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WO2006051199A1 - Method of producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition inside an initiator, and initiator thus obtained - Google Patents

Method of producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition inside an initiator, and initiator thus obtained Download PDF

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Publication number
WO2006051199A1
WO2006051199A1 PCT/FR2005/002759 FR2005002759W WO2006051199A1 WO 2006051199 A1 WO2006051199 A1 WO 2006051199A1 FR 2005002759 W FR2005002759 W FR 2005002759W WO 2006051199 A1 WO2006051199 A1 WO 2006051199A1
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WO
WIPO (PCT)
Prior art keywords
bridge
electrothermal
primary composition
initiator
electrical
Prior art date
Application number
PCT/FR2005/002759
Other languages
French (fr)
Inventor
Stéphane Phelep
Thérèse Nguyen
Original Assignee
Davey Bickford
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Davey Bickford filed Critical Davey Bickford
Priority to DE602005007054T priority Critical patent/DE602005007054D1/en
Priority to EP05814875A priority patent/EP1809980B1/en
Publication of WO2006051199A1 publication Critical patent/WO2006051199A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
    • F42B3/00—Blasting cartridges, i.e. case and explosive
    • F42B3/10—Initiators therefor
    • F42B3/195—Manufacture
    • F42B3/198—Manufacture of electric initiator heads e.g., testing, machines
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B21/00—Apparatus or methods for working-up explosives, e.g. forming, cutting, drying
    • C06B21/0033—Shaping the mixture
    • C06B21/005—By a process involving melting at least part of the ingredients
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
    • C06C7/00—Non-electric detonators; Blasting caps; Primers
    • C06C7/02—Manufacture; Packing

Definitions

  • the present invention relates to a method for producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition within an electro-pyrotechnic initiator as well as the initiator obtained by the method. It has applications in the field of pyrotechnics in which it causes the firing of charges (explosive, fuzing, incendiary or other) through an electrical signal.
  • Electro-pyrotechnic initiators are devices whose function is to transform an electrical type input signal into a pyrotechnic effect. These devices make it possible to generate effects of flame, incandescent particles, gases or others; these effects may possibly be combined according to the case.
  • the initiators allow, for example, the priming of slaughter explosives in the industrial field of quarry and public works mines, the ignition of gas generators for automotive safety (passive protection systems of the pre-tensioning type of belts, pyrotechnic reels , airbags, etc.), the activation of pyromechanisms or the ignition of missile or rocket type devices.
  • the electropyrotechnic initiators comprise an electrothermal bridge for supplying heat (temperature rise) under the effect of an electric current to a primary composition which, under the effect of heat, is brought into a reaction. combustible and / or explosive decomposition.
  • the transfer of heat between the electrothermal bridge and the primary composition can be effected, depending on the case, by conduction or thermal convection.
  • the case of thermal conduction is well known and can. be modeled according to the model. djt from Rosenthal.
  • So-called "hot wire" initiators are known which are electrothermal bridges of metal filament type generally made with metal alloys but sometimes with a pure metal.
  • Other initiators include electrothermal bridges of the type of layers (films) or strips that can be pure or non-metallic (alloys), or even semiconductors.
  • the state of the interface between the electrothermal bridge and the primary composition can significantly influence the characteristics of the initiator, in particular with regard to the trip thresholds (electrical energy level causing the decomposition of the primary composition), their speed (speed of transfer of heat from the bridge to the composition), their homogeneity (all the initiators of a batch have substantially the same characteristics).
  • initiators Two major families of initiators can be distinguished according to the manner of obtaining the pyrotechnic interface between the electrothermal bridge and the primary composition: the initiators of "dry compressed” technology and the initiators of "quenched” technology. or wet drop.
  • the type of hardened or wet-drop type technology has certain advantages, particularly in terms of safety of implementation. It is now well known and it generally uses primary compositions based on lead tri-nitro-resorcinate which are, however, expected to disappear in the future because of the presence of lead. In addition to the fact that not all available primary compositions can be put into a form that allows the implementation of wet technology, the latter is not conducive to obtaining pyrotechnic reaction thresholds optimized both in terms of reaction rate (transfer time of the thermal effect of the bridge electrothermal to the primary composition) than reproducibility (levels of predictable normal variations).
  • the main advantage of the dry compressed technology is that it allows optimization (minimization) of the heat transfer rate between the electrothermal bridge heated under the effect of the electric firing signal and the primary composition. Indeed, the compression of the primary composition provides a better "intimacy" (contact) of it with the bridge. Electrothermal. However, this technique is more restrictive from the point of view of safety and it can not use a primary composition that needs air for the decomposition to be done satisfactorily.
  • the present invention proposes a method that can be used both with a wet or a dry technique, whatever the type of electrothermal bridge (wire, layer or strip in particular) and which makes it possible to improve the contact between the primary composition and the bridge. in particular to improve the triggering / firing (speed increase and reproducibility enhancement) qualities of the initiator.
  • the proposed method can be described electrothermal finish of pyroelectric interface and it consists in outline to implement a primary composition with thermoplastic qualities (softening and becoming plastic or fluid under the effect of an increase in temperature ) and to heat the thermal bridge of the initiator without, however, the thermal bridge is degraded, so as to temporarily achieve the softening / plasticity / fluidity (these terms being equivalent here) of the primary composition at least in the environment close to the thermal bridge while not causing the decomposition reaction of said composition (no ignition).
  • the duration of the maintenance of heating of the electrothermic bridge is adapted to the importance of the softening obtained by said heating so that the primary composition is rearranged around the electrothermal bridge and allows an intimate and permanent contact of the primary composition with the electrothermal bridge.
  • the heating and / or the composition is such that the composition becomes fluid so that the finish is relatively short in time, a composition simply softened or plasticized taking more time for rearrangement. It is understood that outside this finish, under normal environmental conditions, the composition is essentially solid.
  • the invention therefore relates to a method for producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition within an electro-pyrotechnic initiator, the initiator being intended to produce a pyrotechnic effect when a higher electrical energy at a threshold of electrical trip energy is sent into the electrothermal bridge.
  • a primary composition which has thermoplastic properties is used, the electrothermal bridge and the thermoplastic-containing primary composition are assembled in the initiator and electrical softening energy is sent into the electrothermal bridge which causes heating. and a softening of the primary composition at least in its part in contact with the electrothermal bridge, the electrical softening energy being of a level below the electric threshold of triggering energy.
