A Paper Sheet Contactless Linear Speed Measurement

Abstract Web speed and draw measurements on an industrial paper machine are generally obtained by means of rotating speeds. It is now possible to measure true linear speed, without contact by several techniques which are briefly reviewed. The principle of speed measurement by correlation of two optical signals is given. An instrument based on the autocorrelation of a single signal laser transducer is described as well as its signal processing specific unit. Results are presented, the main features of the instrument are discussed. Possible applications in the paper industry and on other materials are listed, having in mind process control.