US3206582A

US3206582A - Air-blast circuit breaker with double nozzle

Info

Publication number: US3206582A
Application number: US242481A
Authority: US
Inventors: Jukka A K Jussila
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1961-12-07
Filing date: 1962-12-05
Publication date: 1965-09-14
Anticipated expiration: 1982-09-14
Also published as: DE1169553B; BE625691A; CH389061A

Description

Sept 14, 1965 J. A. K. JusslLA 3,206,582

AIR-BLAST CIRCUIT BREAKER WITH DOUBLE NOZZLE Filed Dec. 5, 1962 Rm ,ma

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United States Patent O 3,206,582 AIR-BLAST CIRCUIT BREAKER WITH DOUBLE N OZZLE Jukka A. K. Jussila, Gebenstof, Switzerland, assignor to Aktiengesellschaft Brown, Boveri & Cie., Baden, Switzerland, a joint-stock company Filed Dec. 5, 1962, Ser. No. 242,481

Claims priority, application Switzerland, Dec. 7, 1961,

14,207/ 61 3 Claims. (Cl. 200--148) The invention concerns lan air-blast circuit breaker with a double nozzle, one of the nozzles acting as the fixed contact element and the other one as the movable contact element. When these circuit breakers are in the open position, the separated contacts are kept under air pressure.

In order to be able to operate such a circuit breaker it is necessary to provide complicated control equipment. It is necessary not only to actuate the contacts but also additional valves which ensure that the contacts are subjected to a blast of compressed `air and that the pressure air remains in the arc extinguishing chamber after interruption has occurred. This necessitates the provision of several control pipes which are supplied with air from the compressed air container where the pressure differs from that in the arc extinguishing chamber.

It is therefore desirable that the control system for such circuit breakers should be simplified. This is achieved in accordance with the invention by arranging an exhaust valve at the rear end of each nozzle, one of these valves being at the same time an operating valve while the other valve is connected to a piston which shuts oit a container which is constantly under pressure.

A constructional example of a circuit breaker according to the invention is illustrated schematically in the accompanying drawing. The circuit breaker is shown in the figure in the position required for the occurrence of the air blast.

Located inside the switch chamber 1 are the two coaxial tubular contacts 2, 3. In the present example contact 2 is stationary and contact 3 is movable. The movable contact 3 is provided with a piston 4 against which a spring 18 exerts a pressure. Piston 4 operates within a cylinder part 6a of a housing and the other part 6b of this housing serves to accommodate spring 18 and functions as a chamber for exhaust valve 6. Reference number 5 indicates the exhaust valve easing of the fixed contact 2 and 6 is the exhaust valve for the movable contact 3. Valve 5 comprises a valve disc 7 land a piston 8 which is joined to the valve disc by means of a spindle 9. Piston 8 is provided with holes 11 which can be closed by a non-return plate 10. Behind the piston there is a chamber 13 in which a certain pressure is maintained. Furthermore, there is an lopening 12 through which air can slowly escape from chamber 13. The control system is indicated by the control element 19 which can be actuated lby way of the control pipe 20. The line 23 indicates a connection to an interlocking `device 21. The locking device 21 for piston 4 serves to maintain it and hence contact member 3 disengaged from contact member 2 for as long as it is desired to maintain the contacts in their disengaged position. Contact member 3 can be released so as to shift to the left by the restoring force built up in compression spring 19 by releasing the locking device from piston 4 with a pressure pulse transmitted over line 23 from the control element 19. This locking device per se is conventional and can be found more particularly described and illustrated in German Patent No. 1,049,954, dated February 5, 1959. Compressed air is supplied by Way of pipe 22 to the switch or extinguishing chamber 1. By numeral 24 is designated an insulating 3,206,582 Patented Sept. 14, 1965 ICC support for the stationary hollow contact 2, the support being clamped between switch chamber 1 and valve housing 5.

