IKA RW 28 digital Overhead Stirrer

Overview

The IKA RW 28 digital is a high-performance overhead stirrer engineered for precision mixing and dispersion tasks in research laboratories, quality control environments, and pilot-scale production settings. Designed according to the principles of robust mechanical torque transmission and thermal stability, it operates on a dual-range stepless speed control system—enabling consistent shear delivery across low- to high-viscosity media. Its core architecture features a cast aluminum housing with thermoplastic polymer coating, ensuring structural rigidity and chemical resistance while minimizing vibration-induced drift. The device employs a brush-type DC motor with integrated thermal cut-off protection, automatically limiting operation if internal temperature exceeds safe thresholds—critical for unattended or extended-duration runs. Unlike entry-level stirrers reliant on gear reduction alone, the RW 28 digital utilizes constant-torque drive technology that maintains nominal output across its full operational range, particularly advantageous when processing non-Newtonian fluids such as polymer solutions, suspensions, or pastes.

Key Features

• Stepless mechanical speed control with two selectable ranges: 60–400 rpm (Range I) and 240–1400 rpm (Range II) at 50 Hz; extended to 72–480 rpm and 288–1680 rpm respectively at 60 Hz
• High-resolution LED display showing real-time rotational speed with ±1 rpm setting accuracy and ±10 rpm measurement tolerance
• Dual-torque capability: rated torque of 900 N·cm at 100 rpm; peak overload torque up to 1144 N·cm at 60 rpm for transient high-load conditions
• Hollow stainless steel stirring shaft (ID 10.5 mm) compatible with auxiliary probes (e.g., temperature sensors or pH electrodes) inserted during stationary operation
• Ergonomic height-adjustable support arm (145 mm length, Ø16 mm diameter) with quick-lock clamping mechanism for secure mounting on standard lab frames
• IP 40 ingress protection rating ensures resistance against solid objects >1 mm and limited dust exposure—suitable for general laboratory use under controlled environmental conditions (5–40 °C, ≤80 % RH)
• Low-noise operation at 62.5 dB(A) without dispersing head attached, supporting compliance with occupational noise exposure guidelines (OSHA 29 CFR 1910.95)

Sample Compatibility & Compliance

The RW 28 digital accommodates vessels from beakers (≥500 mL) to jacketed reactors (up to 80 L water-equivalent volume), supporting both batch and semi-continuous processes. Its wide viscosity handling range (up to 50,000 mPa·s) makes it suitable for formulations including adhesives, cosmetic emulsions, battery slurries, and pharmaceutical suspensions. The unit conforms to EN 61000-6-3 (EMC emission limits) and EN 61000-6-2 (immunity requirements), and meets essential safety criteria per EN 61010-1:2010 for electrical equipment used in laboratory environments. While not intrinsically rated for explosive atmospheres, optional accessories—including explosion-proof motor housings and ATEX-compliant controllers—are available through IKA’s certified engineering partners for regulated industrial applications.

Software & Data Management

As a standalone analog-mechanical instrument, the RW 28 digital does not incorporate embedded firmware or digital connectivity (e.g., USB, RS232, or Ethernet). However, its stable analog control loop ensures immunity to electromagnetic interference and long-term calibration stability—advantageous in GLP/GMP-regulated workflows where software validation burdens are minimized. For traceability, users may integrate external data loggers via analog voltage output (0–10 V) corresponding to actual shaft speed. All operational parameters—including torque alerts, thermal lockouts, and error codes (e.g., E1 = overload, E2 = sensor fault)—are displayed directly on the front-panel LED interface. Documentation packages include full CE declaration of conformity, RoHS compliance statement, and ISO 9001-certified manufacturing records.

Applications

• Homogenization of high-viscosity polymer melts prior to rheological characterization (ASTM D3835)
• Preparation of uniform ceramic or electrode slurries for battery R&D (IEC 62660-1)
• Emulsion stabilization trials in cosmetic formulation development (ISO 16128-2)
• Buffer and media preparation in biopharmaceutical upstream processing (USP )
• Mixing of catalyst suspensions in fine chemical synthesis under inert atmosphere (Schlenk line compatibility)
• Scale-down validation of mixing parameters from pilot to production scale (ICH Q5C)

FAQ

Is the RW 28 digital compatible with glass reactor jackets?

Yes—the support arm and clamping system accommodate standard Ø16 mm vertical rods, enabling secure mounting above jacketed vessels up to 100 mm wall thickness. Ensure proper alignment to avoid shaft runout.
Can the hollow shaft accept PT100 temperature probes?

Yes—provided the probe outer diameter is ≤10 mm and its sheath material is chemically inert to the process medium. Insertion must occur only when the shaft is stationary.
Does this model meet FDA 21 CFR Part 11 requirements?

No—this is an analog-controlled instrument without electronic audit trail, user authentication, or electronic signature capabilities. For Part 11 compliance, consider IKA’s Labworldsoft-integrated systems (e.g., RW 20 digital with RS232 + software logging).
What maintenance intervals are recommended?

IKA recommends annual inspection of carbon brushes and bearing preload; lubrication is factory-sealed and non-serviceable. Visual inspection of clamping jaws and shaft threads should occur before each use.
Is the unit suitable for continuous operation over 8 hours?

Yes—rated for 100 % duty cycle under ambient conditions ≤35 °C and relative humidity ≤60 %. At higher ambient loads, derating of maximum torque by 15 % is advised per IKA Technical Bulletin TB-RW28-03.