GB1156579A - Metallic Path Acoustical Seismic Source - Google Patents

Abstract

1,156,579. Generating seismic energy. TELEDYNE INDUSTRIES Inc. 17 Aug., 1967 [19 Oct., 1966], No. 37864/67. Heading H4D. In an arrangement for generating acoustical inpulses under water (e.g. for seismic surveying) by electrically " exploding " a wire bridging spaced underwater contacts the wire is supplied to the contacts via tubular means in which it is entrained in a flowing fluid. Thus the wire 18 (Fig. 2) carried by reel 16 is conveyed to a first electrode 12 via tubular means 20 in which it is entrained in a flow of water produced by a pump 32. Electrode 12 is provided with a bore 12a (Fig. 3) through which the wire is carried towards the second electrode 14 by the water flow the latter electrode being streamlined so that the flow causes the wire to " hug " its surface. The electrode structure (Fig. 3) is towed behind a vessel V (Fig. 1) by a cable C comprising the tubular means 20 and the electrical conductors 22, 24 which connect the electrodes to an electrical energy source 20 via trigger operated switch means 10. In operation a timer controller K releases brake 42 to allow a length of wire sufficient to bridge the contacts to be carried into the required position by the water flow, pump 32 being continuously driven by (internal combustion engine) motor 34. The brake then arrests reel 16 and causes trigger T to close contacts 10 so that the resulting " explosion " (vaporization) of the wire by the flow of current from source S produces a (steam) bubble the size and rate of change of which determine the energy of the resulting acoustical impulse.