KILNS & FURNACES
Electric in air to 1800°C • Research • Heat treatment
Controlled atmosphere • Melting • Gas, Natural/LPG to 2300°C
Tetlow Kiln Pty. Ltd. ABN: 26 166 832 300 54 Howleys Road, Notting Hill, 3168 Victoria Australia
T: +61 3 8545 8296 F: +61 3 9544 2723 E: info@tetlow.com.au www.tetlow.com.au
12.6 THERMOCOUPLES
Thermocouples are the “working end” of the pyrometer. It projects inside the kiln and
generates the current, which is measured by the instrument fixed outside the kiln.
It consists of two different metals joined together at one end, called the junction, all located
inside a ceramic sheath. The junction (which is the end located inside the kiln) is where the
temperature is sensed. The thermocouple gives the temperature only in the immediate
vicinity of the junction. If the thermocouple is “shaded” (e.g. by having too much ware or
shelving placed too close to it) or if it does not protrude sufficiently into the kiln from the wall,
it will give a poor indication of the actual kiln temperature. This can lead to either over-firing
or under-firing, which can affect the ware being fired, and can also (with over-firing) result in
kiln damage.
You must not pack or place items within 50 mm from the thermocouple, and the
thermocouple must protrude from the wall by between 10 mm and 20 mm.
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