FR2714457A1 - Explosive aerosol head with a dispersion column - Google Patents

Abstract

An explosive aerosol head comprises a dispersion unit consisting of a reservoir (14) for fuel enclosing a dispersion column which consists of an explosive charge (9) and a priming system. Firing information is transmitted by the priming system which is attached to one part of a pipe (1) filled with explosive, part embedded in the explosive charge. The priming system consists of the pipe (1) formed by a tubular unit with interior cross-section 0.1-1 mm<2>, mfd. of a material with mechanical strength greater than that of Pb, and chemically resistant to the explosives used. This is charged by injection under pressure with a composite explosive (3) and has a thickness sufficient to support the injection pressure of the explosive. The priming unit is formed by a widened unit (2), attached to the end of the tubular unit and moulded from a casting of a compsn. (5) of composite polymer explosive.

Description

Explosive aerosol head

The present invention relates to an explosive aerosol head.

The principle of operation of explosive aerosol heads (referred to as TAE in what follows) consists in causing the detonation of an explosive cloud previously formed by dispersion of a fuel.

in the air.

TAEs can be placed at ground level. The effects of the former

plosion thus obtained are significant but of low range: it is difficult to overcome this drawback because of the small room for maneuver available to modify the conformation of the cloud at

from a head placed at ground level.

We were therefore led to design heads dropped from aero-

naves or carried by a missile or rocket which are

detonating above ground level, which considerably increases

the extent of their effects. However the achievement of deto-

gaseous nations is considerably complicated in this case. Indeed the possibilities of conformations of the detonable cloud are then very numerous and the correlative effects on the ground very variable. In addition, the problem of cloud priming cannot then be solved in the same way as in statics because of the speed component

due to the movement of the head.

Heads have been proposed consisting of a ballistic stage comprising

both in particular means of guiding, stabilizing and braking

nage, of a dispersion stage comprising a cylindrical tank containing the fuel and axially, an explosive column capable of dispersing the fuel, of a priming stage comprising means for ejecting priming grenades into the cloud and a detection and firing stage comprising means for transmitting the signal of the dispersion and then of the initiation of the cloud at a predetermined altitude. Such heads and such devices

constituents of TAE are described, for example, in the US patents.

ricans 3,940,443, 3,940,995 and 3,999,482 and are used in particular in bombs, missiles and rockets. Aerosol explosive. The

central dispersion column is initiated by priming systems

conventional ices such as detonating cord systems - available

time delay devices - explosives relay.

These initiation systems require mechanical assembly by contact (hole left at the end of the explosive column for the passage of the initiation system) hence the disadvantage of junction faults (mechanical play for example). In addition, these systems are relatively

voluminous, which limits, for a given volume, the quantity of ex-

plosive of the dispersion column therefore its efficiency.

The present invention makes it possible to remedy these drawbacks. In

Indeed, the Applicant has now produced an explosive aerosol head.

sif equipped with a system for initiating the dispersion column, having a small volume and allowing a very reliable initiation of the explosive thanks to an intimate contact between the system and the explosive. This new initiation design makes it possible on the one hand to initiate the explosive, for example in the heart of the column and on the other hand to satisfy the

handling and transport constraints of the TAE.

The invention relates to a TAE, comprising in particular a disper-

ion consisting of a fuel tank containing, generally axially in a central position, a dispersion column, said dispersion column comprising a pourable explosive charge and a priming system allowing the transmission of the firing order, this system of 'initiation comprising a channel filled with explosive, at least partly embedded in the explosive charge and an initiation means fixed to the aforementioned channel and embedded in the explosive charge, characterized in that said initiation system consists of: - by said channel formed of a tubular element with an internal section of between 0.1 and 1 mm2, made of a material having a mechanical resistance greater than that of lead and resistant

chemically to the explosives used, filled by injection under pressure

of a composite explosive and of sufficient thickness to

be able to withstand the injection pressure of the composite explosive.

- by said priming means consisting of a flared element, fixed to the end of the tubular element and overmolded with a mass in

polymerized composite explosive.

Lead has insufficient mechanical strength to support

ter the injection pressure of the composite explosive.

The choice of a material having a higher mechanical resistance than that of lead makes it possible to produce a channel of very small section.

and thus considerably reduce the bulk of the control system.

coding within the dispersion column.

In general, the aforementioned initiation system of the dispersion column has no lateral pyrotechnic and mechanical effects on the pourable explosive charge of said column (initiation system of the dispersion column.

low energy).

The inner section of the tubular member may have a shape

any. It can be for example circular, elliptical, poly-

gonal, rectangular, square.

