BLMI Mineral Insulated Metal Sheath Thermocouple Probes w/Bare Leads

 Supported Applications

The Omega BLMI Series consists of Mineral Insulated Metal Sheath Thermocouple Probes with bare leads, designed for temperature measurement in industrial processes. These probes utilize high-purity magnesium oxide insulation and SLE-class materials to meet or exceed ANSI/ASTM-E-230, ASTM-E-608, and BS/EN 61515 standards.

Operating Conditions & Performance

The series supports multiple thermocouple calibrations with specific upper temperature guidelines based on sheath material and diameter. Standard epoxy-sealed cold ends are rated to 175°C (350°F), while high-temperature versions feature ceramic cement cold ends rated to 1204°C (2200°F). Measurement ranges documented in the specification table include:

• J Calibration: 260°C (500°F) to 721°C (1330°F)
• K Calibration: 899°C (1650°F) to 1204°C (2200°F)
• T Calibration: 316°C (600°F) to 371°C (700°F)

Probes are subjected to a leak test at the welded thermocouple junction with pressurization greater than 2.5 MPa (362 psi). To pass insulation resistance tests according to ASTM specs, probes must achieve at least a 1 GΩ reading.

Configuration Options

The BLMI series is configurable across sheath materials, diameters, junction types, and lengths. Probes feature bare leads measuring 19 mm (¾"). Available configurations include:

• Sheath Materials: 304 SS, 310 SS, 316 SS, Inconel® 600, Super OMEGACLAD® XL
• Diameters: 1/16" (1.59 mm) to 1/4" (6.35 mm)
• Junction Types: Grounded, Exposed, Ungrounded
• Cold-End Seals: Epoxy or Ceramic Cement
• Lengths: Standard lengths of 150 mm (6"), 300 mm (12"), and 450 mm (18"); custom lengths available for probes over 12" upon consultation with Sales.
• Dual Element Option: Add suffix "-DUAL" to model number

Accessories include ceramic terminal blocks, compensated spade lugs, TX93A ultra-miniature transmitters, fiberglass sleeving (up to 480°C / 900°F), and BRK and SSLK compression fittings.

Key Product Differences

The series distinguishes between standard epoxy-sealed probes for lower temperature applications and high-temperature versions with ceramic cement cold ends. Model numbers follow the format BLMI-<Sheath Material>-<Calibration>-<Sheath Diameter>-<Junction Type>-<Probe Length>. For example, a mineral-insulated grounded probe with 316 SS sheath and 24" length is designated BLMI-XL-K-316-G-24. Junction types are specified by suffix: (G)rounded, (E)xposed, or (U)ngrounded.