Propellant charge that can be ignited by means of microwaves and method for igniting such a propellant charge

Abstract

The invention relates to a propellant charge (100) for a barrelled weapon (200), comprising a plurality of propellant charge grains (10), wherein a thin-film resonator (16) is applied to at least some of the propellant charge grains (10), said resonator surrounding the respective propellant charge grain (10) and having one or more spark gaps (18). The invention further relates to a method for igniting a propellant charge (100).

Description

[0001] Applicant:

[0002] Rheinmetall Waffe Munition GmbH Heinrich-Ehrhardt-Straße 2 29345 Südheide

[0003] 30800060WG 20.08.2025

[0004] ELL

[0005] Title: Microwave-ignitable propellant charge and

[0006] Method for igniting such a propellant charge

[0007] Description

[0008] The invention relates to a propellant charge with features of the preamble of claim 1. The invention further relates to an ignition arrangement and a cannon with the features of the dependent claims. Finally, the invention relates to a method for igniting a propellant charge for a cannon with the features of a further dependent claim.

[0009] Propellant charges and methods for igniting them are known from the prior art. For example, in the ignition of propellant charges in cannons, a mechanical initiation (impact triggering) is known, in which a firing pin on the weapon side strikes a primer (impact-sensitive igniting compound) at the rear end of the propellant charge, causing the igniting compound of the primer to react (classic primer-based ignition solution). The resulting flame ignites the main propellant charge. Since ignition occurs at the rear end of the propellant charge, this leads to spatially and temporally uneven ignition and complete ignition of the propellant charge, especially when the charge chamber of a cannon is only partially filled. This can cause pressure waves with elevated peak pressures to form in the charge chamber.

[0010] Furthermore, concepts using lasers and microwaves are known for igniting propellant charges, which heat a propellant charge in a targeted but macroscopic manner until the ignition temperature of an ignition charge or the propellant charge itself is reached.

[0011] An ignition system for a propellant charge that utilizes microwaves is known from US 10,859,358 Bl. In this system, an electromagnetic pulse is generated by means of a high-frequency transmitter, the energy of which is received by a high-frequency igniter located on the propellant charge and converted into heat. This heat ignites an initial charge, which in turn ignites a main propellant charge.

[0012] Another device for igniting propellant charges is known from RU 2 348 004 C2. In this device, propellant charges containing metal filaments are exposed to electromagnetic radiation. As a result of the electromagnetic radiation, the metal filaments heat up, and the propellant powder adjacent to the metal filaments ignites accordingly when the ignition temperature is reached. A problem with these microwave ignition methods is that, due to the macroscopic heating of the propellant charge, the temperature on the surface of the propellant grains rises relatively slowly. If a charge chamber of a barrel weapon containing the propellant charge is exposed to a microwave field, which heats the metal filaments and, if applicable, the propellant powder, the propellant charge is ignited more quickly.If the propellant charge itself is also heated by microwave heating according to the oven principle, the temperature of a heated element will rise (complex and subject to tolerances) until the ignition temperature of the corresponding or a nearby propellant particle is reached by convection, conduction, and radiation. Due to a variation in the influencing factors of the heat balance of elements within the charge chamber, modules of a propellant charge are ignited with a time offset, which can lead to undesirable pressure pulsations.

[0013] The invention is based on the objective of enabling rapid and efficient ignition of a propellant charge. It is desirable to minimize pressure pulsations.

[0014] The invention solves this problem by means of a propellant charge having the features of claim 1.

[0015] The propellant charge is designed and / or intended for a tube weapon. The propellant charge is designed as a microwave-ignitable or microwave-ignited propellant charge.

[0016] The propellant charge comprises a multitude of propellant grains. These together form the propellant charge or a propellant charge module. At least some of the propellant grains each have a thin-film resonator (electrically conductive) applied to them, which surrounds the respective propellant grain (equipped with a thin-film resonator) and has one or more (microwave-sensitive) spark gaps.

[0017] The proposed propellant charge enables rapid and efficient ignition using microwaves. When the propellant charge is exposed to a microwave field, a voltage is induced in the thin-film resonators (electrically conductive layers) that are applied to at least some of the propellant grains. This voltage causes sparks to jump across the (defined or arbitrary) spark gaps when the local breakdown voltage is reached, thus igniting the charge by spark discharge.

