- February 07, 2025
- FCI - Fluid Components International
Feb. 6, 2025 - Municipal wastewater treatment plant engineers and technicians concerned about process efficiency and the high cost of energy to power large air compressors that support their aeration basins will find that the precision, rugged ST50 Thermal Mass Flow Meter from Fluid Components International (FCI) delivers accurate air flow measurement that will optimize their treatment processes and reduce energy costs significantly.
The FCI ST50 Series Thermal Mass Flow Meter offers several important advantages. Thermal flow meters directly measure the mass flow rate of air without the need for other components, such as the flow calculators required by other flow sensing technologies. Direct mass flow measurement is crucial in aeration basins because the biological processes depend on the mass flow of air/oxygen delivered to the basins, not just simply the volume of air.
Thermal mass flow measurement sensor technology is also unaffected by changes in temperature and pressure, which can impact the density and thus the oxygen content of the air. Maintaining proper oxygen levels in the aeration basins is essential to ensure effective, consistent aeration control regardless of changing environmental conditions within these large basins.
Wide swings in air flow demand are also common in continuously operating wastewater treatment plants as load demands naturally cycle up and down over a 24-hour period. The wide rangeability and high repeatability of FCI thermal mass flow meters means they can accurately measure flow rates over a wider range consistently without sacrificing accuracy during low flow demand cycles.
The ST50 Series Flow Meters, due to their unique design, also exhibit very low pressure drop in the air flow line. Maintaining higher line pressure unaffected by instruments helps maintain equipment efficiency and therefore reduces air compressor energy consumption. The low pressure drop of thermal mass flow meters also minimizes the potential risk of flow disturbances elsewhere in the line that could affect measurement accuracy and other equipment performance.
FCI’s ST50 Series Flow Meters feature a rugged no-moving parts sensor design in a robust insertion style package for a simple, fast single-tap point installation into existing pipes that takes only minutes. They also require virtually no maintenance over a long lifespan that is typically decades in length for both the lowest installed cost and lowest lifecycle cost, which saves operators money upfront and beyond. These meters pay for themselves (ROI) relatively quickly.
FCI’s ST50 Series Thermal Mass Flow Meter is accurate over a wide flow rate from 0.75 to 400 SFPS (0,23 to 122 MPS). Flow accuracy is ±1% of reading, ±0.5% full scale, with repeatability of ±0.5% of reading. Turndown capabilities are as high as 100:1.
The ST50 Flow Meter’s electronics are housed in a rugged, IP66/IP67 rated enclosure with dual conduit ports in either NPT or M20 threading. The instrument comes standard with dual 4-20 mA outputs - one for flow rate, and one for temperature. A 500 Hz pulse output (for external totalizer) can be added as an option. The transmitter/electronics can be integrally mounted with the flow element (probe) or be remote mounted to best match the installation situation requirements.
One of the biggest expenses in wastewater treatment is the cost of energy to run the compressors and blowers that move air. The industry figures most often cited indicate that 40 to 50 percent of a wastewater plant’s total energy usage can be attributed to the aeration process. Using FCI’s ST50 Series Flow Meter to help provide the proper flow of air with the optimum oxygen level into the aeration basins helps ensure that microorganisms effectively break down organic waste.
Several types of flow meters have been used in wastewater aeration treatment to measure air flow, such as thermal, orifice plates and vortex shedding. Thermal flow meters because of their accuracy, wide rangeability, low pressure drop and wide turndowns are now becoming the preferred choice. The FCI ST50 Series Thermal Flow Meter helps engineers and technicians achieve better air/oxygen flow control with higher efficiency and at lower total operating costs.
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