EP0468838B1 - Ignition system for a pyrotechnical composition - Google Patents

Ignition system for a pyrotechnical composition Download PDF

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Publication number
EP0468838B1
EP0468838B1 EP91401800A EP91401800A EP0468838B1 EP 0468838 B1 EP0468838 B1 EP 0468838B1 EP 91401800 A EP91401800 A EP 91401800A EP 91401800 A EP91401800 A EP 91401800A EP 0468838 B1 EP0468838 B1 EP 0468838B1
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EP
European Patent Office
Prior art keywords
composition
weight
ignition system
flame
ignition
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EP91401800A
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German (de)
French (fr)
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EP0468838A1 (en
Inventor
René Laurensou
Richard Vineau
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Giat Industries SA
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Giat Industries SA
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42AMMUNITION; BLASTING
    • F42DBLASTING
    • F42D1/00Blasting methods or apparatus, e.g. loading or tamping
    • F42D1/04Arrangements for ignition
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06CDETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C5/00Fuses, e.g. fuse cords
    • C06C5/06Fuse igniting means; Fuse connectors
    • CCHEMISTRY; METALLURGY
    • C06EXPLOSIVES; MATCHES
    • C06CDETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C9/00Chemical contact igniters; Chemical lighters

Definitions

  • the field of the present invention is that of ignition systems for pyrotechnic compositions and in particular for delay pyrotechnic compositions.
  • compositions are generally ignited by means of a composition known as a hot composition (such as a mixture of titanium and boron), itself initiated by a composition sensitive to percussion or to the heating of an electrical conductor.
  • a hot composition such as a mixture of titanium and boron
  • compositions are enclosed in a box whose function is to isolate them from ambient humidity which degrades their characteristics.
  • the casing is closed by a metal sheet called "paillet" (generally aluminum or tin) which is thin enough to be pierced by a striker (see by example patent US4841856 On which or bases the preamble of independent claim 1.
  • a metal sheet generally aluminum or tin
  • the form of the delay component will therefore depend on the final structure of the initiating device, which implies that a modification of the definition of said system will require the delay component to be redesigned.
  • the receptor composition is in all cases another primer which is initiated by the shock resulting from the projection of metal fragments, this shock being able to perfectly initiate the primer through the flake.
  • the hot compositions necessary to ignite the pyrotechnic delays are not sufficiently sensitive to shock to be able to be thus initiated directly, and it will therefore be necessary to provide an additional primer upstream of the hot composition, primer which will be initiated directly by a striker (with the problems of defining the geometry of the delay mentioned above), or through a conduit.
  • the subject of the invention is an ignition system for a pyrotechnic composition
  • a pyrotechnic composition comprising, disposed in a housing, an ignition relay which is in contact with the pyrotechnic composition; it is characterized in that the box is closed by a mesh in contact with a composition sensitive to the flame itself in contact with the ignition relay.
  • the fineness of the mesh of the mesh is less than the particle size of the flame-sensitive composition; thus, it is possible to use a composition that is not very compacted.
  • the flame-sensitive composition comprises a mixture consisting of 25% to 50% by mass of Zirconium and 50% to 75% by mass of Barium Chromate, and preferably is a tablet comprising 37% by mass of Zirconium and 63% by mass of Barium Chromate, the particle size of the mixture being between 40 ⁇ m and 100 ⁇ m.
  • the ignition relay comprises a mixture consisting of 20% to 60% by mass of Zirconium, 30% to 70% by mass of Barium Chromate and 0% to 20% by mass of potassium perchlorate, and preferably the relay is a tablet comprising: 40% by mass of zirconium, 50% by mass of barium chromate and 10% by mass of potassium perchlorate.
  • the ignition system will advantageously apply to the production of a delay cord integrated in a metal sheath.
  • the ignition system will be used in a priming device in which a percussion-sensitive priming composition is connected to the flame-sensitive composition by a conduit.
  • the priming composition sensitive to percussion comprises a tablet of a mixture of 52% by mass of potassium perchlorate, 25% by mass of lead thiocyanate, 13% by mass of antimony sulfide. and 10% by mass of lead tricinate.
  • FIG. 1 represents an ignition system according to the invention associated with a pyrotechnic delay cord and with an ignition device shown diagrammatically,
  • Figure 2 shows the trellis alone.
  • an ignition system 1 is shown integral with a cord 9 containing a pyrotechnic composition with delay 2. It consists of a housing 3 of aluminum alloy, the l 'thickness is of the order of a few tenths of mm, and which is fixed to the cord 9 by notches.
  • an ignition relay 4 which is here a mixture of 40% by mass of Tungsten (W), 50% by mass of Barium Chromate (BaCrO4) and 10% by mass of perchlorate of Potassium (KClO4), the particle size of the components preferably being chosen less than 100 ⁇ m.
  • the previous mass proportions may vary within the following ranges: Tungsten between 20% and 60%, Barium Chronate between 30% and 70%, Potassium perchlorate between 0% and 20%.
