The Annubar primary element is an averaging Pitot tube manufactured by Rosemount Inc.Rosemount Annubar Flowmeter Series used to measure the flow of fluid in a pipe.
A Pitot tube measures the difference between the static pressure and the flowing pressure of the media in the pipe. The volumetric flow is calculated from that difference using Bernoulli's principle, taking into account the pipe's inside diameter.Perry, Robert H., Don W. Green. "Perry's Chemical Engineer's Handbook, Seventh Edition". pages 10-8 to 10-9. McGraw Hill. 1997 An Annubar, as an averaging Pitot tube, takes multiple samples across a section of a pipe or duct, averaging the differential pressures encountered accounting for variations in flow across the section.
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