Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C13/00—Portable extinguishers which are permanently pressurised or pressurised immediately before use
  • A62C13/02—Portable extinguishers which are permanently pressurised or pressurised immediately before use with pressure gas produced by chemicals
  • A62C13/22—Portable extinguishers which are permanently pressurised or pressurised immediately before use with pressure gas produced by chemicals with incendiary substances producing pressure gas
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C35/00—Permanently-installed equipment
  • A62C35/02—Permanently-installed equipment with containers for delivering the extinguishing substance
  • A62C35/023—Permanently-installed equipment with containers for delivering the extinguishing substance the extinguishing material being expelled by compressed gas, taken from storage tanks, or by generating a pressure gas
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62C—FIRE-FIGHTING
  • A62C35/00—Permanently-installed equipment
  • A62C35/02—Permanently-installed equipment with containers for delivering the extinguishing substance
  • A62C35/08—Containers destroyed or opened by bursting charge

Definitions

• the present invention relates to a method for delivering a liquid contained in a reservoir, said liquid being pressurized by the combustion gases of at least one pyrotechnic charge. a pyrotechnic charge. It also relates to pyrotechnic charges adapted to the implementation of this method. This method is expediently implemented for the delivery of a liquid fire extinguishing agent.
• the method of the invention (and its prior art) is (are) more particularly described in this context. This is however in no way limiting.
• Fire extinguishing devices generally include a tank containing an extinguishing agent (liquid agent).
• the said agent is intended to be broadcast on the zone of a fire, with a view to extinguishing the said fire but also to preventing its extension.
• Conventional tank fire extinguishers are permanently pressurized (essentially consist of a) a gas pressure tank containing the extinguishing agent or b) a pressurized gas cylinder connected to the extinguishing agent container ( reservoir), said cylinder, once struck, releasing the pressurizing gas from the extinguishing agent).
• the use of these extinguishers therefore comprises the permanent storage under pressure, an extinguishing agent (variant a) or a propellant of such an extinguishing agent (variant b), with the necessary monitoring operations. and verification (as the periodic weighing) that implies.
• the pressure of the gas (variants a and b) also varies with the temperature, the range of use of the fire extinguisher is therefore limited.
• devices comprising a pyrotechnic gas generator, the pyrotechnic gases generated by said generator suitable for pressurizing and delivering the liquid extinguishing agent.
• a pyrotechnic gas generator is efficient, effective and particularly advantageous in that their use does not imply the storage and management of gas under pressure.
• the patent application EP 1 782 861 describes a fire extinguishing device comprising an extinguishing agent tank (liquid) and means for generating a gas under pressure, said means possibly consisting of a pyrotechnic gas generator.
• a separating element for example a flexible membrane, is provided for separating said gas generator from said extinguishing agent.
• the membrane deploys under the effect of the pressure of the generated gases and expels the extinguishing agent from the reservoir via a tared operculum after rupture of said tared operculum under the effect of the pressure of said agent. extinction.
• Patent Application EP 2 205 325 describes a device comprising a cylindrical body housing a sliding piston, defining on one side, a chamber forming a reservoir, filled with extinguishing agent (liquid, at its saturation vapor pressure). , under a gaseous sky) and on the other side, a chamber containing a pyrotechnic gas generator. When the gas generator is actuated, the gas pressure moves the piston so that the extinguishing agent is expelled from the tank.
• extinguishing agent liquid, at its saturation vapor pressure
• the patent application WO 2008/025930 describes a pyrotechnic gas generator adapted to operate extinguishers of the type of those raised.
• the pyrotechnic charge of the generator advantageously consists of at least one monolithic block, solid or with a central channel, of large dimensions (uninhibited, ie without inhibitor of combustion on its surface): a cylindrical monolithic block whose two dimensions, thickness and diameter, are between 10 and 75 mm.
• the composition of this pyrotechnic charge is advantageously based on basic copper nitrate (BCN) and guanidine nitrate (NG).
• Propellant blocks used must be of sufficient size to give the gas generator an operating time compatible with the desired extinguishing function. This operating time is greater than that required in the field of motor vehicle safety, more particularly for the operation of airbags and pyrotechnic actuators such as seat belt pretensioners and bonnet lifter actuators.
• the duration of delivery of the pressurized liquid is typically, for a fire extinguisher, from a few seconds to several tens of seconds.
• the present invention therefore relates to a method for delivering a liquid, in particular a liquid extinguishing agent, contained in a reservoir, said reservoir having at least one delivery orifice of said liquid closed by an erasable lid under a threshold pressure applied to said liquid (if several delivery ports exist, they are each closed by an erasable operculum under a threshold pressure of the same intensity).
