ISOTECH Model 875 High-Temperature Dry Powder Bath
| Brand | ISOTECH |
|---|---|
| Origin | United Kingdom |
| Model | 875 |
| Temperature Range | 50 °C to 700 °C |
| Calibration Uncertainty | ±0.020 °C (k=2) at 300 °C |
| Application | Fixed-point calibration (In, Sn, Zn, Al points) and comparative thermometry |
Overview
The ISOTECH Model 875 High-Temperature Dry Powder Bath is a precision thermal calibration instrument engineered for metrological-grade temperature calibration across an exceptionally wide range—from 50 °C to 700 °C—without requiring media replacement. Unlike conventional salt baths or oil-based systems, the 875 employs a proprietary, thermally stable, finely graded dry powder medium housed within a hermetically sealed, double-walled stainless-steel chamber. Its operation relies on forced convection and optimized thermal mass distribution to achieve high axial and radial uniformity, enabling both comparative calibration (e.g., against reference PRTs or SPRTs) and fixed-point realization (including In, Sn, Zn, and Al ITS-90 defining points). The system is designed to meet the stringent requirements of national metrology institutes and accredited calibration laboratories operating under ISO/IEC 17025, with traceability to NPL and other BIPM-affiliated NMIs.
Key Features
- Continuous operational range from 50 °C to 700 °C using a single, maintenance-free dry powder medium—eliminating hazards associated with molten salts (e.g., thermal decomposition, corrosion, splashing) and organic fluids (e.g., oxidation, volatility, flammability).
- Hermetic enclosure with multi-stage particulate filtration ensures zero dust emission during operation, maintaining laboratory air quality and operator safety in compliance with UK COSHH and EU Directive 2004/37/EC (carcinogens and mutagens).
- Thermal stability ≤ ±0.005 °C over 30 minutes at 660 °C; axial uniformity ≤ ±0.015 °C over 60 mm immersion depth at 500 °C.
- Calibration uncertainty of ±0.020 °C (k = 2) at 300 °C and ±0.035 °C (k = 2) at 660 °C when used with a certified SPRT and validated measurement chain per ISO/IEC 17025 Clause 6.5.
- Integrated PID-controlled heating system with dual-zone thermal profiling and real-time deviation monitoring via redundant Pt100 sensors.
- Compatible with standard 6.35 mm (¼″) diameter probe sheaths and supports immersion depths up to 150 mm, conforming to ASTM E74-22 Annex A3 guidelines for probe positioning.
Sample Compatibility & Compliance
The Model 875 accommodates a broad spectrum of temperature sensing elements, including Standard Platinum Resistance Thermometers (SPRTs), Industrial Platinum Resistance Thermometers (PRTs), thermocouples (Types S, R, B, and C), and liquid-in-glass thermometers (LIGTs) with stem corrections applied per ISO 5725 and ASTM E220-21. Its sealed architecture eliminates cross-contamination risks, making it suitable for GLP and GMP environments where audit readiness is mandatory. All firmware and hardware configurations comply with IEC 61000-6-3 (EMC emissions) and IEC 61010-1:2010 (safety for electrical equipment for measurement, control, and laboratory use). Documentation includes full Declaration of Conformity (DoC), UKCA marking, and optional NIST-traceable calibration certificate (ISO 17025 accredited).
Software & Data Management
The 875 operates standalone or integrates with ISOTECH’s CalLab Suite v4.2—a Windows-based calibration management platform supporting 21 CFR Part 11-compliant electronic records, role-based user access, automated uncertainty budgeting (GUM-compliant), and audit trail generation. Raw temperature readings are timestamped, logged at configurable intervals (0.1–10 s), and exported in CSV, XML, or .cal formats compatible with MET/CAL, Thermo Scientific CalTrack, and LabWare LIMS. Firmware updates are delivered via encrypted USB key or secure HTTPS, with version rollback capability and SHA-256 integrity verification.
Applications
- Primary and secondary calibration of high-temperature reference standards in NMIs and ISO/IEC 17025-accredited labs.
- Fixed-point cell characterization and maintenance (In, Sn, Zn, Al) per ITS-90 specifications.
- Validation of furnace temperature uniformity profiles (per ASTM E2554 and IEC 60584-2).
- Thermometer type approval testing for aerospace (SAE AS4059), power generation (IEEE 1003), and nuclear instrumentation (ANSI N42.17B).
- Research into high-temperature sensor drift mechanisms and long-term stability assessment under controlled thermal cycling.
FAQ
Can the Model 875 be used for calibrating Type K thermocouples at 650 °C?
Yes—when paired with a calibrated SPRT reference and following the two-point comparison method outlined in ASTM E230/E230M, the system achieves expanded uncertainty ≤ ±0.12 °C (k = 2) at this condition.
Is the dry powder medium replaceable by the end user?
No—the powder is factory-sealed and not serviceable. Lifetime exceeds 10 years under recommended operating cycles (≤ 3 thermal cycles/day, max ramp rate 10 °C/min).
Does the unit support remote operation via Ethernet or RS-232?
Yes—standard Ethernet (TCP/IP) and optional RS-232 interfaces enable SCPI command set control and integration into automated calibration workstations.
What validation documentation is supplied with shipment?
Each unit ships with a Factory Acceptance Test Report (FATR), as-built mechanical drawings, CE/UKCA DoC, EMC test summary, and a 12-month warranty covering materials and workmanship.
