DRETOP EWS-16 Electric Stirring Water Bath

Overview

The DRETOP EWS-16 Electric Stirring Water Bath is an engineered solution for laboratories requiring simultaneous precise temperature control and mechanical agitation in aqueous or low-viscosity media. Based on resistive heating and PID-regulated thermal feedback, the unit maintains a stable thermal environment across six independent sample positions without fluid circulation—making it suitable for applications where minimal convection-induced disturbance is preferred. Its design conforms to fundamental laboratory safety and operational standards for non-pressurized, open-bath thermal equipment (per IEC 61010-1:2010 for electrical safety). The bath operates exclusively in heating mode, with no cooling capability, and is optimized for use in ambient-to-100 °C workflows including sample preparation, enzymatic assays, dissolution testing, and controlled solubilization—particularly where thermal homogeneity and mechanical mixing must be decoupled from forced circulation.

Key Features

• Independent PID temperature control per bath zone, delivering ±0.1 °C stability at setpoints across the full 20–100 °C operating range (ambient-dependent lower limit)
• Six motor-driven stirring stations, each equipped with a brushless DC motor rated for continuous duty at up to 3000 rpm; individual speed adjustment via digital interface (300–3000 rpm, 10-rpm increments)
• Stainless steel (AISI 304) bath tank and quick-release stainless steel clamping fixtures for Ø6 mm stirring rods (200 mm length), minimizing corrosion risk and enabling rapid tool exchange between experiments
• Height-adjustable vertical support column with non-slip rubber base and dual-locking mechanism, accommodating vessels from 50 mL test tubes to 1000 mL beakers without lateral instability
• Digital LED display showing real-time bath temperature and selected stirring speed for each station; memory function retains last-used parameters after power cycle
• Over-temperature cut-off protection (105 °C mechanical override) and grounded metal housing compliant with Class I electrical safety requirements

Sample Compatibility & Compliance

The EWS-16 accommodates standard laboratory glassware—including borosilicate beakers, Erlenmeyer flasks, and jacketed reaction vessels—within its 6 × 1000 mL capacity configuration. It supports aqueous solutions, buffer systems, glycerol-water mixtures, and silicone oil baths (up to 100 °C), though oil use requires manual verification of flash point compatibility. The device meets CE marking requirements for laboratory equipment under Directive 2014/30/EU (EMC) and 2014/35/EU (LVD). While not certified for GMP or GLP environments out-of-the-box, its temperature logging capability (via optional RS-232 output) enables integration into validated workflows adhering to FDA 21 CFR Part 11 when paired with compliant data acquisition software. It is routinely deployed in applications referenced in USP (dissolution testing), ISO 8573-1 (compressed air purity—sample conditioning), and ASTM D129 (sulfur content analysis—reagent preheating).

Software & Data Management

The EWS-16 operates as a standalone instrument with embedded firmware; no proprietary PC software is required for basic operation. Optional RS-232 serial output permits connection to external data loggers or LIMS platforms for time-stamped temperature and speed recording. When integrated into regulated environments, users may implement audit-trail-capable third-party software (e.g., LabArchives ELN or DeltaV DCS modules) to satisfy ALCOA+ data integrity principles. Firmware updates are performed manually via USB interface (not included), with version history and calibration logs stored internally for traceability. Calibration certificates (NIST-traceable reference thermometer verification) are available upon request for IQ/OQ documentation packages.

Applications

• Pharmaceutical R&D: Standard solution preparation for HPLC and UV-Vis analysis; dissolution medium conditioning per USP apparatus II protocols
• Biotechnology: Enzyme kinetic studies requiring constant temperature and homogeneous substrate distribution; plasmid miniprep lysis step incubation with gentle agitation
• Food & Beverage QA: Fat extraction solvent preheating (e.g., petroleum ether at 60 °C); viscosity standardization of emulsions prior to rheological testing
• Chemical Synthesis: Low-temperature esterification reactions (<80 °C) where thermal gradients must be minimized and reagent dispersion ensured
• Environmental Testing: BOD5 incubation of diluted wastewater samples with concurrent aeration-free mixing to prevent oxygen transfer artifacts

FAQ

Does the EWS-16 support programmable temperature ramps or multi-step profiles?
No. It provides single-setpoint temperature control only; ramping functionality is not implemented in the current firmware.
Can the stirring motors operate independently while the bath remains at a fixed temperature?
Yes. Each of the six stirrers can be started, stopped, or speed-adjusted individually without affecting bath temperature regulation.
Is the unit compatible with external temperature probes for sample-specific feedback control?
No. Temperature sensing is bath-reservoir-based only; no provision exists for immersion probe input or cascade control loops.
What maintenance is required for long-term reliability?
Annual inspection of motor brushes (if applicable), verification of heater element resistance, and replacement of silicone sealing gaskets every 24 months under continuous use.
Does DRETOP provide factory calibration documentation with shipment?
A basic calibration report (bath temperature vs. certified reference thermometer at 37 °C, 60 °C, and 95 °C) is included; full ISO/IEC 17025-accredited calibration is available as a paid option.