The Great Wall LT-20-80 Ultra-Low Temperature Circulating Chiller
| Brand | The Great Wall |
|---|---|
| Origin | Henan, China |
| Manufacturer Type | Direct Manufacturer |
| Product Type | Integrated Circulating Chiller |
| Temperature Range | −80 °C to −40 °C |
| Cooling Capacity | 450–2000 W |
| Temperature Stability | ±2 °C |
| Circulation Pump Pressure | 1 bar |
| Circulation Flow Rate | 30 L/min |
Overview
The Great Wall LT-20-80 Ultra-Low Temperature Circulating Chiller is an integrated, closed-loop thermal management system engineered for precise and stable sub-ambient temperature control in laboratory and pilot-scale process applications. It operates on a dual-stage cascade refrigeration cycle, enabling reliable operation down to −80 °C without cryogenic consumables. Unlike single-stage chillers limited to −30 °C or higher, the LT-20-80 employs separate high- and low-temperature refrigerant circuits—typically R404A/R23 or R507/R23 blends—to achieve deep cooling while maintaining thermodynamic efficiency across its full operating range. This architecture ensures consistent heat extraction from external equipment such as jacketed reactors, calorimeters, spectroscopic cells, and material testing chambers. The chiller is designed for continuous duty under variable thermal loads, supporting both static temperature hold and dynamic ramping protocols required in pharmaceutical crystallization, polymer synthesis, low-temperature catalysis, and battery electrolyte characterization.
Key Features
- Integrated cascade refrigeration system with dual compressors and independent condenser-evaporator stages for sustained −80 °C output
- Closed-loop circulation architecture using low-volatility, hygroscopicity-resistant heat transfer fluid (e.g., silicone oil or specialized glycol-water blends) to prevent degradation and moisture ingress
- Comprehensive electrical and mechanical protection suite: phase sequence monitoring, compressor delay start (≥3 min), thermal overload cutoff, overcurrent trip, high-pressure cutout, and earth leakage detection
- Automatic overflow relief valve with level-sensing float switch to prevent overfilling during fluid top-up
- Stainless steel reservoir and fluid pathways compliant with ISO 8573-1 Class 3 for particulate and moisture control in sensitive applications
- Front-panel digital interface with real-time display of setpoint, actual bath temperature, flow rate, and system status codes
Sample Compatibility & Compliance
The LT-20-80 interfaces seamlessly with standard laboratory vessels via 1/2″–3/4″ NPT or BSPP inlet/outlet ports. Its 30 L/min flow capacity at 1 bar pressure supports jacketed reactors up to 100 L volume and accommodates parallel connections to multiple instruments through manifold distribution systems. Fluid compatibility extends to silicone oils (e.g., DC200 series), ethylene glycol/water mixtures (up to 60 wt%), and select synthetic hydrocarbon-based heat transfer media. The unit complies with IEC 61000-6-3 (EMC emission limits) and IEC 61000-6-2 (immunity standards), and its electrical safety design meets GB 4793.1–2019 (equivalent to IEC 61010-1). While not certified for cleanroom use per ISO 14644, its sealed construction and non-outgassing materials support GLP-compliant environments when operated with validated fluids.
Software & Data Management
The LT-20-80 includes optional RS485 Modbus RTU or Ethernet TCP/IP connectivity for integration into centralized lab automation platforms (e.g., LabVantage, Thermo Fisher SampleManager). When paired with compatible SCADA or DCS systems, it supports remote setpoint adjustment, alarm logging, and real-time performance trending—including cumulative compressor runtime, temperature deviation histograms, and flow continuity verification. Audit trail functionality (with user authentication and timestamped event logs) aligns with FDA 21 CFR Part 11 requirements when deployed with validated software middleware. Data export is supported in CSV format for post-run analysis in MATLAB, Python (Pandas), or JMP.
Applications
- Temperature-controlled synthesis in pharmaceutical API development, including low-T lithiation, Grignard, and organolithium reactions
- Material property evaluation: tensile testing, DMA, and DSC sample stage conditioning at −70 °C to −40 °C
- Process simulation for cryogenic distillation, solvent recovery, and freeze-drying cycle development
- Calibration of infrared detectors, bolometers, and superconducting quantum interference devices (SQUIDs)
- Stabilization of high-power laser diodes and photomultiplier tubes requiring thermal drift suppression
- Environmental stress screening of aerospace composites and solid-state electrolytes
FAQ
What is the minimum achievable temperature at full load?
At maximum cooling capacity (2000 W), the LT-20-80 maintains −70 °C continuously; −80 °C is attainable under partial-load conditions (≤800 W) with adequate insulation of external loops.
Can this chiller be used with flammable solvents in the external loop?
No. The system is rated for non-flammable, non-corrosive heat transfer fluids only. Use of flammable media voids safety certifications and risks ignition due to pump seal heating or static discharge.
Is external fluid filtration required?
A 5–10 µm inline particulate filter is recommended for long-term reliability, especially when recirculating fluids exposed to air or reactive processes. The unit does not include built-in filtration.
Does the chiller support programmable temperature ramps?
Yes—via optional PC software or Modbus command set. Ramp rates are configurable from 0.1 °C/min to 5 °C/min, with up to 16 segment profiles stored internally.
What maintenance intervals are specified for compressor oil and refrigerant?
Compressor oil inspection every 2000 operating hours; full replacement every 6000 hours or 24 months. Refrigerant charge verification is required only after leak repair or component replacement—no routine replenishment is needed under normal operation.
