US3311726A - Puffer-type fluid-blast circuit interrupter with pressurized casing for actuating driving piston - Google Patents

Description

March 28, 1967 w. A. FISH, JR 3,311,726

PUFFER-TYPE FLUID-BLAST CIRCUIT INTERRUPTER WITH PRESSURIZED CASING FOR ACTUATING DRIVING PISTON 2 Sheets-Sheet 2 Filed Oct. 5, 1964 WITNESSES INVENTOR 3 William A. Fish,dr

ATTORNEY United States Patent PUFFER-TYPE FLUID-BLAST CIRCUIT INTER- RUPTER WHTH PRESSURIZED CASING FOR ACTUATKNG DRIVING PESTON William A. Fish, Jr., Wilkins Township, Allegheny County, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed Oct. 5, 1964, Ser. No. 401,603 3 Claims. (Cl. 260-148) This invention relates to fluid-blast circuit interrupters in general, and, more particularly, to improved fluidblast circuit interrupters of the type in which a puffertype piston structure is actuated by the fluid pressure within a pressurized interrupting unit.

In United States patent application, filed Nov. 18, 1959, Ser. No. 853,974, now US. Patent 3,114,815, issued Dec. 17, 1963 to Robert L. Hess, James M. Telford and Gilbert J. Easley, and assigned to the assignee of the instant application, there is illustrated and described a single-break type of circuit interrupter in which mechanical operation of a puffer structure is acchieved by mechanical means with a linkage connected to ground potential. It is a general object of the present invention to improve upon the general type of interrupting structure set forth in the aforesaid patent application rendering it of simplified construction, of more economical manufacture, and of highly reliable interrupting performance, having associated therewith a minimum number of control lines and also a minimum number of electrical circuits.

Another object of the present invention is the provision of an improved circuit-interrupting unit of the fluid-blast type in which a self-contained pressurized casing is provided, and the pressure provided within said interrupting casing is utilized for effecting opening operation of an associated puffer structure.

Still another object of the present invention is to provide an improved simplified-type of puffer circuit interrupter using a highly efiicient arc-extinguishing gas, such for example, as sulfur hexafluoride (SP gas.

Still a further object of the present invention is the provision of an improved interrupting unit having a simplified contact structure adaptable for facilitated maintenance and involving a minimum number of parts.

An additional object of the present invention is the provision of an improved puffer-type interrupting device in which no complicated and massive mechanical linkage is necessary between the circuit-breaker contacts and ground potential. It is obvious that a reduction of the mass of the moving parts will, consequently, result in faster breaker operation.

Still a further object of the invention is the provision of an improved puffer-type interrupting unit in which full driving force is maintained to the end of the opening stroke, thereby resulting in maximum puffer pressure and maximum interrupting effort available to the end of the opening stroke.

Another object of the invention is the provision of an improved type of puffer interrupting unit in which a hollow cylindrical interrupting casing is provided having as an end closure member thereof a unitary operating cylinder carrying as a component part thereof a piston structure for effecting arc extinction.

In accordance with one embodiment of the present invention, there is provided a longitudinal hollow cylindrical pressurized casing having a terminal plate closing one open end thereof and carrying a contact post axially of the casing. A stationary contact is affixed to the inner extremity of the stationary contact post, and has cooperable therewith a relatively movable contact structure associated with a fluid-driving means, According to one arrangement, the fluid-driving means constitutes a piston 3,31 L725 Patented Mar. 28, 1967 operable relatively to an operating cylinder for compressing fluid and ejecting the same through an associated orifice structure into the established are to assist in effecting the extinction of the same. The movable piston structure is actuated by a driving means constituting a driving piston reciprocally operable within a driving cylinder with one face of the driving piston constantly exposed to the pressure within the casing. To effect opening and closing motion of the contact structure and a concomitant blasting of fluid pressure, means are provided to alternately pressurize and exhaust the other face of the driving piston within the driving cylinder. For facilitated maintenance, preferably the driving cylinder constitutes a terminal casting which closes the other end of the casting means, and thereby may readily be removed as a unit for inspection and possible replacement of eroded parts. It is contemplated that the casing is disposed up in the air an adequate distance above ground potential by a grounded supporting framework, which may be attached adjacent the midportionof the casing, with the casing itself extending in a generally horizontal direction.

