Flap Filter Underdrain

Flap Filter
Bread Pipe

Also called a U-shaped filter pipe: a single profiled pipe laid in rows across a flap filter floor that collects filtrate during service and distributes air, then air and water, then wash water during backwash. Supplied in HDPE or stainless steel 304 and formed to your filter drawing.

Request a Quote Technical Details

U-sectionProfile

HDPE · SS304Material

Made to orderLength

On requestPrice

Flap filter bread pipe — U-section pipe with slotted base flange

Type

U-section bread pipe

Material

HDPE · stainless steel 304

Duty

Water · air · collection

Length

Made to order

Price

On request

Why this bread pipe

One pipe, three duties

A filter floor needs a path for the filtrate, a path for the scour air and a path for the wash water. A bread pipe provides all three from the same element, laid in rows across the cell.

Water, air and collection

During service the pipe collects filtrate from the bed; during backwash it distributes air, then air together with water, then water on its own. One row of pipes serves the whole cycle, so the floor carries fewer parts than a plate-and-nozzle bottom.

Two air cushions, no pulsing

The arrangement works with an upper air cushion above the distribution channel and a lower one at the crown of the transverse pipes. Together they hold the air steady and spread air and water over the whole cell, so the bed is not scoured in pulses or only near the inlet.

Made to your filter drawing

HDPE and stainless steel 304 both resist acid and alkali and adsorb very little. The pipe is preformed, cut and slotted to your cell dimensions, which keeps installation quick and the demand on civil works low — and it suits retrofits as readily as new cells.

Specifications

Technical parameters

Parameter	Value
Product	U-section (bread) filter pipe for flap filter and air-water wash filter floors
Section	U-shaped — arched crown on a flat base flange, with openings in a staggered pattern along the body
Material	HDPE (polyethylene) · stainless steel 304
Length	Made to order to the filter drawing; transverse runs are published at 2–4 m
Section size & slot layout	On request — set by the cell size, pipe spacing and backwash rates
Service temperature	−20 to 80 °C (published range)
Corrosion behaviour	Acid- and alkali-resistant, low adsorption, non-clogging (published)
Load capacity	1 t/m² (published)
Friction coefficient	Below 0.05 (published)
Fixing system	Support blocks, riser clamps, upper and lower riser locating plates, 304 expansion bolts
Media compatibility	Single-layer, dual-layer or multi-layer beds, with a graded gravel support layer between the pipes
MOQ / price	On request — confirm section, length, material & destination

Values marked “published” are ranges reported in public supplier and industry references; they are confirmed against the order drawing before shipment. Section size, slot opening and length are project-specific and are quoted On request.

Applications

Where it fits

Flap-valve filtersCombined air-and-water wash filtersDenitrification filtersConventional filters converted from single-water washMunicipal water plantsIndustrial water — cooling water & boiler feed waterWastewater tertiary treatmentWater reuse

Product gallery

See the pipe up close

Close-up of a white bread pipe end and slotted base flange

Single white HDPE bread pipe for a flap filter floor

Bread pipe end in the workshop after forming

Rows of white bread pipes laid out at the factory

Bread pipes stacked and ready for dispatch

Two black bread pipes of different lengths

Bread pipes installed in rows on a filter floor

More filter-floor equipment

Denitrification Filter Brick

Air & water distribution block

ABS Filter Nozzle

Plate-mounted distribution

BS Cast-in-place Filter Plate

Monolithic filter bottom

Concrete Filter Plate

Precast nozzle deck

Send us your filter drawing

Cell size, pipe spacing and the air and water backwash rates are enough for us to confirm the section, slot layout, material and export packing — and to quote.

Request a QuoteNo obligation · response within 24h (working days)

Flap FilterBread Pipe