In Pottery, a Kiln Sitter is a mechanical device used to shut off the kiln at the proper time.
A Kiln-Sitter is a mechanical devise that shuts off the kiln off at the correct time. A small pyrometric cone that is placed in the Kiln-Sitter will bend it when it reaches the appropriate amount of heat. This causes a lever in the kiln sitter to drop, and the kiln-sitter will turn the kiln off. It's simple and works well. Before the advent of computerized electronic controllers this was the common device used to control the heating in the kiln.