EP0916068A1

EP0916068A1 - Laser initiated simultaneous ignition system

Info

Publication number: EP0916068A1
Application number: EP97942841A
Authority: EP
Inventors: Rainer Hagel; Bernd Krause; Klaus Redecker; Wolfram Seebeck
Original assignee: Dynamit Nobel AG; Dynamit Nobel GmbH Explosivstoff und Systemtechnik
Current assignee: Dynamit Nobel AG; Dynamit Nobel GmbH Explosivstoff und Systemtechnik
Priority date: 1996-08-02
Filing date: 1997-08-01
Publication date: 1999-05-19
Anticipated expiration: 2017-08-01
Also published as: DE19719273A1; WO1998005918A1; ATE208486T1; DE59705292D1; EP0916068B1

Abstract

A laser initiated simultaneous ignition system comprising at least one ignition charge and/or one propellant charge module (15) containing explosive material (16). Along the pathway of the laser beam (23, 23') an outcoupling device (18) is assigned to outcouple at least one part of the laser beam, which when the laser beam (23, 23') is incident, causes ignition of the ignition charge or the explosive material in the propellant charge module.

Description

Laser initiated simultaneous ignition

The invention relates to a laser-initiated simultaneous ignition system with at least one ignition charge and / or an explosive propulsion module.

Various methods for initiating, ie igniting, ignition charges or explosives by means of laser light are known from the prior art. Here, the laser beam can be directed via a light guide directly or via a downstream focusing optics focused on the primer charge or directly on the explosive or the primer charge. With general conditions matched to laser initiation, the ignition process can be started with relatively low laser energy. In the case of an ignition system for a plurality of drive modules or ignition charges, at least one light guide is guided to each drive module or each ignition charge, with each light guide being operated simultaneously is fed with appropriate laser light and the ignition charges or drive modules are thereby ignited at the same time.

Under unfavorable mechanical and spatial conditions, for example in the cargo space of a self-propelled howitzer, this ignition system is not suitable because of its space requirement and its sensitivity and for reasons of cost.

The object of the invention is to provide a simplified and improved laser-initiated simultaneous ignition system.

This object is achieved by the features of claim 1.

In the ignition system according to the invention, a decoupling device is arranged along the beam path of a laser beam for decoupling at least a part of the laser beam or light. When the laser beam strikes, the ignition charge or the explosive of the drive module is ignited by the decoupling device. The decoupling device couples so much light energy from the laser beam that it is sufficient to ignite the explosive or the ignition charge. Each ignition charge or drive module along the optical axis of the laser beam is lit approximately simultaneously. Since no light guides are used to supply the laser light, a very simple, compact and reliable simultaneous ignition system is created. The location of the drive modules or ignition charges, ie their distance and position to the laser light source, can vary without thereby reducing the ignition safety.

Each drive module or each ignition charge preferably has an ignition channel in which the decoupling device is arranged. The drive modules or ignition charges can be arranged in such a way that the ignition channels form a single straight and continuous channel for the laser beam. With this arrangement, a plurality of primer charges or drive modules can be arranged in a line and ignited approximately simultaneously, for example in the cargo space of a self-propelled howitzer.

In a preferred embodiment, a part of the laser beam or light is coupled out simultaneously from each coupling-out device, i.e. neglecting the speed of propagation of the light, the laser light falls on all decoupling devices simultaneously, as a result of which the drive modules or ignition charges are also ignited simultaneously.

The decoupling device can be an optical element that deflects part of the laser beam or light onto the explosive or the ignition charge. This can be an optically partially transparent element that reflects only part of the incoming laser beam and lets the rest of the beam cross-section pass unchanged to the next drive module or ignition charge; or it can be a mirror that deflects only a part, for example a sector of the laser beam, onto the explosive or the ignition charge. In another embodiment, however, the decoupling device can also be designed as a pyrotechnic element which is struck by at least part of the laser beam, as a result of which it is ignited and in turn ignites the explosive of the respective drive module or the ignition charge. A very inexpensive solution can be realized by using pyrotechnic elements.

The pyrotechnic decoupling device can also be designed such that it only fades out part of the laser beam, so that the remaining part of the laser beam can pass through the respective ignition channel and strike the decoupling devices of the following drive modules or ignition charges and ignite them.

In a first embodiment, the pyrotechnic outcoupling device is ring-shaped, the outcoupling device no longer blanking out the laser beam in this area only after igniting and burning off at least part of the inner circumference of the ring, whereupon the laser beam falls on the outcoupling ring of the following drive module or the following ignition charge .

