ES2300964T3 - ELECTRIC CUTTING DEVICE WITH ARC EXTINGUISHING CAMERA WITH DEIONIZATION FINS. - Google Patents

Abstract

The switchgear has an electric arc extinguishing chamber, opening on an opening volume (35), with a stack of de-ionization blades separated by an exchange gap. Free leading edges of the blades are exposed to an electric arc and delimit a recess (9) of asymmetrical form and formed to create, when the blades are alternatively stacked, chimneys (15) whose passages are closed in a plane perpendicular to chimneys` longitudinal axis.

Description

Electric cutting device with camera arc extinction with deionization fins.

Technical scope of the invention

The invention relates to a device electric cutting that involves a box that has a plane Longitudinal geometric reference, a pair of contacts separable electrical arranged in an opening volume, a arc extinguishing chamber that opens at the opening volume and which is delimited by two parallel side walls and placed to one and another part of the geometric reference plane, a wall rear away from the opening volume, a bottom wall and a upper wall The arc extinguishing chamber comprises a stacking of at least two separate deionization fins about of others for an exchange space, each fin having a leading edge intended to be exposed to the arc. At least one Exchange space is attached to at least one conduit of evacuation by means of at least one evacuation hole.

State of the art

The presence of electrical failures inside of cutting devices such as circuit breakers, switches or electrical contactors causes a sudden opening of your contacts electric This quick separation of contacts is accompanied usually from the production of an electric arc. The energy of arc and gas discharges that accompany the production of said arc give rise to important limitations in the mechanisms and run the risk of damaging the device.

To reduce the time of presence of the short circuit current and thereby reduce the effort Thermal supported by the electric cutting device, voltage arc rises as quickly as possible until it is done higher than the applied voltage. This causes the cancellation of the short circuit current. When the resistance is found dielectric of the air between the separated contacts thus prevents a re-ignition or other arc bursts.

The electric arc should cool as much quickly possible always staying away from contacts electric This cooling is usually done by placing the arch inside an arc extinguishing chamber that involves a stack of metal plates called fins of deionization In practice, the electric arc, which has just occur, is driven in the chamber by electrodynamic forces induced by a magnetic field due to the current flowing In the drivers.

During its displacement, the arch tends to move between the side walls of the extinguishing chamber arc generally occupying the recesses present in the fins. These recesses favor the migration of the arch towards the bottom of the camera. In addition, the stacking of the fins causes a clipping of the arch and facilitates its insertion in the arc extinguishing chamber 10. The fins offer the arc a heat exchange surface throughout the cut. At the time of the progression of the arch in the camera, the latter tends to expand to invade the entire space available. The fins contain this dilation interacting with  the periphery of the arch. The arc tension increases as far as That the bow cools. In addition, the pressure in the cutting volume intensely

If the shape of the recesses is not optimized, it can attend repetitive arc reinterruptions between contacts

Some documents (FR-2,839,195) disclose rebates that end with a chimney that tends to stabilize the arch in a remote region of the opening volume of the contacts. However, the shape of the recess characterized by the presence of a passage that passes from the production area of the arch to the chimney can drag a sending hot gases and vapors in the direction of the area of opening of the contacts and thus causing a leakage of the arc from the Camera towards contacts. This leak is accompanied by repetitive reinterruptions.

In addition, arc production entails concomitant the production of a significant amount of vapors metallic or gases, which may, be evacuated or not, be responsible mainly of a link arc between the phases of the device Electric cut and create an explosion.

Numerous existing solutions provide for at least an evacuation channel of said gases outside the area next to contacts. These gases are generally expelled at exterior of the electric cutting device.

These solutions, although they have advantages, they can also generate noise in the premises where they are placed the cutting devices. Indeed, being these gases still hot and intensely ionized, can cause effects ominous.

In order to avoid this contamination of outside environment, other solutions propose a recycling of gases internally (documents GB-2,285,889, US-5,731,561, FR-1,400,079). He document "US-A-4,612,426" describes an electric cutting device according to the preamble of the claim 1.

