Screening Screw Conveyors

Centreless screw conveyors supplied

to the screenings handling industry

Screening Screw Conveyors

All municipal waste water treatment plants screen for solids and grit found in the waste water, any solids must be removed at the start of the treatment process to ensure the screw conveyor systems are snag free and efficient and remain cost effective.

The serpecon screening screw conveyors are classified based on the size of the screening openings and the substances they will be conveying.

We classify water treatment screens as either:

  • Micro Screening

  • Fine Screening

  • Coarse Screening




The finest type of screening in waste water treatment is micro screening. These screens are typically low-speed drum screens. The drums are lined with filtering fabrics. Waste water then enters the drum via the screw conveyor, and the retained solid waste is collected and removed.


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The screening process in fine waste water treatment plants ensures the screens have clear openings of less than 6mm called fine screens which are used to remove fine solids from the water.




Coarse screen conveyors have much larger openings ranging from 6 to 150 mm. Coarse screens consist of parallel bars, rods or wires, wire mesh or perforated plates with openings generally of circular or rectangular shapes. It is also called a “bar rack” and used to remove coarse solids such as rags and large objects that will damage to the screw spiral by snagging and clogging.

Based on the wastewater screening method used to clean the screenings themselves, coarse screens are classified into two types:

  • Hand cleaned coarse screens these are hand raked and are deal to use as a standby during periods of high-flow, or when your mechanical screening equipment is under repair or being serviced.

  • Mechanically cleaned screens increase efficiency by reducing problems that may be found in the wastewater treatment process by automating the screening conveyors cleaning process, these mechanically cleaned screens can be classified into four main categories:

  • Reciprocating Rake Screens: These wastewater treatment screening solutions use one rake rather than multiple, making them less efficient during the screening process in water treatment especially during heavy loads.

  • Continuous Belt Screen: This type of waste water screening has multiple rakes is continuous and self-cleaning, whether facing fine or coarse solids.

  • Catenary Screens: Chain driven, front return and cleaned screens use internal mechanics to prevent further jamming in the presence of large or heavy objects which could snag or clog and damage the screw conveyor.

  • Chain Driven Screens: Front and back chain driven screens which rake upstream or downstream, an automatic chain cleans the stream, increasing the functionality of the entire wastewater treatment solution.

Whether you require a bespoke or standard screening solution, we are able to offer conveying systems with spray bars and drain decks.

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