PCME - Model BREAK ALARM 10a - Bag Filters Failure Detectors
The BREAK ALARM 10a is reliable, cost-effective instrument for the continuous monitoring of broken bags in fabric filter baghouses. The instrument combines the benefits of ElectroDynamic™ Probe Electrification technology and a remote control unit with dual local alarms and dual alarm relays, to deliver pragmatic and dependable broken bag monitoring. The BREAK ALARM 10a electronics exclude short term signal increases associated with pulse cleaning of the bagfilter by appropriate setting of the alarm delay period. As a 'Dust Gross Filter Failure Detector', the instrument detects significant increases in particulate loading which indicates a failure in the arrestment plant.
Using PCME's patented ElectroDynamic™ Probe Electrification technology, the instrument extracts a specific frequency band from the induced AC current signature and filters out the DC current caused by particle collisions. The technology outperforms conventional DC triboelectric systems and alternative AC systems by extending the velocity range over which the instrument has no cross sensitivity to changing velocity, and is unaffected by contamination of the sensor rod eliminating concerns of signal drift.
- Dual alarms (early warning and filter failure)
- Separate control unit with tri-state LED for status indication
- Digital averaging avoids false alarms from baghouse cleaning pulses
- BREAK ALARM 30a with scalable 4-20mA output and digital display reading percentage dust level
- Stack temperatures to 250oC
- Duct diameters to 4m
- Dry (non-condensing) applications
- For use after bagfilters also cartridge filters, cyclones and others
- Base dust level response <1mg/m3 to 500mg/m3
- Ideal minimum gas velocity >6m/s
The instruments use PCME’s unique and patented ElectroDynamicTM Probe Electrification technology. The sensor electronics measures the current signature created by particles interacting with the grounded sensing rod which protrudes into the stack. The electronics extract a specific frequency band of this signal and filters out the DC current caused by particle collisions (unlike DC Triboelectric systems and “induction sensing and protected probe” systems).
Advantages from this technology are that the signal generated is:
- Unaffected by contamination of the sensor rod (which causes signal drift issues for other systems),
- Not affected by velocity variations within typical bagfilter velocity ranges (unlike other systems),
- Stable, reliable and does not drift due to electrostatic charging which may occur with protected probe systems in dry flue gas applications.
ElectroDynamicTM Probe Electrification systems have the following added benefits:
- An optimised frequency spectrum to extend the velocity range over which the system has no cross sensitivity to changing velocity (see TUV approvals).
- Unique digital signal processing algorithms in the sensor give the wide dynamic range required for measurement accuracy during arrestment plant cleaning and high reproducibility of signal tracking.
- Uses the same technology as in PCME’s Continuous Emission Monitors (CEMs) approved by MCERTS and TUV.
Dual Alarming for Early Warning
Dual alarming allows operators to configure a Limit Alarm level from 2 to 10,000 units for flexible sensitivity to suit a wide range of process conditions, with the Early Warning Alarm level set to 50% of the Limit Alarm. Operators can set these alarms to instantaneous or average levels above the normal level of emissions to indicate early warning of filter failure or gross failure detection. Alarm delay and data averaging are user selectable.
Digital Averaging Avoids False Alarms
Dust levels are averaged using a ‘walking window’ filter, which when combined with alarm delay ensures minimised false alarms due to short term spikes in dust levels, such as during bagfilter pulse cleaning cycles.
The BREAK ALARM 30a additionally features 4-20mA output scaled to 0-200% of the Limit Alarm level, which is of benefit to plant operators when integrating the instrument with external equipment for trending and external indication of the dust level relative to the instrument’s Limit Alarm. The control unit also features a digital display for convenient remote numerical indication of the dust level relative to the Limit Alarm level (0-200%).