Flowmeter for measuring the flow rate of a two phase fluid in a pipe

摘要

A flowmeter for measuring the flow rate of a two phase liquid in a pipe having a first pipe section (11) having a first diameter (D1), a second pipe section (12) of a smaller diameter (D2), an internally tapering transition pipe section (13) forming a smooth transition between the first and second pipe sections (11, 12), and three pressure tapping points comprising upstream (At.sub.u, Bt.sub.u, Ct.sub.u), downstream (At. sub.d, Bt.sub.d, Ct.sub.d) and intermediate tapping points (At.sub.i, Bt. sub.i, Ct.sub.i), in which a first differential pressure monitoring arrangement is provided to measure the pressure differential between the upstream and the downstream tapping points and form which fluid density can be derived, and a second differential pressure monitoring arrangement is provided to monitor the pressure differential between the intermediate tapping point and one of the upstream or downstream tapping points, whereby flow rates can be calculated from the derived density value and the second differential pressure measurement.