pyrometric cone
Date1890-1940
Inventory Number4807
ClassificationCeramics
Subject
Attributed to
Norton Company
founded 1885
Cultural Region
Place of Origin
Dimensions2 x 5 x 2 cm (13/16 x 1 15/16 x 13/16 in.)
Material
DescriptionClay pyramid with broken tip.
Signedunsigned
Inscribedon side: 021
Curatorial RemarksObjects 4795 to 4808 came originally in a box labeled "Norton Aluminum Refractories" .
FunctionPyrometric cones, also called Seger or Orton pyrometer cones, are used by ceramics manufacturers as indicators of the temperature inside an oven. They are made of different materials with different, known melting points, and are placed inside the oven. One can determine the temperature in the oven from which of them are bending. The indicators are made of conical (generally pyramidal) shapes so that the melting occurs first at the tip progressing down from it. They are supposed to bend over to one side, and different stages in this bending process relate to the temperature in the oven.
They come in a scale developed by Seger (in integer numbers) referred to as "cone number", and are considered a better indicator for ceramics ovens than pyrometers as they are witness of the whole heating process rather than just an instant.
Due to the use of these cones, "cone number" became a standard measure of the refractoriness of materials.
For a detailed explanation of their use and scale, see Frank Hamer and Janet Hamer, The Potter's Dictionary of Materials and Techniques, 5th ed. (A & C Publishers, Ltd, 2004), pp.77-79. Available online at Google Books here.
They come in a scale developed by Seger (in integer numbers) referred to as "cone number", and are considered a better indicator for ceramics ovens than pyrometers as they are witness of the whole heating process rather than just an instant.
Due to the use of these cones, "cone number" became a standard measure of the refractoriness of materials.
For a detailed explanation of their use and scale, see Frank Hamer and Janet Hamer, The Potter's Dictionary of Materials and Techniques, 5th ed. (A & C Publishers, Ltd, 2004), pp.77-79. Available online at Google Books here.
