Measurement of high temperatures, higher than 1000 C, using ceramic based thermocouples is really a well established process. To do this successfully the resistance wires in the thermocouple need to be insulated and guarded.
The use of Ceramic materials to shield the platinum based wire is a method which has been used for many years, as a result of exceptional heat resistant properties of the materials. The temperature controller is considered the most commonly used heat measurement implement and is used for measuring the temperature within a furnace, typically being utilized for that melting or heat management of metal or indeed for manufacturing ceramic products.
The ceramic components within a typical thermocouple device would be the outer protection tube that is certainly subjected to the furnace. In some instances multiple tubes are utilized inside each other to provide the level of insulation and protection required.
Ceramic insulators (Tubes with 2 or higher core holes through them) will also be utilized to isolate the 2 or more wires that go to the bi-metallic joint in the head the point from which sens0rs temperature is measured.
The typical materials for the tube is 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 to the instrumentation. Inside a less demanding heat atmosphere a mullite tube can be utilized like a cheaper alternative, which can work sufficiently approximately 1600 ‘oc. The mullite tube is also an impervious tube and it has 60% alumina content.