At Sappi (Johannesburg, South Africa) operations in Kirkniemi, Finland, Voith (Hedenheim, Germany) has successfully converted the existing Hedemora disc filter in the stock preparation unit to the latest BaglessPlus filter technology.

As the number of discs could be reduced, the disc filter will be well prepared for future increased capacity. The rebuild has also substantially improved the performance of fiber material removal and reduced maintenance costs. Filtrate quality is now more stable due to no more leakage in filter plastic bags.

With the newly installed BaglessPlus disc filter sectors with knock-off nozzles, the number of sectors could be reduced from 18 to 16 discs. With full assembly, capacity increases of up to 30% can be achieved, when future upgrade of the production line is necessary. The conversion to BaglessPlus has allowed stable and good filtrate quality. This filtrate quality will remain constant over the entire service life of the sectors of more than 10 years. The BaglessPlus sectors are maintenance-free and do not suffer from any kind of leakage. Thanks to the consistent process conditions, the operation is more stable.

Impressed by the concept for the new filter technology with BaglessPlus, Sappi decided to also commission Voith to rebuild an Ahlström disc filter at its mill in Kirkniemi during this year’s scheduled summer shutdown.