[0018] In contrast to the US 10,859,358 Bl and the RU 2 348 004 C2 described above, which heat metal filaments to ignite the propellant charge (according to the furnace principle), the propellant charge proposed here uses a spark discharge at spark gaps specifically designed for this purpose on the thin-film resonators of the propellant grains. This ignition occurs comparatively quickly because the temperature of the ignition spark, upon arcing, is immediately several thousand Kelvin above the ignition temperature of the propellant grain or any ignition mixture (described below) applied to the propellant grain. While, in furnace-like heating, the metal filaments are heated along a saturation curve according to their heat balance, the ignition temperature is present immediately in the spark-arrest ignition proposed here.Furthermore, spark ignition is insensitive to manufacturing tolerances, as a complex heat balance is not required.

[0019] In principle, propellant granules can have various grain geometries and / or compositions (e.g., single-, double-, or triple-base formulations). In one possible design, propellant granules can, for example, extend along a central longitudinal axis and have a cuboid or cylindrical shape, e.g., with a circular, elliptical, or n-sided cross-section (preferably n > 3 and n < 12). Regardless of this, the propellant granules can consist at least partially of nitrocellulose (guncotton) and optionally contain additives such as blasting oils, e.g., nitroglycerin (for higher energy), crystalline energy carriers, stabilizers, and / or other additives.

[0020] The propellant granules can optionally each have several channels, extending, for example, parallel to the central longitudinal axis, which penetrate the propellant granules. Alternatively or additionally, the propellant granules can each have surface grooves or special coatings. These measures aim to achieve progressive combustion, in which the combustion surface and thus gas production increases as the propellant granule burns.

[0021] Within the framework of a preferred design, the

[0022] Thin-film resonators each as at least partially made of

[0023] A metal (electrically conductive) foil can be formed with a structured pattern. This allows for the simple creation of spark gaps. The structure can consist of multiple structuring elements. These elements together form the structure. The structuring elements can be formed as raised areas or depressions on the foil.

[0024] Advantageously, the structuring can be designed as a perforation. A perforation can be introduced into a film relatively easily, e.g., by cutting or punching. The perforation is preferably distributed over the entire thin-film resonator (film), and in particular uniformly. The perforation has several or a multitude of perforation elements, wherein each perforation element (passage or slot, su) can form a spark gap.

[0025] The structuring, for example in the form of perforations, represents a resonant (microwave-sensitive) structure. A resonant structure generates field peaks or areas of high EM field through an electromagnetic field (EM field), so that a corresponding voltage potential is formed and the breakdown field strength or breakdown voltage is exceeded, resulting in the formation of a plasma or flashover through ionization.

[0026] In principle, resonant structures can be divided into basic shapes (e.g., triangle, rectangle, square, dipole, circle, annulus, ellipse) and derived shapes. Derived shapes can be structures in which the respective basic shape is repeated once or several times.

[0027] Specifically, the perforation can be either a punched perforation or a slotted perforation. A punched perforation can have several or a multitude of circular, elliptical, or n-sided openings. The openings can completely penetrate the film along its thickness direction. The openings can be arranged in a defined pattern, e.g., in several columns and rows. A slotted perforation can have several or a multitude of slots. The slots can each extend along a longitudinal direction and be oriented parallel to each other. The longitudinal direction of the slots can optionally be oriented parallel to the central longitudinal axis along which the propellant grains extend.

[0028] Alternatively, the thin-film resonators can each be designed as a coating containing (geometrically defined or undefined) metallic particles. Spark gaps can also be formed in a structurally simple manner using this method. A spark gap can be formed between each pair of adjacent metal particles. The metal particles can be metal grains, metal flakes, or a mixture thereof. The metal particles can be embedded in a matrix material and attached to the respective propellant grain via this matrix.

[0029] In principle, a combination of propellant granules with a structured metallic foil as a thin-film resonator and propellant granules with a particle-coated thin-film resonator is also conceivable. This also promotes spark discharge at multiple points within the propellant charge. Thus, some of the propellant granules can be equipped with a foil as a thin-film resonator, and another portion can be equipped with a particle-coated thin-film resonator. Optionally, a third portion of propellant granules can be present that are free of a thin-film resonator (non-microwave-sensitive propellant granules).