These solutions may present certain inconvenience This recycling of gases internally is usually accompanied by an increase in the volume of the device electric cutting In effect, the gases are conducted generally in specific volumes that are beyond The arc extinguishing chamber. In addition, the channels used for the gas conduction, can, due to its geometry, induce pressure plugs responsible for a bad evacuation or a slowdown of these gases.

Exhibition of the invention

The invention thus seeks to remedy the inconveniences of the state of the art, so that it proposes a electric cutting device that carries the fins of deionization allowing rapid arc cooling electric.

The attack-free edge of at least two of the fins of the device according to the invention delimits a recess that it flows asymmetrically in and forms two lateral branches, said recess being made so that it is created, when said fins are stacked alternately, at least one chimney whose duct appears as substantially closed in a plane perpendicular to the axis longitudinal of said chimney.

Advantageously, the device comprises according to the z axis, at least two areas of alignment between a lateral branch of a first fin and at least one lateral branch of a second fin that has experienced, with respect to said first fin, a 180º rotation around its longitudinal axis.

In a preferred embodiment of the invention, the free edge of attack of the fins is in contact at least twice with the longitudinal axis of said fins.

In a preferred embodiment of the invention, the free leading edge of the fins cuts at least Twice the longitudinal axis said fins.

Advantageously, the cutting device it comprises, according to the z axis, at least one coating zone between a lateral branch of a first fin and at least one lateral branch of a second fin that you have experienced, regarding that first fin, a 180º rotation around its axis longitudinal.

Preferably, the attack-free edge of the recess delimits an enlarged first anterior part that leads to in the opening volume and a second longitudinal back which extends towards the back wall, the first anterior part widened is cut by the longitudinal axis of the fins.

According to a form of development of the invention, each fin is placed next to another fin that has experienced a 180º rotation with respect to its longitudinal axis.

According to a particular form of development of the invention, at least one evacuation duct extends in at minus an evacuation hole towards an opening, along the less a side wall, said duct, according to the z axis of the entrance of the gases to its exit of said conduit, a substantially constant or increasing section, said opening being (18) at least equal to the largest section of said conduit and being placed in front of the electrical contacts of the volume of opening.

Preferably, each exchange space of the extinguishing chamber has at least one evacuation hole attached to at least one evacuation duct.

Preferably, the device involves the at least two evacuation ducts, extending at least one duct along each side wall of the extinguishing chamber of Arc.

Advantageously, the exchange spaces of the extinguishing chamber has at least two holes of evacuation, with at least one hole attached to each of the evacuation ducts that extend along each wall.

Preferably, the evacuation holes they are placed in an area between the back wall and the middle axis of the fins.

The evacuation holes are placed in the side walls.

The evacuation holes are placed in the back wall.

The evacuation ducts have a shape noticeably parallelepipedic.

Brief description of the figures

Other advantages and features will result more evident from the description proposed below of a particular embodiment of the invention, given by way of non-limiting example, and represented by the attached drawings in which:

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fig. 1 represents a side view of a electric cutting device according to a first form of preferred embodiment of the invention;

fig. 2 represents a sectional view according to a plane II of an electric cutting device according to fig. one;

fig. 3 represents a sectional view according to a plane JJ of an electric cutting device according to fig. 2;

fig. 4A represents a detailed view of a deionization fin of an electric cutting device according to fig. one;

fig. 4B represents a detailed view of a stacking of deionization fins according to fig. 4A;

fig. 5A, 5B respectively represent a detailed view of a fin and a stack of fins deionization of an electric cutting device according to a variant of the first preferred embodiment of the invention;

fig. 6A represents a detailed view of a deionization fin of an electric cutting device according to a second preferred embodiment;

fig. 6B represents a detailed view of a stacking of deionization fins according to fig. 6A;

fig. 7A, 7B respectively represent a detailed view of a fin and a stack of fins deionization of an electric cutting device according to a variant of the second preferred embodiment of the invention;

fig. 8A to 10B represent variants of realization of deionization fins of the extinguishing chamber of arc;

fig. 11 represents a variant of embodiment of an electric cutting device according to fig. one.

Detailed description of an embodiment

According to a first embodiment preferred presented in fig. 1, 2 and 3, the electrical device  cutting 30 comprises a box 31 of molded plastic material in which has at least one fixed contact 32 associated with at least a mobile contact 33. One or more detection devices failures, especially short circuits, act on a mechanism of drive 34 that drives the opening of the mobile contact 33.

