Grant HED Series High-Temperature Circulating Bath

Overview

The Grant HED Series High-Temperature Circulating Bath is an engineered thermal management system designed for precision temperature control in demanding laboratory and industrial applications requiring sustained operation between 50 °C and 260 °C. Based on a robust Couette-flow circulation architecture and integrated with Grant’s proprietary electronic temperature regulation system, the HED bath delivers exceptional thermal stability (±0.25 °C at 150 °C, per DIN 58966) and spatial uniformity (±0.2 °C across the working zone). Its dual-chamber design—comprising a thermally insulated stainless steel reservoir and a high-emissivity enamel-coated outer housing—ensures structural integrity under prolonged thermal stress while minimizing external surface temperatures. The unit operates via resistive heating combined with high-torque magnetic stirring and optimized fluid dynamics to prevent localized hot spots and thermal degradation of silicone oil or other compatible high-boiling-point heat transfer media.

Key Features

• Two standard bath volumes: 10 L (model HE10D) and 30 L (model HE30D), each with optimized geometry for consistent thermal distribution
• Dual-layer safety architecture: adjustable over-temperature cut-out switch + mechanical float-switch level protection to prevent dry-run operation
• Top-mounted digital controller with LED display (1 °C resolution), programmable timer (1–9999 minutes), and audible/visual high/low temperature alarms
• Integrated high-efficiency stirrer and low-thermal-mass heating elements, engineered to minimize thermal lag and maximize response fidelity
• Insulated, hinged protective lid (dual lids supplied with HE30D) reducing evaporative loss and operator exposure to elevated surface temperatures
• Optional HQ-series external circulation pumps (HQ10 for HE10D; HQ30 for HE30D), mounted directly onto the bath lid for rapid integration into closed-loop external systems
• EMC-compliant Class A emissions profile, suitable for shared laboratory environments with sensitive instrumentation

Sample Compatibility & Compliance

The HED series is validated for use with silicone oils (e.g., Dow Corning 200 Fluid, GE SF-96) and other chemically inert, high-flashpoint heat transfer fluids rated for continuous operation up to 260 °C. Bath materials—including the 316 stainless steel reservoir, enamel-fused carbon steel chassis, and fluoropolymer-sealed pump components—are selected for long-term compatibility with non-aqueous, oxidizing, and mildly acidic thermal media. The system conforms to DIN 58966 for temperature stability verification and meets CE marking requirements under the EU Machinery Directive 2006/42/EC and Electromagnetic Compatibility Directive 2014/30/EU. While not intrinsically rated for hazardous area use, its sealed construction and absence of ignition sources make it appropriate for controlled environments in upstream petroleum research and academic thermochemical laboratories operating under GLP-aligned protocols.

Software & Data Management

The HED Series operates as a standalone analog-digital hybrid platform with no embedded firmware-based data logging. Temperature setpoints, timer status, and alarm conditions are monitored locally via the front-panel LED interface. For integration into automated workflows, the unit supports optional analog voltage output (0–10 V DC) proportional to bath temperature—enabling connection to external PLCs, SCADA systems, or PC-based DAQ platforms compliant with IEEE 12207 or ISO/IEC 15288 systems engineering standards. All operational parameters—including heating cycle duration, maximum setpoint history, and alarm event timestamps—can be manually recorded in laboratory notebooks traceable to 21 CFR Part 11–aligned documentation practices when paired with validated procedural controls.

Applications

• Petroleum & energy research: crude oil viscosity profiling, asphalt binder testing, thermal aging of lubricants and drilling fluids
• Materials science: polymer melt rheology pre-conditioning, catalyst activation studies, high-temperature solvent extraction (e.g., Soxhlet variants)
• Pharmaceutical development: accelerated stability testing of lipid-based formulations, excipient thermal screening above 150 °C
• Academic physical chemistry: calorimetric reference baths, reaction calorimetry support, phase transition studies in molten salts and ionic liquids
• Industrial QA/QC: calibration of high-temperature probes and sensors per ISO/IEC 17025-accredited procedures

FAQ

What heat transfer fluids are recommended for continuous operation at 260 °C?
Silicone oils meeting ASTM D1259 or ISO 6743-12 specifications (e.g., Dow Corning 200 Fluid Grade 50,000 cSt) are validated for full-range operation. Mineral oils are not recommended above 180 °C due to oxidative instability.

Can the HED bath be used for open-bath immersion applications?
No. The HED series is engineered exclusively for closed-loop circulation or sealed-vessel immersion. Open-bath use violates its safety design and voids compliance with DIN 58966 thermal uniformity validation.

Is the HQ pump compatible with pressurized external circuits?
The HQ10 and HQ30 are centrifugal pumps rated for closed-loop, non-pressurized circulation only (max head 1.6 m water column). They are not rated for backpressure exceeding 0.1 bar gauge.

Does the unit support remote start/stop or Ethernet connectivity?
No native network interface is provided. Remote control requires external relay interfacing via the optional 0–10 V analog output and auxiliary dry-contact terminals (available upon request with OEM configuration).

What maintenance intervals are specified for long-term reliability?
Grant recommends biannual inspection of the float switch mechanism, annual recalibration of the digital controller against NIST-traceable references, and replacement of the silicone oil bath medium every 12–18 months under continuous 200 °C operation.