EP3771881B1 - Pyrotechnic initiator for initiating an ignition tube and method for initiating an ignition tube - Google Patents

Description

The invention relates to a pyrotechnic initiator for initiating an ignition tube according to claim 1 and a method for initiating an ignition tube according to claim 7. The relevant prior art is described in US2980019A disclosed.

Ignition tubes are mainly used for pressure-based triggering of distance shooting or defusing devices, for the pyrotechnic generation of flashes of light in film and television production facilities and/or for the orderly transmission of an ignition pulse from one or more triggering devices to the explosive charges that are ultimately to be detonated (e.g. in the quarry for the extraction of gravel stones for road construction). An ignition tube usually consists of an explosive mixture, for example a mixture of octogen and aluminum.

The transmission of the ignition pulse in an ignition tube is based on a so-called shock tube effect. An explosive is finely distributed in a hose. Under these circumstances, the explosive is detonated in a directed manner, producing a flash of light within a surrounding plastic tube. An explosion triggered at one end of the ignition hose can be directed over any distance using this mechanism. The plastic tube, as a pure means of transport for transmitting the ignition pulse or flash of light, is generally not destroyed. Such ignition hoses are - depending on the type of triggering and the specific intended use - possibly closed at one end and firmly connected to a detonator at the other end.

Effecting an initial ignition of the explosive in the ignition tube is hereinafter referred to as initiating. The means by which this initiation is effected is hereinafter referred to as the initiator.

Ignition hoses are primarily used in blasting technology to fire a detonator cap (usually with a primary explosive, e.g. lead or silver azide) attached to the end. The ignition hose offers the advantage that an ignition pulse can be transmitted in a non-electrical manner and that this transmission is resistant to external influences (especially electrostatics and radio waves). This reduces undesirable early ignition.

Various ignition variants are known for ignition hoses to initiate the ignition pulse.

In a first ignition variant, a detonator - usually filled with primary explosive - is used, which generates a detonative shock pulse. The detonator is a closed metal capsule that is predominantly filled with a primary and secondary charge of various explosives. One capsule contains approximately 1,100 mg of explosive. The disadvantage of this variant is that a detonator used for initiation explodes when ignited due to the construction required, producing energetic fragments that are lethal at close range.

Alternatively, in a second ignition variant, a hose is triggered with a high-energy piezo spark. However, the piezo spark requires high voltages and amounts of energy. The high voltage can also have a lethal effect if, for example, a defect in the shielding leads to discharges onto the human body.

A third ignition variant uses primer caps that contain small amounts of primary explosives such as lead trinitroresocinate and tetrazine. These are ignited mechanically. Although these means can be purchased freely and can also be used by inexperienced users, they do not allow the ignition hose to be initiated from any distance. The user must always be at the end of the ignition hose with the triggering device and therefore relatively close to the explosion site, unless the ignition hose is particularly long, which then causes higher costs due to the use of materials.

The task is therefore to provide a device and a method with which an ignition hose can be initiated from practically any Distance, wired and in particular wireless, for example via an air interface (radio), can be carried out. In any case, the initiation should be able to be carried out without risk of injury for the personnel involved and the ignition hose should also be initiated safely so that misfires are practically impossible.

The task is solved on the device side with a pyrotechnic initiator for initiating an ignition tube with the features of claim 1 and on the method side with a method for initiating an ignition tube with the features of claim 7. The subclaims each contain expedient and/or advantageous embodiments and refinements.

On the device side, according to the invention, a pyrotechnic initiator is provided for initiating an ignition tube by means of an electrical trigger. This includes a sleeve that is open on one side and has a igniter inside. The igniter consists of a filament and a pyrotechnic set or several pyrotechnic sets surrounding the filament to generate a detonative shock pulse. The ignition hose can be coupled to the sleeve, which is open on one side, and an explosive present in the ignition hose can be initiated by the shock pulse.

The basic idea of the pyrotechnic initiator according to the invention is therefore to make an electrical triggering possible via the combination of a glow wire and a pyrotechnic set or several pyrotechnic sets. Typically, pyrotechnic set triggers are designed to trigger pyrotechnic effects (such as Bengal lights or black powder-based fuses). Similar to a match head, they produce a burning flame and hot sparks for a short time. Set triggers are traditionally igniters; they do not produce a detonative shock impulse.

According to the invention, however, the pyrotechnic active component is not formed from a typical slow-burning igniter material, as is otherwise the case with conventional igniter pills, so it does not burn slowly in the true sense. With such a conventional igniter, initiating an ignition hose is not even possible.

