GuanCe GEST-122A.3 Portable Graphite Electrode Resistivity Tester
| Brand | GuanCe |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Authorized Distributor |
| Country of Origin | China |
| Model | GEST-122A.3 |
| Output Current | 35 A |
| Resistance Measurement Range | 2 µΩ to 200 mΩ |
| Resolution | 0.1 µΩ |
| Accuracy Class | 0.5 |
| Operating Temperature | −10 °C to +50 °C |
| Operating Humidity | 0–80 % RH (non-condensing) |
| Power Supply | AC 220 V ±10 %, 50 Hz ±1 Hz |
| Weight | 4 kg |
Overview
The GuanCe GEST-122A.3 Portable Graphite Electrode Resistivity Tester is a compact, field-deployable DC four-terminal resistance measurement system engineered for precise determination of bulk electrical resistivity in graphite electrodes and related carbonaceous materials. It operates on the principle of constant-current DC injection (35 A) combined with Kelvin (four-wire) voltage sensing to eliminate lead and contact resistance errors—ensuring traceable, low-uncertainty measurements compliant with standardized test protocols. Designed specifically for quality control laboratories, electrode manufacturing facilities, and on-site inspection teams, the instrument delivers high reproducibility under variable environmental conditions while maintaining full adherence to international metrological practices for resistivity characterization.
Key Features
- High-current DC excitation source (35 A) optimized for low-resistance graphite samples (down to 2 µΩ), minimizing thermal drift and improving signal-to-noise ratio
- Four-terminal (Kelvin) measurement architecture with automatic polarity reversal to suppress thermoelectric EMF interference
- Micro-ohmmeter-grade resolution of 0.1 µΩ and accuracy certified to Class 0.5 per IEC 60584 and GB/T 7676 standards
- Embedded microcontroller-based firmware enabling fully automated measurement cycles, zero calibration, and real-time stability monitoring
- Ruggedized portable enclosure (4 kg total mass) with IP52-rated housing, shock-absorbing chassis, and integrated battery-backed memory for offline data retention
- Backlit LCD display supporting direct readout in µΩ, mΩ, and calculated resistivity (µΩ·m), with unit auto-scaling and overload protection
Sample Compatibility & Compliance
The GEST-122A.3 is validated for use with cylindrical or prismatic graphite electrodes (diameters ≥20 mm, lengths ≥100 mm), calcined coke, and sintered carbon blocks conforming to ASTM D3420, ISO 11713, and YB/T 120–1997 specifications. Its measurement methodology satisfies the core requirements of GB/T 24525–2009 (Determination of Electrical Resistivity of Carbon Materials) and GB/T 24521–2009 (Determination of Electrical Resistivity of Coke). All calibration procedures are traceable to national primary resistance standards maintained by the China National Institute of Metrology (NIM), and measurement uncertainty budgets comply with ISO/IEC 17025:2017 Annex A.2 for electrical resistance testing.
Software & Data Management
While the GEST-122A.3 operates as a standalone instrument, optional USB-C interface enables bidirectional communication with GuanCe’s PC-based QCData Manager v3.1 software (Windows 10/11 compatible). This application supports GLP-compliant audit trails—including operator ID, timestamped measurement logs, calibration history, and electronic signature fields—meeting FDA 21 CFR Part 11 requirements when deployed in regulated environments. Raw resistance values are exportable in CSV and XML formats; resistivity calculations automatically apply geometric correction factors based on user-input sample dimensions (cross-sectional area and length), with configurable unit preferences (µΩ·m, Ω·cm, or nΩ·m).
Applications
- Quality assurance of graphite electrodes used in electric arc furnaces (EAFs) and submerged arc furnaces (SAFs)
- In-process verification of green electrode baking uniformity and final graphitization degree
- Comparative evaluation of raw material batches (petroleum coke, needle coke, binder pitch) prior to extrusion
- Field verification of electrode integrity following transportation or storage-induced microcracking
- Research-grade correlation studies between resistivity, density, and flexural strength in carbon composites
- Supporting ISO 5755–2 compliance audits for refractory carbon components in metallurgical applications
FAQ
What standards does the GEST-122A.3 directly support?
It is fully aligned with GB/T 24525–2009, GB/T 24521–2009, and YB/T 120–1997 for carbon and coke resistivity testing.
Can the instrument measure resistivity without manual geometric input?
No—resistivity calculation requires user entry of sample cross-section and length; resistance measurement itself is geometry-independent.
Is external calibration required before first use?
Yes; initial calibration using NIST-traceable shunt resistors (e.g., 10 µΩ, 100 µΩ, 1 mΩ) is mandatory and documented in the Certificate of Conformance.
Does the device meet electromagnetic compatibility (EMC) requirements for industrial labs?
It complies with GB/T 18268.1–2010 (IEC 61326–1:2012) for EMC in laboratory and industrial environments.
What maintenance intervals are recommended for sustained accuracy?
Annual verification against certified reference resistors and biannual cleaning of current/voltage terminals with isopropyl alcohol are advised.
