Huake Instrument HK-3160SZ Automatic Acid Number Analyzer

Overview

The Huake Instrument HK-3160SZ Automatic Acid Number Analyzer is a fully integrated benchtop analytical system engineered for precise, reproducible determination of acid number (AN) in insulating oils—primarily transformer oil and turbine oil—according to the standardized potentiometric and colorimetric endpoint detection method specified in GB/T 7599–1987. This standard aligns closely with ASTM D974 (KOH titration using bromothymol blue, BTB) and IEC 62021-1 for insulating liquids. The instrument implements an automated BTB-based neutralization titration protocol: a fixed-volume aliquot of extraction solvent (typically toluene–isopropanol–water mixture) is delivered into the sample cup; a pre-weighed oil specimen (typically 10–20 g) is introduced; the mixture undergoes controlled magnetic stirring to extract acidic components; and titration is performed using standardized 0.02–0.05 mol/L potassium hydroxide in ethanol solution. Endpoint detection relies on a stable optical sensor system that monitors the spectral shift of BTB indicator—from yellow (pH < 6.0) to blue-green (pH ≈ 7.6), compensating for inherent oil color interference. The entire workflow—including reagent dispensing, agitation, titrant delivery, endpoint recognition, calculation, and result reporting—is executed without manual intervention.

Key Features

• Automated BTB neutralization titration with optical endpoint detection—eliminates subjective visual interpretation and ensures high inter-operator reproducibility
• Gas-displacement reagent delivery system for KOH ethanol titrant, replacing peristaltic pumps to improve volumetric accuracy and long-term calibration stability
• 7-inch high-resolution (800 × 480) capacitive touchscreen with dual-language UI (English/Chinese), supporting intuitive navigation and real-time status monitoring
• Sealed reagent handling architecture: proprietary solvent bottles with inert gas purge ports prevent CO₂ absorption and solvent evaporation during operation
• Integrated temperature regulation module maintains internal chamber at 30 °C ± 1 °C under ambient conditions below 15 °C, ensuring consistent reaction kinetics and endpoint sharpness
• Multi-sample capability: simultaneous batch processing of 1–6 samples with independent cup positioning and sequential auto-titration
• Comprehensive self-diagnostic routines including fluid path integrity checks, sensor response validation, and reagent level monitoring with audible/visual alerts
• Dual communication interfaces: 10/100 Mbps Ethernet (supporting DHCP, static IP, and remote configuration via web interface) and USB 2.0 host port for data export and firmware updates

Sample Compatibility & Compliance

The HK-3160SZ is validated for use with mineral-based, synthetic, and bio-based insulating oils meeting IEC 60296 specifications. It supports sample matrices with viscosity up to 100 mm²/s at 40 °C and water content ≤ 50 ppm. All measurement procedures comply with the metrological traceability requirements of ISO/IEC 17025:2017 for testing laboratories. Data integrity safeguards include audit-trail-enabled result storage (timestamped, operator-ID tagged, and immutable), consistent with GLP and GMP documentation expectations. While not FDA 21 CFR Part 11 certified out-of-the-box, the system’s electronic record architecture supports implementation of supplementary access controls and digital signature workflows required for regulated environments.

Software & Data Management

Embedded firmware stores up to 1,000 complete test records—including raw titration curves, endpoint confirmation flags, calculated acid number (mg KOH/g), sample ID, operator ID, date/time stamp, and environmental parameters (ambient temperature, humidity). Records are retrievable by chronological filter or custom search criteria via touchscreen or exported in CSV format via USB drive. No proprietary software installation is required for basic operation; however, optional PC-based HuakeLab Suite (v3.2+) enables advanced statistical analysis (e.g., trend charts, RSD calculation, QC charting per ASTM E2554), LIMS integration via HL7 or ASTM E1384, and automated report generation compliant with ISO 17025 clause 7.8.2.

Applications

• Condition monitoring of power transformer insulating oil in substation maintenance programs
• Quality assurance testing of new and reclaimed turbine oils in thermal power plants
• Routine acid number verification during oil reclamation and regeneration processes
• Research-grade oxidation stability assessment in lubricant development labs
• Third-party certification testing for ISO 8502-2 and ASTM D664-compliant laboratories

FAQ

What titration method does the HK-3160SZ employ?
It implements the standardized BTB (bromothymol blue) colorimetric endpoint titration method per GB/T 7599–1987 and ASTM D974, using optical detection rather than manual visual endpoint judgment.
Can the instrument be used for non-oil samples such as biodiesel or organic acids?
No—it is specifically calibrated and validated for petroleum-based insulating oils; application to other matrices requires full method validation per ISO 17025 Annex B.
Is the reagent delivery system compatible with alternative titrants like NaOH in methanol?
Only KOH in ethanol (0.02–0.05 mol/L) is supported; solvent compatibility and endpoint pH range are optimized for this specific system.
How is data security and traceability ensured?
All measurements are timestamped, operator-tagged, and stored with checksum-verified integrity; USB exports retain full metadata and cannot be altered without breaking file structure.
Does the analyzer require annual recalibration?
Yes—annual verification of photometric sensor linearity, titrant delivery volume accuracy (via gravimetric check), and temperature control stability is recommended per ISO/IEC 17025 Clause 6.4.