Sensor; Principle Of Operation - Pentair Goyen Mecair FFD Installation And Operation Manual

3.3 SENSOR

The sensor comprises a metal probe rod that protrudes into the stack and connects to the stack via the hexagonal
body connected to the sensor enclosure, which contains the advanced electronics module. The sensor is fitted to the
stack using a ½" BSPP threaded socket and is secured with a lock nut. The instrument requires 24 V DC, nom. Refer to
page 6 for details of ATEX-related conditions and requirements.
The FFD is suitable for use in applications of up to 200°C (390°F).
Adjustable Alarm Levels
Dual alarming enables operators to configure early warning and limit (high) alarm levels providing flexible sensitivity to suit
the process. Dust levels are averaged – or smoothed – using a 'walking window' filter to avoid triggering false alarms due
to temporary spikes in dust levels, e.g. during bag-filter cleaning cycles.

3.4 PRINCIPLE OF OPERATION

The FFD sensor utilizes Probe Electrification measurement technology. The sensor measures the interaction between
the particulate in the air stream and the sensing rod to induce a charge signature. The instrument extracts a specific
frequency band and filters out the DC current caused by direct particle collisions. The technology outperforms conventional
DC tribo-electric systems by extending the range over which the instrument has minimal cross-sensitivity to changing
velocity while remaining unaffected by the build-up of particulate on the sensing rod, thereby minimizing signal drift.
INSTALLATION AND OPERATION MANUAL – OWNER'S RECORD FFD MANUAL – FILTER FAILURE DETECTOR 05