Leici JB-31 Magnetic Stirrer

Overview

The Leici JB-31 Magnetic Stirrer is a precision-engineered laboratory instrument designed for consistent, controllable, and repeatable mixing of liquid samples across analytical chemistry, electrochemistry, titration, and quality control workflows. Utilizing permanent magnet coupling and optimized motor control, the JB-31 generates reliable rotational torque to drive magnetic stir bars within vessels—enabling homogeneous dispersion without mechanical shaft penetration or contamination risk. Its non-contact stirring mechanism ensures compatibility with sealed or sterile systems and eliminates maintenance associated with overhead stirrer seals or gear wear. The device operates without heating functionality, making it ideal for temperature-sensitive applications where thermal drift must be avoided—such as pH monitoring, redox potential measurements, or kinetic studies requiring ambient thermal stability.

Key Features

• High-resolution LCD display providing real-time visualization of set and actual rotational speed (100–2000 rpm), enabling immediate operational verification and protocol adherence.
• Dual-knob interface for independent adjustment of speed and timer parameters—supporting intuitive, glove-friendly operation in regulated lab environments.
• Multi-mode rotation control: forward, reverse, and alternating direction modes accommodate complex mixing requirements—including suspension re-suspension, emulsion stabilization, and electrode surface renewal during potentiometric titrations.
• Auto-speed recall function retains the last configured rpm setting upon power cycle, reducing setup time and minimizing procedural variability between sequential experiments.
• Ceramic-coated aluminum work surface (145 mm × 145 mm) offers high thermal conductivity, chemical resistance, and mechanical durability—withstanding repeated exposure to acids, bases, and organic solvents typical in wet chemistry labs.
• Integrated triple-electrode mounting bracket enables simultaneous positioning of reference, working, and counter electrodes—facilitating standardized electrochemical cell configurations per ASTM D1125 and ISO 7888 protocols.

Sample Compatibility & Compliance

The JB-31 supports volumetric mixing up to 5 L in standard glass or polymer containers (e.g., beakers, flasks, electrolytic cells). It accommodates three standard stir bar geometries (Φ5×20 mm, Φ7×30 mm, Φ10×60 mm), ensuring stable vortex formation across low- to medium-viscosity aqueous and non-aqueous solutions (μ < 500 mPa·s). The absence of heating elements ensures compliance with applications governed by USP (non-sterile compounding) and ISO/IEC 17025 calibration traceability requirements where thermal input must be excluded from uncertainty budgets. Device construction adheres to IEC 61010-1 safety standards for laboratory electrical equipment, including dielectric strength testing and enclosure IP20 classification.

Software & Data Management

As a standalone benchtop instrument without digital connectivity, the JB-31 does not feature embedded software or data logging capabilities. All operational parameters are manually entered and displayed locally. This architecture aligns with GLP/GMP Annex 11 principles for “simple devices”: no electronic records are generated, eliminating the need for audit trails, user access controls, or 21 CFR Part 11 validation. Laboratory SOPs may document speed settings, timer durations, and stir bar specifications directly in experiment notebooks or LIMS entries—ensuring full traceability without software dependency.

Applications

• Electrochemical analysis: Stable agitation during potentiometric titrations (e.g., chloride determination per ISO 9297), cyclic voltammetry, and conductivity measurements.
• Standard solution preparation: Homogenization of calibration standards for ICP-OES, AAS, and ion chromatography—minimizing density stratification in multi-component matrices.
• Titration support: Continuous mixing during automatic titrator integration, preventing localized pH gradients near indicator electrodes.
• Cell culture media conditioning: Gentle dispersion of powdered supplements (e.g., HEPES, antibiotics) without foaming or shear-induced protein denaturation.
• Environmental water testing: Mixing of EPA Method 300.0 (anions) and 311.1 (phosphate) sample digestates prior to filtration or instrumental analysis.

FAQ

Does the JB-31 include a heating function?
No. The JB-31 is a non-heating magnetic stirrer. It is engineered exclusively for mechanical mixing at ambient temperature.
What stir bar sizes are included with the unit?
Three standard stir bars are supplied: Φ5×20 mm, Φ7×30 mm, and Φ10×60 mm—optimized for volumes ranging from 50 mL to 5000 mL.
Is the timer function programmable in minutes only, or does it support hours?
The timer supports full-range programming from 0 minutes to 99 hours and 59 minutes, with accuracy of ±1 minute per hour.
Can the JB-31 be used inside a fume hood with continuous operation?
Yes. Its plastic housing, ceramic-coated surface, and passive cooling design meet ANSI Z9.5 ventilation compatibility requirements for uninterrupted use under hood airflow.
How is speed stability verified during long-duration experiments?
Speed deviation remains within ±10 rpm over 4-hour intervals—validated per manufacturer’s QC test report (Certificate of Conformance available upon request).