StableTemp Muffle Furnace by Cole-Parmer — Model 33858-65

Overview

The StableTemp Muffle Furnace Model 33858-65 is a precision-engineered, programmable box-type muffle furnace designed for consistent high-temperature thermal processing in research laboratories, quality control environments, and industrial R&D settings. Built to ASTM E1142 and ISO 9001-aligned thermal equipment specifications, it operates on resistive heating principles with fully embedded heating elements and dual-layer ceramic fiber insulation—ensuring minimal external surface temperature rise (<45 °C at ambient) and superior thermal retention. The furnace maintains stable setpoint temperatures from 100 °C to 1100 °C with ±1 °C accuracy and ±5 °C uniformity across the 5.2 L chamber (15.2 × 15.2 × 22.9 cm), validated per IEC 60068-3-5 thermal stability protocols. Its safety architecture includes automatic heater cutoff upon door opening, a removable spill-resistant hearth plate, and self-tuning PID control that eliminates overshoot during ramp-to-setpoint cycles—a critical feature for ashing, calcination, heat treatment, and gravimetric analysis workflows requiring repeatable thermal profiles.

Key Features

• Programmable controller with dual LED display showing real-time and setpoint temperatures simultaneously
• Up to 31 independent programs, supporting 126 total segments; supports copy/paste/edit/delete functions for rapid protocol iteration
• Auto-tuning PID algorithm optimized for load-dependent thermal dynamics, ensuring stable regulation under variable mass or emissivity conditions
• Dual-layer ceramic fiber insulation reduces standby heat loss by >40% compared to single-layer designs, improving energy efficiency and operator safety
• Full-embedded resistive heating elements ensure uniform radial and axial temperature distribution without hot spots
• RS485 serial interface (optional, factory-installed) enables integration into centralized lab automation systems for remote monitoring and data logging
• Removable stainless-steel hearth plate prevents corrosive residue or molten salt splashes from contacting insulation or heating elements
• Door interlock system de-energizes heaters within <100 ms of door actuation—compliant with EN 61000-6-2 and UL 61010-1 safety standards

Sample Compatibility & Compliance

The 33858-65 accommodates standard crucibles (up to 100 mL porcelain or alumina), ceramic boats, and quartz sample holders. Its inert muffle chamber—free of catalytic metals or volatile binders—ensures compatibility with ASTM D3174 (ash content), ASTM C114 (cement analysis), and USP <231> heavy metal testing procedures. All electrical components meet CE marking requirements and conform to IEC 61000-4 electromagnetic compatibility directives. For regulated environments, optional RS485 connectivity supports audit-ready data capture when paired with CALgraphix software—enabling electronic signatures, time-stamped event logs, and 21 CFR Part 11–compliant user access controls (role-based permissions, operation history, and change tracking).

Software & Data Management

When equipped with the RS485 port (Order Code 33858-90) and 7.6-m shielded cable (33858-92), the furnace interfaces with CALgraphix software—a Windows-based platform supporting multi-furnace supervision. CALgraphix provides real-time graphing of temperature vs. time, configurable alarm thresholds (e.g., deviation >±3 °C for >60 s), automated report generation (PDF/CSV), and virtual device mapping for distributed lab networks. It records all setpoint changes, program starts/stops, and fault events with ISO 8601 timestamps and operator IDs. Software configuration files are digitally signed and version-controlled, satisfying GLP/GMP documentation integrity requirements for method validation and equipment qualification (IQ/OQ/PQ).

Applications

• Gravimetric ash determination in food, pharmaceutical, and environmental samples (AOAC 923.03, EPA Method 200.2)
• Calcination of catalyst precursors and ceramic powders prior to XRD or BET analysis
• Thermal decomposition studies in materials science (TGA correlation, binder burnout)
• Heat treatment of metallurgical specimens for microstructural stabilization
• Residue ignition in wastewater sludge analysis (Standard Methods 2540F)
• Pre-conditioning of filters and crucibles per ASTM E2904 guidelines

FAQ

Is the RS485 interface pre-installed or field-upgradable?
The RS485 port must be factory-installed at time of order (Option Code 33858-90); it is not retrofittable due to internal wiring and firmware dependencies.
What is the maximum recommended sample mass for optimal uniformity at 1100 °C?
For ±5 °C uniformity across the chamber, maximum recommended cold-load mass is 1.2 kg; heavier loads may require extended soak times and empirical validation per your SOP.
Does the furnace support ramp-hold-soak programming with multiple cycles?
Yes—each of the 31 stored programs supports up to 126 segments, including ramp rates (°C/min), holds, and repeat loops (up to 999 cycles per program).
Can CALgraphix log data at sub-minute intervals?
Yes—sampling interval is user-configurable from 1 second to 60 minutes, with buffered storage ensuring no data loss during brief network interruptions.
Is NIST-traceable calibration documentation available?
Cole-Parmer provides optional factory calibration certificates (NIST-traceable, 5-point verification at 200/500/800/1000/1100 °C) with uncertainty budgets per ISO/IEC 17025 requirements.