US3240910A

US3240910A - Gas blast circuit breaker with stationary spaced tubular contacts and piston actuated contact bridge including blast valve actuated thereby

Info

Publication number: US3240910A
Application number: US291765A
Authority: US
Inventors: Floessel Dieter
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1962-07-05
Filing date: 1963-07-01
Publication date: 1966-03-15
Anticipated expiration: 1983-03-15
Also published as: BE634445A; DE1207990B; DE1216961B; FR1361732A; CH409059A; GB1010017A; US3334207A; FR86197E; GB974587A

Description

March 15, 1966 D. FLOESSEL 3,240,910

GAS BLAST CIRCUIT BREAKER WITH STATIONARY SPACED TUBULAR CONTACTS AND PISTON ACTUATED CONTACT BRIDGE INCLUDING BLAST VALVE ACTUATED THEREBY Filed July 1, 1965 4' INVENTOR y Dl eier FloesseL (AW-Mk Pedal, ATTORNEY6 United States Patent 3,240,910 GAS BLAST CIRCUIT BREAKER WITH STATIGN- ARY SPACED TUBULAR CONTACTS AND PIS- TUN ACTUATED CONTACT BRIDGE INCLUD- ING BLAST VALVE ACTUATED THEREBY Dieter Floessel, Fislisbacli, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie, Baden, Switzerland, a joint-stock company Filed July 1, 1963, Ser. No. 291,765 Claims priority, application Switzerland, July 5, 1962, 8,097/ 62 4 Claims. (Cl. 200-148) The invention concerns a gasblast circuitbreaker where one or more impulse-operated power switching points are located in switch chambers which are kept continuously under a gas pressure.

With gasblast circuit-breakers it is important that the switching point is already under a gas pressure at the instant when the switching contacts separate, so that the are which occurs at the contacts is already subjected to a powerful gas blast right from the beginning. In one known type of gasblast circuit-breaker, a bridging-over contact actuated by the pressure gas which fio-ws into the switch chamber is caused to slide over a stationary tubular contact in a direction opposite to the direction of motion of the mechanically actuated switching contact. A disadvantage of this arrangement is that the pressure gas has to be supplied to the switch chamber from the outside, so that the breaking time is comparatively long. Moreover the arc is only subjected to a gasblast in one axial direction so that the rupturing capacity is very limited. Another design of gasblast circuit-breaker has also been proposed where the switching point is constructed in the form of a double nozzle, but it also possesses the disadvantage that the pressure gas has to be supplied from the outside to the extinguishing chamber.

The present invention is based on such a circuitbreaker and the object is to provide -a simple solution for a quick-acting and powerful gas blast circuit-breaker which does not have the aforementioned disadvantages of the hitherto known types.

In accordance with the invention it is therefore proposed that each switching point should have two coaxial nozzle tubes spaced a fixed distance apart and through which for the purpose of extinguishing the arc pressure gas flows in opposite directions, and that a movable bridging-over switch piece is provided which connects the two nozzle tubes and on the one hand is indirectly connected to a driving piston subjected to a gas pressure and on the other hand to a valve seat, and that moreover that one of the nozzle tubes is provided with a valve disc which together with the valve seat form the blast valve for the pressure gas. By these means it is possible -according to the invention to subject the are immediately to an intense blast of pressure gas with an optimum arcextinguishing distance between the contacts, so that the number of elements required for this purpose is reduced to a minimum.

The invention is explained in more detail by means of a constructional example shown in the drawing. This illustrates a double switching head for a gasblast circuitbreaker with two load current switching points electrically connected in series.

Reference numeral 1 indicates a hollow insulator to which a middle piece 2 is fixed. On each side of the latter there is a switch chamber casing 3. For the sake of clearness only the left half of the double switching head is shown in the drawing because it is of symmetrical construction. The middle piece 2 is rigidly joined to the cylinder 4 in which the nozzle tube 5 and sleeve 6 are fixed. The bridging-over switch piece 7 consists of ice an essentially tubular assembly of contact laminations 8 which are arranged within the tubular element 9 in the form of a tulip contact and are held by means of leaf springs 10. The right-hand end of the tubular element 9 is provided with an annular piston 11 which is arranged to slide between the parts 4 and 6. The lefthand end of tubular element 9 is constructed in the form of a ring-shaped valve seat 12. The switch chamber casing 3 supports the hollow insulator 13 which by means of flange 14, ring nut 15, and insulating tube 16, is firmly fixed to the casing 3. Moreover, ring nut 15 also serves to fix the nozzle tube 17 which is provided with a collar 17a acting as a valve seat and furnished with an inserted ring-shaped sealing disc 18. Above the middle line, the bridging switch piece 7 is shown in the closed position whilst in the lower half it is in the open position, whereby the are which burns between the nozzle tubes 5 and 17 is indicated by the irregular line 19. The operating chamber 20 in cylinder 4 contains the spring 21. Chamber 20 is connected to control valve 23 by way of channel 22, and the actuating pipe 24 for the valve is located inside of the hollow insulator 1 and leads to the lower part of the circuit-breaker which is not shown in the figure. The inside part of the middle piece 2 communicates by means of the opening 25 with the outside atmosphere, whilst the annular channels 26, 26a provide a communication between the switch chamber casings 3 on the one hand and on the other hand by way of hollow insulator 1 with the pressure gas container in the lower part of the circuit-breaker.