  • the assembly of the electrothermal bridge and of the primary composition is carried out by the dry route in compressing the composition in air or in a controlled atmosphere
  • the assembly of the electrothermal bridge and of the primary composition is carried out by wet process by dipping or producing a drop in the air or in a controlled atmosphere,
  • the primary composition at a firing temperature of approximately greater than 300 ° and preferably approximately between 300 ° and 500 ° C.
  • the electrothermal bridge is brought to a temperature of between 150 ° and 250 °, said bridge being made to support such a temperature without degradation;
  • the thermoplastic properties of the primary composition are obtained by the use of a thermoplastic binder at within the composition,
  • a binder based on polybutadiene is used, preferably a fluorinated binder is used,
  • At least one electrical parameter of said electrothermal bridge is monitored which is the electrical resistance
  • the temperature of said electrothermal bridge is estimated by measuring the electrical resistance of said bridge as a function of the energy, at least a first a prior measurement of resistance being made at a reduced level of electrical energy such that it does not cause a significant rise in the temperature of said bridge,
  • the electrical softening energy corresponds to a direct current
  • the electrical softening energy corresponds to an alternating current
  • the electrical softening energy corresponds to a low frequency alternating current of approximately 50 Hz or 60 Hz or their multiples up to three times,
  • the electrical softening energy corresponds to a high frequency alternating current greater than or equal to 100KHz 1
  • the electrical softening energy corresponds to a combination of a direct and alternating current
  • the heating is progressive, (we gradually increase the energy in the electrothermal bridge)
  • the initiator is vibrated
  • the composition is compressed while sending the electric softening energy in the electrothermal bridge to cause heating and softening.
  • the invention also relates to a device of the electro-pyrotechnic initiator type comprising an electro-pyrotechnic interface between an electrothermal bridge and a primary composition, the initiator being intended to produce a pyrotechnic effect when an electrical energy greater than a threshold of electrical trip energy is sent into the electrothermal bridge.
  • the primary composition has thermoplastic properties and is obtained according to one or more of the preceding characteristics.
  • the trigger electric energy threshold may be different between the same initiator before and after the implementation of the method since the functional contact between the electrothermal bridge and the primary composition of the interface is improved. It is therefore understood that the electrical softening energy that is sent is of a level below the threshold of the lowest electric trigger energy, that is to say that which is normally obtained after the implementation of the method .
  • the process is carried out during the manufacture of the initiator and initiators which have already undergone the process of the invention are delivered. It is envisaged, however, that the method is implemented in the field before use (firing). In the latter case it is even envisaged to put the primary composition in a state of softening just before firing (whether or not the process has already been implemented on the initiator). It is understood that these possibilities in the field where generally several initiators are used, require very specific conditions to act precisely on each of the initiators, the paralleling or series on the same command line firing making this possibility more difficult.
  • the method allows in a single operation, in addition to improving the interface, a quality control of the electrothermal bridge because it is possible to measure the electrical characteristics, including the electrical resistance, of the electrothermal bridge during operation. sending the heating energy for softening the primary composition.
  • FIG. 1 which represents in schematic section an initiator just made before implementing the method of the invention
  • Figure 2 which shows a schematic sectional view of an initiator in which electrical softening energy is injected
  • Figure 3 which shows in schematic section an initiator obtained after implementation of the method of the invention.
  • the primary composition generally comprises grains of heat sensitive materials (those that make a reaction) which are bonded to each other by at least one binder.
  • the thermoplastic properties of the primary composition are then given by the binder which has such properties.
  • the invention by a controlled and controlled heating of the bridge and the adjacent primary composition, makes it possible to obtain intimate and final contact (the softening disappears once the heating is removed and the composition decreases in temperature) of the grains. with the electrothermal bridge.
  • an electro-pyrotechnic initiator whose primary composition is based on a thermoplastic binder is subjected to an electrical stimulus calibrated so as to obtain locally at the interface between the electrothermal bridge and the primary composition a sufficient heating, to ensure an intimate and permanent contact of the primary composition with the bridge. Because of this better contact, the firing characteristics and their reproducibility are improved, the initiator is less likely to see its characteristics evolve following shocks, manipulations, placement in deleterious environments (humidity in particular).
  • Such a method is possible in the case of primary compositions containing in their formulation a proportion of thermoplastic binder but also in the case of intrinsically thermoplastic primary compositions.
  • Many pyrotechnic compositions used in pyrotechnic applications include binders. thermoplastics.
  • thermoplastic binder By way of example, mention may in particular be made of fluorinated binders such as VITON®.
  • fluorinated binders such as VITON®.
  • VITON® fluorinated binders
  • the binders are preferably used in the constitution of the pyrotechnic compositions because they ensure a cohesion between the grains of the composition and more particularly make it possible to avoid excessive stoichiometry deviations within these compositions. In the absence of control of the stoichiometric fluctuations of the pyrotechnic compositions, it is to be feared that the initiator's sensitivity characteristics (release thresholds) will be adversely affected.
  • the binders therefore have, among others, the function of contributing to the control of the reproducibility of stoichiometry within the compositions, especially since these can be manufactured and handled in bulk in relatively large quantities and therefore used under conditions that are sometimes likely to favor the migration and aggregation of some of the constituents between them.
  • the binders preferentially used generally have a relatively low softening temperature. Increases in temperature at such levels are very easy to achieve and control in a perfectly reproducible manner with the electrothermal bridges used for the electro-pyrotechnic initiation and this, without them being damaged. These electrothermal bridges have in fact been used for the most part for decades and their electrothermal behavior is fairly well known. For resistive type bridges, one can also simulate their behavior with the Rosenthal model as already indicated.
  • a liter for example it is possible to cause a heating of the composition around the electrothermal bridge between 150 ° and 250 °, the tripping threshold (firing being generally greater than 300 °), this corresponding to a current of a few hundred mA ( less than the tripping current threshold!) for an application time of several tens to a few hundred ms (between 100 and 200 ms for example).
  • a high intensity and a short application time are chosen rather than a low intensity and a prolonged application time in order to effectively obtain a temperature allowing the softening of the primary composition.
  • FIG. 1 is schematically shown in section an initiator 1, the section passing through the electrothermal bridge 2 symbolized by a resistor disposed within a primary composition 3 which has thermoplastic properties.
  • an initiator could have been manufactured by wet or dry technology. It should be noted that the thermoplastic properties could possibly have been used during manufacture
  • FIG. 2 shows the implementation of the method of the invention consisting in passing a current produced by an electrical source 4 in the electrothermal bridge 2 of an electric power of softening such as a softening of the composition primary 3 occurs in the environment of said bridge.
