Method and apparatus for the acquisition of seismic movements
OwnerKlaus Schleisiek, Mark Bolduaninventors
Life of this patent
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Abstract
The method and the apparatus disclosed serve to acquire seismic induced movements. A coil and a permanent magnet are contained in an enclosure and the seismic movements induce a relative movement between said coil and said magnet. The current induced into the coil is appraised as a measure of said seismic movement. The position of the coil in relation to the permanent magnet is monitored by a position sensor. A closed loop control generates a current that is fed into the coil so that the coil settles at a given neutral position relative to the permanent magnet.
Claims17
A method for acquiring seismic movements in at least one direction, the method comprising providing a seismic sensor comprising a coil and a permanent magnet (8) capable of performing relative movements against each other inside an enclosure, measuring the current induced in the coil as an electrical representation of the seismic movement, wherein additional position detector means inside the enclosure measure the relative position of the coil with respect to the permanent magnet and additional control means feed a compensation current into said coil so that the coil recaptures a predetermined position with respect to the permanent magnet, further comprising using an integrator of the control means for increasing or decreasing the compensation current until the coil has reached a predetermined position.
An apparatus for the acquisition of seismic movements comprising at least one coil (2) and one permanent magnet (8) inside an enclosure (7), in which said permanent magnet is rigidly fixed to said enclosure and said coil can move along its longitudinal axis relative to said permanent magnet and said enclosure and in which said coil is connected to measurement means to measure the electrical current flowing through the coil, wherein said coil is connected to a feedback arrangement consisting of a control circuit present for a current flowing through the coil at least temporarily and the control also being connected to a position sensor acquiring the momentary position of said coil relative to said permanent magnet, wherein the control means includes an integrator for increasing or decreasing the compensation current until the coil has reached a predetermined position.
Dependencies are inferred from the claim text.