• Said erasable seal is advantageously able to disappear without causing any gene to the course of the process (i.e the operation of the device in which said method is implemented), without in particular generating fragments or debris. It is thus advantageously of the frangible membrane type shaped petals or spring valve.
• said method comprises:
• the process thus comprises a transitional phase during which the combustion gases of the pyrotechnic charge ensure the pressurization of the liquid until the gate is cleared of the at least one delivery orifice, followed by an "active phase ": That of the delivery of the liquid.
• the aim is to shorten the duration of this transitional phase (which is a delay time between the detection of the event and the response to said event).
• the flow of combustion gas generated during the delivery of the liquid ensures an almost constant pressurization of said liquid and therefore the delivery of said liquid (pressurized) to almost constant flow.
• the concept of almost constant pressurization is quantified below: the pressure of said liquid, during the delivery of said liquid, varies at most by +/- 30%, advantageously not more than +/- 20%, very advantageously than at most of +/- 10%, relative to its initial value at the time of erasure of (said) operculum (s).
• the delivery of the liquid is advantageously carried out, in dispersed form, via a (spray) nozzle.
• the sensitivity of the delivery rate to the pressure variations of said liquid is attenuated (said delivery flow by a nozzle responding, as a rule, to a law in P n , with P the pressure of said liquid and n ⁇ 1 ).
• the delivery rate of the liquid by a nozzle in the ranges of variation The pressure of the liquid evoked, is thus likely to vary at most by +/- 15%, preferably at most than +/- 10%, very advantageously at most than +/- 5%.
• the delivery of the liquid (pressurized) is thus implemented at almost constant rate by a quasi constant pressurization of said liquid.
• the process of the invention is original.
• the delivery of the pressurized liquid with a quasi constant flow rate implies a (decreasing) variation of the volume occupied by the quasi-constant liquid (of the volume of the reservoir) and corresponds to a (increasing) variation of the volume occupied by the quasi-pressurizing gases. constant.
• the method of the invention is implemented in a device comprising said liquid reservoir and at least one pyrotechnic gas generator enclosing said at least one pyrotechnic charge (the combustion of which generates the combustion gases necessary for pressurization of the liquid); said at least one pyrotechnic gas generator being connected to said tank and a movable member for separating the generated combustion gases and said liquid being provided within said device.
• said movable member contributes to the constancy of the pressurization of the desired liquid (see above), by "balancing" the pressures applied to its surface.
• Said movable member is also interesting because of the separation function (combustion gas / liquid) that it exerts. It may be particularly appropriate to protect the liquid from gases. In any case, the formation of a foam, detrimental to effective delivery of liquid, should be avoided.
• the device of the invention comprises at least one nozzle (nozzle with adjustable neck surface or constant neck surface), through which the generated combustion gases are discharged (evacuated from said at least one pyrotechnic generator).
• said device does not contain such a nozzle.
• the desired result (as to the almost constant pressurization of the liquid) can be achieved without the use of any nozzle (see below).
• the device of the invention can be of very simple design.
• the almost constant pressurization avoids the oversizing of the structural elements of the tanks of the prior art (oversizing intended to withstand a high level of pressure at the beginning of delivery of the liquid, imposed by the decrease in pressure over time) and therefore allows operate in lighter structures (in which the problem of gas / liquid mixtures does not arise).
• the almost constant delivery rate ensures almost constant efficiency of the delivered liquid throughout the delivery.
• the number of moles N of pressurizing gas by the temperature T of said gases, divided by the volume V of the pressurized reservoir is almost constant (therefore only varies by a maximum of +/- 30%, preferably by a maximum of +/- 20%, very advantageously with a maximum of +/- 10%).
• the temperature of the pressurizing gases does not vary significantly during liquid delivery. However, it is possible, for example because of thermal losses of a device with little heat insulation and thus taking time to heat up, that the temperature T of said gases varies slightly in increasing (AT ⁇ 100 ° C) during the delivery of the liquid.
• Vc is the burning rate of the propellant in mm / s
• n the exponent of pressure of the law of speed of combustion
• a slightly decreasing gas flow rate can therefore be obtained by combustion of a pyrotechnic charge ("of any geometry") in a combustion chamber equipped with a nozzle with adjustable neck section (see above), but the inventors recommend strongly (see above) to obtain such a slightly decreasing gas flow by much simpler means, particularly suitable for contexts extinguishers.
• the applicant proposes, in the context of the invention, the use of specific pyrotechnic charges, suitable for inducing a flow of combustion gas slightly decreasing, the use of pyrotechnic charges having a portion of their combustion surface inhibited in combustion.
• Such types of pyrotechnic charges are, to date, used in contexts different from that of the invention, especially in propulsion.
