Thermocouples manufactured from noble metals offer improved accuracy and stability over base metal thermocouples and support continuous operation at higher temperatures. Most commonly they are manufactured from combinations of Platinum and Rhodium. These precious metals are very rare and because of their intrinsic value, their cost is higher than base metals and can vary depending on market conditions. While the upfront cost may be relatively high, the wire that drives that cost has value even when it exceeds its useful performance life or is no longer needed. CEL’s Exchange Programs and Scrap Reclaim Programs are unmatched throughout the industry, thus upfront cost is high but (net) cost is much more palatable when factoring in the scrap value applied to future purchases (replacement thermocouples) or the credit of the recovered value.
When selecting the proper thermocouple type, consideration must be given to length of service, temperature, atmosphere, response time and cost. Also, be sure to the thermocouple type that is chosen is compatible with the instrumentation and equipment being used for the process. Industry standards may further limit the choice of thermocouple types, number of uses or limits of error. CEL’s sales and applications staff has decades of experience in the manufacture and use of thermocouples to aid in the choice and design of the correct thermocouple. CEL expertise in manufacturing and extensive inventory allows for built-to-order assemblies while simultaneously maintaining industry-best lead times.
Insulator materials, protection tube varieties, secondary coatings (tungsten) straight and bent assemblies, termination options (plugs, jacks, blocks, heads, soft wire leads, extension wire), process fittings, SAT Port, Single or Dual Junctions, wire diameters with other options upon request. Available in all standard ANSI configurations
Platinum-rhodium vs platinum thermocouples are especially well suited for use in an oxidizing atmosphere. Thermocouples can be used bare in clean, oxidizing atmospheres where no forced airflow is present. However, in areas where contaminants and a high rate of air flow are present, service life can be increased using insulators and protection tube. High-purity alumina tubes are recommended. Thermocouples are susceptible to contamination by metallic vapors or other volatile substances such as lead and zinc. The problems of contamination are increased in a reducing atmosphere, especially when silicon or sulfur is present.
Insulators and protection tubes are available in a multitude of materials and configurations. Most commonly Alumina and Mullite. Mullite has good resistance to thermal shock yet poor resistance to mechanical shock and should only be mounted in a vertical orientation. Alumina has fair resistance to both thermal and mechanical shock. It is impervious to gases up to 3200F. Inconel, and exotic protection tubes are also available including, Halsic, Hastelloy, Hexoloy, Silicon Carbide, Metal Ceramic (LT1), Sialon, Tercod, Fused Quartz, Molybdenum, Zirconia, Tantalum, Cast Iron and many others.
Noble Metal Assemblies
Noble Metal Assemblies, or NMAs, are complete assemblies that are custom-built and shipped ready to use. Beginning with the element, the thermocouple assembly is then built around it to achieve the required balance of accuracy, durability, lifetime, responsivity, and cost. Options include built-on process fittings for easy mating to any furnace and terminal blocks or soft leads to wire/plug directly into instrumentation. CEL supplies drop-in replacements for many commercial furnace thermocouples. Our NMAs are typically built to support replacement of the wire should the protection tube outlast the element to further maximize value.
- Durable thermocouple option for rugged but high temperature applications up to 3100°F
- Noble Metal
- Platinum-based
Applications
Forging, Blast Furnaces, Steel Production, Tunnel Kilns & High-Temperature Periodic Kiln
Technical Data
Calibration: B, R & S
Wire Gauge: 24 Gauge (Standard)
Protection Tubes: Alumina, Mullite, Silicon Carbide, Re-Crystallized Silicon Carbide & Inconel
Termination: Multiple Termination Options
Hardware: Multiple Mounting Hardware Options
Certification: Individual or Lot Certification; Special Limits of Error
Noble Metal Elements
Noble Metal Elements (Platinum & Rhodium) may be used as a stand-alone thermocouple, or as a replaceable component of a Noble Metal Assembly. Typically supplied in Types S, R, or B, NME’s are reliable thermocouples for high-heat applications.
Technical Data
Calibration: B, R & S
Wire Gauge: 24 Gauge (standard)
Insulators: Alumina & Mullite
Termination: Multiple Termination Head Options
Certification: Individual or Lot Certification; Special Limits of Error
Reduced diameter tips are also available in this configuration.
Noble Metal Thermocouple Additional Services
Calibration & Certification Lab
Repair & Recalibration
Exchange Programs
Engineering Services
- Value-added Services
- Product Tagging & Serialization
Product Kitting