Arc-extinguishing fragmentation chimney plate, chimney and circuit breaker comprising same

Abstract

The plate (36) of chimney (32) of fragmentation and arc extinguishing of a DC circuit breaker (10), the plate (36) delimits in its center a central light (40) with closed contour, the plate has on at least one face projections (42) delimiting between them radial channels (44) connecting, along the surface of the plate, the light (40) to the periphery of the plate, characterized in that it has means for modifying the open state of at least one channel (44) between two adjacent projections (42).

Description

[0001] The present invention relates to a fragmentation and arc-extinguishing chimney plate for an air-break DC circuit breaker, of the type having a central, closed-contour opening, the plate having projections on at least one face that define radial channels connecting the opening to the periphery of the plate along its surface, characterized in that it includes means for modifying the open state of at least one channel between two adjacent projections. It further relates to a chimney and a DC circuit breaker.

[0002] In installations powered by high-voltage direct current, and particularly in railway vehicles, disconnecting loads from the network requires opening circuit breakers while a significant voltage exists between the contacts. This high potential difference creates an electric arc that must be extinguished.

[0003] For this purpose, it is known to provide, in the extension of the circuit breaker bodies, a chimney delimiting a straight conduit inside which the arc develops in a U shape from one contact to the other.

[0004] The chimney is made up of plates arranged one on top of the other. These plates delimit radial ducts between them, allowing the exhaust gases and heat to escape along the entire length of the chimney flue.

[0005] Each of these plates extends inside the chimney flue with metal blades that fragment and gradually extinguish the flame. Plates and a chimney as described in the preamble are known from WO 2020 / 241397 A1.

[0006] Because the arc is very energetic, the chimney is relatively large and the circuit breaker is therefore a bulky object, especially in a railway vehicle.

[0007] The invention aims to limit the size of the chimney while allowing satisfactory extinction of the arc.

[0008] To this end, the invention relates to a flue plate for arc splitting and extinguishing of a DC circuit breaker of the aforementioned type, characterized in that it comprises means for modifying the open state of at least one channel between two adjacent projections.

[0009] Depending on specific embodiments, the plate includes one or more of the following characteristics: It includes at least one frangible wall connecting two adjacent projections and closing a radial channel; the frangible wall is formed from the rest of the plate; between the central lumen and the periphery of the plate, at least one slit passes through the thickness of the plate and extends along the entire width of the channel between two adjacent projections across the radial channel; and the central lumen has an oblong shape and exhibits a lateral widening in its middle part.

[0010] The invention also relates to a chimney for splitting and extinguishing an arc of a DC circuit breaker comprising a stack of plates as described above with alignment along the same axis of the central lights of the plates to delimit a chimney duct, the channels of a plate delimiting, with the adjacent plate resting on the projections, radial evacuation ducts opening outwards through outlet vents.

[0011] Depending on the specific design, the chimney may have one or more of the following characteristics: a part of the plates have a frangible wall in place and a part of the plates have a free passage at the place of the frangible wall which has been broken, it includes a sealing flap received in at least two aligned slots of adjacent plates, sealing at least one duct delimited between two plates; it includes, for each plate, at least one metal blade interposed between two plates and protruding partially into the chimney duct; and it includes at least one screen attached to the periphery of the plates and separating the outlet vents.

[0012] Finally, the invention relates to a direct current circuit breaker comprising a chimney as defined above and a switch disposed in the extension of the chimney flue.

[0013] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the drawings in which: [Fig 1 ] There figure 1 is a side and cross-sectional view of a DC circuit breaker; [ Fig 2 ] There figure 2 is a perspective view of a plate in its initial configuration used in the construction of the switch's chimney figure 1 ; Fig 3 ] There figure 3 is a view identical to that of the figure 2 of a plate on which frangible walls have been broken; [ Fig 4 ] There figure 4 is a perspective view of the switch of the figure 1 in which only certain constituent plates of the chimney have been depicted; and [ Fig 5 ] There figure 5 is a view identical to the figure 4 showing a shutter flap in place.

