US3310648A - Gas blast circuit breaker with nozzle formed contacts and control for associated gasoutlet valves - Google Patents

Description

March 21, 1967 P. BALTENSPERGER 3,310,648

GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTS AND CONTROL FOR ASSOCIATED GAS OUTLET VALVES Filed Aug. 15, 1964 2 Sheets-Sheet 1 PauL Balfnsperger 13% 1% Y9 JPWIW ATTORNEYS P. BALTENSPERGER 3,310,648

March 21, 1967 GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTS AND CONTROL FOR ASSOCIATED GAS OUTLET VALVES Filed Aug. 13, 1964 2 Sheets-Sheet 2 I&W/

INVENTOR Pcw L Baliensperge r /fiw iigguvgpwwaw ATTORNEY S United States Patent 3,310,648 GAS BLAST CIRCUIT BREAKER WITH NOZZLE FORMED CONTACTS AND CONTROL FOR AS- SOCIATED GAS OUTLET VALVES Paul Baltensperger, Wurenlos, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland, a joint-stock comp-any Filed Aug. 13, 1964, Ser. No. 389,345 Claims priority, application Switzerland, Sept. 20, 1963, 11,609/63 7 Claims. (Cl. 200148) This invention relates to a preferably multi-break gas blast circuit breaker comprising twin-nozzle-contact interrupter chambers which are at high tension and pres surized by a compressed gas in both make and break positions, each nozzle contact being associated with an outlet valve for the generation of air blast for controlling the arc and one of said outlet valves being operable by actuator means at earth potential.

Air blast circuit breakers are known in which the interrupter unit comprises two nozzle contacts. The pair of nozzle contacts in this circuit breaker is located inside an interrupter chamber which remains permanently under gas pressure. When the circuit breaker is tripped the nozzle contacts are separated by either one or both being withdrawn by appropriate actuating means and the resultant arc is controlled by an air blast. For this purpose each of the nozzle contacts is associated with an outlet valve which remains closed so long as the circuit breaker is closed, but which opens for a brief period when the nozzle contacts separate, permitting the compressed gas in the interrupter chamber to escape through the interior of the nozzle contacts, thereby creating an air blast for controlling the are within the contact gap. The outlet valves may be pneumatically or hydraulically controlled in such manner that one of the outlet valves is operable by actuator means which are at earth potential, whereas, the other outlet valve is pneumatically or hydraulically operable through an insulating tube. When the circuit breaker is open, the insulating tube is at high potential and this introduces the familiar problems involved in controlling the creep currents. These are particularly difiicult to control in circuit breakers for rated voltages across each break which are relatively high, for example, in the order of llO kv. and more. 7

The object of the present invention is to provide a solution permitting the said difficulties to be overcome. According to the invention, this is achieved by operating the other outlet valve by an insulating transmission member, which is associated inside the interrupter chamber, with actuating means and which only briefly makes contact with the controlled outlet valve, being otherwise separated therefrom by a compressed gas gap.

An embodiment of the proposed circuit breaker will be described in greater detail by reference to the accompanying drawings in which FIG. 1 is a part sectional view of one interrupter chamber of a twin-break pneumatic air blast circuit breaker according to the invention, whereas FIG. 2 is a section taken on the line I-I in FIG. 1, and

FIG. 3 is a section taken on the line II-II in FIG. 2.

FIG. 1 shows a hollow post type insulator 1 which supports the circuit breaker casing 2. Thelatter comprises a central portion 3 which is firmly connected on each side to an interrupter unit 4 containing a compressed gas. 5 is a movable nozzle contact formed with a piston portion 5a working in a cylindrical extension 3a of the central part 3 of the casing. The current is taken through a sliding tulip connector 6 screwed to extension 3a by a cover plate 7. 8 is a spring interposed between .vided with openings 45a.

