of said are to the shearing stresses created by said, pair of jets, said pair of jets being substantially parallel to one another and at an inclined angle with respect to the longitudinal axis of said are, said pair of jets dis charging in substantially opposite directions substantially longitudinally of said are and through said two venting means at opposite ends of said chamber to prevent ionized particles emitted from said stationary contact means and the end of said movable contact from entering the zone ofinterruption.

15. In a circuit inter pter of the gas blast type, a cylindrically-sha d longitudinal arcing chamber at least partly composed of insulating material, stationary contact means disposed at one end of said chamber, venting means disposed adjacent said stationary contact means, a second venting means disposed adjacent the other end of said chamber, a movable cooperating rodshaped contact movable longitudinally within said chamber to establish an arc axially therein, a pair of gas conducting passages formed within the lateral wall of said chamber, said pair of passages terminating in a pair of nozzles, said pair of nozzles being positioned substantially parallel to one another and disposed substantially on opposite sides of said are, said pair of nozzles also being disposed intermediate the ends of said are and making an inclined angle with respect to the longitudinal axis of said are, means for causing gas flow through said pair of nozzles upon the establishment of said are, said pair of nozzles being at least partially axially offset with respect to each other so that the two jets of gas issuing therefrom will-at least in part impinge upon each other in the arc path, said pair of jets being substantially parallel to one another and at an inclined angle with respect to the longitudinal axis of said arc, said pair of jets creating deionization conditions in the arc path to extinguish said arc, said pair of jets discharging in substantially opposite directions substantially longitudinally of said are and through said two venting means disposed at the opposite ends of said chamber to prevent ionized particles emitted from said stationary contact means and the end of said movable rod-shaped contact from entering the zone of interruption.

ROSWELL C. VAN SICKLE.

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