In the closed position of the hollow contact members 2, 3 as indicated by the broken line position of contact member 3, valves 6 and 7 will be in their closed positions as indicated by the broken lines. Moreover, the interior of these contact members as well as the housing for valve 6 and housing 5 of valve 7 and the interior of chamber 13 will have been re-iilled with pressure gas from switch chamber 1 flowing into the latter while contacts 2 and 3 were held in a separated condition by locking device 21.

The method of operation for disconnections is as follows:

Exhaus-t valve 6 is opened vby means of control element 19 due to compressed air from control pipe 20 acting yon the element, whereupon compressed air flows from the inside of tubular contacts 2 and 3 to the outside. Piston 4 is, however, still subjected to the full pressure of the compressed air, so that tubular contact 3 is moved against the spring 18 and the contacts separate. Compressed air then flows from the extinguishing chamber into the tubular contacts 2, 3 as indicated by the arrows in the figure. As a result, the arc which has occurred is extinguished. Piston 4 passes beyond the interlocking device 21 which holds the movable contact 3 in a fixed position. On the other hand, there is also a drop in pressure in chamber 15, so that the compressed air in cham ber 13 acts on piston 8. Valve 7 is opened and compressed air can now flow through opening 16. Nonreturn valve 10 closes the openings 11 in piston 8, so that the pressure is rst of all maintained in chamber 13. Air escapes slowly through the opening 12 so that the pressure in chamber 13 decreases somewhat after a certain time. In the meantime valve 6 closes again due to the blast pressure which acts on the valve. Similarly, due to spring 17 and the blast pressure, valve disc 7 is moved towards the left against the somewhat reduced pressure in chamber 13 and closes the exhaust port 16 so that the extinguishing chamber 1 is closed again and can be refilled with compressed air supplied by way of compressed lair pipe 22. This compressed air ensures that the electric strength between contacts 2 and 3 is adequate.

Chamber 13 is refilled with air again which flows through the openings 11 which only open when the pressure in the extinguishing chamber is higher than that in chamber 13.

If the circuit breaker has to be closed, interlocking device 21 is released, whereupon spring 18 causes piston 4 and movable contact 3 to move towards fixed contact 2 until the contacts are closed. Exhaust valves 6 and 7 remain closed during this operation.

With this arrangement, exhaust valve 7 is actuated by the compressed air which passes through the hollow con- -tacts 2 4and 3 when in the closed position. A special air supply pipe for actuating the exhaust valve 7 can be dispensed with.

The advantage of this arrangement is the saving in control piping for circuit breakers with double nozzles which are kept under pressure when in the open condition.

What I claim is:

1. In an air-blast circuit breaker the combination comprising a casing establishing therein a switch chamber which is continuously subjected to a lling with compressed air, a pair of tubular contact members arranged co-axially within said switch chamber, said tubular contact members including nozzle type inlets at one end thereof adapted to engage each other, one of said contact members being stationary and the other movable and including a spring loaded piston member always having one side thereof exposed to the pressure of the air within said switch chamber, a first housing located within said switch chamber and which includes a cylinder for said piston in one part thereof and a valve chamber in .another part thereof in communication with the other end of said movable contact member and also with the other side of said piston member, a first spring loaded exhaust valve in said valve chamber, said exhaust valve being closed to close oitsaid valve chamber when the nozzle ends of said contact members are engaged and actuata'bie to an open position to vent said valve chamber and the interior of said movable contact member to atmosphere when it is desired to effect disengagement of said contact members, a second housing communicating with the opposite end of said stationary contact member, a normally closed second exhaust valve located in one part of said second housing and which controls the venting of said stationary contact member to atmosphere, and a second piston connected to said second exhaust valve, said second piston being slidable in a cylinder part of said second housing and always exposed on one side to the air pressure within said'second housing, the other side of said second piston together with said cylinder establishing a pressure chamber effective to shift said second piston and said second exhaust Valve to the open position upon a drop in air pressure in the part of said second housing which contains said second exhaust valve.