[0014] The circuit breaker 10 shown on the figure 1 is intended to be installed on board a railway vehicle.

[0015] It has two connection terminals, 12 and 14. One is designed to be connected to a DC power source, such as a pantograph connected to the power grid. The other terminal is intended to be connected to loads such as the vehicle's drive motors.

[0016] The circuit breaker 10 has a body 16 in which is arranged a switch 18, one of whose contacts, which is movable, 20 is connected to terminal 16 and whose other fixed contact 22 is connected to terminal 12.

[0017] The movable contact 20 is secured to terminal 14 by a conductive braid 24. An actuator 26 is disposed in the body 16 to ensure movement of the movable contact 20 between a position away from the fixed contact 22 as illustrated in the figure 1 and a position in contact with the fixed contact 22 allowing the flow of electric current between terminals 12 and 14.

[0018] The body 16 is surmounted at the contacts 20, 22 by a chimney 30 for fragmentation and extinction of the electric arc formed between the two terminals 20, 22 when the switch 18 is opened.

[0019] The chimney 30 has a parallelepiped external shape. It has in its center an axial chimney flue 32 whose axis is aligned with the contacts 20, 22. The chimney flue is closed opposite the contacts 20, 22 by a cover 34.

[0020] The chimney is formed from a stack of 36 individual plates, an example of which is shown in figures 2 And 3 following two distinct configurations.

[0021] Between these plates are radial conduits 38 connecting the chimney flue 32 to the outside. These conduits open via vents 39 for releasing gases and heat produced by the arc into the external environment.

[0022] All the plates forming chimney 30 are initially, before assembly and configuration, identical to that marked 36A of the figure 2 These plates are rectangular in shape and have in their center an oblong opening 40, delimiting the chimney flue. This oblong opening is centered in the plate and its long axis coincides with the long axis of the rectangular plate.

[0023] On only one of its faces, the plate has 42 projections, 10 of which are on the figure 2 The projections form flat bearing surfaces on their upper part for the support of the immediately superimposed plate. Some projections have a hole that passes completely through the plate. These holes allow for the insertion of screws to fasten the plates together; these screws extend along the entire height of the chimney.

[0024] The projections are each adjacent to the periphery of the plate and they delimit, with the flat part of the plate, channels 44 connecting the opening 40 and the periphery of the plate where the vents 39 are formed. These channels 44, when covered by a plate resting on the projections 42, delimit the ducts 38 visible on the figure 1 .

[0025] The projections are distributed in groups of five along the longer sides of the plates. The median projections have dovetail-shaped slides 46 on the edge of the plate, according to its thickness, designed to receive screens, as will be described later.

[0026] The central light 40 has, in its middle part, on each side, a local enlargement 47 at the level of the median channels noted 48. These enlargements 47 locally increase the cross-section of the chimney flue.

[0027] The median channels 48 are, at the end of the plate manufacturing process, each closed by a frangible wall 50 extending between the two adjacent projections 42. The wall 50 extends across the entire thickness of the plate, thus ensuring complete obstruction of the channel. The wall is formed on the edge of the opening 40 delimiting the chimney flue.

[0028] These 50 walls came from the material with the plates, which are generally made of plastic material.

[0029] These walls are frangible, meaning they can be broken manually or with a suitable tool to allow an opening of channel 48, initially closed by wall 50. A free passage, designated by 60 on the figure 3 , is then formed at the location of wall 50 which was broken on the plate designated by reference 36B.

[0030] Behind the walls 50, in a median position along the length of the median channels 48, the plate has transverse slots 52 extending over the entire width of the conduit from one projection 42 to the opposite projection.

[0031] As illustrated on the figure 4 where some plates have been removed, the plates are stacked on top of each other with lights aligned 40 in line with switch 18.

[0032] In addition, metal blades 62 are supported by each plate on supports 64 at mid-height of the projections 42 visible on a larger scale on the figure 2 These metal blades protrude partially into the chimney flue 32.

[0033] In the stacking of the 36 plates forming the chimney and as visible on the figure 1 The lower plates near switch 18 are advantageously identical to those 36A of the figure 2 and present a 50 wall blocking the median canals as visible on the figure 4 , thus blocking the corresponding radial conduits 38.

