MINOX Thermocouples are thermocouple wires with mineral insulation lightly compacted about the conductors and encased in a metal sheath. MINOX Assemblies are specified because of their strength, protection against corrosion and contaminating atmospheres, and ability to be spring loaded to ensure tip contact at well bottom. The output from the element may be directly connected to a variety of thermocouple temperature measuring instruments.

• Standard Specifications:
  • MINOX Thermocouple Configurations:
    • Three configurations are offered. A well-type assembly with a nipple coupler; a welltype assembly with a nipple and union coupler; and a bare element-type assembly. The bare element-type assembly has a hex-head nipple with 1/2 NPT external thread welded on sensor for process mounting and mounting to connection head.
  • Sensor Type:
    • Single or Dual Element
  • Temperature Limits:
    • The maximum temperature limit is determined by the lowest upper range limit (URL) of the element, connection head, or sheath.
    • ELEMENT: Refer to Performance Specifications table above.
    • CONNECTION HEAD: -40 and +105°C (-40 and +220°F)
    • 316 SS SHEATH: -200 and +870°C (-320 and +1600°F)
    • INCONEL SHEATH: -200 and +1150°C (-320 and +2100°F)
  • Calibration:
    • ANSI MC 96.1, Types K, N, J, E, or T, as specified.
  • Grounded Measuring Junction:
    • The thermocouple wires are welded to the internal surface of the sheath tip.
  • Isolated Measuring Junction:
    • Thermocouple wires are electrically insulated from the sheath. Recommended for most applications.
  • Insertion Length, A, U, or U +T:
    • 90 to 914 mm (3.5 to 36 in) standard; nonstandard lengths to 7.6 in (300 in) available, see Model Code, and Dimensions-Nominal sections.
  • Sensitive Length:
    • 40 mm (1.6 in) minimum, measured from closed end.
  • Sheath Sealant:
    • Epoxy compound applied at open end of sheath to prevent entry of moisture.
  • Sheath Outside Diameter (O.D.):
    • 6.35 mm (0.250 in). Note that a well inside diameter (I.D.) of 6.60 mm (0.260 in) is required.
  • Internal Insulation:
    • Glass fiber over sensitive length; high-purity aluminum oxide powder over remaining length.
  • Construction:
    • All welded and moisture sealed, 316 ss for temperature up to 870°C (1600°F), and Inconel 600 for temperatures up to 1150°C (2100°F).
  • Wiring:
    • Refer to Figure 2 for terminal block configuration.