According to a preferred embodiment, the tubular element is a cylinder

with an internal diameter of between 0.3 and 0.8 mm.

The tubular element is generally metallic, but a tubular element

plastic material sufficiently resistant mechanically and chemically to the explosives used may also be suitable. Also suitable are tubular elements resulting from the assembly of several materials, for example a metallic tubular element coated internally with a plastic material, such as a fluoropolymer. Particularly preferably, the tubular member is made of stainless steel, has an internal diameter of between 0.4 and 0.7 mm and has

an outer diameter of between 0.55 and 2.7 mm.

Stainless steel is chosen to be very chemically and mechanically resistant.

nically. Thanks to this material, it is possible to use an element

tubular of small diameter.

The tubular member is filled with a composite explosive preferably containing between 73% and 82% by weight of powdered pentrite and

between 27% and 18% by weight of an organic binder.

Preferably, the pentrite has a particle size of

between 1 and 7 microns.

Also preferably, the organic binder is chosen from

group consisting of polysiloxanes and polyurethanes.

The flared element of the starting means is fixed, welded for example, by its narrowest part to one end of the tubular element. He

is generally made of the same material as the tubular element.

When the tubular element is cylindrical, this flared element is of

preferably frustoconical.

The interior of this flared element is filled with the same explosive compound.

site than that contained in the tubular element, no discontinuity

must not exist within this explosive.

This flared element is molded with a composite explosive mass

polymerized. The composition of this composite explosive can be identified

tick but is generally different from that of the injected explosive

in the channel and the flared element of the priming means.

To best perform its function in the means of initiation, the explosion

the aforementioned polymerized composite sif must be easily startable, and

must have good priming power as well as a transi-

weak detonation range.

Such composite explosives consist for example of a polymeric binder such as polyurethane, polysiloxane or polybutadiene charged with pentrite and optionally, in addition to pentrite, with one or more other reinforcing charges in secondary explosive,

such as octogen or hexogen.

Preferably, a polymerized composite explosive containing

closing 10% to 80% by weight of a polymeric binder and from 10% to 90% by weight of a charge of secondary explosives containing at least

pentrite.

The polymerized composite explosive may also contain various additives.

tifs such as metals and / or metal salts. Partially

most preferably, a polymerized composite explosive is used

containing 77% of pentrite and 23% of a polyurethane binder.

The volume of the mass of polymerized composite explosive overmolding the flared element of the initiation means is at most of the order of

a few cm3.

The shape of this mass is a function of the regions that we want to pri-

vilégier within the dispersion column. Cubic, cylindrical, spheroidal faceted shapes can be considered, depending on the case,

frustoconical, etc ...

When one wants to carry out a priming in all directions which is generally the case, the shape of this mass is preferably

spheroidal, with a diameter for example close to 20 mm.

The tubular element can be partially embedded in an inert body to stiffen the priming system and / or maintain the mechanical properties of the system during firing. Such inert bodies

are for example expanded materials or not: synthetic, vegetal

tales, mineral, metallic.

According to a preferred variant, a TAE according to the invention is characterized

ized in that the initiation system of the dispersion column also comprises an integrated device, fixed in the mass of polymerized composite explosive of the initiation means, allowing the positioning of the initiation system in the container used for the production of the dispersion column. In many cases, it is not possible to use an external support to hold the

priming system in the container, hence the interest of this

laughing. This device can have many shapes and profiles

production: hooks, fins, flats, tubes, etc.

so many various and varied curvatures and curves (U, S, spiral, etc ...). It can be attached to any place in the

mass of polymerized composite explosive.

To ensure its function of positioning the priming system in the container used for the realization of the dispersion column, the

aforementioned device must be in contact with the walls of said container.

This contact surface can be any. This device must also exert a slight pressure, via this contact surface, on the walls of the container. It must therefore be made of a material having a certain elasticity (metals, polymerizable materials, etc.). In some cases, these are the

walls of the container which exert a slight pressure on the

sitive.

It goes without saying that the dimensions and in particular the length of said

sitive depend on the size of the container and the position

desired from the priming system in the container.

The number of hooks, fins, flats, tubes, etc ... can be

variable. It is usually 2, 3, 4 or 5.

