Great Wall DLSB-5/20B Low-Temperature Cooling Circulator

Overview

The Great Wall DLSB-5/20B Low-Temperature Cooling Circulator is an engineered solution for precise, stable, and continuous thermal management in laboratory-scale chemical synthesis, rotary evaporation, and reaction calorimetry applications. Designed as a performance-optimized successor to the DLSB-5/20 series, it delivers enhanced energy efficiency and operational reliability while maintaining full compatibility with standard benchtop equipment—including single or dual 2 L rotary evaporators and 1–5 L jacketed reactors. Its refrigeration system operates on the vapor-compression cycle, utilizing a hermetically sealed Embraco piston compressor, air-cooled finned condenser with oxygen-free copper tubing, capillary tube expansion device, and a submerged 304 stainless steel coil evaporator integrated directly into the reservoir. This architecture ensures robust heat transfer, mechanical resilience against cryogenic stress (e.g., carrier fluid freezing), and long-term stability under continuous duty cycles.

Key Features

• High-Reliability Refrigeration Core: Embraco-sourced hermetic piston compressor—imported, lubricated-for-life, and rated for >20,000 hours of operation—ensures consistent cooling output and minimal acoustic emission (<58 dB(A)).
• Corrosion-Resistant Fluid Pathway: Entire circulation loop—including reservoir, evaporator, pump housing, and inlet/outlet ports—is constructed from ASTM A240 304 stainless steel; compatible with water, ethanol/water mixtures, and ethylene glycol-based heat transfer fluids.
• Intelligent Digital Control: CE-certified LCD controller with Pt100 sensor input provides real-time temperature monitoring at 0.1 °C resolution, programmable setpoint control, and visual alarm indicators for all safety interlocks.
• Comprehensive Safety Architecture: Multi-layer protection includes compressor delay start (to prevent liquid slugging), overcurrent cutoff, high-pressure switch, thermal overload relay, ground-fault detection, and automatic shutdown upon sensor failure or abnormal ambient conditions.
• Industrial Communication Ready: Standard RS485 interface with MODBUS RTU protocol enables integration into centralized lab monitoring systems (e.g., LabVantage, DeltaV, or custom SCADA), supporting remote parameter setting, status polling, and event logging.
• Eco-Conscious Refrigerant System: Charged exclusively with R404A—a zero-ozone-depletion-potential (ODP = 0), non-CFC hydrofluorocarbon blend—meeting EU F-Gas Regulation (EU No. 517/2014) and U.S. EPA SNAP program requirements for laboratory-grade chillers.

Sample Compatibility & Compliance

The DLSB-5/20B is validated for use with common laboratory heat-transfer media including deionized water, 30–50% aqueous ethylene glycol solutions, and ethanol/water blends. Its reservoir design accommodates up to 5 L of fluid, with clear fill-level markings conforming to IEC 61000-6-3 EMC emission limits and IEC 61000-6-2 immunity standards. All electrical components—including Schneider contactors, circuit breakers, and terminal blocks—meet IEC 60947-4-1 and UL 508 industrial control equipment specifications. The unit carries full CE marking per Directive 2014/35/EU (Low Voltage Directive), 2014/30/EU (EMC Directive), and 2009/125/EC (Ecodesign). It supports GLP-compliant workflows through configurable alarm logging, user-accessible service history, and traceable firmware version reporting via MODBUS register reads.

Software & Data Management

While the DLSB-5/20B does not include proprietary PC software, its MODBUS RTU implementation allows seamless integration with third-party data acquisition platforms. Key registers expose real-time values—including actual bath temperature, setpoint, compressor run time, fault codes (e.g., E01 = high pressure, E03 = sensor open), and cumulative operating hours—enabling automated audit trails required under FDA 21 CFR Part 11 for electronic records in regulated environments. Optional Modbus-to-Ethernet gateways permit connection to cloud-based lab infrastructure, supporting predictive maintenance alerts based on runtime trends and thermal load profiling across multi-unit deployments.

Applications

• Condenser cooling for rotary evaporation of thermolabile compounds (e.g., natural product isolates, pharmaceutical intermediates)
• Temperature control of jacketed glass reactors during exothermic Grignard, lithiation, or hydrogenation reactions
• Stabilization of laser sources, spectrophotometer detectors, or NMR probe preamplifiers requiring sub-ambient thermal sinks
• Supporting cryo-milling or low-temperature crystallization studies where bath stability ±2°C suffices
• Integration into automated synthesis platforms (e.g., ChemSpeed, Unchained Labs) as a distributed cooling node

FAQ

What is the minimum ambient temperature for reliable operation?
The unit is rated for ambient conditions between 5°C and 35°C. Operation below 5°C may impair oil return in the compressor and trigger false high-pressure faults.
Can the DLSB-5/20B be used with flammable solvents like acetone or THF?
No. While the fluid path is chemically resistant, the unit is not explosion-proof (ATEX/IECEx certified) and lacks intrinsically safe electronics. Use only with non-flammable, low-vapor-pressure heat transfer fluids.
Is remote firmware update supported?
No. Firmware updates require physical access and must be performed by authorized service personnel using dedicated diagnostic tools.
Does the unit support external temperature feedback control (e.g., reactor jacket sensor input)?
No. It operates in bath temperature control mode only; external PID cascading is not implemented in the base controller.
What maintenance intervals are recommended?
Visual inspection every 6 months; condenser coil cleaning (compressed air) every 3 months in dusty environments; refrigerant charge verification every 24 months by certified HVAC-R technician.