Geophone system
OwnerJacobus W. P. van der Poelinventor
Life of this patent
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Abstract
A geophone system for measuring mechanical vibrations such as seismic waves include a mechanical transducer with an electronic processing circuit. The mechanical transducer includes an inertial mass adapted to be excited by an input acceleration signal and by a force transducer. The excitation is detected by a sensor element and the processing circuits of the geophones control the force transducer and are connected with a central station via a transmission line.
Claims12
A geophone system, comprising a plurality of geophones each consisting of a mechanical transducer and an electronic processing circuit, the mechanical transducer comprising an inertial mass and a force transducer, the inertial mass being adapted to be excited by an input acceleration signal and by the force transducer, the excitation being detected by a sensor element, said force transducer being controlled by the electronic processing circuit, the processing circuits of said geophones being connected with a central station by means of a transmission line element, characterized in that the sensor element detects the velocity of the inertial mass and controls an analog/digital converter by means of an amplifier with a very high gain factor, in that the output of the analog/digital converter is connected with the input of a digital/analog converter and in that the output of this digital/analog converter controls the force transducer.
A transducer for detecting mechanical vibrations, in which each mechanical transducer comprises a coaxial permanent magnet assembly and a coaxial coil assembly comprising a sensing coil and a drive coil which are arranged coaxially in a tubular outer pole shoe, one assembly being movable and the other one being stationary, springs being provided between both assemblies, characterized in that the permanent magnet assembly consists of a permanent magnet which, at both sides, is provided with two inner pole shoes, the drive coil being arranged in the air-gap between one of the inner pole shoes and the outer pole shoe, and the sensing coil being provided in the air-gap between the other inner pole shoe and the outer pole shoe, a compensation coil being arranged outside the magnetic field of the magnet and inside the outer pole shoe, all this in such a manner that the induction voltage induced as a consequence of the alternating flux produced by the drive coil in the compensation coil is substantially equal to the induction voltage induced as a consequence of the alternating flux in the sensing coil.
Dependencies are inferred from the claim text.