Instead, the invention provides that the pyrotechnic composition explodes quickly and thereby initiates the explosive in the ignition tube. The sleeve, which is open on one side, directs the explosion effect towards the ignition hose. In contrast to piezoelectric ignition mechanisms otherwise used, no dangerous electrical voltages are used according to the invention. However, the shock pulse causes the ignition hose to be initiated safely and effectively.

It is therefore an essential aspect of the basic idea according to the invention to use the principle of the set trigger to initiate the ignition tube and to design the initiator accordingly. However, in contrast to the known detonator, the initiator according to the invention is not an explosive detonator, since the impulse emanating from the object - as with a primer cap with a very small amount of explosive charge - is not sufficient to initiate a sensitive explosive test charge. Since the mixtures used in ignition tubes contain an explosive explosive and pyrophoric aluminum, ignition tubes are more susceptible and much easier to initiate than a commercially available explosive.

According to the invention, a splinter protection is provided for surrounding the sleeve for the sleeve, which is open on one side, with the splinter protection preventing the sleeve from being torn open to the side while the shock pulse is being generated and the release of splinters of the sleeve into the environment can be prevented.

This eliminates the risk of splinters being thrown around and ensures a high level of safety for the user, even during the otherwise critical preparation activities - from an occupational safety perspective.

In one embodiment, the splinter protection is designed as a flexible hose surrounding the sleeve, in particular a compressed air hose with thread inserts. Such an embodiment saves mass and reliably prevents the release of splinters.

Alternatively, the splinter protection can be designed as a rigid cylinder surrounding the sleeve, in particular as a metal or plastic cylinder.

In one embodiment, the sleeve, which is open on one side, has a sleeve base in the form of a plug that can be inserted into the sleeve, the plug having through openings for electrical feeds for the glow wire. The at least one pyrotechnic set can thereby be plugged together by assembling the plug with the sleeve.

According to the invention, an adapter is provided for the centered insertion of the ignition hose into the sleeve, the end of the ignition hose being positioned directly in front of the igniter pellet. The adapter ensures optimal coordination between the diameter of the ignition hose and the diameter of the sleeve, optimal positioning of the ignition hose on the sleeve and optimal transmission of the explosion effect to the end of the ignition hose.

The initiator according to the invention is further characterized in that the adapter, the ignition hose and the sleeve form an arrangement that can be firmly fixed and/or sealed together using a pliers tool.

The pyrotechnic set is designed for a quick explosion. This means, above all, that the pyrotechnic set of the igniter is designed to generate a significant explosion pressure of more than 10 bar in conjunction with a shower of sparks directed at the end of the ignition hose.

On the method side, to initiate the ignition tube, it is provided according to the invention that a shock pulse is applied to an open end of the ignition tube via a igniter made of a glow wire and a pyrotechnic set or several pyrotechnic sets and an explosive present in the ignition tube is initiated by the effect of the shock pulse, and a detonation occurs.

The shock pulse expediently acts as a directed explosion pulse on the end of the ignition tube, for which purpose the end of the ignition tube and the ignition pill are located within a surrounding sleeve that determines the direction of explosion.

When the process is carried out, the explosion pressure of the shock pulse is expediently greater than 10 bar.

The pyrotechnic initiator according to the invention and the method according to the invention will be explained below using exemplary embodiments. These are used for clarification Figures 1 and 2 . The same reference numerals are used for identical and identically acting parts.

• Fig. 1 den pyrotechnischen Initiator in seinem prinzipiellen Aufbau,
• Fig. 2 eine beispielhafte Gestaltung des pyrotechnischen Initiators.

It shows:

• Fig. 1 the pyrotechnic initiator in its basic structure,
• Fig. 2 an exemplary design of the pyrotechnic initiator.

Fig. 1 shows an exemplary structure of the pyrotechnic initiator. The figure shows an ignition hose 1 which is coupled to a pyrotechnic initiator. The pyrotechnic initiator contains a sleeve 2. This is open on one side in the direction of the ignition hose. The sleeve can, for example, consist of a metallic material, but also of plastic. The sleeve 2 contains a igniter 3 inside. The igniter 3 consists of a filament 5 arranged between two electrical poles 4 and a pyrotechnic set or sets of pyrotechnics 6 which surrounds the electrical poles and the filament.

The pyrotechnic set or the several pyrotechnic sets can be detonated via the filament. Electrical supply lines 7 are provided to supply electricity to the glow wire. When the pyrotechnic device explodes, the explosion acts predominantly in the direction of the ignition hose and thereby initiates an explosive 8 within the ignition hose 1, the detonation of which then continues through the ignition hose to the respective target location, provided that the hose is used for explosive purposes.

