Measurement of high temperatures, greater than 1000 C, using ceramic based thermocouples can be a well known process. To carry out this successfully the resistance wires throughout the thermocouple need to be insulated and guarded.
The use of Ceramic materials to protect the platinum based wire is a technique which has been used for quite some time, because of the exceptional heat resistant properties of such materials. The thermocouple sensors is considered the most popular heat measurement implement and is useful for measuring the temperature within a furnace, typically getting used to the melting or heat treatment of metal or indeed for manufacturing ceramic products.
The ceramic components in the typical thermocouple device would be the outer protection tube that is certainly exposed to the furnace. In some instances multiple tubes are utilized inside one another to supply the degree of insulation and protection required.
Ceramic insulators (Tubes with 2 or maybe more core holes through them) can also be accustomed to isolate the 2 or more wires that visit the bi-metallic joint with the head which is the point from where sens0rs temperature is measured.
The typical material used for your tube is actually a 99.7% alumina material, impervious tube, which can be attached typically to a metal thermacouple head, containing a terminal block that is utilized for connecting to some standard wire towards the instrumentation. In the less demanding heat atmosphere a mullite tube may be used being a cheaper alternative, which can work sufficiently around 1600 ‘oc. The mullite tube is likewise an impervious tube and it has 60% alumina content.