What is aggregate screening
Aggregate screening equipment is used to classify and sort rock, stone, sand, construction rubble and other materials by size to produce finished aggregate products that meet specification requirements for use in construction materials like base gravel, concrete and asphalt.
The screening process is arguably the most important process in aggregate production. Unlike crushers that crush rock and produce material, screens only size material that has been reduced in size by the crusher. The crusher produces the gradation, but the screen produces the specification. Until the crushed material is successfully screened, no money is made.
Material is fed onto a vibrating screen box that contains 1 to 4 carry decks with different sizes of screen media (mesh) attached. As the feed material travels across the screen, it falls through the screen openings onto conveyors for stockpiling or further processing.
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Types of screening machines
While all screens are developed to sort and classify material by size, some are application-specific and designed to perform a specific range of duties like scalping, washing, and dewatering. The type of screen required depends on the application and material required.
Scalping Screens
Grizzly Bars and Grizzly Feeders are the most common types of screens used for primary scalping. They are used to pre-screen (scalp) and remove over or undersized rock and other undesirable material that could cause damage or affect the overall performance of the crusher.
Optimizing crusher performance at this stage also improves liner wear and reduces downtime.
Wash Screens
Washing screens, also known as wet screens, are used to remove unwanted materials like silt, rock dust, and organic material from rock, stone, and sand to produce material that meets construction specifications.
Dewatering Screens
Dewatering screens have a wide range of uses, including removing water and slime and scrubbing washed sand, rock and stone. They produce a drip-free product that is immediately usable or salable.
Trommel Screens
Trommel screens are versatile screens used to separate and process wood chips, topsoil, compost, light demolition waste, domestic waste and aggregates.
Unlike their vibrating counterparts, the rotating drum of trommel screens causes the material to spin inside of the tube. When it reaches the top of the drum, gravity takes over and the screened material falls back to the bottom and breaks up while it tumbles. The process repeats until the material is small enough to pass through the screen. The oversize material continues to travel the length of the screen and is discharged through the end of the tube.
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Learn more about our brands.
Powerscreen Inclined and Scalping Screens:
- Warrior heavy-duty scalping screens – Recycling, Aggregates, Compost, Topsoil, Coal, C&D Waste
- Chieftain mobile inclined screens – Aggregates, sand
Evoquip Compact Screens are built to excel in both heavy-duty scalping and precision screening applications in aggregates, sand & gravel, construction and demolition.
- Evoquip Colt Compact Screens
- Evoquip Harrier
Track Mounted or Wheeled Portable Washing Screens
- Integrated feed hopper and onboard discharge conveyors
- Quick set up time typically under 15 minutes
