Control of fibre orientation on wire of paper-making machine - by inducing flow pattern variations in region between feed and suction box

摘要

The fibre orientation on the wire of a paper making machine is controlled by altering the flow in the region between the feed and the suction box. The flow direction can be altered by changing the surface profile of the forming board or by having openings in the forming board through which water can be drawn off or air, steam, water or a suspension can be supplied. Alternatively steerable guide vanes can be used. Pref. the surface of the forming board consists of flexible material and has movable elements which can be raised or lowered to alter the profile and hence the flow pattern. Alternatively, the forming board has perforations which are connected via control valves to a pump so that water can be drawn off locally. USE/ADVANTAGE - The method improves the fibre orientation which may have been disturbed by flow control devices in the feed.