OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer

Overview

The OHAUS GUARDIAN™5000 Advanced Heating Magnetic Stirrer is engineered for precision, safety, and reproducibility in demanding laboratory environments—including R&D laboratories, academic teaching facilities, and industrial QC/QA settings. It operates on the principle of magnetic coupling: a rotating permanent magnet beneath the heating plate induces synchronous rotation of a PTFE- or glass-coated stir bar immersed in the sample vessel. Heat transfer occurs via conduction through a high-thermal-conductivity ceramic plate, enabling uniform temperature distribution across the surface. Unlike resistive coil-based systems, the GUARDIAN™5000’s solid-ceramic heating element delivers stable thermal output up to 550 °C with minimal thermal lag and no hot-spot formation—critical for temperature-sensitive protocols such as enzyme activation, buffer equilibration, and sterile media preparation. Its robust all-metal chassis, integrated thermal cutoffs, and IP32-rated enclosure meet baseline mechanical and environmental resilience requirements for continuous operation under routine lab conditions.

Key Features

• Triple-mode temperature control: rapid ramp, precise setpoint hold, and overshoot-suppressed heating—optimized for both kinetic studies and endpoint stabilization
• Ceramic square heating plate (18 cm × 18 cm) offering superior thermal uniformity, chemical resistance, and long-term dimensional stability versus aluminum or coated variants
• High-energy samarium-cobalt (SmCo) drive magnet assembly ensuring consistent torque delivery at low speeds (50 rpm) and stable operation up to 1,800 rpm—even with viscous or dense solutions
• Ergonomic front-panel tilt design (15° angle) improves line-of-sight visibility during benchtop use without requiring repositioning of vessels or personal protective equipment
• RS232 serial interface enables integration with LIMS, SCADA, or custom data acquisition software for audit-trail-compliant logging (e.g., GLP/GMP-aligned timestamped temperature and speed records)
• Acoustic alert system with configurable tone and duration; visual status indicators (green = operational, amber = high-temp warning) conform to IEC 60417-5009 and ISO 7010-W001 conventions
• Optional splash guard with quick-lock mounting—designed for compatibility with standard round-bottom flasks (50–2,000 mL) and beakers (100–5,000 mL)

Sample Compatibility & Compliance

The GUARDIAN™5000 accommodates vessels ranging from 10 mL test tubes to 20 L carboys, provided appropriate stir bar geometry (e.g., cross-shaped or oval bars for high-viscosity media) and thermal mass are considered. It supports common laboratory glassware (borosilicate 3.3), stainless steel containers, and chemically resistant polymer vessels rated for continuous exposure up to 550 °C. The device complies with EN 61010-1:2010 (Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use) and carries CE and TÜV marks verifying conformity with EU Low Voltage and EMC Directives. Its IP32 rating certifies protection against vertically falling droplets and solid objects ≥2.5 mm—suitable for non-hazardous wet-bench applications but not recommended for fume hood interiors without supplemental containment.

Software & Data Management

While the GUARDIAN™5000 operates as a standalone instrument with intuitive rotary-knob control, its RS232 port supports bidirectional communication using ASCII-based command protocols. Users may log real-time parameters—including actual temperature (±1 °C accuracy), setpoint, rotational speed (±2 rpm resolution), elapsed time, and alarm status—to external PCs or PLCs. When deployed in regulated environments, this capability facilitates compliance with FDA 21 CFR Part 11 requirements when paired with validated third-party software that enforces electronic signature, audit trail, and user access controls. No proprietary drivers or cloud dependencies are required; raw data export is compatible with CSV, Excel, and LabVIEW-compatible formats.

Applications

• pH adjustment and buffering of aqueous reagents under controlled thermal conditions
• Preparation of agarose and polyacrylamide gels with homogeneous polymerization kinetics
• Thermal denaturation studies of proteins and nucleic acids (e.g., melting curve analysis prior to qPCR)
• Sterilization of liquid media via sustained boiling (100 °C, 15–20 min) with active stirring to prevent localized scorching
• Dissolution testing of pharmaceutical excipients per USP <711> guidelines
• Exothermic reaction quenching by rapid cooling followed by controlled reheating/stirring sequences
• Preparation of calibration standards for ICP-OES and HPLC where trace metal contamination must be minimized (ceramic surface eliminates leaching risks associated with metal plates)

FAQ

What is the maximum recommended viscosity for stable stirring at 1,800 rpm?
For optimal performance and motor longevity, OHAUS recommends limiting use to Newtonian fluids with dynamic viscosity ≤5,000 mPa·s at operating temperature. Higher viscosities require reduced speed and larger-diameter stir bars.
Can the GUARDIAN™5000 be used inside a nitrogen-purged glovebox?
Yes—provided the unit is externally powered via feedthrough and ambient humidity remains below 80% RH. The IP32 rating does not preclude inert-atmosphere use, though optional splash guard installation is advised to minimize particulate ingress.
Is firmware upgrade supported via RS232?
No. Firmware is factory-programmed and immutable in field operation. All functional updates are implemented through hardware revision cycles (e.g., model e-G52ST07C supersedes earlier e-G52ST07B units).
Does the timer function retain settings after power interruption?
No. The timer is volatile and resets upon loss of mains power. For mission-critical timed protocols, integration with an uninterruptible power supply (UPS) or external programmable relay is recommended.
Are replacement ceramic plates available as spare parts?
Yes. OHAUS supplies certified OEM ceramic plates (P/N: G52-CER-18SQ) with full traceability and thermal calibration documentation compliant with ISO/IEC 17025.