2. An air blast circuit breaker as delined in claim 1 wherein said second piston is provided with openings therethrough controlled by non-return valve means for passing compressed air into said pressure chamber when said second exhaust valve is closed.

3. An air blast circuit breaker as defined in claim 1 wherein said second piston is provided with openings therethrough controlled by non-return valve means for passing compressed air into said pressure chamber when said -second exhaust valve is closed, and which also includes spring means biasing said second exhaust valve to a closed position, said second piston also including a bleed opening therethrough for equalizing the pressure in said pressure chamber and that part of Vsaid second housing which contains said second exhaust valve after said non-return valves have closed.

References Cited by theExaminer UNITED STATES PATENTS 2,574,334 l1/51 Latour ZOO- 148 3,093,717 6/63 Forwald ZOO-148 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims

1. IN AN AIR-BLAST CIRCUIT BREAKER THE COMBINATION COMPRISING A CASING ESTABLISHING THEREIN A SWITCH CHAMBER WHICH IS CONTINUOUSLY SUBJECTED TO A FILLNG WITH COMPRESSED AIR, A PAIR OF TUBULAR CONTACT MEMBERS ARRANGED CO-AXIALLY WITHIN SAID SWITCH CHAMBER, SAID TUBULAR CONTACT MEMBERS INCLUDING NOZZLE TYPE INLES AT ONE END THEREOF ADAPTED TO ENGAGE EACH OTHER, ONE OF SAID CONTACT MEMBERS BEING STATIONARY AND THE OTHER MOVABLE AND INCLUDING A SPRING LOADED PISTON MEMBER ALWAYS HAVING ONE SIDE THEREOF EXPOSED TO THE PRESSURE OF THE AIR WITHIN SAID SWITCH CHAMBER, A FIRST HOUSING LOCATED WITHIN SAID SWITCH CHAMBER AND WHICH INCLUDES A CYLINDER FOR SAID PISTON IN ONE PART THEREOF AND A VALVE CHAMBER IN ANOTHER PART THEREOF IN COMMUNICATION WITH THE OTHER END OF SAID MOVABLE CONTACT MEMBER AND ALSO WITH THE OTHER SIDE OF SAID PISTON MEMBER, A FIRST SPRING LOADED EXHAUST VALVE IN SAID VALVE CHAMBER, SAID EXHAUST VALVE BEING CLOSED TO CLOSE OFF SAID VALVE CHAMBER WHEN THE NOZZLE ENDS OF SAID CONTACT MEMBERS ARE ENGAGED AND ACTUATABLE TO AN OPEN POSITION TO VENT SAID VALVE CHAMBER AND THE INTERIOR OF SAID MOVABLE CONTACT MEMBER TO ATMOSPHERE WHEN IT IS DESIRED TO EFFECCT DISENGAGEMENT OF SAID CONTACT MEMBERS, A SECOND HOUSING COMMUNICATING WITH THE OPPOSITE END OF SAID STATIONRAY CONTACT MEMBER, A NORMALLY CLOSED SECOND EXHAUST VALVE LOCATED IN ONE PORT OF SAID SECOND HOUSING AND WHICH CONTROLS THE VENTING OF SAID STATIONARY CONTACT MEMBER TO ATMOSPHERE, AND A SECOND PISTON CONNECTED TO SAID SECOND EXHAUST VALVE, SAID SECOND PISTON BEING SLIDABLE IN A CYLINDER PART OF SAID SECOND HOUSING AND ALWAYS EXPOSED ON ONE SIDE TO THE AIR PRESSURE WITHIN SAID SECOND HOUSING, THE OTHER SIDE OF SAID SECOND PISTON TOGETHER WITH SAID CYLINDER ESTABLISHING A PRESSURE CHAMBER EFFECTIVE TO SHIFT SAID SECOND PISTON AND SAID SECOND EXHAUST VALVE TO THE OPEN POSITION UPON A DROP IN AIR PRESSURE IN THE PART OF SAID SECOND HOUSING WHICH CONTAINS SAID SECOND EXHAUST VALVE.