  • the softening electrical energy is left for a time sufficient for the primary composition rearranges in the environment and in contact with the electrothermal bridge.
  • FIG. 3 shows the final result of the implementation of the method of the invention on the initiator after returning to rest and base conditions. There is thus a reshaped zone 6 in relation to the electrothermal bridge and which substantially corresponds to the zone having previously undergone softening.
  • This determination of the temperature allows a secure implementation of the process by progressively increasing the energy sent into the electrothermal loop to a set temperature corresponding to the softening desired for the primary composition.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
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  • General Engineering & Computer Science (AREA)
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Abstract

The invention relates to a method of producing an electro-pyrotechnic interface between an electrothermal bridge (2) and a primary composition (3) inside an electro-pyrotechnic initiator (1), the latter being intended to produce a pyrotechnic effect when electrical energy above a trigger threshold is sent to the electrothermal bridge (2). The inventive method comprises the following steps consisting in: using a primary composition (3) having thermoplastic properties; assembling the electrothermal bridge (2) and the primary composition (3) with thermoplastic properties inside the initiator (1); and sending softening electrical energy (4) into the electrothermal bridge (2), which heats and softens (5) the primary composition (3) at least in the part that is in contact with the electrothermal bridge (2), said softening electrical energy being below the trigger threshold.

Description

Procédé de réalisation d'une interface électro¬ pyrotechnique entre un pont électrothermique et une composition primaire au sein d'un initiateur, initiateur obtenu. Process for producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition within an initiator, the initiator obtained
La présente invention concerne un procédé de réalisation d'une interface électro-pyrotechnique entre un pont électrothermique et une composition primaire au sein d'un initiateur électro-pyrotechnique ainsi que l'initiateur obtenu par le procédé. Elle a des applications dans le domaine de la pyrotechnique dans lequel on provoque la mise à feu de charges (explosives, fusantes, incendiaires ou autres) par l'intermédiaire d'un signal électrique.The present invention relates to a method for producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition within an electro-pyrotechnic initiator as well as the initiator obtained by the method. It has applications in the field of pyrotechnics in which it causes the firing of charges (explosive, fuzing, incendiary or other) through an electrical signal.
Les initiateurs électro-pyrotechniques sont des dispositifs dont la fonction est de transformer un signal d'entrée de type électrique en un effet pyrotechnique. Ces dispositifs permettent de générer des effets de flamme, de particules incandescentes, de gaz ou autres; ces effets pouvant éventuellement être combinés selon les cas. Les initiateurs permettent par exemple l'amorçage des explosifs d'abattage dans le domaine industriel des mines carrières et travaux publics, l'allumage de générateurs de gaz pour la sécurité automobile (systèmes de protection passive de type pré-tensionneurs de ceintures, enrouleurs pyrotechniques, coussins gonflables, etc. ), l'activation de pyromécanismes ou l'allumage de dispositifs de type missile ou fusée.Electro-pyrotechnic initiators are devices whose function is to transform an electrical type input signal into a pyrotechnic effect. These devices make it possible to generate effects of flame, incandescent particles, gases or others; these effects may possibly be combined according to the case. The initiators allow, for example, the priming of slaughter explosives in the industrial field of quarry and public works mines, the ignition of gas generators for automotive safety (passive protection systems of the pre-tensioning type of belts, pyrotechnic reels , airbags, etc.), the activation of pyromechanisms or the ignition of missile or rocket type devices.
Classiquement, les initiateurs électro-pyrotechniques comportent un pont électrothermique destiné à fournir de la chaleur (élévation de température) sous l'effet d'un courant électrique à une composition primaire qui, sous l'effet de la chaleur, est amenée à une réaction de décomposition combustive et/ou explosive. Le transfert de la chaleur entre le pont électrothermique et la composition primaire peut s'effectuer, selon les cas, par conduction ou convexion thermique. Le cas de la conduction thermique est bien connu et peut. être modélisé selon le modèle. djt de Rosenthal. On connaît ainsi des initiateurs dits «à fil chaud» qui sont des ponts électrothermiques de type filament métallique réalisés en général avec des alliages métalliques mais, parfois, avec un métal pur. D'autres initiateurs comportent des ponts électrothermiques à type de couches (films) ou feuillards pouvant être métalliques purs ou non (alliages), voire semi-conducteurs.Conventionally, the electropyrotechnic initiators comprise an electrothermal bridge for supplying heat (temperature rise) under the effect of an electric current to a primary composition which, under the effect of heat, is brought into a reaction. combustible and / or explosive decomposition. The transfer of heat between the electrothermal bridge and the primary composition can be effected, depending on the case, by conduction or thermal convection. The case of thermal conduction is well known and can. be modeled according to the model. djt from Rosenthal. So-called "hot wire" initiators are known which are electrothermal bridges of metal filament type generally made with metal alloys but sometimes with a pure metal. Other initiators include electrothermal bridges of the type of layers (films) or strips that can be pure or non-metallic (alloys), or even semiconductors.
On comprend que l'état de l'interface entre le pont électrothermique et la composition primaire peut influencer d'une manière importante les caractéristiques de l'initiateur, notamment en ce qui concerne les seuils de déclenchement (niveau d'énergie électrique entraînant la décomposition de la composition primaire), leur rapidité (vitesse de transfert de la chaleur du pont vers la composition), leur homogénéité (tous les initiateurs d'un lot ont sensiblement les mêmes caractéristiques).It is understood that the state of the interface between the electrothermal bridge and the primary composition can significantly influence the characteristics of the initiator, in particular with regard to the trip thresholds (electrical energy level causing the decomposition of the primary composition), their speed (speed of transfer of heat from the bridge to the composition), their homogeneity (all the initiators of a batch have substantially the same characteristics).
Traditionnellement, on peut distinguer deux grandes familles d'initiateurs en fonction du mode d'obtention de l'interface pyrotechnique entre le pont électrothermique et la composition primaire: les initiateurs de technologie dite «comprimée par voie sèche» et les initiateurs de technologie «trempée ou goutte par voie humide».Traditionally, two major families of initiators can be distinguished according to the manner of obtaining the pyrotechnic interface between the electrothermal bridge and the primary composition: the initiators of "dry compressed" technology and the initiators of "quenched" technology. or wet drop.
