Highly sensitive accelerometer
AssigneeWeatherford/Lamb, Inc.
InventorsSverre Knudsen, Arne Berg, James R. Dunphy, Daniel Woo
Life of this patent
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Abstract
A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers maybe multiplexed using WDM or similar methods.
Claims21
A highly sensitive linear accelerometer for sensing acceleration in a predetermined direction, said accelerometer comprising:
- a rigid housing;
- a mass;
- at least two elastic support members axially aligned in said predetermined direction and attached to opposite ends of said housing and further attached to said mass, said elastic support members suspending said mass within said housing;
- and
- at least a portion of one of said elastic support members comprising a transducer capable of measuring a displacement of said mass within said housing in response to an acceleration along said predetermined direction.
A highly sensitive linear accelerometer for sensing acceleration in a predetermined direction, said accelerometer comprising:
- a rigid housing;
- a mass having an elongated body and a first and second rounded ends;
- a first fixed mandrel and a second fixed mandrel, both rigidly attached to said housing a predetermined distance apart;
- a first pair of elastic support members axially aligned in said predetermined direction and wrapped around said first fixed mandrel and said first rounded end in a continuous fashion;
- a second pair elastic support members axially aligned in said predetermined direction and wrapped around said second fixed mandrel and said second rounded end in a continuous fashion;
- at least a portion of one of said elastic support members comprising a transducer capable of measuring a displacement of said mass within said housing in response to an acceleration along said predetermined direction;
- and
- a pair of axial alignment assemblies attached to said mass limiting movement of said mass in a direction perpendicular to said predetermined direction.
An apparatus for vertical seismic profiling of the earth having an x-direction, a y-direction and a z-direction orthogonal to each other, said apparatus comprising:
- an optical fiber transmission cable;
- and
- a plurality of linear accelerometers coupled to the earth and in optical communication with said optical fiber transmission cable and positioned in each of the three orthogonal directions, each said linear accelerometer comprising highly sensitive accelerometer for sensing acceleration in a predetermined one of said directions, said accelerometer comprising:
- a rigid housing;
- a mass;
- and
- at least two elastic support members comprised of optical fiber axially aligned in said predetermined direction and attached to opposite ends of said housing and further attached to said mass, said elastic support members suspending said mass within said housing wherein at least a portion of one of said elastic support members comprises a transducer capable of measuring a displacement of said mass within said housing in response to an acceleration along said predetermined direction and providing a respective sensing light signal indicative of static and dynamic forces at a respective accelerometer location.
Dependencies are inferred from the claim text.