Thin shell pressure sensor
AssigneeExxon Production Research Company
InventorRobert B. Pan
Life of this patent
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Abstract
A thin shell pressure sensor for sensing in situ pressures in a medium in which the sensor is embedded is provided. The sensor operates on the principle that the membrane stresses near the apex of a thin shell under an external pressure load are proportional to the applied pressure. The constant of proportionality is dependent only on the geometry of the sensor.
Claims18
A thin shell pressure sensor for measuring in situ pressures in a medium in which the sensor is placed, said sensor comprising:
- a substantially flat base plate;
- a thin shell segment defining a curved surface bounded at a peripheral edge, said curved surface having an apex relatively distal on said curved surface from said peripheral edge, said thin shell segment attached to said base plate along said peripheral edge so as to form an enclosed chamber between said base plate and said thin shell segment, said thin shell segment being elastic and substantially rigid;
- and
- means for sensing membrane stresses in said thin shell segment at a position proximate said apex, said membrane stresses being caused by said in situ pressure of said medium.
A thin shell pressure sensor for measuring in situ pressures in a medium in which the sensor is embedded, said sensor comprising:
- a substantially flat base plate having an annular groove formed on one face thereof;
- a spherical thin shell segment having an apex, a peripheral edge and an annular shoulder formed along said peripheral edge, said annular shoulder matable with said annular groove so as to form an enclosed chamber between said base plate and said spherical thin shell segment;
- an annular retaining ring attached to said base plate by a plurality of screws, said annular retaining ring having an inside diameter slightly less than the outside diameter of said spherical shell segment so that said annular retaining ring overlaps the periphery of said spherical shell segment thereby firmly attaching said spherical shell segment to said base plate;
- a primary wire resistance strain gauge attached to the interior surface of said spherical shell segment at or near said apex of said spherical shell segment;
- a secondary, temperature compensating wire resistance strain gauge attached to the interior surface of said base plate;
- and
- means for detecting and recording the outputs of said primary and secondary strain gauges.
A thin shell pressure sensor for measuring in situ pressures in a medium in which the sensor is embedded, said sensor comprising:
- a substantially flat rectangular base plate having two longitudinal grooves formed on one face thereof, said grooves being substantially parallel to each other;
- a cylindrical thin shell segment having a longitudinal apex, two peripheral edges and two shoulders matable with said grooves formed along said peripheral edges, the length of said cylindrical thin shell segment being slightly longer than the length of said rectangular base plate so that both ends of said cylindrical segment extend a short distance beyond the ends of said base plate;
- two retaining bars attached to the longitudinal edges of said base plate by a plurality of screws so as to overlap the longitudinal peripheral edges of said cylindrical thin shell segment;
- two end caps attached to the longitudinal ends of said base plate by a second plurality of screws, said end caps having a curved groove matable with the longitudinal ends of said cylindrical thin shell segments formed on the inner face thereof;
- and
- one or more wire resistance strain gauges attached to the inner surface of said cylindrical thin shell segment, said strain gauges attached at or near the apex of said segment and oriented so as to measure circumferential strain.
Dependencies are inferred from the claim text.