Hanuo HN-020TD-II Transparent Glass Low-Temperature Circulating Bath

Overview

The Hanuo HN-020TD-II Transparent Glass Low-Temperature Circulating Bath is an engineered thermal management system designed for precision temperature control in analytical, synthetic, and biophysical laboratories. Utilizing a dual-mode thermoelectric/compressor-based refrigeration and resistive heating architecture, the unit maintains stable setpoint temperatures across its full operational range of 0 °C to 100 °C. Its defining feature—a triple-sided transparent borosilicate glass bath chamber—enables real-time visual monitoring of sample behavior, including phase transitions, colorimetric changes, fluid dynamics, and exothermic/endothermic reaction progression without compromising thermal integrity. Unlike conventional opaque stainless-steel baths, this design supports process validation, kinetic observation, and method development where optical access is essential—for example, during UV-Vis spectroscopy cell calibration, enzymatic assay optimization, or polymer gelation studies. The system operates as a closed-loop internal circulation bath, eliminating external plumbing requirements while ensuring uniform thermal distribution (±0.05 °C stability) throughout the 18 L working volume.

Key Features

• Triple-sided optical-grade borosilicate glass construction for unobstructed visualization of samples and thermal media
• PID-controlled digital temperature regulation with 0.01 °C display resolution and programmable ramp/soak profiles
• Dual-mode thermal actuation: high-efficiency compressor-based cooling combined with precision resistive heating elements
• Integrated internal recirculation pump delivering laminar flow and minimizing thermal stratification
• Compact desktop footprint (W × D × H ≈ 300 × 250 × 450 mm) optimized for space-constrained lab benches and fume hood integration
• Over-temperature, low-level, and dry-run protection circuits compliant with IEC 61010-1 safety standards
• RS232 communication interface supporting remote parameter setting and temperature logging via third-party software

Sample Compatibility & Compliance

The HN-020TD-II accommodates a broad spectrum of sample vessels—including standard 10–50 mL cuvettes, 100–500 mL jacketed reactors, immersion probes, and reference thermometer calibration fixtures—within its 250 mm × 200 mm × 350 mm working chamber (depth-adjustable via optional riser kits). It is validated for use with water, ethylene glycol/water mixtures, silicone oils (up to 100 °C), and low-volatility heat transfer fluids. The unit meets general requirements for ISO/IEC 17025-accredited calibration labs when employed in thermometer verification protocols per ASTM E77 and ISO 17034. Its sealed glass enclosure and non-corrosive wetted materials (PTFE-coated impeller, 316 stainless-steel heater core) ensure compatibility with mildly aggressive reagents used in pharmaceutical QC and fine chemical synthesis.

Software & Data Management

While the HN-020TD-II operates autonomously via its front-panel interface, its RS232 port enables bidirectional communication with host systems running LabVIEW, MATLAB, or custom Python-based data acquisition scripts. Temperature setpoints, actual readings, and alarm status are exportable as CSV or ASCII time-series logs. When integrated into networked lab infrastructure, the device supports basic audit trail functionality—including timestamped parameter changes and error event logging—aligned with foundational GLP documentation practices. Though not natively 21 CFR Part 11 compliant, its deterministic control loop and hardware-based temperature lockout facilitate qualification under GMP Annex 15 for non-critical process support applications.

Applications

• Calibration and verification of liquid-in-glass thermometers, RTDs, and thermocouples against NIST-traceable references
• Temperature-controlled spectroscopic measurements requiring optical access and thermal stability (e.g., CD, fluorescence, FTIR)
• Enzyme kinetics and protein folding studies where reaction progress is monitored visually or via inline sensors
• Heat transfer coefficient determination in microfluidic devices and lab-on-chip platforms
• Controlled crystallization and polymorph screening in early-phase API development
• Thermal preconditioning of electronic components prior to environmental stress testing

FAQ

What temperature accuracy can be achieved with the HN-020TD-II under standard operating conditions?
When stabilized at 25 °C using deionized water and allowed ≥30 minutes equilibration, the unit achieves ±0.05 °C stability over 2 hours (measured with a calibrated Pt100 probe at three spatial locations). Accuracy relative to ITS-90 is ±0.1 °C after factory calibration.
Is external circulation possible with this model?
No—the HN-020TD-II is configured exclusively for internal recirculation. For external loop applications, consider the HN-020TD-II-EXT variant with auxiliary pump port and pressure-rated fittings.
Can the bath operate continuously at 0 °C in ambient environments above 30 °C?
Yes, provided adequate ventilation around the rear condenser grille and ambient humidity remains below 60% RH. Continuous sub-ambient operation may reduce compressor service life; scheduled duty cycles are recommended for extended low-temperature use.
What maintenance intervals are specified for long-term reliability?
Biannual inspection of coolant level, pump impeller integrity, and condenser coil cleanliness is advised. Annual recalibration of the internal Pt100 sensor against a certified reference is recommended for metrologically sensitive applications.