IKA RW20 Digital Overhead Stirrer System

Overview

The IKA RW20 Digital Overhead Stirrer System is a precision-engineered laboratory stirring solution designed for reproducible, high-torque mixing of low- to medium-viscosity liquids in volumes up to 20 L. Based on robust electromagnetic drive technology and digital speed control, the system delivers consistent rotational motion without mechanical transmission belts or gears—minimizing maintenance and maximizing long-term operational stability. Unlike magnetic stirrers, the RW20 employs an overhead configuration with a vertically aligned motor and interchangeable impellers, enabling effective agitation of heterogeneous mixtures, suspensions, and viscous solutions where bottom-mounted or magnetic agitation would be insufficient or impractical. Its design adheres to core principles of fluid dynamics in laminar-to-transitional flow regimes, ensuring predictable shear input and scalable process transfer from lab to pilot scale.

Key Features

• Digital speed control with real-time RPM display and ±1% speed accuracy across the full 60–2000 rpm range
• High-torque brushless DC motor delivering up to 55 N·cm nominal torque, optimized for continuous operation under load
• Integrated overload protection and thermal cut-off safeguarding both drive unit and sample integrity
• Ergonomic, tool-free height adjustment on the R 1826 stand with fine-positioning scale for precise impeller immersion depth control
• Modular design supporting rapid interchange of stirrer shafts, clamps, and impeller geometries—including axial-flow propellers (R 1342) and anchor or paddle variants (sold separately)
• IP20-rated housing suitable for standard laboratory environments; CE-compliant per EN 61000-6-2 (EMC) and EN 61000-6-4 (emissions)

Sample Compatibility & Compliance

The RW20 Digital system accommodates glass, stainless steel, and polymer reaction vessels ranging from 500 mL to 20 L, provided vessel geometry permits stable mounting via the RH 3 vessel clamp. It is routinely deployed in applications requiring ISO/IEC 17025-aligned method validation, including dissolution testing (USP ), buffer preparation (ICH Q5C), and emulsion formulation under GLP conditions. While the stirrer itself does not regulate temperature, its compatibility with external thermostatic baths (e.g., Julabo or Huber units operating within 5–40 °C) enables isothermal kinetic studies. All included components meet RoHS 2011/65/EU requirements, and material certifications (e.g., stainless steel grade 316L for R 1342 impeller) are available upon request for GMP documentation.

Software & Data Management

The RW20 Digital operates as a standalone instrument without proprietary software dependency. Speed settings and runtime are manually configured via front-panel keypad and retained in non-volatile memory after power cycling. For traceable workflows, users may integrate the unit into validated laboratory information management systems (LIMS) via analog 0–10 V output (optional accessory interface module required). Audit trail functionality—including operator ID, timestamped speed changes, and run duration—is supported when connected to compliant electronic lab notebooks (ELN) platforms adhering to FDA 21 CFR Part 11 requirements. Calibration records follow ISO/IEC 17025 clause 6.5 guidelines and are typically maintained annually using certified tachometers.

Applications

• Preparation of homogeneous aqueous and organic-phase solutions for HPLC mobile phase or cell culture media
• Mixing of polymer dispersions and colloidal suspensions prior to particle size analysis (e.g., laser diffraction per ISO 13320)
• Controlled agitation during pH titration, redox reactions, or enzymatic assays requiring defined shear history
• Scale-down simulation of bioreactor impeller dynamics in microbial fermentation process development
• Homogenization of food-grade emulsions and pharmaceutical suspensions under cGMP-relevant cleanliness protocols

FAQ

Is the RW20 Digital compatible with explosion-proof environments?

No—this model lacks ATEX or IECEx certification and is intended for use in non-hazardous laboratory zones only.
Can the R 1342 propeller be autoclaved?

Yes—the stainless steel R 1342 impeller is autoclavable at 121 °C for 20 minutes; however, the drive unit and clamp components must not be exposed to steam sterilization.
What is the maximum viscosity this system can handle?

Under optimal conditions (20 L volume, R 1342 impeller, 2000 rpm), it reliably processes Newtonian fluids up to ~5,000 mPa·s; performance diminishes above this threshold without torque boost accessories.
Does IKA provide IQ/OQ documentation for GMP installations?

Yes—validated installation qualification (IQ) and operational qualification (OQ) protocols are available through IKA’s Professional Services division upon request and site-specific commissioning.
How often should the drive unit be calibrated?

Annual calibration is recommended per ISO/IEC 17025; interim verification using a traceable optical tachometer is advised before critical experiments.