The Great Wall DLSB-500/30 Low-Temperature Coolant Circulator

Overview

The Great Wall DLSB-500/30 Low-Temperature Coolant Circulator is a mechanically refrigerated, closed-loop liquid circulation system engineered for precise and stable thermal management in laboratory and pilot-scale industrial applications. It operates on vapor-compression refrigeration principles using R404A refrigerant, delivering consistent sub-ambient temperatures from –30 °C to +35 °C with a nominal cooling capacity of 500 W at –30 °C. Unlike open-bath chillers, this unit integrates a 50-liter insulated reservoir with a high-efficiency circulation pump and a robust refrigeration module—enabling continuous, contamination-free coolant delivery to external equipment such as rotary evaporators, bioreactors, chemical reaction vessels (300–1000 L), vacuum freeze dryers, and thin-film deposition systems. Its design prioritizes thermal stability, long-term operational reliability, and compatibility with GxP-aligned workflows where temperature reproducibility and system integrity are critical.

Key Features

• Stainless steel (AISI 304) wetted components—including reservoir, pump head, and fluid pathways—resist corrosion, oxidation, and low-temperature embrittlement, ensuring compatibility with deionized water and common glycol-water mixtures.
• Modular architecture separates the refrigeration unit from the insulated reservoir, facilitating safe and ergonomic coolant filling, maintenance access, and thermal decoupling between heat rejection and process cooling zones.
• Variable-speed circulation pump with flow adjustment dial (0–25 L/min) supports pressure- and flow-sensitive applications, including jacketed reactor cooling and condenser thermal load matching.
• Comprehensive safety suite includes high-pressure cut-off switch, compressor overheat protection, motor overcurrent detection, and real-time fault logging—meeting IEC 61000-4 electromagnetic compatibility requirements.
• Intuitive digital controller with keypad lock function prevents unauthorized parameter changes—a functional prerequisite for GLP-compliant environments and multi-user laboratories.
• Air-cooled condenser design eliminates dependency on municipal water supply, reducing infrastructure demands and enabling deployment in water-constrained or mobile lab settings.

Sample Compatibility & Compliance

The DLSB-500/30 is validated for use with deionized water and aqueous ethylene glycol solutions (up to 30% v/v), minimizing scaling, microbial growth, and freezing-point depression-related instability. Its materials of construction comply with USP Class VI and FDA 21 CFR 177.2600 for indirect food contact, supporting applications in pharmaceutical process development and food-grade R&D. While not intrinsically certified to UL/CSA standards, the unit bears CE marking per Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), and its quality management system adheres to ISO 9001:2015. Documentation packages include factory calibration reports traceable to NIST-equivalent national standards and full electrical schematics for audit readiness.

Software & Data Management

This model features a standalone microprocessor-based controller with local setpoint programming, real-time temperature display (±0.2 °C accuracy), and alarm status indicators. Although it does not include Ethernet or USB connectivity, optional RS-485 Modbus RTU interface kits are available for integration into centralized SCADA or LabVantage LIMS environments. All operational events—including temperature deviations exceeding ±1.5 °C for >60 seconds, pump stoppages, and safety interlock activations—are logged with timestamps and retained for ≥10,000 cycles. Audit trail functionality satisfies basic ALCOA+ data integrity criteria when paired with procedural controls per Annex 11 and FDA Guidance for Industry on Computerized Systems Used in Clinical Trials.

Applications

• Cooling jackets of 300–1000 L glass or stainless steel reactors during exothermic synthesis, crystallization, or polymerization.
• Condenser temperature control in rotary evaporation systems processing heat-sensitive APIs or volatile solvents (e.g., dichloromethane, ether).
• Thermal stabilization of vacuum freeze dryers during primary drying phases requiring precise shelf temperature control.
• Supporting cryogenic processes in materials science labs—including sputtering targets, MBE systems, and superconductivity testing setups.
• Long-duration storage of biological reagents, cell cultures, or diagnostic standards at controlled sub-zero conditions in academic and clinical research facilities.

FAQ

What coolant fluids are recommended for the DLSB-500/30?

Deionized water is standard for operation down to –5 °C; for lower temperatures, a mixture of deionized water and USP-grade ethylene glycol (20–30% v/v) is required to prevent freezing and maintain viscosity within pump specifications.
Can this circulator be integrated with third-party reactors or analytical instruments?

Yes—via standard 1/2″–3/4″ NPT inlet/outlet ports and compatible flexible tubing (recommended: PTFE-reinforced silicone or EPDM). Optional pressure sensors and flow meters can be added for closed-loop feedback control.
Is remote monitoring or data export supported out-of-the-box?

No native network interface is included; however, the optional RS-485 Modbus RTU expansion module enables bidirectional communication with PLCs, DCS platforms, or custom Python-based monitoring scripts.
What maintenance intervals are specified for long-term reliability?

Compressor oil inspection every 12 months; refrigerant leak check annually; reservoir cleaning and coolant replacement every 6 months under continuous operation—per manufacturer’s Maintenance Log Template (included in documentation kit).
Does the unit meet regulatory requirements for pharmaceutical manufacturing environments?

It complies with core mechanical and electrical safety directives (CE/LVD/EMC) and supports GMP-aligned validation protocols (IQ/OQ/PQ), though formal 21 CFR Part 11 compliance requires supplementary procedural controls and electronic signature implementation at the facility level.