YUHUA DLSB-5/30 Cryogenic Constant-Temperature Circulator

Overview

The YUHUA DLSB-5/30 Cryogenic Constant-Temperature Circulator is a mechanically refrigerated, closed-loop liquid circulation system engineered for precise thermal management in demanding laboratory environments. It operates on vapor-compression refrigeration principles using a high-efficiency, hermetically sealed compressor and optimized R23/R508B dual-stage refrigerant circuitry to achieve stable operation at −30 °C under no-load conditions. Unlike open-bath chillers, this unit maintains fluid integrity through a fully sealed circulation path, minimizing evaporation loss, contamination risk, and temperature drift—critical for extended-duration experiments requiring reproducible thermal profiles. Its primary function is to supply temperature-stabilized coolant to external equipment—including rotary evaporators, vacuum freeze dryers, electron microscopes, X-ray diffractometers, laser systems, and magnetron sputtering chambers—thereby enabling low-temperature reaction control, cryogenic sample conditioning, and instrument thermal regulation without direct immersion.

Key Features

• Hermetically sealed, imported compressor assembly with dual-refrigerant cascade architecture for reliable sub-zero performance down to −30 °C
• Corrosion-resistant fluid circuit constructed from stainless steel tubing, fluoropolymer-coated reservoir, and EPDM/NBR-compatible seals to prevent metal ion leaching and preserve coolant purity
• Microprocessor-based digital controller with PID algorithm, real-time temperature display, and programmable setpoint ramping (0.1–10 °C/min)
• High-flow, low-pulsation centrifugal circulation pump delivering 20 L/min at 4–6 m head, compatible with pressure-sensitive instrumentation interfaces
• Integrated internal stirring capability via optional magnetic stirrer mounting platform (accessory), enabling homogenization of bath media without external hardware
• Over-temperature, over-pressure, low-level, and phase-failure protection circuits compliant with IEC 61000-6-2 EMC standards

Sample Compatibility & Compliance

The DLSB-5/30 circulates deionized water, 30% ethylene glycol/water mixtures, or other non-corrosive, low-viscosity heat-transfer fluids compatible with its wetted materials (304 stainless steel, PTFE, FKM). It meets general laboratory safety requirements per ISO 13850 (emergency stop) and UL 61010-1 (electrical safety for lab equipment). While not certified to FDA 21 CFR Part 11 or GMP Annex 11 out-of-the-box, its digital logging interface supports external audit-trail integration when paired with validated third-party data acquisition software. The unit’s temperature stability (±0.2 °C) satisfies ASTM E2234 (standard practice for calibration of temperature-controlled baths) and supports GLP-compliant workflows where traceable thermal validation is required.

Software & Data Management

The DLSB-5/30 features an RS-232 serial port (optional RS-485 adapter available) for bidirectional communication with host PCs or PLCs. Native firmware supports ASCII command protocol for remote setpoint adjustment, real-time temperature readback, status polling (e.g., “COMPRESSOR ON”, “LOW LEVEL ALARM”), and event-triggered data logging. When integrated with LabVIEW™, MATLAB®, or custom Python scripts via PySerial, users can automate temperature ramps, synchronize cooling cycles with analytical instrument triggers (e.g., GC oven start), and export timestamped CSV logs for regulatory review. No proprietary cloud platform is embedded; all data remains on-premise unless explicitly routed through user-configured network infrastructure.

Applications

• Condenser cooling for rotary evaporation of thermolabile compounds below 0 °C
• Thermal stabilization of NMR probe preamplifiers and superconducting magnet cryocooler interfaces
• Heat extraction from high-power UV/VIS lasers and femtosecond oscillator cavities
• Controlled-rate freezing of biological samples in cryopreservation protocols
• Temperature-dependent rheological testing of polymer melts and colloidal dispersions
• Environmental simulation for semiconductor wafer processing tools requiring −30 °C coolant supply

FAQ

What types of heat-transfer fluids are compatible with the DLSB-5/30?

Deionized water, aqueous glycol solutions (≤30% v/v), and synthetic silicone oils with kinematic viscosity <50 cSt at 20 °C. Avoid chlorinated solvents, strong acids/bases, or fluids with flash points <60 °C.
Can the unit maintain −30 °C while delivering 20 L/min to an external device?

Yes—rated cooling capacity of 2733 W at −30 °C ensures thermal load compensation under full flow, provided external system pressure drop remains ≤6 m H₂O and ambient temperature does not exceed 25 °C.
Is the temperature controller validated to NIST-traceable standards?

The internal PT100 sensor is factory-calibrated; users may perform field verification using a NIST-traceable reference thermometer per ASTM E74 or ISO/IEC 17025 procedures.
Does the circulator support continuous unattended operation?

Yes—designed for 24/7 duty cycle with thermal cutouts, auto-restart after power recovery, and alarm-hold functionality that preserves fault state until manual reset.
How often should maintenance be performed?

Compressor oil and filter replacement every 24 months under continuous use; annual inspection of refrigerant charge integrity and seal condition recommended per manufacturer service bulletin SB-DLSB-2023-01.