1) flowmeter
2) flow meter
3) rate-of-flow indicator
4) flow indicator
an instrument which measures the flow of fluid (liquids or gases)
GRM: n. (1,2,3,4)
Note: sometimes the flowmeter is lowered through the flow stream in a borehole; sometimes it is set in one spot with a packer (1); it employs a ball, vane or other means inside a transparent cover, and motion of the ball or vane indicates that fluid is flowing through the pipeline (2)

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