The aforementioned integrated device is preferably made up of a-

very soft and elastic straps, which allows for example the introduction of

reduce the priming system to a disperse column container

sion whose only means of access is a small diameter tube (20 to 30 mm for example). The fins are folded back in contact with the tube during introduction and then unfold into the container, thus ensuring that the priming system is maintained by contact of the fins with the

container walls. The length of the fins depends on the posi-

required tation. The fins are in this realization

preferred made of a metallic material or not having a coef-

elasticity factor of at least the order of 1%, for example in steel

Z2NXDT 18-10-7 according to French standard, so that they represent

their initial shape after the bending imposed during passage through the orifice. Particularly preferably, these fins have two arches and are in the form of hooks. This shape ensures excellent contact with the walls of the container and good retention of the priming system when the fins are unfolded and allows the fins to bend as far as possible along the mass of polymerized explosive when the device is to be introduced into a

narrow way.

A particularly desirable positioning of the priming system is centering (for example on the axis of the column). In that case

the fins are generally identical and one uses in a pre-

fairy, three fins forming between them an angle of 120 degrees.

The dispersion column of a TAE according to the invention can be produced.

read by first assembling the various elements of the priming system. To do this, a tubular element of the desired dimensions is produced to begin with, for example by cutting from a tube. The flared element of the starting means is then fixed by its narrowest part (of section close to that of the tubular element) to one of the ends of the tubular element by welding

for example.

A composite explosive with a liquid organic binder is then injected under pressure into the assembly produced previously. For this, we first create a vacuum, then, after degassing the explosive composition to avoid any bubbles, we inject the explosive such as pentrite in suspension in a preferably organic binder such as

as polyurethane or polysiloxane in liquid state.

To obtain perfect filling, it is essential that the injection be carried out under a very high pressure, for example between 400 and 1000 bars. The flared element is then overmolded with a mass of composite explosive. To do this, the end of the tubular element is placed with the flared element of the starting means in a mold, the internal shape of which is that chosen for the mass in

composite explosive.

When an integrated positioning device is to be fixed in said mass, it is also placed in the mold so that the part to be embedded in the composite explosive is in the mold cavity. An explosive is then injected into the mold

composite in the uncrosslinked state under a pressure of a few bars.

The composition is then polymerized, for example by the thermal effect.

mique. After demoulding, to make the central dispersion column, the

priming system is then placed in the container of said co-

lonne. This container is generally metallic.

The priming system can be positioned very precisely and reproducibly thanks to the integrated positioning device. It is

thus possible to manufacture, in large series, identical loads.

ticks with strictly similar performance.

The explosive charge is then introduced, for example by casting into the container, the shape of which it takes, then the polymer is made to polymerize.

explosive charge.

When a part of the tubular element not embedded in the explosive charge must be embedded in an inert body to stiffen the

initiation system, for example the inert composition is poured into

respondant which is then polymerized. The non-limited examples

The following tatives illustrate the foregoing description.

Figure 1 shows, in longitudinal section, the priming system

of the dispersion column of a TAE according to the invention.

FIG. 2 represents this same system in top view.

FIG. 3 represents, in longitudinal section, the column of dis-

persion of a TAE according to the invention.

Figure 4 shows, in longitudinal section, a TAE according to the in-

vention. FIGS. 1 and 2 represent the system for initiating the dispersion column of a TAE according to the invention. It comprises a channel (1) formed by a cylindrical tubular element, in stainless steel, cut to the desired length in a tube of internal diameter.

0.7mm and outside diameter 1.2mm-.

The flared element (2) of the starting means has been welded by its part la

narrower, the diameter of which is close to that of the tubular element.

lar, at one end of the tubular element. Another flared element (4) has been welded in the same way At the other end of the element

tubular to ensure the connection with the detonator.

A composite explosive (3) containing a liquid polyurethane binder, degassed beforehand, and comprising 80% by weight of powder pentrite (particle size 45 microns) and 20% by weight, was then injected under pressure into the assembly thus produced and placed under vacuum. polyurethane binder. The density of this composite explosive is equal

At about 1.5 g / cm3 and its detonation speed of the order of 7500 m / s.

The flared element (2) was then overmolded with an exploding mass (5).

polymerized composite sif of composition 23% by weight of poly- binder

urethane and 77% by weight of pentrite.

To do this, we placed the end of the tubular element with

the flared element (2) of the starting means in a mold of internal shape

spheroidal top, interior volume of about 4 cm3. Three ai-

Z2 NKDT 18-10-7 aged steel slats (6) according to French standard were also placed in the mold, each 120 degrees from the other, and so that the end to be embedded in the part

top of the mass (5) or in the mold cavity.

The three fins are identical and have 2 camber, which

set them up in a hook shape.

Was then injected into the mold, under a pressure of 4 bars, the

the above-mentioned composite explosive composition, unpolymerized.

After polymerization by thermal effect, then demolding, one obtains

the priming system. In figure 1 the fins (6) are shown

felt unfolded (solid lines (6)) and folded as far as possible along

the mass (5) (dashed lines (7)).

