Maria Ronneberger, PR Manager Voith Paper
The 500th shoe press is a Tandem NipcoFlex which will be part of the new board machine that Voith is delivering to the Indian paper manufacturer Tamil Nadu Newsprint and Paper Ltd. The board machine will start up in 2015 and is designed for a wire width of 4,300 mm and a speed of 600 m/min. A very high dewatering capacity is available with the two Tandem NipcoFlex shoe presses. Voith actually sold its 400th shoe press in 2010 to the Indian paper manufacturer; the latter uses a total of six NipcoFlex shoe presses from Voith, which demonstrates how convinced it is by this technology.
A FOUNDATION FOR SUCCESS.
In 1984 the first shoe press from Voith went into operation in Austria, still under the name of FlexoNip at that time. Since then the technology has been not only renamed but also constantly further developed for all grades. NipcoFlex shoe presses are used both for board and packaging paper as well as for graphic paper and tissue, likewise in pulp drying machines. This technology is also used in shoe calenders.
The innovation of the shoe press is that a concave formed press shoe presses the paper web and felt against a roll. The nip is thus substantially larger – clearly better dewatering can take place in this way without higher pressure. That saves energy for additional drying input. On the other hand, the paper is also dewatered in a substantially gentler fashion, volume is retained and the highest quality is ensured.
NIPCOFLEX T – EFFICIENT TISSUE PRODUCTION.
In 1999, Voith first brought its shoe press technology for tissue production to the market. With this technology, the focus was mainly on the product features of volume and softness, giving it a quality advantage over standard dry crepe machines. The NipcoFlex T is now the latest development in a new generation of shoe presses. The motivations for further development were the pursuit of energy conservation, efficiency and of course the question: how can fiber use be minimized. The answers led to the development of the NipcoFlex T shoe press for tissue production.
The press nip of a tissue machine is fundamentally different from a conventional nip of a paper machine, since the Yankee cylinder is not a counter roll in the usual sense. A shoe press for a tissue machine thus has to be configured very flexibly over its width. Only in this way can a uniform linear force be created in the press nip so as to obtain a homogeneous CD moisture profile.
In 2010, the first NipcoFlex T was put into operation at the Northern Tissue Group in Lancaster, UK. In comparison with conventional press rolls, the dry content after the press is up to 5% higher with NipcoFlex T technology. That means that up to 20% of thermal energy can be saved.
The NipcoFlex T shoe press has a substantially simpler design than the previous generation. With two rubber bellows as pressing devices instead of several pistons along the entire machine width, fewer control elements are required, which simplifies operation. The shoe press automatically adapts to the natural deformations of the Yankee cylinder and generally reduces deviations in the CD moisture profile. Setting the pressure profile gives the possibility of obtaining more bulkiness or more dryness after the press in all tissue grades.
According to Rogerio Berardi, responsible for Global Tissue Product Management at Voith, the NipcoFlex T press was developed in order to ensure more stability, leading to an increased production output. “The second generation of the NipcoFlex T shoe press has proven its significance for our business development and is very well accepted by the market,” reports Berardi.
ADVANTAGES OF NIPCOFLEX T.
• 5% more dry content after the press with the same paper quality in comparison to other technologies
• Up to 20% higher production or savings of thermal energy
• Very uniform CD moisture profiles
• High level of efficiency for the system thanks to the easy change between bulk and dryness
TISSUE MANUFACTURERS ARE CONVINCED.
Since 2010 Voith already sold 16 NipcoFlex T shoe presses to tissue makers all over the world. The shoe presses are suitable for machines with a width of 2,800 to 5,600 mm and running with an operating speed between 1,200 to 2,000 m/min.
As one example, PT Sun Paper Source in Sukoanyar, Indonesia, recently put a new VTM 1 tissue machine from Voith successfully into operation. The operating speed of 1,600 m/min was reached three days after start-up. It is the first machine worldwide in which a NipcoFlex T shoe press was combined with a steel Yankee cylinder and a high-performance steam-heated hood. With the combination of shoe press, steel Yankee cylinder and high-performance hood, the VTM 1 from Voith has a very energy-efficient design. With this project, Voith has succeeded in further strengthening its position with innovative technologies for the tissue sector.