The Great Wall DHJF-1020 Cryogenic Stirred Reaction Bath

Overview

The Great Wall DHJF-1020 Cryogenic Stirred Reaction Bath is an engineered low-temperature laboratory system designed for precise thermal control and mechanical agitation of reaction mixtures under sustained sub-zero conditions. It operates on a single-stage compression condensation refrigeration cycle—optimized for extended stability in the −100 °C to −60 °C range—enabling applications such as cryogenic synthesis, low-temperature catalysis, polymerization initiation, and solvent crystallization studies. Unlike conventional recirculating chillers, the DHJF-1020 integrates a built-in high-torque magnetic stirrer and a large-capacity stainless-steel bath vessel, permitting direct immersion of reaction flasks up to 5 L while maintaining uniform thermal distribution and minimizing temperature gradients across the working volume. Its architecture supports continuous operation in ambient environments between 5 °C and 25 °C, with thermal stability maintained within ±2 °C under steady-state load.

Key Features

• Single-stage cryogenic refrigeration system engineered for reliable operation down to −100 °C, incorporating high-efficiency compressors sourced from Tier-1 manufacturers in the United States, Germany, and France
• Integrated magnetic stirring mechanism with adjustable speed control (0–1200 rpm), enabling homogeneous mixing without introducing mechanical seals or shaft penetrations into the bath
• Bath reservoir constructed from 304 stainless steel and chemically resistant polymer linings to withstand prolonged exposure to low-temperature solvents including liquid nitrogen-cooled baths, chlorinated hydrocarbons, and fluorinated media
• Digital PID temperature controller with membrane keypad interface and LED display for real-time setpoint entry, process monitoring, and deviation alerting
• Robust structural housing fabricated from cold-rolled steel with electrostatic epoxy powder coating for corrosion resistance and mechanical durability in shared laboratory environments
• Three-phase 380 V, 50 Hz power input compatible with industrial-grade electrical infrastructure; includes overcurrent protection, compressor high-pressure cutoff, and dry-run safety interlocks

Sample Compatibility & Compliance

The DHJF-1020 accommodates standard laboratory glassware—including round-bottom flasks (up to 5000 mL), jacketed reactors, and immersion condensers—via its 280 mm opening diameter and 300 mm internal bath depth. The system complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements for electromagnetic compatibility (EMC) and low-voltage directive conformity. While not certified to ISO/IEC 17025 or GLP-specific validation protocols out-of-the-box, its digital temperature logging capability (via optional RS485/Modbus output) supports integration into validated workflows compliant with FDA 21 CFR Part 11 when paired with qualified data acquisition software. Users performing GMP-regulated synthesis should implement periodic calibration using NIST-traceable cryogenic thermometers and document thermal uniformity mapping per ASTM E2251-22.

Software & Data Management

The DHJF-1020 features a standalone microprocessor-based controller with non-volatile memory for storing up to 10 user-defined temperature profiles and runtime logs. Optional communication modules enable Modbus RTU over RS485 for integration with LabVIEW, MATLAB, or SCADA platforms. When connected to a host PC via serial-to-USB adapter, third-party software can extract timestamped temperature readings at 1-second intervals, supporting audit-ready records for method development and process qualification. No proprietary cloud service or vendor-hosted platform is required; all data remains under local institutional control. Firmware updates are delivered via USB flash drive and validated through checksum verification prior to installation.

Applications

• Cryogenic Grignard and organolithium reagent preparation requiring strict thermal control below −80 °C
• Low-temperature Diels–Alder and asymmetric epoxidation reactions where selectivity is thermally sensitive
• Controlled precipitation of metal–organic frameworks (MOFs) and coordination polymers
• Stability testing of pharmaceutical intermediates under accelerated cold stress conditions
• Calibration reference baths for infrared spectroscopy sample cells and cryostat-mounted detectors
• Pre-cooling of gas chromatography inlet systems and thermal desorption units

FAQ

What is the lowest operational temperature achievable with the DHJF-1020?

The system is rated for continuous operation at −100 °C, with verified cooling capacity of 180 W at that setpoint. Performance below −100 °C is not specified or guaranteed.
Can the DHJF-1020 be used with flammable solvents such as diethyl ether or THF?

Yes—provided appropriate ventilation, explosion-proof auxiliary equipment (e.g., spark-free stir bars and intrinsically safe controllers), and adherence to NFPA 45 laboratory safety standards for flammable liquid handling.
Is external coolant circulation supported?

No—the DHJF-1020 is a self-contained bath system; it does not feature external jacket ports or pump-out fittings for secondary loop integration.
How often does the refrigerant require servicing?

Under normal operation and proper ambient conditions (5–25 °C), the sealed refrigeration circuit requires no scheduled maintenance for ≥8 years; annual visual inspection of condenser coil cleanliness and electrical connections is recommended.
Does the unit include calibration documentation?

Factory calibration certificates are provided upon request at time of order; these include as-found/as-left data against traceable references at −60 °C, −80 °C, and −100 °C.