OK Instruments OK-TH-81 Temperature and Humidity Controlled Chamber for Coating Testing

Overview

The OK Instruments OK-TH-81 Temperature and Humidity Controlled Chamber is an engineered environmental test system designed specifically for coating, paint, and surface treatment laboratories requiring precise, reproducible climate simulation. It operates on a dual-control principle—simultaneous regulation of air temperature and relative humidity via independent refrigeration, heating, and steam/humidification subsystems—enabling stable, programmable exposure conditions critical for evaluating coating behavior under defined climatic stress. Unlike general-purpose environmental chambers, the OK-TH-81 integrates structural and control features aligned with ASTM D4585, ISO 6270, GB/T 1740, and GB/T 13893 protocols, supporting both static conditioning and cyclic testing modes essential for industrial R&D, QC validation, and regulatory compliance in coatings manufacturing.

Key Features

• Stainless steel interior chamber (SUS304 grade) with seamless welded corners and corrosion-resistant finish—optimized for solvent vapor resistance and long-term exposure to aggressive coating formulations.
• Benchtop form factor with compact footprint (600 × 500 × 400 mm internal volume), accommodating standard test panels (100 × 150 mm and 150 × 300 mm) on adjustable stainless steel grid shelves.
• Air-cooled refrigeration system with high-efficiency scroll compressor (domestic OEM-grade), delivering reliable cooling performance across the full −40 °C to +150 °C range.
• Pt100 platinum resistance temperature sensors and capacitive humidity transducers ensure traceable measurement accuracy; calibrated per ISO/IEC 17025-compliant procedures.
• Large double-layer tempered glass observation window with integrated LED lighting—enables non-intrusive visual monitoring of film defects (blushing, bubbling, cracking, chalking) without compromising chamber stability.
• Intuitive 7-inch color touchscreen controller with multi-segment programmability, real-time data logging, and USB export functionality for audit-ready test records.

Sample Compatibility & Compliance

The OK-TH-81 accommodates coated metal, wood, plastic, and composite substrates—including ASTM D609 cold-rolled steel panels, ISO 1514 aluminum test plates, and custom-sized specimens up to 10 mm thickness. Its humidity control architecture meets the stringent requirements of continuous condensation testing (per ISO 6270-2 and GB/T 13893), maintaining ≥95 % RH at 40 °C with minimal drift. The chamber’s temperature uniformity (≤±2.0 °C) and humidity uniformity (≤±3.0 % RH) satisfy minimum acceptance criteria specified in ASTM D2247 (100 % RH immersion simulation) and GB/T 1865 (artificial climate aging). All operational parameters are documented in accordance with GLP principles, supporting traceability for internal QA audits and third-party certification submissions.

Software & Data Management

The embedded controller supports up to 100 user-defined test programs, each with up to 99 segments (ramp/soak cycles). Real-time temperature and humidity values are logged at configurable intervals (1–600 seconds), with timestamped CSV output via USB interface. Data files include operator ID, program name, start/stop timestamps, and deviation alerts—facilitating alignment with FDA 21 CFR Part 11 requirements when paired with institutional electronic signature policies. Optional RS485 or Ethernet communication modules enable integration into centralized LIMS or MES platforms for automated report generation and cross-lab data harmonization.

Applications

• Drying and curing kinetics analysis: Quantifying film formation rate, solvent evaporation profile, and crosslink density development under controlled T/RH gradients.
• Accelerated weathering pre-screening: Simulating tropical (40 °C / 95 % RH), desert (60 °C / 20 % RH), and freeze-thaw (−25 °C ↔ 60 °C) conditions to rank formulation robustness.
• Storage stability assessment: Validating shelf-life claims for waterborne acrylics, epoxy dispersions, and UV-curable systems under elevated humidity or sub-zero storage profiles.
• Defect root-cause analysis: Reproducing field-observed failures—e.g., amine blush in polyurethanes at >80 % RH, or surfactant leaching in high-humidity cure—under repeatable lab conditions.
• Regulatory conformance testing: Executing mandatory evaluations per ISO 12944 C2–C5 corrosion categories, EN 10169 coil coating specifications, and China’s JC/T 412.1–2018 building coating standards.

FAQ

Does the OK-TH-81 support continuous condensation testing per ISO 6270?
Yes—the chamber achieves and sustains ≥95 % RH at 40 °C using a steam-based humidification system with PID-controlled water level management and deionized water feed requirement.
What maintenance intervals are recommended for optimal sensor accuracy?
We recommend annual calibration by an ISO/IEC 17025-accredited laboratory; quarterly internal verification using NIST-traceable dry-well and humidity generator standards is advised for high-usage labs.
Can the chamber operate unattended for extended cyclic tests?
Yes—equipped with over-temperature, over-humidity, and compressor fault protection circuits, plus automatic restart after power recovery (with optional battery-backed clock and memory retention).
Is deionized water mandatory for humidification?
Yes—use of distilled or deionized water (conductivity <5 µS/cm) is required to prevent mineral deposition on ultrasonic transducers and steam nozzles, ensuring long-term humidification reliability.
How is airflow uniformity validated within the working zone?
Air distribution is optimized via rear-mounted centrifugal blower with adjustable baffle system; uniformity is verified during factory acceptance testing using 9-point thermohygrometric mapping per IEC 60068-3-5.