Screw Washers

Screw Washers are available in two basic designs for differing functions: Coarse Material Screw Washers and Fine Material Screw Washers. 

Coarse Material Screw Washers are widely used for scrubbing gravel, stone and hard ores being nominally larger than 5mm or 4 mesh that have water soluble mud or clay contaminates that cannot be removed by a wet washing vibrating screen alone.

Fine Material Screw Washers are widely used for washing, dewatering and classifying solids nominally being as large as 10mm or 3/8”and smaller.

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Why McLanahan Screw Washers

McLanahan has extensive experience in washing a wide range of materials that started in 1891 when Samuel Calvin McLanahan was granted a patent for an ore washing steel shafted machine he called the Log Washer. As a manufacturer having the widest range of washing equipment, McLanahan can offer the correct solution, not an option of only one or two machines others may have. This combination of experience and choices, along with our global staff’s process application knowledge, makes McLanahan the best choice for your material washing needs.

McLanahan offers washing equipment that has capacities ranging from 20 to 8,000 tph. For most any ore, rock or sand washing problem you have, McLanahan has a solution that offers less downtime and maintenance and more clean product for your highest profitability.

How Screw Washers Work

Depending on the duty requirements, solids enter in a controlled size at one end of a rotating spiral screw shaft that is submerged in a pool of water caused by the installed inclination of the machine. Water and liberated fine solids overflow a weir system in a controlled manner for further processing or disposal. Coarse solids that are retained settle in the tub containing the rotating spiral screw shaft, which conveys the solids up the angled slope, out of the pool area and dewaters them to allow transport, typically by a belt conveyor, for stockpiling or further processing. Screw shaft diameter and rotational speed primarily are factors in determining the capacity of the turning shaft.

Popular Applications for Screw Washers

Fine Material Screw Washers can be used for washing most any hard ore, rock, stone or sand being minus 10mm or less having a specific gravity of 2.5 or higher and having water soluble clays or silts that need removed. The resulting dewatering allows most solids to be stockpiled by a belt conveyor up to 16 degrees. Fine Material Screw Washers are also used for processing solar evaporated salt solids, removing fine impurities.

Coarse Material Screw Washers can be used for washing a lot of + 5mm or 4 mesh rock and ore solids having water soluble contaminants. While some manufacturers only offer Log Washers recommended for rock and ore having tough, plastic, fine-grained, sticky clay contaminants, many times a lower-costing, lower kilowatt-powered Coarse Material Screw Washer can be used. When crushed construction and demolition feeds contain non-water logged wood and vegetation, a Coarse Material Washer can be used with uplifting rising current water to remove this debris.

Benefits of McLanahan Screw Washers

  • Low-cost and lowest kW (HP) power choice washing over many other options
  • McLanahan Twin-Seal Pak submerged rear bearing assembly incorporates Caterpillar Duo-Cone® seals that keep water and even the smallest particles from reaching the bearing
  • Shafts flanged at each end to facilitate maintenance are straightened to ensure maximum wear life
  • High brinnell, abrasion-resistant white iron wear shoes and or paddles that provide long wear life
  • Extended length wear shoes to protect more of the spiral flights near to the pipe shaft
  • Multiple rising current water injection points for better fines removal
  • Off-the-shelf reducers for quick local procurement or factory support if necessary
  • Large pool area for fine solids retention on Fine Material Screw Washers
  • Longer screw shafts for better dewatering
  • Quick and easy weir adjustment

Screw Washers Models

Mc Lanahan Coarse Material Screw Washer Coarse Material Screw Washers
Mc Lanahan Fine Material Screw Washer Fine Material Screw Washers

Frequently Asked Questions

How much does it cost?

McLanahan Screw Washers can be a low-cost, low kilowatt power option in comparison to other equipment when you need to wash and/or dewater material. Contact McLanahan or your nearest authorized local dealer not only for pricing but for discussions on suitability and use for your application.

What key options should I consider?

Front supports, discharge chutes and protective top covers are a few options to consider.

What other technologies should I consider?

We'd love to talk with you about options for your application. Contact us or your nearest authorized local dealer for more information.