  • any other hot composition comprising an oxidizing agent and a reducing agent could be envisaged, such as a mixture of aluminum and copper oxide AlCuO in the proportions by respective masses 20% / 80%, or else a mixture of Zirconium and Lead Chromate in the proportions by respective masses 60% / 40%, or a mixture of Boron and Potassium Nitrate in the proportions by respective masses 60% / 40%.
  • Titanium-Boron TiB
  • TiB Titanium-Boron
  • a flame-sensitive composition 6 which is here a mixture of Zirconium and Barium Chromate in the respective proportions by mass 37% / 63%, with a particle size between 50 ⁇ m and 100 ⁇ m .
  • the proportions by mass may vary within the following ranges:
  • Zircomium between 25% and 50%, Barium chromate between 50% and 75%.
  • composition comprising an oxidizing agent and a reducing agent could be adopted, for example a composition Magnesium, Teflon (registered trademark for Polytetrafluoroethylene), Viton (registered trademark for a copolymer of vinylidene fluoride / hexafluoropropylene), but the criterion for choosing the composition will be its sensitivity to flame.
  • a composition Magnesium, Teflon (registered trademark for Polytetrafluoroethylene), Viton (registered trademark for a copolymer of vinylidene fluoride / hexafluoropropylene), but the criterion for choosing the composition will be its sensitivity to flame.
  • a given composition will be considered to be sensitive to flame if, for ten consecutive tests, it has 100% initiation by the igniter thus described at a distance of at least 470 mm.
  • a composition will be all the more sensitive as it will be weakly compressed, we will preferably adopt a compression ratio between 107 and 8.10 de Pascal.
  • composition of the ignition relay 4 as well as that sensitive to the flame 6 are manufactured by known methods, for example that in which the following phases are found: coating with a binder (for example nitrocellulose) in a solvent, drying , granulation, placement in the housing and compression.
  • a binder for example nitrocellulose
  • a wire mesh 5 is deposited on the composition 6 and the box 3 is closed over the assembly by an annular crimping.
  • the trellis is shown in detail in FIG. 2. It comprises wires 15, of stainless steel, crisscrossed and whose diameter is of the order of a hundredth of a mm.
  • the fineness of the lattice (a), which is defined as the diameter of the largest particle that can pass through the meshes, will be chosen less than the particle size of the mixture, ie here a fineness of 40 ⁇ m.
  • the material of the lattice will be chosen as a function of the desired mechanical strength, the metallic materials, and in particular stainless steel, make it possible to obtain lattices with fine meshes and having a suitable rigidity.
  • the thermal conductivity of the straw by allowing the heat received to be dissipated prevents ignition.
  • the housing 3 is freely adjusted in a bore 16 made in a priming device 11 (not shown in detail).
  • the fineness of the lattice guarantees suitable ignition of the composition even in the case of gas flows at the periphery of the housing 3.
  • a conduit 8 connects the flame-sensitive composition 6 to a priming composition 7 sensitive to percussion and which may be associated with a flame-enhancing composition, the assembly constituting an igniter.
  • a priming composition a tablet of a mixture of potassium perchlorate, lead thiocyamate, antimony sulfide and lead tricinate in the respective proportions by mass 52% ⁇ 20%, 25% ⁇ 10%, 13% ⁇ 10% and 10% ⁇ 10%.
  • the priming composition will combine an oxidant (such as potassium perchlorate), a reducing agent (such as lead thiocyanate), an agent increasing friction (such as Antimony Sulfide), and possibly a sensitizer (such as lead tricinate), the flame-enhancing composition being an oxidizing / reducing composition.
  • an oxidant such as potassium perchlorate
  • a reducing agent such as lead thiocyanate
  • an agent increasing friction such as Antimony Sulfide
  • a sensitizer such as lead tricinate
  • the igniter and the conduit are thus associated with the ignition system previously described to complete the pyrotechnic chain for igniting the delay composition 2 of cord 9.
  • the priming composition 7 is initiated by a striker 14 which moves towards it in the direction F.
  • the duct may have various shapes and profiles, the lattice not isolating the flame-sensitive composition from projections from the igniter.
  • the receiving composition is a composition sensitive to percussion and the conduit is straight so as not to slow down the flow of hot particles impacting the receiving composition.
  • conduits which are not straight the only important parameter will be the length of the conduit.
  • the ignition system will then be designed by varying the power of the igniter 7 (for example by increasing its mass) and / or the sensitivity of the flame-sensitive composition 6 (for example by modifying the compression ratio) .
  • the delay cord 9 of known type comprises for example a composition 2 of tungsten, barium chromate and potassium perchlorate in the respective proportions in the following masses: 30%, 60% and 10% (see for example patent FR2464932 ).
  • This composition 2 is enclosed in a metallic sheath 10, of Lead or Tin, of approximately 3 mm of external diameter.
  • this cord is disposed in a bore 17 arranged in the priming device 11, it carries a detonation relay 12 of known type, for example constituted by a layer of lead azide followed by a layer d 'hexogen.
  • This relay initiates a receiving charge 13 which in turn will initiate an explosive charge, not shown.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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Description

Le domaine de la présente invention est celui des systèmes d'allumage pour les compositions pyrotechniques et en particulier pour les compositions pyrotechniques à retard.The field of the present invention is that of ignition systems for pyrotechnic compositions and in particular for delay pyrotechnic compositions.

