Drift-Free Gas Flow Measurement Solutions

A Differential Pressure Transmitter (DPT) flow meter works by measuring the pressure drop across a flow restriction element, such as an orifice plate or pitot tube. The pressure difference correlates with flow velocity via Bernoulli's equation. Unlike DPT meters, OSI's optical flow sensors are entirely non-intrusive, creating no pressure drop and eliminating the moving parts and drift issues common to differential pressure-based systems.

Several instruments measure gas flow, including pitot tubes, differential pressure meters, ultrasonic flow meters, thermal mass flow meters, and optical flow sensors. OSI manufactures optical scintillation-based flow sensors such as the OFS-2000 and OFS-2000F series, which are non-intrusive, drift-free instruments specifically engineered for industrial stack, flare, wet scrubber, and bag house environments requiring EPA 40 CFR Part 75 compliance.

No. OSI optical flow sensors are factory pre-calibrated using a NIST-certified algorithm and require no field calibration ever. The sensors feature built-in automatic calibration checks and continuous self-test diagnostics, ensuring measurement accuracy and reliability throughout the sensor's operating life without any scheduled recalibration events.

Yes. OSI's OFS-2000, OFS-2000W, OFS-2000F, and OFS Optical Flow Sensor series are all capable of supporting EPA 40 CFR Part 75 compliance for stack gas flow monitoring. The sensors use a NIST-certified measurement algorithm and are suitable for emissions monitoring and mass flow reporting requirements at power plants, refineries, and other regulated industrial facilities.

OSI optical flow sensors are engineered for challenging industrial environments, including high-temperature stacks, flare systems with extreme velocity ranges (0.03–170 m/sec), wet scrubbers with high moisture and particulate content, bag houses with variable opacity, incinerators, thermal oxidizers, carbon capture systems, and aluminum smelter pot rooms with corrosive HF gas exposure.

Optical scintillation sensors measure gas flow non-intrusively by projecting an infrared beam across the full stack or duct diameter. Unlike pitot tubes or probe-based meters, there are no moving parts, no pressure drop is introduced, and measurements are spatially averaged rather than point-based. This results in higher accuracy, zero maintenance downtime, and immunity to temperature, pressure, gas density, and opacity variations.