Hanuo S21-1 Dual-Direction Magnetic Stirrer
| Brand | Hanuo |
|---|---|
| Origin | Shanghai, China |
| Model | S21-1 |
| Stirring Capacity | 3 L |
| Speed Range | 0–2600 rpm |
| Temperature Control Range | Ambient to 100 °C |
| Timer Range | 0–120 min |
| Functionality | Dual-direction rotation, stepless speed control, timer |
| Compliance | CE-marked design for laboratory use under IEC 61010-1 safety standard |
Overview
The Hanuo S21-1 Dual-Direction Magnetic Stirrer is an electromechanical laboratory instrument engineered for precise, reproducible mixing of low-to-medium viscosity liquids and homogeneous solid–liquid suspensions. It operates on the principle of rotating magnetic coupling: a high-energy permanent magnet array in the base unit generates a time-varying magnetic field that induces synchronous rotational motion in a PTFE- or glass-coated magnetic stir bar placed within the sample vessel. Unlike unidirectional stirrers, the S21-1 incorporates programmable bidirectional rotation—alternating clockwise and counterclockwise cycles—to minimize vortex formation, reduce bubble entrapment, and improve homogenization efficiency in sensitive or shear-sensitive applications. Its robust aluminum alloy housing ensures thermal stability and mechanical durability during extended operation, while the sealed control electronics provide resistance to incidental spills and ambient moisture.
Key Features
- Dual-direction rotation mode with user-selectable cycle duration (1–60 s per direction), enabling uniform dispersion without stratification or localized shear hotspots
- Stepless electronic speed control (0–2600 rpm) with real-time feedback circuitry ensuring ±2% speed stability across load variations
- Integrated digital timer (0–120 min) with auto-shutdown function to support unattended protocols and ensure experimental repeatability
- High-strength neodymium–iron–boron (NdFeB) magnetic drive system delivering consistent torque up to 3 L volume with standard 30 mm stir bars
- Low-profile platform design compatible with standard borosilicate glass beakers (50–2000 mL) and flat-bottom flasks; optimized for use under fume hoods or inside environmental chambers
- CE-compliant construction meeting IEC 61010-1:2010 requirements for electrical safety in laboratory equipment
Sample Compatibility & Compliance
The S21-1 is validated for use with aqueous solutions, organic solvents (e.g., ethanol, acetone, chloroform), buffer systems, and dilute colloidal suspensions. It supports stirring of samples in containers up to 3 L volume when using appropriately sized stir bars (recommended: 40 mm × 8 mm for >2 L volumes). The device does not incorporate active heating; therefore, it complies with non-heating equipment classifications under ISO/IEC 17025 calibration traceability frameworks. For GLP- or GMP-regulated environments, the timer function provides auditable start/stop timestamps, and the absence of analog dials eliminates parallax reading errors. While not FDA 21 CFR Part 11 compliant out-of-the-box (as it lacks electronic signature capability), its deterministic operational logic supports integration into validated workflows when paired with external data loggers.
Software & Data Management
The S21-1 is a standalone hardware device with no embedded firmware, network interface, or proprietary software dependency. All operational parameters—including speed setpoint, direction sequence, and timer value—are configured via tactile membrane keypad with LED display. This architecture ensures long-term reliability, eliminates cybersecurity exposure, and avoids obsolescence risks associated with driver-dependent USB or Bluetooth connectivity. For laboratories requiring documentation of stirring conditions, optional RS-232 or analog 0–10 V output modules (sold separately) enable connection to third-party data acquisition systems (e.g., LabVIEW, MATLAB, or SCADA platforms) for timestamped logging of speed and runtime.
Applications
- Preparation of standard solutions and calibration standards in analytical chemistry labs (e.g., HPLC mobile phase blending, titrant homogenization)
- Mixing of cell culture media and reagent buffers in life science research, where gas dissolution control and minimal foaming are critical
- Accelerated dissolution testing of pharmaceutical powders per USP , particularly when combined with temperature-controlled water baths
- Homogenization of polymer precursor mixtures prior to casting or extrusion in materials science workflows
- Supporting ASTM D445 (kinematic viscosity) sample conditioning by ensuring thermal equilibration and particle suspension prior to capillary viscometer loading
- Teaching laboratory use in undergraduate chemistry and chemical engineering courses for demonstrating mass transfer, reaction kinetics, and fluid dynamics principles
FAQ
Does the S21-1 include a heating function?
No. The S21-1 is a non-heating magnetic stirrer. Models S21-2 through S21-5 integrate heating elements and temperature control; refer to their respective technical specifications.
What stir bar size is recommended for maximum 3 L capacity?
A 40 mm × 8 mm cylindrical PTFE-coated stir bar is optimal for vessels ≥2 L. Smaller bars (e.g., 30 mm) may stall at high speeds or low viscosities above 1.5 L.
Is the timer programmable in seconds or minutes?
The timer resolution is 1 minute; total duration is adjustable from 1 to 120 minutes in 1-minute increments.
Can the S21-1 operate continuously beyond 120 minutes?
Yes—by disabling the timer, the unit runs indefinitely at the selected speed until manually powered off.
What safety certifications does this unit hold?
It carries CE marking per Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and conforms to IEC 61010-1:2010 for laboratory electrical equipment safety.
