【Weekly Question 20090615】Material issues related to Type B thermocouple compensation wires (generous prizes await you)

Type B thermocouples possess the highest accuracy, best stability, a wide temperature measurement range, a long service life, and a high upper temperature limit among all thermocouple types. It is suitable for use in oxidative and inert atmospheres, and can also be used briefly in vacuum, but it is not suitable for reducing atmospheres or atmospheres containing metal or non-metal vapors. A significant advantage of Type B thermocouples is that no compensation wire is required, as the thermoelectric potential remains below 3 μV in the range of 0–50°C.

Type B has never been used; we usually use types K, E, and T. The common model specifications are EX-RVVP 2X1.5 and KX-RVVP 2X1.5

Type B thermocouples are platinum-rhodium 30-platinum-rhodium 6 thermocouples, which include platinum-rhodium 30-platinum-rhodium 6, WRB or WRR, WRBK or WRRK. The material of the protective tube is non-metallic

Both the positive and negative terminals of B-type thermocouple compensation wires are made of platinum-rhodium alloy! The thermocouples used in our unit are mainly K.J type thermocouples; B type thermocouples are rarely used

The B division has an extremely low thermoelectromotive force at room temperature, so a compensation wire is generally not used during measurement. Its long-term operating temperature is 1600°C, and the short-term temperature is 1800°C. It can be used in oxidative or neutral atmospheres, as well as for a short period of time under vacuum conditions.

B-type thermocouples are made of platinum-rhodium 30 and platinum-rhodium 6; they are rarely used. When in use, a BC-type compensation wire is employed, with the alloy wire of this compensation wire being copper.

B-type thermocouples are made of platinum-rhodium 30 and platinum-rhodium 6; when using them, compensation wires of type B should be purchased, although ordinary copper wires can also be used as compensation wires, and practice has shown that they work well.

This post was last edited by Mobei Yihai on 2009-6-18 at 11:28. The platinum-rhodium 30-platinum-rhodium 6 thermocouple (Type B thermocouple) is a noble metal thermocouple. The diameter of the wire is specified at 0.5 mm, with an allowable deviation of -0.015 mm. The nominal chemical composition of its positive electrode (BP) is a platinum-rhodium alloy containing 30% rhodium and 70% platinum, while the negative electrode (BN) is also a platinum-rhodium alloy containing 6% rhodium; hence it is commonly referred to as a dual-platinum-rhodium thermocouple. The maximum continuous operating temperature for this thermocouple is 1600°C, while the maximum short-term operating temperature is 1800°C. 　　 　　Type B thermocouples possess the highest accuracy, best stability, a wide temperature measurement range, a long service life, and a high upper temperature limit among all thermocouple types. It is suitable for use in oxidative and inert atmospheres, and can also be used briefly in vacuum, but it is not suitable for reducing atmospheres or atmospheres containing metal or non-metal vapors. A significant advantage of Type B thermocouples is that no compensation wire is required, as the thermoelectric potential remains below 3 μV in the range of 0–50°C. If adopted, model: BC; electrode material: copper ； The color of the negative electrode is generally gray.

Model: ZR-IA-DJFPVP 2*1.5 Material: Copper

The thermocouples used in our company are mainly K-type thermocouples; we have never used B-type ones! Type B thermocouples are platinum-rhodium 30-platinum-rhodium 6 thermocouples, with a maximum operating temperature of 1600°C. Both the positive and negative wires of these thermocouples are made of platinum-rhodium alloy. Type B thermocouples do not require compensation wires, as their thermoelectric potential is less than 3 μV within the range of 0–50°C.