US3497653A - Fluid-blast circuit interrupters with extensible movable fluid-directing nozzle - Google Patents

Description

Feb. 24, 1970 A. P. STROM ET AL 3,497,653

FLUID-BLAST CIRCUIT ERRUPTERS WI TH EXTENSIBLE VABLE FL DIRECTING NOZZLE 6' Sheets-Sheet 1 Filed Dec. 2, 1966 Feb. 24, 1970 s o ET AL 3,497,653

FLUID-BLAST CIRCUIT INTERRUPTERS WITH EXTENSIBLE MOVABLE FLUID-DIRECTING NOZZLE Filed Dec. 2, 1966 6 Sheets-Sheet 2 LOW-PRESSURE HIGH- PRESSURE SF Feb. 24, 1970 A. P. STROM ET AL 1 3,497,653

FLUID-BLAST CIRCUIT INTERRUPTERS WITH EXTENSIBLE MOVABLE FLUID-DIRECTING NOZZLE Filed 2. 1 e Sheets-Sheet a UUUUUUUU so 62 I P 725: 3

Feb. 24, 1970 A. P. STROM ET A FLUID-BLAST CIRCUIT INTERRUPTERS WITH EXTENSIBLE MOVABLE FLUID-DIRECTING NOZZLE Filed Dec. 2, 1966 6 Sheets-Sheet 6 United States Patent ABSTRACT OF THE DISCLOSURE A fluid-blast circuit interrupter is provided including means defining an orifice-shaped stationary contact having an exhaust opening therethrough. -A cooperable movable contact separates from the orifice-shaped stationary contact to establish an arc. A reservoir chamber is provided to contain a high pressure gas and blast valve means are provided for controlling the blast of high pressure gas from the reservoir into the established arc during the opening operation.

A movable insulating nozzle is provided for directing the fluid through the exhaust opening provided at the stationary contact. The differential pressure across the movable insulating nozzle is such as to retain the insulating nozzle in its extended position during arc interruption, and biasing means is provided for biasing the insulating movable nozzle to a retracted position following cessation of gas flow and following are extinction. As a result, the isolating gap, in the fully open circuit position of the interrupter, is not bridged by insulating surfaces which would tend to impair the dielectric strength of the insulating or isolating gap. I

In one arrangement, a compression spring, encircling the actuating member for the movable contact serves to bias the insulating nozzle to a retracted position. In another arrangement, a pair of support tube assemblies enclosing tension springs are provided to bias the insulating nozzle to its retracted position.

This invention relates, generally, to fluid-blast circuit interrupters and, more particularly, to fluid-blast circuit intermpters of the dual-pressure type involving a pair of separable contacts, one of which is of the orifice type, and in which an extensible fluid-directing nozzle is associated with the cooperable movable contact structure.

A general object of the present invention is the provision of an improved compressed-gas circuit interrupter having improved fluid-directing nozzle means, and additionally providing an improved retracting construction for said nozzle means to improve the dielectric conditions adjacent the arcing gap in the open-circuit position to prevent breakdown thereacross following are interruption.

Another object of the present invention is the provision of an improved fluid-blast circuit interrupter in which a pair of spaced aligned stationary contact structures are electrically bridged by a movable bridging member, and in which a movable fluid-directing orifice, or nozzle member, is picked up by the movable contact structure on the closing stroke, and is biased in the opening direction, but nevertheless maintained in its extended position by the differential gas pressures thereacross.

Still a further object of the present invention is the provision of an improved fluid-blast circuit interrupter of the type utilizing an extendible movable nozzle member associated with the movable contact structure in which the biasing means for the nozzle member is situated at such a location that in the open-circuit position of the ice interrupter, it is removed from the region of electrical stress.

According to a preferred embodiment of the invention, there is provided a relatively stationary orifice-shaped contact provided with an exhaust opening therethrough. Cooperating with the orifice-shaped stationary contact is a movable contact having a movable nozzle member surrounding the same, and directing gas flow at the established arc and through the exhaust opening. The construction is such that the movable nozzle member is carried along by the removable contact member during the closing stroke, and is retained in its extended position by differential gas pressure, so that during the arcing period, the gas will be directed along the arc and through the exhaust opening provided by the stationary contact to facilitate arc interruption.

One arrangement for biasing the nozzle member to a retracted position utilizes a compression spring surrounding the movable contact-actuating rod. Another modified arrangement utilizes one or more movable tension-tube assemblies, which not only serve to surround the innerdisposed tension springs, but additionally serve a supporting function for the extendible nozzle member.

