Hardgrove Grindability Tester Model 010G-097

Overview

The Hardgrove Grindability Tester Model 010G-097 is a precision-engineered, benchtop instrument designed to determine the relative ease with which coal and petroleum coke can be pulverized—a critical parameter for power plant boiler design, coal blending optimization, and mill performance prediction. Based on the standardized Hardgrove grindability index (HGI) method, this tester operates on the principle of controlled mechanical attrition under defined load and rotational energy input. It replicates industrial grinding conditions at laboratory scale using a calibrated system of eight 1-inch steel grinding balls rotating within a fixed ring, driven by an upper rotating ring subjected to a precisely applied 284 N (63.5 lbf) vertical force via a standard weight assembly. The motor-driven upper ring rotates at 20 rpm for exactly 60 revolutions—equivalent to 3 minutes of grinding time—after which the drive automatically disengages. This strict adherence to mechanical work input ensures high inter-laboratory reproducibility, as mandated by ASTM D409 and ISO 5074:2016.

Key Features

• Compliance-certified design meeting ASTM D409 and ISO 5074 requirements for HGI determination
• Integrated gear-reduction motor delivering stable 20 rpm rotation with ±0.5 rpm tolerance
• Self-contained, fully enclosed grinding chamber preventing sample loss and operator exposure
• Quick-release lower grinding unit secured by two thumb screws for rapid disassembly and residue-free cleaning
• Automatic rotation counter and cut-off switch ensuring exact 60-revolution termination
• Dual-voltage configuration (220 V / 1 Ph / 50 Hz) optimized for international laboratories operating under IEC-compliant power infrastructure
• Pre-calibrated weight assembly applying consistent 284 N axial load during test execution

Sample Compatibility & Compliance

The Model 010G-097 accepts prepared coal or coke samples sized to 16–30 mesh (0.6–0.5 mm), dried to equilibrium moisture content per ASTM D3173. It accommodates both bituminous coals and low-volatility petroleum cokes, provided feed material conforms to the maximum particle size and moisture specifications outlined in ASTM D409 Section 6. The instrument’s mechanical architecture eliminates variability from operator technique, enabling direct traceability to reference standards. When used with certified reference materials (e.g., HGI 40/60/80/100 coal standards, Catalog No. 010G-098), the system supports GLP-compliant calibration verification and routine performance qualification. All components are constructed from corrosion-resistant stainless steel and hardened tool steel to maintain dimensional stability over repeated thermal and mechanical cycles.

Software & Data Management

This analog-digital hybrid instrument does not incorporate embedded software or data logging firmware; instead, it delivers inherently traceable mechanical endpoints—60 revolutions and fixed load—that align with paper-based recordkeeping systems required under legacy QA/QC protocols. Test results are calculated manually following ASTM D409 Equation 1: HGI = 13 + 6.93(50 − W), where W is the mass (g) of undersize fraction (<0.074 mm) retained on a 200-mesh sieve after sieving the ground sample. Laboratories implementing electronic lab notebooks (ELN) or LIMS may integrate raw mass inputs and final HGI values via structured CSV upload. While the device itself lacks FDA 21 CFR Part 11 compliance features, its deterministic operation supports audit-ready documentation when paired with controlled SOPs, signed test records, and periodic calibration logs per ISO/IEC 17025 Clause 6.5.

Applications

• Predicting coal pulverizer power consumption and throughput in thermal power generation facilities
• Evaluating coal blend compatibility to avoid mill choking or excessive wear in multi-source fuel systems
• Quality control of incoming coal shipments against contractual HGI specifications
• Research into coal rank effects on comminution behavior and particle size distribution evolution
• Method validation studies supporting ISO/IEC 17025 accreditation for coal testing laboratories
• Training platforms for ASTM D409 proficiency testing and interlaboratory comparison programs

FAQ

What standards does the Model 010G-097 comply with?

ASTM D409 (Standard Test Method for Determining the Grindability of Coal Using the Hardgrove Machine) and ISO 5074:2016 (Hard coal — Determination of Hardgrove grindability index).
Is the instrument supplied with calibration reference materials?

No—the base unit (010G-097) includes only the tester, weights, and standard operating instructions. Certified reference coals (HGI 40/60/80/100) are available separately under Catalog No. 010G-098.
Can the tester be used for non-coal materials?

While primarily validated for coal and petroleum coke, limited application exists for other brittle, non-fibrous carbonaceous solids—but HGI values derived from such materials lack standardized interpretation and should be reported with method deviation statements.
What maintenance is required for long-term accuracy?

Annual verification of grinding ball diameter (±0.02 mm tolerance), ring surface flatness (≤0.05 mm deviation), and motor speed stability using a calibrated tachometer is recommended per ASTM D409 Annex A1.
How is sample recovery ensured during cleaning?

The sealed grinding chamber retains all particulate matter; removal of the lower grinding unit via two thumb screws allows complete access for dry brushing—no solvents or compressed air required, preserving sample integrity and minimizing cross-contamination risk.