ST Macchine designs and supplies new stock prep and approach flow
By Jarshire, Jun 12 2019 08:47AM
At the end of November 2017 ST Macchine was awarded a significant order for the turnkey supply of a new approach flow and new stock preparation systems for PM1 at IPZS (Istituto Poligrafico & Zecca dello Stato) who were due to commence production of specialty watermarked papers in June 2018.
Both projects required high specification technology and know-how to deal with very long fibres, such as cotton, cotton linters & softwood, and the refining process needed to be engineered for different mixtures of these raw materials. Consequently, various refining solutions were considered.
For the continuous refining process ST Macchine supplied four new conical refiners each comprising different components.
Due to the freeness (fibre drainage rate) and, in particular, for the approach flow, the engineering of the piping required advanced technology to avoid any internal deposit of fibres and blockage of the screens in the short circuit.
A) The existing stock preparation system was revamped by the installation of:
Main Line for raw material treatment:
A low density pulper 14 c.m. for the treatment of softwood, cotton linters & cotton fibre
An automatic discharge HD cleaner 500 lpm
Four conical refiners “Conic Flow” size 1 in the new design
A new chest for the refining process
New line for wet strength waste comprising:
An HD pulper 8 c.m.
A pulper screen PSC 10
An HD cleaner 800 lpm
A deflaker type DST 01
B) For the approach flow the following equipment was supplied:
New chests for the storage of the waste water from the new Voith short former & master vat
A stand pipe for the short former & master vat
A new LD cleaning system
An approach flow screen type SPC 20 ahead of the PM for the master vat
An approach flow screen type SPC 04 ahead of the PM for the short former
An approach flow screen type SPC 20 ahead of the PM for rejects of both main screens
ABB & Siemens equipment was chosen to control the processes of both systems.
ST Macchine design-enginereed all the piping specifications in 3D within 45 days of receipt of the order and completed the whole project in four months. Both systems were successfully started up in June 2018 to the customer’s complete satisfaction and, following approval from BCE, the mill commenced producing new, high-value watermarked papers early in 2019.