LAC LH Series Laboratory Muffle Furnace

Overview

The LAC LH Series Laboratory Muffle Furnace is a precision-engineered box-type thermal processing instrument designed for controlled high-temperature applications in research laboratories, quality control environments, and materials testing facilities. Operating on the principle of radiant heat transfer within a fully insulated, sealed muffle chamber, the furnace isolates samples from direct contact with heating elements—ensuring contamination-free thermal treatment and preventing corrosive volatiles from degrading internal components. With a maximum operating temperature of 1340 °C and ±1 °C temperature stability across the full working range, the LH series meets stringent requirements for ashing, calcination, sintering, heat treatment, and residue analysis per ASTM E1867, ISO 562, and USP . Its robust frameless construction, using corrosion-resistant stainless steel cladding and high-purity mineral fiber insulation, enables rapid thermal response while maintaining low external surface temperatures (<50 °C at 1340 °C operation), minimizing ambient heat load and enhancing lab safety.

Key Features

• Frameless structural design with seamless, hooped austenitic stainless steel mantle for long-term dimensional stability and resistance to thermal cycling fatigue
• Firebrick-lined muffle cavity fully encased in layered mineral wool insulation and rigid ceramic fiber boards—achieving thermal conductivity <0.09 W/m·K at 1000 °C
• Top-hinged, spring-assisted manual door with integrated safety limit switch that de-energizes heating circuits upon opening
• S-type platinum/rhodium thermocouple mounted on the rear chamber wall for representative temperature feedback and traceable calibration
• HT40AL digital controller (standard) with PID algorithm, real-time ramp/soak programming, and data logging via optional RS-232/RS-485 interface
• Industrial-grade solid-state relay (SSR) for silent, zero-crossing switching—eliminating electromagnetic interference and mechanical wear associated with electromechanical contactors
• Forced-air cooling system for electronic components, extending controller and power supply service life under continuous high-temperature duty cycles
• Blue-tinted borosilicate observation window with integrated thermal shielding, enabling safe visual monitoring without compromising chamber integrity

Sample Compatibility & Compliance

The LH furnace accommodates a broad spectrum of sample forms—including crucibles (alumina, quartz, platinum), ceramic boats, graphite holders, and powdered or granular specimens—without risk of cross-contamination. Its sealed muffle architecture prevents interaction between sample off-gases and heating coils, making it suitable for ashing organic matrices (e.g., food, pharmaceuticals, polymers) per AOAC 990.18 and EPA Method 3050B. All electrical and thermal subsystems comply with IEC 61010-1:2010 for laboratory equipment safety, and the furnace’s construction conforms to EN 60519-12 for industrial electroheating installations. When equipped with the INDUSTRY controller and validated temperature logging software, the system supports 21 CFR Part 11-compliant electronic records, including user authentication, audit trail generation, and immutable cycle archiving—essential for GLP and GMP-regulated environments.

Software & Data Management

The standard HT40AL controller provides local setpoint adjustment, real-time temperature display, and basic ramp/soak functionality. For advanced process documentation, the optional INDUSTRY controller offers up to 30 independent thermal programs, each containing 15 definable segments with individual ramp rates (0.1–30 °C/min), dwell times (0–99 h 59 min), and event-triggered outputs (e.g., gas purge activation, exhaust fan start). Integrated RS-232/RS-485 communication enables bidirectional data exchange with third-party SCADA or LIMS platforms. The companion temperature monitoring software delivers time-stamped CSV export, graphical cycle replay, deviation alerts, and PDF report generation—with built-in validation templates aligned with IQ/OQ protocols for laboratory instrument qualification.

Applications

• Gravimetric ash content determination in food, feed, and environmental samples (ISO 2171, ASTM D3174)
• Preparation of oxide catalysts and ceramic precursors via controlled calcination
• Thermal decomposition studies in polymer and composite material R&D
• Residue analysis following solvent extraction or acid digestion workflows
• Heat treatment of metallurgical test coupons and refractory standards
• Inert-atmosphere sintering when coupled with nitrogen or argon gas supply kits

FAQ

What is the maximum recommended continuous operating temperature?
The LH series is rated for continuous operation at 1340 °C, with thermal soak capability verified over 100 hours per IEC 60519-12 accelerated life testing.
Can the furnace be used under reducing or inert atmospheres?
Yes—optional gas inlet ports and flow regulators support N₂, Ar, or forming gas (5% H₂/95% N₂) purging; however, reduction atmospheres require compatible crucible materials (e.g., Mo, SiC) and are not covered under standard warranty.
Is the HT40AL controller compliant with FDA 21 CFR Part 11?
No—the HT40AL lacks electronic signature and audit trail capabilities; compliance requires the INDUSTRY controller with validated software and system-level IQ/OQ documentation.
What maintenance intervals are recommended for optimal performance?
Inspect door gasket integrity and thermocouple calibration every 6 months; clean interior chamber and ventilation ducts quarterly; verify SSR functionality and cooling fan RPM annually.
Does the furnace include CE marking and Declaration of Conformity?
Yes—all LH models shipped from the Czech facility carry CE marking under the EU Machinery Directive 2006/42/EC and Low Voltage Directive 2014/35/EU, accompanied by a manufacturer-issued DoC valid for the EU and UKCA markets.