Crown
Crown turns up in 2 fields: refractories, printing. Here is what it means to the people in each one.
Crown in refractories
Arched refractory roof of a glass furnace or other large furnace, often built of silica brick.
The sprung arch that roofs a glass melting tank, a reheat furnace or a regenerator chamber. Glass furnace crowns are usually silica brick: it carries load almost to its melting point, and silica that drips into the melt dissolves without leaving defects. Oxy-fuel furnaces often use alumina or AZS instead, because alkali vapors attack silica and eat channels called rat holes. Crown temperature limits how hard the furnace can be fired.
"Crown is at 1590, that's the limit for silica, back off the burners on port 3."
Crown in printing
A traditional British paper size measuring 20 by 15 inches.
A historic British paper dimension measuring 20 by 15 inches in the broadsheet format. It forms the basis for a family of standard book sizes when folded, such as crown octavo or crown quarto. The name originates from the watermark of a crown used by early papermakers to identify this specific sheet size.
"We need a pallet of crown stock for the poetry run, since they want the traditional octavo trim."