Nash supplies a flexible vacuum system for paper machine

GDNash-PR-Zellstoff-Poels_deZellstoff Pöls, in Austria, is one of the largest manufacturer of high quality, chlorine-free bleached long-fibre sulphate pulp in Central and South Eastern Europe. For the new PM2 paper machine, Nash is supplying the vacuum system for dewatering in the wire section and the press section. The Zellstoff Pöls PM2 focuses on “machine glazed” papers (a paper with very high strength), and incorporates the production of paper basis weights between 28 and 120 g/m². This wide product spectrum places high demands on the flexibility of the vacuum system, as the method of drying has to adapt to each paper grade. The major challenge was adapting the vacuum at the various suction points for each specified paper weight and the required drying needs. This was accomplished through the use of frequency converters that allowed for “fine adjustment” of the speed and the vacuum level to meet the specific requirements of the paper grade produced.

In a first step, the required number and capacity of the liquid ring vacuum pumps were calculated for ensuring the requisite operational flexibility of the vacuum system. It had to be taken into consideration that strongly fluctuating vacuum levels are often applied at the various suction points in accordance with the grammage to be produced. All Nash pumps are driven with a frequency converter for “fine adjustment” purposes. In this way, the motor and pump speed – and thus the vacuum level of the pump – can be exactly controlled and precisely adapted to the specific requirement.

The project covers a scope of supply of five 2BE4 pumps of various sizes, all operated with frequency converters. The pumps will be provided in standard cast iron material construction with polyisoprene coating.

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