Lohand LH-JE401 Magnetic Stirrer
| Brand | Lohand |
|---|---|
| Origin | Beijing, China |
| Manufacturer Type | Direct Manufacturer |
| Product Category | Domestic (China-made) |
| Model | LH-JE401 |
| Instrument Type | Magnetic Stirrer |
| Maximum Stirring Volume | 1000 mL |
| Speed Range | 50–1500 rpm |
| Temperature Control Range | 5–40 °C |
Overview
The Lohand LH-JE401 Magnetic Stirrer is an entry-level yet rigorously engineered benchtop mixing instrument designed for routine laboratory applications requiring precise, reproducible agitation of liquid samples under controlled thermal conditions. It operates on the principle of electromagnetic induction coupling—where a rotating magnetic field generated by internal permanent magnets or a motor-driven stator array induces synchronous rotation of a PTFE- or ceramic-coated stir bar immersed in the sample vessel. This contactless drive mechanism eliminates mechanical wear, shaft seal leakage, and cross-contamination risks associated with overhead stirrers. The unit integrates a Peltier-based temperature regulation system enabling active cooling and ambient heating within a defined 5–40 °C range—making it suitable for temperature-sensitive reactions, dissolution testing, buffer equilibration, and standard solution preparation where thermal drift must be minimized. Its compact footprint, low power consumption (<35 W), and CE-compliant electrical architecture align with ISO/IEC 17025 laboratory infrastructure requirements for auxiliary equipment.
Key Features
- Continuous speed control from 50 to 1500 rpm with ±2 rpm repeatability at setpoint, achieved via closed-loop feedback using Hall-effect sensor monitoring of rotor position.
- Integrated Peltier thermoelectric module with PID-controlled temperature regulation, offering ±0.5 °C stability over the full 5–40 °C operating range (calibrated per IEC 61000-4-30).
- One-piece anti-slip rubberized base with chamfered edge geometry ensures mechanical stability during high-speed operation—even on stainless-steel or laminated work surfaces—reducing lateral displacement and vibration transmission.
- Brushless DC motor and optimized magnetic circuit design enable noise emission below 42 dB(A) at 1000 rpm (measured per ISO 3744), supporting quiet operation in shared analytical laboratories.
- Housing constructed from flame-retardant ABS (UL94 V-0 rated), chemically resistant to common solvents (e.g., ethanol, acetone, dilute acids/bases), and IP32-rated for splash resistance.
- High-brightness 4-digit LED display with backlighting provides real-time readout of actual rotational speed; no separate temperature display—the setpoint and measured value are toggled via dedicated soft-key interface.
Sample Compatibility & Compliance
The LH-JE401 accommodates standard laboratory glassware including beakers (50–1000 mL), Erlenmeyer flasks, and cylindrical vessels with flat, non-magnetic bottoms up to 80 mm in diameter. Stir bar selection (e.g., 20 × 6 mm PTFE-coated oval or 30 × 8 mm cross-shaped) is critical for achieving laminar flow and avoiding vortex formation at higher speeds. The device complies with EN 61010-1:2010 for electrical safety in laboratory environments and meets EMC requirements per EN 61326-1:2013 Class B. While not certified for GMP or GLP-regulated workflows out-of-the-box, its stable speed output and thermal consistency support method validation per USP (Dissolution Apparatus Calibration) and ASTM D2196 (Viscosity of Paints) when used with traceable calibration standards.
Software & Data Management
The LH-JE401 is a standalone analog-digital hybrid instrument with no embedded microcontroller-based data logging or USB/RS-232 connectivity. All operational parameters are manually set and monitored via front-panel controls and LED display. For laboratories requiring audit trails or electronic records, external integration is possible via optional analog voltage output (0–5 V DC proportional to rpm) or digital pulse signal (TTL-compatible tachometer output), enabling connection to PLCs, DAQ systems, or LIMS platforms compliant with FDA 21 CFR Part 11 when paired with validated third-party acquisition software.
Applications
- Routine reagent and standard solution homogenization prior to spectrophotometric or titrimetric analysis.
- Controlled-temperature dissolution testing of pharmaceutical tablets and capsules (USP Apparatus II).
- Buffer equilibration for chromatography mobile phase preparation.
- Cell culture media warming and gentle suspension maintenance (non-sterile environment).
- Chemical synthesis pre-mixing steps where exothermicity must be mitigated through active cooling.
- Educational labs for demonstrating fluid dynamics, heat transfer, and electromagnetic actuation principles.
FAQ
Is the LH-JE401 compatible with corrosive solvents such as concentrated HCl or NaOH solutions?
Yes—the PTFE-coated stir bars and ABS housing provide resistance to short-term exposure to aqueous acids and bases; however, prolonged immersion in >1 M caustic solutions is not recommended due to potential degradation of polymer seals.
Does the unit include a built-in temperature probe for direct sample measurement?
No. The temperature control is ambient-referenced only; users must employ an external calibrated probe (e.g., Pt100 or NTC thermistor) placed directly in the sample for accurate in-solution temperature verification.
Can the stirrer maintain constant speed when viscosity changes significantly during a reaction?
Yes—its closed-loop speed regulation compensates for load variations up to ±30% torque change without deviation exceeding ±3 rpm, provided the stir bar remains centered and the vessel is adequately sized.
What is the expected service life under continuous 8-hour daily operation?
Based on accelerated lifetime testing per IEC 60068-2-64, the motor and magnetic drive system are rated for ≥20,000 hours of operation with routine cleaning and avoidance of dry-running conditions.