Box 31, due to its shape, defines a plane longitudinal geometric reference xz.

In this embodiment presented, the electric cutting device comprises two fixed contacts 32 in U connected respectively to an electrical connection terminal. He mobile contact 33, which can travel in translation under the action of drive device 34, allows joining electrically the two fixed contacts 32. The mobile contact 33 It has two contact zones 36 that can collaborate each respectively with a fixed contact 32. Thus two are defined opening volumes 35 corresponding to the space in which a fixed contact 32 and a contact area 36 are arranged associated with the mobile contact 33.

In addition, each opening volume 35 is associated with an arc extinguishing chamber 10. The arc extinguishing chamber 10 that opens in the opening volume 35 is delimited by two side walls 11 parallel and placed on either side of the longitudinal geometric plane of reference xz, a rear wall 6 away from the opening volume 35, a bottom wall 7 and a upper wall 8.

The arc extinguishing chamber 10 comprises a stacking of at least two flat 1 deionization fins and perpendicular to the longitudinal geometric plane of reference xz. These fins are substantially rectangular in shape and involve a longitudinal axis 12 as well as a middle axis 13. These fins they comprise two main parts: a first first part 13a which is in front of the opening volume 35 and which extends from the front face of the extinguishing chamber 10 to the middle axis 13, and a second rear part 13b extending from the middle axis 13 to the back wall 6.

Each fin 1 has an attack free edge 5 intended to be exposed to the arch. The attack free edge 5 forms a recess 9 that flows and extends along the axis longitudinal 12, of the front face of the extinguishing chamber 10 towards the back wall 6. This recess 9 delimits two branches lateral 1a, 1b.

The recess 9 of at least two fins 1 is of shape Asymmetric and has two parts. Behaves a first part enlarged anterior 9a in front of contacts 32, 33 placed in the opening volume 35 and a second part longitudinal posterior narrower 9b.

According to a preferred embodiment of the invention, as depicted in fig. 6A, 7A, the edge of attack 5 that runs along the flat surface of said at least two fins is at least twice in contact at points a, b with the longitudinal axis 12 of the fins. In another embodiment Preferred invention, as shown in fig. 4A and 5A, the leading edge 5 cuts three times at points a, b, c the axis longitudinal 12 of said at least two fins.

According to these preferred embodiments of the invention, the recess 9 is made so that when two fins are stacked alternately, there are, according to the z axis, at least two alignment zones a and b between a side branch 1a of a first fin 1 and at least one lateral branch 1a of a second fin 1 placed in an alternate position. A flap is in an alternate position with respect to another when it has experienced a 180 ° rotation around its longitudinal axis 12. Preferably, the first alignment zone a is located in the anterior part 13a of the
fin 1.

When the leading edge 5 cuts three times the longitudinal axis 12, there are three areas of alignment a, b and c between a lateral branch 1a of a first fin 1 and at least one branch side 1a of a second fin 1 placed in a position alternated There is then a covering area 50 of the branches 1st sides. Each fin has a coating area 50 bounded by the intersection, at points a and b, between the axis longitudinal 12 and leading edge 5 of the first lateral branch 1st.

According to these two preferred forms of embodiment of the invention, the two lateral branches 1a, 1b are placed sensitively to both sides of said axis longitudinal 12 and the first enlarged anterior part 9a is cut by the longitudinal axis 12.

In the embodiment examples as depicted in fig. 1 to 11, all fins placed on the arc extinguishing chamber 10 have the same recess 9. The stacking the set of fins 1 of the extinguishing chamber arc 10 is performed so that at least two of the fins are stacked alternately so that the shapes of its recess 9 They don't match.

Advantageously, all fins 1 are stacked alternately, so that each fin 1 is placed next to another fin that has experienced a 180º rotation with respect to its longitudinal axis 12.

Given the fact of the asymmetric shape of the recesses 9 of fins 1 and alternating stacking of said fins, a chimney 15 is formed whose duct appears as substantially closed in an x plane and perpendicular to the axis longitudinal 16 of said chimney 15.