• the present invention actually provides an original outlet, an original use for this type of pyrotechnic loadings.
• the pyrotechnic charges which have the shape of a straight cylinder with a circular section with a lateral surface developing over their entire length between two end faces, of the solid monolithic block type or of the "near perfect" disk stack type (the disks). stacked constituting an almost monolithic structure); only one of their end face being inhibited in combustion.
• Such charges are suitable insofar as they are likely to burn only on their lateral face and on one of their end face;
• pyrotechnic charges which have a frustoconical shape, with a lateral surface developing over their entire length between two end faces, of solid monolithic block type or of "quasi-perfect" disk stack type (constituting an almost monolithic structure); their lateral surface and the end face of smaller section being inhibited in combustion while the other end face of greater section is not inhibited in combustion.
• Such charges are suitable insofar as they are only likely to burn in frontal combustion or combustion in "conical cigarette";
• the pyrotechnic charges which have a tubular shape having a lateral surface developing over their entire length between two end faces and a cylindrical or star-shaped central channel, of the solid monolithic block type or of the almost perfect disk stack type "(Constituting an almost monolithic structure); their end faces being inhibited (their lateral surface not being inhibited).
• Such charges are suitable insofar as they burn in their channel (inner surface) and on their lateral surface.
• the person skilled in the art is able to optimize, according to the exact characteristics of the device in question, in particular its thermal insulation, the pyrotechnic charges having part of their combustion surface inhibited in combustion, at a slightly decreasing flow rate, ensuring a quasi-pressurization constant of the liquid during the delivery phase.
• the loadings described above have been referred to the active phase. It is easy to conceive that they can present, before any use, a uniform geometry, for a larger volume, so that they burn uniformly, successively, both during the transient phase and during the active phase. It is also possible to provide a binary structure, in particular that an additional load is secured to said loadings described above; said additional loading being intended to burn during the transient phase, advantageously intended to burn so as to shorten said transient phase.
• a quasi constant gas flow can be obtained by combustion of a pyrotechnic charge ("of any geometry") in a combustion chamber equipped with a nozzle with adjustable neck section (see above), but the inventors here, too, strongly recommend that such a quasi-constant gas flow be obtained by much simpler means, particularly suited to extinguisher contexts.
• a quasi-constant gas flow can thus be advantageously obtained, without using a nozzle with a modular neck section (see above), with a pyrotechnic charge that burns, at an almost constant combustion pressure (varying only at maximum of +/- 30%, advantageously not more than +/- 20%, very advantageously not more than +/- 10%), presenting (during its combustion, therefore) an almost constant combustion surface .
• Vc a P n , with n generally between 0 and 0.6
• an almost constant combustion surface corresponds, in the sense of the invention, to a combustion surface varying at most by only +/- 15%, advantageously not more than +/- 10%, very advantageously not more than +/- 5%.
• the almost constant combustion pressure of an almost constant combustion surface pyrotechnic charge can be ensured either by including the pyrotechnic charge in an almost constant pressure volume (it is thus, in the context of the invention, the pressurization volume (to the extent that the (increasing) variation in the volume occupied by the pressurizing gases corresponds to the (decreasing) variation of the volume occupied by the pressurized liquid, during the delivery of said pressurized liquid), or by including the loading pyrotechnic in a combustion chamber provided with a nozzle with a constant neck surface (the intervention of such a nozzle (less sophisticated than that of a nozzle with adjustable neck section (see above)) is advantageous in that that it allows an easy adjustment of the pressure.)
• the pressure exponent of a propellant constituting a pyrotechnic charge must be less than 1 to ensure a constant combustion rate at constant pressure, preferably less than 0.8, very advantageously less than 0.6.
• a quasi-constant combustion surface suitable for inducing a quasi-constant combustion gas flow rate with almost constant combustion pressure, can itself be obtained with pyrotechnic charges having a part of their combustion surface which is inhibited during combustion.
• the pyrotechnic charges suitable for generating, by combustion, an almost constant gas flow at almost constant pressure with an almost constant combustion surface, by the combustion inhibition of a part of their combustion surface
• the pyrotechnic charges (of a first type that may be described as type A, shown diagrammatically in FIGS. 1 and appended) which have the shape of a straight cylinder with a circular section with a lateral surface developing over their entire length between two end faces, of the solid monolithic block type or stacked disk type; their lateral surface and one of their end faces being inhibited in combustion while the other end face is not inhibited in combustion.
• Such charges are suitable insofar as they are only likely to burn in frontal combustion or "cigarette"combustion;
• pyrotechnic charges of a second type that may be described as type B, which have a tubular shape, having a lateral surface developing over their entire length between two end faces and a cylindrical central channel , of the solid monolithic block type or of the "almost perfect" disk stack type (the stacked disks constituting an almost monolithic structure); only one of their end faces being inhibited in combustion.