3,310,648 Patented Mar. 21, 1967 piston 5a and the interior of extension 3a. The center portion of the casing is surmounted by a valve box 9 closed at the top by a cover 10. An insulating push rod 11 which axially traverses the post insulator 1 extends upwards through the center portion 3 of the casing and at the top carries a hollow valve stem 12 with openings 12a. This hollow valve stem 12 carries valve discs 13 and 14. Valve disc 13 cooperates with two seals 15 and 16, whereas, valve disc 14 similarly cooperates with two seals 17 and 18. The seals 15 and 1-8 are countersunk in plates provided with openings 19 and 20 respectively. The interior of the valve box 9 communicates with the outside through holes 21. An air pipe 22 leads to the piston chamber 24 on the left of piston 5a, and a second air pipe 23 leads to the chamber 25 on the right of the piston. A channel 26 provides a. communication between pipe 22 and a cylinder 27 containing a piston 28. Piston 28 contains an opening 29 connecting channel 26 with chamber 30. This chamber is closed by a cover 31 which slidably guides an insulating push rod 32 firmly secured to piston 28. 33 is a spring interposed between cover 31 and piston 28. The left hand end of the insulating push rod 32 has a widened head 32a. Secured to the left hand end of interrupter chamber 2 is an insulating bushing 34 inside which a hollow conductor 35 is supported by an insulating sleeve 36. Hollow conductor 35 is rigidly attached to an intermediate member 37. The latter carries a cylinder 38 containing a sleeveshaped valve element 39 which is slidably guided in the cylinder by its piston 39a. The latter is traversed by a hole 3911 which connects the two valve chambers 40 and 41. Located in chamber 41 is a spring 42. This is interposed between piston 39a and the intermediate member 37. The interior of the hollow conductor 35 is in permanent communication with the outside atmosphere through an opening at its left hand end not especially shown in the drawing. Attached to cylinder 38 is a stationary nozzle contact 43. The left hand end of this nozzle contact is widened and encloses a valve-seat 43b which is supported by web members 43a and which is provided with an inserted seal 44. Cylinder 38 also supports the valve casing 45 of a valve member 46. The latter is formed with a piston 46a which bears against one end of a spring 47 of which the other end is supported by the valve casing cover 48. An opening 48a in the cover provides permanent communication between chamber 49 and the interior of the interrupter chamber 2. The right handend of valve member 46 carries a tappet 50 projecting from valve casing 45 which is also pro- Chamber 51 communicates on the one hand through channel 52 with chamber 40 and on the other hand through gap 53 with chamber 54. From gap 53 an air pipe 55 leads to the interior of the intermediate member 37. 56 is a seating seal cooperating with valve member 46 in valve casing 45. The actuating gear which is at earth potential is shown at the bottom end of push rod 11. This comprises a cylinder 57 slidably containing a piston 58 to which push rod 11 is attached. The two interrupter chambers 2 are completely symmetrical so that a representation in the drawing of the right hand half of the casing is not considered necessary. The interrupter casing is filled with compressed gas through the hollow post insulator 1, the openings 3b in the central portion of the casing ensuring that both halves of the casing are equally filled. The two chambers 60 in the center portion 3 are in communication through a chamber 60a as will be readily seen by reference to FIGS. 2 and 3. The same reference numbers are used for like parts in FIG. 2 as in FIG. 1, FIG. 2 being a part section taken on the line I-I in FIG. 1 through the center portion 3 of the casing. FIG. 2 further shows a cylindrical casing 61 which is firmly inserted into the center portion 3 and which contains a valve member 62. A valve closing spring 63 is interposed between parts 61 and 62. The valve member 62 cooperates with a sealing disc 64 inserted in the center portion 3. Valve casing 9 is connected on the one hand by air pipe 65 to chamber 66, a throttling constriction 67 being provided at the point of entry into chamber 66, and on the other hand by an air pipe 68 to chamber 69. FIG. 3 is a view from below of a section taken on the line II-II in FIG. 2. In this drawing parts corresponding to those shown in FIGS. 1 and 2 are again identified by the same reference numbers.

The described arrangement functions as follows:

