Tianfeng TF-HX-8D Precision Refrigerated/Heating Circulating Bath

Overview

The Tianfeng TF-HX-8D is a high-stability, dual-mode refrigerated/heating circulating bath engineered for precision temperature control in analytical, pharmaceutical, and materials science laboratories. It operates on a closed-loop thermodynamic system combining a hermetically sealed air-cooled compressor with an electric heating element, enabling seamless transition between sub-zero and near-boiling operating conditions. The unit utilizes a high-efficiency evaporator designed according to large-volume thermal equilibrium principles, ensuring rapid cooling ramp rates and exceptional spatial temperature uniformity across the 8-liter working chamber. Its core function is to maintain setpoint stability within ±0.1 °C under dynamic load conditions—critical for applications such as viscometer calibration, spectrophotometer thermal stabilization, reaction kinetics studies, and reference standard conditioning.

Key Features

• Hermetically sealed, air-cooled compressor with imported refrigeration components, delivering robust low-temperature performance down to −40 °C while minimizing ambient heat dissipation.
• Dual circulation mode: internal recirculation for bath homogeneity; external pump-driven flow (via integrated outlet/inlet ports) for remote temperature control of auxiliary equipment—including rotary evaporators, condensers, or custom reaction vessels.
• Full stainless steel interior and work surface—electropolished for corrosion resistance, cleanability, and compliance with ISO 14644 cleanroom-compatible maintenance protocols.
• PID temperature controller with adaptive output tuning, minimizing overshoot and stabilizing setpoints rapidly after load changes or setpoint adjustments.
• Intuitive touch-sensitive soft-key interface with dual digital displays: one for real-time bath temperature, another for programmed timer functions (including delayed start and scheduled shutdown).
• Integrated safety architecture featuring dual independent thermal monitoring: primary over-temperature cutoff and secondary differential alarm triggered by ≥3 °C deviation between sensor reading and setpoint—both logged with timestamps for GLP audit trails.

Sample Compatibility & Compliance

The TF-HX-8D accommodates a broad range of sample containers—from standard 1-L glass jacketed reactors to multi-port PTFE-lined immersion probes—without compromising thermal fidelity. Its open-bath design allows direct placement of temperature-sensitive instrumentation (e.g., rheometers, densitometers) into the fluid medium. The unit meets CE marking requirements for electromagnetic compatibility (EMC Directive 2014/30/EU) and low-voltage safety (LVD Directive 2014/35/EU). While not certified to IEC 61010-1 Annex BB for explosive atmospheres, its stainless steel construction and sealed electronics render it suitable for general laboratory environments compliant with ISO/IEC 17025:2017 clause 6.4.3 (environmental condition control). Optional calibration certificates traceable to NIM (National Institute of Metrology, China) are available upon request for regulated QC workflows.

Software & Data Management

The TF-HX-8D operates as a standalone instrument with no proprietary software dependency. All operational parameters—including setpoint, actual temperature, elapsed time, and alarm status—are continuously displayed and retained in non-volatile memory during power interruption. For integration into networked lab infrastructures, analog 0–5 V or 4–20 mA process outputs (optional accessory) enable connection to SCADA systems or centralized data loggers compliant with ASTM E2500-22 (Good Automated Manufacturing Practice). Audit-ready event logging—including temperature excursions, alarm triggers, and manual parameter changes—is stored locally for ≥30 days and exportable via USB interface (firmware v2.1+), supporting FDA 21 CFR Part 11 compliance when paired with validated third-party electronic lab notebook (ELN) platforms.

Applications

• Calibration of temperature-dependent analytical instruments (e.g., HPLC column ovens, UV-Vis cuvette holders, DSC reference cells).
• Stabilization of laser sources and optical benches requiring sub-0.2 °C thermal drift suppression over 8-hour shifts.
• Controlled-rate cooling/heating of polymer melts during rheological characterization per ASTM D3835 and ISO 6721-10.
• Long-duration enzymatic assays where reaction velocity is highly sensitive to thermal fluctuations (e.g., ELISA incubation validation per CLSI EP23-A).
• Pre-conditioning of reference standards (e.g., certified viscosity oils, thermal conductivity fluids) prior to metrological verification.

FAQ

What is the maximum external flow rate supported in external circulation mode?
The built-in centrifugal pump delivers up to 15 L/min at ≤0.2 bar backpressure—sufficient for most single-stream applications; flow rate decreases linearly with increasing system resistance.
Can the bath operate continuously at −40 °C ambient temperature?
Yes, provided ambient humidity remains below 60% RH and ventilation clearance ≥100 mm is maintained on all sides; continuous operation at extreme setpoints may reduce compressor service interval by ~15% per 1,000 hours.
Is the temperature sensor calibrated to national standards?
The factory-installed Pt100 sensor is verified against NIM-traceable reference standards; optional UKAS-accredited calibration (±0.05 °C uncertainty) is available with certificate of conformance.
Does the unit support RS485 or Ethernet communication?
No native serial or network interface is included; however, analog output modules (0–5 V / 4–20 mA) can be retrofitted for PLC integration under engineering supervision.
What maintenance intervals are recommended for optimal long-term stability?
Compressor oil inspection every 2,000 operating hours; evaporator coil cleaning every 6 months in high-dust environments; full system performance verification annually using NIST-traceable dry-block calibrators.