Using an aerofoil profile sensor to generate a differential pressure, the Wellbar flow sensor is suitable for a wide range of gases and liquids. The flow sensor is positioned across the flow and has multiple drilling points so that an average differential pressure is generated on the sensor ports. As with other DP flow sensors the flow is proportional to the square root of the DP and flow calculations provided with the sensor, makes it easy to set up a transmitter.
Because of the simple mechanical design, the flow sensors are rugged and can be rated to temperatures to 550C and pressures to 400 bar. This type of flow sensor does not become inordinately expensive as the pipe or duct size increases, and they can be manufactured in lengths up to 15metres.
Flow accuracies of +/-1% and repeatability of 0.1% can be achieved in ideal conditions. This means that velocities will be in the recommended range and the flow will be laminar – upstream and downstream pipe sections straight and constant. Six models assure a wide range of applications can be accommodated. Corrected flow can be obtained using integrated sensors for static pressure and temperature and the flow calculation made by an appropriate device. Standard material of construction is stainless steel.
Flow sensors are generally supplied complete with DP transmitters with displays and push button calibration, for field calibration. Calculations are made for air, water, steam and a variety of common gases and gas mixtures. To propose a system, the supplier needs to know the pipe size, shape and orientation, flow material, pressure, temperature and measurement ranges required.
The Wellbar flow sensor is available from ECEFast .