La technologie de type trempée ou goutte par voie humide présente certains avantages notamment en matière de sécurité de mise en oeuvre. Elle est maintenant bien connue et elle utilise généralement des compositions primaires à base de tri-nitro-résorcinate de plomb qui sont toutefois appelées à disparaître dans le futur du fait de la présence de plomb. Outre le fait que toutes les compositions primaires disponibles ne peuvent être mises sous une forme qui permette la mise en œuvre de la technologie par voie humide, cette dernière n'est pas propice à l'obtention de seuils de réaction pyrotechnique optimisés tant en terme de vitesse de réaction (temps de transfert de l'effet thermique du pont électrothermique vers la composition primaire) que de reproductibilité (niveaux des variations normales prévisibles).The type of hardened or wet-drop type technology has certain advantages, particularly in terms of safety of implementation. It is now well known and it generally uses primary compositions based on lead tri-nitro-resorcinate which are, however, expected to disappear in the future because of the presence of lead. In addition to the fact that not all available primary compositions can be put into a form that allows the implementation of wet technology, the latter is not conducive to obtaining pyrotechnic reaction thresholds optimized both in terms of reaction rate (transfer time of the thermal effect of the bridge electrothermal to the primary composition) than reproducibility (levels of predictable normal variations).
Le principal avantage de la technologie comprimé par voie sèche est qu'elle permet une optimisation (minimisation) de la vitesse de transfert thermique entre le pont électrothermique chauffé sous l'effet du signal électrique de mise à feu et la composition primaire. En effet, la compression de la composition primaire permet d'obtenir une meilleure « intimité » (contact) de celle-ci avec le pont. électrothermique. Toutefois, cette technique est plus contraignante du point de vue de la sécurité et elle ne peut pas utiliser une composition primaire qui a besoin de l'air pour que la décomposition se fasse de manière satisfaisante.The main advantage of the dry compressed technology is that it allows optimization (minimization) of the heat transfer rate between the electrothermal bridge heated under the effect of the electric firing signal and the primary composition. Indeed, the compression of the primary composition provides a better "intimacy" (contact) of it with the bridge. Electrothermal. However, this technique is more restrictive from the point of view of safety and it can not use a primary composition that needs air for the decomposition to be done satisfactorily.
La présente invention propose une méthode utilisable aussi bien avec une technique par voie humide ou voie sèche, quel que soit le type de pont électrothermique (fil, couche ou feuillard notamment) et qui permet d'améliorer le contact entre la composition primaire et le pont notamment afin d'améliorer les qualités de déclenchement/mise à feu (augmentation de la rapidité et amélioration de la reproductibilité) de l'initiateur. La méthode proposée peut être qualifiée de finition électrothermique d'interface pyroélectrique et elle consiste dans ses grandes lignes à mettre en œuvre une composition primaire présentant des qualités thermoplastiques (se ramollissant et devenant plastique ou fluide sous l'effet d'une augmentation de la température) et à entraîner un échauffement du pont thermique de l'initiateur, sans toutefois que le pont thermique ne soit dégradé, de manière à réaliser temporairement ce ramollissement/plasticité/fluidité (ces termes étant ici équivalents) de la composition primaire au moins dans l'environnement proche du pont thermique tout en ne provoquant pas la réaction de décomposition de ladite composition (absence de mise à feu). La durée du maintien de réchauffement du pont électrpthermique est adaptée à l'importance du ramollissement obtenu par ledit échauffement afin que la composition primaire se réarrange autour du pont électrothermique et permette un contact intime et définitif de la composition primaire avec le pont électrothermique. De préférence, réchauffement et/ou la composition est/sont tel/s que la composition devient fluide afin que la finition soit relativement courte dans le temps, une composition simplement ramollie ou plastifiée prenant plus de temps pour son réarrangement. On comprend qu'en dehors de cette finition, dans des conditions normales d'environnement, la composition est essentiellement solide.The present invention proposes a method that can be used both with a wet or a dry technique, whatever the type of electrothermal bridge (wire, layer or strip in particular) and which makes it possible to improve the contact between the primary composition and the bridge. in particular to improve the triggering / firing (speed increase and reproducibility enhancement) qualities of the initiator. The proposed method can be described electrothermal finish of pyroelectric interface and it consists in outline to implement a primary composition with thermoplastic qualities (softening and becoming plastic or fluid under the effect of an increase in temperature ) and to heat the thermal bridge of the initiator without, however, the thermal bridge is degraded, so as to temporarily achieve the softening / plasticity / fluidity (these terms being equivalent here) of the primary composition at least in the environment close to the thermal bridge while not causing the decomposition reaction of said composition (no ignition). The duration of the maintenance of heating of the electrothermic bridge is adapted to the importance of the softening obtained by said heating so that the primary composition is rearranged around the electrothermal bridge and allows an intimate and permanent contact of the primary composition with the electrothermal bridge. Preferably, the heating and / or the composition is such that the composition becomes fluid so that the finish is relatively short in time, a composition simply softened or plasticized taking more time for rearrangement. It is understood that outside this finish, under normal environmental conditions, the composition is essentially solid.
L'invention concerne donc un procédé de réalisation d'une interface électro-pyrotechnique entre un pont électrothermique et une composition primaire au sein d'un initiateur électro-pyrotechnique, l'initiateur étant destiné à produire un effet pyrotechnique lorsqu'une énergie électrique supérieure à un seuil d'énergie électrique de déclenchement est envoyée dans le pont électrothermique.The invention therefore relates to a method for producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition within an electro-pyrotechnic initiator, the initiator being intended to produce a pyrotechnic effect when a higher electrical energy at a threshold of electrical trip energy is sent into the electrothermal bridge.
Selon l'invention, on utilise une composition primaire qui présente des propriétés thermoplastiques, on assemble le pont électrothermique et la composition primaire à propriétés thermoplastiques au sein de l'initiateur et on envoie une énergie électrique de ramollissement dans le pont électrothermique qui provoque un chauffage et un ramollissement de la composition primaire au moins dans sa partie au contact du pont électrothermique, l'énergie électrique de ramollissement étant d'un niveau inférieur au seuil d'énergie électrique de déclenchement.According to the invention, a primary composition which has thermoplastic properties is used, the electrothermal bridge and the thermoplastic-containing primary composition are assembled in the initiator and electrical softening energy is sent into the electrothermal bridge which causes heating. and a softening of the primary composition at least in its part in contact with the electrothermal bridge, the electrical softening energy being of a level below the electric threshold of triggering energy.
