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Dual-Flow Band Screens

Dual-flow (double-entry) band screens — water enters both outer faces and exits through a central duct, doubling capacity and eliminating carryover in width-constrained intakes.

Dual-Flow Band Screens

Intake Screening for Water & Desalination Plants

A dual-flow screen takes water through both the ascending and descending faces from the outside in, with the screened water collected in a central effluent duct. Like centre-flow it uses both faces (double capacity, no carryover) but with the opposite, outside-in flow path. Debris is captured on the outer faces and washed clear at the top.

Background & History

Dual-flow screens emerged alongside centre-flow designs as engineers sought to maximise screening area within a fixed channel width. By making both faces active with a central exit, dual-flow screens roughly double the capacity of a same-width through-flow screen — making them a favourite for retrofits and sites where intake-channel width is constrained.

Types & Variants

Configurations in service

Double-Entry, Single-Exit

Both outer faces screen; flow exits via a central effluent duct.

Width-Saving Geometry

Double area per width — ideal where channel width is limited.

Outer-Face Spray-Wash

Debris washed from both outer faces into collection troughs.

Fish-Handling Option

Bucket and return systems available for ecological compliance.

Advantages & Limitations

An honest engineering assessment

Advantages

  • No carryover to the clean side
  • Double screening area per width — very compact, low head loss
  • High capacity in narrow channels; excellent for retrofits
  • Robust performance under variable debris

Limitations

  • Central effluent ducting adds complexity
  • Debris on the outer faces needs effective, reliable wash
  • Higher capital cost than a simple through-flow screen

Where It Fits

Typical applications

Dual-flow band screens suit width-constrained intake channels, retrofits of existing structures, and large cooling-water and desalination intakes needing maximum capacity in minimum civil width.

Other Intake Screen Types

The full intake-screen series

Related Equipment & Hubs

Specify the right intake screen

Our engineers select and size intake screening — dual-flow band and the full train — matched to your debris load, fish-protection duty and downstream process.

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