US3551624A - Gas-flow circuit interrupters having improved orifice and contact constructions - Google Patents

Description

United States Patent [72] lnventor William H. Fischer Pittsburgh, Pa.

[21] Appl. No. 576,583

[22] Filed Sept. 1,1966

[45] Patented Dec. 29, 1970 [73] Assignee Westinghouse Electric Corporation Pittsburgh, Pa.

a corporation of Pennsylvania [54] GAS-FLOW CIRCUIT IN TERRUPT ERS HAVING IMPROVED ORIFICE AND CONTACT 150G, 148, 144APRl, 146, 148.7; 335/Examiner, 201,18,195;317/Examiner,11

[56] References Cited UNITED STATES PATENTS 1,336,069 4/1920 Conrad 200/150(G) 2,281,385 4/1942 Saint-Germaineta1...... 200/148(.1) 2,381,244 8/1945 Arnold ZOO/150(6) 2,897,408 7/1959 Kesselring et a1 335/195X 2,913,559 11/1959 Cromer 1 200/148(.1) 2,933,575 4/1960 Baker 200/l48(. 1) 3,172,010 3/1965 Diebold 317/11 3,238,340 3/1966 Lerch 200/148(.1) 3,268,687 8/1966 Waghorne et a1 200/144(.2)X 3,315,056 4/1967 Furukawa et a1. 335/18X FOREIGN PATENTS 828,466 2/1938 France ZOO/148.1 1,142,201 1/1963 Germany... ZOO/148.1 1,206,056 12/1965 Germany ZOO/148.1

Primary Examiner-Robert S. Macon AnorneysA. T. Stratton, Clement L. McHale and Willard R.

Crout PATENTEDUECZQISYU $55 5 SHEET 1 OF 4 A 40 L J WITNESSES INVENTOR @mmaggm William H. Fischer BY jg MMATTORNEY GAS-FLOW CIRCUIT INTERRUPTERS HAVING IMPROVED ORIFICE AND CONTACT CONSTRUCTIONS This invention relates generally to circuit interrupters of the fluid-blast type and, more particularly, to improved fluid-blast circuit interrupters having orifice constructions to effectively directthe gas flow.

A general object of the present invention isto provide an improved'orifice-type circuit interrupter in which the gas flow is more effectively directed toward the arc.

Still a further object of the present invention'is to provide an improved fluid-flow circuit interrupter in which clogging," or the generation of considerable back pressure during interruption, is avoided. I

Still a further object of the present invention is the provision of an improved gas-flowcircuit interrupter in which more effective arc transfer to an arcing contact is obtained toeither insert accelerating coils, or resistance means, into the circuit.

Still a further object of the present invention is the provision of an improved gas-flow circuit interrupter in which the power required in theoperating mechanism may be considerably reduced by theelirnination of high back-pressure forces- "generated by arcing within the orifice.

I of an improved orifice configuration for a gas-flow type of circuit interrupter. I

Yet a further object of the present invention is the provision of an improved gas-flow type of circuit interrupter in which a circulation of the gas flow is provided on the upstream side of the orifice. I g

In the application filed Sept. 1', 1966, Ser. No. 576,616, now U.S. Pat. No. 3,524,958 by Russell E. Frink, and assigned to the assignee of the instant application, there is illustrated and described a fluid-blast circuit interrupter in which electromagnetic means are provided, assuming the form of accelerating coils, to increase the piston-driving efforts during heavy faultcurrent interruption.

' It is a further object of the present invention to provide an improved circuit interrupter of the aforesaid type, as described in the Frink patent application, which will have an improved orifice construction and piston-driving arrange- I'I'ICIII.

A further form of the aforesaid Frink' patent application, as manufactured commercially,- is set forth in applicationfiled Sept. l, 1966, Ser.. No. 576,740, by Russel E. Frink and William I-l. Fischer, and assigned to the assigneeof the instant application.