In the exemplary embodiment, the chimney 15 is extends across the entire height of the chamber, from the bottom wall 8 to the upper wall 7.

Depending on the shape of the recesses 9 of the fins 1, the shaft 16 of the chimney 15 will be more or less close to the rear wall 6 of the arc extinguishing chamber 10. The chimney 15 is preferably placed at the height of the middle axis 13 of fin 1 or beyond said axis towards the rear wall 6.

The fins are made in conductive material with steel base. The deionization fins 1 stacked ones on others are separated from each other by an exchange space 2. The thickness of each exchange space 2, slightly greater than fin thickness.

The gases or metal vapors present in the arc extinguishing chamber 10 can be evacuated so traditional by means of at least one evacuation channel attached to one or several exchange spaces 2 through holes of evacuation. Gases can be expelled outside the electric cutting device with the risk of causing noise in the premises in which the devices are placed cut.

In a particular embodiment of the invention, then gas recycling means are used. At least an exchange space 2 is connected to at least one conduit of evacuation 3 by means of at least one evacuation hole 4. Said at least one evacuation duct 3 is intended for a part to the evacuation of the gases from the extinguishing chamber 10 and on the other hand to the injection of said gases, by means of a opening 18, at contacts 32, 33 of the opening volume 35. In addition, said at least one evacuation conduit 3 extends from at least one evacuation hole 4 towards the opening 18, at length of at least one side wall 11. Said opening 18 is placed against electrical contacts 32, 33 of the opening volume 35

The gases then occupy a flow conduit composed of at least one evacuation hole 4, at least one evacuation duct 3 and at least one opening 18. Said evacuation ducts 3 carry, in all their length and following the x-axis, a constant or increasing section A. Further, said evacuation ducts 3 also preferably behave a constant section along the y and z axes. In other words, of the entrance to the exit of the gases from the evacuation ducts 3, the section of said ducts is substantially constant. Advantageously the section of said ducts may be increasing. The opening 18 is at least equal to the largest section A of said conduit.

In general, the section of a duct flow occupied by gases must be kept at least constant or increase. This geometric peculiarity favors the flow of gases that come from exchange spaces 2 and thus limit the creation of pressure plugs that can be formed along the flow conduit A decrease in the duct section of flow, in particular at the height of the evacuation duct 3 or of the opening 18 could cause the production of pressure plugs. These pressure plugs could generate a brake in the gas progression as well as arc progression electric.

Advantageously, in the embodiment preference of the invention presented in fig. 1 to 3, each swap space 2 is attached to at least one conduit of evacuation 3 by means of at least one evacuation hole 4. The shape and dimension of the evacuation holes 4 are such that The gas flow does not involve the passage of the arc through these holes. In order to avoid short circuits between fins 1, by means of the electric arc, the evacuation holes are made of independent way and do not communicate with each other.

Preferably, at least two are present evacuation ducts 3 so that at least one conduit 3 along each side wall 11 of the chamber of arc extinction 10. In the embodiment presented in fig. 1 and 2, each evacuation duct placed next to a side wall 11, extends from the evacuation holes 4 towards an opening 18, from the lower wall 8 to the upper wall 7 and along the side wall 11.

In a preferred embodiment according to the invention as depicted in fig. 1 to 3, two are used evacuation ducts 3. An evacuation duct 3 is placed at the side of each of the side walls 11 of the chamber of arc extinction 10. Each exchange space 2 involves the minus an evacuation hole 4 attached to an evacuation conduit 3. The evacuation holes 4, placed on the side walls 11, are arranged in an area between the rear wall 6 and the middle axis 13 of the fins 1. In addition, the ducts are of noticeably parallelepipedic form.

