Hanuo GH-1 High-Precision Constant-Temperature Water Bath Circulator

Overview

The Hanuo GH-1 High-Precision Constant-Temperature Water Bath Circulator is an engineered thermal management platform designed for laboratories requiring tight temperature control across a broad operational range (–40 °C to +100 °C). Unlike basic immersion baths, the GH-1 employs a dual-mode refrigeration-heating system with active heat exchange and high-efficiency compressors, enabling stable setpoint maintenance without external chiller dependency. Its core thermodynamic architecture follows ISO/IEC 17025-aligned thermal equilibrium principles—utilizing forced convection via integrated circulation pumps and optimized bath geometry to minimize radial and axial thermal gradients. The device serves as both a standalone temperature source and a closed-loop thermal interface for external apparatus (e.g., viscometers, spectrophotometer cells, reaction calorimeters), meeting the stringent thermal stability demands of analytical validation, material characterization, and process development workflows.

Key Features

• Compact benchtop design (250 × 200 × 400 mm) with minimized footprint—ideal for space-constrained analytical labs and QC environments.
• Dual-mode thermal control: seamless transition between refrigeration and heating within a single unit; no manual coolant swaps or auxiliary chillers required.
• PID-based digital temperature regulation with auto-tuning capability ensures rapid stabilization (<15 min from ambient to 80 °C) and long-term drift < ±0.01 °C over 24 h (verified per ASTM E1137).
• Dual LED display showing real-time bath temperature and user-defined setpoint simultaneously, with 0.01 °C resolution and tactile membrane keypad interface.
• Bi-directional circulation system: internal recirculation maintains uniformity (±0.02 °C across 10 L volume); external port supports 0.5–2.0 L/min flow rate for remote thermal coupling (e.g., jacketed reactors, column ovens).
• Optional tap-water cooling module enables forced ramp-down from elevated temperatures—critical for exothermic reaction quenching and thermal cycling protocols in polymerization or catalysis studies.
• Stainless steel 304 bath chamber with corrosion-resistant insulation and over-temperature/low-fluid-level safety cutoffs compliant with IEC 61010-1.

Sample Compatibility & Compliance

The GH-1 accommodates aqueous solutions, silicone oils (up to 200 °C viscosity grade), and low-volatility organic heat transfer fluids. Its sealed circulation path prevents evaporation loss and cross-contamination during extended operation. The unit meets CE marking requirements and conforms to ISO 17025 clause 5.4.2 for equipment suitability in accredited testing laboratories. All temperature calibration points are traceable to NIST-certified reference thermometers (±0.005 °C uncertainty), and optional factory calibration reports include full uncertainty budgets. For regulated environments, audit-ready temperature logging (via RS232/USB) supports 21 CFR Part 11-compliant electronic records when paired with validated third-party software.

Software & Data Management

The GH-1 includes standard analog/digital I/O for integration into LabVIEW, MATLAB, or SCADA systems. An optional PC interface kit enables real-time data streaming at 1 Hz sampling, time-stamped temperature logs (CSV export), and programmable ramp-hold profiles. Built-in non-volatile memory retains up to 100 user-defined programs with password protection. All firmware updates follow secure signed-package protocols, and event logs record operator actions, alarm triggers, and thermal deviations—supporting GLP/GMP documentation requirements for method validation and equipment qualification (IQ/OQ/PQ).

Applications

• Calibration of temperature-sensitive instrumentation (thermocouples, RTDs, infrared sensors) per ISO/IEC 17025 Section 6.4.
• Controlled-temperature sample conditioning prior to HPLC injection, DSC analysis, or rheological measurement.
• Thermal stability testing of pharmaceutical formulations (e.g., accelerated stability per ICH Q1A).
• Constant-temperature environment for electrochemical cell testing, semiconductor wafer probing, and optical alignment setups.
• Reaction temperature control in small-scale batch synthesis where precise exotherm management is critical.
• Reference bath for inter-laboratory proficiency testing under ILAC-G8 guidelines.

FAQ

What is the maximum allowable operating temperature when using water versus silicone oil?
Water is rated up to 95 °C (to prevent boiling and cavitation); silicone oil extends the upper limit to 200 °C (requires GH-1A variant with upgraded seals and pump motor).
Does the GH-1 support external temperature feedback from a probe placed in the sample vessel?
Yes—the unit accepts optional PT100 input (0–100 Ω range) for cascade control mode, enabling sample-point rather than bath-point regulation.
Is the external circulation port compatible with standard laboratory tubing sizes?
It features dual 1/4″–28 UNF threaded ports accepting Tygon® R-3603, Viton®, or PTFE-lined tubing (ID: 4–6 mm).
How often does the system require recalibration for GLP compliance?
Annual verification against NIST-traceable standards is recommended; certificates include as-found/as-left data and measurement uncertainty per ISO/IEC 17025 Annex A.
Can the GH-1 be integrated into a building management system (BMS)?
Via optional Modbus RTU (RS485) interface, it supports read-only status reporting (temperature, alarm state, pump status) and setpoint override commands.