Flow measurements

Method of measuring the water content in a fluid flow (1) in a pipeline (2),

• characterised in
• forming (71,81,92) with at least one dielectric resonator sensor (3) operated at chosen frequencies an electric field extending out of said resonator sensor (3), said extending field extending mainly into an inner volume section adjacent an inside wall of said pipeline, and
• obtaining (72,82,95) a water content of at least a part of said fluid flow (1) in said inner volume section adjacent an inside wall of said pipeline (2) as a function of a resonant property of each of said at least one resonator sensors (3).

A measuring instrument for flow velocity in a pipeline (2) for transporting fluid hydrocarbon,

• characterized by
• at least one dielectric resonator sensor (3) adapted for forming a time varying electrical field extending from said resonator sensor (3), the extending field extending mainly into an inner volume section adjacent an inside wall of said pipeline, the electric field variation comprising a frequency component corresponding to the TM11 mode of the resonator thus providing two field maxima, and the resonator sensor being oriented relative to the flow direction so that the field maxima are positioned along the flow direction, and
• a measuring unit (9) comprises means for measuring the frequency variations at the two field maxima and to calculate the flow velocity from an autocorrelation of a time series of said measurements.

Method for measuring flow velocity in a pipeline (2) for transporting fluid hydrocarbon,

• characterized by
• forming a time varying electric field extending from a resonator sensor (3), the extending field extending mainly into an inner volume section adjacent an inside wall of said pipeline, the electric field variation comprising a frequency component corresponding to the TM11 mode of the resonator thus providing two field maxima, and the resonator sensor being oriented relative to the flow direction so that the field maxima are positioned along the flow direction, and
• measuring the frequency variations in the field maxima and to calculate the flow velocity from the correlation between said variations and the distance between said maxima.

Use of at least two resonance sensors for measuring flow velocity wherein each of the resonance sensors are adapted for forming a time varying electric field extending from said resonator sensor (3), the extending field extending mainly into an inner volume section adjacent an inside wall of said pipeline, and being coupled to a measuring unit (9) adapted for measuring a resonance frequency of said resonator sensor (3), and wherein the flow velocity is calculated by autocorrelating the measurements from each sensor based on the known distance between the sensors.