The method of operation of the arrangement described is as follows. In the position shown above the middle line, the bridging switch piece 7 forms a connection between the two nozzle tubes 5, 17 of the power interruption point by means of the contact laminations 8. The current path is thus formed by the

parts

14, 15, 17, 8, 5, 4, 2 and continues along the right half of the doubleswitching head which is not illustrated. The switch chamber casing 3 is constantly under a gas pressure which in the closed position is maintained right up to the blast valve formed by the

parts

12, 18, 17a. The control valve 23 is constructed in such a manner that chamber 20 is also filled with pressure gas. For the opening operation, the control valve 23 receives a pressure impulse from the pipe 24 whereupon control valve 23 connects by way of channel 22 as indicated by the arrow the chamber 20 with the outside air and thus allows the pressure gas to escape. The pressure gas in the casing 3 thus acts only on one side, that is on the left side of the ring piston 11 and moves it against the force of the spring 21 towards the right until it reaches the end position shown in the lower half of the figure. Since at the same time the bridging switch piece 7 is set in motion, the blast valve consisting of the

elements

12, 18, 17a is opened and the arc 19 which occurs between the nozzle tubes 5 and 17 is subjected to a gas blast and extinguished. The pressure gas flows as indicated by the arrows from the casing 3 over the switching point and then through the nozzle 17 towards the left as well as in the opposite direction through the other nozzle tube 5 and opening 25 to the outside. In the constructional form that has been described, the control valve 23 is common to both switching points of the double switching head. The gasblast circuit-breaker can also consist of an assembly of several switch units, each containing a double switching head and connected electrically in series (multiple interruption), whereby in a known manner voltage interruption points are arranged in series with these units for isolating the circuit-breaker when in the open position, so that after they have opened the power interruption points can be closed again. With the selected constructional form this is achieved in that the pressure impulse in the operating pipe 24 of the control valve is removed after the voltage switching points have opened, so that the chamber 20 is filled by way of channel 22 with the pressure gas. Due to the equalization of the pressure on both sides of the actuating piston 11, the latter together with the bridging switch piece '7 is moved into the left-hand end position by the spring 21. The blast valve thus also closes due to the valve seat 12 being pressed against the seal 18, so that the gas blast to the contacts ceases. The pressure gas which escapes from the switch chamber casing 3 when the circuit-breaker opens is replaced, as indicated by the arrows, by gas which is supplied from the pressure gas container by way of the hollow insulator 1 and channel 26. The gasblast circuit-breaker is closed in a known manner by means of the aforementioned voltage switching points which are not shown.

I claim:

1. In a circuit breaker of the gas blast type, the combination comprising a switch chamber the interior of which is gas-pressurized when the breaker is closed, first and second co-axially aligned stationary tubular nozzle loadbreaking contact members located within said gas-pressurized switch chamber and arranged with their nozzle ends in confronting spaced relation, a tubular bridgingover contact member surrounding the first of said tubular nozzle contact members and slidable longitudinally of the same to bridge over and elfect electrical contact with said second tubular nozzle contact member, a driving piston for and forming a part of said bridging-over contact member and which is located at one end thereof, a cylinder surrounding said first tubular contact member and which receives said piston, said cylinder and one side of said piston being open to the interior of said gas-pressurized switch chamber, spring means cooperative with said bridging-over contact member and which exert an axially applied force thereon in the direction to move it into engagement with and surrounding said second tubular contact member when the respective gas pressures within said cylinder and switch chamber are equalized, valve means cooperative with said cylinder and which are operable either to vent said cylinder to atmosphere or to connect the same with a pressurized gas source, venting of said cylinder serving to establish a force differential on the opposite sides of said piston in the direction driving said piston and bridging-over contact member to effect disengagement of the latter from said second tubular contact member, and a gas blast valve structure controlled by movement of said bridging-over contact member for controlling flow of pressurized gas from said switch chamber into and through the nozzles of said tubular contact members, said gas blast valve structure including ring-shaped valve seat and sealing disc members, one of said members of said valve structure being located at the opposite end of said bridging-over contact member and the other being located on and surrounding said second tubular contact member.

2. A circuit breaker of the gas blast type as defined in claim 1 wherein said ring-shaped valve seat is located on said bridging-over contact member and said ring-shaped sealing disc is located on and surrounding said second tubular contact member.

3. A circuit breaker of the gas blast type as defined in claim 1 wherein said spring means is disposed Within said cylinder.

