Web treatment device e.g. doctor blade - has support bar carrying number of carriages acting on blade supports to move them perpendicularly to their movement

摘要

Web treatment device has a support bar extending transversely of the moving web for guiding of a number of spaced carriages each of which is associated with a setting member which is arranged to move transversely w.r.t. its carriage on movement of the latter. Device is provided with a signal transducer which is effective to induce displacement of a carriage in response to the evaluation of signals at a predetermined time across the width of the web. Treatment device may take the form of a web coating doctor blade which is adjusted relative to the nip, or the device may form part of the throat of the paper stock head box in paper making machines; or support water spraying nozzles for spraying webs during a processing step; or plastics extrusion nozzle with variable slit width; or pneumatic doctor blade or calender cylinder nip adjusting means. Adjustment of device relative to the transverse direction of the web can be effected automatically and quickly from the set of values sensed across the web width.