De telles compositions sont généralement allumées au moyen d'une composition dite composition chaude (telle un mélange de Titane et de Bore), elle-même initiée par une composition sensible à la percussion ou à l'échauffement d'un conducteur électrique.Such compositions are generally ignited by means of a composition known as a hot composition (such as a mixture of titanium and boron), itself initiated by a composition sensitive to percussion or to the heating of an electrical conductor.

Les compositions sont enfermées dans un boîtier dont la fonction est de les isoler de l'humidité ambiante qui dégrade leurs caractéristiques.The compositions are enclosed in a box whose function is to isolate them from ambient humidity which degrades their characteristics.

Ainsi, dans le cas d'une initiation par percussion, le boîtier est fermé par une feuille métallique appelée "paillet" (généralement de l'aluminium ou de l'étain) qui est suffisamment mince pour pouvoir être percée par un percuteur (voir par exemple le brevet US4841856 Sur lequel ou base le préambule de la revendication indépendante 1.Thus, in the case of an initiation by percussion, the casing is closed by a metal sheet called "paillet" (generally aluminum or tin) which is thin enough to be pierced by a striker (see by example patent US4841856 On which or bases the preamble of independent claim 1.

Lorsque l'on souhaite mettre en place un tel système à retard dans un dispositif d'amorçage non électrique pour un projectile ou une charge militaire, il est indispensable de disposer le système d'allumage en regard d'un percuteur, la sortie du retard devant se trouver en regard de la chaîne pyrotechnique à commander.When it is desired to set up such a delay system in a non-electric ignition device for a projectile or a military charge, it is essential to have the ignition system facing a striker, the output of the delay must be next to the pyrotechnic chain to be controlled.

La forme du composant à retard dépendra donc de la structure finale du dispositif d'amorçage, ce qui implique qu'une modification de la définition dudit système obligera à re-concevoir le composant à retard.The form of the delay component will therefore depend on the final structure of the initiating device, which implies that a modification of the definition of said system will require the delay component to be redesigned.

Il a déjà été prévu dans le cas des dispositifs d'amorçages pour fusées de projectile, de séparer par un conduit l'amorce percutante d'une composition pyrotechnique réceptrice. On se reportera en particulier aux brevets US2730046 et FR2533687.Provision has already been made in the case of priming devices for projectile rockets, to separate the percussive primer from a receiving pyrotechnic composition by a conduit. Reference is made in particular to patents US2730046 and FR2533687.

Cependant, la composition réceptrice est dans tous les cas une autre amorce qui est initiée par le choc résultant de la projection de fragments métalliques, ce choc pouvant parfaitement initier l'amorce au travers du paillet.However, the receptor composition is in all cases another primer which is initiated by the shock resulting from the projection of metal fragments, this shock being able to perfectly initiate the primer through the flake.

Or, les compositions chaudes nécessaires pour allumer les retards pyrotechniques ne sont pas suffisamment sensibles au choc pour pouvoir être initiées ainsi directement, et il sera donc nécessaire de prévoir une amorce supplémentaire en amont de la composition chaude, amorce qui sera initiée directement par un percuteur (avec les problèmes de définition de la géométrie du retard évoqués précédemment), ou par l'intermédiaire d'un conduit.However, the hot compositions necessary to ignite the pyrotechnic delays are not sufficiently sensitive to shock to be able to be thus initiated directly, and it will therefore be necessary to provide an additional primer upstream of the hot composition, primer which will be initiated directly by a striker (with the problems of defining the geometry of the delay mentioned above), or through a conduit.

Dans tous les cas, la sensibilité au choc du système d'allumage se trouve augmentée. Si un conduit est utilisé, il devra être rectiligne afin de ne pas diminuer l'énergie des particules projetées.In all cases, the shock sensitivity of the ignition system is increased. If a duct is used, it must be straight so as not to decrease the energy of the projected particles.

C'est le but de l'invention que de pallier de tels inconvénients en proposant un système d'allumage qui n'est pas sensible aux chocs, et qui peut être initié à distance au moyen d'un inflammateur.It is the object of the invention to overcome such drawbacks by proposing an ignition system which is not sensitive to shocks, and which can be initiated remotely by means of an igniter.

Ainsi, l'invention a pour objet un système d'allumage pour une composition pyrotechnique comprenant, disposé dans un boîtier, un relais d'allumage qui est en contact avec la composition pyrotechnique; il est caractérisé en ce que le boîtier est fermé par un treillis en contact avec une composition sensible à la flamme elle-même en contact avec le relais d'allumage.Thus, the subject of the invention is an ignition system for a pyrotechnic composition comprising, disposed in a housing, an ignition relay which is in contact with the pyrotechnic composition; it is characterized in that the box is closed by a mesh in contact with a composition sensitive to the flame itself in contact with the ignition relay.

