Patent Application
20170176158
The present specification relates to explosion containment, and more particularly to a container allowing safe transport of at least one small explosive device and to blast containing panels for such containers.
Small explosive devices such as detonators, detonating cord, airbag inflators and fuses are widely used and often need to be carried in the presence of others, including the general public.
Upon detonation, rapid combustion processes produced even by a small explosive device compress surrounding fluid media so quickly that shock waves are produced. Also, the physical expansion of the hot blast combustion products adds to pressure loading of objects in its path, as well as generates radiation. The hot blast combustion products are typically capable of igniting combustible materials nearby and inflicting burns on exposed humans. Humans may be killed by intense blast pressure alone, as this causes lung damage above threshold levels. Below threshold conditions for fatal injury, blast pressure may cause damage to ears and lungs, and sudden accelerations that lead to spinal injuries. Moreover, fragments from exploding cased explosive devices may lead to fatal internal damage.
Explosive effects dissipate rapidly in air as long as the blast is unconfined. Large obstructions such as buildings surrounding a street in which a blast occurs prolong pressure durations and lead to greater damaging capability. Complete or near-total confinement maximizes blast effect duration, as the blast pressure is prevented from being dissipated.
In order to provide safe handling of small explosive devices, it is often desired to prevent detonation of one explosive charge from causing detonation of others nearby, an event widely termed “sympathetic detonation”, as mass detonation of large quantities of small explosive charges generates blast parameters equivalent to single-charge detonations of similar weight. A number of prior art small explosive devices containers are designed to prevent sympathetic detonation, but not to confine either blast effect or fragments. As a result, such containers are usually destroyed when the elements contained therein explode, and components are hurled at significant velocities. As such, these containers would be unsuitable for transportation of small explosive devices next to people, as the components projected by the explosion could cause serious injury.
In one aspect, there is provided a container for containing an explosive device, the container comprising: an outer shell including a body and a cover relatively movable between an open position and a closed position; a plurality of blast containing panels including at least a first group of blast containing panels disposed against inner surfaces of the outer shell such as to substantially define an enclosure when the body and the cover are in the closed position, each of the blast containing panels including a fragment-retaining layer and at least one mitigating layer facing the enclosure, each mitigating layer including: a cell structure having an outer wall connected to the fragment-retaining layer and a plurality of cell walls extending from the outer wall, the cell walls forming a plurality of cells having one end closed by the outer wall and an opposed end open, a blast effect mitigating material received within the cells of the cell structure, a fabric layer disposed against and sealing the open end of the plurality of cells, a mesh layer overlaying the fabric layer such that the fabric layer extends between the cell structure and the mesh layer, and a frame connected to the cell structure, the frame forming a perimeter surrounding sides of the cell structure; wherein the mitigating layer is configured to reduce a force of a blast wave caused by an explosion of the explosive device, and the fragment-retaining layer is configured to resist a remainder of the force of the blast wave passing through the mitigating layer and to retain fragments propagated by the explosion.
In another aspect, there is provided a blast containing panel for containing an explosion of an explosive device, the blast containing panel comprising: a fragment-retaining layer; at least one mitigating layer including: a cell structure having an outer wall connected to the fragment-retaining layer and a plurality of cell walls extending from the outer wall, the cell walls forming a plurality of cells having one end closed by the outer wall and an opposed end open, a blast effect mitigating material received within the cells of the cell structure, a fabric layer disposed against and sealing the open end of the plurality of cells, a mesh layer overlaying the fabric layer such that the fabric layer extends between the cell structure and the mesh layer, and a frame connected to the cell structure, the frame forming a perimeter surrounding sides of the cell structure; wherein the mesh layer, cell structure and fabric layer permit transmission of a blast wave caused by an explosion of the explosive device into the blast effect mitigating material; and wherein the mitigating layer is configured to reduce a force of the blast wave, and the fragment-retaining layer is configured to resist a remainder of the force of the blast wave passing through the mitigating layer and to retain fragments propagated by the explosion.
Reference is now made to the accompanying figures in which:
Referring to
The outer shell 12 preferably has a rectangular cross-section, and includes a body 18 and a complementary cover 20 also preferably of rectangular cross-section. In a particular embodiment, the outer shell 12 protects the internal components and materials being transported from weather and incidental damage, and as such is made of a shock resistant plastic, for example a polypropylene copolymer such as Coroplast™. Alternate materials for the outer shell include wood or any appropriate type of metal such as for example steel or aluminum.
