Great Wall ZTM-20-200-40 Closed-Loop Refrigerated & Heated Circulator

Overview

The Great Wall ZTM-20-200-40 is an integrated closed-loop refrigerated and heated circulator engineered for precise, dynamic temperature control across demanding laboratory and pilot-scale process applications. Unlike open-bath chillers or single-function heating/cooling units, the ZTM series employs a tri-system architecture—comprising independent refrigeration, electric heating, and pre-cooling circuits—that enables seamless bidirectional thermal modulation without system downtime. It operates on the principle of forced convection circulation of thermally stable heat transfer fluid (e.g., silicone oil or specialized synthetic bath fluids) through externally connected equipment such as jacketed reactors, calorimeters, distillation columns, or environmental test chambers. Its fully sealed loop minimizes fluid degradation, oxidation at elevated temperatures (>150 °C), and moisture ingress or condensation at sub-zero operation (<0 °C), thereby extending service life and ensuring long-term calibration integrity. Designed for continuous duty under ambient conditions of 5–35 °C and ≤70% RH, the unit complies with IEC 61000-6-3 (EMC) and IEC 61000-6-2 (immunity) standards and meets mechanical safety requirements per ISO 12100.

Key Features

• Tri-system thermal architecture: Independent refrigeration, heating, and pre-cooling circuits allow uninterrupted operation during rapid ramping or hold cycles.
• High-precision temperature control: Advanced fuzzy-PID algorithm delivers ±0.5 °C stability across the full -40 °C to 200 °C range; programmable setpoint resolution of 0.1 °C.
• Robust circulation performance: Magnetically coupled centrifugal pump ensures zero leakage across the entire operating range; 90 L/min flow at 1.5 bar maximum head pressure.
• Intelligent user interface: 5.7″ color TFT touchscreen with dual-language support (English/Chinese), real-time graphical trend display, and intuitive navigation for both fixed-value and multi-segment program control.
• Comprehensive safety architecture: Dual-stage overtemperature protection (sensor + mechanical thermostat), ground-fault interruption, overcurrent cutoff, pressure-sensing interlock, and real-time reservoir level monitoring with audible/visual alarm.
• Optimized thermal efficiency: Brazed plate heat exchanger with high surface-area-to-volume ratio maximizes heat transfer while minimizing footprint; R404A refrigerant selected for broad operational envelope and compatibility with high-temperature heat transfer media.

Sample Compatibility & Compliance

The ZTM-20-200-40 supports a wide range of heat transfer fluids—including silicone oils (e.g., Dow Corning 200 Fluid), polyalphaolefins (PAOs), and glycol-water mixtures—within its sealed loop, provided viscosity remains within 1–500 cSt at operating temperature. It interfaces with standard R2¾ threaded external ports (ISO 228-1) for connection to jacketed vessels, calorimeters, or custom thermal test rigs. The unit is CE-marked and conforms to EN 61000-6-2 (electromagnetic immunity) and EN 61000-6-3 (emission). While not certified to UL/CSA or ATEX by default, it may be configured for GMP-aligned environments when paired with validated SOPs and audit-ready documentation packages. For pharmaceutical applications, the system supports 21 CFR Part 11-compliant data logging when integrated with third-party software platforms via its Modbus RTU interface.

Software & Data Management

The onboard controller stores up to 120 user-defined programs, each comprising up to 100 individual segments with ramp/halt/soak parameters. All setpoints, actual temperatures, flow status, and alarm logs are timestamped and viewable on-screen. Optional RS485/Modbus RTU communication enables integration into SCADA or LIMS environments for centralized monitoring, remote parameter adjustment, and automated report generation. When used with compliant external software, the system supports electronic signatures, audit trails, and data export in CSV format—facilitating GLP/GMP traceability requirements. No proprietary cloud platform is required; local Ethernet or serial connectivity suffices for secure, firewall-compatible deployment.

Applications

• Temperature control of double- and triple-jacketed glass or stainless-steel reactors in API synthesis, polymerization, and crystallization processes.
• Thermal conditioning of analytical instrumentation—including HPLC column ovens, viscometers, and DSC sample stages—requiring stable, noise-free thermal environments.
• Material testing under controlled thermal cycling: tensile testing at sub-zero temperatures, thermal shock simulation, and coefficient-of-thermal-expansion (CTE) measurement.
• Process validation studies requiring precise ramp-and-soak profiles per ASTM E2554 or ISO 17025 guidelines.
• Automotive component thermal testing: battery module thermal management validation, brake fluid boiling point assessment, and HVAC component endurance evaluation.
• Vacuum chamber temperature stabilization for thin-film deposition or cryo-pumping applications where condensation must be avoided.

FAQ

What types of heat transfer fluids are compatible with the ZTM-20-200-40?

Silicone oils (e.g., DC 200 series), polyalphaolefins (PAOs), and inhibited ethylene glycol/water blends (≤60% glycol) are suitable. Fluids must remain pumpable between -40 °C and 200 °C and exhibit thermal stability >200 °C.

Can the unit operate unattended overnight?

Yes—programmable scheduling, delay-start function, and comprehensive safety interlocks enable safe extended operation. However, periodic visual inspection of fluid level and ambient ventilation is recommended per preventive maintenance protocols.

Is the ZTM-20-200-40 suitable for use in cleanrooms or ISO Class 5 environments?

The unit itself is not classified for cleanroom use due to its air-cooled condenser design; however, it may be installed in adjacent utility spaces with remote circulation lines routed into clean areas via sealed conduits.

Does the system support external temperature feedback from the process load?

Yes—the controller accepts optional external PT100 input for cascade control, enabling direct regulation based on reactor jacket or sample temperature rather than bath temperature alone.

What is the expected service interval for refrigerant recharge or compressor maintenance?

Under normal operation and proper fluid maintenance, the hermetic compressor requires no scheduled refrigerant recharge. Annual inspection of condenser coil cleanliness, pump seal integrity, and electrical connections is advised per manufacturer’s maintenance schedule.