• Such charges are suitable insofar as they burn on their lateral surface (outer surface), in their channel (inner surface) and on their uninhibited end face;
• pyrotechnic charges (of a third type that may be described as type C), which have a tubular form (of external diameter D1), having a lateral surface developing over their entire length between two end faces as well as a cylindrical central channel (of diameter D2), of solid monolithic block type or "almost perfect" disk stack type (the stacked disks constituting an almost monolithic structure); (only) their lateral surface being inhibited in combustion and their length being equal to or approximately equal to 1.5 times their outer diameter (D1) plus 0.5 times the diameter of their central channel (D2);
• pyrotechnic charges of a fourth type that may be described as type D
• type D pyrotechnic charges
• Such loads are suitable insofar as they burn in their channel (inner surface) and on their end faces.
• the pyrotechnic charges of the first type above are widely preferred because their architecture is simple and their combustion surface and therefore their flow rate of gas (combustion generated) at constant pressure approach an almost perfect constant.
• their combustion mode front combustion or "cigarette” combustion
• Type A pyrotechnic charges are therefore particularly suitable for generating a quasi-constant gas flow during the liquid delivery phase, or even during the pressurization and liquid delivery phase (see below).
• the pyrotechnic charges mentioned above in particular those of the types specified above, have been described with reference to the implementation of the "active phase" of the process of the invention: that of the delivery of the liquid. It should therefore be understood that, during the delivery of the liquid, the pyrotechnic charge in combustion is advantageously of the type A, B, C or D above, very advantageously of the type A above.
• the at least one pyrotechnic charge having a straight cylinder shape with a circular section with a lateral surface developing over its entire length between two end faces, solid monolithic block type or stack type of disks, is in front combustion only; its lateral surface and its opposite end face to the end face in combustion being inhibited in combustion.
• the at least one pyrotechnic charge (intended to be burned) has in fact an overall structure which comprises a portion (a portion) intended to be burned during the transitional phase (preliminary to the delivery phase) and another part (another portion) intended to be burned during the "active phase” (phase of delivery of the pressurized liquid).
• the at least one pyrotechnic charge has in fact an overall structure which comprises a portion (a portion) intended to be burned during the transitional phase (preliminary to the delivery phase) and another part (another portion) intended to be burned during the "active phase” (phase of delivery of the pressurized liquid).
• it can have a uniform overall structure, for a "uniform" combustion during the transient phase and during the "active phase” or have a non-uniform, "more complex", at least binary, overall structure. for a priori a different combustion during the transient phase and during the "active phase”.
• the flow rate of combustion gas generated by the at least one pyrotechnic charge is increasing or increasing then almost constant or almost constant (Q1), during the pressurization phase of the liquid (transient phase concluding by the erasure of the operculum (operculum)) (and almost constant during the delivery of the liquid); and according to a second alternative embodiment of the method of the invention, the flow of combustion gas generated by the pyrotechnic charge during the pressurization phase of the liquid is managed, controlled, in order to shorten said pressurization phase of the liquid (transient phase concluding by the erasure of the lid (operculum)): it is actually increased compared to the flow Ql above.
• Said loading has two combustion regimes, the first providing a "high" flow (increased with respect to Ql) during the pressurization phase and the second an almost constant flow rate during the delivery phase.
• the transient phase and the active phase it is possible in particular to operate, during the two phases (the transient phase and the "active phase"), according to the same mode of combustion, with at least one pyrotechnic charge of uniform structure, advantageously the same mode of combustion in "cigarette” with at least one type A pyrotechnic charge (see above).
• the at least one pyrotechnic charge has a structure that is at least binary with a portion (a section) that generates combustion gases at an increased rate (second variant) or decreased (third variant) and another part (another section) generating combustion gases at a nearly constant rate during the delivery of the liquid, hence the above concept of non-uniform global structure.
• the first section may exist in many variants, as to its shape (cylindrical, frustoconical, cubic shape, for example), and as to its constitution (solid monolithic block, stack of structures such as disks, cylinders or cubes, for example).
• At least one pyrotechnic charge having a straight cylinder shape with a circular cross-section with a lateral surface developing throughout its length between two end faces, of monolithic block type full or stack type of disks; its combustion inhibited lateral surface over a portion of the length of the cylinder from one of its end faces, itself inhibited in combustion, not being inhibited in combustion on the complementary part of the length of the cylinder from the other of its non-inhibited end faces in combustion.
• the type A pyrotechnic charge may thus consist of a first section, on the side of the uninhibited end face in combustion, of a propellant with a high combustion speed Vci (P) and a second juxtaposed section of another propellant with a lower combustion rate Vc 2 (P) .
