Platinum-rhodium thermocouple, which has the advantages of high temperature measurement accuracy, good stability, wide temperature measurement area, long service life and so on, is also called high temperature precious metal thermocouple. It is widely used in the fields of iron and steel, metallurgy, petrochemical, glass fibre, electronics, aviation and aerospace.
However, it is difficult to adapt to complex environments and narrow space areas that require bending and short thermal response time due to its reduced strength at high temperatures and its sensitivity to environmental pollution.
Precious metal armoured thermocouple is a new type of temperature measurement material developed on the basis of precious metal thermocouple, which has the advantages of vibration resistance, high pressure resistance, resistance to chemical corrosion of the medium, can be bent, short response time and durability.
Precious metal armoured thermocouple mainly consists of precious metal casing, insulating materials, dipole wire materials. It usually filled with magnesium oxide or other insulating materials between the precious metal casing and the dipole wire, in the case of maintaining high-temperature insulation, the dipole wire is in a gas-tight state, that so as to prevent the thermocouple from corrosion and deterioration due to the air or high-temperature gas. (the structure picture of thermocouple wire is as follows)