Sonic logging apparatus

Claim 1

Acoustical logging apparatus comprising; an elongated housing adapted to be lowered into a well; an acoustical signal receiver carried by said housing adjacent one end thereof to establish electrical signals representative of acoustical signals received by said receiver; a source of D.C. potential carried by said housing adjacent the second end thereof; first and second electrical pulse generators carried by said housing adjacent the second end thereof to establish electrical pulses at different times; first and second acoustical signal generators carried by said housing in spaced relationship with one another between the first and second ends of said housing, each of said signal generators comprising an annular core of magnetostrictive material axially aligned with said housing, a toroidal coil wound on said core, a capacitor mounted immediately adjacent said core, and a controlled rectifier mounted immediately adjacent said core; first circuit means connecting said source of potential to the capacitor of said first signal generator to charge same; second circuit means connecting said first pulse generator to the rectifier of said first signal generator to cause said rectifier to conduct; third circuit means connecting the capacitor and the rectifier in circuit with the coil of said first signal generator to discharge said capacitor through said coil when a pulse is applied to said rectifier from said first pulse generator; fourth circuit means connecting said source of potential to the capacitor of said second signal generator to charge same, said fourth circuit means extending past and being positioned externally of the coil of said first signal generator; fifth circuit means connecting said second pulse generator to the rectifier of said second signal generator to cause said rectifier to conduct, said fifth circuit means extending past and being positioned externally of the coil of said first signal generator; sixth circuit means connecting the capacitor and the rectifier of said second signal generator in circuit with the coil of said second signal generator to discharge said capacitor through said coil when a pulse is applied to said rectifier from said second signal generator; signal receiving means carried by said housing adjacent the second end thereof to receive electrical signals from said receiver; and seventh circuit means extending from said receiver to said signal receiving means to transmit electrical signals from said receiver to said signal receiving means, said seventh circuit means extending past and being positioned externally of the coils of said signal generators.