[0030] In a preferred embodiment, a pyrotechnic ignition mixture can be arranged as an intermediate layer between the propellant pellet and the thin-film resonator. The ignition mixture can facilitate the ignition of the propellant pellet, for example, by capturing any spark discharge at the spark gap and allowing the propellant pellet to be ignited over a large area by means of the ignition mixture. This contributes to a more uniform ignition.

[0031] Advantageously, a thin-film resonator can be applied to the majority of the propellant grains (more than 50%) or to all of them. This allows for targeted control of the ignition of the propellant grains. If only some or most (but not all) of the propellant grains are equipped with a thin-film resonator (prepared propellant grains), these grains serve as ignition points for other, non-microwave-sensitive propellant grains (propellant grains without a thin-film resonator). This also allows for ignition of the propellant charge at multiple points. If all propellant grains are equipped with a thin-film resonator, ignition of the propellant charge occurs at a particularly large number of points with the greatest possible temporal overlap.

[0032] The propellant granules can be advantageously contained in one or more containers. In other words, the propellant charge can comprise one or more propellant modules, each containing several or a multitude of propellant granules. This facilitates easy handling of the propellant charge, as the correct quantity of propellant granules can be placed in the container and protected from environmental influences. The container can be a bag or a tube-shaped receptacle, e.g., made of combustible casing material (CBH). The container is preferably designed and / or configured to be inserted into the charge chamber of a gun barrel. The CBH material can be composed of nitrocellulose, fuel cell (cellulose), resin (plastic), stabilizers, and / or optionally, other additives.

[0033] The aforementioned problem is also solved by an ignition arrangement for a tubular weapon with the features of the dependent claim. Regarding the achievable advantages, reference is made to the corresponding descriptions concerning the propellant charge. The ignition arrangement is designed and / or intended for a tubular weapon. The ignition arrangement comprises a high-frequency generator, a high-frequency conductor connected to the high-frequency generator, a transmitting antenna connected to the high-frequency conductor for transmitting microwaves, and a propellant charge with one or more of the aspects described above. If the propellant charge is arranged adjacent to the transmitting antenna and the high-frequency generator is activated, the propellant charge can be ignited by spark discharge, as described above.

[0034] Preferably, the ignition arrangement can include a power supply and / or control unit that is electrically and / or electronically connected to the high-frequency generator. This allows the high-frequency generator to be supplied with electrical energy and, if necessary, controlled accordingly.

[0035] Further development can be achieved using the measures described in connection with the propellant charge and / or those explained below.

[0036] The aforementioned problem is also solved by a tube weapon with the features of the dependent claim. Regarding the achievable advantages, reference is made to the relevant explanations concerning the propellant charge.

[0037] The barreled weapon features an ignition system with one or more of the aspects described above. As described above, the ignition system allows the propellant charge to be ignited by spark discharge. This enables the firing of a projectile located in the weapon barrel. Due to the parallel ignition of the propellant charge at multiple points and, if necessary, in multiple propellant charge modules, a particularly uniform ignition can be achieved, thus largely preventing pressure pulsations.

[0038] The barrel-shaped weapon, in addition to the ignition arrangement described above, has as its essential components a barrel and a breechblock. The barrel has a first section containing the bore, through which the projectile passes after the propellant charge is ignited. The barrel also has a second section containing the propellant chamber and the breechblock. The breechblock can be closed from the rear (away from the first section of the barrel).

[0039] The construction of the barrel weapon is described in more detail below. The measures described above and / or explained below can be used for further modification of the barrel weapon.

[0040] The aforementioned problem is solved by a method for igniting a propellant charge for a barrel weapon, the process steps of which are described below. Regarding the advantages achievable with this method, reference is made to the relevant explanations concerning the propellant charge.

[0041] The proposed procedure stipulates that a

[0042] A high-frequency signal is generated and transmitted, creating a microwave field. This can be achieved using a high-frequency generator, a high-frequency conductor, and a transmitting antenna, as described above.

