GB1257786A - - Google Patents

Abstract

1,257,786. Seismic sources. INSTITUT FRANCAIS DU PETROLE DES CARBURANTS ET LUBRIFIANTS. 13 Dec., 1968 [14 Dec., 1967], No. 59489/68. Heading H4D. [Also in Division H1] An underwater seismic wave generating device comprises in a housing a pair of spaced electrodes 1a and 5, a burner 1 adapted to be connected to a source of inflammable gaseous mixture and constructed and disposed to form an ionized conducting flame filling the gap between the electrodes, the electrodes being spaced apart by such a distance that for a predetermined voltage no discharge could occur between them in the absence of a flame, and means to cause a transfer of electric energy between the electrodes at said voltage when the ionized conducting flame fills said gap whereby the ionized conducting flame is heated and expanded sufficiently rapidly to produce one or a succession of seismic waves in the water. A tungsten tube 1 with a nozzle 1a acting as both electrode and burner is separated by an insulator 2 from a conductive sleeve 3 with bars 3a connected to a ring 4 supporting a grid electrode 5. Insulating coatings 6 are provided on the tube 1, sleeve 3, bars 3a and cable 7. The tube 1 and cable 7 are connected across a bank of capacitors. The gaseous mixture may be seeded with powders of fine metallic particles to promote ionization. In alternative embodiments two electrode-burners are mounted opposite teeth projecting from a grid electrode (Fig. 5, not shown), or the gases are mixed in a combustion chamber and pass through an aperture in a graphite diaphragm forming one electrode (Fig. 6, not shown). In all embodiments the electrodes and burner may be mounted in a streamlined hull provided with stabilizing pins and having a portion forming a Venturi nozzle to direct water around the gas nozzle.