PCME - Passionate about Particulate

The BREAK ALARM 30a 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 a scaled 4-20mA output, dual local alarms and dual alarm relays, and a digital numerical display to deliver pragmatic and dependable broken bag monitoring. The BREAK ALARM 30a 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.

• 4-20mA output scaled to 0-200% of primary alarm level (which is user defined), for external indication of dust level relative to alarm set point
• High quality leak response with sufficient dynamic range and time response to track emissions from single and multi-compartment pulse cleaned bagfilters
• Dual alarming for filter failure and early warning, user set to instantaneous or average levels above normal level, alarm delay and data averaging
• Separate control unit for remote installation with digital numerical display for % dust level reading, and tri-state LED (alarm 1, alarm 2 & status)
• ATEX category 3G/3D for gas zone 2 and dust zone 22

Control Unit with Digital Display

Similar to the BREAK ALARM 10a but with the addition of a digital display, the BREAK ALARM 30a control unit provides convenient remote numerical indication of the dust level % relative to the primary alarm level (0-200%).

4-20mA output

The BREAK ALARM 30a provides a 4-20mA output scaled to 0-200% of the primary alarm level (Limit Alarm), which is of benefit to plant operators wishing to integrate the instrument with external equipment for trending and external indication of the dust level relative to the instrument’s Limit Alarm.

Dual Alarming for Early Warning

Dual alarming allows operators to set Early Warning and Limit Alarms, configurable via a simple to use control unit. The Limit Alarm is configurable from 2 to 10,000 units, for flexibility of sensitivity to suit a wide range of process conditions, while the Early Warning Alarm is set to 50% of Limit Alarm level. The user has the ability to set the alarms to instantaneous or average levels above the background or normal level of emission 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.
 

Process Conditions

The BREAK ALARM 30a is suitable for:

• Stacks after bag filters, cartridge filters, cyclones
• Constant or variable velocities within range 8-20m/s (typical bagfilter velocity ranges), constant velocity required outside this range
• Non-condensing / dry flue gases*
• Explosive atmosphere zones 2 and 22
• Not suitable for electrostatic precipitators or applications with water droplets*

* For wet / condensing flue gas applications see PCME STACK 181 WS

Typical Applications

The BREAK ALARM 30a is used in a broad range of industries, where indicative filter failure monitoring is required after baghouses and cartridge filters, including the following types of processes:

• Timber sawing plant
• Chemical industry eg coating plant
• Metals refining
• Tobacco plant
• Food industry e.g. packing/filling plant
• Minerals industry e.g. brick, cement kiln