• the operating mode of such a pyrotechnic charge is therefore the following: during the pressurization of the liquid, one (first) part, not inhibited in combustion or of which a part of the combustion surface is inhibited during combustion, the pyrotechnic charge burns at a high combustion rate to ensure pressurization over a short time of said liquid until the said seal is erased , then, during the delivery of said liquid, the complementary part of said pyrotechnic charge, having a straight cylinder shape with a circular section with a lateral surface developing r its entire length between two end faces, solid monolithic block type or disk stack type, said lateral surface and said end face opposite to the burning end
• Such a multi-component, at least two-component, pyrotechnic charge therefore generates, with a constant or non-constant combustion surface, during the pressurization phase of the liquid, a first gas flow ensuring a pressurization over a short time of said liquid (resulting of the combustion of the first section consisting of at least one propellant with a high combustion rate), making it possible to reach in a short time the erasure pressure of (s) operculas (s), then, during the delivery phase of the liquid, a second flow of gas over a long time, constant, at constant pressure, (resulting from the "cigarette" combustion of the second section consisting of a propellant with a lower combustion rate) ensuring the constant pressurization of said liquid during a long time.
• the first part of the at least one A-type bicomponent loading may be at least partially inhibited (type A-1, shown schematically in the appended Figure 3) or non-inhibited (type A). 2, schematized in the appended FIGURE 4. It will be understood that the non-inhibition of the high-velocity portion of combustion is even more favorable to the shortening of the duration of the transient phase. corresponds to a charge of type A ', constituted for the uninhibited part of its lateral surface of a combustion rate propellant Vci (P) and for the complementary part of its side surface, which is inhibited by a propellant with a combustion rate Vc 2 (P): Vci (P)> Vc 2 (P).
• the first section may in fact exist in many variants, in particular with regard to its shape and constitution (see above), its number of components (n ⁇ l) and the identical or different composition of said components ( n ⁇ 2) (their burn rate Vci (P) identical or not, the said speed (s) VCi (P) being, in any case, greater (s) than that of the second section) .
• Said first section advantageously exists according to the same geometry as that of the second section (cylinder with circular section), and, whether or not a single component, with a combustion speed (s) Vci (P) greater than that of the second section. .
• pyrotechnic charges at least two components of another type (VCi (P) ⁇ Vc 2 (P): see above) can be used for the implementation of the third variant of the method of the invention. invention, less recommended.
• the combustion of the at least one pyrotechnic charge can be carried out with a control of the combustion pressure.
• said combustion can be implemented in a combustion chamber provided with a nozzle (see above).
• This variant is advantageous insofar as the combustion pressure of the charge, and therefore its combustion rate, are independent of the pressurization pressure of the liquid, which facilitates the adjustment of operation during the implementation of the method.
• the pressurized liquid is advantageously delivered in dispersed form, via a nozzle.
• the constant flow delivery of the liquid then allows, via said nozzle, a dispersion of constant quality throughout the delivery phase (see above).
• the liquid in question may especially consist of an extinguishing agent (of fires) (water, water + additives, ....), a lubricating agent, a cooling agent (water, glycol, etc.), a cleaning agent and / or dispersant (surfactant liquid .).
• the delivery of the liquid at a constant rate ensures a very interesting supply of a constant quantity of liquid on the recipient, which requires said liquid supply (ie the fire to extinguish and to circumscribe, in a context of delivery of an extinguishing agent, ie the machine which heats up, in a context of delivery of a lubricating agent, ie the pollution to be combated, in a delivery context a cleaning and / or dispersing agent ).
• such devices comprise, in their structure, a reservoir (for the liquid to be delivered) and at least one pyrotechnic gas generator containing at least one pyrotechnic charge; said at least one pyrotechnic gas generator being connected to said tank and a movable member for separating the generated combustion gases and said liquid being provided within said device.
• Such devices include, in their basic structure, a tank connected to a gas generator containing a pyrotechnic charge. It is understood that their structure can in fact be more complex, with several generators arranged in parallel upstream of the tank; each of said generators enclosing one or more loads. In any case, one or more generators are likely to debit in one or more tanks. The device is therefore likely to include several tanks. In any state of cause, the method of the invention is implemented at each of said tanks.
• the device in question is advantageously a compact device (therefore of limited size).
• a compact device comprises a one-piece body (in one piece, unitary) in which are arranged the reservoir and the at least one pyrotechnic generator.
• the at least one pyrotechnic generator is arranged in (the volume of) the reservoir.
• the movable separating member may consist of a flexible membrane or a piston. It consists advantageously of a piston.
• a device not including a nozzle, is perfectly suitable for implementing the method of the invention (see above).
