ZiQi DLSB-30/20 Cryogenic Constant-Temperature Circulator

Overview

The ZiQi DLSB-30/20 Cryogenic Constant-Temperature Circulator is a mechanically refrigerated, closed-loop liquid circulation system engineered for precise thermal management in life science and analytical laboratories. Operating on vapor-compression refrigeration principles, it delivers stable, low-temperature coolant—typically ethylene glycol/water or ethanol/water mixtures—to external equipment requiring active heat extraction. Its core function is to maintain a constant bath temperature within ±0.2 °C across a range from −20 °C up to ambient conditions, enabling reproducible low-temperature reaction environments, condenser cooling for rotary evaporation, and thermal stabilization of sensitive instrumentation such as electron microscopes, laser sources, X-ray diffractometers, and vacuum deposition systems. Unlike open-bath chillers, the DLSB-30/20 features a fully sealed circulation loop with corrosion-resistant wetted materials, minimizing evaporation loss, contamination risk, and maintenance frequency—critical for GLP-compliant workflows and long-duration unattended operation.

Key Features

• Hermetically sealed, imported high-efficiency compressor delivering consistent cooling performance at −20 °C with low vibration and acoustic emission
• 30-liter stainless-steel-coated reservoir with integrated level sensor and overflow protection
• Corrosion-resistant circulation pump constructed with PTFE-sealed ceramic shaft and EPDM diaphragm, compatible with common organic coolants and aqueous solutions
• Microprocessor-based PID temperature controller with digital LED display, real-time setpoint adjustment, and auto-recovery after power interruption
• Insulated cabinet with reinforced polyurethane foam (≥40 mm thickness) ensuring minimal thermal leakage and energy efficiency
• Front-accessible service panel for routine maintenance; no tools required for filter replacement or coolant top-up
• Over-temperature, over-pressure, and dry-run protection circuits compliant with IEC 61000-6-2 EMC standards

Sample Compatibility & Compliance

The DLSB-30/20 is designed for use with non-aggressive heat-transfer fluids—including 30–50% aqueous ethylene glycol, ethanol, or methanol solutions—commonly employed in rotary evaporators (e.g., 20 L capacity units), cold traps, cryo-milling jackets, and vacuum freeze dryers. It meets general laboratory safety requirements per EN 61010-1:2010 (Safety Requirements for Electrical Equipment for Measurement, Control, and Laboratory Use). While not certified to ISO/IEC 17025 or FDA 21 CFR Part 11 out-of-the-box, its digital temperature logging capability (via optional RS485 interface) supports audit-ready data capture when integrated into validated systems under GMP/GLP frameworks. The unit operates reliably in ambient conditions up to 32 °C and relative humidity ≤80% (non-condensing), making it suitable for standard university labs, pharmaceutical QC suites, and materials research facilities.

Software & Data Management

The DLSB-30/20 includes embedded firmware supporting manual temperature programming and real-time monitoring via front-panel interface. For advanced integration, an optional RS485 serial port enables connection to LabVIEW, MATLAB, or custom SCADA platforms using Modbus RTU protocol. This allows remote setpoint control, continuous temperature logging, alarm event timestamping, and synchronization with other lab assets—facilitating compliance with ALCOA+ data integrity principles. Though the base unit does not include built-in data storage or electronic signature functionality, its deterministic response time (<30 s to reach ±0.5 °C of setpoint from standby) and repeatable stability profile support retrospective validation studies per ASTM E2500 and USP .

Applications

• Coolant supply for 20 L rotary evaporators during solvent removal at sub-ambient temperatures to prevent thermal degradation of thermolabile compounds
• Thermal regulation of cryo-microtomes and tissue embedding stations in histopathology labs
• Condenser cooling in vacuum distillation and fractional crystallization setups
• Stabilization of laser diodes, CCD detectors, and NMR probe preamplifiers requiring vibration-free, low-noise thermal sinks
• Temperature-controlled feed for environmental simulation chambers and accelerated aging test rigs
• Supporting low-temperature catalysis, polymerization kinetics, and superconductivity screening experiments in academic and industrial R&D

FAQ

What is the minimum achievable temperature with a full 30 L coolant load?
The DLSB-30/20 achieves −20 °C under no-load conditions; with a full bath and typical 40% ethylene glycol solution, the practical steady-state minimum is −18.5 °C at ambient ≤25 °C.
Can this circulator be used with deionized water only?
No—pure water is not recommended below 0 °C due to freezing risk and potential corrosion. A minimum 30% antifreeze mixture is required for operation below 5 °C.
Is the pump flow rate adjustable?
Yes—continuous variable flow control (15–35 L/min) is provided via calibrated needle valve on the outlet manifold, maintaining pressure stability up to 4.2 m head.
Does the unit comply with CE marking requirements?
Yes—the DLSB-30/20 carries CE marking per Directive 2014/30/EU (EMC) and 2014/35/EU (LVD), verified by third-party testing per harmonized standards EN 61326-1 and EN 61000-6-3.
What maintenance intervals are recommended?
Compressor oil and refrigerant charge require inspection every 24 months; coolant should be replaced annually or after 1,500 operating hours, whichever occurs first. The inlet filter must be cleaned quarterly.