WiPa Pre-wash screw Type EWS / DEWS

The WiPa pre-wash screws are used to wash, rinse, soak and separate sinking contamination substances such as stones, sand or glass.

The process

The material is fed into a pre-wash tank at the bottom end of the pre-wash screw and pushed under water by paddle rollers. Subsequently, 1 - 2 screw conveyors move the material to the top. During transport, the material moves a lot, which means that contamination substances such as stone, sand, glass and metals can easily sink down. Additionally, the adhesions on the plastic material are being soaked in order to be able to detach them more easily.

Different discharge systems can be used, depending on the type of contamination. Simple, small contamination substances such as stone or glass are discharged over a time-controlled valve system. For larger or long contamination substances, such as wire, or for larger contamination volumes, drag chain conveyors are used for discharge.


  • Separation of impurities from the product
  • Soaking the contaminating substances on the product
  • Screw and housing of stainless steel 1.4301
  • Drive per screw
  • Various discharge systems for contaminating substances
  • High discharge rates