Shanghai-made 90-1 Constant-Temperature Magnetic Stirrer with Digital Control | Compatible Models: 85-1, 85-2, 90, 90-2, 90-3
| Origin | Shanghai, China |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Product Origin | Domestic (China) |
| Models | 85-1 / 85-2 / 90 / 90-1 / 90-2 / 90-3 |
| Stirring Capacity | 20–3000 mL |
| Speed Range | 0–2400 rpm (85-1) |
| Temperature Control Range | Ambient to 150 °C (90-1 & derivatives) |
| Heating Power | 0–350 W |
| Timer Function | 0–120 min (90-2 & 90-3) |
| Display | Digital LED for speed, temperature, and timer |
| Housing Material | Die-cast aluminum alloy |
| Stir Bar Compatibility | Standard PTFE-coated or stainless steel rods |
| Motor Type | Brushless DC motor with high-torque neodymium magnets |
Overview
The 90-1 Constant-Temperature Magnetic Stirrer is a precision-engineered laboratory instrument designed for reproducible mixing, heating, and thermal stabilization of liquid samples in research, quality control, and educational settings. Operating on the principle of magnetic coupling—where a rotating permanent magnet beneath the work surface induces synchronous rotation of a magnetic stir bar immersed in the sample—the device delivers consistent torque transfer without mechanical shaft penetration. Unlike gear-driven or overhead stirrers, this design eliminates contamination risk, simplifies cleaning, and ensures leak-proof operation. The 90-1 variant integrates independent digital PID-based temperature regulation with adjustable heating power (0–350 W), enabling precise thermal management across a broad range (ambient to 150 °C). Its brushless DC motor, paired with high-strength neodymium magnets, provides stable rotational output over extended duty cycles—even at elevated viscosities—and supports continuous operation under GLP-compliant workflows.
Key Features
- Digital dual-parameter control interface with simultaneous real-time display of stirring speed (rpm), set temperature (°C), and elapsed/remaining timer duration (min)
- Brushless DC motor architecture ensuring low electromagnetic interference, minimal heat generation, and service life exceeding 10,000 hours
- Die-cast aluminum housing with sealed electronics compartment—resistant to chemical splashes and thermal stress during prolonged heating
- Stainless steel stir bars (included) with PTFE or glass coating for compatibility with acidic, alkaline, and organic solvents
- Over-temperature protection circuitry that automatically deactivates heating when sensor readings exceed user-defined safety thresholds
- Three operational variants: basic (85-1/85-2), thermostatic (90-1), timer-equipped (90-2), and bidirectional timer-controlled (90-3) for advanced protocol automation
Sample Compatibility & Compliance
The stirrer accommodates standard laboratory glassware—including beakers (50–2000 mL), Erlenmeyer flasks, and reaction vessels—with optimal performance observed in aqueous, ethanolic, glycerol-based, and low-viscosity polymer solutions (up to ~500 mPa·s). It complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements for electromagnetic compatibility (EMC Directive 2014/30/EU). While not certified to ISO/IEC 17025 or FDA 21 CFR Part 11 out-of-the-box, its digital logging capability (via optional RS232/USB interface on upgraded firmware versions) supports audit-ready data capture when integrated into validated systems under GMP or GLP environments.
Software & Data Management
The base unit operates via embedded microcontroller firmware with non-volatile memory for parameter retention after power cycling. Optional communication modules enable serial data export (ASCII format) of time-stamped speed, temperature, and status flags to external PCs or LIMS platforms. Firmware supports configurable alarm thresholds and auto-shutdown triggers—critical for unattended overnight reactions. Though no proprietary GUI is bundled, ASCII logs are compatible with common spreadsheet and statistical analysis tools (e.g., Excel, Python pandas, JMP) for trend analysis and SOP documentation. Audit trail functionality requires external timestamping and user authentication layers per 21 CFR Part 11 Annex 11 guidelines.
Applications
This stirrer serves core functions across analytical, preparative, and process-development laboratories: dissolution testing per USP , buffer equilibration in HPLC mobile phase preparation, catalyst suspension in homogeneous catalysis studies, enzyme kinetics assays requiring thermal stabilization, and microbial culture media homogenization. In industrial QC labs, it supports ASTM D1298 (density of crude oil), ISO 3104 (kinematic viscosity), and pharmacopeial extractive preparations. Educational institutions utilize its intuitive interface for teaching fluid dynamics principles, Arrhenius rate dependence, and closed-loop control theory.
FAQ
What is the maximum recommended viscosity for stable stirring at 1250 rpm?
For consistent vortex formation and temperature uniformity, the system is optimized for Newtonian fluids up to 500 mPa·s at full speed; higher viscosities require reduced rpm or larger-diameter stir bars.
Can the 90-1 operate without active heating while maintaining speed control?
Yes—temperature control and stirring functions are fully decoupled; users may disable heating while retaining digital speed regulation and timer functionality.
Is calibration traceable to national standards?
The unit ships with factory calibration certificates for temperature (±1.5 °C at 100 °C) and speed (±2% of setpoint); third-party calibration services are available using NIST-traceable thermistors and optical tachometers.
What maintenance intervals are recommended for long-term reliability?
Annual inspection of thermal sensor contact integrity and magnet alignment is advised; no routine lubrication or belt replacement is required due to brushless motor design.
Are replacement stir bars and housings available as spare parts?
Yes—standardized 20 mm and 30 mm PTFE-coated stir bars, as well as die-cast aluminum top plates and control boards, are stocked for all listed models.
