The Elmec thermocouple operates on the principle that clear quartz glass is an excellent transmitter of infrared radiation. Infrared heaters are one of the most efficient and rapid means of transferring heat into an object.
By placing a clear quartz tube over the heating wire and keeping the thermocouple in direct contact with the tube, the heat is rapidly transferred into the thermocouple, and so the temperature change in the element is closely followed. This system prevents displacement of thermocouple during the casting process..
Advantages of the Thermocouple
By using a quartz tube any difficulties with regard to electrical interference between the heating wire and the thermocouple are avoided as quartz is an excellent insulator. With the thermocouple permanently in contact with the quartz tube, which is of consistent diameter, the distance between the thermocouple and the heating wire is maintained constant for all elements. This in turn will lead to a consistency in the thermocouple readings of the ceramic elements.
The thermocouple also gives an enhanced response time as can be seen from the results shown in the graph. As can clearly be seen, the thermocouple has a much faster response time and so gives a more representative indication of the heating element temperature.
This is quite advantageous to today's production systems which demand increased temperature control as a way of reducing operating times and increasing productivity.
Elmec manufactures many different wire lead lengths with a range from 100mm (the standard wire length) to a maximum of 300mm.