Thermal-Stable Al2O3 Ceramic Thermocouple Protection Tubes Alumina Sheaths for High Temperature Sensor Components

Temperature sensors in furnaces, kilns and reactors need protection that stays gas tight, dimensionally true and chemically inert at extreme temperatures, because a failed sheath means a failed measurement and an unplanned shutdown. Our Thermal-Stable Al2O3 Ceramic Thermocouple Protection Tubes are manufactured from high purity alumina with a fully dense, gas tight wall that shields sensor elements from combustion gases, molten metals and corrosive atmospheres while transferring heat quickly enough for responsive measurement.

The material is chosen for its thermal stability: it neither softens nor distorts at continuous temperatures up to 1700 degrees Celsius, and its low thermal expansion prevents the slow dimensional drift that would allow gases to bypass the seal. Closed end tubes, double bore insulators and stepped assemblies are available to match any sensor construction.

• Gas tight protection: Dense impermeable wall isolates the sensor element from process gases and contaminants.
• Stable to 1700°C: Maintains strength and dimensional accuracy across the full operating range of noble metal thermocouples.
• Thermal shock tolerant: Withstands rapid insertion into hot furnaces and quenching during process upset conditions.
• Fast thermal response: High thermal conductivity and thin wall options give responsive temperature tracking.
• Chemical inertness: Resists attack by combustion products, sulfur bearing gases and most molten metals and salts.
• Electrical insulation: High resistivity prevents leakage currents that would corrupt millivolt sensor signals.
• Custom bores and lengths: Single, double and multi bore formats with closed or open ends manufactured to specification.

These sheaths protect temperature sensor components in heat treatment furnaces, ceramic kilns, glass melting, metal melting and holding furnaces, power plant flue gas monitoring, petrochemical reformers, incinerators and laboratory furnaces.

We supply complete protection assemblies including flanges, fittings and compression seals, and we can match the sheath geometry to any major thermocouple brand so replacements install without modification.

Long and thin tubes are packed in rigid cardboard tubes or wooden crates with foam cradles to prevent bending and chipping during transit.

Each batch is inspected for straightness, wall thickness, closed end integrity and surface quality, with reports provided on request.