US20110107936A1

US20110107936A1 - Action device for graduated explosive effect and a process for the same

Info

Publication number: US20110107936A1
Application number: US12/997,434
Authority: US
Inventors: Mats Runemard
Original assignee: BAE Systems Bofors AB
Current assignee: BAE Systems Bofors AB
Priority date: 2008-06-11
Filing date: 2009-05-20
Publication date: 2011-05-12
Also published as: EP2300775A1; SE0801359L; WO2009151363A1; SE532521C2

Abstract

The invention relates to an action device (1) designed for graduated explosive effect, especially intended to form part of a shell body (2) for firing from a gun barrel, which action device comprises at least two action parts (4, 5, 6) comprising fuel (10) and oxidizer (14), and an activation device (3) for activating the action parts (4, 5, 6), which activation device (3) comprises a detonator (23). The invention is characterized in that the fuel (10) and the oxidizer (14) of the action parts are stored separately up to activation of the action device (1), and in that the detonator (23) and the action parts (4, 5, 6) are designed for the initiation of one or more action parts (4, 5, 6), depending on the grade of explosive effect which is to be obtained. The invention also relates to a process for the said action advice (1).

Description

The present invention relates to an action device designed for graduated explosive effect, especially intended to form part of a shell body for firing from a gun barrel, which action device comprises at least two action parts comprising a fuel and an oxidizer, and an activation device for activating the action parts, which activation device comprises a detonator. The invention also relates to a process for the said action advice.
An action device for graduated explosive effect is normally designed with a plurality of action parts comprising one or more explosive charges, the action parts being mutually separated with barriers to prevent flashover between the action parts. For each action part there is also provided one or more detonators for initiating the explosive charges. The action parts can be activated simultaneously or in sequence with various time delays. The action parts can also comprise an additional material for the achievement of special effects, such as: fire, lighting or smoke effect.
U.S. Pat. No. 4,658,727 discloses an action device comprising a plurality of action parts, in which each action part comprises an explosive charge and at least one detonator. The action parts are mutually separated with barriers to prevent flashover. The detonators are coupled to an activation unit for activating one or more action parts with regard to a desired grade of effect. In one embodiment, each action part comprises two detonators arranged such that the direction of action can be influenced. At the same time, activation implies an explosive effect at right angles to the longitudinal axis of the action device. A time delay, on the other hand, implies a deflection of the explosive effect in the one or other direction.
Action devices according to U.S. Pat. No. 4,658,727, having a plurality of detonators connecting to the explosive charges of the action parts, imply an increased risk of accidental initiation. A plurality of detonators for controlling the grade of effect imply, moreover, a relatively complex system.

PURPOSE OF THE INVENTION AND ITS DISTINGUISHING FEATURES

A main object of the present invention has been to provide an improved action device for graduated explosive effect, especially intended to form part of a shell for firing from a gun barrel, in which the risk of accidental initiation has been eliminated or severely reduced.
A further object of the present invention has been a process for the said action device.
These objects, as well as other purposes which have not been listed here, are satisfactorily met within the scope of that which is stated in the present independent patent claims.
Thus, according to the present invention, an improved action device for graduated explosive effect has been provided, especially intended to form part of a shell for firing from a gun barrel, in which the risk of accidental initiation has been eliminated or severely reduced.
The action device comprises at least two action parts comprising a fuel and an oxidizer, and an activation device for activating the action parts, which activation device comprises a detonator. Characteristic thereof is that the fuel and the oxidizer are separated up to activation and that the detonator and the action parts are designed for the initiation of one or more action parts, depending on the grade of explosive effect which is to be obtained.
According to further aspects of an action device according to the invention:
the oxidizer is arranged in oxidizer containers and the fuel is arranged in fuel containers, which oxidizer containers are tubular and are arranged between the activation device and the fuel containers, the oxidizer containers comprising radially arranged oxidizer outlets connecting to the fuel containers, and the oxidizer outlets being sealed with openable oxidizer seals,
the oxidizer seals comprise plastics foils arranged on the inner side of the oxidizer containers,
the activation device comprises a pressure container, which pressure container contains pressurized gas, and in the pressure container there are arranged gas outlets connecting to the oxidizer containers, which gas outlets are sealed with openable seals,
connecting to the openable seals, opening devices are provided, which opening devices can be activated in response to an activation signal from a control unit,
the openable seals are constituted by rupture plates,
the opening devices are constituted by a rupture wire arranged on the openable seals,
the fuel comprises a cohesive porous fuel structure for the realization of a large active surface,
the porous fuel structure is coated with a picric acid for increased initiability of the fuel-oxidizer mixture,
the porous fuel structure is coated with a pyrophorous substance for the realization of a self-initiating fuel-oxidizer mixture,
the fuel comprises a compacted powder with high porosity,
the oxidizer comprises an oxygen gas for rapid mixture between fuel and oxidizer.
According to the present invention, there has also been provided a process for an action device designed for graduated explosive effect, especially intended to form part of a shell body for firing from a gun barrel, comprising at least two action parts comprising a fuel and an oxidizer, and an activation device for activating the action parts, which activation device comprises a detonator. Characteristic thereof is that the fuel and the oxidizer of the action parts are stored separately up to activation and that the detonator and the action parts are designed for the initiation of one or more action parts, depending on the grade of explosive effect which is to be obtained.

