The Great Wall DL30-700 Circulating Chiller

Overview

The Great Wall DL30-700 is an integrated air-cooled circulating chiller engineered for precise, stable low-temperature thermal management in demanding laboratory and pilot-scale applications. It operates on a closed-loop refrigeration cycle using R410A—a zero-ozone-depletion-potential (ODP), low-global-warming-potential (GWP) refrigerant—paired with a high-efficiency scroll compressor and optimized condenser airflow design. The unit delivers continuous cooling capacity ranging from 300 W at −25 °C to 1750 W at 0 °C, enabling reliable temperature control across exothermic reaction monitoring, rotary evaporation condensation, material property testing under thermal stress, and semiconductor process equipment stabilization. Its sealed 304 stainless steel reservoir (17 L) minimizes fluid oxidation and moisture absorption, ensuring long-term thermal fluid integrity and consistent heat transfer performance over extended operation cycles.

Key Features

• Wide operating range: Stable output temperature control from −30 °C to +5 °C with ±2 °C stability—validated under ISO 17025-aligned environmental conditions (25 °C ambient, ≤70% RH).
• Robust safety architecture: Integrated multi-layer protection including compressor delay start (prevents voltage surge damage), high-pressure cut-off, thermal overload relay, overcurrent circuit interruption, and real-time liquid level monitoring via calibrated float sensor.
• Precision fluid handling: 20 L/min flow rate at 0.4 bar head pressure, delivered by a corrosion-resistant centrifugal pump with 100 W brushless motor—optimized for low pulsation and minimal cavitation risk in external loops up to 15 m total equivalent length.
• Industrial-grade construction: 304 stainless steel reservoir, reinforced powder-coated steel chassis, and IP20-rated electrical enclosure compliant with IEC 61000-6-3 (EMC immunity) and IEC 61000-6-4 (EMC emission) standards.
• Operational transparency: Dual-display digital interface showing setpoint, actual outlet temperature (Pt100-sensed), reservoir level, and system fault codes—supporting intuitive diagnostics without external software.

Sample Compatibility & Compliance

The DL30-700 is compatible with common heat-transfer fluids including water, 30% ethylene glycol/water mixtures, and silicone-based synthetic oils (viscosity < 50 cSt at 20 °C). Its closed-loop design prevents volatile loss and atmospheric moisture ingress—critical for maintaining fluid specification compliance per ASTM D1122 and ISO 6743-20. The unit meets CE marking requirements under the EU Machinery Directive 2006/42/EC and Low Voltage Directive 2014/35/EU. Electrical safety certification includes EN 61010-1:2019 for laboratory equipment, while refrigerant handling adheres to EN 378-1:2016 for hermetic systems. No hazardous substance declarations (RoHS 2011/65/EU) or REACH SVHC screening reports are required for standard configuration.

Software & Data Management

The DL30-700 operates as a standalone instrument with no embedded firmware-based data logging or network connectivity. All operational parameters—including temperature setpoint, real-time outlet reading, reservoir level status, and active fault flags—are displayed locally via a high-contrast LED interface. For integration into GLP/GMP-regulated environments, optional analog 4–20 mA output (0–10 V available on request) enables connection to external SCADA or LIMS platforms for audit-trail-capable temperature recording. While not natively 21 CFR Part 11 compliant, the unit supports third-party validation protocols when paired with qualified data acquisition hardware meeting ALCOA+ principles (Attributable, Legible, Contemporaneous, Original, Accurate, Complete, Consistent, Enduring, Available).

Applications

• Temperature control of jacketed glass reactors (1–50 L) during catalytic hydrogenation, Grignard synthesis, or cryogenic lithiation.
• Cooling condenser coils on rotary evaporators (up to 50 L capacity) processing heat-sensitive solvents such as THF, diethyl ether, or chloroform.
• Thermal conditioning of tensile testers, DSC sample stages, and DMA fixtures during polymer crystallinity or glass transition analysis.
• Stabilization of laser diodes, CCD detectors, and RF amplifiers in analytical instrumentation requiring sub-ambient thermal anchoring.
• Process simulation in pharmaceutical development labs—e.g., simulating cold-chain storage conditions for lyophilized formulations or accelerated stability chambers.

FAQ

What is the minimum ambient temperature at which the DL30-700 can operate reliably?
The unit is rated for continuous operation between 5 °C and 35 °C ambient temperature. Below 5 °C, compressor oil viscosity increases and refrigerant return may be impaired; supplemental heating of the compressor compartment is not supported.
Can the chiller be used with flammable heat-transfer fluids?
No. Only non-flammable, chemically stable fluids meeting ASTM D3487 Type I or ISO 6743-20 Class H classification are approved. Use of hydrocarbon-based oils or alcohols voids warranty and violates EN 61010-1 safety certification.
Is remote monitoring or control possible?
The base model lacks Ethernet, RS485, or Wi-Fi interfaces. Analog output (4–20 mA) is available as a factory-installed option for external PID integration or PLC-based cascade control.
What maintenance intervals are recommended?
Compressor oil and refrigerant charge require no scheduled servicing within first 5 years or 10,000 operational hours. Annual inspection of air filter, condenser coil cleanliness, and reservoir fluid pH (target 6.5–8.5) is advised per ISO 55001 asset management guidelines.
Does the unit support dual-temperature zone operation?
No. The DL30-700 provides single-loop temperature control only. For independent dual-zone applications, consider the Great Wall DLS series with parallel refrigeration circuits and separate outlet manifolds.