HYDROSTATIC PRESSURE MEASUREMENT METHOD AND FIBRE OPTIC HYDROSTATIC PRESSURE SENSOR Russian patent published in 2024 - IPC G01L1/24 

FIELD: hydrostatic pressure sensors; fibre-optic pressure sensors.

SUBSTANCE: method for measuring hydrostatic pressure with a fibre-optic sensor involves introducing a sensitive element of a fibre-optic sensor of linearly polarized radiation into a birefringent fibre and recording changes in the introduced radiation that occur in the birefringent optical fibre under the influence of hydrostatic pressure. The change in the power of optical radiation in polarization modes in the optical fibre is recorded, based on the value of which, using the parameters of the birefringent fibre and optical radiation, the value of the desired hydrostatic pressure is calculated. A fibre-optic hydrostatic pressure sensor contains an optically connected radiation source and a sensitive element connected to a measuring installation, including an optical fibre bonded to a cylindrical body; metal cylindrical rods are continuously distributed and secured along the surface of the hollow cylindrical body of the sensitive element, on which a birefringent optical fibre is wound. Moreover, the cylindrical rods are distributed over the surface of the hollow cylindrical body of the sensing element with a given periodicity with a period T equal to the beat length Λ of the birefringent fibre of the sensing element, on top of which a membrane made of hard and elastic material is tightly placed and hermetically secured around said fibre. The measuring installation includes a polarization divider connected to two photodetectors, and the birefringent optical fibre of the sensitive element is connected to a source of linearly polarized radiation, and through the polarization divider of the measuring installation to photodetectors. The proposed solutions provide an accuracy of 0.5 atm of the measured pressure and increase the range of the measured pressure to 200 atm while simplifying the measurement method.

EFFECT: expansion of the range of measured pressure by increasing the points at which the coupling of polarization modes occurs in the birefringent optical fibre of the sensing element, increasing the safety factor of the sensing element and simplifying the method.

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