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

FIGURE 1 is a side elevational view of a three-phase fluid-blast circuit interrupter incorporating the principles of the present invention;

FIG. 2 is an end elevational view of the three-phase circuit interrupter of FIG. 1;

FIG. 3 is an enlarged vertical sectional view taken through one of the modular units of FIGS. 1 and 2, taken substantially along the line IIIIII of FIG. 2, the contact structure being illustrated in the closed-circuit position;

FIG. 4 is an enlarged vertical sectional view taken substantially along the line IVIV of FIG. 1, the contact structure being illustrated in the closed-circuit position;

FIG. 5 is an enlarged vertical sectional view taken through the separable contact structure and the associated extendible nozzle, the contact structure being illustrated in the closed-circuit position;

FIG. 6 is a view similar to that of FIG. 5, but showing the disposition of the several parts during the arcing period with the nozzle member extended due to the differential gas pressure thereacross;

FIG. 7 is a view similar to that of FIGS. 5 and 6, but showing the disposition of the several parts in the fully open-circuit position with the movable nozzle member retracted;

FIG. 8 is an enlarged vertical sectional view taken through the blast-valve operating linkage and conduit structure;

FIG. '9 is a vertical sectional view of a modified type of contact and nozzle actuating structure utilizing a different biasing means for the movable nozzle member; and,

'FIG. 10 is a view similar to that of FIG. 9, but illustrating the disposition of the several parts during the arcing period.

Referring to the drawings, and more particularly to FIGS. 1 and 2 thereof, it will be observed that there are provided three arc-extinguishing assemblages A, B and C for a three-phase fluid-blast circuit interrupter 1. As more clearly illustrated in FIG. 1, each arc-extinguishing assemblage for a particular phase, for instance arcextinguishing assemblage A, comprises three seriallyrelated modular units 2 electrically interconnected by connecting elements 3, and being connected to a separate current transformer structure 4.

FIGS. 1 and 2 collectively show how the modular units 2 are supported an adequate distance above ground potential by insulating supporting columns 5 interbraced by insulating laterally-extending tie-rods 6. As shown, the lower ends of the insulating columns 5 and the tie-rods 6 are fixedly secured to a lower grounded angle-iron framework 8 supporting the mechanism and gas-control equipment within a mechanism compartment 10.

With reference to FIG. 3, it will be observed that each of the modular units 2 includes a pair of diagonallyextending terminal bushings 11, which extend interiorly into a generally spherical tank structure 13 containing a suitable gas 14, such as sulfur-hexafluoride (SP gas, at a relatively low pressure, say, for example, 60 p.s.i. It will be noted that secured to the inner extremities 11a of the terminal-bushing structures 11 are a pair of laterally-spaced orifice-shaped stationary contacts 16 having exhaust openings 17 therethrough, leading into exhaust chambers 18 which communicate with the hollow interiors 20 of the terminal studs 22 associated with the terminal bushings 11. The gas 14 may be exhausted upwardly through the hollow terminal studs 22 of the terminal bushings 11, and be returned within the region 23 externally of the hollow terminal studs 22 and be exhausted into the general interior 25 of the tanks 13 through openings 27. Projecting laterally from the exhaust chambers 18 of the stationary contact structures 16 are two resistance assemblages 28 (FIG. 4), which support wire-wound resistance elements 29, one end of each of which is electrically connected to a stationary arcing horn 31 (FIG. 3), which extends Within the exhaust opening 17 of each stationary contact 16. As will be understood by those skilled in the art, when the upper end of the are 33 (FIG. 6) attaches to the arcing horn 31, the two resistance elements 29 will be in electrical parallel, and will serve to reduce the amperage of the current being interrupted and will also improve the power factor, and reduce the rate of rise of recovery voltage.

Supported by a laterally-extending conducting bus-bar structure 35 (FIG. 3) is a pair of laterally-spaced relatively stationary contact casting structures 36 generally disposed vertically in line with the upper stationary contact structures 16, and serving to support extensible fluiddirecting nozzle members 38, which are biased in a downward opening direction. FIGS. 5-7 more clearly illustrate the operating movement of the nozzle members 38, which assist in defining volumes 40, Within which the compressed gas is transmitted by means of a conduit means 42 and a blast-valve structure 44, more clearly illustrated in FIG. 8 of the drawings, and described hereinafter.