In the embodiment shown, the cover 20 is pivotally retained on the body 18 through hinges 22, which are suitable sized and configured to resist a blast from components received inside the case 10. The body 18 and cover 20 also include one or more lock(s) 24 retaining the cover 20 in the closed position when engaged. It is understood that the hinges 22 and/or locks 24 may be configured differently, for example provided on different sides of the body 12 than that shown.
In a particular embodiment, the case 10 is designed to handle small explosive devices (e.g. less than 1 kg total of TNT-equivalent explosive), and as such the hinges 22 and lock(s) 24 allow some gas to escape between the closed cover 20 and the body 18, with the gas leakage and attendant shock waves mitigated to the extent required to prevent permanent injury to nearby people or prevent sympathetic detonation or burning of nearby energetic materials. In an alternate embodiment, the case 10 is used to contain explosive devices and other devices that may contain hazardous biological, radioactive, or chemical agents that could be dispersed under pressure, and as such the seal between the cover 20 and body 18 is adequate to prevent release of the hazardous material. The degree to which the seal is impervious to the transmission of gas can thus be varied through various closure modifications readily available to one in the art.
A handle 26, which may be fixed or extendable, is attached to the body 18 to facilitate transport of the case 10 either by hand or by a robotic device. It is understood that the handle 26 shown herein is exemplary only, and that the handle may be provided in any other appropriate location of the body 18, including but not limited to on another one of its sides. It is also considered to provide the case 10 with more than one handle 26, or alternatively with no handle at all.
It is understood that the particular configuration of outer shell 12 is provided as an example only and that the configuration of the outer shell 12 may vary.
The blast containing panels 15 are located within the outer shell 12. In the embodiment shown, the blast containing panels 15 include a bottom panel 15b and four (4) side panels 15s located in the body 18, and a top panel 15t located in the cover 20, each in contact with the adjacent inner surface of the outer shell 12. The bottom and side panels 15b, 15s preferably abut one another and the panels 15b, 15s, 15t together define an enclosure within the outer shell 12.
The blast containing panels 15 may also include divider panels 15d extending across the enclosure between the opposed side panels 15s, and abutting the bottom panel 15b. In the embodiment shown, the divider panels 15d are disposed in a cross-shaped configuration to separate the enclosure into four compartments insulated from one another by the divider panels 15d. The divider panels 15d may be permanently attached to the adjacent bottom and side panels 15b, 15s, or be removable. Additional removable divider panels 15d may be provided (one of which is shown), for snug insertion into one of the compartments to be able to customize the number and size of separate enclosures defined in the case. In a particular embodiment, the divider panels 15d allow to resist or inhibit the occurrence of sympathetic detonation when more sensitive explosive devices are carried. However, prevention of sympathetic detonation is not essential. In a particular embodiment, in the event of a detonation of one or more explosive devices within the case 10, release of blast generated gas from the case 10 is so slight that no permanent injury is inflicted on humans in close proximity to the case 10. Fragments from explosive device components, and components of the case 10, are preferably completely confined. Extremely rapid cooling of hot gaseous products is also preferable such as to prevent possible ignition of case materials and other items kept within the case 10.
Alternately, the divider panels 15d may be omitted such that the case 10 defines a single enclosure.
Each blast containing panel 15 includes a fragment-retaining layer 14 and at least a mitigating layer 16 facing the enclosure where the explosive will be received. In the embodiment of
Referring to
The open end of the cells 30 is sealed by a fabric layer 34 which is disposed against the open ends. In a particular embodiment, the fabric layer 34 includes a nonwoven textile made with synthetic fibers, made for example of polyester; an example of a suitable material is Pellon® PLF36 Fusible Interfacing. Other materials may be used, included but not limited to materials having similar properties as this material. The fabric layer 34 provides some support to the cell structure 24.
A mesh layer 36 is disposed on the fabric layer 34, and forms the inner surface of the mitigating layer 16. In a particular embodiment, the mesh layer 36 is made of fiberglass. Other materials may be used, including but not limited to mesh materials suitable for use as window screening, such as aluminum mesh.
