US3670126A - Compressed-gas circuit interrupter having a pair of rapid transfer insulating nozzles - Google Patents

Abstract

A gas-blast type of circuit breaker is provided having a pair of separable contacts with a pair of contractable insulating nozzles disposed closely adjacent the point of separation of the separable contacts. In one embodiment of the invention, there is provided a pair of tubular separable contacts, through which the gas exhausts, and a pair of spaced contractable insulating nozzles are provided to locate the arc quickly axially and to control the gas-flow conditions.

Description

United States Patent Roidt [54] COMPRESSED-GAS CIRCUIT RINTERRUPTER HAVING A PAIR OF RAPID TRANSFER INSULATING NOZZLES [72] Inventor: Robert M. Roidt, Pittsburgh, Pa.

[73] Assignee: Westinghouse Electric Corporation, Pittsburgh, Pa.

[22] Filed: July 1,1969

[2!] Appl.No.: 838,157

[52] us. c1. zooms 11, 200/148 B [51] mm. ..l-l01h33/54 [58] Field ofSearch ..'.200/148,148.2,148B,149,

[561 References Cited UNITED STATES PATENTS 3,297,848 1/1969 Picardetal, "zoo/149x.

CLOSED POSITION June 13, 1972 FOREIGN PATENTS OR APPLICATIONS 1,271,241 6/ l 968 Germany ..200/l 48 BV 36,453 4/1965 Germany ..200/ l 48 l8l,356 3/1936 Switzerland ,.200/l48 Primary Eraminer-Robert S. Macon Attorney-A. T. Stratton, Clement L. McHale and Willard R. Crout 57 ABSTRACT A gas-blast type of circuit breaker is provided having a pair of separable contacts with a pair of contractable insulating nozzles disposed closely adjacent the point of separation of the separable contacts. In one embodiment of the invention, there is provided a pair of tubular separable contacts, through which thegas exhausts, and a pair of spaced contractable insulating I noules are provided to locate the are quickly axially and to control the gas-flow conditions.

5 Claims, 8 Drawing Figures PATENTEDJUH 13 1972 SHEET 10F 4 FIG. I.

INVENTOR Robert M. Roidf WITNESSES ATTORNEY P'A'TE'N'TEDJUN 13 1972 SHEET 2 OF 4 LOW PRESSURE HIGH PRESSURE GAS LOW PRESSURE GAS P'ATENTEDJUM 13 m2 SHEET 3 OF 4 zoEmom Qwmod QM PATENTEDJUH 1 3 I517? SHEEI U 0F 4' EXTENDED CONTRACTED COMPRESSED-GAS CIRCUIT INTERRUPTER HAVING A PAIR OF RAPID TRANSFER INSULATING NOZZLES CROSS-REFERENCES TO RELATED APPLICATIONS BACKGROUND OF THE INVENTION In compressed-gas circuit breakers of the type involving a pair of separable tubular relatively movable contacts, it has been customary to provide a high-pressure gas region exteriorly of the separable contacts, and upon opening, or separation thereof, the high-pressure gas flow extends radially inwardly and may exhaust through one or both of the separable contacts. US. Pat. application Ser. No. 759,992, filed Sept. 16, 1968 by Lee E. Berkebile illustrates such a construction. In the open-circuit position of the interrupter, as set forth in the aforesaid Berkebile circuit breaker construction, highpressure gas may exist in the region between both fully open separated contacts. As utilized in the aforesaid patent application, downstream secondary blast valves may be employed to halt the exhausting of high-pressure gas flow through the separated contacts in the fully open-circuit position of the interrupter.

SUMMARY OF THE INVENTION In accordance with an embodiment of the present invention, there is provided a pair of separable contacts in a highpressure gaseous atmosphere with a pair of contractable insulating spaced nozzles disposed adjacent the point of contact separation. Preferably, the separable main contacts themselves provide a primary blast valve, so that upon separation of the contacts, there may occur a radial inward flow of highpressure gas into at least one of the separable contacts. Controlling the flow of exhausting gas through said one contact, or in the particular arrangement involving both separable contacts, is one or more secondary blast valves, which are disposed downstream of the gas flow. A pair of contractable insulating spaced nozzles move radially inwardly upon being released by opening movement of the movable contact, and these contractable insulating nozzles serve to force the established arc axially along the center-line of the movable vented separable contacts to increase the efficiency of are ex- I tinction.

