FR3121269A1 - electrical switchgear - Google Patents

Abstract

electrical switchgear Electric switching device (2), comprising a casing (4) and a breaking chamber (12) housed in the casing, the breaking chamber comprising a stack of metal plates (14), the switching device further comprising a separation piece (20) placed at the outlet of the interrupting chamber, the separation piece being placed in contact with the stack of metal plates, perpendicular to the metal plates, being at least partially inserted in the grid and/or between the metal plates of the stack, so as to separate the flow of gas leaving the interrupting chamber. Figure for abstract: 2

Description

electrical switchgear

The present invention relates to an electrical switching apparatus.

The invention is particularly applicable to the field of electrical protection and more particularly to miniature circuit breakers (MCB, for “Miniature Circuit Breaker” in English) used to protect low-voltage electrical installations.

Many electrical switching devices of the electromechanical type, such as circuit breakers, generally comprise an interrupting chamber configured to extinguish an electric arc which appears following a trip when the electrical contacts of the switching device open.

The interrupting chamber typically comprises a stack of metal plates superimposed one above the other to lengthen and thus extinguish the electric arc. The plates are held by support structures, such as side flanges. One or more holes in the casing allow the breaking gases to be discharged outside the switchgear.

In general, there is a need to improve the construction of such arc chutes, in particular with the aim of improving their performance, but also of making their manufacture and assembly simpler and less expensive.

To this end, one aspect of the invention relates to an electrical switching device, comprising a casing and an arcing chamber housed in the casing, the arcing chamber comprising a stack of metal plates, the switching apparatus further comprising a separation piece placed at the outlet of the interrupting chamber, the separation piece being placed in contact with the stack of metal plates, perpendicular to the metal plates, being at least partially inserted into the grid and/or between the metal plates of the stack, so as to separate the flow of gas leaving the interrupting chamber.

According to advantageous but not mandatory aspects, the electrical switching device may incorporate one or more of the following characteristics, taken individually or in any technically permissible combination:

- The partition piece has a main part in the form of a plate, the main part being aligned in the direction of the stack of metal plates.

- The separation piece has a curved L-shaped portion extending perpendicular to the main part.

- The separation piece comprises a plurality of positioning portions formed on one edge of the main part, the positioning pieces being configured to be inserted between the metal plates of the stack.

- The positioning portions have a lug shape.

- The positioning portions are formed in one piece with the separation piece.

- The separation piece is formed from an electrically insulating material, such as a thermoformed polymer.

- The switching device comprises a grid placed at the output of the stack of metal plates.

- The grid is at least partly formed by half-bars extending from the interior walls of the casing, the distal ends of the opposite half-bars delimiting a space in which the main part of the separation piece is inserted.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of an electrical switching device, given solely by way of example and made with reference to the accompanying drawings, in which:

there schematically shows, in a partial exploded view, an electrical switching device according to one embodiment of the invention;

there schematically represents, according to another partial and exploded view, the electrical switching device of the ;

there schematically shows, in a partial view, the electrical switching device of Figures 1 and 2;

there schematically represents views of internal walls of a casing of the electrical switchgear of the ;

there schematically represents, according to a partial view and in section, part of the interrupting chamber of the electrical switching device of the .

Figures 1, 2 and 3 show an example of an electrical switching device 2 according to embodiments of the invention.

Preferably, the switching device 2 is an electromechanical device.

For example, switchgear 2 is an electrical protective device, such as an air-break circuit breaker.

Preferably, the switching device 2 a miniature circuit breaker (MCB, for "Miniature Circuit Breaker" in English).

The switching device 2 is, for example, more particularly intended to be used to protect electrical installations at low electrical voltage (for example electrical voltages less than or equal to 1000 V AC).

The switching device 2 comprises a casing 4 which delimits an interior volume in which all or part of the components of the switching device 2 are housed.

For example, the casing 4 comprises a first casing part 6 and a second casing part 8 having complementary shapes and being intended to be combined to form the casing 4.

The first part 6 and the second part 8 can for example take the form of two half-shells, for example symmetrical. Alternatively, the first part 6 can be a main body and the second part 8 can be a lid.

In many embodiments, the box 4 is made of an electrically insulating material, for example a thermoset polymer, such as polyamide.

In many embodiments, switching apparatus 2 further includes electrical connection terminals 10, at least one movable electrical contact, a switching mechanism configured to move the movable electrical contact, and arcing chamber 12.

