Hanuo HJ-4 Digital Magnetic Stirrer

Overview

The Hanuo HJ-4 Digital Magnetic Stirrer is a multi-position laboratory stirring system engineered for simultaneous, independent agitation of up to four samples—each with a maximum volume of 1000 mL. Unlike single-station stirrers, this four-head configuration leverages proven magnetic coupling principles: rotating permanent magnets beneath each station generate a controlled rotating magnetic field that drives PTFE- or ceramic-coated stir bars immersed in vessels. The device operates without mechanical shafts or seals, eliminating contamination risk and enabling sterile or sealed-vessel applications. Designed for routine sample preparation, reagent homogenization, dissolution testing, and buffer equilibration in QC labs, academic research facilities, and pharmaceutical development environments, the HJ-4 delivers consistent torque delivery across its full speed range (0–2400 rpm) and maintains stable rotational output under variable load conditions—critical for reproducible mixing kinetics in comparative studies.

Key Features

• Four independent stirring stations, each rated for 1000 mL capacity—ideal for parallel sample processing and experimental replication
• Digital LED speed display with precise rotary encoder control for repeatable setpoint adjustment and real-time rpm verification
• Integrated heating elements (4 × 200 W total) providing uniform thermal input per station; suitable for temperature-assisted dissolution or viscosity reduction during mixing
• Robust ceramic-coated aluminum plate surface offering high thermal conductivity, chemical resistance, and long-term dimensional stability
• Overheat protection circuitry and motor thermal cutoff safeguards prevent coil damage during extended operation or dry-run scenarios
• Low-noise brushless DC motor design ensures continuous operation at high speeds without significant vibration transmission to adjacent instrumentation

Sample Compatibility & Compliance

The HJ-4 accommodates standard laboratory glassware—including beakers (50–1000 mL), Erlenmeyer flasks, and cylindrical reaction vessels—provided stir bar geometry and size are matched to vessel diameter and liquid depth. It supports common stir bar types (e.g., oval, cross, and micro shapes) with lengths from 20 mm to 50 mm. While the unit itself does not include integrated temperature sensing or PID regulation, its heating function complies with general-purpose lab equipment safety standards (IEC 61010-1). For regulated environments, users may integrate external PT100 probes and data loggers to document thermal profiles per ASTM E2912 or USP auxiliary equipment validation requirements. No built-in GLP/GMP audit trail or 21 CFR Part 11-compliant electronic records are provided; however, analog speed and power settings remain fully traceable via physical control interface.

Software & Data Management

The HJ-4 operates as a standalone hardware platform with no embedded firmware, network interface, or proprietary software suite. All operational parameters—including speed setpoints and on/off status—are managed manually via front-panel controls. This architecture eliminates cybersecurity vulnerabilities associated with connected lab devices and simplifies qualification protocols (IQ/OQ/PQ) in GxP-regulated workflows. Users requiring documentation can pair the unit with third-party USB data acquisition modules (e.g., National Instruments USB-TC01 or Omega OM-DAQ-USB-2401) to record real-time rpm and surface temperature (via external thermocouple) into CSV or LIMS-compatible formats. Calibration certificates for speed accuracy (±2% of setpoint, traceable to NIST-standard tachometers) are available upon request for metrological traceability.

Applications

• Routine buffer and media preparation in molecular biology and cell culture labs
• Parallel dissolution testing of solid dosage forms under pharmacopeial conditions (USP , Ph. Eur. 2.9.3)
• Homogenization of nanoparticle suspensions prior to DLS or TEM analysis
• pH adjustment and titrant mixing in environmental water quality testing (EPA Method 9040C)
• Catalyst slurry conditioning in heterogeneous reaction screening workflows
• Extraction protocol standardization across multiple solvent systems in natural product isolation

FAQ

Does the HJ-4 support temperature feedback control or digital temperature display?
No—the HJ-4 includes heating functionality but lacks integrated temperature sensors, PID controllers, or numeric temperature readout. For temperature-critical applications, consider the HJ-4A variant.
Can the stirring speed be synchronized across all four stations?
Yes—speed is adjusted centrally via a single control knob; all four motors operate at the identical rpm value simultaneously.
What is the recommended stir bar size for optimal performance at 1000 mL volume?
A 40 mm × 8 mm oval PTFE-coated stir bar is empirically validated for efficient vortex formation and bottom-layer mixing in 1000 mL beakers at speeds ≥800 rpm.
Is the unit compatible with corrosive solvents such as concentrated acids or halogenated organics?
The ceramic-coated top plate resists mild corrosion; however, prolonged exposure to strong oxidizers (e.g., aqua regia) or hot chlorinated solvents requires supplemental containment (e.g., secondary trays) and regular surface inspection.
Does Hanuo provide factory calibration documentation or service support outside China?
Calibration reports (speed accuracy, heater output) are issued per batch; international technical support is coordinated through authorized regional distributors with local service agreements.