Patent Application
20240361107
The present disclosure relates generally to improvements in shaped charge systems employing electronic safe and arm devices and to methods of their use. More particularly, the disclosure pertains to minimizing space requirements for safe and arm devices in shaped charge systems and concomitantly preventing premature detonation due to shaped charge liner collapse.
Shaped charges are employed in warheads, oil well perforation systems and other explosive mechanism systems, and involve shaping of detonation waves in contained explosive material to enhance explosive performance. A waveshaper, typically an inert structure, is positioned rearwardly of a billet of explosive material and configured to cause the forwardly directed detonation wave to travel around the waveshaper through the explosive material and then converge to explosively increase pressure on the billet liner. Examples of such shaped charge explosive systems are disclosed in the following patent documents, the entire disclosures in which are incorporated herein by reference: U.S. Pat. No. 2,809,585 (Moses); U.S. Pat. No. 5,565,644 (Chawla); U.S. Pat. No. 6,193,991 (Funston et al); U.S. Pat. No. 6,467,416 (Daniels et al); U.S. Pat. No. 7,040,234 (Maurer et al); U.S. Pat. No. 7,752,972 (Baker et al); U.S. Pat. No. 7,975,502 (Bell et al); US2003/0140811 (Bone), US20060266247 (Gilliam et al); US20130061771 (Betancourt et al) and DE102010018187 (Werner et al).
It is also known to provide electronic safe and arm devices (ESAD) for shaped charge systems to prevent unintended detonation of their explosive fill material; see, as examples, U.S. Pat. No. 6,295,932 (Kane), U.S. Pat. No. 7,240,617 (Bonbrake et al), and U.S. Ser. No. 10/615,695 (Pirozzi et al), the entire disclosures in which are also incorporated herein by reference, as well as the aforementioned Maurer et al, Bone, and Gilliam et al patent documents.
One example of a prior art shaped charge warhead is illustrated schematically
Typically, if an ESAD is added to the warhead, its protective circuitry and firing components would be housed with the detonator adjacent the outside surface of the rear end wall 13, thus adding a not insignificant amount of additional space for an overall system in which space is at a premium. For example, an ESAD includes circuitry (typically on a PC board) to isolate a high voltage power source from a detonator to inhibit inadvertent firing of the system. See, for example, see: U.S. Pat. No. 4,421,030 (DeKolker), U.S. Ser. No. 10/197,372 (Grace et al), U.S. Ser. No. 10/615,695 (Pirozzi et al), the entire disclosures in which are incorporated herein by reference. It would be desirable to provide the warhead or other shaped charge explosive system with an ESAD or other safe and arm feature without substantially increasing the occupied volume or space of the overall system. The systems and methods disclosed herein address this goal.
Another consideration in shaped charge systems is the potential for premature detonation. For example, to initiate detonation of the explosive billet, an impact switch or sensor may be positioned at the forward end of the casing such that, upon impact of the forward end with a target, the impact sensor sends an electrical signal to the ESAD and detonator to thereby detonate the billet of explosive fill material. Or, as described above, rather than detonating the fill material directly, detonation may be effected by booster pellets of a primary explosive material that, when electrically stimulated, create a small explosion that causes the billet material to explode. Alternatively, initiation may be effected by an accelerometer which, in cooperation with a microprocessor, determines the proper time for detonation based on warhead velocity dynamics. See, for example, the discussion in U.S. Pat. No. 5,225,608 (Min et al), the entire disclosure in which is incorporated herein by reference. In any case, upon a detonate signal being sent to the ESAD, the explosive fill material is detonated, causing the shaped charge liner to be forcefully compressed and propelled forwardly as a shaped charge jet. In certain scenarios, the warhead could potentially impact a structural target with enough force to cause the shaped charge liner to collapse before detonation occurs. This collapse may cause the explosive material, waveshaper, and booster to lurch forward and pull away from the detonator prior to the ESAD, thereby allowing the detonator high voltage switch to close and the detonator to fire prematurely. The systems and methods disclosed herein also address this problem.
This Summary is provided to introduce a selection of concepts in a simplified form, the concepts being more specifically described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter.
The systems and methods disclosed herein focus on providing solutions to the above-described problems by separating the detonator and high voltage switching components from the other ESAD components and, more particularly, embedding those separated components within the waveshaper structure while maintaining the other ESAD components outside the chamber containing the explosive material. The detonator and fuzing (or firing) circuitry are thus contained entirely within the housing of inert material occupied by the waveshaper within the explosive billet and adds no additional space to the overall system. Relocating the high voltage firing components to within the waveshaper does not change the exterior configuration of the waveshaper and therefore does not affect the primary function of the waveshaper, namely, directing and shaping the detonation wave for the intended shaped charge operation.
Another advantage of separating the detonator and high voltage switching (i.e., fuzing) components from the safe and arm components and housing them within the waveshaper is that the contained firing module components move with the waveshaper and the explosive billet during the first few milliseconds of target impact, thereby avoiding their separation and premature detonation.
In one aspect, a shaped charge system comprises a billet of explosive fill material, a waveshaper disposed in the explosive material, and a detonator and firing module disposed within the waveshaper.