• the method of the invention can therefore also be implemented in a device according to the second variant above, which device advantageously comprises at least one pyrotechnic generator (generally a single such pyrotechnic generator) arranged in the upper part of the internal volume (empty ) a reservoir containing the liquid to be delivered.
• a flexible membrane shares the internal volume of the reservoir (the combustion gases then act on this membrane to act on the liquid) or is associated with the at least one gas generator (the combustion gases inflate such a membrane to act on the liquid) .
• Such a device comprising or not including a nozzle (s), advantageously not including a nozzle, is ideal for implementing the method of the invention (see above).
• the method of the invention is thus advantageously implemented in devices whose exact structure has been recalled above.
• the devices in question furthermore comprise means for initiating combustion, i.e. an ignition system of the at least one pyrotechnic charge, which generates the gases.
• an ignition system generally comprises an initiator and an igniter.
• the initiator may consist of:
• a hot spot on the surface of the igniter such as a hot wire, or a piezoelectric element
• igniter can consist of:
• a pyrotechnic igniter type "microroquette” comprising a fast-burning pyrotechnic charge (type composition dual base propellant or Butalite ® ) (mass ⁇ a few grams), disposed in a combustion chamber with nozzle whose jet is directed to the surface loading, and / or
• an igniter consisting of one or more reactive ignition pellets (whose composition is of the B / KNO 3 or TiH 2 / KCLO 4 or NH 4 CLO 4 / NaNO 3 / binder type) disposed on the surface free from pyrotechnic loading, and / or
• an igniter consisting of one or more pellets (the composition of which is of basic copper nitrate (BCN) / guanidine nitrate (NG) type).
• the pyrotechnic igniter also contributes to the generation of gas. It can be sized to contribute significantly to the supply of gas during said transient phase, especially when it is desired to shorten said transient phase.
• composition of the pyrotechnic charges useful for carrying out the process of the invention the following indications may be given in a non-limiting manner.
• This composition is advantageously of the type of pyrotechnic charges used in gas generators for air-bags.
• the pyrotechnic charges useful for the implementation of the method of the invention have dimensions adapted to the intended operating time (ie greater than those of the pyrotechnic charges used in gas generators for air-bags). .
• This composition is advantageously optimized with reference to numerous parameters, such as the combustion temperature, the gas yield, the toxicity of the combustion gases and the pyrotechnic safety.
• composition of the at least one pyrotechnic charge which generates the pressurization gases during the implementation of the process of the invention, advantageously contains:
• At least one oxidizing component chosen from nitrates, such as basic copper nitrate, sodium nitrate, ammonium nitrate, perchlorates, such as ammonium perchlorate, potassium perchlorate, dinitroamides, such as dinitroamide; ammonium (DNA), and metal oxides, such as ferric oxide; and
• nitrates such as basic copper nitrate, sodium nitrate, ammonium nitrate, perchlorates, such as ammonium perchlorate, potassium perchlorate, dinitroamides, such as dinitroamide; ammonium (DNA), and metal oxides, such as ferric oxide; and
• At least one nitrogen reducing component chosen from guanidine nitrate, nitroguanidine, guanyl urea dinitramide, tetrazole, its derivatives and their salts, such as 5-aminotetrazole, 5-guanylaminotetrazole and the potassium salt of 5-aminotetrazole; , the sodium salt of 5-aminotetrazole, the calcium salt of 5-aminotetrazole, the ammonium salt of biterazole, the sodium salt of biterazole, the ammonium salt of biterazolamine, the sodium salt of 5, 5'-azobiterazole, calcium salt of 5,5'-azobitetrazole, triazoles, dinitramides, diamides and polyamine nitrates.
• nitrogen reducing component chosen from guanidine nitrate, nitroguanidine, guanyl urea dinitramide, tetrazole, its derivatives and their salts, such as 5-aminotetrazole, 5-guanylaminotetrazole and
• composition of the at least one pyrotechnic charge optionally contains, in addition:
• At least one ballistic catalyst advantageously chosen from oxides of copper, iron, manganese, cobalt, aluminum, titanium, zirconium, zinc and magnesium; and or
• At least one wetting agent advantageously chosen from organosilanes and titanates, very advantageously chosen from vinyltris- (2-methoxyethoxy) silane, tris- (3-trimethoxysilylpropyl) isocyanurate, ⁇ -glycidoxypropyltrimethoxysilane, diethoxydiacetoxysilane, diacetoxydiethoxysilane and dibutoxyethoxymethylsilane; and or
• At least one agglomerating agent advantageously chosen from silicon oxide and alumina; and or
• At least one manufacturing aid advantageously chosen from carboxylic acid, calcium stearate, silica and mica, and / or
• a binder advantageously chosen from oxygenated hydrocarbon binders containing an elastomer or a rubber and a plasticizer (such as in particular described in patent application EP 1 216 977), oxygenated hydrocarbon binders obtained by crosslinking an elastomer in the presence of a crosslinking agent and a plasticizer whose molecular mass is greater than 350 g / mol and the oxygen balance equal to or greater than -230% (such as in particular described in patent application EP 2 139 828), a binder PVC (polyvinyl chloride), a silicone binder, a cellulosic binder, a PVA binder (polyvinyl acetate).
