Carbolite Gero SNF Dilatometric Furnace for Coal Expansion Index Testing

Overview

The Carbolite Gero SNF Dilatometric Furnace is a purpose-engineered benchtop muffle furnace designed exclusively for the standardized determination of the Crucible Swelling Number (CSN) and Free Swelling Index (FSI) of hard coal. It operates on the principle of controlled thermal expansion under defined heating schedules, where coal samples are heated in standardized metal crucibles within a precisely regulated temperature environment. The furnace replicates the critical thermal profile specified in BS ISO 501:2012 and ASTM D720/D720M–15—both of which define the time-temperature ramp, dwell periods, and manual intervention points (e.g., door opening at specific temperatures for crucible removal and visual assessment). Its compact footprint, integrated safety architecture—including 30 mA residual current device (RCD) protection—and thermally stable chamber geometry ensure repeatability and operator safety during procedures requiring periodic access to the hot zone.

Key Features

• Benchtop box furnace architecture optimized for ASTM/ISO coal expansion testing protocols
• PID-controlled 132-series digital temperature controller with high-resolution setpoint adjustment and stable thermal regulation ±1 °C over the 300–900 °C range
• Robust ceramic fiber insulation and double-walled steel construction for uniform radial and axial temperature distribution within the working zone
• Integrated 30 mA RCD circuit protection—mandatory for safe operation during mandated door-opening steps at elevated temperatures
• Standardized crucible support fixture compatible with 26 mm height × 41 mm OD metal crucibles (internal bottom diameter 11 mm), supplied as optional accessory
• Overtemperature cut-off protection (optional) for unattended operation or high-value sample safeguarding
• Modular control interface options: RS232, RS485, or Ethernet-enabled data logging and remote parameter monitoring
• Compliance-ready design supporting GLP documentation workflows through optional multi-segment programmable controllers with audit-trail-capable data recorders

Sample Compatibility & Compliance

The SNF furnace is validated exclusively for use with standardized cylindrical metal crucibles meeting the dimensional and material specifications outlined in BS ISO 501:2012 and ASTM D720M–15. It accommodates single-sample testing per cycle, with strict adherence to prescribed heating rates (e.g., 3 °C/min up to 250 °C, then 30 °C/min to 600 °C), hold times, and manual handling intervals. No modifications or adaptations for non-coal materials or alternative crucible geometries are supported or certified. The system meets CE marking requirements under the EU Machinery Directive 2006/42/EC and Low Voltage Directive 2014/35/EU. Its electrical safety architecture—including protective earth bonding, RCD integration, and thermal cutoff redundancy—aligns with IEC 61000-6-2 (immunity) and IEC 61000-6-4 (emission) standards. For laboratories operating under FDA 21 CFR Part 11 or ISO/IEC 17025 frameworks, optional controllers with electronic signature, user access levels, and tamper-evident audit logs are available.

Software & Data Management

While the base SNF configuration includes a stand-alone 132-series PID controller with local display and manual setpoint entry, advanced configurations integrate programmable logic controllers (PLCs) or industrial-grade data loggers. These support up to 16-segment ramp-soak profiles, real-time temperature graphing, and timestamped CSV export via USB or network interface. Optional software packages provide automated report generation compliant with ASTM D720 Annex A templates, including pass/fail flagging against maximum allowable deviation thresholds (±2 °C). All digital controllers maintain full audit trails—including operator ID, parameter changes, start/stop timestamps, and calibration event logs—enabling traceability for internal QA reviews or external accreditation audits (e.g., UKAS, A2LA).

Applications

• Determination of Crucible Swelling Number (CSN) for coking coal classification per BS ISO 501:2012
• Free Swelling Index (FSI) measurement for coal rank assessment and blend optimization in metallurgical coke production
• Quality control screening of incoming coal batches in power generation and steelmaking facilities
• Research-scale thermal behavior characterization of coal macerals and blends under standardized pyrolysis conditions
• Method validation and instrument qualification (IQ/OQ) for coal testing laboratories seeking ISO/IEC 17025 accreditation

FAQ

Is the SNF furnace suitable for applications beyond coal expansion testing?
No. The SNF is a dedicated, standards-compliant instrument engineered solely for CSN/FSI determination per BS ISO 501 and ASTM D720. It is not validated for general-purpose annealing, ashing, or sintering.
Can the furnace be operated without the RCD protection?
No. The 30 mA RCD is integral to the safety certification and mandatory for compliance with test method requirements involving manual door operation above 300 °C.
What maintenance components are field-replaceable?
All primary wear items—including Type K thermocouples, ceramic thermocouple protection tubes, silicon carbide heating elements, solid-state relays (SSRs), and door gasket assemblies—are available as individual spares or pre-configured service kits.
Does Carbolite Gero supply certified calibration certificates?
Yes. NIST-traceable temperature calibration certificates (per ISO/IEC 17025) are available upon request, covering the full operational range from 100 °C to 900 °C with uncertainty budgets reported per EURAMET cg-18.
Is remote firmware update capability supported?
Firmware updates require local physical connection via USB or serial interface; over-the-air (OTA) updates are not implemented due to regulatory constraints on safety-critical embedded systems.