Abstract: A system for using a ferrite element to convert RF energy into heat consists only of the ferrite element, an RF generator and a cable connecting the ferrite element to the RF generator. No external impedance matching mechanism is needed, and the preferred form of the ferrite has a Curie temperature in excess of 150.degree. C., and has a lower cutoff frequency of about 10 KHz. The specific best mode ferrite element includes a formulation of MnO.sub.0.45 Zn.sub.0.3 FeO.sub.0.25 Fe.sub.2 O.sub.4. One use of the circuit is in the mining industry.

Abstract: The precision ignition device disclosed in U.S. Pat. No. 4,708,060 is combined with the device disclosed in U.S. Pat. No. 5,036,768, and U.S. Ser. No. 07/584,045 to provide accurate control over the ignition of an EED while also protecting that EED from inadvertent firing caused by exposure to extraneous electricity, such as RF energy or electrostatic energy. The combined device can be connected to a source of power and/or to an external sequential timer for further control over the firing process. A method of fabricating the means for protecting the EED from inadvertent extraneous electricity induced firing is also disclosed.

Abstract: A device for preventing an electroexplosive device from inadvertent RF energy or electrostatic energy induced firing, even if that device is exposed to high RF power levels or high RF frequencies or to high electrostatic potentials, includes an impedance element in the firing input line between a source of dc power and a bridgewire which has an impedance that exceeds an impedance between the input leads and ground. When RF energy levels and frequencies exceed certain values, arcing occurs between one input lead and the other or between the input leads and a conductive case to cause energy to flow to the conductive case instead of to the bridgewire. One form of the device includes a Ferrite element in electrical and thermal contact with both of the firing input leads and with the thermally and electrically conductive case. The Ferrite element has a dc resistance in excess of the dc resistance of the bridgewire so short circuiting the firing current does not occur.

Abstract: A device for preventing energy associated with nearby lightning strikes, electrostatic energy, and/or RF energy from damaging or inadvertently operating or actuating electronic equipment, such as an EED electrical initiation element, includes a bipartite faraday shield. One wall of the bipartite faraday shield is formed of a ferrite element such as disclosed in U.S. Pat. No. 5,036,768 and application Ser. No. 07/584,045. In some cases, the ferrite element can be doped with calcium oxide. The preferred doping range is between 1 and 20 ppm. A specific embodiment of the bipartite faraday shield includes an open-ended metal case with the ferrite device closing the open end of the case.

Abstract: An implantable prosthesis, such as an artificial cardiac pacer, or the like, is protected from misoperation caused by RF energy and/or electrostatic energy incident thereon by a protective device attached to the lead wire connecting the device to tissue stimulating electrodes or other such electrodes mounted in a patient. The protective device is the device disclosed in U.S. patent application Ser. Nos. 07/794,125, 07/584,045 and 07/866,512. The protective device includes a Ferrite body electrically and thermally connected to the lead wire and to a ground element, such as the housing for the prosthetic device. The Ferrite body, in conjunction with the lead and the ground element, has an impedance that exceeds the impedance established between the lead wire and ground when the device is exposed to RF energy.

Abstract: An attenuator for dissipating electromagnetic energy and equalizing electrostatic energy is formed of a lossy ferrite material having an electrical resistance in a range of about 3,000 to 50,000 ohms. A conductor passes through the material and thence to a bridgewire to supply a firing charge to heat the bridgewire. In one embodiment of the invention, the attenuator is mounted within an electrically and thermally conductive housing, which will dissipate heat and equalize electromagnetic energy which may be induced in the conductor. A capacitive effect may be imparted by the orientation of the conductor as it passes through the ferrite. The capacitive effect is produced in winding the conductor parallel to the metal housing, and parallel to any other conductor passing through the ferrite. In the preferred form, the conductors are wound through the ferrite in a spiral pattern parallel to the conductor housing.

Abstract: An RF attenuator for attenuating RF signals in a lead particularly for prcting against unintentional detonation of electrically initiated ammunition is presented. A firing lead is embedded in a body of ferrite material. The firing lead is formed in a planar spiral configuration with reversals of direction.

Abstract: A disposable EOD dearmer (10) includes an propellant charge (36) permanen affixed to a tubular body (14) for propelling a dearmer slug (40) against a dud casing (12). The pressure versus time characteristic (60, 70) of the charge can be selected to provide a preselected velocity for the slug at impact with the casing, and the initial position (60', 70") of the slug can be selected to provide a preselected delay between ignition of the charge and impact between the slug and the casing.

Abstract: A self contained jet perforator torch (10) for defining large holes (H) in workpiece (W) such as a large bomb, includes a plurality of ports (68) fluidically connecting a combustion chamber with a slot-like chamber (62). The ports and the slot-like chamber extend at an angle with respect to the longitudinal centerline of the torch whereby fluid exiting the torch contacts a workpiece at an angle (I) with a normal (N) extending from the workpiece.

Abstract: A composition for a cutting touch for quickly breaching a munition casing d burning out the energetic material therein consists essentially from about 15 to about 20 weight percent of aluminum, from about 5 to about 10 weight percent of the copolymer of vinylidene fluoride and hexafluoropropylene, up to about 0.6 weight percent of graphite and the remainder of ferric oxide.

Abstract: A broad band attenuator having a ferrite material for absorption of stray electromagnetic radiation minimizes the unintentional initiation of electroexplosive devices. In one embodiment, each input lead of a detonator passes through a ferrite choke core in contact with the metallic casing that houses the detonator. A printed circuit tape between the input leads and the casing provides electrostatic protection, and heat generated by the ferrite choke core is removed by radiation from the metal casing.