The explosion of the pyrotechnic charge or the pyrotechnic charges 6 also usually causes the sleeve 2 to burst. The fragments and splinters resulting from the bursting are thrown through the sleeve Surrounding splinter protection 9 is caught and prevented from being released into the environment. What is advantageous here is a flexible design of the splinter protection, in particular in the form of a hose section that is reinforced internally with a thread braid.

Of course, it is also possible to have a rigid design of the splinter protection in the form of a non-metallic or metallic casing, for example in the form of a plastic or steel cylinder.

In the schematic structure shown here, the bottom of the sleeve 2 consists of a plug 10 that can be inserted into the sleeve, through which the electrical supply lines 7 are passed via through openings 10a. The entire arrangement of plug 10 and igniter 3 can be inserted as a whole into the sleeve.

An adapter 11 is also provided for precise and centered positioning of the ignition hose 1 in the sleeve 2. This is plugged onto the ignition hose 1 and then inserted together with the ignition hose into the sleeve 2, whereby the end of the ignition hose is placed directly on the ignition pill 3 and thus comes into contact with the pyrotechnic composition. The adapter can be both rigid and flexible and made of different materials, for example plastic or metal. With a flexible design of the adapter, it is designed as a hose section. Finally, this entire unit, i.e. the sleeve 2 with the adapter 11, is crimped with pliers and is ready for use. Usually the igniter 6 is also crimped with the plug 10 and the metal sleeve 2.

The splinter protection 9 is then pushed onto the entire arrangement consisting of the adapter with ignition hose, sleeve and plug. If necessary, fixation is carried out, for example, using a sufficiently strong adhesive tape, in particular a fabric adhesive tape.

Fig. 2 shows an example of the use of the pyrotechnic initiator. The initiator here consists of the igniter 3 and the sleeve 2 surrounding this igniter. The adapter 11 is inserted into the sleeve 2 surrounding the igniter Ignition hose 1 inserted. The ignition hose 1 protrudes a certain distance into the area of the igniter 3 via a projection 13 and is thereby centered in its position. Slipping of the ignition hose is prevented by a corrugation 12 on the sleeve 2.

The splinter protection 9 in the form of a flexible hose section is pushed directly onto the sleeve 2 and the adapter 11. This provides flexible splinter protection. The electrical supply lines 7 open into the igniter 6.

The ignition hose is initiated using the device described here as follows:
The igniter pill is located in the sleeve, which is open at the front, as described. This contains two poles between which the glow wire is attached. Explosive mixtures, for example of zirconium and potassium perchlorate, are arranged around the filament as a pyrotechnic set. If necessary, the filament is first surrounded with a first heat-sensitive pyrotechnic set, which reacts more quickly to heat, before the actual active mass follows as a second pyrotechnic set. The net explosive mass for the entire initiator is up to 100 mg.

The supply lines to the poles are led out of the sleeve to the rear through a stopper or plug with two holes. The supply lines can be extended to almost any length and can be connected in particular to radio ignition devices. This makes it possible to trigger from a greater and therefore safer distance.

The adapter is inserted into the open end of the sleeve as described, into which the open ignition hose is inserted into the sleeve until immediately in front of the igniter. The hose is then crimped tight with pliers. The adapter can be designed flexibly as a hose adapter.

If a defined current is applied to the poles through the cable, the wire glows and causes the pyrotechnic device to explode. This creates a pressure pulse with a strength of more than 10 bar and a shower of sparks. Through The impact of these triggers the explosive in the ignition tube and stimulates the ignition tube to transmit the detonative explosive impulse. The explosive pulse can now be forwarded through the ignition hose to the actual location of the intended effect, ie in particular to the intended explosive device, if an explosive application is carried out.

Since the ignition hose in this case is inserted centered in the metal sleeve using the adapter and is fixed and sealed almost watertight (for example with a crimping pliers), the pressure build-up in the sleeve is significantly increased and can have a concentrated effect on the end of the ignition hose.

The pressure and sparks created in the sleeve can initially only escape into the open ignition hose; There it releases the hose or the explosive deposits there. This arrangement promotes safe initiation, otherwise the tube will not be initiated correctly.

The initiator sleeve may tear open laterally as a result of the rapid explosion, and splinters may occasionally form. However, due to the special design of the igniter and the splinter protection pushed over the casing, unlike a normal detonator, high-energy casing fragments are not released in the immediate vicinity, but are intercepted. The splinter protection pulled over the sleeve usually consists of a standard compressed air hose with thread inserts. Rigid steel or plastic cylinders can also be used as splinter protection, but they are comparatively heavy.

