Ailun AC-10 Air-Cooled COD Digestion System

Overview

The Ailun AC-10 Air-Cooled COD Digestion System is a precision-engineered thermal digestion platform designed for compliant execution of the dichromate-based chemical oxygen demand (COD) assay per ISO 6060, ASTM D1252, and EPA Method 410.1. Unlike conventional water-cooled reflux apparatuses, the AC-10 employs forced-air condensation technology to achieve efficient vapor return without external cooling water supply—eliminating plumbing dependencies, reducing laboratory infrastructure load, and minimizing operational hazards associated with boiling acid mixtures under reflux. The system operates on the principle of controlled, uniform thermal oxidation of organic matter in aqueous samples using acidic potassium dichromate (K₂Cr₂O₇) under strongly acidic (H₂SO₄) conditions at elevated temperatures (typically 150–165 °C for standard 2-hour digestion). Its single-zone aluminum heating block ensures rapid thermal equilibration and spatial temperature homogeneity across all 12 sample positions, directly supporting reproducible redox reaction kinetics essential for traceable COD quantification.

Key Features

• Air-cooled reflux design eliminates need for tap water or recirculating chillers—reducing utility consumption by >90% versus traditional water-condenser systems
• Single high-mass aluminum heating block with PID-controlled solid-state relay delivers ±1 °C thermal stability across full 32–399 °C operating range
• Programmable digital timer with ±0.1 s accuracy over 10-minute intervals supports strict adherence to method-defined digestion durations (e.g., 2 h @ 150 °C per ISO 6060)
• Compact footprint (280 × 220 × 160 mm) and low power draw (P_max = 1.2 kW) enable deployment in shared lab spaces or mobile environmental testing units
• Corrosion-resistant chamber housing and PTFE-coated sample vial supports ensure long-term reliability during repeated exposure to hot H₂SO₄/K₂Cr₂O₇ reagents
• Front-panel LED interface with independent temperature and time setpoints allows intuitive method recall and operator-independent setup

Sample Compatibility & Compliance

The AC-10 accommodates standard 17 mL borosilicate glass digestion vials (e.g., EPA-compliant 16 × 100 mm tubes), enabling direct integration with spectrophotometric or titrimetric COD quantification workflows. Each batch processes 12 samples simultaneously with total volumetric capacity of 204 mL—optimized for routine wastewater, surface water, and industrial effluent screening. The system meets functional requirements for GLP-compliant environmental laboratories conducting COD analysis under ISO/IEC 17025:2017 accreditation. While the instrument itself does not carry CE or UL certification, its operational parameters align with safety thresholds defined in IEC 61010-1 for laboratory electrical equipment. Documentation packages include calibration certificates for temperature and timer subsystems traceable to national standards (CNAS-accredited calibration).

Software & Data Management

The AC-10 operates as a standalone hardware platform with no embedded firmware or network connectivity. All operational parameters—including set temperature, digestion duration, and start timestamp—are manually entered via front-panel controls and retained only during active run cycles. For laboratories requiring audit-ready records, integration with external LIMS or ELN systems is achieved through manual entry of instrument logs or optional RS-232 data logging adapters (sold separately). Timer accuracy (±0.1 s over 10 min) satisfies minimum traceability requirements for FDA 21 CFR Part 11–aligned environments when paired with procedural documentation of operator identity, sample IDs, and calibration status.

Applications

• Routine COD determination in municipal wastewater treatment plants (influent, effluent, sludge supernatant)
• Industrial process water monitoring for textile, pharmaceutical, food & beverage, and pulp & paper sectors
• Environmental field labs performing on-site compliance testing per local discharge permits
• Educational laboratories teaching standardized wet-chemistry oxidation methods
• Research studies requiring high-throughput screening of organic loading in natural waters or bioreactor effluents

FAQ

Does the AC-10 support programmable multi-step temperature ramps?

No—the AC-10 provides single-setpoint temperature control only. It is engineered for fixed-temperature digestion protocols such as ISO 6060 (150 °C) or ASTM D1252-B (165 °C).
Can it be used for total phosphorus or total nitrogen digestion?

Not without validation. While the thermal range exceeds typical persulfate digestion requirements (e.g., 120 °C for TP), the air-condensation geometry is optimized specifically for dichromate reflux chemistry; users must perform method-specific verification per ISO 15681-1 or EN 15972.
Is the heating block interchangeable with other Ailun models?

No—block geometry, thermocouple placement, and mounting interface are model-specific and not cross-compatible.
What maintenance is required for long-term accuracy?

Annual verification of temperature uniformity across all 12 positions using NIST-traceable calibrated thermometers is recommended; cleaning of air ducts and condenser fins every 200 runs prevents thermal drift.
Does the unit include digestion vials or reagents?

No—vials, K₂Cr₂O₇/H₂SO₄ reagents, and post-digestion analysis consumables must be sourced separately per analytical method requirements.