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 vertical sectioinal view taken through a circuit interrupter embodying features of the present invention, the contact structure being illustrated in the closed-circuit position;

FIG. 2 is a diagrammatic view of the pneumatic con trol circuit for actuating the contact structure of the circuit interrupter of FIG. 1 to the open and closed-circuit positions, the parts being shown in the closed-circuit position of the interrupter, corresponding with the disposition of the parts illustrated in FIG. 1;

FIG. 3 is a fragmentary vertical sectional view taken through the driving cylinder illustrating the ultilization of a bellows construction to prevent leakage of gas out of the casing means;

FIG. 4' is a fragmentary detailed view showing the possibility of utilizing a two-part casing means instead of a single unitary casing means, as illustrated in FIG. 1; and,

FIG. 5 is a vertical sectional view taken through the pneumatic control valve illustrating the same in the exhausted condition.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a fluid-blast circuit interrupter of the type in which a blast of fluid, obtained by puffer action, is forced across the separating contact structure 2 to bring about are eX- tinction. As shown, generally the circuit-interrupting structure 1 includes an upstanding frame support 3 and a generally horizontally-extending pressurized casing 4. The pressurized casing 4 has a thermal cap 5 at one end thereof, which serves to support a relatively stationary contact post 6. The movable cooperating contact structure 7 comprises a plurality of circumferentially-disposed contact fingers 8 and an arcing tip portion 9, which extends interiorly within a cooperable recess 10 provided at the extremity of the stationary contact 6. Serving the purpose of opening and closing the movable contact structure 7 and an associated piston device 11 is a driving piston 12 operable within an operable cylinder 13, the latter comprising a casting structure 14, which additionally serves as aterminal end plate 15, as shown.

Movable within the operating cylinder 13 is the driving piston 12, having a piston rod 12a which has a contact finger collector 16 associated therewith. It, will be noted that the piston rod 12a functions as a movable contact rod. The piston rod 12a has an extension 12b on the other side of the piston 12, which may be guided by an aperture 15a in a weatherproof shield casting 15b affixed in any suitable manner to the terminal end plate portion 15, as shown.

To effect the alternate pressurizing and exhausting of the region to the right of the driving piston 12 there is provided a valve-control device 17. The valve-control device 17, as shown more clearly in FIGS. 2 and 5, includes an exhaust valve 13, a valve stem 19 and an actuating piston 20 fixedly secured together as a unit, and operable by the pressurizing of the space 21 below the actuating piston 20. FIG. 2 more clearly shows a fluid connection 22 from the closing pilot valve 23, which connects with a bypassing channel 24 having a relatively restricted upper bleeder portion 25.

In more detail, the valve-control device 17 comprises a valve cap 17a, a valve body 17b and a lower valve cover 17c. The valve cap 17a has an exhausting aperture 17d provided therethrough, which is controlled by the operation of the exhaust valve 18.

The valve body 17b is provided with an axial bypassing bore or channel 24 having the restricting portion 25. Additionally, there is provided a first enlarged space or valve control chamber 36 and a second enlarged space 37 communicating with the exhaust aperture 17d and with a control port 38, the latter communicating with the interior 28 of the driving cylinder 13.

As mentioned hereinbefore, there is reciprocally movable interiorly of the valve body 17b the piston-actuated exhaust valve 18 having as a unitary portion thereof a valve stem 19 having an intermediate piston portion 39. As shown, O-rings 4t}, 41 are provided to prevent fluid escape. Carried with the exhaust valve 18 is a sealing gasket 42, which seals against a sealing portion 172 of the valve cap 171: in the pressurized condition of the control valve 17, as shown in FIG. 2 of the drawings.

As shown in FIG. 2, the lower end of the valve stem 19 has fixedly secured thereto the actuating piston 20 operable within an operating cylinder 43 defined by the aforesaid first enlarged space 36.

A control pressure connection 44 enters the space 21 below the actuating piston 20. The pressure condition within the restricted. portion 17] of the axial bore 17g is constantly maintained by a permanent pressure connection 45 from a high-pressure tank HP1.

