18 INDUSTRY NEWSXERIUM 3


felts running for five to six days on the paper machine achieve a pore-size-distribution at a major level of 30-40µm. New press felts equipped with Booster Technology are at the same pore-size- distribution level as standard press felts running for five to six days (as shown in Figure 2) To summarise, press felts equipped with this technology offer immediate dewatering at full machine speed during start-up by providing a 20 per cent reduction in pore-size-level and start-up optimised pore-size- distribution with no limitation in lifetime.


QS Technology The QS (quick saturation) Technology focuses on achieving a perfect water house hold within the press felt structure. Demands on press felts are not only perfect sheet transfer, good self-cleaning and immediate dewatering, but also providing optimised water handling ability. To achieve immediate dewatering, the key is to retain a certain amount of water within the press felt structure… the key is water retention ability. Specifically-developed


hydrophilic materials have been integrated into the base fabric structure of the felt to guarantee that the optimum amount of water is retained and that the felt is perfectly conditioned and saturated ahead of the nip. This results in immediate, continuous nip dewatering for the entire running life of the felt. Guiding suction rolls, suction


pressure rolls and uhleboxes are influencing the water balance of press felts. The applied vacuum removes a certain amount of water from the press felt, thus reducing sufficient felt saturation for optimum nip dewatering.


November/December 2014


Pulp Paper & Logistics


Figure 5


Figure 3 shows the water retention ability of a standard press felt compared to a press felt equipped with QS-Technology. Despite applied vacuum, the QS technology press felt can retain a 20 per cent higher amount of water within its structure and therefore provide a much faster saturation.


Field results Both technologies have delivered very positive results for Xerium’s customers, and they fully meet the increasingly challenging demands of modern paper machines and even often exceed the expectations. For example, a Trivent Press


concept producing LWC, MWC at 1,400 metres per minute was running trials with the target of nip dewatering and energy savings by running the paper machine without uhleboxes. To meet the customers’


requirements a trial plan was generated where press felt designs were changed to QS


Technology, respectively Booster Technology, to achieve immediate start up with full nip dewatering and full machine speed. The trial results exceeded


customers’ expectations. The standard applied vacuum at the uhleboxes was reduced to zero. This enabled in a shutdown of a 350kW vacuum pump generating a significant amount of annual savings. In addition the drive load was reduced by about 20 per cent.


Considering the reduced amount


of fresh water consumption, which was formerly used for uhlebox lubrication and savings of annual maintenance costs, a cost reduction of nearly €450,000 per year was achieved. Besides energy savings,


two profitable effects were also documented. Firstly, nip dewatering improves the dryness content of the paper sheet, yielding in higher initial paper strength which resulted in lower draws and drastically reduced break rates. Secondly, due to nip


dewatering right from the start up and therefore with full machine speed a production increase was achieved. In total, the customer achieved annual overall savings of €900,000.


Conclusion Even though the expenditure on paper machine clothing accounts for a relatively small cost-per- ton of running a paper machine, its influence can be extremely beneficial in running a paper machine in a more cost efficient way. Every paper machine has its energy optimum and Xerium is the experienced partner in adding value to a paper making business. More information from Robert


Marchhart, Global Product Manager, PMC & Engineered Fabrics, Huyck.Wangner Austria GmbH, Huyckstraße 1, 2640 Gloggnitz, Austria. Tel: 43-2662- 410-101. Mobile: 43-664-8275416. Email: robert.marchhart@xerium- europe.com Website: www. xerium.com


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