Ainsi, la tenue mécanique de la composition est assurée et l'allumage est possible au travers du treillis.Thus, the mechanical strength of the composition is ensured and ignition is possible through the trellis.

De façon préferentielle, la finesse des mailles du treillis est inférieure à la granulométrie de la composition sensible à la flamme; ainsi, il est possible d'utiliser une composition peu compactée.Preferably, the fineness of the mesh of the mesh is less than the particle size of the flame-sensitive composition; thus, it is possible to use a composition that is not very compacted.

La composition sensible à la flamme comprend un mélange constitué par 25% à 50% en masse de Zirconium et 50% à 75% en masse de Chromate de Baryum, et, de préférence est un comprimé comprennant 37% en masse de Zirconium et 63% en masse de Chromate de Baryum, la granulométrie du mélange étant comprise entre 40µm et 100µm.The flame-sensitive composition comprises a mixture consisting of 25% to 50% by mass of Zirconium and 50% to 75% by mass of Barium Chromate, and preferably is a tablet comprising 37% by mass of Zirconium and 63% by mass of Barium Chromate, the particle size of the mixture being between 40 μm and 100 μm.

Selon d'autres caractéristiques, le relais d'allumage comprend un mélange constitué par 20% à 60% en masse de Zirconium, 30% à 70% en masse de Chromate de Baryum et 0% à 20% en masse de perchlorate de Potassium, et de préférence le relais est un comprimé comprennant: 40% en masse de Zirconium, 50% en masse de Chrromate de Baryum et 10% en masse de perchlorate de Potassium.According to other characteristics, the ignition relay comprises a mixture consisting of 20% to 60% by mass of Zirconium, 30% to 70% by mass of Barium Chromate and 0% to 20% by mass of potassium perchlorate, and preferably the relay is a tablet comprising: 40% by mass of zirconium, 50% by mass of barium chromate and 10% by mass of potassium perchlorate.

Le système d'allumage s'appliquera avantageusement à la réalisation d'un cordeau retard intégré dans une gaine métallique.The ignition system will advantageously apply to the production of a delay cord integrated in a metal sheath.

Le système d'allumage s'emploira dans un dispositif d'amorçage dans lequel une composition d'amorçage sensible à la percussion est reliée à la composition sensible à la flamme par un conduit.The ignition system will be used in a priming device in which a percussion-sensitive priming composition is connected to the flame-sensitive composition by a conduit.

De façon préférentielle, la composition d'amorçage sensible à la percussion comprend un comprimé d'un mélange de 52% en masse de perchlorate de Potassium, de 25% en masse de Thiocyanate de Plomb, de 13% en masse de Sulfure d'Antimoine et de 10% en masse de Tricinate de Plomb.Preferably, the priming composition sensitive to percussion comprises a tablet of a mixture of 52% by mass of potassium perchlorate, 25% by mass of lead thiocyanate, 13% by mass of antimony sulfide. and 10% by mass of lead tricinate.

L'invention sera mieux comprise à la lecture de la description d'un mode particulier de réalisation, description faite en référence aux dessins annexés dans lesquels:The invention will be better understood on reading the description of a particular embodiment, description made with reference to the accompanying drawings in which:

La figure 1 représente un système d'allumage selon l'invention associé à un cordeau à retard pyrotechnique et à un dispositif d'amorçage représenté schématiquement,FIG. 1 represents an ignition system according to the invention associated with a pyrotechnic delay cord and with an ignition device shown diagrammatically,

La figure 2 montre le treillis seul.Figure 2 shows the trellis alone.

En se reportant à la figure 1, un système d'allumage 1 selon l'invention est représenté solidaire d'un cordeau 9 contenant une composition pyrotechnique à retard 2. Il se compose d'un boîtier 3 en alliage d'alluminium, dont l'épaisseur est de l'ordre de quelques dixièmes de mm, et qui est fixé sur le cordeau 9 par des crantages.Referring to Figure 1, an ignition system 1 according to the invention is shown integral with a cord 9 containing a pyrotechnic composition with delay 2. It consists of a housing 3 of aluminum alloy, the l 'thickness is of the order of a few tenths of mm, and which is fixed to the cord 9 by notches.

A l'intérieur du boîtier est disposé un relais d'allumage 4 qui est ici un mélange de 40% en masse de Tungstène (W), de 50% en masse de Chromate de Baryum (BaCrO4) et de 10% en masse de perchlorate de Potassium (KClO4), la granulométrie des composants étant de préférence choisie inférieure à 100 µm.Inside the housing is an ignition relay 4 which is here a mixture of 40% by mass of Tungsten (W), 50% by mass of Barium Chromate (BaCrO4) and 10% by mass of perchlorate of Potassium (KClO4), the particle size of the components preferably being chosen less than 100 μm.

Les proportions en masses précédentes pourront varier dans les fourchettes suivantes:
   Tungstène entre 20% et 60%, Chronate de Baryum entre 30% et 70%, perchlorate de Potassium entre 0% et 20%.
The previous mass proportions may vary within the following ranges:
Tungsten between 20% and 60%, Barium Chronate between 30% and 70%, Potassium perchlorate between 0% and 20%.

