Measurement of high temperatures, higher than 1000 C, using ceramic based thermocouples is actually a well-established process. To carry out this successfully the resistance wires throughout the thermocouple should be insulated and guarded.
The usage of Ceramic materials to protect the platinum based wire is a technique which has been used for quite some time, due to exceptional heat resistant properties of such materials. The cartridge heater with thermocouple is easily the most commonly used heat measurement implement and is utilized for measuring the temperature inside of a furnace, typically being used for your melting or heat treatment of metal or indeed for manufacturing ceramic products.
The ceramic components in the typical thermocouple device will be the outer protection tube which is subjected to the furnace. Sometimes multiple tubes are employed inside the other to deliver the degree of insulation and protection required.
Ceramic insulators (Tubes with 2 or higher core holes through them) will also be accustomed to isolate the several wires that visit the bi-metallic joint on the head which is the point that sens0rs temperature is measured.
The common materials for that tube is actually a 99.7% alumina material, impervious tube, which can be attached typically to a metal thermacouple head, containing a terminal block which is used in order to connect to some standard wire for the instrumentation. In a less demanding heat atmosphere a mullite tube may be used like a cheaper alternative, which will work sufficiently as much as 1600 ‘oc. The mullite tube is likewise an impervious tube and contains 60% alumina content.