The movable electrical contact (not shown) is movable between an open position and a closed position to, respectively, prevent or allow the flow of electric current between the electrical connection terminals 10. The or each movable electrical contact could be coupled to one or several fixed electrical contacts.

In practice, the switching mechanism (not shown) can be coupled to a trip device configured to detect an electrical fault, such as an overcurrent or a short circuit. The switching mechanism can also be coupled to a control lever accessible to a user from outside the box 4.

Such electromechanical devices are well known and are not described in detail in the following.

The interrupting chamber 12 is configured to extinguish an electric arc which appears between the electrical contacts when they open following a triggering of the device 2 while an electric current is flowing between the connection terminals 10.

The interrupting chamber 12 comprises a stack of metal plates 14 superimposed one above the other in a stacking direction, which here is oriented vertically or essentially vertically when the switching device 2 is in the operating configuration (for example mounted on an electrical panel).

The metal plates 14 are arranged in the stack being spaced apart two by two by a spacing 15.

When an electric arc appears between the electric contacts during the opening of the movable contact, the electric arc is guided towards the stack then is split by the metal plates, which makes it possible to lengthen and thus extinguish the electric arc. .

The metal plates 14 are held in the stack by means of support structures 16, such as side flanges, which are for example made of plastic material, preferably flame-retardant plastic material, for example poly aramid, such as Nomex material. (trademark).

The interrupting chamber 12 can be formed in a dedicated compartment of the casing 4, for example by being delimited by internal walls.

One or more outlet orifices 18 are made in the box 4 and allow the cut-off gases (hot and ionized gases ejected from the box 4 and resulting from the action of the electric arc in the cut-off chamber 12 following the opening of the contacts) from being rejected outside the casing 4 of the switching device 2.

The outlet orifice(s) 18 are, for example, fluidically connected to the outlet of the interrupting chamber 12 by a channel formed in the casing 4.

Guide elements, such as baffles, can be arranged in the channel to regulate the flow of cutoff gas.

Switching device 2 further comprises a separation piece 20 placed at the outlet of arc chute 12, so as to separate the flow of gas exiting from arc chute 12.

Preferably, the separation piece 20 is placed in contact with the stack of metal plates 14, perpendicular to the metal plates, being at least partially inserted into the interstitial spaces 15 between the metal plates of the stack.

In the example of the , the separation piece 20 is illustrated in an exploded view, while on the , the separation piece 20 is illustrated in an operating configuration, assembled with the stack of metal plates 14.

As illustrated on the , the separation piece 20 comprises a main part 22 in the form of a plate and a curved portion 24 in the shape of an L extending perpendicularly with respect to the main part 22.

When the separation piece 20 is in the assembled configuration, the main part 22 is aligned in the direction of the stack of metal plates. In the example illustrated, the main part 22 is aligned vertically or essentially vertically.

The curved L-shaped portion 24 comprises a first flat part which extends perpendicular to the main part 22 and along an edge of the main part 22, and a second plate-shaped part which extends perpendicular to said edge of the main part 22, for example by being arranged horizontally.

The separation piece 20 also comprises a plurality of positioning portions 26 made on one edge of the main part 22.

The positioning portions 26 are configured to be inserted between the metal plates 14 of the stack, for example in the interstitial spaces 15.

For example, the positioning pieces 26 have the shape of a lug, or of a hook, or of a protrusion, or of any other appropriate structure making it possible to prevent a translational movement along the direction of the stack when the piece of separation 20 is inserted into the stack.

Preferably, the separation piece 20 is constructed from an electrically insulating material, such as a thermoformed polymer. However, other materials are possible as an alternative.

In practice, the positioning portions 26 are formed in one piece with the rest of the separation piece 20.

Notably, the separation piece 20 is independent, that is to say it does not form part of the casing 4. In practice, the separation piece 20 can be manufactured independently of the casing 4, then is installed by insertion in the stack.

Figures 4 and 5 show a possible arrangement of the casing 4 and the interrupting chamber 12.

More specifically, the comprises two views showing the respective inner wall of the first housing part 6 and the second housing part 8, respectively.

There schematically represents a cross-sectional view of the separation piece 20 seen from the rear of the interrupting chamber.

In this description, the qualifiers "front" and "rear" applied to the interrupting chamber 12 and to its constituent elements are defined according to the direction of circulation of the interrupting gases (that is to say, from the cutoff 12 to outlet port 18).

In many embodiments, the switching device 2 comprises a grid 30, 32 placed at the output of the stack of metal plates 14.