Dans divers modes de mise en oeuvre de l'invention, les moyens suivants pouvant être utilisés seuls ou combinés selon toutes les possibilités techniquement envisageables, sont employés:In various embodiments of the invention, the following means can be used alone or combined according to all technically feasible possibilities, are used:
- l'assemblage du pont électrothermique et de la composition primaire est effectué par voie sèche en comprimant la composition à l'air ou sous atmosphère contrôlée,the assembly of the electrothermal bridge and of the primary composition is carried out by the dry route in compressing the composition in air or in a controlled atmosphere,
- l'assemblage du pont électrothermique et de la composition primaire est effectué par voie humide par trempage ou réalisation de goutte à l'air ou sous atmosphère contrôlée,the assembly of the electrothermal bridge and of the primary composition is carried out by wet process by dipping or producing a drop in the air or in a controlled atmosphere,
- le pont électrothermique est porté à une température telle que la composition primaire passe dans un état de ramollissement (= plasticité = fluidité) tout en étant à une température n'entraînant pas la dégradation dudit pont,the electrothermal bridge is brought to a temperature such that the primary composition passes into a state of softening (= plasticity = fluidity) while being at a temperature not causing degradation of said bridge,
- la composition primaire est dans un état de ramollissement (= plasticité = fluidité) pour une température approximativement supérieure ou égale à 150°,the primary composition is in a state of softening (= plasticity = fluidity) for a temperature approximately greater than or equal to 150 °,
- la composition primaire à une température de mise à feu approximativement supérieure à 300° et de préférence approximativement comprise entre 300° et 5000C,the primary composition at a firing temperature of approximately greater than 300 ° and preferably approximately between 300 ° and 500 ° C.,
- le pont électrothermique est porté à une température comprise entre 150° et 250°, ledit pont étant réalisé pour supporter une telle température sans dégradation, - les propriétés thermoplastiques de la composition primaire sont obtenues par la mise en œuvre d'un liant thermoplastique au sein de la composition,the electrothermal bridge is brought to a temperature of between 150 ° and 250 °, said bridge being made to support such a temperature without degradation; the thermoplastic properties of the primary composition are obtained by the use of a thermoplastic binder at within the composition,
- on utilise un liant à base d'élastomère,a binder based on elastomer is used,
- on utilise un liant à base de polybutadiène, - on utilise de préférence un liant fluoré,a binder based on polybutadiene is used, preferably a fluorinated binder is used,
- on utilise un liant à base d'élastomère fluoré,a binder based on fluoroelastomer is used,
- on utilise (par exemple) du VITON® pour le liant,- (for example) VITON® is used for the binder,
- en outre, lors de l'envoi de l'énergie électrique de ramollissement dans le pont électrothermique, on contrôle au moins un paramètre électrique dudit pont électrothermique qui est la résistance électrique,in addition, when sending the electrical softening energy into the electrothermal bridge, at least one electrical parameter of said electrothermal bridge is monitored which is the electrical resistance,
- lors de l'envoi de l'énergie électrique de ramollissement dans le pont électrothermique on estime la température dudit pont électrothermique par mesure de la résistance électrique dudit pont en fonction de l'énergie, au moins une première mesure préalable de résistance étant faite à un niveau d'énergie électrique réduit tel qu'il ne provoque pas d'élévation significative de Ia température dudit pont,when sending the electrical softening energy into the electrothermal bridge, the temperature of said electrothermal bridge is estimated by measuring the electrical resistance of said bridge as a function of the energy, at least a first a prior measurement of resistance being made at a reduced level of electrical energy such that it does not cause a significant rise in the temperature of said bridge,
- l'énergie électrique de ramollissement correspond à un courant continu,the electrical softening energy corresponds to a direct current,
- l'énergie électrique de ramollissement correspond à un courant alternatif,the electrical softening energy corresponds to an alternating current,
- l'énergie électrique de ramollissement correspond à un courant alternatif basse fréquence d'environ 50Hz ou 60Hz ou de leurs multiples jusqu'à trois fois,the electrical softening energy corresponds to a low frequency alternating current of approximately 50 Hz or 60 Hz or their multiples up to three times,
- l'énergie électrique de ramollissement correspond à un courant alternatif haute fréquence supérieure ou égale à 100KHz1 - the electrical softening energy corresponds to a high frequency alternating current greater than or equal to 100KHz 1
- l'énergie électrique de ramollissement correspond à une combinaison d'un courant continu et alternatif,the electrical softening energy corresponds to a combination of a direct and alternating current,
- le chauffage est progressif, (on augmente progressivement l'énergie dans le pont électrothermique)- the heating is progressive, (we gradually increase the energy in the electrothermal bridge)
- pendant le chauffage on vibre l'initiateur,during the heating, the initiator is vibrated,
- lorsque l'assemblage du pont électrothermique et de la composition primaire est effectué par voie sèche, on comprime la composition tout en envoyant l'énergie électrique de ramollissement dans le pont électrothermique pour provoquer le chauffage et le ramollissement.- When the assembly of the electrothermal bridge and the primary composition is carried out dry, the composition is compressed while sending the electric softening energy in the electrothermal bridge to cause heating and softening.
L'invention concerne également un dispositif à type d'initiateur électro-pyrotechnique comportant une interface électro-pyrotechnique entre un pont électrothermique et une composition primaire, l'initiateur étant destiné à produire un effet pyrotechnique lorsqu'une énergie électrique supérieure à un seuil d'énergie électrique de déclenchement est envoyée dans le pont électrothermique.The invention also relates to a device of the electro-pyrotechnic initiator type comprising an electro-pyrotechnic interface between an electrothermal bridge and a primary composition, the initiator being intended to produce a pyrotechnic effect when an electrical energy greater than a threshold of electrical trip energy is sent into the electrothermal bridge.
Selon le dispositif, la composition primaire présente des propriétés thermoplastiques et il est obtenu selon l'une ou plusieurs des caractéristiques précédentes.According to the device, the primary composition has thermoplastic properties and is obtained according to one or more of the preceding characteristics.
Le seuil d'énergie électrique de déclenchement peut être différent entre un même initiateur avant et après la mise en œuvre du procédé puisque le contact fonctionnel entre le pont électrothermique et la composition primaire de l'interface est amélioré. On comprend donc que l'énergie électrique de ramollissement qui est envoyée est d'un niveau inférieur au seuil d'énergie électrique de déclenchement le plus bas, c'est-à-dire celui qui est normalement obtenu après la mise en œuvre du procédé.The trigger electric energy threshold may be different between the same initiator before and after the implementation of the method since the functional contact between the electrothermal bridge and the primary composition of the interface is improved. It is therefore understood that the electrical softening energy that is sent is of a level below the threshold of the lowest electric trigger energy, that is to say that which is normally obtained after the implementation of the method .
