Scientz GH-30A High-Precision Circulating Bath (Heating & Cooling)
| Brand | Scientz |
|---|---|
| Origin | Zhejiang, China |
| Manufacturer Type | Direct Manufacturer |
| Product Category | Domestic |
| Model | GH-30A |
| Instrument Type | Circulating Temperature Bath |
| Circulation Mode | Internal & External |
| Temperature Control | Dual-mode (Heating & Refrigeration) |
| Bath Dimensions (L×W×H) | 400 × 330 × 230 mm |
| Temperature Range | +5 °C to +200 °C |
| Temperature Stability | ±0.005 °C to ±0.02 °C |
Overview
The Scientz GH-30A is a high-precision, dual-mode circulating bath engineered for laboratory-grade thermal control in research, calibration, and quality assurance applications. Utilizing a closed-loop refrigeration system with environmentally compliant refrigerant (R134a or equivalent), the GH-30A delivers stable, uniform temperature fields across its 30 L working volume (400 × 330 × 230 mm internal chamber). Its core architecture integrates a microprocessor-based PID controller with adaptive tuning algorithms, enabling dynamic compensation for load variations, ambient fluctuations, and heat exchange dynamics. Unlike basic immersion baths, the GH-30A supports both internal circulation (for homogeneous bath temperature) and external circulation (for remote temperature conditioning of analytical instruments, reactors, or sensor test fixtures). It functions as a self-contained thermal source/sink—capable of precise heating up to +200 °C and active cooling down to +5 °C—making it suitable for calibration traceability workflows, viscosity standardization, and thermal validation protocols requiring NIST-traceable stability.
Key Features
- Microprocessor-controlled PID algorithm with auto-tuning capability for optimal response across full temperature range
- Dual-circulation mode: switchable internal recirculation (for bath homogeneity) and external pump-driven circulation (max. flow rate adjustable up to 15 L/min, pressure head ≤ 0.2 MPa)
- High-stability thermal performance: ±0.005 °C at setpoints near ambient; ±0.02 °C across extended ranges (e.g., +150 °C), verified per ISO/IEC 17025-compliant validation procedures
- Power-loss recovery function: retains all user-defined parameters (setpoint, circulation mode, timer, pump speed) after interruption; configurable auto-restart or standby-on-power-up behavior
- Programmable digital timer: 1-minute to 99-hour 59-minute operation scheduling with automatic shutdown upon completion
- Stainless steel 304 bath tank with corrosion-resistant insulation and integrated level sensor to prevent dry-run operation
Sample Compatibility & Compliance
The GH-30A accommodates standard laboratory glassware (up to Ø200 mm diameter vessels), probe-type sensors (RTDs, thermistors, PRTs), and calibration standards including mercury-in-glass thermometers, platinum resistance thermometers (PRTs), and infrared reference sources. Its fluid compatibility extends to water, silicone oil (up to 200 °C), and low-viscosity heat-transfer fluids meeting ASTM D4689 specifications. The unit complies with IEC 61010-1:2010 for electrical safety in laboratory equipment and meets CE marking requirements under the EU Low Voltage and EMC Directives. While not certified for Class I Div 1 hazardous locations, it is routinely deployed in GLP-compliant calibration labs where temperature uniformity and stability data are recorded for audit trails per ISO/IEC 17025 Clause 6.4.2.
Software & Data Management
The GH-30A operates autonomously via its front-panel interface but supports optional RS485/Modbus RTU communication for integration into centralized lab monitoring systems (e.g., LabVantage, Thermo Fisher SampleManager). Logged temperature data—including real-time setpoint, actual bath temperature, external loop outlet temperature (when enabled), and error codes—is timestamped with millisecond resolution and exportable via USB flash drive in CSV format. Audit trail functionality includes operator ID tagging (via optional RFID badge reader module), change history of setpoints and modes, and tamper-evident logging aligned with FDA 21 CFR Part 11 principles for electronic records in regulated environments.
Applications
- Primary and secondary thermometer calibration against reference standards per ASTM E77 and ISO 17025
- Thermal validation of DSC, TGA, and rheometer temperature sensors
- Stabilization of optical benches, interferometers, and laser diodes requiring sub-0.01 °C thermal drift control
- Conditioning of reference materials for viscometry (ASTM D445), density (ASTM D1298), and thermal conductivity testing
- Temperature-controlled sample preparation in pharmaceutical QC (USP , EP 2.2.43)
- Supporting accelerated aging studies in polymer and battery material research where precise thermal ramping and hold profiles are critical
FAQ
What is the maximum external circulation pressure the GH-30A can sustain?
The built-in circulation pump delivers a maximum head pressure of 0.2 MPa (2 bar) at zero flow; pressure decreases linearly with increasing flow rate, reaching ~0.08 MPa at 15 L/min.
Can the GH-30A maintain ±0.005 °C stability at 180 °C?
Stability of ±0.005 °C is achievable within ±5 °C of ambient temperature; at elevated setpoints (e.g., 180 °C), typical stability is ±0.02 °C due to increased thermal gradient effects and convective losses.
Is the bath tank compatible with silicone oil for operation above 100 °C?
Yes—the stainless steel 304 tank and internal seals are rated for continuous use with methylphenyl silicone oils meeting Dow Corning PMX-200 or equivalent specifications up to 200 °C.
Does the GH-30A support external PT100 input for cascade control?
No—external sensor feedback is not supported; temperature regulation relies solely on the integrated high-accuracy Pt100 sensor located in the bath sump.
How is temperature uniformity validated across the bath volume?
Uniformity is specified as ≤ ±0.03 °C (peak-to-peak) at 100 mm depth, measured using a calibrated 9-point probe array per ISO 17025 Annex A.3 guidelines for thermal equipment verification.
