Fenchel Expansion Meter - OpTest

This machine is designed to measure expansion of a paper sheet or paperboard sheet by immersing the paper in water. The specimen is fixed with the upper and lower clamps. From the upper clamp, a weight is suspended via a pulley, with the thread linked to a dial gauge. With this weight, a certain amount of tension is given to the specimen that is in the water for a certain span of time. Expansion of the specimen is indicated on the gauge.

There are two pipes on the upper lid, enabling to monitor dimensional stability of a specimen with changing relative humidity, under the circulation of the air of a constant humidity in the container.