[0043] The method also provides that the propellant charge is exposed to the microwave field, so that a voltage is induced on propellant grains of the propellant charge, on each of which a thin-film resonator is applied, which surrounds the respective propellant grain and has one or more (microwave-sensitive) spark gaps, whereby when the (local) breakdown voltage is reached at the spark gap(s) sparks jump, thereby igniting the propellant charge (ignition by spark discharge).

[0044] In a preferred embodiment, the jumping sparks can ignite the respective propellant grain itself (directly). This allows for high-energy combustion with high gas volume production.

[0045] Alternatively, the jumping sparks can ignite a pyrotechnic ignition mixture, which is arranged as an intermediate layer between the thin-film resonator and the propellant pellet. This allows for a simple and potentially faster ignition of the propellant pellets, as explained above.

[0046] The measures described above and / or discussed below can be used to further develop the method. The invention is explained in more detail below with reference to the figures, where identical or functionally equivalent elements are provided with identical reference numerals, possibly only once. The figures show:

[0047] Fig. 1 shows a design form of a propellant grain of the propellant charge in a perspective exploded view;

[0048] Fig. 2 shows a schematic sectional view of a tubular weapon with a propellant charge arranged in the charge chamber, comprising propellant charge grains from Figure 1;

[0049] Fig. 3 different basic forms G of resonant structures;

[0050] Fig. 4 shows various forms of resonant structures derived from the basic forms G; and

[0051] Fig. 5 further forms of resonant structures derived from the basic forms G.

[0052] A propellant charge 100 that can be ignited by microwaves is shown in Figure 2 and is arranged there by way of example in the form of several propellant charge modules 102 in the charge chamber 214 of a tubular weapon 200.

[0053] The propellant charge 100 comprises a plurality of propellant grains 10, or in other words, is composed of a plurality of propellant grains 10. At least some of the propellant grains 10 each have a thin-film resonator 16 applied, which surrounds the respective propellant grain 10 and has one or more spark gaps 18 (see Figure 1). The structure of the propellant charge 100 is explained below with reference to the propellant grain 10 shown in Figure 1.

[0054] In this example, the propellant grain 10 extends along a central longitudinal axis 12 and has a cylindrical shape with a circular cross-section. The propellant grain 10 has several channels 14 extending parallel to the central longitudinal axis 12 and penetrating the propellant grain 10. The propellant grain 10 can consist of the materials described above.

[0055] As part of one possible design, the thin-film resonators 16', 16'' are configured as a foil 20 consisting at least partially of metal and featuring a structured pattern (see Figure 1). The structured pattern comprises several structuring elements which together form the overall structure. These structuring elements could, in principle, be raised areas or depressions.

[0056] In this example, the structuring is designed as a perforation, which is evenly distributed over the entire thin-film resonator 16', 16''. The perforation in this example has several perforation elements 22, 24.

[0057] In a first embodiment of the thin-film resonator 16' (see Figure 1, top right), the perforation elements 22 are each formed as circular openings 23 (perforated perforation). Each perforation element 22 can form a spark gap 18. The openings 23 penetrate the film 20 completely along its thickness direction. In this example, the openings 23 are arranged in a defined pattern, specifically in several columns and rows, on the film 20. The perforation elements 22, and thus the openings 23, each form a spark gap 18.

[0058] In a second embodiment of the thin-film resonator 16'' (see Figure 1, top center), the perforation elements 24 are each designed as slots 25 (slotted perforation). The slots 25 each extend along a slot longitudinal direction 28 and are oriented parallel to each other. In this example, the slot longitudinal direction 28 is oriented parallel to the central longitudinal axis 12, along which the propellant grains 10 extend. Here, the perforation elements 24, and thus the slots 25, each form a spark gap 18.

[0059] In a third embodiment, the thin-film resonator 16' '' is configured as a coating 30 containing metallic particles 32 (see Figure 1, top left). Here, a spark gap 18 is formed between each pair of adjacent metal particles 32. The metal particles 32 can be configured as metal grains, metal flakes, or a mixture thereof. The metal particles 32 can be embedded in a matrix material 34 and attached to the propellant grain 10 via this matrix material.

[0060] As explained above, a propellant charge of 100 also includes a

[0061] A combination of propellant grains 10 with a structured metallic foil 20 as a thin-film resonator 16 and of propellant grains 10 with a particle-laden coating 30 as a thin-film resonator 16 is conceivable.

