DRETOP JOH-5-260 Integrated Hotplate Magnetic Stirrer

Overview

The DRETOP JOH-5-260 Integrated Hotplate Magnetic Stirrer is an engineered solution for laboratories requiring simultaneous precise thermal control and robust mechanical mixing in a single compact platform. Unlike conventional magnetic stirrers or standalone heating mantles, this device integrates a high-efficiency ring-type immersion heater with a powerful electromagnetic drive system—enabling uniform heat distribution across the bath medium (water, silicone oil, or mineral oil) while maintaining stable, contactless rotation of PTFE-coated magnetic stir bars. Its operating principle relies on eddy current induction within the ferromagnetic core of the stir bar, coupled with conduction-based thermal transfer from the heated aluminum alloy bath plate and surrounding insulated chamber. Designed for sustained operation at elevated temperatures up to 400 °C, it supports demanding applications in synthetic chemistry, polymerization kinetics, catalyst screening, and stability testing where both thermal homogeneity and shear-controlled agitation are critical parameters.

Key Features

• Microprocessor-controlled PID temperature regulation with dual LED display showing setpoint and real-time bath temperature—ensuring repeatability within ±0.1 °C accuracy and long-term stability of ±0.5 °C.
• 0–2400 rpm continuous speed adjustment via rotary encoder or digital keypad; no gear-driven mechanisms—eliminating mechanical wear and enabling fine-tuned shear rate control.
• Integrated 800 W ring heater embedded beneath a corrosion-resistant stainless steel bath pan (Φ260 × 150 mm), delivering rapid thermal response and minimal radial temperature gradients (<1.5 °C across 8 L volume).
• Multi-layer thermal insulation with water-tight chamber design and integrated drain valve—facilitating safe, efficient media replacement without disassembly.
• PTFE-encapsulated magnetic stir bars rated for continuous use up to 400 °C, offering chemical inertness against strong acids, bases, and organic solvents.
• Power-fail recovery mode retaining last-used temperature and speed settings; programmable over-temperature alarm with audible/visual alert to meet GLP-compliant operational safeguards.

Sample Compatibility & Compliance

The JOH-5-260 accommodates vessels ranging from 50 mL glass vials to 5 L round-bottom flasks, provided they fit within the bath footprint and maintain adequate clearance for stir bar motion. It is validated for use with aqueous solutions, glycerol, ethylene glycol, silicone oils (e.g., Dow Corning 200 Fluid), and mineral oils—subject to flash point and viscosity constraints. The unit complies with IEC 61010-1:2010 for laboratory electrical equipment safety, including protection against overheating, electric shock, and mechanical hazards. While not inherently 21 CFR Part 11 compliant, its parameter logging capability (via optional RS232/USB interface) supports audit-ready data capture when integrated into validated workflows under ISO/IEC 17025 or GMP environments.

Software & Data Management

The JOH-5-260 operates as a standalone instrument with embedded firmware; no proprietary software is required for basic operation. Optional communication modules enable serial output of temperature, speed, and timer status at user-defined intervals (1–60 s), compatible with LabVIEW, MATLAB, or custom SCADA systems. All logged data include timestamps and device ID, supporting traceability requirements for method validation. Firmware updates are performed via USB flash drive, ensuring field-upgradability without hardware modification. Internal memory retains up to 99 programmable protocols—including ramp-soak profiles and multi-step stirring sequences—for repeatable experimental execution.

Applications

• Synthesis of metal–organic frameworks (MOFs) requiring prolonged reflux in high-boiling solvents (e.g., DMF, NMP) under inert atmosphere.
• Enzymatic reaction monitoring in biocatalysis studies, where temperature-sensitive activity assays demand sub-degree thermal control.
• Preparation of nanoparticle dispersions in non-aqueous media, leveraging consistent shear input to prevent agglomeration during nucleation.
• Accelerated stability testing per ICH Q1A(R3), using elevated temperature profiles to model degradation kinetics in pharmaceutical formulations.
• Calibration of viscometers and rheometers using standardized Newtonian fluids across defined thermal gradients.

FAQ

What types of heating media are compatible with the JOH-5-260?
Silicone oil (up to 400 °C), mineral oil (up to 300 °C), and water (up to 100 °C) are supported. Avoid halogenated or low-flash-point solvents due to fire hazard and material compatibility risks.
Can the unit operate under inert gas purge?
Yes—provided the vessel is sealed with appropriate inlet/outlet ports and the bath cover is fitted with a gas-tight gasket; standard configuration includes ventilation slots that must be manually sealed.
Is the stirrer suitable for viscous samples like polymer melts?
It supports viscosities up to ~50,000 mPa·s at 100 °C using appropriately sized stir bars (e.g., 40 mm cross-shaped); torque limitation becomes apparent above 2000 rpm in highly viscous media.
Does the JOH-5-260 support external temperature probe feedback?
No—the built-in Pt100 sensor measures bath temperature only; sample-specific temperature control requires a separate thermocouple-connected controller with relay output.
What maintenance is required for long-term reliability?
Annual inspection of heater insulation resistance (>10 MΩ), cleaning of bath cavity with isopropanol, and verification of stir bar magnetism using a gaussmeter—no lubrication or calibration certificates are factory-supplied.