Zuofei ZWH-3A Advanced Microprocessor-Controlled Water Bath

Overview

The Zuofei ZWH-3A is a dual-chamber microprocessor-controlled water bath designed for precise, stable, and reproducible temperature maintenance in laboratory environments. Utilizing a robust PID (Proportional-Integral-Derivative) feedback algorithm, the system continuously monitors and adjusts heating output to minimize thermal deviation—ensuring consistent thermal conditions critical for enzymatic assays, cell culture incubation, sample equilibration, dissolution testing, and calibration of temperature-sensitive instrumentation. Its dual 3 L stainless steel baths operate independently, enabling parallel experiments at identical or differential setpoints without cross-contamination or thermal interference. Engineered for long-term reliability in QC labs, academic research facilities, and pharmaceutical development settings, the ZWH-3A complies with fundamental thermal stability requirements outlined in ISO/IEC 17025 for equipment used in accredited testing laboratories.

Key Features

• Dual independent 3 L stainless steel baths formed via one-piece deep-drawn stamping—eliminating seam-induced corrosion and facilitating complete drainage and cleaning.
• Internal surfaces treated with PTFE-based anti-corrosion coating, providing enhanced resistance to aqueous reagents, buffer solutions, and mild organic solvents commonly used in biological and biochemical workflows.
• Exterior housing constructed from cold-rolled steel with matte-textured epoxy-polyester powder coating—offering mechanical durability, scratch resistance, and protection against ambient humidity-induced oxidation.
• High-resolution TFT color display with intuitive icon-driven interface—enabling real-time monitoring of setpoint, actual temperature, ramp status, and operational mode (e.g., constant temp, timer-based hold).
• Embedded solid-state heating assembly: aluminum-clad cast-in-place heating plates ensure uniform heat distribution across the entire bath floor, minimizing vertical and lateral thermal gradients (< ±0.5°C across bath volume at 37°C).
• Dual safety architecture: bimetallic overtemperature cut-off switch (mechanical backup) combined with optical liquid-level sensor—automatically deactivates heating if fluid level falls below operational threshold.

Sample Compatibility & Compliance

The ZWH-3A accommodates standard laboratory vessels including glass beakers (up to 1000 mL), conical flasks, test tube racks, and immersion circulators. Its open-bath configuration supports passive convection-based heating of samples in sealed or vented containers, making it suitable for ASTM D1500 (petroleum color standards), USP environmental conditioning, and ISO 8573-1 compressed air moisture testing protocols requiring stable aqueous thermal media. While not certified for IEC 61000-6-3 EMC compliance out-of-box, its low EMI design meets typical Class B laboratory electromagnetic compatibility expectations. The unit adheres to general electrical safety principles aligned with GB 4793.1–2007 (equivalent to IEC 61010-1) for laboratory electrical equipment.

Software & Data Management

The ZWH-3A operates as a standalone instrument with no proprietary software dependency. All parameter configuration—including target temperature, dwell time, auto-shutdown delay, and display brightness—is performed locally via the front-panel interface. Temperature logging is not internally stored; however, the unit features an analog 0–5 V DC output (±0.02 V resolution) compatible with external data acquisition systems (e.g., LabVIEW, MATLAB, or PLC-based SCADA) for continuous traceable recording. When integrated into GLP/GMP-regulated environments, users may implement manual logbooks or third-party electronic lab notebooks (ELNs) to document calibration history, daily performance verification, and maintenance events—supporting audit readiness per FDA 21 CFR Part 11 when paired with appropriate access controls and electronic signature workflows.

Applications

• Enzyme kinetics studies requiring strict thermal control during spectrophotometric assays (e.g., LDH, ALP, or amylase activity measurements).
• Pre-incubation of microbial culture media prior to pour plating or broth enrichment steps in microbiology QA/QC.
• Temperature-dependent solubility profiling of active pharmaceutical ingredients (APIs) under ICH Q5C stability guidelines.
• Calibration of digital thermometers, RTDs, and thermocouples using NIST-traceable reference standards immersed in stabilized bath media.
• Controlled thawing of cryopreserved cell lines and serum batches where rapid, non-oscillatory warming minimizes ice recrystallization damage.
• Supporting accelerated aging studies per ASTM F1980 for medical device packaging validation.

FAQ

Does the ZWH-3A support external temperature probe input for chamber monitoring?
No—the unit relies solely on its factory-calibrated internal Pt100 sensor located at the bath centerline. External probe integration is not supported.
Can both baths be programmed to different temperatures simultaneously?
Yes—each chamber has independent PID control circuits and dedicated setpoint interfaces, allowing asynchronous operation within the full range (ambient +5°C to 100°C).
Is the water bath compatible with circulating chillers for sub-ambient operation?
No—this is a heater-only system with no refrigeration capability or chiller port. It is not rated for cooling applications.
What is the recommended maintenance interval for optimal thermal accuracy?
We recommend quarterly verification using a calibrated reference thermometer and annual recalibration of the internal sensor by an accredited metrology provider.
Are replacement parts such as heating plates or control boards available directly from Zuofei?
Yes—Zuofei provides OEM spare parts including display modules, PID controllers, and heating assemblies under part numbers traceable to ZWH-3A hardware revision v2.1 and later.