Another object of the present invention is to incorporate principles of the present invention into the commercial form of apparatus of the puffer type, which utilizes the electromagnetic principles for additional fluid-driving effort, as taught by the first-mentioned Frink patent application.

Additional objects andadvantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIG. I is a vertical sectional view taken through a puffer, or piston-type gas-flow form of circuit interrupter, the contact structure being illustrated in the partially open-circuit position;

FIG. 2 is a vertical sectional view taken through a modified type of fluid-flow circuit interrupter incorporating the principles of the present invention, the contact structure again being illustrated in the partially open-circuit position;

FIG. 3 illustrates a further form of the fluid-flow type of circuit interrupter, again the contact structure being illustrated in the partially open-circuit position;

FIG. 4 is a vertical sectional view taken through a further form of the present invention, the auxiliary current are being indicated to show the insertion of the two accelerating coils;

FIG. 5 is a diagrammatic view of the coil connections for the circuit interrupter of FIG. 4;

FIG. 6 illustrates, fragmentarily, in vertical cross section, a further variant of the fluid-flow circuit interrupter of FIG. 4, incorporating a circulating type of gas flow on the upstream side of the orifice structure, again the contact structure being illustrated in the partially open-circuit position;

FIG. 7 illustrates a further form of orifice and contact structure illustrating an additional embodiment of the principles of the present invention, the contact structure. b ing illustrated in the closed-circuit position;

FIGS. 7A, 7B and 7C illustrate, fragmentarily, different separation distances of the separable contacts of FIG. 7 and the sequence of arc establishment;

FIG.-8 illustrates diagrammatically the coil connections for the circuit interrupter of FIG. 7; and, I v

FIG. 9 illustrates a further form of a fluid-flow circuit interrupter incorporating the principles of the present invention, and bringing into series circuit a resistance means to facilitate circuit interruption.

I Referring to the drawings, and more particularly to FIG. I thereof, the reference numeral 1 generally designates a fluidflow type of circuit interrupter. As will be recognized by those skilled in the art, the fluid may be of different types, such as gas, oil, a various liquids, carbon dioxide (CO or preferably, and by way of example, sulfurhexafluoride (SE6) gas under a pressure of, say, for example, 60 p.s.i.

In order to create a flow of gas toward the are 3 established between the stationary contact 4 and the movable arcing contact 6, relative movement between a movable operating cylinder 7 and a stationary piston 8 is provided. Such movement may be effected bymeans of a pair of operating rods 9 pivotally connected, as at 10, to a rear portion 7a of the movable operating cylinder 7.

As shown in FIG. 1,- the head 12 of the movable operating cylinder 7 carries an insulating orifice 14 having a constricting portion 15 and a diverging portion 16. t

As shown in FIG. I, the movable contact structure comprises a plurality of circumferentially disposed main contact fingers 18 and a tubular arcing contact portion 6 collectively constituting a movable contact structure, generally designated .by the reference numeral 20.

Reference may be had to US. Pat. No.'3,-l 14,815, issued Dec. 17, 1963 to Easley et al., and assigned to the assignee of the instant invention, for a commercial form of a puffer,'or piston-type circuit interrupter, which'gencrates compressed fluid-flow, and forces the same through an associated orifice structure into engagement with an established arc.

During the opening operation, the driving rods 9 are moved toward the left by suitable mechanism, not shown, and carry the operating cylinder 7 together with the movable contac structure 20 and orifice structure 14 therewith.

An arc is initially established between the movable main contact fingers l8 and the tubular vented stationary contact tube 4. However, the gas flow and the slight clearance between the inner disposed arcing tube 6 and the outer stationary contact tube 4 immediately causes the arc to be transferred to the inner vented tubular arcing contact 6, where it is subjected to a gas flow, as caused by the relative movement between the operating cylinder 7 and the stationary piston member 8. The are is soon interrupted, and continued opening movement of the operating cylinder 7 and movable contact structure 20 inserts an isolating gap into the circuit. During the closing operation, the operating mechanism functions to cause nightward closing movement of the movable operating cylinder 7, carrying with it the movable contact structure 20 and the. orifice member 14. The closing movement continues until the main contact fingers 18 engagethe external side surface 40 of the stationary vented arcing contact 4, and the arcing contact 6 is inserted into the stationary contact 4 in a manner indicated by the dotted lines 21.