The mechanical arrangement is such that the downstream secondary blast valves remain open for a predetermined time to assure an interruption of the are established between the separable'contacts. At a point in time, where assurance is had that the arc has been extinguished, the mechanical arrangement is such that the secondary blast valves are closed, thereby halting any further exhausting of the high-pressure gas through the separable contacts.

During a closing operation of the circuit breaker, the primary blast valve, disposed immediately adjacent the point of abutment of the separable contacts, insures a sealing condition at this point, and the mechanical arrangement during such a closing operation is such as to open the one or more secondary blast valves, to thereby permit a lowering of the pressure communicating with the region interiorly of the separable contacts.

Accordingly, a general object of the present invention is to provide a high-speed compressed-gas circuit interrupter utilizing a pair of contractable nozzles for increasing the efficiency of arc extinction.

Another object of the present invention is the provision of improved means for axially locating the arc established in a compressed-gas circuit interrupter of the type in which a radial inward gaseous flow occurs.

Still a further object of the present invention is the provision of an improved compressed-gas circuit interrupter of the type utilizing a primary blast valve, one or more secondary blast valves, and a pair of contractable insulating nozzles, which are collapsed during the opening operation to assure an accurate centering of the arc axially along the center-line of the contact structure.

Further objects and advantages will readily become apparent upon reading the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end elevational view of a compressed-gas circuit interrupter embodying the principles of the present invention;

FIG. 2 illustrates a vertical sectional view taken through the interrupting chamber of the circuit interrupter of FIG. 1, the contact structure being illustrated in the closed-circuit position;

FIG. 3 is an enlarged vertical sectional view illustrating the contact structure in the cIosed-circuit position thereof;

FIG. 4 is a view similar to FIG. 3, but illustrating the disposition of the several parts during the initial portion of the opening operation;

FIG. 5 is a view similar to FIGS. 3 and 4, but illustrating the disposition of the parts at a later point in time during the opening operation;

FIG. 6 is a fragmentary perspective view of the contractable insulating nozzle construction; 1

FIG. 7 is a view similar to that of FIG. 6, but illustrating the contractable nozzle construction in the contracted position thereof; and,

FIG. 8 is a vertical sectional view taken through one of the two contractable noule arrangements.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 designates generally a compressed-gas circuit interrupter. As viewed in FIG. I, it will be noted that there is provided an end view of a three-phase com pressed-gas circuit interrupter, each phase unit, such as phase unit A, comprising a leftwardly slanting arc-extinguishing assemblage, generally designated by the reference numeral 2, and a right-hand slanted tenninal-bushing structure, generally designated by the reference numeral 3.

The lower end of the arc-extinguishing assemblage 2 is electrically connected by a curved electrical conductor 4 more clearly illustrated in FIG. 2 of the drawings. Accordingly, it will be apparent that there is provided a generally U-shaped circuit-breaker structure 1 with one leg of the U constituting the arc-extinguishing assemblage 2, whereas the righthand leg of the U" constitutes generally the terminal-bushing structure 3. Lead connections L L, are attached to the upper extremities of the generally U-shaped circuit interrupter l, as indicated in FIG. 1 of the drawings.

The compressed gas circuit interrupter l of the present invention is generally of the dual-pressure type in which highpressure gas 5 is stored in a tank, not shown, and is disposed immediately adjacent the separable contact structure 7 in the region designated by the reference numeral 8 in FIGS. 3-5 of the drawings. Such region 8 is also illustrated in FIG. 2 of the drawings, and designated by the same reference numeral. The region 9, rearwardly of both contact structures 10, 11, is at relatively low pressure. These regions are designated by the reference numeral 9, and are pneumatically interconnected by at least one interconnecting conduit designated by the reference numeral 12 in FIG. 2 of the drawings.