For operating the circuit breaker, compressed gas is admitted through admission pipe 59 into the chamber above piston 58 in cylinder 57, causing the piston to descend. The piston simultaneously withdraws the insulating push rod 11 together with the hollow valve stem 12, so that both valve discs 13 and 14 are moved downwards until they seat on the valve seals 16 and 18 respectively. Consequently, chamber 25 is now placed into communication with the outside atmosphere through pipe 23 and holes 21 and at the same time chamber 24 is filled through pipe 22 with compressed air from the interrupter chamber 2 and the post insulator 1 entering through openings 12a, the hollow valve stem 12 and openings 19. The effect of the compressed gas in chamber 24 is to displace piston a and hence, the movable nozzle contact 5 against the resistance of spring 8 into circuit breaking position. At substantially the same time, compressed gas is also applied through channel 26 to the right hand face of piston 28, forcing the same together with the insulating push rod 32 to the left against the resistance of spring 33. The head 32a of the insulating push rod strikes tappet 50 and pushes valve member 46 to the left, thereby admitting compressed gas through the holes 45a and channel 52 into chamber 40. Piston 39a and hence valve member 39 are therefore displaced to the left against the resistance of spring 42 and valve member 39 is lifted off its seal 44. The are which now strikes between the separating nozzle contacts 5 and 43 is exposed to the blast of the gas entering the fixed nozzle 43 and escaping to the outside air through the interior of parts 43, 39 and 35. At the same time the interior of nozzle contact 5 is likewise placed into communication with the outside air, so that the arc is exposed to a double blast. The chambers 60 with which the interior of the two valve nozzles 5 communicate are exhausted because the downward displacement of the valve discs 13 and 14 has caused pipe 65 (FIG. 2) to fill with compressed gas and pipe 68 to be placed into communication with the outside. Owing to the presence of the throttling constriction 67 at the end of pipe 65 chamber 69 can at once exhaust through pipe 63, Whereas, chamber 66 is only gradually filled. Consequently, the rising pressure in chambers 60, 60a lifts valve member 62 off its seal 64, permitting compressed gas to escape from chambers 60, 60a to the outside. As will be understood from FIGS. 2 and 3 the outlet valve (62, 64) is common to both the central nozzle contacts 5 of the twin break interrupter gear. At the end of a given period of time which is sufficient for the arc to be safely extinguished, the blast in the open circuit breaker gap (5, 43) ceases. This is due to the fact that chamber 66 has meanwhile been filled with compressed gas through constriction 67 sufficiently for returning valve member 62 into the position shown in FIGS. 2 and 3 with the assistance of the valve closing spring 63. chamber 30 (FIG. 1) has likewise meanwhile sufiiciently filled with compressed gas through hole 29 in piston 28 to permit the power of spring 33 to restore piston 28 and hence, the insulating push rod 32 to the right. Tappet 50 is thus released and spring 47 can push valve member 46 back to the right into contact with its seating seal 56.

On the other hand 4 Chamber 40 can therefore exhaust through channel 52, gap 53, pipe 55 and the interior of parts 37 and 35 to the outside air, and spring 42, assisted by the compressed gas which is able gradually to enter chamber 41 through aperture 3% in piston 39a, is thus able to restore valve member 39 into the illustrated position. When the circuit breaker is stationary in the break position there is therefore no contact between the insulating push rod 32, 32a and the tappet 50 which is at opposite potential. The intervening gap is filled with compressed gas and prevents current creep along the insulating push rod 32.

For closing the air blast circuit breaker, the chamber above piston 58 in cylinder 57 is exhausted through pipe 59. The compressed gas acting on the underside of valve disc 14 through opening 20 can therefore raise valve disc 14 and hence, parts 58, 11, 12 and 13 into the illustrated positions. Chamber 24 exhausts through pipe 22 and chamber 25 refills with compressed gas through pipe 23. Piston 5a and hence nozzle contact 5, assisted by spring 8, are therefore returned into the make, i.e., the closed contact position shown in the drawing. During this operation the insulating push rod 32 remains stationary. However, chamber 30 exhausts through aperture 29', channel 26 and pipe 22 in readiness for a repeated operation of the circuit breaker.

Outlet valve 62, 64 (FIGS. 2 and 3) remains closed since chamber 69 fills with compressed gas through pipe 68 more quickly than chamber 66 can exhaust through constriction 67 and pipe 65.

I claim:

1. In an electrical circuit breaker of the gas blast type, the combination comprising a casing forming therein an interruption chamber which is gas-pressurized and at a high potential, a pair of nozzle type contact members located in said interruption chamber, a normally closed outlet valve individual to and which serves when opened to place the interior of each said nozzle contact member in communication with the open air exteriorly of said casing, first actuating means at earth potential for actuating one of said contact members to effect its disengagement from the other contact member and to simultaneously open said outlet valve correlated to said actuated contact member, and said second actuating means for operating the other outlet valve correlated to said other contact member to its open position upon disengagement of said contact members, said second actuating means including a driving member of insulating material and a member driven thereby whose movement controls opening and closing of said other outlet valve, said driving and driven members being located in said interruption chamber and being normally maintained in spaced rela tion to thereby establish a gas-pressurized insulating gap therebetween, and means controlling movement of said driving member by operation of said first actuating means to effect a brief driving engagement as between said driv-' ing and driven members thereby to effect a brief opening of said other outlet valve.

2. An electrical circuit breaker as defined in claim 1 and which further includes means mounting said outlet valve correlated to said second actuating means interiorly of said interruption chamber, and which further includes an insulating bushing through which are conducted the exhaust gases passing through said outlet valve.

