Abstract:
Multi-ply web forming stock jets directed through a slice from a single headbox into a forming zone between converging forming surfaces in a papermaking machine are maintained separated for a sufficient interval after leaving the slice opening to permit drainage and partial ply formation of the stock delivered by one of the stock jets to one of the forming surfaces before the stock in a second of the stock jets joins in fiber felting laminar relation with the contiguous surface of the partially formed ply. Flexible divider sheet members divide the slice chamber of a headbox into separate flow passages aligned respectively with different ones of headbox subchambers to receive streams of the stock from the respective subchambers and maintain the streams separated, and the flexible members extend a substantial distance out of the slice opening in the direction of flow of the stock jets to maintain stock jets separated for a sufficient interval after leaving the slice opening.
Abstract:
A method and mechanism for compensating for pressure fluctuations in a paper machine stock flow system for conducting stock from a supply pump to a slice opening including providing a flexible diaphragm as one wall of the stock conduit with the diaphragm dampening pressure variations and being supported on its opposite side by air in an air chamber divided into compartments with a support compartment immediately opposite the diaphragm and a supply compartment behind the support compartment and the compartments divided by an attenuator wall. Air is supplied continuously at a reference pressure to the supply compartment, and a relief valve is positioned in the support compartment with the port opened or closed by movement of the diaphragm so that air is bled from the support compartment as the diaphragm moves toward the stock conduit with a drop of pressure therein. In another form, the structure includes a diaphragm wall between a distribution chamber of a headbox and an air chamber with a valve controlling the release of pressure from the air chamber and controlled by the position of the diaphragm.
Abstract:
Cable means are provided for controlling internal tension in web rolls during winding thereof onto cores with the aid of winding drums. According to the method of utilizing cable means for this purpose, the web rolls are partially wound between the winding drums and a rider roll, the rider roll being backed off from the web rolls after they have attained partial diameter, and during continuation of the winding of the web rolls to full diameter the load-relieving lift is applied to the web rolls through their cores by the cable means.