• oxygenated hydrocarbon binders containing an elastomer or a rubber and a plasticizer such as in particular described in patent application EP 1 216 977
• oxygenated hydrocarbon binders obtained by crosslinking an elastomer in the presence of a crosslinking agent and a plasticizer whose molecular mass
• Pyrotechnic charges the composition of which contain such ingredients and may be used in the context of the implementation of the process of the invention, have been described in particular in the following patent documents: US 5,608,183, US 6 143 102, FR 2 975 097, FR 2 964 656, FR 2 950 624, FR 2 915 746, FR 2 902 783, FR 2 899 227, FR 2 892 117, FR 2 891 822, FR 2 866 022, FR 2,772,370 and FR 2,714,374.
• the pyrotechnic charges, useful for the implementation of the process of the invention, are obtained in a conventional manner, thus advantageously starting from the ingredients listed above.
• the process comprises the extrusion of a paste containing the constituents of the load.
• the process comprises a step of aqueous dissolution of all (or some of) constituents (said aqueous dissolution step comprising solubilization of at least one of said main constituents (oxidant and / or or reducing agent)), obtaining a powder by spray-drying the solution obtained, (optionally) adding to said powder component (s) which would not have been dissolved, and then the shaping of the powder by dry compression to obtain pyrotechnic objects.
• the pyrotechnic charges of the invention can also be obtained (directly) by a dry process.
• a dry process can be limited to a simple compression of the powder obtained by mixing the constituents, in order to obtain block disks.
• such a process may comprise roller compaction, followed by granulation, and then shaping the granules, to obtain objects. This variant is described in particular in patent application WO 2006/134311.
• the pyrotechnic charges useful for the implementation of the process of the invention can also be obtained according to other conventional methods comprising mixing in a kneader with pale or twin-screw a composition containing a binder for obtaining a paste, then extruding or casting said paste into molds to obtain objects.
• multi-component loadings generally two-component, they can result from the juxtaposition (of the stacking) of several loads prepared previously.
• the procedure is also conventional, for example by varnishing their surface to be inhibited.
• a type A loading of a pyrotechnic charge, which has the shape of a straight cylinder with a circular section with a lateral surface developing throughout its length between two end faces, one of its two faces being end and at least a part of its lateral surface from said end face being inhibited in combustion, the other of its two end faces not being inhibited in combustion and which consists of two juxtaposed sections, having different rates of combustion at a given pressure
• the first section of solid monolithic block type or stack type of structures, such as disks or cylinders, with an uninhibited end face in combustion corresponding to said end face uninhibited combustion of said right cylinder and a side surface corresponding to a portion of said lateral surface of said right cylinder, at least partially inhibited (charging t is then a load of type A "1) or not (the load is then a loading of type A" 2) in combustion, having a combustion speed at given pressure higher than that of the second section (due to different pressure coefficients and / or pressure
• Loads of this type (having an overall circular straight cylinder shape with a first single-component structure section) are perfectly visualized in FIGS. 3 and 4 below. We have here privileged the cylindrical form. These charges burn, according to the advantageous combustion mode "in cigarette” (see above).
• Figures 1, 1, 2, 3 and 4 show schematically, in section, pyrotechnic charges suitable for the implementation (of advantageous variants) of the method of the invention.
• Figures 1.1, 2.1 and 3.1 show schematically (without taking into account the ignition phase of the pyrotechnic charge) the evolutions of the gas flows (of combustion generated), pressures in the tank (of liquid) and flow of liquid (pressurized delivered ), during the implementation of the method of the invention with combustion of, respectively, the pyrotechnic charges of Figures 1 or 2 and 3.
• Figure 2.2 shows schematically the evolution of the combustion surface (Scombustion) during the combustion of the pyrotechnic charge of Figure 2.
• FIGS. 1A, 1B and 1C schematically show, in section, devices, loaded with the pyrotechnic charge of FIG. 1, and the liquid L to be delivered, suitable for the implementation of variants of the method of the invention.
• the loadings shown diagrammatically in FIGS. 1, 1, 2, 3 and 4 as well as the theoretical curves shown in FIGS. 1.1, 2.1 and 2.2 are, in a combustion context of said loadings where the temperature of the pressurization gases is constant. .
