The aim of this process is to reach a desired stock brightness by removing ink. For this goal, usually two flotation and thickening steps are required. During flotation, ash is lost to certain degree. However, to produce a consistent paper quality, the ash content needs to be constant. Uncontrolled flotation would result in a higher consumption of ash to compensate the loss, higher costs for the disposal of the ash removed by flotation and more wastepaper to receive the same amount of final product. Using Berthold’s density measurement solution to determine the ash content in the pulp, the deinking performance will be optimized by keeping the ash content constant.

Customer Benefit

  • Saves filler material
  • Keeps the ash content constant
  • Saves energy
  • Maximum use of recycled wastepaper fibres


  • Inline density measurement
  • Concentration of ash content 
  • Unaffected by the hostile ambient conditions
  • High measurement stability and endurance



Density Measurement Brochure

Englisch | PDF | 1.6 MB

Solutions for pulp and paper production Brochure

English | PDF | 1.2 MB

Berthold's Measurement Solutions

LB 379 Inline Density Meter

Low energy compact density meter working with extremely low dose rates (comparable to x-rays)