Apparatus configured to detect a physical quantity of a flowing fluid, and a respective method
AssigneeNederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
InventorWouter Schiferli
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Abstract
Apparatus configured detect a physical quantity, for example a density, of a flowing fluid, the apparatus including: a sensor body (2) configured to extend into the flowing fluid, the sensor body comprising a fiber Bragg grating (FBG) of a fiber Bragg grating sensor (3, 7, FBG), for generating a detector signal relating to vibration of at least part (2B) of the sensor body (2); and a processing unit, configured to process the detector signal, and to determine the physical quantity based on detected vibration at a mechanical eigenfrequency of the flexible part (2B) of the sensor body (2).
Claims27
Apparatus configured to detect a physical quantity of a flowing fluid, the apparatus including:
- a sensor body configured to extend into the flowing fluid, the sensor body comprising a fiber Bragg grating of a fiber Bragg grating sensor, for generating a detector signal relating to vibration of at least a flexible part of the sensor body;
- and
- a detector signal processing unit;
- wherein said sensor body part has a mechanical eigenfrequency that is defined by:
- f=f0.(1+K.rho)−1/2
- wherein f is the eigenfrequency (Hz) of the flexible part in fluid, f0 is an initial eigenfrequency (Hz) of the flexible part in vacuum, rho is the density of the fluid (kg/m3) and K is a constant (m3/kg) associated with the dimensions and mass of the flexible part,
- wherein the processing unit is configured to detect the mechanical eigenfrequency f of the flexible part of the sensor body using the detector signal, and to determine the physical quantity based on the detected mechanical eigenfrequency f.
Apparatus configured to detect a physical quantity of a flowing fluid, the apparatus including:
- a sensor body configured to extend into the flowing fluid, the sensor body comprising a fiber Bragg grating of a fiber Bragg grating sensor, for generating a detector signal relating to vibration of at least a flexible part of the sensor body;
- and
- a processing unit, the processing unit having or being associated with a memory, configured for storing an initial eigenfrequency f0 of the sensor body part, the processing unit being configured to utilize the detector signal for detecting an actual eigenfrequency of the flexible part of the sensor body, and for determining a deviation of the detected actual frequency of the natural vibration of the flexible part of the sensor body from the stored initial eigenfrequency of part.
A method of detecting a physical quantity, for example a density, of a flowing fluid, wherein the fluid induces vibration of a flexible part of a sensor body at a first frequency, wherein an eigenfrequency of the vibrating part is being detected, the eigenfrequency being separate from the first frequency, wherein the detected eigenfrequency is processed to determine the physical quantity.
Dependencies are inferred from the claim text.