Opacity and dust monitoring systems depend on a constant flow of purge air to protect exposed optical components against flue gas contamination in industrial stack monitoring applications.
But an unexpected failure of the purge system can prove to be a costly exercise for owners not just in repair costs, but also when downtime restrictions apply to monitoring equipment under EPA site license conditions.
In critical applications, Fail Safe Shutters are installed to automatically isolate the opacity monitor from flue gas contamination in the event of a system power failure, or the loss of purge airflow.
Usually the Fail Safe Shutter is powered to the open position by a rotary solenoid and closed under spring tension during the period of system risk.
Unfortunately, when the Fail Safe Shutter is called upon to protect the opacity monitoring system, it is common to find that the mechanical components have seized up due to contamination, corrosion, or lack of use.
Because of the nature of the task, a problem is detected only at the time of need.
The new Opal FSS Fail Safe Shutter system is designed to overcome such uncertainty by being fully integrated into the control and test procedures of the Opal opacity monitoring system.
As the Opal 200 system conducts it daily self test procedure for zero and span calibration, an additional test cycle is included where each failsafe shutter is automatically closed and opened to ensure reliability
The Opal FSS has internal sensors to provide feedback of successful open and shut positions to the control unit.
Failure to operate correctly will raise an alarm signal and the control unit display will identify which shutter unit (transceiver or retroreflector) has failed to test correctly.
In addition, each Opal FSS has an inbuilt manual test switch to assist technicians during routine and breakdown service.
Each Opal FSS is supplied complete with an in-line air flow switch for detection of decrease or loss of purge air flow.
The FSS Fail Safe Shutter system is available from Opal Environmental.