Gas Flow Meters with 4-20mA Output

Yes. All OFS series optical flow sensors are designed and certified for EPA 40 CFR Part 75 compliance, making them suitable for continuous emissions monitoring at power plants, industrial stacks, and flare systems. They support mass emissions reporting in pounds of pollutants per day, meeting federal environmental regulatory requirements.

No. OSI gas flow sensors are factory pre-calibrated and feature drift-free measurement technology with a built-in automatic calibration check. Field calibration is never required. This eliminates ongoing calibration costs and compliance downtime, making them significantly lower maintenance than traditional pitot-tube or ultrasonic flow measurement alternatives.

The OFS-2000 standard model measures 0–100 m/sec, suitable for most industrial stack and duct applications. The OFS-2000F, designed specifically for flare stacks, extends the range to 0.03–170 m/sec for very low and very high flow conditions. The OFS-2000W also covers 0–100 m/sec with Automatic Gain Control for high-opacity environments.

Yes. The OFS-2000W model is specifically engineered for high-opacity environments such as wet scrubbers and bag houses, featuring Automatic Gain Control (AGC) that compensates for variations caused by particulate matter or moisture. All OFS sensors are unaffected by temperature, pressure, gas density, moisture, or opacity changes during normal operation.

OFS sensors mount using a standard ANSI pattern 4-inch pipe flange. Installation requires a minimum of 2 upstream diameters and 1 downstream diameter of straight duct run for accurate measurement. The non-intrusive cross-stack design means there is no pressure drop introduced into the process, and no hot-tap penetration of the gas stream is required.

The OFS-2000 supports RS-232, MODBUS RTU, and optional RS-485, Ethernet, and cellular modem communications. It operates on nominal 12 VDC (max 400 mA) and is solar compatible for remote installations. The system provides data updates once per minute with instantaneous intensity readings every 10 seconds, and operates across -50°C to 60°C ambient temperatures.