Toute autre composition chaude comprenant un oxydant et un réducteur pourrait être envisagée, tel un mélange d'alluminium et d'oxyde de cuivre AlCuO dans les proportions en masses respectives 20%/80%, ou encore un mélange de Zirconium et de Chromate de Plomb dans les proportions en masses respectives 60%/40%, ou encore un mélange de Bore et de Nitrate de Potassium dans les proportions en masses respectives 60%/40%.Any other hot composition comprising an oxidizing agent and a reducing agent could be envisaged, such as a mixture of aluminum and copper oxide AlCuO in the proportions by respective masses 20% / 80%, or else a mixture of Zirconium and Lead Chromate in the proportions by respective masses 60% / 40%, or a mixture of Boron and Potassium Nitrate in the proportions by respective masses 60% / 40%.

On pourrait également utiliser une composition intermétallique, telle le Titane-Bore (TiB). Le choix des caractéristiques de cette composition chaude du relais d'allumage 4 dépendra essentiellement du type de composition pyrotechnique retard à allumer.One could also use an intermetallic composition, such as Titanium-Boron (TiB). The choice of the characteristics of this hot composition of the ignition relay 4 will essentially depend on the type of delay pyrotechnic composition to be ignited.

L'exemple précédent (W/BaCrO4/KClO4) est particulièrement bien adapté au retard pyrotechnique qui sera décrit par la suite.The previous example (W / BaCrO4 / KClO4) is particularly well suited to the pyrotechnic delay which will be described later.

En contact avec le relais d'allumage est disposée une composition sensible à la flamme 6, qui est ici un mélange de Zirconium et de Chromate de Baryum dans les proportions respectives en masses 37%/63%, avec une granulométrie comprise entre 50µm et 100µm.In contact with the ignition relay is arranged a flame-sensitive composition 6, which is here a mixture of Zirconium and Barium Chromate in the respective proportions by mass 37% / 63%, with a particle size between 50 μm and 100 μm .

Les proportions en masses pourront varier dans les fourchettes suivantes:The proportions by mass may vary within the following ranges:

Zircomium entre 25% et 50%, Chromate de Baryum entre 50% et 75%.Zircomium between 25% and 50%, Barium chromate between 50% and 75%.

Toute autre composition comprenant un oxydant et un reducteur pourrait être adoptée, par exemple une composition Magnésium, Teflon (marque déposée pour le Polytétrafluoréthylène), Viton (marque déposée pour un copolymère de fluorure de vinylidène/hexafluoropropylène), mais le critère de choix de la composition sera sa sensibilité à la flamme.Any other composition comprising an oxidizing agent and a reducing agent could be adopted, for example a composition Magnesium, Teflon (registered trademark for Polytetrafluoroethylene), Viton (registered trademark for a copolymer of vinylidene fluoride / hexafluoropropylene), but the criterion for choosing the composition will be its sensitivity to flame.

Cette dernière sera appréciée par exemple au moyen du test standardisé par le Groupement Français d'étude des modes opératoires (GEMO) sous la référence FA505A1.The latter will be assessed for example by means of the standardized test by the French Group for the study of operating modes (GEMO) under the reference FA505A1.

Ce test est le suivant:

  • on utilise une colonne permettant de régler la distance entre un inflammateur de référence et une composition à tester,
  • l'inflammateur de référence comprend 0,034 gramme d'une composition qui est un mélange dans les proportions en masses de 15% de Silicure de Calcium, 17% de Sulfure d'antimoine, 30% de Nitrate de Baryum, 35% de Styphnate de plomb et 3% de tétrazène, l'ensemble étant comprimé à 10⁸ Pascal,
  • l'inflammateur est initié par une percussion par écrasement,
  • la composition à tester est disposée en vrac dans une coupelle.
This test is as follows:
  • a column is used to adjust the distance between a reference igniter and a composition to be tested,
  • the reference igniter comprises 0.034 grams of a composition which is a mixture in the proportions by mass of 15% of calcium silicide, 17% of antimony sulphide, 30% of barium nitrate, 35% of lead styphnate and 3% tetrazene, the whole being compressed at 10⁸ Pascal,
  • the igniter is initiated by crushing percussion,
  • the composition to be tested is placed in bulk in a dish.

On considérera une composition donnée comme sensible à la flamme si, pour dix essais consécutifs, elle présente 100% d'initiation par l'inflanmateur ainsi décrit à une distance d'au moins 470 mm.A given composition will be considered to be sensitive to flame if, for ten consecutive tests, it has 100% initiation by the igniter thus described at a distance of at least 470 mm.

Il sera possible de doser la sensibilité en jouant sur le taux de compression de la composition. Une composition sera d'autant plus sensible qu'elle sera faiblement comprimée, on adoptera de préférence un taux de compression compris entre 10⁷ et 8.10⁷ Pascal .It will be possible to adjust the sensitivity by adjusting the compression ratio of the composition. A composition will be all the more sensitive as it will be weakly compressed, we will preferably adopt a compression ratio between 10⁷ and 8.10 de Pascal.

