Metso Paper offers next-generation tissue pressing technology
Metso Paper has recently patented and launched a new press design for tissue machines, the Advantage ViscoNip technology.
The new Advantage ViscoNip press design gives tissue makers an incredibly versatile new tool for lowering the energy consumption as well as increasing the bulk. The benefits of the new technology as compared to either a suction press of a shoe press include the following:
· Lower energy consumption · Higher dryness · Improved bulk · Better runnability · Smoother operation
Energy savings are the biggest benefit of the ViscoNip press, with the higher dryness showing significant energy savings for a new installation. With the high energy prices of the present, energy costs have become the most vital challenge for tissue makers, and the ViscoNip technology can certainly help.
Better bulk is also a key advantage as the new design gives higher bulk than conventional pressing at a given sheet dryness. Thus papermakers can get a bulk similar to that of a shoe press construction but without problems in runnability, felts or belts that the industry has experienced with the hard shoe pressed against the felt and the Yankee dryer shell. The flexible nature of the pillows is the key to getting a softer, yet more efficient pressing action while still maintaining the bulk. This flexibility gives tissue makers much greater freedom in the choice between dryness and bulk.
An added benefit that has been proven in pilot trials with the ViscoNip press is a much better dryness profile across the sheet. So not only is runnability through the press improved but also runnability through the rest of the machine and the converting as the final product quality is also enhanced by the flatter dryness profile.
<b>The new 'pillow' design for flexible pressure distribution</b>
The new arrangement is designated as a 'Pillow Press' due to the fact that the working pressure against the Yankee cylinder is effectively delivered by several separate pillows. These pillows, positioned parallel to each other in the cross-machine direction, are hydraulically loaded to achieve linear loads of 80-160 kN/m, or even higher. Of course the Yankee shell must be able to take the load but the pillow design allows incredible flexibility in distributing the load.
Since the pillows are made of flexible material and are hydraulically loaded, a uniform load is delivered to the sheet, independent of the running conditions or any deformation of the Yankee. This self-compensating profiling ability of the new pillow technology offers enormous benefits as compared to other tissue press designs.
The ViscoNip press is suitable for either a new installation or for a rebuild in which a suction press or a shoe press can be replaced with the new pillow press technology.
For more information, please contact: Jan Erikson, Vice President Sales, Metso Paper, Tissue Business Line Tel. +46 54 17 14 90, mobile: +46 70 517 14 90
Ingvar Klerelid Vice President Technology, Metso Paper, Tissue Business Line Tel. +46 54 17 24 23, mobile: +46 70 317 14 13