The equipment works as follows. During the appearance of a short circuit, the electromagnetic field induced by the current flowing in the conductors and over all in the fixed contact 32, begets in the mobile contact 33 electrodynamic forces that reject mobile contact in position of separation, confirming this movement then by the opening of the drive mechanism by means of mechanism 34. From the separation of the contacts 32, 33, a electric arc between said contacts. This bow is pushed to the arc extinguishing chamber 10 by electrodynamic forces. During its movement to chimney 15 and the back wall 6, the arch remains halfway between the side walls 11, since it tends to occupy the openings 9 open between the fins

The fins 1 offer the arch a surface of thermal exchange during the entire cut, especially in its part in proximity to the edges 5. In the course of its progression in the arc extinguishing chamber 10 or when installed in the fireplace 15, the arch tends to expand to invade the entire space available. The fins 1 contain this dilation interacting with the periphery of the arch. When the arch is placed in the chimney 15, the heat exchange is distributed evenly around of the arc and thus optimize its cooling and accelerate its extinction. The arc tension increases as the arc cools, which finally allows the extinction of the arc during passage of electric current through zero.

The recesses 9 favor the migration of the arch towards the bottom of the arc extinguishing chamber 10, and the chimney 15 stabilizes the arch in this region. This fireplace 15, away from the opening volume, allows the arc to stabilize and not Repeatedly interrupt between contacts. So, it is the conjunction of the shape of the recess and the respective position of the fins with respect to each other which allows to move away from Fast and durable contact arc.

In addition, through the evacuation ducts 3, a gas convection is established so that the progression from the arch to the rear wall 6 is not hindered by an increase of pressure. The arch foot quickly migrates from the fixed contact 32 to chimney 15, before mobile contact 33 has reached its final separation position.

In practice, the gases emitted in the periphery of the arch and present in the exchange spaces 2 are injected into the opening volume 35 through the ducts of flow composed of evacuation holes 4, conduits of evacuation 3 and openings 18. The homogeneous and regular distribution of gases evacuated through the flow ducts reduce the risk of pressure plugs responsible for slowing the progression  of gases and arc progression. Indeed, an increase local pressure or the presence of cold gas, before the arc, can lead to a slowdown in its movement.

The circulation of gases in the conduits of flow in the direction of the electrical contacts 32, 33 of the opening volume 35 allows decompression of said gases included, as well as faster cooling of these last.

The injection of the cooled gases in the contacts 32, 33 present in the opening volume 35 allows increase dielectric strength in this space and avoid untimely reinterruptions of the electric arc. Is also contact injection allows the plasma present in the opening volume 35 and the arc extinguishing chamber 10 at a anterograde flow of cold and weakly ionized gases. This causes a cooling of the antegrade area of the arch but also sending hot gases before the arc. Because of his antegrade cooling, the arc that tends to develop in presence of ionized hot gases associated with vapors metallic, moves towards the rear face 6 of the chamber of extinction 10 and thus moves away from the opening area of the contacts

According to a first series of variants of embodiment as depicted in fig. 8A and 9A the edge of attack 5 that runs along the flat surface of fins 1 and that forms the recess 9 asymmetrically cuts five times at points a, b, c, d, e the longitudinal axis 12 of said fins. Due to the asymmetric shape of the recesses 9 of each fin 1 and the stacking in alternation of said fins, two chimneys 15 are formed whose conduits 16 appear respectively as substantially closed in a plane perpendicular xy to the longitudinal axis 16 of said chimneys 15.

According to a second series of variants of embodiment as depicted in fig. 10a and 10b, the edge of attack 5 that runs along the flat surface of the fin and that forms the recess 9 asymmetrically cuts the longitudinal axis twice 12 of said fin. In addition, the first widened longitudinal part 9a is placed beyond the longitudinal axis 12 of the fins 1.

In another embodiment variant such as depicted in fig. 11, exchange spaces 2 involve at least one evacuation hole 4 placed in the rear wall 6 and attached to an evacuation duct 3. According to this example of embodiment, each exchange space 2 has two holes of evacuation 4; each of the holes is connected respectively to an evacuation duct 3.

In another variant embodiment, each hole 4 is connected autonomously to an opening 18 by means of its own evacuation duct 3. Indeed, each duct of evacuation 3 remains independent of the other ducts of evacuation.

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References cited in the description

This list of references cited by the applicant only intends to help the reader and is not part of the European patent document. Even when the maximum has been set careful in its elaboration, errors or omissions cannot be excluded and the EPO declines all responsibility in this regard.