3. An electrical circuit breaker as defined in claim 1 wherein said driving member of said second actuating means is constituted by a push rod made from insulating material and which is mounted for movement longitudinally of itself against the action of a biasing spring to engage said driven member which is constituted by a tappet on said other outlet valve.

4. An electrical circuit breaker as defined in claim 1 wherein said other outlet valve correlated to said second actuating means comprises a main valve cylinder mounted in said interruption chamber, a main valve piston within said valve cylinder and which is slidable against the action of a biasing spring to open said outlet valve, and a servo valve for supplying pressurized gas into said main valve cylinder, said servo valve including a cylinder and control piston therein, and said control piston of said servo valve being connected to said driven member of said second actuating means.

5. An electrical circuit breaker as defined in claim 4 wherein said main valve cylinder is located concentric with and adjacent to the correlated nozzle contact member and said main valve piston is hollow and serves to pass through it the gases discharged through said nozzle contact member.

6. An electrical circuit breaker as defined in claim 1 wherein said means controlling movement of said driving member of said second actuating means is constituted by a spring biased piston located within a cylinder disposed within said interruption chamber, pressurized gas being admitted into said cylinder simultaneously with admission of pressurized gas into a cylinder to actuate a piston connected to one of said nozzle contact members and which constitutes the said actuating means therefor.

7. An electrical circuit breaker as defined in claim 1 wherein said outlet valve correlated to said second actuating means comprises a main valve cylinder mounted in said interruption chamber, a main valve piston Within said valve cylinder and which is slidable against the action of a biasing spring to open said outlet valve, and a servo valve for supplying pressurized gas into said main valve cylinder, said servo valve including a cylinder and control piston therein also within said interruption chamber, said control piston of said servo valve being connected to said driven member of said second actuating means, said means controlling movement of said driving member of said second actuating means including a control cylinder likewise mounted in said interruption chamber and a spring biased piston located Within said control cylinder and attached to said driving member, pressurized gas being admitted into said control cylinder simultaneously with admission of pressurized gas into a cylinder to actuate a piston connected to one of said nozzle contact members and which constitutes the said actuating means therefor.

Claims (1)

1. IN AN ELECTRICAL CIRCUIT BREAKER OF THE GAS BLAST TYPE, THE COMBINATION COMPRISING A CASING FORMING THEREIN AN INTERRUPTION CHAMBER WHICH IS GAS-PRESSURIZED AND AT A HIGH POTENTIAL, A PAIR OF NOZZLE TYPE CONTACT MEMBERS LOCATED IN SAID INTERRUPTION CHAMBER, A NORMALLY CLOSED OUTLET VALVE INDIVIDUAL TO AND WHICH SERVES WHEN OPENED TO PLACE THE INTERIOR OF EACH SAID NOZZLE CONTACT MEMBER IN COMMUNICATION WITH THE OPEN AIR EXTERIORLY OF SAID CASING, FIRST ACTUATING MEANS AT EARTH POTENTIAL FOR ACTUATING ONE OF SAID CONTACT MEMBERS TO EFFECT ITS DISENGAGEMENT FROM THE OTHER CONTACT MEMBER AND TO SIMULTANEOUSLY OPEN SAID OUTLET VALVE CORRELATED TO SAID ACTUATED CONTACT MEMBER, AND SAID SECOND ACTUATING MEANS FOR OPERATING THE OTHER OUTLET VALVE CORRELATED TO SAID OTHER CONTACT MEMBER TO ITS OPEN POSITION UPON DISENGAGEMENT OF SAID CONTACT MEMBERS, SAID SECOND ACTUATING MEANS INCLUDING A DRIVING MEMBER OF INSULATING MATERIAL AND A MEMBER DRIVEN THEREBY WHOSE MOVEMENT CONTROLS OPENING AND CLOSING OF SAID OTHER OUTLET VALVE, SAID DRIVING AND DRIVEN MEMBERS BEING LOCATED IN SAID INTERRUPTION CHAMBER AND BEING NORMALLY MAINTAINED IN SPACED RELATION TO THEREBY ESTABLISH A GAS-PRESSURIZED INSULATING GAP THEREBETWEEN, AND MEANS CONTROLLING MOVEMENT OF SAID DRIVING MEMBER BY OPERATION OF SAID FIRST ACTUATING MEANS TO EFFECT A BRIEF DRIVING ENGAGEMENT AS BETWEEN SAID DRIVING AND DRIVEN MEMBERS THEREBY TO EFFECT A BRIEF OPENING OF SAID OTHER OUTLET VALVE.

Images