The biggest difference between an annubar and a pitot tube is that an annubar takes multiple samples across a section of a pipe or duct. In this way, the annubar averages the differential pressures encountered accounting for variations in flow across the section. A pitot tube will give a similar reading if the tip is located at a point in the pipe cross section where the flowing velocity is close to the average velocity.
I caught up with Emerson’s Kathryn Hausman who shared several videos with me showing the most recent updates to Annubar technology. In the first 2:09 Youtube video, Technology Demo – Rosemount 405A Compact Annubar Flowmeter, Kathryn highlights how the Rosemount Compact Annubar Flowmeter design reduces installation and energy costs.
In the video, she shares some of the advancements to this technology, which includes improved energy efficiency through reduced permanent pressure loss, simplified installation between existing raised-face flanges, self-centering ring design to improve installation and measurement accuracy, and real-time mass and energy flow measurements available with integral temperature.
This 2:40 video shows the Rosemount 405A Compact Annubar Flowmeter Installation process:
This 2:58 video shows the Rosemount 485 Annubar Pak-Lok Flowmeter Installation process: