Memmert WNB/WNE Series Water and Oil Bath Circulators

Overview

The Memmert WNB and WNE series are precision-engineered water bath circulators, while the ONE series constitutes a dedicated high-temperature oil bath platform—each designed and manufactured entirely in Germany under strict ISO 9001-certified production protocols. These units operate on the principle of convective thermal equilibrium: uniform heat distribution is achieved via three-directional heating elements integrated into the bath chamber walls, eliminating reliance on external pumps and minimizing thermal gradients across the working volume. Unlike single-point heated alternatives, this architecture ensures rapid temperature ramp-up (<15 min from ambient to 95 °C in 20 L configuration), exceptional spatial homogeneity (±0.1 °C at 37 °C, typical), and long-term stability (±0.05 °C over 8 h). The WNB model employs a robust analog-digital hybrid PID controller optimized for routine applications such as paraffin melting or enzyme incubation; the WNE and ONE models integrate an adaptive fuzzy-PID algorithm that dynamically adjusts control parameters based on load mass, ambient drift, and thermal inertia—critical for GxP-compliant calibration workflows and materials testing per ASTM E220 or ISO 17025.

Key Features

• German-engineered, fully vertically integrated design—from PCB-level electronics to stainless-steel bath construction—ensuring traceability, firmware longevity, and field-serviceability.
• Dual-stage independent overtemperature protection: electromechanical relay activation at setpoint +10 °C, plus certified mechanical safety cutout (TB device) at 135 °C (WNB/WNE) or 230 °C (ONE), compliant with EN 61010-1:2019 safety requirements.
• Three-directional heating system delivers laminar, pump-free circulation—validated by DIN 12879-1 thermal mapping protocols—with no dead zones or localized hot spots.
• Intuitive rotary-push control interface with tactile feedback and anti-glare LCD display; patented ergonomic design reduces operator error during repetitive parameter entry.
• Comprehensive self-diagnostic suite monitors heater continuity, sensor integrity, relay function, and communication bus status—log entries stored in non-volatile memory for audit readiness.
• Programmable timing functions: delayed start, hold duration, automatic shutdown, and temperature pre-conditioning mode for sample equilibration prior to assay initiation.
• Optional flow-cooling module (for WNB10–45 and WNE10–45) enables active heat dissipation during extended high-temperature holds, extending thermal stability window beyond passive cooling limits.

Sample Compatibility & Compliance

These baths accommodate standard laboratory vessels—including glass beakers (up to Ø200 mm), metal sample holders, calibration blocks, and immersion probes—without requiring custom fixtures. All wetted surfaces use electropolished 1.4404 (AISI 316L) stainless steel, resistant to corrosion from aqueous buffers, glycerol-water mixtures, silicone oils, and mineral oils up to 200 °C. Units meet CE marking requirements under the Low Voltage Directive (2014/35/EU) and EMC Directive (2014/30/EU). For regulated environments, the WNE and ONE models support optional TWB electronic overtemperature limiter with adjustable threshold (20–220 °C), configurable via service mode—enabling alignment with FDA 21 CFR Part 11 data integrity expectations when paired with validated external logging systems. Documentation packages include Factory Acceptance Test (FAT) reports, material certificates (EN 10204 3.1), and EU Declaration of Conformity.

Software & Data Management

While standalone operation requires no software, Memmert provides optional PC connectivity via RS232 or USB-to-serial adapter (not included). The proprietary Memmert LabSoft software (Windows-compatible) enables remote parameter setting, real-time temperature graphing, event-triggered data export (CSV), and digital signature–secured protocol archiving. Audit trail functionality records all user actions—including setpoint changes, mode switches, and safety limit adjustments—with timestamps and operator IDs. When deployed in GLP or GMP laboratories, the system supports integration into enterprise LIMS platforms via Modbus RTU protocol (requires optional interface module). All firmware updates are digitally signed and verified upon installation to prevent unauthorized modification.

Applications

• Calibration of platinum resistance thermometers (PRTs), thermocouples, and digital temperature sensors per ISO/IEC 17025 Clause 6.5.2.
• Thermal aging studies of polymer films, adhesives, and composite laminates under controlled humidity-free conditions (e.g., automotive safety glass moisture absorption kinetics per SAE J2527).
• Pre-warming of reagents and solvents in molecular biology workflows where precise endothermic dissolution is required (e.g., agarose gel preparation).
• Heat treatment of metal calibration standards and reference materials prior to dimensional metrology.
• Stability testing of pharmaceutical excipients under accelerated conditions (ICH Q1A).
• Viscosity benchmarking of Newtonian fluids using capillary or rotational viscometers immersed directly in the bath medium.

FAQ

Are WNB/WNE baths suitable for use with flammable solvents?
No. These units are not explosion-proof and must only be operated with non-flammable, non-volatile media—water, glycerol-water mixtures, silicone oils, or mineral oils meeting flash point >200 °C specifications.
Can the WNE controller store multiple temperature programs?
Yes. Up to 10 independent multi-step profiles (ramp-hold-cooldown sequences) can be saved and recalled via the front panel interface.
Is the TB mechanical safety cutout replaceable in the field?
Yes. The TB device is a certified, self-contained bimetallic switch with documented lifecycle (≥10,000 cycles); replacement kits and torque-spec tools are available through authorized Memmert service partners.
Does the ONE oil bath require special ventilation?
While not mandated by regulation, continuous local exhaust is recommended when operating above 150 °C to mitigate long-term thermal degradation fumes from synthetic oils.
What validation documentation is supplied with each unit?
Each shipment includes a Certificate of Conformance, factory calibration report (traceable to PTB), and full electrical safety test record—available in English or German upon order specification.