De préférence, le procédé est mis en œuvre lors de la fabrication de l'initiateur et on livre des initiateurs qui ont déjà subi le procédé de l'invention. On envisage cependant que le procédé soit mis en œuvre sur le terrain avant l'utilisation (mise à feu). Dans ce dernier cas on envisage même de mettre la composition- primaire dans un état de ramollissement juste avant la mise à feu (que le procédé ait ou non précédemment déjà été mis en œuvre sur l'initiateur). On comprend que ces possibilités sur le terrain où généralement plusieurs initiateurs sont utilisés, nécessitent des conditions très particulières permettant d'agir précisément sur chacun des initiateurs, la mise en parallèle ou série sur une même ligne de commande de mise à feu rendant cette possibilité plus difficile.Preferably, the process is carried out during the manufacture of the initiator and initiators which have already undergone the process of the invention are delivered. It is envisaged, however, that the method is implemented in the field before use (firing). In the latter case it is even envisaged to put the primary composition in a state of softening just before firing (whether or not the process has already been implemented on the initiator). It is understood that these possibilities in the field where generally several initiators are used, require very specific conditions to act precisely on each of the initiators, the paralleling or series on the same command line firing making this possibility more difficult.
En outre, le procédé permet en une seule opération, en plus de l'amélioration de l'interface, un contrôle de la qualité du pont électrothermique car il est possible de mesurer les caractéristiques électriques, notamment la résistance électrique, du pont électrothermique pendant l'envoi de l'énergie de chauffage pour ramollissement de la composition primaire.In addition, the method allows in a single operation, in addition to improving the interface, a quality control of the electrothermal bridge because it is possible to measure the electrical characteristics, including the electrical resistance, of the electrothermal bridge during operation. sending the heating energy for softening the primary composition.
La présente invention va maintenant être exemplifiée par la description qui suit, sans en être pour autant limitée, et en relation avec : la Figure 1 qui représente en coupe schématique un initiateur venant d'être réalisé avant mise en œuvre du procédé de l'invention, la Figure 2 qui représente en coupe schématiq ue un initiateur dans lequel une énergie électrique de ramollissement est injectée, la Figure 3 qui représente en coupe schématique un initiateur obtenu après mise en œuvre du procédé de l'invention.The present invention will now be exemplified by the description which follows, without being limited thereby, and in relation to: FIG. 1 which represents in schematic section an initiator just made before implementing the method of the invention , Figure 2 which shows a schematic sectional view of an initiator in which electrical softening energy is injected, Figure 3 which shows in schematic section an initiator obtained after implementation of the method of the invention.
Dans le cas le plus classique de mise en œuvre de l'invention , la composition primaire comporte généralement des grains de matériaux sensibles à la chaleur (ceux qu i font une réaction ) qui sont liés entre-eux par au moins un liant. Les propriétés thermoplastiques de la composition primaire sont alors données par le liant qui présente de telles propriétés. L'invention , par un échauffement contrôlé et maîtrisé du pont et de la composition primaire voisine, permet d'obtenir la mise en contact intime et définitive (le ramollissement disparaît une fois que réchauffement est supprimé et que la composition baisse en température) des grains avec le pont électrothermique.In the most conventional case of implementation of the invention, the primary composition generally comprises grains of heat sensitive materials (those that make a reaction) which are bonded to each other by at least one binder. The thermoplastic properties of the primary composition are then given by the binder which has such properties. The invention, by a controlled and controlled heating of the bridge and the adjacent primary composition, makes it possible to obtain intimate and final contact (the softening disappears once the heating is removed and the composition decreases in temperature) of the grains. with the electrothermal bridge.
En d'autres termes, on applique à un Initiateur électro¬ pyrotechnique dont la composition primaire est à base de liant thermoplastique, un stimuii électrique calibré de sorte à obtenir localement au niveau de l'interface entre le pont électrothermique et la composition primaire, un échauffement suffisant, permettant d'assurer une mise en contact intime et définitive de la composition primaire avec le pont. Du fait de ce meilleur contact, les caractéristiques de mise à feu et leur reproductibilité sont améliorées, l'initiateur a moins de risque de voir ses caractéristiques évoluer suite à des chocs, manipulations, placement dans des environnements délétères (humidité notamment). Une telle méthode est possible dans le cas de compositions primaires contenant dans leur formulation une proportion de liant thermoplastique mais aussi dans le cas de compositions primaires intrinsèquement thermoplastiques. De nombreuses compositions pyrotechniques utilisées dans des applications de la pyrotechnie comportent des liants.. thermoplastiques. A titre d'exemple on peut notamment signaler les liants fluorés comme le VITON®. Dans le cas de compositions primaires ne contenant normalement pas de liant thermoplastique, il est généralement relativement aisé de modifier leur formulation de sorte à leur donner des propriétés thermoplastiques, notamment par utilisation d'un liant présentant de telles propriétés.In other words, an electro-pyrotechnic initiator whose primary composition is based on a thermoplastic binder is subjected to an electrical stimulus calibrated so as to obtain locally at the interface between the electrothermal bridge and the primary composition a sufficient heating, to ensure an intimate and permanent contact of the primary composition with the bridge. Because of this better contact, the firing characteristics and their reproducibility are improved, the initiator is less likely to see its characteristics evolve following shocks, manipulations, placement in deleterious environments (humidity in particular). Such a method is possible in the case of primary compositions containing in their formulation a proportion of thermoplastic binder but also in the case of intrinsically thermoplastic primary compositions. Many pyrotechnic compositions used in pyrotechnic applications include binders. thermoplastics. By way of example, mention may in particular be made of fluorinated binders such as VITON®. In the case of primary compositions normally containing no thermoplastic binder, it is generally relatively easy to modify their formulation so as to give them thermoplastic properties, especially by using a binder having such properties.
Les liants sont préférentiellement mis en œuvre dans la constitution des compositions pyrotechniques car ils assurent une cohésion entre les grains de la composition et permettent plus particulièrement d'éviter des écarts trop importants de stœchiométrie au sein de ces compositions. En l'absence de maîtrise des fluctuations de stœchiométrie des compositions pyrotechniques, on doit craindre des variations préjudiciables des caractéristiques de sensibilité (seuils de déclenchement) des initiateurs. Les liants ont donc, entre autres, pour fonction de contribuer à la maîtrise de la reproductibilité de la stœchiométrie au sein des compositions, d'autant plus que celles-ci peuvent être fabriquées et manipulées en vrac en quantités relativement importantes et donc mises en oeuvre dans des conditions parfois susceptibles de favoriser la migration et l'agrégation de certains des constituants entre eux.The binders are preferably used in the constitution of the pyrotechnic compositions because they ensure a cohesion between the grains of the composition and more particularly make it possible to avoid excessive stoichiometry deviations within these compositions. In the absence of control of the stoichiometric fluctuations of the pyrotechnic compositions, it is to be feared that the initiator's sensitivity characteristics (release thresholds) will be adversely affected. The binders therefore have, among others, the function of contributing to the control of the reproducibility of stoichiometry within the compositions, especially since these can be manufactured and handled in bulk in relatively large quantities and therefore used under conditions that are sometimes likely to favor the migration and aggregation of some of the constituents between them.