It is particularly advantageous if the inner part of the ring has a small axial length, ie has less substance and is therefore more easily flammable and burning. As a result, the inner part burns off very quickly, so that the laser beam can ignite the inner circumferential ring of the decoupling ring of the following drive module or the following ignition charge after a short time. In another embodiment, the pyrotechnic outcoupling device has a part projecting into the center of the ignition channel, so that this part of all outcoupling devices can be detected simultaneously by the laser beam. For this purpose, these parts must be arranged so that they do not completely shade another protruding part of another drive module. As a result, an inexpensive and easily produced pyrotechnic ignition technology can be used to ignite almost all of the drive modules or ignition charges at the same time.

In a preferred embodiment, the pyrotechnic decoupling device is an explosive-coated film, for example a plastic film.

The explosive of the film and / or the propulsion module is preferably selected or modified such that it has a high degree of absorption in the region of the wavelength of the laser light. As a result, the minimum laser energy for igniting the explosive of the drive module or the film is reduced, so that it can be ignited with a lower energy density and with a miniaturized laser system.

Several exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Show it:

La a laser-initiated ignition system with five distributed ignition charges, 1b shows a second embodiment of a laser-initiated ignition system with six drive modules, each of which has an optical beam splitter as a coupling-out device,

2 is a top view of an annular pyrotechnic coupling-out device,

3 shows the decoupling device of FIG. 2 in longitudinal section,

4 shows the pyrotechnic outcoupling device of FIG. 2 in cross-section with the inner peripheral edge ignited and partially burned,

5 shows a longitudinal section of the pyrotechnic outcoupling device of FIG. 2 with a partially burnt-off inner peripheral edge,

6 shows a further embodiment of a pyrotechnic coupling device with a triangular ring cross section,

7 shows a further embodiment of a pyrotechnic outcoupling device in cross section with a wedge-shaped ring cross section,

8 shows a further embodiment of a pyrotechnic decoupling device with a part that protrudes toward the center of the circle,

9 shows a further embodiment of a pyrotechnic coupling-out device with a web projecting radially inwards, 10 shows a further embodiment of a pyrotechnic decoupling device with a web forming the circular diameter,

11 shows a further decoupling device of a pyro-technical decoupling device with a continuous web not running through the center of the circle,

12 shows a further pyrotechnic outcoupling device with a segment projecting into the ignition channel, and

13 shows a cross section of an embodiment of the ignition system with pyrotechnic decoupling devices of FIG. 12.

The arrangement of a laser-initiated ignition system with five ignition charges 27 is shown in principle in FIG. A laser device 22 'emits a laser beam 23', which is deflected several times via four partially transparent mirrors 18 'and finally strikes the ignition charge 27 arranged last. The partial beams 25 ', which are not reflected by the mirrors 18' but pass through, also strike the ignition charges 27, as seen from the incoming laser beam 23 ', which are located behind the mirror 18'. The partially transparent mirrors 18 'thus form decoupling devices through which each Part of the light of the laser beam 23 'is coupled out to ignite the respective ignition charge 27, the energy density of the outgoing partial beam 25' being sufficient to ignite the respective ignition charge 27. FIG. 1b shows the cargo space 10 of a gun, at the open end 11 of which a gun barrel (not shown) with a projectile connects. In the cargo space 10 formed by a tube 12, six ring-like explosive propulsion modules 15 are arranged one behind the other. At its center, each drive module 15 has a continuous ignition channel 14. Each drive module 15 consists of an explosive ring 16, the inner circumference of which is lined with an ignition sleeve 17 which surrounds the ignition channel 14. A glass plate 18 is arranged in the ignition sleeve 17 as an optical decoupling device and is set at approximately 45 ° to the longitudinal axis of the ignition channels 14. The glass plate 18 forms a partially transparent mirror for laser light fed into the ignition channels 14.

Instead of the glass plate 18, a transparent film, a prism or a partially transparent mirror can also be used as the optical beam splitter.

The ignition modules 15 are arranged one behind the other in such a way that their ignition channels 14 form a single straight and continuous channel for a laser beam. At the closed end of the cargo space 10, a laser device 22 is arranged in a termination block 21 such that its optical axis lies in line with the longitudinal axes of the drive modules 15. The laser beam 23 emanating from the laser device 22 thus runs on the optical longitudinal axis of the ignition channels 14 .

The glass plates 18 act as optical beam splitters, each of which couple out part of the laser beam light. The laser 22 forms together with the special Drive modules 15 a laser-initiated simultaneous ignition system.

Instead of through the laser device 22, the laser light can also be fed into the ignition channels 14 through a light guide. The parallel laser beam is expanded and has a diameter of a few millimeters. In other embodiments, the laser beam can also be focused or divergent.