ADVANTAGES AND EFFECTS OF THE INVENTION

The invention has a number of advantages and effects. The fact that the fuel and the oxidizer of the action parts are stored separately up to the point of use enables the action device to be safely handled, from manufacture, storage and transport to handling of the action device in weapons and during recovery and destruction. Only when an action part is activated, that is to say when fuel and oxidizer are mixed and explosive mixture commences, does the action device pose a risk.
The recovery process is simplified by the fact that fuel and oxidizer are already separated and no further operations are required.
The fact that one detonator is used to initiate one or more action parts allows a simpler activation system compared with if a plurality of detonators are used.

Further advantages and effects will emerge during a study and consideration of the following detailed description of the invention, including a number of its most advantageous embodiments, patent claims and appended drawing figures, in which:

FIG. 1 shows a longitudinal section of an action device,

FIG. 2 shows an enlargement of the activation device for the action device in FIG. 1,

FIG. 3 shows a part-enlargement of an oxidizer container according to the action device in FIG. 1.

DETAILED DESCRIPTION

In FIG. 1 is shown a first embodiment of an action device 1 designed for graduated explosive effect. By graduated explosive effect is here meant an explosive effect which can be gradually altered, in a number of steps, from low to medium-high explosive effect and from medium-high to high explosive effect, depending on how many action parts 4, 5, 6 are activated. The number of steps depends on how many action parts are included in the action device.
The action device 1 is contained in a shell body 2 between the front part of the shell body 2, also referred to as the nose part, and the rear part of the shell body 2.
The action device 1 comprises three action parts 4, 5, 6, axially arranged one behind the other in the longitudinal axis A of the shell body 2, the front action part 4 of the action device being arranged closest to the nose part of the shell body, followed by the intermediate action part 5 of the action device 1 and a rear action part 6 thereof. The action device 1 also comprises an activation unit 3 for activating one or more action parts 4, 5, 6. The activation unit 3 is arranged between the nose part of the shell body 2 and the front action part 5. Each action part 4, 5, 6 comprises a fuel container 7, 8, 9 containing a fuel 10, and an oxidizer container 11, 12, 13 containing an oxidizer 14. The front action part 4 comprises a front fuel container 7 and a front oxidizer container 11.
The intermediate action part 5 comprises an intermediate fuel container 8 and an intermediate oxidizer container 12. Finally, the rear action part 6 comprises a rear fuel container 9 and a rear oxidizer container 13.
The fact that fuel 10 and oxidizer 14 are stored separately from each other in the respective fuel containers 7, 8, 9 and oxidizer containers 11, 12, 13 up to activation of the action device 1, that is to say when fuel 10 and oxidizer 14 are brought together and thereby form an explosive mixture, allows the action device to be safely handled, with minimal risk of accidental initiation. Between the action parts 4, 5, 6 there are arranged barriers 15, 16, 17 for preventing oxidizer 14 from spreading between the action parts 5, 6, 7. The barriers 15, 16, 17 are gas-tight and liquid-tight and consist, preferably, of a plastics or metal material, for example in the form of foil. The plastics or metal foil can be fitted on the inner side of the shell body 2, for example with a weld joint. Alternatively, the barriers 15, 16, 17 can be arranged such that they enclose the fuel containers 7, 8, 9.
The barriers 15, 16, 17 are dimensioned such that they break under the pressure generated with a detonation. The detonation from the action part 4 initiates the action part 5, and the detonation from the action part 5 initiates the action part 6. By virtue of the said arrangement, only one detonator 23 is thus required for the initiation of one, two or three action parts, depending on the grade of explosive effect which is to be obtained. A precondition is, however, that the fuel 10 and the oxidizer 14 in the initiated action parts 4, 5, 6 have commenced explosive mixture, i.e. have been mixed.
As is shown in FIG. 2, the activation unit 3 comprises a pressure container 18, preferably a cylinder with closed ends. The pressure container 18 is pressurized with a gas 19, preferably an inert gas, for example helium, nitrogen or argon. The activation unit 3 further comprises three gas outlets 20, to which the three oxidizer containers 11, 12, 13 are connected. The gas outlets 20 are, initially, closed off with openable seals 21 to prevent the pressurized gas 19 from streaming out into the oxidizer containers 11, 12, 13 prior to activation. The seals 21 are constituted, preferably, by rupture plates 21. Directly connected to the seals 21 there are also arranged opening devices 22 for opening the seals 21 in response to an activation signal from a control unit 24, referred to as a CPU (Control Process Unit) 24. One or more seals 21 can be opened independently of each other. The opening device is constituted, preferably, by a rupture wire/detonating cord 22 fitted on the seals 22. Alternatively, the opening devices 22 can comprise pyrotechnic charges 22 fitted on the seals 21.
Other types of opening devices 22 also can possibly be used, for example electromagnetic devices in which plungers or needles (not shown) are activated to puncture the seals 21.
The opening devices 22 are electrically activated via the CPU unit 24 in the nose part of the shell body 2, either by a preset activation program or by a signal from an active target-seeking sensor 25.
