Design
The PITOBAR Averaging Pitot Tube is constructed with a diamond-shaped beam and multiple ports that are positioned centrally in concentric rings of equal area, facing the upstream side. This is designed to provide the best averaging measurement of the dynamic pressure, leading to a more accurate flow reading. The pitot tube creates a differential pressure signal proportional to the flow rate: Differential pressure = (Pstatic + Pdynamic) - Pstatic.
Installation
For optimum installation, the pitot tube should be placed in a straight cylindrical tube of uniform cross-sectional area and without obstructions. The internal pipe diameter must not deviate by more than 0.3 % to ensure accurate differential pressure calculations. To ensure accurate measurements, it is recommended to use full flow valves upstream of the primary element. The roughness of the inner pipe wall should fulfil specific limits depending on the material used. In case of vapour flow, horizontal mounting with a slope of 5 degrees is recommended to facilitate condensate flow. Purge connections are available for liquids with impurities, and regular maintenance is recommended to maintain accuracy. For proper instrument connection, the differential pressure transducer should be placed below the pitot tube in liquid and vapour flow, and above it in gas flow, with impulse lines inclined to allow air discharge.
