Chip screening

We offer complete chip screening systems for both thickness screening and conventional screening:

  • Scalper screens
  • Disc screens
  • ScreenMaster™ thickness screens
  • ScreenMaster™ fines screens
  • Gyratory screens
  • Stone separators
  • Metal separators
  • Chip Improvers™
  • ChipMaster™ re-chippers
  • Laboratory classifiers

The purpose of chip screening is to form the optimum chip size distribution for pulping process. Modern mills typically use thickness screening process because this has a large influence on cooking results. Increased yield, decreased rejects, lower kappa number, lower alkali consumption and better pulp strength are just some of the benefits of properly controlling chip thickness.

Both mechanical and chemical pulping processes achieve benefits by fines removal and pin chip control. The elimination of fines from wood chips improves pulp strength and quality while simultaneously reducing chemical use.


Two fundamental performance objectives of a thickness screen are to provide high overthick removal efficiency and minimize the carryover of accept chips. The ScreenMaster™ thickness screen provides a superior solution to meet these process requirements. Effective chip flow agitation, high overthick removal efficiency and high selectivity are achieved using a special disc construction and a combination of three disc diameters. The proven screen construction offers low space requirement, low power demand and easy maintenance. Thanks to a special steel alloy and hard facing the wear of the discs is extremely low.


The patented ScreenMaster™ fines screen provides excellent fines and pins removal efficiency combined with minimal acceptable fiber loss. Because there are no overlapping parts in the adjacent screen rolls, fiber-destroying crushing action does not appear between the rolls. The roll diameter is large enough to enable powerful chip flow agitation which is prerequisite to effecive fines removal at high infeed capacity. The screen is equipped with a variable speed controller, which allows adjusting the fines removal efficiency and selectivity while the screen is operating.

Chip Improver™ & ChipMaster™

In chemical pulping the most favourable way of treating overthick chips is to use the Chip Improver™. The pulpability of overthick chips is improved efficiently by a gentle destructuring action producing only a minimum of fines and pins. The simple construction with shaft-mounted drives needs very little maintenance.

For mechanical pulping the ChipMaster™ series re-chippers offer a rugged machine for oversize chip treatment utilizing modern chipping geometry.