PCME STACK 990
The PCME STACK 990 is an approved particulate Continuous Emission Monitor suited to industrial applications in stacks after bag filters, cartridge filters, cyclones and process driers. The instrument combines regulatory approvals (TUV BlmSchV 17 and 13) for both dust measurement and leak monitoring, with reliable automatic quality assurance features, rugged operation and advanced diagnostics for the management and optimisation of arrestment plant.
Options include Ex Gas Zone 2 and Dust Zones 20, 21 and 22, up to 800°C stack temperature operation and Hastelloy® enhanced corrosion protection; The PCME STACK 990 is used extensively for particulate measurement (mg/m3) and bagfilter leak location across a broad range of challenging applications.

Patented insulated sensor rod option for use in high humidity applications
Patented ElectroDynamic™ Probe Electrification technology 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.
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Patented probe rod insulation monitor providing operator with early warning of possible probe short circuit. Unique to PCME, this technology enables predictive sensor maintenance scheduling, lower down times and additional confidence in signal quality
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Additional system self-checks to validate measurement integrity including automatic Zero and Span checking
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ATEX / IECEx category 3G/1D/2D/3D for gas zone 2 and dust zones 20, 21, 22
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PC-ME Dust Tools PC software option to provide secure and powerful emissions reporting, real-time and historical data analysis
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Entry and Standard control unit with advanced graphic and user interface screens, features including alarming, graphical trending, data logging, 4-20mA output.
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PLUS control unit option for sensor networking (up to 16 sensor channels) via industry standard Modbus, multiple inputs for external devices (e.g. for Temp and O2 normalisation)
The PCME STACK 990 supersedes the DT990, an instrument proven in demanding CEM applications worldwide.
Automatic Functionality and Quality Assurance Checks
The PCME STACK 990 features comprehensive automatic self checks to ensure regulatory compliance and to provide plant operators with pre-emptive warning of potential sensor issues to allow preventative maintenance scheduling, lower process down times and confidence of data integrity:
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Automated Zero and Span drift checks to enable a simplified process for operators to meet regulatory standards
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Patented probe rod contamination check, measures and reports condition of probe-to-stack insulation ring for maintenance scheduling, before short circuit can occur
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Probe rod short circuit check enables operator to know when the sensing rod may be electrically shorted to the stack and avoid associated errors
Advanced Signal Processing and Diagnostics
Accurate emission measurement with rapid dynamic ranging allows plant operators to locate the position of leaking bags in multi-compartment bag filters. When integrated with PCME's Predict PC software this provides ultimate arrestment plant fault finding capability:
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Rapid dynamic ranging of 10,000:1 permits bag cleaning pulses to be accurately monitored while maintaining high accuracy in background emission measurement. Sufficient dynamic ranging is provided to follow "on-line" and "off-line" bag cleaning cycles for predictive filter failure and faulty bag location detection
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Rolling ('walking window') digital average calculations for accurate emission measurement
Durable Sensor Options for Varied Applications
Standard sensors for probe electrification instruments will only perform under certain process conditions. For example, conductive particulate matter, high levels of humidity, explosive and corrosive atmospheres will present different challenges to probe electrification technologies, can cause errors in measurement or potentially damage the instrument. The PCME STACK 990 offers a range of rugged, durable sensor options to address challenging stack conditions:
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Patented insulted sensing rod option, significantly increases the maintenance interval required for probe electrification type instruments used in humid flue gases or where conductive dusts are present, and provides unrivalled performance in process drier applications
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Active/passive design - sensor is available with passive section between active sensing probe and stack connection stub, eliminating concerns over potential short circuits by bridging in the connection stub caused by condensation
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Optional Hastelloy® stack connection to provide enhanced galvanic corrosion protection, preserves the integrity of the electrical ground through stack connection
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ATEX/IECEx certified for gas zone 2, dust zones 20, 21, 22
Process Conditions
The PCME STACK 990 is suitable for:
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Stacks after bag filters, cartridge filters, cyclones
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Constant or variable velocities within range 8-20m/s (typical bagfilter velocity ranges), constant velocity required outside this range
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After process driers
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Non-condensing / dry flue gases*
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Explosive atmosphere zones 2, 20, 21 and 22
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Not suitable for electrostatic precipitators or applications with water droplets*
* For wet / condensing flue gas applications see PCME STACK 181 WS
Typical Applications
The PCME STACK 990 is used to monitor emissions from the following types of processes:
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Quarrying (eg Rotary Dryers, Roller Mills)
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Carbon Black filter plant
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HEPA filters (eg pharmaceutical / biomedical plant)
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Coal Mill / Cement Mill / Cement Kiln arrestment plant
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Humid application eg Dryers, Calcinators
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Wood cutting & chipping plant
Performance
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Approvals |
TUV (BlmSchV 17, 13)
more on approvals |
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Certification Range |
0-15 mg/m3 (TUV) |
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Measurement Capability |
0-500 mg/m3 |
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Long Term Zero Drift |
< 0.1 mg/m3 |
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Air Purge Requirement |
May be required on some applications (consult PCME), 5-10 litres/min of dry, clean, oil free instrument air |
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Inspection Frequency |
6 months (dependant on application) |
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Stack Diameters |
100mm - 6m (flow profile dependant on large stacks) |
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Stack Temperatures |
0-250°C (option to 800°C) |
Sensor
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316 stainless, or fully insulted PTFE coated option for conductive dust or humid flue gas application
Stack temperature ranges 0-250°C, 0-400°C, 0-800°C
Standard, or with Passive section (for short circuit prevention by creating clearance between active section of sensor and potential contamination 'bridging' sites)
RS485 (Modbus) output to control unit
Local 4-20mA and Alarm Relays for DCS integration
24VDC power supplied via control unit
IP65 die-cast aluminium enclosure
ATEX/IECEx category 3G/1D/2D/3D for gas zone 2 and dust zones 20, 21, 22
Air Filter and Regulator assembly for plant instrument air (air purge typically not required for most applications) |
Control Unit

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Single Channel Entry and Standard units, or 1-16 Channel PLUS MultiController unit for extended sensor networking capability
Industrially hardened display screen and enclosure with icon driven, multilingual menus for intuitive user interface
Data logging: Simultaneous recording of pulse data (for arrestment plant cleaning diagnostics), short term data (for process control), long term data (for external emissions reporting), and Alarm log for up to 500 alarming events
Alarming: Local (audible and visual), and via 4 x user selectable relay outputs (PLUS), expandable via 'ROM' module
Ethernet (Modbus TCP) connectivity for industrial network integration
4 x 4-20mA and 1 x RS485 (Modbus RTU) outputs (PLUS), expandable via 'AOM' module
External Inputs: Accepts input data from external devices (e.g. for temp and O2 normalisation, plant off indication, bag cleaning reference, multiple calibrations) via digital and 4-20mA inputs, expandable via 'AIM' module
Pulse log review to diagnose location of leaking bags |