4. In a circuit breaker of the gas blast type, the combination comprising a switch chamber the interior of which is gas-pressurized when the breaker is closed, first and second co-axially aligned stationary tubular nozzle load-breaking contact members located within said gas pressurized switch chamber and arranged with their nozzle ends in confronting spaced relation, a tubular bridgingover contact member surrounding the first of said tubular nozzle contact members and slidable longitudinally of the same to bridge over and effect electrical contact with said second tubular nozzle contact member, a driving piston for and forming a part of said bridging-over contact member and which is located at one end thereof, a cylinder surrounding said first tubular contact member and which receives said piston, said cylinder and one side of said piston being open to the interior of said gas-pressurized switch chamber, spring means located within said cylinder and which bear against the opposite side of said piston, said spring means exerting an axially applied force on said piston in the direction to move said bridging-over contact member into engagement with and surrounding said second tubular contact member when the respective gas pressures within said cylinder and switch chamber are equalized, valve means cooperative with said cylinder and which are operable either to vent said cylinder to atmosphere or to connect the same with a pressurized gas source, venting of said cylinder serving to establish a force dilferential on the opposite sides of said piston in the direction driving said piston and bridging-over contact member to effect disengagement of the latter from said second tubular contact member, and a gas blast valve structure controlled by movement of said bridging-over contact member for controlling flow of pressurized gas from said switch chamber into and through the nozzles of said tubular contact members, said gas blast valve structure including a ring-shaped valve seat formed at the opposite end of said bridging-over contact member and a ring-shaped sealing disc on and surrounding said second tubular contact member.

References Cited by the Examiner UNITED STATES PATENTS 4/1953 Schneider 200-148 7/1962 Leeds 200l48

Claims

1. IN A CIRCUIT BREAKER OF THE GAS BLAST TYPE, THE COMBINATION COMPRISING A SWITCH CHAMBER THE INTERIOR OF WHICH IS GAS-PRESSURIZED WHEN THE BREAKER IS CLOSED, FIRST AND SECOND CO-AXIALLY ALIGNED STATIONARY TUBULAR NOZZLE LOADBREAKING CONTACT MEMBERS LOCATED WITHIN SAID GAS-PRESSURIZED SWITCH CHAMBER AND ARRANGED WITH THEIR NOZZLE ENDS IN CONFRONTING SPACED RELATION, A TUBULAR BRIDGING OVER CONTACT MEMBER SURROUNDING THE FIRST OF SAID TUBULAR NOZZLE CONTACT MEMBERS AND SLIDABLE LONGITUDINALLY OF THE SAME TO BRIDGE OVER AND EFFECT ELECTRICAL CONTACT WITH SAID SECOND TUBULAR NOZZLE CONTACT MEMBER, A DRIVING PISTON FOR AND FORMING APART OF SAID BRIDGING-OVER CONTACT MEMBER AND WHICH IS LOCATED AT ONE END THEREOF, A CYLINDER SURROUNDING SAID FIRST TUBULAR CONTACT MEMBER AND WHICH RECEIVES SAID PISTON, SAID CYLINDER AND ONE SIDE OF SAID PISTON BEING OPEN TO THE INTERIOR OF SAID GAS-PRESSURIZED SWITCH CHAMBER, SPRING MEANS COOPERATIVE WITH SAID BRIDGEING-OVER CONTACT MEMBER AND WHICH EXERT AN AXIALLY APPLIED FORCE THEREON IN THE DIRECTION TO MOVE IT INTO ENGAGEMENT WITH AND SURROUNDING SAID SECOND TUBULAR CONTACT MEMBER WHEN THE RESPECTIVE GAS PRESSURES WITHIN SAID CYLINDER AND SWITCH CHAMBER ARE EQUALIZED, VALVE MEANS COOPERATIVE WITH SAID CYLINDER AND WHICH ARE OPERABLE EITHER TO VENT SAID CYLINDER TO ATMOSPHERE OR TO CONNECT THE SAME WITH A PRESSURIZED GAS SOURCE, VENTING OF SAID CYLINDER SERVING TO ESTABLISH A FORCE DIFFERENTIAL ON THE OPPOSITE SIDES OF SAID PISTON IN THE DIRECTION DRIVING SAID PISTON AND BRIDGING-OVER CONTACT MEMBER TO EFFECT DISENGAGEMENT OF THE LATTER FROM SAID SECOND TUBULAR CONTACT MEMBER, AND A GAS BLAST VALVE STRUCTURE CONTROLLED BY MOVEMENT OF SAID BRIDGING-OVER CONTACT MEMBER FOR CONTROLLING FLOW OF PRESSURIZED GAS FROM SAID SWITCH CHAMBER INTO AND THROUGH THE NOZZLES OF SAID TUBULAR CONTACT MEMBERS, SAID GAS BLAST VALVE STRUCTURE INCLUDING RING-SHAPED VALVE SEAT AND SEALING DISC MEMBERS, ONE OF SAID MEMBERS OF SAID VALVE STRUCTURE BEING LOCATED AT THE OPPOSITE END OF SAID BRIDGING-OVER CONTACT MEMBER AND THE OTHER BEING LOCATED ON AND SURROUNDING SAID SECOND TUBULAR CONTACT MEMBER.