It will be observed that the movable contact structure 20 is located a distance D on'the upstream side of the orifice constriction 15 of the orifice structure I4. This ensures that there will be a permissible venting into the interior 23 of the movable'eontact tube 24 carrying the movable contact structure 20 a at its right-hand extremity.

The double-venting action through the interior 23 of the movable contact tube 24, together with the venting which occurs within the region 26 interiorly of the stationary venting provided ready access to the venting 23 provided through the movable contacttube 24. r

FIG. 2 shows a modified type of gas-flow interrupter,

1 generally designated by the reference numeral 30, similar in 1 many respects to that set forth previously in connection with FIG. 1 of the drawings; however, it will be noted that the orifice 31 has a relativelyclose fit, as at 31a, with the external surface of the stationary venting contact tube 4. However, because of the provision of the distance D of the position of the movable contact structure 20 on the upstream side of the orifice restriction 15, there .is provided a venting action throughthe interior 23 of the movable contact tube 24, and

consequently clogging is eliminated.

FIG. 3 illustrates a modified type of circuit interrupter,

generally designated by the reference numeral 40, in whichv the head 41 of the movable operating cylinder 42 has vents 43 provided therein, which communicate with a central region 46 closed by a unidirectional valve 48 biased to the closed posi- ,tion by a spring 49. 'As a result, the modified type of circuit interrupter 40 shows the flow from the upstream hollow contact exhausted out through the piston head 41, and a pressure valve 48 which maintains pressure at low currents. Again it will be noted that there is provided an orifice 14 with a diverging portion 16', and that the movable contact structure 20 is disposed upstream of the orifice constriction 1 5.

FIG. illustrates a further form of the invention in which electromagnetic means 50 are provided to facilitate cylinder movement during high fault-current interruption. The

reference numeral 56 generally designates the circuit interrupter illustratedin FIG. 4 having a movable accelerating coil 55, which is attracted to a stationary accelerating coil 56, the latter being embedded in the stationary piston 58. During the opening operation, the arc is transferred to the centrally disposed arcing contact or movable probe 60, thereby inserting the two accelerating coils 55, 56 serially into the circuit, as

illustrated by the diagrammatic view of FIG. 5.,

It will be noted that due to the venting around the movable arcing contact 60 that the arc 6i is maintained on the arcing contact or probe 60, and is not permitted to retransfer back to the main contact fingers 1:8, In addition, the movable contact structure 62 is again disposed a certain distance D on the upstream side of the orifice constriction so that venting may take place through the movable hollow contact tube 24.

As shown in FIG. 4, a connection 63 is provided between the arcing contact or probe 60 and the movable accelerating coil 55. Another connection 64 is provided between the movable coil 55 and the accelerating coil 56 by means of a stationary finger 65 bearing upon the movable conductor bar 64 connectedto the movable accelerating coil 55. A connection 66 is utilized between the stationary contact finger 65 and the stationary accelerating coil 56. Another connection 67 is provided between the stationary accelerating coil 56 and a contact finger 68, which bears upon the outer surface of the movable contact tube 24 and carries the line connection L.

During the opening operatiomthe initial movement of the movable contact structure 62 causes an arc to be established between the main contact fingers l8 and the stationary venting contact 4. Because of the gas flow flowing in the direction indicated by the arrows, and the slight clearance between the movable probe 60 and the outer-disposed stationary contact tube 4 the main current are is transferred to the central arcing contact or probe 60, whichinsefis the two accelerating coils 55, 56 into the circuit. Due'to the attraction between the accelerating coils 55,56, the operating cyli'nder 7 will be assisted in its leftward opening movement, thereby imposing less power requirements upon'ithe operating mechanism" not shown). Reference may be had, to applicationfiled Sept. 1, I966, Ser. No. 576,616for furt libry'inthis connection.