Les liants préférentiellement mis en œuvre ont généralement une température de ramollissement relativement basse. Des élévations de température à de tels niveaux sont très faciles à atteindre et maîtriser de façon parfaitement reproductibles avec les ponts électrothermiques utilisés pour l'initiation électro-pyrotechnique et, cela, sans qu'ils ne subissent de dégradations. Ces ponts électrothermiques sont en effet utilisés pour la plupart depuis des décennies et on connaît assez précisément leur comportement électrothermique. Pour les ponts de type résistifs, on peut également simuler leur comportement avec le modèle de Rosenthal comme on l'a .déjà indiqué. A litre d'exemple on peut provoquer un échauffement de la composition autour du pont électrothermique compris entre 150° et 250°, le seuil de déclenchement (mise à feu étant généralement supérieur à 300°), cela correspondant à un courant de quelques centaines de mA (inférieur au seuil de courant de déclenchement !) pour un temps d'application de plusieurs dizaines à quelques centaines de ms (entre 100 et 200 ms par exemple). De préférence on choisit une intensité élevée et un temps d'application court plutôt qu'une intensité faible et un temps d'application prolongé afin d'obtenir effectivement une température permettant le ramollissement de la composition primaire.The binders preferentially used generally have a relatively low softening temperature. Increases in temperature at such levels are very easy to achieve and control in a perfectly reproducible manner with the electrothermal bridges used for the electro-pyrotechnic initiation and this, without them being damaged. These electrothermal bridges have in fact been used for the most part for decades and their electrothermal behavior is fairly well known. For resistive type bridges, one can also simulate their behavior with the Rosenthal model as already indicated. A liter for example, it is possible to cause a heating of the composition around the electrothermal bridge between 150 ° and 250 °, the tripping threshold (firing being generally greater than 300 °), this corresponding to a current of a few hundred mA ( less than the tripping current threshold!) for an application time of several tens to a few hundred ms (between 100 and 200 ms for example). Preferably a high intensity and a short application time are chosen rather than a low intensity and a prolonged application time in order to effectively obtain a temperature allowing the softening of the primary composition.
Ainsi, on évite d'endommager le pont électrothermique ou la composition primaire lors du processus de stimulation électrothermique de l'interface qui n'a pas besoin, de se faire avec un échauffement trop important.Thus, it is avoided to damage the electrothermal bridge or the primary composition during the electrothermal stimulation process of the interface that does not need to be done with too much heating.
Afin d'encore mieux expliciter l'invention on va maintenant détailler les Figures.To further clarify the invention we will now detail the Figures.
Sur la Figure 1 on a représenté schématiquement en coupe un initiateur 1 , la coupe passant par le pont électrothermique 2 symbolisé par une résistance disposée au sein d'une composition primaire 3 qui présente des propriétés thermoplastiques. Un tel initiateur aura pu être fabriqué par une technologie par voie humide ou sèche. Notons que les propriétés thermoplastiques auront pu éventuellement être mises en oeuvre lors de la fabricationIn Figure 1 is schematically shown in section an initiator 1, the section passing through the electrothermal bridge 2 symbolized by a resistor disposed within a primary composition 3 which has thermoplastic properties. Such an initiator could have been manufactured by wet or dry technology. It should be noted that the thermoplastic properties could possibly have been used during manufacture
Sur la Figure 2 on a représenté la mise en œuvre du procédé de l'invention consistant à faire passer un courant produit par une source électrique 4 dans le pont électrothermique 2 d'une énergie électrique de ramollissement telle qu'un ramollissement 5 de la composition primaire 3 se produise dans l'environnement dudit pont. On laisse appliquée l'énergie électrique de ramollissement pendant un temps suffisant pour que la composition primaire se réarrange dans l'environnement et au contact du pont électrothermique.FIG. 2 shows the implementation of the method of the invention consisting in passing a current produced by an electrical source 4 in the electrothermal bridge 2 of an electric power of softening such as a softening of the composition primary 3 occurs in the environment of said bridge. The softening electrical energy is left for a time sufficient for the primary composition rearranges in the environment and in contact with the electrothermal bridge.
Su r la Figure 3 on a représenté le résultat final de la mise en œuvre du procédé de l'invention sur l'initiateur après retour à des cond itions de repos et de base. On note ainsi une zone remaniée 6 en relation avec le pont électrothermique et qui correspond sensiblement à la zone ayant précédemment subie le ramollissement.FIG. 3 shows the final result of the implementation of the method of the invention on the initiator after returning to rest and base conditions. There is thus a reshaped zone 6 in relation to the electrothermal bridge and which substantially corresponds to the zone having previously undergone softening.
Enfin, comme on l'a ind iqué pou r les ponts électrothermiques dont la valeur de résistance varie avec la température, il est possible de déterminer la température du pont électrotherm ique en connaissant la courbe de variationFinally, as indicated for electrothermal bridges whose resistance value varies with temperature, it is possible to determine the temperature of the electrothermal bridge by knowing the curve of variation.
"-- de résistance du pont en fonction de la température. Dans les cas où la formule suivante donnant la résistivité p en fonction de la température t s'applique et en connaissant les valeurs des paramètres, on peut également déduire la température par résolution de p=po(1 +at.) où a est le coefficient de température.- the resistance of the bridge as a function of temperature In the cases where the following formula giving the resistivity p as a function of the temperature t applies and knowing the values of the parameters, it is also possible to deduce the temperature by resolution of p = p o (1 + at.) where a is the temperature coefficient.
Cette détermination de la température permet une mise en œuvre sécurisée du procédé en augmentant progressivement l'énergie envoyée dans la boucle électrothermique jusqu'à une température de consigne correspondant au ramollissement souhaité pour la composition primaire. Les exemples qui ont été donnés sont indicatifs et on comprend que l'homme du métier peut réaliser l'invention selon de nombreuses autres variations sans sortir de la portée de la présente invention . This determination of the temperature allows a secure implementation of the process by progressively increasing the energy sent into the electrothermal loop to a set temperature corresponding to the softening desired for the primary composition. The examples which have been given are indicative and it is understood that one skilled in the art can realize the invention according to many other variations without departing from the scope of the present invention.

