Zuofei ZWH-2 Advanced Microprocessor-Controlled Constant-Temperature Water Bath

Overview

The Zuofei ZWH-2 is a precision-engineered, microprocessor-controlled constant-temperature water bath designed for reliable thermal stabilization of samples in analytical, biochemical, pharmaceutical, and quality control laboratories. Operating on the principle of convective heat transfer via a fully immersed, thermostatically regulated water medium, the ZWH-2 delivers stable, uniform temperature environments essential for enzyme assays, cell culture incubation, sample thawing, dissolution testing, and calibration of temperature-sensitive instrumentation. Its compact footprint and optimized thermal architecture make it particularly suitable for benchtop use in ISO 17025-accredited labs, GLP-compliant R&D settings, and routine QC workflows where reproducibility, safety, and long-term operational consistency are non-negotiable.

Key Features

• One-piece deep-drawn stainless steel bath vessel with PTFE-coated interior surface—ensuring exceptional corrosion resistance, ease of cleaning, and compatibility with aqueous buffers, saline solutions, and mild organic solvents.
• Robust cold-rolled steel outer housing with matte-finish powder coating—providing mechanical durability, scratch resistance, and long-term protection against ambient moisture and laboratory spills.
• Advanced PID temperature control algorithm implemented via embedded microprocessor—enabling rapid thermal equilibration (<15 min from ambient to 37°C), minimal temperature overshoot (<0.2°C), and steady-state stability within ±0.3°C over 24-hour operation.
• High-resolution 4.3-inch TFT color touchscreen interface—supporting intuitive parameter navigation, real-time temperature graphing, setpoint adjustment in 0.1°C increments, and dual-language UI (English/Chinese) firmware.
• Dual independent safety systems: (1) Bimetallic overtemperature cut-off switch (trip point: 105°C), and (2) optical liquid-level sensor—automatically disabling heating if water volume falls below minimum operational level (≥1.2 L), preventing dry-run damage.
• Integrated cast-in-place heating plate—thermally bonded to the bath base for maximal heat transfer efficiency, minimized thermal gradients (<0.2°C across 2L volume at 37°C), and extended heater service life.

Sample Compatibility & Compliance

The ZWH-2 accommodates standard laboratory glassware including beakers (up to 1000 mL), test tubes (12–16 mm OD), cuvettes, and small-volume reaction vessels. Its 2 L working volume supports simultaneous temperature conditioning of multiple samples without compromising uniformity. The unit complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements for EMC (EN 61326-1) and low-voltage directives. While not certified for Class I Division 1 hazardous locations, its sealed electronics and non-sparking design render it appropriate for general-purpose wet-lab environments under ISO/IEC 17025 and FDA-regulated facilities operating under 21 CFR Part 11–aligned SOPs.

Software & Data Management

The ZWH-2 operates as a standalone instrument with no mandatory software dependency; however, optional RS-232 serial output enables connection to external data loggers or LIMS-compatible acquisition systems. Logged parameters—including real-time bath temperature, setpoint, elapsed time, and fault codes—are timestamped and exportable in CSV format. Firmware supports audit trail functionality (enabled via password-protected admin mode), recording user-initiated changes to setpoints or system configurations—critical for GxP environments requiring traceability per ALCOA+ principles. No cloud connectivity or proprietary drivers are required; communication protocols adhere to standard ASCII command sets compatible with LabVIEW, MATLAB, and Python-based automation frameworks.

Applications

• Pharmaceutical: USP dissolution apparatus water baths, stability study sample conditioning (25°C/60% RH reference baths), and viscosity standardization prior to rheometry.
• Biotechnology: Enzyme kinetic assays (e.g., LDH, ALP) requiring strict thermal control at 37°C; DNA hybridization and restriction digest incubations.
• Food & Beverage: AOAC 986.18 fat extraction water baths, microbiological media melting and holding (ISO 6887-1), and sensory evaluation sample equilibration.
• Academic Research: Calibration of thermocouples and RTDs; thermal expansion coefficient measurements; and solvent pre-warming in synthetic chemistry workflows.
• Industrial QA/QC: Paint viscosity bath conditioning (ASTM D1200), polymer melt index auxiliary heating, and adhesive curing profile development.

FAQ

What is the minimum water volume required for safe operation?
The optical liquid-level sensor activates protection at ≤1.2 L; operation below this volume will disable heating and display “LO” on the screen.
Can the ZWH-2 be used with circulating chillers for sub-ambient applications?
No—the ZWH-2 is a heating-only bath with no refrigeration capability or external circulation port; it is not designed for cooling or external pump integration.
Is the PTFE coating resistant to sodium hydroxide or nitric acid solutions?
Yes—the fluoropolymer layer withstands short-term exposure to ≤10% NaOH and ≤30% HNO₃; prolonged immersion in strong oxidizers is not recommended.
Does the unit support external temperature probe input for sample-specific monitoring?
No—temperature sensing is internal only (PT1000 sensor embedded in bath wall); no auxiliary probe port is provided.
What is the typical warm-up time from 25°C to 65°C?
Approximately 18 minutes under standard load conditions (2 L deionized water, ambient lab temperature 22°C).