[0062] Optionally, a pyrotechnic ignition mixture 38 can be arranged as an intermediate layer 36 between the propellant grain 10 and the thin-film resonator 16.

[0063] Figure 2 shows the Rohrwaffe 200 in a schematic sectional view.

[0064] The gun 200 comprises a barrel 202 and a breechblock 204. The barrel 202 has a first section 206, in which the bore 208 is located, into which a projectile 210 is inserted and, if necessary, attached. After ignition of the propellant charge 100, the projectile 210 passes through the bore 208 towards the muzzle due to the combustion of the propellant charge 100 and the increasing pressure (direction of fire to the right in Figure 2; muzzle not shown). The gun barrel 202 also has a second section 212, in which a charge chamber 214 of the gun for receiving the propellant charge 100 and the breechblock 204 are located.

[0065] The propellant grains 10, designed according to one of the above-mentioned configuration options, are distributed in the main charge (powder bed) of the propellant charge 100, the propellant charge 100 here only as an example comprising several propellant charge modules 102, namely three propellant charge modules 102.

[0066] Although the example shows a caseless design in which the propellant charge 100 and the projectile 210 are not connected to each other by, for example, a cartridge case, the use of the described propellant charge 100 or the propellant charge grains 10 is also conceivable with cartridge ammunition.

[0067] The propellant charge 100 or the propellant charge modules 102 can each be partially or completely filled with prepared propellant charge grains 10 (propellant charge grains 10 with thin-film resonator 16). If only a portion of the propellant charge grains 10 contained in the propellant charge 100 or the propellant charge modules 102 is prepared, these prepared propellant charge grains 10 can serve as initial points for igniting further, unprepared (non-microwave-sensitive) propellant charge grains 100.

[0068] The propellant charge 100 and its propellant charge modules 102 are arranged in the charge chamber 214 of the gun 200. In front of the propellant charge 100, in the direction of fire (pointing to the right in Figure 2), is the projectile 210. Behind the propellant charge 100, the charge chamber 214 is sealed gas-tight by the breechblock 204.

[0069] Within the breechblock 204, facing the propellant charge 100, a transmitting antenna 152 for inducing a microwave field into the charge chamber 214 and a gas-tight high-frequency conductor 154 (HF conductor) integrated into the breechblock 204 are arranged. The transmitting antenna 152 is connected to the high-frequency conductor 154. The high-frequency conductor 154 can be configured as a waveguide or a coaxial conductor.

[0070] The transmitting antenna 152 and the high-frequency conductor 154 are supplied with a high-frequency signal (HF signal) by a high-frequency generator 156 (HF generator) located externally on the closure 204. The high-frequency conductor 154 is connected to the high-frequency generator 156. The high-frequency generator 156 can be supplied with electrical energy and, if necessary, controlled by an external power supply and / or control unit 158. The power supply and / or control unit 158 ​​is electrically and / or electronically connected to the high-frequency generator 156, in particular via a wired connection. The transmitting antenna 152, the high-frequency conductor 154, the high-frequency generator 156, and the power supply and / or control unit 158, optionally together with the propellant charge 100, form an ignition arrangement 150.

[0071] As previously indicated, the microwave field is induced into the charge chamber by the transmitting antenna 152. The high-frequency signal therefore does not need to pass through any munition-side connection, but only needs to be electrically insulated and gas-tightly guided into the charge chamber 214.

[0072] The gas-tight transmission of the high-frequency signal into the charge space 214 can be implemented more easily with conventional construction methods and materials than an optical feedthrough for laser ignition and is insensitive to deposits.

[0073] If a primer magazine is present, the weapon-side part of the ignition arrangement 150 can be adapted to the existing geometry on the breech 154.

[0074] The ignition of the propellant charge 100 proceeds as follows: A high-frequency signal is generated in the high-frequency generator 156 and transmitted via the high-frequency conductor 154 to the transmitting antenna 152. The transmitting antenna 152 then emits a high-frequency signal which creates a microwave field in the charge chamber 214 of the muzzle-loaded weapon 200 and the propellant charge 100 located therein. Due to the spatial distribution of the microwave field, a locally variable voltage is induced in the thin-film resonators 16 of the propellant charge grains.