La composition du relais d'allumage 4 ainsi que celle sensible à la flamme 6 sont fabriquées par des procédés connus, par exemple celui dans lequel on trouve les phases suivantes: enrobage par un liant (par exemple de la nitrocellulose) dans un solvant, séchage, granulation, mise en place dans le boîtier et compression.The composition of the ignition relay 4 as well as that sensitive to the flame 6 are manufactured by known methods, for example that in which the following phases are found: coating with a binder (for example nitrocellulose) in a solvent, drying , granulation, placement in the housing and compression.

Un treillis métallique 5 est déposé sur la composition 6 et le boîtier 3 est refermé sur l'ensemble par un sertissage annulaire.A wire mesh 5 is deposited on the composition 6 and the box 3 is closed over the assembly by an annular crimping.

Le treillis est représenté en détail sur la figure 2. Il comporte des fils 15, en acier inoxydable, entrecroisés et dont le diamètre est de l'ordre du centième de mm. La finesse du treillis (a), qui est définie comme le diamètre de la plus grosse particule pouvant passer au travers des mailles, sera choisie inférieure à la granulométrie du mélange, soit ici une finesse de 40µm.The trellis is shown in detail in FIG. 2. It comprises wires 15, of stainless steel, crisscrossed and whose diameter is of the order of a hundredth of a mm. The fineness of the lattice (a), which is defined as the diameter of the largest particle that can pass through the meshes, will be chosen less than the particle size of the mixture, ie here a fineness of 40 μm.

L'intérêt d'une telle disposition est de permettre un contact direct entre une flamme et la composition 6 à travers les mailles du treillis sans nuire à la tenue mécanique du composant, qui pourrait éventuellement même être non compacté.The advantage of such an arrangement is that it allows direct contact between a flame and the composition 6 through the meshes of the lattice without harming the mechanical strength of the component, which could possibly even be uncompacted.

Le matériau du treillis sera chosi en fonction de la résistance mécanique souhaitée, les matériaux métalliques, et en particulier l'acier inoxydable, permettent d'obtenir des treillis aux mailles fines et présentant une rigidité convenable.The material of the lattice will be chosen as a function of the desired mechanical strength, the metallic materials, and in particular stainless steel, make it possible to obtain lattices with fine meshes and having a suitable rigidity.

A titre comparatif une composition identique, enfermée dans un boîtier identique fermé par un paillet d'alluminium de 0,03 mm d'épaisseur, n'est par allumée par la flamme.By way of comparison, an identical composition, enclosed in an identical housing closed by an aluminum pellet of 0.03 mm thick, is not ignited by the flame.

En effet, la conductibilité thermique du paillet en permettant de dissiper la chaleur reçue interdit tout allumage.Indeed, the thermal conductivity of the straw by allowing the heat received to be dissipated prevents ignition.

Dans le mode d'application décrit ici, le boîtier 3 est ajusté de façon libre dans un alésage 16 réalisé dans un dispositif d'amorçage 11 (non représenté en détail).In the application mode described here, the housing 3 is freely adjusted in a bore 16 made in a priming device 11 (not shown in detail).

C'est là un autre avantage présenté par l'invention.This is another advantage presented by the invention.

Ainsi, il n'est pas indispensable d'assurer un confinement, la finesse du treillis garantit un allumage convenable de la composition même dans le cas d'écoulements des gaz à la périphérie du boîtier 3.Thus, it is not essential to ensure confinement, the fineness of the lattice guarantees suitable ignition of the composition even in the case of gas flows at the periphery of the housing 3.

Un conduit 8 relie la composition sensible à la flamme 6 à une composition d'amorçage 7 sensible à la percussion et qui pourra être associée à une composition renforcatrice de flamme, l'ensemble constituant un inflammateur.A conduit 8 connects the flame-sensitive composition 6 to a priming composition 7 sensitive to percussion and which may be associated with a flame-enhancing composition, the assembly constituting an igniter.

On pourra par exemple utiliser comme composition d'amorçage un comprimé d'un mélange de perchlorate de Potassium, de Thiocyamate de Plomb, de Sulfure d'Antimoine et de Tricinate de Plomb dans les proportions respectives en masses 52%±20%, 25%±10%, 13%±10% et 10%±10%.It is possible, for example, to use as a priming composition a tablet of a mixture of potassium perchlorate, lead thiocyamate, antimony sulfide and lead tricinate in the respective proportions by mass 52% ± 20%, 25% ± 10%, 13% ± 10% and 10% ± 10%.

Et comme composition renforcatrice de flamme, un mélange de Zirconium et de Chromate de Plomb dans les proportions en masses respectives 60%±10%, 40%±10%.And as flame-enhancing composition, a mixture of Zirconium and Lead Chromate in the proportions by respective masses 60% ± 10%, 40% ± 10%.