The mesh layer 36, cell structure 24 and fabric layer 34 contain the blast effect mitigating material 32 within the cells 30, but permits transmission of the impinging blast wave into the blast effect mitigating material 30, for example by provide negligible resistance to or delay in rupture and/or allowing the blast wave to simply pass therethrough.
The cells 30 of the cell structure 24 may be open along the sides of the mitigating layer 16. A frame 38 forms a perimeter surrounding the cell structure 24 to close the side of the cells 30 and provided increased resistance to the mitigating layer 16. In the embodiment shown, the frame 38 has an L-shaped cross-section, including an outer wall 40 extending outwardly of the outer wall 26 of the cell structure 24, and a side wall 42 surrounding the cell structure 24. In a particular embodiment, the frame 38 is made of a suitable polymer, such as for example polyvinyl chloride (PVC). Other suitable materials may be alternately be used.
In a particular embodiment, the fabric layer 34 is connected to the frame 38 around its perimeter, and the mesh layer 36 is connected to the fabric layer 34. Such connections may be done through any suitable type of adhesive or other fastening method, including, but not limited to, contact adhesive.
In the embodiment shown, the side wall 42 of the frame 38 is surrounded by adhesive tape 44 around its perimeter; the adhesive tape 44 may be, for example, a cloth-backed or scrim-backed pressure-sensitive tape such as duct tape. The tape 44, or a different type of tape, may also surround the side edges of the fragment-retaining layer 14 as shown.
A portion of the explosive force is mitigated as it passes through the mitigating layer 16. The fragment-retaining layer 14 is configured to resist to a remainder of the explosive force passing through the mitigating layer 16. The fragment-retaining layer 14 is made of a fragment-retaining material which minimizes shock wave transmission as well as retains fragments propagated by an explosion of a size corresponding to the explosive device(s) to be transported in the case 10. In a particular embodiment, the fragment-retaining layer 14 is made of polycarbonate, such as Lexan®, as this material has been proven to deform plastically to a great extent under explosive loading without rupture. Polycarbonate also features low acoustic impedance, which is desirable for shock wave attenuation. Alternatively, the fragment-retaining layer 14 can be made of a metal of similar properties and/or can comprise ballistic armor in order to protect the encased explosive devices from impinging projectiles or ammunition fragments.
The fragment-retaining layer 14 is thus connected to the outer surface of the outer wall 26 of the cell structure 24, as well as to the outer surface of the bottom wall 40 of the frame 38; the outer wall 40 of the frame 38 extends between the outer wall 26 of the cell structure 24 and the fragment-retaining layer 14 around the perimeter of the mitigating layer 16. The fragment-retaining layer 14 may be connected to the cell structure 24 through any suitable type of adhesive, including, but not limited to, double-sided adhesive tape.
It is understood that in cases where the blast containing panels 15 includes two mitigating layers 16, the elements of the second mitigating layer 16 on the other side of the fragment-retaining layer 14 have a mirror configuration with respect to the elements of the first mitigating layer 16.
In the embodiment shown, the body 18 includes an inspection port 54, formed by aligned holes through the outer shell 12 and adjacent blast containing panel 15. The port 54 facilitates examination or characterization by various means so that inspection devices such as optical and other electromagnetic imaging devices, chemical sensors, and radiation detection probes may be installed in appropriate locations. Alternatively, the port 54 may be provided with an appropriate nozzle to inject various kinds of agents, such as aqueous foams for blast effect mitigation or neutralizing of chemical or biological agents, or cleaning material for scrubbing radioactive dusts. The port 54, when not in use, is closed by an appropriate cover (not shown). Alternately, the port 54 can be omitted.
In the embodiment shown, the body 18 also includes at least one vent 52, which is defined by an aperture cut in one wall of the outer shell 12, in order to release hot blast gases. Preferably, the vent 52 is located near explosive devices within the case 10 and is vented in a direction away from a person carrying the case 10. The vent 52 is covered by the portion of the wall of the outer shell 12 removed to form the aperture (not shown), re-attached over the aperture in such a manner that the vent cover is easily dislodged under internal pressure.
Alternately, the vent 52 could be located in other locations, for example in corners of the outer shell 12. Also, alternate covers for the vent 52 include an elastic or flexible bag that expands under pressurization caused by an internal explosion. This expandable member may be substantially comprised of a fabric or plurality of fabric layers capable of catching debris and fragments from the detonation of a stored explosive device. Alternatively, the expandable member may be substantially comprised of a mesh that allows gradual release of internal gas, thereby reducing the loads imparted by the blast to the hinges 22 and lock(s) 24. Any combination of such components for vent covers can be made by an individual skilled in the design of blast protection devices, such as bellows-type components combined with mesh and elastic “balloon” components.