Generally, the manner of operation of the circuit interrupter l, illustrated in FIGS. 1-3, is the actuation of tripping valves, generally designated by the reference numeral 14 in FIG. 2 of the drawings. The actuation of such tripping valves 14 through a linkage l5, hereinafter described, causes the entrance of high-pressure gas 5 below a piston structures, one of which is provided at the upper end of each of the three arcextinguishing assemblages 2.

The upward movement of the piston structure causes a corresponding upward opening motion of a mechanical linkage,

.which, in turn, causes upward movement of a generally ladder-type operating rod linkage, which inter-connectsthe two secondary blast valves 23a, 23b associated with the arcextinguishing unit 25 of the assemblage 2. In more detail, referring .to FIGS. 3-5 of the drawings, it will be noted that there is a pair of separable contacts 10, 11 having a primary blast valve structure 27, and a pair of secondary blast- valve structures 23a, 23b. The secondary blast- valve structures 23a, 23b are mechanically interconnected by the ladder-shaped operating linkage, and are simultaneously actuated.

Accordingly, to effect the opening operation of the compressed-gas circuit interrupter l of the present invention, the tripping valves 14 in the three phase units are simultaneously opened to cause the entrance of high-pressure gas upwardly through the conduits, and against the lower surfaces of the piston structures. This causes upward opening movement of the piston structures and corresponding upward movement of the ladder linkage arrangements, and, in addition, causes upward movement of an operating rod 30 mechanically connected to the movable contact structure 10. Reference may be directed to the operating rod 30 of FIG. 3. I

Upward opening movement of the ladder-shaped linkage causes opening of the movable contact away from the primaryblast-valve seat 32 and separationithereof from the stationary contact fingers 34, which make engagement therewith in the closed-circuit position of the device, as illustrated in FIG. 3 of the drawings.

During the initial portion of the opening operation, both secondary blast valves 23a, 23b are opened, and the high-pressure gas in the region 8 flows radially inwardly, and through both separable tubular contacts 10, ll exhausting therethrough into the regions 9 downstream of the separable contacts 10, 11. This exhausting flow is controlled by the secondary blast valves, 23a, 23b which areoperated in unison.

With reference beingparticularly directed to FIGS. 3-5 of the drawings, it will be observed that the are 38, which is drawn between the contact fingers 34 and the extremity 10a of the moving tubular contact 10, is quickly transferred to the inner stationary tubular arcing contact 40 being subjected to a flow of gas, as indicated by the arrows 41 in FIGS. 4 and 5 of the drawings. During this time, both primary and secondary blast valves 27, 23a, 23b are opened. When the are 38 has been extinguished, it is desirable to halt the further consumption of high-pressure gas, and to effect this end closure of the secondary blast valves 23a,-23b is desirable. This closing motion of the secondary blast valves is achieved by a flange portion 10b secured to the movable contact 10, which compresses a compression spring 43 and following the overcoming of friction at the seal 44,.the secondary movable blast valve 23a is closed up against its seat 45, thereby halting the further flow of compressed gas. The right-hand secondary blast valve 23b, as illustrated in FIGS. 3-5 of the drawings, is mechanically connected to the ladder-shaped operating linkage, and therefore moves simultaneously with the left-hand secondary blast valve 230. In other words, both the moving contact 10 and the flange portion l0b thereof, and also the operating rod 46, together with its actuator portion 46a, causes compression of the compression spring 43a and corresponding closure of the right-hand secondary blast valve 23b against its seat 45a. The breaker is now in the open-circuit position with the primary blast valve opened, and both secondary blast valves 23a, 23b closed.

During the closing operation, the high-pressure gas is exhausted from the lower surface of the piston structures, and the high-pressure gas which is constantly present above the piston structures causes the downward closing motion thereof. This is communicated through the ladder-shaped linkage and also through the operating rod 30 connected to the movable contact 10. As. a result, the moving contact 10 moves.

downwardly, as viewed in FIG. 1 of the drawings, and the operating rod, being connected to the ladder-shaped linkage,

also moves downwardly to thereby effect opening of the secondary blast valves. The circuit breaker is now in the closed-circuit position.