Bridging each pair of vertically-spaced stationary contact casting structures 16, 36 is a movable contact-bridging member 46 secured to the upper end of an actuating, or contact-operating rod 48, the lower end 48a (FIG. 3) of which is fixedly secured to the outer extremity of a crossarm 50, in turn actuated vertically by a pair of insulating operating rods 52 extending upwardly within each insulating column 5. It will be obvious that vertical reciprocal movement of the insulating operating rods 50 within each column 5 will effect, through the cross-arm or traverse 50, vertical opening and closing movement of the pair of movable bridging contacts 46 disposed at the outer ends of the cross-arm 50. :Each movable bridging contact 46 will electrically interconnect its associated pair of relatively stationary contact casting structures 16, 36 in a manner illustrated more clearly in FIG. 5 of the drawings.

With further reference to FIG. 5, it will be noted that each contact-operating or actuating rod 48 has a lateral projection 54, which picks up a cross-member 56, which mechanincally interconnects a pair of movable nozzle support rods 58. The support rods 58 extend upwardly into the gas entrance chambers, or volumes 40 defined by inner and outer cylindrical portions 60, 61 of casting 36 through openings 62. It will be observed that the lower ends 46a of the movable bridging fingers 46 make sliding contacting engagement with the inner surface 61a of the inner conducting cylindrical portion 61 of casting 36. The upper ends of the supporting rods 58 are secured by a locking ring 64 and bolts '65 to the lower extermity 38a of the movable nozzle, or orifice member 38. The arrangement is such, as more clearly illustrated in FIG. 5, to carry the movable nozzle member 38 upwardly with the movable bridging contact structure 46, so that in the closed-circuit position, as illustrated in FIG. 5, the nozzle 38 abuts, or is in close proximity to, the lower side 16a of the orifice-shaped stationary contact 16.

In the closed-circuit position, as is illustrated in FIGS. 3 and 5, the electrical circuit passes through the hollow terminal stud 22 of one bushing 11, through the conducting walls of the exhaust chamber 18, relatively stationary contact 16, movable bridging member 46, relatively stationary contact portion 61a of inner cylindrical member 61 of casting 36, through the transverse bus framework 35 and in similar manner through the right-hand arcextinguishing unit 19.

It will be observed that the conducting bus-bar structure 35 not only serves to support the relatively stationary contact casting structures 36, but additionally carries the current in the closed position through the inner conducting portions 61 of casting 36. Moreover, the operating rods 48 and cross-arm 50 are of relatively lightweight construction. These features are set forth and claimed in United States patent application filed Dec. 2, 1966, Ser. No. 598,807, by Charles F. Cromer and Charles B. Wolf, and assigned to the assignee of the present application. The contact structure 46 is described in detail and claimed in U.S. patent application filed Dec. 2, 1966, Ser. No. 598,857, and likewise assigned to the assignee of the present invention.

The concept of utilizing a generally spherical exhaust tank, together with a high-pressure cylindrical tank below the same is set forth and claimed in United States patent application filed Dec. 2, 1966, Ser. No. 586,856 by Winthrop M. Leeds and Albert P. Strom, and likewise, assigned to the assignee of the present application.

OPENING OPERATION During the opening operation suitable mechanism (not shown) disposed within the mechanism compartment 10, such as that, for example, set forth in U.S. patent application filed June 12, 1964, Serial No. 374,708, now U.S. Patent 3,291,947, issued Dec. 13, 1966 is released to effect downward opening movement of the several insulating operating rods 52 disposed within the individual insulating column structures 5. As will be obvious, the downward opening movement of the insulating rods 52 will effect, through the crossbars 50 and the vertical movable contact-operating rods 48, downward opening movement of the two movable bridging contact assemblages 46. With reference to FIG. 8, it will be observed that downward movement of the operating rods 52 will correspondingly cause counterclockwise rotative travel of the blast-valve lever 66 around stationary pivot 67 and thereby effect rightward opening movement of the blast valve 68. This will permit gas flow from the high-pressure storage region 69 upwardly through conduit 70, past the blast valve 68 and through a connecting conduit 71 into the entrance volume 40, which is defined by the inner and outer cylindrical portions 60, 61 of casting 36 and adidtionally by the insulating nozzle member 38 itself. The entrance of gas flow into the entrance region 40 will cause a flow of high-pressure gas past the established arc 33 (FIG. 6), and will exhaust through the orifice opening 17 into the exhaust chamber 18. In more detail, the separation of the contact structures 16, 46b will draw an arc indicated by the dotted line 32 (FIG. 6),

which will be carried by the high-pressure gas flow to terminate upon arcing horns 31, 460, as shown in FIG. 6. The high-pressure gas flow directed by the nozzle member 38 will extinguish the are 33, the gas flow exhausting within the exhaust chambers 18.

