EP2431704B1 - Method for opening, defusing and/or burning out bombs or munitions containing explosives - Google Patents

Description

The invention relates to a method for opening, defusing and / or burning explosive-containing bombs or projectiles and a use. It can also be a variety of types on funded and unburned ammunition.

When finding munitions, and in particular bombs of any kind or even large-caliber projectiles, it is often necessary to render them harmless on site, since a transport to a suitable place where safe handling of such Fundmunitiön can take place, for safety reasons not always can be carried out.

Frequently, the fundmunition is heavily corroded as a result of corrosion of the metal housing and the attached thereto Ignition devices are also in a desolate condition, so that they can not be dismantled from a bomb then safely.

Attempts have therefore been made to open the metal housing of bombs or projectiles at the site. For this purpose, the water jet cutting was used, which actually seems suitable because no high temperatures occur. However, it has been found that the time required, in particular in the case of the relatively thick metal housings of bombs, is too great and it can not be avoided to introduce vibrations or oscillations into the bomb or a projectile which can cause a triggering of the ignition device.

Besides, it is off DE 603 18 298 T2 known to perform a destruction with an explosive charge and a projectile. Again, there is a risk of impairment of the environment, buildings and the life or health of people in the area. This problem also occurs in other known technical solutions in which a projectile is shot at such an explosive device or mounted and ignited a charge leading to the explosion.

In US Pat. No. 6,559,413 B1 , which forms a starting point for claim 1, a method for laser treatment of explosive objects is known. In this case, a laser beam to be directed to a surface area of an explosive mass to melt them and evaporate.

It is therefore an object of the invention to provide ways by which defuses bombs or projectiles or can be opened, and thereby the risk of explosion hazard is reduced.

According to the invention, this object is achieved by a method having the features of claim 1. Advantageous embodiments and further developments of Invention can be realized with features designated in subordinate claims.

In the method according to the invention for opening, defusing and / or burning explosive-containing bombs or projectiles, at least one plasma torch is used when opening the metal housing of a bomb or a projectile.

It has surprisingly been found that, although temperatures in the plasma jet of a plasma torch can prevail at temperatures of up to 30,000 ° C., an opening of the metal housing can take place without the contained explosive being able to develop its explosive effect in a dangerous form. Just these high temperatures make it possible to form a sufficiently large opening in the metal housing in a very short time, which has a free cross-section, in which a pressure compensation, which occurs by a chemical reaction of the explosive, can be achieved. The chemical reaction can not be explosive, but much slower and the explosive can be flamed or simply burned / burned out.

For this reason, a plasma torch can also be used in bombs or projectiles, in which only explosives remain in the metal housing.

Prior to performing the procedure, a thickness determination of the housing of a bomb or bullet should be made. This can be done on the basis of ammunition data sheets. In this case, the respective bomb or a projectile or any other type of ammunition is taken, what can also be done by video technology and then the corresponding data of the type determined in this way can be taken from the respective ammunition data sheet. A thickness determination can also be made by ultrasonic thickness measurement. With the determined thickness then the one or more plasma torches can be operated in a suitable manner. This relates to the operating parameters and it may also be the size and position of trainees openings to be chosen accordingly.

It is possible to use one or more plasma torches with a circular cutting device. This can be remote controlled. One or more plasma torches are arranged eccentrically on the circle cutting device and can be moved along a circular path during cutting. Several plasma torches can be arranged at equal angular distances from each other. For two plasma torches it can be 180 °.

In the invention, the procedure should be such that an opening is formed in the metal housing, which has at least one free open cross section of 100 mm ² , advantageously at least 100 cm ² , to allow the desired pressure equalization. This should be achieved in a time <10 s, preferably <6 s. Of course, an opening with a larger free cross section can be formed in a correspondingly short time in the metal housing. The plasma torch is moved accordingly. It can be moved translationally and / or pivoted, so that the position is hit by the plasma jet on the metal housing is changed. However, it should be done so that a completely through the wall of the metal housing opening is trained.

