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De-ashing – SpeedWasher and RotoWash

Removal of inorganic material (filler and coating pigments) from fiber suspensions

The SpeedWasher SW: efficient and selective de-ashing

The ANDRITZ SpeedWasher removes inorganic material (filler and coating pigments) from a fiber suspension. The machine has an endless wire running at a speed of up to 1,000 m/min. The de-ashing effect comes from the one-sided dewatering of the fiber suspension between a forming roll and the wire. Pigments are enriched in the filtrate, which is de-aerated and discharged through spin tubes. The thickened, de-ashed stock builds a fiber mat, is doctored off the rolls, and is transported out of the machine with a screw conveyor. Machine configurations with one or two headboxes are available.

Benefits of de-ashing with SpeedWasher SW

  • High de-ashing capability and discharge consistency due to strong thickening effect
  • Low energy demand
  • Cantilever design for fast and easy change of the endless wire
  • Headboxes with cross-flow distributors and diffuser inserts for optimum pulp distribution and uniform dewatering
  • Efficient wire cleaning via high-pressure needle jet nozzles
  • Oscillating doctors for gentle pulp take-off from forming rolls
  • Closed design with vapor hood and splash guards

RotoWash RW: compact/flexible de-ashing with efficient fiber recovery

RotoWash RW is a multi-use machine ideal for de-ashing pulp and recovering fiber from filtrates and sludges. The RotoWash can also be used as a protection filter for shower nozzles and similar devices. Its design is based upon a well-proven pressure screen with electron-beamed hole basket and optimized rotor and tip design.

Benefits of de-ashing with RotoWash RW

  • High yield and stock quality due to selective fractionation of organic and inorganic material
  • Efficient fiber recovery, low solids content in effluent water
  • Closed system and low maintenance operation
  • Easily adaptable to specific process conditions through simple modifications of operating parameters
SpeedWasher SW

SpeedWasher SW

RotoWash RW

RotoWash RW

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