Généralement et d'une façon connue, la composition d'amorçage associera un oxydant (tel le perchlorate de Potassium), un reducteur (tel le Thiocyanate de Plomb), un agent augmentant la friction (tel le Sulfure d'Antimoine), et éventuellement un sensibilisant (tel le Tricinate de Plomb), la composition renforcatrice de flamme étant une composition oxydant/réducteur.Generally and in a known manner, the priming composition will combine an oxidant (such as potassium perchlorate), a reducing agent (such as lead thiocyanate), an agent increasing friction (such as Antimony Sulfide), and possibly a sensitizer (such as lead tricinate), the flame-enhancing composition being an oxidizing / reducing composition.

L'inflammateur et le conduit s'associent ainsi au système d'allumage précédemment décrit pour compléter la chaîne pyrotechnique d'allumage de la composition à retard 2 du cordeau 9.The igniter and the conduit are thus associated with the ignition system previously described to complete the pyrotechnic chain for igniting the delay composition 2 of cord 9.

La composition d'amorçage 7 est initiée par un percuteur 14 qui se déplace vers elle dans la direction F.The priming composition 7 is initiated by a striker 14 which moves towards it in the direction F.

On voit qu'il est possible grâce au système d'allumage selon l'invention d'éloigner la composition à retard du mécanisme de percussion.We see that it is possible thanks to the ignition system according to the invention to move the delay composition away from the percussion mechanism.

Il est ainsi possible avec l'inflammateur décrit ci-dessus associé à la composition sensible à la flamme Zirconium 37% - Chromate de Baryum 63%, de disposer un conduit d'une longueur développée de l'ordre de 20 mm entre l'inflammateur et le treillis.It is thus possible with the igniter described above associated with the flame-sensitive composition Zirconium 37% - Barium chromate 63%, to have a conduit with a developed length of the order of 20 mm between the igniter and the trellis.

Le conduit pourra présenter des formes et des profils variés, le treillis n'isolant pas la composition sensible à la flamme des projections issues de l'inflammateur.The duct may have various shapes and profiles, the lattice not isolating the flame-sensitive composition from projections from the igniter.

Comme cela a déjà été noté dans le préambule, dans les dispositifs connus comportant des conduits, la composition réceptrice est une composition sensible à la percussion et le conduit est rectiligne de façon à ne pas freiner le flux de particules chaudes venant impacter la composition réceptrice.As already noted in the preamble, in the known devices comprising conduits, the receiving composition is a composition sensitive to percussion and the conduit is straight so as not to slow down the flow of hot particles impacting the receiving composition.

Avec l'invention, il est possible de définir des conduits qui ne sont pas rectilignes, le seul paramètre important sera la longueur du conduit.With the invention, it is possible to define conduits which are not straight, the only important parameter will be the length of the conduit.

Le plus souvent la longueur de conduit sera imposée par la définition du dispositif d'amorçage.Most often the length of conduit will be imposed by the definition of the priming device.

On concevra alors le système d'allumage en jouant sur la puissance de l'inflammateur 7 (par exemple en augmentant sa masse) et/ou sur la sensibilité de la composition sensible à la flamme 6 (par exemple en modifiant le taux de compression).The ignition system will then be designed by varying the power of the igniter 7 (for example by increasing its mass) and / or the sensitivity of the flame-sensitive composition 6 (for example by modifying the compression ratio) .

Le cordeau à retard 9, de type connu comprend par exemple une composition 2 de tungstène, de Chromate de Baryum et de perchlorate de Potassium dans les proportions respectives en masses suivantes: 30%, 60% et 10% (voir par exemple le brevet FR2464932). Cette composition 2 est enfermée dans une gaine métallique 10, de Plomb ou d'Etain, d'environ 3 mm de diamètre externe.The delay cord 9, of known type comprises for example a composition 2 of tungsten, barium chromate and potassium perchlorate in the respective proportions in the following masses: 30%, 60% and 10% (see for example patent FR2464932 ). This composition 2 is enclosed in a metallic sheath 10, of Lead or Tin, of approximately 3 mm of external diameter.

L'autre extrémité de ce cordeau est disposée dans un alésage 17 aménagé dans le dispositif d'amorçage 11, elle porte un relais de détonation 12 de type connu, par exemple constitué par une couche d'azoture de Plomb suivie d'une couche d'hexogène.The other end of this cord is disposed in a bore 17 arranged in the priming device 11, it carries a detonation relay 12 of known type, for example constituted by a layer of lead azide followed by a layer d 'hexogen.

Ce relais vient initier une charge réceptrice 13 qui initiera à son tour une charge explosive non représentée.This relay initiates a receiving charge 13 which in turn will initiate an explosive charge, not shown.

Il est bien entendu possible d'adapter le système d'allumage selon l'invention à un mode d'initiation électrique en remplaçant l'inflammateur à percussion 7 par un inflammateur à initiation électrique (fil chaud ou fil explosé), les autres éléments du système d'allumage étant inchangés.It is of course possible to adapt the ignition system according to the invention to an electric initiation mode by replacing the percussion igniter 7 with an electric initiation igniter (hot wire or exploded wire), the other elements of the ignition system being unchanged.

Il est possible également d'adapter le système d'allumage selon l'invention à l'allumage d'une autre composition pyrotechnique que celles à retard par exemple à une composition génératrice de gaz.It is also possible to adapt the ignition system according to the invention to the ignition of another pyrotechnic composition than those with a delay, for example to a gas-generating composition.

