LabTech ES35A Pro Series Magnetic Stirrer

Overview

The LabTech ES35A Pro Series Magnetic Stirrer is an engineered solution for precise, thermally stable, and reproducible mixing in analytical, quality control, and synthetic chemistry laboratories. Designed around a robust Couette-flow principle—where rotational torque from a rotating magnetic field induces laminar motion in paramagnetic stir bars—the ES35A Pro delivers consistent shear profiles across viscous and low-viscosity media. Its integrated heating module operates via resistive heating elements embedded within an aluminum alloy round-bottom flask heating block, enabling direct thermal coupling without external oil baths or mantles. Unlike basic stirrers relying on open-loop temperature control, the ES35A Pro employs a PID-regulated feedback loop with a Pt100 RTD sensor mounted beneath the heating surface, ensuring ±1.5 °C accuracy over the full 20–340 °C operating range (ambient start). The system is purpose-built for applications demanding simultaneous high-speed agitation and elevated temperature stability—such as reflux setups, catalyst activation, polymer dissolution, and accelerated stability testing per ICH Q1 guidelines.

Key Features

• Brushless DC motor with closed-loop electronic speed regulation: maintains set rpm within ±2 rpm across load variations up to 20 L water-equivalent viscosity (up to 500 mPa·s), eliminating drift during reagent addition or exothermic reactions.
• High-coercivity neodymium-iron-boron (NdFeB) magnet assembly: generates >85 mT surface field strength at 10 mm air gap, ensuring reliable engagement of standard PTFE- or glass-coated stir bars—even under high-viscosity or foaming conditions.
• Dual-stage thermal safety architecture: primary control loop limits surface temperature to ≤340 °C; secondary independent bimetallic cut-off triggers irreversible shutdown at 350 °C, compliant with IEC 61010-1:2010 Clause 11.3 for laboratory equipment thermal hazard mitigation.
• IP42-rated sealed enclosure: protects internal electronics from splashes and particulate ingress during routine lab use; housing constructed from flame-retardant ABS (UL94 V-0) with reinforced structural ribs for long-term mechanical integrity.
• Modular heating block system: accepts interchangeable aluminum blocks calibrated for common round-bottom flask sizes (50 mL to 5 L), each featuring precision-machined grooves for optimal thermal contact and uniform heat distribution (ΔT < 3 °C across 100 mm diameter).

Sample Compatibility & Compliance

The ES35A Pro accommodates standard laboratory vessels including borosilicate glass round-bottom flasks (with optional support clamps), beakers, and crystallization dishes. It supports stir bar geometries ranging from 10 × 3 mm micro-bars to 60 × 12 mm heavy-duty elliptical bars, all compatible with common solvents (aqueous, organic, mild acids/bases). Device firmware and hardware design conform to ISO/IEC 17025:2017 requirements for equipment suitability in accredited testing labs. Full traceability documentation—including factory calibration certificates for temperature and speed sensors—is provided. The unit meets CE marking requirements under the Low Voltage Directive (2014/35/EU) and EMC Directive (2014/30/EU), and its electrical insulation system complies with EN 61010-1 Class I protection.

Software & Data Management

While the ES35A Pro operates as a standalone benchtop instrument, it features RS-485 serial interface (Modbus RTU protocol) for integration into centralized lab automation systems. Optional LabTech Link™ software (v3.2+) enables remote parameter setting, real-time monitoring of speed/temperature trajectories, and export of time-stamped CSV logs compliant with FDA 21 CFR Part 11 Annex 11 audit trail requirements—including user ID, timestamp, parameter change, and reason code fields. All stored configurations are retained during power cycling, and EEPROM memory supports ≥100,000 write cycles without degradation.

Applications

• Controlled-temperature synthesis of metal–organic frameworks (MOFs) requiring inert-atmosphere reflux at 120–220 °C.
• Preparation of homogeneous nanoparticle dispersions in ethanol/water mixtures (e.g., TiO₂, SiO₂) under 800–1200 rpm shear for 4–24 h.
• Standardized USP dissolution testing of extended-release tablets using 1–2 L vessels at 37.0 ± 0.5 °C.
• In-process monitoring of enzymatic hydrolysis kinetics in buffered solutions (pH 4.5–7.5) where consistent agitation prevents localized pH gradients.
• GMP-compliant buffer preparation for biopharmaceutical downstream processing, validated per ASTM E2500-13 Annex A3.

FAQ

Does the ES35A Pro support external temperature probes for vessel-integrated measurement?
Yes—via optional PT100 probe input (BNC connector), enabling direct liquid-phase temperature feedback for enhanced process control.
Can the unit operate continuously at maximum speed and temperature?
Rated for continuous operation at 1500 rpm and 340 °C for ≥8 h per cycle; derating recommended above 320 °C for extended service life.
Is calibration documentation included with shipment?
Each unit ships with a NIST-traceable calibration report covering speed (optical tachometer verification) and temperature (dual-point RTD validation at 100 °C and 300 °C).
What maintenance is required for long-term reliability?
Annual inspection of magnet alignment and heater block thermal interface paste; no scheduled lubrication or brush replacement due to brushless motor architecture.
How does the ES35A Pro handle high-viscosity samples like polymer melts?
It sustains target rpm under loads up to 1000 mPa·s when paired with elliptical stir bars and optimized flask geometry—validated per ISO 2555:2019 methodology.