Fine Material Screw Washer (Sand Screw Washer)

The fine material screw washer (sand screw washer) is a washing unit that scrubs sand carrying soil, dust and foreign particles with rotating spirals (screws). It accepts 0-50 mm feed and runs at 50-250 tph. General Makina builds its screw washers to CE and ISO 9001 certification.

How it works

A screw rotates inside an inclined tub, scrubbing fine sand along the tub floor toward the discharge end while light water carrying clay and silt overflows at the top.

• The water-and-material slurry enters at the lower end of the tub.
• The spiral scrubs fine sand and conveys it up to the discharge end.
• Clay- and silt-laden light water overflows the weir and is removed.
• Clean, partly dewatered sand is discharged.

Water demand is of the order of ~190 L/min per tph of silt; screw speed is set by the proportion of fine material.

Technical specifications

Feed 0-50 mm, capacity 50-250 tph. Single = economical; twin = higher capacity and better scrubbing. Certification: CE + ISO 9001.

Moisture and the dewatering chain

Screw-washer discharge moisture is typically 15-30%. For a drier, directly stockpilable product the chain is extended: screw washer → hydrocyclone → dewatering screen brings moisture down to 8-20%. The hydrocyclone recovers fine sand around d50 ~45-150 µm (target ~150 µm in aggregate). Clay is measured by Methylene Blue Value (MBV) or Sand Equivalent (SE).

Where it fits

Applications: river and quarry sand-and-gravel, fine scrubbing of ore, clean aggregate for concrete batching and sand recovery. This machine excels at scrubbing fine sand (0-50 mm) carrying a light clay load; when the feed is low-clay and water saving comes first, move to the bucket wheel, and when coarse stone or heavy plastic clay is involved, move to the log-shaft washer.

Turnkey washing line

General Makina combines the screw washer with the hydrocyclone-dewatering group, GNR YM washing-screening plants and a concrete batching plant in one project; crushing, screening and washing are engineered under one roof. A single point of contact, a matched spare-parts chain and on-site commissioning support come together.