To enable the circuit breaker l to carry considerable current, there-is provided the two pairs of stationary contact fingers 34, 48, each of which is supported by its contact holder 340 or 48a. The contact holders are, as readily apparent in FIG. 2, bolted to the plate portions 50, 51 constituting the ends of the low-pressure regions rearwardly of the stationary and movable contact structures 10, 11, reference being had to FIG. 3 in this connection.

his a distinct purpose of the present invention to provide a new type of circuit-breaker configuration which will allow retention of the important characteristics associated with finger nozzle contacts, as set forth in US. Pat. application filed Jan. 8, 1968, Ser. No. 696,415 by Stan Milianowicz. Basically, the device comprises two spring-loaded sectioned contractable nozdes 70, 71, which slide into place behind separating contact cylinders to force an initially axial arc 38, and eliminate the need for flow-forced transfer. A perspective view of the contractable nozzle 70 is illustrated in FIGS. 6 and 7 of the drawing, and the sequence of the interrupting procedure is illustrated in FIGS. 3-5 of the drawings.

The noule 70, illustrated in FIG. 7, comprises four sections, 70a, 70b, 70c, 70d but for certain types of interrupteis, perhaps three might be found preferable. The nozzle sections are designed so that the moving contact cylinder 10 forces them apart during contact reclosure. The distance the nozzle sections 70, 71 move would not be very great since their primary function is simply to force the are 38 toward the centerline and prevent arcing upstream of the minimum nonle area. They also force the are 38 away from the steady state operation contact point.

The fundamental intention behind the present invention is the step toward obtaining the maximum possible interrupting capability for a given nozzle area and operating pressure.

In more detail, it will be noted, with reference to FIGS. 6 and 7 of the drawings that the nozzle sections are captive within an insulating nozzle holder 74 having end-plate portions 74a, and axially positioned bosses 78, which limit the guiding motion of the noule sections 70a, 70b,70c, 70d. FIG. 7 illustrates the nozzle 70 in the collapsed or retracted position, whereas FIG. 6 illustrates the nozzle 70 in its expanded condition, which is the state as set forth in FIG. 30f the drawings. FIG. 8 is a sectioned view taken through the nozzle 70 ofFIG. 7, taken along the line IX-IX of FIG. 7. I

For the purpose of biasing the nozzle portions 70a, 70b, 70c, 70d radially inwardly, leaf springs may be provided as illustrated in FIG. 7 of the drawings.

It will be noted that the first contractable insulating nozzle structure 71 additionally delays application of the inward blast of gas upon the arc 38 during the initial establishment thereof. This is desirable because the arc 38 cannot be extinguished prior to its attaining a predetermined length as well known by those skilled in the art. Consequently, this additional action on the part of the first nozzle structure 71 minimizes the generation of arcing energy at a time when are interruption is not possible, and avoids voltage surges on the connected line.

The nozzle sections would preferably be made from a suitable arc-resistant dielectric material, such as polytetrofluoroethylene and sold under the tradename Teflon.

From the foregoing description it will be apparent that there has been provided an improved interrupting structure 25 which leads to highly effective gas-flow conditions and to a proper centering of the arc 38 during the interrupting operation.

From the foregoing description it will be apparent that there has been provided an improved high-speed compressed-gas circuit interrupter in which the contacts separate in a highpressure atmosphere, or environment 8. The separation of the separable contacts not only causes opening of the primary blast valve 27 to result in a radial inward flow of the high-pressure fluid exhausting through the contacts, but continued opening motion effects a subsequent closure of the secondary blast valves 23a, 23b and a cessation of the exhausting gas flow occuring through both contacts. This results in the contacts being separated in a high-pressure region 8 while in the open circuit position, thereby taking advantage of the high-dielectric-strength of the high-pressure gas. As well known by those skilled in the art, this results in a minimum separation distance in the open-circuit position of the interrupter.

Certain features of the operating mechanism are set forth and claimed in U.S. Pat. application filed Nov. 18, 1968, Ser. No. 776,510 and assigned to the assignee of the instant application.

Certain other features relating to the general configuration of the circuit interrupting structure with the generally U-shape are set forth and claimed in US. Pat. application filed Dec. 9, 1968, Ser. No. 782,365 and likewise assigned to the assignee of the instant application.