FIG. 6 illustrates a further fo'rm of the structure illustrated in FIG. 4 in which a circulating flow about the are 61 is obtained. As shown in FIG. 6, the movable contact 70 is solid, and a recirculating shield 71 is provided together'with perforations 72 through the rear portions of the main contact "fingers 18, to provide a recirculating flow adjacent thecentral arcing "probe 60. This prevents arc retransfer back to the main contact fingers l8, and assists in the correct guiding of the "gas flow. I l

FIG. 7 illustrates a commercial form of the invention, as set.

out in detail in the application filed Sept. 1 1,966 Ser'. No..-

576,740 by Russell E. Frink and William H. Fischer, andi assigned to the assignee of the instant application. g .As shown in FIG. 7,'there is provided a stationarymgeta'llic orifice 73. surrounded by a plurality of stationaryfmetal lic main contact fingers 74. Cooperable with the stationary contact structure 75 is a movable contact structure g'enerally designated by the reference numeral 76. The movableieontact structure 76 comprises an outer main contact tube 7.7 and an inner arcing tube 78 insulated therefrom as at 781),: 7 movable contact structure 76 is mechanically connec spider member 80 to a movable piston assembly 81 comprr ing a piston 82 operable within a stationary operating cylinder 83. An accelerating coil'85 is carried bythe movable piston assembly 81. Bifurcated rod ends 87, togethebwith bolts 88,

:pivotally connect operating links to the movable contact .and piston assembly 81 from an operating mechanism (not shown).

Connected rigidly to the movable piston assembly 81 is a movable accelerating coil assembly 92 comprisinga movable coil 93 embedded within an insulated head portion 94. A movable auxiliary contact 96 is secured, as by a threaded connection 97, to the right-hand extremity of the main contact tube 77 and separates from a stationary auxiliary contact '79. This movable auxiliary contact 96 moves to the right during the opening operation, and with the assistance of the are established between contacts 74, 77 inserts into series circuit the movable piston coil 85, the stationary coil 98, and the movable-driving coil 93. 'As set forth in the aforesaid application Ser. No. 576,740, the two accelerating coils 85, 98 attract, whereas themovable coil 93 is repelled from the stationary accelerating coil 98. The coil connections are set forth in FIGS ofthe drawings.

Three positions of the mov'able'contact assembly 76 during the opening operation are shown in FIGS. 7A, 7B and 7C. It will be noted that the main arc is transferred to themovable arcing vented tube'78 to insert the three accelerating coils serially into the circuit. Y a

The scheme, as shown in FIG. 7, has four design concepts similar to those described in FIGS. 1-6 and 9. In FIG. 7 the gas flow entering the inner arcing tube 78 aids in positively transferring the arc and maintaining the transfer of the are from the main contact tube 77 to the inner arcing tube 78 when this transfer is used to cut in the driving coils 85, 98, 93. Experimental tests have shown this to be especlallyimportant at currents of 20,000 amperes and above. A second similarity is that of having the gas flow entering inner arcing tube 78 in FIG. 7 upstream of the minimum constriction'lS of the orifice 73. This construction helps relieve clogging in the orifice throat and hence reduces back pressure when high current arcs are drawn. This improved flow condition allows the'use of a smaller driving forcem'e chanism and also enhances"interruption. Experimental tests have shown this to be important at currents above 20,000 amperes. A third similarity is the broad idea of having flow into elements of both the moving and stationary contact members 73, 78 instead of only one. Gas flow enters the inner arcing tube 78 and orifice 73 of the interrupter of FIG. 7. This has the advantage of having longer are lengths near current zero which enhances interruption as shown in FIG. 7C. A fourth similarity is that of having a tapered orifice l6 downstream of the minimum constriction 15, as shown by the design orifice 73 in FIG. 7. This allows the heated gas to expand, which improves the gas-flow conditions and therefore enhances interruption.

