Air Flow Meters with RS485 Output

Optical scintillation technology measures air flow by detecting variations in an infrared beam transmitted across the measurement path. Turbulent eddies in the flowing gas cause intensity fluctuations that are analyzed using a NIST-certified digital signal processing algorithm to calculate velocity. This non-intrusive approach requires no contact with the gas stream and is unaffected by temperature, pressure, moisture, or opacity changes.

No. OSI's optical flow meters are factory pre-calibrated and feature drift-free measurement that never requires field calibration. Built-in automatic calibration checks and continuous self-test diagnostics ensure ongoing measurement integrity throughout the product's operational life, eliminating costly recalibration downtime and service visits.

Yes. The OFS-2000, OFS-2000F, OFS-2000W, and OFS-2000 Series optical flow sensors are all EPA 40 CFR Part 75 compliant for continuous emissions monitoring at power plants and industrial facilities. The measurement algorithm is certified by NIST and has been validated with over 20 million hours of observation data in stack flow applications.

OSI offers two primary measurement ranges. The standard OFS-2000 and OFS-2000W cover 0–100 m/sec, suitable for most industrial stack and duct applications. The OFS-2000F, designed specifically for flare stacks, covers an extended range of 0.03–170 m/sec to accommodate the extremely low and high velocity conditions typical of flare operations.

Yes. The OFS-2000W model is specifically equipped with Automatic Gain Control (AGC) to compensate for opacity variations caused by particulate matter, moisture, or liquid droplets. All OFS sensors are unaffected by changes in gas density, temperature, and moisture, making them reliable in wet scrubbers, bag houses, and other challenging industrial environments.

OSI optical flow meters require a minimum of 2 upstream and 1 downstream pipe diameters of straight duct for accurate measurement. They mount using a standard ANSI pattern 4-inch pipe flange. Hot tap installation procedures are available for installations where process shutdown is not feasible, and field engineering support is provided to ensure correct alignment and commissioning.