Preso, Racine, WI, offers the Ellipse flowmeter that measures actual differential pressure with ±0.75% accuracy of reading and ±0.1% of reading repeatability. The flowmeter has a series of ports facing the upstream velocity pressures and flow sensing ports ahead of the trailing edge flow separation to achieve the higher accuracy as well as a 17:1 turndown ratio, with no vacuum effects. Typical pressure loss is 3% in a 12 in. line.
Elliptical Flowmeter from Preso