• FIG. 1 shows a pyrotechnic charge 7 of type A.
• This charge, of cylindrical shape, of length I, is a monolithic block. It is inhibited in combustion by the varnish 8 over its entire surface, except on one of its end faces.
• FIG. 1 shows a pyrotechnic charge 7 'of the same type, similarly inhibited, not monolithic, but consisting of a stack of several disks.
• Figures 1 and 1 show a constant combustion surface (corresponding to the surface of their circular section). They burn in frontal combustion (burning in "cigarette"). It is easy to understand that the flow of gas (combustion) generated is increasing then almost constant during the pressurization phase (the increasing combustion pressure) and then almost constant during the liquid delivery phase (at constant combustion pressure); Figure 1.1 shows schematically this temporal profile of flow. With regard to the pressure in the tank, it begins to increase until reaching the pressure at which the liquid is delivered (transient phase), the threshold pressure where the cap 3 is cleared (see Figures 1A to 1C). Beyond this threshold pressure, the pressure is constant. Under the effect of this constant pressure, the liquid is delivered at a constant rate.
• the devices shown are respectively referenced 100, 101 and 102. Their unitary structure (of one piece, monobloc) is respectively delimited by a body 100 ', 101' and 102 '.
• the devices 100, 101, 102 comprise a reservoir 1, enclosing the liquid L.
• Said reservoir 1 has a delivery orifice 2 (of said liquid L), closed by an erasable operculum 3 (for example of the frangible membrane type in the form of petals or spring valve).
• an erasable operculum 3 for example of the frangible membrane type in the form of petals or spring valve.
• the devices 100, 101, 102 comprise a pyrotechnic gas generator, respectively referenced 15 (Figure 1A), 16 (Figure 1B) and 17 ( Figure 1C).
• the generators represented are in fact of three types. Each of said generators contains a pyrotechnic charge 7 of the type shown in FIG. 1 (ie inhibited by the varnish 8 over its entire surface, except on its end face intended to be ignited by an ignition system (not shown)).
• reference 9a is made to the combustion chamber of the generator 15.
• This combustion chamber 9a corresponds to the expansion chamber 9'a of generated gases.
• the combustion chamber 9b is delimited by a nozzle 10 with a constant neck surface.
• Said nozzle 10 allows a "fine” adjustment of the pressurization gas flow rate in the expansion chamber 9'a and thus the pressure exerted on the piston 4 and thus the liquid delivery rate (during the "active phase") .
• combustion chamber 9C is connected to the gas expansion chamber 9'c through the pipe 11. It is also perfectly understood that such an arrangement allows the implementation within the generator 17 of a combustion at constant pressure (in "active phase” the volume of liquid delivered corresponding to the volume of gas generated).
• FIG. 2 shows a pyrotechnic charge 70 of type A '.
• the variation of said combustion surface is shown schematically in FIG. 2.2.
• the curves in FIG. 2.1 show the variation of the gas flow during the transient phase (the said flow rate decreases as the uninhibited lateral surface consumption is consumed) and then its constancy during the "active phase"("cigarettecombustion”).
• Figure 3 shows a 700 type A load.
• This loading 700 of cylindrical shape, length I, consists of two blocks (sections or parts) cylindrical 702 and 701 juxtaposed. It is inhibited by the varnish 800 on one of its end faces 700c and over its entire lateral surface 700a. It is not inhibited on its other end face 700b which also corresponds to the end face 701b of the block 701.
• the combustion of said charge, successively its constituent blocks 701 and 702 is therefore a "cigarette combustion", successively during the transient phase and during the "active phase".
• said block 701 has a combustion rate Vci (P) greater than the combustion rate Vc 2 (P) of the block 702.
• FIG. 3.1 shows the constancy of the gas flow rates during the two successive phases ("cigarette" combustion), the flow rate during the transient phase increasing and then becoming greater than the flow rate during the "active phase", due to Vci> Vc 2 .
• the reservoir pressure increases rapidly during said transient phase. Then observed (“during the active phase”) the constancy of said pressure and therefore that of the delivered liquid flow.
• FIG. 4 shows a load 700 'of type A' 2.
• This figure shows the references of FIG. 3 with a "'", in fact the referenced elements of FIGS. already understood that the only difference between the loadings of FIGS. 3 and 4 (both of cylindrical shape) is the non-inhibition in combustion of the lateral surface 701'a of the block 701 'with a combustion rate Vci, with Vci (P)> Vc 2 (P), the combustion of the block 701 'is therefore frontal and lateral (just like that of the first part of the load 70 of FIG 2)
• Vci Vci
• Vc 2 Vc 2

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