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Pyrometric devices gauge heatwork (the combined effect of both time and temperature) 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 :Are flat, hollow centred rings whose contraction is proportional to the heat work experienced. A micrometer or gauge measures the fired ring, with the difference being an arbitrary number that is used to describe the firing regime experienced. Various grades of ring, each of slightly different compositions, are available to cover all firing conditions and temperature equivalents likely to be encountered. Examples of pyrometric rings include Bullers Rings, PTCR Rings and Thermorings.〔http://www.schwendler.de/english/tempindi.htm〕〔http://www.ferro.com/NR/rdonlyres/74F71FE1-407D-4A48-B386-24E90542A3FA/0/IS04_e_PTCR.pdf〕 ; Bars :Are square, sectioned bars held horizontally across two fixed distance supports. During firing the softening of the material results in sagging at the centre. Pyrometric Bars have found popularity in Kiln Sitters, which uses the described deformation to act as a triggering element, thus turning off the kiln at a desired point of maturity. Examples of pyrometric Bars include ''Holdcroft Bars'' and "Orton Bars". ; Cones :Are slender, three sided pyramids made from a range of compositions each with a reference number corresponding to a certain heat work. Rather than shrink as rings do, a cone's tip will bend forward to the same level as the base at the time of maturity. Other deformation of a cone, such as bloating, cracking, or bending backward, can be appropriately interpreted to troubleshoot activity inside the kiln. ; Discs :Are calibrated ceramic disc-shaped devices. Examples include Bullers Process Control Discs and TempCHEKS.〔http://www.mantectechnicalceramics.com/products-services/kiln-furnace-products/temperature-control/bullers-process-control-discs-bpcds〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Pyrometric device」の詳細全文を読む スポンサード リンク
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