[0034] On the contrary, in the upper part and as visible on the figure 1 , that is to say, opposite body 16, the plates marked 36B are identical to those appearing on the figure 3 and present a free passage 60 at the location of the walls 50, the latter having been broken to allow the circulation of gases through the conduit arranged at the rear between the two projections 42.

[0035] It is understood that, during the operation of the chimney, the arc is contained within the lower part of the chimney, and the gases cannot circulate through the medial lateral flues, which are blocked in the lower section. Conversely, in the upper part of the chimney, the gases are free to circulate through the medial lateral flues.

[0036] Advantageously, in the middle part of the chimney in the area designated by 70 on the figure 1 , in which the plates are 36B plates whose walls have been broken, a shutter 80 as more clearly illustrated on the figure 5 is arranged in the slots 52, thus allowing the corresponding conduits 38 to be closed in their middle part while allowing the open section of the chimney duct to be increased for the guidance of the arc.

[0037] As illustrated on the figure 4 , the notches 46 receive screens 47, these screens 87 being formed of a plate in particular rectangular carrying on one of the sides a complementary profile 88 to the profile of the groove 46, thus allowing their introduction by sliding and their retention.

[0038] These screens allow separation of the hot gas flows exiting laterally from the chimney during the propagation and extinction of the arc.

[0039] It is understood that the use of initially identical plates equipped with means of controlling the state of opening of the radial ducts makes it possible to adapt the structure of the chimney according to the type of arc to be extinguished and thus to optimize the extinguishing while maintaining a relatively small footprint of the chimney.

Claims

1. Direct-current circuit breaker (10) arc-extinguishing fragmentation chimney (32) plate (36), the plate (36) delimiting at the centre thereof a central hole (40) with a closed contour, the plate comprising on at least one face projections (42) delimiting between them radial channels (44) connecting, along the surface of the plate, the hole (40) to the periphery of the plate, characterised in that it comprises means for modifying the opening state of at least one channel (44) between two adjacent projections (42).

2. Plate according to claim 1, characterised in that it comprises at least one frangible wall (50) connecting two adjacent projections (42) and sealing a radial channel (44).

3. Plate according to claim 1 or 2, characterised in that the frangible wall (50) is integral with the rest of the plate.

4. Plate according to any one of the preceding claims, characterised in that it comprises, between the central hole (40) and the periphery of the plate, at least one slot (52) passing through the thickness of the plate and extending along the entire width of the channel (44) between two adjacent projections (42) through the radial channel (44).

5. Plate according to any one of the preceding claims, characterised in that the central hole (40) has an oblong shape and has a lateral widening (47) in the medial part thereof.

6. Direct-current circuit breaker (10) arc-extinguishing fragmentation chimney comprising a stack of plates (36) according to any one of the preceding claims with alignment along the same axis of the central holes (42) of the plates to delimit a chimney flue (32), the channels (44) of a plate delimiting, with the adjacent plate bearing on the projections (42), radial exhaust ducts (38) opening outwards by outlet vents (39).

7. Chimney according to claim 6, the plates having the features of any one of claims 2 and 3, characterised in that part of the plates (36A) have a frangible wall (50) in place and part of the plates (36B) have a free passage at the location of the frangible wall (50) which has been broken.

8. Chimney according to claim 6 or 7, the plates having the features of claim 4, characterised in that it comprises a sealing flap (80) received in at least two aligned slots (52) of adjacent plates, sealing at least one duct (38) delimited between two plates (36).

9. Chimney according to any one of claims 6 to 8, characterised in that it comprises, for each plate (36), at least one metal strip (62) interposed between two plates (36) and projecting partially into the chimney flue (32).

10. Chimney according to any one of claims 6 to 9, characterised in that it comprises at least one screen (47) mounted on the periphery of the plates (36) and separating the outlet vents (40).

11. Direct-current circuit breaker comprising a chimney according to any one of claims 6 to 10 and a switch (18) disposed in the extension of the chimney flue (32).

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