Although not shown, mountings or other provisions for cylindrical vessels, or other shapes of explosive devices, may be provided in the compartments. Straps or other similar components can be provided for additional restraint to the explosive devices within the compartments.
In a particular embodiment, wheels (not shown) are attached to the outer shell 12 to facilitate movement of the case 10 by hand or robot. The wheels may be integral to the outer shell 12, or be detachable to enable the wheel assembly to be removed when not needed. Alternatively, skids may be provided that also serve to facilitate movement.
Moreover, explosive devices or other items may be placed in protective cartons or wraps within the compartments to provide additional levels of protection. Such wraps and cartons may be substantially comprised of high-strength materials that resist bullets and ammunition fragments from penetrating.
The case 10 (as well as detachable wheels, if provided) may be provided with a bag enclosure that seals the case 10 when it is shut, to prevent release of dangerous materials to the external environment, for instance if the device within contains radioactive materials or potentially lethal pathogens. The bag enclosure may be part of the detachable wheeled or skid device, attached to the outer shell 12, or incorporated with the internal compartments or linings of the case 10. This bag enclosure may be coated or otherwise substantially comprised of materials that serve to neutralize the anticipated hazard.
The case 10 can also include shielding against the transmission of electromagnetic radiation or interference (EMI), including the effects of electromagnetic pulse (generally designated as EMP) when the case 10 is closed. The case 10, acting as a protection system, thus protects explosive devices kept therewithin from unintentional detonation or neutralization from radio waves or other electromagnetic events present outside the closed case 10. Provisions for electrical grounding may also be placed in suitable locations of the case 10 in order to prevent the buildup of static electricity.
Part or all of the outer shell 12 may utilize materials that facilitate external examination of the case contents, such as those permitting transmission therethrough of a desired portion of the electromagnetic spectrum. The fragment-retaining layer 14 and the mitigating layer 16 may be made of materials that are correspondingly similar.
The outer surface of the outer shell 12 and the surfaces of the blast containing panels 15 exposed within the enclosure, either alone or in combination, may be coated with fire-resistant materials in order to avoid ignition upon detonation of an encased explosive device. This is preferable when the case 10 is destined to contain energetic materials that may be capable of sustained burning with or without access to ambient air.
Should vessels or containers storing radioactive, chemical, or biological agents be placed within cases where explosive devices are also kept, internal protective components that prevent piercing the agent container may be integrated within the second enclosure.
The case 10 of the present invention thus minimizes the release of potentially hazardous phenomena under pressure above ambient to the environment external to it. Thus shock waves and pressurized gas leakage are mitigated to the degree desired by those who may be come into close proximity to the case 10 when explosive devices are contained therewithin.
The mitigating layer 16 preferably provides substantial cushioning in order to protect explosive devices placed within the case 10 from shock and impact. Thus, in a particular embodiment, the case 10 may be dropped, fall from a moving vehicle, stepped on, crushed by stacking with heavy objects, or struck by bullets with a reduced risk of explosion of the contained explosive devices or, in the case of an explosion, with limited risk of injury to people nearby. As it often is required to be carried by hand, the case 10 is preferably sized such as to be relatively light.
In a particular embodiment the case 10, sized accordingly, can safely contain a variety of small explosive devices, including, but not limited to, detonators, detonating cords, airbag inflators, fuses, small hand grenades, small anti-personnel mines, various recovered explosive devices, etc.
Although the case 10 has been described as a portable case, it is also considered to integrate the case in a rolling cart, in a vehicle, in a building, etc. Where the case 10 is integrated in an enclosure of an existing structure, the outer shell 12 can be omitted. The case integrated in a rolling cart could be used, for example, in an airplane, where the rolling cart would be of a serving-cart type, to be rolled in proximity of a potentially dangerous device found, so that the device could be place within the case 10 with minimal handling. The case integrated in a vehicle could be used, for example, in the cabin of a law enforcement vehicle, to transport small explosive devices destined to explode suspect devices, or to transport the suspect devices themselves away from the public.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.