The oxidizer containers 11, 12, 13 are axially arranged in the shell body 2 between the activation unit 3 and the fuel containers 7, 8, 9. The front oxidizer container 11 runs from the activation unit 3 through the front fuel container 7 up to the front barrier 15.
The intermediate oxidizer container 12 runs from the activation unit 3 parallel with the front oxidizer container 11, through the front fuel container 7 and onward through the intermediate fuel container 8, up to the intermediate oxidizer barrier 12. The rear oxidizer tank 13 runs from the activation unit 3 parallel with the front 11 and the intermediate oxidizer container 12 up to the rear oxidizer barrier 16. That part of the oxidizer containers 11, 12, 13 which is located in the respective fuel container 7, 8, 9 comprises radially arranged oxidizer outlets 26. The oxidizer outlets 26 are, initially, sealed with gas-tight openable oxidizer seals 27. The openable oxidizer seals 27 are constituted, preferably, by plastics or metal foil arranged on the inner side of the oxidizer containers 11, 12, 13. Alternatively, the oxidizer seals 27 are constituted by rupture plates 27 arranged either on the outer side or on the inner side of the oxidizer outlets 26. The oxidizer seals 27 are openable in response to a specific pressure increase in the oxidizer containers 11, 12, 13.
The pressure increase in the oxidizer containers 11, 12, 13 is generated by the pressurized gas 19 after the opening device 22 has been activated. The gas pressure in the oxidizer containers 11, 12, 13 rises rapidly, leading to a rupturing of the oxidizer seals 27.
The pressure increase means that the oxidizer 14 is forced out into the fuel containers 7, 8, 9 via the oxidizer outlets 26 and fills the pore structure of the fuel 10.
The oxidizer containers 11, 12, 13 consist, preferably, of stainless steel in order to cope with the storage of corrosive gas, but can also consist of corrosion-resistant plastic. The oxidizer 14 is gaseous or liquid and comprises oxygen gas, nitrous oxide, nitric acid or hydrogen peroxide, or mixtures thereof.
Alternatively, the oxidizer 14 can be constituted by dinitramide salt dissolved in a suitable solvent, for example dimethyl formamide or tetrahydrofuran, or mixtures thereof.
The fuel 10 is preferably constituted by a cohesive porous fuel structure 10, consisting of silicon, carbon, vanadium, beryllium, magnesium, iron, or mixtures thereof. The highly porous fuel 10 is configured for the quickest possible absorption of a gaseous or liquid oxidizer 14 by the fuel 10 being arranged in the form of thin porous discs at a certain distance apart in the fuel containers 7, 8, 9. The porous fuel 10 has a porosity, preferably, within the range 60 to 95% by volume. Alternatively, the fuel 10 can comprise a fine-grained, compacted powder 10 comprising silicon, carbon or vanadium, beryllium, magnesium, iron, or mixtures thereof. The powder mixture 10 has a porosity and structure which, upon contact with a gaseous or liquid oxidizer 14, in the course of initiation, can be made to detonate.
In a second embodiment, not shown in the figures, the cohesive porous fuel structure 10 is coated with an additive to facilitate the initiation of the fuel/oxidizer mixture. The additive can advantageously consist of a fine-grained zirconium powder, evenly distributed in the pore structure of the fuel 10. In order further to increase initiability, the additive can also be mixed with a primer, for example picric acid. In a further special variant, the pore structure of the fuel 10 is coated with a pyrophorous substance, which, upon contact with the oxidizer 14, leads to spontaneous ignition, which spontaneous ignition initiates the fuel-oxidizer mixture. The advantage is that no further initiation via a detonator is required.
In a third embodiment, not shown in the figures, the oxidizer 14 is stored together with the pressurized gas in the pressure containers 18. The oxidizer containers 11, 12, 13 for the storage of oxidizer 14 thus become superfluous. The function of the oxidizer containers 11, 12, 13 is instead to act as transport ducts for transporting the oxidizer 14 up to the fuel containers 7, 8, 9. The oxidizer containers 11, 12, 13 can hence be simplified by being made thinner and narrower.
After oxidizer 14 and fuel 10 have been mixed in one or more action parts 4, 5, 6, depending on the intended grade of explosive effect, the front action part 4 is initiated. The front action part 4 in turn initiates the intermediate action part 5, and the intermediate action part 5 initiates the rear action part 6, subject to these having been activated. Initiation of the action part 5 takes place after a specific time delay from activation having been realized.
The time delay can be pre-programmed via a time relay or via a pyrotechnic delay unit. Alternatively, the time delay can be determined by a target-seeking sensor during the flight of the shell towards a target. The target-seeking sensor can be of the radar or laser type. Alternatively, the time delay can be determined from a ground control via radar or IR link.
The speed with which the oxidizer 14 is distributed in the pore structure of the fuel 10 is determined primarily by the gas pressure in the pressure container and by the physical properties, e.g. porosity, of the fuel 10, but also by the rotational velocity of the shell body 2. High rotational velocity signifies higher mixing speed, whereas low rotation velocity signifies a lower mixing speed.
Alternative Possibilities Of Use Of The Action Device
The action device 1 according to the invention is especially intended to form part of shells for firing from a gun barrel, the grade of explosive effect from the action device 1 being pre-programmed or being determined during travel of the shell towards a target. Alternatively, the action device 1 can be incorporated in robots, missiles or various types of mines. The action device 1 can also be incorporated in explosive devices for civil use, for example in mining or in road works.