For example, as clearly visible on the , the grid is at least partly formed by half-bars arranged in the manner of a comb and extending from opposite inner walls of the housing 4. The grid is here placed immediately at the outlet of the stack of metal plates 14, preferably in contact with the stack of plates 14.

For example, a first grid half 30 includes half-bars 34 which extend from an inner wall of the first housing part 6. A second grid half 32 includes half-bars 36 which extend from an internal wall internal part of the second housing part 8.

It is understood that, when the housing 4 is in the assembled configuration, the respective internal walls of the first housing part 6 and of the second housing part 8 are opposite, that is to say that they face each other. Their respective half-bars 34 and 36 are then arranged facing each other.

In some cases, each of the half-bars 34 of the first half-grid 30 may be aligned with the corresponding half-bar 36 of the second half-grid 32.

In other cases, as a variant, the half-bars 34 of the first half of the grid 30 can be offset vertically with respect to the half-bars 36 of the second half of the grid 32.

Preferably, whatever the arrangement of the half-bars, the distal ends of the opposite half-bars 34, 36 delimit a space (here in the form of a vertical slot) into which the main part 22 of the separation piece is inserted, as illustrated by the .

Optionally, the casing parts 6 and/or 8 can include structural and/or positioning elements, such as a baffle 40 to channel the cut-off gases leaving the grid, holding beams 42 perpendicular to the internal walls , to maintain a constant spacing between said internal walls, or else a wall 44 serving to slow down the flow of cut-off gas. These elements can be formed in one piece with one or the other of the first casing part 6 and the second casing part 8. Other embodiments are however possible as a variant.

Thanks to the invention, the addition of the separation piece 20 makes it possible to divide the flow of cutoff gas leaving the arc chute into two independent flows (this flow leaving being typically oriented parallel to the metal plates 14).

This makes it possible to better balance the pressure of the breaking gases and therefore to improve the operation of the breaking chamber 12 and of the switching device 2.

The fact of using an independent separation part 20, separated from the rest of the casing 4, makes it possible to simplify the manufacturing process, since a part having a simple geometry like that of the separation part 20 is less complex and less expensive to produce industrially only a separation piece which would be formed in one piece with the grid or with the housing.

In addition, the separation piece 20 is particularly simple to assemble and easy to put in place, in particular thanks to the positioning portions 26. The guidance (during assembly) and the holding in position of the separation piece over time 20 are improved. In particular, the separation piece 20 makes it possible to better distribute the flow of cut-off gas between the guiding and slowing down elements (such as the wall 44) placed on the internal walls of the casing, and in particular on the first casing part 6. This helps to better balance the cutoff gas flow when releasing pressure during gas ejection.

Many other embodiments are possible.

The embodiments and variants considered above can be combined together to create new embodiments.

Claims (9)

Electric switching device (2), comprising a casing (4) and a breaking chamber (12) housed in the casing, the breaking chamber comprising a stack of metal plates (14), the switching device further comprising a separation piece (20) placed at the outlet of the interrupting chamber, the separation piece being placed in contact with the stack of metal plates, perpendicular to the metal plates, being at least partially inserted in the grid and/or between the metal plates of the stack, so as to separate the flow of gas leaving the interrupting chamber. Electrical switchgear (2) according to claim 1, wherein the separating piece (20) has a main part (22) in the form of a plate, the main part being aligned in the direction of the stack of metal plates (14 ). Electrical switchgear (2) according to any one of the preceding claims, in which the separating part (20) comprises a curved portion (24) in the shape of an L extending perpendicularly with respect to the main part (22). Electrical switchgear (2) according to any one of the preceding claims, in which the separating piece (20) comprises a plurality of positioning portions (26) provided on an edge of the main part, the positioning pieces being configured to be inserted between the metal plates of the stack. Electrical switchgear (2) according to any one of the preceding claims, in which the positioning portions (26) are in the form of a lug. Electrical switchgear (2) according to any one of the preceding claims, in which the positioning portions (26) are formed integrally with the separating part. Electrical switchgear (2) according to any one of the preceding claims, in which the separating piece (20) is formed from an electrically insulating material, such as a thermoformed polymer. Electrical switching device (2) according to any one of the preceding claims, in which the switching device (2) comprises a grid (30, 32) placed at the output of the stack of metal plates (14). Electrical switchgear (2) according to claim 8, wherein the grid (30, 32) is at least partly formed by half-bars (34, 36) extending from interior walls (6, 8) of the casing (4), the distal ends of the opposite half-bars (34, 36) delimiting a space in which the main part (22) of the separating piece (20) is inserted.