To ignite the drive modules 15, the laser device 22 outputs a short, high-energy laser pulse which passes through the ignition channels 14 of the drive modules 15. An approximately 15% light portion of the laser beam is reflected radially outwards through the glass plates 18 in the ignition channels 14, where the reflected beam 25 ignites the igniter sleeve 17. The igniter sleeve 17 in turn ignites the explosive ring 16. The laser beam 23 strikes all glass plates 18 of the drive modules 15 at the same time, which is why the drive charges 15 are all ignited simultaneously.

In Figs. 2 to 13 show exemplary embodiments in which the initiation, ie the ignition, of the propellant charges is carried out not by an optical element but by a pyrotechnic element. The figures 2 to 12 show exclusively pyrotechnic decoupling devices without an explosive ring surrounding them. The pyrotechnic outcoupling devices are each instead of the optical outcoupling devices. Direction of the drive module of Fig. lb used in the explosive ring 16.

In Figs. 2 to 5 show the simplest embodiment of a pyrotechnic decoupling device 30. This decoupling device 30 consists of a cylindrical ignition ring 31, in the middle of which a free continuous channel 32 is arranged.

When the laser beam 23 strikes, the ignition ring 31 is ignited at the end of its inner peripheral edge facing the laser light and burns from the inside to the outside. The inside diameter of the channel 32 increases in such a way that the laser beam 23 falls on an ignition ring 31 'located behind it and also ignites it. This process takes place so quickly that these pyrotechnic decoupling devices 30, 30 'are ignited approximately simultaneously, so that the explosive rings are also ignited approximately simultaneously.

In Figs. 6 and 7 show further rotationally symmetrical pyrotechnic decoupling devices 30, 30 ₂ , each consisting of an ignition ring 35, 40. 6 has the ring cross-sectional shape of an equilateral triangle with an inwardly pointing tip, the ignition ring 38 of FIG. 7 is wedge-shaped in its cross-sectional profile. Common to both igniter rings 35, 38 is that the axial thickness of the inner peripheral edge of the igniter ring 35, 38 is very small on the inside and only increases towards the outside. This will cause the inner part of the ignition ring to burn quickly. ges and thereby in turn ensures a quick ignition of the subsequent ignition ring (s).

In any case, the laser beam must have a larger diameter than the inner, material-free area of the pyrotechnic ignition devices.

In Figs. 8 to 11 show pyrotechnic ignition rings which are not rotationally symmetrical but asymmetrical and in which a segment-like part projects into the ignition channel or the laser beam cross section. All these decoupling devices have in common that several such decoupling elements can be arranged one behind the other without shading each other. This ensures that the laser beam, with the correct arrangement of the ignition rings, falls simultaneously on a plurality of ignition rings arranged one behind the other, which in turn ensures simultaneous ignition of the decoupling devices and thus the explosive of the drive modules.

In the decoupling device 39 _x of FIG. 8, a circular sector-like part 41 protrudes in one piece from the outer ring 40 to the center.

In the embodiment of the decoupling device 39 ₂ shown in FIG. 9, a web-like part 42 projects radially inward from the outer ring 40.

In the embodiment of FIG. 10, a web 43, which passes through the center and forms the diameter, divides the ignition channel 14 of the pyrotechnic coupling-out device 39 ₃ into two halves. Another pyrotechnic igniter 39 ₄ is shown in FIG. 11. A web 44 crossing the ignition channel 14 connects two points of the outer ring 40 in such a way that it asymmetrically divides the ignition channel 14 into two parts.

FIG. 12 shows a further embodiment of a pyrotechnic outcoupling device 39 ₅ , in which the outer ring 40 is supplemented by a segment-like part 43 projecting inwards.

The in Figs. 2 to 12 pyrotechnic igniters shown are realized in the form of a tablet, but can also be designed as a film.

In particular the pyrotechnic decoupling devices 39 ₁ -39 ₅ of FIGS. 8 to 12 can also be designed as a thin film coated with magnesium. Furthermore, the film can be coated with a colorant or graphitized explosive, as a result of which the degree of absorption for the incident laser light can be increased. It is also possible to use thin foils on a plastic carrier with a conventional ignition mixture made of lead triresorcinate, AZM, black powder, etc., possibly with a burn accelerator or a primary igniter. Explosives tuned to the laser wavelength with a high degree of absorption of the laser light and a low initiation energy can also be used.

By selecting suitable beam guidance optics or by deflecting the light beam, the beam diameter can also be reduced and the energy density, which is important for safe initiation, can be increased. for example by an annular instead of a disc-shaped beam structure. The explosive exposed to the laser light should be selected in such a way that rapid erosion and good erosion of the erosion is ensured.