Carried with the valve stem 19 is a sealing gasket 46, which seals against a sealing portion 47 of the restricted opening 17 in the exhausted condition of the control valve 17, as shown in FIG. of the drawings. The by passing channel 25 is of relatively small bore and parallels the axial bore 17g and has an inlet port 48 associated therewith. A three-way opening valve 26 is associated with the inlet port 49 leading to the space 21 below the actuating piston 20.

To measure the current passing through the interrupter 1 for relaying functions, a plurality of current transformers CT1, GT2, etc., may be utilized encircling the casing 4 on opposite sides of the clamping portion 3a of the upstanding frame support 3. The present interrupter retains the advantage of maintaining the circuit transformer C'Il at ground potential. One of these current transformers CT1, for example, may be usedv to actuate an overload or protective relay OL, as shown in FIG. 1.

To effect opening of the circuit interrupter 1, the coil 50 of the opening pilot valve 26 is energized. This may be obtained by momentarily pressing a trip button 51, or by the actuation of the overload relay OL closing the contacts 0L1 thereof as a result of excessive current flow through the current transformer CTll. This momentarily transmits high pressure from a high-pressure source of fluid HP2 into the space 21 below the actuating piston 21) forcing the latter upwardly to open the exhausting valve 18 and sealing the lower sealing gasket 46 against the valve seat 47 of the valve body 17b, as shown in FIG. 5. Since the volume of the space 21 is relatively small, and the actuating area of piston 20 is large, only a very small build-up of pressure in the space 21 is required to start the exhausting operation of the valve 18. As mentioned hereinbefore, only a momentary application of pressure from the opening switch 51 is required. Inasmuch'a-s the area N, exposed to the constant'high pressure within the axial bore 17 is greater than the area m of the sealing gasket 46 exposed to the same pressure in the exhausted condition, as shown in FIG. 5, pneumatic latching is thereby achieved in the exhausted condition of the control valve 17.

When the exhaust valve 18 has been moved upwardly to the position shown in FIG. 5, fluid pressure, such as air pressure at a pressure of 150 lbs. per sq. in., is exhausted from the space 28, through exhaust port 28 and out exhaust opening 17d of the control valve 17. This will enable the high-pressure gas within the space 54 within casing 4 to act through openings 35 and on the left-hand face 120 of the piston 12 forcing the latter to the right, as viewed in FIG. 1. Such gas is preferably, a highly efficient arc-extinguishing gas, such as sulfurhexafiuoride gas (SP at say, for example, a pressure of 60 p.s.i.g. This opening movement of the driving piston 12 to the right will correspondingly cause rightward movement of the fluid-driving piston 11a within the fluid cylinder 29 and thereby compress fiuid within the space to force such compressed fluid such, for example, as SP gas out through openings 30 and through the orifice 31 of a nozzle, or orifice structure 32 causing extinction of the established are between contacts 6 and 9.

To effect a closing operation of t-heicircuit interrupter 1, the coil 34, associated with the closing pilot valve 23, is energized by pressing closing contacts 23a to thereby effect a momentary pressurized condition through the pipe 22 and inlet port 48 into the bypassing channel 25. Since the restricted portion of the bypassing channel 25 is of only small dimensions, the exhausting of the pressure is less than the entrance of the pressureinto the space 36 above the actuating piston 20, so that the piston 20 is nevertheless forced downwardly to the piston illustrated in FIG. 2 of the drawings. This action closes the exhaust valve 18 sealing the gasket 42 against the valve seat 17e and permitting high pressure to feed into the operating cylinder 13 of the circuit interrupter 1 through bypassing channel 25 from the high-pressure gas tank HP3. Since the pressure supplied by the high-pressure tank HP3 is greater than the pressure supplied within the space 54 interiorly of the casing means 4, the driving piston 12 will be forced pneumatically toward the left to thereby effect closure of the separable contact means 2 to the closed position as shown in FIG. 1 of the drawings.

Inasmuch as the area M exposed to the operating pressure in greater than the area N exposed to the same pressure, the exhaust valve 18 will remain in the closed position shown in FIG. 2. Thus, pneumatic latching is thereby achieved in the pressurized condition of the control valve 17, as shown in FIG. 2.

