Coarse Screening

Defender multirake bar screen


multi rake

The Defender Vertical Bar Screen from Johnson Screens is a bar screen with a spacing from 6 to 60mm. The bar rack is an integral part of the sturdy frame, which ensures perfect meshing of the rake teeth with the bar spaces. Positive and reliable cleaning is thus guaranteed.

A multitude of rake bars are bolted at selectable distances to a pair of drive chains. With short distances between its rakes, the Defender Vertical Bar Screen is able to remove extremely high screenings loads. The rake blades are made of sections that are bolted to the rake bars, thus facilitating easy replacement of a segment in case that its teeth should become damaged or worn. The Defender Vertical Bar Screen is the ideal screen for the following applications:

  • Combined sewer systems
  • Deep to very deep channels
  • High screenings loads
  • Combined sewer
  • Storm water
  • Raw water Intakes

Defender Cable Rake Bar Screen


cable rake

Johnson Screens® Defender Cable Rake Bar Screen is a vertical, cable driven coarse screen suitable for screening of sewage, storm water or raw water intakes.

The screen is typically installed in a pumping station or at the inlet of sewage or water treatment plants; The submerged section in contact with the influent is a series of parallel bars that make up the fixed bar screen. These parallel bars retain solids greater than the bar spacing as the influent flows through. The retained solids are then extracted by means of a cable-driven, raking system which lifts the solids outside the channel and discharges into a hopper.

The raking system comprises of a bucket with teeth on one side and supported by three cables and is activated by the water level differential in the channel.

T Rake Screen


trake

The Type T Wire Rope Front Rake Screen is installed in the
influent channel to prevent the coarse screenings, solids and
floating objects from entering the pump station. Screenings will
be removed from the bar rack and discharged onto a conveyor
enroute to a skip for eventual disposal.

Design Advantages


  • Simple in construction and yet provides sufficient raking capacities in severe conditions (eg. typhoon, wetlands or hydro dams).
  • Available in inclined configuration or vertical configuration for deep channels to reduce space and construction cost.