FCI ST98 flowmeter with Vortab Insertion Panel flow conditioner

The FCI ST98 flowmeter with Vortab VIP conditioner is suitable for wastewater treatment aeration system control.

Wastewater treatment plant engineers in search of an accurate, economical solution for air/gas flow measurement in aeration basins will find that Fluid Components International’s precision ST98 Thermal Mass Flow Meter, when combined with the Vortab Insertion Panel (VIP) Flow Conditioner, provides good performance to minimise compressed airflow energy costs.

In wastewater treatment plants, a variety of processes is employed to eliminate organic pollutants from water. The activated sludge method requires the pumping of compressed air into aeration basins where a diffuser system ensures the air is distributed evenly for optimum treatment. Large amounts of compressed air are required to ensure the aeration process operates effectively, with flowmeters installed in the system piping to help monitor the air that is released into the basins. This is essential because the airflow controls the growth of microorganisms that treat the wastewater.

Precisely controlling the airflow is necessary to reduce compressed air energy costs, which are one of the largest expenses in the treatment process. The ST98, in combination with the VIP flow conditioner, is suitable for this task because of the meter’s accurate performance over a wide flow range, ease of installation and low maintenance requirements. It features a no-moving-parts thermal dispersion mass flow sensing element that provides accuracy and reliability in harsh environments. The ST98 also includes an integral 2-way HART interface, which allows engineers to receive multiple process variables and configure the meter remotely from the safety of the control room.

The flowmeter provides high accuracy to ±1% of reading, 0.5% of full scale. Repeatability is ±0.5% of reading. This insertion-style flowmeter can be installed without shutting down the process by using a simple NPT fitting. The ST98 operates over a wide flow range from 0.21 to 172 nmps, and the turndown ratio is factory preset from 10:1 up to 100:1. It operates at pressures up to 7 bar (g).

The VIP flow conditioner compensates for flow disturbances in wastewater treatment aeration basin compressed air piping systems. Vortab technology is claimed to reduce pressure drop compared to alternative technologies such as tube bundles, screens and perforated plates, which helps minimise plant energy consumption and costs.

Many flowmeter technologies require several diameters of straight pipe run to meet their meter’s accuracy specifications, and the VIP flow conditioner solves this pipe straight-run dilemma. A VIP installed at just three pipe diameters downstream from the flow disturbance, with the flowmeter installed at just three pipe diameters downstream of the VIP, neutralises the flow disturbance and produces a symmetrical and swirl-free repeatable flow profile.