Great Wall DL-400 Circulating Chillers
| Brand | Great Wall |
|---|---|
| Origin | Henan, China |
| Manufacturer Type | Original Equipment Manufacturer (OEM) |
| Country of Origin | China |
| Model | DL-400 |
| Pricing | Available Upon Request |
Overview
The Great Wall DL-400 Circulating Chiller is a precision-engineered temperature control system designed for laboratory-scale applications requiring stable, continuous low-temperature circulation. It operates on the principle of vapor-compression refrigeration, integrating a hermetic compressor, copper-aluminum finned condenser, expansion valve, and evaporator coil to deliver consistent thermal regulation across external process loops. Unlike immersion-style cooling baths, the DL-400 employs a closed-loop circulation architecture—pumping chilled fluid (typically water or water-glycol mixtures) through external equipment such as rotary evaporators, spectrophotometer jackets, NMR probe coolers, or reaction calorimeters. Its design prioritizes thermal stability (±0.3 °C typical at setpoint), low-noise operation (<58 dB(A)), and long-term reliability under intermittent or continuous duty cycles. The unit is intended for indoor laboratory environments compliant with IEC 61010-1 safety standards for electrical equipment used in measurement, control, and laboratory use.
Key Features
- Stainless steel reservoir (capacity: 12 L) with integrated level sensor and overfill protection
- Dual-stage temperature control: PID-regulated electronic thermostat with digital display (range: –20 °C to +40 °C; resolution: 0.1 °C)
- High-efficiency centrifugal circulation pump (max flow rate: 20 L/min; max head: 6 m; pressure rating: 0.3 MPa)
- Refrigeration system based on R134a refrigerant (ODP = 0, GWP = 1430), compliant with current EU F-Gas Regulation Annex I thresholds for lab-scale chillers
- Intelligent safety suite including compressor high-pressure cut-off, low-flow alarm, dry-run protection, and over-temperature shutdown
- Front-panel USB port for firmware updates and diagnostic logging (no cloud connectivity)
Sample Compatibility & Compliance
The DL-400 supports compatibility with standard laboratory fluid circuits using 1/4″–3/8″ compression or push-to-connect fittings (ISO 8434-1). It accommodates aqueous solutions, 30% ethylene glycol/water blends, and other non-corrosive heat-transfer fluids with pH 5.5–8.5 and viscosity <20 cP at operating temperature. While not certified to UL 61010-1 or CE marking for North American or EU commercial distribution, the unit conforms to GB/T 29588–2013 (Chinese national standard for laboratory refrigerated circulators) and meets basic electromagnetic compatibility per GB/T 18268.1–2010 (equivalent to IEC 61326-1 Class A). It is suitable for GLP-aligned environments where instrument qualification (IQ/OQ) is performed by end users per internal SOPs.
Software & Data Management
The DL-400 operates via embedded firmware without proprietary PC software. All operational parameters—including setpoint, actual bath temperature, pump speed (%), compressor status, and alarm history—are accessible through the 4.3″ TFT LCD interface with touch-sensitive navigation. Real-time data logging is stored locally (up to 30 days of 1-minute interval records) and exportable via USB flash drive in CSV format. Audit trail functionality includes timestamped entries for setpoint changes, alarm events, and manual overrides—supporting traceability requirements under ISO/IEC 17025 Clause 7.7 and FDA 21 CFR Part 11 when deployed within validated laboratory workflows (user-configured electronic signatures required).
Applications
- Condenser cooling for rotary evaporation systems (e.g., Büchi R-300, IKA RV 10) to maintain solvent recovery efficiency below 35 °C
- Temperature stabilization of UV-Vis spectrophotometer sample compartments and detector housings during kinetic assays
- Heat removal from laser sources, CCD detectors, or X-ray diffraction goniometers requiring thermal drift suppression
- Controlled exothermic reaction monitoring in jacketed glass reactors (≤5 L volume) using external PTFE-coated tubing
- Support of HPLC column ovens and autosampler chill trays where ambient fluctuations exceed ±2 °C
FAQ
What is the minimum ambient operating temperature for the DL-400?
The unit is rated for ambient operation between +10 °C and +35 °C. Below 10 °C, compressor oil viscosity increases risk of startup failure; above 35 °C, condenser efficiency degrades significantly.
Can the DL-400 be used with flammable solvents in the external loop?
No. The chiller is not explosion-proof and must only circulate non-flammable, non-toxic heat-transfer media. Solvent vapors must never enter the reservoir or pump head.
Is remote monitoring or Ethernet connectivity supported?
No. The DL-400 lacks network interfaces. Remote access requires integration via external PLC or third-party SCADA systems using analog 4–20 mA output (optional accessory).
Does the unit include a filtration system for the circulating fluid?
It features a 50 µm stainless steel mesh inlet strainer but does not include active particulate or microbial filtration. Users must implement inline filters (e.g., 5 µm polypropylene) if particulates or biological growth are concerns.
What maintenance intervals are recommended?
Compressor oil inspection every 24 months; condenser coil cleaning every 6 months in dusty environments; reservoir disinfection quarterly when using water-based fluids.
