Stainless Steel Hexagonal Tube Settler · Technical Reference & Specifications

Hexagonal Honeycomb Packing — the Inclined Tube Settler

Hexagonal honeycomb packing is a block assembled from straight hexagonal tubes, used in either inclined-tube or straight-tube form. The inclined form is the tube settler applied to sedimentation and desanding, and is one of the most widely used and mature settling devices in water supply and drainage engineering. It gives a large wetted perimeter and a small hydraulic radius, so flow remains stable and laminar and particle settling is not disturbed by turbulence.

The standard block is built from hexagonal cells with a typical panel size of 1000 × 500 × 1000 mm, installed at 60°. Cell size sets both the surface area and the risk of clogging: smaller cells give a higher surface area and a shorter settling path, while larger cells pass more solids and grit. Matching cell size to the solids load is the single most important selection decision.

Materials

Hexagonal honeycomb packing is made in polypropylene (PP), polyvinyl chloride (PVC), co-polymer (ethylene-propylene), glass fibre (FRP) and stainless steel. Stainless steel is chosen where a plastic panel is not suitable — hot process water, abrasive grit and desanding duty, or a chemically aggressive stream — because the metal block holds its cell geometry under load and does not suffer the ageing and creep of thermoplastics.

Stainless Steel Construction

The block is assembled from straight hexagonal tubes formed from stainless steel sheet. Because the cells are rigid and self-supporting, the passage size that governs settling stays constant across the panel and over the depth of the stack, and the module can be fabricated to suit the basin plan rather than the basin being adapted to a fixed module size.

What we confirm with you

• Grade — selected against the water chemistry (chloride content, pH, temperature) and the cleaning regime.
• Sheet thickness — set by cell size, panel span, stack height and the mechanical load during handling and cleaning.
• Cell size — Φ25 – 90 mm available; the working size follows the solids load and the required effluent quality.
• Panel dimensions and assembly — standard 1000 × 500 × 1000 mm, with custom dimensions, edge trim and support detail to suit the tank.

Surface area, porosity, bulk mass and service life all follow from the grade, sheet thickness and cell size, so they are quoted on request against a specific configuration rather than published as a single figure.

Main Performance Parameters

Table A — Geometric and material parameters (project-specific)

Parameter	Value
Material	Stainless steel — grade confirmed against the water chemistry
Structure	Straight hexagonal tubes assembled into a honeycomb block
Cell (pore) size	Φ25 / 35 / 50 / 60 / 80 / 90 mm (other sizes on request)
Panel size	1000 × 500 × 1000 mm (custom dimensions on request)
Installation angle	60°
Sheet thickness	0.5 – 0.8 mm
Surface area	62 – 236 m²/m³
Porosity	93 – 97%
Bulk density	On request — depends on the grade used
Service life	On request — set by water chemistry and cleaning regime

Table B — Standard inclined-tube settler design values (1 m tube length; not material-specific)

Parameter	Value
Design velocity V₀	2.5 – 3.0 mm/s
Effective hydraulic load	3 – 5 t/(m²·h)
Capacity, tube-settler basin	3 – 5× a horizontal-flow basin; 2 – 3× an accelerated or pulse clarifier
Lamella board thickness	0.4 / 0.5 / 0.8 mm (Φ35 / 50 / 80)
Stack height	4 – 5 m
COD removal	85 – 90%
Sediment content at intake	50 – 100 kg/m², with tubes 2.0 – 3.0 m long
Tube length in settling zones	1 m typical; 2.0 – 3.0 m at high-solids intakes
Stack height	4 – 5 m
Gap between layers	200 – 300 mm, with each layer no more than 1.5 m high

Table B lists the standard design values for inclined-tube settlers from the reference literature; they describe the geometry of the process, not the stainless steel block itself, and are to be verified against the project design.

Design & Installation Notes

1. Install panels at 60°, so settled sludge slides down the cell wall into the sludge zone and does not deposit on the surface.
2. Match cell size to the solids load. If the cell is too small for the load, solids bridge the passage and the settling efficiency falls sharply.
3. Keep the velocity inside the cells uniform. Uneven inlet distribution or a badly arranged outlet channel is the usual cause of poor performance, not the media itself.
4. Where layers are stacked, leave a 200 – 300 mm gap between them and keep each layer no more than 1.5 m high, so water redistributes between layers and lower layers are not deformed by the weight above.
5. Provide a level support frame. The stainless block is rigid but the frame carries the stack, and a distorted support opens gaps that bypass the media.
6. Design the sludge hopper and the sludge withdrawal around the expected grit load — the tube section settles solids quickly, so the underflow must remove them at the same rate.
7. For retrofits, the stainless module can be dimensioned to the existing basin, which makes it practical to raise capacity of an existing flat or short-retention basin without civil works.

Main Applications

The inclined tube settler is used for sedimentation and desanding across water supply and wastewater engineering: inlet desanding, general industrial and municipal water settling, oil separation and tailings thickening, in both new projects and retrofits of existing tanks. Settling basins fitted with hexagonal honeycomb packing settle faster, which shortens settling time and raises output and water quality — an effective way to expand and upgrade water and wastewater plants. Stainless steel panels are specified in the same duties when the water is hot, abrasive or chemically aggressive, or where the media must be cleaned mechanically.

Notes on Sources

Honeycomb packing and inclined-tube settler structure, mechanism and design values are compiled from Water Treatment Packing & Filter Media (3rd Edition), §2.5. Stainless steel grade, sheet thickness, surface area, porosity, bulk density, service life and price are not published here: they depend on the water chemistry and the selected cell size, so they are confirmed per project and quoted on request. No performance figure on this page is a guarantee for a specific installation — ask us for the data sheet for your configuration.