OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer

Overview

The OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer is an engineered solution for precise thermal and mechanical sample manipulation in analytical, pharmaceutical, academic, and industrial laboratories. It operates on the principle of magnetic coupling—using a high-performance samarium-cobalt (SmCo) magnet rotor driven by a synchronous motor beneath a thermally stable ceramic heating surface—to induce rotational motion in magnetic stir bars immersed in liquid samples. Unlike conventional hotplate stirrers with limited thermal uniformity or insufficient torque at elevated temperatures, the GUARDIAN™5000 integrates closed-loop PID temperature regulation with real-time speed feedback, enabling reproducible control across demanding protocols such as buffer preparation, sterilization, pH equilibration, and heat-sensitive biomolecular dissolution. Its design adheres to fundamental laboratory safety and operational integrity requirements—including thermal runaway prevention, over-temperature cutoff, and audible/visual fault signaling—making it suitable for unattended operation under GLP-compliant workflows.

Key Features

• Robust all-metal chassis with IP32 ingress protection, supporting long-term use in humid or splash-prone environments.
• Ceramic square heating plate (26 cm × 26 cm) offering superior thermal homogeneity, chemical resistance, and rapid heat-up response up to 500°C.
• Triple-mode temperature control: Fast Ramp, Precision Hold, and Auto-Safe Limit—each configurable via intuitive rotary interface and backlit LCD.
• Independent 3-point calibration capability for both internal heating plate sensor and optional external Pt100/Pt1000 probes, ensuring traceable accuracy per ISO/IEC 17025 metrological practices.
• RS232 serial interface compliant with standard SCPI command sets, enabling integration into LIMS or automated lab systems for audit-trail-enabled data capture (e.g., time-stamped temperature/speed logs).
• Ergonomic front-panel tilt angle (15°) and high-contrast white-on-black LCD facilitate visual monitoring from benchtop height without parallax error.
• Programmable timer (1 min – 99 h 59 min) with auto-shutdown and alarm notification upon completion or deviation beyond user-defined thresholds.

Sample Compatibility & Compliance

The GUARDIAN™5000 accommodates vessels ranging from small vials (≥10 mL) to large-capacity beakers and flasks (up to 22 L), provided magnetic coupling remains effective—i.e., stir bar size and geometry are matched to viscosity, depth, and container shape. It supports common laboratory glassware (borosilicate, Pyrex) and select chemically resistant polymers (e.g., PTFE-lined caps, polypropylene bottles). The device meets CE marking requirements under the EU Low Voltage Directive (2014/35/EU) and Electromagnetic Compatibility Directive (2014/30/EU), and carries TÜV Rheinland certification confirming conformity with EN 61010-1:2010 for electrical safety in laboratory equipment. While not intrinsically rated for explosive atmospheres, its surface temperature classification complies with EN 60079-0 for non-hazardous zone deployment. For regulated environments, the RS232 interface supports 21 CFR Part 11–compliant data export when paired with validated third-party software.

Software & Data Management

No proprietary software is bundled; however, the built-in RS232 port enables bidirectional communication using industry-standard terminal emulators (e.g., PuTTY, Tera Term) or custom Python/Node.js scripts. Supported commands include real-time query of current temperature, setpoint, RPM, timer status, and fault codes. Logged data can be timestamped and exported in CSV format for downstream analysis in Excel, MATLAB, or statistical process control (SPC) platforms. Audit trail functionality—including operator ID tagging, parameter change history, and session start/stop timestamps—is achievable through external middleware compliant with ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available).

Applications

• Preparation of aqueous and organic solutions requiring simultaneous heating and homogeneous mixing (e.g., agarose gels, culture media, extraction buffers).
• Thermal stabilization studies involving enzyme kinetics, protein denaturation, or polymer solubilization where ramp rate and plateau precision impact reaction fidelity.
• Quality control testing in pharmaceutical manufacturing—such as dissolution profile verification per USP —where batch-to-batch consistency depends on controlled thermal input and agitation intensity.
• Environmental sample digestion protocols (e.g., EPA Method 3050B) necessitating extended heating cycles with minimal operator intervention.
• Materials science workflows including nanoparticle dispersion, precursor mixing for sol-gel synthesis, and solvent evaporation under inert atmosphere (when used with compatible enclosures).

FAQ

What temperature probe options are supported?
The GUARDIAN™5000 accepts optional Pt100 or Pt1000 resistance temperature detectors (RTDs) for direct sample measurement. These probes connect via a standardized mini-DIN interface and are calibrated independently from the heating plate sensor.
Is the unit compatible with GMP documentation requirements?
Yes—when integrated with validated data acquisition software and configured with electronic signatures, the RS232 output satisfies key elements of FDA 21 CFR Part 11 for electronic records and signatures in regulated labs.
Can the stirrer operate continuously for 24 hours?
Yes—the system is rated for continuous duty within its specified ambient conditions (5–40°C, ≤80% RH). Thermal management includes overheat shutdown and automatic fan-assisted cooling during prolonged high-temperature operation.
How is speed stability maintained across the full range?
A brushless DC motor with closed-loop tachometer feedback ensures ±2% speed consistency regardless of load inertia or viscosity changes, verified per ASTM E2917-20 Annex A1 for rotational speed accuracy.
Does the ceramic plate support autoclave-compatible cleaning agents?
Yes—the fully glazed alumina-based ceramic surface resists corrosion from common disinfectants (e.g., 70% ethanol, 1% sodium hypochlorite) and withstands repeated wipe-downs without degradation of emissivity or thermal response time.