In the unfolded position, each hook-shaped fin has 3

parts (6a) (6b) and (6c). Part (6a) is fixed on approxima-

tively half of its length in the mass (5). Part (6b) is perpendicular to the axis of the tubular element and part (6c) has a length close to that of part (6a). The parts (6a)

and (6c) form an angle of about 120 degrees with part (6b).

In the maximum folded position (7), the position of the part (6a) remains practically identical. The part (6b) on the other hand takes a position (7b) tangential to the mass (5), the part (6c) taking the position (7c) where its free end practically comes into contact with

the tubular element.

FIG. 3 represents the dispersion column of a TAE according to the invention using the preceding priming system, represented in FIGS. 1 and 2. The dispersion column is in the form of a main cylindrical cavity (9) filled with a castable composite explosive of conventional composition: 48% lead nitrate, 40%

hexogen and 12% of an organic binder.

This cavity (9) is delimited by the walls (8) of length approximately 600 mm and of internal diameter approximately 60 mm and communicates with a second cylindrical cavity (12) filled with an inert material, having the same axis (13) as the cavity (9), but having an internal diameter

lesser, of the order of 25 mm, the length being approximately 300 mm.

Access to the cavity (9) can only be done through the cavity (12). To produce this dispersion column, the priming system shown in Figures 1 and 2 was therefore introduced into the cavity (9) by passing

in the cavity (12).

In contact with the walls (10) of the cavity (12), the fins (6) are

are folded and positioned in a position close to that pre-

sent in (7) Figure 1 and described above.

The system thus slides along the walls (10), the diameter of the mass (5) being slightly less than the diameter of the cavity (12), to reach the cavity (9). At this moment, the fins (6) unfold and come into contact with the walls (8) of the main cavity (9), at the level of the entire surface of the part (6c) of the fins (refer to figure 1). The system, still located in the axis (13) of the cavities (9) and (12), thus slides to the position

desired along this axis (13).

The fins (6) make it possible to maintain and perfectly center the mass (5) and the tubular element on the axis (13) of the two cavities (9)

and (12).

The cavity (9) was then filled with the aforementioned castable composite explosive, then, after polymerization of this explosive, the cavity (12) with an inert material. The initiation system (11) was then connected. FIG. 4 represents a TAE according to the invention. This TAE presents:

- a dispersion stage consisting of a reservoir (14) con-

holding about 60 1 of fuel (15) (propylene oxide) and axially enclosing, in a central position, the dispersion column shown in figure 3. This dispersion stage comprises 2 deflectors (16 and 17) having substantially the same symmetry elements as '' a section of the tank (14) in a plane perpendicular to the axis of the central dispersion column and determining an unsealed partition between the central part of the tank (14) and the volumes delimited by the bottom (18) and the ceiling (19) of said reservoir (14); - an initiation stage containing a device (20) known per se for ejecting grenades intended for the initiation of the detonation

sparkling. This priming stage further comprises pyrotechnic means.

niques to initiate substantially simultaneously the device (20) and a device for timing a pyrotechnic signal (26) for firing the central dispersion column. These pyrotechnic means comprise a detonating transmission cord (21) coming from the detection stage (22). This cord ends in a pyrotechnic distributor (23) from which, on the one hand, a detonating transmission cord (24) emerges towards the device (20) for ejecting the grenades and

on the other hand a detonating transmission cord (25) to the dis-

positive pyrotechnic signal delay (26). This device (26) makes it possible to initiate at the output a detonating transmission cord (27) connected to the tubular element of the initiation system of the central dispersion column;

- a target detection stage (22).

At time to, in contact of the target detector (28) with the ground, in a manner known per se, the set of means included in the stage of

target detection (22) caused the detonation cord to fire.

transmission gear (21). the detonation wave reached the distributor (23) which simultaneously initiated, using the cords (24) and (25), the delay device (26) and the grenade launcher (20). The grenade was then ejected. During this time, the delay device (26) operated and while the grenade was ejected, the transmission cord (27) transmitted the order to fire to the priming system of the central dispersion column. The detonation front progressed within the explosive contained in the tubular element then in the flared element (2) which was at its end, without initiating the explosive charge (9) in which the system was embedded. initiation, the small amount of explosive

as well as the thickness of the walls not allowing such an ini-

lateral tiation.

The mass (5) of polymerized composite explosive of the initiation means which

overmolded the flared element was then initiated, then initiated it-

even the initiation of the explosive charge (9). The spheroidal shape of

the mass (5) ensured priming in all directions.

of the explosive charge (9).

