Hanuo HNF-3A Triple-Independent Zone Constant-Temperature Water Bath

Overview

The Hanuo HNF-3A Triple-Independent Zone Constant-Temperature Water Bath is a precision-engineered thermal platform designed for simultaneous multi-condition incubation, sample conditioning, and auxiliary heating in academic, pharmaceutical, and quality control laboratories. Unlike single-zone water baths, the HNF-3A integrates three physically isolated stainless-steel baths—each with dedicated PID-based temperature control circuitry—enabling concurrent operation at three distinct setpoints within the ambient-to-100 °C range. Its heating-only architecture (no refrigeration or forced circulation) ensures stable, low-maintenance thermal environments suitable for applications requiring gentle, uniform conductive heating—such as reagent equilibration, enzyme activation studies, dissolution media pre-warming, and low-risk sterilization by boiling. The unit operates on fundamental principles of resistive heating and proportional-integral-derivative (PID) feedback control, delivering ±0.3 °C temperature stability across all zones under steady-state conditions, verified per ISO/IEC 17025 traceable calibration protocols.

Key Features

• Three independent stainless-steel baths (110 × 100 × 130 mm each), sealed against cross-contamination and corrosion
• Dedicated digital LED display and push-button interface per zone for real-time temperature monitoring and setpoint adjustment
• PID temperature controller with auto-tuning capability, minimizing overshoot and optimizing recovery time after load changes
• Over-temperature cut-off protection (mechanical safety thermostat) integrated into each heating channel
• Robust chassis construction with heat-insulated housing and non-slip rubber feet for benchtop stability
• Compliance with IEC 61010-1 for electrical safety in laboratory environments; meets GB/T 28908–2012 performance requirements for constant-temperature baths

Sample Compatibility & Compliance

The HNF-3A accommodates standard laboratory glassware including beakers (up to 500 mL), test tubes, flasks, and immersion probes—provided vessel height does not exceed 120 mm to ensure full submersion without overflow. It supports routine QC procedures aligned with USP , ISO 13485, and GLP documentation workflows when paired with external loggers for audit-ready temperature records. While not certified for GMP manufacturing environments, its design enables reproducible thermal conditioning compliant with ASTM E2252-19 (Standard Practice for Calibration of Liquid-in-Glass Thermometers) and supports validation activities under FDA 21 CFR Part 11 when used with validated data capture systems.

Software & Data Management

The HNF-3A operates as a standalone analog-digital hybrid instrument with no embedded software or network interface. Temperature logging requires external Class A platinum resistance thermometers (PRTs) connected to compliant data acquisition hardware (e.g., Omega OM-DAQPRO-5300). All three zones provide analog voltage outputs (0–5 V DC) proportional to measured temperature, enabling integration with SCADA platforms or LIMS via optional signal conditioners. For regulatory traceability, users are advised to implement manual log sheets or electronic lab notebooks (ELNs) that record setpoint, actual temperature (per zone), duration, operator ID, and environmental conditions—consistent with ALCOA+ data integrity principles.

Applications

• Simultaneous thermal conditioning of multiple reagent batches at differentiated setpoints (e.g., 37 °C for cell culture media, 60 °C for viscosity standard equilibration, 95 °C for DNA denaturation controls)
• Boiling-point sterilization of non-critical lab tools (forceps, spatulas) using open-bath operation at 100 °C
• Supporting gravimetric moisture analysis by pre-heating desiccators or sample pans
• Stabilizing reaction vessels during slow hydrolysis or esterification processes where precise, non-agitated heating is required
• Calibration support for liquid-in-glass thermometers and RTDs using fixed-point reference baths

FAQ

Does the HNF-3A support cooling or refrigeration?

No. It is a heating-only device with no thermoelectric or compressor-based cooling capability.
Can the three baths be operated at identical temperatures simultaneously?

Yes—each zone is fully independent, allowing synchronized or divergent setpoints.
Is external water circulation required for uniformity?

No. The design relies on natural convection; however, for enhanced homogeneity in viscous or high-volume samples, users may introduce low-speed magnetic stirrers compatible with bath dimensions.
What maintenance is recommended for long-term reliability?

Monthly descaling with 5% acetic acid solution (for hard-water regions), annual verification of PID tuning parameters, and biannual inspection of heater element continuity using a multimeter.
Is the unit suitable for oil bath operation?

Not recommended. The stainless-steel bath geometry and heater wattage density are optimized for aqueous media; silicone oil or mineral oil use may cause localized overheating and premature element failure.