Zuofei ZWH-5 Advanced Microprocessor-Controlled Water Bath

Overview

The Zuofei ZWH-5 is a precision-engineered microprocessor-controlled water bath designed for stable, uniform thermal conditioning of samples in laboratory and quality control environments. Operating on the principle of convective heat transfer via immersion in a temperature-regulated aqueous medium, the ZWH-5 delivers consistent thermal energy distribution across its 5-liter stainless-steel bath chamber. Its core architecture integrates a cast-in heating plate bonded directly to the bath floor—ensuring minimal thermal gradient (<0.4°C across the working volume at 37°C, per internal validation protocol) and rapid thermal equilibration. The system employs a digital PID algorithm with adaptive tuning, enabling dynamic response to load changes and ambient fluctuations while maintaining setpoint stability within ±0.3°C under steady-state conditions. Designed for continuous operation in ISO 17025-accredited labs and GMP-compliant QC workflows, the ZWH-5 meets fundamental requirements for thermal consistency in applications ranging from enzyme kinetics assays to material stability testing.

Key Features

• One-piece deep-drawn 304 stainless-steel bath tank with PTFE-coated interior surface—resistant to corrosion from saline, buffered, or mildly acidic solutions commonly used in biological and pharmaceutical protocols.
• Robust cold-rolled steel outer casing with matte epoxy powder coating—engineered to inhibit oxidation and withstand routine lab cleaning agents and mechanical abrasion.
• High-resolution 4.3-inch TFT color display with intuitive touch-sensitive interface—enabling real-time monitoring of setpoint, actual temperature, elapsed time, and system status without menu navigation latency.
• Dual independent safety systems: bimetallic overtemperature cutoff (activated at 105°C) and optical liquid-level sensor—automatically disabling heating if fluid volume falls below minimum operational threshold (≥3.2 L), preventing dry-run damage.
• Integrated circulation-free design optimized for static incubation; optional external recirculation port available upon request for integration with auxiliary chillers or external sample manifolds.

Sample Compatibility & Compliance

The ZWH-5 accommodates standard laboratory glassware including beakers (up to 1000 mL), test tubes (16 × 150 mm), cuvettes, and enzymatic reaction vessels. Its bath geometry supports simultaneous thermal conditioning of up to twelve 15-mL conical tubes or six 50-mL centrifuge tubes. The unit complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and conforms to EN 60529 IP20 ingress protection rating. While not certified to UL or CSA standards out-of-the-box, it satisfies foundational thermal performance criteria referenced in ASTM E2208–22 (Standard Practice for Calibration of Liquid-In-Glass Thermometers) and supports traceable calibration using NIST-traceable reference thermometers. Documentation packages include factory calibration report (at 25°C, 37°C, and 60°C) and conformity statement per China RoHS Directive (GB/T 26572–2011).

Software & Data Management

The ZWH-5 operates as a standalone instrument with no embedded data logging or remote connectivity. All parameter inputs and real-time readings are confined to the local TFT interface. For laboratories requiring audit-ready records, optional RS-232 serial output (with Modbus RTU protocol) enables integration into third-party SCADA or LIMS platforms—supporting timestamped temperature capture at user-defined intervals (1–60 s). When paired with validated software (e.g., LabVIEW-based acquisition modules or Eurotherm iTools), the device supports 21 CFR Part 11-compliant electronic records—including operator ID assignment, change history tracking, and digital signature capability—provided the host system implements appropriate access controls and audit trail mechanisms.

Applications

• Thermal pre-conditioning of reagents and standards prior to HPLC or GC analysis (e.g., mobile phase degassing at 40°C).
• Controlled-rate thawing of cryopreserved cell cultures and serum batches per ISO/TS 20387:2018 biobanking guidelines.
• Stability assessment of topical formulations under accelerated conditions (40°C/75% RH correlation studies).
• Enzyme activity profiling across physiological temperature ranges (e.g., 25–45°C for amylase or protease kinetics).
• Calibration verification of liquid-in-glass and digital thermometers against reference standards per ISO/IEC 17025 Clause 6.5.

FAQ

Does the ZWH-5 support external temperature probe input for chamber monitoring?
No—the unit relies exclusively on its factory-calibrated PT100 sensor embedded in the bath floor. External probe inputs are not supported.
Is the bath depth sufficient for full immersion of 15-cm culture tubes?
Yes—the effective liquid depth is 145 mm at nominal fill level (5 L), accommodating tubes up to 150 mm in length with ≥10 mm of headspace clearance.
Can the ZWH-5 be operated continuously for 72+ hours?
Yes—designed for unattended operation under Class II laboratory environmental conditions (15–30°C ambient, ≤70% RH); thermal management system includes duty-cycle modulation to prevent heater coil fatigue.
What maintenance is required to ensure long-term accuracy?
Biannual verification using a NIST-traceable thermometer is recommended; cleaning of the PTFE-coated bath surface with deionized water and lint-free cloth prevents residue buildup that may affect thermal contact uniformity.