Duchin Patent Product:
Single-Core Mineral-Insulated Thermocouple
Overview
Conventional thermocouples contain two or more thermoelements inside the protective sheath, resulting in a relatively large outer diameter. The thermo-wires themselves are thin: high-temperature models are usually rigid and non-bendable, while small-diameter flexible types cannot withstand high temperatures.
The Single-Core Mineral-Insulated Thermocouple has only one thermo-element inside its protective sheath. The positive and negative poles are separately insulated and sheathed. The thermo-wire, insulation material, and metal sheath form an integral, non-detachable compact structure, with a typical diameter of φ1 to φ4 mm.
As a third-generation thermocouple developed from assembled and conventional mineral-insulated thermocouples, it features higher accuracy, higher reliability, and easier fabrication and installation. It is a universal thermocouple suitable for a wide range of applications.
It performs especially well in 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 demands thermocouple accuracy within ±1.1 °C, together with both high-temperature capability and excellent flexibility. The single-core mineral-insulated thermocouple fully meets these requirements.
This product has won the Gold Medal at the China Patent Expo hosted by the China National Intellectual Property Administration. It has been recognized as a Key New Product and High-Tech Product by the Chongqing Municipal Science and Technology Commission.
In 2007, it was included in the national standard development 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 been reported by CCTV, Science and Technology Daily, and various industrial journals.
Technical Features
1. High Reliability
The main failure mode of thermocouples is insulation breakdown.The single-core mineral-insulated thermocouple features separate insulation and sheath structures for the positive and negative poles, which greatly improves insulation reliability and reduces damage to thermo-wires during processing. This ensures stable temperature measurement and long-term performance.
2. High Accuracy
The thermoelectric characteristics of traditional thermocouples often shift during manufacturing, making final accuracy difficult to control.With separated positive and negative poles, the single-core design allows optimal pairing of thermoelements, enabling the production of thermocouples with any required accuracy level.
3. High Pass Rate
The main cause of scrap in thermocouple production is out-of-tolerance thermoelectric voltage. Traditional thermocouples typically have a pass rate of only about 90%.Since the positive and negative poles are produced independently and optimally matched, the single-core mineral-insulated thermocouple eliminates scrap due to thermoelectric voltage deviation, achieving a nearly 100% pass rate.
4. Easy to Manufacture and Use
The thermo-wire diameter of the single-core mineral-insulated thermocouple is relatively thick, making welding and fabrication much easier.It solves the long-standing conflicts of traditional designs:
"High temperature requires a thick, rigid body"
"Small diameter is hard to weld"
It satisfies applications that demand both high-temperature measurement and high flexibility, and allows users to perform in-house fabrication, re-processing, and repeated reuse conveniently.