MingShen Science PZD-8 Free-Crucible Thermal Dilatometer for Crucible Swelling Number (CSN) Determination

Overview

The MingShen Science PZD-8 Free-Crucible Thermal Dilatometer is a dedicated benchtop instrument engineered for the standardized determination of the Crucible Swelling Number (CSN), a critical empirical index used to assess the caking and coking behavior of bituminous coals. Based on the principle of free thermal expansion under controlled heating in an open crucible, the PZD-8 implements the gravimetric–dimensional methodology defined in GB/T 5448–2014 (“Determination of Crucible Swelling Number of Bituminous Coal — Electric Heating Method”) and aligned with ASTM D5867–22 (“Standard Test Method for Determining the Crucible Swelling Number of Coal”). Unlike conventional dilatometers that measure linear dimensional change of solid rods or discs, the PZD-8 monitors the vertical expansion and subsequent contraction of a coal charge undergoing pyrolysis and semi-coke formation in air, producing a characteristic “swelling profile” that is visually matched against a certified reference set of nine standard coke buttons (CSN 1–9). The system integrates a programmable microprocessor-based temperature controller, a high-stability resistance-heated furnace, and real-time timing logic synchronized to ISO/IEC 17025-compliant timekeeping standards.

Key Features

• Compliance-ready architecture: Fully implements the procedural sequence mandated by GB/T 5448–2014—including preheating to 930 °C, 10-minute isothermal hold, 2.5-minute ramp to 820 °C ±5 °C, and precise 3-minute total reaction duration.
• Dual-K thermocouple redundancy: Two independently calibrated Type K thermocouples provide cross-verified furnace temperature feedback, ensuring traceable thermal uniformity across the crucible zone.
• Optimized thermal design: Silicon-alumina fiber insulation minimizes heat loss and enables rapid, energy-efficient heating (≤1000 W input) while maintaining axial temperature homogeneity within ±5 °C over the 30 mm crucible height.
• Integrated visual assessment station: Includes a calibrated observation tube with standardized illumination and side-view alignment optics, enabling direct side-profile comparison of the resulting coke button against NIST-traceable CSN reference charts.
• Robust control logic: Microcontroller firmware prevents thermal overshoot via adaptive PID tuning; audible and visual alerts at key timepoints (e.g., 2 min 30 s, 3 min) eliminate operator timing errors.
• GLP-supportive operation: All timing events, temperature setpoints, and alarm triggers are logged internally with timestamp resolution of 1 second—facilitating audit trails for quality assurance systems operating under ISO/IEC 17025 or internal QA protocols.

Sample Compatibility & Compliance

The PZD-8 accepts standard 15 mm ID × 25 mm H porcelain crucibles (supplied as part of standard configuration) loaded with precisely 1.00 ±0.01 g of air-dried, <0.2 mm pulverized bituminous coal sample. No sample encapsulation or inert gas purging is required; testing occurs exclusively in ambient air atmosphere per GB/T 5448–2014 and ASTM D5867–22. The instrument meets mechanical and electrical safety requirements per IEC 61010-1:2010 (Measurement, Control and Laboratory Equipment). Its temperature control performance satisfies Class 0.5 accuracy per IEC 60584-2, and timing stability complies with ISO 9001 clause 7.6 requirements for monitoring and measuring equipment calibration.

Software & Data Management

The PZD-8 operates via embedded firmware with no external PC dependency. All operational parameters—including preset temperature targets, hold durations, and alarm thresholds—are configurable via front-panel membrane keys (“Set”, “▲”, “◀”, “Confirm”). Internal non-volatile memory retains up to 100 test records, each storing start time, peak temperature, actual ramp time, final CSN assignment (operator-entered), and pass/fail status relative to method-defined tolerances. Data export is performed manually via RS-232 serial interface (optional USB-to-serial adapter supported) using ASCII-formatted text files compatible with LIMS platforms compliant with FDA 21 CFR Part 11 Annex 11 requirements when paired with validated third-party data capture software.

Applications

• Routine quality control of run-of-mine and washed bituminous coals in coal preparation plants and power generation facilities.
• Coal blending optimization in coke oven battery operations, where CSN values predict coke strength after reaction (CSR) and coke reactivity index (CRI).
• Research into coal rank–reactivity relationships, particularly for low- to medium-volatile bituminous coals exhibiting strong swelling behavior.
• Verification of coal supplier specifications during procurement audits and contractual dispute resolution.
• Training and proficiency testing in coal testing laboratories seeking CNAS or UKAS accreditation under ISO/IEC 17025.

FAQ

What coal types is the PZD-8 designed for?
The PZD-8 is validated exclusively for bituminous coals meeting the volatile matter (daf) range of 20–35% and ash content <15%, as specified in GB/T 5448–2014. It is not suitable for anthracite, lignite, or petroleum coke.
Does the instrument require calibration certification?
Yes. Annual calibration of both thermocouples (against NIST-traceable reference junctions) and the internal timer (using GPS-synchronized stopwatch) is recommended to maintain compliance with ISO/IEC 17025 Clause 6.5. Calibration certificates are provided upon request.
Can the PZD-8 operate under nitrogen or argon?
No. The method requires oxidative conditions to replicate industrial coke oven behavior; substitution of inert atmosphere invalidates CSN interpretation per GB/T 5448–2014.
Is the observation tube included in the base configuration?
Yes. One calibrated side-view observation tube with integrated LED illumination and standardized magnification (5×) is supplied as standard equipment.
How is CSN value assigned?
The operator visually compares the lateral profile of the cooled coke button against the official nine-grade reference chart (CSN 1 through 9); no algorithmic image analysis is performed—the assignment remains a human expert judgment per standard practice.