MKN 78HW-1 Precision Magnetic Hotplate Stirrer for Export

Overview

The MKN 78HW-1 Precision Magnetic Hotplate Stirrer is an engineered solution for simultaneous temperature-controlled mixing of liquid samples in research, quality control, and teaching laboratories. It operates on the principle of magnetic coupling: a rotating permanent magnet beneath the ceramic heating plate induces synchronous rotation of a PTFE-coated magnetic stir bar immersed in the sample vessel. This contactless drive mechanism eliminates mechanical shaft seals and ensures leak-free, low-maintenance operation. Integrated PID-based temperature regulation enables stable thermal setpoints across the full ambient-to-100 °C range, with typical stability of ±0.5 °C at 60 °C under standard load conditions. The unit’s brushless DC motor delivers smooth, jitter-free rotation from standstill to 2000 rpm — essential for reproducible dissolution testing, buffer preparation, enzymatic reaction kinetics, and homogeneous reagent blending.

Key Features

• Brushless DC motor architecture ensures ultra-low acoustic noise (<45 dB(A) at 1 m), extended service life, and consistent torque delivery across the entire speed range
• Ceramic-coated aluminum heating plate (135 mm diameter) provides uniform thermal distribution and resistance to chemical splashes and thermal shock
• Digital LED display with dual-channel readout: real-time speed (rpm) and actual plate temperature (°C)
• Independent control knobs for precise, analog-style adjustment of stirring speed and heating setpoint — no menu navigation required
• PTFE-encapsulated stir bars (included) rated for continuous operation up to 100 °C and compatible with acidic, alkaline, and organic media
• Over-temperature cutoff and motor stall protection circuits comply with IEC 61010-1 Edition 3 requirements for laboratory electrical equipment safety

Sample Compatibility & Compliance

The 78HW-1 accommodates standard laboratory glassware including beakers (up to 2000 mL), Erlenmeyer flasks, and round-bottom flasks placed directly on the heating surface. Its open-platform design supports vessels with flat, non-magnetic bases — borosilicate glass, stainless steel, or ceramic — but excludes ferromagnetic containers that interfere with magnetic coupling. The device meets CE marking requirements under the EU Low Voltage Directive (2014/35/EU) and Electromagnetic Compatibility Directive (2014/30/EU). While not certified to GLP or GMP Annex 11, its analog control interface and absence of embedded data logging make it suitable for non-regulated environments where audit trails are not mandated. For ISO/IEC 17025-accredited labs, users may document operational parameters manually or via external data loggers.

Software & Data Management

The 78HW-1 operates as a standalone hardware instrument with no embedded firmware, cloud connectivity, or proprietary software dependencies. All controls and status indicators are implemented via discrete electronics and physical user interfaces — eliminating cybersecurity risks associated with networked lab devices. Temperature and speed values are displayed locally only; no data export, USB output, or RS-232 interface is provided. This architecture aligns with institutions prioritizing operational simplicity, IT security policy compliance, and long-term serviceability without vendor lock-in. Calibration verification may be performed using traceable NIST-certified thermometers and tachometers per internal SOPs.

Applications

• Preparation of standardized buffer solutions and calibration standards in analytical chemistry workflows
• Accelerated dissolution testing of pharmaceutical tablets under USP conditions (when paired with appropriate vessels and temperature probes)
• Homogenization of cell culture media and nutrient broths prior to sterilization
• Controlled heating and mixing during titration setup, colorimetric assays, and redox reactions
• Viscosity screening of low-to-medium viscosity Newtonian fluids (e.g., aqueous polymer solutions, surfactant micellar systems) when used with calibrated stir bars and rotational speed correlation protocols
• General-purpose benchtop mixing in university teaching labs where reliability, ease of use, and cost-efficiency are primary selection criteria

FAQ

Is the 78HW-1 compatible with closed-vessel reactions such as sealed digestion tubes?
No — the device requires direct magnetic coupling between the internal stir bar and the drive magnet. Sealed vessels with thick walls or metallic shielding will attenuate the magnetic field and prevent reliable rotation.
Can the unit maintain temperature accuracy in a draft-prone fume hood environment?
Ambient airflow exceeding 0.5 m/s may reduce thermal stability by >1.0 °C. For critical applications, use within still-air enclosures or add optional acrylic draft shields (not supplied).
What is the maximum recommended volume for uniform heating and mixing?
For optimal thermal uniformity and vortex formation, limit working volumes to ≤1500 mL in standard 2000-mL beakers. Larger volumes require extended equilibration time and may exhibit radial temperature gradients.
Does the device support external temperature probe feedback for jacketed reactor control?
No — temperature regulation is based solely on the built-in plate sensor. External probe input is not supported.
Are replacement stir bars available with higher torque ratings for viscous samples?
Standard PTFE-coated stir bars included are rated for viscosities up to 1000 mPa·s at 1000 rpm. Higher-torque elliptical or cross-shaped stir bars (sold separately) extend capability to ~5000 mPa·s under optimized conditions.