Key Benefits

  • Protect downstream equipment
  • Maintain product quality
  • Reduce costs

Improve your pulping process with cost-effective impurity removal

Our KREBS® Pulp Cleaner Cyclones, also known as “high-density stock cleaners,” separate heavy solid contaminants from your paper pulp in order to protect your downstream equipment and maintain product quality.

The solid design behind these highly efficient cyclones allow them to withstand corrosion, high temperatures and heavy loads of abrasive materials, such as glass, staples, wire and other debris. Our high-density stock cleaners can be used in primary stock, as well as severely abrasive and corrosive secondary stock processes.


Continuous rejects cleaners remove fine sand from paper pulp – typically in multiple stages. Our Intermittent Rejects Cleaners collect larger debris and discharge it intermittently. The basis for both types of pulp cleaners is the renowned KREBS Cyclone. Continuous rejects cleaners are hydrocyclones with conventional apexes. These may be connected to a rejects header or rejects trough, if multiple cleaners are being operated in parallel. Intermittent rejects cleaners are hydrocyclones with the addition of a grit pot and isolation valves. Intermittent rejects cleaners discharge the contents of the grit pot periodically, without shutting down the cleaner.


The applications for centrifugal cleaners in the pulp and paper industry can be divided into two major categories: chemical (or virgin) pulp cleaning and recycled fibre cleaning.


Chemical pulp

In applications where softwood and hardwood species are chemically digested to produce paper pulp, the product is mostly Kraft (sulfate) pulp.


Protect your secondary knotters from rocks and gravel with our intermittent rejects cleaners. These hydrocyclones also are effective in protecting screening equipment.


For chemical pulp applications, continuous rejects cleaners in two or three stages efficiently perform fine sand removal in the screen room.


Recycled fibre

Recycled paper mills face their own unique challenges, as feed stock varies from old corrugated cardboard (OCC), old newsprint (ONP), mixed office waste (MOW) and ledger paper (LED) to magazines and computer paper. Debris within these feed stocks include baling wire, packing bands, box staples, paper staples, broken glass, gravel and sand, and they may represent a significant amount of the feed.


Our Intermittent Rejects Cleaners, installed following the pulper, remove these contaminants prior to screening, which greatly increases the wear life of your screen baskets.


This is a demanding application that requires a heavy-duty cleaner and valves.

Protect your process with our pulp cleaner cyclones

Protect downstream equipment

Hydrocyclones are effective in cleaning pulp of debris, protecting such downstream machines as secondary knotters and screening equipment.

By effectively removing the solid contaminants from your product prior to downstream equipment, these cyclones work to protect your capital investment from abrasion, erosion, corrosion and ultimate failure. Using our gMAX Cyclone technology, we can deliver high capacity in a small footprint, high g-force separation and high efficiency.

Maintain product quality
When debris remains in your paper pulp slurry, it not only can damage downstream equipment, but clearly it affects the quality of your paper products.
Reduce costs
KREBS hydrocyclones are compact, reducing capital and installations costs. They provide efficient separation with relatively low power consumption, and they are simple to operate, as they have no moving parts. Sectionalised construction reduces your maintenance costs. And, with a number of options for wear liners, our cyclones are highly wear-resistant.

High-density stock cleaners designed for process improvement

We offer pulp and paper cleaners to fit your specific application, including:

Continuous rejects cleaner systems that are available with feed, accepts, and rejects headers and isolation valves. These typically are designed in multiple stages to reduce the amount of fiber lost with the rejects.


Intermittent rejects cleaners, equipped with grit pots, valves, and timers to periodically dump the separated contaminants at pre-set intervals.


Our systems will separate contaminants from pulp streams at consistencies of 0.5% to 4.5%.


Applications include gravel and sand removal from softwood and hardwood pulp, as well as baling wire, packing band, box staple, paper staple, broken glass, sand and grit removal from recycled paper (i.e. OCC, ONP, MOW).

Additional features

  • Wide range of cleaner sizes available
  • Sectionalised construction for lower cost maintenance
  • Vulcanised elastomer wear lining in the upper sections of the cleaner for high pressure units
  • Epoxy paint system as standard for corrosion resistance
  • Replaceable wear liners, available in nitrile and other synthetic elastomers
  • Nihard, and ceramic liners used in lower cleaner sections, which are exposed to the highest wear
  • Heavy-duty, reliable knife gate or ball valves available for grit pot (intermittent rejects) operation

KREBS® Quick Release™ system for pump rebuilds

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