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Through-Flow Travelling Band Screens

Through-flow (thru-flow) travelling water screens — the proven workhorse fine screen for water and desalination intakes, with flow passing straight through ascending and descending screen baskets.

Through-Flow Travelling Band Screens

Intake Screening for Water & Desalination Plants

In a through-flow band screen, raw water passes through the front (ascending) face of an endless belt of mesh baskets. Debris collects on the baskets, which travel up, are spray-washed into a debris trough, and the cleaned baskets return down the back face. It is the original and most common travelling-screen configuration, screening typically 1–10 mm.

Background & History

Travelling water screens were developed in the early twentieth century (from the 1890s–1920s) to protect steam-condenser cooling-water intakes at power stations. The through-flow arrangement — water entering the front face and exiting the rear — was the original design and remains the most widely installed type a century later, refined with fish-handling (Ristroph) buckets and dual spray-wash.

Types & Variants

Configurations in service

Front-Clean / Front-Return

Debris washed off on the rising front face; simplest, most common layout.

Dual Spray-Wash

High-pressure debris wash plus low-pressure fish-return spray on Ristroph baskets.

Fish-Handling (Ristroph) Baskets

Lifting buckets and low-pressure return troughs release impinged fish alive.

In-Channel or Frame-Mounted

Concrete-channel or self-contained frame units to suit civil arrangement.

Advantages & Limitations

An honest engineering assessment

Advantages

  • Simple, proven, robust design with the longest track record
  • Lowest capital cost of the band-screen family
  • Easy access and straightforward maintenance
  • Wide capacity and mesh-size range (1–10 mm)
  • Fish-friendly Ristroph option well developed

Limitations

  • Debris “carryover” — material can be carried over the top to the clean side
  • Higher head loss than centre/dual-flow at the same capacity
  • Larger footprint per unit flow (only one face screens)
  • Less suited to very heavy or fibrous debris and jellyfish blooms

Where It Fits

Typical applications

Through-flow band screens suit power-station cooling-water intakes, river and reservoir abstraction, and moderate-debris desalination intakes where capital cost and simplicity are priorities and carryover is acceptable.

Other Intake Screen Types

The full intake-screen series

Related Equipment & Hubs

Specify the right intake screen

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

Industries We Serve

Our expertise spans multiple industries with sector-specific water treatment solutions.

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