The Great Wall DLSB-5/20A Low-Temperature Circulating Chiller

Overview

The Great Wall DLSB-5/20A Low-Temperature Circulating Chiller is an engineered solution for precise thermal management in laboratory and pilot-scale applications requiring stable sub-ambient cooling. Based on vapor-compression refrigeration cycle architecture, it integrates a hermetically sealed Embraco piston compressor with an optimized air-cooled condenser and a submerged 304 stainless steel coil evaporator—designed to deliver consistent heat extraction across a wide operational temperature span from –20 °C to +25 °C. Its reservoir-integrated evaporator configuration ensures mechanical integrity even under partial freezing conditions of the heat transfer fluid, eliminating risk of coil rupture during low-temperature operation—a critical reliability feature for continuous-duty cryogenic circulation systems.

Key Features

• Embraco hermetic piston compressor: Delivers long service life, low acoustic emission (<65 dB(A)), and high volumetric efficiency under variable load conditions.
• Air-cooled finned-tube condenser with oxygen-free copper spiral tubing: Enhances convective heat transfer coefficient by >25% versus conventional straight-tube designs; proprietary expansion joint technology enables simplified maintenance without brazing or welding.
• Submerged 304 stainless steel coil evaporator: Fully immersed within the 5 L SUS304 reservoir; eliminates thermal stress-induced fatigue failure during repeated freeze-thaw cycles of ethylene glycol/water or ethanol-based coolants.
• CE-certified digital LCD controller: Real-time display of setpoint, actual bath temperature (±0.1 °C resolution), and system status; supports dual-mode operation (constant temperature or ramp-hold profiles).
• Industrial-grade electrical architecture: Schneider contactors, circuit breakers, and thermal overload relays ensure compliance with IEC 60947-4-1 and UL 508 standards for continuous 24/7 operation.
• R404A refrigerant: Non-ozone-depleting (ODP = 0), compliant with EU F-Gas Regulation (EU No. 517/2014) and EPA SNAP program requirements for laboratory chillers.

Sample Compatibility & Compliance

The DLSB-5/20A circulates heat transfer fluids—including aqueous glycol mixtures, ethanol, and silicone oils—through external equipment such as rotary evaporators, spectrophotometer jackets, reaction calorimeters, and vacuum manifold traps. Its R1/2″ BSP fluid ports and compatible Φ13×Φ9 mm silicone tubing support leak-tight connections under sustained pressure (0.4 bar max). The unit meets CE marking requirements per Directive 2014/35/EU (Low Voltage Directive) and 2014/30/EU (EMC Directive), with full technical documentation available for GLP/GMP audit trails. All safety interlocks—including delayed compressor restart, high-pressure cutoff, ground-fault detection, and thermal cutout—are independently validated per EN 61000-6-2 and EN 61000-6-4.

Software & Data Management

Equipped with standard RS485 serial interface and native MODBUS RTU protocol support, the chiller enables seamless integration into centralized lab automation platforms (e.g., LabVIEW, DeltaV, or custom SCADA systems). Remote setpoint adjustment, real-time temperature logging, and alarm event timestamping are accessible via ASCII command set. While no proprietary software is bundled, the device supports third-party data acquisition through industry-standard Modbus function codes (03h, 06h, 10h), facilitating traceable temperature records compliant with FDA 21 CFR Part 11 when paired with validated host systems. Audit trail generation—including operator ID, parameter change time, and pre/post-value states—is achievable via external historian servers.

Applications

• Condenser cooling for rotary evaporation at controlled sub-zero temperatures to improve solvent recovery of thermolabile compounds.
• Thermal stabilization of NMR probe preamplifiers and laser diode mounts requiring ±0.5 °C stability over extended periods.
• Circulating coolant supply for HPLC column ovens operating below ambient to enhance peak resolution in reversed-phase separations.
• Reaction temperature control in jacketed glass reactors during exothermic Grignard or lithiation steps.
• Calibration baths for PT100 and thermistor probe verification across –20 °C to +25 °C range per ISO/IEC 17025 requirements.

FAQ

What is the minimum ambient temperature required for reliable operation?
The unit is rated for ambient conditions between 5 °C and 35 °C. Operation below 5 °C may impair oil return to the compressor and reduce refrigerant mass flow, potentially triggering high-pressure shutdown.

Can the chiller maintain –20 °C continuously with a 5 L glycol/water bath?
Yes—when loaded with 30% v/v ethylene glycol/water mixture and operated within specified ambient limits (≤30 °C, ≤70% RH), the unit achieves steady-state –20 °C with <±0.8 °C fluctuation over 8-hour cycles.

Is the reservoir volume adjustable or expandable?
No—the 5 L capacity is fixed and structurally integrated with the evaporator assembly; external reservoir extension is not supported due to hydraulic and thermal design constraints.

Does the controller support password-protected parameter modification?
Yes—three-tier access levels (operator, engineer, administrator) are configurable via LCD menu; parameter changes require valid PIN entry and generate internal log entries with timestamps.

What certifications accompany the unit for international shipment?
Each unit ships with CE Declaration of Conformity, RoHS compliance statement, and R404A refrigerant handling documentation compliant with ISO 5149-2:2014 for refrigeration system safety.