In another aspect a shaped charge system comprises a casing defining an interior chamber and having forward and rearward ends, a shaped charge liner disposed in the chamber, a billet of explosive fill material disposed in the chamber rearwardly of the liner, a waveshaper disposed in the explosive material between the rearward end of the chamber and the liner and a detonator and firing module disposed in said waveshaper.
In still another aspect, a method for initiating detonation waves in a shaped charge system comprises initiating an electrical detonation signal from an electronic safe and arm device located outside a chamber containing a billet of explosive material, and creating detonation waves in the explosive material from within a waveshaper embedded in the explosive material.
By way of example, specific illustrative systems of the present disclosure will now be described with reference to the accompanying drawings in which like reference numerals in the various figures represent similar of like components.
The present systems and methods are described more fully hereinafter with reference to the accompanying drawings. It will be readily understood that the components of the systems and methods as generally described herein and illustrated in the appended drawings may be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of systems and methods, as represented in the drawings, is not intended to limit the scope of the present disclosure but is merely representative of various systems and methods. While various aspects are presented in the drawings, the drawings are not necessarily drawn to scale unless specifically indicated.
The techniques and approaches disclosed herein may be implemented in other specific forms without departing from its spirit or essential characteristics; that is, the described implementations are to be considered in all respects only as illustrative and not restrictive. The scope of inventions disclosed herein is therefore indicated by the appended claims rather than by this detailed description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.
Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the disclosed apparatus, system and method should be or are in any single implementation. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an implementation is included in at least one implementation. Thus, discussions of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same implementation.
Furthermore, the described features, advantages, and characteristics of the disclosed principles may be combined in any suitable manner in one or more implementations. One skilled in the relevant art will recognize, in light of the description herein, that the implementations can be practiced without one or more of the specific features or advantages of a particular implementation. In other instances, additional features and advantages may be recognized in certain implementations that may not be present in all implementations.
Reference throughout this specification to “one implementation,” “an implementation,” or similar language means that a particular feature, structure, or characteristic described in connection with the indicated implementation is included in at least one implementation. Thus, the phrases “in one implementation,” “in an implementation,” and similar language throughout this specification may, but do not necessarily, all refer to the same implementation.
The relative terms “forward”, “rear”, “length”, “width”, “thickness”, and the like as used herein are for ease of reference in the description to merely describe points of reference and are not intended to limit any particular orientation or configuration of the described subject matter.
Referring to the schematic illustration in
In operation, the safe and arm circuitry 25 detects conditions indicative of warhead launch and safe separation. Once the warhead is safely away from the launch platform the system is armed and high voltage is generated to await a trigger event. Upon receipt of a trigger signal either through electrical wiring or on-board sensors, detonator 23 is activated to initiate the detonation wave into the explosive billet 16 behind the waveshaper 18. The predetermined outer configuration of the waveshaper is not changed by the internally located firing components and detonator, and therefore performs its intended detonation waveshaping function in a manner similar to that described above in connection with
Referring to
An aft closure region 31, located just outside the chamber at the rearward end of the system, contains an electronic safe and arm module (ESAD) 38 from which a booster explosive, in the form of explosive booster pellets 39, extend through an access opening in the rearward end wall of the chamber into the chamber to the waveshaper 34. The booster pellets are surrounded by electrical connections extending between the ESAD module 38 and firing module 35 for activating the firing module and detonator 36 when the circuitry in the ESAD module is triggered.
In operation, under the appropriate conditions as described above, the circuitry in safe and arm module 38 triggers the firing module 35 to cause high voltage in the firing module to activate the booster pellets 39. The booster pellets initiate a detonation wave which travels into the explosive billet 33 adjacent the wave shaper 34 and then propagates around the wave shaper.
As will be appreciated, an aspect of present disclosure resides in the fact that the waveshaper 34 of inert material is configured to contain the described high voltage switching circuit of firing module 35 and detonator 36, thereby conserving system space. In addition, these contained components can remain in close proximity to the explosive fill material 33 in the chamber throughout a high shock event. The ESAD components are disposed outside the chamber and supply requisite signals to the high voltage switching circuit via wiring or copper traces surrounding the booster pellet structure.
A modified version of the warhead is illustrated in
An aspect of this disclosure is the separation of the safe and arm components from the firing module components, which are normally housed together at the rearward end of the warhead or other shaped charge system, such that the firing module components are placed inside the waveshaper. The benefit of this is two-fold, namely: (1) valuable space is saved by not requiring separate space for the firing module; and (2) the firing module components move with the explosive billet during the first few milliseconds after target impact thus maintaining intimate contact between the detonation components and high explosive fill material and assuring reliable detonation of the main explosive charge.
In conclusion, provided for herein are techniques that solve the problem of minimizing the space required for components in a shaped charge system employing an electronic safe and arm device while concomitantly eliminating separation of detonation components from the explosive fill material. This is achieved by separating the firing module components from the ESAD components and, more particularly, embedding the detonator and firing module in the waveshaper, which is embedded in the explosive material, while maintaining the position of the ESAD components outside the system chamber containing that material.
The above description is intended by way of example only. Although the techniques are illustrated and described herein as embodied in one or more specific examples, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made within the scope and range of equivalents of the claims.
