MI Thermocouples — Type K & J
Mineral Insulated (MI) Type K and J thermocouples are built for reliability in demanding industrial applications where flexibility, vibration resistance, and fast thermal response are essential. Furn-Tek supplies MI thermocouples custom-built to your spec — cut to length, sheathed, terminated, and ready for harsh-duty environments.
Product Specification
Sheath Material:
Inconel 600, SS304, SS316, or SS310
Insulation:
High-purity magnesium oxide (MgO) for dielectric strength and heat transfer
Conductor Types:
- Type K: Chromel vs. Alumel – up to 1,250 °C
- Type J: Iron vs. Constantan – up to 750 °C
Outer Diameters:
Typically 1.5 mm – 8 mm
Custom lengths:
Available from 100 mm up to several meters
Lead Termination:
Bare wires, plugs, junction boxes, or stainless braided cable
Junction Type:
Grounded, ungrounded, or exposed
Applications:
- Furnace tube temperature monitoring
- Metalworking and heat treatment
- Rotary kilns and combustion chambers
- Plastic extrusion and injection molds
- Power plants and exhaust gas measurement
Why MI?
- Highly flexible — bends without breaking insulation
- Fast response time — direct thermal contact
- Shock and vibration resistant
- Compact diameter — fits tight spaces
- Stable over time — long lifespan under cyclic duty
Built to Spec:
Furn-Tek manufactures MI sensors in Type K and Type J to match your exact process needs — including termination, sheath, tip configuration, length, and response time requirements.