FR2461349A1 - IMPROVED CUTTING CHAMBER FOR MULTIPOLAR LOW VOLTAGE CIRCUIT BREAKER WITH MOLDED HOUSING - Google Patents

Abstract

THE INVENTION RELATES TO AN ARC EXTINGUISHING CHAMBER WITH IMPROVED COOLING GAS CUT-OFF. IT INCLUDES A DEIONIZATION DEVICE 40 WITH A POROUS SCREEN 41 HOUSED IN AN EXHAUST PORT 38 OF THE INSULATING BOX 12. THE POROUS SCREEN 41 IS SHAPED FROM AGGLOMERATED BALLS 42 HAVING A DIAMETER OF 0.8MM. INTERSTICES ARE PROVIDED BETWEEN THE BALLS 42 FOR THE PASSAGE OF THE CUT-OFF GAS TO THE EXTERNAL ENVIRONMENT. THE MATERIAL OF THE BALLS IS BASED ON COPPER. APPLICATION: LOW VOLTAGE CIRCUIT BREAKER WITH MOLDED BOX.

Description

The invention relates to an extinction chamber

  arc for low-voltage multi-pole circuit breaker with metal casing

  molded insulating material, comprising, by pole: a pair of fixed and movable separable contacts; a mechanism for actuating the movable contact movable between closing and opening positions;

  - metal plates for cooling the arc drawn between

  said contacts during their separation after triggering the dis-

trunk,

  - an exhaust port of the cutoff gases in the bowl

  tier at the exit of the said room,

  and a deionization device arranged in the vicinity of said ori-

  fice exhaust to cool the vent cutoff to

the external environment.

  According to a known circuit breaker of the kind mentioned, the dis-

  positive deionization includes metal grids or fine mesh screens, especially steel, housed in the orifices

  exhaust. The cut-off gases generated in the chamber of

  during the break are ventilated to the outside environment after passing through the grids playing the role of flame arrester, and it was found that these gases were still strongly ionized at the exit

from the room.

  To improve the cooling of the cut-off gases, other deionization devices have already been proposed, in particular a labyrinth formed by a plurality of offset window screens.

  a reflection grid, cooling tubes, but the

  most importantly these devices do not allow their use

  in compact extinguishing chambers for

  molded thirds. The object of the invention is to avoid the aforementioned drawbacks and to allow the realization of an extinction chamber

  high breaking capacity, equipped with a deionizing device

  improved compact structure for cooling

  effective ventilation of the cutoff gases to the outside environment.

  The extinguishing chamber is characterized in that said deionization device comprises a monoblock screen

  of porous structure formed from agglomerated elements

  between them gaps of passage of cut-off gases to

  the external environment, the constituent material of said elements

  melting point, thermal conductivity and

2 2461349

  high heat density. Each agglomerated element has a

  and 1.5 mm between 0.5 mm / whatever the nature of the material chosen to determine the optimum particle size of said porous screen

  suitable for efficient absorption of heat from

  pure without disturbing their escape to the outside.

  According to one characteristic of the invention, said material

  of the agglomerated elements of the porous screen comprises a metal

  or alloy, especially copper-based.

  According to another characteristic of the invention, said material of the agglomerated elements is non-metallic, in particular a

  refractory ceramic material, or sand-based powder.

  Said elements of the porous screen are constituted by balls or grains agglomerated by any heating method or

  sintering. The balls have substantially the same diameter of

  to provide interstices large enough for the escape

gases.

  Other advantages and features will emerge more clearly from the following description of a mode of implementation.

  of the invention, given by way of nonlimiting example and

  FIG. 1 is a longitudinal sectional view of an arc extinguishing chamber according to the invention, of a molded cased circuit breaker shown partially broken away; Figure 2 is a side view of Figure 1 and shows an outer connection connected to an output range of the center pole;

  FIG. 3 shows in detail the device

of fig. 1.

  With reference to FIGS. 1 to 3, the multipolar low-voltage circuit breaker with casing 12 made of molded insulating material and with a manual control lever 14 comprises, by pole, an arc extinction chamber 16 housed in a lower compartment 18 of the

boot 12.

  Each arc extinction chamber 16 includes a pair

  of separable contacts 20, 22 and a stack of cooling plates 24

  V-notch, extending transversely to the direction of

  extension of the arc pulled between the contacts 20, 22 during their separation after tripping of the circuit breaker. The fixed contact 20 is supported by a conductor 26 in the form of a U-shaped pin,

  positioned on an intermediate wall 27 of the box 12 and in

  electrical connection with an outer 28 connection range. A metal shielding element is inserted between the two

  branches of the driver's pin 26, and is provided with an extension

  32 Playing the end separator r8le. The contact person

  bile 22 is secured to a contact arm 34 associated with a pivoting bar of the actuating mechanism (not shown) common to

  all the poles. A link braid 36 connects the opposite end.

  arm 34 to the thermal and electronic trigger elements

  magnetic (not shown) of each pole. The transverse face of the lower compartment of the casing 12 is provided with an orifice 38 for exhausting the cutoff gases provided at the outlet of each

arc extinction chamber 16.

