fine material screw washers | mclanahan
Fine Material Screw Washers wash, classify and dewater -10mm or 3/8 solids material in one machine. They often accept feed slurry from Wash Screens, Sand Classifying Tanks, Hydrocyclones, Hydrosizers and other Fine Material Screw Washers. If an application calls for a greater level of dewatering, they are often placed in series with a Dewatering Screen.
Fine Material Screw Washers are especially simple for operations looking to wash dry screened fines. When compared to other sand washing systems, Screw Washers are a low-capital cost and low electric power user machine. They are widely used by construction sand producers, mining companies, solar salt/brine processors and glass recycling plants.
McLanahan offers an extensive range of sizes of Fine Material Screw Washers. Sizing and selection is based on several factors, including the type of feed solids, feed gradation, desired product specification, capacity required and volume of the feed slurry. It is extremely important that all of these factors are taken into consideration when selecting the proper size of screw washer. Poor design and planning can lead to overflow of desired fine material, resulting in lost product and profit. McLanahan Corporations utilizes its vast experience in washing and classifying equipment to ensure proper machine size by reviewing application data that includes slurry volume and your feed gradation data of water coming in with the feed.
Sometimes when processing a very dilute sand slurry, such as at a stone rinsing vibrating screen station, and needing to retain +200 mesh or 75 micron solids, a sand screw size selection may need to be larger than what appears to be required when the solids feed rate isnt that much. If you look at a manufacturers tons per hour data, a machines water volume capacity may not meet your needs for fine sand solids retention based on the water volume capacity chart.
McLanahan Corporation offers a wider range of Fine Material Sand Screws than other manufacturers. High Water Volume Screw Washers are available sizes that allow the mixing and matching of a screw shaft size to handle a reduced capacity of sand solids with a washer box tub to handle a larger than normal water volume. This provides a lower cost option as compared to a larger standard sand screw. If the sand capacity is 50 tph with 1,000 gallons per minute of water, a 36 diameter screw shaft can be provided in a 54 washer box tub.
High Water Volume Screw Washers have been in operation since 2002, providing operators a proper alternative with increased product sized sand fines retention, as opposed to a standard machine selected incorrectly for just the tons per hour sand solids capacity.
To achieve the desired results with a Fine Material Screw Washer, sand or other fine material is directed to the feed box in the baffle plate. Coarse, heavier materials settle to the bottom of the box, while ultra-fine waste fractions are carried by the up-current of water to the surface and overflow the weirs.
Heavier material that settles to the bottom is conveyed up an 18-degree slope toward the discharge end. The rolling and tumbling of the material releases fines and some lightweight fractions into suspension. It also mildly scrubs superficial clays from the sand/mineral surfaces. As the material is conveyed toward the discharge end, the water begins to separate from the material. A channel in the washer box/tub is provided opposite the conveying side to allow water to drain from the solids and overflow the weirs.
In order to properly retain material in a screw washer, a calm pool area must be maintained. The feed box within the baffle plate is used to direct material away from the calm pool area; however, if the pool area is turbulent, finer material that may be desirable in the final product will overflow the weirs. The baffle plate helps to separate the washer box feed area and keep the pool area calm. In some applications, producers may remove the baffle plate and feed the material close to the back plate of the weir to help agitate the pool area and overflow undesirable material.
The speed of the Fine Material Screw Washer is determined by the percent passing 50 mesh in the desired product. If the screw washer is running too fast, material does not have a chance to stay on the flight long enough to dewater. The material will fall off of the flight and return to the pool area, leading the box to eventually fill with sand and stall the screw shaft.
Fine Material Screw Washers are widely used to wash and dewater: alluvial/natural sands, manufactured/crushed sands, frac sands, industrial/silica sands, iron ore fines, fine phosphate solids, solar evaporated salt solids and crushed glass.
Hydrocyclones, Dewatering Screen systems using a Hydrocyclone, and bucket wheels. Youll find that for the cost and low kW (hp) requirements, a Fine Material Screw Washer will be an extremely viable option and a good choice for you.
Functioning to wash, dewater and classify all solids material all in one machine, McLanahan Fine Material Screw Washers are ideal for construction sand producers, mining companies, salt/brine reclamation and glass recycling. Fine Material Screw Washers create a drier product discharge, while preventing water and even the smallest particles from reaching the bearing thanks to the McLanahan Twin-Seal Pak submerged rear bearings.
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Following is a list of aggregate equipment machine categories for which Aggregate Equipment Sales offers parts. An AES part list is available as a PDF for each machine and references part numbers for EIW (both old and new) and the AES part number.