Embodiments of the present disclosure relate generally to initiation devices and systems. In particular, the present disclosure relate generally relates to initiation devices for initiation of energetic materials, systems including initiation devices, and methods of igniting devices including one or more energetic materials using initiation devices.
Energetic materials may be initiated by initiation or detonation devices. Due to the destructive nature of energetic materials, such as explosives, these devices may incorporate various safety features to avoid premature initiated of the energetic materials. Energetic materials may be ignited in several different ways. Typically, energetic materials have been ignited by flame ignition (e.g., fuzes or ignition of a priming explosive), impact (which often ignites a priming explosive), chemical interaction (e.g., contact with a reactive or activating fluid), or electrical ignition. Electrical ignition may occur in two distinct ways, as by ignition of a priming material (e.g., electrically ignited blasting cap or priming material) or by direct energizing of an explosive mass by electrical power.
Remote activation systems for initiation of energetic materials have been used widely in the field of military and industrial demolition applications. Control systems (e.g., a fireset) may be used to generate an electrical impulse for initiating an energetic material. For example, a blasting cap used in conjunction with an explosive charge (e.g., pentaerythritol tetranitrate (PETN), C4, etc.) can be electrically connected to output terminals of the initiation device using electrical conductors. In many instances, the initiation assembly including an initiation device and associated control system is sensitive to electrical conditions, such as voltage and current transients (e.g., electrostatic discharge (ESD)) and electromagnetic interference (EMI). As a result of this sensitivity, premature initiation of the explosive charge has been known to occur with unacceptable frequency. The results of premature initiation can include unintended damage and/or unintended personal injury or death.
The use of initiation devices with energetic materials, such as non-high explosive materials (e.g., low explosives that decompose primarily through deflagration), may present further problems as non-high explosive materials may be inadvertently ignited by the heating and/or combustion of the initiation device. For example, voltage and current transients in the initiation device and associated control system may cause the unintended heating and combustion of components of the initiation device (e.g., an exploding bridge wire (EBW)). Such unintended heating and combustion may result in the premature initiation of the non-high explosive materials associated with the initiation device.
In some embodiments, the present disclosure includes an initiation device. The initiation device includes at least one substrate configured to electrically couple with a control system and an initiation element configured to ignite an energetic material. The initiation element is positioned on a first side of the at least one substrate. The initiation device further includes a spark gap electrically coupled to the initiation element. The spark gap is positioned on a second side of the at least one substrate. The initiation device is configured such that a current resulting from a voltage supplied to the initiation device from the control system passes through the spark gap before initiating the initiation element.
In additional embodiments, the present disclosure includes an initiation device. The initiation device includes a plurality of substrates configured to electrically couple with a control system. At least one substrate of the plurality of substrates is electrically connected to at least one adjacent substrate of the plurality of substrates with at least one via extending through the at least one substrate. The initiation device further includes an initiation element configured to ignite an energetic material and positioned on one substrate of the plurality of substrates and a spark gap electrically coupled to the initiation element and positioned on another substrate of the plurality of substrates. The initiation element is electrically connected to the spark gap with the at least one via.
In yet additional embodiments, the present disclosure includes an initiation system. The initiation system includes a control system and at least one initiation device configured to be electrically connected to the control system.
In yet additional embodiments, the present disclosure includes a method of igniting energetic material. The method comprises supplying a voltage to an initiation device, passing a current resulting from the voltage through a spark gap formed on at least one substrate of the initiation device, passing the current through at least one via formed through the at least one substrate of the initiation device, and passing the current through an explosive bridge wire of the initiation device to ignite the explosive bridge wire.
While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as embodiments of the present disclosure, the advantages of embodiments of the disclosure may be more readily ascertained from the following description of embodiments of the disclosure when read in conjunction with the accompanying drawings in which:
The illustrations presented herein are not meant to be actual views of any particular material, device, apparatus, system, or method, but are merely idealized representations which are employed to describe embodiments of the present disclosure. Additionally, elements common between figures may retain the same numerical designation for convenience and clarity.
The initiation element 108 is configured to ignite one or more of energetic materials (e.g., explosive materials, reactive materials, combustible materials, incendiary materials, and combinations thereof). For example, the exploding bridge wire 108 may be configured to ignite an explosive material, such as, for example, a non-high explosive material or low explosive material that decomposes primarily through deflagration (e.g., a subsonic combustion propagated, for example, through thermal conductivity rather than a supersonic combustion (i.e., detonation)). For example, the low explosive material may include, but is not limited to, pyrotechnic compositions (e.g., thermites, flares, fireworks, etc.), propellants, incendiary materials or devices, and gunpowders. In other embodiments, the initiation element 108 may be configured to ignite other energetic materials that decompose by differing mechanisms (e.g., detonation).