Since the axial position of the drive modules, for example in the cargo space of a self-propelled howitzer along a 1-meter long axis, can be arbitrary and the number of drive modules can vary, the drive modules that can be initiated by a laser beam pulse are ideal for such applications as a variable ignition system created. For the ignition, no focused beam is used, but an expanded parallel laser beam with an almost constant energy density. With this expanded jet, each drive module can be ignited regardless of its axial position.

13 shows in cross section a charge tube 12 with six drive modules, each with a pyrotechnic ignition device 39 ₅ . The circular segment-like inwardly projecting parts 43 of the pyrotechnic decoupling devices 39 ₅ are each rotated by 60 ° relative to one another, so that each segment 43 of the decoupling devices 39 _s fills a part of the total cross section of the ignition channel 14. A laser beam, which has approximately the diameter of the ignition channel 14, therefore detects all six segments 43 of the decoupling devices 39 ₅ . A simultaneous ignition of all drive modules 15 is thereby achieved.

An optical decoupling device can also be in the form of pyrotechnic decoupling devices 39--39 ₅ the fig. 8 to 12 can be formed, the part projecting into the ignition channel being designed as a mirror which is at approximately 45 ° to the longitudinal axis of the ignition channel and deflects a part of the laser beam to the outside.

The laser-initiated simultaneous ignition system can also be used to ignite explosive samples or ignition elements.

Claims

PATENT CLAIMS

_1st Laser-initiated simultaneous ignition system with at least one ignition charge (27) and / or an explosive (16) propulsion module (15),

characterized ,

that along the beam path of a laser beam (23, 23 ') for coupling out at least a part (25, 25') of the laser beam (23, 23 ') or light, a coupling-out device (18, 18', 30, 30 _l; 30 ₂ , 39 _x - 39 ₅ ) is arranged, which causes the ignition charge (27) or the explosive (16) of the drive module (15) to be ignited when the laser beam (23, 23 ') strikes.

2. Laser-initiated simultaneous ignition system according to claim 1, characterized in that each drive module (15) or each ignition charge (27) has an ignition channel (14) in which the decoupling _device (18, 18 ', 30, 30 _lf 30 ₂ , 39 ₁ -39 ₅ ) is arranged.

3. Laser-initiated simultaneous ignition system according to claim 2, characterized in that the drive modules (15) or ignition charges (27) are arranged such that the ignition channels (14) form a single straight and continuous channel for the laser beam (23,).

4. Laser-initiated simultaneous ignition system according to one of claims 1-3, characterized in that simultaneously from each decoupling device (18, 18 ', 39 _! -39 ₅ ) a part of the laser beam (23, 23') or light is coupled out.

5. Laser-initiated simultaneous ignition system according to one of claims 1-4, characterized in that the decoupling device (18, 18 ') is an optical element which forms part (25, 25') of the laser beam (23, 23 ') or - deflects light onto the ignition charge (27) or the explosive (16).

6. Laser-initiated simultaneous ignition system according to one of claims 1-4, characterized in that the decoupling device is a pyrotechnic element (30., 30 ₂ , 39. -39 ₅ ), on which at least part of the laser beam (23) strikes, whereby it is ignited and in turn ignites the explosive (16) of the respective drive module (15) or the ignition charge (27).

7. Laser-initiated simultaneous ignition system according to one of claims 2-6, characterized in that the optical or pyrotechnic coupling device (18, 18'30., 30 ₂ , 39.-39 ₅ ) each shadows only a part of the laser beam (23) , so that the remaining part of the laser beam (23) can pass through the respective ignition channel (14).

8. Laser-initiated simultaneous ignition system according to claim 6 or 7, characterized in that the pyrotechnic outcoupling device (30,30- ^ 30 ₂ ) protrudes annularly into the ignition channel (14) and only after lighting and partial burning the Laser beam falls on the coupling ring of the following drive module (30 ').

9. Laser-initiated simultaneous ignition system according to any one of claims 6-8, characterized in that the pyrotechnic decoupling arrangement (39 ^ ₃₉₎ projecting into the channel center part having (31- 45) so that all Auskoppelvorrichtungen are detected simultaneously by the laser beam can .

10. Laser-initiated simultaneous ignition system according to one of claims 6-9, characterized in that the pyrotechnic coupling device (39i-39 ₅ ) is an explosive-coated film.

11. Laser-initiated simultaneous ignition system according to one of claims 1-10, characterized in that the ignition channel (14) is circular.

12. Laser-initiated simultaneous ignition system according to one of claims 6-11, characterized in that the explosive of the film and / or the drive module is colored in such a way that it has a high degree of absorption in the region of the wavelength of the laser light.