The control valve 17 has the particular advantage of remaining in its pressurized or exhausted condition without any mechanical latches due to the pressurized condition of the axial bore 17g and the particular arrangement of the component parts. The result is extremely high-speed opening and closing operations of the circuitinterrupting device 1. From the foregoing, it will be apparent that there is provided pneumatic latching, in the pneumatic operating mechanism thus eliminating the need for delicate and troublesome adjustments of mechanical latches. Pneumatic seal-in on the cylinderpressurizing operation is obtained since momentary application of pressure from the closing pilot valve 23 will cause the valve device 17 to complete its closing operation and seal-in with the cylinder 13 remaining pressurized. This eliminates the need for seal-in contacts in the associated electrical control circuit.

A very important characteristic of the control valve 17 particularly as applied to circuit-breaker operation, is the pneumatic trip-free operation, WhlChlS obtained since pressure from the cylinder exhausting opening pilot valve 26 will drive the exhaust valve '18 open, and ex haust the operating cylinder 13 regardless of the energization of the cylinder pressurizing closing pilot valve 23. This eliminates the need for mechanical trip-free linkages to assure circuit-breaker tripping even though the closing coil is energized.

Morespecifically, with the exhaust valve 18 closed, as shown in FIG. 2, and with both pilot valves 23, 26 energized, there will be an upward unbalanced opening force tending to unseat valve 18 equal to the pressure in space 27 times the entire opening area of exhaust outlet 17d. Once the exhaust valve 18 has opened the exhaust opening 17d slightly, the pressure will drop in the space 37. Now the forces acting on the intermediate piston portion 39 will be unbalanced, since high pressure exists below piston 39 and t'he'pressure is dropping above piston 39 in the space 37. In addition, at this time there is an additional upward exhausting force equal to the stem area'X times the high pressure below the actuating piston 20 in the'volume 21. And, moreover, to supplement this force, there will be the differential force on the exhaust valve 18itself, this force, however, dropping as the valve 18 moves to its upper end exhausting position, as shown in FIG; 5.

The pneumatic control circuit set forth in FIG. 2 of the drawings includes an anti-pump control scheme, which. is set forth and claimed in my concurrently filed United States patent application, Ser. No. 401,298. As shown, the coil and contacts designated as Z and Z1 indicate a standard relay, or contactor so connected that it will pick up on a momentary contact of the controlswitch tripping contact 5 1 and maintain itself and the trip coil 50 in an energized condition until the circuit is broken by a series-connected auxiliary switch contact. Such a contact is designated as an in this scheme, and is a pressure-operated switch actuated by pressure from a connection 60 between the cylinder-pressurizing pilot valve 23 and the bleed hole 25. This contact will, therefore, be closed at all times when the operating cylinder 13 is pressurized, that is in the circuit-breaker closed position, and also at all times when the closing coil 34 is energized, thus applying pressure to the control valve 17 in an attempt to pressurize the cylinder 13. The reference letters R and G design-ate conventional red and green indicating lights; and contacts a and b are auxiliary switch contacts used in the conventional sense to indicate ,the closed or open-circuit positions of the circuit breaker 1.

An important feature of the control circuit, as illustrated in FIG. 2, is the use of the aa contact in the trip coil, or Z coil circuit 61 to provide non-pumping operation with a very simple control circuit, thus eliminating the need for the conventional X and Y relays, which are used inconventional control schemes of the prior art.

The closing coil 34 can be energized at any time by closing the control switch contact 23a. Since the pneumatic latching device 17 seals in pneumatically, only a monentary contact of the closing button 23a is required to assure completion of the closing operation of the internupter 1.

Closing the control switch contact 5 1 energizes the Z coil provided the aa contact is closed, indicating either that the circuit breaker 1 is closed, or the closing valve 23 is energized in an attempt to close the circuit breaker 1. Energizing the Z coil closes the Z1 contacts, thus sealing the Z relay in. In the illustrated control circuit the trip coil 50 is energized simultaneously with the Z coil. A momentary contact of the control switch 51 or a tripping relay contact 0L1 energizes the Z coil and trip coil 50 which remain energized until the an contact opens, thus assuring completion of the tripping operation.

