Andersson Stair Screen ASS

  • Andersson Stair Screen ASS is the worlds strongest “traditional” step screen for deep short channels.
  • Several times stronger frame, bars, drive unit, transmission, bearings than others.
  • Modern easy maintenance construction from robust stainless high quality materials.
  • Totally self cleaning. No spraying or brushes.
  • Totally self aligned bars without rakes.
  • Easy replaceable strong bars and spacers.
  • Flexible mounting angle 45-55 degree.
  • Easy adapted hinged support legs enables quick pivoting out of the channel for service.
  • Enclosed, safe & hygienic with easy to open access doors.

Andersson Stair Screen ASS is a mechanical ”moving bar” fine screen that separates debrie and rubbish from water. Moving bar step type fine screens has unique capabilities: A 1-6mm Stair Screen can replace a 10-30mm coarse screen
in an existing open channel while maintaining the same low headloss, without any need for pre screening. Stair Screen ASS is totally self cleaning without flushing or brushes. This gives unrivalled capacity, result and total economy.

We recommend ASS in for WWTP headworks with short length channels. And also for channels with shallow waterlevels <800-1000mm or for heavily concentrated applications such as septic sludge screening where a higher solids conveying capacity is needed. We generally recommend 3mm bar spacing for ASS. It is produced with up to 6mm bar spacing but thats generally a waste of separation and capacity capabilities since its rare that a 3mm ASS does not fit even the severest existing hydraulics and headworks situations. However, at WWTP headworks where the waterlevels are >800-1000mm and the channel length allows to use a 1-2mm 45 deg Progressive Stair Screen PSS we advice to do so rather than a 3mm ASS.


  • Discharge height 700-7000mm
  • Width 200-2500mm
  • Bar spacing 1, 2, 3, 6mm
  • Capacity 10-10000l/s


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