OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer

Overview

The OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer is an engineered platform for precise, reproducible thermal mixing in research laboratories, academic teaching facilities, and quality-controlled industrial process development environments. It operates on the principle of contactless magnetic coupling—using a high-performance samarium-cobalt (SmCo) permanent magnet rotor driven by a rotating magnetic field beneath a thermally stable ceramic or ceramic-coated aluminum heating plate. This design eliminates mechanical wear associated with overhead stirrers while enabling consistent torque delivery across viscous and low-viscosity media. The unit integrates dual-function control—simultaneous independent regulation of temperature and rotational speed—with a microprocessor-based feedback loop that monitors both heating plate surface temperature (via integrated Pt1000 sensor) and ambient conditions. Its operational envelope spans from ambient +5 °C up to 550 °C, making it suitable for demanding applications such as solvent reflux, polymer dissolution, catalyst activation, and high-temperature buffer equilibration—without compromising thermal uniformity or rotational stability.

Key Features

• Triple-mode temperature control: rapid-heating, precision-hold, and overshoot-suppressed ramping—enabling optimized thermal profiles for sensitive reactions.
• Robust all-metal housing with IP32 ingress protection rating; front-panel tilt angle (15°) enhances ergonomic visibility during benchtop operation.
• Ceramic square heating plate (18 cm × 18 cm) or ceramic-coated aluminum circular plate options—both offering excellent thermal conductivity, chemical resistance, and long-term dimensional stability.
• Digital LCD display with high-contrast white characters and dedicated green status LEDs for active heating/stirring; amber warning indicator activates at >300 °C.
• Acoustic alert system with configurable tone and duration; optional splash guard enables compliant use under ISO 15190:2020 laboratory safety guidelines.
• RS232 serial interface supports bidirectional communication with external data loggers or LIMS platforms—compatible with standard ASCII command protocols for remote parameter setting and real-time telemetry.

Sample Compatibility & Compliance

The GUARDIAN™5000 accommodates vessels ranging from 10 mL test tubes to 20 L glass or stainless-steel reactors, provided magnetic stirring bars are appropriately sized and chemically inert to the sample matrix. It complies with CE marking requirements per Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and carries TÜV certification for electrical safety under EN 61010-1:2010. Temperature calibration is traceable to NIST-traceable standards via three-point verification (at 25 °C, 100 °C, and 300 °C) for both heating plate surface and external Pt1000 probe inputs—supporting GLP documentation workflows. The device meets ISO/IEC 17025:2017 clause 6.4.10 requirements for equipment suitability verification when deployed in accredited testing laboratories.

Software & Data Management

While the GUARDIAN™5000 operates autonomously via front-panel controls, its RS232 port enables integration into regulated environments requiring electronic record integrity. When connected to validated third-party software (e.g., OHAUS LoggerPro™ or custom LabVIEW VIs), it supports time-stamped logging of setpoints, actual temperatures, rotational speeds, and alarm events—including overtemperature, motor stall, and power interruption flags. Audit trail functionality satisfies FDA 21 CFR Part 11 requirements when paired with appropriate system validation documentation and user access controls. All firmware updates are delivered via signed binary packages with SHA-256 checksum verification.

Applications

• Preparation of culture media and enzymatic assay buffers requiring strict pH and thermal consistency.
• Thermal denaturation studies of proteins and nucleic acids under controlled shear conditions.
• Synthesis of metal-organic frameworks (MOFs) and nanoparticle dispersions where localized hot-spot formation must be avoided.
• Accelerated stability testing per ICH Q1A(R3), including elevated-temperature dissolution profiling of pharmaceutical formulations.
• Inorganic salt crystallization trials involving supersaturated solutions maintained at constant sub-boiling temperatures.
• Standardization of reference materials per ISO Guide 35, where homogeneity and thermal history are critical variables.

FAQ

What is the maximum recommended vessel diameter for optimal stirring efficiency?
For full 20 L capacity utilization, a cylindrical vessel with ≤18 cm internal diameter is advised to ensure effective magnetic coupling and radial flow distribution.
Can the unit maintain ±0.5 °C accuracy across its entire temperature range?
Temperature accuracy of ±0.5 °C applies only below 100 °C when using the integrated Pt1000 probe; above this threshold, accuracy degrades to ±1 % of reading per IEC 60751 Class B tolerances.
Is the RS232 interface compatible with modern USB-to-serial adapters?
Yes—standard FTDI- or CH340-based adapters are supported, though galvanic isolation is recommended in electrically noisy production environments.
Does the device support programmable multi-step temperature ramps?
No—ramp profiles must be implemented externally via host software; onboard controls provide only single-setpoint hold or manual adjustment.
What maintenance intervals are specified for the SmCo magnet assembly?
No scheduled maintenance is required; SmCo magnets retain >99.5 % flux density after 10 years at 550 °C continuous exposure, per manufacturer accelerated aging data.