[0075] Due to the voltage gradient within the thin-film resonator 16, sparks can jump across the defined or arbitrarily formed spark gaps 18 when the local breakdown voltage of the air is reached. The sparks ignite any ignition mixture 38 present on the surface of the propellant grains 10 or the propellant grains 10 themselves, thereby initiating the combustion of the entire propellant charge 100.

[0076] All propellant charge modules 102 within the charge chamber 214 can be ignited virtually simultaneously. Even within a single propellant charge module 102, ignition can be initiated at multiple points by spark discharge through the field configuration and distribution of thin-film resonators 16 and their spark gaps 18. This contributes to a particularly uniform ignition, minimizing any pressure pulsations.

[0077] Figure 3 shows different basic shapes G of resonant structures. The first row of Figure 3 shows, as examples, a rectangle, a triangle, an annulus, and a dipole. The second row of Figure 3 shows, as examples, a circle, a square, and an ellipse. For clarity, not every basic shape G is labeled with a reference symbol (the same applies to Figures 4 and 5).

[0078] As explained above, the structuring, for example as a perforation, represents a resonant (microwave-sensitive) structure. A resonant structure generates so-called field peaks or areas of high EM field through an electromagnetic field (EM field), so that a corresponding voltage potential is formed and the breakdown field strength or breakdown voltage is exceeded, so that a plasma or flashover is formed by ionization.

[0079] Figures 4 and 5 each show forms derived from the basic forms G, in which the respective basic form G is repeated once or several times.

[0080] The thin-film resonators 16 can, instead of the geometries described above, also have the derived shapes shown here and enclose the propellant charge grain(s) 10 j in such a configuration.

Claims

Patent claims 1. Propellant charge (100) for a cannon (200) , with a plurality of propellant charge grains (10) , characterized in that at least on some of the propellant charge grains (10) a thin-film resonator (16) is applied, which surrounds the respective propellant charge grain (10) and has one or more spark gaps (18).

2. Propellant charge (100) according to claim 1, characterized in that the thin-film resonators (16) are each designed as a foil (20) consisting at least partially of metal with a structuring.

3. Propellant charge (100) according to claim 2, characterized in that the structuring is designed as a perforation.

4. Propellant charge (100) according to claim 1, characterized in that the thin-film resonators (16) are each designed as a coating (30) containing metallic particles (32).

5. Propellant charge (100) according to claim 1 or 2, characterized in that a pyrotechnic ignition mixture (38) is arranged as an intermediate layer (36) between the propellant charge grain (10) and the thin-film resonator (16).

6. Propellant charge (100) according to one of the preceding claims, characterized in that the majority of the propellant charge grains (10) or all Each propellant charge grain (10) has a thin-film resonator (16) applied to it.

7. Propellant charge (100) according to one of the preceding claims, characterized in that the propellant charge grains (10) are enclosed in one or more containers.

8. Ignition arrangement (150) for a cannon (200) , comprising a high-frequency generator (156) , a high-frequency conductor (154) connected to the high-frequency generator (156) , a transmitting antenna (152) connected to the high-frequency conductor (154) for transmitting microwaves and a propellant charge (100) according to one of the preceding claims .

9. Pipe weapon (200) with an ignition arrangement (150) according to the preceding claim.

10. Method for igniting a propellant charge (100) , the method comprising the following steps: - Generating and transmitting a high-frequency signal, so that a microwave field is built up, - Applying the microwave field to the propellant charge (100) so that a voltage is induced on propellant charge grains (10) of the propellant charge (100), on each of which a thin-film resonator (16) is applied, which surrounds the respective propellant charge grain (10) and has one or more spark gaps (18), whereby when the breakdown voltage is reached at the spark gap(s) (18) sparks jump, thereby igniting the propellant charge (100).

11. Method according to claim 10, characterized in that the jumping sparks each ignite the respective propellant grain (10) itself.

12. Method according to claim 10, characterized in that the jumping sparks constitute a pyrotechnic Ignite the ignition mixture (38), which is arranged as an intermediate layer (36) between the thin-film resonator (16) and the propellant grain (10).

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