  According to the invention, a device for deionizing

  gas, designated by the general reference 40 is disposed in each

  exhaust 38 to reduce the external manifestations of the ionized gases in the vicinity of the connections 42 associated with the beaches 28 through efficient cooling of the hot gases to the

  leaving the chamber 16. Each deionization device 40

  It operates with the plates 24 and comprises a block 41 (FIG 3) or parallelepipedal screen of porous structure, formed from balls 42 or agglomerated grains, forming between them gas passage interstices. The material of the balls 42 has both good thermal conductivity and a high heat capacity, and in particular comprises a metal or alloy with a high melting point such as bronze, copper or steel. He appeared on the other hand

  that the choice of the dimensions of the balls 42 or grains was essentially

  damental to determine the optimum particle size of the porous block 41 and obtain an effective absorption of heat at the exit of

  the chamber 16 without interfering with the escape of the gases of cou-

  pure towards the outside environment. This particle size depends on the material

  selected material and the volume of the porous block 41, and it was found during the tests that the diameter of the balls 42 or grains should be between 0.5 mm and 1.5 mm to obtain a correct gas exhaust and an optimum lowering of the temperature of the exit gases. In the embodiment shown, the porous block 41 with dimensions 25 mm × 18 mm and thickness 3.6 mm comprises

  bronze balls 42 having diameters close to 0.8 mm. The opera-

  Agglomeration ration of the balls 42 or grains can be achieved

  by any heating or sintering process well known to the spe-

Specialists.

  According to an alternative embodiment, the porous block 41 may consist of balls 42 or grains of non-metallic material, resistant to high temperatures of the cutting gases, in particular a refractory ceramic material or sand-based powder, and whose dimensions are included in the range

above from 0.5 mm to 1.5 mm.

  An additional screen 44, made of insulating material, is arranged in the exhaust zone of each arc extinguishing chamber 16, in the gap formed between the ends of the plates 24 and the porous block 41. The screen 44 s extends in the direction of the height between the bottom 45 of the casing 12 and the intermediate wall 27, and is pierced with a plurality of holes 46 arranged with respect to the

porous block 41.

  The operation of the deionization device 40

  according to the invention follows from the foregoing description, and it suffices

  made to remember that when cutting the bow in the room

  16, the cut-off gases after passing through the

  notch 44 insulation, are effectively cooled in the porous block

  41 with metal balls 42 and escape to the external environment.

laughing.

  The invention is of course in no way limited to the embodiment more particularly described and shown in the accompanying drawings, but on the contrary it extends to any variant remaining within the framework of mechanical and electrical equivalences, in particular that in which the balls 42 or grains

  porous block 41 would be replaced by other elements

mothers.

Claims (10)

  1. Arc extinguishing chamber for low circuit breaker   multipole voltage with casing made of molded insulating material, comprising   by pole: - a pair of separable contacts fixed and movable, - a mechanism for actuating the movable contact movable between closing and opening positions,   - metal plates for cooling the arc drawn between   said contacts during their separation after triggering the dis- Io junction,   - an exhaust port of the cutoff gases in the bowl   tier at the exit of the said room,   and a deionization device arranged in the vicinity of said ori-   exhaust duct for cooling the vented cutoff gases to the outside environment, characterized in that said deionization device comprises a monobloc screen of porous structure formed from   of agglomerated elements between them gaps of pas-   cutting gases to the external environment, the material con-   of said elements having a melting point, a con-   high thermal conductivity and heat capacity.   Arc extinguishing chamber according to claim 1,   characterized in that each agglomerated element has a   between 0.5 mm and 1.5 mm whatever the nature of the material chosen to determine the optimum particle size of said porous screen suitable for an effective absorption of heat from   cutting gas without hindering their exhaust towards the   TER AL. Arc extinguishing chamber according to claim 2,   characterized in that said material of the agglomerate elements   Res porous screen includes a metal or alloy.   Arc extinguishing chamber according to claim 3,   characterized in that said material is copper-based.   Arc extinguishing chamber according to claim 4,   characterized in that said material is bronze.   Arc extinguishing chamber according to one of the claims   cations 2 to 5, characterized in that said elements ag-   glomerates are constituted by balls having substantially same diameter.   Arc extinguishing chamber according to one of the   cations 2 to 5, characterized in that said elements ag-   Glomerates consist of grains.   8. Arc extinguishing chamber according to any one of   of the preceding claims, characterized by the fact that   said elements of said porous screen are agglomerated by any process heating or sintering.   Arc extinguishing chamber according to claim 8,   characterized in that said material of the agglomerate elements   res is non-metallic, in particular a refractory ceramic material   silted or powder-based sand.   10. Arc extinguishing chamber according to any one of   of the preceding claims, characterized in that   porous screen housed in the exhaust port of the associated pole, is arranged opposite an external connection connected to the beach   corresponding for a connection from the back of the circuit breaker.