The Great Wall ZTM-20-200-40Ex Explosion-Proof Integrated Heating and Cooling Circulator

Overview

The Great Wall ZTM-20-200-40Ex is an explosion-proof, fully integrated heating and cooling circulator engineered for precise thermal management in hazardous environments. It operates on a closed-loop circulation principle, delivering controlled thermal energy—either heat or cold—to external process equipment via a thermally stable heat-transfer fluid (e.g., silicone oil or specialized synthetic bath fluids). Unlike open-bath systems, its hermetically sealed design prevents fluid evaporation, oxidation, and moisture absorption from ambient air—significantly extending fluid service life and maintaining consistent thermal performance across extended operational cycles. The unit integrates a high-efficiency scroll compressor, explosion-proof electric heater (certified per IEC 60079-1 and GB 3836.1), intrinsically safe circulation pump, and ATEX/China Ex-certified control cabinet. It is designed for continuous-duty operation under ambient conditions of 5–35 °C and ≤70% relative humidity, with IP20 ingress protection and Pollution Degree 2 compliance—suitable for Zone 1/21 classified areas when installed per local hazardous location regulations.

Key Features

• Explosion-proof certified components throughout: heater, pump, electrical enclosure, and terminal wiring—fully compliant with GB 3836 series and compatible with international Ex standards (IEC 60079) for gas and dust environments.
• Closed-loop circulation architecture minimizes fluid degradation; built-in liquid level sensor enables real-time monitoring and low-level alarm activation.
• Multi-layer safety system: independent overtemperature cutoff, high-pressure refrigerant shutdown, earth-leakage detection, compressor delayed-start logic, thermal overload protection, overcurrent tripping, and phase-sequence monitoring.
• Precise temperature control: ±0.5 °C stability across full range (−40 °C to +200 °C); enhanced stability of ±0.1 °C achievable within select sub-ranges via optimized PID tuning and dual-sensor feedback (outlet, return, or process load temperature).
• Flexible control modes: constant setpoint, ramp-hold programs, slope-controlled heating/cooling, or custom multi-step profiles—configurable via intuitive 7-inch color TFT touchscreen interface with 0.01 °C display and setting resolution.
• Advanced thermal management algorithms including ΔT (temperature differential) control to prevent overshoot at the connected reactor or test chamber, especially critical during exothermic/endothermic transitions.
• Standard digital interfaces: isolated RS485 (Modbus RTU protocol) and USB 2.0 for data logging, remote supervision, and integration into centralized SCADA or LIMS platforms.

Sample Compatibility & Compliance

The ZTM-20-200-40Ex is compatible with a wide range of heat-transfer media—including silicone oils (e.g., DC200 series), polyalphaolefins (PAOs), and specialized low-volatility synthetic fluids—subject to flash point and viscosity compatibility within the specified temperature envelope. Its closed system supports fluid volumes up to 7 L and accommodates external loops with standard 3/4″ NPT (R23/4) fittings and included 2.6 m insulated stainless-steel hose. From a regulatory standpoint, the device meets GB/T 19001 (ISO 9001) quality management requirements and incorporates design elements aligned with GLP and GMP environmental control expectations. While not inherently 21 CFR Part 11 compliant, audit-trail-capable data export (via USB) and user-accessible calibration logs support validation documentation for regulated pharmaceutical and chemical manufacturing processes.

Software & Data Management

The embedded controller firmware provides real-time graphical visualization of temperature trajectories—including simultaneous plotting of setpoint, actual outlet temperature, return temperature, and internal refrigerant pressure. All operational events (alarms, mode changes, parameter modifications) are time-stamped and stored in non-volatile memory for up to 30 days. Data can be exported in CSV format via USB stick for post-processing in MATLAB, Excel, or statistical analysis tools. RS485 communication allows bidirectional integration with programmable logic controllers (PLCs) or laboratory automation systems using standard Modbus register mapping—enabling synchronized start/stop commands, setpoint updates, and status polling without manual intervention.

Applications

• Temperature control of jacketed glass reactors and pilot-scale stainless-steel vessels in API synthesis and fine chemical manufacturing.
• Thermal cycling and aging tests for lithium-ion battery modules and EV traction battery packs under simulated charge/discharge thermal loads.
• Material characterization workflows requiring precise thermal ramping: DSC sample prep, rheological testing of polymer melts, and curing kinetics studies of composites.
• Stabilization of optical benches, vacuum chambers, and semiconductor wafer handling stages where ambient thermal drift must remain below ±0.2 °C.
• In-process simulation of seasonal or operational thermal transients in automotive component testing (e.g., power electronics, ADAS sensors).

FAQ

Is the ZTM-20-200-40Ex certified for use in Class I, Division 1 hazardous locations?

No—it is certified under Chinese GB 3836 standards for Ex d IIB T4 Gb and Ex tb IIIC T135°C Db classifications, suitable for Zone 1 (gas) and Zone 21 (dust) per IEC 60079. Site-specific classification verification and installation by qualified personnel are mandatory.
What refrigerant does the unit use, and is it compliant with current environmental regulations?

It employs R404A, a zeotropic HFC blend with GWP of 3922. While permitted for existing equipment under current EU F-Gas Regulation exemptions, users planning long-term deployment should consider future phase-down schedules and consult local environmental authorities regarding alternatives.
Can the unit operate unattended for extended periods, such as overnight or weekend runs?

Yes—designed for continuous 24/7 operation with redundant safety interlocks, automatic fault recovery logic, and configurable email/SMS alerts via optional gateway modules (not included standard).
Does the system support external temperature feedback from the reactor jacket or process vessel?

Yes—the controller accepts analog input (4–20 mA or 0–10 V) from third-party PT100 or thermocouple transmitters, enabling true cascade control where the circulator modulates output based on actual process temperature rather than its own outlet reading.
What maintenance intervals are recommended for optimal long-term reliability?

Compressor oil and refrigerant filter replacement every 24 months; annual inspection of electrical connections, grounding integrity, and explosion-proof housing fasteners; biannual verification of safety relay response times and calibration of temperature sensors against NIST-traceable references.