Claims

REVENDICATIONS
1. Procédé de réalisation d'une interface électro¬ pyrotechnique entre un pont électrothermique (2) et une composition primaire (3) au sein d'un initiateur (1 ) électro¬ pyrotechnique, l'initiateur étant destiné à produire un effet pyrotechnique lorsqu'une énergie électrique supérieure à un seuil d'énergie électrique de déclenchement est envoyée dans le pont électrothermique, dans lequel on utilise une composition primaire qui présente des propriétés thermoplastiques, on assemble le pont électrothermique et la composition primaire à propriétés thermoplastiques au sein de l'initiateur et on chauffe la composition primaire pour provoquer un ramollissement, caractérisé en ce que l'on envoie une énergie électrique de ramollissement (4) dans le pont électrothermique qui provoque un chauffage et un ramollissement (5) de la composition primaire au moins dans sa partie au contact du pont électrothermique, l'énergie électrique de ramollissement étant d'un niveau inférieur au seuil d'énergie électrique de déclenchement.1. A method for producing an electro-pyrotechnic interface between an electrothermal bridge (2) and a primary composition (3) within an electro-pyrotechnic initiator (1), the initiator being intended to produce a pyrotechnic effect when an electrical energy greater than a threshold of electrical trip energy is sent into the electrothermal bridge, in which a primary composition which has thermoplastic properties is used, the electrothermal bridge and the thermoplastic-containing primary composition are assembled within the electrothermal bridge; initiator and the primary composition is heated to cause softening, characterized in that electrical softening energy (4) is supplied to the electrothermal bridge which causes heating and softening (5) of the primary composition at least in its part in contact with the electrothermal bridge, the electrical energy of softening being of a level water below the electric threshold of tripping energy.
2. Procédé selon la revendication 1 , caractérisé en ce que l'assemblage du pont électrothermique et de la composition primaire est effectué par voie sèche en comprimant la composition à l'air ou sous atmosphère contrôlée.2. Method according to claim 1, characterized in that the assembly of the electrothermal bridge and the primary composition is carried out by dry process by compressing the composition in air or in a controlled atmosphere.
3. Procédé selon la revendication 1 , caractérisé en ce que l'assemblage du pont électrothermique et de la composition primaire est effectué par voie humide par trempage ou réalisation de goutte à l'air ou sous atmosphère contrôlée.3. A method according to claim 1, characterized in that the assembly of the electrothermal bridge and the primary composition is carried out wet by dipping or producing drop in air or in a controlled atmosphere.
4. Procédé selon la revendication 1 , 2 ou 3, caractérisé en ce que le pont électrothermique est porté à une température comprise entre 15O0C et 2500C, ledit pont étant réalisé pour supporter une telle température sans dégradation et la composition primaire étant _dans _ un état —de ramollissement pour une température approximativement supérieure ou égale à 150°.4. Method according to claim 1, 2 or 3, characterized in that the electrothermal bridge is brought to a temperature between 15O 0 C and 250 0 C, said bridge being made to support such a temperature without degradation and the primary composition being _in _ a state -de softening for a temperature of approximately 150 ° or more.
5. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que les propriétés thermoplastiques de la composition primaire sont obtenues par la mise en œuvre d'un liant thermoplastique au sein de la composition.5. Method according to any one of the preceding claims, characterized in that the thermoplastic properties of the primary composition are obtained by the implementation of a thermoplastic binder within the composition.
6. Procédé selon la revendication 5, caractérisé en ce que le liant est à base d'élastomère fluoré ou non, notamment un liant à base de polybutadiène.6. Method according to claim 5, characterized in that the binder is based on fluoroelastomer or not, especially a binder based on polybutadiene.
7. Procédé selon la revendication 6, caractérisé en ce que l'on utilise du VITON® pour le liant.7. Process according to claim 6, characterized in that VITON® is used for the binder.
8. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce qu'en outre, lors de l'envoi de l'énergie électrique de ramollissement dans le pont électrothermique, on contrôle au moins un paramètre électrique dudit pont électrothermique qui est la résistance électrique.8. Method according to any one of the preceding claims, characterized in that in addition, when sending the electrical softening energy in the electrothermal bridge, at least one electrical parameter of said electrothermal bridge is controlled which is the electrical resistance.
9. Procédé selon l'une quelconque des revendications précédentes, caractérisé en ce que lors de l'envoi de l'énergie électrique de ramollissement dans le pont électrothermique on estime la température dudit pont électrothermique par mesure de la résistance électrique dudit pont en fonction de l'énergie, au moins une première mesure préalable de résistance étant faite à un niveau d'énergie électrique réduit tel qu'il ne provoque pas d'élévation significative de la température dudit pont.9. Method according to any one of the preceding claims, characterized in that during the sending of the electrical softening energy in the electrothermal bridge is estimated the temperature of said electrothermal bridge by measuring the electrical resistance of said bridge as a function of the energy, at least a first prior resistance measurement being made at a reduced electrical energy level such that it does not cause significant rise in the temperature of said bridge.
10. Dispositif à type d'initiateur (1 ) électro¬ pyrotechnique comportant une interface électro-pyrotechnique entre un pont électrothermique (2) et une composition primaire (3), l'initiateur étant destiné à produire un effet pyrotechnique lorsqu'une énergie électrique supérieure à un seuil d'énergie électrique de déclenchement est envoyée dans le pont électrothermique, caractérisé en ce que la composition primaire présente des propriétés thermoplastiques et que l'initiateur est réalisé selon l'une quelconque des revendications précédentes. 10. An electro-pyrotechnic initiator device (1) having an electro-pyrotechnic interface between an electrothermal bridge (2) and a primary composition (3), the initiator being intended to produce a pyrotechnic effect when an electrical energy greater than a threshold of electrical trip energy is sent into the electrothermal bridge, characterized in that the primary composition has thermoplastic properties and the initiator is made according to any one of the preceding claims.
PCT/FR2005/002759 2004-11-05 2005-11-04 Method of producing an electro-pyrotechnic interface between an electrothermal bridge and a primary composition inside an initiator, and initiator thus obtained WO2006051199A1 (en)

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EP1809980A1 (en) 2007-07-25
ATE396376T1 (en) 2008-06-15
FR2877720A1 (en) 2006-05-12
DE602005007054D1 (en) 2008-07-03
EP1809980B1 (en) 2008-05-21
FR2877720B1 (en) 2009-11-06

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