The circuit 106 includes an electrical feature (e.g., a spark gap 110) coupled to the initiation element 108 for regulating the amount of one or more of voltage and current that is passed through the circuit 106. For example, the spark gap 110 may be electrically coupled to (e.g., in series with) the initiation element 108. The spark gap 110 requires a threshold voltage to be supplied to the circuit 106 before an electric spark (e.g., an electric arc) will pass between conductors of the spark gap 110 that are separated by a fluid. As depicted, the voltage may be provided by leads (e.g., a first lead 112 and a second lead 114 that have an electrical potential therebetween such as, for example, a positive lead and a negative lead) that are electrically coupled to the control system 104. In some embodiments, at least a portion of the initiation device 102 may be sealed (e.g., hermetically sealed) such that the gap of the spark gap 110 may comprise a gas different than the atmosphere in which the initiation device 102 is placed such as, for example, an inert gas (e.g., argon). In other embodiments, the gap of the spark gap 110 may comprise atmospheric air.
When the voltage provided from lead 112 is greater than a threshold voltage, current may pass through spark gap 110 and the initiation element 108 to lead 114. In some embodiments, the threshold voltage may be between 500 and 2000 volts (e.g., at least 500 volts, at least 750 volts, at least 1000 volts, at least 1500 volts).
In some embodiments, the circuit 106 may include resistor 115 (e.g., a 10 MΩ 100 MΩ resistor) positioned between the leads 112, 114 (e.g., in parallel with one or more of the initiation element 108 and the spark gap 110). Resistor 115 may provide a closed circuit loop (e.g., as opposed to the parallel open circuit loop including the spark gap 110). Such a closed circuit loop may be required by the control system 104 in order to initiate the initiation device 102.
The control system 104 may include any system, assembly, or device capable of supplying an electrical signal (e.g., voltage) to the initiation device 102. For example, the control system 104 may comprise an electric system capable of supplying a signal to the initiation device 102 in order to initiate the initiation element 108 of the initiation device 102. In some embodiments, the control system 104 may be remotely controlled enabling a user to remotely initiate the initiation device 102 with the control system 104.
In some embodiments, the control system 104 may include a safe and arm device (also termed a SAD or an S&A). Safe and arm devices may include an assembly or system that mechanically and/or electrically (i.e., electronic safe and arm devices (ESADs)) interrupts a firing train and prevents inadvertent functioning of an initiation assembly. For example, an ESAD may isolate electronic components between a power source and a detonator to inhibit inadvertent firing of the system. Such a control system 104 including an ESAD may supply a voltage to the initiation device 102 only when it is desired to ignite the initiation device 102.
Lead 212 and via 216 may be electrically connected to conductive material on the first side 201 of the substrate 204 (e.g., first conductive trace 220). The first conductive trace 220 may be electrically connected to a first portion of an initiation element 208 (e.g., a first end of an exploding bridge wire (EBW)). A second portion of the initiation element 208 (e.g., a second, opposing end of an exploding bridge wire (EBW)) may be electrically connected to conductive material on the first side 201 of the substrate 204 (e.g., second conductive trace 222). The second conductive trace 222 may be electrically connected to conductive material (e.g., third conductive trace 226) on the second side 203 of the substrate 204. For example, one or more vias 224 may extend through the substrate 204 to electrically connect the second conductive trace 222 to the third conductive trace 222).
Lead 214 and via 218 may be electrically connected to conductive material on the second side 203 of the substrate 204 (e.g., fourth conductive trace 230). A spark gap 210 between the third conductive trace 226 and the fourth conductive trace 230 may provide a selective electrical connection between the third conductive trace 226 and the fourth conductive trace 230 (e.g., a connection made only when the voltage supplied by the leads 212, 214 exceeds a threshold amount). In other words, lead 212 is permanently electrically connected (e.g., constantly connected) to the first portion of the initiation element 208 and lead 214 is selectively electrically connected (e.g., intermittently connected) to the second portion of the initiation element 208 via the spark gap 210.