One or more apertures to be formed may be formed with a size that may be selected as an explosive depending on the size of the entire envelope surface of a bomb or projectile. Here, a size in the range of 1/4 to 1/1000, preferably ½ to 1/100 of the lateral surface can be cut out.

Before the actual opening of the metal housing with a cutout, a discharge opening for a possible pressure equalization through the housing can be formed.

Cut-out housing parts can be removed or otherwise removed with suitable manipulators. In this case, magnets or elements working with negative pressure can be used.

In the invention, it is also possible to produce a plurality of spaced-apart openings successively with a plasma torch, which are arranged distributed over the circumference.

For safety reasons, a plasma torch can be guided by a robot and preferably be remotely controlled. In this case, it is convenient to use a video camera for manual remote control. Plasma torches and / or robots can be controlled.

In carrying out the method according to the invention, a shield can be used around or over the bomb or a projectile in order to reduce the risk of an undesired explosion. For this purpose can thick-walled conical steel body are used, which can be placed next to and / or on each other.

Different plasma torches, in particular suitable for cutting, can be used in the invention. These can also be those in which an electrode is arranged directly on the plasma burner and the workpiece, here in the specific case that is a bomb or a projectile is electrically connected so that it forms the second electrode for plasma formation.

However, since the metal housings are often severely corroded and for safety reasons plasma torch with indirect operation or designed for cutting electrically non-conductive workpieces plasma torch with an arranged between a nozzle and a bomb or a projectile, outside the nozzle of the plasma torch, can be inserted into the plasma jet Additional electrode, to be preferred. A trained for cutting electrically non-conductive workpieces plasma torch is in DE 10 2005 039 070 A1 described. Such a trained plasma torch can be used in the invention.

In an indirectly operated and a plasma torch, which is suitable for cutting non-electrically conductive workpieces, no direct electrical connection to a metal housing of a bomb or a projectile is required, which increases the safety and also the reliability (because of possible corrosion on the metal housing).

Plasma is a thermally highly heated electrically conductive gas, which consists of positive and negative ions, electrons and excited and neutral atoms and molecules.

As plasma gas are different gases, eg. As the monatomic argon and / or the diatomic gases hydrogen, nitrogen, oxygen or air used. These gases ionize and dissociate through the energy of the plasma arc. The plasma jet can be greatly influenced in its parameters by the design of the nozzle and electrode. These parameters of the plasma jet are e.g. the beam diameter, the temperature, energy density and the flow velocity of the gas. This allows a good adaptation to be achieved in the method according to the invention, as may be required, for example, in the different bombs or projectiles. Especially with bombs, the different types and the different metal housing can be considered with their thicknesses and materials.

Plasma torches in which a secondary gas is used in addition to the plasma gas can be used in the invention. In this case, the secondary gas can be enveloped by a correspondingly designed nozzle design of a plasma torch surrounding the plasma jet, in the direction of the bomb or projectile surface, for example as a ring beam.

Preferably, a plasma cutting torch is used as a plasma torch. The electrical current density of the plasma arc, which is constricted by means of the nozzle of the plasma torch, should be at least 30 A / mm ² , preferably at least 50 A / mm ² , in the nozzle bore.

As plasma and / or secondary gas, air, nitrogen, oxygen or a gas mixture formed with these gases can be used.

The plasma burner should be operated with an electrical cutting current of at least 200 A and / or maintain a cutting speed of at least 3 m / min with a metal casing thickness of a bomb or bullet of 12 mm. Thus, an opening with a diameter of 10 cm * 10 cm can be cut in about 8 s.

When using a circular cutting device in which a plasma torch is rotated about an axis of rotation to which it is spaced, an opening with a diameter of about 13 cm can be cut through the metal housing.

If the plasma burner is operated with a larger electric current, for example 300 A, the cutting speed can be increased to more than 4 m / min with a metal housing thickness of 12 mm. The time for cutting the opening can be shortened to approx. 6 s. When using two plasma torches, the required time can be reduced to 3 s. Two plasma torches can be arranged offset by 180 ° to each other, while also being rotated about an axis of rotation disposed between the plasma torches. Two or more than two plasma torches can also be moved independently with suitable manipulators and then an opening or so it can be cut out several openings at the same time. As a result, one or more openings with correspondingly larger free cross-section in the metal housing at the same time as when using a plasma torch are formed.

