How to deal with unevenness on both sides of the paper
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The paper is not evenly distributed, mainly because of the uneven flow rate and uniformity of the slurry in the headbox, the uneven velocity of the overflow slurry and the uneven flow of white water on both sides of the mesh. Generally, the flow rate of the wall of the mesh is slightly behind the central part, especially when the wall of the mesh is rough, and the width of the door is wide; in addition, the inlet of the slurry is not in the center, and the structure of the headbox is unreasonable. The following measures can be taken in the production:
(1) Adding water to dilute the concentration of the local paper stock to reduce the tendency of the local pulp to be large.
(2) The movable curved plate mesh groove can adjust the distance between the movable curved plate and the two sides of the net. This distance must be adjusted properly, which has a great influence on the formation of the paper. If the distance is too close, the pulp speed will exceed the speed of the net, causing the paper to appear thin; too far uniformity is not good, the paper sheet is flaky or flowery. Generally, the side of the paper web is quantitatively large, and the distance between the curved plate and the net cage is adjusted closer; otherwise, the width is adjusted.
(3) Adjusting the distance between the rubber skirt on both sides of the spray plate, that is, raising or lowering one side thereof to achieve the purpose of adjusting the thickness and uniformity of the paper, and also cutting the rubber skirt into a circular arc shape to overcome the middle of the paper sheet. The disadvantages of thick double-sided books.
(4) The lifting adjustment plate (grid knife) on the headbox can adjust the unilateral basis of the paper. The adjustment plate is raised. The flow rate of the paper liquid is slowed down, and the flushing effect is reduced. In other places, the paper liquid increases the sizing, that is, the quantitative amount in the section increases.