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US 4,391,195 AGranted
Detonation of explosive charges and equipment therefor
OwnerPeter C. Shanninventor
Life of this patent
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OwnerPeter C. Shanninventor
Estimating the term…
Explosive charges for blasting purposes are actuated by a system of optical fibres supplied with energy from a laser. The laser energy output is substantially in excess of that required for detonation and does not need to be preserved in coherent form, enabling transmission to be via optical fibres and connecting and/or distributing devices of quality or properties unsuitable for data transmission. Simple intermittently driven mechanical arrangements can be used for the sequential firing of a set of charges. Connection to detonators can be by expendable lengths of fibre fed from a main optical channel via simple, economic, plug-and-socket arrangements. The detonators, or components containing flashing composition coating the end of the expendable fibre, may be supplied with an attached fibre ready connected to an expendable optical plug. The connection of the laser with an optical cable, terminating in optical socket arrangements may be by a simple lens arrangement, uneven distribution of energy between the individual fibres being well tolerated.
A system for connecting a set of explosive charges with a laser for detonation by optical energy from the laser which comprises an input for optical energy produced by the laser, a set of optical fibres for connection one with each of the charges and distributor means for distributing optical energy from the input to the fibres of said set, said fibres having longitudinal axes and said distributor means being operable to receive energy from the laser and to direct a part of the received energy into the fibres and to direct the remainder of the received energy to waste, at least a substantial proportion of the part directed into the fibres being directed non-axially so that the propagation of said at least a substantial proportion through the fibres is by zigzag paths.
A detonating device for detonating an explosive charge by energy from a laser, said device comprising a length of optical fibre which terminates in a transverse end face and adjacent to the end face, a body of a flashing composition in the form of an active material and a resinous binder, said active material being selected from the group of substances consisting of silver azide, the mono- and di-nitro resorcinols and their salts, and the mono- and di-nitroso resorcinols and their salts and mixtures of at lesat two of these substances, said composition being bound into a coherent form by said binder.
A method of detonating a series of explosive charges by means of a laser which comprises fitting the charges with detonators each of which terminates one end of a length of optical fibre and is constituted and arranged to be actuated by optical energy received from the laser via said length, connecting the opposite end of the first of said lengths with an optical supply line leading from said laser and having an attenuation per unit length for the laser energy which is substantially smaller than that of the said length, passing energy from the laser to detonate the charge fitted with the detonator which terminates said first of said lengths, and subsequently detonating the remaining charges in turn by connecting the remainder of the said lengths with said supply line and passing energy from the laser, the connection of the said lengths with the supply line being effected by inter-engaging connecting components.
A system for detonating a set of spaced-apart explosive charges which comprises an optical cable having a number of optical fibres extending through the cable from an input to the cable to an output from the cable and diverging from one another at the output for connection with separate ones of the spaced-apart charges, the fibres at the input having input ends positioned together in a reception zone, a laser apparatus for providing a laser beam distributed over the reception zone, the arrangement being such that the part of the laser energy of the beam intercepted by the input end of each fibre in the reception zone is sufficient for the detonation of at least one of such charges and, interconnecting the laser apparatus and the cable, a pair of complementary members of the plug and socket type, one mounted on the laser apparatus and the other on the cable.
Dependencies are inferred from the claim text.