After the formation of an opening in the housing, there is free access to atmospheric oxygen, and at sufficient temperature, the contained explosive can easily burn. Here, the short time required for opening and the small thermal conductivity of the explosives has an effect. The critical temperatures for a detonation are not reached for the explosive and the ignition device. The temperature increases by a maximum of 30 K.

After one or more sufficiently large opening (s) have been formed in the housing and until then the contained explosive does not burn, it can be ignited with a plasma torch and then burned. The burning takes place in these cases, as is already known when burning explosives in open channels. If an ignition device is still present when the explosive is burned, its ignition takes place at a time when there is a sufficiently large opening in the housing, so that the effect is considerably reduced due to missing or greatly reduced damming and the residual effect is negligible. An uncontrolled detonation can be avoided.

The invention can be carried out directly at a locality.

Below, the invention for the opening, defusing and / or burnout of bombs or projectiles will be explained in more detail by way of example.

Figur 1

ein Beispiel zum direkten Plasmaschneiden;

Figur 2

ein Beispiel zum indirekten Plasmascheiden;

Figur 3

ein Beispiel mit einem Plasmabrenner, der eine außerhalb der Düse eine in den Plasmastrahl einführbaren Zusatzelektrode;

Figur 4

ein Beispiel, bei dem ein Plasmabrenner um eine Rotationsachse beim Schneiden gedreht wird und

Figur 5

ein Beispiel bei dem zwei Plasmabrenner gedreht werden.

Showing:

FIG. 1

an example of direct plasma cutting;

FIG. 2

an example of indirect plasma separation;

FIG. 3

an example with a plasma torch, the one outside the nozzle an insertable into the plasma jet additional electrode;

FIG. 4

an example in which a plasma torch is rotated about an axis of rotation when cutting and

FIG. 5

an example in which two plasma torches are rotated.

The figure shows an arrangement for direct plasma cutting on a bomb 4. The plasma torch 2 is connected via the electrical connection lines 5.1 and 5.2 to an electrical power source 1. The bomb 4 is connected to the electrical power source 1 via the electrical connection line 5.3. The gas supply takes place from the gas supply 6 to the plasma burner 2 via the gas lines 5.4 and 5.5.

The plasma torch 2 has a burner head with a beam generating system. At the burner head, an electrode 2.1, a nozzle 2.2, a gas supply 2.3 and a burner body are present. In the burner body, the feeds of the media (eg gas, coolant, electric power) are realized and the gun system available. In addition, a cap 2.4, which is designed for the supply of a secondary medium, for example secondary gas, can be present around the nozzle 2.2 of the plasma burner 2.

The electrode 2.1 in the plasma torch 2 is a non-consumable electrode consisting essentially of a high temperature resistant material, e.g. Tungsten, zirconium or hafnium is formed, thereby achieving a long life. The nozzle 2.2 is made of copper and constricts the formed plasma jet 3 a.

The electric current flow for cutting takes place from the electric current source 1 to the plasma burner 2, via the plasma jet 3 to the metal housing of the bomb 4 and from there back to the electric current source 1. For cutting, a pilot arc between the electrode connected as cathode 2.1 and the nozzle 2.2 is first ignited with a small electrical current in the range 10 A to 30 A and thereby burns with a correspondingly low power. In this case, a high electrical voltage is selected.

The low-energy pilot arc causes a partial ionization between the plasma torch 2 and the metal housing of the bomb 4 and thus prepares the formation of the cutting arc. The cutting arc is then formed between the electrode 2.1 and the metal housing of the bomb 4 with a significantly higher electrical current of at least 200 A. The metal housing can thus be cut at a high feed rate of 3 m / min and formed in a time of about 6 s a sufficiently large opening with free cross section, which prevents possible ignition and exploding of the contained explosive by the high heat, so that the Explosives can be burned out without exploding.

