Displacement sensor
AssigneeFisher-Rosemount Limited
InventorJames S. Johnston
Life of this patent
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Abstract
A sensor (1) for sensing the displacement of a body (12) comprises a deformable strip (2) enclosed in a chamber 3. The strip is constrained under longitudinal and transverse constraint such that end portions (9, 10) of the strip are parallel to a direction of movement of the body, the strip being locally deformed in the form of an S-bend. A magnet operable between the strip and the body varies the location of the S-bend along the length of the strip according to the position of the body. Optical or electronic sensors are provided for indicating the sensed position. The sensor may be used for sensing liquid levels or displacement of moving bodies such as valve elements particularly in hazardous environments including aircraft.
Claims22
A sensor for sensing the displacement of a body comprising a deformable strip, a rigid enclosure defining a chamber within which the strip is received and isolating the strip from contact with the body, constraining means operable to maintain the strip under longitudinal and transverse constraint such that first and second end portions of the strip extend substantially parallel to a longitudinal direction in which the body is movable relative to the sensor and locally deforming the strip in a transverse direction orthogonal to the first and second portions such that a deformed portion in the form of an S-bend integrally and unitarily connects the first and second end portions, and first magnetic means operable between the strip and the body to apply a magnetic force non-uniformly to the strip such that the location at which the strip is deformed to constitute the deformed portion is longitudinally variable in registration with a reference portion of the body whereby the longitudinal displacement of the deformed portion is representative of the displacement of the body.
Dependencies are inferred from the claim text.