Conventional thermocouple sleeves contain two or more thermoelements, resulting in generally large sleeve diameters. The thermoelements themselves are thin: those for high-temperature measurements are usually thick and inflexible, while small-diameter and flexible ones are generally limited to low-temperature applications.
The protective sleeve of a single-core mineral insulated thermocouple contains only one thermoelement. The positive and negative poles are separately insulated and sleeved, forming an inseparable, compact entity consisting of the thermoelement, insulating material, and metal sheath, with a typical diameter ranging from φ1 to φ4 mm.
Developed as the third-generation thermocouple based on assembled thermocouples and conventional mineral insulated thermocouples, the single-core mineral insulated thermocouple features higher accuracy, greater reliability, and easier fabrication and application, making it a universal thermocouple.
It is particularly suitable for temperature uniformity testing of large heat treatment furnaces and heat treatment of large forgings and castings. For example, the aviation manufacturing industry requires compliance with the American AMS2750 standard, which specifies thermocouple accuracy of ±1.1℃, demanding both high-temperature measurement capability and excellent flexibility. The single-core mineral insulated thermocouple fully meets these requirements.
This product has won the Gold Medal of China Patent Expo sponsored by the China National Intellectual Property Administration. It has been recognized as a Key New Product and a High-Tech Product by the Chongqing Municipal Science and Technology Commission. In 2007, it was included in the national standard formulation plan by the Standardization Administration of China. In 2008, it was listed in the National Torch Program by the Ministry of Science and Technology. It has also been reported by CCTV, Science and Technology Daily, and various industry journals.
Technical Performance Features
High ReliabilityInsulation breakdown is the primary failure mode of thermocouples. Thanks to the independent insulation and sheath structure for the positive and negative poles, the single-core mineral insulated thermocouple improves insulation reliability, reduces thermoelement damage during processing, and thus enhances temperature measurement reliability and stability.
High AccuracyThe thermoelectric characteristics of traditional thermocouples often change during manufacturing, making finished product accuracy difficult to control. With separated positive and negative poles, the single-core mineral insulated thermocouple allows optimized pairing of the positive and negative elements, enabling the production of thermocouples with any required accuracy level.
High Qualification RateThermo-electromotive force (EMF) deviation is the main cause of scrap in thermocouple manufacturing. The qualification rate of traditional thermocouples is generally only about 90%. Since the positive and negative poles of the single-core mineral insulated thermocouple are produced independently and optimally paired, there is no scrap due to EMF deviation, resulting in a 100% qualification rate.
Easy Fabrication and ApplicationThe relatively large diameter of the thermoelement facilitates welding, solving the contradictions of traditional thermocouples:"High temperature requires thick diameter" and "Small diameter is difficult to weld".It satisfies applications requiring both high-temperature measurement and excellent flexibility, and enables users to manufacture thermocouples in-house, reprocess and reuse them repeatedly.