The FIG. 2 shows an arrangement for indirect plasma cutting. It flows in contrast to the example after FIG. 1 the electric current not via the metal housing of the bomb 4, but from the nozzle 2.2 to the electric power source 1 back. At the nozzle 2.2, a second electrode is then present or the nozzle 2.2 forms the second electrode. In this example, advantageously no electrical connection to the bomb 4 is required, which may be problematic due to corrosion of the metal housing. Incidentally, in this example, analogously to the example FIG. 1 to be worked. The ionization takes place between electrode 2.1 and nozzle 2.2.

In FIG. 3 an example of plasma cutting is shown in which outside of the nozzle 2.2 of the plasma torch 2 in the plasma jet 3, an additional electrode 7, for example a wire, which tracked by means of the wire drum 8, can be introduced. The electrical connection of the additional electrode 7 via the Stromkontaktdüse 9 to the electric power source 1. The basic structure and the function are in DE 10 2005 039 070 A1 described. Again, no electrical connection to the bomb 4 is required to work according to the invention.

In FIG. 4 an arrangement with a guided plasma torch 2 is shown. The plasma torch 2 is held with a holder 10.1 at a distance from the axis of rotation 10. To form a circular opening with a radius which corresponds approximately to the distance of the plasma torch 2 with its plasma jet 3 to the axis of rotation 10, the plasma torch 2 is rotated by 360 ° about the axis of rotation. The lines 5 for electricity, gas and coolant to the plasma torch 2 are flexible.

In FIG. 5 an example is shown with two plasma torches 2, which are arranged together in the holder 10.1 each at a distance from the axis of rotation 10 and are rotated to cut an opening in the metal housing of the bomb 4 about the axis of rotation. With this arrangement, a rotation of 180 ° is sufficient for the cutout. The required time can be shortened.

LIST OF REFERENCE NUMBERS

1

electrical power source

2

plasma torch

2.1

electrode

2.2

jet

2.3

Plasma gas supply

2.4

Secondary gas cap

2.5

Secondary gas supply

3

plasma jet

4

bomb

5

Connection lines u. hoses

5.1

electrical connection electrical power source to the electrode

5.2

electrical connection electrical power source to nozzle for electrical pilot or cutting current

5.3

electrical connection electrical power source to the metal housing

5.4

Head of plasma gas

5.5

Line for secondary gas

6

gas supply

7

additional electrode

8th

wire drum

9

current contact nozzle

10

axis of rotation

10.1

bracket

Claims (9)

1. A method for opening, defusing and/or burning-out explosives-containing bombs or projectiles, characterised in that at least one plasma burner (2) is used for opening the metal casing of a bomb (4) or a projectile.
2. A method according to Claim 1, characterised in that an opening is formed in the metal casing, which opening has at least a free open cross-section of 100 mm².
3. A method according to Claim 2, characterised in that the opening is formed in a timeframe of < 10 s.
4. A method according to one of the preceding claims, characterised in that a plurality of openings arranged spaced-apart from each other are formed in succession with a plasma burner (2) or simultaneously with a plurality of plasma burners (2), which are arranged distributed over the periphery.
5. A method according to one of the preceding claims, characterised in that plasma burners (2) with a direct, with an indirect operating mode, or a plasma burner (2) formed for cutting electrically non-conductive workpieces with an additional electrode (7) which is arranged between a nozzle (2.2) and a bomb (4) or a projectile, outside the nozzle (2.2) of the plasma burner (2), and which can be introduced into the plasma jet (3) is/are used.
6. A method according to one of the preceding claims, characterised in that one or more plasma burner(s) (2) arranged at a distance from a rotation spindle (10) to form an opening are turned about the rotation spindle (10).
7. A method according to one of the preceding claims, characterised in that the plasma burner (2) used is guided and remotely controlled with a robot.
8. A method according to one of the preceding claims, characterised in that a video camera is used and the robot and/or the plasma burner (2) is manually remotely controlled.
9. A method according to one of the preceding claims, characterised in that the type of a bomb (4) or a projectile and/or the thickness of the casing is/are determined prior to using a plasma burner.

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