ZiQi DLSB-5/20 Cryogenic Constant Temperature Circulator

Overview

The ZiQi DLSB-5/20 Cryogenic Constant Temperature Circulator is a mechanically refrigerated, closed-loop liquid circulation system engineered for precise thermal management in laboratory-scale chemical, pharmaceutical, and materials science applications. Based on vapor-compression refrigeration using a hermetically sealed compressor, the unit delivers stable sub-ambient coolant supply to external instruments—most commonly rotary evaporators (e.g., 2 L capacity systems), vacuum freeze dryers, magnetic stirrers, and reaction jackets. Its core function is to maintain consistent low-temperature heat exchange without direct immersion of samples in the bath, enabling controlled exothermic reaction quenching, solvent condensation, and cryogenic stabilization of sensitive instrumentation. Designed for continuous operation under ambient conditions up to 25 °C and 80% relative humidity, the DLSB-5/20 integrates thermodynamic efficiency with corrosion-resistant fluid handling architecture—making it suitable for extended use in GLP-compliant laboratories where reproducibility and thermal fidelity are critical.

Key Features

• Hermetically sealed, high-efficiency compressor sourced from internationally recognized OEM suppliers—ensuring long service life and low maintenance intervals
• Microprocessor-based digital temperature controller with LED display; setpoint resolution of 0.1 °C and real-time feedback regulation
• Stainless steel and fluoropolymer-lined circulation loop—resistant to oxidation, hydrolysis, and low-temperature embrittlement
• Adjustable flow rate (0–20 L/min) and pressure head (up to 46 m) to accommodate variable hydraulic resistance across instrument configurations
• Integrated over-temperature, low-flow, and compressor overload protection circuits compliant with IEC 61000-6-2 EMC standards
• Energy-optimized refrigerant circuit design minimizing power consumption while maintaining rated cooling capacity of 1248 W at −20 °C

Sample Compatibility & Compliance

The DLSB-5/20 circulates non-aqueous or inhibited aqueous coolants (e.g., 30% ethylene glycol/water mixture) compatible with standard laboratory tubing (PTFE, silicone, or EPDM). It interfaces seamlessly with common analytical and synthesis platforms including Buchi, IKA, and Heidolph rotary evaporators; Labconco and SP Scientific freeze dryers; and custom jacketed reactors. While not certified to UL/CSA or CE for medical device integration, its electrical safety design conforms to GB 4793.1–2019 (equivalent to IEC 61010-1), and its operational parameters align with ASTM E2912–21 guidelines for laboratory refrigeration equipment qualification. For regulated environments, users may configure audit trails via external data loggers meeting FDA 21 CFR Part 11 requirements.

Software & Data Management

The DLSB-5/20 operates as a standalone analog-digital hybrid system with no embedded firmware or network interface. Temperature setpoints and real-time bath readings are displayed locally via a 4-digit LED panel. For traceable process documentation, optional RS-485 or 0–10 V analog output modules can be integrated with third-party SCADA systems (e.g., LabVIEW, DeltaV, or Siemens Desigo CC) to record timestamps, setpoint deviations, and runtime statistics. All calibration and maintenance logs must be manually entered into laboratory quality management systems per ISO/IEC 17025 clause 7.7.

Applications

• Coolant supply for rotary evaporation of heat-sensitive compounds (e.g., terpenes, alkaloids, and polymer precursors) requiring condenser temperatures below −15 °C
• Thermal stabilization of vacuum manifold manifolds during low-pressure distillation or fractional crystallization
• Secondary cooling loop for laser sources, X-ray diffraction goniometers, and electron microscopy cold stages requiring stable ±0.5 °C control over 8-hour cycles
• Temperature-controlled feedstock pre-chilling in pilot-scale continuous flow reactors (CFR)
• Supporting cold-trap functionality in multi-stage vacuum systems where water-cooled traps exhibit insufficient capture efficiency below −10 °C

FAQ

What coolant fluids are recommended for use with the DLSB-5/20?
Ethylene glycol/water mixtures (20–30% v/v) or commercially formulated low-temperature heat transfer fluids (e.g., Dowtherm J, Therminol LR) are recommended. Pure water is not advised due to freezing risk and corrosion potential.
Can the unit operate continuously for 72 hours or longer?
Yes—when installed in a well-ventilated environment ≤25 °C and loaded within specified hydraulic limits (max. 46 m head, 20 L/min flow), the DLSB-5/20 supports unattended operation exceeding 168 hours per maintenance interval.
Is remote monitoring or Ethernet connectivity available?
No native networking capability exists; however, analog voltage (0–10 V) or Modbus RTU (RS-485) signal outputs can be added via factory-installed options for integration into centralized lab infrastructure.
Does the system meet GMP or ISO 13485 requirements?
The DLSB-5/20 is not certified to GMP or ISO 13485, but its mechanical construction, documentation package (including factory calibration reports), and serviceability support validation per Annex 15 of EU GMP Guidelines when deployed in qualified utility systems.
What is the minimum ambient temperature for reliable startup?
Startup is guaranteed at ambient temperatures ≥10 °C. Below this threshold, compressor oil viscosity increases significantly, potentially delaying refrigerant circulation onset by up to 8 minutes.