As discussed above in relation to
Referring to
As depicted, the initiation device 302 includes a first substrate 350 for connecting (e.g., coupling) to the leads 312, 314 and including a spark gap 310. The initiation device 302 includes a second substrate 352 positioned adjacent the first substrate 350 and having an aperture 360 in the second substrate 352 for forming a cavity about the gap of the spark gap 310. For example, as discussed above, the aperture 360 may be sealed within the housing 304 such that a selected fluid (e.g., gas) may be provided in the gap of the spark gap 310. The initiation device 302 includes a third substrate 354 positioned adjacent the second substrate 352 having an initiation element 308 (e.g., an exploding bridge wire (EBW)).
The initiation device 302 includes one or more materials positioned proximate the initiation element 308 on the third substrate 354 that are to be initiated by (e.g., ignited by) the initiation element 308. For example, a first reactive material 356 (e.g., a thermite) may be positioned adjacent to (e.g., in contact with) the initiation element 308 and a second reactive material 358 (e.g., a thermite that is less reactive than the thermite of the first reactive material 356) may be positioned adjacent to (e.g., in contact with) the first reactive material 356. In some embodiments, the second reactive material 358 may have an aperture 362 formed in the second reactive material 358 (e.g., along the longitudinal axis L302 of the initiation device 302). During decomposition (e.g., combustion) of the second reactive material 358, the aperture 362 may form a jet of combusting material that may exit the housing 304 (e.g., through an open end 364 of the housing 304) to assist in the ignition of another material (e.g., an energetic material such as a low explosive material) that the initiation device 302 is intended to initiate.
It is noted that, in some embodiments, the initiation device 202 may include a housing and one or more energetic materials disposed therein in a manner similar to the initiation device 302.
Lead 312 (
Lead 314 and via 318 may be electrically connected to conductive material on the first side 301 of the first substrate 350 (e.g., third conductive trace 324). The third conductive trace 324 and the combination of the first conductive trace 320 and the second conductive trace 322 may each extend across the first side 301 of the first substrate 350 to provide an offset between the leads 312, 314 and initiation element 308 (
As discussed above in relation to
Vias 370, 372 may be electrically connected to the second conductive trace 322 and the third conductive trace 324 on the first side 351 of the first substrate 350 (
As mentioned above, the aperture 360 in the second substrate 352 may form a cavity about the gap of the spark gap 310 (
Vias 374, 376 may be electrically connected to the vias 370, 372 of the second substrate 352 (
In some embodiments, the third substrate 354 may include conductive materials 382 that are electrically connected to the vias 366, 368 of the second substrate 352 (
Referring to
Referring the
By way of further example, referring to
As discussed above, the voltage supplied by control system 104 may initiate the initiation element 108, 208, 308. For example, the voltage may combust the initiation element 108, 208, 308 such as, for example, an exploding bridge wire (EBW). The energy (e.g., thermal energy) from the combustion of the exploding bridge wire may initiate (e.g., ignite) a material positioned proximate the exploding bridge wire. For example, as shown in
It is noted that initiation devices and control systems may be utilized in numerous applications such as, for example, military, mining and drilling operations, demolition, and any suitable pyrotechnic application.
Embodiments of the present disclosure may be particularly useful in providing initiation devices having relatively greater reliability, safety, and compatibility as compared to conventional initiation devices employing similar components. For example, embodiments of initiation devices as disclosed herein may be particularly useful in igniting materials that decompose primarily through deflagration rather than detonation. In some embodiments, the initiation device may output primarily thermal energy with little to no shock wave and a minimal pressure wave.
Furthermore, embodiments of initiation devices as disclosed herein may also provide an initiation device that protect against inadvertent firing due to low voltage, high current stray voltage initiation and high voltage, low current stray voltage initiation. For example, the spark gap of the initiation device protects against low voltage, high current stray voltage initiation as the spark gap is selected to only pass voltage to the initiation element at a voltage higher than a threshold voltage. The exploding bridge wire of the initiation device protects against high voltage, low current stray voltage initiation as the exploding bridge wire will not initiate explosive, combustible, or reactive material positioned proximate the exploding bridge wire as the exploding bridge wire will not provide sufficient heating until the current reaches a threshold value.
While the present disclosure may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure includes all modifications, equivalents, legal equivalents, and alternatives falling within the scope of the disclosure as defined by the following appended claims.
This invention was made with government support under Contract No. DE-AC07-05ID14517 awarded by the United States Department of Energy. The government has certain rights in the invention.