Pyrometric device


Pyrometric devices gauge heatwork when firing materials inside a kiln. Pyrometric devices do not measure temperature, but can report temperature equivalents. In principle, a pyrometric device relates the amount of heat work on ware to a measurable shrinkage or deformation of a regular shape.
Care should be taken with the interpretation, as some naively assume they are a measure of temperature alone.

Types

; Rings
; Bars
; Cones
; Discs

History

In 1782, Josiah Wedgwood created accurately scaled pyrometric device, with details published in the Philosophical Transactions of the Royal Society of London in 1782. This led him to be elected a fellow of the Royal Society.
The modern form of the pyrometric cone was developed by the German ceramics technologist Hermann Seger and first used to control the firing of porcelain wares at the Königliche Porzellanmanufaktur in Berlin, in 1886. Seger cones are still made by a small number of companies and the term is often used as a synonym for pyrometric cones.
Holdcroft Bars were developed in 1898 by Holdcroft & Co.
Bullers rings have been in continuous production for over 80 years, and are currently in use in over 45 countries. The manufacturers, Taylor Tunnicliff Limited, were founded in 1867.
The Standard Pyrometric Cone Company was founded by Edward J. Orton, Jr. in 1896.
PTCR rings were originally called "Phillips Temperature Control Rings" and developed by Phillips Electronics in Uden, Netherlands. The plant is now owned by Ferro and moved to its current location in St Dizier France in 2010.