MineraI Insulated Thermocouples OMEGA （MineraI绝缘热电偶ω）.pdfVIP

The Choice Of Sheathing For MineraI Insulated Thermocouples H.L. Daneman, P.E. INTRODUCTION consists of Nicrosil plus 0.15% due to metal fatigue. On heating to 900 ºC, The mineral-insulated integrally metal- magnesium. It is reported (ref. 4) to exhibit the thermal expansion of Nisil differs from sheathed (MIMS) form of thermocouple less spalling and probably have a longer SS 304 by 0.4% of length. Nicrosil has consists of matched thermocouple wires life than some Nicrobell version(s) tested. only 0.05% difference in thermal surrounded by insulating material (typically Nicrosil, itself, does not have satisfactory expansion compared to Nisil (the leg most MgO) compacted by rolling, drawing or resistance to reducing atmospheres, such likely to fracture). A sheath of Nicrosil, swaging until the sheath is reduced in as encountered in most combustion or Nicrosil + or Niobell would therefore induce diameter. The advantages of MIMS many heat treating processes. Other less metal fatigue in either leg of the Type thermocouples are: adaptations of Nicrosil for use as sheath N thermocouple than would stainless steel. • Chemical isolation of wires from the material (such as Nicrobells B, C and D) surrounding atmosphere. can be expected to deal with typical COMPOSITION • Shielding of thermoelements from nonoxidizing atmospheres. Composition changes in SS sheathed sources of electrical interference. CONTAMINATION