The present invention relates to detonators, and more particularly, to non-energetics-based detonators, detonator systems using non-energetics based detonators and methods of detonating explosives.
In various industries, such as mining, construction and other earth moving operations, it is common practice to utilize detonators to initiate explosives loaded into drilled blast holes for the purpose of breaking rock. For instance, commercial electric and electronic detonators are conventionally implemented as hot wire igniters that include a fuse head as the initiating mechanism to initiate a corresponding explosive. Such hot wire igniters operate by delivering a low voltage electrical pulse to the fuse head, causing the fuse head to heat up. Heat from the fuse head, generated in response to the low voltage electrical pulse, initiates a primary explosive, e.g., lead azide, which, in turn, initiates a secondary explosive output pellet, such as pentaerythritol tetranitrate (PETN) at an output end of the detonator. However, conventional hot wire igniters must rely on an extremely sensitive primary explosive to transition the detonation process from the fuse head to the corresponding explosive output pellet. Moreover, it is possible that the voltage and power requirements to function this type of conventional hot wire igniter may be encountered from inadvertent sources like static, stray currents and radio frequency (RF) energy.
Another exemplary detonator type is referred to as an exploding bridgewire detonator (EBW). The EBW includes a short length of small diameter wire that functions as a bridge. In use, explosive material beginning at a contact interface with the bridge wire transitions from a low density secondary explosive pellet to a high density secondary explosive pellet at the output end of the detonator. To initiate a detonation event, a high voltage pulse is applied in an extremely short duration across the bridge wire causing the small diameter wire to explode. The shockwave created from the bridge wire's fast vaporization initiates the low density secondary explosive pellet, such as PETN, which in turn initiates the high density secondary explosive pellet such as cyclotrimethylene trinitramine (RDX), at the output end of the EBW.
Yet another exemplary detonator type is referred to as an exploding foil initiator (EFI). A conventional EFI includes a thin metal foil having a defined narrow section. A polymer film layer is provided over the metal foil. To initiate a detonation event, a high voltage, very short pulse of energy is applied across the metal foil to cause the narrow section of the metal foil to vaporize. As the narrow section of the metal foil vaporizes, plasma is formed as the vaporized metal cannot expand beyond the polymer film layer. The pressure created as a result of this vaporization action builds until the polymer film layer is compromised, thus triggering a shock wave that initiates the detonation a connected explosive device.