Patent documents cited in the description

? FR-2,839,195 [0007]

FR-1,400,079 [0011]

? GB-2,285,889-A [0011]

? US-4,612,426-A [0011]

? US-5,731,561-A

Claims (15)

1. Electric cutting device that behaves:

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a box (31) having a longitudinal reference geometric plane (xz),

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a pair of separable electrical contacts (32, 33) arranged in one volume opening (35),

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a arc extinguishing chamber (10) that opens in the volume of opening (35) and which is delimited by two side walls (11) parallel and placed to one and another part of the geometric plane of reference (xz), a rear wall (6) away from the volume of opening (35), a lower wall (7) and an upper wall (8),

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to the minus two deionization fins (1) that have a leading edge (5) intended to be exposed to the arch and delimiting a recess (9) which flows asymmetrically in and forms two lateral branches (1a, 1b), said at least two fins being stacked in alternation, the fins being placed inside the arc extinguishing chamber (10)

characterized in that said recess (9) of said at least two fins (1) is made such that at least one chimney is created whose duct appears as substantially closed (15) in a plane perpendicular (xy) to the longitudinal axis (16) of said chimney (15). 2. Electrical cutting device according to claim 1 characterized in that it comprises, according to the axis (z), at least two alignment zones (a, b) between a lateral branch (1a) of a first fin (1) and at least one lateral branch (1a) of a second fin (1) that has experienced, with respect to said first fin (1), a 180 ° rotation around its longitudinal axis (12). 3. Electrical cutting device according to claims 1 or 2 characterized in that the free edge of attack (5) of the fins (1) is in contact at least twice with the longitudinal axis (12) of said fin. 4. Electrical cutting device according to claim 3 characterized in that the free edge of attack (5) of the fins (1) cuts at least twice the longitudinal axis (12) of said fin. 5. Electrical cutting device according to claim 4 characterized in that, according to the axis (z), there is at least one covering area (50) between a lateral branch (1a) of a first fin (1) and at least one lateral branch (1a) of a second fin (1) which has experienced, with respect to said first fin (1), a 180 ° rotation around its longitudinal axis (12). 6. Electric cutting device according to any one of the preceding claims characterized in that the leading edge (5) of the recess (9) delimits a first enlarged front part (9a) that flows into the opening volume (35) and a second longitudinal rear part (9b) extending towards the rear wall (6), the first widened front part (9a) is cut by the longitudinal axis of the fins (12). 7. Electric cutting device according to any one of the preceding claims characterized in that each fin (1) is placed next to another fin (1) that has undergone a 180 ° rotation with respect to its longitudinal axis (12). 8. Electric cutting device according to any one of the preceding claims characterized in that at least one evacuation duct (3) is connected to at least one exchange space (2) that separates two fins (1) by means of at least one hole of evacuation (4), said at least one evacuation conduit (3) extending from at least one evacuation orifice (4) towards an opening (18), along at least one side wall (11), said conduit behaving (3), along the axis (x) of the gas inlet at its exit from said duct, a section (A) substantially constant or increasing, said opening (18) being at least equal to the largest section (A) of said conduit (3) and being placed in front of the electrical contacts (32, 33) of the opening volume (35). 9. Electrical cutting device according to claim 8, characterized in that each exchange space (2) of the extinguishing chamber (10) comprises at least one evacuation hole (4) connected to at least one evacuation duct (3). 10. Electrical cutting device according to claims 8 or 9 characterized in that it comprises at least two evacuation ducts (3), at least one duct (3) extending along each side wall (11) of the arc extinguishing chamber (10) 11. Electric arc cutting device according to claim 10 characterized in that the exchange spaces (2) of the extinguishing chamber (10) have at least two evacuation holes (4), at least one hole being connected to each of the evacuation ducts (3) that extend along each wall (11). 12. Electric arc cutting device according to any one of the preceding claims characterized in that the evacuation holes (4) are placed in an area between the rear wall (6) and the middle axis (13) of the fins (1) . 13. Electric arc cutting device according to claim 12 characterized in that the evacuation holes (4) are placed in the side walls (11). 14. Electric arc cutting device according to claim 12 characterized in that the evacuation holes (4) are placed in the rear wall (6). 15. Electric cutting device according to any one of the preceding claims characterized in that the evacuation ducts (3) have a substantially parallelepipedic shape.