DLSB-6/20 Cryogenic Constant Temperature Circulator – Yarong (Shanghai)

Overview

The DLSB-6/20 Cryogenic Constant Temperature Circulator is a compact, self-contained laboratory circulation system engineered for precise thermal management of external equipment requiring stable low-temperature operation. Designed around a closed-loop refrigeration architecture with integrated immersion bath and high-efficiency centrifugal pump, it delivers consistent coolant flow at controlled temperatures between −20 °C and +25 °C. Its core function is to maintain thermal equilibrium in externally connected apparatus—such as rotary evaporators, spectrophotometer cells, condensers, or reaction jackets—by circulating chilled ethylene glycol/water or ethanol/water mixtures through user-defined external pathways. Unlike passive cold traps or dry ice baths, this unit provides active, programmable temperature regulation with real-time feedback control, enabling reproducible experimental conditions essential for kinetic studies, crystallization protocols, and low-temperature synthesis.

Key Features

• Integrated 6-liter stainless-steel bath with corrosion-resistant interior and transparent lid for visual monitoring of fluid level and circulation status.
• High-reliability hermetic compressor paired with copper-aluminum finned condenser for sustained operation within the −20 °C to +25 °C range.
• Digital PID temperature controller with LED display, offering intuitive setpoint adjustment and real-time bath temperature readout.
• Adjustable flow rate (up to 15 L/min) via calibrated outlet valve; pressure-rated output port compatible with standard 10–16 mm ID tubing.
• Over-temperature, low-level, and over-current protection circuits ensure operational safety and equipment longevity.
• Robust structural design with reinforced base, non-slip rubber feet, and front-accessible drain valve for maintenance and fluid replacement.

Sample Compatibility & Compliance

The DLSB-6/20 circulator is compatible with common low-freezing-point heat transfer fluids—including 30–50% aqueous ethylene glycol, methanol, or ethanol solutions—selected based on required minimum operating temperature and chemical compatibility with connected systems. It does not contact samples directly; rather, it serves as an auxiliary thermal management module compliant with general laboratory infrastructure standards (IEC 61010-1:2010 for electrical safety). While not certified to ISO/IEC 17025 or GLP as a standalone analytical instrument, its stable thermal output supports method validation workflows where temperature consistency is critical—for example, in USP compounding environments or ASTM E2877-compliant viscosity calibration setups requiring bath-controlled viscometers.

Software & Data Management

This model operates via embedded digital controls without proprietary software or PC connectivity. All parameters—including setpoint, actual bath temperature, and system status—are displayed locally on a high-contrast LED interface. No data logging, remote access, or audit trail functionality is included. For laboratories requiring traceable temperature records, integration with third-party data acquisition systems (e.g., LabVIEW or Modbus-enabled PLCs) may be achieved via optional analog 0–5 V or 4–20 mA output modules (sold separately). The absence of FDA 21 CFR Part 11-compliant electronic records means manual logbook entries remain the default for GxP-aligned documentation.

Applications

• Temperature stabilization of rotary evaporator condensers during solvent removal under reduced pressure.
• Cooling jacket support for exothermic organic reactions conducted in glass reactors or jacketed flasks.
• Thermal conditioning of UV-Vis cuvette holders, fluorescence spectrometer sample compartments, or FTIR ATR accessories.
• Providing consistent cold source for cryo-microscopy sample stages or electrophoresis buffer tanks.
• Calibration support for thermocouples, RTDs, and digital thermometers across sub-zero reference points.
• Pre-cooling of mobile phase reservoirs in preparative HPLC systems to reduce solvent degassing and column thermal drift.

FAQ

What is the recommended heat transfer fluid for operation at −20 °C?
A 45% (v/v) ethylene glycol–water mixture typically achieves a freezing point below −25 °C and maintains suitable viscosity for pump circulation. Methanol-based fluids are discouraged due to volatility and material compatibility risks.
Can this unit be used for heating-only applications?
No—the DLSB-6/20 is refrigeration-only; it lacks resistive heating elements and cannot elevate bath temperature above ambient without external heat input.
Is the pump flow rate adjustable during operation?
Yes—flow is manually regulated via a calibrated needle valve on the discharge port, allowing optimization for pressure drop across external loops while maintaining thermal stability.
Does the unit include insulation for the external tubing connections?
No—thermal insulation of external lines is the user’s responsibility to minimize ambient heat ingress, especially when operating near −20 °C.
What maintenance intervals are recommended for long-term reliability?
Compressor oil and refrigerant integrity should be verified annually; bath fluid should be replaced every 6–12 months depending on usage frequency and contamination risk. Filter cleaning is advised after each fluid change.