If both closing and tripping contacts 23a, 51 are closed at the same time, the trip circuit 61 will be energized through the nu contact, and Will remain energized until 'gized, and the circuit breaker will open and remain open until the closing switch 23a is opened and again closed. Therefore, positive tripping is assured regardless of the closing switch position; and pumping (alternate closing and opening of the circuit breaker 1) cannot occur.

As shown in FIG. 1, the high-pressure tanks, tripping and closing pivot valves, non-pumping relay and the electrical supply 63, 64 may be housed in a grounded metallic mechanism housing 65 supported on the upstanding frame support 3 with the pneumatic lines 22, 44, and 45 composed of a suitable insulating material, such as plastic or ceramic tubing to hold the voltage.

By'way of recapitulation, during the opening operation the exhaust valve 18 of the control device 17 is opened by the application of pressure below the actuating piston 20. This will force the exhaust valve 18 upwardly to exhaust the region 28 to the right-hand side of the driving piston 12 to thereby effect rightward opening move ment of the movable contact structure 7. An arc will be drawn between the separated contact structure 2, and the compression of fluid, such as SP gas, within the opera-ting cylinder 29 will force fluid through apertures 30 associated with the contact structure 2 and through the orifice 31 of a nozzle 32 and into the arc to effect the extinction thereof. In the open-circuit position of the interrupter, not shown, the fluid Will be exhausted from the rear of the driving piston 12, and the pressure within the housing 4 will act upon the left-hand face of the driving piston 12 and insure that the contact structure 7 will remain open. As set forth in United States Patent 3,185,180, issued May 25, 1965 to William A Fish, Jr. and Charles B. Wolf and assigned to the assignee of the present application, the pneumatic control device 17 has the automatic feature of latching into the open or closed positions with no mechanical latches necessary.

The insulating casing may be a unitary elongated piece, or, as illustrated in FIG. 4, the casing may be of a split construction, and have a grounded ring 33 associated therewith. In this modified arrangement differential relay operation is quite convenient and may be used to distinguish between internal and external fault conditions, as desired.

To effect the closing operation of the interrupter, energization of the closing solenoid 34 by pressing the closing button 2311 will force pressure into the valve device 17 through the pressure line 22 and will effect closing of the exhaust valve 18 and a consequent pressurizing of the region 28 to the right-hand side of the driving piston 12. This will close the contact structure 7 and will position the parts in the closed position, as shown in FIG. 1.

Although for diagrammatic illustration in FIG. 2 the high-pressure tanks HPl, HPZ and HP3 have been indicated as separate high-pressure reservoir tanks. In fact, the three tanks could, of course, be combined as one tank disposed within the mechanism housing 64 of FIG. 1. As mentioned hereinbefore, the operating gas in the high pressure tanks is preferably compressed air, at say a pressure of p.s.i.g., for example. As is obvious, this pressure merely needs to be higher than the pressure of the gas within casing 4, which is assumed to be 60 p.s.i.g.

From the foregoing description it will be apparent that there is provided an improved puffer-type fluid-blast circuit-interrupting device 1 of simple construction and utilizing a minimum number of control lines. Additionally, the circuit-interrupting arrangement 1 is readily adaptable to a fluid-control valve 17 of the type set forth in United States Patent 3,185,180, and no mechanical latches need be provided.

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 as my invention:

LA fluid-blast circuit interrupter of the putter type pneumatically latched in both the open and closed-circuit positions including means defining an elongated cylindrical insulating casing means With the opposite ends thereof open, grounded supporting means for fixedly supporting said elongated insulating casing means horizontally adjacent the mid-portion thereof an adequate distance above ground potential, an end terminal member closing one open end of the insulating casing means and having a stationary contact post secured thereto, said stationary contact post secured thereto, said stationary contact post having a fixed stationary contact secured to the inner extremity thereof and disposed an operating cylinder and a driving piston reciprocably movable therein, means connecting said driving piston with said one part so as to cause the opening and closing movement of said movable contact, means constantly exposing one face of said driving piston to the pressure within said pressurized casing means, and exhaust valve means pneumatically latched in both the open and closed positions carried by said unitary removable structure for alternately pressurizing or exhausting the other face of the driving piston within the operating cylinder.