Claims (10)

  1. The ignition system (1) for a pyrotechnic composition comprising, placed in a housing (3), an ignition relay (4) which is in contact with the pyrotechnic composition (2), characterized in that the housing (3) is closed by a lattice (5) in contact with a flame-sensitive composition (6) itself in contact with the ignition relay (4).
  2. Ignition system according to Claim 1, characterized in that the fineness (a) of the meshes of the lattice (5) is finer than the grain size distribution of the flame-sensitive composition (6).
  3. Ignition system according to Claim 2, characterized in that the flame-sensitive composition (6) includes a mixture consisting of 25 to 50% by weight of zirconium, and 50 to 75% by weight of barium chromate.
  4. Ignition system according to Claim 3, characterized in that the flame-sensitive composition (6) is a compact containing 37% by weight of zirconium and 63% by weight of barium chromate.
  5. Ignition system according to Claim 4, characterized in that the grain size distribution of the flame-sensitive composition (6) ranges between 40 and 100 µm.
  6. Ignition system according to one of Claims 3 to 5, characterized in that the ignition relay (4) contains a mixture consisting of 20 to 60% by weight of zirconium, 30 to 70% by weight of barium chromate, and 0 to 20% by weight of potassium perchlorate.
  7. Ignition system according to Claim 6, characterized in that the ignition relay (4) is a compact containing 40% by weight of zirconium 50% by weight of barium chromate, and 10% by weight of potassium perchlorate.
  8. Application of the ignition system according to one of Claims 1 to 7 to the preparation of a delayed action fuse (9) incorporated in a metal sleeve (10).
  9. Application of the ignition system according to one of Claims 1 to 7 to a detonator (11) in which a detonating composition sensitive to percussion (7) is connected to the flame-sensitive composition (6) by a pipe (8).
  10. Detonator according to Claim 9, characterized in that the detonating composition sensitive to percussion (7) comprises a compact of a mixture of 52% by weight of potassium perchlorate, 25% by weight of lead thiocyanate, 3% by weight of antimony sulfide, and 10% by weight of lead tricinate.
EP91401800A 1990-07-27 1991-07-02 Ignition system for a pyrotechnical composition Expired - Lifetime EP0468838B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9009604 1990-07-27
FR9009604A FR2665254B1 (en) 1990-07-27 1990-07-27 IGNITION SYSTEM FOR A PYROTECHNIC COMPOSITION.

Publications (2)

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EP0468838A1 EP0468838A1 (en) 1992-01-29
EP0468838B1 true EP0468838B1 (en) 1994-11-30

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EP91401800A Expired - Lifetime EP0468838B1 (en) 1990-07-27 1991-07-02 Ignition system for a pyrotechnical composition

Country Status (6)

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US (1) US5147976A (en)
EP (1) EP0468838B1 (en)
DE (1) DE69105393T2 (en)
FR (1) FR2665254B1 (en)
GR (1) GR3015175T3 (en)
IL (1) IL98954A (en)

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US5831207A (en) * 1996-10-30 1998-11-03 Breed Automotive Technology, Inc. Autoignition composition for an airbag inflator
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US6021715A (en) * 1997-05-02 2000-02-08 The Ensign-Bickford Company Manifold for coupling with a tube and method thereof
US6125762A (en) * 1997-07-03 2000-10-03 The Ensign-Bickford Company Flat-form separation devices
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FR2776656B1 (en) * 1998-03-30 2000-04-28 Giat Ind Sa METHOD FOR MANUFACTURING AN OBJECT FROM A GRANULAR MATERIAL, IGNITION TUBE AND PROPULSIVE CHARGE OBTAINED WITH SUCH A METHOD
WO2001029499A1 (en) * 1999-10-20 2001-04-26 Chemical Holdings Int. Ltd. A blast initiation system
US20080217893A1 (en) * 2004-06-17 2008-09-11 Nof Corporation Firing Agent for Gas Generating Device
JP4473818B2 (en) * 2005-12-28 2010-06-02 昭和金属工業株式会社 Initiator igniter, method for producing the same, and method for producing initiator using the same
US11713142B2 (en) * 2017-12-01 2023-08-01 Ensign-Bickford Aerospace & Defense Comany Separation device assemblies
JP2023096436A (en) * 2021-12-27 2023-07-07 日本化薬株式会社 Ignition charge and igniter containing the same

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RU2719830C2 (en) * 2018-07-31 2020-04-23 федеральное государственное бюджетное образовательное учреждение высшего образования "Самарский государственный технический университет" Pyrotechnical composition

Also Published As

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DE69105393T2 (en) 1995-05-04
EP0468838A1 (en) 1992-01-29
IL98954A (en) 1996-01-19
DE69105393D1 (en) 1995-01-12
IL98954A0 (en) 1992-07-15
FR2665254A1 (en) 1992-01-31
FR2665254B1 (en) 1992-10-16
US5147976A (en) 1992-09-15
GR3015175T3 (en) 1995-05-31

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