MEMMERT WNB22 Water Bath
| Brand | MEMMERT |
|---|---|
| Origin | Germany |
| Model | WNB22 |
| Instrument Type | Circulating Water Bath |
| Internal Volume | 22 L |
| Temperature Range | 10 °C to 95 °C (with optional boiling mode at 100 °C) |
| Temperature Stability | ±0.1 °C (typical, at 37 °C, load-free) |
| Temperature Resolution & Setpoint Accuracy | 0.1 °C |
| Control System | PID with self-diagnostic function |
| Sensor | Dual 4-wire Pt100 (E-type), single 4-wire Pt100 (B-type) |
| Overtemperature Protection | Triple-stage (E-type) / Dual-stage (B-type) |
| Timer Range | B-type: 1 min – 99 h 59 min |
| E-type | 1 min – 999 h |
| Power Rating | 2000 W |
| Construction | Stainless steel inner bath and outer housing (AISI 304) |
| Certifications | CE, tested to IEC 61010-1 for laboratory safety |
Overview
The MEMMERT WNB22 is a precision-engineered circulating water bath designed for stable, reproducible thermal control in demanding laboratory environments. Based on resistive heating and forced convection via an integrated internal circulation pump, the WNB22 maintains uniform temperature distribution across its 22 L stainless steel bath chamber—critical for applications requiring minimal thermal gradients, such as enzyme incubation, sample equilibration, reagent warming, and controlled reaction kinetics. Its operational range spans from 10 °C (minimum setpoint ≥5 K above ambient) to 95 °C, with a dedicated 100 °C boiling mode for rapid solvent removal or sterilization support. The unit complies with IEC 61010-1 safety standards and carries CE marking, confirming conformity with EU directives for electrical equipment used in laboratories.
Key Features
- Precision temperature regulation using digital PID control with real-time self-diagnostic capability and LED display showing both setpoint and actual temperature (0.1 °C resolution).
- High-accuracy temperature sensing: single 4-wire Pt100 probe (B-type) or dual independent 4-wire Pt100 probes (E-type) for redundancy and improved spatial representativeness.
- Robust overtemperature protection architecture: B-type features dual safeguards—electronic cutoff at +10 °C above setpoint and mechanical TB thermostat activation at +30 °C above bath’s maximum rated temperature; E-type adds user-configurable electronic overtemperature limit (TWW/TWB) for application-specific safety thresholds.
- Programmable timer functionality: B-type supports start-delay-hold sequences; E-type extends scheduling flexibility with time-dependent hold profiles where temperature may vary as a function of elapsed runtime.
- Corrosion-resistant AISI 304 stainless steel construction for both inner bath and external housing—ensuring long-term durability, cleanability, and compatibility with aqueous and mildly aggressive media.
- Integrated internal circulation pump enables homogeneous thermal distribution without external tubing or risk of leakage—ideal for closed-system protocols under GLP/GMP conditions.
Sample Compatibility & Compliance
The WNB22 accommodates standard laboratory glassware—including Erlenmeyer flasks (100–500 mL), test tubes (14.5–32 mm diameter), and custom vessels—via interchangeable accessories such as conical flask holders, adjustable-height racks, and modular tube stands. Optional flat or gabled lids minimize evaporation and support integration with shaker modules (M00 series). All configurations maintain full traceability under ISO/IEC 17025-compliant workflows. The device meets essential requirements of Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and its design facilitates audit readiness for FDA 21 CFR Part 11–aligned environments when paired with MEMMERT’s optional data logging software.
Software & Data Management
While the WNB22 operates autonomously via front-panel controls, it is fully compatible with MEMMERT’s optional PC-based software suite for remote monitoring, parameter logging, and electronic record generation. Data export supports CSV and XML formats, enabling integration into LIMS or ELN platforms. Audit trails—including operator ID, timestamped setpoint changes, alarm events, and calibration history—can be configured to satisfy ALCOA+ principles. Firmware updates are delivered via USB interface, ensuring continued compliance with evolving regulatory expectations.
Applications
- Biomedical sample preparation: DNA/RNA extraction buffer equilibration, antibody dilution warming, cell culture medium pre-warming.
- Pharmaceutical QC testing: dissolution medium conditioning per USP , stability study sample holding at defined temperatures.
- Chemical synthesis: controlled hydrolysis, esterification, and reflux support (when used with condenser assemblies).
- Materials science: polymer solubilization, viscosity reference standard conditioning prior to rheometry.
- Environmental testing: BOD incubation support, extractant temperature stabilization for EPA Method 3510C.
FAQ
What is the difference between the B-type and E-type controllers?
The B-type offers basic PID control with dual overtemperature protection and a 99 h 59 min timer. The E-type adds a second Pt100 sensor, configurable electronic overtemperature limit (TWW/TWB), extended 999 h timer, and time-variable temperature programming.
Can the WNB22 be used for oil baths?
No—the WNB22 is specifically engineered for aqueous media. For oil-based applications, MEMMERT’s OB22 oil bath (identical dimensions, optimized heater design and thermal insulation) is recommended.
Is external circulation possible?
The WNB22 provides only internal recirculation. External pumping requires a separate circulation chiller or bath circulator (e.g., MEMMERT Heto HC series) with compatible inlet/outlet ports.
Does the unit include a lid?
Yes—a flat stainless steel lid (L0) is supplied as standard. A gabled lid (L1) is available for enhanced evaporation control and optional shaker integration.
How is calibration verified?
Users may perform in-house verification using NIST-traceable reference thermometers inserted into designated calibration ports. Factory calibration certificates (DIN EN ISO/IEC 17025) are available upon request.
