The Optical Flow Sensor (OFS), available from Thomson Environmental Systems , is a continuous flow measurement system for small and large stacks and ducts.
The Optical Flow Sensor meets all 40 CFR 75 requirements, including daily zero and span checks and is available as a rack mount or NEMA-4X unit.
The Optical Flow Sensor consists of a control panel teamed with an optical transmitter and optical receiver. The transmitter and receiver are installed in-line with each other on opposite sides of the smokestack, duct or vent. There is no need for a 45 degree angle mounting.
An LED beam from the receiver is directed straight across the stack, perpendicular to the flow. Long term drift for this system is less than ±1%.
The Optical Flow Sensor resides outside the stack chamber, behind the optical windows. This provides added protection, reduced maintenance and easy access to the OFS components.
The Optical Flow Sensor utilises optical scintillation technology. It measures the movement of turbulence found in the sample stream or exhaust. This method ensures measurements are not effected by gas composition or temperature. The control panel processes the data and transmits it to data collection devices through 4-20mA or digital signals.
The Optical Flow Sensor comes fully equipped with self-testing and diagnostic features to monitor its own performance and alert the user if maintenance is required. Instrument malfunction and limit alarms are also available in the control panel.