GengYu DLSB-5/80 Cryogenic Constant Temperature Circulator

Overview

The GengYu DLSB-5/80 Cryogenic Constant Temperature Circulator is an engineered solution for precise, stable low-temperature liquid circulation in laboratory-scale chemical synthesis, biopharmaceutical storage, and analytical instrumentation support. Operating on vapor-compression refrigeration principles with a Danfoss hermetic compressor and R22 refrigerant, the unit achieves sustained bath temperatures from ambient down to −80 °C (with no-load capability to −82 °C), making it suitable for cryogenic reaction control, cold trap conditioning, and low-temperature sample preservation. Its integrated 5 L open-bath reservoir—dimensioned at Ø220 × 180 mm—functions both as a direct immersion cooling chamber and as a primary source for external closed-loop circulation via a dedicated SUS304 fluid path. The system is designed for continuous duty in controlled environments (5–25 °C ambient, 60–80% RH), meeting baseline operational requirements for GLP-compliant laboratories conducting temperature-sensitive protocols.

Key Features

• Hermetically sealed Danfoss refrigeration compressor ensures long-term reliability, consistent cooling performance, and minimal maintenance intervals under continuous operation.
• SUS304 stainless steel circulation loop—including coil (Ø200 mm inner diameter), bath liner, and fluid pathways—provides inherent resistance to corrosion, oxidation, and low-temperature embrittlement when handling aqueous or organic coolants.
• Digital PT100-based temperature control system with ±0.5 °C stability across the full range (−150 to 100 °C display capability); resolution of 1 °C; electronic setpoint entry and real-time digital readout.
• High-capacity circulation pump (100 W, 20 L/min flow, 4–6 m head, 2 MPa max pressure) supports dual-mode operation: direct bath immersion and external recirculation through rotary evaporators, vacuum freeze dryers, or jacketed reactors (up to 5–10 L capacity).
• Comprehensive safety architecture includes leakage current protection, overcurrent circuit breakers, compressor high-pressure cut-off, pump thermal overload protection, and embedded self-diagnostic firmware for fault logging and operational continuity.
• Epoxy-sprayed steel chassis and nickel-plated copper condenser coils enhance structural durability and thermal efficiency while resisting environmental degradation in shared lab spaces.

Sample Compatibility & Compliance

The DLSB-5/80 circulator is compatible with standard laboratory coolants including water–ethylene glycol mixtures, silicone oils, and low-viscosity synthetic heat transfer fluids rated for −80 °C service. Its open-bath design accommodates common glassware (e.g., round-bottom flasks, test tubes, jacketed vessels) up to Ø195 mm opening diameter. While not certified to IEC 61010-1 or ATEX standards out-of-the-box, optional explosion-proof configurations are available upon request to meet local hazardous area classification requirements (e.g., Class I, Division 2). The unit adheres to general electrical safety norms for laboratory equipment per GB 4793.1 (China) and provides traceable temperature monitoring suitable for internal QA documentation; however, it does not include FDA 21 CFR Part 11–compliant audit trails or electronic signature functionality without third-party software integration.

Software & Data Management

The DLSB-5/80 operates via standalone hardware-based digital control—no embedded OS or network interface is provided. Temperature setpoints, real-time bath readings, and system status (compressor/pump active, fault codes) are displayed on a front-panel LED screen. Data logging requires external recording via analog output (0–5 V or 4–20 mA, configurable per OEM specification) or manual timestamped observation. For labs requiring regulatory-compliant data integrity, integration with validated SCADA platforms (e.g., LabVIEW, DeltaV, or custom Python-based acquisition scripts) is feasible using the unit’s analog signal interface and discrete alarm contacts. Firmware-level diagnostics support basic troubleshooting but do not store historical temperature profiles or event logs internally.

Applications

• Low-temperature chemical synthesis: exothermic reaction control in Grignard, lithiation, or Diels–Alder processes requiring −40 to −80 °C bath stability.
• Support for rotary evaporation: maintaining condenser jacket temperatures below −20 °C to improve solvent recovery efficiency for high-boiling-point analytes.
• Cold trapping in vacuum systems: stabilizing cryo-traps for solvent vapor capture during lyophilization or distillation workflows.
• Biological sample pre-conditioning: equilibrating cell lysates, enzyme solutions, or nucleic acid preparations prior to downstream analysis (e.g., PCR setup, electrophoresis buffer chilling).
• Calibration reference baths: serving as a stable thermal sink for thermometer or RTD verification within accredited metrology workflows (when used with NIST-traceable secondary standards).
• Materials testing: thermal cycling support for polymer characterization, crystallinity studies, or low-temperature rheology where external fluid coupling is required.

FAQ

What coolant fluids are recommended for operation at −80 °C?
Ethylene glycol–water mixtures (e.g., 60:40 v/v) or specialized low-temperature silicone oils rated for ≤−85 °C service are appropriate. Avoid pure water below 0 °C or alcohols with high vapor pressure.
Can this unit be integrated into a GMP manufacturing environment?
Yes—as a utility-grade support device—but qualification (IQ/OQ/PQ) must be performed by the end user. It lacks built-in 21 CFR Part 11 compliance features; electronic records require external validation.
Is remote monitoring possible without third-party hardware?
No. The unit has no Ethernet, USB, or RS-232 interface. Analog voltage/current outputs enable connection to PLCs or DAQ systems for basic telemetry.
What maintenance intervals are recommended for the Danfoss compressor?
Annual inspection of refrigerant charge, condenser coil cleanliness, and electrical connections is advised. Compressor oil life exceeds 15,000 operating hours under nominal load conditions.
Does the circulation pump support continuous operation at maximum flow and pressure?
Yes—the sealed, brushless motor is rated for indefinite duty at 20 L/min and 2 MPa, provided inlet fluid temperature remains within −80 to 40 °C and particulate contamination is minimized via inline filtration.