Although there has been illustrated and described specific structures, it is to be clearly understood that the same were merely 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.

I claim: 1. A circuit-interrupter of the gas-flow type, combination:

a a relatively stationary tubular venting contact through which gas may exhaust; i

b. a relatively movable tubular venting contact cooperable with said relatively stationary venting contact to establish an arc and through which gas may also exhaust during interruption;

c. primary blast-valve means disposed closely adjacent the point of contact separation;

d. casing means for confining a high-pressure gas externally of said separable contacts;

e. opening of said primary blast-valve means enabling an incomprising, in

ward flow of high-pressure gas to flow from said casing means into both of said separable contacts to bring about are interruption interiorly of said tubular venting separable contacts;

f. a first contractable insulating nozzle structure supported at the relatively stationary contact and comprising a plurality of inward-biased nozzle portions disposed interiorly of an annular nozzle holder (74):: having a nozzle opens g. said first contractable insulating nozzle structure delaying application of said inward flow of gas prior to the withdrawal of said movable tubular venting contact out of said nozzle opening;

h. a second contractable insulating nozzle spaced axially along the line of contact travel from said first nozzle structure and also including a plurality of inward-biased nozzle portions;

i. said movable tubular venting contact passing interiorly through both said first and second contractable insulating nozzle structures during the closing operation of the interrupter to thereby expand the nozzle portions in both nozzle structures; and,

j. the contraction of said nozzle portions of the nozzle structures tending to center the established arc axially for better arc interruption characteristics.

2. The circuit-interrupter combination of claim 1, wherein the separable contacts themselves define the primary blastvalve means.

3. The circuit-interrupter combination of claim 1, wherein a pair of secondary blast-valves are provided downstream of the arcing region, and means are provided to open the secondary blast-valves duringthe opening operation of the interrupter.

4. The circuit-interrupter combination of claim 1, wherein leaf spring means are provided to bias the plurality of inwardmovable nozzle portions to an inward position.

5. The circuit-interrupter combination of claim 1, wherein the noule holders have boss portions to guide the radial inward and radial outward motion of the nozzle portions.

Claims (5)

1. A circuit-interrupter of the gas-flow type, comprising, in combination: a. a relatively stationary tubular venting contact through which gas may exhaust; b. a relatively movable tubular venting contact cooperable with said relatively stationary venting contact to establish an arc and through which gas may also exhaust during interruption; c. primary blast-valve means disposed closely adjacent the point of contact separation; d. casing means for confining a high-pressure gas externally of said separable contacts; e. opening of said primary blast-valve means enabling an inward flow of high-pressure gas to flow from said casing means into both of said separable contacts to bring about arc interruption interiorly of said tubular venting separable contacts; f. a first contractable insulating nozzle structure supported at the relatively stationary contact and comprising a plurality of inward-biased nozzle portions disposed interiorly of an annular nozzle holder (74)a having a nozzle opening (74a); g. said first contractable insulating nozzle structure delaying application of said inward flow of gas prior to the withdrawal of said movable tubular venting contact out of said nozzle opening; h. a second contractable insulating nozzle spaced axially along the line of contact travel from said first nozzle structure and also including a plurality of inward-biased nozzle portions; i. said movable tubular venting contact passing interiorly through both said first and second contractable insulating nozzle structures during the closing operation of the interrupter to thereby expand the nozzle portions in both nozzle structures; and, j. the contraction of said nozzle portions of the nozzle structures tending to center the established arc axially for better arc interruption characteristics.

2. The circuit-interrupter combination of claim 1, wherein the separable contacts themselves define the primary blast-valve means.

3. The circuit-interrupter combination of claim 1, wherein a pair of secondary blast-valves are provided downstream of the arcing region, and means are provided to open the secondary blast-valves during the opening operation of the interrupter.

4. The circuit-interrupter combination of claim 1, wherein leaf spring means are provided to bias the plurality of inward-movable nozzle portions to an inward position.

5. The circuit-interrupter combination of claim 1, wherein the nozzle holders have boss portions to guide the radial inward and radial outward motion of the nozzle portions.

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