2. The fluid-blast circuit interrupter of claim 1, wherein said exhaust valve means includes a valve control chamber (36) constantly pressurized with compressed air and a pair of movable valve elements (18, 46) connected together to move as a unit, and differential-area piston means (39, 20) exposed to the pressure of said valve control chamber (36) for actuating said valve elements.

3. The fluid-blast circuit interrupter according to claim 2, wherein the exhaust-valve means includes a bypassing channel (24) with a restricted portion (25) leading to an inlet port (48) of a two-way closing controlvalve (23).

References Cited by the Examiner UNETED STATES PATENTS 3,043,940 7/1962 Leeds 200-148 3,060,294 10/1962 Leeds 200-448 3,163,737 12/1964 Gonek et al. 200-148 3,171,937 3/1965 McKeough 200-148 ROBERT K. SCHAEFER, Primary Examiner.

R. S. MACON, Examiner.

Claims (1)

1. A FLUID-BLAST CIRCUIT INTERRUPTER OF THE PUFFER TYPE PNEUMATICALLY LATCHED IN BOTH THE OPEN AND CLOSED-CIRCUIT POSITIONS INCLUDING MEANS DEFINING AN ELONGATED CYLINDRICAL INSULATING CASING MEANS WITH THE OPPOSITE ENDS THEREOF OPEN, GROUNDED SUPPORTING MEANS FOR FIXEDLY SUPPORTING SAID ELONGATED INSULATING CASING MEANS HORIZONTALLY ADJACENT THE MID-PORTION THEREOF AN ADAQUATE DISTANCE ABOVE GROUND POTENTIAL, AN END TERMINAL MEMBER CLOSING ONE OPEN END OF THE INSULATING CASING MEANS AND HAVING A STATIONARY CONTACT POST SECURED THERETO, SAID STATIONARY CONTACT POST SECURED THERETO, SAID STATIONARY CONTACT POST HAVING A FIXED STATIONARY CONTACT SECURED TO THE INNER EXTREMITY THEREOF AND DISPOSED ADJACENT THE MID-PORTION OF SAID CASING MEANS, A MOVABLE UNITARY MOVABLE CONTACT AND FLUID-DRIVING STRUCTURE CLOSING THE OTHER OPEN END OF THE INSULATING CASING AND HAVING A TERMINAL PORTION, MEANS PRESSURIZING SAID CASING MEANS, SAID REMOVABLE UNITARY STRUCTURE INCLUDING FLUID-DRIVING PISTON MEANS INCLUDING AN OPERATING CYLINDER AND A PISTON RELATIVELY MOVABLE WITH RESPECT TO EACH OTHER AND CONSTITUTING A PAIR OF RELATIVELY MOVABLE PARTS, A MOVABLE CONTACT COOPERABLE WITH SAID STATIONARY CONTACT TO ESTABLISH AN ARC, MEANS SECURING SAID MOBABLE CONTACT TO ONE OF SAID PARTS SO AS TO MOVE THEREWITH, SAID REMOVABLE UNITARY STRUCTURE ADDITIONALLY INCLUDING AN OPERATING CYLINDER AND A DRIVIANG PISTON RECIPROCABLY MOVABLE THEREIN, MEANS CONNECTING SAID DRIVING PISTON WITH SAID ONE PART SO AS TO CAUSE THE OPENING SAND CLOSING MOVEMENT OF SAID MOVABLE CONTACT, MEANS CONSTANTLY EXPOSING ONE FACE OF SAID DRIVING PISTON TO THE PRESSURE WITHIN SAID PRESSURIZED CASING MENS, AND EXHAUST VALVE MEANS PNEUMATICALLY LATCHED IN BOTH THE OPEN AND CLOSED POSITIONS CARRIED BY SID UNITARY REMOVABLE STRUCTURE FOR ALTERNATELY PRESSURIZING OR EXHAUSTING THE OTHER FACE OF THE DRIVING PISTON WITHIN THE OPERATING CYLINDER.

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