IKA RW 28 digital Overhead Stirrer
| Brand | IKA |
|---|---|
| Origin | Germany |
| Model | RW 28 digital |
| Stirrer Type | Electric Overhead Stirrer |
| Max. Mixing Volume (H₂O) | 80 L |
| Speed Range | 60–400 rpm (Range I, 50 Hz) / 240–1400 rpm (Range II, 50 Hz) |
| Temperature Operating Range | 5–40 °C |
| Motor Output Power | 90 W |
| Max. Torque | 900 N·cm (Range I) / 300 N·cm (Range II) |
| Shaft Clamp Capacity | 1–10 mm |
| IP Rating | IP40 |
| Noise Level | 62.5 dB(A) |
| Dimensions (W×H×D) | 123 × 364 × 252 mm |
| Weight | 7.5 kg |
Overview
The IKA RW 28 digital is a high-performance overhead stirrer engineered for precision mixing and dispersion in laboratory and pilot-scale environments. Based on robust mechanical torque transmission and constant-power drive architecture, it delivers consistent rotational energy across variable load conditions—particularly critical when processing viscous or non-Newtonian fluids. Unlike magnetic stirrers, the RW 28 employs a direct-drive motor coupled to an interchangeable stirring shaft via a precision-machined chuck, enabling reliable torque transfer up to 900 N·cm at low speeds (60 rpm), making it suitable for applications ranging from polymer solution homogenization to suspension stabilization in pharmaceutical formulations. Its dual-speed-range design (Range I: 60–400 rpm; Range II: 240–1400 rpm, both at 50 Hz) allows users to optimize shear rate profiles without mechanical gear shifting—ensuring reproducible process scalability from benchtop to pre-production batches.
Key Features
- Digitally controlled speed regulation with ±1 rpm setting resolution and LED display for real-time feedback
- Two selectable speed ranges optimized for high-torque (low-speed) and high-shear (high-speed) operations
- Integrated thermal protection circuitry that automatically limits motor temperature rise during extended operation
- Overload detection with error code display for rapid troubleshooting and system diagnostics
- Ergonomically designed cast aluminum housing with thermoplastic coating for chemical resistance and mechanical durability
- Quiet operation at ≤62.5 dB(A) under no-load conditions—suitable for shared lab environments requiring acoustic compliance
- Hollow shaft design (10.5 mm internal diameter) permitting insertion of temperature probes or pH electrodes during active mixing
- IP40-rated enclosure providing protection against solid objects ≥1 mm and limited ingress of vertically falling water droplets
Sample Compatibility & Compliance
The RW 28 digital accommodates a broad spectrum of sample viscosities—from aqueous solutions (<1 mPa·s) up to highly structured gels and pastes (up to 50,000 mPa·s). Its 1–10 mm chuck range supports standard ISO-compliant stirring elements including anchor, paddle, propeller, and helical impellers. While not certified for hazardous area use (non-explosion-proof), the unit meets DIN EN 60529 (IP40), EN 61000-6-3 (EMC emission limits), and EN 61000-6-2 (immunity standards). It operates within ambient conditions compliant with GLP environmental monitoring guidelines (5–40 °C, ≤80% RH), supporting routine QC testing under regulated frameworks such as ISO/IEC 17025 and USP .
Software & Data Management
This model does not feature USB, RS232, or analog output interfaces; therefore, it functions as a standalone instrument without direct computer integration or data logging capability. All operational parameters—including current speed, error status, and overload events—are displayed locally via the integrated LED screen. For laboratories requiring audit-trail functionality or electronic record retention, external validation-compatible data loggers may be employed in conjunction with calibrated tachometers or torque sensors—fully compatible with 21 CFR Part 11-compliant documentation systems when configured per site-specific SOPs.
Applications
- Homogenization of high-viscosity polymer melts and resin blends in materials science labs
- Preparation of stable colloidal suspensions and emulsions in formulation development
- Mixing of cell culture media and buffer solutions in bioprocessing R&D
- Dispersion of nanoparticles and pigments in coating and ink development
- Batch-wise dissolution testing of poorly soluble APIs under pharmacopeial conditions (e.g., USP Apparatus 2 equivalents)
- Pilot-scale reaction mixing where scalable shear input must be maintained between development and manufacturing stages
FAQ
Is the RW 28 digital suitable for continuous operation?
Yes—it is rated for 100% duty cycle under specified ambient and load conditions, provided thermal protection thresholds are not exceeded.
Can it be used with jacketed reactors?
Yes, the hollow shaft design permits concurrent insertion of cooling/heating probes, and its mounting flexibility supports standard lab reactor clamps and support arms.
Does it meet FDA or GMP requirements?
While the device itself carries no FDA clearance, its construction, repeatability, and environmental operating envelope align with equipment qualification protocols (IQ/OQ/PQ) required under GMP Annex 15 and EU GMP Chapter 4.
What safety certifications does it hold?
It complies with IEC 61010-1 (Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use) and bears CE marking for conformity with EU directives.
Is calibration traceable to national standards?
Speed and torque calibration can be performed using NIST-traceable tachometers and torque analyzers; IKA provides factory calibration certificates upon request for metrological verification.
