Closed pressure screens are designed for screening nodes in the stock preparation lines. Their featuring properties are high performance, good screening efficiency, minimal fibre quantities lost in rejects, low demands on erection, maintenance and servicing.

In the stock preparation lines processing waste paper screens work in primary coarse screening nodes with bored screens, in final fine screening nodes they remove the finest particles, plastic foils and stickies from stock on slotted screens. They are also utilised to screen stock by finer length – to fractionate.

In pulp mills they are used in final screening stages to finely screen bleached and unbleached chemical pulp. They catch small knots, bark and non-fibrous admixtures. In groundwood plants the are used in final screening stages to finely screen matchwood.

Design

The screen design is a compact closed one with a vertical screen wiped from inside by a turning rotor. An inflow duct and ducts discharging light and heavy impurities are connected tangentially. The accept outflow duct is of a radial type. The screens are equipped with special lids (type L) for effective stock deaeration and and for screening the lightest impurities.

Main parts

• Machine body (1) with vertical cylindrical screen (2)
• Inflow part (3) with heavy trash separator
• Outflow part (4)
• Lid (5)
• Rotor (6)
• Frame with belt drive (7)
• Electric motor (8)

Material

• All parts coming to contact with the stock are made of stainless steel
• Other machine parts are made of common coated structural materials