The fuel (15) was then dispersed, guided and protected in its movement by the deflectors (16 and 17). The explosive aerosol cloud was formed in an area of the atmosphere through which the grenade ejected from the grenade launcher (20) was passing as it detonated.

and the cloud detonation occurred.

The grenade was put into operation at time to + 0.1 ms. The grenade was ejected at time to + 5 ms A approximately

m / s and exploded at time to + 80 ms.

The detonation of the central dispersion column took place at time to + 15 ms. The cloud, which was suitably dispersed at the end

from to + 60 ms, detonated at time to + 80 ms.

Claims (17)

Claims 1. Explosive aerosol head comprising in particular a dispersal stage ion consisting of a fuel tank (14) containing a dispersion column, said dispersion column comprising an explosive charge (9) and a priming system allowing the transmission of the firing order, this ignition system comprises taking a channel (1) filled with explosive, at least partly embedded in the explosive charge (9) and a priming means attached to the aforementioned channel (1) and embedded in the explosive charge (9) characterized in that said priming system consists of: - said channel (1) formed by a tubular element of cross section between 0.1 and 1 mm2, made of a pre- feeling a mechanical resistance greater than that of lead and chemically resistant to the explosives used, filled by injection under pressure with a composite explosive (3) and having a thickness sufficient to be able to withstand the injection pressure of the ex- composite plosive; - by said priming means consisting of a flared element (2) connected to the end of the tubular element and overmolded with a mass (5) in polymerized composite explosive. 2. An explosive aerosol head according to claim 1 characterized in that the initiation system of the dispersion column also comprises an integrated device fixed in the mass (5) in explosive. polymerized composite of the initiating medium, allowing the position- the priming system in the container used for the realization sation of the dispersion column. 3. An explosive aerosol head according to claim 1 or 2 characterized in that the tubular element is a cylinder with an internal diameter of between 0.3 and 0.8 mm and in that the flared element (2) of the means priming connected to the end of the tubular element is frustoconical. 4. An explosive aerosol head according to any one of claims 1 A 3 characterized in that the tubular element is made of stainless steel dable, in that it has an inner diameter of between 0.4 and 0.7 mm and in that it has an outer diameter of between 0.55 and 2.7 mm. 5. An explosive aerosol head according to any one of claims 1 A 4 characterized in that the mass (5) of composite explosive polymerized starting medium has a spheroidal shape. 6. Explosive aerosol tgte according to claim 2 characterized in that the integrated device allowing the positioning of the priming system in the container used for the realization of the column dispersion consists of fins (6). 7. Explosive aerosol head according to claim 6 characterized in that the fins (6) allowing the positioning of the initiation system in the container used for the realization of the dispersion column have two curvatures and are in the form of hooks. 8. Explosive aerosol tgte according to claim 2 or 6 characterized in that the integrated device allowing the positioning of the initiation system in the container used for the realization of the dispersion column allows the centering of said priming system. 9. An explosive aerosol head according to claim 8 characterized in that the integrated device allowing the centering of the breaking consists of three fins (6) forming between them a 120 degree angle. 10. An explosive aerosol head according to any one of claims 6, 7 and 9 characterized in that the fins (6) are made of a material having a coefficient of elasticity at least of the order from 1%. 11. An explosive aerosol head according to any one of claims above, characterized in that the explosive composition comprises site injected into the tubular member contains from 73% to 82% by weight pentrite powder and from 27% to 18% by weight of an organic binder fuck. 12. An explosive aerosol head according to claim 11 characterized in that the pulverulent pentrite has a particle size ranging from between 1 micron and 7 microns. 13. An explosive aerosol head according to claim 11 or 12 charac- terized in that the organic binder is chosen from the group consisting of titué by polysiloxanes and polyurethanes. 14. An explosive aerosol head according to any one of claims above characterized in that the mass (5) of polymerized composite explosive of the initiating means contains from 10% to 80% by weight of a polymeric binder and from 10% to 90% by weight of an explosives charge secondary containing at least pentrite. 15. An explosive aerosol head according to claim 14 characterized in that the polymeric binder of the mass (5) of polymerized composite explosive of the initiating means is chosen from the group consisting of by polyurethanes, polysiloxanes and polybutadienes. 16. An explosive aerosol head according to claim 14 characterized in that the charge of the mass (5) of polymerized composite explosive of the priming medium is only pentrite. 17. explosive aerosol head according to claim 14 characterized in that the mass (5) of polymerized composite explosive of the priming means cement contains 23% by weight of a polyurethane binder and 77% by weight of pentrite.