FIG. 9 illustrates a further modification of the invention generally similar to that of FIG. 4, previously described, with the exception that in place of inserting accelerating coils 55, 56 into the circuit, instead an impedance 100, or resistance means R, is inserted into the circuit during the opening operation. The general orifice and contact arrangement may be identical to that set forth in FIG. 4, previously described, the only difference being that in place of accelerating coils 55, 56, a stationary resistance means 100 is provided.

' As well known by those skilled in the art, the insertion of resistance 100 into the circuit during the opening operation not only reduces the amperage of the circuit to be interrupted, but additionally improves the power factor. 7

From the foregoing it will be apparent that there is provided improved contact and orifice constructions, which assist in preventing clogging, and assist in the desired direction of gas flow to facilitate interruption.

Although there have 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.

lclaim:

l. A fluid-blast circuit interrupter including a stationary contact and a cooperable movable contact structure separable to establish a main-current arc, said movable contact structure including a main movable contact and a movable arcing contact insulated from said main movable contact, fluid-forcing means including piston means comprising an operating cylinder member and a piston member relatively movable with respect to each other, said movable contact structure being carried by one of said relatively movable members, electromagnetic means for assisting in the fluid-driving motion of said piston means comprising at least two accelerating coils, one of said accelerating coils being a part of each of said relatively movable members, said accelerating coils both being connected in series with said movable arcing contact, and venting means being provided around said movable arcing contact to facilitate and maintain arc transfer to said movable arcing contact to insert the two accelerating coils into the series circuit of the interrupter.

2. The fluidblast circuit interrupter of claim 1, wherein the movable contact structure is carried by a movable piston.

3. The fluid-blast circuit interrupter of claiml, wherein the venting means comprises a movable tubular vented arcing contact.

4. The fluid-blast circuit interrupter of claim 1, wherein the movable contact structure is carried by a movable operating cylinder.

5. The fluid-blast circuit interrupter of claim 1, wherein an orifice structure having a constriction is provided, and the movable arcing contact is located upstream of the minimum constriction.

6. The fluid-blast circuit interrupter of claim I, wherein the venting means comprises a vent opening through the stationary contact.

7. The fluid-blast circuit interrupter of claim 1, wherein the venting means comprises a vent opening through both the stationary contact and also the movable arcing contact.

8. The fluid-blast circuit interrupter of claim 1, wherein the piston means is operated by a linkage connected to a movable operating cylinder, and the movable arcing contact comprises a vented conducting tube,

9. A fluid-blast circuit interrupter including a relatively stationary contact and a cooperable movable contact structure separable to establish a main-current are, said movable contact structure including a main tubular movable contact and an interiorly disposed tubular arcing contact insulated from said main movable tubular contact, fluid-forcing means including piston means comprising a relatively stationary operating cylinder and a movable piston movable therein, the movable piston carrying the movable contact structure therewith, electromagnetic means for assisting in the fluiddriving motion of said piston means comprising at least two accelerating coils, one of said accelerating coils being carried by the movable piston and the other accelerating coil affixed to the relatively stationary operating cylinder, said accelerating coils both being connected in series with'the movable tubular arcing contact, and venting means being provided through said movable tubular arcing contact to facilitate and to maintain arc transfer to said movable tubular arcing contact to thereby insert the two accelerating coils into the series circuit of the interrupter.

10. The combination of claim 9, wherein the relatively stationary contact is hollow and the fluid-blast vents at least partially through the hollow stationary contact.

11. The combination of claim 10, wherein the hollow stationary contact has a restriction, and the movable tubular contact is located upstream of the restriction in the closed-circuit position of the interrupter.

12. The combination of claim 9, wherein one or more piston rods are mechanically connected to the movable piston and cause the actuation thereof.

13. The combination of claim 9, wherein the stationary operating cylinder has a closed head portion, and the secondmentioned accelerating coil is supported in said closed head portion of the stationary operating cylinder.

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