During this time the nozzle member 38 is maintained in its extended position by the diflerential gas pressure present within the entrance volume 40 as compared with the pressure in region 25, even though at this time the movable bridging contact structure 46 is moving downwardly to open, and the compression spring 72, encircling the contact-operating rod 48, is being compressed.

Following the interruption of the are 33, (FIG. 6), the blast valve 68 will reclose, shutting off the flow of high-pressure gas, and leakage will dissipate the pressure within the entrance region 40, thereby permitting the compression spring 72 to retract the movable nozzle member 38 to its lowered position, as more clearly illustrated in FIG. 7 of the drawings. 1

It will be observed that in the open-circuit position of the interrupter 1, as is illustrated in FIG. 7, there is no insulating means interposed in the isolating gap 73, which would tend to cause tracking, and possibly might adversely affect the dielectric conditions at the disconnect gap 73 to induce electrical breakdown.

FIGS. 9 and 10 illustrate a variant type of biasing means for the movable nozzle members 38, which comprises a plurality of tension-tube assemblages 76, the upper ends of which are secured by a locking ring 78 to the lower extremity 38a of the nozzle member 38, and the inner tension springs 80 therein having their lower ends 80a secured directly to the tank structure 13. As was the situation in the previous embodiment of the invention, the cross-arm 50a picks up the tension tubes 82 by a flange portion 82a thereof. The tension tubes 76 serve as supports for the movable nozzle 38, and carry the same upwardly with the movable bridging contact structure 46 during the closing operation of the interrupter 1. The dotted lines in FIG. 9 illustrate the disposition of the several parts in the closed-circuit position of the interrupter.

FIG. 10 illustrates how the movable nozzle member 38 is again retained in its extended position during the arcing period due to differential gas pressure within the entrance volume 40 as compared to the pressure within region 25. Even though the movable bridging contact structure 46 has moved downwardly, nevertheless the diiTerential gas pressure within the entrance volume 40 is adequate to maintain the nozzle member 38 in its extended position directing the gas flow through the exhaust openings 17 provided in the stationary contacts 16. Are interruption is achieved in a manner similar to that described hereinbefore and following a dissipation of the gas pressure within the entrance region 40, due to the closing of the blast valve 68, the biasing force of the tension springs 80, provided within the tension-tube assemblies 76, will effect downward retracting opening movement of the nozzle members .38 to their fully 6 open position, as is illustrated in FIG. 9 of the drawings. From the foregoing, it will be apparent that we have provided an improved extendible nozzle construction 38 for eifectively directing the high-pressure gas flow during the opening operation, and have additionally pro-- vided means for removing the insulating nozzle member 38 from the disconnect gaps 73 to improve the dielectric conditions in the open-circuit position of the interrupter.

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.

We claim as our invention:

1. A fluid-blast circuit interrupter including means defining an orifice-shaped stationary contact having an exhaust opening therethrough and a cooperable movable contact separable therefrom to establish an arc, an actuating member (48) to effect opening and closing movement of the movable contact, means defining a source of fluid under pressure, blast-valve means for controlling a flow of high-pressure fluid from said source, a movable insulating nozzle for directing fluid through said exhaust opening picked up by said actuating member on the closing stroke of said actuating member and abutting said orifice-shaped stationary contact, means biasing said movable insulating nozzle away from said stationary contact, said movable insulating nozzle being in its extended position in the closed-circuit position of the interrupter, conduit means from said blast-valve means leading into a volume defined at least partially by said insulating nozzle, whereby the gas pressure in said volume will retain said nozzle in its extended position during arc interruption.

2. The fluid-blast circuit interrupter according to claim 1, wherein the biasing means comprises a compression spring encircling said actuating member.

3. The fluid-blast circuit interrupter according to claim 1, wherein the biasing means comprises one or more supporting tube assemblies secured to the remote end of said nozzle.

4. The combination of claim 3, wherein each supporting tube assembly includes an inner tension spring.

References Cited UNITED STATES PATENTS 2,790,050 4/1957 Fawdrey et a1. 200-148 3,214,545 10/1965 Cromer. 3,214,546 10/1965 Leeds 200145 X 3,218,421 11/1965 Latour 200148 FOREIGN PATENTS 524,983 8/ 1940 Great Britain.

ROBERT S. MACON, Primary Examiner ROBERT A. VANDERHYE, Assistant Examiner

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