Due to its specific structure, the set trigger here can, on the one hand, initiate an ignition hose. On the other hand, it only requires an extremely small safety area. Due to its design and splinter protection, the present initiator could even be held in the hand in a completely safe manner when triggered. Lethal or even injurious splinters are not produced when used as intended.

According to explosives regulations, conventional detonators may only be handled by trained specialists.

These require official approval. This also applies to transport, for example for truck drivers. The transfer of detonators, especially in the EU, from one country to another country also requires appropriate approval from all states.

However, due to the construction method used here, handling the present initiator is legally possible and permissible by people aged 18 and over without specialist knowledge. Shipping can therefore take place with a normal parcel service and even without a special shipment permit. In contrast to conventional detonators, which can also be used to initiate a detonator tube, this allows cost-effective transport.

In comparison to piezo trigger elements, which can be used multiple times but are comparatively expensive, the initiator described here can only be used once. However, it is significantly cheaper to produce and also enables simple and safe triggering from a distance with completely harmless operating voltages. In principle, the initiator described here can be combined with all voltage-supplying power sources and connected to them. These can be controlled in any way, in particular wirelessly, so that there is the possibility of simultaneous remote triggering of several ignition hoses, which is otherwise only possible with ignition variant 1 and not with variants 2 and 3.

The initiator and the process carried out with it were explained as examples, and further configurations are possible within the scope of professional action. Further embodiments also emerge from the subclaims.

Reference symbol list

1

ignition hose

2

sleeve

3

igniter pill

4

Electric poles

5

filament

6

Pyrotechnic set

7

Feed lines

8th

Explosive

9

Splinter protection

10

Plug

10a

Through opening

11

adapter

12

corrugation

13

Got over

Claims (9)

1. A pyrotechnic initiator for initiating an ignition tube (1) by means of electrical triggering, comprising

   a sleeve (2) that is open on one side and has an ignition pill (3) that is located therein and is made of a glow wire (5) and at least one pyrotechnic set (6) surrounding the glow wire for generating a shock pulse initiating the end of the ignition tube,

   wherein the ignition tube (1) can be coupled to the sleeve (2), which is open at one end, and an explosive (8) present in the ignition tube can be initiated by the shock pulse,

   characterized in that

   a splinter guard (9) is provided for the sleeve (2), which is open on one side, for surrounding the sleeve, wherein a tearing open of the sleeve (2) during the generation of the shock pulse can be contained by the splinter guard (9) and the release of splinters into the environment can be prevented, wherein an adapter (11) is provided for the centered insertion of the ignition tube (1) into the sleeve (2), wherein the end of the ignition tube can be positioned directly in contact with the ignition pill (3), wherein the adapter (11), the ignition tube (1) and the sleeve (2) form an assembly which can be firmly fixed and/or sealed with respect to each other by means of a pliers tool.
2. The pyrotechnic initiator according to claim 1,
   characterized in that
   the splinter guard (9) is formed as a flexible tube surrounding the sleeve (2).
3. The pyrotechnic initiator according to claim 1 or 2,
   characterized in that
   the splinter guard (9) is formed as a rigid cylinder, in particular a metal or plastic cylinder, surrounding the sleeve (2).
4. The pyrotechnic initiator according to any one of the preceding claims,
   characterized in that
   the sleeve (2), which is open on one side, has a sleeve base in the form of a plug (10) which can be plugged into the sleeve, wherein the plug (10) has feed-through openings (10a) for electrical leads (7) for the glow wire (5).
5. The pyrotechnic initiator according to any one of the preceding claims,
   characterized in that
   the pyrotechnic set (6) of the ignition pill (3) is designed to generate an explosion pressure of more than 10 bar in conjunction with a shower of sparks directed towards the end of the ignition tube.
6. The pyrotechnic initiator according to any one of the preceding claims,
   characterized in that
   the pyrotechnic initiator has a net explosive mass of at most 100 mg.
7. A method for initiating an ignition tube by means of a pyrotechnic initiator according to any one of claims 1 to 6,
   characterized in that
   a shock pulse from a glow wire (5) and a pyrotechnic set (6) is caused to act on an open end of the ignition tube (1) via an ignition pill (3) and an explosive present in the ignition tube is initiated by the effect of the shock pulse.
8. The method according to claim 7,
   characterized in that
   the shock pulse acts as a directed pulse on the end of the ignition tube (1), wherein for this purpose, the end of the ignition tube (1) and the ignition pill (3) are located within the surrounding sleeve (2) which determines the direction of explosion.
9. The method according to any one of claims 7 or 8,
   characterized in that
   the explosion pressure of the shock pulse acting on the open end of the ignition tube (1) is greater than 10 bar.

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