Claims

1. Action device designed for graduated explosive effect, especially intended to form part of a shell body for firing from a gun barrel, which action device comprises at least two action parts comprising a fuel and an oxidizer, and an activation device for activating the action parts, which activation device also comprises a detonator, characterized in that the fuel and the oxidizer are separated up to activation, and in that the detonator and the action parts are designed for the initiation of one or more action parts, depending on the grade of explosive effect which is to be obtained.

2. Action device according to claim 1, wherein the oxidizer is arranged in oxidizer containers and the fuel is arranged in a fuel containers, which oxidizer containers are tubular and are arranged between the activation device and the fuel containers, the oxidizer containers comprising radially arranged oxidizer outlets connecting to the fuel containers, and the oxidizer outlets being sealed with openable oxidizer seals.

3. Action device according to claim 2, the oxidizer seals are constituted by plastics foils. arranged on the inner side of the oxidizer tanks.

4. Action device according to claim 2, the activation device comprises a pressure container, which pressure container contains pressurized gas, and in that in the pressure container there are arranged gas outlets connecting to the oxidizer containers, which gas outlets are sealed with openable seals.

5. Action device according to claim 2, connecting to the openable seals, opening devices are provided, which opening devices can be activated in response to an activation signal from a control unit.

6. Action device according to claim 4, wherein the openable seals are constituted by rupture plates.

7. Action device according to claim 4, wherein the opening devices are constituted by a rupture wire arranged on the openable seals.

8. Action device according to claim 1, wherein the fuel comprises a cohesive porous fuel structure for the realization of a large active surface.

9. Action device according to claim 8, wherein the porous fuel structure is coated with a picric acid for increased initiability of the fuel-oxidizer mixture.

10. Action device according to claim 8, wherein the porous fuel structure is coated with a pyrophorous substance for the realization of a self-initiating fuel-oxidizer mixture.

11. Action device according to claim 1, wherein the fuel comprises a compacted powder with high porosity.

12. Action device according to claim 1, wherein the oxidizer comprises an oxygen gas for rapid mixture between fuel and oxidizer.

13. Action device according to claim 4, wherein the openable seals can be opened independently of each other in response to an activation signal from a control unit.

14. Process for an action device, which action device is designed for graduated explosive effect, especially intended to form part of a shell body for firing from a gun barrel, which action device comprises at least two action parts comprising a fuel and an oxidizer, and an activation device for activating the action parts, which activation device comprises a detonator, characterized in that the fuel and the oxidizer of the action parts are stored separately up to activation, and in that the detonator and the action parts are designed for the initiation of one or more action parts, depending on the grade of explosive effect which is to be obtained.

15. Action device according to claim 5, wherein the openable seals are constituted by rupture plates.

16. Action device according to claim 5, wherein the opening devices are constituted by a rupture wire arranged on the openable seals.

17. Action device according to claim 6, wherein the opening devices are constituted by, a rupture wire arranged on the openable seals.

18. Action device according to claim 2, wherein the fuel comprises a cohesive porous fuel structure for the realization of a large active surface.

19. Action device according to claim 2, wherein the fuel comprises a compacted powder with high porosity.

20. Action device according to claim 2, wherein the oxidizer comprises an oxygen gas for rapid mixture between fuel and oxidizer.